Patents by Inventor Machihiko Yamaguchi

Machihiko Yamaguchi 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).

  • Patent number: 7580018
    Abstract: In a liquid crystal display apparatus, a set of write-in voltages are generated corresponding to a horizontal line signal of an input video frame so that they appear at end points of the column lines of a LCD panel. The row lines of the LCD panel are successively selected and the write-in voltages are supplied from the end points of the column lines to the liquid crystal cells of the selected row line for a variable write-in period. In order to compensate for shades-of-gray differences between the top and bottom of the LCD panel, the write-in period is increasingly varied as a function of the geometric distance from the selected row line to the end points of the column lines. The write-in period may be increasingly variable from a nominal value, or from a less-than-nominal value to the nominal value, or a combination of both.
    Type: Grant
    Filed: April 22, 2004
    Date of Patent: August 25, 2009
    Assignee: NEC LCD Technologies, Ltd
    Inventors: Hiroshi Takeda, Machihiko Yamaguchi
  • Patent number: 7126572
    Abstract: A display panel 13 having a plurality of pixels 14 each divided into P (P=3) sub-pixels 15a, 15b and 15c, and a source driver 12 for driving each pixel 14 in accordance with three J (=8)-bit data values corresponding to the sub-pixels 15a, 15b, and 15c, and a signal processing circuit 12 for distributing K(=12)-bit (K>J) input image data as M (M=6) time-shared frame data values and supplying the frame data values to the source driver 12 are arranged. 2K?J (=16) gray levels insufficient due to the difference between the numbers of bits of K-bit input image data and J-bit driving signals of the source driver 12 is realized by combinations of time-shared frame data of (P×M=18) ways performed for the sub-pixels 15a, 15b, and 15c in accordance with the M time-shared frame data values.
    Type: Grant
    Filed: March 26, 2003
    Date of Patent: October 24, 2006
    Assignee: NEC LCD Technologies, Ltd.
    Inventors: Koichi Koga, Noboru Okuzono, Machihiko Yamaguchi
  • Publication number: 20060232534
    Abstract: In a liquid crystal display device where each unit pixel p arranged on a liquid crystal panel 101A is constituted by a plurality of pixels p1, p2, and p3, the pixels p1, p2, and p3 are divided into sub-pixels p11 and p12, sub-pixels p21, and p22, and sub-pixels p31 and p32, respectively. The liquid crystal display device is provided with driver ICs 201 and 202 for driving the sub-pixels p11, p21, and p31, and the sub-pixels p12, p22, and p32 constituting the pixels so that different gradation-brightness value characteristics may be given. Due to this, multi-gradation display can be performed.
    Type: Application
    Filed: May 10, 2006
    Publication date: October 19, 2006
    Inventors: Koichi Koga, Noboru Okuzono, Machihiko Yamaguchi
  • Patent number: 7116297
    Abstract: In a liquid crystal display device where each unit pixel p arranged on a liquid crystal panel 101A is constituted by a plurality of pixels p1, p2, and p3, the pixels p1, p2, and p3 are divided into sub-pixels p11 and p12, sub-pixels p21, and p22, and sub-pixels p31 and p32, respectively. The liquid crystal display device is provided with driver ICs 201 and 202 for driving the sub-pixels p11, p21, and p31, and the sub-pixels p12, p22, and p32 constituting the pixels so that different gradation-brightness value characteristics may be given. Due to this, multi-gradation display can be performed.
    Type: Grant
    Filed: April 14, 2003
    Date of Patent: October 3, 2006
    Assignee: NEC LCD Technologies, Ltd.
    Inventors: Koichi Koga, Noboru Okuzono, Machihiko Yamaguchi
  • Patent number: 6894673
    Abstract: A liquid crystal display control circuit receives a data enable signal DE in synchronization with per-line based display data from a computer, and thereby controls a liquid crystal display. A gate drive signal outputted from a gate driver 23 is generated according to a vertical clock signal VCK in synchronization with a rise of the signal DE. In order to avoid a variation in the period of charging the pixel electrodes which is caused by a delay in the rise timing of the signal DE and a delay in the signal VCK after the last line, a gate enable signal generation circuit 10 is provided in the liquid crystal display control circuit 1, whereby the extended output of the pulse of the gate drive signal caused by the above-mentioned delays is inhibited. This avoids display inhomogeneity caused by a variation in the data enable signal and the like.
    Type: Grant
    Filed: July 10, 2002
    Date of Patent: May 17, 2005
    Assignee: NEC LCD Technologies, Ltd.
    Inventors: Koichi Koga, Noboru Okuzono, Machihiko Yamaguchi
  • Publication number: 20040212577
    Abstract: In a liquid crystal display apparatus, a set of write-in voltages are generated corresponding to a horizontal line signal of an input video frame so that they appear at end points of the column lines of a LCD panel. The row lines of the LCD panel are successively selected and the write-in voltages are supplied from the end points of the column lines to the liquid crystal cells of the selected row line for a variable write-in period. In order to compensate for shades-of-gray differences between the top and bottom of the LCD panel, the write-in period is increasingly varied as a function of the geometric distance from the selected row line to the end points of the column lines. The write-in period may be increasingly variable from a nominal value, or from a less-than-nominal value to the nominal value, or a combination of both.
    Type: Application
    Filed: April 22, 2004
    Publication date: October 28, 2004
    Applicant: NEC LCD TECHNOLOGIES, LTD
    Inventors: Hiroshi Takeda, Machihiko Yamaguchi
  • Patent number: 6788306
    Abstract: A display apparatus is composed of a pseudo gray level data processor generating pseudo gray level data having m bits based on input gray level data having n bits. The pseudo gray level data processor includes a state variable generator generating a state variable data having n−m bits, based on lower n−m bits of the input gray level data, an adder calculating a sum of the lower n−m bits of the input gray level data and the state variable data to output a carry bit representative of carry-over of the sum, and a pseudo gray level data calculator generating the pseudo gray level data based on the input gray level data and the carry bit.
    Type: Grant
    Filed: November 15, 2001
    Date of Patent: September 7, 2004
    Assignee: NEC LCD Technologies, Ltd.
    Inventors: Machihiko Yamaguchi, Youji Hirano
  • Patent number: 6747669
    Abstract: An error diffusing circuit modifies input video data signals representative of the gray levels of 8-bit gradation to output video data signals representative of the gray levels of 6-bit gradation, and an initial value generator produces an initial value for each of the first video data signals on each line of a frame, wherein the initial value generator varies the initial value depending upon the combination of a frame number, a line number and the color so that any pattern is not unintentionally produced on the display panel.
    Type: Grant
    Filed: September 19, 2000
    Date of Patent: June 8, 2004
    Assignee: NEC LCD Technologies, Ltd.
    Inventors: Machihiko Yamaguchi, Koichi Koga
  • Publication number: 20030222840
    Abstract: In a liquid crystal display device where each unit pixel p arranged on a liquid crystal panel 101A is constituted by a plurality of pixels p1, p2, and p3, the pixels p1, p2, and p3 are divided into sub-pixels p11 and p12, sub-pixels p21, and p22, and sub-pixels p31 and p32, respectively. The liquid crystal display device is provided with driver ICs 201 and 202 for driving the sub-pixels p11, p21, and p31, and the sub-pixels p12, p22, and p32 constituting the pixels so that different gradation-brightness value characteristics may be given. Due to this, multi-gradation display can be performed.
    Type: Application
    Filed: April 14, 2003
    Publication date: December 4, 2003
    Applicant: NEC LCD Technologies, Ltd.
    Inventors: Koichi Koga, Noboru Okuzono, Machihiko Yamaguchi
  • Publication number: 20030184569
    Abstract: A display panel 13 having a plurality of pixels 14 each divided into P (P=3) sub-pixels 15a, 15b and 15c, and a source driver 12 for driving each pixel 14 in accordance with three J (=8)-bit data values corresponding to the sub-pixels 15a, 15b, and 15c, and a signal processing circuit 12 for distributing K(=12)-bit (K>J) input image data as M (M=6) time-shared frame data values and supplying the frame data values to the source driver 12 are arranged. 2K−J (=16) gray levels insufficient due to the difference between the numbers of bits of K-bit input image data and J-bit driving signals of the source driver 12 is realized by combinations of time-shared frame data of (P×M=18) ways performed for the sub-pixels 15a, 15b, and 15c in accordance with the M time-shared frame data values.
    Type: Application
    Filed: March 26, 2003
    Publication date: October 2, 2003
    Applicant: NEC Corporation
    Inventors: Koichi Koga, Noboru Okuzono, Machihiko Yamaguchi
  • Publication number: 20030011557
    Abstract: A liquid crystal display control circuit receives a data enable signal DE in synchronization with per-line based display data from a computer, and thereby controls a liquid crystal display. A gate drive signal outputted from a gate driver 23 is generated according to a vertical clock signal VCK in synchronization with a rise of the signal DE. In order to avoid a variation in the period of charging the pixel electrodes which is caused by a delay in the rise timing of the signal DE and a delay in the signal VCK after the last line, a gate enable signal generation circuit 10 is provided in the liquid crystal display control circuit 1, whereby the extended output of the pulse of the gate drive signal caused by the above-mentioned delays is inhibited. This avoids display inhomogeneity caused by a variation in the data enable signal and the like.
    Type: Application
    Filed: July 10, 2002
    Publication date: January 16, 2003
    Applicant: NEC Corporation
    Inventors: Koichi Koga, Noboru Okuzono, Machihiko Yamaguchi
  • Publication number: 20020105491
    Abstract: A display apparatus is composed of a pseudo gray level data processor generating pseudo gray level data having m bits based on input gray level data having n bits. The pseudo gray level data processor includes a state variable generator generating a state variable data having n−m bits, based on lower n−m bits of the input gray level data, an adder calculating a sum of the lower n−m bits of the input gray level data and the state variable data to output a carry bit representative of carry-over of the sum, and a pseudo gray level data calculator generating the pseudo gray level data based on the input gray level data and the carry bit.
    Type: Application
    Filed: November 15, 2001
    Publication date: August 8, 2002
    Applicant: NEC CORPORATION
    Inventors: Machihiko Yamaguchi, Youji Hirano