Projection type display apparatus

A projection type display apparatus is arranged to be able to implement both brightness-priority display and color-reproduction-priority display by itself. In the display apparatus, white light from a light source 1 is separated into beams of three colors by a color separation optical system comprised of a combination of dichroic mirrors DM1, DM2, total reflection mirrors M1, M2, M3, etc., and the beams of the three colors are made incident to liquid-crystal display units 8R, 8G, 8B. After that, the beams are combined by a dichroic prism 9 and images of the liquid-crystal display units 8R, 8G, 8B are projected by a projection lens 10. In this display apparatus, a dichroic filter DF for transmitting light in a region not less than a certain wavelength (for example, about 600 nm) but intercepting light in the other region is arranged so as to be able to be put into or out of an optical path immediately before the liquid-crystal display unit 8R. When the dichroic filter DF is not put in the optical path, the light in the wavelength region not less than about 570 nm is used as projection light. When the dichroic filter DF is put in the optical path, the light in the region not less than about 600 nm is used as projection light in the red band.

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What is claimed is:

1. A projection type display apparatus which has a brightness-priority display mode and a color-reproduction-priority display mode and in which light from a light source isseperated into a plurality of light beams of mutually different colors, the light beams of the respective colors are guided into corresponding pixel groups among a plurality of pixel groups, and the light beams of the respective colors from the pluralityof pixel groups are projected,

wherein purity of at least one color is made variable by use of an optical element which is adapted to transmit light in a wavelength region exceeding a predetermined wavelength and intercept light in the remainder in the visible region or whichis adapted to transmit light in a wavelength region below a predetermined wavelength and intercept light in the remainder in the visible region.

2. A projection type display apparatus which has a brightness-priority display mode and a color-reproduction-display mode and in which light from a light source is seperated into a plurality of light beams of mutually different colors, the lightbeams of the respective colors are guided into corresponding pixel groups among a plurality of pixel groups, and the light beams of the respective colors from the plurality of pixel groups are projected, said display apparatus including an opticalelement which is adapted to transmit light in a wavelength region exceeding a predetermined wavelength and intercept light in the remainder in the visible region or which is adapted to transmit light in a wavelength region below a predeterminedwavelength and intercept light in the remainder in the visible region enhance purity of a predetermined color,

wherein said optical element is so arranged as to be able to be insertable into and retractable from a predetermined optical path and/or is so arranged as to be tiltable with respect to the predetermined optical path.

3. A projection type display apparatus which has a brightness-priority display mode and a color-reproduction-display mode and which comprises:

a plurality of image display elements;

a first optical system for separating light from a light source into a plurality of light beams of mutually different colors and guiding the light beams of the respective colors into corresponding elements among the plurality of image displayelements; and

a second optical system for combining light from the light beams of the respective colors from the plurality of image display elements, said display apparatus projecting the light of the colors combined by the second optical system,

wherein said projection type display apparatus includes an optical element which is adapted to transmit light in a wavelength region exceeding a predetermined wavelength and intercept light in the remainder in the visible region or which isadapted to transmit light in a wavelength region below a predetermined wavelength and intercept light in the remainder in the visible region so as to enhance purity of a predetermined color out of said colors, and said optical element is so arranged asto be able to be insertable into and retractable from a predetermined optical path and/or said optical element is so arranged as to be able to be tiltable with respect to the predetermined optical path.

4. The projection type display apparatus according to claim 3, wherein said predetermined optical path is an optical path between a dichroic mirror group of the first optical system and the light source.

5. The projection type display apparatus according to claim 3, wherein said predetermined optical path is an optical path defined by a dichroic mirror group of the first optical system.