Light Bulb Feedthrough Body for Multi-Wire Isolation

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Solution Overview

Problem

Conventional incandescent bulbs are limited in the number and size of wires that can be melted into the glass stem, making it difficult to accommodate the increased number of wires required by newer LED filament lamps.

Innovation Solution

A light bulb design featuring a glass stem with a multi-wire gas-tight feedthrough, where a feedthrough body made of ceramic or glass is fused into the stem, allowing multiple electrical conductors to be isolated and connected to the light engine, exceeding the limitations of traditional bulbs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional lead-in wires are melted into the glass stem at high temperatures, then the wires can be securely fixed in the stem, but the number of wires is limited to maximally four and isolation between wires cannot be maintained

Engineering Contradiction:
Improvewire fixation securityVSAvoidnumber of wires
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The invention divides the single glass stem into two separate components: a glass stem and a ceramic feedthrough body. The ceramic feedthrough body is segmented to contain multiple wire channels with insulation between them, allowing more than four wires to pass through while maintaining isolation. This segmentation resolves the contradiction by enabling increased wire quantity while preserving secure fixation through the ceramic material's ability to hold multiple isolated conductors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure combining glass (stem) and ceramic (feedthrough body) materials. The ceramic material provides high-temperature stability and electrical insulation properties that glass alone cannot achieve, enabling multiple wires to be fixed securely at high temperatures while maintaining electrical isolation. This composite approach resolves the contradiction between reliable fixation and increased wire capacity.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If more than two wires are required for LED filament lamps, then the light engine can receive sufficient power and signals, but the conventional glass stem cannot accommodate the increased number of wires

Engineering Contradiction:
Improvepower and signal capacityVSAvoidstem structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The ceramic feedthrough body acts as an intermediary component between the glass stem and the light engine, providing a dedicated structure for accommodating multiple power and signal wires. This intermediary element resolves the contradiction by handling the complex wiring requirements without complicating the glass stem structure itself, allowing the stem to remain relatively simple while the feedthrough body manages the multi-wire complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention transitions from a simple linear wire arrangement in the glass stem to a multi-dimensional structure where the ceramic feedthrough body provides vertical and radial wire routing. This dimensional change allows multiple wires to be organized in three-dimensional space within the feedthrough body, increasing power and signal capacity without proportionally increasing the overall device complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If wires are melted into the glass stem in the traditional way, then the wires can be fixed in the stem, but the wire size and material are restricted

Engineering Contradiction:
Improvewire fixation processVSAvoidwire material and size options
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The invention changes the material parameter of the feedthrough structure from glass to ceramic, which fundamentally alters the acceptable wire material and size parameters. Ceramic material can accommodate a broader range of wire materials and dimensions compared to glass, while still allowing high-temperature fixation processes. This parameter change resolves the contradiction by expanding wire options without sacrificing ease of manufacture through established ceramic firing processes.

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 design enables the accommodation of a larger number of wires, improving the reliability and safety of the light bulb by preventing electrical conductor contact and allowing for a wider range of electrical current conductors to be passed through the glass stem.

Implementation Method 1

a feedthrough body extending through the glass stem and being fixed by fusion in said tubular portion

Methodology Applied
Scientific EffectFusion: Melting

Implementation Method 2

the stem supporting the light engine and is fused by its flare to the light transmissive surface structure

Methodology Applied
Scientific EffectFusion: Melting

Data Source

PatentEP4158240B1A light bulb
Publication Date: 2025.02.12 SIGNIFY HOLDING BV
  • EP4158240B1 patent drawingFigure 1
  • EP4158240B1 patent drawingFigure 2
  • EP4158240B1 patent drawingFigure 3A~3C

AI summary

A light bulb (10) comprising a feedthrough body (26) for accommodating electrical conductors (24) through a glass stem (23) of the light bulb (10) is disclosed. The light bulb (10) comprises a light engine (21) arranged within a sealed light transmissive surface structure (22), a feedthrough body (26) sealed in and extending through the glass stem (23) supporting the light engine (21), a plurality of conductive wires (24) mutually electrically isolated from each other and extending through and gastightly sealed in the feedthrough body (26), the conductive wires (24) connecting the light engine (21) to at least one power and signal source.