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A phase-shifting point diffraction interferometer (PS/PDI) is applied for absolute surface figure measurement for large aperture optics. The intensity and phase distributions of measurement wavefront containing the surface figure profile are measured on the projection plane. The phase map gives the surface figure of the mirror. However, the wavefront reflected by the test mirror changes itself while propagating due to the surface figure of the mirror and the position of the point light source. The wavefront is different from the surface figure on the projection plane. For absolute surface profiling, the wavefront on the mirror has to be reconstructed from the measurement results. To reconstruct the wavefront digital holography has been studied. We have developed the numerical reconstruction method by using the Helmholtz-Kirchhoff formula. Spherical concave mirror measurements have been simulated to verify the availability. Ideal spherical mirror measurements, aspherical mirror measurements and a spherical mirror measurement in which the point light source was slightly displaced were simulated. As a result, the phase map on the projection plane did not fit the surface figure. It was also revealed that the light intensity distribution causes changes in the wavefront. In contrast, the reconstructed phase map on the mirror gave the real surface figure. For precise reconstruction the number of sampling on the projection plane must be increased.

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-A microcapsule diffuser of the transparent type is proposed to reduce the speckle noise generated on a laser display. This diffuser has a microcapsule that is secured between two transparent electrodes. The microcapsule contains light diffusion particles that are electrically charged. Because the particles in the microcapsules are moved by the electric field, the proposed device reduces speckle noise. This paper reports the results of one study of the device reliability.

We have successfully developed a new category of television, a laser TV, which uses a visible-ray laser. Our new laser TV has a color gamut that is approximately twice that of conventional liquid crystal TVs owing to the monochromaticity of the laser, which is one of the specifi c features of the laser system. The high efficiency of laser energy conversion, together with the optical systems optimized to our developed laser, managed to reduce the power consumption of the new laser TV to a level less than a half that of a liquid crystal television of the same size. On the other hand, the high coherency of the laser causes scintillation, and this degrades the quality of pictures. To solve this problem, we have succeeded in developing a new moving screen, which greatly contributes to the production of a laser TV system with high image quality.