Self-emission type display device

• US 20070229415A1
• Filed: 12/19/2006
• Published: 10/04/2007
• Est. Priority Date: 03/31/2006
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Group)
• Original Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Inventors: Akimoto, Hajime, Kasai, Naruhiko, Satou, Toshihiro
• Granted Patent: US 8,269,695 B2
• Time in Patent Office: Days
• US Class Current: 345/77
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• 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 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

A self-emission type display device is disclosed. A current comparator circuit (47) in a data line drive circuit having a current compensating function (2) detects only the result of size comparison between the current amount due to the degeneration of a self-emission element and a reference value. The reduction of the current amount below the reference value is stored by being added to the least significant bits of a display data storage circuit (30). In accordance with the display data read from the storage circuit (30), a D/A conversion circuit (41) generates a write signal voltage.

Claims

1. A self-emission type display device comprising:

a display panel including a plurality of data lines, a plurality of scanning lines crossing the data lines, a plurality of power lines and a plurality of self-emission pixels connected to the data lines, the scanning lines and the power lines;

a data line drive circuit for applying a drive signal to the data-lines;

a scanning line drive circuit for selecting the pixels to be driven to the scanning lines;

a display control circuit for generating a control signal to control the data line drive circuit and the scanning line drive circuit based on the input display data and the timing signal;

a voltage generating circuit for generating a drive voltage to be applied to the power lines;

a current detection circuit for comparing the current for each of the power lines with a reference value; and

a storage circuit;

wherein the display control circuit stores, in the storage circuit, the display data and the result of current comparison by the current detection circuit corresponding to the display position on the display panel at an appropriate timing, and collectively reads, from the storage circuit, the display data and the current comparison result corresponding to the display position on the display panel; and

wherein the data line drive circuit determines the drive signal based on the display data and the current comparison result collectively read from the storage circuit.

2. A self-emission type display device according to claim 1,

wherein the display position on the display panel to be-detected by the current detection circuit is the whole area on the display panel.

3. A self-emission type display device according to claim 1,

wherein the display position on the display panel to be detected by the current detection circuit is a predetermined partial area on the display panel.

4. A self-emission type display device according to claim 1,

wherein the data line drive circuit includes:

a first analog conversion circuit for converting the display data into an analog value and a second analog circuit for converting the current comparison result into an analog value; and

an adder circuit for adding the analog display data and the analog current comparison result.

5. A self-emission type display device according to claim 1,

wherein the current comparison result corresponding to the display position on the display panel is the data configured of the number of bits corresponding to the number of times detected by the display control circuit.

6. A self-emission type display device according to claim 1,

wherein the current comparison result corresponding to the display position on the display panel is the data configured of one bit indicating whether the current for each of the power lines is smaller than the reference value.

7. A self-emission type display device comprising:

a display panel including a plurality of data lines, a plurality of scanning lines crossing the data lines, a plurality of power lines and a plurality of self-emission pixels connected to the data lines, the scanning lines and the power lines;

a data line drive circuit for applying a drive signal corresponding to the display data to the data lines;

a scanning line drive circuit for applying a select signal for selecting the pixels to be driven to the scanning lines;

a voltage generating circuit for generating a drive voltage to be applied to the power lines;

a current detection circuit for detecting the current of a pixel and outputting a 1-bit data indicating whether the current of the pixel is smaller than a reference value; and

a correction circuit for adding the 1-bit data to the display data.

8. A self-emission type display device according to claim 7,

wherein the correction circuit adds the 1-bit data to the least significant bits of the display data.

9. A self-emission type display device according to claim 7,

wherein the correction circuit adds the 1-bit data of the previous frame period to the display data for the next and subsequent frame periods.

10. A self-emission type display device according to claim 7,

wherein the current detection circuit detects the current for each power line each time of scanning by the scanning drive circuit thereby to detect the current for each pixel,

wherein the 1-bit data indicates whether the current for each pixel is smaller than the reference value, and

wherein the correction circuit adds the 1-bit data to the display data for each pixel.

11. A self-emission type display device according to claim 10,

wherein the current detection circuit includes:

a detection circuit arranged for each of the power lines to detect the current for each of the power lines; and

a comparator circuit arranged for each of the powers line to compare the current for each power line with the reference vale each time of scanning by the scanning line drive circuit, and to output the comparison result as the 1-bit data.

12. A self-emission type display device according to claim 11,

wherein the current detection circuit includes a conversion circuit for converting the 1-bit parallel data output from each comparison circuit into a serial data.

13. A self-emission type display device according to claim 11,

wherein the detection circuit converts the current for each of the power lines into a voltage value;

and

wherein the comparator circuit compares the voltage value for each of the power lines with the reference value and outputs the comparison result as the 1-bit data.

14. A self-emission type display device according to claim 7,

wherein the current detection circuit outputs, each time of detection, a 1-bit data indicating whether the current for each of the pixels is smaller than a reference value, and

wherein the correction circuit adds the bit data in the number of bits corresponding to the number of times detected by the current detection circuit to the display data.

15. A self-emission type display device according to claim 7,

wherein the data line drive circuit generates a drive signal corresponding to the display data and a drive signal corresponding to the 1-bit data, and

wherein the correction circuit adds the drive signal corresponding to the 1-bit data to the drive signal corresponding to the display data.