Light Emitting Device Dual Light Guide Spectral Conversion
Solution Overview
Problem
Existing light emitting devices suffer from excessive light loss and inadequate spectral distribution, particularly for white light sources, due to inefficient light coupling and conversion in prior art devices, leading to reduced intensity and a narrow wavelength range.
Innovation Solution
A light emitting device comprising a first light guide and a second light guide, where the first guide receives light from a source, guides it to an end surface, and couples it into the second guide, which converts the light to a broader spectral distribution, thereby minimizing light loss and incorporating non-converted blue light, resulting in a high-intensity, multi-color light source with improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single light guide with luminescent material is used to convert light wavelengths, then light conversion efficiency is improved, but light loss increases and spectral distribution becomes narrow
Solution Approach 1:
The invention divides the light guide system into two separate light guides: a first light guide for transmitting non-converted blue light and a second light guide for converting light to longer wavelengths. This segmentation allows each light guide to be optimized for its specific function, preventing light loss in the first guide while achieving broad spectral distribution through the second guide's conversion capabilities.
Solution Approach 2:
The first light guide acts as an intermediary element that captures and transmits the blue light portion that would otherwise be lost in conventional single light guide designs. This intermediary structure enables the blue light to be directed to the light exit surface while the second light guide handles the converted wavelengths, achieving both high efficiency and broad spectral coverage.
2Illumination intensity
If blue light is completely converted to longer wavelengths in the conversion structure, then light intensity is improved, but spectral distribution becomes inadequate for white light sources
Solution Approach 1:
The invention applies different optical properties to different parts of the system: the first light guide is designed with properties suitable for transmitting blue light (including potential reflective coatings on side surfaces), while the second light guide is designed with luminescent material for wavelength conversion. This local differentiation of optical qualities allows blue light to be preserved in the first guide while conversion occurs in the second guide, achieving both intensity and spectral breadth.
Solution Approach 2:
Instead of completely converting blue light to longer wavelengths as in conventional designs, the invention inverts the approach by preserving the blue light portion and transmitting it separately through the first light guide to the exit surface, while using the second light guide to add converted wavelengths. This inversion of the complete conversion strategy maintains blue light intensity while achieving broad spectral distribution.
3Productivity
If converted light is extracted from the light guide surface, then light extraction efficiency is improved, but non-converted light escapes from side surfaces resulting in reduced efficiency
Solution Approach 1:
The invention segments the light extraction function between two light guides: the first light guide is configured to extract and transmit non-converted blue light from its side surfaces to the light exit surface, while the second light guide extracts converted light at wavelengths suitable for the application. This segmentation prevents the loss of blue light that would otherwise escape uselessly in single light guide designs.
Solution Approach 2:
The invention utilizes the spatial dimension by directing blue light from the first light guide to exit through a light exit surface that is perpendicular to the input surface, creating a three-dimensional light extraction pathway. This dimensional approach allows blue light to be captured and redirected to the exit surface rather than being lost from side surfaces, while converted light from the second guide is extracted at appropriate wavelengths.
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 minimizes light loss and broadens the spectral distribution of emitted light, making it suitable for white light sources by effectively utilizing non-converted blue light and enhancing light intensity through efficient coupling and conversion processes.
Implementation Method 1
a first light guide (3) adapted for receiving light (13) with a first spectral distribution from the light source (2) at a first light input surface (31), guiding the light (13) with the first spectral distribution to a first light exit surface (32) and to an end surface (35)
Implementation Method 2
a second light guide (4) adapted for receiving the light (13) with the first spectral distribution coupled out of the first light guide (3) at a second light input surface (41), guiding the light (13) to a second light exit surface (42), converting at least a part of the light (13) with the first spectral distribution to light (14) with a second spectral distribution
Data Source
AI summary
A light emitting device (1) comprising a light source (2) adapted for, in operation, emitting light (13) with a first spectral distribution, a first light guide (3) comprising a first light input surface (31) and a first light exit surface (32) arranged opposite to one another, and further comprising an end surface (35) extending perpendicular with respect to the first light input surface (31), and a second light guide (4) comprising a second light input surface (41) and a second light exit surface (42) extending perpendicular with respect to one another. The first light guide (3) is adapted for receiving the light with the first spectral distribution from the light source (2) at the first light input surface (31), guiding the light with the first spectral distribution to the first light exit surface (32) and to the end surface (35) and coupling a part of the light with the first spectral distribution out of the first light exit surface (32) into the second light guide (4) and coupling another part of the light with the first spectral distribution out of the end surface (35). The second light guide (4) is adapted for receiving light with the first spectral distribution coupled out of the first light guide (3) at the second light input surface (41), guiding the light to the second light exit surface (42), converting at least a part of the light (13) with the first spectral distribution to light (14) with a second spectral distribution and coupling the light with the second spectral distribution out of the second light exit surface (42).