Display system with compensation techniques and/or shared level resources
A voltage-programmed display system allows measurement of effects on pixels in a panel that includes both active pixels and reference pixels coupled to a supply line and a programming line. The reference pixels are controlled so that they are not subject to substantial changes due to aging and operating conditions over time. A readout circuit is coupled to the active pixels and the reference pixels for reading at least one of current, voltage or charge from the pixels when they are supplied with known input signals. The readout circuit is subject to changes due to aging and operating conditions over time, but the readout values from the reference pixels are used to adjust the readout values from the active pixels to compensate for the unwanted effects.
1. A method of driving a pixel circuit in a video display having an array of pixel circuits, the pixel circuit including an organic light emitting device, the method comprising:
defining a compressed range of source driver voltage for the pixel circuit, the compressed range of source driver voltage a subset of an available voltage range of a source driver for driving the pixel circuit;
adjusting the compressed range of source driver voltage for the pixel circuit based on an aging of the pixel circuit; and
driving the pixel circuit according to a target luminance using the compressed range of source driver voltage.
2. The method of claim 1 , wherein driving the pixel circuit comprises using a non-linear gamma over the compressed range of source driver voltage to drive the pixel circuit according to the target luminance.
3. The method of claim 1 , wherein driving the pixel circuit comprises using a non-linear gamma over part of the compressed range of source driver voltage to drive the pixel circuit according to the target luminance and using a linear gamma over a different part of the compressed range of source driver voltage to drive the pixel circuit according to the target luminance.
4. The method of claim 1 , wherein adjusting the compressed range of source driver voltage comprises shifting the compressed range of source driver voltage up or down.
5. The method of claim 4 , wherein the compressed range of source driver voltage is shifted up or down to obtain a desired black level after said aging.
6. The method of claim 4 , wherein the compressed range of source driver voltage is shifted up or down to obtain a desired peak brightness after said aging.
7. The method of claim 1 , further comprising configuring reference voltages of the source driver such that a scale of bits applies to the compressed range of source driver voltage.
8. A display system comprising:
an array of pixel circuits arranged on a panel, each of the pixel circuits including an organic light emitting device, and
a source driver for driving each of the pixel circuits according to a target luminance using a compressed range of source driver voltage for the pixel circuit defined as a subset of an available voltage range of the source driver for driving the pixel circuit, wherein the compressed range of source driver voltage for the pixel circuit is adjusted based on an aging of the display.
9. The display of claim 8 , wherein the source driver drives the pixel circuit according a non-linear gamma over the compressed range of source driver voltage to drive the pixel circuit according to the target luminance.
10. The display of claim 8 , wherein the source driver drives the pixel circuit according a non-linear gamma over part of the compressed range of source driver voltage to drive the pixel circuit according to the target luminance and according to a linear gamma over a different part of the compressed range of source driver voltage to drive the pixel circuit according to the target luminance.
11. The display of claim 8 , wherein the compressed range of source driver voltage is adjusted by shifting the compressed range of source driver voltage up or down.
12. The display of claim 11 , wherein the compressed range of source driver voltage is shifted up or down to obtain a desired black level after said aging.
13. The display of claim 11 , wherein the compressed range of source driver voltage is shifted up or down to obtain a desired peak brightness after said aging.
14. The display of claim 8 , wherein reference voltages of the source driver are configured such that a scale of bits applies to the compressed range of source driver voltage.