Title :
Compound Speckle Characterization Method and Reduction by Optical Design
Author :
Tong, Zhaomin ; Chen, Xuyuan ; Akram, Muhammad Nadeem ; Aksnes, Astrid
Author_Institution :
Inst. for Microsyst. Technol., Vestfold Univ. Coll., Borre, Norway
fDate :
3/1/2012 12:00:00 AM
Abstract :
Speckle and the compound speckle can be reduced by angle diversity. In laser projection displays, simple, low cost and efficient speckle reduction techniques require smart optical design . Using a MEMS scanner together with a condenser lens, laser beams with different illumination angles are obtained on the diffuser surface with low speckle contrast ratio (CR). After homogenizing within a rod integrator, the speckle field illuminates a display panel, and is projected onto the screen which forms the compound speckle. Characterization method to evaluate the compound speckle reduction efficiency is analyzed and discussed in a simplified optical system. The preliminary speckle reduction is demonstrated in a commercial projector where a 600 mW green laser has been used as the illumination source, and the compound speckle CR is brought down from 0.38 to 0.14.
Keywords :
colour displays; laser beams; lasers; lenses; micromechanical devices; optical projectors; optical scanners; speckle; MEMS scanner; angle diversity; commercial projector; compound speckle characterization; compound speckle reduction efficiency; condenser lens; diffuser surface; green laser; illumination angle source; laser beam; laser projection display panel; low speckle CR; low speckle contrast ratio; power 600 mW; rod integrator; smart optical design; Adaptive optics; Compounds; Educational institutions; Lasers; Lenses; Optical imaging; Speckle; Angle diversity; compound speckle; laser projection displays; speckle reduction;
Journal_Title :
Display Technology, Journal of
DOI :
10.1109/JDT.2011.2168384