Optical Image Measuring Device Alignment and Focus Control

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Solution Overview

Problem

Conventional optical image measuring devices face challenges in determining the alignment, focus, and image quality, especially for non-expert users, leading to potential missed measurement timings, particularly when imaging moving subjects like the human eye.

Innovation Solution

The optical image measuring device incorporates an alignment optical system, focusing system, and tracking mechanism, which includes an alignment determination part, focus determination part, image-position determination part, image-quality determination part, and tracking determination part to ensure that all conditions are met before obtaining a tomographic image, utilizing a Fourier-Domain-type OCT method and a retinal camera unit for accurate alignment and focus adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual alignment and focus adjustment are used, then device complexity is reduced, but measurement precision and reliability deteriorate due to difficulty in determining appropriate measurement timing

Engineering Contradiction:
Improvemeasurement timing accuracyVSAvoidsystem structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The alignment determination part, focus determination part, and tracking determination part perform preliminary assessments of alignment state, focus state, and subject movement tracking before the actual measurement is executed. This ensures that measurement only proceeds when all conditions are optimal, preventing missed measurement timing while maintaining relatively simple device structure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors alignment state, focus state, and tracking state, providing feedback to the control part. Based on this feedback, the control part decides whether to execute measurement, ensuring high measurement precision without requiring overly complex device architecture.

Inventive Principle:
Principle #23Feedback

2Reliability

If multiple determination parts are added to check alignment, focus, and image quality, then measurement reliability improves, but device complexity increases

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The alignment determination part, focus determination part, image-position determination part, image-quality determination part, and tracking determination part are integrated into a unified control system that shares common hardware resources. This merging approach achieves high measurement reliability through multiple checks while avoiding proportional increases in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control part serves multiple functions: it receives inputs from all determination parts, processes alignment/focus/tracking quality assessments, and executes measurement decisions. This multi-functionality consolidates system structure while maintaining high reliability through comprehensive condition checking.

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

3Ease of operation

If automatic tracking and condition checking are implemented, then ease of operation improves, but device complexity and processing time increase

Engineering Contradiction:
Improveoperational simplicityVSAvoidcontrol system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system performs self-assessment through the alignment determination part, focus determination part, and tracking determination part, which automatically evaluate their respective conditions without user intervention. The control part then automatically decides whether to execute measurement, providing ease of operation while maintaining manageable control system complexity.

Inventive Principle:
Principle #25Self-service

4Measurement precision

If comprehensive condition checking is performed before measurement, then measurement precision improves, but loss of time increases due to multiple assessment steps

Engineering Contradiction:
Improvemeasurement timing accuracyVSAvoidpreparation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The alignment determination part, focus determination part, and tracking determination part perform preliminary condition assessments continuously or near-continuously before measurement execution. This approach ensures measurement timing accuracy by verifying all conditions are optimal while minimizing additional preparation time through efficient pre-checking.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The determination parts continuously monitor alignment, focus, and tracking states, maintaining readiness for measurement without interrupting the measurement flow. This continuous monitoring ensures measurement precision while reducing time loss by avoiding repeated setup procedures.

Inventive Principle:
Principle #20Continuity of useful action

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 configuration allows for easy and accurate measurement of moving subjects without missing the appropriate measurement timing, ensuring proper alignment, focus, and image quality, thereby enhancing the reliability of the imaging process.

Implementation Method 1

superposes the reflected light and the reference light to generate an interference light

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

acquires the spectral intensity distribution of the interference light to execute Fourier transform

Methodology Applied
Scientific EffectFourier transform:

Implementation Method 3

an interferometer is mounted at the outlet to analyze, by a spectrometer, the intensity of an interference light

Methodology Applied
Scientific EffectSpectral analysis:

Data Source

PatentEP2395343B1Optical image measuring device
Publication Date: 2018.09.05 TOPCON CORPORATION
  • EP2395343B1 patent drawingFigure 1
  • EP2395343B1 patent drawingFigure 2A
  • EP2395343B1 patent drawingFigure 2B

AI summary

An optical image measuring device includes: an optical system that generates and detects interference light; an image forming part that forms a tomographic image based on the detection; an alignment part that performs alignment of the optical system with respect to an object; a focusing part that focuses the optical system with respect to the region of interest; a determining part that determines the suitability of the position of the optical system by the alignment part, the suitability of the focus state by the focusing part, and the suitability of the position of the tomographic image in a frame; a control part that, when it is determined that all of the positions of the optical system, position of focus state and the position in said frame are appropriate, controls the optical system and the image forming part, making it possible to obtain the tomographic image of the region of interest.