Examination Instrument Glare-Free Imaging via Beam Splitter
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Solution Overview
Problem
Existing ophthalmoscopes face challenges in achieving glare-free, high-quality images with a wide field-of-view while allowing non-mydriatic imaging, as previous solutions that address reflections often impair image quality or limit the field-of-view due to increased aberrations.
Innovation Solution
The use of a polarization beam splitter and polarizers to separate the paths of illumination and imaging radiation, combined with a beam splitter design that deviates these paths by a few degrees, prevents overlap and reflections, allowing for glare-free imaging with a larger field-of-view and enabling non-mydriatic imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a black-dot conjugate method with shaped lenses is used to address reflections, then reflections are reduced, but image quality deteriorates due to increased aberrations
Solution Approach 1:
The patent divides the optical system into separate illumination and imaging paths using a beam splitter. The illumination path uses a condenser lens system while the imaging path uses a separate objective lens, allowing each path to be optimized independently without the aberrations introduced by combining them in the black-dot conjugate method
Solution Approach 2:
The patent extracts the illumination function from the imaging path by using a separate illumination source and condenser lens system. This separation allows the imaging objective to work without the aberrations caused by the black-dot conjugate method while still effectively reducing reflections through the beam splitter
2Object-affected harmful factors
If a black-dot conjugate method with shaped lenses is used to address reflections, then reflections are reduced, but field-of-view is limited
Solution Approach 1:
By segmenting the optical paths into separate illumination and imaging channels using a beam splitter, the patent allows the imaging objective to have a wider field-of-view without being constrained by the shaped lens requirements of the black-dot conjugate method. The illumination condenser can be optimized for uniform lighting while the imaging objective maximizes the visible area
Solution Approach 2:
The patent extracts the illumination function into a separate condenser lens system, freeing the imaging objective from the need to use shaped lenses. This enables the imaging path to capture a broader field-of-view while the illumination path independently manages reflection reduction through the beam splitter configuration
3Ease of operation
If undilated pupil imaging is implemented, then patient comfort is improved, but image quality deteriorates due to glare and reflections
Solution Approach 1:
The patent converts the harmful reflections from the cornea and crystalline lens into beneficial effects by using a beam splitter configured at a specific angle. The illumination path is designed to create a conjugate relationship where the beam splitter reflects illumination away from the eye while allowing imaging light to pass, effectively using the reflection mechanism to eliminate glare rather than causing it
Solution Approach 2:
By separating the illumination and imaging paths with a beam splitter, the patent enables undilated pupil imaging to produce high-quality images. The illumination condenser and imaging objective work independently, with the beam splitter ensuring that illumination reflections do not enter the imaging path, thus maintaining image quality without requiring pupil dilation
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 approach results in high-quality, glare-free images with a wider field-of-view, facilitating non-mydriatic imaging and improving the overall imaging performance by minimizing aberrations and reflections.
Implementation Method 1
The use of a polarization beam splitter and polarizers to separate the paths of illumination and imaging radiation
Data Source
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AI summary
Light from an exit pupil (112) of an illumination unit (100) is directed to abeam splitter (102) which directs the light to an objective (104).The retina (128) is illuminated, if a real image of the exit pupil (112)of the illumination unit (100) and a real image of an entrance pupil (114) of a camera unit (106) are formable in a position ranging from the cornea (120) to the backside (126) of the crystalline lens (124) with the light. The objective (104) forms a real intermediate image (130) of the retina (128) between the objective (104) and the camera unit (106). The beam splitter (102) directs the light from the retina (128) to the camera unit (106), while causing the path (134) of the illumination and the path (132) of the imaging to deviate for non- overlapping images of the exit pupil (112) and the en- trance pupil (114)in the crystalline lens (124). A relay lens system (138) forms a real image of the intermediate image (130) on a detecting component (136) with the light reflected from the retina (128) for transforming the image into an electric form to be shown on a screen (150).