Refraction Measurement Device Using Beam Splitter
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Solution Overview
Problem
Current refraction measurement methods, especially those using the reverse Shack-Hartmann method, face challenges such as requiring multiple subjective alignment operations, having a limited field of view, and being unable to distinguish between inherent and accommodated refractive states of the eye.
Innovation Solution
The proposed solution involves a refraction measurement device that combines a measurement channel based on the reverse Shack-Hartmann principle with an imaging channel optically, using a beam splitter or other optical combiners, to allow for a single image through the measured system and improve accuracy and field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple subjective alignment operations are used in reverse Shack-Hartmann refraction measurement, then measurement can be performed, but measurement precision and ease of operation deteriorate due to complexity and subjectivity
Solution Approach 1:
The system performs self-alignment by capturing an image of the reticle through the optical system and automatically determining alignment based on the captured image, eliminating the need for manual subjective alignment operations while maintaining measurement precision
Solution Approach 2:
Manual mechanical alignment operations are replaced with an automated image processing system that uses captured reticle images to determine alignment, substituting subjective human judgment with objective computational analysis
2Measurement precision
If reverse Shack-Hartmann method is used, then refraction measurement can be performed, but field of view is limited
Solution Approach 1:
The measurement channel and imaging channel are merged into a single integrated optical path, allowing the system to simultaneously perform refraction measurements and capture images, thereby expanding the effective field of view while maintaining measurement precision
Solution Approach 2:
The optical system is designed to serve multiple functions through a single optical path, including both refraction measurement and imaging capabilities, making the system more versatile and expanding its operational field of view
3Measurement precision
If separate measurement and imaging channels are used, then refraction measurement can be performed, but device complexity increases
Solution Approach 1:
The measurement channel and imaging channel are combined into a single shared optical path using optical combiners, reducing the number of separate components and simplifying the overall device structure while maintaining both measurement and imaging functions
Solution Approach 2:
A single optical path is designed to perform multiple functions including refraction measurement and imaging, eliminating the need for separate dedicated channels and thereby reducing device complexity
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 combination enables more accurate and precise refraction measurements by accounting for subjective input and improving optical alignment, while also expanding the field of view and accommodating different pupillary distances.
Implementation Method 1
using a beam splitter or other optical combiners
Data Source
AI summary
In an embodiment, multiple conjugate planes are used to create a plurality of optical pupil planes and a plurality of image planes. These optical planes solve multiple problems and introduce significant performance enhancements in the system. In one implementation of a disclosed embodiment, the measurement channel is based on the reverse Shack-Hartmann principle. By introducing a relay system (for example a 4-f lens system) the slit plane could be made conjugate to the measured system pupil plane (unlike a previous implementation where the slits were places away from the pupil plane as it was not accessible directly). Creating a virtual pupil plane allows for more accurate placement of the plane without the need for contact with the measured optical system.