Liquid crystal display

• US 7,911,430 B2
• Filed: 01/30/2004
• Issued: 03/22/2011
• Est. Priority Date: 02/03/2003
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Fujine, Toshiyuki
• Primary Examiner(s): Wang; Quan-Zhen
• Assistant Examiner(s): MA, CALVIN
• Application Number:
  US10/544,231
• Publication Number:
  US 20060158410A1
• Time in Patent Office: 2,608 Days
• Field of Search: 345 87-104
• US Class Current: 345/89
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0613 The adjustment depending on the type of the information to be displayed
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A liquid crystal display has an LCD controller, a microcomputer, and a storage section. The LCD controller is capable of setting up an image display period for performing display based on input image data and a black display period for performing display based on black display data, within one field period. The microcomputer switches the mode of the LCD controller between an impulse-drive mode having the image display period and the black display period within the one field period, and a hold drive mode having only the image display period. The storage section stores sets of reference gradation voltage data that are previously specified. A reference gradation voltage, which is generated at a reference gradation voltage generation section and used for driving the liquid crystal display panel, is variable according to the mode. Thus, it is possible to realize the liquid crystal display that can suppress changes in gamma characteristics so as to prevent deterioration of display quality even when the mode is switched.

Claims

1. A liquid crystal display displaying, using a liquid crystal display panel, an image responsive to input image data, comprising:

a driving device that drives the liquid crystal display panel in either an impulse drive mode or a hold drive mode, (i) the impulse drive mode having an image display period for performing display of the input image data and a monochrome display period for performing display of certain previously-specified monochrome display data, each of the display periods being performed within an input image data rewriting period, the input image data and the monochrome display data written sequentially in each of scan lines of the liquid crystal display panel and written in each pixel of the liquid crystal display panel, (ii) the hold drive mode performing display of the input image data for the entire rewriting period, without setting the monochrome display period, the image data written sequentially in each of scan lines of the liquid crystal display panel and written in each pixel of the liquid crystal display panel;

a switching device that switches between the modes for driving the liquid crystal display panel by the driving means; and

a voltage varying device that varies, in accordance with the input image data and according to one of the modes for driving the liquid crystal display panel, a gradation voltage applied to the liquid crystal display panel and corresponding to the image data, so as to prevent changes in gamma characteristics due to differences in response speed of liquid crystal between display gradations, which differences are caused by insertion of the monochrome display data.

2. The liquid crystal display of claim 1, wherein

the voltage varying device varies a reference gradation voltage for driving the liquid crystal display panel.

3. The liquid crystal display of claim 2, further comprising:

a storage section storing sets of reference gradation voltage data previously specified.

4. The liquid crystal display of any one of claims 1, 2, or 3, further comprising:

a temperature detecting device that detects a temperature in the liquid crystal display; and

wherein the voltage varying device varies the level of the gradation voltage to be applied to the liquid crystal display panel, in accordance with the input image data and the detected temperature in the display.

5. The liquid crystal display of any one of claims 1, 2, or 3, wherein

the switching device switches between the modes for driving the liquid crystal display panel in accordance with a user'"'"'s instruction.

6. A liquid crystal display displaying, using a liquid crystal display panel, an image responsive to input image data, comprising:

a driving device that drives the liquid crystal display panel switchably in either an impulse drive mode or a hold drive mode, (i) the impulse drive mode having an image display period for performing display of the input image data and a monochrome display period for performing display of certain previously-specified monochrome display data, each of the display periods being performed within an input image data rewriting period, the input image data and the monochrome display data written sequentially in each of scan lines of the liquid crystal display panel and written in each pixel of the liquid crystal display panel, (ii) the hold drive mode performing display of the input image data for the entire rewriting period, without setting the monochrome display period;

a switching device that switches between the modes for driving the liquid crystal display panel by the driving means; and

a voltage varying device that varies, in accordance with the input image data and according to one of the modes for driving the liquid crystal display panel, a gradation voltage applied to the liquid crystal display panel and corresponding to the image data, so that a relationship between a display gradation of the image and an integral of display transmittance of the image within the input image data rewriting period, in a case where the driving device drives the liquid crystal display panel in the impulse drive mode, is equal to a relationship between the display gradation of the image and the display transmittance of the image in a case where the driving device drives the liquid crystal display panel in the hold drive mode.