Optical Image Measurement Device Depth Alignment

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Solution Overview

Problem

Conventional optical image measurement devices face challenges in easily aligning the measurement position in the depth direction of a measurement subject, particularly due to the need for precise alignment of the reference mirror and the limited measurement sensitivity at positions distant from the optical path length origin.

Innovation Solution

An optical image measurement device comprising a light source, an interference-light generator, a changer for adjusting the optical path length difference between signal and reference lights, a detector, and a controller that analyzes the signal and noise levels to adjust the path length for optimal alignment and image formation within a predetermined frame.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the reference mirror is precisely aligned to capture images at desired depth positions, then measurement precision is improved, but device complexity and alignment difficulty increase

Engineering Contradiction:
Improvedepth position alignment precisionVSAvoidreference mirror alignment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system automatically adjusts the optical path length of the reference light by moving the reference mirror based on signal level feedback, enabling self-alignment without manual intervention. The controller monitors the signal level from the detector and autonomously controls the reference mirror position to optimize measurement conditions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements a feedback mechanism where the detector measures the signal level of interference light, the analyzer evaluates this signal level, and the controller adjusts the reference mirror position accordingly. This closed-loop feedback system continuously optimizes the optical path length difference to maintain measurement precision.

Inventive Principle:
Principle #23Feedback

2Length of stationary object

If the measurement position is distant from the optical path length origin, then deeper tissue imaging is achieved, but measurement sensitivity deteriorates

Engineering Contradiction:
Improveoptical path lengthVSAvoidmeasurement sensitivity
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The system dynamically adjusts the optical path length of the reference light to match the desired measurement depth. By making the reference arm optical path length variable rather than fixed, the system can adapt to different imaging depths while maintaining optimal measurement sensitivity through real-time controller adjustment.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If manual alignment of the reference mirror is performed, then measurement position alignment is achieved, but operation time and complexity increase

Engineering Contradiction:
Improvemeasurement position alignmentVSAvoidalignment time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs automatic self-alignment by monitoring signal levels and autonomously adjusting the reference mirror position through the controller, eliminating the need for manual alignment operations and significantly reducing setup time.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The feedback mechanism continuously monitors the signal level from the detector and automatically adjusts the reference mirror position to optimize alignment, replacing time-consuming manual alignment procedures with rapid automated feedback-controlled adjustment.

Inventive Principle:
Principle #23Feedback

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 easy alignment of the measurement position in the depth direction, ensuring accurate and clear image capture by automatically adjusting the optical path length to exceed a threshold signal level, thereby improving measurement sensitivity and image quality.

Implementation Method 1

an interference-light generator configured to generate an interference light by splitting the emitted low-coherence light into a signal light heading toward a measurement subject and a reference light heading toward a reference object, and superimposing the signal light passed through the measurement subject and the reference light passed through the reference object

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP1939579B1Optical image measurement device
Publication Date: 2018.10.31 TOPCON CORPORATION
  • EP1939579B1 patent drawingFigure 1
  • EP1939579B1 patent drawingFigure 2
  • EP1939579B1 patent drawingFigure 3

AI summary

A fundus oculi observation device acts as an optical image measurement device capable of measuring an OCT image such as a tomographic image of a fundus oculi, or the like, and is configured so as to calculate the signal level of the formed OCT image, determine whether the signal level exceeds a threshold value, and change the position of a reference mirror so that the signal level is determined to exceed the threshold value.