Point-to-Point Focusing for High-Resolution Optical Scanning
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Solution Overview
Problem
Existing opto-electronic scanning devices suffer from low lateral spatial resolution due to a large laser spot size on diffusely scattering surfaces, which limits the ability to accurately measure detailed object features.
Innovation Solution
Incorporation of a high-speed autofocus optical module with a variable focal length lens or reconfigurable optical phase plate that allows real-time focus adaption of the measurement beam for each object point, enabling point-to-point focusing and continuous focus adjustment throughout the scanning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a laser beam is swept continuously over the object surface, then measurement speed is improved, but lateral spatial resolution deteriorates due to large laser spot size
Solution Approach 1:
The patent applies dynamics by making the focal length of the optical module variable rather than fixed. The optical module dynamically adjusts its focal length in real-time during the scanning process, allowing the laser beam to be focused at different depths corresponding to the continuously moving scan head position. This dynamic adjustment maintains a small laser spot size on the measurement surface even during continuous high-speed scanning, thereby resolving the contradiction between measurement speed and lateral spatial resolution.
2Length of stationary object
If the laser beam diameter is increased to improve measurement range, then measurement range is improved, but lateral spatial resolution deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the focal length parameter of the optical module based on the distance to the measurement surface. When the scan head is at different positions (different distances from the measurement surface), the optical module changes its focal length to maintain optimal beam focus. This allows the system to achieve both long measurement range and high lateral spatial resolution by adapting the beam parameters to the specific measurement conditions rather than using a fixed beam diameter.
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
Enhances spatial resolution by maintaining a small beam diameter and focus on each object point, improving the ability to capture detailed surface features with high precision and speed, even in varying distances and object geometries.
Implementation Method 1
a high-speed autofocus optical module, situated in the emitting beam path, designed for a real-time measurement focus adaption within a single object point measurement period and comprising a variable focal length lens or a reconfigurable optical phase plate
Implementation Method 2
a light source, preferably a so-called diffraction limited point light, pulsed and/or single-mode light source, for generation of a measurement beam
Implementation Method 3
a light source, preferably a so-called diffraction limited point light, pulsed and/or single-mode light source, for generation of a measurement beam
Data Source
AI summary
Method and opto-electronic measuring device for measuring of an object's surface with a measuring rate of at least one thousand object points per second. Using a high-speed autofocus optical module comprising at least one variable focal length lens or reconfigurable optical phase plate having a response time of under 1 ms, situated in an emitting beam path, there is a real-time focus adaption of the measurement beam within a single object point measurement period.