Coaxial Laser Distance Sensing for Scanned Workpiece Measurement
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Solution Overview
Problem
Conventional laser processing apparatuses face challenges in accurately measuring the distance to a workpiece due to the separation of distance measuring sensors from the optical axis, leading to reduced measurement accuracy and limited flexibility in changing measurement positions without moving the workpiece.
Innovation Solution
A laser processing apparatus with a distance measurement light emitting section and receiving elements arranged coaxially within the housing, utilizing a merging mechanism to guide distance measurement light and laser light, allowing for precise distance measurement and scanning, and incorporating a light receiving lens for accurate spot formation on the receiving elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the distance measuring sensor is arranged at a position deviating from the optical axis of the laser light, then the sensor can be separated from the objective condensing lens, but the measurement position on the workpiece cannot be changed without moving the workpiece
Solution Approach 1:
The patent introduces a scanning mechanism that enables the distance measurement light to be scanned across different positions on the workpiece surface. This dynamic scanning capability allows the measurement position to be changed without physically moving the sensor or workpiece, resolving the contradiction between sensor separation and measurement position flexibility.
2Adaptability or versatility
If the distance measurement light is made coaxial with the laser light optical axis, then the measurement position can be scanned, but the distance from the merging portion to the workpiece increases
Solution Approach 1:
The patent embeds the distance measurement optical system within the existing laser processing optical path. The distance measurement light is merged into the laser light optical path at a strategic point, allowing the measurement light to share portions of the optical path with the laser light. This nesting approach enables scanning capability while minimizing the increase in overall optical path length.
3Adaptability or versatility
If the optical path length is increased to enable scanning, then measurement position flexibility improves, but the reflected light may not form an appropriate spot on the light receiving element
Solution Approach 1:
The patent introduces a light receiving lens as an intermediary optical element that collects the reflected distance measurement light and focuses it onto the light receiving element. This intermediary lens ensures that even when the optical path length varies during scanning, the reflected light consistently forms an appropriate spot on the light receiving element, maintaining measurement precision across different measurement positions.
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 configuration enables high-accuracy distance measurement to the workpiece, with the ability to scan the measurement position and maintain accuracy even when one receiving element fails to receive the light, and increases measurement resolution by extending the optical path length.
Implementation Method 1
a distance measuring section which measures a distance from the laser processing apparatus to a surface of the workpiece by a triangulation method based on a light receiving position of the distance measurement light in the pair of light receiving elements
Implementation Method 2
a light receiving lens which is arranged inside the housing such that an optical axis of each of the pair of light receiving elements passes through the light receiving lens, and is arranged in the middle of an optical path connecting the merging mechanism and the pair of light receiving elements, and condenses the distance measurement light that has been reflected by the workpiece and has passed through the merging mechanism on respective light receiving surfaces of the pair of light receiving elements
Implementation Method 3
a merging mechanism which is provided in the middle of an optical path from the laser light output section to the laser light scanning section in the housing, guides the distance measurement light emitted from the distance measurement light emitting section to the workpiece via the laser light scanning section by merging the distance measurement light into the optical path
Data Source
AI summary
A laser processing apparatus includes a laser light output section, a laser light scanning section, a distance measurement light emitting section which emits distance measurement light, a pair of light receiving elements which receives the distance measurement light emitted from the distance measurement light emitting section and reflected by the workpiece, optical axes of the pair of light receiving elements being arranged inside the housing so as to sandwich an optical axis of the distance measurement light emitting section, a distance measuring section which measures a distance to the surface of the workpiece, and a light receiving lens which is arranged such that each of the optical axes of the pair of light receiving elements passes through the light receiving lens, and condenses the distance measurement light that has been reflected by the workpiece on respective light receiving surfaces of the pair of light receiving elements.