Monolithic Optical Transformer With Vertically Stacked LED-PD Coupling

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing opto-couplers face inefficiencies due to optical losses associated with transitions between dielectric media with different refractive indices, limiting their quantum efficiency and power transfer capabilities.

Innovation Solution

A monolithic optical device is developed, integrating a light-emitting diode (LED) and a photodiode (PD) in a single semiconductor die, with a semi-insulating layer or tunnel junction separating them, allowing for vertical stacking and reduced optical losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If separate LED and photodiode devices are used in conventional opto-couplers, then device functionality is achieved, but optical losses occur due to transitions between dielectric media with different refractive indices

Engineering Contradiction:

Improveoptical lossesVSAvoiddevice structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent merges the LED and photodiode into a single monolithic semiconductor device, integrating both light emission and detection functions within the same die. This eliminates the optical transitions between separate dielectric media that cause energy losses, directly resolving the contradiction between reducing optical losses and maintaining device functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from a lateral arrangement of separate LED and photodiode devices to a vertical stacking configuration within a single monolithic structure. This dimensional change enables direct optical coupling between the LED active region and photodiode active region, eliminating refraction losses at interfaces while maintaining electrical isolation through the semi-insulating layer.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of energy

If a monolithic structure is used to eliminate optical losses, then quantum efficiency is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvequantum efficiencyVSAvoidmanufacturing process

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The monolithic semiconductor structure is segmented into distinct functional regions including the LED active region, semi-insulating layer, and photodiode active region. This segmentation allows each region to be optimized for its specific function while maintaining a unified monolithic structure that can be manufactured using standard semiconductor fabrication processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A semi-insulating layer is introduced as an intermediary between the LED and photodiode regions. This layer provides electrical isolation to prevent carrier leakage while maintaining optical transparency to allow efficient light transmission from the LED to the photodiode, thus improving quantum efficiency without compromising manufacturability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If vertical stacking of LED and photodiode junctions is implemented, then optical coupling efficiency is enhanced, but device fabrication difficulty increases

Engineering Contradiction:

Improveoptical coupling efficiencyVSAvoidfabrication precision

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent implements local quality by creating distinct regions with specific properties within the monolithic structure: the LED active region is optimized for light emission, the semi-insulating layer provides electrical isolation with optical transparency, and the photodiode active region is optimized for light detection. This localized optimization enables efficient vertical optical coupling while maintaining manufacturability through standard fabrication techniques.

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 the overall quantum efficiency of the opto-coupler, enabling the transfer of larger power quantities and broader functionality by minimizing internal optical losses.

Implementation Method 1

a light-emitting diode (LED) junction

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a photo diode (PD) junction

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS20250040288A1Monolithic Optical Transformer

Publication Date: 2025.01.30 LUMILEDS SINGAPORE PTE LTD

AI summary

Provided are optical transformer devices having a high power efficiency. The device architecture provides uniform current spreading to minimize efficiency droop. The quantum well designs are optimized for both light-emitting diode (LED) and photo diode (PD) operation. A low-loss optical cavity allows efficient transfer of light from the LED junction to the PD junction. The architecture provides a low-loss voltage up- and down-conversion and provides compatibility with production-grade epitaxial growth and wafer fabrication processes.