In-Cell Touch Display Layer Inversion for Signal Shielding
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Solution Overview
Problem
In in-cell touch display devices, external touch signals are often shielded by the display electrode on the upper substrate, leading to failure of the touch function when integrated with reflective liquid crystal display elements like ECB-LCD, TN-LCD, and VA-LCD.
Innovation Solution
A touch display device design where the upper substrate with a touch detection structure is placed on the side of the liquid crystal layer facing users, and the common electrode and reflection layer are positioned away from users, allowing external touch signals to be detected without interference from the display electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the common electrode is placed on the upper substrate to achieve display function, then the display performance is improved, but the touch signal is shielded and touch function fails
Solution Approach 1:
The display device is divided into separate functional layers: the upper substrate contains only the touch detection structure, while the common electrode is relocated to the lower substrate. This segmentation allows the touch signal detection and display functions to operate independently without interference, resolving the shielding problem while maintaining both touch and display performance
Solution Approach 2:
Instead of placing the common electrode on the upper substrate as in conventional designs, the patent inverts the layer structure by positioning the common electrode on the lower substrate. This inversion removes the electrode that causes signal shielding from the touch-sensitive side, allowing touch signals to pass through unaffected while the display function is maintained through the reflected light path
2Device complexity
If the touch detection structure is integrated into the array substrate, then the device complexity is reduced, but the touch signal is blocked by display electrodes
Solution Approach 1:
The patent resolves the conflict by changing the spatial dimension of electrode placement. Instead of integrating all electrodes into the upper substrate (2D integration), the solution moves the common electrode to the lower substrate (3D spatial redistribution), maintaining integration benefits while eliminating the harmful shielding effect through proper layer arrangement
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 configuration enables effective realization of the touch function by preventing external touch signals from being shielded, enhancing the touch performance and maintaining the display functionality.
Implementation Method 1
a lower substrate, comprising a common electrode and a reflection layer, the reflection layer being used for reflecting external light
Data Source
AI summary
The present disclosure provides a touch display device, including an upper substrate, a lower substrate, and a liquid crystal layer placed between the upper and lower substrates. The upper substrate includes a touch detection structure, and a plurality of pixel units arranged in a matrix. Each pixel unit includes a switch element and a pixel electrode. The lower substrate includes a common electrode and a reflection layer. The reflection layer is used for reflecting external light, and the external light refers to light from outside and sequentially emitting to the upper substrate and the liquid crystal layer, and then being incident to the reflection layer. In the touch display device, no whole or large area display electrode such as the common electrode is placed between the touch detection structure and the users. Thus, external touch signals will not be shielded, and the touch function can be better realized.