Ophthalmological Imaging Device Artifact Suppression via Phase Modulation
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Solution Overview
Problem
Existing ophthalmological imaging devices using optical coherence tomography (OCT) face challenges in removing artifacts due to reflections from objects other than the subject and coherence revival phenomena, which can degrade image quality, especially with longer coherence lengths or shorter coherence revival intervals.
Innovation Solution
An ophthalmological imaging device is designed with an interference optical system that includes an objective lens, optical scanner, and controller, where the optical scanner deflects measurement light away from the optical axis of the objective lens to minimize artifacts, and the image forming part processes interference light to produce artifact-free images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If anti-reflection coating is applied to optical members, then reflection artifacts are reduced, but it is difficult to suppress reflection perfectly and the design becomes complicated
Solution Approach 1:
The patent changes the operational parameters of the optical system by performing phase modulation on the light from the light source. This phase modulation suppresses coherence revival artifacts without requiring complex anti-reflection coatings or modifying the optical member designs, thus reducing device complexity while effectively removing artifacts
Solution Approach 2:
The patent replaces the mechanical/optical solution of applying anti-reflection coatings to optical members with a control-based solution using phase modulation of the light source. This substitution simplifies the optical system design while achieving artifact suppression
2Measurement precision
If light source with long coherence length is used, then OCT image quality is improved, but artifacts due to reflection appear more frequently
Solution Approach 1:
The patent applies phase modulation to the light source parameters, which suppresses coherence revival artifacts while maintaining the long coherence length benefits for OCT image quality. This parameter change allows using light sources with long coherence length without suffering from increased reflection artifacts
3Productivity
If light source with short coherence revival interval is used, then OCT imaging speed is improved, but coherence revival artifacts appear more frequently
Solution Approach 1:
The patent uses phase modulation of the light source to suppress coherence revival artifacts while maintaining the short coherence revival interval characteristics that enable fast OCT imaging. This allows high-speed imaging without being degraded by coherence revival artifacts
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 effectively removes artifacts near the attention site, allowing for detailed observation and improving image quality by controlling the optical scanner to deflect measurement light away from the optical axis, thereby reducing reflections and coherence revival artifacts.
Implementation Method 1
an interference optical system that divides light from a light source into measurement light and reference light, causes the measurement light to become incident on a subject's eye via an objective lens, and detects interference light between the reference light and return light of the measurement light
Data Source
AI summary
An ophthalmological imaging device according to embodiments comprises an objective lens, an interference optical system, an optical scanner, a controller, and an image forming part. The interference optical system divides light from a light source into measurement light and reference light, causes the measurement light to become incident on a subject's eye via the objective lens, and detects interference light between the reference light and return light of the measurement light that has exited from the subject's eye and passed through the objective lens. The optical scanner deflects the measurement light. The controller controls the optical scanner such that a position away from an optical axis of the objective lens is set as a center to deflect the measurement light. The image forming part forms an image of the subject's eye based on a detection result of the interference light by the interference optical system.