VCSEL Array Block Separation for Uniform High-Density Emission

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Solution Overview

Problem

Existing light-emitting element arrays face issues with non-uniformity in light emission due to the arrangement position of vertical cavity surface emitting lasers (VCSELs), and there is a need for a method to suppress influences on the array of light-emitting elements while maintaining high emission efficiency and density.

Innovation Solution

A light-emitting element array is designed with constriction grooves around each element to form a current constriction layer, and a block separation portion with a curved shape is introduced to separate light-emitting elements into blocks, ensuring electrical insulation and uniform emission control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If light-emitting elements are arranged in high density, then productivity and emission density are improved, but non-uniformity in light emission occurs due to arrangement position

Engineering Contradiction:
Improveemission densityVSAvoidlight emission uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by forming current constriction layers with different oxidation depths at different locations. Specifically, the oxidation depth is controlled to be greater in block separation portions than in light-emitting element portions, creating locally differentiated electrical insulation properties that address the non-uniformity issue while maintaining high density arrangement

Inventive Principle:
Principle #3Local quality

2Reliability

If block separation portion is introduced to suppress influence on light-emitting elements, then reliability is improved, but device complexity increases due to additional curved groove structure

Engineering Contradiction:
Improveelectrical insulationVSAvoidblock separation structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the light-emitting element array into multiple blocks using block separation portions. This segmentation approach isolates different functional regions, allowing independent optimization of current constriction in light-emitting areas while ensuring adequate electrical insulation in separation areas, thereby improving reliability without excessive complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The block separation portion is designed with a curved shape including at least one inflection point, which allows the groove to smoothly navigate around light-emitting elements. This curved geometry provides effective electrical insulation while maintaining a compact layout and avoiding excessive structural complexity

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Loss of energy

If constriction grooves are formed around each light-emitting element, then emission efficiency is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveemission efficiencyVSAvoidconstriction groove formation
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent employs parameter changes by controlling the oxidation depth as a variable parameter. The oxidation depth is adjusted to be greater in block separation portions than in light-emitting element portions, allowing optimization of both emission efficiency and electrical insulation through a single manufacturable process with controlled parameters

Inventive Principle:
Principle #35Parameter changes

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 configuration effectively suppresses non-uniformity and influences on the light-emitting elements, allowing for efficient light emission control and increased density by restricting current flow and preventing oxidation from the block separation groove, resulting in improved power consumption and emission efficiency.

Implementation Method 1

a current constriction layer is formed by oxidizing a light-emitting layer from inside the constriction groove

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentEP4125167B1Light-emitting element array, optical device, optical measurement device, and method for manufacturing light-emitting element array
Publication Date: 2024.07.24 FUJIFILM BUSINESS INNOVATION CORP
  • EP4125167B1 patent drawingFigure 1
  • EP4125167B1 patent drawingFigure 2
  • EP4125167B1 patent drawingFigure 3

AI summary

A light-emitting element array includes a substrate, plural light-emitting elements arranged on the substrate, plural constriction grooves being provided in a periphery of each of the plural light-emitting elements and forming a current constriction layer that constricts a current flowing through a light-emitting layer by oxidizing the light-emitting layer, and a block separation portion that is provided in a curved shape so as to include at least one inflection point at which a sign of curvature changes along each of positions where the plural light-emitting elements are arranged, and separates the plural light-emitting elements into plural blocks.