Wide-angle lens assembly

The authors of the patent

G02B9/60 - Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having five components only
G02B13/04 - Reversed telephoto objectives

The owners of the patent US9429739:

Sintai Optical (Shenzhen) Co Ltd
Asia Optical International Ltd

 

A wide-angle lens assembly includes a first lens, a second lens, a third lens, a first stop, a fourth lens, a fifth lens and a sixth lens, all of which are arranged in sequence from an object side to an image side along an optical axis. The first lens is with negative refractive power. The second lens is with negative refractive power. The third lens is with positive refractive power. The fourth lens is with positive refractive power. The fifth lens is with negative refractive power. The sixth lens is with positive refractive power. The fifth lens satisfies 16.1≦Vd5≦23.9, wherein Vd5 is an Abbe number of the fifth lens.

 

 

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a lens assembly, and more particularly to a wide-angle lens assembly.
2. Description of the Related Art
Lens assemblies for vehicles have been gradually developed toward miniaturization and wide field of view. In addition to miniaturization and wide field of view, the lens assemblies for the vehicles are required to resist the change of environment temperature and ambient light intensity due to large variations of environment temperature and ambient light intensity. However, the known wide-angle lens assembly can't satisfy such requirements. Therefore, a wide-angle lens assembly with new structure to meet the requirements of miniaturization, wide field of view, resistance to environment temperature change and resistance to ambient light intensity change is needed.
BRIEF SUMMARY OF THE INVENTION
The invention provides a wide-angle lens assembly to solve the above problems. The wide-angle lens assembly of the invention is provided with characteristics of a shortened total lens length, a larger field of view exceeding or equaling 140 degrees, resistance to environment temperature change, resistance to ambient light intensity change and still has a good optical performance.
The wide-angle lens assembly in accordance with an exemplary embodiment of the invention includes a first lens, a second lens, a third lens, a first stop, a fourth lens, a fifth lens and a sixth lens, all of which are arranged in sequence from an object side to an image side along an optical axis. The first lens is with negative refractive power. The second lens is with negative refractive power. The third lens is with positive refractive power. The fourth lens is with positive refractive power. The fifth lens is with negative refractive power. The sixth lens is with positive refractive power. The fifth lens satisfies 16.1≦Vd5≦23.9, wherein Vd5 is an Abbe number of the fifth lens.
In another exemplary embodiment, the first lens satisfies Nd1/R11≦0.185, wherein Nd1 is an index of refraction of the first lens and R11 is a radius of curvature of an object side surface of the first lens.
In yet another exemplary embodiment, the first lens is a meniscus lens and includes a convex surface facing the object side; the second lens is a meniscus lens and includes a convex surface facing the object side; and the second lens satisfies 46≦Vd2≦60, wherein Vd2 is an Abbe number of the second lens.
In another exemplary embodiment, the third lens satisfies 22.5≦Vd3≦33.6, wherein Vd3 is an Abbe number of the third lens.
In yet another exemplary embodiment, the fourth lens further includes a convex surface facing the image side.
In another exemplary embodiment, the fifth lens and the sixth lens are cemented.
In yet another exemplary embodiment, no air space exists between the fifth lens and the sixth lens.
In another exemplary embodiment, the fifth lens is a convex-concave lens and includes a convex surface facing the object side and a concave surface facing the image side; and the sixth lens is a biconvex lens.
In yet another exemplary embodiment, the wide-angle lens assembly further includes a second stop disposed between the third lens and the fourth lens wherein the third lens, the fourth lens, the first stop and the second stop satisfy 0.09≦DST/DL3L4≦0.35, wherein DST is an interval between the first stop and the second stop and DL3L4 is an interval between the third lens and the fourth lens.
In another exemplary embodiment, the wide-angle lens assembly satisfies FOV≧140 degrees, wherein FOV is a field of view of the wide-angle lens assembly.
In yet another exemplary embodiment, the wide-angle lens assembly satisfies FOV≦172 degrees, wherein FOV is a field of view of the wide-angle lens assembly.
In another exemplary embodiment, the wide-angle lens assembly satisfies FOV≧140 degrees, wherein FOV is a field of view of the wide-angle lens assembly.
In yet another exemplary embodiment, the wide-angle lens assembly further satisfies FOV≦172 degrees, wherein FOV is a field of view of the wide-angle lens assembly.
In another exemplary embodiment, the wide-angle lens assembly further satisfies FOV≧150 degrees, wherein FOV is a field of view of the wide-angle lens assembly.
In yet another exemplary embodiment, the wide-angle lens assembly further satisfies FOV≧172 degrees, wherein FOV is a field of view of the wide-angle lens assembly.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE 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 of a wide-angle lens assembly in accordance with a first embodiment of the invention;
FIG. 2A depicts a longitudinal aberration diagram of the wide-angle lens assembly in accordance with the first embodiment of the invention;
FIG. 2B is a field curvature diagram of the wide-angle lens assembly in accordance with the first embodiment of the invention;
FIG. 2C is a distortion diagram of the wide-angle lens assembly in accordance with the first embodiment of the invention;
FIGS. 2D-2F are transverse ray fan diagrams of the wide-angle lens assembly in accordance with the first embodiment of the invention;
FIG. 2G is a lateral color diagram of the wide-angle lens assembly in accordance with the first embodiment of the invention;
FIG. 3 is a lens layout of a wide-angle lens assembly in accordance with a second embodiment of the invention;
FIG. 4A depicts a longitudinal aberration diagram of the wide-angle lens assembly in accordance with the second embodiment of the invention;
FIG. 4B is a field curvature diagram of the wide-angle lens assembly in accordance with the second embodiment of the invention;
FIG. 4C is a distortion diagram of the wide-angle lens assembly in accordance with the second embodiment of the invention;
FIGS. 4D-4F are transverse ray fan diagrams of the wide-angle lens assembly in accordance with the second embodiment of the invention;
FIG. 4G is a lateral color diagram of the wide-angle lens assembly in accordance with the second embodiment of the invention;
FIG. 5 is a lens layout of a wide-angle lens assembly in accordance with a third embodiment of the invention;
FIG. 6A depicts a longitudinal aberration diagram of the wide-angle lens assembly in accordance with the third embodiment of the invention;
FIG. 6B is a field curvature diagram of the wide-angle lens assembly in accordance with the third embodiment of the invention;
FIG. 6C is a distortion diagram of the wide-angle lens assembly in accordance with the third embodiment of the invention;
FIGS. 6D-6F are transverse ray fan diagrams of the wide-angle lens assembly in accordance with the third embodiment of the invention; and
FIG. 6G is a lateral color diagram of the wide-angle lens assembly in accordance with the third embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
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.
Referring to FIG. 1, FIG. 1 is a lens layout of a wide-angle lens assembly in accordance with a first embodiment of the invention. The wide-angle lens assembly 1 includes a first lens L11, a second lens L12, a third lens L13, a first stop ST11, a second stop ST12, a fourth lens L14, a fifth lens L15, a sixth lens L16 and an Optical filter OF1, all of which are arranged in sequence from an object side to an image side along an optical axis OA1. In operation, an image of light rays from the object side is formed at an image plane IMA1. The first lens L11 is a meniscus lens and with negative refractive power, wherein the object side surface S11 is a convex surface, the image side surface S12 is a concave surface and both of the object side surface S11 and image side surface S12 are spherical surfaces. The second lens L12 is a meniscus lens and with negative refractive power, wherein the object side surface S13 is a convex surface, the image side surface S14 is a concave surface and both of the object side surface S13 and image side surface S14 are spherical surfaces. The third lens L13 is with positive refractive power, wherein the object side surface S15 is a convex surface, the image side surface S16 is a concave surface and both of the object side surface S15 and image side surface S16 are spherical surfaces. The fourth lens L14 is a concave-convex lens and with positive refractive power, wherein the object side surface S19 is a concave surface, the image side surface S110 is a convex surface, the object side surface S19 is a spherical surface and the image side surface S110 is an aspheric surface. The fifth lens L15 is a convex-concave lens and with negative refractive power, wherein the object side surface S111 is a convex surface, the image side surface S112 is a concave surface and both of the object side surface S111 and image side surface S112 are spherical surfaces. The sixth lens L16 is a biconvex lens and with positive refractive power, wherein both of the object side surface S112 and image side surface S113 are spherical surfaces. The image side surface S112 of the fifth lens L15 and the object side surface S112 of the sixth lens L16 are cemented so as to reduce chromatic aberration. Both of the object side surface S114 and image side surface S115 of the optical filter OF1 are plane surfaces.
In order to maintain excellent optical performance of the wide-angle lens assembly in accordance with the first embodiment of the invention, the wide-angle lens assembly 1 must satisfies the following five conditions:
Nd11/R111≦0.185  (1)
46≦Vd12≦60  (2)
22.5≦Vd13≦33.6  (3)
16.1≦Vd15≦23.9  (4)
0.09≦D1ST/D1L13L14≦0.35  (5)
wherein Nd11 is an index of refraction of the first lens L11, R111 is a radius of curvature of the object side surface S11 of the first lens L11, Vd12 is an Abbe number of the second lens L12, Vd13 is an Abbe number of the third lens L13, Vd15 is an Abbe number of the fifth lens L15, D1ST is an interval between the first stop ST11 and the second stop ST12 and D1L13L14 is an interval between the third lens L13 and the fourth lens L14. The wide-angle lens assembly 1 satisfying condition (4) can reduce chromatic aberration significantly.
By the above design of the lenses, stop ST11 and stop ST12, the wide-angle lens assembly 1 is provided with an increased field of view and an effective corrected aberration.
In order to achieve the above purposes and effectively enhance the optical performance, the wide-angle lens assembly 1 in accordance with the first embodiment of the invention is provided with the optical specifications shown in Table 1, which include the effective focal length, field of view, radius of curvature of each lens surface, thickness between adjacent surface, refractive index of each lens and Abbe number of each lens. Table 1 shows that the effective focal length is equal to 1.998 mm and field of view is equal to 160° for the wide-angle lens assembly 1 of the first embodiment of the invention.
TABLE 1
Effective Focal Length = 1.998 mm
Field of View = 160°
  Radius of        
Surface Curvature Thickness
Number (mm) (mm) Nd Vd Remark
S11 10.000 0.700 1.7900 52.32 The First Lens L11
S12 2.980 2.040
S13 7.254 0.600 1.7850 59.32 The Second Lens L12
S14 2.980 2.591
S15 50.993 1.400 2.0156 32.59 The Third Lens L13
S16 −7.086 0.575     Interval D167
S17 0.705     The First Stop ST11
          Interval D1ST
S18 0.800     The Second Stop ST12
          Interval D189
S19 −10.722 1.400 1.7809 61.60 The Fourth Lens L14
S110 −5.256 0.100
S111 9.258 0.600 1.85936 20.70 The Fifth Lens L15
S112 3.455 2.430 1.6100 88.67 The Sixth Lens L16
S113 −6.232 2.000
S114 0.550 1.5168 64.20 Optical Filter OF1
S115 1.616

The aspheric surface sag z of each lens in table 1 can be calculated by the following formula:
z=ch2/{1+[1−(k+1)c2h2]1/2}+Ah4+Bh6+Ch8+Dh10+Eh12+Fh14
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 and F are aspheric coefficients.
In the first embodiment, the conic constant k and the aspheric coefficients A, B, C, D, E, F of each surface are shown in Table 2.
TABLE 2
Surface              
Number k A B C D E F
S110 0 6.2559217E−04 1.4927660E−03 −9.4253857E−04 2.6951239E−04 −2.8551154E−05 5.2604729E−09

For the wide-angle lens assembly 1 of the first embodiment, the index of refraction Nd11 of the first lens L11 is equal to 1.7900, the radius of curvature R111 of the object side surface S11 of the first lens L11 is equal to 10.000 mm, the Abbe number Vd12 of the second lens L12 is equal to 59.32, the Abbe number Vd13 of the third lens L13 is equal to 32.59, the Abbe number Vd15 of the fifth lens L15 is equal to 20.70, the interval D1ST between the first stop ST11 and the second stop ST12 is equal to 0.705 mm, and the interval D1L13L14 between the third lens L13 and the fourth lens L14 is equal to 2.080 mm. According to the above data, the following values can be obtained:
Nd11/R111=0.179,
Vd12=59.32,
Vd13=32.59,
Vd15=20.70,
D1ST/D1L13L14=0.34
which respectively satisfy the above conditions (1)-(5).
By the above arrangements of the lenses, stop ST11 and stop ST12, the wide-angle lens assembly 1 of the first embodiment can meet the requirements of optical performance as seen in FIGS. 2A-2G, wherein FIG. 2A shows a longitudinal aberration diagram of the wide-angle lens assembly 1 in accordance with the first embodiment of the invention, FIG. 2B shows a field curvature diagram of the wide-angle lens assembly 1 in accordance with the first embodiment of the invention, FIG. 2C shows a distortion diagram of the wide-angle lens assembly 1 in accordance with the first embodiment of the invention, FIGS. 2D-2F show transverse ray fan diagrams of the wide-angle lens assembly 1 in accordance with the first embodiment of the invention and FIG. 2G shows a lateral color diagram of the wide-angle lens assembly 1 in accordance with the first embodiment of the invention.
It can be seen from FIG. 2A that the longitudinal aberration in the wide-angle lens assembly 1 of the first embodiment ranges between −0.06 mm and 0.00 mm for the wavelength of 0.588 μm. It can be seen from FIG. 2B that the field curvature of tangential direction and sagittal direction in the wide-angle lens assembly 1 of the first embodiment ranges between −0.15 mm and 0.00 mm for the wavelength of 0.588 μm. It can be seen from FIG. 2C that the distortion in the wide-angle lens assembly 1 of the first embodiment ranges between −90% and 0% for the wavelength of 0.588 μm. It can be seen from FIGS. 2D-2F that the transverse ray aberration in the wide-angle lens assembly 1 of the first embodiment ranges between −10.0 μm and 9.0 μm wherein the wavelength is 0.588 μm, each field is 0.0000 mm, 1.700 mm and 2.3800 mm. It can be seen from FIG. 2G that the lateral color in the wide-angle lens assembly 1 of the first embodiment ranges between −1.0 μm and 8.0 μm for the wavelength of 0.4861 μm and 0.6563 μm and field ranges between 0 mm and 3.400 mm. It is obvious that the longitudinal aberration, the field curvature, the distortion, the transverse ray aberration and the lateral color of the wide-angle lens assembly 1 of the first embodiment can be corrected effectively. Therefore, the wide-angle lens assembly 1 of the first embodiment is capable of good optical performance.
Referring to FIG. 3, FIG. 3 is a lens layout of a wide-angle lens assembly in accordance with a second embodiment of the invention. The wide-angle lens assembly 2 includes a first lens L21, a second lens L22, a third lens L23, a second stop ST22, a first stop ST21, a fourth lens L24, a fifth lens L25, a sixth lens L26 and an Optical filter OF2, all of which are arranged in sequence from an object side to an image side along an optical axis OA2. In operation, an image of light rays from the object side is formed at an image plane IMA2. The first lens L21 is a meniscus lens and with negative refractive power, wherein the object side surface S21 is a convex surface, the image side surface S22 is a concave surface and both of the object side surface S21 and image side surface S22 are spherical surfaces. The second lens L22 is a meniscus lens and with negative refractive power, wherein the object side surface S23 is a convex surface, the image side surface S24 is a concave surface, the object side surface S23 is a spherical surface and the image side surface S24 is an aspheric surfaces. The third lens L23 is a biconvex lens and with positive refractive power, wherein the object side surface S25 is an aspheric surface and the image side surface S26 is a spherical surface. The fourth lens L24 is a biconvex lens and with positive refractive power, wherein the object side surface S29 is an aspheric surface and the image side surface S210 is a spherical surface. The fifth lens L25 is a convex-concave lens and with negative refractive power, wherein the object side surface S211 is a convex surface, the image side surface S212 is a concave surface and both of the object side surface S211 and image side surface S212 are spherical surfaces. The sixth lens L26 is a biconvex lens and with positive refractive power, wherein both of the object side surface S212 and image side surface S213 are spherical surfaces. The image side surface S212 of the fifth lens L25 and the object side surface S212 of the sixth lens L26 are cemented so as to reduce chromatic aberration. Both of the object side surface S214 and image side surface S215 of the optical filter OF2 are plane surfaces.
In order to maintain excellent optical performance of the wide-angle lens assembly in accordance with the second embodiment of the invention, the wide-angle lens assembly 2 must satisfies the following five conditions:
Nd21R211≦0.185  (6)
46≦Vd22≦60  (7)
22.5≦Vd23≦33.6  (8)
16.1≦Vd25≦23.9  (9)
0.09≦D2ST/D2L23L24≦0.35  (10)
wherein Nd21 is an index of refraction of the first lens L21, R211 is a radius of curvature of the object side surface S21 of the first lens L21, Vd22 is an Abbe number of the second lens L22, Vd23 is an Abbe number of the third lens L23, Vd25 is an Abbe number of the fifth lens L25, D2ST is an interval between the second stop ST22 and the first stop ST21 and D2L23L24 is an interval between the third lens L23 and the fourth lens L24. The wide-angle lens assembly 2 satisfying condition (9) can reduce chromatic aberration significantly.
By the above design of the lenses, stop ST21 and stop ST22, the wide-angle lens assembly 2 is provided with an increased field of view and an effective corrected aberration.
In order to achieve the above purposes and effectively enhance the optical performance, the wide-angle lens assembly 2 in accordance with the second embodiment of the invention is provided with the optical specifications shown in Table 3, which include the effective focal length, field of view, radius of curvature of each lens surface, thickness between adjacent surface, refractive index of each lens and Abbe number of each lens. Table 3 shows that the effective focal length is equal to 2.036 mm and field of view is equal to 165° for the wide-angle lens assembly 2 of the second embodiment of the invention.
TABLE 3
Effective Focal Length = 2.036 mm
Field of View = 165°
  Radius of        
Surface Curvature Thickness
Number (mm) (mm) Nd Vd Remark
S21 16.339 2.200 1.7725 51.60 The First Lens L21
S22 3.200 3.191
S23 74.576 0.800 1.5350 54.71 The Second Lens L22
S24 2.597 1.160
S25 9.622 2.000 1.6142 29.58 The Third Lens L23
S26 −6.159 1.489     Interval D267
S27 1.100     The Second Stop ST22
          Interval D2ST
S28 1.090     The first Stop ST21
          Interval D289
S29 41.090 1.345 1.5913 63.14 The Fourth Lens L24
S210 −4.320 0.100
S211 9.710 0.550 1.9429 17.90 The Fifth Lens L25
S212 4.583 3.760 1.4388 90.95 The Sixth Lens L26
S213 −5.664 2.100
S214 0.800 1.5168 64.20 Optical Filter OF2
S215 1.285

The aspheric surface sag z of each lens in table 3 can be calculated by the following formula:
z=ch2/{1+[1−(k+1)c2h2]1/2}+Ah4+Bh6+Ch8+Dh10
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 second embodiment, the conic constant k and the aspheric coefficients A, B, C, D of each surface are shown in Table 4.
TABLE 4
Surface          
Number k A B C D
 
S24 −0.482909622 −2.6057500E−03 −7.4802228E−04 1.7268449E−05 −4.4051336E−06
S25 0 −2.6760090E−04 −4.1678164E−04 7.1327382E−05 −4.8110500E−06
S29 0 −5.0776120E−03  1.2955517E−03 −4.4681899E−04   5.8194312E−05

For the wide-angle lens assembly 2 of the second embodiment, the index of refraction Nd21 of the first lens L21 is equal to 1.7725, the radius of curvature R211 of the object side surface S21 of the first lens L21 is equal to 16.339 mm, the Abbe number Vd22 of the second lens L22 is equal to 54.71, the Abbe number Vd23 of the third lens L23 is equal to 29.58, the Abbe number Vd25 of the fifth lens L25 is equal to 17.90, the interval D2ST between the second stop ST22 and the first stop ST21 is equal to 1.100 mm, and the interval D2L23L24 between the third lens L23 and the fourth lens L24 is equal to 3.679 mm. According to the above data, the following values can be obtained:
Nd21/R211=0.108,
Vd22=54.71,
Vd23=29.58,
Vd25=17.90,
D2ST/D2L23L24=0.30
which respectively satisfy the above conditions (6)-(10).
By the above arrangements of the lenses, stop ST21 and stop ST22, the wide-angle lens assembly 2 of the second embodiment can meet the requirements of optical performance as seen in FIGS. 4A-4G, wherein FIG. 4A shows a longitudinal aberration diagram of the wide-angle lens assembly 2 in accordance with the second embodiment of the invention, FIG. 4B shows a field curvature diagram of the wide-angle lens assembly 2 in accordance with the second embodiment of the invention, FIG. 4C shows a distortion diagram of the wide-angle lens assembly 2 in accordance with the second embodiment of the invention, FIGS. 4D-4F show transverse ray fan diagrams of the wide-angle lens assembly 2 in accordance with the second embodiment of the invention and FIG. 4G shows a lateral color diagram of the wide-angle lens assembly 2 in accordance with the second embodiment of the invention.
It can be seen from FIG. 4A that the longitudinal aberration in the wide-angle lens assembly 2 of the second embodiment ranges between 0 mm and 0.03 mm for the wavelength of 0.588 μm. It can be seen from FIG. 4B that the field curvature of tangential direction and sagittal direction in the wide-angle lens assembly 2 of the second embodiment ranges between −0.05 mm and 0.04 mm for the wavelength of 0.588 μm. It can be seen from FIG. 4C that the distortion in the wide-angle lens assembly 2 of the second embodiment ranges between −85% and 0% for the wavelength of 0.588 μm. It can be seen from FIGS. 4D-4F that the transverse ray aberration in the wide-angle lens assembly 2 of the second embodiment ranges between −4.6 μm and 8.0 μm wherein the wavelength is 0.588 μm, each field is 0.0000 mm, 1.700 mm and 2.3800 mm. It can be seen from FIG. 4G that the lateral color in the wide-angle lens assembly 2 of the second embodiment ranges between −0.5 μm and 4.0 μm for the wavelength of 0.4861 μm and 0.6563 μm and field ranges between 0 mm and 3.400 mm. It is obvious that the longitudinal aberration, the field curvature, the distortion, the transverse ray aberration and the lateral color of the wide-angle lens assembly 2 of the second embodiment can be corrected effectively. Therefore, the wide-angle lens assembly 2 of the second embodiment is capable of good optical performance.
Referring to FIG. 5, FIG. 5 is a lens layout of a wide-angle lens assembly in accordance with a third embodiment of the invention. The wide-angle lens assembly 3 includes a first lens L31, a second lens L32, a third lens L33, a first stop ST31, a second stop ST32, a fourth lens L34, a fifth lens L35, a sixth lens L36 and an Optical filter OF3, all of which are arranged in sequence from an object side to an image side along an optical axis OA3. In operation, an image of light rays from the object side is formed at an image plane IMA3. The first lens L31 is a meniscus lens and with negative refractive power, wherein the object side surface S31 is a convex surface, the image side surface S32 is a concave surface and both of the object side surface S31 and image side surface S32 are spherical surfaces. The second lens L32 is a meniscus lens and with negative refractive power, wherein the object side surface S33 is a convex surface, the image side surface S34 is a concave surface and both of the object side surface S33 and image side surface S34 are spherical surfaces. The third lens L33 is with positive refractive power, wherein the object side surface S35 is a concave surface, the image side surface S36 is a convex surface and both of the object side surface S35 and image side surface S36 are spherical surfaces. The fourth lens L34 is a biconvex lens and with positive refractive power, wherein both of the object side surface S39 and image side surface S310 are spherical surfaces. The fifth lens L35 is a convex-concave lens and with negative refractive power, wherein the object side surface S311 is a convex surface, the image side surface S312 is a concave surface and both of the object side surface S311 and image side surface S312 are spherical surfaces. The sixth lens L36 is a biconvex lens and with positive refractive power, wherein both of the object side surface S312 and image side surface S313 are spherical surfaces. The image side surface S312 of the fifth lens L35 and the object side surface S312 of the sixth lens L36 are cemented so as to reduce chromatic aberration. Both of the object side surface S314 and image side surface S315 of the optical filter OF3 are plane surfaces.
In order to maintain excellent optical performance of the wide-angle lens assembly in accordance with the third embodiment of the invention, the wide-angle lens assembly 3 must satisfies the following five conditions:
Nd31/R311≦0.185  (11)
46≦Vd32≦60  (12)
22.5≦Vd33≦33.6  (13)
16.1≦Vd35≦23.9  (14)
0.09≦D3ST/D3L33L34≦0.35  (15)
wherein Nd31 is an index of refraction of the first lens L31, R311 is a radius of curvature of the object side surface S31 of the first lens L31, Vd32 is an Abbe number of the second lens L32, Vd33 is an Abbe number of the third lens L33, Vd35 is an Abbe number of the fifth lens L35, D3ST is an interval between the first stop ST31 and the second stop ST32 and D3L33L34 is an interval between the third lens L33 and the fourth lens L34. The wide-angle lens assembly 3 satisfying condition (14) can reduce chromatic aberration significantly.
By the above design of the lenses, stop ST31 and stop ST32, the wide-angle lens assembly 3 is provided with an increased field of view and an effective corrected aberration.
In order to achieve the above purposes and effectively enhance the optical performance, the wide-angle lens assembly 3 in accordance with the third embodiment of the invention is provided with the optical specifications shown in Table 5, which include the effective focal length, field of view, radius of curvature of each lens surface, thickness between adjacent surface, refractive index of each lens and Abbe number of each lens. Table 5 shows that the effective focal length is equal to 2.4025 mm and field of view is equal to 150° for the wide-angle lens assembly 3 of the third embodiment of the invention.
TABLE 5
Effective Focal Length = 2.4025 mm
Field of View = 150°
  Radius of        
Surface Curvature Thickness
Number (mm) (mm) Nd Vd Remark
S31 10.000 0.7 1.7900 54.32 The First Lens L31
S32 2.980 2.04
S33 5.336 0.6 2.0500 46.00 The Second Lens L32
S34 2.980 3.477516
S35 −14.021 1.4 1.8366 25.20 The Third Lens L33
S36 −5.154 0.18765     Interval D367
S37 0.4     The First Stop ST31
          Interval D3ST
S38 2.996662     The Second Stop ST32
          Interval D389
S39 871.324 1.4 1.6088 70.84 The Fourth Lens L34
S310 −7.966 0.1
S311 12.661 0.6 1.9467 22.32 The Fifth Lens L35
S312 4.069 4.3 1.7696 65.29 The Sixth Lens L36
S313 −16.770 4
S314 0.75 1.5168 64.20 Optical Filter OF3
S315 0.99

For the wide-angle lens assembly 3 of the third embodiment, the index of refraction Nd31 of the first lens L31 is equal to 1.7900, the radius of curvature R311 of the object side surface S31 of the first lens L31 is equal to 10.000 mm, the Abbe number Vd32 of the second lens L32 is equal to 46.00, the Abbe number Vd33 of the third lens L33 is equal to 25.20, the Abbe number Vd35 of the fifth lens L35 is equal to 22.32, the interval D3ST between the first stop ST31 and the second stop ST32 is equal to 0.400 mm, and the interval D3L33L34 between the third lens L33 and the fourth lens L34 is equal to 3.584 mm. According to the above data, the following values can be obtained:
Nd31/R311=0.179,
Vd32=46.00,
Vd33=25.20,
Vd35=22.32,
D3ST/D3L33L34=0.11
which respectively satisfy the above conditions (11)-(15).
By the above arrangements of the lenses, stop ST31 and stop ST32, the wide-angle lens assembly 3 of the third embodiment can meet the requirements of optical performance as seen in FIGS. 6A-6G, wherein FIG. 6A shows a longitudinal aberration diagram of the wide-angle lens assembly 3 in accordance with the third embodiment of the invention, FIG. 6B shows a field curvature diagram of the wide-angle lens assembly 3 in accordance with the third embodiment of the invention, FIG. 6C shows a distortion diagram of the wide-angle lens assembly 3 in accordance with the third embodiment of the invention, FIGS. 6D-6F show transverse ray fan diagrams of the wide-angle lens assembly 3 in accordance with the third embodiment of the invention and FIG. 6G shows a lateral color diagram of the wide-angle lens assembly 3 in accordance with the third embodiment of the invention.
It can be seen from FIG. 6A that the longitudinal aberration in the wide-angle lens assembly 3 of the third embodiment ranges between −0.08 mm and 0.00 mm for the wavelength of 0.588 μm. It can be seen from FIG. 6B that the field curvature of tangential direction and sagittal direction in the wide-angle lens assembly 3 of the third embodiment ranges between −0.15 mm and 0.015 mm for the wavelength of 0.588 μm. It can be seen from FIG. 6C that the distortion in the wide-angle lens assembly 3 of the third embodiment ranges between −65% and 0% for the wavelength of 0.588 μm. It can be seen from FIGS. 6D-6F that the transverse ray aberration in the wide-angle lens assembly 3 of the third embodiment ranges between −24.0 μm and 8.0 μm wherein the wavelength is 0.588 μm, each field is 0.0000 mm, 1.7000 mm and 2.3800 mm. It can be seen from FIG. 6G that the lateral color in the wide-angle lens assembly 3 of the third embodiment ranges between −1.5 μm and 7.5 μm for the wavelength of 0.4861 μm and 0.6563 μm and field ranges between 0 mm and 3.1000 mm. It is obvious that the longitudinal aberration, the field curvature, the distortion, the transverse ray aberration and the lateral color of the wide-angle lens assembly 3 of the third embodiment can be corrected effectively. Therefore, the wide-angle lens assembly 3 of the third embodiment is capable of good optical performance.
In the above embodiment, the fifth lens and the sixth lens are cemented to form a cemented lens. However, it has the same effect and falls into the scope of the invention that there is no air space between the fifth lens and the sixth lens.


1. A wide-angle lens assembly comprising a first lens, a second lens, a third lens, a first stop, a second stop, a fourth lens, a fifth lens and a sixth lens, all of which are arranged in sequence from an object side to an image side along an optical axis, wherein:
the first lens is with negative refractive power;
the second lens is with negative refractive power;
the third lens is with positive refractive power;
the fourth lens is with positive refractive power;
the fifth lens is with negative refractive power;
the sixth lens is with positive refractive power;
the fifth lens satisfies:

16.1≦Vd 5≦23.9
wherein Vd5 is an Abbe number of the fifth lens;
the second stop is disposed between the third lens and the fourth lens; and
the third lens, the fourth lens, the first stop and the second stop satisfy:

0.09≦D ST /D L3L4≦0.35
wherein DST is an interval between the first stop and the second stop and DL3L4 is an interval between the third lens and the fourth lens.
2. The wide-angle lens assembly as claimed in claim 1, wherein the first lens satisfies:

Nd 1 /R 11≦0.185
wherein Nd1 is an index of refraction of the first lens and R11 is a radius of curvature of an object side surface of the first lens.
3. The wide-angle lens assembly as claimed in claim 1, wherein:
the first lens is a meniscus lens and comprises a convex surface facing the object side;
the second lens is a meniscus lens and comprises a convex surface facing the object side; and
the second lens satisfies:

46≦Vd 2≦60
wherein Vd2 is an Abbe number of the second lens.
4. The wide-angle lens assembly as claimed in claim 1, wherein the third lens satisfies:

22.5≦Vd 3≦33.6
wherein Vd3 is an Abbe number of the third lens.
5. The wide-angle lens assembly as claimed in claim 1, wherein the fourth lens further comprises a convex surface facing the image side.
6. The wide-angle lens assembly as claimed in claim 1, wherein the fifth lens and the sixth lens are cemented.
7. The wide-angle lens assembly as claimed in claim 1, wherein no air space exists between the fifth lens and the sixth lens.
8. The wide-angle lens assembly as claimed in claim 1, wherein:
the fifth lens is a convex-concave lens and comprises a convex surface facing the object side and a concave surface facing the image side; and
the sixth lens is a biconvex lens.
9. The wide-angle lens assembly as claimed in claim 1, wherein the wide-angle lens assembly satisfies:

FOV≦172 degrees,
wherein FOV is a field of view of the wide-angle lens assembly.
10. The wide-angle lens assembly as claimed in claim 1, wherein the wide-angle lens assembly satisfies:

FOV≦140 degrees,
wherein FOV is a field of view of the wide-angle lens assembly.
11. The wide-angle lens assembly as claimed in claim 10, wherein the wide-angle lens assembly further satisfies:

FOV≦172 degrees,
wherein FOV is a field of view of the wide-angle lens assembly.
12. The wide-angle lens assembly as claimed in claim 10, wherein the wide-angle lens assembly further satisfies:

FOV≧150 degrees,
wherein FOV is a field of view of the wide-angle lens assembly.
13. The wide-angle lens assembly as claimed in claim 12, wherein the wide-angle lens assembly further satisfies:

FOV≦172 degrees,
wherein FOV is a field of view of the wide-angle lens assembly.

 

 

Patent trol of patentswamp
Similar patents
an optical lens system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element. the first lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof. the second lens element has negative refractive power. the third lens element with positive refractive power has an image-side surface being convex in a paraxial region thereof, wherein both of the surfaces thereof are aspheric. the fourth lens element with negative refractive power has an image-side surface being concave in a paraxial region thereof, wherein the image-side surface of the fourth lens element has at least one convex shape in an off-axis region thereof, and both of the surfaces thereof are aspheric. the optical lens system has a total of four lens elements with refractive power.
a projection zoom lens in which a magnification change operation is performed by moving three to four lens groups as moving groups, wherein a first lens group, which is a lens group on the most-magnification side, substantially consists of a moving group having a negative refractive power; a lens group on the most-reduction side is composed of a moving group having a positive refractive power; and the first lens group which is the lens group the most-magnification side substantially consists of two lenses. in this case, conditional formula below is satisfied, where fw is the focal length of the entire system at the wide angle end and fm is the focal length of the lens group on the most-magnification side:
−3.5<fm/fw<−1.0  .
this achieves miniaturization and cost reduction, and corrects various aberrations satisfactorily.
a retrofocus-type wide-angle lens consists of a negative first lens-group, a positive second lens-group, and a positive third lens-group in this order from an object-side. the first lens-group consists of a positive meniscus-lens with its convex surface facing the object-side and three negative meniscus-lenses with their convex surfaces facing the object-side in this order from the object-side. the second lens-group includes two cemented lenses, and a lens closest to an image-side in the second lens-group is one of the at least two cemented lenses. the third lens-group consists of a 3a-th lens-group, which consists of a positive meniscus-lens with its convex surface facing the object-side and a negative meniscus-lens with its convex surface facing the object-side, and a 3b-th lens-group, which includes at least two cemented lenses and has positive refractive power as a whole, in this order from the object-side.
an optical imaging lens includes: a first, second, third and fourth lens element, the first lens element having an object-side surface with a convex portion in a vicinity of the optical axis, the second lens element having an object-side surface with a convex portion in a vicinity of the optical axis, and an image-side surface with a concave portion in a vicinity of its periphery, the third lens element having an image-side surface with a convex portion in a vicinity of the optical axis, the fourth lens element having an image-side surface with a concave portion in a vicinity of the optical axis, wherein the optical imaging lens set does not include any lens element with refractive power other than said first, second, third and fourth lens elements.
an image-acquisition device is consists of a single objective optical system; an image-acquisition element that acquires an image of an optical image of an object formed by the objective optical system; an optical component that can be inserted into and removed from the optical axis of the objective optical system, at an intermediate position on the optical axis; and a moving mechanism that moves the optical component between a position on the optical axis of the objective optical system and a position off the optical axis. the optical component has a deflecting surface for deflecting the optical axis of the objective optical system and a refracting surface having power.
the imaging lens consists essentially of a negative first lens having a meniscus shape with a convex surface toward the object side; a negative second lens, a positive third lens; and a positive lens. when the focal length of the entire system is f, a half angle of view is ω, and the distance from the object-side surface of the first lens to the imaging plane along the optical axis is l, conditional formula below is satisfied:
0.78<2*f*tan/l+0.005*ω<1.00  .
an optical system includes, in order from object side: a positive first lens unit; and a positive second lens unit moving during focusing. the second lens unit includes, in order from object side, a front unit, an aperture stop, and a positive rear unit. the first unit includes a negative lens that has a convex surface facing object side and is arranged closest to object side, and three or more positive lenses on image side of the negative lens. a distance, on optical axis, from a lens surface on object side of a second positive lens counted from image side of the three or more positive lenses to a lens surface closest to image side of the first unit, and a distance, on optical axis, between a lens surface closest to object side and that closest to image side of the first unit are each appropriately set.
Imaging lens // US9417431
a compact, wide view-field imaging lens with a small f-value which corrects aberrations properly. its elements are arranged in order from an object side to an image side: an aperture stop, positive first lens having convex surfaces on the object and image sides, negative second lens having a concave object-side surface near an optical axis, positive meniscus third lens having a convex image-side surface, and negative meniscus double-sided aspheric fourth lens having a concave image-side surface near the optical axis. its f-value is smaller than 2.4 and it satisfies conditional expressions to below:
0.15<f12/f34<0.5  
0.1<|r1/r2|<0.5  
1.0<f1/f3<1.6  
    • where
    • f1: first lens focal length
    • f3: third lens focal length
    • f12: composite focal length of the first and second lenses
    • f34: composite focal length of the third and fourth lenses
    • r1: curvature radius of the first lens object-side surface
    • r2: curvature radius of the first lens image-side surface.
a dual-aperture zoom camera comprising a wide camera with a respective wide lens and a tele camera with a respective tele lens, the wide and tele cameras mounted directly on a single printed circuit board, wherein the wide and tele lenses have respective effective focal lengths eflw and eflt and respective total track lengths ttlw and ttlt and wherein ttlw/eflw>1.1 and ttlt/eflt<1.0. optionally, the dual-aperture zoom camera may further comprise an optical ois controller configured to provide a compensation lens movement according to a user-defined zoom factor and a camera tilt through lmv=ct*eflzf, where eflzf is a zoom-factor dependent effective focal length.
systems and methods for inspection are provided utilizing a wide angle optical system. the optical system includes a wide angle input lens group and an output lens group. the wide angle input lens group is configured to receive wide-angle radiation, e.g., having an angular spread of 60 degrees or more, from an object surface, and produce imageable radiation. the wide angle input lens group is arranged such that no intermediate focused image is formed within or after the wide angle input lens group. the output lens group is configured to receive the imageable radiation from the wide angle input lens group and focus the imageable radiation onto an image plane to image at least part of the object surface. a detector receives the image of the at least part of the object surface and, based on the received image, detects, for example, contamination on the object surface.
To top