Voltage Generator DPDT Switch Wiring Mura
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Solution Overview
Problem
In liquid crystal displays, the use of digital-to-analog converters to generate gamma voltages often results in uneven loading on wirings due to resistance mismatching, leading to the 'mura' phenomenon, characterized by dark spots and clouding.
Innovation Solution
A voltage generator comprising a digital-to-analog converting device and a voltage mixer, which converts input voltage to a pair of analog voltages and combines them via electrical wirings, utilizing a DPDT switch and operational amplifiers to stabilize loading and reduce circuit area by minimizing the number of wirings needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple wirings are used to transfer voltages from DAC to amplifier, then voltage transfer capability is improved, but circuit area increases and loading uniformity deteriorates
Solution Approach 1:
The patent segments the voltage transfer function by using a DPDT switch to selectively connect different DAC output pairs (even or odd-numbered) to the amplifier, allowing voltage transfer capability to be maintained through multiple connection options while physically using only two wirings, thus reducing circuit area
2Area of stationary object
If odd-numbered wirings are used for voltage transfer, then circuit area is reduced, but loading uniformity deteriorates causing mura phenomenon
Solution Approach 1:
The patent applies dynamics by making the wiring connection configuration changeable through the DPDT switch, which can dynamically select between even-numbered and odd-numbered DAC output pairs based on digital code requirements, ensuring loading uniformity is maintained while using only two wirings to minimize circuit area
3Reliability
If more wirings are used to ensure uniform loading, then loading uniformity is improved, but circuit area increases
Solution Approach 1:
The patent makes the two wirings universal by enabling them to connect to multiple different DAC output pairs through the DPDT switch, allowing the same two wirings to serve multiple voltage transfer functions for different gamma voltage levels, thereby maintaining loading uniformity without increasing circuit area
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 solution effectively reduces the 'mura' phenomenon by stabilizing wiring loading and minimizing circuit area, resulting in improved display uniformity and reduced dark spots.
Implementation Method 1
The D/A converting device converts an input voltage to a pair of analog voltages
Implementation Method 2
The voltage mixer receives the analog voltages via electrical wirings to combine one or both of the analog voltages into an output voltage
Data Source
AI summary
A voltage generator includes a digital-to-analog (D/A) converting device configured to convert an input voltage to a pair of analog voltages, and a voltage mixer coupled to receive the analog voltages via electrical wirings to combine one or both of the analog voltages into an output voltage.