Display device and method of driving the same

• US 8,525,763 B2
• Filed: 07/20/2011
• Issued: 09/03/2013
• Est. Priority Date: 08/26/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Umezaki, Atsushi, Kimura, Hajime
• Primary Examiner(s): CERULLO, LILIANA P
• Application Number:
  US13/186,509
• Publication Number:
  US 20110273435A1
• Time in Patent Office: 776 Days
• Field of Search: 345 60-102, 345204-693, 362 971- 973, 315149-159, 315291-311
• US Class Current: 345/82
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• 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 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/048 using evaluation of the usage time
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 3/3225 using an active matrix

Abstract

When a light-emitting element emits light for a long time, characteristics thereof change and current flowing therethrough is reduced even in the same voltage is applied. In particular, in a case of a display device with light-emitting element, there is a problem such that burn-in is generated in a display screen. A burn-in correction period in which characteristics of a light-emitting element in each pixel are detected is provided in addition to a normal driving period in which an image is displayed. The light-emitting element can emit light which compensates the changes in the characteristics, by correcting video signals inputted to each pixel in the normal driving period according to the characteristics of the light-emitting elements obtained in the burn-in correction period.

Claims

1. A method for driving a display device comprising:

displaying an image on pixels of the display device;

proceeding to a first charging period after a predetermined time from displaying the image, and determining in the first charging period whether a battery is charged;

when it is determined that the battery is charged, proceeding to a burn-in correction period wherein characteristics of light-emitting elements in the pixels are obtained by detecting current values of the light-emitting elements by a current value detection circuit and by storing the current values into a correction circuit; and

when it is determined that the battery is not charged, proceeding to a normal driving period wherein corrected signals transmitted from the correction circuit are supplied to a gate driver of the display device.

2. The method for driving the display device according to claim 1, further comprising proceeding to a second charging period between the burn-in correction period and the normal driving period, and determining in the second charging period whether the battery is charged.

3. The method for driving the display device according to claim 1, wherein a driving frequency in the burn-in correction period is same as that in the normal driving period.

4. The method for driving the display device according to claim 1, wherein the current value detection circuit is connected to a power supply line of the light-emitting elements.

5. The method for driving the display device according to claim 1, wherein the display device is incorporated in one selected from the group consisting of a computer, an image reproducing device, a phone and a camera.

6. A method for driving a display device comprising:

displaying an image on pixels of the display device;

proceeding to a first charging period after a predetermined time from displaying the image, and determining in the first charging period whether a battery is charged;

when it is determined that the battery is charged, proceeding to a first burn-in correction period wherein characteristics of light-emitting elements in the pixels are obtained by detecting current values of the light-emitting elements one by one by a current value detection circuit and by storing the current values into a correction circuit;

proceeding to a second burn-in correction period after the first burn-in correction period, wherein characteristics of the light-emitting elements in the pixels are obtained by detecting current values of the light-emitting elements for three pixels at a same time by the current value detection circuit and by storing the current values into the correction circuit;

when it is determined that the battery is not charged, proceeding to a normal driving period wherein corrected signals transmitted from the correction circuit are supplied to a gate driver of the display device.

7. The method for driving the display device according to claim 6, further comprising proceeding to a second charging period between the second burn-in correction period and the normal driving period, and determining in the second charging period whether the battery is charged.

8. The method for driving the display device according to claim 6, wherein a driving frequency in the first burn-in correction period or the second burn-in correction period is same as that in the normal driving period.

9. The method for driving the display device according to claim 6, wherein the current value detection circuit is connected to a power supply line of the light-emitting elements.

10. The method for driving the display device according to claim 6, wherein the display device is incorporated in one selected from the group consisting of a computer, an image reproducing device, a phone and a camera.