Ophthalmologic Imaging Optical Unit Fixation Target Recognition
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Solution Overview
Problem
Ophthalmologic imaging apparatuses using OCT struggle with proper fixation due to the shifting image-formation position of fixation light when attachments are applied, which affects the subject's ability to recognize a fixation target clearly.
Innovation Solution
An optical unit is introduced that includes a lens for changing the focus position of measurement light and a joining member to converge light from a second light source into the optical path of the measurement light, allowing for proper fixation regardless of the use or non-use of an attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an attachment (optical unit) is applied to change focus position from fundus to anterior eye part, then the measurement capability for anterior eye part is improved, but the fixation target recognition is deteriorated due to shifting image-formation position
Solution Approach 1:
The optical system is segmented into separate optical paths: one for measurement light (OCT) and one for fixation light. The attachment (optical unit) is selectively insertable into only the measurement light optical path, leaving the fixation light optical path unaffected. This segmentation allows the attachment to improve anterior eye part measurement capability while preventing degradation of fixation target recognition accuracy.
2Device complexity
If a common objective lens is used for both measurement light and fixation light, then the device complexity is reduced, but the reliability of fixation is deteriorated when attachment is applied
Solution Approach 1:
A beam splitter (joining member) is introduced as an intermediary element that directs measurement light and fixation light into separate optical paths. This allows the attachment to be inserted into the measurement light path without affecting the fixation light path, thereby maintaining fixation reliability while enabling versatile measurement capability.
3Adaptability or versatility
If the optical unit is made detachable for versatility, then the adaptability is improved, but the device complexity increases due to additional joining and removal mechanisms
Solution Approach 1:
The optical unit is designed with universal mounting interfaces that can be attached and detached from the main body apparatus using standardized joining members. This multi-functional design allows the same optical unit to be selectively mounted for anterior eye part measurements and removed for fundus measurements, providing versatility without requiring complex custom mechanisms for each measurement type.
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 clear recognition of a fixation target and proper fixation without regard to the attachment's impact on the image-formation position, ensuring effective OCT imaging.
Implementation Method 1
a lens that is locatable in an optical path of measurement light and used for changing a focus position of measurement light from a first site of the eye to a second site
Implementation Method 2
a joining member that joins an optical path from a second light source to the optical path of measurement light, wherein the optical unit converges light from the second light source having been guided into the optical path of measurement light
Implementation Method 3
an optical system that splits light from a first light source into measurement light and reference light and detects interference light of returned light of measurement light from an eye and reference light
Data Source
AI summary
An optical system of an ophthalmologic imaging apparatus of embodiment splits light from a first light source into measurement light and reference light and detects interference light of returned light of measurement light from an eye and reference light. An image forming part forms an image based on detection result from the optical system. The optical unit includes a lens and joining member. The lens is locatable in an optical path of measurement light and used for changing a focus position of measurement light from a first site of the eye to second site. The joining member joins an optical path from a second light source to the optical path of measurement light. The optical unit converges light from the second light source having been guided into the optical path of measurement light by the joining member on an eye fundus via the lens.