Touch Sensing Structure With Layered Illumination and Force Threshold
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Solution Overview
Problem
Piezoresistive touch sensing structures suffer from the non-transparent nature of the piezoresistive material layer, which obscures the light-emitting element and affects the visibility of icons on buttons, leading to issues with accidental touches and mistouches due to the shielding effect.
Innovation Solution
A touch sensing structure design featuring a light-shielding layer and a pressure-sensitive element positioned to avoid overlap with the light-emitting element, allowing for improved illumination and accurate touch detection by using reflective layers to enhance brightness and prevent shielding, while ensuring the pressure-sensitive element is only activated by a specific pressing force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a piezoresistive material layer is used in the touch sensing structure, then touch detection function is achieved, but the light-emitting element is obscured and icon visibility is reduced
Solution Approach 1:
The touch sensing structure is divided into separate functional layers: a piezoresistive material layer for touch detection and a light-emitting element for illumination. By segmenting these functions into distinct layers positioned at different depths, the patent resolves the contradiction between touch detection reliability and icon visibility, as the piezoresistive layer no longer obscures the light-emitting element when viewed from the front surface.
2Reliability
If the piezoresistive material layer is placed over the light-emitting element, then touch sensing is enabled, but accidental touches and mistouches occur due to shielding effect
Solution Approach 1:
The patent transitions from a planar arrangement to a three-dimensional layered structure, positioning the piezoresistive material layer and light-emitting element at different depths along the thickness direction. This dimensional separation eliminates the shielding effect that caused accidental touches, while maintaining accurate touch detection capability through the piezoresistive layer's pressure sensitivity.
3Reliability
If the light-emitting element is positioned under the piezoresistive material layer, then touch detection is achieved, but illumination intensity is reduced due to non-transparent material
Solution Approach 1:
The patent introduces a light guide layer as an intermediary between the light-emitting element and the front surface. This light guide layer efficiently distributes and transmits light from the light-emitting element to illuminate the icon, resolving the contradiction between touch detection accuracy and illumination efficiency by providing a dedicated light transmission pathway that is not obstructed by the piezoresistive material layer.
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 design enhances user experience by preventing accidental touches and improving illumination, ensuring that functions are executed only when the correct pressing force is applied, thereby resolving mistouch issues and maintaining clear icon visibility.
Implementation Method 1
a light guide layer, guiding light from the light-emitting element
Implementation Method 2
using reflective layers to enhance brightness and prevent shielding
Implementation Method 3
the button includes a transparent substrate, a piezoresistive material layer
Data Source
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AI summary
A touch sensing structure (10, 20, 30, 40, 50, 60) with improved illumination includes a first substrate (11), a decoration layer (121), a light-shielding layer (122), a light-emitting element (152), a pressure-sensitive element (18), a first reflective layer (131), and a second reflective layer (132). The pressure-sensitive element (18) is farther away than the light-emitting element (152) from the first substrate (11). The decoration layer (121) shows a function icon. The light-emitting element (152) emits light to illuminate the function icon. When the first substrate (11) is pressed, the touch sensing structure (10, 20, 30, 40, 50, 60) determines a magnitude of the pressing force by detecting a change in the resistance or voltage value of the pressure-sensitive element (18). If the pressing force reaches a specific value, the function identified by the function icon is executed, otherwise no function is executed.