Lens Characterization Using Scanning Linear Flux and Hartmann Plate
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Solution Overview
Problem
Conventional lens characteristic evaluation devices face issues with degradation of measurement sensitivity at the center and peripheral portions of captured images due to brightness differences, and increased device size from moving screen mechanisms, which affect the accuracy of optical characteristic evaluation.
Innovation Solution
A lens characteristic evaluation device that uses a scanning optical system to scan the test lens with a linear luminous flux, a Hartmann plate with two-dimensionally arranged pinholes, and a photographing optical system to capture images without moving the screen, ensuring consistent brightness and preventing overlapping or inversion of point images, while utilizing position acquisition and determination units to accurately assess optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the distance from the test lens to the screen is made longer to improve sensitivity, then the sensitivity (resolution) of the lens characteristic evaluation device is improved, but two pieces of point images corresponding to different pinholes may be overlapped or their positional relationship may be inverted
Solution Approach 1:
The patent applies dynamics by making the screen movable relative to the test lens. The screen can be positioned at different distances from the test lens depending on the refractive power of the lens being measured. For strong plus power lenses, the screen is positioned closer to prevent image overlap and inversion, while for weak plus or minus power lenses, the screen is positioned farther away to maximize sensitivity. This dynamic adjustment resolves the contradiction between sensitivity and measurement accuracy.
2Measurement precision
If a moving mechanism is added to change the screen distance to prevent image overlap, then the accuracy of optical characteristic evaluation is maintained, but the device size becomes large
Solution Approach 1:
The patent replaces the complex mechanical moving mechanism with a simpler computational approach. Instead of physically moving the screen to different positions, the system captures images at a fixed screen position and uses image processing techniques to virtually reposition and analyze the point images. This substitution eliminates the need for large mechanical movement mechanisms while maintaining the ability to evaluate optical characteristics accurately.
3Adaptability or versatility
If the screen is moved to different positions to measure different lens types, then the versatility of the device is improved, but the device complexity increases
Solution Approach 1:
The patent replaces the mechanical screen movement system with a computational image processing system. The photographing optical system captures images at a fixed screen position, and then processing units analyze these images to determine optical characteristics for different lens types. This approach maintains versatility in measuring various lens types (strong plus, weak plus, minus power) without requiring complex mechanical movement mechanisms.
4Measurement precision
If the distance from the test lens to the screen is made longer to increase sensitivity, then the sensitivity is improved, but the device complexity increases due to the need for moving mechanisms
Solution Approach 1:
The patent replaces the mechanical screen movement system with a computational image processing system. The photographing optical system captures images at a fixed screen position, and then processing units analyze these images to determine optical characteristics for different lens types. This approach maintains versatility in measuring various lens types (strong plus, weak plus, minus power) without requiring complex mechanical movement mechanisms.
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 solution prevents sensitivity degradation and device size increase by maintaining consistent image brightness and accurately determining pinhole positions, enabling precise evaluation of optical characteristics regardless of lens type without the need for a moving screen mechanism.
Implementation Method 1
a scanning optical system configured to scan a surface of the test lens with a linear luminous flux
Implementation Method 2
a Hartmann plate provided on a side opposite to the scanning optical system with respect to the test lens and having a plurality of two-dimensionally arranged pinholes, the Hartmann plate being configured to transmit the linear luminous flux which has passed through the test lens and radiated on the pinholes
Implementation Method 3
a photographing optical system provided on a side opposite to the Hartmann plate with respect to the screen and configured to photograph the screen while the scanning with the linear luminous flux is being performed by the scanning optical system
Data Source
AI summary
A lens characteristic evaluation device includes: a scanning optical system configured to scan a surface of a test lens with a linear luminous flux; a Hartmann plate provided on a side opposite to the scanning optical system with respect to the test lens and having a plurality of two-dimensionally arranged pinholes, the Hartmann plate being configured to transmit the linear luminous flux which has passed through the test lens and radiated on the pinholes by the scanning performed by the scanning optical system; a screen on which the linear luminous flux having passed through the Hartmann plate is projected; and a photographing optical system provided on a side opposite to the Hartmann plate with respect to the screen and configured to photograph the screen while the scanning with the linear luminous flux is being performed by the scanning optical system.