# Patent

## Title
Camera lens

## Abstract

A camera lens is disclosed. The camera lens includes six piece ultra-thin and wide angle lenses with excellent optical properties and with chromatic aberration sufficiently corrected as follows: a first lens with positive refractive power; a second lens with negative refractive power; a third lens with positive refractive power; a fourth lens with negative refractive power; a fifth lens with positive refractive power; and a sixth lens with negative refractive power which are arranged sequentially from object side. The camera lens is characterized in that it meets specified conditions.

## Background
FIELD OF THE INVENTION
The present invention relates to a camera lens, and more particularly to a camera lens very suitable for mobile phone camera module and WEB camera lens etc. equipped with high-pixel camera elements such as CCD, CMOS etc.
DESCRIPTION OF RELATED ART
In recent years, various camera devices equipped with camera elements such as CCD, CMOS are extensively popular. Along with development on camera lens toward miniaturization and high performance, ultra-thin and high-luminous flux (Fno) wide angle camera lenses with excellent optical properties are needed.
The technology related to the camera lens comprises six pieces ultra-thin and high-luminous flux (Fno) wide angle lenses with excellent optical properties. The camera lens mentioned in the proposal is composed of six piece lenses which are arranged sequentially from an object side to an image side: a first lens with positive refractive power; a second lens with negative refractive power; a third lens with positive refractive power; a fourth lens with negative refractive power and a fifth lens with positive refractive power; a sixth lens with negative refractive power.
The camera lens disclosed in embodiments 4, 7 of the Prior Reference Document 1 is composed of above mentioned six piece lenses, but the shape of the first lens and the third lens is improper and refractive power distribution of the second lens is insufficient, therefore Fno 2.19 and 2.14 brightness is not sufficient.
The camera lens disclosed in embodiment 3 of the Prior Reference Document 2 is composed of above mentioned six piece lenses, Fno=1.85 high-luminous flux, but the shape of the first lens and the third lens is improper and refractive power distribution of the second lens is insufficient; so it is not sufficiently ultra-thin.
PRIOR REFERENCE DOCUMENTS
[Prior Reference Document 1] Japan Patent Publication No. JP2015-194528.
[Prior Reference Document 2] Japan Patent Publication No. JP2015-079175.
Therefore, it is necessary to provide a novel camera lens to solve the above-mentioned technical problem.



BRIEF DESCRIPTION OF THE DRAWINGS
Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings 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 an illustrative structure of a camera lens LA of the present disclosure.
FIG. 2 is an illustrative structure of a camera lens LA in accordance with a first embodiment (Embodiment 1) of the present disclosure.
FIG. 3 is a Longitudinal Aberration diagram of the camera lens LA in the Embodiment 1.
FIG. 4 is a Lateral Color Aberration diagram of the camera lens LA in the Embodiment 1.
FIG. 5 is a Field Curvature Distortion of the camera lens LA in the Embodiment 1.
FIG. 6 is an illustrative structure of a camera lens LA in accordance with a second embodiment (Embodiment 2) of the present disclosure.
FIG. 7 is a Longitudinal Aberration diagram of the camera lens LA in the Embodiment 2.
FIG. 8 is the Lateral Color Aberration diagram of the camera lens LA in the Embodiment 2.
FIG. 9 is a Field Curvature Distortion of the camera lens LA in the Embodiment 2.



DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
The present invention will hereinafter be described in detail with reference to exemplary embodiments. To make the technical problems to be solved, technical solutions and beneficial effects of present disclosure more apparent, the present disclosure is described in further detail together with the figures and the embodiments. It should be understood the specific embodiments described hereby is only to explain this disclosure, not intended to limit this disclosure.
A camera lens LA in accordance with an embodiment of the present disclosure includes, in an order from an object side to an image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5 and a sixth lens L6. A glass plate GF is arranged between the sixth lens L6 and the imaging surface. And a glass cover or an optical filter having the function of filtering IR can serve as the glass plate GF.o Moreover, it shall be OK if no glass plate GF is arranged between the sixth lens L6 and the imaging surface.
The first lens has positive refractive power; the second lens has negative refractive power; the third lens has positive refractive power; the fourth lens has negative refractive power; the fifth lens has positive refractive power; and the sixth lens has negative refractive power. Moreover, the surfaces of the six lenses should be designed as the aspheric shape preferably in order to correct the aberration well.
The camera lens LA satisfies the following conditions (1) ̃(4):

−5.00≦f2/f≦−1.60  (1);

1.80≦f3/f≦5.00  (2);

−1.80≦(R1+R2)/(R1−R2)≦−1.30  (3);

0.70≦(R5+R6)/(R5−R6)≦1.50  (4); where,

f: overall focal distance of the camera lens;

f2: focal distance of the second lens L2;

f3: focal distance of the third lens L3;

R1: the curvature radius of the first lens L1's object side surface;

R2: the curvature radius of the first lens L1's image side surface;

R5: the curvature radius of the third lens L3's object side surface;

R6: the curvature radius of the third lens L3's image side surface.

The negative refractive power of the second lens L2 is specified in the condition (1). Correction of chromatic aberration on axle and outside of axle becomes difficult when numerical values exceed the range of condition (1).
Therefore, numerical range of condition (1) should be set within the numerical range of the following condition (1-A) preferably,

−3.00≦f2/f≦−1.80  (1-A)

The positive refractive power of the third lens L3 is specified in the condition (2). Moreover, the development of ultra-thin and wide angle trend of Fno≦2.0 cannot be implemented easily outside the range of the condition (2).
Therefore, numerical range of condition (2) should be set within the numerical range of the following condition (2-A) preferably,

2.30≦f3/f≦3.90  (2-A)

The shape of the first lens L1 is specified in the condition (3). Moreover, the development of ultra-thin and wide angle trend of Fno≦2.0 cannot be implemented easily outside the range of the condition (3).
Therefore, numerical range of condition (3) should be set within the numerical range of the following condition (3-A) preferably,

−1.65≦(R1+R2)/(R1−R2)≦−1.40  (3-A)

The shape of the third lens L3 is specified in the condition (4). Moreover, the development of ultra-thin and wide angle trend of Fno≦2.0 cannot be implemented easily outside the range of the Condition (4).
Therefore, numerical range of condition (4) should be set within the numerical range of the following condition (4-A) preferably,

0.75≦R5/R6≦1.25  (4-A)

The second lens L2 has negative refractive power and meets following condition (5).

1.80≦(R3+R4)/(R3−R4)≦4.00  (5); where,

R3: curvature radius of the second lens L2's object side surface;

R4: curvature radius of the second lens L2's image side surface.

Shape of the second lens L2 is specified in the condition (5). Correction of chromatic aberration on axle and outside of axle becomes difficult when numerical values exceed the range of condition (5).
Therefore, numerical range of condition (5) should be set within the numerical range of the following condition (5-A) preferably,

2.00≦(R3+R4)/(R3−R4)≦3.70  (5-A)

The third lens L3 has positive refractive power and meets following condition (6).

0.07≦d5/f≦0.12  (6); where,

f: overall focal distance of the camera lens;

d5: center thickness of the third lens L3.

Ratio of center thickness of the third lens L3 to the overall focal distance of the camera lens is specified in condition (6). Moreover, the development of ultra-thin and wide angle trend of Fno≦2.0 cannot be implemented easily outside the range of the condition (6).
Because 6 lenses of camera Lens all have the stated formation and meet all the conditions, so it is possible to produce a camera lens which is composed of 6 lenses with excellent optional properties, TTL(optical length)/IH(image height)≦1.45, ultrathin, wide angle 2ω≧76°, Fno≦2.0
The camera lens LA of the invention shall be explained below by using the embodiments. Moreover, the symbols used in all embodiments are shown as follows. And mm shall be taken as the units of the distance, the radius and the center thickness.
f: overall focal distance of the camera lens LA
f1: focal distance of the first lens L1
f2: focal distance of the second lens L2
f3: focal distance of the third lens L3
f4: focal distance of the fourth lens L4
f5: focal distance of the fifth lens L5
f6: focal distance of the sixth lens L6
Fno: F value
2ω: total angle of view
S1: aperture
R: curvature radius of optical surface, central curvature radius when the lens is involved
R1: curvature radius of the first lens L1's object side surface
R2: curvature radius of the first lens L1's image side surface
R3: curvature radius of the second lens L2's object side surface
R4: curvature radius of the second lens L2's image side surface
R5: curvature radius of the third lens L3's object side surface
R6: curvature radius of the third lens L3's image side surface
R7: curvature radius of the fourth lens L4's object side surface
R8: curvature radius of the fourth lens L4's image side surface
R9: curvature radius of the fifth lens L5's object side surface
R10: curvature radius of the fifth lens L5's image side surface
R11: curvature radius of the sixth lens L6's object side surface
R12: curvature radius of the sixth lens L6's image side surface
R13: curvature radius of the glass plate GF's object side surface
R14: curvature radius of the glass plate GF's image side surface
d: center thickness of lenses or the distance between lenses
d0: distance from the open aperture S1 to the object side of the first lens L1
d1: center thickness of the first lens L1
d2: distance from the image side surface of the first lens L1 to the object side surface of the second lens L2
d3: center thickness of the second lens L2
d4: axial distance from the image side surface of the second lens L2 to the object side surface of the third lens L3
d5: center thickness of the third lens L3
d6: axial distance from the image side surface of the third lens L3 to the object side surface of the fourth lens L4
d7: center thickness of the fourth lens L4
d8: axial distance from the image side surface of the fourth lens L4 to the object side surface of the fifth lens L5
d9: center thickness of the fifth lens L5
d10: axial distance from the image side surface of the fifth lens L5 to the object side surface of the sixth lens L6
d11: center thickness of the sixth lens L6
d12: axial distance from the image side surface of the sixth lens L6 to the object side surface of the glass plate GF
d13: center thickness of the glass plate GF
d14: axial distance from the image side surface to the imaging surface of the glass plate GF
nd: refractive power of line d
nd1: refractive power of line d of the first lens L1
nd2: refractive power of line d of the second lens L2
nd3: refractive power of line d of the third lens L3
nd4: refractive power of line d of the fourth lens L4
nd5: refractive power of line d of the fifth lens L5
nd6: refractive power of line d of the sixth lens L6
nd7: refractive power of line d of the glass plate GF
vd: abbe number
v1: abbe number of the first lens L1
v2: abbe number of the second lens L2
v3: abbe number of the third lens L3
v4: abbe number of the fourth lens L4
v5: abbe number of the fifth lens L5
v6: abbe number of the sixth lens L6
v7: abbe number of the glass plate GF
TTL: optical length (axial distance from object side surface to the imaging surface of the first lens L1)
LB: axial distance (including the thickness of the glass plate GF) from the image side surface to the imaging surface of the sixth lens L6;
IH: image height

y=(x2/R)/[1+{1−(k+1)(x2/R2)}1⁄2]+A4x4+A6x6+A8x8+A10x10+A12x12+A14 x14+A16x16  (7);

where R indicates the curvature radius on the axle; k indicates the conic coefficient; and A4, A6, A8, A10, A12, A14 and A16 indicates the coefficients of the aspheric surface.
For convenience sake, the aspheric surface shown in the formula (7) shall be taken as the aspheric surfaces of all lens surfaces. However, the invention shall be not limited to the polynomial form of the aspheric surface shown in the formula (7).
Embodiment 1
The configuration structure diagram of the camera lens LA in the Embodiment 1 is shown in the FIG. 2. Moreover, the data including curvature radius of the object side surfaces and the imaging side surfaces, the center thicknesses of the lenses, the distances d among the lenses, refractive powers nd and abbe numbers of the lens L1-L6 in the Embodiment 1 are shown in the Table 1, wherein the camera lens LA is formed by the lens L1-L6; and the data including conic coefficients k and aspheric coefficients are shown in the Table 2.











TABLE 1






R
d
nd
vd






















S1
∞
 d0=
−0.300  






R1
1.35573
 d1=
0.568
nd1
1.5440
v1
56.00


R2
5.66391
 d2=
0.036






R3
4.39724
 d3=
0.226
nd2
1.6420
v2
22.40


R4
2.48185
 d4=
0.304






R5
−202.57998
 d5=
0.380
nd3
1.5440
v3
56.00


R6
−4.49053
 d6=
0.285






R7
−1.23264
 d7=
0.268
nd4
1.6420
v4
22.40


R8
−2.93353
 d8=
0.048






R9
1.58498
 d9=
0.541
nd5
1.5440
v5
56.00


R10
−2.50906
d10=
0.328






R11
−1.46094
d11−
0.264
nd6
1.5310
v6
56.00


R12
4.79577
d12=
0.400






R13
∞
d13=
0.210
nd7
1.5168
v7
64.17


R14
∞
d14=
0.257


















TABLE 2








conic coefficient
aspheric coefficient
















k
A4
A6
A8
A10
A12
A14
A16





R1
 3.0135E−01
−2.1408E−02
 1.2321E−02
−6.1047E−02
 1.2806E−01 
−3.3964E−01
 3.8684E−01
−2.1705E−01


R2
 3.3570E+01
−3.1978E−01
 4.5009E−01
−7.2140E−02
−7.8399E−01
 4.1839E−01
 6.1024E−01
−5.5334E−01


R3
 2.0612E+01
−3.9412E−01
 7.2451E−01
−4.4614E−01
−5.1344E−01
 5.7064E−01
 5.2830E−01
−6.5311E−01


R4
 6.3468E+00
−1.3403E−01
 2.0131E−01
−3.3469E−02
 9.7575E−02 
−1.2773E+00
 2.5019E+00
−1.1953E+00


R5
 0.0000E+00
−1.3413E−01
−1.6753E−01
−8.7467E−02
 3.4472E−01
 7.1132E−01
−3.9734E+00
 4.1347E+00


R6
−8.1071E+01
−1.5314E−01
−1.5237E−01
 1.3707E−01
 6.7483E−02 
−5.8845E−01
 6.7454E−01
−1.1167E−01


R7
−1.4351E+01
−3.0305E−01
 3.3129E−01
−1.5820E−01
−2.4236E−03
 1.2180E−01
−1.0198E−01
 2.6167E−02


R8
−3.9101E+00
−3.2656E−01
 2.8453E−01
 3.2599E−03
−4.5669E−02 
−1.2346E−02
 1.3538E−02
−1.9072E−03


R9
−2.1145E+01
−1.6728E−01
 8.2568E−02
−2.0614E−02
−3.6369E−02
 2.8634E−02
−1.0889E−02
 2.1745E−03


R10
−1.1944E+01
 1.0068E−01
−1.2407E−01
 7.0590E−02
−1.1658E−02
 8.6835E−03
−1.0556E−03
 2.9722E−05


R11
−3.3957E+00
 5.8763E−02
−8.9041E−02
 6.1385E−02
−2.0336E−02
 3.6057E−03
−3.3209E−04
 1.2545E−05


R12
−4.5330E+01
 4.9167E−03
−4.6739E−02
 3.0054E−02
−1.0603E−02
 2.1037E−03
−2.1592E−04
 8.8994E−06









The values in the embodiments 1 and 2 and the values corresponding to the parameters specified in the conditions (1)-(6) are shown in the subsequent Table 5.
The Embodiment 1 meets the conditions (1)-(6), as shown in Table 5.
See FIG. 3 for Longitudinal Aberration of the camera lens LA in the Embodiment 1, see FIG. 4 for Lateral Color Aberration of it, and see FIG. 5 for curvature of field and distortion of it. Further, the curvature of field S in the FIG. 5 is the one in the sagittal direction, and T is the one in the direction of meridian, as well as in the Embodiment 2. Moreover, the camera lens LA in the embodiment 1 involves the ultra-thin wide angle camera lens having high luminous flux as shown in FIGS. 3-5, wherein 2ω=80.2°, TTL/IH=1.420, Fno=1.90; therefore, it is no wonder that this lens has these excellent optical properties.
Embodiment 2
The configuration structure diagram of the camera lens LA in the Embodiment 2 is shown in the FIG. 6. Moreover, the curvature radius of the object side surfaces and the image side surfaces, the center thicknesses of the lenses, the distances d among the lenses, refractive powers nd and abbe numbers vd of the lens L1-L6 in the Embodiment 2 are shown in the Table 3, wherein the camera lens LA is formed by the lens L1-L6; and the conic coefficients k and aspheric coefficients are shown in the Table 4.











TABLE 3






R
d
nd
vd






















S1
∞
 d0=
−0.300  






R1
1.35578
 d1=
0.568
nd1
1.5440
v1
56.00


R2
5.66481
 d2=
0.036






R3
4.39527
 d3=
0.226
nd2
1.6420
v2
22.40


R4
2.48105
 d4=
0.304






R5
−199.86058
 d5=
0.379
nd3
1.5440
v3
56.00


R6
−4.49536
 d6=
0.285






R7
−1.23234
 d7=
0.268
nd4
1.6420
v4
22.40


R8
−2.93500
 d8=
0.048






R9
1.58898
 d9=
0.541
nd5
1.5440
v5
56.00


R10
−2.50121
d10=
0.328






R11
−1.46037
d11=
0.264
nd6
1.5310
v6
56.00


R12
4.79310
d12=
0.400






R13
∞
d13=
0.210
nd7
1.5168
v7
64.17


R14
∞
d14=
0.258


















TABLE 4








conic coefficient
aspheric coefficient
















k
A4
A6
A8
A10
Al2
A14
A16





R1
 3.0138E−01
−2.1397E−02
 1.2323E−02
−6.1058E−02
 1.2804E−01 
−3.3967E−01
 3.8676E−01
−2.1724E−01


R2
 3.3565E+01
−11977E−01
 4.5014E−01
−7.2076E−02
−7.8390E−01
 4.1852E−01
 6.1037E−01
−5.5324E−01


R3
 2.0628E+01
−3.9408E−01
 7.2458E−01
−4.4604E−01
−5.1337E−01
 5.7069E−01
 5.2837E−01
−6.5290E−01


R4
 6.3478E+00
−1.3402E−01
 2.0135E−01
−3.3332E−02
 9.7850E−02 
−1.2768E+00
 2.5028E+00
−1.1938E+00


R5
 0.0000E+00
−1.3417E−01
−1.6751E−01
−8.7094E−02
 3.4540E−01
 7.1216E−01
−3.9726E+00
 4.1353E+00


R6
−8.0959E+01
−1.5313E−01
−1.5220E−01
 1.3721E−01
 6.7484E−02 
−5.8850E−01
 6.7457E−01
−1.1144E−01


R7
−1.4353E+01
−3.0300E−01
 3.3130E−01
−1.5821E−01
−2.4307E−03
 1.2179E−01
−1.0201E−01
 2.6128E−02


R8
−3.8935E+00
−3.2663E−01
 2.8449E−01
 3.2497E−03
−4.5666E−02 
−1.2340E−02
 1.3544E−02
−1.9011E−03


R9
−2.1144E+01
−1.6729E−01
 8.2428E−02
−2.0676E−02
−3.6385E−02
 2.8635E−02
−1.0885E−02
 2.1776E−03


R10
−1.1921E+01
 1.0079E−01
−1.2403E−01
 7.0591E−02
−11661E−02
 8.6822E−03
−1.0560E−03
 2.9682E−05


R11
−3.3977E+00
 5.8779E−02
−8.9041E−02
 6.1384E−02
−2.0337E−02
 3.6057E−03
−3.3209E−04
 1.2547E−05


R12
−4.4704E+01
 4.9490E−03
−4.6738E−02
 3.0054E−02
−1.0604E−02
 2.1037E−03
−2.1592E−04
 8.8995E−06









The Embodiment 2 meets the conditions (1)-(6), as shown in Table 5.
See FIG. 7 for Longitudinal Aberration of the camera lens LA in the Embodiment 2, see FIG. 8 for Lateral Color Aberration of it, and see FIG. 9 for curvature of field and distortion of it. Moreover, the total angle of view is involved in the camera lens LA in the Embodiment 2 as shown in FIGS. 7-9, and the lens refers to the ultra-thin wide-angle camera lens having high luminous flux, wherein 2ω=80.2°, TTL/IH=1.42, Fno=1.90; therefore, it is no wonder that this lens has these excellent optical properties.
The values in all embodiments and the values corresponding to the parameters specified in the conditions (1)-(6) are shown in the Table 5. Moreover, the units including 2ω(°), f(mm), f1(mm), f2(mm), f3(mm), f4(mm), f5(mm), f6(mm), TTL(mm), LB(mm) and IH(mm) are shown in the Table 5, respectively.










TABLE 5






Embodiment 1
Embodiment 2
Condition


















f2/f
−2.766
−2.760
(1)


f3/f
2.508
2.506
(2)


(R1 + R2)/(R1 − R2)
−1.629
−1.629
(3)


(R5 + R6)/(R5 − R6)
1.045
1.046
(4)


(R3 + R4)/(R3 − R4)
3.591
3.592
(5)


d5/f
0.113
0.112
(6)


Fno
1.90
1.90



2ω
80.2
80.2



TTL/IH
1.420
1.420



f
3.364
3.371



f1
3.131
3.131



f2
−9.305
−9.304



f3
8.436
8.448



f4
−3.529
−3.526



f5
1.873
1.874



f6
−2.079
−2.078



TTL
4.115
4.115



LB
0.867
0.868



IH
2.897
2.897









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

## Claims

1. A camera lens comprising, in an order from an object side to an image side:
a first lens with positive refractive power;
a second lens with negative refractive power;
a third lens with positive refractive power;
a fourth lens with negative refractive power;
a fifth lens with positive refractive power; and
a sixth lens with negative refractive power; wherein the camera lens satisfies the following conditions (1) ̃(4):


−5.00≦f2/f≦−1.60  (1);



1.80≦f3/f≦5.00  (2);



−1.80≦(R1+R2)/(R1−R2)≦−1.30  (3);



0.70≦(R5+R6)/(R5−R6)≦1.50  (4);


where,
f: overall focal distance of the camera lens;
f2: focal distance of the second lens;
f3: focal distance of the third lens;
R1: curvature radius of the first lens' object side surface;
R2: curvature radius of the first lens' image side surface;
R5: curvature radius of the third lens' object side surface;
R6: curvature radius of the third lens' image side surface.

2. The camera lens as described in claim 1 further satisfying the following condition (5):


1.80≦(R3+R4)/(R3−R4)≦4.00  (5);

where,
R3: curvature radius of the second lens' object side surface;
R4: curvature radius of the second lens' image side surface.

3. The camera lens as described in claim 1 further satisfying the following condition (6):


0.07≦d5/f≦0.12  (6);

where,
f: overall focal distance of the camera lens;
d5: center thickness of the third lens L3.