Glass Waveguide Assemblies for OE-PCB Fabrication

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Solution Overview

Problem

The fabrication of optical-electrical printed circuit boards (OE-PCBs) is complex and costly due to the incompatibility of glass substrates with standard PCB fabrication and assembly techniques, leading to manufacturing inefficiencies, low yield, and high costs.

Innovation Solution

The use of glass waveguide assemblies, where optical, mechanical, and electrical features are added to a glass sheet prior to PCB fabrication, making them compatible with standard PCB processes such as lamination, drilling, and chemical processing, and allowing for roll-to-roll processes with flexible glass substrates of thickness below 300 microns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If glass substrates are used for OE-PCB fabrication, then optical waveguide functionality is achieved, but compatibility with standard PCB fabrication techniques is lost

Engineering Contradiction:
Improveoptical waveguide functionalityVSAvoidcompatibility with standard PCB fabrication
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The glass substrate is divided into multiple segments or layers, with waveguides formed in specific regions while leaving other areas compatible with standard PCB processes. This segmentation allows different portions of the substrate to serve different functions - optical guiding in some areas and standard PCB fabrication in others.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The glass substrate is modified locally to create waveguide regions with specific optical properties (different refractive index, density) while maintaining the bulk glass properties compatible with standard PCB fabrication. The ion exchange process creates localized changes in specific areas rather than altering the entire substrate.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If glass substrates are used for OE-PCB fabrication, then optical waveguide functionality is achieved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveoptical waveguide functionalityVSAvoidfabrication process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines glass substrate processing with standard PCB fabrication processes into a unified manufacturing flow. By making the glass substrate compatible with existing PCB equipment and processes (lamination, drilling, milling, chemical processing), the complex separate glass fabrication process is merged with routine PCB manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Waveguide structures are formed in the glass substrate before the standard PCB fabrication process begins. This preliminary action allows the optical structures to be pre-defined while the glass substrate is then processed through standard PCB steps, avoiding the need for complex post-PCB fabrication glass processing.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If thin flexible glass substrates are used, then compatibility with roll-to-roll processes is achieved, but mechanical strength and handling robustness decrease

Engineering Contradiction:
Improveroll-to-roll process compatibilityVSAvoidmechanical strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent employs thin flexible glass substrates (thickness below 300 microns) that can be processed using roll-to-roll manufacturing techniques. The flexibility and thinness enable high-speed continuous processing while the glass material maintains sufficient mechanical integrity for handling.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The glass substrate is combined with other materials (such as polymer layers, metal traces, or protective coatings) to create a composite structure that enhances mechanical strength while maintaining the flexibility and thinness required for roll-to-roll processing. The composite structure compensates for the reduced strength of thin glass.

Inventive Principle:
Principle #40Composite materials

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 simplifies the OE-PCB fabrication process, increases throughput, and enables the use of established PCB processes, reducing costs and improving compatibility with standard handling and storage routines.

Implementation Method 1

a glass substrate having a body with a front-end section having a front end, a back-end section having a back end, a top surface, and a bottom surface. At least one glass optical waveguide is formed in the body of the glass substrate and runs generally from the front-end section to the back-end section

Methodology Applied
Scientific EffectOptical waveguide transmission: Waveguide (optics)

Data Source

PatentEP3577501B1Glass waveguide assemblies for oe-pcbs and methods of forming oe-pcbs
Publication Date: 2023.08.23 CORNING OPTICAL COMMUNICATIONS LLC

AI summary

The glass waveguide assembly includes a substrate with glass optical waveguides formed in the body of the glass substrate without adding or removing any glass from the substrate body. The glass optical waveguides run generally from a front-end section to a back-end section. A protective coating is formed over at least a portion of the top surface of the glass substrate where the glass optical waveguides reside. Optical connectors are formed at or adjacent the back end at corresponding connector regions. Each connector includes an end portion of at least one of the glass optical waveguides. In some configurations, the glass waveguide assembly includes a bend section that facilitates forming an optical interconnection in a photonic system between an optical-electrical printed circuit board and photonic integrated circuit.