Image display device and method for displaying multi-gray scale display

• US 7,206,005 B2
• Filed: 02/23/2001
• Issued: 04/17/2007
• Est. Priority Date: 02/25/2000
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Yamashita, Hiroshi, Yamauchi, Kazushi, Kusafuka, Kaoru
• Primary Examiner(s): Shalwala; Bipin
• Assistant Examiner(s): Lewis; David L.
• Application Number:
  US09/791,963
• Publication Number:
  US 20010026258A1
• Time in Patent Office: 2,244 Days
• Field of Search: 345694-698, 345/89, 345/88, 345/95, 345/90, 345/85, 345/149, 345/55, 345/690, 345/613, 345/614, 345/152, 345211-212, 345/99, 349108-110, 349/106, 349/173, 349/85, 349/105, 430/5
• US Class Current: 345/695
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/2092 Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 5/028 Circuits for converting colour display signals into monochrome display signals

Abstract

An image display device for multi-gray scale display includes a first pixel for transmitting an achromatic color light therethrough with a first transmittance and a second pixel for transmitting the achromatic color light therethrough with a second transmittance different from the first transmittance of the first pixel. In this case, for video data to be entered, gray scale display allowed with the first transmittance of the first pixel and gray scale display allowed with the second transmittance of the second pixel are combined, to display the gray scale of the video data.

Claims

1. An image display device for multi-gray scale display, comprising:

a first pixel for transmitting an achromatic color light therethrough with a first transmittance; and

a second pixel for transmitting the achromatic color light therethrough having a second transmittance being different from the first transmittance of the first pixel,

wherein gray scale display allowed with the first transmittance of the first pixel and gray scale display allowed with the second transmittance of the second pixel are combined for video data to be entered, to display gray scale of the video data, and

wherein transmittances of the first and second pixels are set to be different from each other by changing sizes of apertures thereof for light transmission.

2. An image display device for multigray scale display, comprising:

a first pixel for transmitting an achromatic color light therethrough with a first transmittance;

a second pixel for transmitting the achromatic color light therethrough having a second transmittance being different from the first transmittance of the first pixel;

wherein gray scale display allowed with the first transmittance of the first pixel and gray scale display allowed with the second transmittance of the second pixel are combined for video data to be entered, to display gray scale of the video data; and

wherein transmittances of the first and second pixels are set to be different from each other by coating achromatic color resists.

3. A liquid crystal display device for displaying gray scale of one pixel image by a plurality of subpixels, comprising:

a first subpixel for performing predetermined gray scale display with a first light quantity;

a second subpixel for performing gray scale display with a second light quantity having a lower/upper limit different from that of the first light quantity of the first subpixel; and

a control unit for performing control to display gray scale of a pixel image of entered image data by combining the first and second subpixels, the control unit configured to provide different maximum drive voltages to the first and second subpixels.

4. The liquid crystal display device according to claim 3, wherein the lower/upper limit of the second light quantity of the second subpixel is set by changing a voltage value applied thereto, and gray scale display is performed by controlling a voltage value such that the second light quantity is divided into predetermined quantities.

5. An image displaying method for outputting entered multigray scale monochrome image data to a liquid crystal cell, comprising the steps of:

storing an output relation of gray scale display made for an entered pixel value by combining gray scale of a first subpixel having a first maximum output light quantity and gray scale of a second subpixel having a second maximum output light quantity; and

deciding output values of the first and second subpixels for one pixel value in the entered monochrome image data based on the stored output relation, and outputting the values to the liquid crystal cell.

6. The image displaying method according to claim 5, wherein the method further comprises the step of changing light transmittance for the first maximum output light quantity, whereby a second maximum output light quantity of the second subpixel is obtained.

7. The image displaying method according to claim 5, wherein the method further comprises the steps of providing the second subpixel with an aperture narrowed by a black matrix provided in the liquid crystal cell, and setting the second subpaxel at the second maximum output light quantity.

8. An imagedisplaying method for displaying gray scale of one pixel image by a plurality of subpixels, comprising the steps of:

preparing a subpixel having a lower and an upper limit light quantity made different among the plurality of subpixels to allow predetermined gray scale display, the subpixel having a different aperture size than the plurality of subpixels; and

performing multi-gray scale display by combining the subpixel having the lower and upper limit light quantities made different with other subpixels.

9. The image displaying method according to claim 8, wherein the method further comprises the step of changing a maximum voltage value for the lower and upper limit light quantities for the plurality of subpixels.

10. An image display device for multi-gray scale display, comprising:

a first pixel for transmitting an achromatic color light therethrough with a first transmittance;

a first aperture for light transmittance of the first pixel;

a second pixel for transmitting the achromatic color light therethrough having a second transmittance being different from the first transmittance of the first pixel; and

a second aperture for light transmittance of the second pixel, wherein the size of the second aperture is different than the size of the first aperture.

11. An image display device for multigray scale display, comprising:

a first pixel for transmitting an achromatic color light therethrough with a first transmittance;

a first achromatic color resist for light transmittance of the first pixel;

a second pixel for transmitting the achromatic color light therethrough having a second transmittance being different from the first transmittance of the first pixel; and

a second achromatic color resist for light transmittance of the second pixel, wherein the transmittance the second achromatic color resist is different than the transmittance of the first achromatic color resist.