Projection system with laser speckle removal function

Abstract

The invention provides a projection system with a laser speckle removal function. The system consists of a laser lighting system and two imaging systems, wherein, the laser lighting system composed of an RGB three-color laser and a uniform light tube provides a uniform lighting source for LCOS imaging; each imaging system composed of a beam-splitting prism, an LCOS chip, a drive circuit and an imaging lens forms an LCOS image on a random phase plate with high transmittance; when the random phase plate rotates in a high speed, the LCOS image thereon is formed on a screen through a projection lens, and outgoing beams of the random phase plate can be changed from linearly polarized light into elliptically polarized light due to different random phases thereof by adopting the random phase plate with a certain double refraction property; and by means of a time average principle and polarized light speckle characteristics, laser speckles can be greatly reduced to provide good image quality.

Description

technical field [0001] The invention relates to a projection system with the function of eliminating laser speckles. Background technique [0002] The characteristics of laser monochromaticity, strong directionality and high brightness make laser as a light source for projection display have the advantages of vivid picture color, clear image, and suitable for large-screen display. However, due to its good monochromaticity and long coherence length, various interference effects will occur on the optical surfaces of the projection system, forming a large number of background stray interference fringes and speckle noise. reduce. In order to improve the image quality of laser projection display, the design of suppressing laser speckle is very necessary. [0003] Among the published patents such as 200510089116.8 and 200510115472.2, such as image 3 , as shown in 4, are all lighting systems that effectively reduce or eliminate speckle by dividing the beam emitted from the laser...

AI Technical Summary

Problems solved by technology

[0003] Among the published patents such as 200510089116.8 and 200510115472.2, such as image 3 , as shown in 4, are all lighting systems that effectively reduce or eliminate speckle by dividing the beam emitted from the laser source into sub-beams and averaging the sub-beams temporally or spatially, but this type of lighting system will suffer from diffractive optical elements Factors such as processing will cause a certain depolarization effect, which will lose part of the energy and reduce the utilization rate of laser energy if LCOS or LCD is used as the image modulation component

In addition, there is a traditional lighting device for eliminating laser speckle disclosed in US Patent No. 6,248,381, and the principle is similar. In structure, he uses an optical fiber bundle to eliminate laser speckle. The coupling efficiency is relatively low, which will lose part of the energy, and the efficiency of removing speckle with different phases is reduced

Images