Built-In Touch Sensor Layout for Transparent LED Displays
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Solution Overview
Problem
Embedding a touch sensor in a light emitting diode display device is challenging due to various difficulties, preventing the implementation of a transparent display with minimal transmittance degradation and bezel reduction, while also ensuring easy manufacturing and reducing the influence between display and touch driving.
Innovation Solution
A light emitting diode display device with a built-in touch sensor is designed, featuring a substrate with a driving transistor, light emitting diode, and touch sensor electrodes, utilizing reflective and transparent electrode materials, and a touch connection structure that minimizes transmittance degradation and display-to-touch crosstalk, with touch routing lines integrated on the same layer as light shielding patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a touch sensor is embedded in a display panel, then the thickness is reduced and manufacturing is facilitated, but various difficulties prevent implementation
Solution Approach 1:
The touch routing line is positioned in the vertical dimension between the substrate and the touch sensor electrode, rather than trying to embed it in the same plane. This vertical arrangement resolves the integration difficulties by utilizing the z-direction space, allowing all components to coexist without planar interference while maintaining a compact overall structure.
2Illumination intensity
If transparent electrode material is used for the touch sensor electrode, then transparent display is enabled, but transmittance degradation occurs
Solution Approach 1:
The touch routing line uses reflective metal material specifically in regions where it overlaps with the light emitting diode, while the touch sensor electrode maintains transparent material. This localized use of reflective material improves light utilization in the display area without compromising the overall transparency needed for transparent display functionality.
Solution Approach 2:
The structure combines transparent electrode material for the touch sensor electrode with reflective metal material for the touch routing line, creating a composite structure that optimizes both transparency and light reflection properties. The transparent electrode enables light transmission for transparent display, while the reflective routing line minimizes light loss in specific regions.
3Length of stationary object
If the touch routing line is disposed between the substrate and the touch sensor electrode, then bezel reduction is enabled, but manufacturing complexity increases
Solution Approach 1:
The touch sensor structure is segmented into distinct functional layers: the substrate, the touch routing line layer, and the touch sensor electrode layer. This segmentation allows each component to be optimized independently and simplifies the manufacturing process by enabling sequential fabrication of each layer with standard semiconductor processing techniques.
Solution Approach 2:
The touch routing line is arranged in the vertical dimension between the substrate and the touch sensor electrode, utilizing the z-direction rather than extending horizontally in the bezel area. This vertical arrangement reduces the bezel size by eliminating the need for horizontal routing space while maintaining electrical connectivity through the vertical stack structure.
4Power
If reflective metal material is used for the driving voltage line, then light emission efficiency is improved, but touch sensor performance may be affected
Solution Approach 1:
The touch routing line is positioned in the vertical dimension between the substrate and the touch sensor electrode, spatially separating it from the reflective driving voltage line. This vertical separation allows the reflective metal material to be used for light emission efficiency without the routing line interfering with touch sensor performance, as they occupy different vertical positions in the 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 transparent display with reduced bezel and weight, easy manufacturing, and minimized influence between display and touch driving, facilitating integration in vehicles.
Implementation Method 1
light emitting diode included in the subpixel, and including a first electrode and a second electrode
Implementation Method 2
driving voltage line including a reflective metal material
Data Source
AI summary
A light emitting diode display device with a built-in touch sensor according to embodiments of the present disclosure may include a substrate, a driving transistor included in a subpixel, and including an active layer, a source electrode, a gate electrode and a drain electrode, a light emitting diode included in the subpixel, and including a first electrode and a second electrode, a driving voltage line including a reflective metal material, a first electrode connection pattern electrically connecting the driving voltage line and the first electrode, and including a transparent electrode material, a touch sensor electrode including the transparent electrode material, and a touch routing line electrically connected to the touch sensor electrode and disposed between the substrate and the touch sensor electrode.