Ophthalmic Device Nose Collision Avoidance
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Solution Overview
Problem
Conventional ophthalmic devices face challenges in aligning the examination head with the subject's eye, particularly when using large objective lenses, leading to a short operating distance that can result in the head coming too close to the subject's nose, especially due to variations in nose shape and size.
Innovation Solution
The ophthalmic device employs a displacement mechanism with a rotation mechanism to adjust the examination head's position and distance, using a distance detecting unit to avoid the nose by rotating the head when the detected face distance is less than a threshold, and includes movement mechanisms for precise alignment and retraction control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If an objective lens with larger diameter is used to support wide-angle photographing, then the photographic angle of view is improved, but the operating distance becomes shorter causing the examination head to come close to the subject's nose
Solution Approach 1:
The patent introduces dynamic control of the examination head's position and orientation. A displacement mechanism with multiple degrees of freedom (X, Y, Z translations and rotations) allows the system to dynamically adjust the examination head's pose. The control unit continuously monitors nose distance and automatically adjusts positioning to maintain safe clearance while preserving wide-angle imaging capability through real-time dynamic compensation rather than static geometric constraints
Solution Approach 2:
The patent implements a feedback control system using distance detection units (such as infrared sensors or cameras) that continuously measure the distance between the examination head and the subject's nose. This measured distance is fed back to the control unit, which then adjusts the displacement mechanism to maintain the distance within a predetermined safe range. This closed-loop feedback ensures that wide-angle imaging can be performed without the examination head coming too close to the subject's nose
2Speed
If automatic alignment is executed with a short operating distance, then alignment speed is improved, but the likelihood of the examination head coming close to the subject's nose increases
Solution Approach 1:
The patent implements a feedback control system using distance detection units (such as infrared sensors or cameras) that continuously measure the distance between the examination head and the subject's nose. This measured distance is fed back to the control unit, which then adjusts the displacement mechanism to maintain the distance within a predetermined safe range. This closed-loop feedback ensures that wide-angle imaging can be performed without the examination head coming too close to the subject's nose
Solution Approach 2:
The patent applies preliminary anti-action by proactively preventing the examination head from approaching too close to the nose. The control unit uses predetermined safe distance thresholds and actively counteracts the tendency of the alignment mechanism to move the head too close by introducing compensatory displacement. This preventive approach eliminates the need for reactive measures while maintaining fast alignment throughput
Data Source
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AI summary
There are provided an ophthalmic device capable of reliably avoiding an examination head coming closer to a nose of a subject and a method for operating the ophthalmic device. The ophthalmic device includes a displacement mechanism (an XZ movement mechanism (16), a Y movement mechanism (18), a swing rotation mechanism (20), and a tilt rotation mechanism (80)) configured to displace an examination head (22) with respect to a subject eye (E), a drive controlling unit (46) configured to drive the displacement mechanism to displace the examination head (22) to an examination position for the subject eye (E) along an axis (TA) of tilt, a distance detecting unit (a stereo camera (34) and a detection controlling unit (47A)) configured to detect a face distance (Fd) which is a distance between the examination head (22) and a face of a subject while the examination head (22) is displaced along the axis (TA) of tilt by the displacement mechanism, and a retraction controlling unit (47B) configured to drive the displacement mechanism to rotate the examination head (22) in a direction of increasing the face distance (Fd) around a rotation axis determined in advance when the face distance (Fd) detected by the distance detecting unit is less than a threshold determined in advance.