Scanning Ophthalmoscope Illumination Control via Mirror Motion Feedback
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Solution Overview
Problem
Ophthalmic imaging scanners face challenges in ensuring patient safety by preventing exposure to excessive radiation levels during imaging, as existing safety mechanisms may fail to detect deviations in beam delivery, potentially leading to unsafe illumination conditions.
Innovation Solution
An ophthalmic imaging instrument equipped with a rotatable mirror and a rotary encoder that generates a signal indicative of its rotational motion, allowing a processor to detect deviations from a predetermined motion and generate control signals to reduce or halt illumination, using a power supply or shutter to ensure safe exposure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotary encoder and processor are added to detect mirror rotation deviations, then patient safety is improved, but device complexity increases
Solution Approach 1:
The rotary encoder continuously monitors the actual rotational position of the scanning mirror before the beam reaches the patient's eye. The processor compares this actual position with the expected position from control signals, enabling early detection of any deviations in mirror rotation that could lead to unsafe illumination conditions.
Solution Approach 2:
A feedback loop is established where the rotary encoder provides real-time position data to the processor, which then generates control signals to the light source or shutter. When a deviation is detected, the system immediately adjusts the illumination to prevent excessive exposure, creating a closed-loop safety mechanism.
2Reliability
If real-time monitoring of beam delivery is implemented, then safety is improved, but use of energy increases
Solution Approach 1:
The monitoring system uses a rotary encoder that detects rotational position at specific intervals rather than continuous measurement. The processor only activates safety control actions when deviations are detected, rather than continuously adjusting parameters. This partial monitoring approach provides adequate safety while reducing energy consumption compared to continuous full-system monitoring and 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
The system effectively reduces the risk of eye damage by detecting and responding to deviations in rotational motion, ensuring safe illumination levels and preventing excessive exposure to radiation.
Implementation Method 1
a rotary encoder coupled to the rotatable mirror so as to generate a signal indicative of a rotational motion of the rotatable mirror
Implementation Method 2
a processor arranged to: detect when the rotational motion of the rotatable mirror indicated by the signal has deviated from the predetermined rotational motion
Data Source
AI summary
An ophthalmic imaging instrument for imaging an eye of a subject, comprising: a light source arranged to emit a beam of light for imaging the eye; an optical system comprising a rotatable mirror and a drive mechanism arranged to drive the rotatable mirror to undergo a predetermined rotational motion to scan the beam of light across the eye; a rotary encoder coupled to the rotatable mirror so as to generate a signal indicative of a rotational motion of the rotatable mirror; and a processor arranged to detect when the rotational motion of the rotatable mirror indicated by the signal has deviated from the predetermined rotational motion and, in response to detecting that the rotational motion of the rotatable mirror has deviated from the predetermined rotational motion, generate a control signal to reduce an illumination of the eye by the beam of light.