Gamma Voltage Generator for LCD Color Pixel Control
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Solution Overview
Problem
Conventional gamma voltage generators in LCD devices require numerous external reference voltages for optimal adjustment, leading to impractical implementations and inability to individually control color pixel units, resulting in suboptimal color image adjustment.
Innovation Solution
A gamma voltage generator design utilizing multiple potential dividers to generate main and sub-gamma voltages, allowing for independent control of color pixel units by selecting appropriate voltages based on gray level requirements, reducing the need for extensive external reference voltages and enabling individual color adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple external reference voltages are provided for optimal gray level adjustment, then the display accuracy and color calibration are improved, but the device complexity and manufacturing cost increase significantly
Solution Approach 1:
The gamma voltage generator uses internal resistor strings to automatically generate the required reference voltages from a single external voltage source (VDDA). The system self-calibrates by dividing VDDA into multiple reference voltage levels (Vref1, Vref2, Vref3, Vref4) through internal potential division, eliminating the need for external reference voltage inputs while maintaining accurate gray level control.
Solution Approach 2:
A single external voltage input (VDDA) serves multiple functions by being divided into four different reference voltage levels through the resistor strings. This universal voltage source replaces what would traditionally require four separate external voltage inputs, simplifying the device interface while maintaining the capability for precise gray level adjustment across all four color pixel units.
2Adaptability or versatility
If separate control voltages are provided for each color pixel unit, then the color image calibration is improved, but the number of required reference voltages and device complexity increase
Solution Approach 1:
The gamma voltage generator is divided into four independent control channels, each with its own resistor string (first, second, third, and fourth resistor strings). Each channel can independently generate reference voltages for its associated color pixel unit (red, green, blue, and yellow), enabling individual color calibration while using a unified architecture that shares the common VDDA source and control logic.
Solution Approach 2:
Each color pixel unit is assigned dedicated resistor strings and reference voltage generation circuits tailored to its specific calibration requirements. The first resistor string generates voltages for the first color pixel unit, the second for the second color pixel unit, and so on, allowing each color channel to have optimized voltage characteristics while maintaining overall system integration.
3Device complexity
If a single reference voltage source is used for all color pixel units, then the device complexity is reduced, but the ability to individually control each color pixel unit is lost
Solution Approach 1:
The system transitions from a single-dimension voltage control approach to a multi-dimensional voltage generation approach. While all color pixel units share the same external voltage source (VDDA) in the first dimension, each unit receives differentiated reference voltages through separate resistor strings in the second dimension, enabling both simplification and individual control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances LCD image quality by allowing precise control of each color pixel unit, reducing the number of required external reference voltages and maintaining cost-effectiveness, while improving color calibration and display accuracy.
Implementation Method 1
A first potential divider is coupled between a first node and a second node for generating a first main gamma voltage. The second potential divider is coupled between the second node and a third node for generating a first sub-gamma voltage and a second sub-gamma voltage.
Data Source
AI summary
A gamma voltage generator can control brightness of a first color pixel unit and a second color pixel unit. A first potential divider is coupled between a first node and a second node for generating a first main gamma voltage. At least one second potential divider is coupled between the second node and a third node for generating a first sub-gamma voltage and a second sub-gamma voltage. The brightness of the first color pixel unit is controlled by the first main gamma voltage and the first sub-gamma voltage. The brightness of the second color pixel unit is controlled by the first main gamma voltage and the second sub-gamma voltage.