Laser Focal Length Adjustment Using Orthogonal Stepper Drive
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Solution Overview
Problem
Existing laser processing devices face challenges in achieving precise and efficient focal length adjustment due to limitations in magnetic force-based systems, stepper motor-driven mechanisms, and manual adjustment methods, which hinder high-speed processing and accurate focal point control.
Innovation Solution
A focal length adjusting device with a retainer, guide, and stepper motor that converts rotational motion to linear motion, allowing precise adjustment of the distance between two lenses to control the focal length of a laser beam, enabling high-precision focal length adjustment without the need for complex machining or additional space-consuming components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If magnetic force is used to move the lens, then the lens can be moved, but the system requires additional space for generating magnetic force and is not suitable for fine adjustment
Solution Approach 1:
The patent replaces the magnetic force-based drive system with a mechanical drive system using a lead screw and nut mechanism. The lead screw is rotated by a positioning mechanism to convert rotational motion into linear motion of the lens holder, eliminating the need for magnetic force generation components and reducing overall system space while enabling precise positional control of the lens.
2Measurement precision
If a feed screw and single-axis table are used to move the lens, then the lens can be positioned, but complicated precision machining is required and play between components causes positioning errors
Solution Approach 1:
The patent applies local quality by focusing precision requirements only on the critical lead screw and nut interface where motion conversion occurs, rather than requiring precision machining throughout the entire single-axis table structure. The lead screw and nut are designed with high precision to minimize play, while other structural components can be manufactured with standard tolerances, reducing overall manufacturing complexity.
Solution Approach 2:
The patent introduces a preloading mechanism that applies axial force to the lead screw-nut assembly to eliminate clearance and play between components. This dynamic preloading ensures consistent contact between the screw threads and nut, maintaining positioning accuracy during lens movement without requiring excessively tight manufacturing tolerances throughout the entire mechanism.
3Ease of operation
If manual adjustment is performed with a tapered structure, then the lens can be moved, but automation is difficult and the lens may not be positioned as intended
Solution Approach 1:
The patent replaces the manual tapered structure adjustment mechanism with an automated lead screw-driven system. The lead screw can be rotated by various actuation methods including stepper motors, servo motors, or other positioning mechanisms, enabling automated control of lens position. The direct mechanical coupling between the lead screw and lens holder through the nut ensures predictable and accurate positioning without the ambiguity of manual adjustment.
4Productivity
If the focal position is frequently adjusted, then high-speed processing is enabled, but existing mechanisms have play that causes different positioning when moved toward and away from the motor
Solution Approach 1:
The patent implements a preloading mechanism that maintains constant axial force on the lead screw-nut assembly during bidirectional movement. This dynamic preloading eliminates clearance and ensures that the lens holder is positioned accurately whether moving toward or away from the drive mechanism, enabling reliable frequent adjustments for high-speed processing without positioning errors from mechanical play.
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 solution enables precise and efficient adjustment of the focal length of a laser beam, improving processing accuracy and speed, while reducing the size and weight of the focal length adjusting device, thus addressing the limitations of existing technologies.
Implementation Method 1
a converter located between the shaft and the retainer to convert rotational motion of the shaft to linear motion of the retainer
Data Source
AI summary
A focal length adjusting device is provided with: a retention unit for retaining a first lens; a guide unit for supporting the retention unit so as to allow movement along an optical axis of laser light; a stepper motor that has a shaft body and is arranged so that the central axis of the shaft body is orthogonal to the optical axis; and a conversion unit that is interposed between the shaft body and the retention unit and converts rotational movement of the shaft body into linear movement of the retention unit. The conversion unit comprises, between itself and the retention unit, a coupling unit that transmits kinetic force from the conversion unit to the retention unit in a direction parallel to the optical axis but does not transmit same in a direction parallel to the central axis of the shaft body.