Abstract: A display apparatus is provided with a plurality of display device, at least one of which is a semitransparent display; and a fixing device for fixing the plurality of display devices to be placed along a front-rear direction on a viewer's line of sight each other, wherein a relationship between the spacing L(mm) between image planes of adjacent of the plurality of display devices and the length S(mm) of diagonal lines of the two display devices satisfies a predetermined condition.

Abstract: An optical pickup device for reading information recorded on an optical disc, the device having a semiconductor laser, a half mirror and a light-receiving element. The semiconductor laser and the half mirror are attached to each other via a grating, and the light-receiving element is attached on the surface of the half mirror.

Abstract: A projection type picture display apparatus, includes a light source; a polarizing beam splitter capable of reflecting or transmitting an incident light; a decomposing/synthesizing prism assembly capable of receiving a reflected light from the polarizing beam splitter to decompose the incident light into red, green and blue lights, also capable of receiving reflected red, green and blue lights to synthesize these lights so as to produce a synthesized light; a plurality of reflective type liquid crystal displays capable of receiving, modulating and reflecting red, green and blue lights; a projection optical system capable of receiving a picture light passing through the polarizing beam splitter to project an enlarged picture on a screen.