Shaping Optical System for Laser Spot Ellipticity Control
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Solution Overview
Problem
Existing optical processing apparatuses fail to achieve good beam quality capable of microfabrication due to inadequate control over the spot shape of the laser beam near the processed surface, particularly in terms of ellipticity, which affects processing accuracy.
Innovation Solution
An optical processing apparatus with a shaping optical system that adjusts the focal positions of a concavo-convex cylindrical lens system to minimize the ratio of major to minor axis diameters of the laser beam spot shape at or near the focal position, ensuring a more circular spot shape and improved beam quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a diffractive optical element or astigmatism optical system is used to shape the laser beam spot, then the processing area is enlarged, but the spot shape becomes elliptical and beam quality deteriorates
Solution Approach 1:
The patent divides the beam shaping function into two independent parts: the shaping optical system for creating the desired spot shape and the condensing optical system for focusing the beam. This segmentation allows each system to be optimized independently, enabling good beam quality to be maintained while achieving the desired processing area through proper shaping without compromising focus quality.
Solution Approach 2:
The patent addresses the spot shape control by introducing a specific dimensional constraint: making the spot shape circular (equal dimensions in all directions) at the focal position rather than elliptical. This dimensional approach ensures that the beam maintains good quality for microfabrication while the shaping system can still provide adequate processing area.
2Manufacturing precision
If the spot shape is shaped to have low ellipticity for good beam quality, then microfabrication capability is improved, but the processing area is reduced
Solution Approach 1:
By separating the shaping and condensing functions into independent optical systems, the patent allows the shaping system to create a circular spot profile for good beam quality while the condensing system ensures proper focusing. This enables microfabrication capability to be maintained without unnecessarily limiting the processing area, as the shaped beam can be properly utilized.
Solution Approach 2:
The patent changes the spot shape parameter from elliptical to circular by properly designing the shaping optical system. This parameter change (achieving equal major and minor axis diameters at the focal position) improves beam quality for microfabrication while the system configuration ensures the processing area remains adequate through proper optical design.
3Adaptability or versatility
If the processing surface height varies, then adaptability is improved, but spot shape stability deteriorates
Solution Approach 1:
The patent separates the shaping optical system from the condensing optical system, allowing the shaping system to establish a stable circular spot profile that is then properly focused by the condensing system. This segmentation enables the system to adapt to varying surface heights while maintaining spot shape stability, as each system can be independently optimized for its specific function.
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 configuration enhances processing accuracy by maintaining a stable spot shape close to a perfect circle, even when the processing surface height varies, thereby improving microfabrication capabilities and reducing ellipticity.
Implementation Method 1
a condensing optical system, which condenses the light emitted from the light source on a processing target position on a surface of the object to be processed
Implementation Method 2
a shaping optical system, which shapes a cross-sectional shape of the condensed light in a plane perpendicular to an optical axis of the condensed light that processes the object... a focal optical system which differentiates a focal position according to a position in a predetermined direction
Data Source
AI summary
An optical processing apparatus includes a light source, a condensing optical system, and a shaping optical system. The light source emits light. The condensing optical system condenses the light emitted from the light source onto a processing target position on a surface of an object to be processed. The shaping optical system shapes a spot shape of the condensed light, such that a ratio of a major axis diameter of the spot shape to a minor axis diameter of the spot shape, in a cross section orthogonal to an optical axis of the condensed light on the object to be processed, is a minimum at or adjacent to a focal position of the shaping optical system. A method for optically processing an object is also provided.