Laser Ablation Head with Rotating Prism for Precise Beam Scanning
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Solution Overview
Problem
Current laser ablation tools face challenges in restricted areas like gas turbine engines due to fragility and limited control of MEMS devices and fixed diffractive optical elements, which restrict precise ablation and beam intensity.
Innovation Solution
A laser ablation tool utilizing a pulsed laser source coupled with a rotating prism and moveable mirror, mounted on a borescope or flexible arm, allowing for controlled beam scanning and increased area coverage through a combination of optical fibre and movable optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a MEMS device is used to manipulate the laser beam, then beam control capability is improved, but device fragility and reliability deteriorate
Solution Approach 1:
The patent replaces the mechanical MEMS device with an acousto-optic modulator (AOM) that uses acoustic waves to diffract and control the laser beam. This substitution eliminates fragile moving mechanical parts while maintaining beam manipulation capability through acoustic field control.
Solution Approach 2:
The patent introduces an acousto-optic modulator as an intermediary device between the laser source and the workpiece. The AOM uses sound waves as a mediator to control the laser beam path and intensity, avoiding direct mechanical contact and reducing fragility issues.
2Shape
If a fixed diffractive optical element is used, then beam shaping capability is improved, but adaptability and on-the-fly adjustment capability deteriorate
Solution Approach 1:
The patent replaces the fixed diffractive optical element with an acousto-optic modulator that can dynamically change its diffraction pattern in real-time by adjusting the acoustic frequency and amplitude. This enables on-the-fly adjustment of beam profile and position without physical reconfiguration.
Solution Approach 2:
The patent utilizes the ability to change acoustic parameters (frequency, amplitude, modulation depth) of the AOM to dynamically alter the laser beam characteristics. By changing these parameters, the system can adapt beam shape, position, and intensity without physical modification of the optical element.
3Area of stationary object
If the laser beam is spread over a large area, then coverage area is improved, but beam intensity and ablation effectiveness deteriorate
Solution Approach 1:
The patent uses pulsed laser operation combined with rapid acoustic modulation in the AOM to scan the beam across the surface in a periodic manner. This allows concentration of high energy in small pulses at each location while covering a larger overall area through repeated scanning patterns.
Solution Approach 2:
The patent employs dynamic beam scanning controlled by the acousto-optic modulator to rapidly move the focused laser spot across the workpiece surface. This dynamic scanning enables coverage of large areas while maintaining high beam intensity at each instantaneous point by concentrating energy in a small focal spot that moves quickly.
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
Enables robust, controlled, and efficient ablation over larger areas with precise beam control, reducing fragility and maintaining sufficient beam intensity, suitable for complex environments like gas turbine engines.
Implementation Method 1
the light from the laser source being coupled to the head using an optical fibre
Implementation Method 2
a prism that rotates by use of a rotation mechanism with the prism being located in a plane perpendicular to the axis of light from the laser source
Implementation Method 3
a mirror that is moveable in at least one direction and which is set at an angle relative to the axis of light from the laser source
Implementation Method 4
Laser ablation uses a beam from a laser to heat up and vaporise a selected area of the component
Implementation Method 5
heat up and vaporise a selected area of the component
Data Source
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AI summary
A laser ablation tool comprising, a pulsed laser source, a prism (24) that rotates in a plane perpendicular to light from the laser source, and a mirror (25) that is moveable in at least one direction and which is set at an angle relative to the light from the laser source.