Display Pixel Body-Voltage Compensation Against UV Luminance Shift
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Solution Overview
Problem
The accumulation of charges on the substrate of a display device due to external ultraviolet light causes a negative bias on the transistor body, leading to a shift in the threshold voltage and resulting in luminance deviation and deteriorated image quality.
Innovation Solution
The pixel design includes a body capacitor and body transistor connected between the second terminal and the body of the driving transistor, compensating for the body voltage of the driving transistor, thereby reducing luminance deviation and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If charges are accumulated on the substrate due to ultraviolet light, then the transistor body experiences negative bias, but the threshold voltage shifts causing luminance deviation
Solution Approach 1:
The body capacitor is pre-charged to a first voltage level before the pixel operates. When ultraviolet light causes charge accumulation and negative bias on the transistor body, the body capacitor compensates by maintaining the body potential, preventing threshold voltage shifts. This preliminary preparation of the capacitor resolves the contradiction by proactively counteracting the harmful effect before it degrades image quality.
2Manufacturing precision
If a body capacitor and body transistor are added to compensate body voltage, then luminance deviation is reduced, but device complexity increases
Solution Approach 1:
The body capacitor serves multiple functions: it compensates for body voltage shifts due to ultraviolet light, maintains transistor threshold voltage stability, and prevents luminance deviation. By making the capacitor multi-functional, the patent reduces the need for additional separate compensation circuits, thereby limiting the increase in device complexity while achieving the desired threshold voltage stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The compensation of the body voltage in the driving transistor reduces luminance deviation and enhances the image quality of the display device by stabilizing the threshold voltage.
Implementation Method 1
a body capacitor which includes a first terminal connected to the body of the driving transistor and a second terminal
Data Source
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AI summary
A pixel includes a light-emitting element which emits light based on a driving current and includes a first electrode and a second electrode which receives a low power voltage, a driving transistor which generates the driving current and includes a gate connected to a first node, a first terminal connected to a second node, a second terminal connected to a third node, and a body, a body capacitor which includes a first terminal connected to the body of the driving transistor and a second terminal, and a body transistor which includes a gate which receives a body gate signal, a first terminal connected to the second terminal of the body capacitor, and a second terminal connected to the third node.