Black Electrode Substrate Lamination for Touch Displays
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Solution Overview
Problem
Conventional display devices with integrated touch panels face challenges such as increased thickness and weight, difficulty in achieving high-definition touch sensing, and visibility issues due to light reflection from metal films, especially when using high-definition color filter substrates with organic film bases that are prone to thermal expansion and alignment problems.
Innovation Solution
A black electrode substrate with a laminated structure comprising a transparent substrate, indium-containing layers, copper-containing layers, and carbon-based black layers, which provides high adhesion and low resistance for touch sensing electrodes, improving visibility and alignment of high-definition pixel patterns without the need for a separate touch panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate touch panel is added to the display device, then touch sensing functionality is achieved, but the entire thickness and weight of the display device increase
Solution Approach 1:
The patent combines the touch sensing electrode with the black electrode in the liquid crystal cell, creating an integrated in-cell touch display structure. The black electrode serves dual functions as both the common electrode for liquid crystal control and the touch sensing electrode, eliminating the need for a separate touch panel layer and reducing overall device thickness and weight.
2Manufacturing precision
If high definition pixels with small pitch are used, then display resolution is improved, but alignment between patterns becomes difficult due to thermal expansion of organic film
Solution Approach 1:
The patent changes the material parameter from organic film to glass substrate, which has superior dimensional stability and resistance to thermal expansion. This allows for precise alignment of high-definition pixel patterns (400 ppi or 500 ppi) without the alignment issues that plague organic film-based displays.
3Reliability
If a light-shielding metal film is used in the black electrode, then electrical conductivity is improved, but visibility decreases due to light reflection
Solution Approach 1:
The patent employs a composite material structure for the black electrode, combining a metal film (such as aluminum or copper) with a black resin material. The metal layer provides the necessary electrical conductivity for touch sensing, while the black resin coating suppresses light reflection and improves visibility, creating a multi-functional electrode that addresses both electrical and optical requirements.
4Weight of stationary object
If organic film is used as base material for touch panel, then weight is reduced, but adhesion to metal wiring becomes insufficient
Solution Approach 1:
The patent introduces an intermediary layer (adhesion promoter or barrier layer) between the metal wiring and the resin material. This intermediary layer improves adhesion strength and prevents peeling of the metal wiring, while still maintaining the lightweight advantage of using resin-based materials in the display structure.
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 enables a thin, lightweight display device with improved touch sensing capabilities and visibility by using a black electrode substrate with a laminated structure that enhances adhesion and electrical connectivity, allowing for precise alignment of high-definition pixel patterns and reduced light reflection.
Implementation Method 1
a copper-containing layer disposed on the first indium-containing layer, and containing copper
Implementation Method 2
a first indium-containing layer disposed on the first black layer, and containing indium
Implementation Method 3
a first black layer disposed in the display region and the outer region of the second surface, and containing carbon as a major color material
Implementation Method 4
a black wiring having a laminated structure composed of the first black layer, the first indium-containing layer, the copper-containing layer, the second indium-containing layer and the second black layer
Data Source
Figure 1~2B
Figure 3
Figure 4~5
AI summary
A black electrode substrate (100) of the present invention includes a transparent substrate provided with a first surface (15a) serving as a touch-sensing input surface, a second surface (15b) disposed on an opposite side of the first surface (15a), a display region (15c) defined on the second surface (15b), and having a rectangular shape in plan view, and an outer region (15d) defined on the second surface (15b) and located at an outer side of the display region (15c); a first black layer (1) disposed in the display region (15c) and the outer region (15d) of the second surface (15b), and containing carbon as a major color material; a first indium-containing layer (2) disposed on the first black layer (1), and containing indium; a copper-containing layer (3) disposed on the first indium-containing layer (2), and containing copper; a second indium-containing layer (4) disposed on the copper-containing layer (3), and containing indium; a second black layer (5) disposed on the second indium-containing layer (4), and containing carbon as a major color material; a black electrode pattern (60) defined by a black wiring (6), forming a plurality of pixel opening portions (8) in the display region (15c) and having a terminal portion, the black wiring (6) having a laminated structure composed of the first black layer (1), the first indium-containing layer (2), the copper-containing layer (3), the second indium-containing layer (4) and the second black layer (5), the terminal portion being formed such that the second indium-containing layer (4) in the laminated structure of the black wiring (6) disposed in the outer region (15d) is exposed therefrom; and a transparent resin layer (9) formed on the display region (15c) to overlap the black electrode pattern (60), and having a rectangular shape of which the size is the same as that of the display region (15c) in plan view.