Super Wide Angle Projection Lens for Laser Display

摘要

Recently ,super wide angle projection lens are widely used, for the market of slim projection TV and front projector of slow throw ratio is increasing rapidly. However, in conventional refractive projection optics,the maximum field angle is at most 100° because of the large distortion and lateral color aberration with wide angle. To solve this problem, the interrelation of parameters of projection lens was analyzed and an initial conventional spherical system was achieved to fulfill the fundamental performance, then its distortion was corrected by the aspheric surface depositing far from the optical pupil and a triple lens was used to solve the problem of chromatic aberrations. Using Zemax software, we designed a super wide angle projection lens, with super short focus of 4.76mm, super wide angle of 126° FOV. Simulation shows that the MTF at 721p/mm is greater than 0.6 in the central field and 0.4 in the full field; the maximal distortion is less than 0.9%. The prototype of the lens is fabricated and was installed in our newly-built laser LCOS projection TV and front projetion. The laser LCOS front projection has only a throw ratio of 0.28, which is very difficult to achieve for all refractive projection lens.