Non-lens color holographic projection method

Abstract

The invention discloses a non-lens color holographic projection method. The non-lens color holographic projection method comprises the steps of sequentially arranging a spatial light modulator, a diaphragm and a projection screen, and arranging a red-green-blue three-color laser at the other side of the spatial light modulator, wherein the spatial light modulator is connected with a computer; determining the distance to the diaphragm from the spatial light modulator according to the distance to the spatial light modulator from the projection screen; decomposing a color image to three primary color component images, respectively calculating Fresnel diffraction to a holographic surface from the component images to obtain three complex amplitude holograms; combining the three complex amplitude holograms into a phase type hologram by wavelength multiplex coding; and loading the obtained phase type hologram into the spatial light modulator, irradiating the spatial light modulator by the three-color laser at different angles, reconstructing an image on the projection screen after a light wave passes through the diaphragm, and combining a final color image after the images are laminated. By the non-lens color holographic projection method, the projection display frame rate of the color image is improved, and high-resolution and large-size dynamic non-lens color holographic projection is achieved.

Description

Technical field [0001] The invention relates to a holographic projection method, in particular to a lensless color holographic projection method. Background technique [0002] Holographic projection technology is a new type of projection display technology based on the principle of diffractive optics. Generally, a laser with high coherence is used as a light source. When the laser irradiates a diffractive optical element (hologram), it undergoes diffraction propagation and interference in space to form a specific projection image. Holographic projection technology usually has the characteristics of high contrast and low power consumption, and has become an ideal technology for future projection display. The hologram is usually generated in a computer through programmed numerical calculation, which can flexibly adjust the distance and size of the projected image. [0003] The traditional projection display device usually contains many lenses or lens groups, so as to realize the im...

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Problems solved by technology

[0005] Purpose of the invention: The purpose of the invention is to propose a method based on two-step Fresnel diffraction algorithm, wavelength multiplexing phase encoding method and spatial filtering technology to solve the problem of speckle noise in the reconstructed image and the color display frame rate in the traditional lensless holographic projection method. Lensless color holographic projection method with low speed and other problems

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