Display Compensation Circuit for Gray-Level Voltage Drop Correction
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Solution Overview
Problem
Existing compensation circuits in organic light-emitting display devices struggle to accurately compensate for voltage drops in pixel driving voltages due to variable resistor values, leading to overcompensation or undercompensation across different gray levels, affecting luminance and power consumption.
Innovation Solution
A compensation circuit that calculates voltage drop amounts using voltages at two points in the wire, employing gain and voltage compensators to generate optimized gamma reference voltages, adjusting based on derived mathematical equations to match the position of pixel feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed gain value is used in the compensation circuit, then the circuit structure is simple, but the compensation accuracy deteriorates for different gray levels
Solution Approach 1:
The patent applies dynamics by making the gain value adjustable rather than fixed. The gain compensator circuit can change the gain value dynamically based on the feedback voltage level corresponding to different gray levels, allowing the compensation circuit to adapt to varying voltage drop conditions across different display intensities.
Solution Approach 2:
The patent changes the parameter of gain value from a constant to a variable parameter. By adjusting the gain value according to the feedback voltage (which represents different gray levels), the system optimizes compensation accuracy for each gray level while maintaining a relatively simple circuit structure.
2Adaptability or versatility
If the pixel resistance value changes based on image data, then the display can show different gray levels, but the voltage drop compensation becomes inaccurate
Solution Approach 1:
The patent uses feedback by taking the pixel driving voltage after it passes through the pixel and feeding it back to the compensation circuit. This feedback voltage contains information about the actual voltage drop, which is then used to calculate and compensate for the voltage drop amount, improving measurement accuracy despite varying pixel resistance.
Solution Approach 2:
The patent adjusts the gain value parameter based on the feedback voltage level, which corresponds to different gray levels and pixel resistance values. This dynamic parameter adjustment allows the system to maintain accurate compensation across varying display conditions.
3Device complexity
If a single feedback position is used for voltage compensation, then the circuit is simple, but compensation accuracy varies across different gray levels
Solution Approach 1:
The patent applies local quality by optimizing the compensation for each specific condition (gray level) rather than using a uniform approach. The gain compensator circuit adjusts the gain value locally for each feedback voltage level, ensuring high compensation accuracy for each gray level while maintaining a relatively simple single feedback position configuration.
Data Source
AI summary
A compensation circuit and a display device are disclosed. The compensation circuit includes a gain compensator that calculates a voltage drop amount using a first pixel driving voltage output from a power supply and a second pixel driving voltage fed back from a wire of a display panel. The voltage drop amount is amplified by a predetermined gain value. A first voltage compensator generates a high-potential gamma reference voltage by adjusting a first reference voltage using the voltage drop amount and a second voltage compensator generates a low potential gamma reference voltage by adjusting a second reference voltage using the generated voltage drop. The gain value is a value calculated using voltages at two predetermined points within the wire of the display panel. Accordingly, an individual compensation circuit optimized depending on a position where the pixel driving voltage is fed back can be provided.