Optical Wavefront Sensor with Gradient Density Filter for High Resolution
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Solution Overview
Problem
Existing wavefront sensors for adaptive optics systems, such as those used in astronomy and ophthalmology, are complex and not well-suited for observing extended objects or point laser sources, and current interferometers require larger systems with lower accuracy and resolution.
Innovation Solution
A compact optical wavefront sensor system comprising a density gradient filter, a matrix of identical lenses, and a photodetector matrix, along with image processing to calculate partial derivatives of the wave surface, using a simplified filter transmission equation to enhance measurement accuracy and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interferometers are used for optical surface quality control, then measurement accuracy is improved, but system size and complexity increase
Solution Approach 1:
The patent segments the wavefront sensing function into multiple sub-functions performed by different components: a density gradient filter segments the wavefront into multiple beams, a lens matrix further segments these beams, and a photodetector matrix detects them. This segmentation allows the system to achieve interferometer-level accuracy without requiring a single large complex interferometer setup.
Solution Approach 2:
The patent introduces a density gradient filter as an intermediary element between the wavefront and the detection system. This filter modulates the wavefront information into spatially distributed beam intensities, serving as a mediator that converts complex wavefront measurements into simpler intensity measurements that can be performed with compact components.
2Adaptability or versatility
If adaptive optics systems use point laser sources, then wavefront sensing is enabled, but operational problems arise for extended objects
Solution Approach 1:
The patent creates a universal wavefront sensing system that can handle both point sources and extended objects through the same optical path. The density gradient filter and lens matrix configuration enables the system to extract wavefront information from any light source type without requiring different sensor configurations, achieving multi-functionality in a single device.
3Device complexity
If wavefront sensors are made more compact, then system size is reduced, but measurement resolution decreases
Solution Approach 1:
The patent transitions from one-dimensional wavefront encoding to two-dimensional spatial distribution of beam intensities. The density gradient filter creates a 2D pattern of beams across the photodetector matrix, allowing wavefront information to be encoded in both horizontal and vertical dimensions simultaneously. This dimensional expansion enables compact packaging while maintaining high measurement resolution through the rich 2D information content.
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
Achieves high-accuracy wavefront measurements with improved resolution and reduced complexity, suitable for both lens and afocal systems, overcoming environmental disturbances in less than a hundredth of a second.
Implementation Method 1
a density gradient filter, in a plane referenced (x', y') perpendicular to the optical axis of the optical measuring head, the transmission T(x', y') of said filter being governed by the equation: T(x', y') = 0.5 * (1 + sin(2πx'/px) + sin(2πy'/py))
Implementation Method 2
a matrix of photodetectors, each of the four lenses forming an image of the pupil in the plane of this matrix
Implementation Method 3
a matrix of photodetectors, each of the four lenses forming an image of the pupil in the plane of this matrix
Data Source
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AI summary
The technical field of the invention is that of systems for inspecting a surface of an optical wave output from an optical device (1), said optical device comprising an exit pupil (3), said inspection system comprising an optical measurement head (10) and a computer (20) for processing the images output from said optical measurement head. The optical measurement head comprises: a gradient density filter (11), the density varying periodically in two spatial directions, a matrix array comprising at least four identical square lenses 10 having the same focal length and arranged symmetrically, and a matrix array (13) of photodetectors, each of the four lenses forming, from the pupil, an image in the plane of the latter matrix array. The image-processing computer comprises computing means for computing the partial derivatives d Δ/dx (x, y) - d Δ/dy (x, y) of the wave surface ∆(x, y) in the plane of the exit pupil.