Ophthalmic Lens Optical Verification via Deformed Pattern Imaging
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Solution Overview
Problem
Current methods for verifying the optical characteristics of ophthalmic lenses are either expensive, complex, or fail to ensure the conformity of optical designs, with existing devices being sensitive to lens centering and requiring multiple patterns for measurement.
Innovation Solution
A method and device using a deformed and undistorted pattern, where the deformed pattern is constructed based on an intermediate pattern determined by optical ray tracing, allowing for global or local verification of optical characteristics, including the optical design, without the need for multiple original patterns, and utilizing image acquisition and processing to compare with reference patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a manual focimeter is used to measure the power of an ophthalmic lens, then the measurement can be performed locally over a limited area, but the device is very sensitive to the centering of the lens and requires manual operation which reduces productivity
Solution Approach 1:
The patent combines multiple measurement functions into a single automated device. The verification device integrates the ability to capture images of patterns through the lens, process these images to extract optical characteristics, and verify conformity all in one system, eliminating the need for separate manual measurement steps and improving productivity while maintaining measurement precision.
Solution Approach 2:
The patent replaces manual mechanical operation with automated image processing. Instead of manual focusing and reading of optical parameters, the system uses automated image capture, digital processing, and algorithmic extraction of optical characteristics, thereby increasing productivity and reducing operator dependency.
2Area of stationary object
If electronic focimeters of the type 'fronto-mappers' are used to perform global mapping of optical powers, then the measurement covers the entire lens surface, but the devices are generally expensive and difficult to implement
Solution Approach 1:
The patent uses a simplified optical verification method that captures an image of a pattern through the lens and processes it computationally. This approach creates a functional copy of the complex fronto-mapper capability using more accessible components: a simple imaging device, a test pattern, and image processing algorithms, thereby reducing equipment complexity while maintaining global measurement coverage.
Solution Approach 2:
The patent introduces a test pattern as an intermediary element between the lens and the imaging device. This pattern serves as a reference that, when imaged through the lens, encodes optical characteristic information that can be extracted through image processing, enabling global optical verification without requiring complex measurement equipment.
3Reliability
If identification means such as anti-counterfeiting labels are used to verify optical design conformity, then traceability is provided, but these means are easily falsifiable and do not guarantee a satisfactory level of security
Solution Approach 1:
The patent uses optical characteristics encoded in the lens itself (through the deformation of the test pattern image) as a security feature. These optical properties are inherent to the lens manufacturing process and are difficult to replicate, providing reliable verification of optical design conformity without relying on easily falsifiable labels or tags.
Solution Approach 2:
The patent makes the lens itself carry its own verification information through its optical properties. The lens inherently encodes its optical characteristics in the way it deforms the test pattern image, allowing self-verification without requiring external authentication systems or additional security components.
4Measurement precision
If two distinct grids are used in the Moiré measurement method to measure optical parameters, then the optical power map can be calculated, but the implementation becomes complex requiring multiple patterns and calibration steps
Solution Approach 1:
The patent extracts the essential measurement function from the complex Moiré method. Instead of using two grids and relying on Moiré interference patterns, the system uses a single test pattern and directly processes the imaged pattern to extract optical characteristics, simplifying the measurement system while maintaining the ability to map optical parameters across the lens surface.
Solution Approach 2:
The patent segments the verification process into distinct computational steps: image capture, pattern recognition, optical characteristic extraction, and conformity verification. This segmentation allows each step to be optimized independently and simplifies the overall system architecture compared to the integrated complexity of dual-grid Moiré systems.
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
Enables rapid, cost-effective verification of ophthalmic lens optical characteristics, ensuring compliance with expected designs and detecting illicit reproductions, while minimizing handling errors and equipment complexity.
Implementation Method 1
a) determining, under determined optical conditions, an image pattern which is the image of said deformed pattern through the verified ophthalmic lens
Data Source
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AI summary
The present invention concerns a method for checking the compliance of a checked optical characteristic of a checked ophthalmic lens (30) relative to an expected optical characteristic, from a non-deformed pattern (40) and a deformed pattern (20) each having a non-uniform contrast, the method comprising the steps of: a) determining (A) an image pattern (50), which is the image of the deformed pattern through the checked ophthalmic lens, in predefined optical conditions, b) combining (B) the image pattern with the non-deformed pattern to form a test pattern (60), c) comparing (C) the test pattern with at least one reference pattern (70), and d) deducing (D) the compliance of the checked optical characteristic with the expected optical characteristic on the basis of the preceding comparison. The invention also relates to a device for implementing such a checking method.