Elastomeric Flexural Elements for Laser Scanning Beam Stability
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Solution Overview
Problem
Conventional laser scanning assemblies suffer from issues such as beam shifting, unwanted tilting, and distortion due to gravity and operator movement, especially in portable applications, and require tedious adjustments and are prone to damage from rough handling.
Innovation Solution
A laser scanning assembly using an injection-molded elastomeric flexural element made of silicone, mounted between a mirror and magnet subassembly and a drive coil support element, which provides a balanced and resilient structure that maintains beam stability and accuracy by supporting the mirror and magnet in a parallel manner, allowing for smooth scanning without a pole piece and being resistant to temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional flexural elements made from plastic film or flexible materials are used, then the scanning assembly can be manufactured with simple structures, but the scan mirror experiences unwanted tilting or drooping when held in different orientations due to gravity
Solution Approach 1:
The patent changes the material parameter from conventional plastic film to elastomeric material (such as silicone rubber), which provides both flexibility for manufacturing and sufficient structural integrity to resist gravitational effects. This material parameter change enables the flexural element to maintain beam stability while remaining manufacturable.
Solution Approach 2:
The patent employs composite construction by combining elastomeric material with rigid components (scan mirror, magnet assembly, drive coil support). This composite approach allows the flexible elastomeric flexural element to support rigid optical and magnetic components while maintaining stability against gravity and enabling easy manufacturing through automated molding techniques.
2Length of moving object
If large scan mirrors are used for long range scanning, then the scanning range is improved, but the unwanted tilting or drooping due to gravity is exacerbated
Solution Approach 1:
The patent changes the material properties of the flexural element from conventional flexible materials to elastomeric material with higher structural integrity. This parameter change enables the support of larger scan mirrors required for long-range scanning while maintaining beam stability and resistance to gravitational tilting.
3Strength
If the device is subjected to rough handling or drops, then the durability should be improved, but the flexible film flexural elements become permanently distorted producing shifted scan lines
Solution Approach 1:
The patent changes the material from conventional plastic film to elastomeric material (such as silicone rubber) with superior elastic recovery properties. This parameter change enables the flexural element to withstand rough handling and drops without permanent distortion, maintaining scan line accuracy while improving durability.
Solution Approach 2:
The elastomeric flexural element inherently provides shock absorption and cushioning against rough handling and drops. The material's elasticity allows it to absorb impact energy and return to its original configuration, preventing permanent distortion that would otherwise occur with conventional flexible materials.
4Force
If an inductive pole piece is added within the electromagnetic drive coil to generate magnetic bias, then the magnetic field is improved, but beam shifting and unwanted forces occur resulting in undesirable speed perturbations
Solution Approach 1:
The patent removes (takes out) the inductive pole piece from the electromagnetic drive coil assembly. By eliminating this component, the unwanted magnetic bias that caused beam shifting and speed perturbations is removed, while the drive coil can still generate sufficient magnetic force for scanning operation.
5Use of energy by moving object
If a pulse of current such as a short duty cycle square wave is used as drive waveform, then the energy efficiency is improved, but radical bursts of acceleration and deceleration occur distorting the timing of light signals
Solution Approach 1:
The patent changes the drive waveform parameters from short duty cycle square wave to longer duty cycle waveforms (such as triangular or sinusoidal waves). This parameter change reduces radical acceleration and deceleration bursts, improving signal timing accuracy while maintaining reasonable energy efficiency for portable scanning applications.
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 assembly achieves high immunity to irregular scan speed, beam shifting, and damage, providing stable and accurate scanning with non-jerky speed characteristics, and can be economically assembled using automated manufacturing techniques.
Implementation Method 1
at least one elastomeric flexural element... providing a return force when the permanent magnet and the mirror are rotated at an angle from the central axis during energization of the electromagnetic wire coil
Implementation Method 2
an energizable electromagnetic wire coil... when an electrical current is supplied to the drive coil at an appropriate frequency, waveform and amplitude
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A laser scanning assembly includes a coil support element having a central axis about which is wound an electromagnetic wire coil and having a flange oriented generally transverse to the central axis. At least one elastomeric flexural element has a first end coupled to the flange. A permanent magnet has first and second surfaces, a central axis, and a magnetization direction oriented generally transverse to the central axis of the permanent magnet. The magnet is supported by a second end of the elastomeric flexural element. A mirror has a central axis and is mounted on the second surface of the magnet. The central axes of the mirror and magnet are coaxial with the central axis of the coil support element. The elastomeric flexural element provides a return force when the magnet and the mirror are rotated at an angle from the central axis during energization of the electromagnetic wire coil.