Touch Panel Electrode Non-Formation Portion Noise Isolation
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Solution Overview
Problem
Conventional touch panels face challenges in maintaining precision for detecting pressing forces while minimizing the number of films, which affects thickness and translucency, and are prone to noise interference between capacitive and pressure sensor units.
Innovation Solution
A touch panel configuration with a capacitive touch panel unit and a pressure sensor unit, where the pressure sensor electrodes are formed in the same electrode layer as the touch panel electrodes but with non-formation portions to prevent signal leakage, using uniaxially stretched polylactic acid for enhanced piezoelectricity and translucency, and multiple pressure detection circuits to improve sensitivity and prevent voltage offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the total number of films in the touch panel is increased to separate the capacitive touch panel unit and pressure sensor unit, then noise interference between units is reduced, but the thickness of the touch panel increases and translucency is reduced
Solution Approach 1:
The patent combines the capacitive touch panel unit and pressure sensor unit into a single integrated structure where both units share common electrodes and films. The first and second touch panel electrodes are formed on the same first film, and the first and second pressure sensor electrodes are formed on the same second film, eliminating the need for separate film layers for each unit while maintaining functional separation through electrode configuration.
Solution Approach 2:
The patent introduces a non-formation portion in the second pressure sensor electrode that acts as an intermediary barrier. This non-formation portion prevents direct electrical connection between the capacitive touch panel unit and pressure sensor unit, blocking noise interference while maintaining the integrated thin structure. The non-formation portion serves as a spatial separator that allows both units to coexist in the same film layers without electrical interference.
2Reliability
If the total number of films in the touch panel is increased to separate the capacitive touch panel unit and pressure sensor unit, then noise interference between units is reduced, but the translucency of the touch panel is reduced
Solution Approach 1:
The patent merges multiple functional units into a reduced number of film layers. By forming both touch panel electrodes and pressure sensor electrodes on the same first and second films respectively, the patent reduces the total film count from what would be required for separate units, thereby maintaining higher light transmission and translucency while achieving both touch and pressure detection functions.
Solution Approach 2:
The non-formation portion in the second pressure sensor electrode serves as an intermediary that provides electrical isolation without requiring additional film layers. This allows the touch panel to maintain its translucency by avoiding extra films that would block light, while still preventing noise interference between the capacitive and pressure sensing units through the electrical barrier created by the non-formation portion.
3Length of stationary object
If the capacitive touch panel unit and pressure sensor unit are placed close together to reduce film count, then the touch panel thickness is reduced, but noise leakage from capacitive unit to pressure sensor unit occurs
Solution Approach 1:
The non-formation portion in the second pressure sensor electrode acts as an intermediary barrier that prevents noise leakage between the capacitive touch panel unit and pressure sensor unit. By creating a spatial gap or discontinuity in the electrode configuration at critical positions, this intermediary structure blocks the propagation of electrical noise while allowing the two units to remain in close proximity within the same film layers, thus maintaining thin profile without sacrificing detection precision.
4Illumination intensity
If the capacitive touch panel unit and pressure sensor unit are placed close together to reduce film count, then the translucency of the touch panel is maintained, but noise leakage from capacitive unit to pressure sensor unit occurs
Solution Approach 1:
The non-formation portion serves as an intermediary that provides electrical isolation between the capacitive and pressure sensing units without requiring additional translucent films. This allows the touch panel to maintain high translucency by avoiding extra film layers while still preventing noise interference through the electrical barrier created by the discontinuous electrode configuration in the non-formation region.
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 enhances the precision of pressing force detection, reduces the thickness of the touch panel, and maintains high translucency by minimizing noise interference and film count, while ensuring stable pressure detection sensitivity.
Implementation Method 1
The film 304 is made of a material having piezoelectricity for generating charges on the top surface and the bottom surface with extension and contraction in the in-plane direction
Implementation Method 2
capacitance between the touch panel electrode 312 and the touch panel electrode 311 is changed in the vicinity of the touch position
Data Source
Figure 1
Figure 2(A)~2(C)
Figure 3(A)~3(B)
AI summary
The present invention provides a technology with which precision in detecting pressing can be enhanced, even if the total number of films in a touch panel is decreased. The touch panel (10) includes a capacitive touch panel unit (15) and a pressure sensor unit (16), wherein the capacitive touch panel unit (15) includes a film (11) and touch panel electrodes (31, 32), and the pressure sensor unit (16) includes a film (13) and pressure sensor electrodes (41, 42). An electrode layer in which the pressure sensor electrode (41) is formed is the same as an electrode layer in which the touch panel electrode (32) is formed, and an electrode layer in which the pressure sensor electrode (42) is formed has a non-formation portion where the pressure sensor electrode (42) is not formed, at the position opposite to the touch panel electrode (32).