Gamma Amplifier Offset Polarity Inversion for Display Luminance
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Solution Overview
Problem
Display panel quality is deteriorated due to offset voltage issues in gamma amplifiers, where positive or negative offset values lead to discrepancies in output voltage, affecting the display's target voltage and luminance.
Innovation Solution
The polarity of the offset voltage of the gamma amplifier is alternately inverted in units of one frame, two frames, one horizontal line, two horizontal lines, or four horizontal lines to spatially and temporally compensate for the offset voltage, ensuring the output voltage aligns with the target voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gamma amplifier operates with a fixed offset voltage polarity, then the circuit design is simple, but the output voltage deviates from the target voltage and display quality deteriorates
Solution Approach 1:
The patent applies periodic action by alternately inverting the offset voltage polarity in units of one frame or two frames. This periodic inversion causes the offset voltage to cancel out over time, effectively compensating for the voltage deviation without requiring complex correction circuits. The gamma amplifier continues to operate with the same simple circuit design, but the periodic polarity inversion achieves precise output voltage control.
Solution Approach 2:
The patent introduces dynamics by making the offset voltage polarity time-dependent rather than fixed. The polarity is dynamically inverted according to a predetermined pattern (one frame inversion or two frame inversion), transforming the static offset voltage into a dynamic compensation mechanism that adapts to the display refresh rate and maintains accurate output voltage throughout the display cycle.
2Reliability
If the offset voltage polarity is inverted in a unit of one frame, then temporal compensation is effective, but flicker effects may occur in the display
Solution Approach 1:
The patent uses periodic action with two different periods: one frame inversion for temporal compensation and two frame inversion to reduce flicker. By alternating between these two periodic inversion patterns, the system achieves reliable offset voltage compensation while minimizing visible flicker effects in the display. The dual-periodic approach allows the offset to cancel effectively without creating noticeable display artifacts.
3Speed
If the data voltage polarity is inverted in a unit of one frame, then the display updates quickly, but the offset voltage compensation is less effective
Solution Approach 1:
The patent applies periodic action by coordinating the data voltage inversion with the offset voltage polarity inversion. Both are inverted in sync (one frame inversion together, or two frame inversion together), creating a harmonious timing relationship that maintains fast display updates while ensuring effective offset compensation. This synchronized periodic inversion ensures that the gamma amplifier output remains accurate throughout the display refresh cycle.
Data Source
AI summary
A display apparatus includes a display panel, a gamma reference voltage generator and a data driver. The gamma reference voltage generator is configured to generate a gamma reference voltage. The gamma reference voltage includes a gamma amplifier configured to output the gamma reference voltage. The data driver is configured to generate a data voltage based on the gamma reference voltage and to output the data voltage to the display panel. A polarity of an offset voltage of the gamma amplifier is inverted alternately in a unit of one frame and in a unit of two frames.