Laser-Modified Light-Absorbing Substrate Manufacturing

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Solution Overview

Problem

Existing methods for manufacturing light-absorbing substrates require significant time and effort to form desirable patterns of depressions and projections, limiting efficiency and precision.

Innovation Solution

The method employs laser irradiation to create modified regions on a substrate, which are then etched to form depressions and projections, allowing control of position and form through laser and etching conditions, with anisotropic and isotropic etching steps to stabilize and smooth the surface features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a masking pattern is formed on the substrate surface to control depression positions and forms, then manufacturing precision is improved, but manufacturing complexity and time consumption increase

Engineering Contradiction:
Improveposition and form control of depressionsVSAvoidmasking pattern formation process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts the masking function from the physical mask and transfers it to the laser-modified regions on the substrate. The laser creates modified regions that directly define where depressions will form, eliminating the need for separate masking layers and their associated alignment and formation processes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical masking system with a laser-based modification system. Instead of using physical masks that require mechanical alignment and handling, the invention uses laser irradiation to create modified regions that serve as etching starting points, substituting a mechanical process with an optical/thermal one.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If a masking pattern is formed on the substrate surface, then depression pattern control is improved, but manufacturing time and effort increase

Engineering Contradiction:
Improvedepression pattern controlVSAvoidmasking pattern formation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary laser modification of the substrate surface to create modified regions at the desired depression locations before the etching process. This preliminary action defines the exact positions where depressions will form, eliminating the need for time-consuming mask application and alignment steps that would otherwise be required.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses the laser-modified regions as direct templates or copies of the desired depression pattern. The modified regions themselves become the pattern definition, eliminating the need for separate masking layers that would need to be applied, aligned, and processed to create the same pattern.

Inventive Principle:
Principle #26Copying

3Manufacturing precision

If anisotropic etching is performed to maintain uniform depression forms, then manufacturing precision is improved, but additional process steps are required

Engineering Contradiction:
Improvedepression form uniformityVSAvoidetching process steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by using anisotropic etching that exploits the crystallographic orientation of the substrate. The etching process is designed to proceed at different rates in different directions based on the underlying crystal structure, naturally producing uniform depression forms without requiring additional masking or alignment steps.

Inventive Principle:
Principle #3Local quality

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 enables the efficient and precise manufacturing of light-absorbing substrates with desirable surface patterns and the creation of molds with complementary features, enhancing production efficiency and pattern control.

Implementation Method 1

a substrate is irradiated with laser light so that at least one of modified regions formed within the substrate and a fracture generated from each of the modified regions reaches the surface of the substrate

Methodology Applied
Scientific EffectLaser irradiation: Laser

Implementation Method 2

etching selectively advances from each of the modified regions, so as to form a plurality of depressions on the surface of the substrate

Methodology Applied
Scientific EffectEtching:

Implementation Method 3

In the second step, anisotropic etching may be performed as the etching. This can inhibit a plurality of depressions produced on the surface of the substrate from fluctuating their forms among them.

Methodology Applied
Scientific EffectAnisotropic etching: Anisotropy

Implementation Method 4

In the second step, isotropic etching may be performed as the etching after the anisotropic etching. This can smoothen the inner faces of a plurality of depressions formed on the surface of the substrate.

Methodology Applied
Scientific EffectIsotropic etching:

Data Source

PatentEP2600411B1Method for manufacturing light-absorbing substrate and method for manufacturing die for manufacturing light-absorbing substrate
Publication Date: 2019.08.21 HAMAMATSU PHOTONICS KK
  • EP2600411B1 patent drawingFigure 1
  • EP2600411B1 patent drawingFigure 2
  • EP2600411B1 patent drawingFigure 3

AI summary

A method for manufacturing a light-absorbing substrate having a surface with depressions and projections comprises a first step of irradiating a substrate with a laser light so as to form a plurality of modified regions arranged two-dimensionally along a surface of the substrate within the substrate and cause at least one of each modified region and a fracture generated from the modified region to reach the surface of the substrate and a second step of etching the surface of the substrate after the first step so as to form depressions and projections on the surface of the substrate.