Systems and methods of pixel calibration based on improved reference values
What is disclosed are systems and methods of compensation of images produced by active matrix light emitting diode device (AMOLED) and other emissive displays. The electrical output of a pixel is compared with a reference value to adjust an input for the pixel. In some embodiments an integrator is used to integrate a pixel current and a reference current using controlled integration times to generate values for comparison.
1. A method for compensating an image produced by an emissive display system having pixels, each pixel having alight-emitting device, the method comprising:
comparing an electrical output of a pixel with a reference, generating at least one comparison value; and
adjusting an input for the pixel with use of the at least one comparison value.
2. The method of claim 1 , wherein said reference comprises a reference signal.
3. The method of claim 2 , wherein said reference signal comprises an analog reference signal.
4. The method of claim 2 , wherein said reference signal comprises one of a reference current and a reference voltage.
5. The method of claim 1 , wherein said reference comprises a reference charge.
6. The method of claim 1 , wherein said reference comprises a digital reference value.
7. The method of claim 1 , wherein said input for the pixel comprises a programming input for the pixel.
8. The method of claim 7 , wherein said adjusting comprises updating calibration data for compensating said programming input for the pixel.
9. The method of claim 1 , wherein said input for the pixel is adjusted repeatedly until, at a final value of the adjusted input for the pixel, said comparison value equals a predefined value.
10. The method of claim 9 , further comprising updating calibration data to compensate a programming of the pixel with use of the final value of the adjusted input for the pixel.
11. The method of claim 1 , wherein comparing the electrical output of the pixel with the reference comprises integrating the electrical output of the pixel.
12. The method of claim 1 , wherein comparing the electrical output of the pixel with the reference comprises sampling the electrical output of the pixel.
13. The method of claim 1 , wherein the reference comprises a reference signal, and wherein comparing the electrical output of the pixel with the reference comprises integrating the reference signal.
14. The method of claim 13 , wherein the reference signal is integrated for an integration time based on an expected magnitude of the electrical output of the pixel.
15. The method of claim 1 , wherein comparing the electrical output of the pixel with the reference comprises combining the electrical output of the pixel with the reference.
16. The method of claim 1 , wherein the reference comprises a reference signal, and wherein comparing the electrical output of the pixel with the reference comprises integrating the electrical output of the pixel, integrating the reference signal, and combining the integrated electrical output of the pixel and the integrated reference signal in an integrator.
17. The method of claim 1 , wherein comparing the electrical output of the pixel with the reference comprises sampling the electrical output of the pixel and, in a capacitor, combining the sampled electrical output of the pixel and the reference.
18. The method of claim 17 , wherein said reference comprises an analog reference value, and wherein comparing the electrical output of the pixel with the reference comprises charging the capacitor to the analog reference value.
19. The method of claim 1 , further comprising determining a value of the reference with use of an expected magnitude of the electrical output of the pixel.
20. The method of claim 1 , further comprising prior to comparing the electrical output of the pixel with the reference, measuring the electrical output of the pixel.