Slit-Scanning Fundus Imager With Moving Reflex-Blocking Zones
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Solution Overview
Problem
Existing scan imagers, particularly fundus scan imagers, suffer from reflexes at internal system lenses, which current techniques like pupil splitting fail to fully eliminate, leading to image artifacts and reduced field of view.
Innovation Solution
Implement a radiation-blocking and collector-blocking component positioned at conjugate planes of target optics within the scan imager to create moving non-illumination and non-collection zones, respectively, to block overlap between illumination and collection regions, thereby reducing reflex artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If pupil splitting is used to reduce reflexes, then some reflex reduction is achieved, but reflex artifacts remain and field of view is limited
Solution Approach 1:
The patent segments the optical path by introducing separate illumination and collection apertures at conjugate planes, dividing the single aperture into two distinct functional openings that prevent overlap between illumination and collection paths, thereby eliminating reflex artifacts while maintaining full field of view
Solution Approach 2:
The patent introduces conjugate plane apertures as intermediary elements between the illumination source and the sample, and between the collector and the sample. These intermediary apertures act as mediators that selectively control light paths, allowing illumination light to pass while blocking reflected light from reaching the collector
2Object-affected harmful factors
If radiation-blocking components are added to eliminate reflexes, then image quality improves, but device complexity increases
Solution Approach 1:
The patent merges the reflex blocking function with the existing aperture structure by positioning the illumination and collection apertures at conjugate planes. This integration allows the apertures to serve dual purposes: controlling the field of view and eliminating reflexes, thereby reducing the need for separate blocking components
Solution Approach 2:
The patent uses optical conjugate planes to create virtual copies of the aperture structure at different locations in the optical path. By placing apertures at conjugate planes, the system creates replicated aperture structures that block reflexes without requiring additional physical blocking components in the direct light path
3Measurement precision
If focus adjustment is made for extreme myopia, then imaging capability is maintained, but image brightness decreases
Solution Approach 1:
The patent performs preliminary action by pre-positioning the illumination and collection apertures at conjugate planes before light reaches the sample. This preliminary configuration ensures that the apertures are optimally positioned to maximize light transmission for extreme myopic eyes while maintaining focus accuracy, preventing brightness loss during focus adjustment
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
Effectively minimizes reflex artifacts at target optics, enhancing image quality and maintaining focus adjustments while allowing for brighter images in extreme cases, such as highly myopic eyes.
Implementation Method 1
A radiation-blocking component may be positioned to partially block the radiation stream output from the radiation source and to limit the radiation received by the scanning component
Implementation Method 2
The scanning component receives a radiation stream (e.g., laser beam or light beam) from the radiation source, and defines a scan beam (e.g., by rotation of a deflecting mirror within the galvanometer). The scan beam may be scanned across the sample to be imaged
Implementation Method 3
A collector (e.g., a photodetector, photo-sensor, charge coupled device (CCD) image sensor, or complementary metal-oxide-semiconductor (CMOS) image sensor) for collecting scattered radiation (e.g., scattered light) returning from the sample
Implementation Method 4
A collector-blocking component may be positioned to partially block the collection region so as to block the amount of returning, scattered radiation that reaches the collector
Data Source
Figure 1~2
Figure 3~5C
Figure 6A~6B
AI summary
A scan imaging system has a scanning component that receives light from a light source, and creates a scanning beam that is directed by an optic train to a sample to be imaged. A camera captures light returning from the sample to construct an image. Reflexes on a target lens within the optic train are prevented by one or more light blocks. A first light block,imaged to the target lens,is positioned in alight path from the light source to the scanning component to create a first moving dark zone on the target lens through which the scanning beam from the scanning component to the sample may not pass. A second light block, also imaged to the target lens, is positioned in alight path from the sample to the collector to create a second moving dark zone on the target lens through which light returning from the sample may not pass. The moving dark zones maintain the scanning beam separate from the returning light on the target lens.