Variable Depth Optical Grating via Ribbon Ion Beam

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Solution Overview

Problem

Existing augmented and virtual reality devices face challenges with optical grating height variations that lead to discontinuous changes, increasing processing complexity and resulting in blockiness issues due to multiple etched regions with different grating heights.

Innovation Solution

The development of an optical grating component with angled structures inclined at a non-zero angle, allowing for a smooth variation in grating height along a direction parallel to the substrate, achieved through selective area processing using a ribbon ion beam, which generates a variable depth in a continuous fashion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple different regions with different grating heights are formed using different etches, then the optical component can provide different grating heights in different regions, but the processing complexity increases and blockiness appears over the lens

Engineering Contradiction:

Improvegrating height variationVSAvoidprocessing complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the etching parameters (etch time, power, gas flow rates) dynamically during a single continuous etching process to achieve different grating heights in different regions. This allows precise control of grating depth by adjusting etch power and duration locally while maintaining process continuity, thereby achieving manufacturing precision without increasing overall processing complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent segments the etching process into different zones along the scan direction, where each zone has tailored etching parameters. This segmentation is achieved through spatially selective parameter adjustment during continuous scanning, allowing different grating heights to be created in different regions without requiring separate etching steps for each region

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

Engineering Contradiction:

Improvegrating height variationVSAvoidgrating height continuity

Core Design Contradiction:

Manufacturing precisionVSShape

Solution Approach 1:

The patent employs a single continuous scanning etching process that continuously adjusts parameters along the scan direction. This continuous action ensures smooth transitions in grating depth between regions, eliminating the discontinuities and blockiness that would result from separate etching steps. The useful action of etching continues uninterrupted while parameters are modulated to achieve desired height variations

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent introduces dynamic parameter adjustment during the etching process, where etch power, scan speed, or gas flow rates are varied continuously along the scan direction. This dynamic control allows the grating depth to change smoothly from one region to another, creating a continuous height profile rather than discrete steps, thereby eliminating blockiness

Inventive Principle:

Principle #15Dynamics

3Device complexity

If a single continuous etching process with parameter modulation is used, then processing complexity is reduced and smooth grating transitions are achieved, but the capability to create multiple grating height regions is limited

Engineering Contradiction:

Improveprocessing complexityVSAvoidgrating height region capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal etching process that can generate multiple grating height regions through parameter modulation. By programming different parameter profiles along the scan direction, the same continuous etching apparatus can produce various grating depth patterns, making the process adaptable to different optical design requirements without requiring additional specialized equipment or process steps

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 improves the performance of augmented reality glasses by providing a better distribution of light and a more seamless augmented reality image, reducing processing complexity and eliminating blockiness issues.

Implementation Method 1

etching the grating layer using a ribbon ion beam, wherein the substrate is scanned along a scan direction with respect to the ribbon ion beam using a selective area processing recipe

Methodology Applied

Scientific EffectSputtering: Sputtering

Data Source

PatentUS11404278B2Optical component having variable depth gratings and method of formation

Publication Date: 2022.08.02 VARIAN SEMICON EQUIP ASSC INC

AI summary

An optical grating component may include a substrate, and an optical grating, the optical grating being disposed on the substrate. The optical grating may include a plurality of angled structures, disposed at a non-zero angle of inclination with respect to a perpendicular to a plane of the substrate, wherein the plurality of angled structures are arranged to define a variable depth along a first direction, the first direction being parallel to the plane of the substrate.