Acousto-Optical Beam Splitter Intensity Control
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Solution Overview
Problem
Existing devices using acoustic-optical elements for splitting and modulating laser beams face issues with varying beam energies due to frequency superposition, leading to periodic energy fluctuations and higher-order beat frequencies, which disrupt the writing or exposure process in laser printers and lithography systems, and require complex amplitude control.
Innovation Solution
A device with an acoustic-optical element operated by multiple electrical signals, a signal generator, intensity control circuit, phase modulation circuit, and trigger circuit to regulate beam intensities and phases independently, ensuring constant energy distribution and synchronized modulation, minimizing temporal energy fluctuations by coordinating processes via a trigger signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple electrical signals with different frequencies are applied to the acoustic-optical element to split the laser beam into multiple beams, then the productivity and speed of the laser system is improved, but the beam energies vary due to frequency superposition and beat effects
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the required signal amplitudes for each frequency in a lookup table before operation. The control unit retrieves these pre-computed values based on the desired number of beams, allowing immediate adjustment without complex real-time calculations. This prevents energy fluctuations by ensuring the correct amplitudes are applied from the start, resolving the contradiction between fast beam splitting and stable beam energy.
2Quantity of substance
If the number of frequencies applied to the acoustic-optical element is increased to generate more beams, then the quantity of beams is improved, but higher-order beat frequencies occur that generate additional diffracted beams and disrupt the writing process
Solution Approach 1:
The patent converts the harmful beat effects into a beneficial phenomenon by deliberately using frequency superposition to create intensity modulation patterns. The control unit calculates specific amplitude combinations that exploit constructive and destructive interference to generate the desired number of beams with controlled energies. By treating the beat effects as a controllable resource rather than a disturbance, the system can generate multiple beams while maintaining writing process integrity.
3Manufacturing precision
If complex amplitude control circuits are implemented to maintain constant beam energies, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The patent applies self-service by implementing an automatic control system that uses a lookup table and microprocessor to autonomously determine and apply the correct signal amplitudes. The control unit automatically retrieves pre-computed amplitude values based on the desired number of beams and adjusts the signal generators accordingly, eliminating the need for manual calibration or complex analog control circuits. This automated approach achieves high precision while keeping the hardware relatively simple.
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 device achieves stable, constant energy distribution among split beams, reducing the need for complex in-situ energy recording and allowing independent adjustment of beam distances and phases, enhancing the reliability and efficiency of the splitting and modulation process.
Implementation Method 1
an acoustic-optical element which is operated with a large number of electrical signals with different frequencies in order to split or to split up the beams emitted by the radiation source into a large number of beams
Implementation Method 2
a second acoustic-optical element, in particular an acoustic-optical modulator, by means of which the focused partial beams can be modulated separately from one another
Data Source
Figure 1
Figure 2
AI summary
A device for the optical splitting and modulation of monochromatic coherent electromagnetic radiation, in particular light beams and/or laser beams, contains a beam source (2), an acousto-optical element (8) disposed downstream of the latter and serving for splitting the beam (4) generated by means of the beam source into a number of partial beams (Ll, L2, L3, L4), a modulator (22) and also a signal generator (14) for applying to the acusto-optical element (8) an electrical signal (12) for splitting the beam (4). The device is intended to be developed to the effect that in conjunction with a simple and functionally reliable construction and independently of the number of beams emitted by the beam source (2), the intensity of the individual split partial beams (Ll, L2, L3, L4) can be kept constant. For this purpose, it is proposed that the modulator is embodied as an acusto-optical modulator (22) disposed downstream of the acusto-optical element (8), and that the acusto-optical modulator (22) is fed the split partial beams (Ll, L2, L3, L4) for modulation, and the acusto-optical modulator (22) can be driven with additional high-frequency electrical signals (Mf 1).