Concentric Spherical MTF Layout for Dense Optical Field Measurement
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Solution Overview
Problem
Existing MTF measurement devices for optical systems face limitations in achieving high measuring point density without increasing device size or incorporating movable parts, which affect accuracy and speed.
Innovation Solution
A device with a rigid holding structure comprising multiple concentric spherical shells supports MTF measuring devices at fixed positions, allowing simultaneous measurements at different angular positions without overlapping fields of view, enabling high measuring point density and compact dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of MTF measuring devices is increased to achieve high measuring point density, then measurement precision is improved, but device size becomes unmanageably large
Solution Approach 1:
The patent applies nesting by placing multiple MTF measuring devices on concentric spherical shells, where inner shells contain measuring devices for central field positions and outer shells contain devices for peripheral field positions. This nested spherical arrangement allows high measuring point density in the central region while maintaining compact overall device dimensions, as smaller-radius shells fit within the spatial envelope of larger-radius shells.
Solution Approach 2:
The patent transitions from a two-dimensional planar arrangement of measuring devices to a three-dimensional spherical shell configuration. By distributing measuring devices across multiple concentric spherical shells with different radii, the system achieves high measuring point density without increasing the device's footprint in any single dimension, effectively utilizing the third dimension (radial distance) to pack more measuring points.
2Measurement precision
If MTF measuring devices are arranged closely to increase measuring point density, then measurement precision is improved, but the devices begin to overlap their fields of view
Solution Approach 1:
The patent applies local quality by assigning different spherical shell radii to different angular ranges of the image field. Central field positions use measuring devices on inner spherical shells, while peripheral field positions use devices on outer spherical shells. This localized assignment ensures that each measuring device operates in its optimal angular range without field of view overlap, while collectively achieving high measuring point density across the entire field.
Solution Approach 2:
The patent uses spherical shell geometry to naturally prevent field of view overlap. By arranging measuring devices on the surface of concentric spheres and directing their optical axes toward the center of curvature, the curved spherical geometry ensures that fields of view diverge appropriately for devices at different angular positions, eliminating overlap while maintaining high spatial density of measuring points.
3Adaptability or versatility
If a movable structure is used to reposition measuring devices, then adaptability is improved, but measurement accuracy and speed deteriorate due to mechanical complexity
Solution Approach 1:
The patent segments the measuring device array into multiple fixed spherical shells, where each shell is optimized for specific angular ranges. This segmentation allows the system to achieve adaptability by selectively activating appropriate shells for different measurement scenarios, while maintaining the mechanical simplicity and high accuracy of fixed positions, avoiding the need for movable components.
Solution Approach 2:
Instead of using a movable structure to achieve adaptability, the patent inverts the approach by using multiple fixed structures at different positions. The adaptability is achieved through the pre-configured diversity of fixed spherical shells rather than through movement, thereby maintaining measurement accuracy and speed while providing flexible measurement capabilities.
Data Source
AI summary
A device for measuring imaging properties of an optical system including: a rigid holding device; and MTF measuring devices arranged at predefined positions of the holding device such that, by each of the MTF measuring devices, a modulation transfer function can be measured at respective different, predefinable, angular positions in the image field of the optical system; wherein the holding device includes at least a first holder and a second holder; the MTF measuring devices include a first group and a second group; the first holder holds the first group at first positions so that the first group are arranged on a first spherical shell; the second holder holds the second group at second positions so that the second group are arranged on a second spherical shell; and the first spherical shell and the second spherical shell have different radii and are arranged so as to be mutually concentric.