Abstract: In a control unit, when a digital input audio signal level is equal to and beyond the first given level at a first time, a delay counter starts the counting operation, and when the digital audio signal level is equal to and beyond the second given level at a second time, an inherent delay time is obtained by calculating the difference between the first and second times, wherein the time difference is compared to the predetermined delay time of a delay memory unit to obtain a time lapse, so that a start ID is recorded at a third time decided by the time lapse after the second time, and thus the start ID signal is recorded at an appropriate position coincident with the starting head of the digital audio signal, thereby realizing a high speed search thereof without an omission of a head portion of the digital audio signal when the digital audio signal is reproduced.

Abstract: A rear-projection screen for a rear-projection image display comprises a Fresnel lens sheet (2) and a lenticular lens sheet (3), or a Fresnel lens sheet (2), a lenticular lens sheet (3) and a light absorbing sheet (4). The entrance surface (21) of the Fresnel lens sheet (2) or the entrance surface (41) of the light absorbing sheet (4) is formed by contiguously and vertically arranging a plurality of horizontally elongate lenticular lenses. The thickness of the Fresnel lens sheet (2) is approximately equal to that of the lenticular lens sheet (3). The entrance surface (31) and the exit surface (32) of the lenticular lens sheet (3) are formed by contiguously and horizontally arranging a plurality of vertically elongate lenticular lenses. Particles of a light diffusing material, which is essential to the prior art rear-projection screen, are not necessarily dispersed in the base sheet (30) of the lenticular lens sheet (3).

Abstract: An ultra-wide angle liquid crystal projector system comprising a light source, a liquid crystal panel, a curved screen, and a projection lens for projecting in accordance with light emitted by the light source an image formed on the liquid crystal panel onto the curved screen. The projection lens has a curvature of field substantially conforming to the shape of the curved screen and an angle of projection of at least 120 degrees. The projection lens is disposed with respect to the curved screen so that a distance from an exit surface of the projection lens to the curved screen is less than 3 meters.

Abstract: A rear-projection screen for a rear-projection image display comprising a Fresnel lens sheet (2) and a lenticular lens sheet (3), or a Fresnel lens sheet (2), a lenticular lens sheet (3) and a light absorbing sheet (4). The entrance surface (21) of the Fresnel lens sheet (2) or the entrance surface (41) of the light absorbing sheet (4) is formed by contiguously and vertically arranging a plurality of horizontally elongate lenticular lenses. The thickness of the Fresnel lens sheet (2) is approximately equal to that of the lenticular lens sheet (3). The entrance surface (31) and the exit surface (32) of the lenticular lens sheet (3) are formed by contiguously and horizontally arranging a plurality of vertically elongate lenticular lenses. Particles of a light diffusing material, which is essential to the prior art rear-projection screen, are not necessarily dispersed in the base sheet (30) of the lenticular lens sheet (3).

Abstract: In a projection lens device having at least two plastic lenses for magnification-projecting an original image displayed on a display screen onto a screen, one of the two plastic lens is convex at a center thereof toward the screen and concave at a periphery thereof, and the other lens has a weak positive refractive power toward the screen at a center thereof and a stronger positive refractive power at a periphery thereof. A variation of a lens power due to a change of a surrounding environment is cancelled out by the concave shape at the periphery of the one lens and the positive refractive power at the periphery of the other lens.

Abstract: A projection lens system for a projection type television having a cathode-ray tube with a panel having a fluorescent inner surface for projecting an image onto a screen. The projection lens system includes a plurality of lens groups, the lens group positioned at a side nearest to the cathode-ray tube including, in successive order from a side toward the screen, a lens having a concave surface on the screenn side a transparent medium, and the cathode-ray tube panel having a fluorescent inner surface, the lens group attenuating at least a part of a wavelength region of the light emitted on the fluorescent surface so as to improve contrast while reducing observance of a ghost image due to multiple reflection without substantial impairment in at least one of brightness and luminance. More particularly, the attenuation is provided by the concave lens having at least one surface dyed in a predetermined color.

Abstract: Disclosed is a projection lens system for use in an optical system for magnifying and projecting original images displayed on plural image display devices onto a screen through projection lenses provided in corresponding relation to the image display devices, which projection lens system comprises plural lens elements and in which according to colors or degrees of fineness of original images, the number of constituent lenses, or the shape of lens surface, or an effective aperture of at least one constituent lens element surface, or the number of constituent lenses and the shape of lens surface, or the number of constituent lenses and an effective aperture of at least one constituent lens element surface, or the shape of lens surface and an effective aperture of at least one constituent lens element surface, or the number of constituent lenses, the shape of lens surface and an effective aperture of at least one constituent lens element surface, are changed at a time.

Abstract: A projection type image display device provided with three projecting lenses projecting light emitted by cathode-ray tubes of different colors, red, green and blue, on a screen while enlarging an image is disclosed, in which clapper plates are disposed preferably in front of the red and the blue image source and the clapper plates have different shapes so as to obtain an image without the fluctuation in the color on the whole surface of the screen, even in the case where the distance from the cathode-ray tubes to the screen is shortened in order to reduce the size of the display device.

Abstract: A rear projection screen for use in a rear projection image display device comprises one or more sheet members through which light is sequentially transmitted from the side of a plane of incidence of the screen, the last sheet member comprising a transparent material as a base thereof, and a light diffusing layer provided on the side of a plane of emergence of the base. A light diffuser having a refractive index different from that of the base may be dispersed in the base so as to contrive a greater viewing angle. Further, a transperent binder for supporting the light diffuser dispersed in the light diffusing layer or the light diffuser itself may be colored in order to obtain a further enhanced contrast.

Abstract: In a projection system wherein an optical system comprising a first lens for correcting a spherical aberration dependent on the aperture length, a second lens for enlargement and a third lens for correcting a field curvature, projects an image reproduced on a CRT having a curved phosphor surface, onto a screen, the third lens is spaced from the CRT so that the region of the phosphor surface which again totally reflects a light which has been totally reflected by a screen-side surface of the third lens is limited to the edge portion of an effective region of the phosphor surface.

Abstract: In a video projector for projecting a video picture displayed on a Braun tube, the space between the Braun tube and a lens is filled with a medium having a refractive index substantially equal to those of both the glass faceplate of the braun tube and the material of the lens, and the medium is a silicon resin of the mixture of two liquids which is in liquid phase just after the mixing of two or three or above liquids but cured after lapse of a certain time into a gel state, and the lens is supported by a lens holder so that it can be moved freely along the optical axis within the lens holder.