Lens assembly

The invention relates to a lens assembly.

The current development trend of a lens assembly is toward miniaturization. Additionally, the lens assembly is developed to have high resolution and resistance to environmental temperature change in accordance with different application requirements. However, the known lens assembly can't satisfy such requirements. Therefore, the lens assembly needs a new structure in order to meet the requirements of miniaturization, high resolution, and resistance to environmental temperature change at the same time.

The invention provides a lens assembly to solve the above problems. The lens assembly of the invention is provided with characteristics of a shortened total lens length, an increased resolution, a resisted environmental temperature change, and still has a good optical performance.

The lens assembly in accordance with an exemplary embodiment of the invention includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens is with negative refractive power. The second lens is with refractive power. The third lens is with refractive power. The fourth lens is with positive refractive power and includes a convex surface facing an image side. The fifth lens is with refractive power. The sixth lens is with refractive power and includes a concave surface facing an object side. The seventh lens is with positive refractive power. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are arranged in order from the object side to the image side along an optical the axis. An air gap is disposed between the sixth lens and the seventh lens. The lens assembly satisfies at least one of the following conditions: −4<f 2 /f 6 <7; 0.7<f 3 /f 7 <1.1; 3<f 123 /f 4567 <2; wherein f 2 is an effective focal length of the second lens, f 3 is an effective focal length of the third lens, f 6 is an effective focal length of the sixth lens, f 7 is an effective focal length of the seventh lens, f 123 is an effective focal length of a combination of the first lens, the second lens, and the third lens, and f 4567 is an effective focal length of a combination of the fourth lens, the fifth lens, the sixth lens, and the seventh lens.

In another exemplary embodiment, the second lens is with negative refractive power and the third lens is with positive refractive power.

In yet another exemplary embodiment, the third lens includes a convex surface facing the object side, the fourth lens further includes a concave surface facing the object side, the sixth lens further includes a convex surface facing the image side, and the seventh lens includes a concave surface facing the image side.

In another exemplary embodiment, the fifth lens is a biconcave lens with negative refractive power and includes a concave surface facing the object side and another concave surface facing the image side.

In yet another exemplary embodiment, the lens assembly satisfies at least one of the following conditions: 0.7<f/IH<1.5; −15<(R 21 −R 22 )/(R 21 +R 22 )<0.8; −6<R 61 /R 31 <30; −2<R 42 /R 51 <−0.8; 0.2<Vd 5 /Vd 6 <3; 3<TTL/BFL<5; 0.5<Gap23/Gap67<0.75; wherein f is an effective focal length of the lens assembly, IH is a half image height of the lens assembly, R 21 is a radius of curvature of an object side surface of the second lens, R 22 is a radius of curvature of an image side surface of the second lens, R 31 is a radius of curvature of an object side surface of the third lens, R 42 is a radius of curvature of an image side surface of the fourth lens, R 51 is a radius of curvature of an object side surface of the fifth lens, R 61 is a radius of curvature of an image side surface of the sixth lens, Vd 5 is an Abbe number of the fifth lens, Vd 6 is an Abbe number of the sixth lens, TTL is an interval from an object side surface of the first lens to an image plane along the optical axis, BFL is an interval from an image side surface of the seventh lens to the image plane along the optical axis, Gap23 is an interval from an image side surface of the second lens to an object side surface of the third lens along the optical axis, and Gap67 is an interval from an image side surface of the sixth lens to an object side surface of the seventh lens along the optical axis.

In another exemplary embodiment, the fifth lens is with positive refractive power and the sixth lens is with negative refractive power.

In yet another exemplary embodiment, the third lens includes a convex surface facing the object side.

In another exemplary embodiment, the fifth lens is with negative refractive power and the sixth lens is with positive refractive power.

In yet another exemplary embodiment, the third lens includes a convex surface facing the object side, the fifth lens is a biconcave lens and includes a concave surface facing the object side and another concave surface facing the image side, and the sixth lens further includes a convex surface facing the image side.

In another exemplary embodiment, the fifth lens is with positive refractive power and the sixth lens is with positive refractive power.

In yet another exemplary embodiment, the second lens is with positive refractive power and the third lens is with negative refractive power.

A detailed description is given in the following embodiments with reference to the accompanying drawings.

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 is a lens layout diagram of a lens assembly in accordance with a first embodiment of the invention;

FIG. 2 A , FIG. 2 B , and FIG. 2 C depict a longitudinal spherical aberration diagram, an astigmatic field curves diagram, and a distortion diagram of the lens assembly in accordance with the first embodiment of the invention, respectively;

FIG. 3 is a lens layout diagram of a lens assembly in accordance with a second embodiment of the invention;

FIG. 4 A , FIG. 4 B , and FIG. 4 C depict a longitudinal spherical aberration diagram, an astigmatic field curves diagram, and a distortion diagram of the lens assembly in accordance with the second embodiment of the invention, respectively;

FIG. 5 is a lens layout diagram of a lens assembly in accordance with a third embodiment of the invention;

FIG. 6 A , FIG. 6 B , and FIG. 6 C depict a longitudinal spherical aberration diagram, an astigmatic field curves diagram, and a distortion diagram of the lens assembly in accordance with the third embodiment of the invention, respectively;

FIG. 7 is a lens layout diagram of a lens assembly in accordance with a fourth embodiment of the invention;

FIG. 8 A , FIG. 8 B , and FIG. 8 C depict a longitudinal spherical aberration diagram, an astigmatic field curves diagram, and a distortion diagram of the lens assembly in accordance with the fourth embodiment of the invention, respectively;

FIG. 9 is a lens layout diagram of a lens assembly in accordance with a fifth embodiment of the invention;

FIG. 10 A , FIG. 10 B , and FIG. 10 C depict a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the lens assembly in accordance with the fifth embodiment of the invention, respectively;

FIG. 11 is a lens layout diagram of a lens assembly in accordance with a sixth embodiment of the invention;

FIG. 12 A , FIG. 12 B , and FIG. 12 C depict a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the lens assembly in accordance with the sixth embodiment of the invention, respectively;

FIG. 13 is a lens layout diagram of a lens assembly in accordance with a seventh embodiment of the invention; and

FIG. 14 A , FIG. 14 B , and FIG. 14 C depict a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the lens assembly in accordance with the seventh embodiment of the invention, respectively.

The following description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.

The present invention provides a lens assembly including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens is with refractive power. The second lens is with refractive power. The third lens is with refractive power. The fourth lens is with positive refractive power and includes a convex surface facing an image side. The fifth lens is with refractive power. The sixth lens is with refractive power and includes a concave surface facing an object side. The seventh lens is with positive refractive power. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are arranged in order from the object side to the image side along an optical axis. An air gap is disposed between the sixth lens and the seventh lens. The lens assembly satisfies: 0.7<f/IH<1.5; wherein f is an effective focal length of the lens assembly and IH is a half image height of the lens assembly.

Referring to Table 1, Table 3, Table 5, and Table 7, wherein Table 1, Table 3, Table 5, and Table 7 show optical specification in accordance with a first, second, third, and fourth embodiments of the invention, respectively.

FIG. 1 , FIG. 3 , FIG. 5 , and FIG. 7 are lens layout diagrams of the lens assemblies in accordance with the first, second, third, and fourth embodiments of the invention, respectively.

The first lenses L 11 , L 21 , L 31 , L 41 are meniscus lenses with negative refractive power and made of glass material, wherein the object side surfaces S 11 , S 21 , S 31 , S 41 are convex surfaces, the image side surfaces S 12 , S 22 , S 32 , S 42 are concave surfaces, and both of the object side surfaces S 11 , S 21 S 31 , S 41 and image side surfaces S 12 , S 22 , S 32 , S 42 are spherical surfaces.

The second lenses L 12 , L 22 , L 32 , L 42 are made of glass material, wherein both of the object side surfaces S 13 , S 23 , S 33 , S 43 and image side surfaces S 14 . S 24 , S 34 , S 44 are spherical surfaces.

The third lenses L 13 , L 23 , L 33 , L 43 are made of glass material, wherein the object side surfaces S 15 , S 25 , S 35 . S 45 are convex surfaces and both of the object side surfaces S 15 , S 25 , S 35 , S 45 and image side surfaces S 16 , S 26 , S 36 , S 46 are spherical surfaces.

The fourth lenses L 14 , L 24 , L 34 , L 44 are biconvex lenses with positive refractive power and made of glass material, wherein the object side surfaces S 18 , S 28 , S 38 , S 48 are convex surfaces, the image side surfaces S 19 , S 29 , S 39 , S 49 are convex surfaces, and both of the object side surfaces S 18 , S 28 , S 38 , S 48 and image side surfaces S 19 , S 29 , S 39 , S 49 are spherical surfaces.

The fifth lenses L 15 , L 25 , L 35 , L 45 are made of glass material, wherein both of the object side surfaces S 110 , S 210 , S 310 , S 410 and image side surfaces S 111 , S 211 , S 311 , S 411 are spherical surfaces.

The sixth lenses L 16 , L 26 , L 36 , L 46 are made of glass material, wherein the object side surfaces S 112 , S 212 , S 312 , S 412 are concave surfaces and both of the object side surfaces S 112 , S 212 , S 312 , S 412 and image side surfaces S 113 , S 213 , S 313 , S 413 are spherical surfaces.

The seventh lenses L 17 , L 27 , L 37 , L 47 are biconvex lenses with positive refractive power and made of glass material, wherein the object side surfaces S 114 , S 214 S 314 , S 414 are convex surfaces, the image side surfaces S 115 S 215 S 315 , S 415 are convex surfaces, and both of the object side surfaces S 114 , S 214 , S 314 , S 414 and image side surfaces S 115 , S 215 , S 315 , S 415 are spherical surfaces.

In addition, the lens assemblies 1 , 2 , 3 , 4 satisfy at least one of the following conditions:

0.7< f/IH< 1.5;  (1)

3< TTL/BFL< 5;  (2)

−15<( R 21 −R 22 )/( R 21 +R 22 )<0.8;  (3)

−6< R 61 /R 31 <30;  (4)

−4< f 2 /f 6 <7;  (5)

0.2< Vd 5 /Vd 6 <3;  (6)

−3< f 123 /f 4567 <2;  (7)

wherein f is an effective focal length of the lens assemblies 1 , 2 , 3 , 4 for the first to fourth embodiments, f 2 is an effective focal length of the second lenses L 12 , l 22 , L 32 , L 42 for the first to fourth embodiments, f 6 is an effective focal length of the sixth lenses L 16 , 126 , L 36 , L 46 for the first to fourth embodiments, f 123 is an effective focal length of a combination of the first lenses L 11 , L 21 , L 31 , L 41 , the second lenses L 12 , L 22 , L 32 , L 42 , and the third lenses L 13 L 23 , L 33 , L 43 for the first to fourth embodiments, f 4567 is an effective focal length of a combination of the fourth lenses L 14 , L 24 L 34 , L 44 , the fifth lenses L 15 , L 25 , L 35 , L 45 , the sixth lenses L 16 L 26 , L 36 , L 46 , and the seventh lenses L 17 , L 27 , L 37 , L 47 for the first to fourth embodiments, IH is a half image height of the lens assemblies 1 , 2 , 3 , 4 for the first to fourth embodiments, TTL is respectively an interval from the object side surfaces S 11 , S 21 , S 31 S 41 of the first lenses L 11 , L 21 , L 31 , L 41 to the image planes IMA 1 , IMA 2 , IMA 3 , IMA 4 along the optical axes OA 1 , OA 2 , OA 3 , OA 4 for the first to fourth embodiments, BFL is respectively an interval from the image side surfaces S 115 , S 215 , S 315 , S 415 of the seventh lenses L 17 , L 27 , L 37 , L 47 to the image planes IMA 1 , IMA 2 , IMA 3 , IMA 4 along the optical axes OA 1 , OA 2 , OA 3 , OA 4 for the first to fourth embodiments, R 21 is a radius of curvature of the object side surfaces S 13 , S 23 , S 33 , S 43 of the second lenses L 12 , L 22 , L 32 , L 42 for the first to fourth embodiments, R 22 is a radius of curvature of the image side surfaces S 14 , S 24 , S 34 , S 44 of the second lenses L 12 , L 22 , L 32 , L 42 for the first to fourth embodiments, R 31 is a radius of curvature of the object side surfaces S 15 , S 25 , S 35 , S 45 of the third lenses L 13 , L 23 , L 33 , L 43 for the first to fourth embodiments, R 61 is a radius of curvature of the object side surfaces S 112 , S 212 , S 312 , S 412 of the sixth lenses L 16 , L 26 , L 36 , L 46 for the first to fourth embodiments, Vd 5 is an Abbe number of the fifth lenses L 15 , L 25 , L 35 , L 45 for the first to fourth embodiments, and Vd 6 is an Abbe number of the sixth lenses L 16 , L 26 , L 36 , L 46 for the first to fourth embodiments. With the lens assemblies 1 , 2 , 3 , 4 satisfying at least one of the above conditions (1)-(7), the total lens length can be effectively shortened, the field of view can be effectively increased, the resolution can be effectively increased, the environmental temperature change can be effectively resisted, the aberration can be effectively corrected, and the chromatic aberration can be effectively corrected.

When the condition (1): 0.7<f/IH<1.5 is satisfied, the refractive power of the lens assembly is sufficient to control the field of view and of benefit to correct aberration.

When the condition (2): 3<TTL/BFL<5 is satisfied, the total lens length of the lens assembly can be shortened.

When the condition (3): −15<(R 21 −R 22 )/(R 21 +R 22 )<0.8 is satisfied, the refractive power of the lens assembly is sufficient to control the field of view and of benefit to correct aberration.

When the condition (4): −6<R 61 /R 31 <30 is satisfied, can have proper radius of curvature to correct distortion.

When the condition (5): −4<f 2 /f 6 <7 is satisfied, the aberration can be corrected and the resolution can be increased.

When the condition (6): 0.2<Vd 5 /Vd 6 <3 is satisfied, the aberration can be corrected and the resolution can be increased.

When the condition (7): −3<f 123 /f 4567 <2 is satisfied, the aberration can be corrected and the resolution can be increased.

The common effect of condition (1): 0.7<f/IH<1.5 and condition (2): 3<TTL/BFL<5 is to provide a larger field of view for the lens assembly.

A detailed description of a lens assembly in accordance with a first embodiment of the invention is as follows. Referring to FIG. 1 , the lens assembly 1 includes a first lens L 11 , a second lens L 12 , a third lens L 13 , a stop ST 1 , a fourth lens L 14 , a fifth lens L 15 , a sixth lens L 16 , a seventh lens L 17 , and an optical filter OF 1 , all of which are arranged in order from an object side to an image side along an optical axis OA 1 . In operation, the light from the object side is imaged on an image plane IMA 1 .

According to the foregoing, wherein: the second lens L 12 is a meniscus lens with negative refractive power, wherein the object side surface S 13 is a concave surface and the image side surface S 14 is a convex surface; the third lens L 13 is a biconvex lens with positive refractive power, wherein the object side surface S 15 is a convex surface; the fifth lens L 15 is a biconvex lens with positive refractive power, wherein the object side surface S 110 is a convex surface and the image side surface S 111 is a convex surface; the sixth lens L 16 is a biconcave lens with negative refractive power, wherein the image side surface S 113 is a concave surface; and both of the object side surface S 116 and image side surface S 117 of the optical filter OF 1 are plane surfaces.

With the above design of the lenses, stop ST 1 , and at least one of the conditions (1)-(7) satisfied, the lens assembly 1 can have an effective shortened total lens length, an effective increased field of view, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 1 shows the optical specification of the lens assembly 1 in FIG. 1 .

Table 2 shows the parameters and condition values for conditions (1)-(7) in accordance with the first embodiment of the invention. It can be seen from Table 2 that the lens assembly 1 of the first embodiment satisfies the conditions (1)-(7).

In addition, the lens assembly 1 of the first embodiment can meet the requirements of optical performance as seen in FIGS. 2 A- 2 C . It can be seen from FIG. 2 A that the longitudinal spherical aberration in the lens assembly 1 of the first embodiment ranges from −0.025 mm to 0.025 mm. It can be seen from FIG. 2 B that the astigmatic field curves of tangential direction and sagittal direction in the lens assembly 1 of the first embodiment ranges from −0.050 mm to 0.0 mm. It can be seen from FIG. 2 C that the distortion in the lens assembly 1 of the first embodiment ranges from −30% to 0%. It is obvious that the longitudinal spherical aberration, the astigmatic field curves, and the distortion of the lens assembly 1 of the first embodiment can be corrected effectively. Therefore, the lens assembly 1 of the first embodiment is capable of good optical performance.

Referring to FIG. 3 , the lens assembly 2 includes a first lens L 21 , a second lens L 22 , a third lens L 23 , a stop ST 2 , a fourth lens L 24 , a fifth lens L 25 , a sixth lens L 26 , a seventh lens L 27 , and an optical filter OF 2 , all of which are arranged in order from an object side to an image side along an optical axis OA 2 . In operation, the light from the object side is imaged on an image plane IMA 2 .

According to the foregoing, wherein: the second lens L 22 is a meniscus lens with positive refractive power, wherein the object side surface S 23 is a convex surface and the image side surface S 24 is a concave surface; the third lens L 23 is a meniscus lens with negative refractive power, wherein the object side surface S 25 is a concave surface; the fifth lens L 25 is a biconvex lens with positive refractive power, wherein the object side surface S 210 is a convex surface and the image side surface S 211 is a convex surface; the sixth lens L 26 is a biconcave lens with negative refractive power, wherein the image side surface S 213 is a concave surface; and both of the object side surface S 216 and image side surface S 217 of the optical filter OF 2 are plane surfaces.

With the above design of the lenses, stop ST 2 , and at least one of the conditions (1)-(7) satisfied, the lens assembly 2 can have an effective shortened total lens length, an effective increased field of view, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 3 shows the optical specification of the lens assembly 2 in FIG. 3 .

Table 4 shows the parameters and condition values for conditions (1)-(7) in accordance with the second embodiment of the invention. It can be seen from Table 4 that the lens assembly 2 of the second embodiment satisfies the conditions (1)-(7).

In addition, the lens assembly 2 of the second embodiment can meet the requirements of optical performance as seen in FIGS. 4 A- 4 C . It can be seen from FIG. 4 A that the longitudinal spherical aberration in the lens assembly 2 of the second embodiment ranges from −0.025 mm to 0.025 mm. It can be seen from FIG. 4 B that the astigmatic field curves of tangential direction and sagittal direction in the lens assembly 2 of the second embodiment ranges from −0.050 mm to 0.0 mm. It can be seen from FIG. 4 C that the distortion in the lens assembly 2 of the second embodiment ranges from −25% to 0%. It is obvious that the longitudinal spherical aberration, the astigmatic field curves, and the distortion of the lens assembly 2 of the second embodiment can be corrected effectively. Therefore, the lens assembly 2 of the second embodiment is capable of good optical performance.

Referring to FIG. 5 , the lens assembly 3 includes a first lens L 31 , a second lens L 32 , a third lens L 33 , a stop ST 3 , a fourth lens L 34 , a fifth lens L 35 , a sixth lens L 36 , a seventh lens L 37 , and an optical filter OF 3 , all of which are arranged in order from an object side to an image side along an optical axis OA 3 . In operation, the light from the object side is imaged on an image plane IMA 3 .

According to the foregoing, wherein: the second lens L 32 is a biconcave lens with negative refractive power, wherein the object side surface S 33 is a concave surface and the image side surface S 34 is a concave surface; the third lens L 33 is a biconvex lens with positive refractive power, wherein the object side surface S 35 is a convex surface; the fifth lens L 35 is a biconcave lens with negative refractive power, wherein the object side surface S 310 is a concave surface and the image side surface S 311 is a concave surface; the sixth lens L 36 is a meniscus lens with positive refractive power, wherein the image side surface S 313 is a convex surface; and both of the object side surface S 316 and image side surface S 317 of the optical filter OF 3 are plane surfaces.

With the above design of the lenses, stop ST 3 , and at least one of the conditions (1)-(7) satisfied, the lens assembly 3 can have an effective shortened total lens length, an effective increased field of view, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 5 shows the optical specification of the lens assembly 3 in FIG. 5 .

Table 6 shows the parameters and condition values for conditions (1)-(7) in accordance with the third embodiment of the invention. It can be seen from Table 6 that the lens assembly 3 of the third embodiment satisfies the conditions (1)-(7).

In addition, the lens assembly 3 of the third embodiment can meet the requirements of optical performance as seen in FIGS. 6 A- 6 C . It can be seen from FIG. 6 A that the longitudinal spherical aberration in the lens assembly 3 of the third embodiment ranges from −0.050 mm to 0.025 mm. It can be seen from FIG. 6 B that the astigmatic field curves of tangential direction and sagittal direction in the lens assembly 3 of the third embodiment ranges from −0.050 mm to 0.0 mm. It can be seen from FIG. 6 C that the distortion in the lens assembly 3 of the third embodiment ranges from −30% to 0%. It is obvious that the longitudinal spherical aberration, the astigmatic field curves, and the distortion of the lens assembly 3 of the third embodiment can be corrected effectively. Therefore, the lens assembly 3 of the third embodiment is capable of good optical performance.

Referring to FIG. 7 , the lens assembly 4 includes a first lens L 41 , a second lens L 42 , a third lens L 43 , a stop ST 4 , a fourth lens L 44 , a fifth lens L 45 , a sixth lens L 46 , a seventh lens L 47 , and an optical filter OF 4 , all of which are arranged in order from an object side to an image side along an optical axis OA 4 . In operation, the light from the object side is imaged on an image plane IMA 4 .

According to the foregoing, wherein: the second lens L 42 is a meniscus lens with negative refractive power, wherein the object side surface S 43 is a convex surface and the image side surface S 44 is a concave surface; the third lens L 43 is a biconvex lens with positive refractive power, wherein the object side surface S 45 is a convex surface; the fifth lens L 45 is a biconcave lens with negative refractive power, wherein the object side surface S 410 is a concave surface and the image side surface S 411 is a concave surface; the sixth lens L 46 is a meniscus lens with positive refractive power, wherein the image side surface S 413 is a convex surface; and both of the object side surface S 416 and image side surface S 417 of the optical filter OF 4 are plane surfaces.

With the above design of the lenses, stop ST 4 , and at least one of the conditions (1)-(7) satisfied, the lens assembly 4 can have an effective shortened total lens length, an effective increased field of view, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 7 shows the optical specification of the lens assembly 4 in FIG. 7 .

Table 8 shows the parameters and condition values for conditions (1)-(7) in accordance with the fourth embodiment of the invention. It can be seen from Table 8 that the lens assembly 4 of the fourth embodiment satisfies the conditions (1)-(7).

In addition, the lens assembly 4 of the fourth embodiment can meet the requirements of optical performance as seen in FIGS. 8 A- 8 C . It can be seen from FIG. 8 A that the longitudinal spherical aberration in the lens assembly 4 of the fourth embodiment ranges from −0.050 mm to 0.025 mm. It can be seen from FIG. 8 B that the astigmatic field curves of tangential direction and sagittal direction in the lens assembly 4 of the fourth embodiment ranges from −0.075 mm to 0.0 mm. It can be seen from FIG. 8 C that the distortion in the lens assembly 4 of the fourth embodiment ranges from −80% to 0%. It is obvious that the longitudinal spherical aberration, the astigmatic field curves, and the distortion of the lens assembly 4 of the fourth embodiment can be corrected effectively. Therefore, the lens assembly 4 of the fourth embodiment is capable of good optical performance.

Referring to Table 9, Table 10, Table 12, Table 13, Table 15, and Table 16, wherein Table 9, Table 12, and Table 15 show respectively optical specification in accordance with a fifth, sixth, and seventh embodiments of the invention and Table 10, Table 13, and Table 16 show respectively aspheric coefficients of each aspheric lens in Table 9, Table 12, and Table 15.

FIG. 9 , FIG. 11 , and FIG. 13 are lens layout diagrams of the lens assemblies in accordance with the fifth, sixth, and seventh embodiments of the invention, respectively.

The first lenses L 51 , L 61 , L 71 are meniscus lenses with negative refractive power and made of glass material, wherein the object side surfaces S 51 , S 61 , S 71 are convex surfaces, the image side surfaces S 52 , S 62 , S 72 are concave surfaces, and both of the object side surfaces S 51 , S 61 , S 71 and image side surfaces S 52 , S 62 , S 72 are spherical surfaces.

The second lenses L 52 , L 62 , L 72 are meniscus lenses with negative refractive power and made of plastic material, wherein the object side surfaces S 53 , S 63 , S 73 are concave surfaces, the image side surfaces S 54 , S 64 , S 74 are convex surfaces, and both of the object side surfaces S 53 , S 63 , S 73 and image side surfaces S 54 , S 64 , S 74 are aspheric surfaces.

The third lenses L 53 , L 63 , L 73 are biconvex lenses with positive refractive power and made of glass material, wherein the object side surfaces S 55 , S 65 , S 75 are convex surfaces, the image side surfaces S 56 , S 66 , S 76 are convex surfaces, and both of the object side surfaces S 55 , S 65 , S 75 and image side surfaces S 56 , S 66 S 76 are spherical surfaces.

The fourth lenses L 54 , L 64 , L 74 are meniscus lenses with positive refractive power and made of glass material, wherein the object side surfaces S 58 , S 68 , S 78 are concave surfaces, the image side surfaces S 59 , S 69 , S 79 are convex surfaces, and both of the object side surfaces S 58 S 68 , S 78 and image side surfaces S 59 , S 69 , S 79 are spherical surfaces.

The fifth lenses L 55 , L 65 , L 75 are meniscus lenses with positive refractive power and made of plastic material, wherein the object side surfaces S 510 , S 610 . S 710 are convex surfaces, the image side surfaces S 511 S 611 , S 711 are concave surfaces, and both of the object side surfaces S 510 , S 610 , S 710 and image side surfaces S 511 , S 611 , S 711 are aspheric surfaces.

The sixth lenses L 56 , L 66 , L 76 are meniscus lenses with positive refractive power and made of plastic material, wherein the object side surfaces S 512 , S 612 , S 712 are concave surfaces, the image side surfaces S 513 , S 613 , S 713 are convex surfaces, and both of the object side surfaces S 512 , S 612 , S 712 and image side surfaces S 513 , S 613 , S 713 are aspheric surfaces.

The seventh lenses L 57 , L 67 , L 77 are with positive refractive power and made of glass material, wherein the object side surfaces S 514 , S 614 , S 714 are convex surfaces and both of the object side surfaces S 514 , S 614 , S 714 and image side surfaces S 515 , S 615 , S 715 are spherical surfaces.

In addition, the lens assemblies 5 , 6 , 7 satisfy at least one of the condition 1 and the following conditions:

0.7< f 3 /f 7 <1.1;  (8)

0.5<Gap23/Gap67<0.75;  (9)

−2< R 42 /R 51 <−0.8;  (10)

wherein f 3 is an effective focal length of the third lenses L 53 , L 63 , L 73 for the fifth to seventh embodiments, f 7 is an effective focal length of the seventh lenses L 57 , L 67 , L 77 for the fifth to seventh embodiments, Gap23 is respectively an interval from the image side surfaces S 54 , S 64 , S 74 of the second lenses L 52 , L 62 , L 72 to the object side surfaces S 55 , S 65 , S 75 of the third lenses L 53 , L 63 , L 73 along the optical axes OA 5 , OA 6 , OA 7 for the fifth to seventh embodiments, Gap67 is respectively an interval from the image side surfaces S 513 , S 613 , S 713 of the sixth lenses L 56 L 66 , L 76 to the object side surfaces S 514 , S 614 , S 714 of the seventh lenses L 57 , L 67 , L 77 along the optical axes OA 5 , OA 6 , OA 7 for the fifth to seventh embodiments, R 42 is a radius of curvature of the image side surfaces S 59 , S 69 , S 79 of the fourth lenses L 54 , L 64 , L 74 for the fifth to seventh embodiments, and R 51 is a radius of curvature of the object side surfaces S 510 , S 610 , S 710 of the fifth lenses L 55 , L 65 , L 75 for the fifth to seventh embodiments. With the lens assemblies 5 , 6 , 7 , satisfying at least one of the above conditions (1), (8)-(10), the total lens length can be effectively shortened, the F-number can be effectively decreased, the resolution can be effectively increased, the environmental temperature change can be effectively resisted, the aberration can be effectively corrected, and the chromatic aberration can be effectively corrected.

When the condition (1): 0.7<f/IH<1.5 is satisfied, the field of view of the lens assembly can be effectively increased.

When the condition (9): 0.5<Gap23/Gap67<0.75 is satisfied, the total lens length of the lens assembly can be effectively shortened.

When the condition (10): −2<R 42 /R 51 <−0.8 is satisfied, the spherical aberration of the lens assembly can be effectively corrected.

A detailed description of a lens assembly in accordance with a fifth embodiment of the invention is as follows. Referring to FIG. 9 , the lens assembly 5 includes a first lens L 51 , a second lens L 52 , a third lens L 53 , a stop ST 5 , a fourth lens L 54 , a fifth lens L 55 , a sixth lens L 56 , a seventh lens L 57 , an optical filter OF 5 , and a cover glass CG 5 , all of which are arranged in order from an object side to an image side along an optical axis OA 5 . In operation, the light from the object side is imaged on an image plane IMA 5 .

According to the foregoing, wherein: the seventh lens is a biconvex lens, wherein the image side surface S 515 is a convex surface; both of the object side surface S 516 and image side surface S 517 of the optical filter OF 5 are plane surfaces; and both of the object side surface S 518 and image side surface S 519 of the cover glass CG 5 are plane surfaces.

With the above design of the lenses, stop ST 5 and at least one of the conditions (1), (8)-(10) satisfied, the lens assembly 5 can have an effective shortened total lens length, an effective decreased F-number, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 9 shows the optical specification of the lens assembly 5 in FIG. 9 .

The aspheric surface sag z of each aspheric lens in table 9 can be calculated by the following formula:

z=ch 2 /{1+[1−( k+ 1) c 2 h 2 ] 1/2 }+Ah 4 +Bh 6 +Ch 8 +Dh 10

where c is curvature, h is the vertical distance from the lens surface to the optical axis, k is conic constant and A, B, C, and D are aspheric coefficients.

In the fifth embodiment, the conic constant k and the aspheric coefficients A, B, C, D of each aspheric lens are shown in Table 10.

Table 11 shows the parameters and condition values for conditions (1), (8)-(10) in accordance with the fifth embodiment of the invention. It can be seen from Table 11 that the lens assembly 5 of the fifth embodiment satisfies the conditions (1), (8)-(10).

In addition, the lens assembly 5 of the fifth embodiment can meet the requirements of optical performance as seen in FIGS. 10 A- 10 C . It can be seen from FIG. 10 A that the longitudinal aberration in the lens assembly 5 of the fifth embodiment ranges from −0.025 mm to 0.025 mm. It can be seen from FIG. 10 B that the field curvature of tangential direction and sagittal direction in the lens assembly 5 of the fifth embodiment ranges from −0.025 mm to 0.05 mm. It can be seen from FIG. 10 C that the distortion in the lens assembly 5 of the fifth embodiment ranges from −70% to 4%. It is obvious that the longitudinal aberration, the field curvature, and the distortion of the lens assembly 5 of the fifth embodiment can be corrected effectively. Therefore, the lens assembly 5 of the fifth embodiment is capable of good optical performance.

Referring to FIG. 11 , the lens assembly 6 includes a first lens L 61 , a second lens L 62 , a third lens L 63 , a stop ST 6 , a fourth lens L 64 , a fifth lens L 65 , a sixth lens L 66 , a seventh lens L 67 , an optical filter OF 6 , and a cover glass CG 6 , all of which are arranged in order from an object side to an image side along an optical axis OA 6 . In operation, the light from the object side is imaged on an image plane IMA 6 .

According to the foregoing, wherein: the seventh lens is a meniscus lens, wherein the image side surface S 615 is a concave surface; both of the object side surface S 616 and image side surface S 617 of the optical filter OF 6 are plane surfaces; and both of the object side surface S 618 and image side surface S 619 of the cover glass CG 6 are plane surfaces.

With the above design of the lenses, stop ST 6 , and at least one of the conditions (1), (8)-(10) satisfied, the lens assembly 6 can have an effective shortened total lens length, an effective decreased F-number, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 12 shows the optical specification of the lens assembly 6 in FIG. 11 .

The definition of aspheric surface sag z of each aspheric lens in table 12 is the same as that of in Table 9, and is not described here again.

In the sixth embodiment, the conic constant k and the aspheric coefficients A, B, C, D of each aspheric lens are shown in Table 13.

Table 14 shows the parameters and condition values for conditions (1), (8)-(10) in accordance with the sixth embodiment of the invention. It can be seen from Table 14 that the lens assembly 6 of the sixth embodiment satisfies the conditions (1), (8)-(10).

In addition, the lens assembly 6 of the sixth embodiment can meet the requirements of optical performance as seen in FIGS. 12 A- 12 C . It can be seen from FIG. 12 A that the longitudinal aberration in the lens assembly 6 of the sixth embodiment ranges from −0.025 mm to 0.025 mm. It can be seen from FIG. 12 B that the field curvature of tangential direction and sagittal direction in the lens assembly 6 of the sixth embodiment ranges from −0.03 mm to 0.06 mm. It can be seen from FIG. 12 C that the distortion in the lens assembly 6 of the sixth embodiment ranges from −70% to 0%. It is obvious that the longitudinal aberration, the field curvature, and the distortion of the lens assembly 6 of the sixth embodiment can be corrected effectively. Therefore, the lens assembly 6 of the sixth embodiment is capable of good optical performance.

Referring to FIG. 13 , the lens assembly 7 includes a first lens L 71 , a second lens L 72 , a third lens L 73 , a stop ST 7 , a fourth lens L 74 , a fifth lens L 75 , a sixth lens L 76 , a seventh lens L 77 , an optical filter OF 7 , and a cover glass CG 7 all of which are arranged in order from an object side to an image side along an optical axis OA 7 . In operation, the light from the object side is imaged on an image plane IMA 7 .

According to the foregoing, wherein: the seventh lens L 77 is a biconvex lens, wherein the image side surface S 715 is a convex surface; both of the object side surface S 716 and image side surface S 717 of the optical filter OF 7 are plane surfaces; and both of the object side surface S 718 and image side surface S 719 of the cover glass CG 7 are plane surfaces.

With the above design of the lenses, stop ST 7 , and at least one of the conditions (1), (8)-(10) satisfied, the lens assembly 7 can have an effective shortened total lens length, an effective decreased F-number, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 15 shows the optical specification of the lens assembly 7 in FIG. 13 .

The definition of aspheric surface sag z of each aspheric lens in table 15 is the same as that of in Table 9, and is not described here again.

In the seventh embodiment, the conic constant k and the aspheric coefficients A, B, C. D of each aspheric lens are shown in Table 16.

Table 17 shows the parameters and condition values for conditions (1), (8)-(10) in accordance with the seventh embodiment of the invention. It can be seen from Table 17 that the lens assembly 7 of the seventh embodiment satisfies the conditions (1), (8)-(10).

In addition, the lens assembly 7 of the seventh embodiment can meet the requirements of optical performance as seen in FIGS. 14 A- 14 C . It can be seen from FIG. 14 A that the longitudinal aberration in the lens assembly 7 of the seventh embodiment ranges from −0.03 mm to 0.03 mm. It can be seen from FIG. 14 B that the field curvature of tangential direction and sagittal direction in the lens assembly 7 of the seventh embodiment ranges from −0.03 mm to 0.06 mm. It can be seen from FIG. 14 C that the distortion in the lens assembly 7 of the seventh embodiment ranges from −70% to 0%. It is obvious that the longitudinal aberration, the field curvature, and the distortion of the lens assembly 7 of the seventh embodiment can be corrected effectively. Therefore, the lens assembly 7 of the seventh embodiment is capable of good optical performance.

While the invention has been described by way of example and in terms of the preferred embodiment(s), it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.