Gamma Voltage Output Circuit Independent Adjustment LCD
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Solution Overview
Problem
Conventional gamma voltage output circuits for LCDs cannot individually adjust gamma voltages without affecting other output levels, limiting precision and flexibility in displaying gray scales.
Innovation Solution
A gamma voltage output circuit with a voltage divider circuit and operational amplifiers, where each operational amplifier's output is grounded via two resistors, allowing independent adjustment of gamma voltages by modifying the resistance of these resistors, enabling precise modulation of each gamma voltage level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a resistor string with multiple resistors connected in series is used to generate gamma voltages, then the gamma voltage levels can be generated, but adjusting the resistance of one resistor affects all other output gamma voltages
Solution Approach 1:
The patent divides the single resistor string into multiple independent resistor pairs (R1a-R1b, R2a-R2b, R3a-R3b, etc.), where each pair is independently connected to a specific operational amplifier. This segmentation allows each gamma voltage to be adjusted independently by modifying only its corresponding resistor pair, without affecting other gamma voltage levels.
Solution Approach 2:
The patent introduces operational amplifiers as intermediary components between the resistor pairs and the output nodes. Each operational amplifier receives a reference voltage and a feedback voltage from its corresponding resistor pair, then outputs the desired gamma voltage. This intermediary structure isolates the adjustment of one resistor pair from affecting other outputs.
2Manufacturing precision
If the resistance of resistors in a resistor string is varied to modulate gamma voltages, then the desired gamma voltage level can be achieved, but the values of other output gamma voltages also vary
Solution Approach 1:
The patent segments the gamma voltage generation into multiple independent circuits, each consisting of an operational amplifier and its corresponding resistor pair. This segmentation ensures that precision adjustments to one gamma voltage level do not propagate to other levels, maintaining stability across all outputs.
Solution Approach 2:
The patent applies local quality by making each resistor pair specifically tailored for its corresponding operational amplifier and gamma voltage level. Each local circuit (op-amp + resistor pair) is optimized independently, allowing precise control of individual gamma voltages without compromising the stability of others.
3Device complexity
If a conventional gamma voltage output circuit with a shared resistor string is used, then the circuit structure is simple, but the gamma voltages output from the circuit affect one another and cannot be adjusted individually
Solution Approach 1:
The patent segments the single shared resistor string into multiple independent resistor pairs, each dedicated to a specific operational amplifier. This segmentation increases the number of components but enables individual adjustment of each gamma voltage, achieving adaptability while maintaining reasonable structural organization.
Solution Approach 2:
The patent creates a dynamic and flexible circuit architecture where each resistor pair can be independently adjusted to modulate its corresponding gamma voltage. This dynamic structure allows the circuit to adapt to different display requirements by individually tuning each gamma voltage level without being constrained by a fixed shared resistor string.
Data Source
AI summary
An exemplary gamma voltage output circuit (2) for a liquid crystal display includes a plurality of operational amplifiers (221) and a plurality of resistors (Rn1˜Rn2). Each of the operational amplifiers includes a high voltage input port, a low voltage input port, a non-inverting input port, an inverting input port, and an output port. The high voltage input port of each operational amplifier connects to a same electrical source, and the low voltage input port of each operational amplifier is grounded. The non-inverting input port of each operational amplifier receives a same direct-current voltage, and the output port of each operational amplifier outputs a gamma voltage configured for driving the liquid crystal display and is grounded via two respective of the resistors connected in series. A node between the two respective resistors connects to the inverting input port of the operational amplifier.