Capacitive Touch Panel Light Shielding Layer Segmentation
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Solution Overview
Problem
In capacitive touch panels integrated into display devices, the difference in thermal expansion coefficients between the base and light shielding layers can cause internal stress, leading to potential separation of the light shielding layer from the base, and the connection portions of the detection wiring may be visible due to the light shielding layer's thickness limitations.
Innovation Solution
The implementation of a dual light shielding layer configuration, where the first light shielding layer is positioned on one main face and the second light shielding layer overlaps with it in plan view, ensuring the connection portion of the detection wiring is obscured, while maintaining a relatively thin light shielding layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the thickness of the light shielding layer is increased to prevent visibility of the connection portion, then the visibility of the connection portion is reduced, but internal stress occurs due to thermal expansion difference and the light shielding layer may separate from the base
Solution Approach 1:
The light shielding layer is divided into multiple segments (first light shielding layer and second light shielding layer) that are positioned at different locations. Each segment has a smaller individual thickness, which reduces internal stress from thermal expansion while collectively providing sufficient optical shielding when viewed from the front surface.
Solution Approach 2:
The solution transitions from using a single thick light shielding layer to using multiple thinner layers positioned at different spatial locations (different dimensions). The first light shielding layer is positioned near the connection portion, while the second light shielding layer is positioned elsewhere, creating a multi-dimensional arrangement that achieves both stress reduction and effective shielding.
2Reliability
If the thickness of the light shielding layer is decreased to reduce internal stress, then separation of the light shielding layer is reduced, but the connection portion becomes visible through the light shielding layer
Solution Approach 1:
Instead of using one thin layer that would fail to shield, the light shielding function is segmented into multiple thin layers positioned at different locations. Each layer is thin enough to avoid excessive stress, but the combined arrangement provides sufficient shielding coverage.
Solution Approach 2:
The first light shielding layer acts as an intermediary element positioned specifically to shield the connection portion of the detection wiring. This intermediary layer provides targeted shielding where needed without requiring the entire light shielding structure to be thick, thus maintaining reliability while achieving the shielding function.
3Device complexity
If a single light shielding layer is used, then the structure is simple, but it cannot simultaneously prevent separation and ensure adequate shielding when thin
Solution Approach 1:
The light shielding function is segmented into multiple independent layers rather than using a single monolithic layer. This segmentation allows each layer to be thin and flexible, reducing stress and separation risk, while the collective arrangement provides comprehensive shielding coverage.
Solution Approach 2:
The solution adds dimensional complexity by positioning light shielding layers at different locations in space rather than using a single layer. The first light shielding layer is positioned to shield the connection portion, while the second light shielding layer is positioned elsewhere, creating a multi-layered spatial arrangement that achieves effective shielding without excessive thickness.
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 reduces the visibility of the connection portion of the detection wiring while maintaining a thin light shielding layer, addressing the issue of internal stress and visibility concerns.
Implementation Method 1
a first light shielding layer on the first main face or the second main face of the base and located on the first main face side of the base as compared to the detection wiring; and a second light shielding layer on the first main face or the second main face of the base
Data Source
AI summary
[Object] To provide an input device, a display device, and a mobile terminal which can reduce a possibility that at least a connection portion in detection wiring may be viewed by a user while making the thickness of a light shielding layer relatively small.[Solution] An input device X1 includes a base 2 which includes a first main face 2a and a second main face 2b located on a side opposite to the first main face 2a; a first detection electrode pattern 3 on the second main face 2b of the base 2; detection wiring 8 on the second main face 2b of the base 2 and including a connection portion 8a connected to the first detection electrode pattern 3; a first light shielding layer 6 on the first main face 2a or the second main face 2b of the base 2, and located on the first main face 2a side of the base 2 as compared to the detection wiring 8; and a second light shielding layer 11 on the first main face 2a or the second main face 2b of the base 2, in which the first light shielding layer 6 has a first region which overlaps with the second light shielding layer 11 in plan view, and at least the connection portion 8a in the detection wiring 8 is located by being overlapped with the first region in plan view.