Phase Modulation Device for Ophthalmic Instruments
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Solution Overview
Problem
Current ophthalmic instruments face challenges in implementing adaptive optics in closed-loop systems without causing patient discomfort, managing aberrations, and maintaining calibration accuracy due to temperature drifts and non-linearities in phase modulators, especially when simulating visual corrections or performing retinal imaging.
Innovation Solution
A phase modulation device that uses a secondary light beam to calibrate and control the phase modulation of the main light beam without illuminating the patient's eye, allowing for periodic calibrations and aberration control, using a deformable mirror and wavefront analysis to set actuator motions and record responses, ensuring accurate modulation setpoints despite temperature and non-linear issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a closed-loop adaptive optics system uses a main light beam to correct eye aberrations, then the wavefront can be corrected, but the patient experiences visual discomfort and glare
Solution Approach 1:
The patent divides the optical system into two separate beams: a main beam for visual stimulation and a secondary beam for wavefront measurement and calibration. The secondary beam is directed through the deformable mirror to a wavefront analyzer, allowing the system to measure and correct aberrations without the patient experiencing discomfort from the measurement process itself.
Solution Approach 2:
The patent introduces a secondary light beam as an intermediary that carries the wavefront information through the deformable mirror to the wavefront analyzer. This intermediary beam enables the system to indirectly measure and correct aberrations without directly impacting the patient's visual comfort during the correction process.
2Measurement precision
If the system uses an artificial eye for calibration, then the optical system aberrations can be measured, but the alignment and optical quality requirements are extremely high
Solution Approach 1:
The patent uses a secondary light beam as a copy or replica that traverses the same optical path through the deformable mirror as the main beam would. This secondary beam allows the system to calibrate and measure aberrations without requiring a complex artificial eye, simplifying the calibration process while maintaining measurement accuracy.
3Reliability
If phase modulation means are used to correct wavefront, then aberrations can be compensated, but temperature drift and non-linearities degrade calibration accuracy
Solution Approach 1:
The patent implements a feedback mechanism where the wavefront analyzer continuously measures the wavefront after it passes through the deformable mirror, and the control unit adjusts the phase modulation to compensate for temperature drift and non-linearities. This closed-loop feedback maintains calibration accuracy despite environmental variations.
Solution Approach 2:
The patent monitors and compensates for parameter changes in the phase modulation means, particularly temperature variations. The control unit adjusts the phase modulation parameters in real-time to compensate for temperature drift and non-linearities, maintaining accurate wavefront correction throughout the operating range.
Data Source
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AI summary
The invention relates to a phase modulation device implemented in an ophthalmic instrument that uses a main light beam (FA) interacting with an eye (EYE), said device comprising: means (MD) for modulating the phase of the wave front of said main light beam (FA); means for controlling the phase modulation means according to a modulation set-point; and means for analysing the modulation thus carried out of the wave front of the main light beam (FA). The device further includes means for emitting a secondary light network (FC), means for directing the secondary light network (FC) along an optical path to the modulation means and then to the wave front analysis means, said optical path extending through the eye. The control means and the front wave analysis means receiving the modulated secondary light beam (FC) interact during a so-called training period in order to provide response data of the phase modulation means to a set of pre-determined modulation set-points.