Hitachi, Ltd.

Takahiko Yoshida

Hiroki Yoshikawa

Koji Hirata

Masayuki Muranaka

Isao Yoshizaki

Atsuo Osawa

Kiyoshi Wada

Shigeru Mori

Tooru Numata

Tetsu Ohishi

Shigeru Inaoka

Koji Suso

Toshimitsu Watanabe

Yasunori Kobori

Toshihiko Gotoh

Kazunari Nakagawa

Akira Takahashi

Yutaka Matsuda

Yoshimasa Yokoyama

Nobuhiro Konuma

Hideo Tanide

Mitsuo Okimoto

Maki Furui

Satoshi Ishizuka

Atsuo Ohsawa

Tohru Mori

Yutaka Matuda

Tutomu Simada

Naoko Kubo

Kohsuke Ozeki

Yoshinori Matsumura

Yasuhiko Komatsu

A multi-display apparatus includes a plurality of rear projection-type display devices each in which projection light from image sources is projected through projection lenses onto a rear projection surface of a rear projection screen to form a picture image on a front viewing surface of the rear projection screen, the plurality of rear projection-type display devices being combined together in contiguous relation to one another to form a large screen. An overall front viewing surface of the large screen is formed into a concave surface curved both in a horizontal visibility angle direction and a vertical visibility angle direction. A light-absorbing portion is formed on the front viewing surface of the rear projection screen, and the light-absorbing portion absorbs projection light which passes through one rear projection screen, and is incident as external light on another rear projection screen, thereby preventing a picture image from being degraded.

Multi-display apparatus

A rear projection type image display apparatus having an arrangement that a projection distance of a projection lens thereof is shortened and a density of mounting of parts relating to an optical system and an electric system is made higher. Furthermore, a width of a rear portion of a housing of the rear projection type image display apparatus is reduced rearwards at any position from the upper portion to the lower portion thereof, and the lower portion of a back cover is depressed inwards. Thus, a space required to install the rear projection type image display apparatus can be reduced, the rear surface of the apparatus can be disposed on a wall without any gap when the apparatus is installed along the wall, and the overall body of the apparatus can be received deep into a corner of walls when the apparatus is installed at the corner.

Rear projection type image display apparatus

A transmission screen for a rear projection type image display apparatus having at least one image generation source for displaying images, at least one projection lens for enlarging and projecting images displayed on the at least one image generation source onto a rear portion of the transmission screen for display. The transmission screen of the image display apparatus enables display of the images projected onto the transmission screen with a contrast of at least 70. Further, the transmission screen enables display with a field angle within a range of at least 72.degree. to less than 100.degree.. The transmission screen also includes a glossy light absorbing layer and a substantially smooth mirror surface at a light exit surface thereof.

Rear projection type image display apparatus and transmission type

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). The rear-projection image display provided with this rear-projection screen has satisfactory focusing characteristics and enhanced vertical directional characteristics and is capable of displaying an image in high brightness and high contrast.

Rear-projection screen and a rear projection image display employing the

A rear-projection screen for a rear-projection image display apparatus comprises a Fresnel lens sheet, a first lenticular lens sheet, and a second lenticular lens sheet or a Fresnel lens sheet, first and second lenticular lens sheets and a light absorbing sheet. A light entrance surface of the first lenticular lens sheet or a light exit surface thereof, or both of these surfaces are formed by contiguously and vertically arranging a plurality of horizontally elongate lenticular lenses. A thickness of the first lenticular lens sheet is selected to be the thinner than thicknesses of the Fresnel lens sheet, the second lenticular lens sheet, and the light absorbing sheet. The entrance surface and the exit surface of the second lenticular lens sheet are formed by contiguously and horizontally arranging a plurality of vertically elongate lenticular lenses. Particles of a light diffusing material are not necessarily dispersed in the base sheet of the second lenticular lens sheet. The rear-projection image display apparatus provided with this rear-projection screen has satisfactory focusing characteristics and enhanced vertical directional characteristics and is capable of displaying an image in high brightness and high contrast.

Rear-projection type image display apparatus and rear-projection type

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). The rear-projection image display provided with this rear-projection screen has satisfactory focusing characteristics and enhanced vertical directional characteristics and is capable of displaying an image in high brightness and high contrast.

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.

Temperature compensating lens system for projection television

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.

Projection lens system for projection type television

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.

Video projector with optical color balance

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.

Optical system for projection type image display device

A signal-processing circuit of a heat-sensitive recording apparatus comprising a temperature detector for detecting the temperature near a heat-sensitive head is disclosed, in which an energization code train read from a ROM for storing the energization time-concentration characteristics corresponding to the .gamma. characteristic of the inking paper is corrected in accordance with the head temperature, and a print is produced in accordance with the energization code train thus corrected.

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Miura, Japan

Takahiko Yoshida