LED Filament Lighting Device with Light Guide for Glare Reduction
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Solution Overview
Problem
Existing LED-based lighting solutions that mimic incandescent bulbs suffer from excessive glare when increasing the intensity of the LED-filament, as they have a small light emitting surface, leading to discomfort and unsatisfactory aesthetics.
Innovation Solution
A lighting device comprising an LED-filament and a light guide, where the LED-filament is external to the light guide, which increases the light emitting surface through total internal reflection, reducing brightness and glare, while maintaining the aesthetic appeal of an incandescent bulb.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the intensity of the LED-filament is increased to increase lumen output, then the brightness increases, but the glare increases excessively
Solution Approach 1:
The patent introduces a light guide component that redirects and redistributes light in additional spatial dimensions. The light guide has multiple light out-coupling portions positioned at different locations and angles, transforming the concentrated light output into a distributed three-dimensional light pattern, thereby increasing lumen output without concentrating glare in a single direction
Solution Approach 2:
The light guide acts as an intermediary component between the LED-filament and the envelope. It receives light from the LED-filament through light in-coupling portions, processes the light through total internal reflection, and redistributes it through multiple out-coupling portions, thereby mediating between the light source and the environment to reduce glare while maintaining brightness
2Object-affected harmful factors
If the light emitting surface is increased to reduce glare, then the brightness distribution improves, but the device complexity increases
Solution Approach 1:
The light guide is positioned inside the envelope and surrounds the LED-filament in a nested configuration. The light guide's elongated body is contained within the envelope volume, creating a compact nested structure that increases the effective light emitting surface without proportionally increasing the overall device volume or structural complexity
Solution Approach 2:
The light guide serves multiple functions simultaneously: it acts as a light redistribution medium, provides structural support for the LED-filament, defines the internal geometry of the luminaire, and contributes to the overall aesthetic appearance. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity
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
The solution effectively reduces glare and enhances the decorative lighting effect by distributing light in a broader spatial pattern, improving the overall aesthetic and comfort of the lighting experience.
Implementation Method 1
The at least one light guide guides the light which is coupled into the at least one light guide at the at least one light in-coupling portion via total internal reflection to the plurality of light out-coupling portions
Data Source
AI summary
A lighting device (100) for use in a luminaire (200) comprising: —a base (101) having a longitudinal axis (LA) and comprising an electrical connector (102) for connecting the lighting device (100) to a luminaire socket (201) of the luminaire (200), —at least one LED-filament (103) comprising a substrate (104) having an elongated body and a plurality of light sources (105) mechanically coupled to the substrate (104), the plurality of light sources (105) configured for emitting light (106) in a first spatial light distribution, —at least one light guide (107) having an elongated body, comprising at least one light in-coupling portion (108) at at least on the external periphery of the at least one light guide (107) for coupling light (106) into the at least one light guide (107), a plurality of light out-coupling portions (109) for coupling light (106) out of the at least one light guide (107) in a second spatial light distribution, —an at least in part light-transmissive envelope (110) at least partly encapsulating said at least one LED-filament (103) and said at least one light guide (107), —wherein the at least one light guide (107) is arranged for guiding the light (106) coupled into the at least one light guide (107) at the at least one light in-coupling portion (108) via total internal reflection (111) to the plurality of light out-coupling portions (109), —wherein the at least one LED-filament (103) is external to the at least one light guide (107).