LED Filament Housing Layout for Split Uplight and Downlight

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Solution Overview

Problem

Existing LED filament applications are limited to light bulbs and do not leverage their omnidirectional light emission for diverse lighting needs, particularly in suspended luminaires requiring both downlight and uplight with controlled glare.

Innovation Solution

A lighting device utilizing LED filaments with a housing design that allows omnidirectional light to be split into two opposite directions, using reflective surfaces and compartmentalized tracks to minimize light absorption and enable independent control of light flux and color temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If LED filaments are used in conventional light bulbs only, then the application scope is limited, but the omnidirectional light emission capability is wasted

Engineering Contradiction:
Improveapplication scopeVSAvoidwasted light emission capability
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent applies LED filaments in multiple lighting applications beyond conventional bulbs, including suspended luminaires, surface-mounted luminaires, and recessed luminaires. The same omnidirectional LED filament light source is adapted to fulfill different lighting functions and requirements across various application scenarios, maximizing the utility of the omnidirectional light emission capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent segments the omnidirectional light flux from LED filaments into different directional components using reflective surfaces and optical elements. The light is divided into upward-directed flux for ceiling illumination and downward-directed flux for task lighting, allowing the single omnidirectional source to serve multiple lighting zones simultaneously.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If suspended luminaire requires both downlight and uplight, then lighting functionality is improved, but device complexity increases

Engineering Contradiction:
Improvelighting functionalityVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses a single omnidirectional LED filament light source to perform multiple lighting functions simultaneously - providing both upward illumination for ceiling wash and downward illumination for task lighting. This eliminates the need for separate light sources for uplight and downlight, reducing overall system complexity while maintaining dual functionality.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces reflective surfaces and optical elements as intermediaries to redirect and distribute the omnidirectional light flux from the LED filament. These intermediaries split the light into upward and downward directions, enabling dual lighting functionality without requiring additional light sources or complex optical systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If tracks are placed inside inner cavity, then electrical connection is simplified, but light absorption increases

Engineering Contradiction:
Improveelectrical connection simplicityVSAvoidlight absorption
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent extracts the electrical tracks from the inner optical cavity and relocates them to the outer housing structure. This separation removes the light-absorbing electrical components from the light path, allowing the LED filament light to illuminate the cavity walls and exit through windows without being absorbed by tracks, wires, or connectors inside the cavity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates electrical connections through the cavity walls using contact points or conductive elements that extend through the housing walls. This allows electrical power to be delivered to the LED filaments without requiring physical tracks inside the optical cavity, maintaining electrical connectivity while eliminating light absorption by internal wiring.

Inventive Principle:
Principle #26Copying

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

Achieves high light efficiency and flexibility in lighting direction and color temperature, suitable for suspended luminaires with controlled downlight and uplight, enhancing aesthetic and functional properties.

Implementation Method 1

The inner cavity of the housing has a first window in a first direction and a second window in a second direction, opposite to the first direction... the cavity surface is at least partly reflective... By the reflective property of the inner cavity surface, a majority of the emitted light can be directed to exit the lighting device through the windows.

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4671601A1LED filament lighting device
Publication Date: 2025.12.31 SIGNIFY HOLDING BV
  • EP4671601A1 patent drawingFigure 1~2
  • EP4671601A1 patent drawingFigure 3A
  • EP4671601A1 patent drawingFigure 3B

AI summary

A lighting device (10) configured to, in operation, provide lighting device light. The lighting device comprising a housing (20) and a light source (50). The housing comprises a cavity surface (23) defining an inner cavity (24) of the housing. The inner cavity has a first window (21) in a first direction (D1) and a second window (22) in a second direction (D2), opposite to the first direction. The first window has a first area (A1), and the second window has a second area (A2). The light source comprises a plurality of light emitting diode, LED, filaments (52) configured to, in operation, provide LED filament light within the inner cavity. The LED filaments are electrically connected between first and second tracks. The LED filament light leaves the housing through either the first window or the second window. A luminaire comprising a lighting device is also disclosed.