Display Device Voltage Amplitude Adjustment for Crosstalk
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Solution Overview
Problem
Image display devices using differential transmission systems face issues with wiring crosstalk, leading to reduced effective voltage amplitudes and potential display noise, while increasing power dissipation and electromagnetic interference (EMI), as they struggle to maintain optimal voltage amplitudes across varying gradation patterns and increasing screen resolutions.
Innovation Solution
An image display device with a voltage amplitude adjusting unit that determines the influence of wiring crosstalk and adjusts the data signal voltage amplitude to exceed the input amplitude specification value by a predetermined value, ensuring efficient transmission and minimizing noise and EMI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage amplitude output from the timing controller is set large to ensure sufficient effective voltage amplitudes above the input amplitude specification, then the data driver can operate properly without display noise, but dissipation power increases and EMI properties deteriorate
Solution Approach 1:
The patent implements dynamic voltage amplitude adjustment by detecting the input video signal's gradation pattern and selectively outputting different voltage amplitudes. When the input signal contains patterns prone to wiring crosstalk (e.g., alternating 1010 or 0101 patterns), the timing controller increases the voltage amplitude to exceed the input amplitude specification. For other patterns, it maintains a lower voltage amplitude, thus dynamically adapting the voltage level to signal conditions rather than using a fixed high amplitude, reducing overall power dissipation while ensuring reliability when needed.
Solution Approach 2:
The patent changes the voltage amplitude parameter based on the detected gradation pattern of the input video signal. By analyzing the signal characteristics and adjusting the output voltage amplitude accordingly, the system optimizes the balance between maintaining sufficient effective voltage for reliable data driver operation and minimizing power dissipation and EMI. This parameter adaptation allows the system to use higher voltages only when necessary to overcome wiring crosstalk effects.
2Reliability
If the voltage amplitude is set large to overcome wiring crosstalk effects, then display noise is reduced, but electromagnetic interference properties deteriorate
Solution Approach 1:
The system dynamically adjusts the output voltage amplitude based on real-time detection of the input video signal's gradation pattern. When patterns susceptible to wiring crosstalk are detected, the voltage is increased to maintain signal integrity and reduce display noise. For patterns less affected by crosstalk, the voltage remains lower, thereby minimizing EMI generation. This dynamic approach ensures signal reliability only when necessary, reducing overall EMI impact.
Solution Approach 2:
The timing controller performs preliminary detection of the input video signal's gradation pattern before outputting the data signal. By identifying patterns that will be prone to wiring crosstalk in advance, the system proactively adjusts the voltage amplitude to prevent signal degradation. This preliminary action allows the system to apply higher voltage only when and where needed, rather than continuously, thus preventing EMI generation during periods when crosstalk compensation is not required.
3Reliability
If inter-wiring spacing or ground wiring is provided to avoid signal interference, then wiring crosstalk is reduced, but the substrate area increases preventing miniaturization
Solution Approach 1:
The patent replaces the mechanical/physical solution of increasing inter-wiring spacing or adding ground wirings with an electrical signal processing solution. Instead of physically separating wirings to reduce crosstalk, the system detects the input video signal characteristics and dynamically adjusts the output voltage amplitude to compensate for wiring crosstalk effects. This substitution allows maintaining compact substrate layout while achieving signal transmission quality through intelligent voltage control rather than physical separation.
Solution Approach 2:
Rather than changing the physical layout parameters (wiring spacing, ground wiring configuration), the patent changes the electrical parameter (output voltage amplitude) in response to detected signal patterns. By adjusting the voltage amplitude based on the input gradation pattern, the system compensates for wiring crosstalk without requiring increased substrate area, thus maintaining miniaturization while ensuring signal transmission quality.
4Loss of energy
If the number of video signal lines is reduced by using differential transmission system, then power consumption and space are saved, but wiring crosstalk between neighboring lines increases
Solution Approach 1:
The patent replaces the physical mitigation approach (increasing wiring spacing to reduce crosstalk) with an electrical signal processing approach. By detecting the input video signal's gradation pattern and dynamically adjusting the output voltage amplitude, the system compensates for the increased wiring crosstalk inherent in compact differential transmission layouts. This allows maintaining reduced power consumption and space utilization while offsetting the crosstalk penalty through intelligent voltage control.
Solution Approach 2:
The system changes the output voltage amplitude parameter based on detected signal patterns to compensate for wiring crosstalk effects. When the input signal contains patterns prone to crosstalk (e.g., alternating gradients), the output voltage is increased to maintain signal integrity despite the close wiring spacing. This parameter adaptation allows the differential transmission system to operate effectively with reduced wiring count while mitigating the increased crosstalk through dynamic voltage adjustment.
Data Source
AI summary
The degree of an influence from wiring crosstalk between signal lines of a data signal transmission line (video signal line) is decided on the basis of an input signal generated in display controlling unit (a timing controller) at a predetermined timing (at each frame period, at each clock pulse period, or at each horizontal period) and, based on a result of the decision, the voltage amplitude of a data signal is adjusted so that it may exceed an input amplitude specification value for data line driving circuits (data drivers) by a predetermined value.