Fingerprint Sensor Touch Detection Mode Switching

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Solution Overview

Problem

Current electronic devices face challenges in accurately detecting touches on fingerprint sensors, particularly when they are located in close proximity to touchpads, as existing technologies struggle to differentiate between fingerprint authentication and touch input for auxiliary device control.

Innovation Solution

The integration of a fingerprint sensor with a higher resolution touch sensor array and a controller that operates in both fingerprint sensing and touch sensing modes, allowing the fingerprint sensor to function as part of a combined touchpad when not in authentication mode, enabling efficient detection and differentiation of touch inputs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the fingerprint sensor is located in close proximity to the touchpad to save device space, then device compactness is improved, but the ability to differentiate between fingerprint authentication and touch input deteriorates

Engineering Contradiction:
Improvedevice compactnessVSAvoidtouch detection accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The system dynamically switches between fingerprint sensing mode and touch sensing mode based on operational context. The controller determines whether to process fingerprint data or touch input data from the fingerprint sensor, allowing the same sensor to serve dual purposes without conflict. This dynamic mode switching resolves the contradiction by temporally separating the two functions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters (sensing mode) based on contextual requirements. When authentication is needed, the fingerprint sensor operates in fingerprint mode with specific signal processing parameters; when device control is needed, it switches to touch mode with different parameters. This parameter change allows accurate differentiation despite physical proximity.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the fingerprint sensor operates in both fingerprint sensing and touch sensing modes, then sensor versatility is improved, but system complexity increases

Engineering Contradiction:
Improvesensor versatilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The fingerprint sensor is designed to perform multiple functions: fingerprint authentication and touch input detection. By making the sensor universal, the system reduces the need for separate components while maintaining both functionalities. The controller intelligently determines which function to activate based on operational context.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the existing fingerprint sensor infrastructure to serve dual purposes without requiring additional dedicated hardware. The same sensor array and basic processing circuitry handle both fingerprint and touch inputs, with the controller self-managing the mode switching based on operational needs.

Inventive Principle:
Principle #25Self-service

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 enhances touch detection accuracy and usability by allowing the fingerprint sensor to seamlessly integrate with touch sensors, improving user authentication and device control functionality.

Implementation Method 1

capacitive sensors capable of determining presence and location of a touch and capable of determining a fingerprint pattern

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Data Source

PatentEP3480685B1Electronic device including touchpad and fingerprint sensor and method of detecting touch
Publication Date: 2023.04.19 BLACKBERRY LTD
  • EP3480685B1 patent drawingFigure 1
  • EP3480685B1 patent drawingFigure 2A~2B
  • EP3480685B1 patent drawingFigure 3

AI summary

A method for controlling an electronic device having a first touch sensor array and a fingerprint sensor includes receiving a first touch at the fingerprint sensor, in a fingerprint sensing mode: receiving first touch data associated with the first touch to a fingerprint controller, and authenticating a user based on the first touch data, and in a touch sensing mode: transmitting the first touch data associated with the first touch to a second controller, wherein the fingerprint sensor and the first touch sensor array form a combined touchpad in the touch sensing mode, and determining a touch location on the combined touchpad based on the first touch data.