Laser Phase Control with Reference Light for Focus Correction
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Solution Overview
Problem
In existing laser processing devices, it is difficult to distinguish between changes in convergence position caused by the light source and other optical systems, making feedback control of phase controllers complex and inefficient.
Innovation Solution
The laser device employs a phase control unit that branches laser light into control and non-control light, using non-control light to detect changes in the convergence state, allowing for easy correction through feedback control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a semi-reflection mirror is used to guide all laser light to the convergence position measuring unit, then the convergence position can be measured, but it becomes difficult to detect whether the change in convergence position is caused by the light source or other optical systems
Solution Approach 1:
The patent segments the laser light into two separate paths: one for measurement (through the semi-reflection mirror to the convergence position measuring unit) and another for reference (through the object to the reference light receiving unit). This segmentation allows independent detection of convergence position changes and light source changes, resolving the contradiction by enabling precise measurement while simplifying control through clear distinction of change sources.
Solution Approach 2:
The patent introduces an intermediary reference light path that passes through the object and is detected by the reference light receiving unit. This intermediary serves as a mediator to distinguish between convergence position changes and light source changes, allowing the control unit to identify the source of convergence position changes without increasing overall system complexity.
2Manufacturing precision
If feedback control is performed on the phase controller to correct convergence position changes, then processing quality can be maintained, but the control becomes complex when the source of change cannot be identified
Solution Approach 1:
The patent implements feedback control by comparing the convergence position measured by the convergence position measuring unit with a target value, and adjusting the phase controller accordingly. The reference light receiving unit provides additional feedback about light source changes, enabling the control unit to distinguish between convergence position changes requiring phase controller adjustment and light source changes requiring light source adjustment, thereby maintaining processing quality while simplifying control logic.
Solution Approach 2:
The reference light receiving unit acts as an intermediary that provides information about light source stability. This intermediary enables the control unit to make informed decisions about whether to adjust the phase controller or the light source, reducing feedback control complexity while maintaining manufacturing precision.
3Ease of operation
If non-control light is used for detection, then changes in convergence state caused by the light source can be easily detected and corrected, but some laser light is not subjected to the desired phase control
Solution Approach 1:
The patent extracts a portion of the laser light to form a reference light path that passes through the object and is detected by the reference light receiving unit. This extracted reference light serves as a basis for detecting light source changes without interfering with the phase-controlled measurement light, enabling easy convergence state correction while minimizing energy loss by using only a portion of the total laser light.
Solution Approach 2:
The reference light path acts as an intermediary that provides detection capability without competing with the phase-controlled light for energy. This intermediary enables easy detection and correction of convergence state changes while accepting minimal energy loss, as the reference light path uses a small portion of the total laser light output.
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 approach enables precise maintenance of laser light convergence at a specific initial value, reducing machine differences when multiple devices are used in parallel and ensuring consistent processing quality.
Implementation Method 1
a portion of the laser light emitted from the laser light source is controlled in the spatial phase by the phase control unit to become the control light
Implementation Method 2
another portion of the laser light emitted from the laser light source converges toward the detection surface of the detector as the non-control light through the lens
Data Source
Figure 1
Figure 2
Figure 3(a)~3(c)
AI summary
Disclosed is a laser device including: a laser light source configured to emit laser light; a phase control unit configured to receive the laser light emitted from the laser light source, to control a spatial phase of a portion of the laser light, to emit the portion of the light as control light, and to emit another portion of the laser light as non-control light; a first optical system configured to irradiate an object with the control light emitted from the phase control unit; a detector configured to detect the non-control light emitted from the phase control unit; a second optical system configured to cause the non-control light emitted from the phase control unit to converge toward a detection surface of the detector; and a control unit configured to execute a correction process for controlling the phase control unit to correct a control state for a spatial phase of the control light in the phase control unit on the basis of a detection result for the non-control light from the detector.