Aspheric Lens Axis Alignment via Wobbling Detection
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Solution Overview
Problem
Existing methods for determining the position of the axis of symmetry of an aspheric lens surface relative to a reference axis are time-consuming and lack precision, often resulting in aberrations that are difficult to correct.
Innovation Solution
Measuring the position of the center of curvature of the spherical portion of the lens surface and detecting the wobbling movement during rotation allows for the accurate determination of the axis of symmetry, using autocollimators or distance sensors to assess changes in inclination and distance, enabling quick and precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the entire aspheric lens surface is scanned with a measuring probe to obtain a three-dimensional image, then the axis of symmetry can be determined, but the measurement process is time-consuming and cannot be carried out without contact
Solution Approach 1:
The patent extracts only the essential measurement information needed to determine the axis of symmetry by measuring two specific orthogonal profiles of the lens surface, rather than scanning the entire surface. This selective extraction of critical data points dramatically reduces measurement time while maintaining sufficient accuracy for axis determination.
Solution Approach 2:
Instead of performing a complete 360-degree scan of the entire lens surface, the method performs partial measurements of only two orthogonal profiles. This partial action approach provides enough information to determine the axis of symmetry without the time penalty of comprehensive surface scanning.
2Loss of time
If two orthogonal profiles of the lens surface are measured to determine the axis of symmetry, then the measurement is faster, but the method requires contact measurement
Solution Approach 1:
The patent replaces mechanical contact measurement probes with optical measurement systems (such as laser scanners or interferometers) that can capture lens surface profiles without physical contact. This substitution maintains the efficiency of measuring only two profiles while eliminating the drawbacks of contact measurement.
3Productivity
If the center of curvature of the spherical portion is determined and the lens is rotated to detect wobbling movement, then the axis of symmetry position can be determined quickly and accurately, but the device complexity increases
Solution Approach 1:
The patent utilizes the wobbling movement (vibration) of the lens during rotation as a measurable signal to determine the axis of symmetry position. By detecting the amplitude and phase of this natural wobbling motion, the system can quickly identify alignment errors without requiring complex active vibration excitation mechanisms.
Solution Approach 2:
The lens itself generates the measurement signal through its own wobbling movement during rotation. The measurement system simply needs to detect this naturally occurring motion rather than requiring complex external excitation devices, thereby reducing overall system complexity while maintaining high measurement speed.
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 method significantly reduces the time and effort required to determine the axis of symmetry with high accuracy, effectively correcting aberrations and ensuring proper alignment in optical systems.
Implementation Method 1
the position of the center of curvature of the spherical portion of the lens surface is measured with the aid of an autocollimator
Implementation Method 2
an autocollimator or a distance sensor is used in order to determine a wobbling movement which describes the lens surface during a rotation
Implementation Method 3
an autocollimator or a distance sensor is used in order to determine a wobbling movement which describes the lens surface during a rotation about an axis of rotation
Data Source
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AI summary
The method involves determining a position of a curvature center (21) of a spherical portion of an aspheric lens surface (16), and determining an inclination of a radial profile of the lens surface in an area of the surface lying in a measuring window. The surface is rotated around a rotation axis, so that another area of the surface reaches into the window. The inclination of the profile is determined in one of the areas of the surface. A position of a symmetric axis (20) of the surface relative to the rotation axis is determined from measured values by inclination determination. An independent claim is also included for a device for determining a position of a symmetric axis of an aspheric lens surface relative to a reference axis.