Gamma Reference Voltage Generator Black Candidate Selection
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Solution Overview
Problem
Display technologies face issues with grayscale correction, where luminance does not reach desired levels due to image overlap or color sticking, and current leakage between color pixel channels, leading to distortion or failure in displaying single color low grayscale images.
Innovation Solution
A gamma reference voltage generator that selectively generates a black grayscale voltage using a first resistor string, black voltage setters, a selector, and gamma voltage setters, based on a black level command signal, to enhance display quality by properly selecting black gamma voltage and gamma voltages for the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single black grayscale voltage is used for grayscale correction, then the circuit design is simple, but the luminance cannot reach desired levels due to image overlap or color sticking
Solution Approach 1:
The patent segments the black grayscale voltage into multiple candidate voltages (first black candidate voltage, second black candidate voltage, etc.) extracted from a resistor string. Instead of using a single fixed voltage, the system provides multiple segmented voltage options that can be selected based on display conditions, thereby achieving desired luminance levels while maintaining manageable circuit complexity through systematic voltage division.
Solution Approach 2:
The patent implements dynamic selection of black candidate voltages based on grayscale values. The selector dynamically chooses between first, second, and third black candidate voltages depending on the input grayscale value range. This dynamic adaptation allows the system to optimize luminance output for different display conditions, resolving the contradiction between fixed simple design and variable performance requirements.
2Ease of operation
If a fixed black gamma voltage is applied, then the circuit operation is simple, but current leakage occurs between color pixel channels causing distortion
Solution Approach 1:
The patent employs dynamic selection of black candidate voltages based on grayscale value ranges. For different grayscale ranges (e.g., 0-63, 64-127, 128-255), the selector dynamically chooses appropriate voltages from the candidate set. This dynamic operation prevents current leakage between color channels by adapting the voltage level to match the specific display conditions, thereby maintaining both operational simplicity and display reliability.
Solution Approach 2:
The patent changes the voltage parameter dynamically based on grayscale values. By adjusting which black candidate voltage is selected (first, second, or third) according to the grayscale range, the system modifies the electrical parameter to prevent current leakage. This parameter adaptation maintains circuit operation simplicity while ensuring reliable, distortion-free image display across different grayscale conditions.
3Manufacturing precision
If multiple black candidate voltages are provided and selected based on grayscale values, then display quality is improved, but the device complexity increases
Solution Approach 1:
The patent segments the voltage generation into a systematic structure using a resistor string with multiple taps, where each tap provides a specific black candidate voltage. This segmentation approach achieves precise grayscale correction by providing dedicated voltage options for different grayscale ranges, while the modular resistor-based structure keeps the implementation complexity manageable through regular, predictable circuit patterns.
4Adaptability or versatility
If black level command signal is used to generate selection signal, then adaptability to different display conditions is improved, but the control system complexity increases
Solution Approach 1:
The patent changes the control approach by using the black level command signal parameter to directly determine voltage selection. The black level command signal (representing values 0-3) directly maps to selection of first, second, or third black candidate voltages. This parameter-based control provides adaptability to different display conditions while maintaining relatively simple control logic through direct parameter mapping rather than complex processing.
Data Source
AI summary
A gamma reference voltage generator includes a first resistor string, black voltage setters, a selector, and a second resistor string. The first resistor string receives a first reference voltage and a second reference voltage. The black voltage setters extract a plurality of black candidate voltages from the first resistor string. The selector selects one of the black candidate voltages as a black gamma voltage based on a selection signal. The second resistor string receives a first voltage corresponding to one of the black candidate voltages and a second voltage extracted from the first resistor string. In addition, the gamma reference voltage generator includes gamma voltage setters that extract a plurality of gamma voltages from the second resistor string.