35.2: Design of Hybrid Refractive/Reflective Projection Optics for Family Theatre

An ultra‐short focal projector equipped with a set of refractive lenses and an odd polynomial mirror is developed in this paper. Currently, short focal projectors generally employ a fisheye lens that produces wide field of view (WFOV). However, the lens distortion is inevitable so the design a projection optics with WFOV, small distortion and low f‐number is still the challenge for an ultra‐short focal projector system. The projector described in this paper overcomes these limitations by using a set of refractive lenses and an odd polynomial mirror. This enables projection optics with a focal length of −4.6 mm, an f‐number of 2.0, a WFOV of about 140° and a distortion of less than < 1 % to be presented. Results of the proposed projection optics will be described. Moreover, a portable projector based on light‐emitting diodes (LED) is proposed.