Laser Beam Shaping with Diffractive Optic Element and Zeroth-Order Light Removal
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Solution Overview
Problem
The use of diffractive optic elements to shape laser beams results in a reduction in processing performance due to the presence of zeroth-order light, which is not converted into first-order light.
Innovation Solution
A laser beam applying apparatus that includes a diffractive optic element and zeroth-order light removing means, comprising a first prism, a second prism with a zeroth-order light reflecting surface, and a damper, to separate and absorb zeroth-order light, ensuring only first-order light with a defined spot shape is focused onto the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a diffractive optic element is used to form the spot shape of the laser beam into a predetermined shape, then the spot shape definition is improved, but zeroth-order light is not removed causing a reduction in processing performance
Solution Approach 1:
The patent extracts and removes the harmful zeroth-order light from the optical path using a beam splitter and absorber, while retaining the useful first-order light that carries the defined spot shape. This separation resolves the contradiction by eliminating the harmful component that degrades processing performance while preserving the beneficial spot shaping capability.
Solution Approach 2:
The patent introduces a beam splitter as an intermediary component between the diffractive optic element and the workpiece. The beam splitter mediates the separation of zeroth-order and first-order light, enabling selective transmission of useful light while directing harmful light to an absorber, thus resolving the performance degradation issue.
2Ease of manufacture
If zeroth-order light is present in the laser beam, then the diffractive optic element can be used for spot shaping, but processing performance is reduced
Solution Approach 1:
The patent extracts the harmful zeroth-order light from the combined beam using a beam splitter positioned at a specific angle. The beam splitter reflects the zeroth-order light toward an absorber while allowing the first-order light to pass through to the workpiece, thereby maintaining spot shaping capability while eliminating performance degradation.
Solution Approach 2:
The patent converts the harmful zeroth-order light into a beneficial separation mechanism. By using the angular difference between zeroth-order and first-order light, the system uses the harmful component's directionality to facilitate its own removal, while the remaining first-order light provides the desired spot shaping without performance loss.
3Manufacturing precision
If the diffractive optic element is used to define the spot shape, then the laser beam can be shaped into first-order light, but zeroth-order light remains causing performance reduction
Solution Approach 1:
The beam splitter acts as an intermediary that separates the light paths based on the angular difference between zeroth-order and first-order light. This mediation enables the system to maintain high spot shape accuracy while improving processing efficiency by eliminating the harmful zeroth-order light that would otherwise reduce overall productivity.
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 prevents the reduction in processing performance caused by zeroth-order light, maintaining high accuracy in laser processing by eliminating unnecessary light, thereby enhancing the overall processing efficiency.
Implementation Method 1
a diffractive optic element (DOE) is also known... first-order light is formed by the diffractive optic element
Implementation Method 2
a first prism having an incident surface on which the first-order light and the zeroth-order light are incident and an emergent surface from which the first-order light and the zeroth-order light emerge so as to be angularly shifted from each other
Implementation Method 3
a second prism having a zeroth-order light reflecting surface for allowing the incidence of the first-order light emerged from the emergent surface of the first prism and reflecting the zeroth-order light emerged from the emergent surface of the first prism
Implementation Method 4
a damper for absorbing the zeroth-order light reflected on the zeroth-order light reflecting surface of the second prism
Implementation Method 5
a focusing lens for focusing the laser beam oscillated by the laser beam oscillating means
Data Source
AI summary
A laser beam applying apparatus includes a laser beam oscillating unit, a focusing lens, and a diffractive optic element provided between the laser beam oscillating unit and the focusing lens for defining the spot shape of the laser beam oscillated by the laser beam oscillating unit. A zeroth-order light removing unit removes zeroth-order light emerging from the diffractive optic element and leaves first-order light whose spot shape has been defined by the diffractive optic element and the focusing lens. A first prism has an incident surface and an emergent surface inclined with respect to the incident surface. A second prism has a zeroth-order light reflecting surface for reflecting the zeroth-order light and a first-order light emerging surface from which the first-order light emerges. A damper absorbs the zeroth-order light reflected on the zeroth-order light reflecting surface of the second prism.