Patent Application
20190227283
This application claims the priority benefit of Japanese Patent Application Ser. No. 2018-006967 filed on Jan. 19, 2018, the entire content of which is incorporated herein by reference.
The present disclosure relates to the field of camera lens, and particularly to a mobile phone camera assembly, a WEB camera lens and the like that use camera elements such as high-pixel CCD or CMOS, which is composed of five lenses with excellent optical characteristics, and of which an F number (hereinafter referred to as Fno) is less than 2.05, TTL (optical length)/IH (image height)≤1.5 which is deemed as ultrathin.
In recent years, various types of camera devices that use camera elements such CCD and CMOS are increasingly widely used. As the camera elements are being miniaturized while getting higher-performanced, ultrathin camera lenses with excellent optical characteristics and bright Fno are more eagerly demanded.
Technological development associated with the ultrathin 5-lensed camera lens with excellent optical characteristics and bright Fno is gradually proceeding. A proposal is that the camera lens is composed of five lenses which, in sequence, starting from an object side, are 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.
A camera lens disclosed in related technologies is the above-described camera lens composed of five lenses, but the configuration of refractive power of the fourth lens, and a ratio between center thickness of the fourth lens and the focal distance of the entire camera lens are insufficient and thus Fno=2.25 and the brightness is insufficient.
The camera lens disclosed in related technologies is the above-described camera lens composed of five lenses, but the configuration of refractive power of the second lens, a shape of the second lens, and the ratio between the center thickness of the fourth lens and the entire camera lens are insufficient, and thus Fno≥2.25 and the brightness is insufficient.
One embodiment of a camera lens according to the present disclosure is described with reference to the drawings.
The first lens L1 has a positive refractive power, the second lens L2 has a negative refractive power, the third lens L3 has a negative refractive power, the fourth lens L4 has a positive refractive power and the fifth lens has a negative refractive power. In order to solve the aberration problem, preferably, surfaces of the five lenses are designed as aspherical.
The camera lens LA is a camera lens that meets the following formulas (1)-(4):
-10.00≤f3/f≤−7.00 (1);
0.60≤f4/f≤0.90 (2);
0.80≤(R3+R4)/(R3−R4)≤1.50 (3);
0.22≤d7/f≤0.40 (4);
wherein,
f: focal distance of the entire camera lens;
f3: focal distance of the third lens;
f4: focal distance of the fourth lens;
R3: curvature radius of object side surface of the second lens;
R4: curvature radius of image side surface of the second lens;
d7: center thickness of the fourth lens.
Conditional formula (1) defines the negative refractive power of the third lens L3. Beyond the scope of the conditional formula (1), it is difficult to develop to ultrathin camera lens with bright Fno.
Here, it is the best that the values of the conditional formula (1) are set within the range shown by the conditional formula (1-A) as follows:
−9.00≤f3/f≤−8.00 (1-A).
Conditional formula (2) defines the positive refractive power of the fourth lens L4. Beyond the scope of the conditional formula (2), it is difficult to develop to ultrathin camera lens with bright Fno.
Here, it is the best that the values of the conditional formula (2) are set within the range shown by the conditional formula (2-A) as follows:
0.65≤f4/f≤0.75 (2-A).
Conditional formula (3) defines the shape of the second lens L2. Beyond the scope of the conditional formula (3), it is difficult to develop to ultrathin camera lens with bright Fno.
Here, it is the best that the values of the conditional formula (3) are set within the range shown by the conditional formula (3-A) as follows:
1.15≤(R3+R4)/(R3−R4)≤1.35 (3-A).
Conditional formula (4) defines the ratio between the center thickness of the fourth lens L4 and the focal distance of the entire camera lens. Beyond the scope of the conditional formula (4), it is difficult to develop to ultrathin camera lens with bright Fno.
Here, it is the best that the values of the conditional formula (4) are set within the range shown by the conditional formula (4-A) as follows:
0.25≤d7/f≤0.30 (4-A).
The second lens L2 has a negative refractive power that meets the following formula (5):
−2.00≤f2/f≤−1.40 (5);
wherein,
f: focal distance of the entire camera lens;
f2: focal distance of the second lens;
Conditional formula (5) defines the negative refractive power of the second lens L2. Beyond the scope of the conditional formula (5), it is difficult to develop to ultrathin camera lens with bright Fno.
Here, it is the best that the values of the conditional formula (5) are set within the range shown by the conditional formula (5-A) as follows:
−1.75≤f2/f≤−1.50 (5-A).
The first lens L1 has a positive refractive power that meets the following formula (6):
−1.20≤(R1+R2)/(R1-R2)≤−0.80 (6);
wherein,
R1: curvature radius of object side surface of the first lens;
R2: curvature radius of image side surface of the first lens.
Conditional formula (6) defines the shape of the second lens L1. Beyond the scope of the conditional formula (6), it is difficult to develop to ultrathin camera lens with bright Fno.
Here, it is the best that the values of the conditional formula (6) are set within the range shown by the conditional formula (6-A) as follows:
−1.10≤(R1+R2)/(R1−R2)≤−1.00 (6-A).
Since the five lenses constituting the camera lens LA meet the above-described configurations and conditional formulas, it is possible to provide an ultrathin camera lens with excellent optical characteristics and bright Fno≤2.05.
The camera lens LA of the present disclosure will be described below by way of embodiments. Signs described in the embodiments are as follows. Distances, radiuses and center thicknesses are in millimeters.
y=(x2/R)/[1+{1−(k+1)(x2/R2)}½]+A4×4+A6×6+A8×8+A10×10+A12×12+A14×14+A16×16 (7)
wherein R is on-axis curvature radius, k is conic coefficient, and A4, A6, A8, A10, A12, A14 and A16 are aspherical coefficients.
For sake of convenience, the aspherical surface shown in formula (7) is used for the aspherical surface of each lens surface. The present disclosure, however, is not limited to the aspherical polynomial form illustrated by the formula (7).
Table 5 which will be presented later shows the values in embodiments 1 and 2 corresponding to the values of the parameters specified in the conditional formulas (1) to (6).
As shown in Table 5, embodiment 1 meets the conditional formulas (1) to (6).
The axial aberration of the camera lens LA in embodiment 1 is shown in
As shown in Table 5, embodiment 2 meets the conditional formulas (1) to (6).
The axial aberration of the camera lens LA in embodiment 2 is shown in
Table 5 shows various kinds of the values in embodiments and values corresponding to the parameters defined in the conditional formulas (1) to (6). The units of the various kinds of the values shown in Table 5 are: 2ω(°), f (mm), f1 (mm), f2 (mm), f3 (mm), f4 (mm), f5 (mm), TTL (mm), LB (mm), IH (mm).
The protection scope of the present disclosure is not limited by the above-described embodiments. Any modification or variation to the content disclosed in the present disclosure made by skilled people in the existing technology shall be included in the protection scope disclosed by the Claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-006967 | Jan 2018 | JP | national |
