Liquid crystal display apparatus with the application of black level signal for suppressing light leakage

• US 5,105,288 A
• Filed: 10/16/1990
• Issued: 04/14/1992
• Est. Priority Date: 10/18/1989
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Corporation (Panasonic Holdings Corporation)
• Inventors: Nakamura, Akira, Senda, Koji, Yamamoto, Atsuya, Fujii, Eiji, Emoto, Fumiaki
• Primary Examiner(s): Miller, Stanley D.
• Assistant Examiner(s): Duong, Tai V.
• Application Number:
  US07/598,493
• Time in Patent Office: 546 Days
• Field of Search: 350/332, 350/333, 340/784, 340/805, 358/236, 358/237, 358/241
• US Class Current: 345/87
• CPC Class Codes: G09G 2310/0248 Precharge or discharge of column electrodes before or after applying exact column voltages
• 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 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3688 suitable for active matrices only
• CPC Class Codes: H04N 3/127 using liquid crystals

Abstract

A liquid crystal display apparatus in which leakage of light caused by signal lines can be eliminated is disclosed. In the liquid crystal display apparatus, a predetermined potential corresponding to the black level is applied to the video signal lines during a period of time other than the horizontal blanking period, and image signals are transferred to one row of the pixels through the signal lines which the horizontal blanking period.

Claims

1. In a liquid crystal display apparatus comprising:

pixels arranged in rows and columns;

signal lines each for transferring image signals to each column of said pixels; and

image signal means for supplying image signals to said signal lines;

said apparatus further comprises;

potential means for supplying a predetermined potential, said predetermined potential having a level by which the liquid crystal is driven to a black level;

a first connecting means for simultaneously connecting all of said signal lines to said potential means during a first period of each horizontal scanning period, and for simultaneously disconnecting all of said signal lines form said potential means for a second period of said horizontal scanning period, said second period being a horizontal blanking period; and

a second connecting means for simultaneously connecting all of said signal lines to said image signal means within said second period wherein said second period coincides with a selection period of one row of said pixels.

2. A liquid crystal display apparatus according to claim 1, wherein said apparatus further comprises storage means for holding said image signals, said storage means being connected between said image signal mans and said second connecting means.

3. A liquid crystal display apparatus according to claim 1, wherein each of said pixels comprises a storage capacitor for holding an image signal supplied from a corresponding one of said signal lines.

4. In a driving circuit for driving a liquid crystal panel, said panel comprising:

pixels arranged in rows and columns; and

signal lines each for transferring image signals to each column of said pixels,

said driving circuit comprises;

image signal means for supplying image signals to said signal lines;

potential means for supplying a predetermined potential, said predetermined potential having a level by which the liquid crystal is driven in a black level;

a first connecting means for simultaneously connecting all of said signal lines to said potential means during a first period of each horizontal scanning period, and for simultaneously disconnecting all of said signal lines from said potential means for a second period of said horizontal scanning period, said second period being a horizontal blanking period; and

a second connecting means for simultaneously connecting all of said signal lines to said image signal means within said second period wherein said second period coincides with a selection period of one row of said pixels.

5. A liquid crystal display apparatus according to claim 4, wherein said apparatus further comprises storage means for holding said image signals, said storage means being connected between said image signal means and said second connecting means.