Laser Focal Position Control With Incident Shift Correction
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Solution Overview
Problem
In optical processing devices, accurately aligning the focal position of laser light with a surface of an object having a concave and convex or curved shape is challenging, leading to reduced accuracy in laser processing.
Innovation Solution
An optical device with a translation optical system that includes a rotatable mirror member with high reflectance surfaces, allowing for precise control of the optical path and focal position adjustment using a galvano motor and control unit, combined with a confocal optical system for real-time autofocus and correction of incident position shifts due to changing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional optical scanning device is used with fixed focal position, then the device structure is simple, but the processing accuracy deteriorates when processing objects with concave and convex or curved surfaces
Solution Approach 1:
The patent introduces a translation optical system with rotatable reflecting members that can dynamically adjust the optical path and focal position in real-time. This dynamic adjustment capability allows the system to adapt to varying object surface geometries (concave, convex, curved), maintaining accurate focal alignment throughout the processing area without requiring multiple fixed optical systems.
Solution Approach 2:
The patent adds a new dimension of control by introducing translation (parallel shifting) of light in addition to the conventional deflection (angular scanning). The translation optical system shifts the light path in the optical axis direction, enabling independent control of focal position while maintaining scanning capability, thus resolving the contradiction between fixed focal position and variable surface geometry.
2Manufacturing precision
If the focal position is adjusted for different surface positions, then the processing accuracy improves, but the incident position of light shifts due to changing angles
Solution Approach 1:
The patent implements a feedback control mechanism where the control unit monitors the focal position adjustment made by the translation optical system and automatically calculates compensatory adjustments. When the focal position is changed to match different surface positions, the system detects the resulting incident position shift and applies corrective translation to restore the light to the correct incident position, creating a closed-loop control system.
Solution Approach 2:
The patent performs preliminary calculation and compensation for incident position shifts. Before executing the focal position adjustment, the control unit pre-calculates the expected incident position deviation based on the translation amount and scanning angle, and applies the necessary compensatory translation in advance to prevent the shift from affecting processing accuracy.
3Adaptability or versatility
If a translation optical system with rotatable reflecting members is introduced, then the focal position can be adjusted for different surfaces, but the device complexity increases
Solution Approach 1:
The translation optical system uses rotatable reflecting members that perform multiple functions: they provide both angular deflection (scanning) and translation (focal position adjustment) capabilities within a single component. This multi-functionality allows the system to handle various surface geometries (concave, convex, curved, flat) with a unified optical structure, avoiding the need for separate optical systems for each surface type.
Solution Approach 2:
The patent introduces a control unit as an intermediary that manages the complexity of coordinating multiple optical components. The control unit receives processing position information, calculates the required translation and deflection amounts, and coordinates the rotatable reflecting members to achieve the desired optical path adjustment, thereby simplifying the overall system control while enabling complex optical maneuvers.
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 enhances the accuracy of laser processing by maintaining consistent focal alignment, even with complex object surfaces, thereby improving processing precision and reducing errors.
Implementation Method 1
a rotatable reflecting member (2) having a first reflecting surface (2a) and a second reflecting surface (2b)
Implementation Method 2
a condensing optical system which changes a focal position (z) of light to condense the light above a subject
Data Source
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AI summary
In an optical device capable of adjusting a focal position of laser light, the accuracy of laser processing is improved. An optical device which processes a subject by irradiating the subject with laser light, includes: a focal position adjustment mechanism configured to adjust a focal position of the laser light; an incident position adjustment mechanism configured to adjust an incident position of the laser light incident on the subject in a direction perpendicular to a focal direction of the laser light; and a control unit configured to control driving of the focal position adjustment mechanism and the incident position adjustment mechanism, wherein the control unit controls the driving of the incident position adjustment mechanism based on an amount of driving of the focal position adjustment mechanism to correct a shift of the incident position due to change of the focal position.