Light Guide Switch Panel for Uniform Finger Proximity Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional switch units in vending machines and similar devices require a complex configuration with light projecting and receiving units to detect finger proximity or touch, which complicates the detection process.
Innovation Solution
A simplified switch unit configuration using a first light projecting unit, a light guide plate with first prisms, and multiple light receiving units, where the light guide plate reflects light to compensate for distance-related light decreases, allowing for accurate detection of finger approach or touch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light projecting unit and light receiving unit are used to detect finger proximity or touch, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The light guide plate is segmented into multiple regions with different prism densities. Regions closer to the light projecting unit have lower prism density, while regions farther away have higher prism density. This segmentation allows each region to be optimized for its specific distance from the light source, maintaining uniform detection accuracy across the entire panel without requiring complex additional components.
Solution Approach 2:
Different regions of the light guide plate are given different local properties through varying prism densities. The prism density is locally adjusted based on distance from the light projecting unit, creating a non-uniform distribution that compensates for light intensity variations. This local quality adjustment enables accurate detection across different positions without increasing overall device complexity.
2Adaptability or versatility
If the light receiving unit is positioned farther from the light projecting unit to accommodate multiple push buttons, then more push buttons can be arranged, but detection accuracy decreases due to light intensity reduction
Solution Approach 1:
The physical parameter of prism density is changed across different regions of the light guide plate. By increasing prism density in regions farther from the light projecting unit, the system compensates for light intensity reduction. This parameter change allows light receiving units to be positioned farther away while maintaining detection accuracy, enabling more push buttons to be accommodated.
Solution Approach 2:
The prisms in the light guide plate act as intermediaries that redirect and concentrate light from the light projecting unit to specific regions. By strategically placing and density-adjusting these intermediary elements, the system ensures sufficient light reaches light receiving units even at greater distances, enabling versatile button layouts without sacrificing detection accuracy.
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 proposed solution enables efficient and accurate detection of finger proximity or touch with a simplified configuration, ensuring consistent detection accuracy across different distances from the light projecting unit.
Implementation Method 1
a plurality of first prisms that reflect the light incident from the incident surface toward the side approached or touched by the finger
Implementation Method 2
receive the light emitted from the exit surface and reflected by the finger approaching or touching the push button
Implementation Method 3
The detection unit detects the approach or touch of the finger depending on the amount of light received by the light receiving unit
Data Source
AI summary
A display selection button 10 comprises a light projecting unit 21, a light guide plate 13, a plurality of light receiving units 22, and a control unit 30. The light guide plate 13 has an incident surface 13a, a plurality of prisms 13d that reflect incident light toward the side approached by a finger and are provided at positions corresponding to push buttons 10c, and an exit surface 13b that emits the light reflected by the prisms 13d in the direction in which the finger approaches or touches. The light receiving units 22 are provided at positions corresponding to the push buttons 10c and receive light reflected from a finger approaching a push button 10c. The prisms13d reflect light so as to compensate for the amount of light that decreases depending on the distance from the light projecting unit 21.