Image-Based Fixation Measurement Eliminates Mirror Vibrations
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Solution Overview
Problem
Existing optometry devices that use scanning laser beams for retinal birefringence measurements face challenges with vibrations, high costs, complex manufacturing, noise, and reduced lifespan due to mechanical movements, particularly when rotating tilted mirrors at high speeds.
Innovation Solution
An image-based scanning method that captures fixation information with a single image using a polarizing beam splitter, projection apparatus, convex lenses, and image sensing devices, eliminating the need for mechanical movement and rotation of optical devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a tilted mirror is rotated at high speeds to perform rapid retinal measurements, then measurement speed is improved, but vibrations increase
Solution Approach 1:
The patent extracts the harmful mechanical rotation component from the system by replacing the rotating tilted mirror with a stationary beam splitter and a rotating laser source. This separation removes the source of vibrations while preserving the functional capability of scanning light across the retina at high speeds.
Solution Approach 2:
The patent substitutes a purely mechanical system (rotating tilted mirror) with a hybrid optical-mechanical system where a stationary optical element (beam splitter) combines with a rotating laser source. This replacement eliminates mechanical vibrations from the mirror mounting while maintaining the scanning function through the rotation of the laser source instead.
2Object-affected harmful factors
If a symmetrical disk is added to balance the rotating tilted mirror, then vibrations are reduced, but device mass doubles
Solution Approach 1:
The patent removes the need for balancing masses by extracting the rotation from the mirror assembly entirely. Since the beam splitter remains stationary, no counterbalancing is required, thereby avoiding the mass penalty of adding symmetrical balancing disks.
3Adaptability or versatility
If a rotating tilted mirror system is used for scanning, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the scanning function from the tilted mirror and relocates it to the laser source rotation. The stationary beam splitter handles beam direction, simplifying the mechanical requirements and reducing overall system complexity while maintaining full measurement capability.
Solution Approach 2:
The stationary beam splitter serves multiple functions: it directs the rotating laser beam toward the retina, reflects the returning light to the detector, and maintains a fixed optical path. This multi-functionality reduces the need for additional moving parts, thereby reducing device complexity.
4Adaptability or versatility
If mechanical scanning components are used, then measurement function is achieved, but device lifespan is reduced
Solution Approach 1:
The patent extracts the high-stress mechanical rotation from the mirror mounting system, which is typically a failure point. By making the mirror stationary and rotating only the laser source instead, the system eliminates wear and fatigue issues in the mirror mounting, thereby extending device lifespan.
Solution Approach 2:
The patent replaces the mechanically complex rotating mirror system with a system that rotates a lighter laser source while keeping the optical path elements stationary. This substitution reduces mechanical stress and wear on critical optical components, improving reliability and extending the device's operational life.
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
This approach reduces vibrations, lowers costs, extends device lifespan, minimizes noise, and allows for more efficient and accurate fixation and refraction error measurements with improved signal-to-noise ratio and reduced manufacturing complexity.
Implementation Method 1
a polarizing beam splitter configured to polarize light projected onto the one or more eyes as part of the target image and configured to polarize light reflected from the one or more eyes as part of the reflected image
Implementation Method 2
a first convex lens configured to receive the target image and a second convex lens configured to receive the reflected image from the one or more eyes
Implementation Method 3
a first convex lens configured to receive the target image and a second convex lens configured to receive the reflected image from the one or more eyes
Data Source
AI summary
A method and apparatus for fixation measurement includes projecting, by a projection apparatus, a target image onto one or more eyes of a patient and capturing, by one or more image sensing devices disposed conjugate to the one or more eyes, a reflected image reflected from the one or more eyes in response to the target image, wherein the reflected image includes information indicating the fixation of the one or more eyes.