Laser Writer Micro-Sweeps for Non-Constant Exposure Velocity
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Solution Overview
Problem
Conventional laser writers write patterns only during constant motion of the printing head, limiting printing efficiency and accuracy, especially when nano-scale patterns are required.
Innovation Solution
Implementing a method that allows writing during acceleration and deceleration phases of the printing head by controlling a laser writer with a modulating optic and sweep deflection optic to vary laser beam intensity and deflection angle based on a non-constant velocity profile, using position-triggered micro-sweeps to maintain pattern precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the printing head moves at constant velocity only, then writing accuracy is maintained, but printing efficiency is limited
Solution Approach 1:
The system transitions from static constant-velocity writing to dynamic writing that adapts to changing velocities during acceleration and deceleration phases. The control system dynamically adjusts the modulation signal timing and parameters based on the actual printing head velocity, enabling accurate pattern writing throughout the entire motion cycle including non-constant velocity periods.
Solution Approach 2:
The system implements feedback control by monitoring the actual printing head velocity and using this information to adjust the modulation signal characteristics. The controller receives velocity information and dynamically modifies the writing parameters to compensate for velocity variations, ensuring pattern accuracy is maintained even during acceleration and deceleration.
2Productivity
If writing is performed during acceleration and deceleration, then printing efficiency increases, but pattern precision may deteriorate
Solution Approach 1:
The system changes the parameters of the modulation signal based on the printing head velocity. During acceleration and deceleration, the control system adjusts parameters such as modulation frequency, duty cycle, or pulse width to compensate for velocity-induced distortions. This dynamic parameter adjustment ensures that the deposited pattern maintains its intended geometry and precision regardless of velocity variations.
3Device complexity
If the modulation signal timing is not adjusted for velocity changes, then system complexity is reduced, but exposure dose uniformity deteriorates
Solution Approach 1:
The system performs preliminary velocity measurement and prediction before the actual writing process. The control system anticipates velocity changes based on motion commands and pre-adjusts the modulation signal timing and parameters accordingly. This proactive approach allows the system to compensate for velocity-induced dose variations without requiring complex real-time feedback mechanisms during the writing process itself.
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 printing efficiency by allowing writing during non-constant motion without compromising accuracy, particularly for nano-scale patterns, by ensuring uniform dose delivery and straight micro-sweeps.
Implementation Method 1
a modulating optic such as an acousto-optical modulator (AOM) which may modulate the intensity of each of the one or more laser beams according to the desired pattern
Implementation Method 2
a deflecting optic such as an acousto-optical deflector (AOD), which may modify one or more laser beams which are directed to a printing head that is scanned across the printing substrate
Data Source
Figure 1A~1D
Figure 1E~2
Figure 3~4
AI summary
There is disclosed herein a method for controlling a laser writer (100) and a laser writer (100) configured to perform such a method. The laser writer (100) comprises a printing head (102), a modulating optic (108), and a sweep deflection optic (110). The printing head (102) scans in a scanning direction (X) relative to a printing substrate (104), with a predetermined non-constant velocity profile. The sweep deflection optic (110) is controlled to carry out a micro-sweep based on a monitored position of the printing head (102) along the scan direction (X).