Display device and method of manufacturing the same

• US 20020011978A1
• Filed: 06/04/2001
• Published: 01/31/2002
• Est. Priority Date: 06/06/2000
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kimura, Hajime, Arai, Yasuyuki, Yamazaki, Shunpei
• Granted Patent: US 6,995,753 B2
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• 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 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/30 using electroluminescent panels
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

There is provided a display device capable of automatically controlling a luminance in response to a brightness of a surrounding. The display device has a gamma correction circuit for converting an image signal voltage into a drive voltage for gray scale display and a photosensor for controlling an input and output voltage characteristic of the gamma correction circuit in response to the brightness of the surrounding. In this case, the gamma correction circuit for converting the image signal voltage into the driver voltage for gray scale display is formed on a first substrate. The photosensor for controlling the input and output voltage characteristic of the gamma correction circuit in response to the brightness of the surrounding is formed on a second substrate. The second substrate is fixed to the first substrate.

Claims

1. A display device comprising:

a gamma correction circuit;

an image signal processing circuit connected with an output line of said gamma correction circuit; and

a plurality of photosensors for changing an output voltage of the gamma correction circuit in accordance with a brightness of a surrounding.

2. A display device according to claim 1, wherein said display device is a liquid crystal display device or an electroluminescence display device.

3. A display device according to claim 1, wherein each of said photosensors has a photoelectric conversion layer comprising amorphous silicon.

4. A display device according to claim 1, wherein said display device is incorporated into an electronic equipment selected from the group consisting of a video camera, a digital camera, a projector, a head-mounted display, a car navigation system, a car stereo, a personal computer, and a portable information terminal.

5. A display device comprising:

a first substrate;

a second substrate fixed to said first substrate;

a gamma correction circuit;

an image signal processing circuit connected with an output line of said gamma correction circuit; and

a plurality of photosensors, formed on said second substrate, for changing an output voltage of said gamma correction circuit in accordance with a brightness of a surrounding.

6. A display device according to claim 5, wherein said display device is a liquid crystal display device or an electroluminescence display device.

7. A display device according to claim 5, wherein each of said photosensors has a photoelectric conversion layer comprising amorphous silicon.

8. A display device according to claim 5, wherein said display device is incorporated into an electronic equipment selected from the group consisting of a video camera, a digital camera, a projector, a head-mounted display, a car navigation system, a car stereo, a personal computer, and a portable information terminal.

9. A display device comprising:

a plurality of photosensors for detecting a brightness of a surrounding; and

a gamma correction circuit for outputting a voltage for determining a period that a pixel is in a light state in accordance with electrical signals from said plurality of photosensors.

10. A display device according to claim 9, wherein said display device is a liquid crystal display device or an electroluminescence display device.

11. A display device according to claim 9, wherein each of said photosensors has a photoelectric conversion layer comprising amorphous silicon.

12. A display device according to claim 9, wherein said display device is incorporated into an electronic equipment selected from the group consisting of a video camera, a digital camera, a projector, a head-mounted display, a car navigation system, a car stereo, a personal computer, and a portable information terminal.

13. A display device comprising:

a plurality of photosensors provided on an peripheral portion of a substrate;

a source follower circuit connected with said plurality of photosensors;

a gamma correction circuit connected with said source follower circuit;

an image signal amplifying circuit connected with said gamma correction circuit;

a source signal line driver circuit connected with said image signal amplifying circuit; and

a pixel portion which is connected with said source signal line driver circuit and formed on said substrate.

14. A display device according to claim 13, wherein said pixel portion has at least a pixel electrode, a liquid crystal layer, and a counter electrode.

15. A display device according to claim 13, wherein said pixel portion has at least a pixel electrode and a light emitting layer.

16. A display device according to claim 13, wherein each of said photosensors has a photoelectric conversion layer comprising amorphous silicon.

17. A display device according to claim 13, wherein said display device is incorporated into an electronic equipment selected from the group consisting of a video camera, a digital camera, a projector, a head-mounted display, a car navigation system, a car stereo, a personal computer, and a portable information terminal.

18. A display device comprising:

a first substrate;

a second substrate;

a plurality of photosensors which are formed on said second substrate and fixed to an outer portion of said first substrate;

a source follower circuit connected with said plurality of photosensors;

a gamma correction circuit connected with said source follower circuit;

an image signal amplifying circuit connected with said gamma correction circuit;

a source signal line driver circuit connected with said image signal amplifying circuit; and

a pixel portion which is connected with said source signal line driver circuit and formed on said first substrate.

19. A display device according to claim 18, wherein said pixel portion has at least a pixel electrode, a liquid crystal layer, and a counter electrode.

20. A display device according to claim 18, wherein said pixel portion has at least a pixel electrode and a light emitting layer.

21. A display device according to claim 18, wherein each of said photosensors has a photoelectric conversion layer comprising amorphous silicon.

22. A display device according to claim 18, wherein said display device is incorporated into an electronic equipment selected from the group consisting of a video camera, a digital camera, a projector, a head-mounted display, a car navigation system, a car stereo, a personal computer, and a portable information terminal.

23. A display device comprising:

a gamma correction circuit;

an image signal processing circuit connected with an output line of said gamma correction circuit; and

a plurality of photosensors for changing an output voltage of the gamma correction circuit in accordance with a brightness of a surrounding,

wherein each of said photosensors has a photoelectric conversion layer comprising amorphous silicon.

24. A display device according to claim 23, wherein said display device is a liquid crystal display device or an electroluminescence display device.

25. A display device according to claim 23, wherein said display device is incorporated into an electronic equipment selected from the group consisting of a video camera, a digital camera, a projector, a head-mounted display, a car navigation system, a car stereo, a personal computer, and a portable information terminal.

26. A method of manufacturing a display device, comprising the steps of:

forming a pixel portion using a thin film transistor on a first substrate;

forming a photosensor on a second substrate; and

fixing the second substrate to said first substrate.

27. A method of manufacturing a display device according to claim 26, wherein in the pixel portion at least, a pixel electrode, a liquid crystal layer, and a counter electrode are formed.

28. A method of manufacturing a display device according to claim 26, wherein in the pixel portion, at least a pixel electrode and a light emitting layer are formed.

29. A method of manufacturing a display device according to claim 26, wherein each of said photosensors has a photoelectric conversion layer comprising amorphous silicon.

30. A method of manufacturing a display device according to claim 26, wherein said display device is incorporated into an electronic equipment selected from the group consisting of a video camera, a digital camera, a projector, a head-mounted display, a car navigation system, a car stereo, a personal computer, and a portable information terminal.

31. A method of manufacturing a display device, comprising the steps of:

forming a pixel portion, a driver circuit for driving said pixel portion, and a control circuit for controlling a brightness of said pixel portion, using a thin film transistor, on a first substrate;

forming a photosensor on a second substrate; and

fixing said second substrate to said first substrate to electrically connect said control circuit with said photosensor.

32. A method of manufacturing a display device according to claim 31, wherein in the pixel portion at least, a pixel electrode, a liquid crystal layer, and a counter electrode are formed.

33. A method of manufacturing a display device according to claim 31, wherein in the pixel portion, at least a pixel electrode and a light emitting layer are formed.

34. A method of manufacturing a display device according to claim 31, wherein each of said photosensors has a photoelectric conversion layer comprising amorphous silicon.

35. A method of manufacturing a display device according to claim 31, wherein said display device is incorporated into an electronic equipment selected from the group consisting of a video camera, a digital camera, a projector, a head-mounted display, a car navigation system, a car stereo, a personal computer, and a portable information terminal.