Abstract: A projection type display device comprising a light source for irradiating a light valve, a light valve wherein pixels are arranged in delta matrix, each pixel containing color pixels for the three primary colors and a composite color of red (R), green (G) and blue (B) being displayed on each pixel, a projection lens for projecting the visual images formed on the light valve by receiving the light emitted from the light valve, and a screen including a lenticular lens which has a periodic structure in one direction and on which projected images are formed, which is characterized in that, given the pitch PL of the periodic structure of the lenticular lens and the pitch P of the projected image on the lenticular lens in the direction corresponding to the periodic structure, the pitches PL and P satisfy the equation (1) below when 0.41<m1<0.57,(P/PL).multidot.m1=n+1/2 (provided, n is a natural number).

Abstract: A power amplifying module has a package formed by welding a package bottom plate being a package substrate of a generally flat plate shape with a cap being a metal package cap of a generally rectangular box shape. A wiring substrate of a generally flat plate shape is placed on the package bottom plate and this wiring substrate is covered by the cap. There are two through holes formed in the wiring substrate and two heat spreaders of a generally flat plate shape are positioned in portions exposed through the through holes on the package bottom plate. Semiconductor devices sealed with a resin or the like are set by soldering or the like on respective surfaces of these heat spreaders.

Abstract: In an electronic component, an electronic circuit board having an electronic element mounted on the major surface is mounted on a metal frame. The electronic circuit board is covered with a metal lid fitted on the metal frame and contained in a metal package constituted by the metal frame and the metal lid. At least at one notched portion is formed at least at one end of the electronic circuit board. A positioning projection formed on the metal frame engages with the notched portion. The mechanical precision and electrical characteristics are improved, so that an electronic component particularly excellent in high-frequency characteristics, which can be manufactured in simple manufacturing process, can be obtained.

Abstract: A power amplifying module has at least one heat spreader mounted on a package substrate and exposed through a through hole provided in a wiring substrate, and at least one semiconductor chip forming a power amplifying circuit is mounted in a bare chip state on a surface of the at least one heat spreader as electrically connected to an electronic circuit pattern on the wiring substrate. Each of the package substrate and at least one heat spreader is made of a material having a thermal conductivity larger than that of a material making the wiring substrate. The module thus formed can emit the heat generated by the power amplifying module to the outside at high efficiency, thus achieving the power amplifying module with high performance and high reliability.

Abstract: A rear-projection screen having at least a Fresnel lens and a light-diffusing member, and is characterized by having vertical-direction light diffusion properties greater at its upper and lower end portions than at its middle portion. For example, the light-diffusing member contains light-diffusing fine particles and has a vertical lenticular lens that diffuses light in the vertical direction, provided on the light-incident surface of the Fresnel lens. This decreases the rainbows caused by misdirected light and also improves the brightness at the border, without causing a lowering of peak gain.

Abstract: A double-faced lenticular lens sheet including at least one incident side lens formed on a first face of the double-faced lenticular lens sheet; and at least one corresponding emergent side lens formed on a second opposite face of the double-faced lenticular lens sheet; wherein light rays incident on the at least one incident side lens parallel to an optical axis thereof pass through the lenticular lens sheet and emerge from the at least one emergent side lens; an angle of refraction .theta.1 is formed by a straight line parallel to an optical axis of the at last one incident side lens and a light ray refracted by an incident plane passing through the lenticular lens sheet; an angle of refraction .theta.2 is formed by a straight line parallel to an optical axis of the at least one emergent side lens and the light ray refracted by and emitted from an emergent plane; .DELTA..theta.1 is an absolute value of the angle of refraction .theta.1 on the incident plane; .DELTA..theta.

Abstract: A lenticular lens sheet comprising lengthwise long lenticular lenses formed on the light incident-side surface and light emergent-side surface thereof, the lenticular lenses being constituted of cylindrical lenses each having a long dimension in the top and bottom direction of a screen when used, and satisfying0.30.ltoreq..vertline.i.sub.0 (.theta..sub.H).vertline..ltoreq.0.36when parallel light rays are made incident on the surface of its incident-side lens at horizontal incident angles of 0.degree., -11.degree. and +11.degree. and the emergent luminances of the respective light rays are standardized by evaluating the emergent luminance at an emergent-side horizontal visual angle 0.degree. to be 1, and the emergent luminances of the respective light rays at a horizontal visual angle .theta..sub.H .degree. are respectively represented by I.sub.0 (.theta..sub.H), I.sub.-11 (.theta..sub.H) and I.sub.+11 (.theta..sub.H), and when .vertline..theta..sub.H .vertline..ltoreq.40.degree.

Abstract: A rear-projection image display device comprising a light source, a display element for visual images, a projection lens and a screen for viewing visual images projected on the screen from the rear, wherein the ratio d/a between the diameter d of the exit pupil of the projection lens and the projection distance a is 0.06 or less, said screen whereon visual images are displayed includes at least two diffusion elements, and light-diffusing fine particles are dispersed in one of the two diffusion elements which is closest to the viewer.

Abstract: A lenticular lens provided on the viewer side of a transmission type screen is composed of at least two layers, that is, a surface layer and a base layer at least one of which contains a light dispersing material, and a visible light absorbing material is mingled in at least one of these two layers, or in the light dispersing material, thereby enhancing the image contrast of the transmission type screen.

Abstract: This invention provides a high-speed FET with a sufficiently high output current, and an FET having a high mobility of channel electrons and a high electron saturation rate. For this purpose, in this invention, a buffer layer, a first channel layer, a first spacer layer, a second channel layer, a second spacer layer, a third channel layer, and a capping layer are sequentially epitaxially grown on a semi-insulating GaAs semiconductor substrate. Drain and source regions are formed, and a gate electrode is formed to Schottky-contact the capping layer. Drain and source electrodes are formed to ohmic-contact the drain and source regions. Extension of a surface depletion layer from the substrate surface to a deep portion is prevented by the third channel layer closest to the substrate surface. For this reason, a sufficient quantity of electrons for forming a current channel are assured by the second and first channel layers.

Abstract: In a rear-projection screen comprising a Fresnel lens and a light-diffusing member containing light-diffusing fine particles, it is intended to decrease the moire and to give no dark feeling at the border even when projection systems are set in a short projection distance. For this end, in the rear-projection screen of the present invention, the thickness of the light-diffusing member is made larger at the border than at the center of the rear-projection screen, or the concentration of the light-diffusing fine particles contained in the light-diffusing member is made larger at the border than at the center so that the rear-projection screen can have light diffusion properties greater at its border than at its center. Here, any of a flat plate, a flat sheet and a lenticular lens sheet can be used as the light-diffusing member.

Abstract: A lenticular lens provided on the viewer side of a transmission type screen is composed of at least two layers, that is, a surface layer and a base layer at least one of which contains a light dispersing material, and a visible light absorbing material is mingled in at least one of these two layers, or in the light dispersing material, thereby enhancing the image contrast of the transmission type screen.

Abstract: In a rear-projection screen comprising a Fresnel lens and a light-diffusing member such as a lenticular lens sheet, a rise angle in a central region of the Fresnel lens is smaller than a rise angle in an intermediate region thereof (e.g., the former is not larger than 3.degree. and the latter is larger than 3.degree. ). The rise angles may preferably gradually increase from the central region of the Fresnel lens toward the intermediate region thereof. The central region of the Fresnel lens may preferably be a region extending within the range of from 1/4 to 1/3 from the middle point of a diagonal of the rear-projection screen. Such a Fresnel lens is effective for improving white uniformity in the intermediate region of the rear-projection screen and eliminating color corn in the central region thereof.

Abstract: A double-sided lenticular lens sheet has an entrance lens layer and an exit lens layer, at least said exit lens layer containing light-diffusing fine particles, and has parameters satisfying the following expressions (I) and (II). ##EQU1## wherein t.sub.1 represents a thickness of the entrance lens layer; t.sub.2, a thickness of the exit lens layer; .DELTA.n.sub.1, a difference in refractive index between the thermoplastic resin and the light-diffusing fine particles in the entrance lens layer; .DELTA.n.sub.2, a difference in refractive index between the thermoplastic resin and the light-diffusing fine particles in the exit lens layer; c.sub.1, a weight concentration of the light-diffusing fine particles in the entrance lens layer; c.sub.2, a weight concentration of the light-diffusing fine particles in the exit lens layer; .rho..sub.1, a gravity of the light-diffusing fine particles in the entrance lens layer; .rho..sub.2, a gravity of the light-diffusing fine particles in the exit lens layer; d.sub.

Abstract: The present invention provides a process for producing a blazed diffraction grating by using a transmission modulation diffraction grating as a photomask in photolithography. The photomask is composed of a relief modulation diffraction grating (A) made of a transparent material and a blazed diffraction grating (B) made of a material containing a ray absorbing agent. The diffraction grating (A) and the diffraction grating (B) are mated with each other through their grating surfaces.