Side Emitting Device Hybrid Top Reflector
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Solution Overview
Problem
Existing side-emitting light emitting devices are thick due to the configuration of remote reflectors and scattering materials, which increases the device thickness and allows light to escape through the top surface, making them unsuitable for thin applications like handheld display devices.
Innovation Solution
A side-emitting light emitting device with an essentially opaque reflector comprising non-parallel oriented reflective flakes in a transmissive carrier, which scatters and reflects light without allowing it to exit through the top surface, allowing all light to exit through lateral openings, and optionally includes a wavelength converting material for color adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If remote reflectors and scattering materials are used to enhance side emission, then light extraction efficiency is improved, but device thickness increases
Solution Approach 1:
The patent combines the reflector and scattering material into a single integrated layer. The reflector layer contains both reflective particles (for high reflectivity) and scattering particles (for angular redistribution), eliminating the need for separate remote reflector and scattering material layers. This merging reduces device thickness while maintaining enhanced light extraction efficiency.
Solution Approach 2:
The reflector layer uses composite materials containing both reflective particles (such as metal flakes or dielectric particles with high refractive index) and scattering particles (such as TiO2 or SiO2 particles). This composite structure provides both high reflectivity and strong scattering effects in a single thin layer, resolving the contradiction between light extraction efficiency and device thickness.
2Use of energy by moving object
If reflective surface is slanted to achieve total internal reflection, then light is reflected to sides, but device thickness increases
Solution Approach 1:
The patent changes the optical parameters of the reflector layer by using particles with high refractive index and strong scattering properties. Instead of relying on geometric slanting (which increases thickness), the patent achieves side-directed reflection through optical parameter optimization - specifically, using particle materials and size distributions that create strong angular redistribution and total internal reflection effects in a planar, thin configuration.
3Object-generated harmful factors
If scattering material has substantial thickness to prevent light from leaving through top surface, then light is contained, but device thickness increases
Solution Approach 1:
The patent uses composite materials in the reflector layer that combine high-refractive-index scattering particles with reflective particles. This composite structure achieves strong light containment and angular redistribution in a much thinner layer than conventional scattering materials alone, because the reflective particles provide additional optical paths that trap light within the device while the scattering particles provide angular redistribution.
Solution Approach 2:
The single reflector layer performs multiple functions simultaneously: it reflects light, scatters light for angular redistribution, and contains light to prevent escape through the top surface. This multi-functionality is achieved through the composite particle structure, where different particle types contribute different optical functions, eliminating the need for separate layers for each function and reducing overall device thickness.
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 thin side-emitting device with increased light extraction efficiency and the ability to tailor light color without increasing device size, while preventing light emission through the top surface.
Implementation Method 1
The reflector is essentially opaque and a scattering component, such that light incident thereon from any angle of incidence is reflected and scattered
Implementation Method 2
light incident thereon from any angle of incidence is reflected and scattered
Implementation Method 3
The scattering action gives rise to an angular redistribution in the device, which increases the chance of light exiting the device at all
Implementation Method 4
the light emitted by the LED will be subject to wavelength conversion, and the color of the light output can be tailored to the need of the user
Implementation Method 5
less light is reflected from the high refractive index LED material to a higher index solid layer that to for example, air. In addition, the critical angle of total internal reflection is increased by a solid body
Data Source
AI summary
A side-emitting light emitting device (100) is provided, comprising at least one light emitting diode (101) arranged on a substrate (102) and facing a scattering reflector (103, 109) disposed at a distance from and extending along the extension of said substrate. The reflector comprises a plurality of non- parallel oriented reflective flakes (112) distributed in a transmissive carrier (113), such that light incident thereon from any angle of incidence is reflected and scattered. The scattering action of the reflector gives rise to an angular redistribution in the device, which increases the chance of light exiting the device through lateral openings between the reflector and the substrate, while the opacity of the reflector prevents light from being emitted through the top surface.