Projection Beam Control With Circular Scanning for Uniform Pixels
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Solution Overview
Problem
Conventional beam deflecting devices face challenges such as high mechanical inertia, irregular scanning speed, and difficulty in achieving uniform pixel distribution due to resonant frequency differences, leading to issues like irregular edges in material processing and inefficient image projection.
Innovation Solution
A control unit is used to control a projection device with two light beam deflection units, where the deflection frequencies are set to be nearly equal, allowing the light spot to move along a nearly circular path, enabling efficient scanning of an imaging area with a simple time-to-space mapping and maintaining precision and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If resonant circuits are used to increase voltage applied to electro-optic crystal, then operating voltage can be reduced, but frequency range is limited to small range around resonance frequency
Solution Approach 1:
The system dynamically adjusts the amplitude of the resonant signal over time, transitioning from a static resonant state to a time-varying amplitude state. This allows the system to maintain resonance benefits while adapting the scanning pattern to achieve uniform pixel distribution across the imaging area.
Solution Approach 2:
The invention changes the amplitude parameter of the resonant signal over time, creating a time-varying deflection pattern. By modulating the amplitude of the resonant oscillation, the system can scan different radial distances from the center, ensuring uniform pixel distribution while operating at a fixed resonant frequency.
2Speed
If resonant mode is used for beam deflection, then scanning speed increases, but pixel distribution becomes non-uniform with higher density at borders
Solution Approach 1:
The system employs dynamic amplitude modulation of the resonant signal, where the amplitude varies over time to create a scanning pattern that spends equal time sampling each pixel. This dynamic adjustment compensates for the varying tangential speed at different radial positions, achieving uniform pixel distribution while maintaining high scanning speeds.
Solution Approach 2:
The invention implements a feedback mechanism where the amplitude of the resonant signal is adjusted based on the desired pixel distribution pattern. By monitoring the scanning position and adjusting the amplitude accordingly, the system ensures that each pixel is sampled uniformly, correcting the natural non-uniform distribution that would occur with simple resonant oscillation.
3Ease of operation
If two deflectors with different resonant frequencies are combined for two-dimensional deflection, then frequency ratio must be defined by integer quotient, but this limits the usable imaging area to about 60% of lateral dimensions
Solution Approach 1:
The system uses dynamic amplitude modulation to overcome the limitations of fixed resonant frequency ratios. By varying the amplitude of the resonant oscillation over time, the system can access a broader imaging area without being constrained by integer frequency ratios, effectively utilizing more than 60% of the available lateral dimensions.
Solution Approach 2:
The invention adds the time dimension to the deflection control by modulating the amplitude of the resonant signal. This temporal dimension allows the system to sweep through different radial positions during each resonant cycle, effectively creating a spiral or radial scanning pattern that expands the usable imaging area beyond what is possible with static amplitude operation.
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 allows for a significant increase in the area that can be reached by the light beam while maintaining precision and speed, achieving a more uniform pixel distribution and improved image projection quality.
Implementation Method 1
Electro-optic deflectors use crystals made of a material exhibiting an electro-optic effect. When a voltage gradient is applied to the crystal, a light beam propagating through the crystal is deflected.
Implementation Method 2
resonant circuits have been proposed to increase the voltage applied to the electro-optic crystal. Such resonantly enhanced electro-optic modulators may be operated with smaller external voltages because the high voltages required for the operation are internally generated.
Data Source
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Figure 7a~8
AI summary
A control unit (130) is provided for controlling a projection device (100) for directing a light beam (101) to a target (140). The projection device (100) comprises a light beam deflection unit (120) for two-dimensionally deflecting a light beam (101) in a first direction (x) with a first deflection frequency and in a second direction (y) with a second deflection frequency substantially equal to the first deflection frequency. The control unit (130) is configured to control the deflection unit (120) in such a way that a light spot (141) generated by the light beam (101) on the target (140) moves along a nearly circular path (144) changing its radius (R) over time.