# Patent

## Title
Camera lens

## Abstract

A camera lens is disclosed. The camera lens includes five piece ultra-thin and high-luminous flux wide angle lenses with excellent optical properties 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 positive refractive power; a fifth lens with negative refractive power which are arranged in an order from an object side to an image side. The camera lens satisfies 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 five piece ultra-thin and wide angle lenses with excellent optical properties and with chromatic aberration sufficiently corrected is developed gradually. The camera lens mentioned in the proposal of prior reference documents 1, 2 is composed of five piece lenses which are arranged sequentially from object side 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 positive refractive power and a fifth lens with negative refractive power.
The camera lens disclosed in embodiment 1 ̃5 of the prior reference document 1 is composed of above mentioned 5 piece lenses, but shape of the first lens and the second lens is improper and ratio of center thickness of the fourth lens to overal focal distance of the camera lens is insufficient; so TTL/LH≧1.58 it is not sufficiently ultra-thin.
The camera lens disclosed in embodiment 1 ̃6 of the prior reference document 2 is composed of above mentioned 5 piece lenses, but shape of the second lens and refractive power distribution of the second lens is improper and ratio of center thickness of the fourth lens to overall focal distance of the camera lens is insufficient; so it is not sufficiently ultra-thin.
PRIOR REFERENCE DOCUMENTS
[Prior Reference Document 1] Japan Patent No. JP5513641;
[Prior Reference Document 2] Japan Patent Publication No. JP2015-225246.
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, and a fifth lens L5.
A glass plate GF is arranged between the fifth lens L5 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. Moreover, it shall be OK if no glass plate GF is arranged between the fifth lens L5 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 positive refractive power; the fifth lens has negative refractive power. Moreover, the surfaces of the five 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) ̃(6):

0.60≦f1/f≦0.75  (1);

−1.40≦f2/f≦−1.25  (2);

5.20≦f3/f≦20.00  (3);

−1.20≦(R1+R2)/(R1−R2)≦−0.88  (4);

0.06≦(R3+R4)/(R3−R4)≦0.50  (5);

0.19≦d7/f≦0.23  (6); where,

f: overall focal distance of the camera lens;

f1: focal distance of the first lens L1;

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;

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

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

d7: center thickness of the fourth lens L4.

The positive refractive power of the first lens L1 is specified in the condition (1). It is difficult for development of wide angle trend and hard to correct the aberration when the numerical range exceeds the lower limit specified in the condition (1) because the positive refractive power of the first lens L1 becomes too strong; on the contrary, when the numerical range exceeds the upper limit specified, the development of ultra-thin trend cannot be implemented easily because the refractive power of the first lens L1 becomes too weak
Therefore, numerical range of condition (1) should be set within the numerical range of the following condition (1-A) preferably,

0.65≦f1/f≦0.75  (1-A)

The negative refractive power of the second lens L2 is specified in the condition (2). Moreover, the problems, such as correction of chromatic aberration on axle and outside of axle, etc. cannot be implemented easily along development of ultra-thin and wide angle trend 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,

−1.38≦f2/f≦−1.28  (2-A)

The positive refractive power of the third lens L3 is specified in the condition (3). Moreover, chromatic aberration on axle and outside of axle cannot be cannot be easily corrected along development of ultra-thin 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,

5.80≦f3/f≦18.50  (3-A)

The shape of the first lens L1 is specified in the condition (4). Moreover, high order aberration like aberration of spherical surface cannot be corrected easily along development of ultra-thin and wide angle trend 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,

−1.10≦(R1+R2)/(R1−R2)<−0.88  (4-A).

Shape of the second lens L2 is specified in the condition (5). Moreover, chromatic aberration on axle cannot be corrected easily along development of ultra-thin and wide angle trend outside the range of the condition (5).
Therefore, numerical range of condition (5) should be set within the numerical range of the following condition (5-A) preferably,

0.08≦(R3+R4)/(R3−R4)≦0.30  (5-A)

Ratio of center thickness of the fourth lens to the overall focal distance of the camera lens is specified in condition (6). Moreover, the development of ultra-thin and wide angle trend cannot be implemented easily outside the range of the condition (6).
The fourth lens L4 has positive refractive power and meets the following condition (7).

0.50≦f4/f≦0.72  (7); where,

f: overall focal distance of the camera lens

f4: focal distance of the fourth lens L4

The positive refractive power of the fourth lens L4 is specified in the condition (7). The development of ultra-thin and wide angle trend is very effective though meeting the condition (7) when chromatic aberration on axle and outside of axle is sufficiently correct.
Therefore, numerical range of condition (7) should be set within the numerical range of the following condition (7-A) preferably,

0.68≦f4/f≦0.72  (7-A)

The camera lens also meets the following condition (8):

0.10≦d6/f≦0.13  (8); where,

f: overall focal distance of the camera lens;

d6: axial distance from the image side surface of the third lens L3 to the object side surface of the fourth lens L4.

Ratio of distance between the image side of the third lens L3 and object side of the fourth lens L4 to the overall focal distance of the camera lens is specified in condition (8). Moreover, the development of ultra-thin and wide angle trend of cannot be implemented easily outside the range of the condition (8).
Because five 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 five ultra-thin, wide angle lenses with excellent optional properties and with chromatic aberration sufficiently corrected.
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
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 glass plate GF's object side surface
R12: 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 surface 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
d14: axial distance from the image side surface of the fifth lens L5 to the object side surface of the glass plate GF
d11: center thickness of the glass plate GF
d12: 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 glass plate GF
νd: abbe number
ν1: abbe number of the first lens L1
ν2: abbe number of the second lens L2
ν3: abbe number of the third lens L3
ν4: abbe number of the fourth lens L4
ν5: abbe number of the fifth lens L5
ν6: 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 fifth lens L5;
IH: image height

y=(x2/R)/[1+{1−(k+1)(x2/R2)}1⁄2]+A4×4+A6×6+A8×8+A10×10+A12×12+A1 4×14+A16×16  (9);

wherein R indicates the curvature radius on the axle; k indicates the conical 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 (9) 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 (9).
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 R of the object side surfaces and the image side surfaces, center thicknesses of the lenses, the distances d among the lenses, refractive powers nd and abbe numbers v d of the lens L1-L5 in the Embodiment 1 are shown in the Table 1, wherein the camera lens LA is formed by the lens L1-L5; and the data including conic coefficients k and aspheric coefficients are shown in the Table 2.











TABLE 1






R
d
nd
v d






















S1
∞
d0 =
−0.180 






R1
 1.35953
d1 =
0.503
nd1
1.5441
v 1
56.12


R2
−25.07871
d2 =
0.051






R3
 −7.32685
d3 =
0.176
nd2
1.6614
v 2
20.41


R4
 4.96061
d4 =
0.235






R5
 8.51430
d5 =
0.250
nd3
1.6614
v 3
20.41


R6
 11.51459
d6 =
0.331






R7
 −3.73663
d7 =
0.683
nd4
1.5441
v 4
56.12


R8
 −1.00738
d8 =
0.397






R9
 −2.92369
d9 =
0.369
nd5
1.5352
v 5
56.12


R10
 1.72164
d10 =
0.400






R11
∞
d11 =
0.210
nd6
1.5168
v 6
64.17


R12
∞
d12 =
0.386


















TABLE 2








conic coefficient
aspheric coefficient
















k
A4
A6
A8
A10
A12
A14
A16





R1
0.0000E+00
−1.5468E−02
 3.9843E−02
−1.3445E−01
 2.7746E−02
 9.3728E−02
−6.7025E−03
−2.2270E−01


R2
0.0000E+00
 2.4333E−02
−1.1834E−02
 1.1584E−01
−3.0450E−01
−3.8007E−01
 1.5520E−01
 2.0929E−01


R3
0.0000E+00
 9.8486E−02
 1.0578E−01
−5.9097E−02
−5.3062E−02
−2.8456E−01
−5.6953E−01
 7.1206E−01


R4
1.9831E+01
−8.6962E−03
 9.4313E−02
 1.2775E−01
−1.7970E−01
−4.2463E−01
 4.6455E−01
−5.2451E−01


R5
−6.5269E+01 
−2.7516E−01
 6.0753E−02
−3.1090E−02
 1.0803E−01
 4.3608E−01
 4.6072E−01
−1.5845E+00


R6
1.5263E+02
−1.8153E−01
−1.6029E−02
 7.6326E−02
 9.2252E−02
 5.1078E−02
 1.7144E−02
−7.6890E−02


R7
4.7472E+00
 1.2587E−02
 1.1870E−02
−4.7958E−02
 1.4691E−02
 1.1574E−02
−1.4480E−02
 8.6493E−03


R8
−4.0911E+00 
−7.2353E−02
 1.0921E−01
−3.6773E−02
−3.7349E−03
−5.4880E−04
 2.3764E−03
−5.6258E−04


R9
−5.5985E+01 
−4.0675E−02
 1.1454E−02
 1.9687E−04
−3.1381E−04
 8.6437E−06
 5.9953E−06
−4.9808E−07


R10
−8.8696E+00 
−4.8083E−02
 1.3513E−02
−3.2483E−03
 4.2467E−04
−2.4186E−05
−7.6470E−07
 1.9123E−07









The values in the embodiments 1 and 2 and the values corresponding to the parameters specified in the conditions (1)-(8) are shown in the subsequent Table 5.
The Embodiment 1 meets the conditions (1)-(8), 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. As shown in FIGS. 3 ̃5, the camera lens in embodiment 1 has 2ω=82.7°, TTL/IH=1.360 and is aso wide angle and ultra-thin, it is no wonder why chromatic aberration on axle and outside of axle is sufficiently corrected and why it has 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, the refractive powers nd and abbe numbers vd of the lens L1-L5 in the Embodiment 2 are shown in the Table 3, wherein the camera lens LA is formed by the lens L1-L5; and the conical coefficients k and aspheric coefficients are shown in the Table 4.











TABLE 3






R
d
nd
v d





















S1
∞
d0 =
−0.200

















R1
 1.36884
d1 =
 0.568
nd1
1.5441
v 1
56.12


R2
−25.45040
d2 =
 0.051






R3
 −8.24155
d3 =
 0.187
nd2
1.6614
v 2
20.41


R4
 4.93656
d4 =
 0.232






R5
 9.06272
d5 =
 0.270
nd3
1.5843
v 3
28.25


R6
 11.89493
d6 =
 0.384






R7
 −3.55459
d7 =
 0.684
nd4
1.5441
v 4
56.12


R8
 −1.04484
d8 =
 0.423






R9
 −2.12352
d9 =
 0.354
nd5
1.5352
v 5
56.12


R10
 2.06274
d10 =
 0.400






R11
∞
d11 =
 0.210
nd6
1.5168
v 6
64.17


R12
∞
d12 =
 0.344


















TABLE 4








conic coefficient
aspheric coefficient
















k
A4
A6
A8
A10
A12
A14
A16





R1
 0.0000E+00
−1.1228E−02
 4.8772E−02
−1.3103E−01
 2.2305E−02
 9.3134E−02
 3.2386E−02
−1.8405E−01


R2
 0.0000E+00
 2.1295E−02
−5.5423E−03
 1.0277E−01
−3.1187E−01
−3.2562E−01
 2.8998E−01
 1.2459E−01


R3
 0.0000E+00
 7.7637E−02
 9.1720E−02
−6.6400E−02
−5.9573E−02
−2.7589E−01
−5.0087E−01
 8.2192E−01


R4
 1.8059E+01
−5.0009E−03
 5.9331E−02
 1.2324E−01
−1.3714E−01
−4.1329E−01
 3.2774E−01
−3.0315E−01


R5
−5.5587E+01
−2.7034E−01
 6.3896E−02
−3.1020E−02
 9.0252E−02
 4.0644E−01
 4.1014E−01
−1.6007E+00


R6
 1.5381E+02
−1.7099E−01
−1.5482E−02
 7.4048E−02
 8.7328E−02
 5.4437E−02
 2.2124E−03
−6.5681E−02


R7
 3.8407E+00
 1.8029E−02
 3.8627E−03
−4.9522E−02
 1.2681E−02
 1.2217E−02
−1.2901E−02
 5.9793E−03


R8
−3.7664E+00
−5.1010E−02
 1.0254E−01
−3.8829E−02
−3.4565E−03
 1.5361E−04
 2.6655E−03
−7.4401E−04


R9
−1.2488E+01
−3.7098E−02
 1.1830E−02
 1.5951E−04
−3.3083E−04
 5.3765E−06
 6.1556E−06
−3.3381E−07


R10
−1.5693E+01
−4.8709E−02
 1.2113E−02
−3.2384E−03
 4.2414E−04
−2.4197E−05
−6.7090E−07
 2.6604E−07









The Embodiment 2 meets the conditions (1)-(8), 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. As shown in FIGS. 7 ̃9, the camera lens in embodiment 2 has 2ω=78.9°, TTL/IH=1.400 and is also wide angle and ultra-thin, it is no wonder why chromatic aberration on axle and outside of axle is sufficiently corrected and why it has excellent optical properties.
The values in all embodiments and the values corresponding to the parameters specified in the conditions (1)-(8) are shown in the Table 5. Moreover, the units including 2ω(°), f (mm), f1 (mm), f2 (mm), f3 (mm), f4 (mm), f5 (mm), \TTL (mm), LB (mm) and IH (mm) are shown in the Table 5, respectively.










TABLE 5






Embodiment 1
Embodiment 1
Condition


















f1/f
0.731
0.688
(1)


f2/f
−1.362
−1.327
(2)


f3/f
14.647
17.995
(3)


(R1 + R2)/(R1 − R2)
−0.897
−0.898
(4)


(R3 + R4)/(R3 − R4)
0.193
0.251
(5)


d7/f
0.209
0.196
(6)


f4/f
0.714
0.710
(7)


d6/f
0.101
0.110
(8)


Fno
2.20
2.30



2ω
82.7
78.9



TTL/IH
1.360
1.400



f
3.265
3.497



f1
2.386
2.405



f2
−4.447
−4.642



f3
47.823
62.930



f4
2.330
2.482



f5
−1.970
−1.899



TTL
3.991
4.107



LB
0.996
0.954



IH
2.934
2.934









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 positive refractive power;
a fifth lens with negative refractive power; wherein
the camera lens satisfies the following conditions (1) ̃(6):


0.60≦f1/f≦0.75  (1);



−1.40≦f2/f≦−1.25  (2);



5.20≦f3/f≦20.00  (3);



−1.20≦(R1+R2)/(R1−R2)≦−0.88  (4);



0.06≦(R3+R4)/(R3−R4)≦0.50  (5);



0.19≦d7/f≦0.23  (6); where,


where,
f: overall focal distance of the camera lens;
f3: focal distance of the first 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;
R3: curvature radius of the second lens' object side surface;
R4: curvature radius of the second lens' image side surface;
d7: center thickness of the fourth lens.

2. The camera lens as described in claim 1 further satisfying the following condition (7):


0.50≦f4/f≦0.72  (7);

where,
f: overall focal distance of the camera lens;
f4: focal distance of the fourth lens.

3. The camera lens as described in claim 1 further satisfying the following condition (8):


0.10≦d6/f≦0.13  (8);

where,
f: overall focal distance of the camera lens;
d6: axial distance from the image side surface of the third lens to the objects side surface of the fourth lens.