Oblique Illumination Apparatus with Rotated Optical Elements

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing illumination systems for micro-mirror devices in optical systems require a shine-proof optical system for oblique illumination, which increases the cost and size of the apparatus due to the need for multiple lenses, compromising efficiency.

Innovation Solution

An illumination apparatus using a first optical element with an array of optical components generating point light sources and a second optical element forming an illumination region with differing power directions, where at least one element is rotated about its optical axis to compensate for distortion, eliminating the need for a shine-proof optical system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a shine-proof optical system is used for oblique illumination of micro-mirror device, then illumination quality is maintained, but apparatus cost and size increase due to multiple lenses

Engineering Contradiction:

Improveillumination qualityVSAvoidapparatus size and cost

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the shine-proof optical system (multiple lenses) from the illumination path by using oblique illumination geometry where the illumination optical system and observation optical system are separated in space, achieving simple illumination without compromising image quality

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transitions from normal illumination to oblique illumination, changing the dimensional arrangement of optical components. The illumination light enters the micro-mirror device from an oblique angle rather than perpendicularly, allowing the illumination optical system to be positioned in a different spatial plane and eliminating the need for complex shine-proof optics

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

This solution enables oblique illumination with high efficiency without increasing the apparatus' cost or size, maintaining illumination quality by compensating for distortion through rotation of optical elements.

Implementation Method 1

a first optical element formed with an array of a plurality of optical components each configured to generate a point light source

Methodology Applied

Scientific EffectOptical element array generating point light sources: Lens

Implementation Method 2

at least one of the first optical element and the second optical element has a rotation angle about an optical axis thereof so as to perform compensate for distortion of the illumination region by the oblique illumination

Methodology Applied

Scientific EffectOptical element rotation:

Data Source

PatentUS10761316B2Illumination apparatus, optical apparatus, imprint apparatus, projection apparatus, and method of manufacturing article

Publication Date: 2020.09.01 CANON KK

AI summary

The present invention provides an illumination apparatus which performs oblique illumination, the apparatus including a first optical element formed with an array of a plurality of optical components each configured to generate a point light source, and a second optical element configured to receive light from the first optical element and form an illumination region, with a power thereof in one direction being different from a power thereof in a direction perpendicular to the one direction, wherein at least one of the first optical element and the second optical element has a rotation angle about an optical axis thereof so as to perform compensate for distortion of the illumination region by the oblique illumination.