Wavelength Sweeping Light Source for OCT Retinal Imaging
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Solution Overview
Problem
Optical coherence tomographic devices face challenges in detecting reflected light from a retina with an opacified crystalline lens, leading to difficulties in measuring the retina's position and axial length due to attenuated light.
Innovation Solution
An optical coherence tomographic device with a wavelength sweeping light source that adjusts its diameter and wavelength to ensure a ratio of D/S×λ>1.61, where D is the light diameter, S is the wavelength swept frequency, and λ is the center wavelength, to increase signal reception sensitivity and improve light delivery to the retina.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light with a small diameter (1-2 mm) is used to irradiate the subjected eye, then the measurement precision is maintained, but the signal strength of reflected light from the retina becomes weak when the crystalline lens is opacified
Solution Approach 1:
The patent changes the parameter of light diameter from the conventional small size (1-2 mm) to a larger size (3 mm or more). This parameter change allows sufficient light to reach the retina even when the crystalline lens is opacified, while the measurement precision is maintained through the wavelength sweeping technique and interference light analysis. The key insight is that increasing light diameter improves illumination intensity without sacrificing measurement precision when combined with the specific wavelength sweeping approach.
2Quantity of substance
If the diameter of light outputted from the light source is increased to 3 mm or more, then the amount of light reaching the retina is increased, but the device complexity increases
Solution Approach 1:
The measurement optical system is designed to serve multiple functions: it not only increases the light diameter to 3 mm or more to improve light delivery to the retina, but also maintains measurement precision through wavelength sweeping and interference analysis. This multi-functionality allows the same optical system to handle both the increased light delivery requirement and the precision measurement requirement without adding separate complex subsystems.
Solution Approach 2:
The patent employs a wavelength sweeping light source that dynamically changes the wavelength over time. This dynamic approach allows the system to use a larger light diameter (3 mm or more) for improved light delivery while maintaining measurement precision through the time-varying wavelength information. The dynamic wavelength sweeping compensates for the increased complexity by providing additional information dimensions for accurate measurement.
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 enhances signal reception sensitivity and ensures sufficient light reaches the retina, even with an opacified crystalline lens, allowing for accurate measurement of retinal position and axial length.
Implementation Method 1
a light source of wavelength sweeping type; and a measurement optical system configured to irradiate the subjected eye with light outputted from the light source
Implementation Method 2
a position of a target part in the subjected eye is specified from interference light in which the reflected light guided by the measurement optical system is combined with the reflected light guided by the reference optical system
Data Source
AI summary
An optical coherence tomographic device configured to acquire a tomographic image of a subjected eye is disclosed herein. The optical coherence tomographic device may include a light source of wavelength sweeping type; and a measurement optical system configured to irradiate the subjected eye with light outputted from the light source, where D/S×λ>1.61 may be satisfied, with a diameter of the light outputted from the light source at an incident position to the subjected eye is D, a wavelength swept frequency of the light source is S, and a center wavelength of the light outputted from the light source is λ.