Retinal Imaging Illumination Module with Perforated Mirror
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Solution Overview
Problem
Current retinal imaging devices require high operator skill and complex instrumentation, and struggle to effectively eliminate artifactual reflections from the patient's eye and lens surfaces, affecting image quality and contrast.
Innovation Solution
The retinal imaging device employs an illumination module with a light source, condenser lens, transparent plate with a light absorber, projection lenses, and a perforated mirror with a hollow cylinder to form cornea and pupil illumination doughnuts, separating illumination and imaging paths and reducing unwanted reflections, thereby creating a reflex-free image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional illumination systems are used to illuminate the fundus, then the fundus can be illuminated, but reflections from the cornea and illumination lens occur, degrading image quality
Solution Approach 1:
The illumination beam is segmented into multiple annular zones using a beam shaping element with concentric rings. This segmentation allows different zones of the illumination beam to be directed at different angles, with outer zones illuminating the fundus while inner zones are blocked, thereby eliminating corneal reflections while maintaining fundus illumination.
Solution Approach 2:
Different regions of the illumination beam are given different functions: the outer annular regions are used for fundus illumination, while the central region is blocked to prevent corneal reflections. This local differentiation of beam function resolves the contradiction between providing sufficient illumination and avoiding harmful reflections.
2Area of stationary object
If the field of view is increased to detect more eye diseases, then wider view is achieved, but the optical system complexity increases
Solution Approach 1:
The illumination module uses a single beam shaping element with concentric rings that simultaneously achieves multiple functions: it creates the doughnut-shaped illumination pattern, blocks central reflections, and provides wide-angle fundus illumination. This multi-functionality increases field of view without proportionally increasing optical system complexity.
3Ease of operation
If operator skill requirements are reduced for ease of use, then the device becomes more accessible, but achieving reflex-free imaging becomes more difficult
Solution Approach 1:
The beam shaping element with concentric rings automatically performs the function of blocking corneal reflections and shaping the illumination pattern without requiring manual adjustment by the operator. The system self-regulates the illumination geometry, reducing the skill level needed while managing the inherent complexity through a fixed 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
This configuration simplifies the optical design, reduces unwanted reflections, and achieves high-quality, reflex-free imaging, making the device easier to use and more accessible in environments with limited resources while maintaining image quality.
Implementation Method 1
a condenser lens placed at a spaced apart distance from the light source for condensing the incident beam
Implementation Method 2
at least one projection lens to focus the condensed incident beam
Implementation Method 3
a perforated mirror comprising a hollow cylinder... to yield a second partially blocked beam to form a pupil illumination doughnut
Data Source
AI summary
A retinal imaging device and illumination module. The illumination module includes a light source to provide an incident beam along an illumination axis, a condenser lens at a spaced apart distance from the light source for condensing the incident beam and emanating a condensed incident beam, a transparent plate at a spaced apart distance from the condenser lens, wherein the transparent plate comprises a light absorber, at least one projections lens system to focus the condensed incident beam, a shield at a spaced apart distance from the projection lens system to yield a first partially blocked beam to form a comea illumination doughnut, and a perforated mirror comprising a hollow cylinder. A portion of the hollow cylinder protrudes out from a reflecting face of the mirror, forming an elliptical stopper to yield a second partially blocked beam to form a pupil illumination doughnut, enabling reflex-free imaging of the retina.