초록 ▼

A color filter which, in a reflection type color picture projector using a polarized light component as a projection light, improve the utilization factor of light and a color picture display device using the same color filter are provided. The color filter 3 using a transmission type hologram diffr

A color filter which, in a reflection type color picture projector using a polarized light component as a projection light, improve the utilization factor of light and a color picture display device using the same color filter are provided. The color filter 3 using a transmission type hologram diffracts and spectroscopically separates P polarized light components related to respective primary colors and condenses them to pixel electrodes 13r, 13g, and 13b on the side of an LCD panel 1. A reflection light which is modulated by an optical modulator 16 on the side of the LCD panel 1 and becomes S polarized light component is incident on the color filter 3. The color filter 3 transmits the S polarized light component and uses it as the projection light. Since the color filter 3 can diffract a P polarized light component at diffraction efficiency of about 100% while restricting the diffraction efficiency of S polarized light component to about 3%, which is substantially advantageous compared with diffraction of S polarized light component, the utilization factor of light can be improved

대표청구항 ▼

[ What is claimed is:] [1.] A color filter provided with hologram means for spectrally diffracting an incident light into a plurality of light beams of different wavelength ranges, and selectively condensing the plurality of light beams on respective plurality of picture element electrodes correspon

[ What is claimed is:] [1.] A color filter provided with hologram means for spectrally diffracting an incident light into a plurality of light beams of different wavelength ranges, and selectively condensing the plurality of light beams on respective plurality of picture element electrodes corresponding to the different wavelength ranges, wherein the hologram means is arranged so that the thickness t of the hologram and the modulation amount .DELTA.n of diffractivity is set under condition wherein P polarized components of the incident light, in a center wavelength of the different wavelength ranges and having a vibration plane parallel to an incident plane, are diffracted at approximately maximum diffraction efficiency at a predetermined incident angle of the incident light, and S polarized components of the incident light, in a center wavelength of the different wavelength ranges and having a vibration plane vertical to an incident plane, are diffracted such that a difference between the maximum diffraction efficiency of the P polarized components and the diffraction efficiency of the S polarized components is not less than 30%, with the diffracted P polarized components formed as the plurality of light beams to be converged on the plurality of picture element electrodes corresponding to the different wavelength ranges and wherein polarization directions of the P polarized components and the S polarized components are orthogonal to each other.