Gamma Voltage Output Circuit with Segmented Resistor Strings
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Solution Overview
Problem
Existing gamma voltage output circuits for liquid crystal displays are inefficient in adjusting gamma voltages for different external environments, requiring numerous resistors and affecting multiple gamma voltages when one resistor is adjusted, leading to suboptimal display performance across varying conditions.
Innovation Solution
A gamma voltage output circuit with internal and external resistor strings and switching circuits allows for independent adjustment of gamma voltages by parallel connecting resistors between the internal and external strings, enabling flexible gamma curve adjustments without altering the internal IC configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple resistor strings are used to provide different gamma curves for different external environments, then the display can adapt to different environments, but the number of resistors increases significantly
Solution Approach 1:
The patent divides the gamma voltage adjustment function into two independent parts: internal resistor strings (R1-R14) integrated in the driving IC and external resistor strings (R1'-R14') connected externally. This segmentation allows the internal IC to remain simple while the external resistors provide the necessary gamma curve variations for different environments.
Solution Approach 2:
The patent moves the gamma adjustment capability from the internal IC dimension to the external connection dimension. By placing resistor strings outside the IC and using switching circuits for parallel connection, the system gains gamma curve adaptability without increasing internal IC complexity or resistor count.
2Manufacturing precision
If the resistance value of a resistor is adjusted to change gamma voltage, then the gamma curve can be optimized, but other gamma voltages are also affected
Solution Approach 1:
The patent segments the gamma voltage generation into multiple independent resistor strings (internal R1-R14 and external R1'-R14'). Each resistor can be independently adjusted or switched without affecting others, allowing precise control of individual gamma voltages while maintaining overall gamma curve accuracy.
Solution Approach 2:
The patent introduces switching circuits that dynamically connect or disconnect external resistors in parallel with internal resistors based on different gamma curve requirements. This dynamic configuration allows the system to switch between different gamma curves without physically changing resistors, maintaining precision while enabling independent adjustment.
Data Source
AI summary
An exemplary gamma voltage output circuit (3) has an internal resistor string (31), which has a plurality of resistors and a plurality of nodes; at least one external resistor string (32, 33, 34), which has a plurality of resistors and a plurality of nodes; a plurality of switching circuit (35), each switching circuit having at least one input end (353, 354, 355) and at least one output end (356). The internal and the at least one external resistor strings connect in series between the power source AVDD and ground, respectively. Each node outputs a gamma voltage. The nodes of internal and the at least one external resistor strings respectively are connected to the output end and the input end, the resistors of the internal resistor string parallel connecting to corresponding resistors of the at least one external resistor string through the corresponding switching circuit.