Optical sensor device and electronic apparatus

• US 20050082463A1
• Filed: 09/14/2004
• Published: 04/21/2005
• Est. Priority Date: 09/19/2003
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Nishi, Kazuo, Maruyama, Junya, Koyama, Jun, Osada, Takeshi, Matsuzaki, Takanori
• Granted Patent: US 7,253,391 B2
• Time in Patent Office: Days
• US Class Current: 250/214.R
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14692 Thin film technologies, e.g. amorphous, poly, micro- or nanocrystalline silicon

Abstract

In an optical sensor device employing an amorphous silicon photodiode, an external amplifier IC and the like are required due to low current capacity of the sensor element in order to improve the load driving capacity. It leads to increase in cost and mounting space of the optical sensor device. In addition, noise may easily superimpose since the photodiode and the amplifier IC are connected to each other over a printed circuit board. According to the invention, an amorphous silicon photodiode and an amplifier configured by a thin film transistor are formed integrally over a substrate so that the load driving capacity is improved while reducing cost and mounting space. Superimposing noise can be also reduced.

Claims

1. An optical sensor device comprising:

an optical sensor element; and

an amplifier circuit,

wherein the optical sensor element and the amplifier circuit are formed over a substrate.

2. An optical sensor device according to claim 1, wherein the optical sensor element comprises amorphous silicon.

3. An optical sensor device according to claim 1, wherein the optical sensor element comprises an amorphous silicon photodiode.

4. An optical sensor device according to claim 1, wherein the optical sensor element comprises polysilicon.

5. An optical sensor device according to claim 1, wherein the optical sensor element comprises a polysilicon photodiode.

6. An optical sensor device according to claim 1, wherein the amplifier circuit comprises a thin film transistor.

7. An optical sensor device according to claim 1, wherein the amplifier circuit is an operational amplifier.

8. An optical sensor device according to claim 1, wherein the amplifier circuit is a current mirror circuit.

9. An optical sensor device according to claim 1, wherein the optical sensor element and the amplifier circuit are formed over a plastic substrate.

10. An optical sensor device according to claim 1, wherein the optical sensor element and the amplifier circuit are formed over a glass substrate.

11. An electronic apparatus having an optical sensor device according to claim 1, wherein the electronic apparatus is one selected from the group consisting of a video camera, a digital camera, a head mounted display, a game machine, a car navigation system, a personal computer, a personal digital assistant and a television.

12. An optical sensor device comprising:

an optical sensor element;

an amplifier circuit; and

a feedback resistor,

wherein the amplifier circuit is an operational amplifier comprising a thin film transistor,

wherein the optical sensor element and the amplifier circuit are formed over a substrate, and

wherein the feedback resistor is provided outside of the substrate.

13. An optical sensor device according to claim 12, wherein the optical sensor element and the amplifier circuit are formed over a plastic substrate.

14. An optical sensor device according to claim 12, wherein the optical sensor element and the amplifier circuit are formed over a glass substrate.

15. An electronic apparatus having an optical sensor device according to claim 12,

wherein the electronic apparatus is one selected from the group consisting of a video camera, a digital camera, a head mounted display, a game machine, a car navigation system, a personal computer, a personal digital assistant and a television.

16. An optical sensor device comprising:

an optical sensor element;

an amplifier circuit; and

an I-V conversion resistor,

wherein the amplifier circuit is an operational amplifier comprising a thin film transistor,

wherein the optical sensor element and the amplifier circuit are formed over a substrate, and

wherein the I-V conversion resistor is provided outside of the substrate.

17. An optical sensor device according to claim 16, wherein the optical sensor element and the amplifier circuit are formed over a plastic substrate.

18. An optical sensor device according to claim 16, wherein the optical sensor element and the amplifier circuit are formed over a glass substrate.

19. An electronic apparatus having an optical sensor device according to claim 16,

wherein the electronic apparatus is one selected from the group consisting of a video camera, a digital camera, a head mounted display, a game machine, a car navigation system, a personal computer, a personal digital assistant and a television.

20. An optical sensor device comprising:

an optical sensor element;

an amplifier circuit comprising a first thin firm transistor; and

a level shift circuit comprising a second thin firm transistor,

wherein the optical sensor element, the amplifier circuit, and the level shift circuit are formed over a substrate.

21. An optical sensor device according to claim 20, wherein the level shift circuit comprises a P-channel thin film transistor and a constant current source.

22. An optical sensor device according to claim 20, wherein the level shift circuit comprises an N-channel thin film transistor and a constant current source.

23. An optical sensor device according to claim 20, further comprising four electrode terminals for connection over the substrate.

24. An optical sensor device according to claim 23, wherein two of the four electrode terminals for connection are power source terminals.

25. An optical sensor device according to claim 20, wherein the optical sensor element and the amplifier circuit are formed over a plastic substrate.

26. An optical sensor device according to claim 20, wherein the optical sensor element and the amplifier circuit are formed over a glass substrate.

27. An electronic apparatus having an optical sensor device according to claim 20, wherein the electronic apparatus is one selected from the group consisting of a video camera, a digital camera, a head mounted display, a game machine, a car navigation system, a personal computer, a personal digital assistant and a television.

28. An optical sensor device comprising:

an optical sensor element; and

an amplifier circuit,

wherein the amplifier circuit is a current mirror circuit comprising a thin film transistor, and

wherein the optical sensor element and the amplifier circuit are formed over a substrate.

29. An optical sensor device according to claim 28, wherein the thin film transistor has a multigate structure in which a thin film transistor has a plurality of gates.

30. An optical sensor device according to claim 28, wherein the current mirror circuit comprises a cascode connection.

31. An optical sensor device according to claim 28, wherein the current mirror circuit comprises a Wilson connection.

32. An optical sensor device according to claim 28, wherein the current mirror circuit comprises an improved Wilson connection.

33. An optical sensor device according to claim 28, wherein the amplification factor is controlled by changing the number, the gate length, and the channel width of a thin film transistor of the current mirror circuit.

34. An optical sensor device according to claim 28, wherein the current mirror circuit comprises an N-channel thin film transistor.

35. An optical sensor device according to claim 28, wherein the current mirror circuit comprises a P-channel thin film transistor.

36. An optical sensor device according to claim 28, further comprising two electrode terminals for connection over the substrate.

37. An optical sensor device according to claim 28, wherein the optical sensor element and the amplifier circuit are formed over a plastic substrate.

38. An optical sensor device according to claim 28, wherein the optical sensor element and the amplifier circuit are formed over a glass substrate.

39. An electronic apparatus having an optical sensor device according to claim 28, wherein the electronic apparatus is one selected from the group consisting of a video camera, a digital camera, a head mounted display, a game machine, a car navigation system, a personal computer, a personal digital assistant and a television.