Wide-Angle Lens Attachment for Fundus Camera
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fundus photographing apparatuses face challenges in achieving a wide view angle due to a short working distance and difficulty in opening the examinee's eyelid, especially when using a wide-angle lens attachment that requires a lower chief ray height, which limits the imaging view angle and complicates aberration correction.
Innovation Solution
A fundus photographing apparatus with a wide-angle lens attachment that includes a second objective optical system forming a second pivot point, allowing the laser beam to bend at a higher position than the chief ray height, thereby increasing the imaging view angle and maintaining a sufficient working distance, while also incorporating a diopter correcting lens to manage diopter changes and reduce aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a wide-angle lens attachment is placed between the single pivot point and the inspection window to widen the imaging view angle, then the imaging view angle is improved, but the working distance becomes shorter and it becomes difficult to open the examinee's eyelid
Solution Approach 1:
The patent divides the objective optical system into two separate systems: a first objective optical system forming a first pivot point, and a second objective optical system forming a second pivot point. This segmentation allows each system to be optimized independently, enabling the second system to bend the laser beam at a higher position while maintaining adequate working distance through the first system's pivot point configuration
Solution Approach 2:
The patent introduces a second pivot point in addition to the first pivot point, adding another dimensional parameter for beam manipulation. By creating a second pivot point through the wide-angle lens attachment, the system gains an additional degree of freedom to control beam path geometry, allowing the beam to be bent at a higher position without compromising working distance
2Area of stationary object
If the chief ray height of the laser beam entering the wide-angle lens is lowered to widen the imaging view angle, then the imaging view angle is improved, but the working distance becomes shorter
Solution Approach 1:
The patent segments the beam bending function between two objective optical systems. The first objective optical system handles initial beam direction, while the second objective optical system (wide-angle lens attachment) performs additional bending. This segmentation allows the second system to operate with higher chief ray height, maintaining working distance while achieving wide-angle imaging
3Area of stationary object
If a single pivot point is used to scan the laser beam on the fundus, then the system structure is simple, but the imaging view angle cannot be widened without compromising working distance
Solution Approach 1:
The patent divides the objective optical system into two separable systems: a first objective optical system that can be detached, and a second objective optical system in the form of a detachable wide-angle lens attachment. This segmentation allows the base system to remain simple while enabling wide-angle capability through optional attachment of the second system
Solution Approach 2:
The patent creates a dynamic configuration where the wide-angle lens attachment can be attached or detached based on imaging requirements. When attached, the second objective optical system forms a second pivot point to enable wide-angle imaging; when detached, the system reverts to the simpler single pivot point configuration, maintaining ease of operation
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
The solution enables favorable imaging of a fundus with a wide view angle, ensuring a longer working distance and simplifying the switching of view angles without detaching the objective lens, while maintaining image quality and dust prevention.
Implementation Method 1
the second objective optical system includes at least a lens placed to bend the laser beam toward an optical axis of the second objective optical system
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A fundus photographing apparatus (1) includes: a scanning part (15) configured to change a traveling direction of a laser beam emitted from a light source (11) to scan the laser beam on a fundus (Er); and a first objective optical system (16) placed between an examinee's eye (E) and the scanning part to form a first pivot point (P) about which the laser beam delivered from the scanning part is caused to pivot in association with operation of the scanning part, the fundus photographing apparatus being configured to image an image of the fundus of the examinee's eye by use of light from the fundus resulting from the laser beam having passed the first pivot point and being delivered to the fundus of the examinee's eye, wherein the apparatus further includes a wide-angle lens attachment (3) attachable to a housing surface of the apparatus on a side which will face to the examinee, the housing surface having an inspection window (17), and the wide-angle lens attachment (3) being configured to widen an imaging view angle of the image of the fundus, the wide-angle lens attachment is provided with a second objective optical system (31; 230) for forming a second pivot point (Q) about which the laser beam having passed the first pivot point is further caused to pivot in association with the operation of the scanning part in an attached state where the attachment is attached to the housing surface, and the second objective optical system includes at least a lens (31a, 31b, 31c; 231, 232) placed to bend the laser beam toward an optical axis (L3) of the second objective optical system at a higher position than a chief ray height (h1) of the laser beam on the inspection window in the attached state.