Optical Keyswitch Assembly for Precise Multi-Stage Actuation
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Solution Overview
Problem
Conventional mechanical keys are too large and complex for use in thin electronic devices, while optical sensing switch keys face challenges in providing precise control without requiring extreme finger pressing techniques, leading to high false actuation rates due to small actuation intervals.
Innovation Solution
A multi-stage optical sensing keyswitch assembly with a keycap, lifting mechanism, and substrate, featuring a shield that interferes with a signal channel to generate different keyswitch signals based on pressing depth, allowing for fine control without increasing the total travel distance or keyswitch height, and incorporating a suitable support frame and elastic member for tactile feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical keys are used, then reliable signal generation is achieved, but the keyboard becomes too large and complex for thin electronic devices
Solution Approach 1:
The patent replaces the mechanical contact-based signal generation system with an optical sensing system. The light emitter and light receiver detect key presses through light interruption, eliminating the need for mechanical contacts and complex mechanical structures, thereby reducing device complexity while maintaining reliability
Solution Approach 2:
The patent introduces a shield as an intermediary element between the light emitter and light receiver. The shield modulates the light path to generate multi-stage signals, enabling reliable signal differentiation without requiring direct mechanical contact or complex sensing mechanisms
2Length of moving object
If optical sensing switch keys with small actuation intervals are used, then thin keyboard structure is achieved, but false actuation rate increases due to small control margins
Solution Approach 1:
The patent segments the light shielding process into multiple stages by using a shield that can be positioned at different depths. This creates distinct actuation stages (first-stage and second-stage signals) within the limited travel distance, improving actuation accuracy by providing clear signal differentiation without increasing overall keyswitch height
Solution Approach 2:
The patent utilizes the vertical dimension of light propagation by positioning the shield to interrupt light at different depths. This multi-stage light shielding approach enables precise control differentiation within the constrained vertical space, maintaining thin structure while improving reliability
3Measurement precision
If multi-stage control is implemented without increasing travel distance, then precise control is achieved, but the shield must be precisely positioned to maximize light shielding effectiveness
Solution Approach 1:
The patent employs a dynamic linking mechanism with a fulcrum that automatically adjusts the shield's position and shielding ratio based on the keycap's pressing depth. This dynamic adjustment eliminates the need for precise static positioning, allowing multi-stage control to be achieved through the mechanical dynamics of the linkage system rather than manufacturing precision
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 smooth operation for non-professional users with reduced false actuation rates by increasing the effective light-shielding distance and allowing for precise control without increasing the keyswitch's size or travel distance, maintaining the thin structure requirement.
Implementation Method 1
pressing the keycap drives the shield to move between the light emitter and the light receiver to interfere with the light emitted from the light emitter to the light receiver
Data Source
AI summary
A keyswitch assembly includes a keycap, a lifting mechanism, a shield, and a substrate. The lifting mechanism includes a keycap end coupled to the keycap and is capable of being driven by a force to move downward by a distance. The shield extends from the keycap end or the keycap and is movable along with the keycap end or the keycap. The substrate is disposed below the lifting mechanism and includes a sensing switch and a keyswitch circuit electrically connected to each other. The sensing switch has a signal channel and is configured to sense a change in sensed intensity caused by interference of the shield with the signal channel to cause the keyswitch circuit to generate at least one keyswitch signal. During movement of the shield with the keycap end or the keycap, the shield interferes with the signal channel as much as possible throughout the entire distance.