Rotating Target Holder Layout for Stable Plasma Light Extraction
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Solution Overview
Problem
Vibrations and deformations during the rotation of target holding units in light source apparatuses cause instability in the relative positions of light emission points and optical members, leading to inconsistent light extraction.
Innovation Solution
A light source apparatus with a target holding unit and drive unit that moves the holding surface along a treatment surface, including plasma formation, supply, and observation positions, with debris shields and a controlled rotational axis to stabilize the target material and reduce debris impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the target holding unit rotates at high speed to maintain target material on the holding surface, then the productivity and light generation efficiency are improved, but vibrations and deformations occur causing instability in the relative positions of light emission points and optical members
Solution Approach 1:
The treatment surface is divided into multiple functional positions (plasma formation position, supply position, observation position) arranged along the rotation direction. This segmentation allows different processes to occur at different locations, reducing interference between them and maintaining stability despite high-speed rotation.
Solution Approach 2:
The patent transitions from a static target holding configuration to a rotational one, adding the time dimension through cyclic motion. By arranging positions along the rotation direction and using the rotational movement to transport target material, the system achieves both high productivity and position stability through dimensional transformation.
2Ease of operation
If the target holding unit rotates to transport target material, then the ease of operation and material supply are improved, but debris is generated and scattered affecting the optical members
Solution Approach 1:
The harmful debris is extracted and isolated from the optical path by positioning the supply position downstream from the plasma formation position in the rotation direction. Debris generated during target material supply is carried away from the optical members by the rotational movement, preventing contamination.
Solution Approach 2:
The rotational movement of the target holding unit itself serves as an intermediary mechanism that both transports target material (beneficial function) and carries away debris (harmful function). This single rotational motion simultaneously achieves material supply and debris removal without requiring additional components.
3Measurement precision
If the observation position is placed to monitor the holding surface, then the measurement precision is improved, but the position becomes vulnerable to debris impact and thermal deformation
Solution Approach 1:
The observation position is strategically positioned upstream relative to the supply position in the rotation direction, allowing observation to occur before target material is supplied. This preliminary observation avoids exposure to debris generated during supply while maintaining measurement capability.
Solution Approach 2:
Different regions of the treatment surface are assigned different functions based on their exposure characteristics. The observation position is located in a region with lower debris exposure, while the supply position handles material loading. This local differentiation optimizes each position for its specific function while minimizing harmful exposures.
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
Stabilizes light extraction by maintaining consistent relative positions and reducing debris interference, enhancing the stability and accuracy of light generation.
Implementation Method 1
the target holding unit may have a rotational axis, and the drive unit may transport the target material to the target holding unit by rotating the target holding unit around the rotational axis
Implementation Method 2
a formation unit that excites the target material at the plasma formation position by focusing laser light on the target material
Implementation Method 3
irradiates the formed target material with excitation light, thereby extracting illumination light
Data Source
AI summary
A light source apparatus according to the present disclosure includes: a target holding unit that has a holding surface for transporting a target material for generating plasma, to at least one plasma formation position; and a drive unit that drives the target holding unit, and moves the holding surface, wherein the holding surface moves with respect to a treatment surface in a space along the holding surface, the treatment surface includes: at least one plasma formation position; at least one supply position at which the target material is supplied to the holding surface; and at least one observation position at which state information on the target material held on the holding surface, the plasma formation position, the supply position, and the observation position are disposed along the treatment surface, and the treatment surface includes the supply position disposed after the plasma formation position.