Structured Diamond Tool FIB Nanomachining Grating Profile

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Solution Overview

Problem

Existing methods for manufacturing grayscale gratings, such as photolithographic processes, are inadequate for producing complex grating molds with fine features required for advanced optical pickup designs, as they lack the precision and efficiency to machine micrometer- to sub-micrometer-size features effectively.

Innovation Solution

A structured diamond tool with a predefined grayscale grating profile is created using high precision focused ion beam (FIB) nanomachining, allowing for the machining of complex grating profiles in a single pass, enabling the production of gratings or grating molds with features on the order of tens of nanometers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photolithographic processes are used to make grating molds, then binary gratings can be produced, but grayscale gratings with fine features cannot be produced with required precision

Engineering Contradiction:

Improvegrating feature precisionVSAvoidgrating profile complexity

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces photolithographic processes with focused ion beam (FIB) nanomachining to create grayscale grating molds. The FIB system uses a ion beam to directly write the grating profile onto the mold material, eliminating the limitations of photolithography for complex grayscale profiles while achieving the required sub-micrometer precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the manufacturing parameters by using FIB nanomachining with controlled ion beam current and scanning patterns to create varying material removal rates, thereby producing grayscale profiles with different depths and intensities that are impossible to achieve with binary photolithographic processes.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If single point diamond turning is used to machine gratings, then simple grating shapes can be produced, but complex grayscale profiles cannot be machined effectively

Engineering Contradiction:

Improvegrating manufacturing simplicityVSAvoidgrating profile accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by first creating a master mold with the complete grayscale grating profile using FIB nanomachining. This master mold is then used for press molding to mass-produce multiple gratings, combining the precision of FIB with the efficiency of mold-based manufacturing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary master mold that bridges the gap between FIB nanomachining and mass production. The FIB-created master mold serves as a template for press molding, allowing complex profiles to be replicated efficiently without requiring the FIB system to machine each grating individually.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If multiple passes are used to machine the grating profile with a single-point diamond tool, then the grating can be produced, but manufacturing time increases significantly

Engineering Contradiction:

Improvegrating production speedVSAvoidgrating profile accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the manufacturing process into two distinct stages: (1) FIB nanomachining of the master mold with the complete grayscale profile in a single pass, and (2) press molding replication for mass production. This segmentation allows the FIB system to focus on creating the precise master pattern while the press molding handles high-volume production.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses copying by creating a master mold with the exact grayscale grating profile using FIB, then using this master to press mold multiple copies of the grating. This allows the complex profile to be replicated with high precision across many units without repeating the slow FIB machining process for each grating.

Inventive Principle:

Principle #26Copying

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 approach significantly reduces manufacturing time and improves accuracy, enabling the production of complex grating profiles with high precision, suitable for advanced optical pickup designs, by using a diamond tool with features that can be machined in a single pass or multiple periods with enhanced resolution.

Implementation Method 1

a high precision focused ion beam (FIB) nanomachining tool can machine features on the order of tens of nanometers

Methodology Applied

Scientific EffectFocused Ion Beam: Ion Beam

Data Source

PatentUS8709219B2Structured diamond tool made by focused ion beam nanomachining

Publication Date: 2014.04.29 PANASONIC HOLDINGS CORP

AI summary

A structured diamond tool having a predefined grayscale grating profile shape allows a corresponding grayscale grating profile to be machined into a work piece with a single pass with high accuracy. Manufacture of grayscale gratings using this technique saves time compared to the situation where the profile is machined by a single-point diamond tool with multiple passes. Also, more time-saving is realized if more than one period is machined in the diamond tool. Such a tool can be manufactured using a high precision focused ion beam (FIB), which is a true nanomachining tool that can machine features on the order of tens of nanometers. The diamond tool made by FIB therefore has extremely fine resolution and features required by the grayscale grating.