Semi-Transparent Metal Coating for LED Chip Light Dimming
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Solution Overview
Problem
Standard solid-state lighting devices, such as LEDs, face challenges in achieving desired brightness levels due to high brightness output, which is difficult to manage with existing chip platforms, necessitating a solution for adjustable dimming capabilities.
Innovation Solution
A semi-transparent metallic layer, such as titanium or platinum, is deposited on the LED chip, which can be adjusted in thickness to control light output, and is electrically isolated from the active LED structure using a passivation layer, allowing for varied dimming levels without affecting the LED's electrical coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a metallic layer is deposited on the LED chip to reduce light output, then dimming capability is improved, but electrical coupling between the metal layer and LED structure may be affected
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the metallic layer and the LED structure. This dielectric layer serves as both an electrical insulator to maintain proper electrical coupling and isolation, and as an optical medium that allows the metallic layer to effectively dim the light output. The dielectric layer prevents direct electrical contact while permitting the metallic layer to interact with the emitted light for dimming control.
2Illumination intensity
If the metallic layer thickness is increased to achieve greater dimming, then light output control is improved, but the complexity of manufacturing increases
Solution Approach 1:
The patent utilizes control of the metallic layer thickness as a key parameter to achieve different dimming levels. By varying the thickness of the metallic layer deposited on the LED chip, different amounts of light are blocked or absorbed, providing a range of dimming effects. This parameter-based approach allows for tunable dimming control without requiring fundamentally different manufacturing processes.
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 approach enables a single LED chip platform to meet multiple brightness requirements by modifying the metallic layer's thickness, providing a range of dimming options while maintaining the LED's efficiency and electrical insulation.
Implementation Method 1
A semi-transparent metallic layer, such as titanium or platinum, is deposited on the LED chip, which can be adjusted in thickness to control light output
Implementation Method 2
a passivation layer between the metallic layer and the active LED structure, so that the metallic layer is electrically isolated from the active LED structure
Implementation Method 3
the metallic layer can be sputter deposited on to the passivation layer, where a length of time the metallic layer is sputter deposited, can be based on the amount of dimming desired
Data Source
AI summary
Solid-state lighting devices including light-emitting diodes (LEDs) and a semi-transparent metallic layer deposited on an LED chip that can dim a light output of the LED chip are disclosed. The thickness of the semi-transparent metal layer can be adjusted based on the desired dimming level. In an embodiment, the metallic layer can be deposited on top of a passivation layer over the LED structure, so that the metallic layer is not electrically coupled to the LED. The metallic layer can additionally cover the mesa sidewalls of the LED structure. The metallic layer can be titanium, or platinum, or other suitable metals in other embodiments. In an embodiment, the metallic layer can be deposited on to the passivation layer, where a length of time the metallic layer is deposited, can be based on the amount of dimming desired.