| Summary: | 碩士 === 國立臺北科技大學 === 光電工程系研究所 === 104 === Because laser is better than LED and incandescent light source in color gamut and directionality due to its properties of coherence and narrow handwidth, we can replace the other two light sources with laser in applications of display. In particular, laser has the potential in headmound display and micro-projector for the compact configuration as the light source. In the study, we used a phase-only SLM (Spatial light modulation) to replace three parts of laser projector system : beam shaping、speckle suppression and image display which decrease volume of system to reduce the volume of the projector .
In our system, we switched phase images in high speed by SLM to replace a high frequency harmonic shacking diffusor which is most often used in laser projector. We first design DPE (Diffraction phase element) by using IFTA ( Interative fourier transform algorithm ) and then obtained these DPE for SLM. The SLM was separated into two parts, the left part to generate DPE for scattering grating and light beam shaping, and the right part to display DPE. The projected images were generated from the diffraction of the DPEs.By taking advantage of human vision persistence, we switch phase images in high speed for speckle suppression so that we can get our properties integrate three systems in one device. This study can reduce a lot of system volume. The results we obtained that the speckle contrast of all displayed images were approximately 0.8. After superpositioning images, all parameters decreased obviously and approximately reduced to 0.23. The result revealed that our system performed a high efficiency in projecting images and suppressing speckle.
In the further study we hope to improve the image quality and combine three color laser light RGB to the white light source. It can play a broadcast better quality.
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