Voltage-programming scheme for current-driven AMOLED displays
First Claim
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1. A system for programming at least one pixel circuit in a display, the system comprising:
- a voltage driver for generating a current or 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 current or 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 current or 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.
564 Citations
70 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 current or 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 current or 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 current or 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 adjusting a programming value for a pixel circuit in an OLED display to compensate for degradation of the display or for non-uniformity and degradation of the display, the method comprising:
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applying a charge to the pixel circuit to acquire threshold voltage information or a shift in threshold voltage information from the pixel circuit; responsive to applying the charge, measuring a voltage of the pixel circuit; extracting from the measured voltage a degradation of the pixel circuit, the degradation adversely affecting a programmed brightness of an OLED in the pixel circuit; digitizing the extracted degradation of the pixel circuit to a digital compensation value representing the degradation of the pixel circuit; and adjusting a video input signal to the pixel circuit based on the digital compensation value to compensate for the degradation of the pixel circuit, wherein the extracting the degradation includes extracting a threshold voltage or a shift in the threshold voltage of a drive transistor in the pixel circuit. - View Dependent Claims (32, 33, 34, 35)
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36. A method of adjusting a programming value for a pixel circuit in an OLED display to compensate for degradation or non-uniformity of the display or for non-uniformity and degradation of the display, the method comprising:
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applying a current to a node of a pixel circuit; responsive to the applying, acquiring a voltage from the node; creating, from the acquired voltage, a compensation value; storing the compensation value in a memory device; and correcting a video input signal applied to the pixel circuit based on the stored compensation value, wherein the compensation value is indicative of a threshold voltage or a shift in the threshold voltage of a drive transistor in the pixel circuit. - View Dependent Claims (37, 38, 39, 40)
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41. A system for driving a display panel including a pixel circuit having a plurality of transistors and an organic light emitting device, the system comprising:
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a driver for generating a programming voltage or current to program the pixel circuit through a data line coupled to the pixel circuit; a switching network connected to the display panel; a measurement unit connected to the switching network and shared among multiple columns of the display panel, the measurement unit converting an analog measurement from a data node of corresponding pixel circuits in the multiple columns to a digitalized value; and a memory device configured to store the digital values converted by the measurement unit. - View Dependent Claims (42)
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43. A method of extracting different parameters from a pixel circuit in a display panel, comprising:
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extracting, using a first measurement implementation, from the pixel circuit a first parameter indicative of a degradation or non-uniformity of the pixel circuit; extracting, using a second measurement implementation different from the first measurement implementation, from the pixel circuit a second parameter indicative of the same or a different degradation or non-uniformity of the pixel circuit as the first extracted parameter; and driving the pixel circuit with programming information that is adjusted based on the extracted first parameter or the extracted second parameter or both, wherein the first parameter is related to a threshold voltage of a drive transistor in the pixel circuit. - View Dependent Claims (44)
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45. A method of adjusting a programming value for a pixel circuit in an OLED display to compensate for degradation of the display or for non-uniformity and degradation of the display, the method comprising:
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applying a charge to the pixel circuit to acquire threshold voltage information or a shift in threshold voltage information from the pixel circuit; responsive to applying the charge, measuring a voltage of the pixel circuit; extracting from the measured voltage a degradation of the pixel circuit, the degradation adversely affecting a programmed brightness of an OLED in the pixel circuit; digitizing the extracted degradation of the pixel circuit to a digital compensation value representing the degradation of the pixel circuit; and adjusting a video input signal to the pixel circuit based on the digital compensation value to compensate for the degradation of the pixel circuit, wherein the extracting the degradation includes measuring a voltage remaining on a data node of the pixel circuit during a threshold voltage acquisition. - View Dependent Claims (46, 47, 48)
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49. A method of adjusting a programming value for a pixel circuit in an OLED display to compensate for degradation of the display or for non-uniformity and degradation of the display, the method comprising:
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applying a charge to the pixel circuit to acquire threshold voltage information or a shift in threshold voltage information from the pixel circuit; responsive to applying the charge, measuring a voltage of the pixel circuit; extracting from the measured voltage a degradation of the pixel circuit, the degradation adversely affecting a programmed brightness of an OLED in the pixel circuit; digitizing the extracted degradation of the pixel circuit to a digital compensation value representing the degradation of the pixel circuit; and adjusting a video input signal to the pixel circuit based on the digital compensation value to compensate for the degradation of the pixel circuit, wherein the extracting the degradation includes measuring a rate of discharge of a voltage on the data node of the pixel circuit. - View Dependent Claims (50, 51)
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52. A method of adjusting a programming value for a pixel circuit in an OLED display to compensate for degradation of the display or for non-uniformity and degradation of the display, the method comprising:
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applying a charge to the pixel circuit to acquire threshold voltage information or a shift in threshold voltage information from the pixel circuit; responsive to applying the charge, measuring a voltage of the pixel circuit; extracting from the measured voltage a degradation of the pixel circuit, the degradation adversely affecting a programmed brightness of an OLED in the pixel circuit; digitizing the extracted degradation of the pixel circuit to a digital compensation value representing the degradation of the pixel circuit; and adjusting a video input signal to the pixel circuit based on the digital compensation value to compensate for the degradation of the pixel circuit, wherein the digitizing the extracted degradation includes; storing digital data corresponding to the digitized extracted degradation in a memory; adding the digital data to the programming value to produce a resulting voltage; and converting the resulting voltage to a corresponding analog value to be applied as the video input signal during a programming phase. - View Dependent Claims (53, 54, 55, 56)
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57. A method of adjusting a programming value for a pixel circuit in an OLED display to compensate for degradation of the display or for non-uniformity and degradation of the display, the method comprising:
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applying a charge to the pixel circuit to acquire threshold voltage information or a shift in threshold voltage information from the pixel circuit; responsive to applying the charge, measuring a voltage of the pixel circuit; extracting from the measured voltage a degradation of the pixel circuit, the degradation adversely affecting a programmed brightness of an OLED in the pixel circuit; digitizing the extracted degradation of the pixel circuit to a digital compensation value representing the degradation of the pixel circuit; and adjusting a video input signal to the pixel circuit based on the digital compensation value to compensate for the degradation of the pixel circuit, wherein the adjusted video signal input is applied to the pixel circuit during a programming phase as a current or a voltage. - View Dependent Claims (58, 59, 60, 61, 62, 63)
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64. A method of adjusting a programming value for a pixel circuit in an OLED display to compensate for degradation or non-uniformity of the display or for non-uniformity and degradation of the display, the method comprising:
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applying a current to a node of a pixel circuit; responsive to the applying, acquiring a voltage from the node; creating, from the acquired voltage, a compensation value; storing the compensation value in a memory device; and correcting a video input signal applied to the pixel circuit based on the stored compensation value, wherein the voltage acquired from the data node corresponds to a threshold voltage or a shift in the threshold voltage of a drive transistor in the pixel circuit. - View Dependent Claims (65, 66, 67)
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68. A method of extracting different parameters from a pixel circuit in a display panel, comprising:
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extracting, using a first measurement implementation, from the pixel circuit a first parameter indicative of a degradation or non-uniformity of the pixel circuit; extracting, using a second measurement implementation different from the first measurement implementation, from the pixel circuit a second parameter indicative of the same or a different degradation or non-uniformity of the pixel circuit as the first extracted parameter; and driving the pixel circuit with programming information that is adjusted based on the extracted first parameter or the extracted second parameter or both, wherein the second parameter is a current through a common electrode of an organic light emitting device in the pixel circuit, wherein the common electrode is connected to all of the organic light emitting devices in the display panel.
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69. The method of claim 84, wherein the first parameter is related to a threshold voltage of a drive transistor in the pixel circuit.
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70. A method of adjusting a programming value for a pixel circuit in an OLED display to compensate for degradation of the display or for non-uniformity and degradation of the display, the method comprising:
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applying a charge to the pixel circuit to acquire threshold voltage information or a shift in threshold voltage information from the pixel circuit; responsive to applying the charge, measuring a voltage of the pixel circuit; extracting from the measured voltage a degradation of the pixel circuit, the degradation adversely affecting a programmed brightness of an OLED in the pixel circuit; digitizing the extracted degradation of the pixel circuit to a digital compensation value representing the degradation of the pixel circuit; adjusting a video input signal to the pixel circuit based on the digital compensation value to compensate for the degradation of the pixel circuit; generating a voltage versus current relationship for the pixel circuit based on current values applied to a data node of the pixel circuit and based on voltages sampled at the data node; and extracting, based on the generated voltage versus current relationship, a voltage corresponding to a zero current level, wherein the digital compensation value is further adjusted based on the extracted voltage.
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Specification