Reflective 3D Lens With Varying Cylindrical Curvature For Astigmatism Correction
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Solution Overview
Problem
Standard astigmatism correction methods for lenses are inadequate for wide-angle optics, as they apply uniform cylindrical curvature, failing to account for varying astigmatism effects across the lens surface due to off-center object and viewer positions, leading to oblique angles and different optical effects at each location.
Innovation Solution
The design involves creating astigmatism-corrected free-space lenses with inside reflective 3D surfaces defined by multiple reflective optical elements, each with its own non-overlapping optical center axis, where the cylindrical curvature varies across the surface to counteract oblique astigmatism, using an array of 'oxels' that are small optical systems, allowing for individual astigmatism corrections based on the angle and location of light-emitting pixels relative to the user's eye.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If uniform cylindrical curvature is applied to the entire lens area for astigmatism correction, then the astigmatism is corrected at the center, but the astigmatism correction becomes inaccurate at off-center locations due to varying angles of incidence
Solution Approach 1:
The lens surface is divided into multiple zones or segments, each with its own cylindrical curvature parameters. The lens is segmented into a central zone and peripheral zones, where each zone has optimized astigmatism correction values tailored to its specific location and angle of incidence, allowing accurate correction across the entire wide field of view
Solution Approach 2:
Different regions of the lens are assigned different optical properties, specifically varying cylindrical curvature values. The central region has one set of astigmatism correction parameters while peripheral regions have different parameters optimized for their respective angles of incidence, ensuring locally optimal correction throughout the lens area
2Area of moving object
If the lens is designed for wide-angle optics with off-center object and viewer positions, then the field of view is expanded, but astigmatism effects vary across the lens surface leading to focus errors
Solution Approach 1:
The lens incorporates dynamically varying optical parameters across its surface, with cylindrical curvature values that change as a function of radial distance from the center. This dynamic variation in optical power across the lens surface allows the lens to maintain focus accuracy for rays entering at different angles, enabling wide-angle performance without sacrificing focus reliability
Solution Approach 2:
The optical parameters of the lens, specifically the cylindrical curvature and astigmatism correction values, are changed as a function of position across the lens surface. By varying these parameters radially, the lens compensates for the changing angles of incidence encountered in wide-angle applications, maintaining consistent focus accuracy across the expanded field of view
3Ease of manufacture
If a single cylindrical curvature equation is used for the entire lens, then the manufacturing process is simplified, but the correction fails to account for location-specific astigmatism variations
Solution Approach 1:
The lens manufacturing process is segmented into multiple steps, including the fabrication of zones with different cylindrical curvatures. This segmentation allows each zone to be optimized for its specific function while maintaining overall lens integrity, achieving high correction precision through a systematic multi-zone fabrication approach
Solution Approach 2:
The lens design incorporates multiple functional zones within a single optical element, where each zone serves the dual purpose of maintaining structural continuity while providing location-specific astigmatism correction. This multi-functionality allows the lens to achieve high correction precision without requiring multiple separate optical components
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 approach effectively counteracts defocus effects of astigmatism across a wide field of view by varying optical properties across the reflective 3D surface, providing precise astigmatism correction without the need for trial-and-error adjustments, resulting in improved focus and reduced errors.
Implementation Method 1
inside reflective three-dimensional (3D) surfaces defined by a plurality of reflective optical elements
Data Source
AI summary
A lens includes a material spanning an area and providing an inside reflective three-dimensional (3D) surface. The reflective 3D surface is defined by a plurality of reflective optical elements including a first reflective optical element and at least a second reflective optical element that each include a sub-element set including a center sub-element (CS) and a plurality of neighboring sub-elements. The plurality of reflective optical elements each have their own non-overlapping optical center axis; and a cylindrically bent spherical surface. The cylindrically bent spherical surface is defined by the neighboring sub-elements in each reflective optical element being located at different 3D points so that the reflective optical elements relative to at least one neighboring reflective optical element provides different values of spherical curvature and different values of cylindrical axis orientation. Each of the plurality of reflective optical elements can provide a different optical power for correction of astigmatism.