Laser Self-Mixing Input Detection for Button-Free Writing
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Solution Overview
Problem
Conventional mice require a left button to be held down for writing or drawing, limiting the movement path detection to a specific lift-off distance, which affects the handwriting and drawing experience.
Innovation Solution
An input detection apparatus integrating lasers and a processor to measure displacements and tilts using laser self-mixing interference, allowing for natural writing or drawing experiences without needing to hold down a button, by determining displacements and tilts based on self-mixing interference signals and relative position information between lasers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional mouse is used for writing or drawing, then the left button area must be held down to detect movement path, but this limits the movement path detection to a specific lift-off distance and affects handwriting and drawing experience
Solution Approach 1:
The patent replaces the mechanical button-pressing system with an optical sensing system using laser self-mixing interference. The laser module detects movement path through optical interference patterns generated when laser light reflects off the surface, eliminating the need for mechanical button activation and enabling natural handwriting/drawing gestures without contact.
Solution Approach 2:
The input detection apparatus integrates multiple functions into a single device: it can detect both mouse-like movement paths and stylus-like handwriting/drawing gestures. The laser self-mixing interference technology enables the device to function as both a conventional mouse and a stylus, adapting to different user needs without requiring separate devices.
2Length of moving object
If the mouse is raised from the desktop by a particular height (lift-off distance), then no matter how the mouse is moved, the movement path cannot be detected
Solution Approach 1:
The patent replaces the mechanical contact-based detection system with an optical field-based system. The laser self-mixing interference technology creates an optical detection field that extends beyond the physical contact surface, allowing detection of movement paths even when the device is raised from the surface, thereby increasing the effective lift-off distance while maintaining detection reliability.
3Ease of operation
If laser self-mixing interference is used to measure displacement and tilt, then natural writing or drawing experience is achieved without button pressing, but the device structure becomes more complex
Solution Approach 1:
The patent merges the laser module, processor, and other functional components into an integrated input detection apparatus. By combining multiple functions (movement detection, tilt detection, button detection) into a single unified device with shared components, the patent reduces overall system complexity while enabling natural writing experiences through laser self-mixing interference.
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
Enables natural writing or drawing experiences similar to using a pen by measuring displacements and tilts, allowing for pen-up and pen-down detection without button pressing, and enhancing writing experience.
Implementation Method 1
The laser may emit laser light, and generate a self-mixing interference signal when the laser light is reflected into a resonant cavity of the laser through a reference plane
Data Source
AI summary
An input detection apparatus: includes at least two first lasers, at least two second lasers, and a processor. Each laser may emit laser light and generate a self-mixing interference signal when the laser light is reflected into a resonant cavity of the laser through a reference plane. The processor may determine a first displacement of the input detection apparatus in the reference plane based on self-mixing interference signals generated by all the first lasers and relative position information between the at least two first lasers, and determine a second displacement of the input detection apparatus in the reference plane based on self-mixing interference signals generated by all the second lasers and relative position information between the at least two second lasers. The processor determines a movement path of the input detection apparatus in the reference plane based on the first displacement and the second displacement.