Lens Evaluation Device Aberration Measurement via Point Light Source Array
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Solution Overview
Problem
Conventional lens evaluation devices face challenges in accurately measuring lateral magnification, distortion aberration, field curvature, and chromatic aberration, particularly in optical systems like laser confocal microscopes, due to limitations in measurement precision and the need for highly accurate length meters, which increases measurement time and is prone to errors from optical system instability.
Innovation Solution
A lens evaluation device employing a plurality of point light sources arrayed on a flat surface, an imaging unit, a movement unit, and an image position calculation unit to capture stack images across multiple wavelengths, allowing for the calculation of image positions and fitting of aberration models to determine aberration measurement values, thereby correcting distortion and color deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single pin-hole is moved to multiple positions to measure the entire image surface, then measurement coverage is improved, but measurement time increases and optical system stability becomes problematic
Solution Approach 1:
The image surface is divided into multiple regions, with each pin-hole position responsible for measuring a specific region. This segmentation allows simultaneous measurement across the entire field of view, eliminating the need to sequentially move a single pin-hole across all positions, thus reducing measurement time while maintaining comprehensive coverage
Solution Approach 2:
The measurement approach transitions from one-dimensional sequential scanning (moving one pin-hole across positions) to two-dimensional parallel measurement (multiple pin-holes at multiple positions simultaneously). This dimensional change enables all measurement points to be captured in a single measurement cycle, resolving the time-coverage tradeoff
2Measurement precision
If highly accurate length meters are used to monitor pin-hole positions, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The mechanical measurement system (length meters physically monitoring pin-hole positions) is replaced with an optical computation system. The imaging device captures images of pin-holes at known array positions, and software algorithms calculate precise positions and aberrations from these images, eliminating the need for complex mechanical measurement instruments while maintaining high precision
Solution Approach 2:
Instead of directly measuring physical positions with length meters, the system creates optical copies (images) of pin-holes and performs measurements on these copies. The imaging device captures light patterns from pin-holes, and computational algorithms extract position information from these optical copies, simplifying the measurement system while preserving accuracy
3Measurement precision
If the image is enlarged by an enlargement optical system before imaging, then image position detection accuracy is improved, but device complexity and potential sources of error increase
Solution Approach 1:
The imaging device itself is designed with sufficient resolution to directly capture pin-hole images at their actual sizes without requiring external enlargement optics. The high-resolution sensor can resolve fine details of pin-hole images, enabling accurate position detection through computational analysis of the captured images, thereby eliminating the need for additional enlargement optical 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
This approach enables high-accuracy evaluation of optical system performance by reducing the need for precise length meters, shortening measurement time, and minimizing errors, while allowing for simultaneous image correction across the optical device.
Implementation Method 1
a pin-hole 51, which becomes a point light source, is installed on the object surface of an optical system 52 to be evaluated and is illuminated from behind by an illumination means
Data Source
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AI summary
This lens evaluation device comprises a plurality of point light sources (1, 4) arranged on the plane, an imaging unit (10) for picking up an object and obtaining its image, a movement unit (12) for changing the relative distance between the point light source or the imaging unit and the optical system (7, 9) to be evaluated, a storage medium (17) for recording stack images obtained by the imaging unit picking up the images of the plurality of point light sources via the optical system every time the movement unit changes the relative distance, an image position calculation unit (14) for calculating a plurality of image positions from the plurality of pieces of point light source image in the stack image recorded on the storage medium and an aberration acquisition unit (14) for fitting an aberration model function to the plurality of image positions calculated and obtaining an aberration measurement value.