Capacitive Touch Screen Shielding Layer Reduces Side Light Reflection
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Solution Overview
Problem
Capacitive touch screens experience significant side light reflection due to the sloped edges of insulating pads, which interferes with the viewing of the display screen, especially in well-lit environments.
Innovation Solution
A capacitive touch screen design featuring a transparent insulating layer with through holes at each jumper portion, allowing electrical connection between the second connection portion and second electrode blocks, and a shielding layer with minimized shielding blocks to reduce side light reflection. The shielding layer is sandwiched between the substrate and the touch control circuit layer, with shielding blocks corresponding to the through holes to minimize their impact on transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulating pads with sloped edges are used to ensure insulation and manufacturing feasibility, then insulation between connection portions is improved, but side light reflection increases
Solution Approach 1:
The patent extracts the harmful reflective edges from the insulating pad structure by introducing through-holes that remove the sloped edge portions. The insulating pad is configured with through-holes passing through its thickness, effectively eliminating the sloped edges that cause side light reflection while maintaining the insulating function between connection portions.
Solution Approach 2:
The insulating pad is designed with a porous structure containing through-holes. This porous configuration allows the insulating pad to maintain its insulating properties while removing the continuous sloped edge surface that reflects light. The through-holes create a structure where light cannot reflect off continuous surfaces.
2Reliability
If through holes are added to insulating layer for electrical connection, then electrical connectivity is improved, but side light reflection is reduced
Solution Approach 1:
The patent extracts the harmful reflective surfaces by creating through-holes in the insulating layer. These through-holes remove the material that would otherwise create sloped edges reflective to side light, while simultaneously providing pathways for electrical connection between conductive layers.
Solution Approach 2:
The through-holes act as intermediaries that serve dual functions: they provide electrical connection pathways between conductive layers while also serving as light-blocking structures that prevent side light reflection. The edges of the through-holes are designed to block reflected light from reaching the viewer.
3Object-affected harmful factors
If shielding blocks are added to reduce side light reflection, then side light reflection is reduced, but transparency of touch control zone is affected
Solution Approach 1:
The patent applies local quality by making the shielding function localized to specific areas rather than across the entire touch control zone. The shielding blocks are positioned only at the through-hole locations where reflection occurs, leaving the majority of the touch control zone transparent and unaffected.
Solution Approach 2:
The patent uses color/optical property changes by making the shielding blocks non-transparent or dark-colored to block reflected light, while limiting their size and distribution to minimize impact on the overall transparency of the touch control zone. The shielding blocks are strategically placed to block only the reflected light paths.
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
Effectively reduces side light reflection and its interference with the touch screen display, maintaining transparency while providing a jumper connection between electrodes, thus enhancing the usability of the capacitive touch screen in bright environments.
Implementation Method 1
surfaces of the insulating pad 233 generally reflect incident light. Therefore, when the capacitive touch screen is used under a strongly lighted environment, ambient light (a) coming from a sideward direction may be reflected by a sloped edge of the insulating pad 233 towards a front side as reflected light (a′)
Data Source
AI summary
A capacitive touch screen, having a first transparent substrate provided with a touch circuit layer. The touch circuit layer is provided with first and second electrodes and a jumper portion. The touch screen is further provided with an insulating layer. The insulating layer is continuously disposed in an entire transparent touch area of the touch screen, and is provided with through holes at the jumper portion to form a jumper connection of the second electrode. The touch screen further includes a shielding layer sandwiched between the first transparent substrate and the touch circuit layer, and contains multiple shielding blocks. The shielding blocks correspond to the through holes, and the contours of the shielding blocks are formed by expanding the contours of the through holes outwards. The capacitive touch screen can effectively reduce side light reflection on an edge slope of the insulating layer, thereby avoiding interference with display.