Movable Touchpad Optical Speckle Sensitivity
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Solution Overview
Problem
Traditional touchpads are sensitive to changes in atmospheric pressure, leading to inconsistent operation sensitivity and precision, making them inconvenient for users, especially when moving the cursor over long distances, and often require frequent finger movement, causing fatigue and potential injury.
Innovation Solution
A movable touchpad with a slidable template and an optical detecting device that uses invariant optical speckle imaging to calculate relative displacement, providing high sensitivity and linearity, and includes edge detecting devices for dynamic cursor control, eliminating the need for frequent finger movement and reducing fatigue and injury risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional capacitive or resistive touchpad is used, then the device structure is simple, but the operation sensitivity is affected by atmospheric pressure changes
Solution Approach 1:
The patent replaces traditional mechanical pressure-based detection (resistive) or electrical field detection (capacitive) with an optical detection system. A light source illuminates the template, and an image sensor captures optical images to detect template position and displacement, eliminating sensitivity to atmospheric pressure changes.
Solution Approach 2:
The patent introduces a template as an intermediary element between the user's finger and the detection system. The template physically moves with finger input while its position is optically tracked, separating the mechanical input from the detection mechanism and isolating it from atmospheric pressure effects.
2Ease of operation
If the touchpad sensitivity is increased to improve cursor control, then precise positioning becomes difficult to achieve
Solution Approach 1:
The patent implements dynamic cursor control where the cursor movement speed and distance are determined by the template's displacement magnitude detected through optical imaging. The system processes a series of optical images to calculate displacement, enabling both sensitive response to small movements and precise positioning through computational analysis.
Solution Approach 2:
The system continuously captures optical images of the template, calculates its position and displacement relative to previous frames, and uses this feedback to control cursor movement. This closed-loop approach allows precise positioning while maintaining operational sensitivity.
3Measurement precision
If a slidable template with optical detection is used, then sensitivity and positioning precision are improved, but the device complexity increases
Solution Approach 1:
The template serves multiple functions: it is the element the user touches and slides for input, the physical object whose movement encodes cursor control information, and the reflective surface for optical detection. This multi-functionality reduces the need for separate components and simplifies the overall device structure despite the advanced detection capability.
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 offers improved sensitivity and precision, reducing finger fatigue and injury by allowing smooth cursor movement without the adverse effects of atmospheric pressure changes, providing a more comfortable user experience akin to using a mouse.
Implementation Method 1
an optical detecting device for detecting displacement optical speckle images of the back surface of the slidable template
Implementation Method 2
an image sensor for receiving speckle images formed by light beams scattered by the back surface
Data Source
AI summary
A highly sensitive movable touchpad is disclosed in the present invention. It is used for laptop computers and has a slidable template for users to move so that a cursor can be controlled by the touchpad. A resistive or capacitive detecting surface can be applied for detecting users' click, double click, drag, or scroll motion on any point of the surface. Additionally, there is an optical displacement sensor provided under the slidable template for detecting surface information on the back surface of the slidable template. A sequence of images of surface movement are processed by an image processing unit. Then, relative movement information is calculated and sent to an operating system in the computer. The operating system controls the cursor with the relative movement information. The present invention uses edge detectors for dynamically controlling the cursor and calibrating location of the cursor so that positioning of the touchpad is synchronous with the cursor.