Display device and drive method therefor

• US 20040150594A1
• Filed: 07/22/2003
• Published: 08/05/2004
• Est. Priority Date: 07/25/2002
• Status: Abandoned Application

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Osame, Mitsuaki, Koyama, Jun
• Application Number:
  US10/623,857
• Publication Number:
  US 20040150594A1
• Time in Patent Office: Days
• US Class Current: 345/82
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• 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 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/048 using evaluation of the usage time
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: G09G 3/3216 using a passive matrix
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3283 in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements
• CPC Class Codes: G09G 3/3291 in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607

Abstract

A light-emitting element has a characteristic that deterioration caused not only by aging but also by temperature change occurs. The present invention is characterized by having two compensation functions of an aging compensation function and a temperature compensation function (hereinafter collectively referred to as compensation function) in order to correct temperature change and deterioration caused by temperature change. The compensation function, which is a key of the present invention, is characterized by including: a temperature detection unit which detects an ambient temperature; a storage unit having stored therein a temperature characteristic and an aging characteristic of the light-emitting element; an arithmetic operation unit which calculates a lighting period of each pixel using an output of the temperature detection unit, the temperature characteristic, and a video signal; a count unit which detects a cumulated lighting period of each pixel using an output of the arithmetic operation unit; and a correction unit which corrects a video signal to be inputted to each pixel or a power supply potential using the aging characteristic and the cumulated lighting period.

Claims

1. A display device comprising:

a display panel which is equipped with pixels including a light-emitting element;

a temperature detection unit which detects an ambient temperature;

a storage unit having stored therein a temperature characteristic and an aging characteristic of the light-emitting element;

an arithmetic operation unit which calculates a lighting period of each pixel using an output of the temperature detection unit, the temperature characteristic, and a video signal;

a count unit which counts a cumulated lighting period of each pixel using an output of the arithmetic operation unit; and

a correction unit which corrects a video signal to be inputted to each pixel using the aging characteristic and the cumulated lighting period and supplies the corrected video signal to the display panel.

2. A display device according to claim 1,

wherein the arithmetic operation unit calculates an acceleration factor from the output of the temperature detection unit and the temperature characteristic and also calculates a lighting period of each pixel from a multiplication of the video signal and the acceleration factor.

3. A display device according to claim 1,

wherein the temperature detection unit is a light-emitting element.

4. A display device comprising:

a display panel which is equipped with pixels including a light-emitting element;

a temperature detection unit which detects an ambient temperature;

a storage unit having stored therein a temperature characteristic and an aging characteristic of the light-emitting element;

an arithmetic operation unit which calculates a lighting period of each pixel using an output of the temperature detection unit, the temperature characteristic, and a video signal;

a count unit which counts a cumulated lighting period of each pixel using an output of the arithmetic operation unit; and

a correction unit which corrects a power supply potential using the aging characteristic and the cumulated lighting period and supplies the corrected power supply potential to the display panel.

5. A display device according to claim 4,

wherein the arithmetic operation unit calculates an acceleration factor from the output of the temperature detection unit and the temperature characteristic and also calculates a lighting period of each pixel from a multiplication of the video signal and the acceleration factor.

6. A display device according to claim 4,

wherein the temperature detection unit is a light-emitting element.

7. A drive method for a display device having a display panel equipped with pixels including a light-emitting element, temperature detection unit, storage unit having stored therein a temperature characteristic and an aging characteristic of the light-emitting element, arithmetic operation unit, count unit and correction unit, comprising the steps of:

a detecting ambient temperature by the temperature detection unit;

a calculating a lighting period of each pixel using an output of the temperature detection unit, the temperature characteristic, and a video signal by the arithmetic operation unit;

a counting a cumulated lighting period of each pixel using an output of the arithmetic operation unit by the count unit;

a correcting a video signal to be inputted to each pixel using the aging characteristic and the cumulated lighting period by the correction unit; and

a displaying an image using the corrected video signal by the display panel.

8. A drive method for a display device according to claim 7,

wherein the arithmetic operation unit calculates an acceleration factor from the output of the temperature detection unit and the temperature characteristic and also calculates a lighting period of each pixel from a multiplication of the video signal and the acceleration factor.

9. A drive method for a display device according to claim 7,

wherein the temperature detection unit is a light-emitting element.

10. A drive method for a display device having a display panel equipped with pixels including a light-emitting element, temperature detection unit, storage unit having stored therein a temperature characteristic and an aging characteristic of the light-emitting element, arithmetic operation unit, count unit, and correction unit, comprising the steps of:

detecting ambient temperature by the temperature detection unit;

calculating a lighting period of each pixel using an output of the temperature detection unit, the temperature characteristic, and a video signal by the arithmetic operation unit;

counting a cumulated lighting period of each pixel using an output of the arithmetic operation unit by the count unit;

correcting a power supply potential using the aging characteristic and the cumulated lighting period by the correction unit; and

displaying an image using the corrected power supply potential by the display panel.

11. A drive method for a display device according to claim 10,

wherein the arithmetic operation unit calculates an acceleration factor from the output of the temperature detection unit and the temperature characteristic and also calculates a lighting period of each pixel from a multiplication of the video signal and the acceleration factor.

12. A drive method for a display device according to claim 10,

wherein the temperature detection unit is a light-emitting element.

13. A display device comprising:

a display panel which is equipped with pixels including a light-emitting element;

a temperature detection unit which detects an ambient temperature;

a storage unit having stored therein a temperature characteristic and an aging characteristic of the light-emitting element;

a count unit which counts a cumulated lighting period of each pixel; and

a correction unit which corrects a video signal to be inputted to each pixel using the aging characteristic and the cumulated lighting period and supplies the corrected video signal to the display panel.

14. A display device according to claim 13,

wherein the temperature detection unit is a light-emitting element.

15. A display device comprising:

a display panel which is equipped with pixels including a light-emitting element;

a temperature detection unit which detects an ambient temperature;

a storage unit having stored therein a temperature characteristic and an aging characteristic of the light-emitting element;

a count unit which counts a cumulated lighting period of each pixel; and

a correction unit which corrects a power supply potential using the aging characteristic and the cumulated lighting period and supplies the corrected power supply potential to the display panel.

16. A display device according to claim 15, wherein the temperature detection unit is a light-emitting element.

17. A drive method for a display device having a display panel equipped with pixels including a light-emitting element, temperature detection unit, storage unit having stored therein a temperature characteristic and an aging characteristic of the light-emitting element, count unit and correction unit, comprising the steps of:

detecting ambient temperature by the temperature detection unit;

counting a cumulated lighting period of each pixel by the count unit;

correcting a video signal to be inputted to each pixel using the aging characteristic and the cumulated lighting period by the correction unit; and

displaying an image using the corrected video signal by the display panel.

18. A drive method for a display device according to claim 17,

wherein the temperature detection unit is a light-emitting element.

19. A drive method for a display device having a display panel equipped with pixels including a light-emitting element, temperature detection unit, storage unit having stored therein a temperature characteristic and an aging characteristic of the light-emitting element, arithmetic operation unit, count unit, and correction unit, comprising the steps of:

detecting ambient temperature by the temperature detection unit;

counting a cumulated lighting period of each pixel by the count unit;

correcting a power supply potential using the aging characteristic and the cumulated lighting period by the correction unit; and

displaying an image using the corrected power supply potential by the display panel.

20. A drive method for a display device according to claim 19,

wherein the temperature detection unit is a light-emitting element.