# Patent

## Title
Imaging lens assembly

## Abstract

An imaging lens assembly is provided in the present disclosure. The imaging lens assembly includes a first lens with positive refractive power, a second lens with negative refractive power, a third lens with negative refractive power, a fourth lens with positive refractive power, and a fifth lens with negative refractive power. The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are arranged in sequence from the object side to the image side, and satisfy conditions provided in the present disclosure.

## Background
FIELD OF THE DISCLOSURE
The present disclosure relates to optical technologies, and more particular, to an imaging lens assembly applicable to a digital camera of a mobile phone or a WEB camera, which uses CCD imaging components or CMOS imaging components with high resolution.
BACKGROUND
CCD imaging components and CMOS imaging components are used widely in camera device, to meet the requirements of miniaturization and good performance of the imaging components, a wide-angle lens assembly with good optical characteristic, thin profile, and high luminous flux (namely, F number or Fno) is needed.
Japanese patent publication No. 2015-072424 discloses an imaging lens assembly including five lenses. However, as the shape of the second lens is inadequate, the optical parameters of the imaging lens assembly are as follow: Fno=2.25, 2ω≦74.6°, and TTL/IH≧1.517. In other words, the imaging lens assembly cannot meet the requirement of wide view angle, thin profile and high luminous flux.
Japanese patent publication No. 2015-060171 discloses another imaging lens assembly also including five lenses. However, as the shape of the first lens, the second lens and the third lens are inadequate ,the optical parameters of the imaging lens assembly are as follow: Fno=2.25 and 2ω≦75.6° 7. As can be seen, the imaging lens assembly also cannot meet the requirement of wide view angle, thin profile and high luminous flux.
Accordingly, an improved imaging lens assembly which can overcome the disadvantages described above is desired.



BRIEF DESCRIPTION OF THE DRAWINGS
Many aspects of the embodiment can be better understood with reference to the following drawings. The components in the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
FIG. 1 is a structural diagram of an imaging lens assembly related to an embodiment of the present disclosure;
FIG. 2 is a structural diagram of the imaging lens assembly in accordance with the first embodiment of the present disclosure;
FIG. 3 is the longitudinal aberration of the imaging lens assembly of FIG. 2;
FIG. 4 is the lateral color of the imaging lens assembly of FIG. 2;
FIG. 5 is the field curvature and distortion of the imaging lens assembly of FIG. 2;
FIG. 6 is a structural diagram of the imaging lens assembly in accordance with the second embodiment of the present disclosure;
FIG. 7 is the longitudinal aberration of the imaging lens assembly of FIG. 6;
FIG. 8 is the lateral color of the imaging lens assembly of FIG. 6;
FIG. 9 is the field curvature and distortion of the imaging lens assembly of FIG. 6.



DETAILED DESCRIPTION
The present invention will hereinafter be described in detail with reference to several embodiments.
Referring to FIG. 1, an imaging lens assembly LA according to an embodiment of the present disclosure is shown. The imaging lens assembly LA includes a lens set with five lenses, that is, a first lens L1, a second lens L2, a third lens L3, a fourth lens 4 and a fifth lens L5, which are arranged in order from the object side to the image plane. A glass filter GF is arranged between the fifth lens L5 and the image plane, the glass filter GF may be a cover glass or an IR filter. Alternatively, the glass filter GF may be arranged in other locations or even removed from the imaging lens assembly LA.
The first lens L1 has a positive refractive power, the second lens L2 has a negative refractive power, the third lens L3 also has a negative refractive power, the fourth lens L4 has a positive refractive power, and the fifth lens L5 has a negative refractive power. In practice, the five lenses L1 to L5 may be designed to have aspheric surfaces, so as to compensate aberration in the imaging lens assembly LA.
The imaging lens assembly LA as provided in the present embodiment satisfies the following conditions (1) to (3):

0.00≦|R1/R2|≦0.05   (1)

0.80≦|R3/R4|≦1.50   (2)

1.20≦|R5/R6|≦1.55   (3)

In the above conditions (1) to (3),
R1 is the curvature radius of the object side of the first lens L1;
R2 is the curvature radius of the image side of the first lens L1;
R3 is the curvature radius of the object side of the second lens L2;
R4 is the curvature radius of the image side of the second lens L2;
R5 is the curvature radius of the object side of the third lens L3; and
R6 is the curvature radius of the image side of the third lens L3.
The condition (1) defines the shape of the first lens L1. If the proportion value |R1/R2| is beyond the value range defined by condition (1), it is difficult to compensate the high order aberrations such as the spherical aberration when the imaging lens assembly LA has a less thickness and a wider view angle.
In addition, the proportion value |R1/R2| in condition (1) is preferred to be set in the value range as defined in the following condition (1-A):

0.00≦|R1/R2|0.035   (1-A)

The condition (2) defines the shape of the second lens L2. If the proportion value |R3/R4| is beyond the value range defined by condition (2), it is difficult to compensate the on-axis chromatic aberration when the imaging lens assembly LA has a less thickness and a wider view angle.
In addition, the proportion value |R3/R4| in condition (2) is preferred to be set in the value range as defined in the following condition (2-A):

0.83≦|R3/R4|≦1.20   (2-A)

The condition (3) defines the shape of the third lens L3. If the proportion value |R5/R6| is beyond the value range defined by condition (3), it is difficult to compensate off-axis chromatic aberration when the imaging lens assembly LA has a less thickness and a wider view angle.
In addition, the proportion value |R5/R6| in condition (3) is preferred to be set in the value range as defined in the following condition (3-A):

1.30≦|R5/R6|≦1.55   (3-A)

Moreover, the first lens L1 has a positive refractive power, and satisfies the following condition (4):

0.60≦f1/f≦0.80   (4)

In the above condition (4),
f is the focal length of the image lens assembly LA; and
f1 is the focal length of the first lens 1.
The condition (4) defines the positive refractive power of the first lens L1. If the proportion value f1/f is less than the minimum limit of condition (4), the positive refractive power of the first lens L1 may be too strong to compensate aberration, and the imaging lens assembly L1 is difficult to obtain a wide view angle. In contrast, when the proportion value f1/f exceeds the maximum limit of condition (4), the positive refractive power of the first lens L1 is too weak, and is adverse to the miniaturization of the imaging lens assembly LA.
The third lens L3 has a negative refractive power, and satisfies the following condition (5):

−30.00≦f3/f≦−10.00 (5)

In the above condition (5),
f is the focal length of the imaging lens assembly; and
f3 is the focal length of the third lens L3.
The condition (5) defines the negative refractive power of the third lens L3. If the proportion value f3/f is beyond the value range defined by condition (5), it is difficult to compensate the on-axis and off-axis chromatic aberration when the imaging lens assembly LA has a less thickness and a wider view angle.
Upon the condition that the five lenses L1 to L5 satisfy the aforesaid conditions, the imaging lens assembly LA is possible to have good optical characteristic as well as an ultra-thin profile and high luminous flux, and moreover, the imaging lens assembly LA may also satisfy the following parameter requirements: TTL/IH≦1.35, view angle 2ω≧78°, and Fno≦2.2.
The following description describes the imaging lens assembly LA according to the present disclosure in detail with reference to several embodiments; parameters of the imaging lens assembly LA are defined as follows, in which the unit of each of distance, radius, and central thickness is millimeter (mm):
f: the focal length of the imaging lens assembly LA;
f1: the focal length of the first lens L1;
f2: the focal length of the second lens L2;
f3: the focal length of the third lens L3;
f4: the focal length of the fourth lens L4;
f5: the focal length of the fifth lens L5;
Fno: F-number;
2ω: full view angle;
S1: the aperture stop;
R: a curvature radius of an optical surface, and may also be a central curvature radius of a lens;
R1: the curvature radius of the object side of the first lens L1;
R2: the curvature radius of the image side of the first lens L1;
R3: the curvature radius of the object side of the second lens L2;
R4: the curvature radius of the image side of the second lens L2;
R5: the curvature radius of the object side of the third lens L3;
R6: the curvature radius of the image side of the third lens L3;
R7: the curvature radius of the object side of the fourth lens L4;
R8: the curvature radius of the image side of the fourth lens L4;
R9: the curvature radius of the object side of the fifth lens L5;
R10: the curvature radius of the image side of the fifth lens L5;
R11: the curvature radius of the object side of the glass filter GF;
R12: the curvature radius of the image side of the glass filter GF;
d: an central thickness of the lens or an axial distance between lenses;
d0: the axial distance between the aperture stop S1 and the object side of the first lens L1;
d1: the central thickness of the first lens L1;
d2: the axial distance between the image side of the first lens L1 and the object side of the second lens L2;
d3: the central thickness of the second lens L2;
d4: an axial distance between the image side of the second lens L2 and the object side of the third lens L3;
d5: the central thickness of the third lens L3;
d6: the axial distance between the image side of the third lens L3 and the object side of the fourth lens L4;
d7: the central thickness of the fourth lens L4;
d8: the axial distance between the image side of the fourth lens L4 and the object side of the fifth lens L5;
d9: the central thickness of the fifth lens L5;
d10: the axial distance between the image side of the fifth lens L5 and the object side of the glass filter GF;
d11: the central thickness of the glass filter GF;
d12: the axial distance between the image side of the glass filter GF and the image plane;
nd: d line refraction index;
nd1: d line refraction index of the first lens L1;
nd2: d line refraction index of the second lens L2;
nd3: d line refraction index of the third lens L3;
nd4: d line refraction index of the fourth lens L4;
nd5: d line refraction index of the fifth lens L5;
nd6: d line refraction index of the glass filter GF;
υd: abbe number (i.e., dispersion coefficient)
υ1: abbe number of the first lens L1;
υ2: abbe number of the second lens L2;
υ3: abbe number of the third lens L3;
υ4: abbe number of the fourth lens L4;
υ5: abbe number of the fifth lens L5;
υ6: abbe number of the glass plate GF;
TTL: the total track length (i.e., an axial distance between the object side of the first lens L1 and the image plane);
LB: the axial distance between the image side of the fifth lens L5 and the image plane (including a thickness of the glass plate GF); and
IH: the image height.

y=(x2/R)/[1+{1−(k+1)(x2/R2)}1/2]+A4x4+A6x6+A8x8+A10x10+A12x12+A14x14+A16x16   (7)

In the above condition (7), R is then axial curvature radius, k is the conic coefficient, and A4, A6, A8, A10, A12, A14 and A16 are aspherical coefficients.
Optionally, aspherical surfaces of the lenses L1-L6 may be obtained according to condition (7); alternatively, the aspherical surfaces may also be obtained according to other conditions.
[Embodiment 1]
FIG. 2 illustrated an imaging lens assembly LA in accordance with the first embodiment of the present disclosure. TABLE 1 and TABLE 2 show the detailed optical data of the imaging lens assembly LA.
The optical data in TABLE 1 includes the curvature radius R, the central thickness d, the axial distance d between lenses, refraction index nd and abbe number ud of the lenses L1 to L5 in the imaging lens assembly LA. The optical data in TABLE 2 includes conic coefficient (C-coefficient) k and aspherical coefficient of the lenses L1 to L5 in the imaging lens assembly LA.












TABLE 1







R
d
nd
νd























S1
∞
d0 =
−0.200






R1
1.32067
d1 =
0.521
nd1
1.5441
ν1
56.12


R2
308.07362
d2 =
0.048


R3
−6.52179
d3 =
0.206
nd2
1.6397
ν2
23.53


R4
7.76515
d4 =
0.320


R5
13.73259
d5 =
0.217
nd3
1.6397
ν3
23.53


R6
10.48313
d6 =
0.370


R7
−4.57750
d7 =
0.587
nd4
1.5441
ν4
56.12


R8
−1.05491
d8 =
0.412


R9
−2.23086
d9 =
0.303
nd5
1.5352
ν5
56.12


R10
1.82793
d10 =
0.380


R11
∞
d11 =
0.210
nd6
1.5168
ν6
64.17


R12
∞
d12 =
0.352



















TABLE 2









C-coefficient
aspherical coefficient
















k
A4
A6
A8
A10
A12
A14
A16



















R1
0.0000E+00
−1.8652E−02
2.5012E−02
−1.2798E−01
−2.3686E−03
6.0308E−02
4.2520E−02
−3.9018E−01


R2
0.0000E+00
−4.4095E−02
−5.6359E−02
6.1137E−02
−1.9783E−01
−1.7519E−01
3.0872E−02
1.9893E−01


R3
0.0000E+00
7.9246E−02
7.0145E−02
−4.2959E−02
−8.7575E−02
−9.1949E−02
1.8885E−02
3.3327E−01


R4
7.2308E+01
1.0577E−01
3.2528E−02
5.9471E−02
1.2003E−01
−2.3360E−01
−2.4888E−01
4.4363E−01


R5
8.8934E+01
−2.6195E−01
2.3104E−02
−9.2197E−02
−5.9638E−03
2.9836E−01
2.8662E−01
−5.5527E−01


R6
3.8228E+01
−1.9252E−01
−5.4413E−02
2.4293E−02
5.9544E−02
5.5018E−02
4.8888E−02
−2.8697E−02


R7
1.1726E+01
1.4860E−02
−1.1352E−02
−3.7230E−02
4.6307E−03
3.1842E−03
1.6882E−03
2.8214E−03


R8
−9.7079E+00
−6.5434E−02
9.4545E−02
−4.2079E−02
6.7894E−09
−8.9432E−04
5.2881E−04
−1.9927E−04


R9
−3.9071E+00
−4.3364E−02
1.4049E−02
7.2638E−04
−3.2510E−04
−2.0486E−05
−6.4827E−06
2.1599E−06


R10
−1.8604E+01
−6.2066E−02
1.8411E−02
−4.7743E−03
5.8141E−04
−4.0995E−05
−6.8882E−07
8.3824E−07









The relevant optical data of the imaging lens assembly LA in the first embodiment and the values defined in the aforesaid conditions (1) to (5) are shown in TABLE 5 as provided in the subsequent paragraphs.
As can be seen in TABLE 5, the imaging lens assembly LA in the first embodiment satisfies the aforesaid conditions (1) to (5).
FIGS. 3-5 schematically illustrate the longitudinal aberration, the lateral color, the field curvature and distortion of the imaging lens assembly LA as provided in the first embodiment respectively. In FIG. 5, curve S represents the field curvature related to the sagittal plane, and curve T represents the field curvature related to the tangential plane.
As can be seen, in the first embodiment, the view angle 2ω of the imaging lens assembly LA is 80.7°, the proportion value TTL/IH of the imaging lens assembly LA is 1.338, and the F number is 2.20. In other words, the imaging lens assembly LA as provided in the first embodiment has an ultra-thin profile and a wide view angle with high luminous flux, and accordingly has good optical characteristics.
[Embodiment 2]
FIG. 6 illustrated an imaging lens assembly LA in accordance with the second embodiment of the present disclosure. TABLE 3 and TABLE 4 show the detailed optical data of the imaging lens assembly LA.
The optical data in TABLE 3 includes the curvature radius R, the central thickness d, the axial distance d between lenses, refraction index nd and abbe number ud of the lenses L1 to L5 in the imaging lens assembly LA. The optical data in TABLE 4 includes conic coefficient (C-coefficient) k and aspherical coefficient of the lenses L1 to L5 in the imaging lens assembly LA.












TABLE 3







R
d
nd
νd























S1
∞
d0 =
−0.200






R1
1.32399
d1 =
0.526
nd1
1.5441
ν1
56.12


R2
355.53042
d2 =
0.048


R3
−6.55181
d3 =
0.209
nd2
1.6397
ν2
23.53


R4
7.80198
d4 =
0.312


R5
14.89340
d5 =
0.215
nd3
1.6397
ν3
23.53


R6
9.69845
d6 =
0.381


R7
−4.68363
d7 =
0.551
nd4
1.5441
ν4
56.12


R8
−1.05516
d8 =
0.416


R9
−2.36387
d9 =
0.300
nd5
1.5352
ν5
56.12


R10
1.77356
d10 =
0.380


R11
∞
d11 =
0.210
nd6
1.5168
ν6
64.17


R12
∞
d12 =
0.376



















TABLE 4









C-coefficient
aspherical coefficient
















k
A4
A6
A8
A10
A12
A14
A16



















R1
0.0000E+00
−1.7911E−02
2.5431E−02
−1.2792E−01
−1.7725E−03
6.3301E−02
5.0670E−02
−3.7296E−01


R2
0.0000E+00
−4.4912E−02
−5.6503E−02
6.3064E−02
−1.9455E−01
−1.7115E−01
3.6001E−02
2.0336E−01


R3
0.0000E+00
7.9233E−02
8.9081E−02
−4.5298E−02
−9.0888E−02
−9.4864E−02
1.4091E−02
3.3084E−01


R4
7.0744E+01
1.0782E−01
3.1113E−02
5.8667E−02
1.1929E−01
−2.3499E−01
−2.5205E−01
4.3843E−01


R5
1.1771E+02
−2.8027E−01
2.5389E−02
−8.7283E−02
3.4021E−04
3.0528E−01
3.8505E−01
−5.4463E−01


R6
9.3813E+01
−1.9537E−01
−5.4123E−02
2.4909E−02
5.9591E−02
5.4918E−02
4.7985E−02
−2.8041E−02


R7
1.2084E+01
1.4340E−02
−1.2626E−02
−3.8186E−02
4.0802E−03
2.9598E−03
1.6856E−03
2.7792E−03


R8
−3.6624E+00
−6.4987E−02
9.4751E−02
−4.2001E−02
6.8207E−03
−8.7852E−04
5.3131E−04
−2.0015E−04


R9
−3.9477E+00
−4.3255E−02
1.4072E−02
7.3052E−04
−3.2464E−04
−2.0455E−05
−6.4815E−06
2.1743E−06


R10
−1.5889E+01
−6.1925E−02
1.8415E−02
−4.7780E−03
5.8024E−04
−4.1232E−05
−7.1163E−07
6.3085E−07









The relevant optical data of the imaging lens assembly LA in the second embodiment and the values defined in the aforesaid conditions (1) to (5) are shown in TABLE 5 as provided in the subsequent paragraphs. As can be seen in TABLE 5, the imaging lens assembly LA in the second embodiment satisfies the aforesaid conditions (1) to (5).
FIGS. 7-9 schematically illustrate the longitudinal aberration, the lateral color, the field curvature and distortion of the imaging lens assembly LA in the second embodiment respectively. In FIG. 9, curve S represents the field curvature related to the sagittal plane, and curve T represents the field curvature related to the tangential plane.
As can be seen, in the second embodiment, the view angle 2ω of the imaging lens assembly LA is 80.4°, the proportion value TTL/IH of the imaging lens assembly LA is 1.337, and the F number is 2.20. In other words, the imaging lens assembly LA as provided in the second embodiment has an ultra-thin profile and a wide view angle with high luminous flux, and accordingly has good optical characteristics.
TABLE 5 shows the values of the imaging lens assembly LA in relevant to the conditions (1) to (5) according to both the first embodiment and the second embodiment. Moreover, in TABLE 5, the unit of the value 2ω is degree(°), and the units of the values f, f1, f2, f3, f4, f5, f6, TTL, LB and IH are millimeter (mm).











TABLE 5







Embodiment 1
Embodiment 2
Formulae





















|R1/R2|
0.004
0.004
Formula (1)



|R3/R4|
0.840
0.840
Formula (2)



|R5/R6|
1.310
1.536
Formula (3)



f1/f
0.721
0.718
Formula (4)



f3/f
−21.056
−13.001
Formula (5)



Fno
2.20
2.20



2ω
80.7
80.4



TTL/IH
1.338
1.337



f
3.377
3.398



f1
2.436
2.441



f2
−5.510
−5.535



f3
−71.105
−44.176



f4
2.380
2.376



f5
−1.830
−1.847



TTL
3.926
3.924



LB
0.942
0.966



IH
2.934
2.934










In summary, the imaging lens assembly LA as provided in the present disclosure has good optical characteristic, high luminous flux as well as an ultra-thin profile, and moreover, the imaging lens assembly LA satisfies the following parameter requirements: TTL/IH≦1.35, view angle 2ω≧78°, and Fno≦2.2. Therefore, the imaging lens assembly LA is applicable to a digital camera of a mobile phone or a WEB camera, which uses CCD imaging components or CMOS imaging components with high resolution.
It is to be understood, however, that even though numerous characteristics and advantages of the present embodiment have been set forth in the foregoing description, together with details of the structures and functions of the embodiment, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

## Claims

1. An imaging lens assembly, comprising:
a first lens with positive refractive power;
a second lens with negative refractive power;
a third lens with negative refractive power;
a fourth lens with positive refractive power; and
a fifth lens with negative refractive power;
wherein the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are arranged in sequence from the object side to the image side, and satisfy following conditions (1) to (3):


0.00≦|R1/R2|≦0.05   (1)



0.80≦|R3/R4|≦1.50   (2)



1.20≦|R5/R6|≦1.55   (3)


wherein R1 is the curvature radius of the object side of the first lens, R2 is the curvature radius of the image side of the first lens; R3 is the curvature radius of the object side of the second lens, R4 is the curvature radius of the image side of the second lens; R5 is the curvature radius of the object side of the third lens, and R6 is the curvature radius of the image side of the third lens.

2. The imaging lens assembly of claim 1, further satisfying the following condition (4):


0.60≦f1/f≦0.80   (4)

wherein f is the focal length of the imaging lens assembly, and f1 is the focal length of the first lens.

3. The imaging lens assembly of claim 1, further satisfying the following condition (5):


−30.00≦f3/f≦−10.00 (5)

wherein f is the focal length of the imaging lens assembly, and f3 is the focal length of the third lens.

4. The imaging lens assembly of claim 1, wherein the first lens satisfies following conditions (1-A):


0.00≦|R1/R2|≦0.035  (1-A).

5. The imaging lens assembly of claim 1, wherein the second lens satisfies following conditions (2-A):


0.83≦|R3/R4|≦1.20  (2-A).

6. The imaging lens assembly of claim 1, wherein the third lens satisfies following conditions (3-A):


1.30≦|R5/R6|≦1.55  (3-A).