In-line Ophthalmic Inspection with Auto-Alignment Interferometer
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Solution Overview
Problem
Current interferometer systems for measuring ophthalmic devices are limited by alignment errors, tolerance stack-up, and lack of real-time feedback, making them inadequate for continuous or semi-continuous manufacturing processes, especially in noisy environments.
Innovation Solution
An in-line system featuring a vibration-resistant interferometer and automatic alignment system, including a camera and positioner, communicates with a central processing unit to determine the physical dimensions of ophthalmic devices in real-time, allowing for precise positioning and continuous quality control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a second beam splitter is added to the interferometer system to enable image projection for alignment, then alignment capability is improved, but measurement precision deteriorates due to error introduction and signal loss
Solution Approach 1:
The patent removes the second beam splitter from the interferometer system, extracting the problematic component that caused measurement errors and signal loss. Instead, it uses a vision system with a camera to capture and process alignment information directly from the interferometer's projected image, eliminating the need for the second beam splitter while maintaining alignment capability.
Solution Approach 2:
The patent introduces a vision system as an intermediary between the interferometer and the alignment process. The camera captures the projected image, and image processing algorithms extract alignment information, serving as a mediator that enables alignment without requiring the problematic second beam splitter.
2Ease of operation
If multiple components (second beam splitter, projection screen, camera) are used for alignment, then alignment functionality is improved, but device complexity increases due to tolerance stack-up
Solution Approach 1:
The patent removes the projection screen and second beam splitter from the system, extracting the components that contributed to device complexity and tolerance stack-up. The alignment functionality is maintained through direct imaging and digital processing of the interferometer's output.
Solution Approach 2:
The patent merges the alignment and measurement functions into a more integrated system. The vision system and interferometer work together as a unified measurement platform, reducing the number of separate components and their associated interfaces that contribute to complexity.
3Measurement precision
If conventional interferometer systems are used for off-line analysis, then measurement precision is maintained, but productivity decreases due to lack of real-time feedback
Solution Approach 1:
The patent implements preliminary alignment using the vision system to automatically position and center the interferometer on the lens before measurement begins. This preliminary action eliminates the need for manual alignment adjustments during the measurement process, enabling continuous real-time measurements without interrupting the manufacturing flow.
Solution Approach 2:
The patent implements automatic feedback control where the vision system continuously monitors the interferometer's alignment status and provides real-time adjustments. This feedback mechanism maintains measurement precision while enabling continuous operation, as the system automatically corrects any drift or misalignment without requiring manual intervention.
4Measurement precision
If manual alignment adjustments are made during measurement, then measurement precision can be maintained, but loss of time increases due to interruptions in continuous manufacturing
Solution Approach 1:
The patent implements self-aligning capabilities where the interferometer system automatically maintains its own alignment through integrated vision guidance and feedback control. The system serves itself by continuously monitoring and adjusting its own position, eliminating the need for external manual intervention that would interrupt the manufacturing process.
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 solution enables immediate feedback and automatic corrections during manufacturing, reducing off-specification materials and improving product quality by providing precise, real-time measurements of ophthalmic devices despite environmental vibrations and turbulence.
Implementation Method 1
an interferometer that is configured to project a measurement beam having a wavelength that transmits through a beam splitter onto the ophthalmic device
Implementation Method 2
a camera that is configured to image an actual position of a feature of the ophthalmic device
Data Source
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AI summary
Disclosed are in-line apparatuses, systems and methods for measuring a physical characteristic of a constant supply of an ophthalmic device, the apparatuses including: an interferometer; an automatic alignment system that positions the interferometer or ophthalmic device; and a central processing unit in communication with the automatic alignment system and receiving measurements from the interferometer. The in-line apparatus measures the desired physical dimensions of the ophthalmic device in real time. In-line systems, apparatuses and methods for measuring a physical characteristic of an ophthalmic device can include: a camera imaging an actual position of a feature of the ophthalmic device; a vibration resistant interferometer projecting a surface measurement beam having a wavelength that transmits through a beam splitter onto the ophthalmic device; and an automatic alignment system positioning the interferometer and the camera.