Beam Expander Linear Drive for Low-Backlash Optical Alignment
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Solution Overview
Problem
Existing beam expanders face challenges in achieving precise alignment and minimizing backlash during the adjustment of optical elements, leading to potential tilting and beampointing errors, particularly in laser material processing applications.
Innovation Solution
A beam expander design utilizing a linear drive coupling unit with two rotationally fixed nuts and a guide unit, combined with a lever and springs, minimizes tilting and backlash by ensuring precise movement of optical units within a receiving tube, using widely available components with non-critical tolerance requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple linear drive coupling unit with single nut is used, then manufacturing cost and complexity are reduced, but backlash and tilting increase
Solution Approach 1:
The linear drive coupling unit is segmented into two separate nuts instead of using a single nut. Each nut engages with the threaded rod independently, allowing the system to minimize tilting and backlash by distributing the mechanical load and constraint across two discrete engagement points, thereby improving alignment precision without significantly increasing overall structural complexity
Solution Approach 2:
The guide unit acts as an intermediary element between the linear drive coupling unit and the optical unit. It translates the linear motion from the threaded rod into precise movement of the optical unit while constraining unwanted tilting and rotation, thus mediating the relationship between the drive mechanism and the optical component to achieve high alignment precision
2Ease of manufacture
If the optical unit is movably mounted with standard components, then ease of manufacture and cost-effectiveness are improved, but backlash and beampointing errors increase
Solution Approach 1:
The guide unit is designed to preliminarily constrain the optical unit's movement path before the actual beam expansion operation begins. By pre-establishing a precise movement trajectory through the guide unit's mechanical constraints, the system prevents backlash and tilting from affecting beam quality during operation, even when using standard movable mounting components
Solution Approach 2:
The patent replaces complex precision mechanical mounting systems with a simpler combination of a threaded rod drive mechanism and a guide unit. This substitution achieves high reliability by using the threaded rod's inherent precision and the guide unit's mechanical constraints rather than relying on expensive precision bearings or adjustable mounting mechanisms
3Manufacturing precision
If the threaded rod section engaged by nuts is made longer, then backlash is minimized, but device length increases
Solution Approach 1:
The two nuts are arranged in the axial dimension at different positions along the threaded rod. This spatial distribution in the axial direction allows the engaged section length to be optimized for minimal backlash while keeping the overall compactness of the drive coupling unit. The axial arrangement of multiple engagement points effectively increases the constrained length without proportionally increasing the radial or overall device dimensions
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 design achieves minimal backlash and tilting, allowing for precise alignment and high-speed operation with reduced wear, maintaining beam quality and reducing beampointing errors, while being cost-effective and efficient.
Implementation Method 1
The linear drive coupling unit has at least two spaced-apart nuts that are coupled or can be coupled to a threaded rod as the drive element and/or are designed to effect a linear movement of the guide unit when the threaded rod as the drive element rotates
Implementation Method 2
the guide unit can have at least one lever extending at least partially in the direction of movement of the guide unit, as well as a spring that is tensioned or tensionable between one end of the lever and the linear drive coupling unit
Data Source
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AI summary
The invention relates to a beam expander (100) comprising a receiving tube (105) with a light inlet opening (107) and a light outlet opening (109). The beam expander (100) additionally comprises at least one optical unit (112), which is movably arranged in a beam path between the light inlet opening (107) and the light outlet opening (109) of the receiving tube (105) in a movement direction (117), for changing the diameter of a beam bundle (110) coupled in via the light inlet opening (107). The beam expander (100) also comprises a guide unit (120), which is coupled to the optical unit (112), for guiding the optical unit (112) in the receiving tube (105) and a linear drive coupling unit (125), which is mechanically coupled to the guide unit (120), in order to couple and/or convert a movement or rotation of a drive element (127) into a movement of the guide unit (120).