Method of determining OLED driving signal

• US 20060262053A1
• Filed: 05/18/2006
• Published: 11/23/2006
• Est. Priority Date: 05/19/2005
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Lee, Chung-Chun, Shih, Li-Wei
• Granted Patent: US 7,742,026 B2
• Time in Patent Office: Days
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 3/3225 using an active matrix

Abstract

A method of determining driving signals for a four-color organic electroluminescence device is provided. The driving signals are for displaying a predetermined color. A three-color organic electroluminescence device is a reference. The method comprises: a) defining a value of a white signal equal to the lowest value of a red reference signal, a green reference signal and a blue reference signal; b) defining a value of a red signal equal to the value difference between the red reference signal and the white signal, defining a value of a green signal equal to the value difference between the green reference signal and the white signal, defining a value of a blue signal equal to the value difference between the blue reference signal and the white signal; and c) adjusting the values of the red signal, the green signal or the blue signal for compensating color shifting.

Claims

1. A method of determining driving signals for a four-color organic electroluminescence device, wherein said driving signals include a white signal, a red signal, a green signal, and a blue signal to drive the pixel presenting a predetermined color, a three-color organic electroluminescence device being used as a reference, a pixel of the three-color organic electroluminescence device being driven by a red reference signal, a green reference signal, and a blue reference signal to present said predetermined color, the method comprising:

defining a value of the white signal to be the lowest value among the red reference signal, the green reference signal, and the blue reference signal;

defining a value of the red signal equal to the difference between the value of the red reference signal and the white signal, defining a value of the green signal equal to the difference between the value of the green reference signal and the white signal, and defining a value of the blue signal equal to the difference between the value of the blue reference signal and the white signal; and

adjusting the values of the red signal, the green signal, or the blue signal to compensate color shifting resulted from a four-color organic electroluminescence device of the pixel.

2. The method of claim 1, wherein the adjustment includes a white balance process comprising:

detecting a difference between a first color displayed while only turning on the white sub-pixel of a four-color organic electroluminescence device and a pure white;

compensating the first color to the pure white by using one or combination of the red sub-pixel, the green sub-pixel and the blue sub-pixel; and

recording the values of the red sub-pixel, the green sub-pixel and the blue sub-pixel to be a compensating red signal, a compensating green signal, and a compensating blue signal.

3. The method of claim 1, wherein adjustment includes a red gamma adjusting process, comprising:

only turning on the red sub-pixel of the four-color organic electroluminescence device;

adjusting the value of the red signal so that the red gamma curve matches a predetermined red gamma curve; and

recording the ratio of the value of the red signal before adjustment to the value of the red signal value after adjustment to be an adjusting coefficient.

4. The method of claim 1, wherein the adjustment includes a green gamma adjusting process including:

only turning on the green sub-pixel of the four-color organic electroluminescence device;

adjusting the value of the green signal so that the green gamma curve matches a predetermined green gamma curve; and

recording the ratio of the value of the green signal before adjustment to the value of the green signal value after adjustment to be an adjusting coefficient.

5. The method of claim 1, wherein the adjusting step includes a blue gamma adjusting process including:

only turning on the blue sub-pixel of the four-color organic electroluminescence device;

adjusting the value of the blue signal so that the blue gamma curve matches a predetermined blue gamma curve; and

recording the ratio of the value of the blue signal before adjustment to the value of the blue signal value after adjustment to be an adjusting coefficient.

6. A method of determining driving signals for a organic electroluminescence device having a white sub-pixel, a red sub-pixel, a green sub-pixel, and a blue sub-pixel, the driving signals including a white signal, a red signal, a green signal, and a blue signal, the method comprising following steps in order:

shutting the white sub-pixel and using the red sub-pixel, the green sub-pixel, and the blue sub-pixel to display a predetermined color;

recording the lowest value among the red reference signal, the green reference signal, and the blue reference signal;

tuning on the white sub-pixel and defining the white signal equal to said lowest value;

adjusting the values of the red signal, the green signal, or the blue signal to display the predetermined color by the pixel; and

recording values of the red signal, the green signal, and the blue signal.

7. The method of claim 6, wherein the adjusting step includes a white balance process including:

detecting a difference between a first color displayed while only turning on the white sub-pixel of a four-color organic electroluminescence device and a pure white;

compensating the first color to the pure white by using one or combination of the red sub-pixel, the green sub-pixel and the blue sub-pixel; and

recording the values of the red sub-pixel, the green sub-pixel and the blue sub-pixel to be a compensating red signal, a compensating green signal, and a compensating blue signal.

8. The method of claim 6, wherein the adjusting step includes a red gamma adjusting process including:

only turning on the red sub-pixel of the four-color organic electroluminescence device;

adjusting the value of the red signal so that the red gamma curve matches a predetermined red gamma curve; and

recording the ratio of the value of the red signal before adjustment to the value of the red signal value after adjustment to be an adjusting coefficient.

9. The method of claim 6, wherein the adjusting step includes a green gamma adjusting process including:

only turning on the green sub-pixel of the four-color organic electroluminescence device;

adjusting the value of the green signal so that the green gamma curve matches a predetermined green gamma curve; and

recording the ratio of the value of the green signal before adjustment to the value of the green signal value after adjustment to be an adjusting coefficient.

10. The method of claim 6, wherein the adjusting step includes a blue gamma adjusting process including:

only turning on the blue sub-pixel of the four-color organic electroluminescence device;

adjusting the value of the blue signal so that the blue gamma curve matches a predetermined blue gamma curve; and

recording the ratio of the value of the blue signal before adjustment to the value of the blue signal value after adjustment to be an adjusting coefficient

11. A method of determining driving signals for a pixel of a four-color organic electroluminescence device, wherein said driving signals include a white signal, a first-color signal, a second-color signal and a third-color signal to drive the pixel presenting a predetermined color, a three-color organic electroluminescence device being used as a reference, a pixel of the three-color organic electroluminescence device driven by a first-color reference signal, a second-color reference signal and a third-color reference signal to present said predetermined color, the method comprising following steps:

defining a value of the white signal equal to one of the first-color reference signal, the second-color reference signal and the third-color reference signal that having the lowest value;

defining a value of the first-color signal equal to the value difference between the first-color reference signal and the white signal, defining a value of the second-color signal equal to the value difference between the second-color reference signal and the white signal, defining a value of the third-color signal equal to the value difference between the third-color reference signal and the white signal; and

performing an adjusting step to adjust the values of the first-color signal, the second-color signal or the third-color signal for compensating color shifting resulted from a white OLED of the pixel.

12. The method of claim 11, wherein the adjusting step includes a white balance process including:

detecting a difference between a first color displayed while only turning on the white sub-pixel of a four-color organic electroluminescence device and a pure white;

compensating the first color to the pure white by using one or combination of the red sub-pixel, the green sub-pixel and the blue sub-pixel; and

recording the values of the red sub-pixel, the green sub-pixel and the blue sub-pixel to be a compensating red signal, a compensating green signal, and a compensating blue signal.

13. The method of claim 11, wherein the adjusting step includes a first-color gamma adjusting process including:

only turning on the red sub-pixel of the four-color organic electroluminescence device;

adjusting the value of the red signal so that the red gamma curve matches a predetermined red gamma curve; and

recording the ratio of the value of the red signal before adjustment to the value of the red signal value after adjustment to be an adjusting coefficient.

14. The method of claim 11, wherein the adjusting step includes a second-color gamma adjusting process including:

only turning on the green sub-pixel of the four-color organic electroluminescence device;

adjusting the value of the green signal so that the green gamma curve matches a predetermined green gamma curve; and

recording the ratio of the value of the green signal before adjustment to the value of the green signal value after adjustment to be an adjusting coefficient.

15. The method of claim 11, wherein the adjusting step includes a third-color gamma adjusting process including:

only turning on the blue sub-pixel of the four-color organic electroluminescence device;

adjusting the value of the blue signal so that the blue gamma curve matches a predetermined blue gamma curve; and

recording the ratio of the value of the blue signal before adjustment to the value of the blue signal value after adjustment to be an adjusting coefficient.