Liquid crystal display device

• US 7,301,523 B2
• Filed: 06/01/2004
• Issued: 11/27/2007
• Est. Priority Date: 06/04/2003
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Kamei, Tatsuo
• Primary Examiner(s): Tran; Henry N
• Application Number:
  US10/856,934
• Publication Number:
  US 20040246435A1
• Time in Patent Office: 1,274 Days
• Field of Search: 345/102, 345/207, 345/690, 349/58, 349/61, 349/62, 362/29, 362/30, 362543-545, 362/611, 362/612, 359/62, 359/83, 359/86, 714/742
• US Class Current: 345/102
• CPC Class Codes: G02F 1/13318 Circuits comprising a photodetector
• CPC Class Codes: G02F 1/133388 with constructional differences between the display region and the peripheral region
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources

Abstract

In a liquid crystal display device including a liquid crystal display panel and a backlight, the present invention provides a detection-use pixel having the same constitution as respective pixels constituting a liquid crystal display part in the liquid crystal display panel and being formed on a region other than the liquid crystal display part, a light detector detecting light from the backlight through the detection-use pixel, and a controller adjusting the intensity of the light from the backlight in response to a signal from the light detector to adjust the change of the characteristics and chromaticity in the liquid crystal display panel properly.

Claims

1. A liquid crystal display device including a liquid crystal display panel, a back light, and a controller wherein the liquid crystal display panel includes

a test pixel for detection which has the same constitution as respective pixels constituting a liquid crystal display part of the liquid crystal display panel,

the test pixel being formed on a region other than the liquid crystal display part, and

a mirror arranged on an observation-side surface of the liquid crystal display panel, the mirror reflecting light from the backlight through the test pixel, and

wherein the controller adjusts the intensity of the light from the backlight in response to a signal from a light detector.

2. A liquid crystal display device according to claim 1, wherein

a frame having a display window which exposes the liquid crystal display part of the liquid crystal display panel is arranged on the observation-side surface of the liquid crystal display panel, and

the use test pixel is covered with the frame.

3. A liquid crystal display device according to claim 1, wherein

a polarizing element is formed between the test pixel and the light detector.

4. A liquid crystal display device according to claim 1, wherein

the light detector is arranged on a surface of the liquid crystal display panel opposite to the observation-side surface, and

the test pixel is formed between the mirror and the light detector.

5. A liquid crystal display device according to claim 1, wherein the test pixel is a dummy pixel which is formed on peripheries of the respective pixels which constitute the liquid crystal display part.

6. A liquid crystal display device including a liquid crystal display panel for color display, a back light which has a red light source, a green light source, a blue light source, and a controller, wherein

the liquid crystal display panel includes

test pixels comprising test red pixel for detection, a test green pixel for detection and a test blue pixel for detection which have the same constitution as respective pixels constituting a liquid crystal display part of the liquid crystal display panel are formed on a region other than the liquid crystal display part,

a mirror arranged on an observation-side surface of the liquid crystal display panel, the mirror reflecting light from the backlight through the test red pixel, the test green pixel, and the test blue pixel, and

a light detector which detects light from the mirror,

wherein the controller adjusts the intensities of the red light source, the green light source and the blue light source of the backlight in response to signals from the light detectors.

7. A liquid crystal display device according to claim 6, wherein

a frame having a display window which exposes the liquid crystal display part of the liquid crystal display panel is arranged on the observation-side surface of the liquid crystal display panel, and

the test pixels are covered with the frame.

8. A liquid crystal display device according to claim 6, wherein

a polarizing element is formed between the test pixels and the light detector.

9. A liquid crystal display device according to claim 6, wherein

the light detector is arranged on a surface of the liquid crystal display panel opposite to the observation-side surface, and

the test red pixel, the test green pixel, and the test blue pixel are formed between the mirror and the light detector.

10. A liquid crystal display device according to claim 6, wherein the test red pixel, the test green pixel, and the test blue pixel are dummy pixels which are formed on peripheries of the respective pixels which constitute the liquid crystal display part.