Twisted Kaleido Light Pipe for Lithography Illumination
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Solution Overview
Problem
Current lithography systems face challenges in achieving precise and cost-effective patterning on large area substrates for display devices, such as LCDs, due to non-uniform light distribution during the photolithography process.
Innovation Solution
A twisted light pipe, or kaleido, is used to homogenize light by reflecting it internally, ensuring uniformity at the output face, which is then utilized in an image projection apparatus to improve illumination uniformity over the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional illumination systems are used in lithography, then the system structure is simple, but the light distribution is non-uniform leading to poor patterning precision
Solution Approach 1:
A light pipe is introduced as an intermediary component between the light source and the substrate. The light pipe receives light from a point source and transforms it into a uniform distributed illumination across the substrate surface, thereby achieving high patterning precision without requiring a complex multi-source illumination system
Solution Approach 2:
The light pipe utilizes total internal reflection to change the propagation parameters of light rays. By controlling the refractive index and geometry of the light pipe, the light distribution parameters are transformed from a concentrated point source pattern to a uniform area illumination pattern, achieving both simplicity and precision
2Productivity
If conventional light sources are used without light homogenization, then the system is simple, but the illumination is non-uniform reducing productivity
Solution Approach 1:
The light pipe serves as a mediating optical element that homogenizes light distribution. It takes the non-uniform light from a simple point source and outputs uniform illumination across the entire substrate, thereby improving patterning efficiency without adding complex multi-source illumination systems
3Manufacturing precision
If a point light source is used directly, then the system complexity is low, but the light distribution uniformity is poor leading to reduced manufacturing precision
Solution Approach 1:
The light pipe changes the spatial distribution parameters of light through total internal reflection. The refractive index profile and geometric configuration of the light pipe transform the concentrated point source illumination into a uniform area illumination, achieving both high precision and uniformity simultaneously
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 twisted light pipe enhances light uniformity, leading to improved patterning precision and efficiency in photolithography processes, enabling the creation of high-quality display devices at reduced costs.
Implementation Method 1
The elongated rectangular body has a refractive index that provides total internal reflection within the elongated rectangular body
Data Source
AI summary
Implementations disclosed herein generally relate to a light pipe, or kaleido, for homogenizing light such that the light is uniform once the light exits the light pipe. By reflecting the light inside the light pipe, light uniformity is increased. In one implementation, a light pipe for an image projection apparatus is provided. The light pipe comprises an elongated rectangular body having a refractive index that provides total internal reflection within the elongated rectangular body. The elongated rectangular body has an input face for accepting light into the elongated rectangular body. The input face disposed substantially orthogonal to a longitudinal axis of the elongated rectangular body. The elongated rectangular body has an output face for releasing light from the elongated rectangular body. The output face is disposed substantially orthogonal to the longitudinal axis. The elongated rectangular body has a twist along the longitudinal axis.