Sensor-Integrated Illuminated Key Sheet for Thin, Accurate Slide Input
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Solution Overview
Problem
Existing sensor-integrated illuminated key sheets face challenges in reducing thickness while maintaining illumination brightness and slide input sensitivity, due to separate components and millimeter-sized protrusions that increase distance between the key member and coordinate-inputting unit, leading to decreased sensitivity and frequent malfunctions.
Innovation Solution
A sensor-integrated illuminated key sheet design where the light guide sheet functions as the substrate for the capacitance sensor, reducing thickness and maintaining brightness, with the operation section contacting the light guide sheet to decrease distance and enhance sensitivity, and using materials with the same dielectric constant for key tops and frame sheets to prevent malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If millimeter-sized protrusions are formed on the light guide panel to create air spaces, then the optical waveguide characteristics and illumination brightness are improved, but the entire thickness of the input device increases and the distance between the key member and coordinate-inputting unit increases, reducing sensitivity
Solution Approach 1:
The patent merges the light guide panel and coordinate-inputting unit substrate into a single integrated structure. The coordinate-inputting unit substrate serves dual functions as both the structural base for the capacitance sensor and the light guide panel for illumination, eliminating the need for separate air spaces and protrusions. This integration maintains thin profile while achieving both bright illumination and high slide input sensitivity.
Solution Approach 2:
The coordinate-inputting unit substrate is designed to perform multiple functions simultaneously: it serves as the structural substrate for the capacitance sensor, the light guide panel for LED light transmission, and the mounting base for key members. This multi-functionality eliminates the need for separate components and air spaces, resolving the contradiction between thickness and illumination quality.
2Illumination intensity
If millimeter-sized protrusions are formed on the light guide panel, then the optical waveguide characteristics are improved, but the distance between the key member and coordinate-inputting unit increases, causing sensitivity decrease and frequent malfunctions
Solution Approach 1:
By merging the light guide panel and coordinate-inputting unit substrate into one integrated component, the patent eliminates the air spaces created by protrusions. This ensures close contact between the key member and the coordinate-inputting unit, maintaining high sensitivity and reliability for slide input detection while still providing effective illumination through the integrated light guide structure.
3Adaptability or versatility
If individual parts are separately provided in the input device, then the illumination function and coordinate input function are achieved, but the entire thickness cannot be reduced and the size of electronic equipment increases
Solution Approach 1:
The patent combines multiple functional components into a single integrated coordinate-inputting unit substrate that serves as both the capacitance sensor substrate and the light guide panel. This merging maintains all necessary functions (illumination, coordinate detection, key member mounting) while significantly reducing the overall thickness and size of the input device.
Solution Approach 2:
The integrated coordinate-inputting unit substrate performs multiple functions simultaneously: it provides the structural base for the capacitance sensor, acts as the light guide panel for LED illumination, and serves as the mounting substrate for key members. This multi-functionality eliminates the need for separate components, reducing thickness while maintaining full functionality.
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 enables a thinner, more accurate, and reliable slide input with improved sensitivity and reduced malfunctions, while maintaining bright illumination and a stable appearance.
Implementation Method 1
a light guide sheet 13a which transmits light
Implementation Method 2
a capacitance sensor 13 which serves for a slide input
Data Source
AI summary
There is provided a technique which can reduce the entire thickness of a push-button switch while securing the brightness of the illumination and can increase the sensitivity and accuracy of a slide input. Use of a light guide sheet separating from a surface-type capacitance sensor is excluded, thereby being able to reduce the entire thickness of a sensor-integrated illuminated key sheet while a light guide sheet serves to secure the brightness of the illumination. A surface sheet is provided so as to contact the operation surface side of the light guide sheet as the substrate of the surface-type capacitance sensor. The distance between the operation surface of the surface sheet and the surface-type capacitance sensor can therefore decrease, which can enhance the sensitivity and accuracy of the slide input.