Finger Navigation Sensor Using Speckle Beam Tracking
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Solution Overview
Problem
Finger navigation technologies in electronic devices, such as capacitive touch pads, face limitations in providing high-resolution position tracking due to the need for sizable components and latency issues, resulting in coarse navigation and increased device footprint.
Innovation Solution
A finger navigation sensor system utilizing a light source and photo detector module to track finger movement by processing speckle beams emitted from a tactile surface, with a capacitive sensing device determining liftoff threshold, allowing for precise and fast tracking with reduced latency and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive touch pad technology is used for finger navigation, then the device can provide touch sensing capability, but the position tracking resolution remains coarse and the device footprint increases
Solution Approach 1:
The patent replaces the mechanical/optical cap-sensing system with an electromagnetic induction-based sensor system. The sensor uses a magnetic field generated by a permanent magnet or magnetized target to detect finger position, eliminating the need for large capacitive sensor arrays and associated wiring, thereby achieving high-resolution tracking in a compact form factor
Solution Approach 2:
The patent changes the sensing parameter from electrical capacitance to magnetic field interaction. By using magnetic field strength and distribution patterns as the sensing parameter, the system achieves higher position resolution without requiring proportionally larger sensor areas, as magnetic field lines can be detected with high precision over small distances
2Speed
If cap-sensing technology is used for finger navigation, then the system can track finger movement, but the response time increases due to latency effects
Solution Approach 1:
The patent replaces the relatively slow capacitive sensing mechanism with electromagnetic induction-based detection. The magnetic field changes detected by the sensor respond instantaneously to finger movement, eliminating the latency inherent in capacitive charge/discharge cycles and mechanical component response times
Solution Approach 2:
The patent employs continuous magnetic field generation and periodic sampling of field strength variations. This periodic measurement approach allows for high-frequency position updates with minimal latency, as the magnetic field is continuously present and ready for immediate detection without requiring charge buildup or mechanical actuation delays
3Reliability
If sizable electronic components are implemented within the electronic device for cap-sensing, then the touch sensing function can be achieved, but the device complexity and component count increase
Solution Approach 1:
The patent extracts and eliminates numerous sizable electronic components (conductive structures, wires, capacitive sensors) by replacing them with a simplified magnetic sensing system. The core functionality is achieved through a permanent magnet and magnetic field sensor, removing the complex capacitive sensing infrastructure while maintaining reliable touch detection
Solution Approach 2:
The patent creates a multi-functional system where the magnetic sensor serves multiple purposes: detecting finger presence, determining position, and sensing touch pressure. This universal approach replaces multiple specialized capacitive sensing components with a single integrated magnetic sensing solution, reducing overall device complexity
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 high-resolution finger navigation in a smaller package with faster response times and reduced latency, suitable for mobile devices, providing precise touch sensing and navigation with reduced power usage.
Implementation Method 1
a light source for illuminating light towards a tactile surface. The sensor system also comprises a photo detector module for sensing speckle beams emitted by a target surface navigating the tactile surface in response to the light hitting the target surface
Implementation Method 2
the lift-off can be determined by a capacitive sensing device positioned within the tactile surface
Data Source
AI summary
Finger navigation methods, devices and systems are disclosed. In one embodiment the system comprises a light source configured to radiate a light beam towards a tactile surface. The system also comprises a photo detector module configured to sense speckle beams emitted by a target surface navigating the tactile surface in response to light hitting the target surface. The system further comprises a processor configured to track a movement of the target surface with respect to the tactile surface based on output from the photo detector module and a conductor structure for capacitive sensing of the target surface with respect to the tactile surface. The conductor structure is configured to determine a plurality of navigational functionalities based on the capacitive sensing of the target surface with respect to the tactile surface, including at least one of single click, double click, and scrolling.