Holographic Grating Exposure Light Path Using Compensating Mirror

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Solution Overview

Problem

The existing methods for manufacturing holographic gratings face challenges due to the close distance between exposure light sources, leading to light beam blocking and the inability to manufacture wide-spectrum gratings, which affects imaging quality and manufacturing requirements.

Innovation Solution

An exposure method that adjusts the positions of the exposure light sources using a compensating mirror, simulating initial and new light paths to ensure imaging quality parameters meet specific thresholds, thereby increasing the distance between light sources without compromising grating quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the distance between exposure light sources is reduced to meet manufacturing requirements for wide-spectrum gratings, then the grating line density can be reduced, but light beam blocking occurs and imaging quality deteriorates

Engineering Contradiction:

Improvegrating line densityVSAvoidlight beam blocking

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

A compensating mirror is introduced as an intermediary element in the exposure light path. This mirror redirects the light beams from the exposure light sources, effectively increasing the distance between light sources and preventing light beam blocking while maintaining the required grating line density for wide-spectrum gratings

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The compensating mirror changes the spatial dimension of the light path by introducing a reflection angle. This allows the light beams to travel a longer effective distance between sources without requiring physical separation of the light sources themselves, thus avoiding blocking while maintaining imaging quality

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If a specially manufactured micro-objective is used to reduce spatial filter size and avoid blocking, then blocking is prevented, but the performance of the micro-objective is reduced and imaging quality deteriorates

Engineering Contradiction:

Improvelight beam blockingVSAvoidimaging quality

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The compensating mirror serves as an intermediary that prevents light beam blocking without requiring modification of the micro-objective. This preserves the original performance and imaging quality of the micro-objective while still solving the blocking problem

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The blocking problem is extracted from the spatial filter assembly and addressed separately by the compensating mirror in the light path. This allows the spatial filter and micro-objective to maintain their original design and performance without compromise

Inventive Principle:

Principle #2Taking out (Extraction)

3Object-affected harmful factors

If the micro-objective and pin hole are separated and structured respectively, then blocking is avoided, but the adjustment difficulty is greatly improved

Engineering Contradiction:

Improvelight beam blockingVSAvoidadjustment difficulty

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The compensating mirror provides a centralized solution for preventing light beam blocking that does not require separating the micro-objective and pin hole. This maintains the integrated structure and simplifies adjustment procedures while still avoiding blocking

Inventive Principle:

Principle #24Intermediary (Mediator)

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 method effectively enlarges the distance between exposure light sources, preventing light beam blocking while maintaining the imaging quality and manufacturing requirements of holographic gratings, allowing for the production of wide-spectrum gratings.

Implementation Method 1

two coherent light beams, and interference exposure is performed on a grating substrate

Methodology Applied

Scientific EffectInterference: Interference

Implementation Method 2

setting a compensating mirror in the initial light path; adjusting positions of the exposure light sources to new positions according to a position of the compensating mirror

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS10146179B2Exposure method of holographic grating and exposure light path

Publication Date: 2018.12.04 TSINGHUA SHENZHEN INTERNATIONAL GRADUATE SCHOOL

AI summary

The invention provides an exposure method of a holographic grating and an exposure light path. The exposure method includes: (1) determining initial positions (C, D) of the two exposure light sources (S1, S2); (2) calculating imaging quality parameters of the grating; (3) setting a compensating mirror (A1) in the initial light path; (4) adjusting a position of the exposure light source (S1) to a new position (D1) according to a position of the compensating mirror (A1); (5) calculating imaging quality parameters of the grating; (6) judging whether the imaging quality parameters in the step (5) and the imaging quality parameters in the step (2) are equal, and if yes, using the new position (D1) as a final position of the exposure light source (S1). The exposure method and exposure light path may effectively solve a problem of a much too close distance between exposure light sources.