Shift Register Input Line Layout for Uniform Display Gate Signals
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Solution Overview
Problem
The increase in wiring line resistance in gate driving circuits of active matrix display devices, particularly in large and high-resolution liquid crystal displays, leads to display quality deterioration due to variations in voltage levels and waveforms, causing brightness unevenness and temperature non-uniformity.
Innovation Solution
The display device incorporates a shift register circuit with input signal lines formed on the same substrate as the scanning signal lines, where at least one input signal line is divided into unit portions, with at least one portion having a lower resistance value than adjacent downstream portions, and the upstream portions have even lower resistance, achieved by varying line widths or lengths to maintain consistent pulse waveforms and temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the display device is made larger and/or has higher resolution, then the display quality is improved, but the wiring line resistance in the gate driving circuit increases causing brightness unevenness
Solution Approach 1:
The patent applies local quality by varying the line width of input signal lines at different positions. Specifically, input signal lines have different line widths corresponding to different resistance values, with wider lines (lower resistance) positioned at locations where higher current flows or where resistance compensation is needed. This local variation in line width compensates for the increased wiring resistance in large/high-resolution displays, maintaining uniform gate signal voltage levels across all pixel rows despite the overall increase in display size and resolution.
2Device complexity
If the gate driving circuit is integrated on the active matrix substrate, then the device complexity is reduced, but the wiring line resistance increases causing waveform variation
Solution Approach 1:
The patent applies parameter changes by modifying the resistance values of input signal lines through varying line widths. The gate driving circuit includes input signal lines with different resistance values tailored to their specific positions and current requirements. This parameter variation compensates for the waveform degradation that would otherwise occur due to the integrated layout, ensuring that gate signals maintain their intended waveforms despite the compact integration on the active matrix substrate.
3Reliability
If the line width of input signal lines is increased to reduce resistance, then the wiring line resistance decreases improving uniformity, but the area occupied by wiring increases
Solution Approach 1:
The patent applies local quality by selectively increasing line width only where needed. Not all input signal lines have the same width; instead, line widths are locally optimized based on position, current requirements, and resistance compensation needs. This approach achieves the necessary resistance uniformity for display quality while minimizing the total wiring area, as wider lines are only used at specific locations rather than uniformly across all wiring.
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 configuration suppresses display quality deterioration by minimizing resistance-induced waveform variations and temperature non-uniformity, ensuring uniform brightness and improved display quality, especially in large and high-resolution displays.
Implementation Method 1
at least one input signal line of the plurality of input signal lines includes a plurality of unit portions when a portion between adjacent branch lines, each of which being the branch line connecting the input terminal to the one of the plurality of input signal lines, is defined as a unit portion, and the plurality of unit portions include at least one first unit portion having a resistance value smaller than a resistance value of the unit portion adjacent thereto on a downstream side in an input direction of the input signal
Data Source
AI summary
A display device includes pixels arranged in a matrix, scanning signal lines, display signal lines, a scanning signal line driving circuit, a display signal line driving circuit, and input signal lines for supplying an input signal to the scanning signal line driving circuit. The scanning signal line driving circuit includes a shift register circuit, and each stage of the shift register circuit includes an input terminal connected to the input signal line via a branch line and an output terminal connected to the scanning signal line. The input signal line includes unit portions when a portion between the adjacent branch lines is defined as a unit portion, and the unit portions include at least one first unit portion each having a resistance value smaller than a resistance value of the unit portion adjacent thereto on a downstream side in an input direction of the input signal.