Force-Sensing Crown Assembly for Multi-Axis Input Detection
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Solution Overview
Problem
Existing input mechanisms for small form factor devices, such as watches, lack the ability to detect non-binary amounts of force applied, limiting their functionality in receiving varied user inputs.
Innovation Solution
An input mechanism, such as a crown, equipped with force sensors that utilize capacitive sensors and compliant materials to measure changes in capacitance based on force applied, allowing for the determination of non-binary force amounts and direction, enabling various types of user inputs through rotation, translation, and transverse movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional crown or input mechanism is used in small form factor devices, then the device maintains a compact size, but the input mechanism lacks the ability to detect non-binary amounts of force applied
Solution Approach 1:
The patent replaces traditional mechanical force sensing mechanisms with a capacitive sensing system. The capacitive sensor detects force applied to the crown by measuring changes in capacitance, eliminating the need for complex mechanical force detection mechanisms while enabling non-binary force amount detection.
Solution Approach 2:
The crown is designed to perform multiple functions: rotation for time adjustment, translation for mode switching, and transverse movement with force detection for additional input modes. The capacitive sensor system enables the same physical structure to detect multiple types of user interactions without requiring separate specialized mechanisms for each function.
2Measurement precision
If additional input mechanisms are added to enable force detection, then the force detection capability is improved, but the device size increases
Solution Approach 1:
The patent merges the force detection functionality into the existing crown structure by integrating capacitive sensors within the collar assembly. The capacitive sensor elements are incorporated into the same space occupied by the crown's mechanical components, allowing force detection without adding external bulk to the device.
Solution Approach 2:
The patent uses thin capacitive sensor elements and flexible printed circuit boards to detect force applied to the crown. These thin-film technologies allow the sensing elements to be integrated within the existing crown structure without significantly increasing the device's volume or requiring additional space.
3Adaptability or versatility
If the crown structure is modified to include force sensors, then the functionality is enhanced, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the force detection functionality into discrete capacitive sensor elements that can be independently manufactured and then assembled into the collar structure. This modular approach to sensor integration allows for standardized manufacturing processes and simplifies assembly compared to integrating force sensors directly into the crown's mechanical components.
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 the electronic device to interpret different force amounts as distinct inputs, enhancing the range of user interactions without the need for additional input mechanisms, thereby improving the functionality of small form factor devices.
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
In numerous examples, the electronic device further includes silicone disposed within the separation.
Data Source
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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.