DISPLAY DEVICE

• US 20110122098A1
• Filed: 11/19/2010
• Published: 05/26/2011
• Est. Priority Date: 11/20/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kurokawa, Yoshiyuki
• Granted Patent: US 9,086,760 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters

Abstract

A purpose is to enable detection of an object in a display device including a display panel provided with photosensors when the object touches the display panel and when the object does not touch the display panel. A display device includes a display panel provided with photosensors. The display device has a function of detecting an object with the photosensor when the object touches the display panel and when the object does not touch thereto. The display device has a function of changing the sensitivity of the photosensor varies depending on whether the object touches the display panel.

Claims

1. A display device comprising:

a display panel in which a photosensor is provided,

wherein the display device comprises a function of detecting an object with the photosensor, and

wherein the display device comprises a function of changing a sensitivity of the photosensor depending on whether the object touches the display panel.

2. The display device according to claim 1, wherein the sensitivity of the photosensor is changed by adjustment of voltage applied to the photosensor.

3. The display device according to claim 1,

wherein the photosensor comprises a transistor and a photodiode which is electrically connected to a gate of the transistor, and

wherein the sensitivity of the photosensor is changed by adjustment of voltage applied to the photodiode.

4. The display device according to claim 1,

wherein the photosensor comprises a transistor and a photodiode which is electrically connected to the gate of the transistor, and

wherein the sensitivity of the photosensor is changed by adjustment of voltage applied between a source and a drain of the transistor.

5. The display device according to claim 1,

wherein the photosensor comprises a function of performing reset operation, accumulating operation, and selecting operation, and

wherein the sensitivity of the photosensor is changed by time for the accumulating operation which varies depending on whether the object touches the display panel.

6. The display device according to claim 1,

wherein the photosensor comprises a function of performing reset operation, accumulating operation, and selecting operation,

wherein the sensitivity of the photosensor is changed by time for the accumulating operation which varies depending on whether the object touches the display panel,

wherein the display device has a function of performing the reset operation both in the case where the object touches the display panel and in the case where the object does not touch the display panel.

13. The display device according to claims claim 1,

wherein a photosensor control circuit controls the photosensor, and

wherein the sensitivity of the photosensor is changed by adjustment of voltage applied to the photosensor.

7. A semiconductor device comprising:

an input portion in which a photosensor is provided,

wherein the semiconductor device comprises a function of detecting an object with the photosensor, and

wherein the semiconductor device comprises a function of changing a sensitivity of the photosensor depending on whether the object touches the input portion.

8. The semiconductor device according to claim 7, wherein the sensitivity of the photosensor is changed by adjustment of voltage applied to the photosensor.

9. The semiconductor device according to claim 7,

wherein the photosensor comprises a transistor and a photodiode which is electrically connected to a gate of the transistor, and

wherein the sensitivity of the photosensor is changed by adjustment of voltage applied to the photodiode.

10. The semiconductor device according to claim 7,

wherein the photosensor comprises a transistor and a photodiode which is electrically connected to the gate of the transistor, and

wherein the sensitivity of the photosensor is changed by adjustment of voltage applied between a source and a drain of the transistor.

11. The semiconductor device according to claim 7,

wherein the photosensor comprises a function of performing reset operation, accumulating operation, and selecting operation, and

wherein the sensitivity of the photosensor is changed by time for the accumulating operation which varies depending on whether the object touches the input portion.

12. The semiconductor device according to claims claim 7,

wherein the photosensor comprises a function of performing reset operation, accumulating operation, and selecting operation,

wherein the sensitivity of the photosensor is changed by time for the accumulating operation which varies depending on whether the object touches the input portion,

wherein the display device has a function of performing the reset operation both in the case where the object touches the input portion and in the case where the object does not touch the input portion.

14. The semiconductor device according to claim 7,

wherein a photosensor control circuit controls the photosensor, and

wherein the sensitivity of the photosensor is changed by adjustment of voltage applied to the photosensor.