Capacitive 3D Sensor Light-Guide Unit Luminance
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Solution Overview
Problem
Capacitive three-dimensional sensors face reduced luminance when a light source is positioned at the bottom, as multiple layers, including electrode sheets, obstruct the light from reaching the operation surface, compromising visibility, operability, and decorativeness.
Innovation Solution
A capacitive three-dimensional sensor design featuring a light-guide unit with a side surface and operation surface, including a light-guide sheet and an optional decorative sheet, where the light-guide sheet has a calculated bending stiffness and the decorative sheet is bonded via a pressure-sensitive adhesive, allowing efficient light transmission and distribution to the operation surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light source is arranged at the bottom of the sensor device to illuminate the operation surface, then visibility and operability are improved, but the luminance of light reaching the operation surface is reduced due to multiple interposed layers
Solution Approach 1:
The light-guide unit is extracted and positioned immediately below the operation surface, separating the light guiding function from the electrode layers. This extraction allows light to reach the operation surface with minimal obstruction, as the light-guide unit has high light transmittance and is positioned where it can efficiently transmit light without being blocked by multiple electrode layers.
Solution Approach 2:
The light-guide unit acts as an intermediary component between the light source and the operation surface. It mediates light transmission by having high light transmittance and positioning itself immediately below the operation surface, allowing light to pass through with minimal loss while maintaining the necessary structural layers for sensor functionality.
2Illumination intensity
If the light-guide unit is positioned immediately below the operation surface to enhance luminance, then visibility is improved, but the structural arrangement becomes more complex
Solution Approach 1:
The light-guide unit serves multiple functions: it guides light from the light source to the operation surface with high efficiency, maintains the structural integrity of the sensor device, and positions itself in a location that minimizes interference with the electrode layers. This multi-functionality reduces the need for additional components and simplifies the overall structural arrangement.
Solution Approach 2:
The light-guide unit is positioned in the depth direction (Z-direction) immediately below the operation surface, utilizing the vertical dimension to optimize light transmission. This dimensional positioning allows light to travel a short distance through the light-guide unit before reaching the operation surface, maximizing luminance while maintaining a compact overall structure.
3Adaptability or versatility
If multiple layers including electrode sheets are interposed between the light source and operation surface, then the sensor can sense X, Y, and Z directions, but the luminance of light reaching the operation surface is reduced
Solution Approach 1:
The sensor device is segmented into distinct functional layers: the light-guide unit positioned immediately below the operation surface for optimal light transmission, and the electrode layers (X-Y electrode body and Z electrode body) positioned below the light-guide unit for sensing capabilities. This segmentation allows each layer to perform its function with minimal interference from other layers, maintaining both high luminance and full sensing capability.
Solution Approach 2:
The light-guide unit is designed with high light transmittance specifically in the region immediately below the operation surface, where light transmission is most critical. The electrode layers below have optimized properties for sensing, creating local quality differentiation that allows simultaneous optimization of both light transmission and sensing capabilities in different regions of the device.
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 luminance on the operation surface, improving visibility, operability, and decorativeness while maintaining high sensitivity for Z-direction inputs by appropriately positioning the light-guide unit and electrode bodies.
Implementation Method 1
a light-guide sheet configured to guide the light that has entered the light-guide unit from the side surface and output the light toward the light output portion
Data Source
AI summary
A capacitive three-dimensional sensor includes: a light-guide unit having a side surface and an operation surface, the side surface being formed along the Z direction and including a light entering portion, through which light from a light source enters, the operation surface being configured to input the inputs and including a light output portion, from which the light exits; a sheet-like X-Y electrode body configured to sense the inputs in the plane X and Y directions; a deformable body including a sheet-like elastic body; and a sheet-like Z electrode body configured to sense the input in the Z direction. The light-guide unit includes an optional decorative sheet, and a light-guide sheet to guide the light that has entered the light-guide unit from the side surface and output the light toward the light output portion. A total of bending stiffnesses of the light-guide sheet and decorative sheet is less than 256.