Camera optical lens

This application claims the priority benefit of Chinese Patent Applications Ser. No. 201710975239.4 and Ser. No. 201710975242.6 filed on Oct. 19, 2017, the entire content of which is incorporated herein by reference.

The present disclosure relates to optical lens, in particular to a camera optical lens suitable for handheld devices such as smart phones and digital cameras and imaging devices.

With the emergence of smart phones in recent years, the demand for miniature camera lens is increasing day by day, but the photosensitive devices of general camera lens are no other than Charge Coupled Device (CCD) or Complementary metal-Oxide Semiconductor Sensor (CMOS sensor), and as the progress of the semiconductor manufacturing technology makes the pixel size of the photosensitive devices shrink, coupled with the current development trend of electronic products being that their functions should be better and their shape should be thin and small, miniature camera lens with good imaging quality therefor has become a mainstream in the market. In order to obtain better imaging quality, the lens that is traditionally equipped in mobile phone cameras adopts a three-piece or four-piece lens structure. And, with the development of technology and the increase of the diverse demands of users, and under this circumstances that the pixel area of photosensitive devices is shrinking steadily and the requirement of the system for the imaging quality is improving constantly, the five-piece, six-piece and seven-piece lens structure gradually appear in lens design. There is an urgent need for ultra-thin wide-angle camera lenses which have good optical characteristics and the chromatic aberration of which is fully corrected.

Many aspects of the exemplary embodiments can be better understood with reference to the following drawings. The components in the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure.

FIG. 1 is a schematic diagram of a camera optical lens in accordance with a first embodiment of the present invention;

FIG. 2 shows the axial aberration of the camera optical lens shown in FIG. 1 ;

FIG. 3 shows the ratio chromatic aberration of the camera optical lens shown in FIG. 1 ;

FIG. 4 presents a schematic diagram of the field curvature and distortion of the camera optical lens shown in FIG. 1 ;

FIG. 5 is a schematic diagram of a camera optical lens in accordance with a second embodiment of the present invention;

FIG. 6 presents the axial aberration of the camera optical lens shown in FIG. 5 ;

FIG. 7 presents the ratio chromatic aberration of the camera optical lens shown in FIG. 5 ;

FIG. 8 presents the field curvature and distortion of the camera optical lens shown in FIG. 5

The present disclosure will hereinafter be described in detail with reference to several exemplary embodiments. To make the technical problems to be solved, technical solutions and beneficial effects of the present disclosure more apparent, the present disclosure is described in further detail together with the figure and the embodiments. It should be understood the specific embodiments described hereby is only to explain the disclosure, not intended to limit the disclosure.

Referring to FIG. 1 , the present disclosure provides a camera optical lens 10 in accordance with a first exemplary embodiment. The camera optical lens 10 comprises 7 lenses. Concretely, from an object side to an image side, the camera optical lens 10 comprises in sequence: an aperture S1, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7. Optical elements including optical filters GF can be arranged between the seventh lens L7 and the image surface S1. The first lens L1 is made of glass material, the second lens L2 is made of plastic material, the third lens L3 is made of plastic material, the fourth lens L4 is made of plastic material, the fifth lens L5 is made of plastic material, the sixth lens L6 is made of plastic material, the seventh lens L7 is made of plastic material.

Here, the focal length of the whole optical camera lens is defined as f, the focal length of the first lens L1 is defined as f1, the focal length of the third lens L3 is defined as f3, the focal length of the fourth lens L4 is defined as f4, the refractive power of the first lens L1 is defined as n1, the thickness on-axis of the first lens L1 is defined as d1, the total optical length of the camera optical lens is defined as TTL, the curvature radius of the seventh lens L7 at the object side surface is defined as R13, the curvature radius of the seventh lens L7 at the image side surface is defined as R14. The f, f1, f3, f4, n4, d7, TTL, R13 and R14 satisfy the following conditions: 1 f1/f 1.5, 1.7 n1 2.2, −2 f3/f4 2; −10 (R13+R14)/(R13−R14) 10; 0.01 d1/TTL 0.05.

Condition 1 f1/f 1.5 fixes the positive refractive power of the first lens L1. If the lower limit of the set value is exceeded, although it benefits the development of ultra-thin lenses, but the positive refractive power of the first lens L1 will be too strong, problems like aberration are difficult to be corrected, and it is also unfavorable for the development of wide-angle lens. On the contrary, if the higher limit of the set value is exceeded, the positive refractive power of the first lens L1 will become too weak, it is then difficult to develop ultra-thin lenses. Preferably, the following condition shall be satisfied, 1 f1/f 1.1.

Condition 1.7 n1 2.2 fixes the refractive power of the first lens L1, a refractive power within this range benefits the development of ultra-thin lenses, and it also benefits the correction of aberration. Preferably, the following condition shall be satisfied, 1.7 n1 1.8.

Condition −2 f3/f4 2 fixes the ratio between the focal length f3 of the third lens L3 and the focal length f4 of the fourth lens L4, a ratio within this range can effectively reduce the sensitivity of the camera optical lenses group and further enhance the imaging quality. Preferably, the following condition shall be satisfied, −1.8 f3/f4 −0.75.

Condition −10 (R13+R14)/(R13−R14) 10 fixes the shape of the seventh lens L7, a value beyond this range, with the development into the direction of ultra-thin and wide-angle lenses, problems like aberration of the off-axis picture angle are difficult to be corrected. Preferably, the following condition shall be satisfied, 0 (R13+R14)/(R13−R14) 2.

Condition 0.01 d1/TTL 0.055 fixes the ratio between the thickness on-axis of the first lens L1 and the total optical length TTL of the camera optical lens 10 , a ratio within this range benefits the development of ultra-thin lenses.

When the focal length of the camera optical lens 10 of the present invention, the focal lengths of all lenses, the refractive power of the related lenses, the total optical length, the thickness on-axis and the curvature radius of the camera optical lens satisfy the above conditions, the camera optical lens 10 has the advantage of high performance and satisfies the design requirement of low TTL.

In this embodiment, the object side surface of the first lens L1 is a convex surface relative to the proximal axis, its image side surface is a concave surface relative to the proximal axis, and it has a positive refractive power; the focal length of the whole optical camera lens is f, the focal length of the first lens L1 f1, the curvature radius of the first lens L1 at the object side surface R1, the curvature radius of the first lens L1 at the image side surface R2 and the thickness on-axis of the first lens L1 d1 satisfy the following condition: −3.83 (R1+R2)/(R1−R2) −1.27, this condition reasonably controls the shape of the first lens, then the first lens system can effectively correct the spherical aberration of the system; 0.13 d1 0.38, satisfying this condition is conducive to the realization of ultra-thin lens. Preferably, the following conditions shall be satisfied, −2.39 (R1+R2)/(R1−R2) −1.59; 0.2 d1 0.3.

In this embodiment, the object side surface of the second lens L2 is a convex surface relative to the proximal axis, its image side surface is a concave surface relative to the proximal axis, and it has a negative refractive power; the focal length of the whole optical camera lens 10 is f, the focal length of the second lens L2 f2, the curvature radius of the second lens L2 at the object side surface R3, the curvature radius of the second lens L2 at the image side surface R4 and the thickness on-axis of the second lens L2 d3 satisfy the following condition: −5.26 f2/f −1.57, this condition controls the negative refractive power of the second lens L2 within the reasonable scope, the spherical aberration caused by the first lens L1 which has positive refractive power and the field curvature of the system then can be reasonably and effectively balanced; the condition 1.2 (R3+R4)/(R3−R4) 3.83 fixes the shape of the second lens L2, a value beyond this range, with the development into the direction of ultra-thin and wide-angle lenses, the problem of on-axis chromatic aberration is difficult to be corrected; 0.12 d3 0.39, satisfying this condition is conducive to the realization of ultra-thin lenses. Preferably, the following conditions shall be satisfied, −3.29 f2/f −1.97; 1.91 (R3+R4)/(R3−R4) 3.06; 0.19 d3 0.31.

In this embodiment, the object side surface of the third lens L3 is a convex surface relative to the proximal axis, its image side surface is a concave surface relative to the proximal axis, and it has a negative refractive power; the focal length of the whole optical camera lens 10 is f, the focal length of the third lens L3 f3, the curvature radius of the third lens L3 at the object side surface R5, the curvature radius of the third lens L3 at the image side surface R6 and the thickness on-axis of the third lens L3 d5 satisfy the conditions: −5.03 f3/f −1.49, −5.03 f3/f −1.49, satisfying this condition is helpful for the system to obtain good ability in balancing the field curvature, so that the image quality can be effectively improved; the condition −2.59 (R5+R6)/(R5−R6) −0.84 can effectively control the shape of the third lens L3, which is beneficial to the shaping of the third lens L3 and avoids bad shaping and stress generation due to the large surface curvature of the third lens 13 ; 0.10 d5 0.32, satisfying this condition is conducive to the realization of ultra-thin lenses. Preferably, the following conditions shall be satisfied, −3.14 f3/f −1.87; −1.62 (R5+R6)/(R5−R6) −1.05; 0.16 d5 0.25.

In this embodiment, the object side surface of the fourth lens L4 is a convex surface relative to the proximal axis, its image side surface is a concave surface relative to the proximal axis, and it has a positive refractive power; the focal length of the whole optical camera lens 10 is f, the focal length of the fourth lens L4 f4, the curvature radius of the fourth lens L4 at the object side surface R7, the curvature radius of the fourth lens L4 at the image side surface R8 and the thickness on-axis of the fourth lens L4 d7 satisfy the condition: 0.78 f4/f 3.45, which, through the reasonable distribution of light intensity, makes it possible that the system has better imaging quality and lower sensitivity; the condition −1.48 (R7+R8)/(R7−R8) −0.13 fixes the shape of the fourth lens L4, a value beyond this range, with the development into the direction of ultra-thin and wide-angle lenses, the problem of off-axis chromatic aberration is difficult to be corrected; 0.28 d7 0.83, satisfying this condition is conducive to the realization of ultra-thin lenses. Preferably, the following conditions shall be satisfied, 1.25 f4/f 2.76; −0.92 (R7+R8)/(R7−R8) −0.16; 0.44 d7 0.66.

In this embodiment, the object side surface of the fifth lens L5 is a convex surface relative to the proximal axis, its image side surface is a concave surface relative to the proximal axis, and it has a positive refractive power; the focal length of the whole optical camera lens 10 is f, the focal length of the fifth lens L5 f5, the curvature radius of the fifth lens L5 at the object side surface R9, the curvature radius of the fifth lens L5 at the image side surface R10 and the thickness on-axis of the fifth lens L5 d9 satisfy the conditions: 1.67 f5/f 9.4, the limitation puts on the fifth lens L5 can effectively make the light angle of the camera lens flat and reduce the tolerance sensitivity; the condition −4.48 (R9+R10)/(R9−R10) −1.1 fixes the shape of the fifth lens L5, a value beyond this range, with the development into the direction of ultra-thin and wide-angle lenses, the problem of off-axis chromatic aberration is difficult to be corrected; 0.24 d9 0.72, satisfying this condition is conducive to the realization of ultra-thin lenses. Preferably, the following conditions shall be satisfied, 2.68 f5/f 7.52; −2.8 (R9+R10)/(R9−R10) −1.37; 0.38 d9 0.58.

In this embodiment, the object side surface of the sixth lens L6 is a convex surface relative to the proximal axis, its image side surface is a concave surface relative to the proximal axis, and it has a positive refractive power; the focal length of the whole optical camera lens 10 is f, the focal length of the sixth lens L6 f6, the curvature radius of the sixth lens L6 at the object side surface R11, the curvature radius of the sixth lens L6 at the image side surface R12 and the thickness on the axis of the sixth lens L6 d11 satisfy the condition: 0.75 f6/f 2.39, which, through the reasonable distribution of light intensity, makes it possible that the system has better imaging quality and lower sensitivity; the condition −5.16 (R11+R12)/(R11−R12) −1.7 fixes the shape of the sixth lens L6, a value beyond this range, with the development into the direction of ultra-thin and wide-angle lenses, the problem of off-axis chromatic aberration is difficult to be corrected; 0.19 d11 0.59, satisfying this condition is conducive to the realization of ultra-thin lenses. Preferably, the following conditions shall be satisfied, 1.2 f6/f 1.91; −3.22 (R11+R12)/(R11−R12) −2.13; 0.3 d1 10.48.

In this embodiment, the object side surface of the seventh lens L7 is a convex surface relative to the proximal axis, its image side surface is a concave surface relative to the proximal axis, and it has a negative refractive power; the focal length of the whole optical camera lens 10 is f, the focal length of the seventh lens L7 f7 and the thickness on-axis of the seventh lens L7 d13 satisfy the conditions: −1.68 f7/f −0.5, which, through the reasonable distribution of light intensity, makes it possible that the system has better imaging quality and lower sensitivity; 0.14 d13 0.42, satisfying this condition is conducive to the realization of ultra-thin lenses. Preferably, the following conditions shall be satisfied, −1.05 f7/f −0.62; 0.22 d13 0.34.

In this embodiment, the total optical length TTL of the camera optical lens 10 is less than or equal to 5.4 millimeter, which is conducive to the realization of ultra-thin lenses. Preferably, the total optical length TTL of the camera optical lens 10 is less than or equal to 5.16.

In this embodiment, the aperture F number of the camera optical lens 10 is less than or equal to 2.06. A large aperture has better imaging performance. Preferably, the aperture F number of the camera optical lens 10 is less than or equal to 2.02.

Such a design is able to make the total optical length TTL of the whole camera optical lens 10 as short as possible, thus the miniaturization characteristics can be maintained.

In the following, an example will be used to describe the camera optical lens 10 of the present invention. The symbols recorded in each example are as follows. The unit of distance, radius and center thickness is mm.

TTL: Optical length (the distance on-axis from the object side surface to the image side surface of the first lens L1).

Preferably, inflexion points and/or arrest points can also be arranged on the object side surface and/or image side surface of the lens, so that the demand for high quality imaging can be satisfied, for the concrete embodiment, refer to the description below.

The design information of the camera optical lens 10 according to the first embodiment of the present invention is shown in the following, the unit of the focal length, distance, radius and center thickness is mm.

The design information of the camera optical lens 10 in the first embodiment of the present invention is shown in the tables 1 and 2.

Where, the meaning of the various symbols is as follows.

S1: Aperture;

R: The curvature radius of the optical surface, the central curvature radius in case of lens;

R1: The curvature radius of the first lens L1 on the object side;

R2: The curvature radius of the first lens L1 on the image side;

R3: The curvature radius of the second lens L2 on the object side;

R4: The curvature radius of the second lens L2 on the image side;

R5: The curvature radius of the third lens L3 on the object side;

R6: The curvature radius of the third lens L3 on the image side;

R7: The curvature radius of the fourth lens L4 on the object side;

R8: The curvature radius of the fourth lens L4 on the image side;

R9: The curvature radius of the fifth lens L5 on the object side;

R10: The curvature radius of the fifth lens L5 on the image side;

R11: The curvature radius of the sixth lens L6 on the object side;

R12: The curvature radius of the sixth lens L6 on the image side;

R13: The curvature radius of the seventh lens L7 on the object side;

R14: The curvature radius of the seventh lens L7 on the image side;

R15: The curvature radius of the optical filter GF on the object side;

R16: The curvature radius of the optical filter GF on the image side;

d: The distance on-axis between the thickness on-axis of the lens and the lens;

d0: The distance on-axis from aperture S1 to the object side surface of the first lens L1;

d1: The thickness on-axis of the first lens L1;

d2: The distance on-axis from the image side surface of the first lens L1 to the object side surface of the second lens L2;

d3: The thickness on-axis of the second lens L2;

d4: The distance on-axis from the image side surface of the second lens L2 to the object side surface of the third lens L3;

d5: The thickness on-axis of the third lens L3;

d6: The distance on-axis from the image side surface of the third lens L3 to the object side surface of the fourth lens L4;

d7: The thickness on-axis of the fourth lens L4;

d8: The distance on-axis from the image side surface of the fourth lens L4 to the object side surface of the fifth lens L5;

d9: The thickness on-axis of the fifth lens L5;

d10: The distance on-axis from the image side surface of the fifth lens L5 to the object side surface of the sixth lens L6;

d11: The thickness on-axis of the sixth lens L6;

d12: The distance on-axis from the image side surface of the sixth lens L6 to the object side surface of the seventh lens L7;

d13: The thickness on-axis of the seventh lens L7;

d14: The distance on-axis from the image side surface of the seventh lens L7 to the object side surface of the optical filter GF;

d15: The thickness on-axis of the optical filter GF;

d16: The distance on-axis from the image side surface to the image surface of the optical filter GF;

nd: The refractive power of the d line;

nd1: The refractive power of the d line of the first lens L1;

nd2: The refractive power of the d line of the second lens L2;

nd3: The refractive power of the d line of the third lens L3;

nd4: The refractive power of the d line of the fourth lens L4;

nd5: The refractive power of the d line of the fifth lens L5;

nd6: The refractive power of the d line of the sixth lens L6;

nd7: The refractive power of the d line of the seventh lens L7;

ndg: The refractive power of the d line of the optical filter GF;

vd: The abbe number;

v1: The abbe number of the first lens L1;

v2: The abbe number of the second lens L2;

v3: The abbe number of the third lens L3;

v4: The abbe number of the fourth lens L4;

v5: The abbe number of the fifth lens L5;

v6: The abbe number of the sixth lens L6;

v7: The abbe number of the seventh lens L7;

vg: The abbe number of the optical filter GF;

Table 2 shows the aspherical surface data of the camera optical lens 10 in the embodiment 1 of the present invention.

Where, K is conic index, A4, A6, A8, A10, A12, A14, A16 are aspheric surface indexes.

IH: Image height

y =( x 2 /R )/[1+{1−( k+ 1)( x 2 /R 2 )} 1/2 ]+ A 4 x 4 +A 6 x 6 +A 8 x 8 +A 10 x 10 +A 12 x 12 +A 14 x 14 +A 16 x 16   (1)

For convenience, the aspheric surface of each lens surface uses the aspheric surfaces shown in the above condition (1). However, the present invention is not limited to the aspherical polynomials form shown in the condition (1).

Table 3 and table 4 show the inflexion points and the arrest point design data of the camera optical lens 10 lens in embodiment 1 of the present invention. In which, R1 and R2 represent respectively the object side surface and image side surface of the first lens L1, R3 and R4 represent respectively the object side surface and image side surface of the second lens L2, R5 and R6 represent respectively the object side surface and image side surface of the third lens L3, R7 and R8 represent respectively the object side surface and image side surface of the fourth lens L4, R9 and R10 represent respectively the object side surface and image side surface of the fifth lens L5, R11 and R12 represent respectively the object side surface and image side surface of the sixth lens L6, R13 and R14 represent respectively the object side surface and image side surface of the seventh lens L7. The data in the “inflexion point position” columns are the vertical distances from the inflexion points arranged for each lens surface to the optic axis of the camera optical lens 10 . The data in the “arrest point position” column are the vertical distances from the arrest points arranged for each lens surface to the optic axis of the camera optical lens 10 .

FIG. 2 and FIG. 3 show the axial aberration and ratio chromatic aberration schematic diagrams after light with a wavelength of 470 nm, 555 nm and 650 nm passes the camera optical lens 10 in the first embodiment. FIG. 4 shows the field curvature and distortion schematic diagrams after light with a wavelength of 470 nm passes the camera optical lens 10 in the first embodiment, the field curvature S in FIG. 4 is a field curvature in the sagittal direction, T is a field curvature in the meridian direction.

Table 9 shows the various values of the Embodiments 1, 2 and the values corresponding with the parameters which are already specified in the condition expressions.

As shown in Table 9, the first embodiment satisfies the various conditions.

In this embodiment, the pupil entering diameter of the camera optical lens is 2 mm, the full vision field image height is 2.934 mm, the vision field angle in the diagonal direction is 72.04 degrees, it has wide-angle and is ultra-thin, its on-axis and off-axis chromatic aberrations are fully corrected, and it has excellent optical characteristics.

Embodiment 2 is basically the same as embodiment 1, the meaning of its symbols is the same as that of embodiment 1, in the following, only the differences are described.

Table 5 and table 6 show the design data of the camera optical lens 20 in embodiment 2 of the present invention.

Table 6 shows the aspherical surface data of each lens of the camera optical lens 20 in embodiment 2 of the present invention.

Tables 7 and 8 show the inflexion point and arrest point design data of each lens of the camera optical lens 20 in embodiment 2 of the present invention.

FIG. 6 and FIG. 7 show the axial aberration and ratio chromatic aberration schematic diagrams after light with a wavelength of 470 nm, 555 nm and 650 nm passes the camera optical lens 20 in the second embodiment. FIG. 8 shows the field curvature and distortion schematic diagrams after light with a wavelength of 470 nm passes the camera optical lens 20 in embodiment.

As shown in Table 9, the second embodiment 2 satisfies the various conditions.

In this embodiment, the pupil entering diameter of the camera optical lens is 2 mm, the full vision field image height is 2.934 mm, the vision field angle in the diagonal direction is 71.47°, it has wide-angle and is ultra-thin, its on-axis and off-axis chromatic aberrations are fully corrected, and it has excellent optical characteristics.

It is to be understood, however, that even though numerous characteristics and advantages of the present exemplary embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms where the appended claims are expressed.