Twisted Light Guide for LED Filament Lamp Appearance
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Solution Overview
Problem
Current LED filament lamps are expensive, have an undesirable yellowish appearance, and lack color or color temperature tunability, making them costly to manufacture and unsuitable for producing incandescent lamp alternatives with a clearer white light.
Innovation Solution
A light emitting device featuring an elongated twisted light guide with a central longitudinal axis, where light is coupled in via total internal reflection and emitted through elongated out-coupling elements, allowing for efficient light transmission and color tunability, and comprising features like light scattering, refracting, and diffracting elements for improved light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If LED filaments are placed in glass bulbs to create retrofit lamps, then the appearance resembles incandescent bulbs and is highly decorative, but the manufacturing cost becomes expensive
Solution Approach 1:
The patent creates a visual copy of the incandescent filament appearance using LED technology combined with a light guide structure. The light guide with twisted configuration and surface features replicates the aesthetic of traditional filaments without using actual filament materials, thereby achieving the desired appearance while reducing manufacturing complexity and cost.
2Device complexity
If current LED filament lamp designs are used, then the structure is relatively simple, but the light appearance becomes yellow or yellowish and lacks color tunability
Solution Approach 1:
The patent applies local quality by incorporating specific surface features (such as prisms, diffusers, or textured patterns) at particular locations on the light guide structure. These localized optical features selectively modify light extraction and distribution to achieve clearer white appearance and enable color tunability without complicating the overall device structure.
3Use of energy by moving object
If traditional incandescent lamp infrastructure is replaced with LED filaments, then energy efficiency improves, but the manufacturing cost and assembly complexity increase
Solution Approach 1:
The light guide structure serves multiple functions simultaneously: it guides light from the LED source, provides structural support, creates the filament appearance, enables color distribution, and facilitates heat management. This multi-functionality reduces the need for separate components, simplifying manufacturing and assembly while maintaining energy efficiency benefits of LED technology.
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 results in a cost-effective, brighter, and more aesthetically pleasing light output with clear white appearance and color tunability, simplifying assembly and manufacturing while providing a regular spiraling light pattern.
Implementation Method 1
the elongated light guide is configured to guide at least a portion of the light source light which is coupled into the light guide at the light in-coupling element via total internal reflection to the light out-coupling element
Data Source
Figure 1
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AI summary
A light emitting device (1) comprising at least one LED light source (6, 61, 62) adapted for, in operation, emitting light source light, and an elongated light guide (2) comprising a height direction (H), a width direction (W), a depth direction (D), a longitudinal axis (L) extending in the height direction (H), a first major surface (31) and a second major surface (32) arranged extending opposite to the first major surface in the depth direction (D), a first minor surface (41) and a second minor surface (42) arranged extending opposite to the first minor surface in the width direction (W), and a first end (51) and a second end (52) arranged extending opposite to the first end in the height direction (H), where the elongated light guide (2) further comprises at least one light in-coupling element (7, 71, 72) configured to couple the light source light into the elongated light guide and at least one light out-coupling element (81, 82) configured to couple the light source light out of the elongated light guide, where the elongated light guide (2) is twisted around the longitudinal axis (L), and where the at least one light out-coupling element (81, 82) is elongated.