Semiconductor device

• US 8,519,981 B2
• Filed: 11/08/2010
• Issued: 08/27/2013
• Est. Priority Date: 11/12/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kurokawa, Yoshiyuki, Ikeda, Takayuki
• Primary Examiner(s): Wozniak, James
• Assistant Examiner(s): Cohen, Yaron
• Application Number:
  US12/941,270
• Publication Number:
  US 20110109593A1
• Time in Patent Office: 1,023 Days
• Field of Search: 359/724, 359/725, 382/100, 382/141, 345/175, 348/222.1, 348/E05.024
• 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 2320/0295 by monitoring each display pixel
• CPC Class Codes: G09G 2360/14 Detecting light within display terminals, e.g. using a single or a plurality of photosensors
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: H01L 27/146 Imager structures
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors

Abstract

An object is to reduce noise caused by variations in characteristics of photosensors provided for each pixel in a display panel having an image capturing function by the photosensors and to provide an image with high precision. A display device includes a display panel including photosensors arranged in matrix and an image processing circuit, in which the photosensors captures a black image and an image of an object; and the image processing circuit produces an image having image data (Y−X) using image data X of the black image and image data Y of the image of the object.

Claims

1. A display device comprising:

a display panel having a photosensor; and

an image processing circuit operationally connected to the display panel,

wherein the photosensor is configured to capture a black image, a white image and an image of an object,

wherein the image processing circuit is configured to produce an image having data represented by a formula;

MAX×

(Z−

X)/(Y−

X),

wherein MAX represents a maximum value of a gray scale,

wherein X represents data of the black image,

wherein Y represents data of the white image, and

wherein Z represents data of the image of the object.

2. The display device according to claim 1, wherein the photosensor is configured to capture the black image and the white image in a reset operation.

3. The display device according to claim 1, further comprising a memory device configured to store the image of the object, the black image and the white image.

4. A semiconductor device comprising:

an input portion having a photosensor; and

an image processing circuit operationally connected to the input portion,

wherein the photosensor is configured to capture a black image, a white image and an image of an object,

wherein the image processing circuit is configured to produce an image having data represented by a formula;

MAX×

(Z−

X)/(Y−

X),

wherein MAX represents a maximum value of a gray scale,

wherein X represents data of the black image,

wherein Y represents data of the white image, and

wherein Z represents data of the image of the object.

5. The semiconductor device according to claim 4, wherein the photosensor is configured to capture the black image and the white image in a reset operation.

6. The semiconductor device according to claim 4, further comprising a memory device configured to store the image of the object, the black image and the white image.

7. A driving method of a semiconductor device comprising:

capturing a black image, a white image, and an image of an object by a photosensor; and

producing an image having data represented by a formula;

MAX×

(Z−

X)/(Y−

X) by an image processing circuit operationally connected to the photosensor,

wherein X represents data of the black image,

wherein Y represents data of the white image, and

wherein Z represents data of the image of the object.

8. The driving method of a semiconductor device according to claim 7, wherein the step of capturing the black image and the white image is performed in a reset operation of the photosensor.