Fiber Optic Interferometer for Vibration-Resistant Lens Thickness Measurement
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Solution Overview
Problem
Current methods for measuring the thickness of ophthalmic lens molds are limited by their inability to accurately measure curved surfaces and are often impractical for use on manufacturing lines due to sensitivity to vibrations and noise, especially when using linear coordinates or traditional interferometers.
Innovation Solution
The use of fiber optic interferometry with a dual interferometer apparatus, including a non-coherent and coherent light source, to generate interference fringes for precise measurement of mold thickness, which is non-destructive and non-contact, allowing for accurate measurement of center thickness on manufacturing lines while being resistant to vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional interferometers are used for thickness measurement, then measurement precision can be achieved, but the system becomes sensitive to vibrations and manufacturing noise
Solution Approach 1:
The patent replaces traditional mechanical interferometer systems with a fiber optic-based interferometric measurement system. This substitution eliminates the mechanical components that are sensitive to vibrations while maintaining the interferometric principle for precise thickness measurement. The fiber optic probe contains the interferometric functionality within an integrated optical system that is inherently more resistant to environmental disturbances.
Solution Approach 2:
The patent modifies the measurement system by changing from conventional interferometer parameters to fiber optic-specific parameters, including using optical fibers as the transmission medium and implementing measurement logic optimized for fiber optic delivery. This parameter change allows the system to achieve vibration resistance while maintaining measurement precision through the use of fiber optic immunity to electromagnetic interference and mechanical stability.
2Ease of manufacture
If linear coordinates are used for measurement, then measurement simplicity is maintained, but curved surfaces cannot be measured accurately
Solution Approach 1:
The patent transitions from linear coordinate measurements to three-dimensional spatial measurements by implementing a scanning mechanism that moves the fiber optic probe across the mold surface in multiple dimensions. This allows the system to capture depth information at multiple points and reconstruct the complete three-dimensional geometry of curved mold surfaces, achieving accurate measurement of complex shapes while maintaining system simplicity through automated scanning and digital processing.
3Reliability
If non-contact measurement method is used, then the measurement process becomes non-destructive, but measurement of curved surfaces requires complex positioning
Solution Approach 1:
The patent implements self-positioning capabilities through automated scanning mechanisms and computer-controlled probe positioning systems. The system automatically navigates the fiber optic probe across the mold surface, eliminating the need for manual positioning while maintaining non-contact measurement. The automated system includes feedback control that adjusts probe position and orientation to optimize measurement of curved surfaces, reducing operational complexity despite increased device automation.
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 method provides accurate, non-destructive, and non-contact measurement of mold thickness, reducing manufacturing noise and ensuring precise center thickness measurements, even on curved surfaces, enhancing the efficiency and accuracy of ophthalmic lens mold production.
Implementation Method 1
obtaining measurements of the contact lens thickness as generated by interference fringes created by the interferometer
Implementation Method 2
An interferometer is a measurement instrument that utilizes optical interference to determine various characteristics of optical surfaces. Interferometers typically generate a precise monochromatic wavefront, such as that of a laser, and split it using a beam splitter.
Implementation Method 3
These wavefronts are passed through a sample and a reference optical system, respectively, to create interference fringes which may then be measured.
Data Source
AI summary
This invention relates to an apparatus for measuring a sample contact lens. In particular, the present invention has a housing to hold a sample contact lens to be measured, one or more movement stages connected to the housing, and an interferometer.