Liquid crystal display having adjustable effective voltage value for display

• US 6,362,803 B1
• Filed: 03/12/1998
• Issued: 03/26/2002
• Est. Priority Date: 03/12/1997
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Tomomura, Yoshinobu, Nakaue, Tahei, Takahashi, Nobuaki
• Primary Examiner(s): Nguyen, Chanh
• Assistant Examiner(s): Alphonse, Fritz
• Application Number:
  US09/041,256
• Time in Patent Office: 1,475 Days
• Field of Search: 345/94, 345/89, 345/95, 345/101, 345/90, 345/97, 345/1, 345/2, 357/56
• US Class Current: 345/94
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3622 using a passive matrix G09G3/3674 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3681 suitable for passive matrices only
• CPC Class Codes: G09G 3/3692 suitable for passive matrices only

Abstract

A liquid crystal display includes a liquid crystal display panel including a signal side substrate having an arrangement of a plurality of signal electrodes, a scanning side substrate positioned opposite to the signal side substrate and having an arrangement of a plurality of scanning electrodes crossing the plurality of signal electrodes, a liquid crystal layer positioned between the signal side substrate and the scanning side substrate, and a signal side driving circuit and a scanning side driving circuit for applying driving pulse voltage signals for displaying data to the plurality of signal electrodes and the plurality of scanning electrodes, respectively for driving these electrodes. When data is displayed, at least one of the driving pulse voltage signals is provided with a correction pulse voltage signal such that the effective voltage value of each part of the liquid crystal display panel attains an optimum level. The correction is achieved by adjusting the pulse width of the correction pulse voltage signal. As a result, unevenness in display quality may be improved without crosstalk.

Claims

1. A liquid crystal display comprising a liquid crystal display panel including a signal side substrate having an arrangement of a plurality of signal electrodes, a scanning side substrate disposed opposite to said signal side substrate and having an arrangement of a plurality of scanning electrodes disposed in crossing relationship to said plurality of signal electrodes, and a liquid crystal layer positioned between said signal side substrate and said scanning side substrate so as thereby to define a matrix type array of pixels, and a signal side driving circuit and a scanning side driving circuit for applying driving pulse voltage signals to said plurality of signal electrodes and said plurality of scanning electrodes, respectively, for driving the respective electrodes, and for displaying data on the pixels of said matrix type array, wherein:

(i) at the time of displaying data, during a selecting period in which selective scanning is performed for each of said plurality of scanning electrodes, said driving pulse voltage signals applied to said plurality of signal electrodes and/or to said plurality of scanning electrodes is corrected respectively by adding thereto a correction pulse voltage signal having a pulse width subject to an appropriate adjustment for each of said plurality of scanning electrodes and/or for each of said plurality of signal electrodes so as to optimize a level of effective voltage value applied to each pixel of said liquid crystal display panel;

(ii) said driving pulse voltage signals include a data voltage signal applied to said plurality of signal electrodes for displaying data, and a selecting voltage signal applied to said plurality of scanning electrodes during said selecting periods therefor for selecting and scanning said plurality of scanning electrodes when data is displayed; and

(iii) said correction pulse voltage signal includes a non-selecting voltage signal applied in non-selecting periods to said plurality of scanning electrodes and having a level different from said selecting voltage signal, and said non-selecting voltage signal is applied to said plurality of scanning electrodes for a first prescribed time period in said selecting periods for said scanning electrodes and said first prescribed time period is subjected to said adjustment for each of said plurality of said scanning electrodes.

2. A liquid crystal display comprising a liquid crystal display panel including a signal side substrate having an arrangement of a plurality of signal electrodes, a scanning side substrate disposed opposite to said signal side substrate and having an arrangement of a plurality of scanning electrodes disposed in crossing relationship to said plurality of signal electrodes, and a liquid crystal layer positioned between said signal side substrate and said scanning side substrate so as thereby to define a matrix type array of pixels, and a signal side driving circuit and a scanning side driving circuit for applying driving pulse voltage signals to said plurality of signal electrodes and said plurality of scanning electrodes, respectively, for driving the respective electrodes, and for displaying data on the pixels of said matrix type array, wherein:

(i) at the time of displaying data, during a selecting period in which selective scanning is performed for each of said plurality of scanning electrodes, said driving pulse voltage signals applied to said plurality of signal electrodes and/or to said plurality of scanning electrodes is corrected respectively by adding thereto a correction pulse voltage signal having a pulse width subject to an appropriate adjustment for each of said plurality of scanning electrodes and/or for each of said plurality of signal electrodes so as to optimize a level of effective voltage value applied to each pixel of said liquid crystal display panel;

(ii) said driving pulse voltage signals include a data voltage signal applied to said plurality of signal electrodes for displaying data, and a selecting voltage signal applied to said plurality of scanning electrodes during said selecting periods therefor for selecting and scanning said plurality of scanning electrodes when data is displayed; and

(iii) said correction pulse voltage signal includes an intermediate voltage signal applied to said plurality of signal electrodes when data is not displayed, said intermediate voltage signal is applied to said plurality of signal electrodes for a second prescribed time period if said data voltage signal is applied, and said second prescribed time period is subjected to said adjustment for each of said plurality of signal electrodes.