CRACK DETECTOR AND METHOD OF DRIVING CRACK DETECTOR

• US 20170192065A1
• Filed: 12/16/2016
• Published: 07/06/2017
• Est. Priority Date: 12/30/2015
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: LEE, Seung-Jun, SEO, O-Gweon, KIM, Hong-Kwon
• Granted Patent: US 10,267,866 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 31/44 Testing lamps
• CPC Class Codes: G09G 2300/043 Compensation electrodes or other additional electrodes in matrix displays related to distortions or compensation signals, e.g. for modifying TFT threshold voltage in column driver
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2330/00 Aspects of power supply; Aspects of display protection and defect management
• CPC Class Codes: G09G 2330/027 Arrangements or methods related to powering off a display
• CPC Class Codes: G09G 2330/12 Test circuits or failure detection circuits included in a display system, as permanent part thereof
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• 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

Abstract

A method of driving a crack detector of an organic light emitting display device according to example embodiments includes: determining an image load of a display panel with respect to image data corresponding to an emission period of the organic light emitting display device when it is driven according to a simultaneous emission driving method, calculating a first sensing value corresponding to a power current that flows into a power supply during the emission period, determining a first crack reference value based on the image load, and determining whether the display panel is cracked by comparing the first crack reference value with the first sensing value.

Claims

1. A method of driving a crack detector of an organic light emitting display device, the method comprising:

determining an image load of a display panel with respect to image data corresponding to an emission period of the organic light emitting display device when the organic light emitting display device is driven according to a simultaneous emission driving method;

calculating a first sensing value corresponding to a power current that flows into a power supply during the emission period;

determining a first crack reference value based on the image load; and

determining whether the display panel is cracked by comparing the first crack reference value with the first sensing value.

2. The method of claim 1, wherein the calculating a first sensing value further comprises:

detecting the power current multiple times during a predetermined sensing period within the emission period; and

determining the first sensing value based on a plurality of the detected power currents.

3. The method of claim 2, wherein the first sensing value further corresponds to one of an average of the detected power currents, a maximum value of the detected power currents, and a minimum value of the detected power currents.

4. The method of claim 2, wherein the first crack reference value has a predetermined tolerance range.

5. The method of claim 4, wherein the determining whether the display panel is cracked further comprises:

comparing the first sensing value with the first crack reference value; and

shutting down power supply when the first sensing value is not within the tolerance range of the first crack reference value.

6. The method of claim 2, further comprising:

calculating a second sensing value corresponding to a power current that flows into the power supply during a data writing period of a non-emission period of the organic light emitting display device; and

comparing a second crack reference value with the second sensing value.

7. The method of claim 6, wherein the second crack reference value corresponds to zero.

8. The method of claim 6, wherein the second crack reference value has a predetermined tolerance range.

9. The method of claim 8, wherein the comparing a second crack reference value with the second sensing value further comprises:

determining the image load based on the image data corresponding to the non-emission period; and

shutting down power supply when the second sensing value is not within the tolerance range of the second crack reference value.

10. The method of claim 9, wherein a second crack reference value variation is determined according to an image load variation and is less than a first crack reference value variation depending on the image load variation.

11. The method of claim 1, wherein the image load corresponds to an average luminance of the frame.

12. The method of claim 1, wherein the image load corresponds to an average grayscale of the frame.

13. A crack detector for an organic light emitting display device, the crack detector comprising:

a current detector disposed at an external circuit board of a display panel which is configured to be driven according to a simultaneous emission driving method and configured to calculate a sensing value of a power current that flows into a power supply during an emission period;

an image load determiner configured to determine a crack reference value corresponding to an image load of the display panel; and

a power controller configured to perform a comparison of the crack reference value to the sensing value, and to control the power supply according to the comparison.

14. The crack detector of claim 13, wherein the current detector comprises:

a sensing resistor configured to detect the power current during a predetermined sensing period in the emission period; and

a sensing value calculator configured to convert a plurality of the detected power currents into a digital signal, and to calculate the sensing value based on the digital signal.

15. The crack detector of claim 14, wherein the sensing value calculator is configured to calculate at least one of an average of the detected power currents, a maximum value of the detected power currents, and a minimum value of the detected power currents.

16. The crack detector of claim 14, wherein the image load determiner is configured to calculate the image load based on grayscales of image data, and to determine the crack reference value corresponding to the image load.

17. The crack detector of claim 16, wherein the image load determiner comprises:

a memory configured to store a plurality of the determined crack reference values according to a plurality of levels of the image load.

18. The crack detector of claim 16, wherein the crack reference value has a predetermined tolerance range.

19. The crack detector of claim 18, wherein the power controller is configured to output a shut down signal to shut down the power supply when the sensing value is not within the tolerance range of the crack reference value.

20. The crack detector of claim 16, wherein the current detector is further configured to calculate the sensing value during a data writing period in a non-emission period, and

wherein the power controller is configured to compare the crack reference value with the sensing value to control a supply of power.