Diffractive Lens Measurement via Diffraction Order Filtering
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Solution Overview
Problem
Current wavefront measurement systems are not designed to effectively evaluate the optical properties of multifocal diffractive intraocular lenses, which have multiple powers, making it difficult to measure their optical quality in both laboratory and clinical settings.
Innovation Solution
A method involving the filtration of diffraction orders to isolate and measure the optical properties of individual lens powers using a wavefront sensor, where light from one diffraction order is blocked, allowing for the analysis of the optical quality of a single lens power, and high-resolution local wavefront measurements within each diffraction zone to reconstruct the overall optical properties of the lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional wavefront measurement systems are used to measure multifocal diffractive lenses, then the measurement system remains simple and single-focus oriented, but the measurement precision and ability to evaluate multiple lens powers is insufficient
Solution Approach 1:
The patent segments the measurement process by filtering light from different diffraction orders separately. A diffraction order filter is used to isolate and measure each lens power (e.g., distance vision and near vision powers) independently, allowing the complex multifocal lens to be evaluated as multiple separate optical systems. This segmentation enables precise measurement of each focal point's optical properties without interference from other powers.
Solution Approach 2:
The patent introduces an intermediary component - the diffraction order filter - that mediates between the multifocal lens and the wavefront sensor. This filter selectively transmits light from specific diffraction orders while blocking others, enabling the measurement system to evaluate individual lens powers. The intermediary allows the simple single-focus wavefront sensor to measure complex multifocal lenses by filtering the incoming light before it reaches the sensor.
2Measurement precision
If light from multiple diffraction orders is measured simultaneously, then the measurement process is simple and fast, but the ability to analyze individual lens power quality is lost
Solution Approach 1:
The patent employs periodic action by sequentially measuring different diffraction orders rather than attempting to measure them all simultaneously. The system filters and measures one diffraction order at a time, then moves to the next order in a systematic sequence. This periodic measurement approach allows precise analysis of each lens power's optical quality while maintaining reasonable measurement efficiency through automated sequential processing.
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 accurate measurement of optical properties across the lens surface, generating image quality parameters like modulation transfer function, and identifying beneficial or detrimental regions for optical performance, thus improving the evaluation and manufacturing of multifocal diffractive lenses.
Implementation Method 1
Wavefront measurement systems are used in ophthalmology and other fields to measure an optical wavefront
Implementation Method 2
Periodic diffractive structures can diffract light simultaneously into several directions, also typically known as diffraction orders
Data Source
AI summary
A method and system for measuring an optical property of a multi-focal lens are disclosed. One embodiment of the method comprises: filtering out light transmitted by all but one of a plurality of diffraction orders of the lens to provide an unfiltered light from a single diffraction order; receiving the unfiltered light at a wavefront detector; and analyzing the unfiltered light at the wavefront detector to measure the optical property. The multi-focal lens can be a multi-focal diffractive intra-ocular lens. The measured optical property can be a discontinuity in the lens surface. Filtering can comprise blocking all but the unfiltered light using an aperture operable to let through the unfiltered light from the single diffraction order, and/or blocking all but the unfiltered light using an opaque obstruction operable to let through only a selected amount of light corresponding to the light transmitted by the single diffraction order. The method can further comprise generating an image quality parameter, such as a modulation transfer function, based on the measured optical property.