Double-Layered Auxiliary Lines for LCD Touch Sensing
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Solution Overview
Problem
In liquid crystal display (LCD) devices, the integration of touch functionality leads to short-circuit issues between x and y sensing lines due to their formation at the same layer, necessitating the use of auxiliary lines with increased width or thickness, which compromises the aperture ratio and causes non-uniformity in gate line patterns.
Innovation Solution
The implementation of a double-layered auxiliary line configuration, where a first auxiliary line is connected to a blocking pattern and a second auxiliary line, both formed at the same layer and material as the gate line, prevents short-circuiting by increasing the cross-sectional area for charge flow and reducing resistance per unit area without thickening the gate line, thus maintaining uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the auxiliary line width or thickness is increased to prevent short-circuit between sensing lines, then the resistance per unit area is reduced, but the aperture ratio is compromised and gate line pattern uniformity is degraded
Solution Approach 1:
The patent introduces a vertical dimension by forming the auxiliary line at a different layer (first auxiliary line at first layer, second auxiliary line at second layer) rather than increasing horizontal width at the same layer. This multi-layer configuration prevents short-circuits between x and y sensing lines while maintaining the aperture ratio, as the auxiliary lines occupy different vertical spaces without expanding the horizontal footprint.
2Reliability
If the auxiliary line width or thickness is increased to prevent short-circuit between sensing lines, then the resistance per unit area is reduced, but the gate line pattern uniformity is degraded
Solution Approach 1:
The patent resolves the uniformity issue by transitioning from a single-layer thick auxiliary line to a multi-layer configuration. Each layer maintains standard thickness, ensuring uniform etching and deposition processes. The first auxiliary line at the first layer and second auxiliary line at the second layer both have controlled, uniform thickness, preventing the non-uniformity that would result from increasing the thickness of a single auxiliary line.
3Device complexity
If the sensing lines are formed at the same layer, then the device complexity is reduced, but short-circuit between x and y sensing lines occurs
Solution Approach 1:
The patent segments the auxiliary line function across multiple layers. The first auxiliary line at the first layer and the second auxiliary line at the second layer are separated by an insulating interlayer, creating distinct functional segments that prevent electrical short-circuits while collectively providing the auxiliary sensing function. This segmentation allows both x and y sensing lines to coexist without direct contact.
Solution Approach 2:
The insulating interlayer formed between the first auxiliary line and second auxiliary line acts as an intermediary that prevents electrical contact between the x and y sensing lines. This intermediate insulating layer allows the auxiliary lines to be positioned close together for low resistance while maintaining electrical isolation through the insulating barrier.
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 enhances the resistance characteristics of signal lines for touch sensing while preventing short-circuits and maintaining the LCD's aperture ratio, allowing for effective touch position recognition and operation without the non-uniformity issues associated with increased thickness.
Implementation Method 1
The two substrates include electrodes that face each other such that a voltage applied between the electrodes induces an electric field across the liquid crystal material. Alignment of the liquid crystal molecules in the liquid crystal material changes in accordance with the intensity of the induced electric field into the direction of the induced electric field, thereby changing the light transmissivity of the LCD device.
Data Source
AI summary
A liquid crystal display device includes: a first auxiliary line connected to the blocking pattern and below a gate line; a second auxiliary line in each touch block, and located at the same layer as, the first auxiliary line being made of the same material as the gate line; a first connection pattern contacting the first and second auxiliary lines; a common electrode in each touch block; x and y sensing lines on the common line and overlapping the gate and data lines, respectively; a pixel electrode in each pixel region, connected to a drain electrode through a drain contact hole, and including a plurality of openings; and a second connection pattern contacting the first connection pattern and the x sensing line through first and second contact holes, respectively.