Abstract: A mirror comprises a transparent glass substrate and a dielectric multilayer film laminated on one surface (entrance surface) of the glass substrate. The dielectric multilayer film is formed by layers made of a high refractive index material and layers made of a low refractive index material which are alternately laminated, and is applied to a projection type display apparatus. The material and thickness of each layer are set so as to yield a polarization characteristic for causing reflected light to approach linearly polarized light.

Abstract: A projection type display apparatus includes a spatial light modulator, a polarizing beam splitter formed of members of a transparent material, and a projection optical system. The polarizing beam splitter includes a dielectric multilayer film, and a first transparent material member and a second transparent material member sandwiching the dielectric multilayer film. Each of the first and second transparent material members is made of a transparent material with a refractive index of at least 1.8 and with an absolute value of the photoelastic constant being no more than 1.5.times.10.sup.-8 cm.sup.2 /N for light of wavelengths 0.4 .mu.m to 0.7 .mu.m, incident to the polarizing beam splitter.

Abstract: A camera according to the present invention is so arranged that a half mirror is disposed in an optical path between a taking lens and a photographic film strip to be exposed so as to reflect a part of subject image incident thereinto. The thus reflected subject image is received by CCD, which converts it into electric image data. The image data is converted into binary codes, and the codes are written by a magnetic head in a magnetic layer provided on the back face of the photographic film strip. On the other hand, the image data received by the CCD is displayed for a photographer in a finder through a liquid crystal display at all times.