Self-emission type display device

• US 8,269,695 B2
• Filed: 12/19/2006
• Issued: 09/18/2012
• Est. Priority Date: 03/31/2006
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated), Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Inventors: Kasai, Naruhiko, Akimoto, Hajime, Satou, Toshihiro
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): MERKOULOVA, OLGA VLADIMIROVNA
• Application Number:
  US11/640,845
• Publication Number:
  US 20070229415A1
• Time in Patent Office: 2,100 Days
• Field of Search: 345/82, 345/36, 345/45, 345/39, 345/33, 345 76- 78, 345 55- 56, 345530-574, 315/169.3, 315/169.1
• US Class Current: 345/76
• 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 applying a drive signal to the scanning lines, and for selecting pixels to be driven;

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

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

a current detection circuit for detecting a current flowing through a pixel having been affected due to sticking, and for comparing an amount of the current detected with a reference value supplied by the voltage generating circuit; and

a storage circuit provided within the display control circuit;

wherein the storage circuit is arranged to store the display data with adding predetermined data if the amount of the current detected has a predetermined relationship with the reference value, the display data to be stored in the storage circuit including the predetermined data indicating a current change due to sticking stored separately from the other portion in the display data; and

wherein the data line drive circuit determines a strength of the drive signal based on the inputted display data with the predetermined data, so that each of inputted display data with the predetermined data is outputted at a time through a corresponding pixel according to the strength of the drive signal having been determined, the display data with the predetermined data to be outputted at a time including a predetermined number of bits for each corresponding pixel.

2. The self-emission type display device according to claim 1, wherein a display position on the display panel to be detected by the current detection circuit is an entire area on the display panel.

3. The self-emission type display device according to claim 1, wherein a display position on the display panel to be detected by the current detection circuit is a predetermined partial area on the display panel.

4. The 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;

a second analog circuit for converting a current comparison result from the current detection circuit into an analog value; and

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

5. The self-emission type display device according to claim 1, wherein the predetermined data to be added to the inputted display data shows a number of bits corresponding to a number of times detected by the display control circuit.

6. The self-emission type display device according to claim 1, wherein the predetermined relationship shows that the amount of the current detected is smaller than the reference value.

7. The self-emission type display device according to claim 1, wherein the predetermined data comprises 1-bit data.

8. The self-emission type display device according to claim 1, wherein the predetermined number of bits for each corresponding pixel comprises seven.

9. 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 applying a drive signal to the scanning lines, and for selecting pixels to be driven;

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

a current detection circuit for detecting a current flowing through a pixel having been affected due to sticking, and outputting 1-bit data indicating a change in current due to sticking when the current is smaller than the current detected with a reference value supplied by the voltage generating circuit; and

a correction circuit for adding the 1-bit data to the display data for storage, during a write operation, such that the display data to be stored includes the 1-bit data indicating the current change due to sticking stored separately from the other portion in the display data, and for subsequent output, during a read operation, such that the display data with the 1-bit data to be outputted includes a predetermined number of bits for each pixel.

10. The self-emission type display device according to claim 9, wherein the correction circuit adds the 1-bit data to the least significant bits of the display data.

11. The self-emission type display device according to claim 9, 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.

12. The self-emission type display device according to claim 9, 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,

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

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

13. The self-emission type display device according to claim 9, wherein:

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

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

14. The self-emission type display device according to claim 9, 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

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

15. The self-emission type display device according to claim 12, 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 value each time of scanning by the scanning line drive circuit, and to output the current comparison result as the 1-bit data.

16. The self-emission type display device according to claim 15, wherein the current detection circuit includes a conversion circuit for converting the 1-bit parallel data output from each comparison circuit into serial data.

17. The self-emission type display device according to claim 15, wherein:

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

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

18. 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 to apply a drive signal to the data lines;

a scanning line drive circuit to apply a drive signal to the scanning lines, and to select pixels to be driven;

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

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

a current detection circuit arranged to detect a current flowing through a pixel having been affected due to sticking, and to make a comparison between an amount of the current detected with a reference value supplied by the voltage generating circuit; and

a storage circuit provided within the display control circuit, to store the display data with predetermined data if the amount of the current detected has a predetermined relationship with the reference value, the display data to be stored including the predetermined data indicative of a current change due to sticking stored separately from the other portion in the display data,

wherein the data line drive circuit determines a strength of the drive signal based on the inputted display data with the predetermined data, so that each of inputted display data with the predetermined data is outputted through a corresponding pixel according to the strength of the drive signal, the display data with the predetermined data to be outputted including a predetermined number of bits for each pixel.

19. The self-emission type display device according to claim 18, wherein a display position on the display panel to be detected by the current detection circuit is an entire area on the display panel or a predetermined partial area on the display panel.

20. The self-emission type display device according to claim 18, wherein the predetermined data to be added to the inputted display data shows a number of bits corresponding to a number of times detected by the display control circuit.

21. The self-emission type display device according to claim 18, wherein the predetermined data comprises 1-bit data.