Photoacoustic Imaging Using Multi-Angle 1D Transducer Arrays

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Solution Overview

Problem

Conventional photoacoustic imaging methods using two-dimensionally arranged electromechanical conversion elements face challenges in achieving uniform sensitivity and high signal-to-noise (SN) ratios over a wide inspection area, particularly due to cost and efficiency issues with large-scale systems and uneven sensitivity between central and peripheral elements.

Innovation Solution

A bioinformation acquisition apparatus employing a mechanically scanning electromechanical conversion element group that moves in a two-dimensional grid to receive elastic waves, allowing for high-speed signal input with uniform sensitivity and improved SN ratios by integrating a light source and conversion elements for efficient data collection across a wide area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If two-dimensionally arranged electromechanical conversion elements are used to reconstruct three-dimensional images, then image resolution and reduction of direction dependency are improved, but device complexity and cost increase due to large-scale receiving systems

Engineering Contradiction:
Improveimage resolutionVSAvoidreceiving system scale
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the two-dimensionally arranged electromechanical conversion elements into multiple one-dimensional arrays positioned at different angles around the test object. Each one-dimensional array independently reconstructs images along its detection direction, and the results are integrated to form a comprehensive three-dimensional image, thereby avoiding the need for a single large-scale two-dimensional receiving system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs multiple one-dimensional electromechanical conversion element arrays that can detect elastic waves from multiple directions. Each array serves multiple functions: detecting waves from different propagation directions and contributing to different aspects of the three-dimensional image reconstruction, thereby replacing the need for a single comprehensive two-dimensional array.

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

2Device complexity

If one-dimensionally arranged electromechanical conversion elements are used, then device complexity is reduced, but productivity decreases due to mechanical scanning requirements

Engineering Contradiction:
Improvereceiving system configurationVSAvoidimage reconstruction speed
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent uses multiple one-dimensional electromechanical conversion element arrays positioned at different angles to simultaneously detect elastic waves. This periodic arrangement allows the system to capture data from multiple directions in parallel, eliminating the need for sequential mechanical scanning and significantly improving image reconstruction speed.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent replaces the mechanical scanning system with multiple fixed one-dimensional arrays positioned at different angles. Instead of mechanically moving a single array to scan the test object, the system uses multiple stationary arrays that simultaneously detect waves from different directions, thereby eliminating mechanical movement and improving productivity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If one-dimensionally arranged electromechanical conversion elements are used, then device complexity is reduced, but measurement precision deteriorates due to sensitivity unevenness between central and end parts

Engineering Contradiction:
Improvereceiving system configurationVSAvoidsensitivity uniformity
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent positions multiple one-dimensional electromechanical conversion element arrays at different angles around the test object, creating an asymmetric detection configuration. This asymmetric arrangement ensures that elastic waves from different directions are detected by different arrays, compensating for the sensitivity unevenness inherent in individual one-dimensional arrays and achieving uniform overall sensitivity.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent assigns different one-dimensional arrays to detect elastic waves from different directional regions. Each array is optimized for its specific detection direction, and the local sensitivity characteristics of each array are compensated by the complementary coverage of other arrays, resulting in uniform overall sensitivity across the entire inspection area.

Inventive Principle:
Principle #3Local quality

4Area of stationary object

If mechanical scanning is performed to locate electromechanical conversion element groups, then coverage area is improved, but loss of time increases due to sequential positioning

Engineering Contradiction:
Improveinspection area coverageVSAvoidscanning time
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The patent uses multiple one-dimensional electromechanical conversion element arrays positioned at different angles to simultaneously detect elastic waves from different directions. This periodic arrangement allows parallel data acquisition from multiple directions, eliminating the sequential mechanical scanning process and significantly reducing the time required to cover the entire inspection area.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent divides the inspection area coverage task among multiple one-dimensional arrays positioned at different angles. Each array is responsible for detecting waves from its specific directional sector, and the results are integrated to achieve complete area coverage without requiring mechanical movement, thereby eliminating scanning time.

Inventive Principle:
Principle #1Segmentation

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-speed, uniform sensitivity, and improved SN ratio signal input over a wide inspection area, reducing the time and cost associated with large-scale systems and minimizing sensitivity unevenness.

Implementation Method 1

an electromechanical conversion element group (72), which includes a plurality of arranged electromechanical conversion elements (1), each receiving an acoustical wave, as an elastic wave, generated by the radiation of a pulsed laser light (8) to a test object (13) in a test body (6), and converting the received acoustical wave into an electric signal (9)

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The acoustical wave is generated by the radiation of the pulsed laser light to a test object in a living body to cause the thermal expansion of the test object in the internal portion of the living body

Methodology Applied
Scientific EffectPhotoacoustic effect: Photoacoustic Effect

Data Source

PatentEP3195796B1Photoacoustic imaging apparatus
Publication Date: 2020.06.03 CANON KK
  • EP3195796B1 patent drawingFigure 1~2
  • EP3195796B1 patent drawingFigure 3
  • EP3195796B1 patent drawingFigure 4~5

AI summary

A bioinforruation acquisition apparatus to input a signal having uniform sensitivity and a high SN ratio at a high speed is provided. It includes a moving device moving an element group (2) into the arrangement direction of the elements, and moves the element group situated at a first position at first time point to be situated at a second position at second time point. The element group receives an elastic wave emitted from a test object at the first time point at the first position, and the elastic wave from the test object at the second tine point at the second position. The electric signal of a specified position of a test body from a first element of the elastic waves received at the first time point and the electric signal of the specified position from a second element received at the second time point are added to each other.