Fingerprint Touch Sensor Electrode Segmentation

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Solution Overview

Problem

As screens on mobile devices enlarge and bezels minimize, there is a need for a fingerprint recognition technology that can integrate with touch screens without compromising touch sensing capabilities, particularly in ensuring appropriate driving frequencies for both touch and fingerprint sensing while maintaining linearity of touch sensing.

Innovation Solution

A fingerprint and touch sensor design that includes a touch sensing area and a fingerprint-touch sensing area, where the latter integrates fingerprint recognition electrodes electrically separated from touch electrodes, allowing for simultaneous touch and fingerprint sensing with optimized electrode arrangements and wiring to reduce resistance and parasitic capacitance, enabling efficient driving frequencies for both touch and fingerprint sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If fingerprint recognition electrodes are integrated with touch electrodes in the same area, then both fingerprint recognition and touch sensing can be performed on the entire screen, but the driving frequency for fingerprint sensing cannot be secured and touch sensing linearity is lost

Engineering Contradiction:

Improvefingerprint recognition capabilityVSAvoidtouch sensing linearity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The sensor is divided into two distinct sensing areas: a touch sensing area with touch electrodes for touch detection, and a fingerprint-touch sensing area with fingerprint electrodes for fingerprint recognition. This segmentation allows each area to be optimized for its specific function, maintaining touch sensing linearity while enabling fingerprint recognition capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different electrode arrangements and intervals are applied to different areas of the sensor. The fingerprint-touch sensing area has a first interval optimized for fingerprint recognition, while the touch sensing area has a second interval optimized for touch sensing linearity. This local differentiation resolves the contradiction between achieving fingerprint recognition and maintaining touch sensing quality.

Inventive Principle:

Principle #3Local quality

2Speed

If fingerprint electrodes and touch electrodes are electrically separated, then driving frequency for fingerprint sensing can be secured, but device complexity increases

Engineering Contradiction:

Improvedriving frequencyVSAvoidelectrode arrangement complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The fingerprint electrodes and touch electrodes are arranged in the same physical sensor structure and share common wiring paths where possible. The fingerprint electrodes extend into the touch sensing area and are electrically connected to the same terminal structures, reducing the need for separate wiring and lowering overall device complexity while maintaining electrical separation for independent driving.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The sensor structure serves multiple functions: the fingerprint electrodes can be used for both fingerprint recognition and touch sensing (as touch sensing nodes), while the touch electrodes are used for touch sensing. This multi-functionality reduces the need for completely separate systems and lowers device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 design ensures smooth operation of both touch and fingerprint sensing on the entire screen, maintaining linearity of touch sensing while achieving sufficient driving speeds for fingerprint recognition, thus enhancing user convenience and operational efficiency.

Implementation Method 1

a first fingerprint electrode and a second fingerprint electrode are arranged and electrically separated from the first touch electrode and the second touch electrode, the first fingerprint electrode and the second fingerprint electrode being configured to provide fingerprint sensing nodes at which a fingerprint is recognized

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

a first touch electrode and a second touch electrode are arranged to provide touch sensing nodes at which touch sensing is performed

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11398107B2Fingerprint-touch combined sensor and electronic device including the same

Publication Date: 2022.07.26 SAMSUNG ELECTRONICS CO LTD

AI summary

A sensor for recognizing a fingerprint and sensing a touch is provided. The sensor includes a touch sensing area in which a first touch electrode and a second touch electrode are arranged to provide touch sensing nodes at which touch sensing is performed; and a fingerprint-touch sensing area comprising a fingerprint recognition area in which a first fingerprint electrode and a second fingerprint electrode are arranged and electrically separated from the first touch electrode and the second touch electrode, the first fingerprint electrode and the second fingerprint electrode being configured to provide fingerprint sensing nodes at which a fingerprint is recognized in a fingerprint recognition mode, wherein in the fingerprint recognition area, a portion of the first fingerprint electrode and the second fingerprint electrode is used for fingerprint recognition and, as the touch sensing nodes, the touch sensing.