LED数字投影机短焦投影物镜设计

为实现LED 数字投影机短距离内投影出更大的画面，文中针对此类投影机的结构特点，通过理论计算和ZEMAX 光学设计软件的优化，开发设计一款适用于LED 光源0.7 in（1 in=2.54 cm）单芯片数字投影机的短焦投影物镜。给出工作波长为462~625 nm、全视场角为84、相对孔径为1:2.4、焦距为10 mm、后工作距离大于20 mm 的镜头设计实例。镜头有较好的成像质量， 在分辨率极限40 lp/mm 处， 0.7 视场以内的MTF 值均大于0. 5，全视场畸变量的绝对值小于1.5%，像质优良。设计结果显示，文中提出的设计方法有利于降低投影系统成本，实现产业化生产。

Design of short-focus projection lens for LED digital projectors

To achieve LED digital projectors project in a short distance with the bigger picture projection, according to the structural characteristics of such projectors, a short focal digital projection lens for 0.7 inch DLP projectors was designed and a design example of a lens, whose operating wavelength was 462-625 nm,full field of view angle was 84, relative aperture was 1:2.4, focal length was 10 mm and back focal length was greater than 20 mm was given on the basis of the theoretical calculation and the optimization of optical design software ZEMAX. Its MTF in all fields less than 30 is higher than 0.5 at the limiting spatial frequency of 40 lp/mm. The absolute value of the full field of view distortion of the lens was less than 1.5% ,the image quality is very good. Analytical results show that the design can decrease the production costs of the projecting system and promote the technological industrialization.