Surface-Emitting Laser Electrode Layout for Current Crowding

Solution Overview

Problem

Conventional surface emitting laser devices face issues with current crowding at the aperture edge, leading to reduced luminous intensity output, increased threshold current, and optical problems such as beam divergence due to high current operation, which affect electrical and optical characteristics.

Innovation Solution

The surface emitting laser device incorporates a transparent electrode layer with a specific contact area configuration and a metal electrode layer, where the transparent electrode layer directly contacts the second reflective layer to improve ohmic characteristics and current injection efficiency, while the metal electrode layer maintains or improves voltage efficiency, thereby addressing current crowding and beam divergence issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high current is applied to increase light output, then luminous intensity increases, but current crowding occurs at the aperture edge reducing current injection efficiency

Engineering Contradiction:

Improveluminous intensityVSAvoidcurrent injection efficiency

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating different contact area configurations for the transparent electrode layer at different locations. Specifically, the contact area between the transparent electrode layer and the second reflective layer is designed to be larger at the aperture edge region compared to the center region, which locally modifies the current distribution characteristics to prevent current crowding while maintaining overall high current injection efficiency

Inventive Principle:

Principle #3Local quality

2Power

If high current is applied to increase light output, then luminous intensity increases, but threshold current increases

Engineering Contradiction:

Improveluminous intensityVSAvoidthreshold current

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent employs parameter changes by modifying the contact area configuration parameter of the transparent electrode layer. By adjusting the contact area between the transparent electrode layer and the second reflective layer, particularly making it larger at the aperture edge, the electrical characteristics are optimized to reduce threshold current while enabling high luminous intensity operation

Inventive Principle:

Principle #35Parameter changes

3Power

If high current is applied to increase light output, then luminous intensity increases, but beam divergence angle increases

Engineering Contradiction:

Improveluminous intensityVSAvoidbeam divergence

Core Design Contradiction:

PowerVSIllumination intensity

Solution Approach 1:

The patent applies local quality by creating different contact area configurations for the transparent electrode layer at different locations. Specifically, the contact area between the transparent electrode layer and the second reflective layer is designed to be larger at the aperture edge region compared to the center region, which locally modifies the current distribution characteristics to prevent current crowding while maintaining overall high current injection efficiency

Inventive Principle:

Principle #3Local quality

4Device complexity

If conventional electrode configuration is used, then device structure is simple, but ohmic characteristics deteriorate and resistance increases

Engineering Contradiction:

Improveelectrode structureVSAvoidohmic characteristics

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by creating different contact area configurations for the transparent electrode layer at different locations. Specifically, the contact area between the transparent electrode layer and the second reflective layer is designed to be larger at the aperture edge region compared to the center region, which locally modifies the current distribution characteristics to prevent current crowding while maintaining overall high current injection efficiency

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 configuration enhances electrical and optical characteristics by ensuring uniform radiance intensity between the aperture edge and center, preventing damage to the aperture and reducing beam divergence, resulting in improved power conversion efficiency and light emission distribution.

Implementation Method 1

the transparent electrode layer directly contacts the second reflective layer to improve ohmic characteristics

Methodology Applied

Scientific EffectOhmic contact: Conduction (electrical)

Implementation Method 2

an active layer disposed on the first reflective layer

Methodology Applied

Scientific EffectLight emission: Electroluminescence

Implementation Method 3

a first reflective layer disposed on the substrate... and a second reflective layer disposed on the active layer

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS12080991B2Surface emitting laser device and light emitting device including the same

Publication Date: 2024.09.03 SUZHOU LEKIN SEMICON CO LTD

AI summary

An embodiment relates to a surface emitting laser device and a light emitting device including the same. The surface emitting laser device according to an embodiment may comprise: a substrate; a first reflective layer arranged on the substrate; an active layer arranged on the first reflective layer; an aperture layer arranged on the active layer and comprising an opening; a second reflective layer arranged on the active layer; a transparent electrode layer arranged on the second reflective layer; and a metal electrode layer arranged on the transparent electrode layer. The transparent electrode layer may comprise a first area perpendicularly overlapping the opening and multiple second areas extending from the first area. The multiple second areas may be arranged outside the opening along the circumferential direction of the opening and spaced apart from each other. The multiple second areas may be arranged and spaced apart from each other so as to correspond to the circumference of the opening. The metal electrode layer may electrically contact the second reflective layer between the multiple second areas.