Embedded Touch Electrodes in LCD Panels for Bezel Reduction
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Solution Overview
Problem
Large-sized liquid crystal display devices face challenges in producing a narrow bezel or borderless structure due to the presence of external buttons, which occupy unnecessary space and hinder the integration of touch sensing functionality within the panel.
Innovation Solution
The integration of touch electrodes formed on the substrate with a conductive layer and routing lines, using a transparent conductive material, allows for touch sensing without external buttons, enabling the formation of a seamless display surface by patterning the transparent conductive film and touch electrodes on the outer surface of the substrate, with a polarizer disposed between the touch electrode and the user's input to sense capacitance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If external buttons are used for touch input, then user input functionality is provided, but bezel size increases and display surface is not seamless
Solution Approach 1:
The patent merges the button function with the display surface by integrating touch electrodes directly into the liquid crystal display panel. The touch electrodes are formed on the same substrate as the liquid crystal cells, combining the display and touch input functions into a single integrated structure, eliminating the need for separate external buttons and enabling a seamless borderless display surface.
Solution Approach 2:
The patent transitions from a mechanical button interface (external, three-dimensional protrusion) to a planar touch electrode interface integrated within the display panel plane. By embedding capacitive touch electrodes in the same plane as the display surface, the solution eliminates the need for external buttons while maintaining input functionality, achieving a borderless design.
2Adaptability or versatility
If touch panel is attached to outside surface of liquid crystal display device, then touch sensing function is added, but additional elements and air gaps are introduced affecting picture quality
Solution Approach 1:
The patent combines the touch panel and liquid crystal display panel into a single integrated structure. The touch electrodes are formed on the same substrate as the liquid crystal cells, eliminating the need for separate attachment of a touch panel overlay. This integration removes additional elements and air gaps that would otherwise interfere with light transmission and degrade picture quality.
Solution Approach 2:
The patent embeds the touch electrode structure within the liquid crystal display panel structure itself. The touch electrodes are nested in the same substrate layer, with the liquid crystal cells and touch electrodes coexisting in an integrated architecture. This nesting approach eliminates the need for separate touch panel layers and adhesives, preserving optical quality.
3Adaptability or versatility
If touch electrodes are formed on substrate with divided electrode pieces, then touch sensing capability is achieved, but device complexity increases
Solution Approach 1:
The patent makes the substrate serve multiple functions: it acts as both the liquid crystal cell substrate and the touch electrode substrate. The same transparent substrate that holds the liquid crystal cells also carries the capacitive touch electrodes, eliminating the need for a separate touch panel substrate. This multi-functionality reduces device complexity while maintaining touch sensing capability.
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 solution allows for the production of large-sized liquid crystal display devices with embedded touch functionality, reducing the bezel size and maintaining picture quality by eliminating additional elements in the cross-section and air gaps, while enabling intuitive user input through touch sensing.
Implementation Method 1
with a polarizer disposed between the touch electrode and the user's input to sense capacitance changes
Data Source
AI summary
A touch display device includes a display panel, a conductive layer disposed on the display panel, a touch electrode disposed adjacent to the conductive layer and on the display panel, a routing line coupled to the touch electrode, and a polarizer disposed on the touch electrode and the conductive layer, where the conductive layer and the touch electrode are formed of the same material.