Polarization Fundus Camera Suppressing Internal Reflection
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Solution Overview
Problem
Conventional fundus cameras struggle to capture clear images of choroidal vessels and lesions due to the absorption of visible light by melanin pigment, leading to high costs and limited accessibility of near-infrared imaging devices, which are expensive and have low resolution.
Innovation Solution
A polarization fundus camera using near-infrared light between 650 to 700 nm, combined with a narrowband optical filter and polarization beam splitter, reduces manufacturing costs and enhances image clarity by filtering out internal reflections, allowing for wide-angle fundus photography without direct pupil illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If near-infrared light source of 800 nm or more is used to image choroid, then choroidal vessels and lesions can be identified, but the equipment becomes expensive and low in demand
Solution Approach 1:
The patent changes the wavelength parameter of the light source from conventional 800 nm or more near-infrared to 650-700 nm near-infrared, which can penetrate melanin pigment effectively while using commercially available light sources and imaging devices, thereby reducing manufacturing costs while maintaining choroidal imaging capability
Solution Approach 2:
The patent employs commercially available visible light light sources, standard optical components, and conventional imaging devices instead of specialized near-infrared components, making the system more affordable and accessible for widespread clinical use
2Measurement precision
If near-infrared light source is used, then choroidal imaging is possible, but optical design and coating become complex and expensive
Solution Approach 1:
By changing the light wavelength to 650-700 nm, the patent enables the use of standard optical components with conventional coatings designed for visible light, eliminating the need for specialized near-infrared optical designs and expensive wavelength-specific coatings
3Ease of manufacture
If conventional visible light fundus camera is used, then equipment cost is low, but choroidal vessels and lesions cannot be clearly identified due to melanin absorption
Solution Approach 1:
The patent changes the illumination light wavelength to 650-700 nm near-infrared range, which has lower absorption by melanin pigment compared to visible light, enabling clear choroidal imaging while maintaining compatibility with conventional optical components and affordable equipment
4Device complexity
If internal reflection is not suppressed, then simple optical design is possible, but image quality deteriorates due to reflection artifacts
Solution Approach 1:
The patent introduces a polarization beam splitter as an intermediary component that separates the illumination light path from the imaging light path, effectively suppressing internal reflections and improving image quality while maintaining a relatively simple overall optical design
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
The solution enables cost-effective, high-resolution imaging of choroidal vessels and lesions, increasing diagnostic value and accessibility of fundus photography for both mydriatic and non-mydriatic cameras, reducing medical treatment costs and side effects.
Implementation Method 1
a narrowband optical filter 90 having a band of 12 nm or less for the light passing through the linear polarization filter 80 and filtering the light emitted from the polarization beam splitter 50
Implementation Method 2
a polarization beam splitter 50 transmitting P polarized light and reflecting S polarized light from the light introduced from the mirror 40
Implementation Method 3
a linear polarization filter 80 through which only the P polarized light passes
Implementation Method 4
an objective lens 60 enlarging an image of a fundus formed by the light introduced from the polarization beam splitter 50
Data Source
AI summary
Disclosed is a polarization fundus camera including: an illumination unit emitting light; a diffusion lens; an illumination lens irradiating the light introduced from the diffusion lens; a mirror reflecting light introduced from the illumination lens; a polarization beam splitter; an objective lens enlarging an image of a fundus formed by the light introduced from the polarization beam splitter; a short-range eyepiece lens reducing an image of the fundus enlarged by the objective lens; a linear polarization filter; a narrowband optical filter; and an imaging device.