Switchable Blaze Grating Stack for Large-Angle Beam Deflection
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Solution Overview
Problem
Existing beam deflection technologies, such as polarization gratings and switchable Bragg gratings, face limitations in achieving large deflection angles with high diffraction efficiency due to complex structures and restricted angle ranges, making them unsuitable for large fields of view and efficient scanning.
Innovation Solution
An optoelectronic sensor employing a stack of switchable blaze gratings with varying grating constants and blaze angles, where at least two gratings share the same grating constant to cover a broader range of angles, allowing for large deflection angles without compromising diffraction efficiency, and a control unit switches gratings on/off to achieve desired deflection angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If polarization gratings or switchable Bragg gratings are used for beam deflection, then beam deflection is achieved, but the structure becomes complex and expensive requiring two to four layers of liquid crystal elements per grating
Solution Approach 1:
The patent divides the beam deflection function into multiple independent blaze gratings with different grating constants, where each grating can be switched on or off independently. This segmentation allows the system to achieve various deflection angles by combining different grating configurations, reducing the need for complex multi-layer structures while maintaining diffraction efficiency through selective activation of appropriate gratings.
Solution Approach 2:
The patent utilizes blaze gratings with different grating constants (e.g., 120 lines/mm, 60 lines/mm, 30 lines/mm) that can be selectively activated by changing electrical parameters. By varying the grating constant parameter across different blaze gratings, the system achieves different deflection angles without requiring complex structural changes, thereby simplifying the overall device while maintaining high diffraction efficiency.
2Device complexity
If a single blaze grating is used for beam deflection, then the structure is simple, but the range of deflection angles is limited
Solution Approach 1:
The patent segments the beam deflection capability across multiple blaze gratings with different grating constants. Each grating is responsible for a specific deflection angle range, and by combining multiple gratings, the system achieves a comprehensive angular range while keeping each individual grating simple in structure.
Solution Approach 2:
The patent creates a multi-functional beam deflection system where multiple blaze gratings can be selectively activated to perform different deflection functions. The same physical structure (stack of gratings) can achieve various deflection angles by switching different gratings, making the system universally applicable for different scanning requirements without adding complex components.
3Ease of operation
If mechanical scanning mechanisms are used, then beam deflection is achieved, but construction size and shock sensitivity increase along with servicing susceptibility
Solution Approach 1:
The patent replaces mechanical scanning mechanisms (rotating mirrors, mirror wheels) with a solid-state optical system using switchable blaze gratings. The beam deflection is achieved through optical means (diffraction from gratings) rather than mechanical movement, eliminating moving parts, reducing shock sensitivity, and removing the need for mechanical servicing while maintaining full beam deflection capability.
Solution Approach 2:
The blaze grating system is self-contained with no external mechanical components. The gratings are integrated directly into the optical path and can be switched on or off through electrical control without requiring external mechanical actuators or scanning mechanisms, making the system self-sufficient and eliminating maintenance requirements associated with mechanical parts.
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 setup enables a solid-state scanner with improved efficiency and a large scanning angle, reducing mechanical parts and complexity, enhancing signal-to-noise ratio, and allowing for larger fields of view up to 30° or more without sacrificing diffraction efficiency.
Implementation Method 1
a beam deflection device having a plurality of switchable blaze gratings of different grating constants arranged behind one another
Implementation Method 2
switchable blaze gratings of different grating constants arranged behind one another
Data Source
AI summary
An optoelectronic sensor is provided having a light receiver, a reception optics arranged upstream of the light receiver, and a control and evaluation unit, wherein the reception optics has a beam deflection device having a plurality of switchable blaze gratings of different grating constants arranged behind one another, and wherein the control and evaluation unit is configured to switch a blaze grating on and off in accordance with a desired deflection angle of the beam deflection device have the same grating constants, but a mutually different blaze angle.