LED Exposure Optics With Irradiance Superposition for Fine Patterns
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Solution Overview
Problem
Conventional exposure apparatuses using LEDs as light sources suffer from low light utilization efficiency, particularly when narrowing the aperture diaphragm for higher resolution, leading to insufficient irradiance and longer exposure times.
Innovation Solution
A lighting optical system comprising a light source with aligned light-emitting elements, a relay optical system for superimposing irradiance distributions, an optical integrator with wavefront splitting elements, and a condenser optical system to enhance light superposition and utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple LEDs are used as light source, then the light output can be increased, but the light utilization efficiency becomes low
Solution Approach 1:
The patent merges light from multiple LED chips through a relay optical system that superimposes their images onto a single incident surface of the optical integrator. This combining approach allows the system to achieve high light output from multiple LEDs while maintaining efficient light utilization by directing all light through a unified optical path to the workpiece surface.
2Measurement precision
If aperture diaphragm is narrowed to increase exposure resolution, then the exposure resolution is improved, but the irradiance on the surface to be irradiated becomes insufficient
Solution Approach 1:
The patent addresses the irradiance insufficiency by utilizing the spatial dimension through image superposition. Multiple LED images are superimposed in the optical integrator, effectively distributing light from multiple sources across the aperture diaphragm opening. This allows the aperture to be narrowed for high resolution while maintaining sufficient irradiance through the combined light from multiple superimposed LED images.
3Measurement precision
If aperture diaphragm is narrowed to increase exposure resolution, then the exposure resolution is improved, but the exposure time becomes longer
Solution Approach 1:
The patent combines light from multiple LED chips through image superposition in the optical integrator. This merging of light sources increases the total light throughput that can pass through the aperture diaphragm, allowing the system to maintain narrow aperture settings for high resolution exposure while compensating for the reduced light transmission with increased light intensity from multiple superimposed sources, thereby reducing exposure time.
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 system achieves higher light utilization efficiency, allowing for reduced exposure time and improved irradiance distribution, especially suitable for finer patterns.
Implementation Method 1
a relay optical system configured to convert a luminous intensity distribution of light emitted from each of the light-emitting elements into an irradiance distribution and to superimpose a plurality of the irradiance distributions corresponding to the plurality of light-emitting elements on each other on a superimposed surface
Implementation Method 2
an optical integrator having a plurality of wavefront splitting elements arranged in parallel to each other, the plurality of wavefront splitting elements being configured to wavefront split irradiated light through the relay optical system and to transmit the wavefront split light as a plurality of pencils of light rays
Implementation Method 3
a condenser optical system configured to superimpose the plurality of pencils of light rays on each other on a surface to be irradiated
Data Source
AI summary
Disclosed herein is a lighting optical system comprising: a light source having a plurality of light-emitting elements configured to emit light from light-emitting surfaces, respectively; a relay optical system configured to convert a luminous intensity distribution of light emitted from each of the light-emitting elements into an irradiance distribution and to superimpose a plurality of the irradiance distributions corresponding to the plurality of light-emitting elements on each other on a superimposed surface; an optical integrator having a plurality of wavefront splitting elements arranged in parallel to each other, the plurality of wavefront splitting elements being configured to wavefront split irradiated light through the relay optical system and to transmit the wavefront split light as a plurality of pencils of light rays; and a condenser optical system configured to superimpose the plurality of pencils of light rays on each other on a surface to be irradiated.