Liquid crystal display device

• US 20040246435A1
• Filed: 06/01/2004
• Published: 12/09/2004
• 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
• Granted Patent: US 7,301,523 B2
• Time in Patent Office: Days
• US Class Current: 349/199
• 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 and a back light, wherein a detection-use pixel which has the same constitution as respective pixels constituting a liquid crystal display part of the liquid crystal display panel is formed on a region other than the liquid crystal display part, and

the liquid crystal display device further includes a light detector which detects light from the backlight through the detection-use pixel and a controller which adjusts the intensity of the light from the backlight in response to a signal from the light detector.

2. A liquid crystal display device according to claim 1, wherein a frame having a display window which exposes a liquid crystal display part of the liquid crystal display panel is arranged on an observation-side surface of the liquid crystal display panel, and the detection-use pixel is covered with the frame.

3. A liquid crystal display device according to claim 1, wherein the light detector is arranged on the observation-side surface of the liquid crystal display panel.

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, at the same time, a mirror is arranged on the observation-side surface of the liquid crystal display panel in a state that the mirror and the light detector sandwich the detection-use pixel.

5. A liquid crystal display device according to claim 1, wherein the detection-use pixels are formed by making use of dummy pixels which are 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 and a back light, the back light including a red light source, a green light source and a blue light source, wherein a detection-use red pixel, a detection-use green pixel and a detection-use blue pixel 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, and

the liquid crystal display device further includes a red light detector, a green light detector and a blue light detector which detect light from the backlight through the detection-use red pixel, the detection-use green pixel, the detection-use blue pixel and a controller which 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 a liquid crystal display part of the liquid crystal display panel is arranged on an observation-side surface of the liquid crystal display panel, and the detection-use pixel is covered with the frame.

8. A liquid crystal display device according to claim 6, wherein the light detector is arranged on the observation-side surface of the liquid crystal display panel.

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, at the same time, a mirror is arranged on the observation-side surface of the liquid crystal display panel in a state that the mirror and the light detector sandwich the detection-use pixel.

10. A liquid crystal display device according to claim 6, wherein the detection-use pixels are formed by making use of dummy pixels which are formed on peripheries of the respective pixels which constitute the liquid crystal display part.