Watch Crown Sensing via Flex Plate Strain Detection
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Solution Overview
Problem
Existing wearable electronic devices face challenges in compactly integrating input systems that effectively detect rotational and translational inputs while minimizing space usage, which can lead to reduced performance due to smaller component sizes.
Innovation Solution
The implementation of a crown input system that includes a mounting bracket, a flex plate, and strain sensing elements, allowing the crown to rotate and translate while detecting deformation through a strain sensing element, thereby reducing the space occupied by sensing systems and enhancing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sensing mechanisms (encoders, resolvers) are used to detect rotational and translational inputs, then measurement precision is maintained, but device volume increases
Solution Approach 1:
The patent replaces traditional mechanical sensing mechanisms (encoders, resolvers) with a strain sensing element that detects deformation of a flex plate. This substitution eliminates complex mechanical components while maintaining detection capability through electrical resistance changes in the strain gauge, thereby reducing sensing system volume while preserving measurement precision
Solution Approach 2:
The patent employs a flex plate as a flexible thin film structure that deforms in response to crown translation. The strain sensing element is coupled to this thin flex plate, allowing the system to detect input forces through minimal material thickness, significantly reducing the volume occupied by the sensing system compared to rigid mechanical sensors
2Ease of operation
If crown translation detection sensitivity is increased, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical translation detection mechanisms with an electrical strain sensing system. The strain gauge directly measures flex plate deformation, providing sensitive detection of crown translation without requiring complex mechanical linkages or multiple sensing components, thus improving ease of operation while reducing device complexity
Solution Approach 2:
The patent utilizes changes in electrical resistance of the strain sensing element as the flex plate deforms. By monitoring this electrical parameter change, the system achieves high sensitivity in detecting crown translation with minimal mechanical complexity, as the strain gauge naturally amplifies small deformations into measurable electrical signals
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
This solution enables efficient detection of rotational and translational inputs with a compact design, maintaining high performance and allowing for more space within the device for other components, such as a larger battery, while providing haptic feedback and biometric sensing capabilities.
Implementation Method 1
a strain sensing element coupled to the flex plate and configured to indicate a deformation of the flex plate
Data Source
AI summary
Embodiments are directed to an electronic watch that includes a housing defining a side wall and a display positioned at least partially in the housing. The electronic watch can include an input system that includes a mounting bracket coupled to the side wall, a crown coupled to the mounting bracket and configured to rotate and translate with respect to the housing and a flex plate coupled to the mounting bracket and configured to bend in response to translation of the crown. The input system can include a sensor element coupled to the flex plate and configured to output a signal indicating an amount of the bend of the flex plate.