LCD Cell Gap Control via Insulating Mediator Layer
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Solution Overview
Problem
In liquid crystal display devices with touch functions, maintaining a uniform cell gap and ensuring uniform alignment of liquid crystal molecules is challenging due to irregularities on the TFT substrate surface, which affects image quality and touch sensitivity.
Innovation Solution
The implementation of a configuration where touch lines and gate lead lines overlap, serving as a pedestal for spacers, and the formation of contact holes that partially overlap touch lines to facilitate uniform alignment film application, helps maintain a consistent cell gap and improves image quality by ensuring proper liquid crystal alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spacers are provided on the counter substrate to control cell gap, then the gap control capability is improved, but the uniformity of cell gap deteriorates due to irregularities on the TFT substrate surface
Solution Approach 1:
An insulating film is introduced as an intermediary layer between the TFT substrate and the spacers on the counter substrate. This insulating film fills in the irregularities and protrusions on the TFT substrate surface, providing a flat base for the spacers to rest on, thereby ensuring uniform cell gap while maintaining the spacer-based gap control capability
2Ease of manufacture
If alignment film liquid is applied to the TFT substrate to control liquid crystal alignment, then the alignment control function is achieved, but the uniformity of alignment deteriorates due to non-uniform application caused by surface irregularities
Solution Approach 1:
The insulating film serves as a mediator between the alignment film liquid and the irregular TFT substrate surface. By providing a flat surface, it enables uniform application of the alignment film liquid, which in turn ensures consistent initial alignment of liquid crystal molecules across the entire display area
3Device complexity
If the TFT substrate surface is kept simple in structure, then the manufacturing complexity is reduced, but the cell gap uniformity deteriorates due to lack of compensating structures
Solution Approach 1:
Instead of modifying the TFT substrate structure to achieve uniformity, the solution moves to another dimension by adding an insulating film layer on the counter substrate side. This approach maintains the simplicity of the TFT substrate while achieving cell gap uniformity through the insulating film that compensates for surface irregularities
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 allows for easier maintenance of a uniform cell gap and prevents image quality degradation by ensuring uniform liquid crystal alignment, enhancing both display and touch functionality.
Implementation Method 1
an alignment film is formed to control initial alignment angles of liquid crystal molecules in the liquid crystal layer
Implementation Method 2
a touch drive signal for detecting a touch position is supplied to the counter electrode, so that a touch detection signal is received via the signal line, and a change in capacitance at the position of the counter electrode is detected
Implementation Method 3
touch sensing is performed by a capacitance method. In this case, a position touched by a user is sensed by detecting, with a touch electrode, a change in capacitance generated when a pointer such as the user's finger or pen touches or approaches a display screen
Data Source
AI summary
A liquid crystal display device includes: transistors and pixel electrodes respectively provided in each pixels; common electrode facing the pixel electrodes; gate lines extending along the first direction and supplying gate signals to the transistors, respectively; gate lead lines extending in the second direction and each connected to a corresponding gate line at at least one of a plurality of intersections with the gate lines; data lines extending along the second direction and supplying data signals to the transistors respectively; and common lines extending along the second direction and connected to the common electrode. In a planar view, each of the common lines and each of the gate lead lines overlap partially.