Level Sensor Projection Unit with Dual Light Pipes for Uniform Irradiance
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Solution Overview
Problem
Current projection units in lithographic systems have low optical transmission efficiency, are complex with many parts, and high associated costs.
Innovation Solution
A projection unit comprising a first and second light pipe with tapering walls, a lens device, and a grating to achieve a predetermined distribution of intensity and irradiance, along with an image multiplier device to enhance the aspect ratio of radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional projection units are used in lithographic systems, then the system can perform pattern projection, but the optical transmission efficiency is low and the system complexity is high
Solution Approach 1:
The patent combines multiple optical functions (illumination, homogenization, and projection) into a single integrated light pipe assembly. The light pipe has a first end for receiving light from the source and a second end for projecting the light pattern, eliminating the need for separate illumination optics and reducing the number of optical components. This merging of functions directly improves optical transmission efficiency by reducing interfaces and alignments while simplifying the overall system structure.
Solution Approach 2:
The light pipe serves multiple functions simultaneously: it acts as an illumination conduit, a homogenizer for the light intensity distribution, and a projection element for creating the desired light pattern on the substrate. The light pipe's internal structure is designed to perform all these functions within a single component, reducing system complexity while maintaining or improving optical transmission efficiency.
2Ease of manufacture
If traditional projection units with many components are used, then various optical functions can be achieved, but the manufacturing cost increases
Solution Approach 1:
By merging multiple optical components into a single light pipe assembly, the patent reduces the number of manufacturing steps, alignments, and assemblies required. The integrated design eliminates the need for precise alignment of multiple separate optical elements, thereby reducing manufacturing complexity and cost while maintaining the necessary optical performance through the light pipe's internal structural design.
Solution Approach 2:
The light pipe incorporates specific geometric parameters including asymmetrical cross-sections, varying wall thicknesses, and internal surface treatments that enable it to perform multiple optical functions. By optimizing these geometric parameters during manufacturing, the single light pipe component achieves the optical performance previously requiring multiple components, thereby reducing cost while maintaining reliability.
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 increases optical transmission efficiency, reduces component count, and lowers costs by simplifying the illumination optics and light guide, achieving uniform and symmetrical intensity and irradiance distributions.
Implementation Method 1
a first light pipe having a first inlet configured to receive radiation from a source and a first outlet; and a second light pipe having a second inlet configured to receive the radiation from the first light pipe and a second outlet
Data Source
AI summary
A projection unit for a level sensor, the projection unit including: a first light pipe having a first inlet configured to receive radiation from a source and a first outlet; and a second light pipe having a second inlet configured to receive the radiation from the first light pipe and a second outlet. The unit may include a lens device configured to receive radiation from the second outlet and to output radiation having a predetermined distribution of intensity and irradiance.