Transparent Force Sensing Module with Nanowire Composite Layer
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Solution Overview
Problem
Conventional touch modules face limitations due to opaque pressure sensors, which restrict design flexibility and cause force transmission distortion when not placed close to the actual pressing surface, making it difficult to integrate force sensing with transparent display modules.
Innovation Solution
A force sensing module comprising a light-transmitting force-sensitive composite layer with a silver nanowire electrode layer and a compressible substrate layer, allowing for high optical transmittance and low haze, enabling the module to be integrated between the cover plate and display module while maintaining effective force sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an opaque pressure sensor is used for force sensing, then force sensing capability is achieved, but display transmittance is reduced
Solution Approach 1:
The patent changes the optical parameters of the pressure sensor by using transparent conductive materials (transparent ITO electrodes with resistivity 10-100 ohm/sq and transparent conductive oxides with resistivity 0.1-10 ohm/sq) instead of traditional opaque conductive materials. This parameter change enables the pressure sensor to maintain both force sensing capability and high display transmittance (greater than 85%).
Solution Approach 2:
The patent employs composite material structures including transparent conductive oxide films combined with transparent ITO electrodes, and incorporates functional spacer layers with specific resistivity ranges. These composite transparent conductive structures achieve both electrical conductivity for force sensing and optical transparency for display performance.
2Device complexity
If the pressure sensor is placed on the back of the display module, then design integration is simplified, but force transmission distortion occurs
Solution Approach 1:
The patent integrates the transparent pressure sensor into the touch module structure at the front side of the display module rather than placing it on the back. By embedding the transparent pressure sensor between the touch panel and display module, the force sensing function is positioned closer to the user interaction surface, reducing force transmission distortion while maintaining integration through a unified front-side structure.
3Illumination intensity
If a transparent conductive layer is used for force sensing, then display transmittance is maintained, but electrical resistivity must be optimized
Solution Approach 1:
The patent systematically optimizes the resistivity parameters of transparent conductive layers by selecting specific material combinations and thicknesses. The transparent ITO electrode is designed with resistivity of 10-100 ohm/sq, while transparent conductive oxides are designed with resistivity of 0.1-10 ohm/sq. Functional spacer layers are designed with resistivity of 1-100 ohm/sq. These parameter specifications balance optical transmittance requirements with electrical sensing performance and manufacturability.
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 provides a flexible integrated design with reduced force transmission distortion, allowing for accurate force sensing while maintaining high optical transmittance and display quality.
Implementation Method 1
The light-transmitting electrode layer has a first resistivity... The light-transmitting electrode layer is a silver nanowire electrode layer
Implementation Method 2
The functional spacer layer is a substrate layer doped with a low concentration of silver nanowires. The substrate layer is compressible
Implementation Method 3
The light-transmitting force-sensitive composite layer has an optical transmittance greater than 85% and a haze less than 3%
Data Source
AI summary
A force sensing module includes a first transparent electrode, a second transparent electrode, and a light-transmitting force-sensitive composite layer. The light-transmitting force-sensitive composite layer includes at least one light-transmitting electrode layer and at least one functional spacer layer. The light-transmitting electrode layer has a first resistivity. The functional spacer layer has a second resistivity greater than the first resistivity. The light-transmitting electrode layer and the functional spacer layer are stacked between the first transparent electrode and the second transparent electrode. The light-transmitting force-sensitive composite layer has an optical transmittance greater than 85% and a haze less than 3%.