Research Of3D Coherent Display Based On Lcos Technology

With the development of all kinds of spatial light modulator (SLM), including acoustic optical spatial light modulator, liquid crystal spatial light modulator and the technology of digital micro-mirror and so on. Electro-controllable spatial light modulators have played an important role in the electro-holographic three dimensional displays. The technology of liquid crystal on silicon (Lcos), as an emerging display technology, has been regarded as the most potential technology which can be used in the coherent holographic3D display. The main purpose of this thesis is to realize the coherent holographic display using the Lcos panel as the display device. In order to achieve the purpose, some researching works are carried out, including theories and methods of computer holography, algorithms for calculating computer generated hologram (CGH), setting up an electro-holographic three dimensional display system with the Lcos panel and improving the quality of the reconstructed image. They are described in detail as follows:At the beginning, the physiological causes of three dimensional visual are reviewed. Some typical three dimensional display systems are compared and analyzed. Coherent holographic3D display as the holy grail of the3D display systems has been paid a lot of attention. Electro-holographic three dimensional display as a kind of coherent holographic3D display is better than the traditional display system in many respects. Lcos panel, as a spatial light modulator, plays an important role in the electro-holographic display system. The Lcos technical background and the advantages used in the electro-holographic display are analyzed.Using the equivalent grating model, the equivalent grating constant of the Lcos panel is measured which provide a basis for further research. Based on the physical parameters of the current Lcos panel, the capability to reconstruct image is discussed. The influence of the Lcos panel on the reconstructed image is analyzed from the mathematical point of view. The space-bandwidth product of the Lcos panel is calculated. The program of computer generated hologram is programed in the visual basic6.0of Microsoft development environment. On this basis, some methods to increase the efficiency of the program are proposed, the effects of which are analyzed and discussed.An electro-holographic display system using the Lcos panel as the core device is set up. When using the converging spherical wave as the reconstructed beam, the spectrum distribution on the lens focal plane is discussed. Based on that, a spatial filter is added in the reconstructed optic system in order to avoid the effect of the diffraction direct-current component, the effect of which is validated by the experiment. According to the principle of elementary hologram, the relationship between the recorded image and the reconstructed image is analyzed and the relationship between the viewing angle and the horizontal magnification is discussed. At last, the feasibility of the plan to set up an electro-holographic display system using the Lcos panel is verified and the dynamic reconstructed effect is achieved through human-computer interactions way.