Back to results
US 8,912,990 B2Granted
Display having a transistor-degradation circuit
AssigneeApple Inc.
InventorsCarlin Vieri, Ahmad Al-Dahle, Yongman Lee, Wei Yao
Life of this patent
Estimating the term…
Abstract
Systems, methods, and devices are disclosed, including a device having a liquid-crystal display (LCD) panel that includes a transistor-degradation circuit. In some embodiments, the transistor-degradation circuit is configured to output a signal indicative of a change in a property of a transistor on the LCD panel over time.
Claims50
A method, comprising:
- aging a transistor on a liquid crystal display (LCD) panel, while leaving a control transistor substantially idle;
- and
- comparing a threshold voltage of the aged transistor to an estimate of an initial threshold voltage of the aged transistor, via a threshold voltage of the control transistor, to estimate a change in the threshold voltage of the aged transistor, wherein the threshold voltage for the aged transistor comprises a first gate voltage above which the aged transistor becomes conductive and the threshold voltage for the control transistor comprises a second gate voltage above which the control transistor becomes conductive.
A device, comprising:
- a liquid crystal display (LCD) panel comprising a plurality of gate-line transistors;
- a transistor-degradation circuit formed on the LCD panel, wherein the transistor-degradation circuit comprises a control transistor, and wherein a support circuit is configured to keep the control transistor off during a substantial portion of the time in which the LCD panel is operating and configured to turn the control transistor on to compare a threshold voltage of the control transistor to a threshold voltage of a second transistor;
- a driver integrated circuit coupled to the LCD panel;
- and
- the support circuit disposed on the driver integrated circuit and in communication with the transistor-degradation circuit.
2 more elements
A device, comprising:
- a liquid crystal display (LCD) panel comprising a first plurality of transistors;
- a transistor-degradation circuit disposed on the LCD panel and comprising a second plurality of transistors generally having a same electrical properties as the first plurality of transistors, wherein the transistor-degradation circuit is configured to estimate a change in threshold voltages for the first plurality of transistors over time based on a comparison of threshold voltages for the second plurality of transistors with initial threshold voltages for the second plurality of transistors, wherein the threshold voltages for the first plurality of transistors comprises a first gate voltage above which the first plurality of transistors becomes conductive and the threshold voltages for the second plurality of transistors comprises a second gate voltage above which the second plurality of transistors becomes conductive;
- a driver IC coupled to the LCD panel;
- and
- a support circuit formed within the driver IC, wherein the support circuit is coupled to the transistor-degradation circuit by fewer than three signal paths.
2 more elements
A method, comprising:
- measuring a property of a first transistor by conducting a first current through the first transistor and a signal path during only a first portion of a clock cycle;
- measuring the property of a second transistor by conducting a second current through the second transistor and the signal path during only a second portion of the clock cycle;
- and
- adjusting a parameter of a liquid crystal display (LCD) panel based, at least in part, on a comparison of the property of the first transistor and the property of the second transistor.
1 more element
A device, comprising:
- a liquid-crystal display (LCD) panel comprising a transistor-degradation circuit, wherein the transistor-degradation circuit is configured to output a signal corresponding to a difference between a threshold voltage of an aged transistor and a threshold voltage of a control transistor that is substantially unaged to indicate a change in threshold voltage of the aged transistor, wherein the threshold voltage of the control transistor corresponds with an initial threshold voltage of the aged transistor before it is aged, the threshold voltage for the aged transistor comprises a first gate voltage above which the aged transistor becomes conductive, and the threshold voltage for the control transistor comprises a second gate voltage above which the control transistor becomes conductive.
Dependencies are inferred from the claim text.