Acousto-Optic Laser Deflection Power Uniformity Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laser working apparatuses face challenges in achieving uniform working when using acousto-optic deflection means, as the diffraction efficiency varies with deflection angle, leading to inconsistent laser beam output and reduced productivity in forming fine holes and grooves on semiconductor wafers.
Innovation Solution
A laser beam irradiation apparatus is designed with acousto-optic deflection means, including RF oscillators for adjusting deflection angles and output amplitudes, and a control system that uses beam splitters and light reception devices to detect actual output power and adjust the deflection angles to maintain uniformity across all irradiation positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If acousto-optic deflection means is used to deflect the laser beam, then the laser beam can be irradiated at different working positions, but the diffraction efficiency differs depending on the deflection angle, making the output of the laser beam different and preventing uniform working
Solution Approach 1:
The patent introduces feedback control by detecting the actual output power of the laser beam at each deflection angle using a photodetector, storing this information in memory, and using it to automatically adjust the RF amplitude to maintain constant output power across all deflection angles
Solution Approach 2:
The patent changes the RF amplitude parameter dynamically based on the deflection angle to compensate for variations in diffraction efficiency, thereby maintaining constant laser beam output power despite changes in deflection angle
2Manufacturing precision
If a pulse laser beam is irradiated on the same portion by a plural number of times to form a fine hole, then the fine hole can be formed, but the movement of the work must be performed by a plural number of times, reducing productivity
Solution Approach 1:
The patent enables continuous useful action by using acousto-optic deflection to continuously scan the laser beam across multiple positions during a single work movement, eliminating the need for repeated work movements and indexing operations
Solution Approach 2:
The patent introduces deflection angle as an additional dimension for laser beam positioning, allowing the laser to reach multiple work positions by changing deflection angles while the work moves continuously in a single dimension
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
The apparatus ensures uniform working by equalizing the actual output power of the laser beam across different deflection angles, enhancing productivity and consistency in forming fine holes and grooves on semiconductor wafers.
Implementation Method 1
an acousto-optic device configured to deflect the optical axis of the laser beam oscillated by the laser beam oscillation means
Implementation Method 2
a beam splitter disposed between the acousto-optic device and the condenser and configured to split part of the laser beam deflected by the acousto-optic device
Implementation Method 3
a light reception device configured to receive the laser beam split by the beam splitter, the laser beam output detection means sending a light reception signal received by the light reception device to the control means
Implementation Method 4
a condenser configured to condense the laser-beam deflected by the acousto-optic deflection means
Data Source
AI summary
A laser beam irradiation apparatus includes an oscillation unit, an acousto-optic deflection unit for deflecting a laser beam oscillated by the oscillation unit, a condenser for condensing the deflected laser beam, and a control unit. The control unit determines an actual output power of the laser beam based on a light reception signal received from laser beam output detection means in response to a control signal for controlling a deflection angle adjustment unit of the deflection unit. Then, the control unit arithmetically operates the ratio of an actual output power corresponding to the control signal with reference to the lowest value of the actual output power. Further, the control unit arithmetically operates a correction value corresponding to the ratio of the actual output power to produce a control map and controls the output adjustment unit based on the control map.