With Screen Or Absorption Filter Patents (Class 348/786)
  • Patent number: 11485052
    Abstract: A resin product including an antireflection surface includes a plurality of first concave portions, a plurality of second concave portions, and a component surface. The first concave portions have opening widths equal to or larger than 1 ?m and equal to or smaller than 300 ?m. The second concave portions are formed on each of the plurality of first concave portions and have opening widths equal to or larger than 10 nm and equal to or smaller than 1 ?m. The component surface is configured to surround each of the plurality of first concave portions.
    Type: Grant
    Filed: July 5, 2019
    Date of Patent: November 1, 2022
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Toshimitsu Nagoya, Makoto Kojima, Kei Oikawa, Yukiya Enokida, Takashi Endo, Osamu Morisaki
  • Patent number: 10394077
    Abstract: A backlight module including a light source, an optical wavelength conversion film, a first group of optical films, and a second group of optical films is provided. The light source is adapted to emit a first light. The optical wavelength conversion film is adapted to convert the first light into a second light with a different wavelength. The first group of optical films is disposed between the light source and the optical wavelength conversion film. The optical wavelength conversion film is disposed between the first group of optical films and the second group of optical films, wherein a ratio of a transmittance of the second group of optical films for the second light to a transmittance of the first group of optical films for the first light is larger than or equal to 45%. Thus, the backlight module has a uniform light-emitting color.
    Type: Grant
    Filed: July 27, 2015
    Date of Patent: August 27, 2019
    Assignee: Au Optronics Corporation
    Inventors: Chi-Sheng Chang, Jian-Li Huang, Wei-Chun Chung, Su-Yi Lin
  • Patent number: 9952621
    Abstract: A display apparatus includes a display module and a front case. The display module displays images. The display module includes a boss fixing member having a combination hole. The front case covers a first surface of the display module and has a first boss that is inserted into the combination hole to combine the front case to the display module. The first boss is formed at inside edges of the display module. The boss fixing member is positioned within the edges of the display module which define the outdimension of the display module.
    Type: Grant
    Filed: April 8, 2011
    Date of Patent: April 24, 2018
    Assignee: SAMSUNG DISPLAY CO., LTD.
    Inventors: Hyun-chul Jeong, Jae-hwan Chun, Jong-ho Won, Sung-won Chung, Jung-ki Kim, Sung-Sun Han, Yu-kwan Kim, Jeong-Ki Kim
  • Patent number: 8427768
    Abstract: An optical filter for compensating for color shift is provided in front of a display panel of a display device. The optical filter includes a background layer and a green wavelength absorption pattern provided with a predetermined thickness on the background layer. The green wavelength absorption pattern absorbs a green wavelength of light. The green wavelength absorption pattern contains a material that absorbs a green wavelength of light in the range of 510 nm to 560 nm, and can also contain a white light absorbing material. A green's complementary color absorbing part absorbs a wavelength of light complementary to green, and contains at least one of a material absorbing a blue wavelength of light in the range of 440 nm to 480 nm and a material absorbing a red wavelength of light in the range of 600 nm to 650 nm.
    Type: Grant
    Filed: September 21, 2009
    Date of Patent: April 23, 2013
    Assignee: Samsung Corning Precision Materials Co., Ltd
    Inventors: Seong Sik Park, Seung Won Park, Sung Nim Jo, In Sung Sohn, Sang Cheol Jung, Ji Yoon Yeom, Eui Soo Kim
  • Patent number: 7922336
    Abstract: A light source device for a display device for projecting an image on a screen is provided, the light source device for display device including a light source unit operable to output light; an image outputting unit operable to output an image by giving an image signal to the light; and a control circuit operable to switch the image output from the image outputting unit between a normal image and a mirror reversed image formed by reversing the normal image right and left by controlling the image signal, such that outputting type is switched between a front projection in which the image is projected onto the screen from a front on the same side as the viewing side, and a rear projection in which the image is projected onto the screen from a rear plane on the opposite side to the viewing side.
    Type: Grant
    Filed: February 28, 2006
    Date of Patent: April 12, 2011
    Assignee: Panasonic Corporation
    Inventors: Toshifumi Yokoyama, Ken'ichi Kasazumi
  • Patent number: 7826634
    Abstract: According to one embodiment, a front frame forms a cabinet, and a display screen of an image display unit is arranged to be exposed from an opening at the center thereof. A frame forming portion is located at the lower part of the front frame, and sound emitting units which open elongatedly in a longitudinal direction of the frame forming portion are formed. A cabinet surface is formed continuously to the bottom side of the opening and is tilted and retreated while being bent in a direction of the back face of the front frame as it goes downwards.
    Type: Grant
    Filed: June 9, 2006
    Date of Patent: November 2, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Takayuki Soga
  • Patent number: 7329977
    Abstract: The invention relates to a discharge lamp with a reflector (1) and a burner (2), wherein the reflector (1) comprises at least a reflective contour (3) and a hollow reflector neck (4), the burner (2) is arranged in centered manner in the reflector (1) and the reflector (1) and the lower part (2.1) of the burner (2) are connected firmly together by a mechanical fastening unit and, during assembly, the burner (2) may be guided through the reflector neck (4), starting with its upper part (2.2), and the mechanical fastening unit exhibits such play in the x, y and z directions that the burner (2) can be brought into a defined position relative to the reflector during assembly.
    Type: Grant
    Filed: February 17, 2003
    Date of Patent: February 12, 2008
    Assignee: Koninklijke Philips Electronics, N.V.
    Inventors: Nicasius Gerardus Van Gennip, Wilfried Emunds, Michael Haacke
  • Patent number: 7324169
    Abstract: Provided are a projection optical system, a projection television, and a method of manufacturing a lens included in the projection optical system. The projection optical system includes lenses for projecting color beams onto a screen. A color filter layer, absorbing at least one of the color beams, is coated on the surface of at least one of the lenses.
    Type: Grant
    Filed: July 1, 2004
    Date of Patent: January 29, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Seok-il Yoon, Sung-gi Kim, Gyu-hwan Hwang, Young-Il Kah
  • Patent number: 7149033
    Abstract: An improved light beam combiner is disclosed that creates a more uniform light source across the UV, Visual, and NIR range. It is an optical mechanical device made up of a standard high low dielectric thin film which, when placed at a 45 degree angle between a Deuterium lamp and a Halogen or Tungsten lamp, reflects the UV portion of a Deuterium lamp and passes the visual portion while also allowing the visual energy of a Halogen or Tungsten lamp to pass resulting in a more uniform light source for use in spectroscopy.
    Type: Grant
    Filed: October 28, 2004
    Date of Patent: December 12, 2006
    Assignee: Ocean Optics, Inc.
    Inventor: Philip E. Buchsbaum
  • Patent number: 7055960
    Abstract: A rear projection display device includes an image generator, a reflector, a screen and a light shield disposed between the reflector and the screen. The image engine emits image beams among which ineffective ones are blocked by the light shield while effective ones are reflected on the screen via the reflector, thereby increasing the image forming performance of the displace device. The light shield is mounted on an adjusting device having an adjusting element. After the rear projection display device has been assembled, an angle and position of the light shield can be adjusted by means of rotating the adjusting element to further help the light shield to block the ineffective beams.
    Type: Grant
    Filed: April 14, 2004
    Date of Patent: June 6, 2006
    Assignee: Coretronic Corporation
    Inventors: Kun-Rong Chang, Kuo-Wen Chen
  • Patent number: 6900945
    Abstract: A lenticular lens sheet 4 comprises a plurality of lens elements of incidence 21 arranged on the incidence side, and a plurality of lens elements of emergence 22 arranged on the emergence side. The light that has passed through each lens element of incidence 21 converges via the protruding apex of the corresponding lens element of emergence 22. The lens plane of the center portion C of each lens element of emergence 22, the width of this portion C being a half of the total lens width L (i.e., L/2), is in the shape defined by a curved line fulfilling the conditions expressed by the following numerical formulae (1) to (4), and the lens plane of each side portion S of each lens element of emergence 22, the width of this portion S being a quarter of the total lens width L (i.e., L/4), is in the shape defined by a curved line fulfilling the conditions expressed by the following numerical formulae (5) to (8): y=a×b?x?e (?L/4?x?0) . . . (1), y=a×bx?e (0?x?L/4) . . . (2), 3.0×10?4<a<3.8×10?4 . . . (3), 1.
    Type: Grant
    Filed: March 19, 2004
    Date of Patent: May 31, 2005
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventors: Yuko Mori, Katsunori Shintani
  • Patent number: 6833951
    Abstract: The present invention provides an optical faceplate made from fibrous crystals which are transparent, colorless and work as a coherent faceplate. The numeric aperture of a single fiber is within a range of about 0.20 to 0.66. A nonlimiting example of such a fibrous crystal is Ulexite (also known as “TV” rock). In one embodiment the present invention comprises an optical faceplate made of a fibrous crystal in lab-created, artificially grown form. In a further embodiment, an optical faceplate is made of crystals not found in nature, or not found in nature in fibrous form. In one embodiment the present invention provides a seamlessly tiled projection display comprising at least one fibrous crystal faceplate as a pre-screen in combination with a diffused rear projection screen. A faceplate made of fibrous crystals does not have a size limitation. In one embodiment, smaller plates of crystals may be seamlessly tiled into a larger plate, satisfying the need for a large projection screen.
    Type: Grant
    Filed: December 29, 2000
    Date of Patent: December 21, 2004
    Assignee: Honeywell International Inc.
    Inventor: Aleksandra Kolosowsky
  • Patent number: 6717626
    Abstract: A protection panel is provided that enhances the color quality and/or contrast of a rear projection television set. The protection panel has a spectral transmittance that peaks at dominant wavelengths of red, green, and blue light, and that is reduced at wavelengths between red and green light and between green and blue light. The spectral transmittance at the dominant wavelengths is between sixty and eighty percent. Preferably, the spectral transmittance at the wavelengths between red and green light and between green and blue light are at least five percent less than at the dominant wavelengths. In addition, the spectral transmittance at a dominant wavelength of red light is about five percent less than at a dominant wavelength of blue light to reduce blue color saturation.
    Type: Grant
    Filed: May 8, 2000
    Date of Patent: April 6, 2004
    Assignee: Mitsubishi Digital Electronics America, Inc.
    Inventors: Taiji Kondo, Yuzo Nakano, Taketoshi Hibi
  • Patent number: 6296214
    Abstract: A video display screen is held by an elongated holding bracket that has a inwardly extending flange at a distal end of the bracket. The flange fits into a groove extending along the edges of the screen to hold the screen. The bracket is fastened to a support structure. The interior surface of the bracket is advantageously inclined at an angle so the interior surface does not block the light from the projected image, and also has a plurality of grooves to reflect any light incident on the surface away from the screen. In further embodiments, the flange comprises a removable channel section that extends on opposing sides of the screen to hold the screen, with the channel being held against the bracket by a leaf spring.
    Type: Grant
    Filed: April 28, 2000
    Date of Patent: October 2, 2001
    Assignee: ADF, Incorporated
    Inventor: Louis A. Mannick
  • Patent number: 6113041
    Abstract: A video display screen is held by an elongated holding bracket that has a inwardly extending flange at a distal end of the bracket. The flange fits into a groove extending along the edges of the screen to hold the screen. The bracket is fastened to a support structure. The interior surface of the bracket is advantageously inclined at an angle so the interior surface does not block the light from the projected image, and also has a plurality of grooves to reflect any light incident on the surface away from the screen. In further embodiments, the flange comprises a removable channel section that extends on opposing sides of the screen to hold the screen, with the channel being held against the bracket by a leaf spring.
    Type: Grant
    Filed: September 20, 1999
    Date of Patent: September 5, 2000
    Assignee: ADF, Incorporated
    Inventor: Louis A. Mannick
  • Patent number: 6000668
    Abstract: A video display screen is held by an elongated holding bracket that has a inwardly extending flange at a distal end of the bracket. The flange fits into a groove extending along the edges of the screen to hold the screen. The bracket is fastened to a support structure. The interior surface of the bracket is advantageously inclined at an angle so the interior surface does not block the light from the projected image, and also has a plurality of grooves to reflect any light incident on the surface away from the screen. In further embodiments, the flange comprises a removable channel section that extends on opposing sides of the screen to hold the screen, with the channel being held against the bracket by a leaf spring.
    Type: Grant
    Filed: July 29, 1997
    Date of Patent: December 14, 1999
    Assignee: ADF Incorporated
    Inventor: Louis A. Mannick
  • Patent number: 5805211
    Abstract: An electrostatic probe device detects signals displayed on a cathode ray tube in a non-invasive manner. Specifically, the probe device includes a probe that is spaced from a fluorescent screen of a cathode ray tube by a dielectric material and a detection circuit coupled to probe. The detection circuit produces an output signal that corresponds to an input video signal supplied to the cathode ray tube. In a preferred embodiment, the probe is located directly on a face plate of the cathode ray tube, wherein the face plate acts as the dielectric material. Voltage fluctuations detected by the probe are equalized by the detection circuit. The detection circuit may also include amplification and inverter circuits, so that the output of the detection circuit can be supplied to a monitor for viewing. The image displayed on the monitor directly corresponds to the image displayed on the cathode ray tube.
    Type: Grant
    Filed: September 15, 1995
    Date of Patent: September 8, 1998
    Inventor: Ted E. Hartson
  • Patent number: 5796446
    Abstract: A television receiver or video monitor of the back-projection type, in which a projector forms an image which can be observed on a visual display screen by rear illumination after reflection on a deflecting mirror. The projector includes in immediate proximity to the visual display screen and parallel to the latter, a reflection-transmission screen comprising a Fresnel surface, the projector, reflection-transmission screen and deflecting mirror being configured together to form an optical system such that the reflection-transmission screen reflects the rays directly emanating from the projector in the direction of the deflecting mirror and transmits these rays after their reflection on this deflecting mirror. The Fresnel surface includes striations of triangular cross-section, these striations locally forming prisms and capable of reflecting the rays which strike them when the angle of incidence of the rays are greater than a predetermined value and of transmitting the rays in an opposite case.
    Type: Grant
    Filed: March 27, 1996
    Date of Patent: August 18, 1998
    Assignee: Thomson multimedia S.A.
    Inventor: Eric Marcellin-Dibon
  • Patent number: 5742358
    Abstract: A projection type displaying apparatus with a movable built-in screen has an image display, an image projector and a position detector for detecting a position where the built-in screen is installed. When the position detector determines that the built-in screen is in an image projection pass, the focus of the image projector is adjusted on the built-in screen and the image projector projects the image onto the built-in screen. When the position detector determines that the built-in screen is out of the image projection pass, the focus of the image projector is adjusted on an external screen and the image projector automatically projects the image onto the external screen.
    Type: Grant
    Filed: May 3, 1995
    Date of Patent: April 21, 1998
    Assignee: Casio Computer Co., Ltd.
    Inventors: Jun Iijima, Koichi Jinda, Masahiro Ogawa
  • Patent number: 5699131
    Abstract: The present invention provides a screen assembly wherein measures are taken to prevent slack produced in a lenticular lens sheet due to temperature changes and gaps created between a Fresnel lens sheet and the lenticular lens sheet due to temperature changes, thereby enabling the display of images free of inconsistencies in color. The structure of the screen assembly has the lower parts of a lenticular lens sheet and a Fresnel lens sheet comprising a screen fixed together, the upper part of the light radiant side of the lenticular lens sheet fixed to the upper part of a framework, the lower part of the screen, where the Fresnel lens sheet and the lenticular lens sheet are put together not being fixed to the lower part of the framework and a specified clearance created between the lower part of the screen and the lower part of the framework.
    Type: Grant
    Filed: June 25, 1996
    Date of Patent: December 16, 1997
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Satoshi Aoki, Katsuaki Mitani
  • Patent number: 5677071
    Abstract: The present invention is to improve color purity and brightness of a color Braun tube by constructing a fluorescent film for a red fluorescent material as a laminated structure. The present invention relates to a structure of a fluorescent film for a color Braun tube wherein the fluorescent film of the red fluorescent material comprises fluorescent material layers having a laminate structure made of two different compositions of Y.sub.2 O.sub.2 S: Eu and Y.sub.2 O.sub.3 :Eu.
    Type: Grant
    Filed: April 16, 1996
    Date of Patent: October 14, 1997
    Assignee: LG Electronics, Inc.
    Inventor: Seoug Wan Kang
  • Patent number: 5617152
    Abstract: A projector for use with a light source and including a shutter assembly panel having a multiplicity of pixel light valves overlying an array of interspersed shutter pixels each of which transmits only one of a plurality of colors, and a color filter disposed intermediate the light source and the planar shutter and spaced therefrom and having an array of interspersed filter pixels, each of which only transmits only one of a plurality of colors, wherein the array of interspersed filter pixels is in light and color registration with the array of interspersed shutter pixels, such that generally light of a given color impinges on a shutter area of the same color.
    Type: Grant
    Filed: June 20, 1994
    Date of Patent: April 1, 1997
    Assignee: UNIC View Ltd.
    Inventor: Adi Stolov
  • Patent number: 5559564
    Abstract: A cathode ray tube apparatus for a projection TV system which improves the color purity of the luminescence in the cathode ray tube, reduces the chromatic aberration by the projection lens, enables the same type of projection lens to be mounted for all of the green, red and blue CRT apparatuses, and enables manufacturing costs to be slashed by such a common use of components. A light-absorbing agent is incorporated into the panel glass so that the transmittance having the light of wavelengths other than the main wavelength of the spectrum of luminescence of the phosphor of the CRT apparatus, is reduced below the transmittance of the light of the main wavelength. By incorporating this agent into the panel glass of a green CRT apparatus the average value of the transmittance of the light of the wavelength in the range of 500 nm to 560 nm becomes higher than the transmittance of the light of the wavelengths outside this range.
    Type: Grant
    Filed: July 7, 1994
    Date of Patent: September 24, 1996
    Assignee: Sony Corporation
    Inventor: Tsuneharu Nomura
  • Patent number: 5523802
    Abstract: A dual-mode image display apparatus includes a black-and-white image display device and a selective filter. The selective filter is caused to assume a first mode in which it sequentially serves as red, green and blue filters, and a second mode in which it transmits all the color components. Thus, the image display apparatus can selectively perform color display or black-and-white display. The selective filter may include variable optical retarders and may be caused to selectively assume the first mode or the second mode through control over the variable optical retarders. The selective filter may alternatively be moved by a motor between a first position in which the filter is in the path of light from the display device to the viewer, and a second position in which the filter is out of the path of light. A power supply controller is also used to conserve power by turning unneeded parts of a color image processing circuit OFF when the display apparatus is in the second mode.
    Type: Grant
    Filed: January 19, 1994
    Date of Patent: June 4, 1996
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shouichi Sugihara, Masaki Yamakawa
  • Patent number: 5485226
    Abstract: A hood assembly for a display such as a VDU display comprises a partially reflecting mirror made from sheet material having a relatively low light transmittance, in the range 25% to 45%, and most preferably in the range 32.5 to 37.5%.
    Type: Grant
    Filed: March 15, 1994
    Date of Patent: January 16, 1996
    Inventor: John S. Chipperfield
  • Patent number: 5473396
    Abstract: A novel type projection TV has a large size fluorescent screen bearing three kinds of dots or stripes of fluorescent material which emits visible lights of red, green and blue at excitation by UV-rays, which are emitted from UV-emitting CRTs' for red, green and blue pixel of image, respectively; and a mask having UV-light passing apertures or a lens array is disposed on light paths of the UV-rays to improve color purity,
    Type: Grant
    Filed: September 8, 1993
    Date of Patent: December 5, 1995
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Michio Okajima, Takao Tohda
  • Patent number: 5412437
    Abstract: A projection type display device including a CRT with a fluorescent layer and a face glass for projecting an image reflected onto the fluorescent layer through the face glass, a transparent liquid, at least one lens element and onto a screen. The transparent liquid is filled within a space between the face glass of the CRT and the at least one lens element and has a refractive index substantially the same as a refractive index of the face glass of the CRT and the at least one lens element. A light attenuation filter having a transmittance no greater than 0.9 is disposed at a position from the fluorescent layer to the at least one lens element such as between the face glass and the at least one lens element.
    Type: Grant
    Filed: July 6, 1993
    Date of Patent: May 2, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Masanori Ogino, Yoshiaki Iwahara, Syuichi Sakamoto
  • Patent number: 5404181
    Abstract: A monitor filter includes a body having a front cover formed on an upper edge with a recess having a semi-tubular portion at both ends, a rear cover formed on an upper edge with a recess having a semi-tubular portion at both ends, the semi-tubular portion of the rear cover being adapted to the semi-tubular portion of the front cover to form a tubular portion, a spring fitted in the tubular portion, a screen disposed between the front cover and the rear cover; and a fixing frame having two toothed ends each having a protuberance engaged with the spring, the fixing frame being formed with a groove on a top for receiving the body; whereby the monitor filter can be easily assembled and can be turned over through an angle of 210 degrees thereby making it easier to be cleaned.
    Type: Grant
    Filed: August 25, 1993
    Date of Patent: April 4, 1995
    Inventor: Chin-Lung Hung
  • Patent number: 5387948
    Abstract: To prevent light scattering at the edges of CRT's used in projection television, emission of light is prevented beyond a desired region of raster scanning. In one embodiment, portions of the front surfaces of the CRT's outside the desired region are darkened to prevent light emission.
    Type: Grant
    Filed: May 3, 1993
    Date of Patent: February 7, 1995
    Assignee: North American Philips Corporation
    Inventor: Stephen Magocs
  • Patent number: 5353070
    Abstract: In a lens-barrel etc. for holding lenses, a thin film composed of a fluororesin compound having a refractive index lower than that of a material constituting the lens-barrel is formed on an inner surface of the lens-barrel, thereby lowering an amount of the reflective light appeared on the inner surface of the lens-barrel.
    Type: Grant
    Filed: June 4, 1993
    Date of Patent: October 4, 1994
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katsuaki Mitani, Masayuki Takahashi, Syunsuke Kimura
  • Patent number: 5313276
    Abstract: An audiovisual display system for displaying three dimensional images including an image source for projecting an image in a predetermined direction. A stage contained within the audiovisual display system provides a setting for the video image. A transparent screen is disposed between the predetermined direction of the video image source and the stage and is oriented at an angle less than 90.degree. to the line of sight and the predetermined direction so that the viewer views the stage and the video image projected onto the transparent screen so that the image appears to be positioned on the stage.
    Type: Grant
    Filed: May 11, 1992
    Date of Patent: May 17, 1994
    Inventor: Kelly Taaffe
  • Patent number: 5313307
    Abstract: A method for installing a screen to a projection television receiver that uses a transmission-type screen such that the screen can be easily installed to and removed from the projection television receiver when multiple projection television receivers are combined to form a single large-scale multiple display system in which the receivers are stacked vertically and horizontally in an M.times.N rectangular configuration. Screen holding brackets installed in the cabinet body and screen clamping frames are used to secure the screen in place by inserting the screen clamping frames into the slight gap formed between the cabinet body and the screen holding brackets. Even when the screen clamping frames are inserted to the gap and slid to secure the screen, all movement of the clamping frames occurs within the dimensions of the cabinet body, thus making it easy to remove and install the screen even when multiple projection television receivers are combined in a single large-scale display system.
    Type: Grant
    Filed: June 29, 1992
    Date of Patent: May 17, 1994
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katumi Gotou, Satoshi Aoki, Tsuyoshi Shimatani
  • Patent number: 5299017
    Abstract: A screen fixing device of a projection type television system including a projection unit comprises a fixing frame for detachably fixing a screen, the fixing frame being provided with a plurality of through holes each extending laterally of a front opening frame surround a front opening section at which the screen is provided, and a fastening screw penetrating each through hole for fixing the fixing frame to the front opening section of the projection unit. The fixing frame has substantially an L-shaped cross section at least at a portion through which the through hole is formed. Instead of the fixing frame, a fixing block may be used. The fixing device may comprise a plurality of first fixing members for detachably fixing the screen with a space with each other and a plurality of second fixing members for fixing the first fixing members to the front opening section of the projection unit. The first fixing members are formed of a transparent material.
    Type: Grant
    Filed: November 15, 1991
    Date of Patent: March 29, 1994
    Assignee: Pioneer Electronic Corporation
    Inventor: Takashi Furuno