Patent Grant
10775595
This application claims the priority benefit of Japanese Patent Applications Ser. No. 2018-186239 filed on Sep. 30, 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, a field of view (hereinafter referred to as 2ω) is greater than 85° which is called as a wide angle, TTL (optical length)/IH (image height)≤1.35 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, wide angle and bright Fno are more eagerly demanded.
Technological development associated with the ultrathin 5-lensed camera lens with excellent optical characteristics, wide angle 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 positive 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 a difference between Abbe numbers of the second lens and fourth lens, and of the second lens and fifth lens, a ratio between focal distances of the second lens and fourth lens, and a ratio between center thicknesses of the second lens and first lens are insufficient, and thus the ultrathinization and the Fno brightness are insufficient.
The camera lens disclosed in related technologies is the above-described camera lens composed of five lenses, but the difference between Abbe numbers of the second lens and fourth lens, and a ratio between center thicknesses of the second lens and first lens are insufficient, and thus the ultrathinization and the Fno brightness are 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 positive 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)-(5):
28.00≤v2−v3≤40.00 (1);
28.00≤v2−v4≤40.00 (2);
28.00≤v2−v5≤40.00 (3);
1.80≤f2/f4≤2.00 (4);
0.63≤d3/d1≤0.66 (5);
wherein,
Conditional formula (1) defines a difference between Abbe numbers of the second lens L2 and third lens L3, conditional formula (2) defines a difference between Abbe numbers of the second lens L2 and fourth lens L4, and conditional formula (3) defines a difference between Abbe numbers of the second lens L2 and fifth lens L5.
Beyond the scope of the conditional formulas (1) to (3), it is difficult to correct on-axis and off-axis chromatic aberration in the case of wide angle, ultrathiness and bright Fno.
Conditional formula (4) defines a ratio between the focal distance f2 of the second lens L2 and the focal distance of the fourth lens L4. Beyond the scope of the conditional formula (4), it is difficult to be ultrathinized in the case of wide angle and bright Fno.
Conditional formula (5) defines a ratio between the center thickness d3 of the second lens L2 and the center thickness d1 of the first lens L1. Beyond the scope of the conditional formula (5), it is difficult to be ultrathinized in the case of wide angle and bright Fno.
The second lens L2 has a positive refractive power that meets the following formula (6):
2.95≤R3/R4≤3.20 (6);
wherein,
Conditional formula (6) defines a ratio between the curvature radius R3 on the object side of the second lens L2 and the curvature radius R4 on an image side of the second lens L2. Beyond the scope of the conditional formula (6), it is difficult to be ultrathinized in the case of wide angle and bright Fno.
The third lens L3 has a negative refractive power that meets the following formula (7):
−2.70≤R5/R6≤−1.00 (7);
wherein,
Conditional formula (7) defines a ratio between the curvature radius R5 on the object side of the third lens L3 and the curvature radius R6 on an image side of the third lens L3. Beyond the scope of the conditional formula (7), it is difficult to be ultrathinized in the case of wide angle and bright Fno.
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, a field of view greater than 85°, and bright Fno.
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.
For sake of convenience, the aspherical surface shown in formula (8) 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 (8).
Table 7 which will be presented later shows the values in embodiments 1 to 3 corresponding to the values of the parameters specified in the conditional formulas (1) to (7).
As shown in Table 7, embodiment 1 meets the conditional formulas (1) to (7).
The axial aberration of the camera lens LA in embodiment 1 is shown in
As shown in Table 7, embodiment 2 meets the conditional formulas (1) to (7).
The axial aberration of the camera lens LA in embodiment 2 is shown in
As shown in Table 7, embodiment 3 meets the conditional formulas (1) to (7).
The axial aberration of the camera lens LA in embodiment 3 is shown in
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 |
|---|---|---|---|
| 2018-186239 | Sep 2018 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 9557535 | Liao | Jan 2017 | B1 |
| 10215955 | Lin | Feb 2019 | B2 |
| 20120154929 | Tsai | Jun 2012 | A1 |
| 20150268448 | Kubota | Sep 2015 | A1 |
| 20160004042 | Kubota | Jan 2016 | A1 |
| 20160054543 | Nabeta | Feb 2016 | A1 |
| 20190243105 | Yan | Aug 2019 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20200103629 A1 | Apr 2020 | US |
