Force-Sensing Crown Structure for Compact Wearable Input
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Solution Overview
Problem
Small form factor devices, such as watches and wearable devices, often have limited input mechanisms that cannot accurately detect non-binary amounts of force applied, limiting the variety of inputs they can receive.
Innovation Solution
An input mechanism, such as a crown, equipped with force sensors like capacitive sensors or strain gauges, that can determine the amount of force applied through changes in capacitance or strain, allowing for various types of user input including rotation, translation, and transverse movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional input mechanisms like crowns are used in small form factor devices, then the device maintains a compact size, but the input mechanism cannot detect non-binary amounts of force applied
Solution Approach 1:
The patent replaces traditional mechanical force detection mechanisms with capacitive sensing technology. The capacitive sensor detects force applied to the crown by measuring changes in capacitance, eliminating the need for complex mechanical switches or buttons while enabling precise detection of varying force magnitudes. This substitution allows the input mechanism to distinguish between different amounts of force (e.g., light press vs. hard press) without increasing mechanical complexity.
Solution Approach 2:
The patent utilizes changes in capacitance as a parameter to detect and measure applied force. By monitoring the capacitance value variations in response to different force magnitudes, the system can differentiate between binary and non-binary force amounts. This parameter-based approach enables precise force measurement while maintaining a simple input mechanism structure suitable for small form factor devices.
2Adaptability or versatility
If multiple input mechanisms are added to provide diverse input options, then the variety of inputs increases, but the device form factor increases
Solution Approach 1:
The patent makes the single crown input mechanism universal by enabling it to perform multiple input functions through force detection. The capacitive sensor allows the crown to detect different force magnitudes, directions, and patterns, transforming it into a multi-functional input device that can replace multiple separate input mechanisms. This universality provides diverse input options (push, rotate, press depth variations) while maintaining the compact device form factor.
Solution Approach 2:
The patent introduces dynamic force detection capabilities to the crown, allowing it to respond to varying force magnitudes and patterns. The capacitive sensor captures dynamic input gestures such as different press depths, holding durations, and force application rates. This dynamic responsiveness enables a single input mechanism to provide diverse input options that would traditionally require multiple separate controls, thereby increasing adaptability without increasing device volume.
3Measurement precision
If force sensors are integrated into the input mechanism, then non-binary force amounts can be detected, but the manufacturing complexity increases
Solution Approach 1:
The patent replaces complex mechanical force sensing mechanisms with capacitive sensors, which are easier to manufacture and integrate. Capacitive sensing technology uses electrical fields rather than mechanical components, eliminating the need for precision-machined force transmission elements, springs, or levers. This substitution simplifies the manufacturing process while maintaining the ability to detect non-binary force amounts with high precision.
Solution Approach 2:
The patent leverages the electrical parameter of capacitance to detect force, which simplifies manufacturing compared to mechanical solutions. By measuring capacitance changes in response to applied force, the system achieves precise force measurement using standard capacitive sensing techniques that are well-established in the industry. This approach avoids complex mechanical assemblies and reduces manufacturing steps, making the input mechanism easier to produce while maintaining high measurement 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 devices to interpret different amounts of force as distinct inputs, enhancing the range of user interactions without increasing the number of input mechanisms, thus improving usability and functionality.
Implementation Method 1
The collar includes a moveable conductor, a conductive element, and a separation defined between the moveable conductor and the conductive element. Movement of the input structure changes a capacitance between the moveable conductor and the conductive element.
Implementation Method 2
silicone disposed within the separation
Data Source
AI summary
An input mechanism, such as a crown, detects amounts of applied force. In various examples, an assembly including an input mechanism has an enclosure; a stem coupled to the enclosure such that the stem is rotatable, translatable, and transversely moveable with respect to the enclosure; a sensor, coupled between the stem and the housing, to which force is transferred when the stem moves with respect to the housing; and a processing unit coupled to the sensor. The processing unit is operable to determine a measurement of the force, based on a signal from the sensor.