The DLP Catadioptric Super Short Distance Optical Engine With LED Illumination

A review of the current situation of the super short focus projector technology is first carried out, discussed the advantages and the good market prospect of the short focus projector in comparison with the traditional projector. Besides, an introduction of several main stream products is carried out, and the deficiencies of the products are pointed out. A non-uniform grid target tessellation method and Parametric Optimization Method for the design of free-form lens are introduced. A review of the current design methods of the super short focus projector technology is then carried out. The advantage and disadvantage of each method are also pointed out. Based on which, we pointed out the problems to solve in this paper. The imaging and aberration control theory of the catadioptric imaging system is first detailed. Then the imaging relationship of the rotational reflector imaging system is detailed. Based on which, the construction method for the catadioptric imaging system is discussed. Then the aberration correction method is detailed. A general construction method for the rotationally symmetric ultra-short distance catadioptric projector is also proposed. Based on the methods proposed above, a DLP Catadioptric Super Short Distance Optical Engine with LED illumination is designed and a prototype is manufactured. The imaging performance of the Super Short Distance projector prototype is excellent. The image sharpness is high and the distortion is very small. The system has good tolerance and good color expression, and the total flux on the screen reaches 3901m.The novel ideas of this paper are listed as follow:(1) A fast aberration correction method for the catadioptric imaging system is proposed.(2) A general construction method for the rotationally symmetric ultra-short distance catadioptric projector is proposed.(3) A Non-uniform grid target tessellation method for the design of lens group with rectangular uniform illumination is proposed.(4) A DLP Catadioptric Super Short Distance Optical Engine with LED illumination is designed and a prototype is manufactured with excellent performance and tolerance.