LED Reflector Via Layout for Brightness-Voltage Balance
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Solution Overview
Problem
Existing light-emitting devices face challenges in balancing luminous efficiency and voltage, as increasing the number of conductive via in the light-transmissive dielectric layer improves current spreading but reduces the omnidirectional reflector mirror area, leading to decreased brightness, while reducing their number enhances reflection efficiency but increases voltage.
Innovation Solution
A light-emitting device design featuring a semiconductor epitaxial structure with a light-transmissive dielectric layer having through holes filled with a reflection layer, where the ohmic contact layer has a larger contacting surface area than the through holes, optimizing current spreading and reflection efficiency while maintaining a sufficient contact area for lower voltage operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of conductive via in the light-transmissive dielectric layer is increased to improve current spreading, then voltage is lowered, but the omnidirectional reflector mirror area is reduced and luminous brightness decreases
Solution Approach 1:
The patent applies local quality by creating different regions within the light-transmissive dielectric layer: regions with through holes for current injection and regions without through holes for light reflection. This allows different areas to serve different functions - current conduction and light reflection - simultaneously, resolving the contradiction between needing conductive vias for low voltage and needing mirror area for high brightness
2Ease of operation
If the number of conductive via in the light-transmissive dielectric layer is increased to improve current spreading, then current spreading is enhanced, but the omnidirectional reflector mirror area is reduced
Solution Approach 1:
The patent segments the light-transmissive dielectric layer into multiple regions: some regions contain through holes for current injection while other regions remain intact to serve as reflection mirrors. This segmentation allows the structure to simultaneously provide both current spreading pathways and light reflection surfaces, resolving the contradiction between current spreading and mirror area
3Illumination intensity
If the number of conductive via in the light-transmissive dielectric layer is decreased to increase the omnidirectional reflector mirror area, then reflection efficiency is improved and luminous brightness increases, but voltage is increased
Solution Approach 1:
The patent makes the light-transmissive dielectric layer multi-functional by allowing it to serve both as a current conduction medium (through regions with through holes) and as a light reflection medium (through regions without through holes). This universality resolves the contradiction between needing mirror area for high brightness and needing conductive vias for low voltage operation
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
This design maximizes the mirror reflection area at lower voltages, enhancing both the luminous brightness and efficiency of the light-emitting device by balancing current spreading and reflection efficiency.
Implementation Method 1
a metal reflection layer and a light-transmissive dielectric layer are disposed on a side of the metal bonding layer and cooperatively form an omnidirectional reflector (ODR) structure, which reflects light from the metal bonding layer to the light exiting side
Implementation Method 2
a light-transmissive dielectric layer is disposed on the ohmic contact layer away from the semiconductor epitaxial structure
Implementation Method 3
An ohmic contact layer is disposed on the second surface of the semiconductor epitaxial structure
Data Source
AI summary
A light-emitting device includes a semiconductor epitaxial structure that has a first surface and a second surface opposite to the first surface, and that includes a first type semiconductor layer, an active layer, and a second type semiconductor layer sequentially disposed in such order in a thickness direction from the first surface to the second surface. An ohmic contact layer is disposed on the second surface of the semiconductor epitaxial structure, and a light-transmissive dielectric layer is disposed on the ohmic contact layer away from the semiconductor epitaxial structure. The light-transmissive dielectric layer has a plurality of through holes. A reflection layer is disposed on the light-transmissive dielectric layer and fills the through holes so as to be electrically connected to the ohmic contact layer.