Adaptive Gamma Reference Voltage Generator for Stable OLED Luminance
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Solution Overview
Problem
In OLED displays, maintaining a consistent voltage difference between the power source voltage and the source output signal is crucial to avoid luminance deviations across the display panel, which existing technologies have not adequately addressed.
Innovation Solution
A gamma reference voltage generator with a voltage difference generating circuit, selection voltage generating circuit, and voltage calculating circuit to generate and adjust gamma reference voltages based on power source voltage levels, ensuring a stable voltage difference for consistent luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the power source voltage varies, then the emission current of OLED changes, but the luminance consistency across the display panel deteriorates
Solution Approach 1:
The patent dynamically adjusts the gamma reference voltage based on the detected power source voltage level. When the power source voltage varies, the system changes the parameter (gamma reference voltage) to maintain a consistent voltage difference, thereby keeping the emission current and luminance consistent across the display panel.
Solution Approach 2:
The patent employs a feedback mechanism where the actual power source voltage is detected and compared with a reference voltage. Based on this comparison, the gamma reference voltage is adjusted to maintain the desired voltage difference, ensuring stable emission current and luminance consistency despite power source voltage variations.
2Illumination intensity
If a complex voltage regulation circuit is used to maintain voltage difference, then luminance consistency improves, but circuit area and production cost increase
Solution Approach 1:
The patent integrates multiple functions into a single gamma reference voltage generator circuit. This circuit simultaneously performs voltage detection, comparison, and adjustment functions, eliminating the need for separate complex voltage regulation circuits while maintaining luminance consistency.
Solution Approach 2:
The gamma reference voltage generator automatically detects power source voltage variations and adjusts its own output voltage accordingly. This self-regulating mechanism eliminates the need for external complex voltage regulation circuits, reducing circuit area while maintaining voltage difference stability.
3Device complexity
If traditional gamma voltage generation is used, then circuit simplicity is maintained, but power consumption increases due to voltage variations
Solution Approach 1:
The patent dynamically changes the gamma reference voltage parameter based on power source voltage levels to optimize power consumption. By adjusting the voltage to match actual power source conditions, the system maintains circuit simplicity while minimizing unnecessary power consumption that would occur with fixed voltage generation.
Data Source
AI summary
A gamma reference voltage generator includes a voltage difference generating circuit, a selection voltage generating circuit and a voltage calculating circuit. The voltage difference generating circuit generates a first voltage difference and a second voltage difference. The selection voltage generating circuit generates an initial voltage and receives a power source voltage and selectively outputs the initial voltage or the power source voltage as a selection voltage according to a voltage level of the power source voltage. The voltage calculating circuit receives the selection voltage, the first voltage difference and the second voltage difference and correspondingly output a first gamma reference voltage and a second gamma reference voltage, in which the first gamma reference voltage is a sum of the selection voltage and the first voltage difference, and the second gamma reference voltage is a difference between the selection voltage and the second voltage difference.