Laser Focus Control for Precise Modified Region Formation
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Solution Overview
Problem
The existing laser processing apparatuses face precision issues when moving the focusing position from outside to inside an object, leading to potential overshooting and a drop in precision in following the laser light incident surface displacement.
Innovation Solution
A laser processing apparatus and method that include a support portion, an emission portion, a moving mechanism, and a controller. The controller executes processes to move the focusing position along the object's peripheral edge and then inside, using measurement data to adjust the position of the support and condenser lens along the optical axis, ensuring precise alignment and preventing overshooting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the support portion or emission portion is moved so that the focusing position moves from outside the object to inside the object, then the modified region can be formed inside the object, but the control signal overshoots right after the focusing position moves into the object, causing a drop in precision in following the laser light incident surface displacement
Solution Approach 1:
The system performs preliminary action by acquiring measurement data on the laser light incident surface displacement before the focusing position moves into the object. This measurement data is then used to adjust the driving signal to the driving portion, pre-compensating for potential overshooting and ensuring precise following of the surface displacement throughout the entire process including when the focusing position transitions from outside to inside the object.
2Manufacturing precision
If the condenser lens is caused to follow the laser light incident surface displacement, then the processing precision is maintained, but the control signal may overshoot when the focusing position moves into the object, reducing the reliability of the following action
Solution Approach 1:
The system employs feedback by continuously measuring the actual displacement of the laser light incident surface using the measurement data acquiring portion. This measured displacement information is fed back to the controller, which then adjusts the driving signal to the driving portion in real-time. This closed-loop feedback mechanism ensures that the condenser lens accurately follows the surface displacement without overshooting, even when the focusing position transitions from outside to inside the object.
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 enhances precision in following the laser light incident surface displacement, preventing overshooting and maintaining accuracy during the formation of modified regions inside the object.
Implementation Method 1
a laser processing apparatus that emits a condensed laser light onto an object to forms a modified region on the object
Implementation Method 2
an emission portion that emits a laser light onto the object via a condenser lens
Data Source
AI summary
The controller executes a first process of moving a support portion so that inside the peripheral edge of an object, a focusing position moves along the peripheral edge, thereby forming a first modified region, and following the first process, executes a second process of moving the support portion so that the focusing position moves, thereby forming a second modified region The measurement data acquiring portion, at execution of the first process, acquires measurement data associated with position information on a position of the object. The controller, at execution of the second process, causes the driving portion to shift a position of the condenser lens, the position being along the direction of an optical axis, to an initial position based on the measurement data acquired in the first process, before or when the focusing position moves from outside of the object to inside thereof.