Patents by Inventor Katsuhiko Kumagawa

Katsuhiko Kumagawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20040100602
    Abstract: A liquid crystal screen display is disclosed which is capable of restraining occurrence of display unevenness. In the display of the invention, a conductive member to which a negative voltage is applied is placed between a substrate and an alignment layer so as to be in partial contact with the alignment layer. Uneven ion distribution attributable to ion generation within broken or pin hole parts of an overcoat film is restrained, for instance, by exposing gate signal lines etc. to the alignment layer so that ions are intentionally generated in the regions of the liquid crystal layer corresponding to the exposed regions.
    Type: Application
    Filed: November 24, 2003
    Publication date: May 27, 2004
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventors: Ichiro Sato, Katsuhiko Kumagawa, Kazuo Inoue, Kazuhiro Nishiyama
  • Patent number: 6717628
    Abstract: One of a pair of substrates with liquid crystals sandwiched therebetween includes a plurality of pixels each of which is provided with a scanning electrode, an image signal electrode, a switching element provided at an intersection of the scanning electrode and the image signal electrode, a pixel electrode connected to the image signal electrode via the switching element, a counter electrode, and a busbar electrically connected to the counter electrode. A portion of the pixel electrode is overlapped with the busbar so as to make up a storage capacitance. A shape of the pixel electrode is altered for each pixel so that a value of the storage capacitance becomes smaller from a feeding side to a termination side. The portion of the pixel electrode overlapped with the busbar so as to make up the storage capacitance is located within the busbar in a plan view of the device.
    Type: Grant
    Filed: October 23, 2002
    Date of Patent: April 6, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katsuhiko Kumagawa, Masanori Kimura, Tetsuo Fukami
  • Patent number: 6697141
    Abstract: A liquid crystal display comprises an array substrate in which a common electrode, a pixel electrode, a scanning signal line, a video signal line and a semiconductor switching element are provided, an opposed substrate, and a liquid crystal layer interposed between the array substrate and opposed substrate. The line width of at least either the common electrode or the pixel electrode is larger than the distance between the common electrode and the pixel electrode. The film thickness of at least one of the common electrode and the pixel electrode is larger than the thickness of at least either the scanning signal line or the video signal line. As a result, an in-plane electric field liquid crystal display having a wide viewing angle, high-speed response, and high image quality such as high luminance is provided.
    Type: Grant
    Filed: June 4, 2002
    Date of Patent: February 24, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroyuki Yamakita, Katsuhiko Kumagawa, Kazuo Inoue, Akinori Shiota, Ichiro Sato, Hiroshi Satani, Masanori Kimura, Satoshi Asada
  • Patent number: 6633272
    Abstract: A compact and inexpensive LCD is provided by improving a drive method for compensating a crosstalk using a compensating pulse added to a signal voltage so that a drive IC and a periphery of the LCD panel are reduced in size. Only one of positive and negative compensating pulses is added in accordance with a predetermined period. Alternatively, the two compensating pulses are added at different times from each other in one horizontal scanning period. The compensating pulse preferably has a waveform including low frequency components. A width or a height of the compensating pulse varies in accordance with a location of the signal electrode, display pattern or other factors.
    Type: Grant
    Filed: March 1, 2000
    Date of Patent: October 14, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katsuhiko Kumagawa, Akira Kawaji, Masahito Matsunami, Takeshi Okuno, Tohru Suyama
  • Patent number: 6597337
    Abstract: A compact and inexpensive LCD is provided by improving a drive method for compensating a crosstalk using a compensating pulse added to a signal voltage so that a drive IC and a periphery of the LCD panel are reduced in size. Only one of positive and negative compensating pulses is added in accordance with a predetermined period. Alternatively, the two compensating pulses are added at different times from each other in one horizontal scanning period. The compensating pulse preferably has a waveform including low frequency components. A width or a height of the compensating pulse varies in accordance with a location of the signal electrode, display pattern or other factors.
    Type: Grant
    Filed: October 11, 2000
    Date of Patent: July 22, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katsuhiko Kumagawa, Akira Kawaji, Masahito Matsunami, Takeshi Okuno, Tohru Suyama
  • Publication number: 20030122767
    Abstract: A liquid crystal display of the present invention is adapted to perform initialization by inputting voltages with different polarities to two pixel electrodes (23á, 23â) adjacent in front and back direction. It is preferable that in the two pixel electrodes (23á, 23â) adjacent in front and back direction, the pixel electrode (23á) located on back side is provided with a first protrusion (232á) at a front side edge (231á) thereof and in the two pixel electrodes adjacent in front and back direction, the pixel electrode (23â) located on front side is provided with a second protrusion (234â) on a back side edge (233â) thereof.
    Type: Application
    Filed: October 9, 2002
    Publication date: July 3, 2003
    Inventors: Kenji Nakao, Daiichi Suzuki, Yoshinori Kobayashi, Katsuyuki Arimoto, Katsuhiko Kumagawa, Ichiro Sato, Keisuke Tsuda, Hirofumi Wakemoto, Hiroyuki Yamakita, Masanori Kimura, Yoshinori Tanaka, Akinori Shiota
  • Publication number: 20030117534
    Abstract: One of a pair of substrates with liquid crystals sandwiched therebetween includes a plurality of pixels each of which is provided with a scanning electrode, an image signal electrode, a switching element provided at an intersection of the scanning electrode and the image signal electrode, a pixel electrode connected to the image signal electrode via the switching element, a counter electrode, and a busbar electrically connected to the counter electrode. A portion of the pixel electrode is overlapped with the busbar so as to make up a storage capacitance. A shape of the pixel electrode is altered for each pixel so that a value of the storage capacitance becomes smaller from a feeding side to a termination side. The portion of the pixel electrode overlapped with the busbar so as to make up the storage capacitance is located within the busbar in a plan view of the device.
    Type: Application
    Filed: October 23, 2002
    Publication date: June 26, 2003
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katsuhiko Kumagawa, Masanori Kimura, Tetsuo Fukami
  • Patent number: 6583840
    Abstract: A liquid crystal display element comprising a liquid crystal panel which comprises a pair of substrates and liquid crystal material sealed between the pair of substrates and in which pixel electrode parts of pixel electrodes and common electrode parts of common electrodes are alternately formed on a plane of one of the pair of substrates to change alignment of liquid crystal molecules by generating a horizontal (X) electric field in the plane, wherein at least one of the pixel electrode parts and the common electrode parts has a tapered section with respect to a horizontal (X) electric field direction and are transparent. The horizontal (X) electric field causes improved display characteristics, aperture ratio and response speed.
    Type: Grant
    Filed: May 26, 2000
    Date of Patent: June 24, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kazuo Inoue, Hiroyuki Yamakita, Katsuhiko Kumagawa, Masanori Kimura, Akinori Shiota
  • Publication number: 20030090609
    Abstract: A liquid crystal display device comprises a pair of substrates (1, 2) each having an electrode (13, 5), a liquid crystal layer held between the pair of substrates (1, 2) in which at least two kinds of projections (20, 21) having different projection heights are formed on one of the pair of substrates (1, 2) using the same material. These projections (20, 21) are obtained by the process comprising the steps, i.e., a resin film formation step of forming a projection resin film on the surface of one of the pair of substrates (1, 2) using photosensitive resin, and a projection formation step of simultaneously forming at least two types of projections (20, 21) having different projection heights on the substrate (2) using a photomask having variable transmittances and conducting exposure and development in such a manner that resulting thickness of the projection resin film can be varied.
    Type: Application
    Filed: October 11, 2002
    Publication date: May 15, 2003
    Inventors: Kazuo Inoue, Katsuhiko Kumagawa, Akio Takimoto
  • Publication number: 20030081164
    Abstract: A liquid crystal screen display is disclosed which is capable of restraining occurrence of display unevenness. In the display of the invention, a conductive member to which a negative voltage is applied is placed between a substrate and an alignment layer so as to be in partial contact with the alignment layer. Uneven ion distribution attributable to ion generation within broken or pin hole parts of an overcoat film is restrained, for instance, by exposing gate signal lines etc. to the alignment layer so that ions are intentionally generated in the regions of the liquid crystal layer corresponding to the exposed regions.
    Type: Application
    Filed: May 15, 2002
    Publication date: May 1, 2003
    Inventors: Ichiro Sato, Katsuhiko Kumagawa, Kazuo Inoue, Kazuhiro Nishiyama
  • Publication number: 20030063074
    Abstract: The present invention provides a display apparatus that can reduce a voltage irregularity and a brightness irregularity accompanied by making an enlarged and a high resolution type display apparatus.
    Type: Application
    Filed: December 21, 2001
    Publication date: April 3, 2003
    Inventors: Katsuhiko Kumagawa, Masanori Kimura, Tetsuo Fukami, Akio Takimoto, Yukio Tamaka, Kazunori Komori
  • Patent number: 6525798
    Abstract: A liquid crystal display unit including a plurality of pixels each including a plurality of common electrodes, a plurality of pixel electrodes, and a semiconductor switching element, a plurality of scanning signal lines, a plurality of video signal lines for outputting signals to the pixel electrodes. The display further includes an array substrate having the pixels, the scanning signal lines, and the video signal lines arranged on a surface thereof, a counter substrate arranged opposite the array substrate, and a liquid crystal layer sandwiched between the array substrate and the counter substrate, wherein each of the pixels includes a plurality of electrode pairs, each electrode pair including one of the common electrodes and an adjacent one of the pixel electrodes, and at least one of the electrode pairs differs from other electrode pairs in a thickness of its common electrode or a thickness of its pixel electrode.
    Type: Grant
    Filed: October 20, 2000
    Date of Patent: February 25, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroyuki Yamakita, Katsuhiko Kumagawa, Akinori Shiota, Ichiro Sato, Akio Takimoto
  • Patent number: 6522318
    Abstract: A compact and inexpensive LCD is provided by improving a drive method for compensating a crosstalk using a compensating pulse added to a signal voltage so that a drive IC and a periphery of the LCD panel are reduced in size. Only one of positive and negative compensating pulses is added in accordance with a predetermined period. Alternatively, the two compensating pulses are added at different times from each other in one horizontal scanning period. The compensating pulse preferably has a waveform including low frequency components. A width or a height of the compensating pulse varies in accordance with a location of the signal electrode, display pattern or other factors.
    Type: Grant
    Filed: March 1, 2000
    Date of Patent: February 18, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katsuhiko Kumagawa, Akira Kawaji, Masahito Matsunami, Takeshi Okuno, Tohru Suyama
  • Publication number: 20030011555
    Abstract: A method of driving a liquid crystal display and the liquid crystal display of the present invention are such that in a liquid crystal display in which video signals are written onto a plurality of pixels frame by frame (Tf), voltages corresponding to the video signals are held in the pixels, and a modulation degree of the liquid crystal layer in an alignment state for display is controlled in accordance with the held voltages, thereby displaying an image, a backward-transition-prevention voltage &Dgr;V for preventing backward transition of a liquid crystal layer is temporalily superposed on the voltages (Vd1-Vdn) corresponding to the video signals in a hold period (Th) of the voltages (Vd1-Vdn) corresponding to the video signals.
    Type: Application
    Filed: August 22, 2002
    Publication date: January 16, 2003
    Inventors: Tetsuo Fukami, Katsuhiko Kumagawa, Kenji Nakao
  • Publication number: 20020196220
    Abstract: Disclosed is a liquid crystal display capable of ensuring brightness necessary for achieving satisfactory display by increasing ratio of light-emitting time to one frame period. A liquid crystal display is adapted to have a period (non-video signal write period) required for writing non-video signals different from video signals onto all the pixels before a video signal write period. In the non-video signal write period, the non-video signals are written onto the respective pixels, thereby starting response of the liquid crystal before the start of the video signal write period. In the non-video signal write period, a backlight is turned off, and thereby image degradation is prevented even when the non-video signals are written onto the respective pixels.
    Type: Application
    Filed: March 28, 2002
    Publication date: December 26, 2002
    Inventors: Ichiro Sato, Katsuhiko Kumagawa, Hiroyuki Yamakita, Kazunori Komori
  • Publication number: 20020176043
    Abstract: A liquid crystal display panel of the invention is such that, in a pixel region defined by a region of the array substrate surrounded by a pair of image signal lines and a pair of scanning signal lines, of a line-shaped pixel electrode and a common electrode, the electrode that is disposed adjacent to and parallel to a signal line is made of an opaque conductor and at least one of the other electrodes is made of a transparent conductor. Adverse effects of the electric field formed between a signal line and an adjacent electrode thereto are suppressed and a sufficient aperture ratio is ensured by using a transparent conductor for the electrode contributing good display.
    Type: Application
    Filed: December 5, 2001
    Publication date: November 28, 2002
    Inventors: Tetsuo Fukami, Katsuhiko Kumagawa, Hiroyuki Yamakita, Masanori Kimura, Michiko Okafuji, Satoshi Asada
  • Publication number: 20020171779
    Abstract: The liquid crystal display device having an array substrate (10) provided with a pixel electrode (3) disposed in a region defined by two adjacent gate wirings (1) and two adjacent source wirings (2), a switching element (5) for switching a voltage applied to the pixel electrode (3) from the source wiring (2) based on a signal volume fed from the gate wiring (1), a common wiring (8) formed between the two adjacent gate wirings (1), a common electrode (4) being electrically connected to the common wiring (8) and generating an electric field between the common electrode (4) and the pixel electrode (3) for driving the liquid crystal, and a storage capacity electrode (20a) electrically connected to the common wiring (8), wherein the common wiring (8) and the storage capacity electrode (20a) are layered so as to hold at least some part of the pixel electrode (3) in between through insulating layers (6a, 6b).
    Type: Application
    Filed: May 28, 2002
    Publication date: November 21, 2002
    Inventors: Masanori Kimura, Katsuhiko Kumagawa, Tetsuo Fukami, Hiroyuki Yamakita, Satoshi Asada
  • Publication number: 20020158997
    Abstract: In a liquid crystal panel in which pseudo dot inversion driving is performed, the occurrence of flicker or vertical and horizontal strings is prevented by preventing an alignment shift between individual layers during the fabrication of a TFT array from producing a difference between the respective abilities of thin-film TFTs to charge adjacent pixels (61, 62). For this purpose, the liquid crystal display panel is constructed such that two TFTs which are enclosed by two adjacent image signal lines (21, 22) and scan signal lines (3) and adjacent to each other along the signal lines (21, 22) have respective source electrodes (71, 72) adjacent to the different image signal lines (21, 22). The source electrodes (71, 72) and drain electrodes (81, 82) of the two TFTs connected to the adjacent pixels (61, 62) are alternately arranged such that variations caused by the alignment shift in the sizes and areas of overlapping portions between the individual layers of the TFTs are equal or the same.
    Type: Application
    Filed: August 24, 2001
    Publication date: October 31, 2002
    Inventors: Tetsuo Fukami, Katsuhiko Kumagawa, Masanori Kimura, Satoshi Asada, Yoneharu Takubo
  • Publication number: 20020154262
    Abstract: A liquid crystal display comprises an array substrate in which a common electrode, a pixel electrode, a scanning signal line, a video signal line and a semiconductor switching element are provided, an opposed substrate, and a liquid crystal layer interposed between the array substrate and opposed substrate. The line width of at least either the common electrode or the pixel electrode is larger than the distance between the common electrode and the pixel electrode. The film thickness of at least either the scanning signal line or the video signal line. As a result, an in-plane electric field liquid crystal display having a wide viewing angle, high-speed response, and high image quality such as high luminance is provided.
    Type: Application
    Filed: June 4, 2002
    Publication date: October 24, 2002
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventors: Hiroyuki Yamakita, Katsuhiko Kumagawa, Kazuo Inoue, Akinori Shiota, Ichiro Sato, Hiroshi Satani, Masanori Kimura, Satoshi Asada
  • Publication number: 20020154079
    Abstract: A liquid crystal display device, wherein liquid crystal is driven by an electric field that is parallel to a substrate, includes a plurality of gate lines (Xm−1), (Xm) and a plurality of data lines (Yn−1), (Yn) provided such that the data lines intersect with the plurality of gate lines, switching elements (13) connected to the gates lines (Xm−1) and the data lines (Yn−1), pixel electrodes (11) connected to the data lines (Yn−1) via the switching elements (13), and opposing electrodes (12) forming pairs with the pixel electrodes (11), wherein a plurality of storage capacities (14a), (14b) for maintaining a charge of the pixel electrodes (11) are provided in a distributed arrangement associated with points where the plurality of gate lines (Xm−1), (Xm) and the plurality of data lines (Yn−1), (Yn) intersect.
    Type: Application
    Filed: October 12, 2001
    Publication date: October 24, 2002
    Inventors: Akinori Shiota, Hiroyuki Yamakita, Katsuhiko Kumagawa, Sadayoshi Hotta, Yoneharu Takubo