Voltage-programming scheme for current-driven AMOLED displays
First Claim
Patent Images
1. A system for programming at least one pixel circuit in a display, the system comprising:
- a voltage driver for generating a voltage to apply to a data node of the at least one pixel circuit to thereby program the at least one pixel circuit according to the generated voltage;
a programmable current source for providing a first current and a second current to apply to the data node of the at least one pixel circuit;
a sampler for reading a first voltage on the data node while the first current is maintained through the at least one pixel circuit via the programmable current source and for reading a second voltage on the data node while the second current is maintained through the at least one pixel circuit via the programmable current source; and
a controller configured to;
generate a voltage versus current relationship for the at least one pixel circuit based on the first current and the second current and based on the sampled first and second voltages,extract, based on the voltage versus current relationship for the at least one pixel circuit, a voltage corresponding to a zero current level, andprogram the at least one pixel circuit via the data node with a programming voltage generated by the voltage driver that is set according to display data and according to the extracted voltage corresponding to the zero current level.
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Abstract
A system and method for driving an AMOLED display is provided. The AMOLED display includes a plurality of pixel circuits. A voltage-programming scheme, a current-programming scheme or a combination thereof is applied to drive the display. Threshold shift information, and/or voltage necessary to obtain hybrid driving circuit may be acquired. A data sampling may be implemented to acquire a current/voltage relationship. A feedback operation may be implemented to correct the brightness of the pixel.
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Citations
35 Claims
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1. A system for programming at least one pixel circuit in a display, the system comprising:
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a voltage driver for generating a voltage to apply to a data node of the at least one pixel circuit to thereby program the at least one pixel circuit according to the generated voltage; a programmable current source for providing a first current and a second current to apply to the data node of the at least one pixel circuit; a sampler for reading a first voltage on the data node while the first current is maintained through the at least one pixel circuit via the programmable current source and for reading a second voltage on the data node while the second current is maintained through the at least one pixel circuit via the programmable current source; and a controller configured to; generate a voltage versus current relationship for the at least one pixel circuit based on the first current and the second current and based on the sampled first and second voltages, extract, based on the voltage versus current relationship for the at least one pixel circuit, a voltage corresponding to a zero current level, and program the at least one pixel circuit via the data node with a programming voltage generated by the voltage driver that is set according to display data and according to the extracted voltage corresponding to the zero current level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of operating a display having at least one pixel circuit, the at least one pixel circuit having a light emitting device coupled in series with a driving transistor configured to convey a driving current through the light emitting device according to display information, the at least one pixel circuit configured to be alternately programmed according to the display information by a programming current applied to a data node of the at least one pixel circuit or by a programming voltage applied to the data node, the method comprising:
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applying a first current to the data node of the at least one pixel circuit; reading a first voltage on the data node while the first current is maintained through the at least one pixel circuit; applying a second current to the data node of the at least one pixel circuit; reading a second voltage on the data node while the second current is maintained through the at least one pixel circuit; storing digital information indicative of the first and second voltages such that the first and second voltages are associated with the first and second currents; generating a voltage versus current relationship for the at least one pixel circuit based on the first and second voltages and the first and second currents; extracting, based on the generated voltage versus current relationship for the at least one pixel circuit, a voltage corresponding to a zero current level; and programming the at least one pixel circuit by applying, to the data node of the at least one pixel circuit, a programming voltage that is based on the display data and the voltage corresponding to the zero current level. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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21. A system for programming at least one pixel circuit in a display, the system comprising:
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a voltage driver for generating a voltage to apply to a data node of the at least one pixel circuit to thereby program the at least one pixel circuit according to the generated voltage; a programmable current source for providing a first current to apply to the data node of the at least one pixel circuit; a sampler for reading a first voltage on the data node while the first current is maintained through the at least one pixel circuit via the programmable current source; and a controller configured to; receive calibration data indicative of a voltage versus current relationship for the at least one pixel circuit; generate an updated voltage versus current relationship for the at least one pixel circuit based on the first current and the first voltage and based on the received calibration data, extract, based on the updated voltage versus current relationship for the at least one pixel circuit, a voltage corresponding to a zero current level, and program the at least one pixel circuit via the data node with a programming voltage generated by the voltage driver that is set according to display data and according to the extracted voltage corresponding to the zero current level. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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28. A method of operating a display having at least one pixel circuit, the at least one pixel circuit having a light emitting device coupled in series with a driving transistor configured to convey a driving current through the light emitting device according to display information, the at least one pixel circuit configured to be alternately programmed according to the display information by a programming current applied to a data node of the at least one pixel circuit or by a programming voltage applied to the data node, the method comprising:
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applying a first current to the data node of the at least one pixel circuit; reading a first voltage on the data node while the first current is maintained through the at least one pixel circuit; storing digital information indicative of the first voltage such that the first voltage is associated with the first current; receiving calibration data indicative of a voltage versus current relationship for the at least one pixel circuit; generating an updated voltage versus current relationship for the at least one pixel circuit based on the first voltage, the first current, and the received calibration data; extracting, based on the updated voltage versus current relationship for the at least one pixel circuit, a voltage corresponding to a zero current level; and programming the at least one pixel circuit by applying, to the data node of the at least one pixel circuit, a programming voltage that is based on the display data and the voltage corresponding to the zero current level. - View Dependent Claims (29, 30)
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31. A method of calibrating a display panel having a plurality of pixel circuits, each of the pixel circuits including a drive transistor coupled to an organic light emitting device, comprising:
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measuring a degradation of each pixel circuit of a subset of the pixel circuits during a frame while displaying a video image with the pixel circuits on the display panel; extracting, for each of the pixel circuits of the subset, a current/voltage point for the pixel circuit from the degradation measurement; determining, for each of the pixel circuits of the subset, corresponding compensation information from a fitting of a previously stored voltage versus current relationship for the pixel circuit to the extracted current/voltage point for the pixel circuit; and compensating each of the pixel circuits of the subset based on the respective compensation information for each of the pixel circuits of the subset. - View Dependent Claims (32, 33, 34, 35)
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Specification