Biometric Scanner Delay Layer Ultrasonic Clarity

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Solution Overview

Problem

Existing ultrasound-based fingerprint scanning systems face difficulties in obtaining clear images due to the same device being used for both generating and detecting ultrasound energy, leading to reduced clarity and accuracy.

Innovation Solution

A biometric scanner is designed with a separate ultrasonic plane wave generator and detector array, featuring a delay layer between them, utilizing a hydrophone array and piezoelectric film, and control electronics to manage energy pulses and reflected signals, allowing for improved image clarity and resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the same device is used to generate and detect ultrasound energy, then device complexity is reduced, but image clarity and measurement precision deteriorate

Engineering Contradiction:

Improvedevice complexityVSAvoidimage clarity

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The device is segmented into separate functional components: an ultrasonic plane wave generator and an ultrasonic detector array. This segmentation allows each component to be optimized for its specific function, with the generator focused on producing clean plane waves and the detector focused on capturing reflected signals, thereby improving image clarity while maintaining reasonable overall system complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A delay layer is introduced as an intermediary component between the ultrasonic generator and the detector array. This delay layer serves as a mediator that prevents direct coupling between the generator and detector, eliminating interference and allowing clear separation of the transmitted and received signals, which directly improves measurement precision and image clarity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a separate detector array is introduced, then image clarity improves, but device complexity increases

Engineering Contradiction:

Improveimage clarityVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The detector array elements are designed to perform multiple functions: detecting ultrasonic signals, providing electrical insulation, and contributing to the overall structural integrity of the device. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while maintaining improved image clarity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The use of thin film insulating substrates and flexible detector element designs allows for a compact integration of the detector array. This approach minimizes the space required for the additional components and reduces the overall structural complexity, making the separate detector array design more practical and manageable.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If a delay layer is placed between generator and detector, then signal interference is reduced, but device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvesignal interference reductionVSAvoidease of manufacture

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The delay layer is constructed from homogeneous acoustic coupling material that provides consistent signal transmission properties throughout. This homogeneity ensures uniform delay characteristics across the entire layer, simplifying the manufacturing process by eliminating the need for complex variable-depth structures or multiple material interfaces, thereby improving ease of manufacture while maintaining reliable signal interference reduction.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The delay layer utilizes composite material structures that combine acoustic coupling properties with electrical insulation capabilities in a single integrated layer. This composite approach eliminates the need for separate acoustic and electrical insulation layers, reducing manufacturing steps and simplifying the overall device construction while maintaining the desired signal interference reduction.

Inventive Principle:

Principle #40Composite materials

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

The solution enables high-resolution imaging of fingerprints with improved clarity and reliability, capable of handling large areas and providing a competitive advantage over existing systems by optimizing ultrasound pulse generation and detection processes.

Implementation Method 1

The ultrasound method employs a piezoelectric transducer that sends a longitudinal wave or pulse through an acoustic transmitting media

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

there is a layer of material which delays movement of the energy. The delay layer resides in the path of the ultrasound energy

Methodology Applied

Scientific EffectAcoustic wave propagation delay: Speed of Sound

Implementation Method 3

The pulse reflected back to the sensing element may be used to measure the distance traveled by the pulse

Methodology Applied

Scientific EffectPiezoelectric effect: Converse Piezoelectric Effect

Data Source

PatentUS8201739B2Biometric sensor with delay layer

Publication Date: 2012.06.19 QUALCOMM INC

AI summary

A biometric scanner is described and claimed. The scanner has a platen, an ultrasonic plane wave generator, an ultrasonic detector, and a delay layer residing between the generator and the detector.