OCT Device Two-Dimensional Scanning for Precise Measurement

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Solution Overview

Problem

Conventional optical image measurement devices face challenges in accurately setting measurement ranges and acquiring images at desired timings, particularly for fine structures and living organisms that change over time.

Innovation Solution

The device enables repetitive scanning along designated cross-section positions, forming tomographic images, and displaying a tomographic motion image to allow precise measurement range setting and timely image acquisition by using a combination of Galvano mirrors and a control system that controls the low-coherence light source and reference mirror for real-time image processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a conventional optical image measurement device scans with a light beam only in one direction orthogonal to the depth direction, then the device complexity is reduced, but the measurement precision and ability to set accurate measurement ranges deteriorates

Engineering Contradiction:
Improvescanning system complexityVSAvoidmeasurement range setting accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces a second scanning dimension by adding a second Galvano mirror that scans the light beam in the vertical direction (y-direction) while the first Galvano mirror scans in the horizontal direction (x-direction). This two-dimensional scanning capability enables precise positioning and setting of measurement ranges in both horizontal and vertical directions, resolving the contradiction by sacrificing some device complexity to achieve significantly improved measurement precision and range setting accuracy.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Speed

If the device scans only in one direction to form 2D tomographic images, then the scanning speed is maintained, but the ability to capture images at desired timings and observe temporal changes deteriorates

Engineering Contradiction:
Improvescanning speedVSAvoidtiming flexibility for image acquisition
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The patent implements dynamic scanning control where the scanning system can adaptively adjust scanning patterns, pause at specific positions, and repeat scans at designated cross-sections based on real-time observation needs. The control unit enables flexible timing control, allowing the system to capture images at desired moments while maintaining overall scanning efficiency, thus resolving the contradiction between scanning speed and timing flexibility.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the device uses a single scanning pattern, then the ease of operation is improved, but the adaptability to different measurement requirements and objects deteriorates

Engineering Contradiction:
Improveoperation simplicityVSAvoidmeasurement range adaptability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal scanning system that can perform multiple scanning patterns (horizontal, vertical, diagonal, circular, etc.) using the same hardware configuration of two Galvano mirrors. The control unit provides automated selection and execution of different scanning patterns based on measurement requirements, maintaining ease of operation while achieving high adaptability to various measurement objects and requirements through software-controlled versatility.

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 approach allows for highly accurate setting of measurement ranges and acquisition of images at desired times, enhancing the precision and timing of image capture in medical applications like ophthalmology.

Implementation Method 1

the intensity of a light caused by interference of light fluxes from the measuring arm and the reference arm is analyzed by a spectrometer

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

a beam of a low-coherence light is applied to a measurement object

Methodology Applied
Scientific EffectOptical coherence: Coherent Light

Implementation Method 3

a measuring arm scans an object by using a rotary deflection mirror (Galvano mirror)

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 4

obtaining the spectrum intensity distribution of the reflected light

Methodology Applied
Scientific EffectSpectroscopy: Absorption Spectroscopy

Implementation Method 5

subjecting the obtained distribution to Fourier transform

Methodology Applied
Scientific EffectFourier transform:

Data Source

PatentEP2138825B1Optical image measurement instrument
Publication Date: 2014.11.12 TOPCON CORPORATION
  • EP2138825B1 patent drawingFigure 1
  • EP2138825B1 patent drawingFigure 2
  • EP2138825B1 patent drawingFigure 3

AI summary

A device 1 is an OCT device that splits a low-coherence light L0 into a signal light LS and a reference light LR, detects an interference light LC obtained by superimposing the signal light LS propagated through an eye E and the reference light LR propagated through a reference mirror 174, and forms an image of an fundus oculi Ef. The device 1 has a scan unit 141 that scans the eye E with the signal light LS. When a cross-section position is designated in an fundus oculi image Ef', the device 1 repetitively scans with the signal light LS along each cross-section position to repeatedly forms tomographic images at each cross-section position, thereby displaying a tomographic motion image at each cross-section position on a display 240A. An operator can observe the tomographic motion image to designate the range and timing for measurement of a tomographic still image.