Optical Input Device Light Guide Plate Position Detection
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Solution Overview
Problem
Conventional mice suffer from malfunctions due to oxidation and abrasion, while capacitive touch panels become insensitive due to environmental factors, necessitating an input device that can reliably determine an object's position without these issues.
Innovation Solution
An input device with an optical module comprising a light guide plate, a light source, a scattering layer, and a sensor, which emits light that is reflected by an object on the plate's surface, allowing the device to generate position signals based on the reflected light, thereby enabling optical touch functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional mouse wheel is used, then scrolling and control operations can be performed, but the micro-switch oxidizes and the bearing abrasions occur during use leading to malfunction
Solution Approach 1:
The patent replaces the mechanical wheel structure with an optical touch panel that uses light emission and detection to determine object position and movement. The light source emits light that passes through the light guide plate, and the sensor detects light reflected or transmitted by the object, eliminating mechanical wear and oxidation issues entirely.
Solution Approach 2:
The patent introduces a light guide plate as an intermediary medium between the light source and the sensor. This light guide plate guides and distributes light across the touch panel surface, enabling optical detection without direct mechanical contact, thus avoiding bearing abrasion and micro-switch oxidation.
2Ease of operation
If a conventional capacitive touch panel is used, then touch input function is achieved, but the panel becomes insensitive due to environmental factors such as humidity
Solution Approach 1:
The patent replaces the capacitive sensing mechanism with an optical detection system. Instead of detecting touch through electrical capacitance changes that are sensitive to humidity, the system uses light emission and optical detection to sense object position and touch, making it immune to environmental humidity effects.
Solution Approach 2:
The patent changes the detection parameter from electrical capacitance to optical properties (light transmission, reflection, or scattering). This parameter change fundamentally alters the sensing mechanism to be independent of environmental factors like humidity, while maintaining touch input functionality.
3Reliability
If optical touch detection is implemented, then reliability is improved by avoiding oxidation and abrasion, but the device complexity increases due to the optical module structure
Solution Approach 1:
The light guide plate serves multiple functions simultaneously: it acts as a light distribution medium, a touch sensing surface, and a protective layer. The scattering layer also serves dual purposes by controlling light distribution patterns and enhancing touch detection sensitivity. This multi-functionality reduces the need for separate components, thereby managing device complexity.
Solution Approach 2:
The patent merges the light source, light guide plate, scattering layer, and sensor into an integrated optical module. This consolidation combines multiple functional elements into a single unified structure, reducing the number of separate components and simplifying the overall device architecture while maintaining high reliability.
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 input device effectively determines the relative position of an object with respect to the light guide plate's surface, providing a reliable input function similar to conventional mice and touch panels without their drawbacks, such as malfunctions or sensitivity loss due to environmental factors.
Implementation Method 1
When an object approaches or touches the top surface of the light guide plate, at least a part of the penetrating light is reflected by the object to form a reflected light passing through the light guide plate and being received by the sensor
Implementation Method 2
The scattering layer is configured to change a reflection path of parts of the light on the bottom surface so that the light is projected out of the top surface by the scattering layer to form a penetrating light
Data Source
AI summary
An input device comprising an optical module having a light guide plate, a light source, a scattering layer and a sensor is provided. The light guide plate has a top surface, a bottom surface, and a side. The light source emits a light to the side. The light travels within the light guide plate. The scattering layer changes a path of parts of the light on the bottom surface so that the light is projected out of the top surface to form a penetrating light. When an object approaches or touches the top surface of the light guide plate, at least a part of the penetrating light is reflected by the object to form a reflected light received by the sensor. According to the reflected light, the input device generates a position signal indicating at least one relative position of the object with respect to the top surface.