Gamma Voltage Divider Circuit for Low Gray-Level Accuracy
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Solution Overview
Problem
Existing Gamma voltage divider circuits in OLED and LCD display devices suffer from low accuracy in voltage division, leading to indistinguishable gray levels and increased complexity and cost due to the large number of resistors required.
Innovation Solution
A Gamma voltage divider circuit with at least two gray-level resistor strings connected in series, where a gray-level threshold voltage is inputted to a common terminal, optimizing the accuracy of low gray-level voltages and reducing the number of resistors needed by adjusting the mapping of band point voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of voltage dividing resistors are used in the Gamma voltage divider circuit, then the voltage division accuracy is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent divides the resistor string into multiple segments with different resistance values. Specifically, it uses a first resistor string with resistance R1 for high gray levels and a second resistor string with resistance R2 for low gray levels, where R2 < R1. This segmentation allows the circuit to achieve high voltage division accuracy for low gray levels without requiring an excessively long single resistor string, thereby reducing overall device complexity.
Solution Approach 2:
The patent applies different resistance values to different segments of the resistor string based on the specific requirements of different gray level ranges. The first resistor string uses a larger resistance value for high gray levels where larger voltage steps are acceptable, while the second resistor string uses a smaller resistance value for low gray levels where fine voltage differentiation is critical. This local optimization achieves high measurement precision where needed without proportionally increasing overall complexity.
2Measurement precision
If a large number of voltage dividing resistors are used in the Gamma voltage divider circuit, then the voltage division accuracy is improved, but the manufacturing cost increases
Solution Approach 1:
The patent segments the resistor string into multiple parts with different resistance values, which allows achieving high voltage division accuracy for low gray levels without using an excessively large number of resistors. This reduces the total component count and associated manufacturing costs while maintaining the required precision.
Solution Approach 2:
The patent changes the resistance parameter along the resistor string, using different resistance values (R1 and R2) for different segments. This parameter variation allows the circuit to achieve high accuracy where needed (low gray levels) while using fewer total resistors, thereby reducing manufacturing cost.
3Reliability
If the gray-level band point voltages are adjusted sequentially to satisfy gamma relations, then the display quality is improved, but the adjustment time and complexity increase
Solution Approach 1:
The patent divides the gray level range into segments (high gray levels and low gray levels) with different resistance values. This segmentation allows for more efficient voltage distribution and reduces the number of adjustment steps needed to achieve gamma compliance, thereby reducing adjustment time while maintaining display quality.
Solution Approach 2:
The patent optimizes the resistance parameters of different resistor segments to directly achieve the desired voltage distribution for gamma relations. By pre-configuring appropriate resistance values (R1 and R2) for different gray level ranges, the system reduces the iterative adjustment time while ensuring display quality meets gamma standards.
Data Source
AI summary
A Gamma voltage divider circuit, a voltage adjusting method, and a liquid crystal display device are proposed. Compared to the arrangement of voltage dividing resistor string of the existing Gamma voltage divider circuit, by changing the mapping of band point voltages, the application can optimize accuracy of low gray-level voltages in a further step, improve the display effect, and at the same time, reduce the number of voltage dividing resistors and lower the complexity and cost of the Gamma voltage divider circuit. The Gamma voltage divider circuit is adaptable to the voltage dividing resistor string settings of OLED display panels as well as LCD panels.