Lens Assembly

A lens assembly includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens is with positive refractive power and includes a convex surface facing an object side. The second lens is with negative refractive power. The third lens is a biconvex lens with positive refractive power and includes a convex surface facing the object side and another convex surface facing an image side. The fourth lens is with negative refractive power. The fifth lens is with positive refractive power. The sixth lens is with positive refractive power and includes a convex surface facing the image side. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are arranged in order from the object side to the image side along an optical axis.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates to a lens assembly.

Description of the Related Art

The current development trend of a lens assembly is toward miniaturization and high resolution. Additionally, the lens assembly is developed to resist 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 resisted environmental temperature change at the same time.

BRIEF SUMMARY OF THE INVENTION

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, a decreased F-number, 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, and a sixth lens. The first lens is with positive refractive power and includes a convex surface facing an object side. The second lens is with negative refractive power. The third lens is a biconvex lens with positive refractive power and includes a convex surface facing the object side and another convex surface facing an image side. The fourth lens is with negative refractive power. The fifth lens is with positive refractive power. The sixth lens is with positive refractive power and includes a convex surface facing the image side. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are arranged in order from the object side to the image side along an optical axis. The lens assembly satisfies: 2.5<TTL/f<4.75; wherein TTL is an interval from an object side surface of the first lens to an image plane along the optical axis and f is an effective focal length of the lens assembly.

In another exemplary embodiment, the second lens includes a concave surface facing the image side, the fourth lens is a biconcave lens and includes a concave surface facing the object side and another concave surface facing the image side, and the fifth lens is a biconvex lens and includes a convex surface facing the object side and another convex surface facing the image side.

In yet another exemplary embodiment, the lens assembly further includes a seventh lens disposed between the sixth lens and the image side, wherein the first lens is a meniscus lens and further includes a concave surface facing the image side, and the seventh 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 another exemplary embodiment, the second lens is a meniscus lens and further includes a convex surface facing the object side, and the sixth lens is a biconvex lens and further includes another convex surface facing the object side.

In yet another exemplary embodiment, the lens assembly satisfies: 3<TTL/BFL<6.8; −9.3<(R11+R12)/(R11−R12)<−0.2; 2<|f45/f|<6.5; −1<f4/f5<0; 20<Vd5−Vd4<40; −7<R32/R31<−0.2; wherein TTL is an interval from the object side surface of the first lens to the image plane along the optical axis, BFL is an interval from an image side surface of the lens closest to the image side to the image plane along the optical axis, R11is a radius of curvature of the object side surface of the first lens, R12is a radius of curvature of an image side surface of the first lens, f45 is an effective focal length of a combination of the fourth lens and the fifth lens, f is an effective focal length of the lens assembly, f4 is an effective focal length of the fourth lens, f5 is an effective focal length of the fifth lens, Vd4is an Abbe number of the fourth lens, Vd5is an Abbe number of the fifth lens, R31is a radius of curvature of an object side surface of the third lens, and R32is a radius of curvature of an image side surface of the third lens.

In another exemplary embodiment, the lens assembly further includes an eighth lens disposed between the seventh lens and the image side, wherein the sixth lens is a meniscus lens and further includes a concave surface facing the object side, and the eighth lens is a meniscus lens with positive refractive power and includes a convex surface facing the object side and a concave surface facing the image side.

In yet another exemplary embodiment, the lens assembly satisfies: 0.25<Nd6−Nd7<0.33; wherein Nd6is an index of refraction of the sixth lens and Nd7is an index of refraction of the seventh lens.

In another exemplary embodiment, the lens assembly satisfies: 1.0<Vd7/Vd6<1.5; wherein Vd6is an Abbe number of the sixth lens and Vd7is an Abbe number of the seventh lens.

In yet another exemplary embodiment, the first lens is a biconvex lens and further includes another convex surface facing the image side, and the sixth lens is a biconvex lens and further includes another convex surface facing the object side.

In another exemplary embodiment, the fourth lens and the fifth lens are cemented, and the sixth lens is an aspheric lens.

In yet another exemplary embodiment, the lens assembly further includes a stop disposed between the second lens and the fourth lens.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a lens assembly including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens is with positive refractive power and includes a convex surface facing an object side. The second lens is with negative refractive power. The third lens is a biconvex lens with positive refractive power and includes a convex surface facing the object side and another convex surface facing an image side. The fourth lens is with negative refractive power. The fifth lens is with positive refractive power. The sixth lens is with positive refractive power and includes a convex surface facing the image side. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are arranged in order from the object side to the image side along an optical axis. The lens assembly satisfies: 2.5<TTL/f<4.75; wherein TTL is an interval from an object side surface of the first lens to an image plane along the optical axis and f is an effective focal length of the lens assembly.

Referring to Table 1, Table 2, Table 4, Table 5, Table 7, Table 8, Table 10, Table 11, Table 13, Table 14, Table 16, Table 17, Table 19, Table 21, and Table 22, wherein Table 1, Table 4, Table 7, Table 10, Table 13, Table 16, Table 19, and Table 21 show optical specification in accordance with a first, second, third, fourth, fifth, sixth, seventh, and eighth embodiments of the invention, respectively and Table 2, Table 5, Table 8, Table 11, Table 14, Table 17, and Table 22 show aspheric coefficients of each aspheric lens in Table 1, Table 4, Table 7, Table 10, Table 13, Table 16, and Table 21, respectively.FIG. 1,FIG. 3,FIG. 4,FIG. 6,FIG. 7,FIG. 8,FIG. 9, andFIG. 11are lens layout and optical path diagrams of the lens assemblies in accordance with the first, second, third, fourth, fifth, sixth, seventh, and eighth embodiments of the invention, respectively.

In addition, the lens assemblies1,2,3,4,5,6satisfy at least one of the following conditions (1)-(7) and the lens assemblies7,8satisfy at least one of the following conditions (1)-(9):

wherein TTL is an interval from the object side surfaces S11, S21, S31, S41, S51, S61, S71, S81of the first lenses L11, L21, L31, L41, L51, L61, L71, L81to the image planes IMA1, IMA2, IMA3, IMA4, IMA5, IMA6, IMA7, IMA8along the optical axes OA1, OA2, OA3, OA4, OA5, OA6, OA7, OA8for the first to eighth embodiments, respectively, BFL is an interval from the image side surfaces S112, S212, S312, S412, S512, S612, S715, S817of the lenses L16, L26, L36, L46, L56, L66, L77, L88closest to the image side to the image planes IMA1, IMA2, IMA3, IMA4, IMA5, IMA6, IMA7, IMA8along the optical axes OA1, OA2, OA3, OA4, OAS, OA6, OA7, OA8for the first to eighth embodiments, respectively, f is an effective focal length of the lens assemblies1,2,3,4,5,6,7,8for the first to eighth embodiments, f4 is an effective focal length of the fourth lenses L14, L24, L34, L44, L54, L64, L74, L84for the first to eighth embodiments, f5 is an effective focal length of the fifth lenses L15, L25, L35, L45, L55, L65, L75, L85for the first to eighth embodiments, f45 is an effective focal length of the combination of the fourth lenses L14, L24, L34, L44, L54, L64, L74, L84and the fifth lenses L15, L25, L35, L45, L55, L65, L75, L85for the first to eighth embodiments, R11is a radius of curvature of the object side surfaces S11, S21, S31, S41, S51, S61, S71, S81of the first lenses L11, L21, L31, L41, L51, L61, L71, L81for the first to eighth embodiments, R12is a radius of curvature of the image side surfaces S12, S22, S32, S42, S52, S62, S72, S82of the first lenses L11, L21, L31, L41, L51, L61, L71, L81for the first to eighth embodiments, R31is a radius of curvature of the object side surfaces S16, S26, S36, S46, S56, S66, S75, S85of the third lenses L13, L23, L33, L43, L53, L63, L73, L83for the first to eighth embodiments, R32is a radius of curvature of the image side surfaces S17, S27, S37, S47, S57, S67, S76, S86of the third lenses L13, L23, L33, L43, L53, L63, L73, L83for the first to eighth embodiments, Vd4is an Abbe number of the fourth lenses L14, L24, L34, L44, L54, L64, L74, L84for the first to eighth embodiments, Vd5is an Abbe number of the fifth lenses L15, L25, L35, L45, L55, L65, L75, L85for the first to eighth embodiments, Vd6is an Abbe number of the sixth lenses L76, L86for the seventh to eighth embodiments, Vd7is an Abbe number of the seventh lenses L77, L87for the seventh to eighth embodiments, Nd6is an index of refraction of the sixth lenses L76, L86for the seventh to eighth embodiments, and Nd7is an index of refraction of the seventh lenses L77, L87for the seventh to eighth embodiments. With the lens assemblies1,2,3,4,5,6,7,8satisfying at least one of the above conditions (1)-(9), the total lens length can be effectively shortened, 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): 2.50<TTL/f<4.75 is satisfied, the total lens length can be effectively decreased.

When the condition (2): 3<TTL/BFL<6.8 is satisfied, the back focal length can be effectively increased to facilitate the assembly of the lens assembly, and can reserve space to install additional reflective element or other application element.

When the condition (3): −9.3<(R11+R12)/(R11−R12)<−0.2 is satisfied, the first lens can be ensured to have positive refractive power and is a biconvex lens.

When the condition (4): 2<|f45/f<6.5 is satisfied, the chromatic aberration can be effectively decreased and the image quality can be greatly improved.

When the condition (5): −1<f4/f5<0 is satisfied, the processing sensitivity can be effectively decreased and the image quality can be improved.

When the condition (6): 20<Vd5−Vd4<40 is satisfied, the chromatic aberration can be effectively decreased and the image quality can be improved.

When the condition (7): −7<R32/R31<−0.2 is satisfied, the sensitivity of the third lens can be effectively decreased and the image quality can be improved.

When the condition (8): 1.0<Vd7/Vd6<1.5 is satisfied, the chromatic aberration can be effectively decreased and the image quality can be improved.

When the condition (9): 0.25<Nd6−Nd7<0.33 is satisfied, the image quality can be effectively improved.

The optical path can be effectively adjusted so that it is not easy to have a big turn when the first lens has positive refractive power and is a biconvex lens.

The spherical aberration caused by the first lens being a biconvex lens can be effectively decreased when the second lens has negative refractive power and is a biconcave lens, and the distortion can be effectively decreased when the first lens has positive refractive power and the second lens has negative refractive power.

The total lens length can be effectively decreased when the third lens is a biconvex lens with positive refractive power.

The axial and lateral chromatic aberration can be effectively decreased and the resolution can be effectively improved when the fourth lens and the fifth lens are cemented.

The incident angle of chief ray can be adjusted significantly and the back focal length can be effectively increased thereby facilitates the assembly of the lens assembly when the sixth lens is an aspheric lens with positive refractive power.

A detailed description of a lens assembly in accordance with a first embodiment of the invention is as follows. Referring toFIG. 1, the lens assembly1includes a first lens L11, a second lens L12, a stop ST1, a third lens L13, a fourth lens L14, a fifth lens L15, a sixth lens L16, and a cover glass CG1, all of which are arranged in order from an object side to an image side along an optical axis OA1. In operation, the light from the object side is imaged on an image plane IMA1.

According to paragraphs [0030]-[0037], wherein: the first lens L11is a biconvex lens, wherein the image side surface S12is a convex surface; the second lens L12is a biconcave lens, wherein the object side surface S13is a concave surface; both of the object side surface S19and image side surface S110of the fifth lens L15are spherical surfaces; the sixth lens L16is a biconvex lens, wherein the object side surface S111is a convex surface, and both of the object side surface S111and image side surface S112are aspheric surfaces; the fourth lens L14and the fifth lens L15are cemented; and both of the object side surface S113and image side surface S114of the cover glass CG1are plane surfaces.

With the above design of the lenses, stop ST1, and at least one of the conditions (1)-(7) satisfied, the lens assembly1can have an effective shortened total lens length, 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 assembly1inFIG. 1.

The aspheric surface sag z of each aspheric lens in table 1 can be calculated by the following formula:

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, D, E, F, and G are aspheric coefficients.

In the first embodiment, the conic constant k and the aspheric coefficients A, B, C, D, E, F, G of each aspheric lens are shown in Table 2.

Table 3 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 3 that the lens assembly1of the first embodiment satisfies the conditions (1)-(7).

In addition, the lens assembly1of the first embodiment can meet the requirements of optical performance as seen inFIGS. 2A-2D. It can be seen fromFIG. 2Athat the field curvature of tangential direction and sagittal direction in the lens assembly1of the first embodiment ranges from −0.04 mm to 0.04 mm. It can be seen fromFIG. 2Bthat the distortion in the lens assembly1of the first embodiment ranges from −5% to 0%. It can be seen fromFIG. 2Cthat the root mean square spot radius is equal to 2.816 μm and geometrical spot radius is equal to 6.097 μm as image height is equal to 0.000 mm, the root mean square spot radius is equal to 3.706 μm and geometrical spot radius is equal to 10.970 μm as image height is equal to 2.184 mm, the root mean square spot radius is equal to 3.454 μm and geometrical spot radius is equal to 10.177 μm as image height is equal to 3.277 mm, the root mean square spot radius is equal to 2.511 μm and geometrical spot radius is equal to 8.086 μm as image height is equal to 4,369 mm, and the root mean square spot radius is equal to 4.233 μm and geometrical spot radius is equal to 12.837 μm as image height is equal to 5.461 mm for the lens assembly1of the first embodiment. It can be seen fromFIG. 2Dthat the modulation transfer function of tangential direction and sagittal direction in the lens assembly1of the first embodiment ranges from 0.67 to 1.0. It is obvious that the field curvature and the distortion of the lens assembly1of the first embodiment can be corrected effectively, and the resolution of the lens assembly1of the first embodiment can meet the requirement. Therefore, the lens assembly1of the first embodiment is capable of good optical performance.

Referring toFIG. 3, the lens assembly2includes a first lens L21, a second lens L22, a stop ST2, a third lens L23, a fourth lens L24, a fifth lens L25, a sixth lens L26, and a cover glass CG2, all of which are arranged in order from an object side to an image side along an optical axis OA2. In operation, the light from the object side is imaged on an image plane IMA2.

According to paragraphs [0030]-[0037], wherein: the first lens L21is a biconvex lens, wherein the image side surface S22is a convex surface; the second lens L22is a biconcave lens, wherein the object side surface S23is a concave surface; both of the object side surface S29and image side surface S210of the fifth lens L25are spherical surfaces; the sixth lens L26is a biconvex lens, wherein the object side surface S211is a convex surface, and both of the object side surface S211and image side surface S212are aspheric surfaces; the fourth lens L24and the fifth lens L25are cemented; and both of the object side surface S213and image side surface S214of the cover glass CG2are plane surfaces.

With the above design of the lenses, stop ST2, and at least one of the conditions (1)-(7) satisfied, the lens assembly2can have an effective shortened total lens length, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 4 shows the optical specification of the lens assembly2inFIG. 3.

The definition of aspheric surface sag z of each aspheric lens in table 4 is the same as that of in Table 1, and is not described here again.

In the second embodiment, the conic constant k and the aspheric coefficients A, B, C, D, E, F, G of each aspheric lens are shown in Table 5.

Table 6 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 5 that the lens assembly2of the second embodiment satisfies the conditions (1)-(7).

In addition, the lens assembly2of the second embodiment can meet the requirements of optical performance, wherein the field curvature diagram, the distortion diagram, the spot diagram, and the modulation transfer function diagram are similar to those of the lens assembly1of the first embodiment, so that those figures are omitted.

Referring toFIG. 4, the lens assembly3includes a first lens L31, a second lens L32, a stop ST3, a third lens L33, a fourth lens L34, a fifth lens L35, a sixth lens L36, and a cover glass CG3, all of which are arranged in order from an object side to an image side along an optical axis OA3. In operation, the light from the object side is imaged on an image plane IMA3.

According to paragraphs [0030]-[0037], wherein: the first lens L31is a biconvex lens, wherein the image side surface S32is a convex surface; the second lens L32is a biconcave lens, wherein the object side surface S33is a concave surface; both of the object side surface S39and image side surface S310of the fifth lens L35are spherical surfaces; the sixth lens L36is a biconvex lens, wherein the object side surface S311is a convex surface, and both of the object side surface S311and image side surface S312are aspheric surfaces; the fourth lens L34and the fifth lens L35are cemented; and both of the object side surface S313and image side surface S314of the cover glass CG3are plane surfaces.

With the above design of the lenses, stop ST3, and at least one of the conditions (1)-(7) satisfied, the lens assembly3can have an effective shortened total lens length, 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 assembly3inFIG. 4.

The definition of aspheric surface sag z of each aspheric lens in table 7 is the same as that of in Table 1, and is not described here again.

In the third embodiment, the conic constant k and the aspheric coefficients A, B, C, D, E, F, G of each aspheric lens are shown in Table 8.

Table 9 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 9 that the lens assembly3of the third embodiment satisfies the conditions (1)-(7).

In addition, the lens assembly3of the third embodiment can meet the requirements of optical performance as seen inFIGS. 5A-5D. It can be seen fromFIG. 5Athat the field curvature of tangential direction and sagittal direction in the lens assembly3of the third embodiment ranges from −0.04 mm to 0.05 mm. It can be seen fromFIG. 5Bthat the distortion in the lens assembly3of the third embodiment ranges from −5% to 0%. It can be seen fromFIG. 5Cthat the root mean square spot radius is equal to 1.489 μm and geometrical spot radius is equal to 3.613 μm as image height is equal to 0.000 mm, the root mean square spot radius is equal to 2.292 μm and geometrical spot radius is equal to 6.685 μm as image height is equal to 2.184 mm, the root mean square spot radius is equal to 2.264 μm and geometrical spot radius is equal to 6.491 μm as image height is equal to 3.277 mm, the root mean square spot radius is equal to 2.263 μm and geometrical spot radius is equal to 6.113 μm as image height is equal to 4,369 mm, and the root mean square spot radius is equal to 4.647 μm and geometrical spot radius is equal to 14.046 μm as image height is equal to 5.461 mm for the lens assembly3of the third embodiment. It can be seen fromFIG. 5Dthat the modulation transfer function of tangential direction and sagittal direction in the lens assembly 3 of the third embodiment ranges from 0.68 to 1.0. It is obvious that the field curvature and the distortion of the lens assembly3of the third embodiment can be corrected effectively, and the resolution of the lens assembly3of the third embodiment can meet the requirement. Therefore, the lens assembly3of the third embodiment is capable of good optical performance.

Referring toFIG. 6, the lens assembly4includes a first lens L41, a second lens L42, a stop ST4, a third lens L43, a fourth lens L44, a fifth lens L45, a sixth lens L46, and a cover glass CG4, all of which are arranged in order from an object side to an image side along an optical axis OA4. In operation, the light from the object side is imaged on an image plane IMA4.

According to paragraphs [0030]-[0037], wherein: the first lens L41is a biconvex lens, wherein the image side surface S42is a convex surface; the second lens L42is a biconcave lens, wherein the object side surface S43is a concave surface; both of the object side surface S49and image side surface S410of the fifth lens L45are spherical surfaces; the sixth lens L46is a biconvex lens, wherein the object side surface S411is a convex surface, and both of the object side surface S411and image side surface S412are aspheric surfaces; the fourth lens L44and the fifth lens L45are cemented; and both of the object side surface S413and image side surface S414of the cover glass CG4are plane surfaces.

With the above design of the lenses, stop ST4, and at least one of the conditions (1)-(7) satisfied, the lens assembly4can have an effective shortened total lens length, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 10 shows the optical specification of the lens assembly4inFIG. 6.

The definition of aspheric surface sag z of each aspheric lens in table 10 is the same as that of in Table 1, and is not described here again.

In the fourth embodiment, the conic constant k and the aspheric coefficients A, B, C, D, E, F, G of each aspheric lens are shown in Table 11.

Table 12 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 12 that the lens assembly4of the fourth embodiment satisfies the conditions (1)-(7).

In addition, the lens assembly4of the fourth embodiment can meet the requirements of optical performance, wherein the field curvature diagram, the distortion diagram, the spot diagram, and the modulation transfer function diagram are similar to those of the lens assembly1of the first embodiment, so that those figures are omitted.

Referring toFIG. 7, the lens assembly5includes a first lens L51, a second lens L52, a stop STS, a third lens L53, a fourth lens L54, a fifth lens L55, a sixth lens L56, and a cover glass CGS, all of which are arranged in order from an object side to an image side along an optical axis OAS. In operation, the light from the object side is imaged on an image plane IMA5.

According to paragraphs [0030]-[0037], wherein: the first lens L51is a biconvex lens, wherein the image side surface S52is a convex surface; the second lens L52is a biconcave lens, wherein the object side surface S53is a concave surface; both of the object side surface S59and image side surface S510of the fifth lens L55are spherical surfaces; the sixth lens L56is a biconvex lens, wherein the object side surface S511is a convex surface, and both of the object side surface S511and image side surface S512are aspheric surfaces; the fourth lens L54and the fifth lens L55are cemented; and both of the object side surface S513and image side surface S514of the cover glass CGS are plane surfaces.

With the above design of the lenses, stop ST5, and at least one of the conditions (1)-(7) satisfied, the lens assembly5can have an effective shortened total lens length, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 13 shows the optical specification of the lens assembly5inFIG. 7.

The definition of aspheric surface sag z of each aspheric lens in table 13 is the same as that of in Table 1, and is not described here again.

In the fifth embodiment, the conic constant k and the aspheric coefficients A, B, C, D, E, F, G of each aspheric lens are shown in Table 14.

Table 15 shows the parameters and condition values for conditions (1)-(7) in accordance with the fifth embodiment of the invention. It can be seen from Table 15 that the lens assembly5of the fifth embodiment satisfies the conditions (1)-(7).

In addition, the lens assembly5of the fifth embodiment can meet the requirements of optical performance, wherein the field curvature diagram, the distortion diagram, the spot diagram, and the modulation transfer function diagram are similar to those of the lens assembly1of the first embodiment, so that those figures are omitted.

Referring toFIG. 8, the lens assembly6includes a first lens L61, a second lens L62, a stop ST6, a third lens L63, a fourth lens L64, a fifth lens L65, a sixth lens L66, and a cover glass CG6, all of which are arranged in order from an object side to an image side along an optical axis OA6. In operation, the light from the object side is imaged on an image plane IMA6.

According to paragraphs [0030]-[0037], wherein: the first lens L61is a biconvex lens, wherein the image side surface S62is a convex surface; the second lens L62is a biconcave lens, wherein the object side surface S63is a concave surface; both of the object side surface S69and image side surface S610of the fifth lens L65are spherical surfaces; the sixth lens L66is a biconvex lens, wherein the object side surface S611is a convex surface, and both of the object side surface S611and image side surface S612are aspheric surfaces; the fourth lens L64and the fifth lens L65are cemented; and both of the object side surface S613and image side surface S614of the cover glass CG6are plane surfaces.

With the above design of the lenses, stop ST6, and at least one of the conditions (1)-(7) satisfied, the lens assembly6can have an effective shortened total lens length, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 16 shows the optical specification of the lens assembly6inFIG. 8.

The definition of aspheric surface sag z of each aspheric lens in table 16 is the same as that of in Table 1, and is not described here again.

In the sixth embodiment, the conic constant k and the aspheric coefficients A, B, C, D, E, F, G of each aspheric lens are shown in Table 17.

Table 18 shows the parameters and condition values for conditions (1)-(7) in accordance with the sixth embodiment of the invention. It can be seen from Table 18 that the lens assembly6of the sixth embodiment satisfies the conditions (1)-(7).

In addition, the lens assembly6of the sixth embodiment can meet the requirements of optical performance, wherein the field curvature diagram, the distortion diagram, the spot diagram, and the modulation transfer function diagram are similar to those of the lens assembly1of the first embodiment, so that those figures are omitted.

Referring toFIG. 9, the lens assembly7includes a first lens L71, a second lens L72, a third lens L73, a stop ST7, a fourth lens L74, a fifth lens L75, a sixth lens L76, a seventh lens L77, an optical filter OF7, and a cover glass CG7, all of which are arranged in order from an object side to an image side along an optical axis OA7. In operation, the light from the object side is imaged on an image plane IMA7.

According to paragraphs [0030]400371, wherein: the first lens L71is a meniscus lens, wherein the image side surface S72is a concave surface; the second lens L72is a meniscus lens, wherein the object side surface S73is a convex surface; both of the object side surface S710and image side surface S711of the fifth lens L75are spherical surfaces; the sixth lens L76is a biconvex lens, wherein the object side surface S712is a convex surface, and both of the object side surface S712and image side surface S713are spherical surfaces; the seventh lens L77is a biconcave lens with negative refractive power and made of glass material, wherein the object side surface S714is a concave surface, the image side surface is S715is a concave surface, and both of the object side surface S714and image side surface S715are spherical surfaces; both of the object side surface S716and image side surface S717of the optical filter OF7are plane surfaces; and both of the object side surface S718and image side surface S719of the cover glass CG7are plane surfaces.

With the above design of the lenses, stop ST7, and at least one of the conditions (1)-(9) satisfied, the lens assembly7can have an effective shortened total lens length, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 19 shows the optical specification of the lens assembly7inFIG. 9.

Table 20 shows the parameters and condition values for conditions (1)-(9) in accordance with the seventh embodiment of the invention. It can be seen from Table 20 that the lens assembly7of the seventh embodiment satisfies the conditions (1)-(9).

In addition, the lens assembly7of the seventh embodiment can meet the requirements of optical performance as seen inFIGS. 10A-10C. It can be seen fromFIG. 10Athat the field curvature of tangential direction and sagittal direction in the lens assembly7of the seventh embodiment ranges from −0.03 mm to 0.04 mm. It can be seen fromFIG. 10Bthat the distortion in the lens assembly7of the seventh embodiment ranges from −12% to 0%. It can be seen fromFIG. 10Cthat the modulation transfer function of tangential direction and sagittal direction in the lens assembly7of the seventh embodiment ranges from 0.14 to 1.0. It is obvious that the field curvature and the distortion of the lens assembly7of the seventh embodiment can be corrected effectively, and the resolution of the lens assembly7of the seventh embodiment can meet the requirement. Therefore, the lens assembly7of the seventh embodiment is capable of good optical performance.

Referring toFIG. 11, the lens assembly8includes a first lens L81, a second lens L82, a third lens L83, a stop ST8, a fourth lens L84, a fifth lens L85, a sixth lens L86, a seventh lens L87, an eighth lens L88, an optical filter OF8, and a cover glass CG8, all of which are arranged in order from an object side to an image side along an optical axis OA8. In operation, the light from the object side is imaged on an image plane IMA8.

According to paragraphs [0030]-[0037], wherein: the first lens L81is a meniscus lens, wherein the image side surface S82is a concave surface; the second lens L82is a biconcave lens, wherein the object side surface S83is a concave surface; both of the object side surface S810and image side surface S811of the fifth lens L85are aspheric surfaces; the sixth lens L86is a meniscus lens, wherein the object side surface S812is a concave surface, and both of the object side surface S812and image side surface S813are spherical surfaces; the seventh lens L87is a biconcave lens with negative refractive power and made of glass material, wherein the object side surface S814is a concave surface, the image side surface is5815is a concave surface, and both of the object side surface S814and image side surface S815are spherical surfaces; the eighth lens L88is a meniscus lens with positive refractive power and made of glass material, wherein the object side surface S816is a convex surface, the image side surface is5817is a concave surface, and both of the object side surface S816and image side surface S817are aspheric surfaces; both of the object side surface S818and image side surface S819of the optical filter OF8are plane surfaces; and both of the object side surface S820and image side surface S821of the cover glass CG8are plane surfaces.

With the above design of the lenses, stop ST8, and at least one of the conditions (1)-(9) satisfied, the lens assembly8can have an effective shortened total lens length, an effective increased resolution, an effective resisted environmental temperature change, an effective corrected aberration, and an effective corrected chromatic aberration.

Table 21 shows the optical specification of the lens assembly8inFIG. 11.

The definition of aspheric surface sag z of each aspheric lens in table 21 is the same as that of in Table 1, and is not described here again.

In the eighth embodiment, the conic constant k and the aspheric coefficients A, B, C, D, E, F, G of each aspheric lens are shown in Table 22.

Table 23 shows the parameters and condition values for conditions (1)-(9) in accordance with the eighth embodiment of the invention. It can be seen from Table 23 that the lens assembly8of the eighth embodiment satisfies the conditions (1)-(9).

In addition, the lens assembly8of the eighth embodiment can meet the requirements of optical performance as seen inFIGS. 12A-12C. It can be seen fromFIG. 12Athat the field curvature of tangential direction and sagittal direction in the lens assembly8of the eighth embodiment ranges from −0.035 mm to 0.035 mm. It can be seen fromFIG. 12Bthat the distortion in the lens assembly8of the eighth embodiment ranges from −10% to 0%. It can be seen fromFIG. 12Cthat the modulation transfer function of tangential direction and sagittal direction in the lens assembly8of the eighth embodiment ranges from 0.21 to 1.0. It is obvious that the field curvature and the distortion of the lens assembly8of the eighth embodiment can be corrected effectively, and the resolution of the lens assembly8of the eighth embodiment can meet the requirement. Therefore, the lens assembly8of the eighth embodiment is capable of good optical performance.