Ophthalmic Apparatus Variable Optical Path Control
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Solution Overview
Problem
Existing ophthalmic photographing apparatuses face challenges in obtaining clear anterior-segment tomographic images due to improper adjustment of optical-path differences between measurement and reference light paths, often resulting in out-of-focus images or incorrect lens system identification.
Innovation Solution
An ophthalmic photographing apparatus with an interference optical system, a driving mechanism to adjust optical-path differences, and a control unit that switches between fundus and anterior-segment photographing modes by precisely positioning optical members, ensuring accurate focusing and image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the optical member is moved in a movement range similar to that at the time of photographing the fundus, then the apparatus can maintain a simple control structure, but the anterior-segment tomographic image cannot be favorably photographed (out-of-focus or lens system erroneously obtained)
Solution Approach 1:
The patent applies dynamics by making the movement range of the optical member variable based on the photographing mode. The control unit dynamically adjusts the movement range according to whether fundus or anterior-segment photographing is selected, allowing the system to adapt its behavior to different operational requirements rather than being fixed in a single configuration.
Solution Approach 2:
The patent changes the parameter of movement range based on the photographing mode. When anterior-segment photographing is selected, the control unit restricts the movement range to a smaller interval compared to fundus photographing. This parameter change ensures that the optical member is positioned accurately for anterior-segment imaging without traversing the full range used in fundus imaging, thereby preventing focus errors.
2Reliability
If the optical-path difference is adjusted using a fixed movement range, then the apparatus can operate in fundus photographing mode effectively, but it cannot obtain clear anterior-segment tomographic images
Solution Approach 1:
The patent implements multi-functionality by enabling the same OCT apparatus to perform both fundus and anterior-segment photographing effectively. The control unit achieves this by selectively adjusting the movement range of the optical member based on the selected photographing mode, allowing a single device to reliably execute different imaging functions with optimized parameters for each.
Solution Approach 2:
The system dynamically adapts its operation based on the photographing mode. When switching from fundus to anterior-segment photographing, the control unit modifies the movement range parameters, enabling the apparatus to transition between different functional states and maintain reliability across multiple imaging applications.
3Length of stationary object
If the optical member moves through a large range to accommodate fundus photographing, then the apparatus can capture deep ocular structures, but it cannot precisely focus on anterior-segment structures
Solution Approach 1:
The patent applies local quality by providing different movement range characteristics for different imaging regions. Instead of using a uniform movement range for all photographing modes, the control unit implements a restricted, smaller movement range specifically for anterior-segment photographing, optimizing the local imaging quality for anterior structures while maintaining the larger range capability for fundus imaging when needed.
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
Enables favorable photography of both fundus and anterior-segment tomographic images by accurately adjusting optical-path differences and ensuring proper mounting of the adaptor, reducing errors in image focus and lens system identification.
Implementation Method 1
the interference optical system synthesizes reflected light from the measurement optical path, which is obtained by reflection of the measurement light on the eye, with the reference light from the reference optical path, to guide the synthesized light to a detector
Data Source
AI summary
An ophthalmic photographing apparatus includes: an interference optical system including a splitter that splits light, emitted from a measurement light source, into measurement light and reference light, and synthesizing the measurement light reflected on an eye with the reference light to guide the synthesized light to a detector; a driving part that moves an optical member arranged in the optical path to adjust an optical-path difference between the measurement light and the reference light; an image obtaining part that obtains a tomographic image of a fundus or an anterior segment based on a light receiving signal output from the detector; and a driving control unit that controls driving of the driving part to locate the optical member in a predetermined position corresponding to either a photographing mode for photographing the tomographic image of the fundus or a photographing mode for photographing the tomographic image of the anterior segment.