This application is a continuation of International Patent Application No. PCT/JP2020/042914, filed on Nov. 18, 2020, which claims the benefit of Japanese Patent Application No. 2020-013666, filed on Jan. 30, 2020, the contents all of which are incorporated herein by reference.

›TECHNICAL FIELD

The present disclosure relates to an optical system that forms an intermediate image. The present disclosure also relates to an image projection apparatus and an imaging apparatus using such an optical system.

›BACKGROUND

Intermediate imaging-based optical systems have an advantage of achieving wide-angle projection with a short focal length and a wide screen, while the total length of the optical system tends to be increased, thereby rendering the optical system heavier. When attaching a portion of the optical system to an outside of a hosing of an image projection apparatus body, a moment acting on the center of gravity may cause the optical system to tilt relative to the apparatus body, thereby possibly degrading the optical performance.

In order to reduce a weight of the optical system, it may be conceived that a lens made of a synthetic resin is used in lieu of a lens made of glass. Such a synthetic resin has a smaller specific gravity, a smaller thermal conductivity and a larger coefficient of linear expansion as compared to glass. Thus, the optical system can be lightweight. However if local temperature elevation and thermal deformation take place, some optical aberrations, in particular, chromatic aberration tends to be increased. This tendency is more remarkable in case of high-intensity projection.

Patent Document 1 discloses a wide-angle imaging optical system, wherein the first lens L 1 a positioned closest to the magnification conjugate point has the largest diameter. The first lens L 1 a has aspherical double surfaces with quite complicated shapes, hence, it could be imagined to use a synthetic resin lens. However, such complicated aspherical shapes tend to be sensitive to thermal deformation. Therefore, it is expected that optical aberrations may be significantly degraded due to temperature elevation.

›PATENT DOCUMENT

[Patent Document 1] JP 2019-174633 A

›SUMMARY

The present disclosure provides an optical system that can reduce a moment acting on the center of gravity. The present disclosure also provides an image projection apparatus and an imaging apparatus using such an optical system.

One aspect of the present disclosure is directed to an optical system internally having an intermediate imaging position that is conjugated to a magnification conjugate point on a magnification side and a reduction conjugate point on a reduction side, respectively, the optical system including:

a magnification optical system having a plurality of lens elements, positioned on the magnification side with respect to the intermediate imaging position; and a relay optical system having a plurality of lens elements, positioned on the reduction side with respect to the intermediate imaging position, wherein there are a plurality of air distances among the lens elements, the magnification optical system includes a magnification optical system front group positioned on the magnification side with respect to the longest air distance along an optical axis in the magnification optical system and a magnification optical system rear group positioned on the reduction side with respect to the longest air distance, and the optical system satisfies the following conditions (1) and (2):

7<| Ts/fw|< 15 (1)

2<| Tpr/fw|< 7 (2)

where, Ts is the longest air distance, fw is a focal length of the entire optical system at a wide-angle end thereof, and Tpr is a distance from a surface closest to the magnification side of the magnification optical system rear group to the intermediate imaging position.

Further, an image projection apparatus according to the present disclosure includes the above-described optical system and an image forming element that generates an image to be projected through the optical system onto a screen.

Still further, an imaging apparatus according to the present disclosure includes the above-described optical system and an imaging element that receives an optical image formed by the optical system to convert the optical image into an electrical image signal.

The optical system according to the present disclosure can reduce a moment acting on the center of gravity. Therefore, the optical system can be stably mounted onto a body of an apparatus.

›BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a layout diagram showing an optical path at a wide-angle end in a zoom lens system of example 1 for an object distance of 1066 mm.

FIGS. 2 A- 2 C are layout diagrams of the zoom lens system of example 1 for an object distance of 1066 mm.

FIGS. 3 A- 3 C are longitudinal aberrations diagram of the zoom lens system of example 1 for an object distance of 1066 mm.

FIG. 4 is a layout diagram showing an optical path at a wide-angle end in a zoom lens system of example 2 for an object distance of 1066 mm.

FIGS. 5 A- 5 C are layout diagrams of the zoom lens system of example 2 for an object distance of 1066 mm.

FIGS. 6 A- 6 C are a longitudinal aberration diagrams of the zoom lens system of example 2 for an object distance of 1066 mm.

FIG. 7 is a layout diagram showing an optical path at a wide-angle end in a zoom lens system of example 3 for an object distance of 1066 mm.

FIGS. 8 A- 8 C are layout diagrams of the zoom lens system of example 3 for an object distance of 1066 mm.

FIGS. 9 A- 9 C are longitudinal aberration diagrams of the zoom lens system of example 3 for an object distance of 1066 mm.

FIG. 10 is a layout diagram showing an optical path at a wide-angle end in a zoom lens system of example 4 for an object distance of 1066 mm.

FIGS. 11 A- 11 C are layout diagrams of the zoom lens system of example 4 for an object distance of 1066 mm.

FIGS. 12 A- 12 C are longitudinal aberration diagrams of the zoom lens system of example 4 for an object distance of 1066 mm.

FIG. 13 is a layout diagram showing an optical path at a wide-angle end in a zoom lens system of example 5 for an object distance of 1066 mm.

FIGS. 14 A- 14 C are layout diagrams of the zoom lens system of example 5 for an object distance of 1066 mm.

FIGS. 15 A- 15 C are longitudinal aberration diagrams of the zoom lens system of example 5 for an object distance of 1066 mm.

FIG. 16 is a layout diagram showing an optical path at a wide-angle end in a zoom lens system of example 6 for an object distance of 1066 mm.

FIGS. 17 A- 17 C are layout diagrams of the zoom lens system of example 6 for an object distance of 1066 mm.

FIGS. 18 A- 18 C are longitudinal aberration diagrams of the zoom lens system of example 6 for an object distance of 1066 mm.

FIG. 19 is a layout diagram showing an optical path at a wide-angle end in a zoom lens system of example 7 for an object distance of 1066 mm.

FIGS. 20 A- 20 C are layout diagrams of the zoom lens system of example 7 for an object distance of 1066 mm.

FIGS. 21 A- 21 C are longitudinal aberration diagrams of the zoom lens system of example 7 for an object distance of 1066 mm.

FIG. 22 is a block diagram showing an example of an image projection apparatus according to the present disclosure.

FIG. 23 is a block diagram showing an example of an imaging apparatus according to the present disclosure.

›DESCRIPTION OF EMBODIMENT · 1 of 2

Hereinafter, embodiments are described in detail with reference to the drawings as appropriate. However, unnecessarily detailed descriptions may be omitted. For example, detailed descriptions of well-known items or redundant descriptions of substantially the same configurations may be omitted. This is to prevent the following description from being unnecessarily redundant and to facilitate understanding by those skilled in the art.

It should be noted that the applicant provides the accompanying drawings and the following description for those skilled in the art to fully understand the present disclosure, and it is not intended to limit the subject matter described in the claims thereby.

Each example of an optical system according to the present disclosure is described below. In each example, described is an example in which the optical system is used in a projector (an example of an image projection apparatus) that projects onto a screen image light of an original image S obtained by spatially modulating incident light using an image forming element, such as liquid crystal or digital micromirror device (DMD), based on an image signal. In other words, the optical system according to the present disclosure can be used for magnifying the original image S on the image forming element arranged on the reduction side to project the image onto the screen (not shown), which is arranged on an extension line on the magnification side.

Further, the optical system according to the present disclosure can also be used for collecting light emitted from an object located on the extension line on the magnification side to form an optical image of the object on an imaging surface of an imaging element arranged on the reduction side.

First Embodiment

Hereinafter, a first embodiment of the present disclosure is described with reference to FIGS. 1 to 21 . Here, a zoom lens system is described as an example of the optical system.

FIGS. 1 , 4 , 7 , 10 , 13 , 16 and 19 are layout diagrams each showing an optical path at a wide-angle end in a zoom lens system according to any of examples 1 to 7 for an object distance of 1066 mm. FIGS. 2 A- 2 C, 5 A- 5 C, 8 A- 8 C, 11 A- 11 C, 14 A- 14 C, 17 A- 17 C and 20 A- 20 C are layout drawings of the zoom lens system according to examples 1 to 7 for an object distance of 1066 mm. FIGS. 2 A, 5 A, 8 A, 11 A, 14 A, 17 A and 20 A are lens arrangement diagrams at the wide-angle end in the zoom lens system. FIGS. 2 B, 5 B, 8 B, 11 B, 14 B, 17 B and 20 B are lens arrangement diagrams at an intermediate position in the zoom lens system. FIGS. 2 C, 5 C, 8 C, 11 C, 14 C, 17 C and 20 C are lens arrangement diagrams at a telephoto end in the zoom lens system.

The wide-angle end is defined as the shortest focal length state in which the entire optical system has the shortest focal length fw. The intermediate position is defined as an intermediate focal length state between the wide-angle end and the telephoto end. The telephoto end is defined as the longest focal length state in which the entire optical system has the longest focal length ft. By using the focal length fw at the wide-angle end and the focal length ft at the telephoto end, the focal length fm at the intermediate position can be defined as fm=√(fw×ft) (√: square root).

The zoom lens system according to example 1 includes a first lens group G 1 to a fourth lens group G 4 and an optical element P. The first lens group G 1 having a positive power is constituted of a first lens element L 1 to a 15th lens element L 15 , including a surface 1 to a surface 30 (see the numerical examples described later). The second lens group G 2 having a positive power is constituted of a 16th lens element L 16 to a 18th lens element L 18 , including a surface 31 to a surface 36 . The third lens group G 3 having a negative power is constituted of a 19th lens element L 19 to a 22nd lens element L 22 , including a surface 37 to a surface 45 . The fourth lens group G 4 having a positive power is constituted of a 23rd lens element L 23 to a 25th lens element L 25 , including a surface 46 to a surface 51 . The optical element P includes a surface 52 to a surface 53 .

The zoom lens system according to example 2 includes a first lens group G 1 to a fourth lens group G 4 and an optical element P, which is similar to example 1, thus redundant descriptions thereof is omitted.

The zoom lens system according to example 3 includes a first lens group G 1 to a fourth lens group G 4 and an optical element P. The first lens group G 1 having a positive power is constituted of a first lens element L 1 to a 16th lens element L 16 , including a surface 1 to a surface 32 (see the numerical examples described later). The second lens group G 2 having a positive power is constituted of a 17th lens element L 17 to a 19th lens element L 19 , including a surface 33 to a surface 38 . The third lens group G 3 having a negative power is constituted of a 20th lens element L 20 to a 23rd lens element L 23 , including a surface 39 to a surface 47 . The fourth lens group G 4 having a positive power is constituted of a 24th lens element L 24 to a 26th lens element L 26 , including a surface 48 to a surface 53 . The optical element P includes a surface 54 to a surface 55 .

Polygonal line arrows shown between each of FIGS. 2 A, 5 A, 8 A, 11 A, 14 A, 17 A and 20 A and each of FIGS. 2 B, 5 B, 8 B, 11 B, 14 B, 17 B and 20 B include straight lines obtained by connecting the positions of the first lens group G 1 to the fourth lens group G 4 corresponding to each of the states of the wide-angle end, the intermediate position, and the telephoto end ranked in order from the top in the drawing. The wide-angle end and the intermediate position, and the intermediate position and the telephoto end are simply connected by a straight line, which is different from the actual movement of each of the lens groups G 1 to G 4 . The symbols (+) and (−) attached to the reference numerals of the respective lens groups G 1 to G 4 indicate the positive or negative power of each of the lens groups G 1 to G 4 .

›DESCRIPTION OF EMBODIMENT · 2 of 2

The zoom lens systems according to examples 1 to 7 may include a focusing adjustment lens group that adjusts the focus when an object distance is changed, and a field curvature correction lens group that corrects the field curvature aberration after focus adjustment by the focusing adjustment lens group.

In each of the drawings, an imaging position on the magnification side (i.e., the magnification conjugate point) is located on the left side, and an imaging position on the reduction side (i.e., the reduction conjugate point) is located on the right side. Further, in each of the drawings, the straight line drawn closest to the reduction side represents a position of the original image S, and an optical element P is located on the magnification side of the original image S. The optical element P represents different optical elements, such as a prism for color separation and color synthesis, an optical filter, a flat-parallel glass plate, a crystal low-pass filter, and an infrared cut filter.

The zoom lens system according to each of examples 1 to 7 internally has an intermediate imaging position MI that is conjugated to the magnification conjugate point on the magnification side and the reduction conjugate point on the reduction side, respectively. Further, in each of the drawings, a magnification optical system Op is positioned on the magnification side with respect to the intermediate imaging position MI, and a relay optical system O 1 is positioned on the reduction side with respect to the intermediate imaging position MI.

In the zoom lens system according to each of examples 1 to 7, there are a plurality of air distances among the first lens element L 1 to the 25th lens element L 25 (or 26th lens element L 26 ) and the optical element P. The magnification optical system Op has the longest air distance along an optical axis in the magnification optical system. For example, in examples 1 and 2, as shown in FIGS. 2 A and 5 A , there is the longest air distance between the 10th lens element L 10 and the 11th lens element L 11 . The magnification optical system Op includes magnification optical system front group Opf positioned on the magnification side with respect to the longest air distance and a magnification optical system rear group Opr positioned on the reduction side with respect to the longest air distance. The front group Opf and the rear group Opr may have a single lens element or plural lens elements.

FIGS. 3 A- 3 C, 6 A- 6 C, 9 A- 9 C, 12 A- 12 C, 15 A- 15 C, 18 A- 18 C and 21 A- 21 C are longitudinal aberration diagrams of the zoom lens system according to examples 1 to 7 for an object distance of 1066 mm. FIGS. 3 A, 6 A, 9 A, 12 A, 15 A, 18 A and 21 A show longitudinal aberration diagrams at the wide-angle end of the zoom lens system, and FIGS. 3 B, 6 B, 9 B, 12 B, 15 B, 18 B and 21 B show longitudinal aberration diagrams at the intermediate position, and 3 C, 6 C, 9 C, 12 C, 15 C, 18 C and 21 C show longitudinal aberration diagrams at the telephoto end.

Each of the longitudinal aberration diagrams shows spherical aberration (SA (mm)), astigmatism (AST (mm)), and distortion (DIS (%)) in order from the left side. In the spherical aberration diagram, the vertical axis represents a pupil height, and a solid line shows the characteristic of the d-line, a short dashed line shows the characteristic of the F-line, and a long dashed line shows the characteristic of the C-line. In the astigmatism diagram, the vertical axis represents an image height, and a solid line shows the characteristic of the sagittal plane (indicated by s in the drawing), and a dashed line shows the characteristic of the meridional plane (indicated by m in the drawing). In the distortion diagram, the vertical axis represents the image height. The distortion represents distortion with respect to equidistant projection.

›Examples12

›Example 1

As shown in FIGS. 1 and 2 A- 2 C , the zoom lens system according to example 1 includes the magnification optical system Op and the relay optical system O 1 . The magnification optical system Op is constituted of the first lens element L 1 to the 12th lens element L 12 . The magnification optical system Op includes the front group Opf and the rear group Opr.

The front group Opf of the magnification optical system Op is constituted of the first lens element L 1 to the 10th lens element L 10 in order from the magnification side to the reduction side. The first lens element L 1 has a negative meniscus shape with the convex surfaces facing the magnification side. The second lens element L 2 has a negative meniscus shape with the convex surfaces facing the magnification side. The third lens element L 3 has a negative meniscus shape with the convex surfaces facing the magnification side. The fourth lens element L 4 has a biconcave shape. The fifth lens element L 5 has a negative meniscus shape with the convex surfaces facing the reduction side. The sixth lens element L 6 has a positive meniscus shape with the convex surfaces facing the reduction side. The seventh lens element L 7 has a negative meniscus shape with the convex surfaces facing the reduction side. The eighth lens element L 8 has a positive meniscus shape with the convex surfaces facing the reduction side. The ninth lens element L 9 has a positive meniscus shape with the convex surfaces facing the reduction side. The 10th lens element L 10 has a positive meniscus shape with the convex surfaces facing the reduction side.

The rear group Opr of the magnification optical system Op is constituted of the 11th lens element L 1 l to the 12th lens element L 12 in this order from the magnification side to the reduction side. The 11th lens element L 11 has a biconvex shape. The 12th lens element L 12 has a positive meniscus shape with the convex surfaces facing the magnification side.

The relay optical system O 1 is constituted of the 13th lens element L 13 to the 25th lens element L 25 in order from the magnification side to the reduction side. The 13th lens element L 13 has a biconcave shape. The 14th lens element L 14 has a biconcave shape. The 15th lens element L 15 has a positive meniscus shape with the convex surfaces facing the reduction side. The 16th lens element L 16 has a biconvex shape. The 17th lens element L 17 has a negative meniscus shape with the convex surfaces facing the reduction side. The 18th lens element L 18 has a biconvex shape. The 19th lens element L 19 has a biconvex shape. The 20th lens element L 20 has a biconcave shape. The 21st lens element L 21 has a biconcave shape. The 22nd lens element L 22 has a biconvex shape. The 23rd lens element L 23 has a biconvex shape. The 24th lens element L 24 has a negative meniscus shape with the convex surfaces facing the magnification side. The 25th lens element L 25 has a biconvex shape.

The relay optical system O 1 is constituted of the first lens group (L 13 to L 15 ) having a negative power, the second lens group (L 16 to L 18 ) having a positive power, the third lens group (L 19 to L 22 ) having a negative power, and the fourth lens group (L 23 to L 25 ) having a positive power in order from the magnification side to the reduction side. During zooming the first lens group and the third lens group are fixed, and the second lens group and the fourth lens group are displaced along the optical axis.

By way of example, the first lens element L 1 corresponds to the first lens element recited in claims.

The intermediate imaging position MI is located between the 12th lens element L 12 and the 13th lens element L 13 . Further, an aperture A is arranged between the 19th lens element L 19 and the 20th lens element L 20 . The optical element P having zero optical power is arranged on the reduction side of the relay optical system O 1 .

›Example 2

As shown in FIGS. 4 and 5 A- 5 C , the zoom lens system according to example 2 includes the magnification optical system Op and the relay optical system O 1 . The magnification optical system Op is constituted of the first lens element L 1 to the 12th lens element L 12 . The magnification optical system Op includes the front group Opf and the rear group Opr.

The front group Opf of the magnification optical system Op is constituted of the first lens element L 1 to the 10th lens element L 10 in order from the magnification side to the reduction side. The first lens element L 1 has a negative meniscus shape with the convex surfaces facing the magnification side. The second lens element L 2 has a negative meniscus shape with the convex surfaces facing the magnification side. The third lens element L 3 has a negative meniscus shape with the convex surfaces facing the magnification side. The fourth lens element L 4 has a biconvex shape. The fifth lens element L 5 has a positive meniscus shape with the convex surfaces facing the reduction side. The sixth lens element L 6 has a positive meniscus shape with the convex surfaces facing the reduction side. The seventh lens element L 7 has a negative meniscus shape with the convex surfaces facing the reduction side. The eighth lens element L 8 has a positive meniscus shape with the convex surfaces facing the reduction side. The ninth lens element L 9 has a positive meniscus shape with the convex surfaces facing the reduction side. The 10th lens element L 10 has a biconvex shape.

The rear group Opr of the magnification optical system Op is constituted of the 11th lens element L 11 to the 12th lens element L 12 in this order from the magnification side to the reduction side. The 11th lens element L 11 has a biconvex shape. The 12th lens element L 12 has a positive meniscus shape with the convex surfaces facing the magnification side.

The relay optical system O 1 is constituted of the 13th lens element L 13 to the 25th lens element L 25 in order from the magnification side to the reduction side. The 13th lens element L 13 has a biconcave shape. The 14th lens element L 14 has a biconcave shape. The 15th lens element L 15 has a biconvex shape. The 16th lens element L 16 has a biconvex shape. The 17th lens element L 17 has a biconcave shape. The 18th lens element L 18 has a biconvex shape. The 19th lens element L 19 has a positive meniscus shape with the convex surfaces facing the magnification side. The 20th lens element L 20 has a negative meniscus shape with the convex surfaces facing the magnification side. The 21st lens element L 21 has a biconcave shape. The 22nd lens element L 22 has a biconvex shape. The 23rd lens element L 23 has a biconvex shape. The 24th lens element L 24 has a negative meniscus shape with the convex surfaces facing the magnification side. The 25th lens element L 25 has a biconvex shape.

By way of example, the first lens element L 1 corresponds to the first lens element recited in claims.

›Example 3

As shown in FIGS. 7 and 8 A- 8 C , the zoom lens system according to example 3 includes the magnification optical system Op and the relay optical system O 1 . The magnification optical system Op is constituted of the first lens element L 1 to the 13th lens element L 13 . The magnification optical system Op includes the front group Opf and the rear group Opr.

The front group Opf of the magnification optical system Op is constituted of the first lens element L 1 to the 11th lens element L 11 in order from the magnification side to the reduction side. The first lens element L 1 has a negative meniscus shape with the convex surfaces facing the magnification side. The second lens element L 2 has a negative meniscus shape with the convex surfaces facing the magnification side. The third lens element L 3 has a negative meniscus shape with the convex surfaces facing the magnification side. The fourth lens element L 4 has a biconcave shape. The fifth lens element L 5 has a biconvex shape. The sixth lens element L 6 has a biconcave shape. The seventh lens element L 7 has a biconvex shape. The eighth lens element L 8 has a negative meniscus shape with the convex surfaces facing the reduction side. The ninth lens element L 9 has a positive meniscus shape with the convex surfaces facing the reduction side. The 10th lens element L 10 has a positive meniscus shape with the convex surfaces facing the reduction side. The 11th lens element L 11 has a biconvex shape.

The rear group Opr of the magnification optical system Op is constituted of the 12th lens element L 12 to the 13th lens element L 13 in this order from the magnification side to the reduction side. The 12th lens element L 12 has a biconvex shape. The 13th lens element L 13 has a positive meniscus shape with the convex surfaces facing the magnification side.

The relay optical system O 1 is constituted of the 14th lens element L 14 to the 26th lens element L 26 in order from the magnification side to the reduction side. The 14th lens element L 14 has a biconcave shape. The 15th lens element L 15 has a biconcave shape. The 16th lens element L 16 has a positive meniscus shape with the convex surfaces facing the reduction side. The 17th lens element L 17 has a negative meniscus shape with the convex surfaces facing the magnification side. The 18th lens element L 18 has a biconvex shape. The 19th lens element L 19 has a biconvex shape. The 20th lens element L 20 has a biconvex shape. The 21st lens element L 21 has a biconcave shape. The 22nd lens element L 22 has a biconcave shape. The 23rd lens element L 23 has a biconvex shape. The 24th lens element L 24 has a biconvex shape. The 25th lens element L 25 has a negative meniscus shape with the convex surfaces facing the magnification side. The 26th lens element L 26 has a biconvex shape.

The relay optical system O 1 is constituted of the first lens group (L 14 to L 16 ) having a negative power, the second lens group (L 17 to L 19 ) having a positive power, the third lens group (L 20 to L 23 ) having a negative power, and the fourth lens group (L 24 to L 26 ) having a positive power in order from the magnification side to the reduction side. During zooming the first lens group and the third lens group are fixed, and the second lens group and the fourth lens group are displaced along the optical axis.

By way of example, the first lens element L 1 corresponds to the first lens element recited in claims.

The intermediate imaging position MI is located between the 13th lens element L 13 and the 14th lens element L 14 . Further, an aperture A is arranged between the 19th lens element L 19 and the 20th lens element L 20 . The optical element P having zero optical power is arranged on the reduction side of the relay optical system O 1 .

›Example 3

As shown in FIGS. 10 and 11 A- 11 C , the zoom lens system according to example 4 includes the magnification optical system Op and the relay optical system O 1 . The magnification optical system Op is constituted of the first lens element L 1 to the 12th lens element L 12 . The magnification optical system Op includes the front group Opf and the rear group Opr.

The front group Opf of the magnification optical system Op is constituted of the first lens element L 1 to the 10th lens element L 10 in order from the magnification side to the reduction side. The first lens element L 1 has a negative meniscus shape with the convex surfaces facing the magnification side. The second lens element L 2 has a negative meniscus shape with the convex surfaces facing the magnification side. The third lens element L 3 has a negative meniscus shape with the convex surfaces facing the magnification side. The fourth lens element L 4 has a biconvex shape. The fifth lens element L 5 has a positive meniscus shape with the convex surfaces facing the reduction side. The sixth lens element L 6 has a positive meniscus shape with the convex surfaces facing the reduction side. The seventh lens element L 7 has a negative meniscus shape with the convex surfaces facing the reduction side. The eighth lens element L 8 has a positive meniscus shape with the convex surfaces facing the reduction side. The ninth lens element L 9 has a positive meniscus shape with the convex surfaces facing the reduction side. The 10th lens element L 10 has a positive meniscus shape with the convex surfaces facing the reduction side.

The rear group Opr of the magnification optical system Op is constituted of the 11th lens element L 11 to the 12th lens element L 12 in this order from the magnification side to the reduction side. The 11th lens element L 1 l has a biconvex shape. The 12th lens element L 12 has a positive meniscus shape with the convex surfaces facing the magnification side.

The relay optical system O 1 is constituted of the 13th lens element L 13 to the 25th lens element L 25 in order from the magnification side to the reduction side. The 13th lens element L 13 has a biconcave shape. The 14th lens element L 14 has a biconcave shape. The 15th lens element L 15 has a positive meniscus shape with the convex surfaces facing the reduction side. The 16th lens element L 16 has a positive meniscus shape with the convex surfaces facing the reduction side. The 17th lens element L 17 has a negative meniscus shape with the convex surfaces facing the reduction side. The 18th lens element L 18 has a biconvex shape. The 19th lens element L 19 has a biconvex shape. The 20th lens element L 20 has a biconcave shape. The 21st lens element L 21 has a biconcave shape. The 22nd lens element L 22 has a biconvex shape. The 23rd lens element L 23 has a biconvex shape. The 24th lens element L 24 has a negative meniscus shape with the convex surfaces facing the magnification side. The 25th lens element L 25 has a biconvex shape.

By way of example, the first lens element L 1 corresponds to the first lens element recited in claims.

›Example 5

As shown in FIGS. 13 and 14 A- 14 C , the zoom lens system according to example 5 includes the magnification optical system Op and the relay optical system O 1 . The magnification optical system Op is constituted of the first lens element L 1 to the 12th lens element L 12 . The magnification optical system Op includes the front group Opf and the rear group Opr.

The front group Opf of the magnification optical system Op is constituted of the first lens element L 1 to the 10th lens element L 10 in order from the magnification side to the reduction side. The first lens element L 1 has a negative meniscus shape with the convex surfaces facing the magnification side. The second lens element L 2 has a negative meniscus shape with the convex surfaces facing the magnification side. The third lens element L 3 has a negative meniscus shape with the convex surfaces facing the magnification side. The fourth lens element L 4 has a positive meniscus shape with the convex surfaces facing the reduction side. The fifth lens element L 5 has a negative meniscus shape with the convex surfaces facing the reduction side. The sixth lens element L 6 has a positive meniscus shape with the convex surfaces facing the reduction side. The seventh lens element L 7 has a biconcave shape. The eighth lens element L 8 has a biconvex shape. The ninth lens element L 9 has a positive meniscus shape with the convex surfaces facing the reduction side. The 10th lens element L 10 has a biconvex shape.

The relay optical system O 1 is constituted of the 13th lens element L 13 to the 25th lens element L 25 in order from the magnification side to the reduction side. The 13th lens element L 13 has a negative meniscus shape with the convex surfaces facing the magnification side. The 14th lens element L 14 has a biconcave shape. The 15th lens element L 15 has a positive meniscus shape with the convex surfaces facing the reduction side. The 16th lens element L 16 has a biconvex shape. The 17th lens element L 17 has a negative meniscus shape with the convex surfaces facing the reduction side. The 18th lens element L 18 has a biconvex shape. The 19th lens element L 19 has a biconvex shape. The 20th lens element L 20 has a biconcave shape. The 21st lens element L 21 has a biconcave shape. The 22nd lens element L 22 has a biconvex shape. The 23rd lens element L 23 has a biconvex shape. The 24th lens element L 24 has a negative meniscus shape with the convex surfaces facing the magnification side. The 25th lens element L 25 has a biconvex shape.

By way of example, the first lens element L 1 corresponds to the first lens element recited in claims.

›Example 6

As shown in FIGS. 16 and 17 A- 17 C , the zoom lens system according to example 6 includes the magnification optical system Op and the relay optical system O 1 . The magnification optical system Op is constituted of the first lens element L 1 to the 12th lens element L 12 . The magnification optical system Op includes the front group Opf and the rear group Opr.

The front group Opf of the magnification optical system Op is constituted of the first lens element L 1 to the 10th lens element L 10 in order from the magnification side to the reduction side. The first lens element L 1 has a negative meniscus shape with the convex surfaces facing the magnification side. The second lens element L 2 has a negative meniscus shape with the convex surfaces facing the magnification side. The third lens element L 3 has a negative meniscus shape with the convex surfaces facing the magnification side. The fourth lens element L 4 has a negative meniscus shape with the convex surfaces facing the reduction side. The fifth lens element L 5 has a negative meniscus shape with the convex surfaces facing the reduction side. The sixth lens element L 6 has a positive meniscus shape with the convex surfaces facing the reduction side. The seventh lens element L 7 has a negative meniscus shape with the convex surfaces facing the reduction side. The eighth lens element L 8 has a positive meniscus shape with the convex surfaces facing the reduction side. The ninth lens element L 9 has a positive meniscus shape with the convex surfaces facing the reduction side. The 10th lens element L 10 has a biconvex shape.

The relay optical system O 1 is constituted of the 13th lens element L 13 to the 25th lens element L 25 in order from the magnification side to the reduction side. The 13th lens element L 13 has a biconcave shape. The 14th lens element L 14 has a biconcave shape. The 15th lens element L 15 has a positive meniscus shape with the convex surfaces facing the reduction side. The 16th lens element L 16 has a positive meniscus shape with the convex surfaces facing the reduction side. The 17th lens element L 17 has a negative meniscus shape with the convex surfaces facing the reduction side. The 18th lens element L 18 has a biconvex shape. The 19th lens element L 19 has a biconvex shape. The 20th lens element L 20 has a biconcave shape. The 21st lens element L 21 has a biconcave shape. The 22nd lens element L 22 has a biconvex shape. The 23rd lens element L 23 has a biconvex shape. The 24th lens element L 24 has a negative meniscus shape with the convex surfaces facing the magnification side. The 25th lens element L 25 has a biconvex shape.

By way of example, the first lens element L 1 corresponds to the first lens element recited in claims.

›Example 7 · 1 of 6

As shown in FIGS. 19 and 20 A- 20 C , the zoom lens system according to example 7 includes the magnification optical system Op and the relay optical system O 1 . The magnification optical system Op is constituted of the first lens element L 1 to the 12th lens element L 12 . The magnification optical system Op includes the front group Opf and the rear group Opr.

The front group Opf of the magnification optical system Op is constituted of the first lens element L 1 to the 10th lens element L 10 in order from the magnification side to the reduction side. The first lens element L 1 has a negative meniscus shape with the convex surfaces facing the magnification side. The second lens element L 2 has a negative meniscus shape with the convex surfaces facing the magnification side. The third lens element L 3 has a negative meniscus shape with the convex surfaces facing the magnification side. The fourth lens element L 4 has a negative meniscus shape with the convex surfaces facing the reduction side. The fifth lens element L 5 has a negative meniscus shape with the convex surfaces facing the reduction side. The sixth lens element L 6 has a positive meniscus shape with the convex surfaces facing the reduction side. The seventh lens element L 7 has a biconcave shape. The eighth lens element L 8 has a positive meniscus shape with the convex surfaces facing the reduction side. The ninth lens element L 9 has a positive meniscus shape with the convex surfaces facing the reduction side. The 10th lens element L 10 has a biconvex shape.

The relay optical system O 1 is constituted of the 13th lens element L 13 to the 25th lens element L 25 in order from the magnification side to the reduction side. The 13th lens element L 13 has a negative meniscus shape with the convex surfaces facing the magnification side. The 14th lens element L 14 has a biconcave shape. The 15th lens element L 15 has a positive meniscus shape with the convex surfaces facing the reduction side. The 16th lens element L 16 has a positive meniscus shape with the convex surfaces facing the reduction side. The 17th lens element L 17 has a negative meniscus shape with the convex surfaces facing the reduction side. The 18th lens element L 18 has a biconvex shape. The 19th lens element L 19 has a biconvex shape. The 20th lens element L 20 has a biconcave shape. The 21st lens element L 21 has a biconcave shape. The 22nd lens element L 22 has a biconvex shape. The 23rd lens element L 23 has a biconvex shape. The 24th lens element L 24 has a negative meniscus shape with the convex surfaces facing the magnification side. The 25th lens element L 25 has a biconvex shape.

By way of example, the first lens element L 1 corresponds to the first lens element recited in claims.

The zoom lens system according to each of examples 1 to 7 may include not only lens elements having an optical power but also elements having zero or substantially zero optical power, such as mirrors, apertures, masks, cover glasses, filters, prisms, wave plates, and polarizing elements.

Next, conditions which the zoom lens system according to examples 1 to 3 can satisfy are described below. Although a plurality of the conditions are defined for the zoom lens system according to each of the examples, all of these plurality of conditions may be satisfied, or the individual conditions may be satisfied to obtain the corresponding effects.

A zoom lens system according to each of examples 1 to is an optical system internally having an intermediate imaging position that is conjugate to a magnification conjugate point on a magnification side and a reduction conjugate point on a reduction side, respectively, the zoom lens system including:

7<| Ts/fw|< 15 (1)

2<| Tpr/fw|< 7 (2)

where, Ts is the longest air distance, fw is a focal length of the entire optical system at the wide-angle end, and Tpr is a distance from a surface closest to the magnification side of the magnification optical system rear group to the intermediate imaging position.

›Example 7 · 2 of 6

The condition (1) is a conditional expression for defining the relationship between the longest air distance and the focal length of the entire optical system at the wide-angle end. When satisfying the condition (1), the optical system can achieve a wider angle. If falling below the lower limit of the condition (1), the lens of the magnification optical system front group becomes heavier. If exceeding the upper limit of the condition (1), the center of gravity of the entire optical system is moved to the magnification side. The condition (2) is a conditional expression for defining the relationship between the distance between the surface of the magnification optical system rear group on the magnification side to the intermediate imaging position and the focal length of the entire optical system at the wide-angle end. When satisfying the condition (2), the effect of the condition (1) can be exhibited.

In addition to the conditions (1) and (2), more advantageous effects can be obtained by further satisfying at least one of the following conditions (1A) and (2A):

7<| Ts/fw|< 12 (1A)

4<| Tpr/fw|< 6 (2A).

Further, the zoom lens system according to each of examples 1 to 7 may satisfy the following condition (3):

0.8< Tp/Tr< 1.3 (3)

where, Tp is a distance from a surface closest to the magnification side of the magnification optical system to the intermediate imaging position, and Tr is a distance from the intermediate imaging position at the wide-angle end to a surface closest to the reduction side of the relay optical system.

The condition (3) is a conditional expression for defining the relationship between the distance from the surface closest to the magnification side of the magnification optical system to the intermediate imaging position and the distance from the intermediate imaging position at the wide-angle end to the surface closest to the reduction side of the relay optical system. If exceeding the upper limit of the condition (3), the field curvature becomes difficult to be corrected. If falling below the lower limit of the condition (3), the center of gravity is moved to the magnification side.

The zoom lens system according to each of examples 1 to 7 may satisfy the following condition (4):

0.3< fp/fr< 1.1 (4)

where, fp is a focal length of the magnification optical system, and fr is a focal length of the relay optical system at the wide-angle end.

The condition (4) is a conditional expression for defining the relationship between the composite focal lengths of the magnification optical system and the relay optical system. When satisfying this, an optical system having a wide angle and a small lens diameter can be realized. If falling below the lower limit value of the condition (4), the effective diameter of the positive power lens element which is located on the magnification side with respect to the intermediate imaging position and closest to the intermediate imaging position becomes too large, and the lens becomes heavier. On the other hand, if exceeding the upper limit value, the effective diameter of the lens located closest to the magnification side becomes too large, and the lens becomes heavier.

The zoom lens system according to each of examples 1 to 7 may satisfy the following condition (5):

2<| fpr/fw|< 10 (5)

where, fpr is a focal length of the magnification optical system rear group.

The condition (5) is a conditional expression for defining the relationship between the focal length of the magnification optical system rear group and the focal length of the entire optical system at the wide-angle end. If exceeding the upper limit of the condition (5), the diameter of the magnification optical system rear group becomes too large, and the lens becomes heavier. If falling below the lower limit of the condition (5), the diameter of the magnification optical system front group becomes too large, and the lens becomes heavier.

In addition to the condition (5), more advantageous effects can be obtained by further satisfying the following condition (5A):

| fpr/fw|< 9 (5A).

The zoom lens system according to each of examples 1 to 7 may satisfy the following condition (6):

2<| fpf/fw|< 5 (6)

where, fpf is a focal length of the magnification optical system front group.

The condition (6) is a conditional expression for defining the relationship between the focal length of the magnification optical system front group and the focal length of the entire optical system at the wide-angle end. If exceeding the upper limit of the condition (6), the diameter of the magnification optical system front group becomes too large, and the lens becomes heavier. If falling below the lower limit of the condition (6), the diameter of the magnification optical system rear group becomes too large, and the lens becomes heavier.

In addition to the condition (6), more advantageous effects can be obtained by further satisfying the following condition (6A):

| fpf/fw|< 4 (6A).

Further, in the zoom lens system according to each of examples 1 to 7, during zooming the magnification optical system may be fixed, and a part or all of the lens elements in the relay optical system may be displaced along the optical axis.

According to this configuration, arrangement of a zoom mechanism closer to the reduction side with respect to the intermediate imaging position allows a zoom operation mechanism, such as, cam, motor, to be implemented on the reduction side. Therefore, the center of gravity of a lens barrel can be brought closer to the reduction side.

Further, in the zoom lens system according to each of examples 1 to 7, the relay optical system may include, in order from the magnification side to the reduction side, a first lens group having a negative power, a second lens group having a positive power, a third lens group having the negative power, and a fourth lens group having the positive power, and

during zooming the first lens group and the third lens group may be fixed, and the second lens group and the fourth lens group may be displaced along the optical axis.

›Example 7 · 3 of 6

According to this configuration, the lens diameter of the relay optical system can be made small while high optical performance is maintained over the entire zoom range, and the weight of the relay optical system can be reduced.

Further, the zoom lens system according to each of examples 1 to 7 may satisfy the following condition (7):

3<| T 12 /fw|< 10 (7)

where, T12 is an air distance between the first lens group and the second lens group at the wide-angle end.

The condition (7) is a conditional expression for defining the relationship between the air distance between the first lens group and the second lens group and the focal length of the entire optical system at the wide-angle end. If exceeding the upper limit of the condition (7), the diameter of the magnification optical system rear group becomes too large, and the lens becomes heavier. If falling below the lower limit of the condition (7), the field curvature becomes difficult to be corrected.

In addition to the condition (7), more advantageous effects can be obtained by further satisfying the following condition (7A):

4<| T 12 /fw| (7A).

Further, the zoom lens system according to each of examples 1 to 7 may satisfy the following condition (8):

10 <fr 1 /fw< 30 (8)

where, fr1 is a focal length of the first lens group.

The condition (8) is a conditional expression for defining the relationship between the focal length of the first lens group and the focal length of the entire optical system at the wide-angle end. If exceeding the upper limit of the condition (8), the diameter of the first lens group becomes too large, and the lens becomes heavier. If falling below the lower limit of the condition (8), the diameter of the magnification optical system rear group becomes too large, and the lens becomes heavier.

In addition to the condition (8), more advantageous effects can be obtained by further satisfying the following condition (8A):

14 <fr 1 /fw< 26 (8A).

Further, the zoom lens system according to each of examples 1 to 7 may satisfy the following condition (9):

5 <|fr 2 /fw|< 30 (9)

where, fr2 is a focal length of the second lens group.

The condition (9) is a conditional expression for defining the relationship between the focal length of the second lens group and the focal length of the entire optical system at the wide-angle end. If exceeding the upper limit of the condition (9), variation of an axial chromatic aberration increases during zooming, and the axial chromatic aberration becomes difficult to be satisfactorily corrected in the entire zoom range. If falling below the lower limit of the condition (9), sensitivity of an aberration relative to eccentricity increases, and manufacturing becomes difficult.

In addition to the condition (9), more advantageous effects can be obtained by further satisfying the following condition (9A):

11 <|fr 2 /fw|< 15 (9A).

Further, the zoom lens system according to each of examples 1 to 7 may satisfy the following condition (10):

5 <fr 3 /fw< 50 (10)

where, fr3 is a focal length of the third lens group.

The condition (10) is a conditional expression for defining the relationship between the focal length of the third lens group and the focal length of the entire optical system at the wide-angle end. If exceeding the upper limit of the condition (10), the diameter of the third lens group becomes too large, and the lens becomes heavier. If falling below the lower limit of the condition (10), the diameter of the fourth lens group becomes too large, and the lens becomes heavier.

In addition to the condition (10), more advantageous effects can be obtained by further satisfying the following condition (10A)):

10 <fr 3 /fw< 15 (10A).

Further, the zoom lens system according to each of examples 1 to 7 may satisfy the following condition (11):

3 <|fr 4 /fw|< 9 (11)

where, fr4 is a focal length of the fourth lens group.

The condition (11) is a conditional expression for defining the relationship between the focal length of the third lens group and the focal length of the entire optical system at the wide-angle end. If exceeding the upper limit of the condition (11), variation of the field curvature increases during zooming, and the field curvature becomes difficult to be satisfactorily corrected in the entire zoom range. If falling below the lower limit of the condition (11), sensitivity of the aberration relative to eccentricity increases, and manufacturing becomes difficult.

In addition to the condition (11), more advantageous effects can be obtained by further satisfying the following condition (11A):

6 <|fr 4 /fw|< 7 (11A).

Further, in the zoom lens system according to each of examples 1 to 7, a first lens element and a second lens element may be arranged in order from the magnification side to the reduction side of the magnification optical system, and the zoom lens system may satisfy the following condition (12):

1 <|T 1 /fw|< 6 (12)

where, T1 is an air distance between the first lens element and the second lens element.

The condition (12) is a conditional expression that defines the relationship between the air distance between the first lens element and the second lens element and the focal length of the entire system at the wide-angle end. If exceeding the upper limit of the condition (12), the first lens element becomes too heavier, and the weight of the entire optical system increases. If falling below the lower limit of the condition (12), the second lens element becomes too heavier, and the weight of the entire optical system increases.

In addition to the condition (12), more advantageous effects can be obtained by further satisfying the following condition (12A):

| T 1 /fw|< 4 (12A).

Further, the zoom lens system according to each of examples 1 to 7 may satisfy the following condition (13):

1 <|Tm/fw|< 9 (13)

where, Tm is a distance from a surface on the reduction side of the magnification optical system to a surface on the magnification side of the relay optical system.

The condition (13) is a conditional expression for defining the relationship between the distance from the surface on the reduction side of the magnification optical system to the surface on the magnification side of the relay optical system and the focal length of the entire optical system at the wide-angle end. If exceeding the upper limit of the condition (13), the entire length of the optical system becomes longer, and the center of gravity is moved to the magnification side. If falling below the lower limit of the condition (13), in case foreign matters adhere to the lens in the vicinity of the intermediate imaging, they become noticeable in the image.

›Example 7 · 4 of 6

In addition to the condition (13), more advantageous effects can be obtained by further satisfying the following condition (13A):

2 <|Tm/fw|< 5 (13A).

Further, in the zoom lens system according to each of examples 1 to 7, the first lens element may be arranged closest to the magnification side of the magnification optical system, and the first lens element may have a first lens magnification side aspherical surface facing the magnification side and a first lens reduction side aspherical surface facing the reduction side, and the first lens magnification side surface and the first lens reduction side surface may satisfy the following condition (14) within a range above zero (r>0) to an effective diameter:

dZ ( r )/ dr> 0 (14)

where, r is a distance (r>0) from a vertex of a surface as measured along a plane perpendicular to the optical axis of the optical system, and

Z(r) is an amount of sag of the surface (assuming that Z=0 at the vertex (r=0), where Z has a sign + for reduction side displacement with respect to the vertex, and a sign − for magnification side displacement).

The condition (14) is a conditional expression for defining that the first derivative dZ(r)/dr of the amount of sag Z(r) of the surface is positive. When satisfying the condition (14), even when local heat is generated in the first lens element, a change in shape due to thermal expansion take places likewise in both the magnification side surface and the reduction side surface of the first lens element. As a result, the occurrence of field curvature and astigmatism can be suppressed.

In addition, in the zoom lens system according to each of examples 1 to 7, the first lens element may be made of synthetic resin.

According to this configuration, the first lens element is easily made large in diameter, and the weight of the lens can be reduced by using the synthetic resin.

In the zoom lens system according to each of examples 1 to 7, all the lens elements that satisfy the condition (15) among the plurality of lens elements may satisfy the condition (16), and one lens element among the plurality of lens elements may not satisfy both of the conditions (15) and (16):

| ym /( fw ·tan(ω m ))|<3.0 (15)

Tg> 300° C. (16)

where, ωm is a maximum half angle of view at the wide-angle end, ym is a height at the telephoto end at which the most off-axis main ray passes through the lens surface, and Tg is a glass transition point of lens material.

The condition (15) is a conditional expression for defining the relationship among the height at the telephoto end at which the most off-axis main ray passes through the lens surface, the focal length of the entire optical system at the wide-angle end, and the maximum half angle of view at the wide-angle end. The condition (16) is a conditional expression for defining the glass transition point of the lens material. When satisfying both of the conditions (15) and (16), deterioration of the lens can be prevented when high intensity light passes through the lens. Note that ym is calculated as a lower one out of a height of the light passing through the surface on the magnification side and a height of the light passing through the surface on the reduction side of the lens.

Further, the zoom lens system according to each of examples 1 to 7 may satisfy the following conditional expression (17):

ω m> 65° (17)

where, ωm is a maximum half angle of view at the wide-angle end.

The condition (17) is a conditional expression for defining the maximum half angle of view at the wide-angle end. When satisfying the condition (17), a working distance can be shortened.

As described above, some examples have been described to exemplify the technology disclosed in the present application. The technology of the present disclosure, however, is not limited only to these examples, but also can be applied to other embodiments appropriately devised through modification, substitution, addition, omission and so on.

Hereinafter, numerical examples of the zoom lens system according to examples 1 to 7 are described. In each of the numerical examples, in the table, the unit of length is all “mm”, and the unit of angle of view is all “°” (degree). Further, in each of the numerical examples, r is a radius of curvature, d is a surface interval, nd is a refractive index for d line, and vd is an Abbe number for d line. Further, in each of the numerical examples, a surface marked with “*” is aspherical, and the aspherical shape is defined by the following formula.

Numerical Example 1

Regarding the zoom lens system of numerical example 1 (corresponding to example 1), Table 1 shows surface data, Table 2 shows various data, Table 3 shows single lens data, and Table 4 shows zoom lens group data (unit: mm).

Aspherical Data

1st Surface

K=0.00000E+00, A3=−7.25014E-06, A4=−1.15220E-06, A5=2.72823E-08, A6=−4.98172E-11, A7=−3.06439E-12, A8=5.81613E-15, A9=4.07487E-16, A10=−2.69504E-18

2nd Surface

K=−1.22715E+00, A3=1.40108E-05, A4=−2.62157E-06, A5=7.38521E-09, A6=2.80400E-10, A7=2.43598E-14, A8=−1.40378E-14, A9=−2.03884E-16, A10=1.80622E-18

9th Surface

K=0.00000E+00, A3=0.00000E+00, A4=2.14919E-05, A5=0.00000E+00, A6=2.07809E-07, A7=0.00000E+00, A8=−7.30054E-10, A9=0.00000E+00, A10=8.85358E-13

10th Surface

K=0.00000E+00, A3=0.00000E+00, A4=2.81203E-05, A5=0.00000E+00, A6=1.62721E-07, A7=0.00000E+00, A8=0.00000E+00, A9=0.00000E+00, A10=0.00000E+00

Numerical Example 2

Regarding the zoom lens system of numerical example 2 (corresponding to example 2), Table 5 shows surface data, Table 6 shows various data, Table 7 shows single lens data, and Table 8 shows zoom lens group data (unit: mm).

Aspherical Data

1st Surface

K=0.00000E+00, A3=−2.65067E-06, A4=4.62668E-07, A5=1.02356E-09, A6=−5.81330E-11, A7=8.20273E-14, A8=6.76604E-15, A9=2.18048E-17, A10=−5.71783E-19

2nd Surface

K=−9.55907E-01, A3=0.00000E+00, A4=−1.80425E-06, A5=0.00000E+00, A6=9.34430E-11, A7=0.00000E+00, A8=9.19265E-15, A9=0.00000E+00, A10=−1.18438E-18

9th Surface

K=0.00000E+00, A3=0.00000E+00, A4=4.18656E-06, A5=0.00000E+00, A6=4.74295E-08, A7=0.00000E+00, A8=−1.07013E-09, A9=0.00000E+00, A10=0.00000E+00

›Example 7 · 5 of 6

10th Surface

K=0.00000E+00, A3=0.00000E+00, A4=2.35037E-05, A5=0.00000E+00, A6=7.58692E-08, A7=0.00000E+00, A8=−4.25680E-10, A9=0.00000E+00, A10=0.00000E+00

33rd Surface

K=0.00000E+00, A3=0.00000E+00, A4=9.60708E-06, A5=0.00000E+00, A6=−8.51152E-09, A7=0.00000E+00, A8=4.75793E-12, A9=0.00000E+00, A10=0.00000E+00

34th Surface

K=0.00000E+00, A3=0.00000E+00, A4=9.30721E-06, A5=0.00000E+00, A6=−5.66264E-09, A7=0.00000E+00, A8=2.36850E-12, A9=0.00000E+00, A10=0.00000E+00

Numerical Example 3

Regarding the zoom lens system of numerical example 3 (corresponding to example 3), Table 9 shows surface data, Table 10 shows various data, Table 11 shows single lens data, and Table 12 shows zoom lens group data (unit: mm).

Aspherical Data

1st Surface

K=0.00000E+00, A3=−4.98082E-05, A4=1.02415E-06, A5=−2.94689E-08, A6=7.04235E-10, A7=−6.53517E-12, A8=−1.32511E-14, A9=4.97035E-16, A10=−1.16266E-18, A11=1.10076E-22, A12=−1.04222E-23, A13=−7.34121E-26, A14=−1.19521E-26, A15=5.84967E-29, A16=−1.36553E-32, A17=−1.81844E-33, A18=−1.06538E-35, A19=−2.13620E-37, A20=−9.95976E-39

2nd Surface

K=−9.54170E-01, A3=−1.48327E-05, A4=−2.41212E-06, A5=−5.68248E-10, A6=1.08199E-10, A7=−3.03274E-13, A8=3.45630E-15, A9=9.09825E-17, A10=4.23242E-18, A11=−4.76060E-21, A12=−5.81989E-22, A13=−8.46992E-24, A14=8.97671E-26, A15=−4.55046E-28, A16=−3.81800E-30, A17=1.48597E-32, A18=1.41251E-33, A19=3.80980E-35, A20=−4.85676E-37

Numerical Example 4

Regarding the zoom lens system of numerical example 4 (corresponding to example 4), Table 13 shows surface data, Table 14 shows various data, Table 15 shows single lens data, and Table 16 shows zoom lens group data (unit: mm).

Aspherical Data

1st Surface

K=0.00000E+00, A3=−5.32341E-06, A4=−1.08236E-06, A5=2.61031E-08, A6=−4.27853E-11, A7=−3.00834E-12, A8=5.23078E-15, A9=4.08999E-16, A10=−2.64786E-18

2nd Surface

K=−1.22711E+00, A3=1.51511E-05, A4=−2.64143E-06, A5=7.26941E-09, A6=2.79585E-10, A7=3.15970E-14, A8=−1.39833E-14, A9=−1.99424E-16, A10=1.77284E-18

9th Surface

K=0.00000E+00, A3=0.00000E+00, A4=1.92717E-05, A5=0.00000E+00, A6=1.99778E-07, A7=0.00000E+00, A8=−7.68502E-10, A9=0.00000E+00, A10=−1.41298E-13

10th Surface

K=0.00000E+00, A3=0.00000E+00, A4=2.60433E-05, A5=0.00000E+00, A6=1.52935E-07, A7=0.00000E+00, A8=0.00000E+00, A9=0.00000E+00, A10=0.00000E+00

Numerical Example 5

Regarding the zoom lens system of numerical example 5 (corresponding to example 5), Table 17 shows surface data, Table 18 shows various data, Table 19 shows single lens data, and Table 20 shows zoom lens group data (unit: mm).

Aspherical Data

1st Surface

K=0.00000E+00, A3=−1.80686E-05, A4=−1.24260E-06, A5=2.82728E-08, A6=−4.68886E-11, A7=−3.14281E-12, A8=3.69704E-15, A9=4.05487E-16, A10=−2.70992E-18

2nd Surface

K=−1.29848E+00, A3=9.60558E-06, A4=−2.58551E-06, A5=8.15356E-09, A6=2.89291E-10, A7=7.31407E-14, A8=−1.40654E-14, A9=−2.05740E-16, A10=1.87867E-18

9th Surface

K=0.00000E+00, A3=0.00000E+00, A4=2.17129E-05, A5=0.00000E+00, A6=2.20039E-07, A7=0.00000E+00, A8=−6.23863E-10, A9=0.00000E+00, A10=1.23212E-12

10th Surface

K=0.00000E+00, A3=0.00000E+00, A4=2.79313E-05, A5=0.00000E+00, A6=1.44206E-07, A7=0.00000E+00, A8=0.00000E+00, A9=0.00000E+00, A10=0.00000E+00

Numerical Example 6

Regarding the zoom lens system of numerical example 6 (corresponding to example 6), Table 91 shows surface data, Table 22 shows various data, Table 23 shows single lens data, and Table 24 shows zoom lens group data (unit: mm).

Aspherical Data

1st Surface

K=0.00000E+00, A3=−1.74067E-05, A4=−8.55706E-07, A5=2.47548E-08, A6=−5.71120E-11, A7=−2.95249E-12, A8=6.30469E-15, A9=4.04186E-16, A10=−2.73602E-18

2nd Surface

K=−1.29979E+00, A3=3.56842E-06, A4=−2.46793E-06, A5=9.34818E-09, A6=2.89223E-10, A7=−1.38298E-13, A8=−1.85781E-14, A9=−2.48923E-16, A10=2.68573E-18

9th Surface

K=0.00000E+00, A3=0.00000E+00, A4=2.51303E-05, A5=0.00000E+00, A6=1.94136E-07, A7=0.00000E+00, A8=−4.58227E-10, A9=0.00000E+00, A10=4.69317E-13

10th Surface

K=0.00000E+00, A3=0.00000E+00, A4=2.81131E-05, A5=0.00000E+00, A6=1.45179E-07, A7=0.00000E+00, A8=0.00000E+00, A9=0.00000E+00, A10=0.00000E+00

Numerical Example 7

Regarding the zoom lens system of numerical example 7 (corresponding to example 7), Table 25 shows surface data,

Table 26 shows various data, Table 27 shows single lens data, and Table 28 shows zoom lens group data (unit: mm).

Aspherical Data

1st Surface

K=0.00000E+00, A3=−1.52651E-05, A4=−9.94232E-07, A5=2.44429E-08, A6=−1.95730E-11, A7=−3.08842E-12, A8=2.25161E-15, A9=4.13973E-16, A10=−2.55437E-18

2nd Surface

K=−1.34729E+00, A3=9.87687E-06, A4=−2.47222E-06, A5=9.33782E-09, A6=2.90162E-10, A7=−1.04007E-13, A8=−1.82010E-14, A9=−2.48249E-16, A10=2.59959E-18

9th Surface

K=0.00000E+00, A3=0.00000E+00, A4=2.53409E-05, A5=0.00000E+00, A6=2.16366E-07, A7=0.00000E+00, A8=−3.24181E-10, A9=0.00000E+00, A10=1.24182E-13

10th Surface

K=0.00000E+00, A3=0.00000E+00, A4=2.70872E-05, A5=0.00000E+00, A6=1.50922E-07, A7=0.00000E+00, A8=0.00000E+00, A9=0.00000E+00, A10=0.00000E+00

Table 29 below shows the corresponding values of the respective conditions (1) to (17) in the respective numerical examples.

Table 30 below shows values of the variables of the respective conditions (1) to (17) in the respective numerical examples.

Tables 31A-32B and 32A-32B below show values of |ym/(fw·tan(ωm))| in the condition (15) and Tg in the condition (16) in the respective numerical examples. Note that the lens material, Z330R, is the product name of cyclo-olefin polymers (COP) (ZEON). The lens element L 1 can be also made of various synthetic resins, resulting in a lightweight lens. The remaining lens elements L 2 to L 26 can be also made of various synthetic resins, resulting in lightweight lenses.

Second Embodiment

Hereinafter, a second embodiment of the present disclosure is described with reference to FIG. 22 . FIG. 22 is a block diagram showing an example of the image projection apparatus according to the present disclosure. The image projection apparatus 100 includes such an optical system 1 as disclosed in the first embodiment, an image forming element 101 , a light source 102 , a control unit 110 , and others. The image forming element 101 is constituted of, for example, liquid crystal or DMD, for generating an image to be projected through the optical system 1 onto a screen SR. The light source 102 is constituted of such as a light emitting diode (LED) or a laser, and supplies light to the image forming element 101 . The control unit 110 is constituted of, for example, central processing unit (CPU) or micro-processing unit (MPU), for controlling the entire apparatus and respective components. The optical system 1 may be configured as an interchangeable lens that can be detachably attached to the image projection apparatus 100 . In this case, an apparatus in which the optical system 1 is removed from the image projection apparatus 100 is an example of a main body apparatus.

›Example 7 · 6 of 6

The image projection apparatus 100 described above can realize a wide-angle zoom function while reducing a moment acting on the center of gravity and mitigating thermal effect by employing the optical system 1 according to the first embodiment.

Third Embodiment

Hereinafter, a third embodiment of the present disclosure is described with reference to FIG. 23 . FIG. 23 is a block diagram showing an example of the imaging apparatus according to the present disclosure. The imaging apparatus 200 includes such an optical system 1 as disclosed in the first embodiment, an imaging element 201 , a control unit 210 , and others. The imaging element 201 is constituted of, for example, charge coupled device (CCD) image sensor or complementary metal oxide semiconductor (CMOS) image sensor, for receiving an optical image of an object OBJ formed by the optical system 1 to convert the image into an electrical image signal. The control unit 110 is constituted of, for example, CPU or MPU, for controlling the entire apparatus and respective components. The optical system 1 may be configured as an interchangeable lens that can be detachably attached to the imaging apparatus 200 . In this case, an apparatus in which the optical system 1 is removed from the imaging apparatus 200 is an example of a main body apparatus.

The imaging apparatus 200 described above can realize a wide-angle zoom function while reducing a moment acting on the center of gravity and mitigating thermal effect by employing the optical system 1 according to the first embodiment.

As described above, the embodiments have been described to disclose the technology in the present disclosure. To that end, the accompanying drawings and detailed description are provided.

Therefore, among the components described in the accompanying drawings and the detailed description, not only the components that are essential for solving the problem, but also the components that are not essential for solving the problem may also be included in order to exemplify the above-described technology. Therefore, it should not be directly appreciated that the above non-essential components are essential based on the fact that the non-essential components are described in the accompanying drawings and the detailed description.

Further, the above-described embodiments have been described to exemplify the technology in the present disclosure. Thus, various modification, substitution, addition, omission and so on can be made within the scope of the claims or equivalents thereof.

›INDUSTRIAL APPLICABILITY

The present disclosure can be applied to image projection apparatuses such as projectors and head-up displays, and imaging apparatuses such as digital still cameras, digital video cameras, surveillance cameras in surveillance systems, web cameras, and onboard cameras. In particular, the present disclosure can be applied to optical systems that require a high image quality, such as projectors, digital still camera systems, and digital video camera systems.

›Tables in the description — 28

where, Z is a distance from a point located on an aspherical surface at a height “h” from the optical axis, to the tangent plane of the aspherical vertex, h is a height from the optical axis, r is a radius of curvature of the vertex, K is a cone constant, and An is a nth-order aspherical coefficient.

(

)

⁢

(

)

∑

⁢

[

Mathematical

⁢

Formula

⁢

]

TABLE 2 — Various data

Zoom ratio	1.07128
	WIDE-ANGLE	INTERMEDIATE	TELEPHOTO
Focal length	−7.2355	−7.4717	−7.7512
F number	−1.91298	−1.91566	−1.91968
Angle of view	−66.8135	−66.1719	−65.4059
Image height	17.2650	17.2650	17.2650
Total length of lens	520.0129	520.0218	520.0245
BF	1.01329	1.02242	1.02517
d30	64.3935	61.5954	58.4105
d36	2.0000	4.7981	7.9829
d45	12.4726	12.3440	12.1423
d51	15.3200	15.4484	15.6501
Position of	42.2840	42.2972	42.3159
entrance pupil
Position of	−595.1149	−576.1453	−548.7901
exit pupil
Position of front	34.9607	34.7287	34.4554
principal point
Position of rear	527.2011	527.4432	527.7214
principal point

TABLE 3 — Single lens data

Lens element	First surface	Focal length
1	1	−95.5628
2	3	−154.0331
3	5	−64.1256
4	7	−459.4756
5	9	−1814.3228
6	11	39.5198
7	13	−27.5009
8	15	68.3037
9	17	173.6739
10	19	131.9648
11	21	118.2505
12	23	126.3105
13	25	−57.4536
14	27	−95.2714
15	29	84.2276
16	31	74.3399
17	33	−130.0626
18	35	168.0277
19	37	41.5307
20	40	−31.9830
21	42	−31.1794
22	44	55.3204
23	46	74.2297
24	48	−358.4389
25	50	79.7441

TABLE 4 — Zoom lens group data

				Position	Position
				of front	of rear
	First	Focal	Total	principal	principal
Group	surface	length	length	point	point
1	1	17.89892	299.08240	61.92894	188.87067
2	31	88.42608	19.28940	9.02057	12.67491
3	37	−84.47818	31.76120	30.16528	30.25589
4	46	47.05259	32.93050	10.59383	16.63543
Zoom lens group magnification
	First	WIDE-	INTER-
Group	surface	ANGLE	MEDIATE	TELEPHOTO
1	1	−0.01613	−0.01613	−0.01613
2	31	−1.14821	−1.19150	−1.24493
3	37	−1.26654	−1.24728	−1.21956
4	46	−0.27843	−0.28135	−0.28570

TABLE 6 — Various data

Zoom ratio	1.07524
	WIDE-ANGLE	INTERMEDIATE	TELEPHOTO
Focal length	−7.2781	−7.5294	−7.8257
F number	−1.89960	−1.90067	−1.90235
Angle of view	−66.7419	−66.1476	−65.4354
Image height	17.2650	17.2650	17.2650
Total length of lens	520.0163	520.0156	520.0152
BF	1.01640	1.01584	1.01552
d30	38.9837	35.3568	31.2138
d36	2.0000	5.6269	9.7698
d45	6.2936	6.2335	6.1191
d51	15.3200	15.3800	15.4944
Position of	40.7256	40.7551	40.7942
entrance pupil
Position of	−616.7026	−607.9230	−591.9016
exit pupil
Position of front	33.3618	33.1326	32.8652
principal point
Position of rear	527.2465	527.4938	527.7856
principal point

TABLE 7 — Single lens data

Lens element	First surface	Focal length
1	1	−97.0535
2	3	−75.7737
3	5	−72.5965
4	7	197.9836
5	9	835.3507
6	11	48.4926
7	13	−27.3309
8	15	61.4452
9	17	141.1827
10	19	141.2367
11	21	108.0110
12	23	104.7466
13	25	−43.4262
14	27	−57.1531
15	29	63.3946
16	31	113.4344
17	33	−50.5350
18	35	53.0458
19	37	51.4808
20	40	−40.1428
21	42	−37.0201
22	44	59.4941
23	46	79.1774
24	48	−182.6283
25	50	68.7848

TABLE 8 — Zoom lens group data

				Position	Position
				of front	of rear
	First	Focal	Total	principal	principal
Group	surface	length	length	point	point
1	1	20.36658	281.39930	62.67798	133.51296
2	31	106.43172	61.77500	41.99245	33.45401
3	37	−103.98710	39.31880	29.38709	30.25682
4	46	49.83733	32.15950	10.71081	17.31236
Zoom lens group magnification
	First	WIDE-	INTER-
Group	surface	ANGLE	MEDIATE	TELEPHOTO
1	1	−0.01838	−0.01838	−0.01838
2	31	−1.04663	−1.08534	−1.13322
3	37	−1.92102	−1.90368	−1.87104
4	46	−0.17801	−0.17920	−0.18149

TABLE 10 — Various data

Zoom ratio	1.07159
	WIDE-	INTER-
	ANGLE	MEDIATE	TELEPHOTO
Focal length	−7.2461	−7.4838	−7.7648
F number	−1.97041	−1.97181	−1.97429
Angle of view	−66.7864	−66.1701	−65.4248
Image height	17.2650	17.2650	17.2650
Total length of lens	520.0186	520.0315	520.0365
BF	1.01858	1.03157	1.03656
d32	34.3954	31.8072	28.8643
d38	2.0000	4.5882	7.5311
d47	11.6892	11.6283	11.4986
d53	15.3200	15.3808	15.5105
Position of	41.5035	41.5161	41.5337
entrance pupil
Position of	−3602.6235	−3265.6740	−2723.7680
exit pupil
Position of front	34.2428	34.0151	33.7467
principal point
Position of rear	527.2172	527.4647	527.7469
principal point

TABLE 11 — Single lens data

Lens element	First surface	Focal length
1	1	−92.0424
2	3	−110.5981
3	5	−60.5692
4	7	−118.4160
5	9	48.1403
6	11	−29.2058
7	13	41.5565
8	15	−39.3391
9	17	74.5917
10	19	106.8222
11	21	105.0609
12	23	131.6545
13	25	127.9993
14	27	−67.7935
15	29	−140.8095
16	31	88.1681
17	33	−208.6590
18	35	115.8747
19	37	99.4996
20	40	40.9024
21	42	−32.6823
22	44	−27.8176
23	46	52.1803
24	48	73.3900
25	50	−229.6827
26	52	71.4189

TABLE 12 — Zoom lens group data

				Position	Position
				of front	of rear
	First	Focal	Total	principal	principal
Group	surface	length	length	point	point
1	1	16.36167	298.83590	59.39221	196.90868
2	33	80.54203	50.24160	37.19334	37.42587
3	39	−74.04702	32.29930	27.69110	28.51657
4	48	45.95013	32.46860	9.73608	17.61383
Zoom lens group magnification
	First	WIDE-	INTER-
Group	surface	ANGLE	MEDIATE	TELEPHOTO
1	1	−0.01476	−0.01476	−0.01476
2	33	−1.05462	−1.09161	−1.13696
3	39	−1.51335	−1.50134	−1.48004
4	48	−0.27787	−0.27948	−0.28241

TABLE 14 — Various data

Zoom ratio	1.07110
	WIDE-	INTER-
	ANGLE	MEDIATE	TELEPHOTO
Focal length	−7.2477	−7.4838	−7.7630
F number	−1.91302	−1.91539	−1.91898
Angle of view	−66.7797	−66.1429	−65.3812
Image height	17.2650	17.2650	17.2650
Total length of lens	520.0143	520.0225	520.0253
BF	1.01429	1.02263	1.02545
d30	70.7792	68.0418	64.9273
d36	2.0407	4.7781	7.8926
d45	12.4233	12.3107	12.1307
d51	15.3200	15.4325	15.6125
Position of	41.8940	41.9048	41.9207
entrance pupil
Position of	−595.3865	−578.5443	−553.5762
exit pupil
Position of front	34.5582	34.3244	34.0490
principal point
Position of rear	527.2145	527.4558	527.7340
principal point

TABLE 15 — Single lens data

Lens element	First surface	Focal length
1	1	−93.9052
2	3	−193.1403
3	5	−58.5935
4	7	−633.6045
5	9	1928.6388
6	11	37.8786
7	13	−25.9598
8	15	69.6014
9	17	175.0808
10	19	143.0474
11	21	122.0383
12	23	122.1421
13	25	−57.5761
14	27	−88.1486
15	29	77.0151
16	31	76.9559
17	33	−143.0283
18	35	175.0641
19	37	41.7044
20	40	−32.2803
21	42	−31.0355
22	44	55.2271
23	46	73.2885
24	48	−319.0770
25	50	78.5527

TABLE 16 — Zoom lens group data

				Position	Position
				of front	of rear
	First	Focal	Total	principal	principal
Group	surface	length	length	point	point
1	1	18.06918	299.61690	61.80676	194.14445
2	31	86.72560	12.85750	5.51839	9.42898
3	37	−84.26874	31.73240	30.14098	30.24312
4	46	46.86150	32.48000	10.50105	16.64953
Zoom lens group magnification
	First	WIDE-	INTER-
Group	surface	ANGLE	MEDIATE	TELEPHOTO
1	1	−0.01629	−0.01629	−0.01629
2	31	−1.13099	−1.17286	−1.22443
3	37	−1.29779	−1.28017	−1.25429
4	46	−0.27375	−0.27633	−0.28023

TABLE 18 — Various data

Zoom ratio	1.07174
	WIDE-ANGLE	INTERMEDIATE	TELEPHOTO
Focal length	−7.2510	−7.4894	−7.7712
F number	−1.91320	−1.91666	−1.92171
Angle of view	−66.7701	−66.1350	−65.3775
Image height	17.2650	17.2650	17.2650
Total length of lens	520.0113	520.0208	520.0231
BF	1.01163	1.02116	1.02339
d30	49.7749	46.9581	43.7513
d36	2.0000	4.8168	8.0236
d45	12.7087	12.5347	12.2749
d51	15.3200	15.4939	15.7538
Position of	43.3307	43.3465	43.3682
entrance pupil
Position of	−594.6793	−570.5253	−538.0230
exit pupil
Position of front	35.9915	35.7590	35.4849
principal point
Position of rear	527.2149	527.4596	527.7398
principal point

TABLE 19 — Single lens data

Lens element	First surface	Focal length
1	1	−99.4905
2	3	−142.8978
3	5	−70.8149
4	7	1046.7742
5	9	−671.7381
6	11	48.9258
7	13	−31.7277
8	15	61.5319
9	17	209.3991
10	19	137.4705
11	21	109.9108
12	23	108.0791
13	25	−50.3847
14	27	−114.6269
15	29	100.4704
16	31	69.8133
17	33	−119.3380
18	35	168.1546
19	37	41.9344
20	40	−31.8635
21	42	−31.5293
22	44	54.9265
23	46	76.1079
24	48	−425.0804
25	50	81.6652

TABLE 20 — Zoom lens group data

				Position	Position
				of front	of rear
	First	Focal	Total	principal	principal
Group	surface	length	length	point	point
1	1	17.35441	304.33250	62.31153	187.32213
2	31	88.53910	27.12920	13.11252	17.33570
3	37	−86.17768	31.29850	27.74377	28.59629
4	46	48.19888	34.68590	11.58527	16.86729
Zoom lens group magnification
	First	WIDE-	INTER-
Group	surface	ANGLE	MEDIATE	TELEPHOTO
1	1	−0.01563	−0.01563	−0.01563
2	31	−1.20081	−1.24850	−1.30763
3	37	−1.24638	−1.22154	−1.18740
4	46	−0.27960	−0.28341	−0.28884

TABLE 22 — Various data

Zoom ratio	1.07125
	WIDE-	INTER-	TELE-
	ANGLE	MEDIATE	PHOTO
Focal length	−7.2308	−7.4669	−7.7460
F number	−1.91327	−1.91616	−1.92042
Angle of view	−66.8273	−66.1800	−65.4092
Image height	17.2650	17.2650	17.2650
Total length of lens	520.0160	520.0238	520.0243
BF	1.01594	1.02379	1.02437
d30	65.7460	63.0911	60.0737
d36	2.2088	4.8638	7.8811
d45	12.5772	12.4452	12.2397
d51	15.3200	15.4518	15.6573
Position of	41.3329	41.3427	41.3572
entrance pupil
Position of	−595.0768	−575.7057	−548.0188
exit pupil
Position of front	34.0143	33.7791	33.5018
principal point
Position of rear	527.1996	527.4403	527.7161
principal point

TABLE 23 — Single lens data

Lens element	First surface	Focal length
1	1	−93.5797
2	3	−141.1025
3	5	−84.6081
4	7	−521.9422
5	9	−621.9251
6	11	43.2188
7	13	−31.6257
8	15	71.6381
9	17	194.0754
10	19	148.4734
11	21	118.5059
12	23	123.0784
13	25	−51.0437
14	27	−130.2570
15	29	99.9603
16	31	81.4290
17	33	−160.5229
18	35	169.7001
19	37	42.0565
20	40	−32.6314
21	42	−31.3371
22	44	56.6327
23	46	73.1136
24	48	−379.0439
25	50	80.8789

TABLE 24 — Zoom lens group data

				Position	Position
				of front	of rear
	First	Focal	Total	principal	principal
Group	surface	length	length	point	point
1	1	17.56673	306.81810	60.72090	201.50830
2	31	84.37000	10.20150	4.28026	8.19655
3	37	−82.72585	30.67870	28.45123	28.97178
4	46	47.12030	33.69980	11.38892	16.93941
Zoom lens group magnification
	First	WIDE-	INTER-
Group	surface	ANGLE	MEDIATE	TELEPHOTO
1	1	−0.01584	−0.01584	−0.01584
2	31	−1.15384	−1.19731	−1.25088
3	37	−1.24721	−1.22845	−1.20166
4	46	−0.28652	−0.28949	−0.29386

TABLE 26 — Various data

Zoom ratio	1.07093
	WIDE-	INTER-	TELE-
	ANGLE	MEDIATE	PHOTO
Focal length	−7.2295	−7.4654	−7.7423
F number	−1.91923	−1.92230	−1.92676
Angle of view	−66.8342	−66.1810	−65.4093
Image height	17.2650	17.2650	17.2650
Total length of lens	530.0173	530.0245	530.0243
BF	1.01775	1.02488	1.02469
d30	60.9650	58.3362	55.3677
d36	2.1970	4.8259	7.7943
d45	12.6019	12.4620	12.2498
d51	15.3292	15.4690	15.6813
Position of	41.5519	41.5637	41.5806
entrance pupil
Position of	−594.4349	−573.6290	−544.7992
exit pupil
Position of front	34.2345	34.0013	33.7285
principal point
Position of rear	537.1997	537.4395	537.7124
principal point

TABLE 27 — Single lens data

Lens element	First surface	Focal length
1	1	−102.2211
2	3	−254.5452
3	5	−63.8070
4	7	−4410.2316
5	9	−561.2435
6	11	46.4351
7	13	−31.3016
8	15	76.8482
9	17	167.5923
10	19	143.4998
11	21	118.8321
12	23	123.2428
13	25	−55.1573
14	27	−107.6219
15	29	97.5183
16	31	89.4138
17	33	−201.2403
18	35	166.8811
19	37	41.1628
20	40	−31.6586
21	42	−31.6891
22	44	57.4995
23	46	73.4509
24	48	−396.1540
25	50	81.0098

TABLE 28 — Zoom lens group data

				Position	Position
				of front	of rear
	First	Focal	Total	principal	principal
Group	surface	length	length	point	point
1	1	17.67884	317.47250	61.08007	212.01761
2	31	83.48585	14.02040	6.33935	10.23768
3	37	−82.35184	28.70780	25.69887	26.84023
4	46	46.71049	35.95580	12.56350	19.78117
Zoom lens group magnification
	First	WIDE-	INTER-
Group	surface	ANGLE	MEDIATE	TELEPHOTO
1	1	−0.01594	−0.01594	−0.01594
2	31	−1.17070	−1.21551	−1.27041
3	37	−1.22561	−1.20566	−1.17781
4	46	−0.28551	−0.28865	−0.29319

TABLE 29

Cond.	Ex. 1	Ex. 2	Ex. 3	Ex. 4	Ex. 5	Ex. 6	Ex. 7
(1)	8.7	7.3	9.7	7.5	9.2	9.5	11.1
(2)	5.5	5.2	5.2	6.8	4.0	5.1	4.7
(3)	1.10	0.89	1.06	1.14	1.09	1.15	1.19
(4)	0.48	0.50	0.37	0.47	0.56	0.60	0.62
(5)	8.2	7.2	8.8	8.5	7.3	3.5	8.1
(6)	3.5	3.4	3.3	3.9	3.0	3.5	3.4
(7)	8.9	5.4	4.7	9.8	6.9	9.1	8.4
(8)	20.4	19.1	25.5	23.0	14.7	15.1	14.8
(9)	12.2	14.6	11.1	12.0	12.2	11.7	11.5
(10)	11.7	14.3	10.2	11.6	11.9	11.4	11.4
(11)	6.5	6.8	6.3	6.5	6.6	6.5	6.5
(12)	3.1	3.9	3.6	2.9	3.0	2.9	1.4
(13)	4.0	3.3	4.3	4.1	2.8	3.6	3.3
(14)	>0	>0	>0	>0	>0	>0	>0
(15)	See (15), (16) in Tables 31 and 32
(16)
(17)	66.4	66.3	66.3	66.3	66.4	66.4	66.4

TABLE 30 — ym is a height at the telephoto end at which the most off-axis main ray passes through the lens surface.

Var.	Ex. 1	Ex. 2	Ex. 3	Ex. 4	Ex. 5	Ex. 6	Ex. 7
Ts	63.23	53.34	70.04	54.35	66.79	69.03	80.24
fw	−7.24	−7.28	−7.25	−7.25	−7.25	−7.23	−7.23
Tpr	39.77	37.71	37.82	49.56	29.21	36.65	34.23
Tp	242.00	217.69	237.45	245.92	240.58	247.31	256.37
Tr	219.93	244.24	224.48	216.01	221.35	214.62	215.55
fp	13.59	13.18	13.10	13.34	14.27	15.00	15.56
fr	28.25	26.61	35.16	28.63	25.58	25.06	24.92
fpr	59.29	52.72	63.56	61.34	53.00	25.06	58.80
fpf	25.67	24.49	24.19	28.34	21.51	25.43	24.51
T12	64.39	38.98	34.40	70.78	49.77	65.75	60.97
fr1	−147.67	−138.81	−185.08	−166.85	−106.28	−108.91	−106.75
fr2	88.43	106.43	80.54	86.73	88.54	84.37	83.49
fr3	−84.48	−103.99	−74.05	−84.27	−86.18	−82.73	−82.35
fr4	47.05	49.84	45.95	46.86	48.20	47.12	46.71
T1	22.18	28.66	25.74	20.90	21.95	21.16	9.89
Tm	29.27	24.37	31.37	29.76	20.43	25.97	23.74
ωm	66.38	66.31	66.30	66.34	66.39	66.45	66.39
ym	See ym in Table 31
Ts is the longest air distance,
Tp is a distance from a surface closest to the magnification side of the magnification optical system to the intermediate imaging position,
Tr is a distance from the intermediate imaging position at the wide-angle end to a surface closest to the reduction side of the relay optical system,
Tpr is a distance from a surface closest to the magnification side of the magnification optical system rear group to the intermediate imaging position,
T12 is an air distance between the first lens group and the second lens group at the wide-angle end,
T1 is an air distance between the first lens element and the second lens element,
Tm is a distance from a surface on the reduction side of the magnification optical system to a surface on the magnification side of the relay optical system,
fw is a focal length of the entire system at a wide-angle end thereof,
fp is a focal length of the magnification optical system,
fr is a focal length of the relay optical system at the wide-angle end,
fpr is a focal length of the magnification optical system rear group,
fpf is a focal length of the magnification optical system front group,
fr1 is a focal length of the first lens group,
fr2 is a focal length of the second lens group,
fr3 is a focal length of the third lens group,
fr4 is a focal length of the fourth lens group,
ωm is a maximum half angle of view at the wide-angle end, and

TABLE 31A

	Example 1	Example 2
	Lens				Lens
	material	ym	(15)	(16)	material	ym	(15)	(16)
L1	Z330R	54.61	3.30	123	Z330R	55.90	3.37	123
L2	TAF3D	28.81	1.74	692	NBFD10	22.63	1.36	585
L3	NBF1	19.38	1.17	588	TAF3D	17.09	1.03	692
L4	FF5	−0.78	0.05	515	FCD1	0.08	0.00	457
L5	K-CSK120	−3.01	0.18	498	K-CSK120	−1.81	0.11	498
L6	FCD1	−5.24	0.32	457	FCD1	−3.25	0.20	457
L7	FDS20-W	−9.00	0.54	589	FDS20-W	−6.48	0.39	589
L8	FCD1	−11.21	0.68	457	FCD1	−8.35	0.50	457
L9	S-FSL 5	−17.15	1.04	500	S-FSL 5	−14.06	0.85	500
L10	FCD1	−20.42	1.23	457	FCD1	−19.94	1.20	457
L11	E-FDS1-W	−39.76	2.40	666	TAF3D	−37.11	2.24	692
L12	E-FDS1-W	−34.69	2.10	666	E-FDS1-W	−31.96	1.93	666
L13	TAF1	−21.10	1.28	655	TAF1	−19.92	1.20	655
L14	LAC14	−20.27	1.23	637	BACD16	−19.70	1.19	644
L15	FDS20-W	−21.57	1.30	589	TAF3D	−25.29	1.52	692
L16	LAC14	−7.59	0.46	637	TAC8	−19.16	1.15	679
L17	S-NBH53V	−7.29	0.44	538	K-CSK120	−6.06	0.37	498
L18	FCD515	−4.21	0.25	540	FCD100	−4.44	0.27	404
L19	FF5	−0.07	0.00	515	FF5	−0.07	0.00	515
L20	S-NBH52V	0.25	0.02	497	BACED5	0.07	0.00	601
L21	S-NBH52V	4.73	0.29	497	S-NBH52V	6.86	0.41	497
L22	FCD100	5.74	0.35	404	FCD100	7.89	0.48	404
L23	FCD1	13.34	0.81	457	FCD1	13.58	0.82	457
L24	BACD15	15.91	0.96	656	S-TIL25	15.30	0.92	588
L25	FCD100	17.22	1.04	404	FCD100	16.74	1.01	404

TABLE 31B — Example 3 Lens

	material	ym	(15)	(16)
L1	Z330R	59.40	3.60	123
L2	TAC8	29.57	1.79	679
L3	TAC8	19.80	1.20	679
L4	S-FSL 5	4.32	0.26	500
L5	FCD1	−2.48	0.15	457
L6	S-NBH53V	−3.08	0.19	538
L7	FCD1	−4.79	0.29	457
L8	FDS20-W	−7.73	0.47	589
L9	FCD1	−9.96	0.60	457
L10	TAC8	−14.50	0.88	679
L11	FCD1	−17.91	1.08	457
L12	E-FDS1-W	−38.97	2.36	666
L13	E-FDS1-W	−36.24	2.20	666
L14	PCD51	−23.63	1.43	499
L15	S-FSL 5	−21.41	1.30	500
L16	FDS20-W	−21.50	1.30	589
L17	S-NBH53V	−12.35	0.75	538
L18	TAC8	−11.65	0.71	679
L19	FCD515	−0.58	0.04	540
L20	FF5	0.00	0.00	515
L21	BACED5	1.55	0.09	601
L22	S-NBH53V	6.06	0.37	538
L23	FCD100	7.21	0.44	404
L24	FCD1	15.48	0.94	457
L25	S-NBH52V	17.66	1.07	497
L26	FCD100	18.56	1.12	404

TABLE 32A

	Example 4	Example 5
	Lens			Lens
	material	(15)	(16)	material	(15)	(16)
L1	Z330R	3.3	123	Z330R	3.3	123
L2	TAF3D	1.8	692	TAF3D	1.7	692
L3	NBF1	1.2	588	NBF1	1.2	588
L4	FF5	0.0	515	FF5	0.3	515
L5	K-CSK120	0.2	498	K-CSK120	0.2	498
L6	FCD1	0.3	457	FCD1	0.3	457
L7	FDS20-W	0.6	589	FDS20-W	0.5	589
L8	FCD1	0.7	457	FCD1	0.6	457
L9	S-FSL 5	1.1	500	S-FSL 5	1.0	500
L10	FCD1	1.3	457	FCD1	1.2	457
L11	E-FDS1-W	2.4	666	E-FDS1-W	2.3	666
L12	E-FDS1-W	2.1	666	E-FDS1-W	1.9	666
L13	TAF1	1.3	655	TAF1	1.2	655
L14	LAC14	1.2	637	LAC14	1.2	637
L15	FDS20-W	1.3	589	FDS20-W	1.2	589
L16	LAC14	0.4	637	LAC14	0.5	637
L17	S-NBH53V	0.3	538	S-NBH53V	0.5	538
L18	FCD515	0.3	540	FCD515	0.3	540
L19	FF5	0.0	515	FF5	0.0	515
L20	S-NBH52V	0.0	497	S-NBH52V	0.0	497
L21	S-NBH52V	0.3	497	S-NBH52V	0.3	497
L22	FCD100	0.3	404	FCD100	0.3	404
L23	FCD1	0.8	457	FCD1	0.8	457
L24	BACD15	0.9	656	BACD15	0.9	656
L25	FCD100	1.0	404	FCD100	1.0	404

TABLE 32B

	Example 6	Example 7
	Lens			Lens
	material	(15)	(16)	material	(15)	(16)
L1	Z330R	3.2	123	Z330R	3.5	123
L2	TAF3D	1.7	692	TAF3D	2.4	692
L3	NBF1	1.2	588	NBF1	1.4	588
L4	FF5	0.1	515	FF5	0.5	515
L5	K-CSK120	0.2	498	K-CSK120	0.2	498
L6	FCD1	0.4	457	FCD1	0.4	457
L7	FDS20-W	0.7	589	FDS20-W	0.6	589
L8	FCD1	0.8	457	FCD1	0.7	457
L9	S-FSL 5	1.2	500	S-FSL 5	1.1	500
L10	FCD1	1.4	457	FCD1	1.3	457
L11	E-FDS1-W	2.5	666	E-FDS1-W	2.6	666
L12	E-FDS1-W	2.2	666	E-FDS1-W	2.2	666
L13	TAF1	1.3	655	TAF1	1.3	655
L14	LAC14	1.2	637	LAC14	1.2	637
L15	FDS20-W	1.2	589	FDS20-W	1.3	589
L16	LAC14	0.3	637	LAC14	0.4	637
L17	S-NBH53V	0.3	538	S-NBH53V	0.4	538
L18	FCD515	0.3	540	FCD515	0.3	540
L19	FF5	0.0	515	FF5	0.0	515
L20	S-NBH52V	0.0	497	S-NBH52V	0.0	497
L21	S-NBH52V	0.3	497	S-NBH52V	0.2	497
L22	FCD100	0.3	404	FCD100	0.3	404
L23	FCD1	0.8	457	FCD1	0.8	457
L24	BACD15	0.9	656	BACD15	0.9	656
L25	FCD100	1.0	404	FCD100	1.0	404

Claims as granted

20 claims

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4 codes

IPC · International Patent Classification

Section G — Physics

G03B5/02
G02B13/16
G02B13/02
G02B15/14

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