Abstract: In the optical apparatus, the projection lens has a first lens group and a second lens group, the color synthesizing optical system has a transparent plate, dichroic mirrors and a plane mirror, the second lens group is disposed between the color synthesizing optical system and the polarization beam splitters, and the plane including the normal line of the plane of the transparent plate, the color synthesizing planes of the dichroic mirrors and the optical axis of the projection lens is perpendicular to the plane including the normal line of the polarizing and splitting planes of the polarization beam splitters and the optical axis of the projection lens.

Abstract: A projection lens includes sequentially from a screen side a first lens group which has a negative power, a second lens group which has a weaker power than that of the first lens group, a third lens group which has a positive power, a fourth lens group which has a positive power, and at least one transparent prism, wherein the fourth lens group is placed on the third lens group side of the transparent prism so as to be close to or in contact with the transparent prism. In the projection lens, a back focus of the main lens group is much longer compared with a focal length. A projection display apparatus using this projection lens is composed of one main lens group, three auxiliary lenses, and three polarizer-beam splitters, and a color combining optical system for combining three primary color components of red, green, and blue into one light beam is placed between the main lens group and the auxiliary lens.

Abstract: A liquid crystal panel includes a first substrate on which pixel electrodes are formed in a matrix pattern, a second substrate on which a counter electrode is formed, an ultraviolet reducing layer formed on one of the first and second substrates and corresponding to the matrix pattern of the pixel electrodes, and a polymer dispersion liquid crystal layer sandwiched between the first and second substrates. The polymer dispersion liquid crystal layer is cured by irradiating ultraviolet light from the side on which the ultraviolet reducing layer is formed such that the polymer dispersion liquid crystal layer arranged between the counter electrode and each pixel electrode has an average liquid crystal drop diameter which is larger than that arranged in other areas.

Abstract: A liquid crystal display panel includes a counter substrate having a counter electrode and a multi-layered dielectric film both formed thereon, and an array substrate formed with pixel electrodes and thin-film transistors serving as switching elements. A layer of polymer dispersed liquid crystal material containing a UV-curable resin component and a liquid crystal component is sealingly sandwiched between the counter and array substrates. A light shielding film is formed over each thin-film transistor. The multi-layered dielectric film is a laminated structure of alternating thin-films of SiO.sub.2 and HfO.sub.2. Since the multi-layered dielectric film is of a nature capable of transmitting UV-rays of light therethrough, the UV-curable resin component positioned underneath the multi-layered dielectric film can be cured during the manufacture.

Abstract: A polarization plane rotator, for executing rotation of the plane of polarization of linearly polarized light that is incident thereon with a predetermined angle of incidence, is formed of a transparent prism or an array of such prisms, each prism having a triangular cross-sectional shape, with first, second and third surfaces having respective lines of intersection that are mutually parallel. The linearly polarized light is incident on the first surface, to be reflected twice in succession at the second and third surfaces, to be emitted from the first surface with the plane of polarization rotated by 90.degree. and the direction of propagation altered. An optical thin film is formed on the second and third surfaces, for substantially reducing an amount of phase difference between the P and S polarization components which results from reflection, thereby ensuring that the emitted light is substantially completely linearly polarized.

Abstract: A polarization separation mirror is made by evaporation-depositing a first multi-layers thin film and a second multi-layers thin film respectively on both surfaces of a transparent substrate, the mirror acts as a polarization beam splitter by cementing it between two transparent prism bodies. By shifting the relative film thicknesses of the first multi-layers thin film and of the second multi-layers thin film, reflecting wavelength range for the S-polarization component is changed.

Abstract: A polarizer comprising; a substrate transparent to a light of actual use and optical thin films of a higher refractive index than that of said substrate deposited on both surfaces of said substrate. The substrate is arranged so as to receive the incident light obliquely thereto. When the incident angle and the thickness of the optical thin film are optimally selected, the transmittance for the P polarized light can be made approximately 100%, while that for the S polarized light very small. The polarizer can extract a substantially linearly polarized light from natural light, A projection image display system has the polarizer as its pre-polarizer. The polarizer is also useful for infrared radiation.

Abstract: A polarization beam splitter which includes a first prism, a second prism, and a dielectric multilayer film which is sandwiched between the first and second prisms is disclosed. The dielectric multilayer film comprising: a plurality of high refractive index layers having a refractive index higher than refractive indices of the first and second prisms; a plurality of intermediate refractive index layers having a refractive index lower than the refractive index of the high refractive index layers; and a plurality of low refractive index layers having a refractive index lower than the refractive index of the intermediate refractive index layers, a reference incident angle .theta..sub.0 of light which is incident on the dielectric multilayer film through the first or second prism being within a range of the following expression:.theta..sub.1 <.theta..sub.0 <.theta..sub.2where ##EQU1## where n.sub.H indicates the refractive index of the high refractive index layers, n.sub.

Abstract: A polarizer comprising; a substrate transparent to a light of actual use and optical thin films of a higher refractive index than that of said substrate deposited on both surfaces of said substrate. The substrate is arranged so as to receive the incident light obliquely thereto. When the incident angle and the thickness of the optical thin film are optimally selected, the transmittance for the P polarized light can be made approximately 100%, while that for the S polarized light very small. The polarizer can extract a substantially linearly polarized light from natural light. A projection image display system has the polarizer as its pre-polarizer. The polarizer is also useful for infrared radiation.