Fingerprint Sensor Touch Circuit for Sealed Wearable Input
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Solution Overview
Problem
Existing mechanical switches in wearable devices are bulky, prone to electric shocks, and difficult to dustproof and waterproof, while also compromising design aesthetics due to their size and protruding structures, necessitating a more integrated and safer touch input solution.
Innovation Solution
A sensing device incorporating a fingerprint sensor with a touch input pattern, an oscillation circuit, and a detection circuit that generates an oscillation signal based on capacitance changes, allowing for touch detection without the need for external protrusions, and includes a resistor for electrostatic discharge protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical switches are used for touch input, then switching function is achieved, but device size increases and design aesthetics deteriorate
Solution Approach 1:
The patent combines the fingerprint sensor and mechanical switch into a single integrated structure. The touch input pattern is formed using the same conductive layers as the fingerprint recognition pattern, eliminating the need for separate mechanical switch components and reducing overall device volume while maintaining both fingerprint recognition and touch input functions.
Solution Approach 2:
The fingerprint sensor structure serves multiple functions: fingerprint recognition, touch input detection, and button press detection. By making the touch input pattern coincide with or overlap the fingerprint recognition pattern, a single component performs what previously required separate mechanical switches, thereby reducing device size.
2Ease of operation
If mechanical switches are used for touch input, then switching function is achieved, but design aesthetics worsen due to external protrusions
Solution Approach 1:
The patent merges the mechanical switch structure with the fingerprint sensor, eliminating external protrusions. The touch input pattern is integrated into the fingerprint sensor's conductive layers, creating a flush surface that maintains sleek design aesthetics while providing functional touch input capability.
3Ease of operation
If mechanical switches are used for touch input, then switching function is achieved, but dustproof and waterproof capabilities deteriorate
Solution Approach 1:
By integrating the mechanical switch function into the fingerprint sensor structure, the patent eliminates separate moving parts that create openings for dust and water. The unified structure allows for better sealing, improving dustproof and waterproof capabilities while maintaining touch input functionality.
4Ease of operation
If mechanical switches are used for touch input, then switching function is achieved, but electrical safety worsens due to electric shock risk
Solution Approach 1:
The patent replaces the traditional mechanical switch with a capacitive sensing mechanism that detects touch through capacitance changes. This electronic sensing method eliminates direct electrical contact with moving parts, reducing electric shock risk while maintaining touch input functionality through the oscillation circuit and detection circuit.
5Measurement precision
If fingerprint sensor is used alone, then fingerprint recognition is achieved, but touch input function is lost
Solution Approach 1:
The patent makes the fingerprint sensor multi-functional by adding touch input capability. The oscillation circuit is connected to the touch input pattern, and capacitance changes detected by the fingerprint sensor are used to generate oscillation signals that indicate touch occurrences. This allows the same sensor to perform both fingerprint recognition and touch input detection.
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 miniaturization of electronic devices, enhances safety by eliminating electric shock risks, and facilitates dustproof and waterproof designs while maintaining a sleek, integrated appearance.
Implementation Method 1
an oscillation circuit connected to the touch input pattern, and configured to change a capacitance of the oscillation circuit when a touch occurrence is sensed by the touch input pattern, and generate an oscillation signal based on the change in the capacitance
Implementation Method 2
a detection circuit configured to detect the touch occurrence based on a frequency included in the oscillation signal and generate a detection signal
Data Source
AI summary
A sensing device with a fingerprint sensor is provided. The sensing device includes a touch input pattern included in the fingerprint sensor, an oscillation circuit connected to the touch input pattern and configured to change a capacitance of the oscillation circuit when a touch occurrence is sensed by the touch input pattern and generate an oscillation signal based on the change in the capacitance, and an operation detection circuit configured to detect a touch occurrence based on a frequency included in the oscillation signal input from the oscillation circuit and generate a detection signal.