| dc.description.abstract | This paper uses eight digital photographic lens designs to analyze the overall length of the lens and the curved imaging surface, which are two designs of VGA, one design of 1 million pixels, four designs of 2 million pixels, and one design imaging on a curved surface of 2 million pixels.
In the two designs of VGA, increasing the half field angle from 20 degrees to 30 degrees make the effective focal length shorter, so the overall length is from 12.964 mm to 8.439 mm. Then select the smaller pixel size and reduce the imaging height to do the 1 million and the first design of 2 million pixels. The overall length of the lens is 5 mm and 2.65 mm, respectively. In the second design of 2 million pixels, the half field angle was increased to 32 degrees under the requirement of relative illumination, which shortened the overall length of the lens to 2.447 mm. In the third and fourth designs of 2 million pixels, shorten the back focal length and discuss the relationship between the power, the principal plane spacing, the thickness, the refractive index and the second principal plane of the lens. The overall length of the lens is 2.14 mm and 2 mm, respectively.
When the overall length of the lens is thinner, the chief ray angle will be larger, so the relative illumination decreases. When the field curvature also increases, the image quality decreases. Therefore, there is a limit to shortening the overall length. In the design imaging on a curved surface of 2 million pixels, the radius of curvature of the image surface is -6.318 mm, which corrects the problem of the chief ray angle too large, and compensates for the aberration caused by the field curvature, so that the image quality is improved.
| en_US |