The Preparation Of Liquid Crystal Light Valve With Nc-Si/a-Si:H Column Composite Photoconductor

The principle and the application of Liquid Crystal Light Valve (LCLV) and the development of the photoconductor of LCLV have been reviewed in this paper. The growth mechanism of amorphous silicon film is analyzed. The resolution of the photoconductor that is affected by the lateral diffusion of the photo-carrier in photoconductor layer is also analyzed. The fabrication techniques of the LCLV with nc-Si/a-Si:H column composite photoconductor are researched in detail.The lateral diffusion of the photo-carrier in photoconductor layer is one of the important factors of affecting the resolution of LCLV. The transfer of the carrier in photoconductor is anisotropy owing to the column structure of the film is anisotropy. On the basis of the new concept suggested in this paper, the maximum diffusion length in the lateral direction of the photo-carrier in the photoconductor (which is related to the resolution of LCLV directly) as function of conductivities of both in lateral and normal directions in the film can be obtained as the expression as following.The nc-Si/a-Si:H photoconductor of LCLV deposited and crystallized at low temperature of exactly 250 C stack column structure by Al inducing a-Si:H. The ratio of light conductivity to dark conductivity of the nv-Si/a-Si:H photoconductor is 103, and the light conductivity of nc-Si/a-Si:H photoconductor in the normal is 2-4 times more than that in the lateral. It will be known from the obtained expression of the resolution of photoconductorthat the column microstructure is benefit to reduce the carrier diffusion in the lateral direction and increase the resolution of the photoconductor.The blocking-layer and the dielectric mirror separate the write beam and the read beam, and the dielectric mirror reflects the read light also. In order to separating the write beam and the read beam quietly, and reflecting the read bean in the most limit. The optimal combination of the blocking layer and dielectric mirror is ascertained by the research of the optical performance of the blocking layer and the dielectric mirror. It is that the thickness of the blocking layer is more than 1.3um and the layer-number of the dielectric is 9. The combination of the multiplayer-film is the primary problem which presence at the fabrication of LCLV. In this paper, the reason of the break-off of the films is analyzed, and the problem has been solved.The function of the liquid crystal is modulating the read beam. It has shown that the alignment of Liquid Crystal (LC) will affect the behavior of the beam modulation of LCLV. The better the alignment, the better the performance of the beam modulation. The technical of fabrication of a good alignment of liquid crystal is studied in this paper, such as the time and the speed of spinning, the temperature and the time of the solidifying. In this paper, the technical of the rubbing is also studied and good films are prepared.The LCLV with nc-Si/a-Si:H columnar composite photoconductor is fabricated successfully in this work. The high quality image obtained by using nc-Si/a-Si:H column composite photoconductor LCLV and shows the resolution about 5001p/inch.