Inverted LED Light Mixing via Transparent Dielectric Layer
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Solution Overview
Problem
Conventional surface light source display modules using LED light sources face limitations in light mixing and uniformity, with methods like diffuser plates and lenses resulting in dark areas and non-uniform brightness, and the use of fluorescent powder leading to attenuated light intensity and poor lateral propagation.
Innovation Solution
A light emitting device with a substrate and LED light sources having a first reflecting layer on their top surface, allowing light to emit from four sides, and a transparent dielectric layer covering the LED light sources, which enhances light mixing and uniformity by increasing the light emitting angle and facilitating even light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a diffuser plate is disposed at a position above the LED light source array, then the point light source is turned into a surface light source, but dark areas are formed and light mixing is non-uniform
Solution Approach 1:
The patent changes the light emission from a single upward direction to four sides by inverting the LED and adding side-emitting structures. This dimensional change in light propagation allows light to travel laterally through the transparent dielectric layer, improving mixing uniformity without forming dark areas.
Solution Approach 2:
The transparent dielectric layer acts as an intermediary medium that facilitates light propagation and mixing from the inverted LED sources. It enables lateral light transmission and coupling between adjacent LEDs, achieving uniform light distribution without the drawbacks of diffuser plates.
2Illumination intensity
If a lens is installed close to the LED light source, then light is transmitted through the lens and air layer to the diffuser plate, but dark areas are formed and light mixing is non-uniform
Solution Approach 1:
The patent eliminates the need for lenses by inverting the LED to emit light in multiple dimensions (four sides). This removes the optical concentration effect of lenses that creates hot spots and dark areas, achieving uniform illumination through lateral light propagation in the dielectric layer.
Solution Approach 2:
The patent extracts and removes the lens component from the system entirely. By using inverted LEDs with side emission capabilities, the function of light direction and distribution is achieved without requiring additional optical elements like lenses, simplifying the structure and improving uniformity.
3Illumination intensity
If silica gel and fluorescent powder are directly coated on the LED light source array, then a light-guide medium layer is formed, but light emitted by the LED light source is not conducive to lateral propagation and the lateral propagation effect is limited
Solution Approach 1:
The patent inverts the conventional LED orientation and coating approach. Instead of coating fluorescent powder on top of upward-emitting LEDs, the LEDs are inverted to emit light downward and laterally into the transparent dielectric layer, enabling effective lateral propagation without relying on fluorescent conversion.
Solution Approach 2:
The patent changes the optical parameters by using a transparent dielectric layer with appropriate refractive index instead of fluorescent powder-containing layers. This parameter change enables better lateral light propagation and coupling by matching impedance and reducing total internal reflection at interfaces.
4Device complexity
If the light emitting angle of the LED light source is limited to 120 degrees, then the LED structure is simple, but the light mixing effect is poor and uneven brightness occurs
Solution Approach 1:
The patent achieves a wide effective emission angle without modifying the LED chip structure by inverting the LED and utilizing lateral light propagation in the transparent dielectric layer. The light travels laterally through the dielectric medium, effectively increasing the illumination coverage area without requiring complex wide-angle LED designs.
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 significantly improves light mixing and uniformity, achieving a high dynamic range of 20000:1 and reducing the number of LED light sources required, while simplifying the production process and reducing costs.
Implementation Method 1
The first reflecting layer on the top surface of the LED light source can reflect part of light to side surfaces of the LED light source
Implementation Method 2
the light can be diffused more evenly, and the light of each LED light source can transmit and couple in the transparent dielectric layer
Data Source
AI summary
The present disclosure provides a light emitting device and a method for fabricating the same. The light emitting device comprises: a substrate; a plurality of LED light sources, wherein the LED light source adopts a package form emitting light from four sides and having a reflection layer on a top surface, and the plurality of LED light sources are disposed on the substrate at intervals; and a transparent dielectric layer being disposed at a surface of the substrate and covering the plurality of LED light sources. The invention can be used to improve light-mixing effects.