Touch Screen Bridge Electrode Visibility Reduction
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Solution Overview
Problem
Existing touch screen panels with bridge electrodes suffer from visibility issues due to reflectance differences, which degrade the image quality of capacitive-type touch screens, especially when the bridge electrode is clearly observable on the display device.
Innovation Solution
A touch screen panel design where the insulation layer and bridge electrode satisfy specific reflectance parameters (Equations 1 and 2) to minimize visibility, with a bridge electrode thickness of 1,400 to 1,800 Å and materials like indium-tin oxide (ITO), indium-zinc oxide (IZO), and an index matching layer (IML) to reduce reflectance and enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bridge electrode is formed on the insulation layer to electrically connect transparent electrode patterns, then electrical connectivity is improved, but visibility of the bridge electrode increases due to reflectance difference
Solution Approach 1:
The patent applies parameter changes by controlling the thickness of the bridge electrode to 50-200 nm and adjusting the refractive index of the insulation layer to 1.8-2.2. By optimizing these parameters, the reflectance difference between the bridge electrode and surrounding areas is minimized, making the bridge electrode visually indistinguishable while maintaining its electrical connectivity function.
Solution Approach 2:
The patent applies local quality by creating a specific refractive index range (1.8-2.2) for the insulation layer that matches the optical properties of the bridge electrode. This localized optimization of the insulation layer's refractive index ensures that the bridge electrode becomes visually imperceptible only in the specific region where it is needed for electrical connection.
2Reliability
If transparent electrode patterns are formed on the entire surface of the display area, then sensing coverage is improved, but visibility degradation occurs due to pattern observation
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness of transparent electrode patterns to 10-100 nm and adjusting their refractive index to match the insulation layer (1.8-2.2). This parameter optimization makes the transparent electrode patterns visually indistinguishable from the surrounding areas while maintaining full-surface sensing coverage.
Solution Approach 2:
The patent applies homogeneity by ensuring that the refractive index of the transparent electrode patterns matches that of the insulation layer (both in the range of 1.8-2.2). This creates optical homogeneity across the entire display area, making the electrode patterns invisible while preserving their electrical and sensing functions.
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
The solution significantly decreases the visibility of the bridge electrode, thereby improving the image quality and maintaining color matching with the display black state, ensuring high image quality in image display devices.
Implementation Method 1
an index matching layer (IML) formed between the base substrate and the sensing pattern layer
Implementation Method 2
a bridge electrode formed on the insulation layer to electrically connect unit patterns isolated from each other of the sensing pattern layer
Data Source
AI summary
A touch screen panel includes a base substrate, a sensing pattern layer on the base substrate, the sensing pattern layer including a plurality of sensing patterns formed on the base substrate, an insulation layer on the sensing pattern layer, and a bridge electrode formed on the insulation layer to electrically connect unit patterns isolated from each other of the sensing pattern layer. The insulation layer and the bridge electrode satisfy parameters according to specific equations so that a visibility of the bridge electrode on the insulation layer is decreased and an image visibility is improved.