Ophthalmic Apparatus Wavelength Sampling Clock

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Solution Overview

Problem

Existing ophthalmic apparatuses using optical interferometry for intraocular tomographic imaging require expensive components like fiber Bragg gratings to detect specific wavelengths, increasing costs and complexity.

Innovation Solution

An ophthalmic apparatus that generates a sample clock signal with equal frequency intervals, allowing for the determination of processing duration based on period data, enabling sampling of interference signals within the same wavelength range without the need for expensive wavelength detection components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If expensive components like fiber Bragg gratings are used to detect specific wavelengths, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvewavelength detection precisionVSAvoidapparatus complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the wavelength detection function from separate expensive components (FBG) and integrates it into the existing sample clock signal generator. The sample clock signal generator now serves dual purposes: generating sampling timing signals and detecting wavelength information through period data analysis, thereby eliminating the need for separate wavelength detection components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sample clock signal generator is designed to perform multiple functions: generating sample clock signals for interference signal sampling and simultaneously detecting wavelength information by analyzing the period data of its own output signals. This multi-functionality reduces the overall component count and system complexity while maintaining measurement precision.

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

2Measurement precision

If separate wavelength detection components are installed, then measurement precision is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improvewavelength sampling accuracyVSAvoidapparatus manufacturing ease
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the wavelength detection function with the sample clock signal generator circuit that already exists in the system. By combining these functions into a single integrated circuit, the manufacturing process is simplified as fewer separate components need to be assembled, tested, and calibrated, while still achieving accurate wavelength-based sampling.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If sampling is performed without precise wavelength range control, then productivity is improved, but measurement precision deteriorates

Engineering Contradiction:
Improvesampling speedVSAvoidwavelength range consistency
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system uses feedback from the period data of the sample clock signal to dynamically adjust and determine the processing duration for interference signal sampling. The processor analyzes the period data to identify the wavelength range, then sets the sampling duration accordingly, ensuring that sampling always occurs within the correct wavelength range while maintaining high sampling speed.

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

This configuration allows for efficient sampling of interference signals at the same timing each cycle of wavelength change, reducing costs and complexity while maintaining data processing accuracy.

Implementation Method 1

a light source of wavelength sweeping type; a measurement optical system configured to irradiate a subject eye with light from the light source

Methodology Applied
Scientific EffectWavelength sweeping:

Implementation Method 2

a light receiving element configured to receive interference light, the interference light being a combination of the reflected light from the subject eye and the reference light

Methodology Applied
Scientific EffectOptical interference: Interference

Data Source

PatentEP3674655B1Ophthalmic apparatus
Publication Date: 2022.02.23 TOMEY CORP
  • EP3674655B1 patent drawingFigure 1
  • EP3674655B1 patent drawingFigure 2
  • EP3674655B1 patent drawingFigure 3

AI summary

An ophthalmic apparatus may include: a light source of wavelength sweeping type; a measurement optical system; a reference optical system; a light receiving element that receives interference light; a sample clock signal generator that generates a sample clock signal from the light from the light source, the sample clock signal cyclically changing at equal frequency intervals; a signal processor that samples an interference signal based on the sample clock signal, the interference signal being outputted from the light receiving element when the light receiving element receives the interference light. The ophthalmic apparatus generates period data based on the sample clock signal, the period data indicating a relationship between a period of the sample clock signal and time; and determines a processing duration of the interference signal sampled at the signal processor based on the period data.