Device and method for inhibiting laser speckles and laser display projection system

Abstract

The invention discloses a device and method for inhibiting laser speckles and a laser display projection system. The device comprises a plurality of noncoherent lasers, an optical fiber coupler and an optical fiber bundle. Multiple paths of light beams output by the lasers are coupled into sub optical fibers of the optical fiber bundle through the optical fiber coupler. The light beams transmitted in the sub optical fibers are called sub light beams. The adjacent sub light beams of the same frequency output by the output end of the optical fiber bundle have the preset distance in space. The sub light beams of the same frequency irradiate a screen at different angles through a projection system due to the set preset distance, so that speckle patterns observed by human eyes are independent from one another. According to the device, the coherence of the light beams is lowered through the noncoherent lasers, and thus the speckle contrast is lowered; the sub light beams are distributed according to the angle diversification of the speckles at the output end of the optical fiber bundle, and the independent speckles are superposed in the space to lower the speckle contrast; the speckle inhibiting effects of the two methods can be superposed, and the speckle contrast is lowered to a greater extent.

Description

technical field [0001] The invention relates to the field of laser projection display, in particular to a device and method for suppressing laser speckle, and also to a laser display projection system. Background technique [0002] Laser projection display technology has the advantages of high brightness and large color gamut. As a new generation of display technology, it has attracted great attention from the scientific and industrial circles. However, the laser has the characteristics of strong coherence, the strong coherence of the laser will cause the speckle effect, and the speckle effect will seriously affect the quality of the displayed image, and the speckle effect is difficult to be effectively eliminated, so the speckle effect Introduction has become the most important problem restricting the development of laser projection display technology. [0003] In response to this technical problem, the main way to suppress speckle in the industry is to increase the laser ...

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Problems solved by technology

However, the laser has the characteristics of strong coherence, the strong coherence of the laser will cause the speckle effect, and the speckle effect will seriously affect the quality of the displayed image, and the speckle effect is difficult to be effectively eliminated, so the speckle effect The introduction has become the most important problem restricting the development of laser projection display technology

[0003] In response to this technical problem, the main way to suppress speckle in the industry is to increase the laser bandwidth or the diversity of laser wavelengths. At present, a mixed light source formed by laser and other incoherent light (such as LED) appears on the market, but this requires the sacrifice of the light source. The brightness or saturation of the laser will affect the quality of the display image; the cost of the laser with a large line width is high, and the transmission power and efficiency are low, so it cannot be widely used

[0004] In addition, there is also a method of vibrating the screen to "boil" the speckle field to suppress speckle in the market. Although this method is simple and easy to implement, the effect of speckle suppression depends heavily on devices other than the projection system, such as the screen , but it is not easy to realize the vibration of the screen with hard material or too large size, so this method is not suitable for projection display equipment without fixed screen. This suppression method has poor suppression effect and practical problems

[0005] The suppression methods mentioned above all have great limitations, especially for applications such as high-brightness and high-gain displays. Due to the limitations of conditions such as laser heat and aperture increase, the effects that existing suppression methods can achieve limited

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