AC-Operated UV LED Array with Inverted Polarity
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Solution Overview
Problem
Ultraviolet light emitting diodes (UV LEDs) currently require direct current (DC) for operation, which is inefficient and costly due to the need for additional conversion equipment when used with standard alternating current (AC) power sources in most households and buildings.
Innovation Solution
UV LEDs are designed to operate with alternating current by connecting discrete LEDs with opposing polarity, allowing them to alternate between forward and reverse bias with each half-cycle of the AC cycle, resulting in continuous illumination and reduced heat accumulation and increased energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If UV LEDs are operated with direct current (DC), then the LEDs can emit ultraviolet light, but additional conversion equipment is required when using standard AC power sources, increasing device complexity and cost
Solution Approach 1:
The patent inverts the conventional approach by designing UV LEDs that operate directly with AC voltage instead of requiring conversion to DC. The LED structure incorporates opposing polarity connections that allow it to function during both positive and negative half-cycles of the AC waveform, eliminating the need for rectifiers and power conversion circuits.
Solution Approach 2:
The UV LED device is designed to accept standard AC power input (110-120V or 208-240V) directly, making it universally compatible with existing household and building power infrastructure. This multi-functional design allows the same device to operate without requiring separate DC power supplies or conversion equipment.
2Duration of action of stationary object
If UV LEDs are connected in series and parallel arrays, then continuous ultraviolet illumination is achieved during AC operation, but the device structure becomes more complex
Solution Approach 1:
The UV LED device is divided into multiple individual LED chips arranged in series and parallel arrays. Each chip is independently connected to handle different phases of the AC cycle. This segmentation allows continuous UV emission as different segments are activated during different half-cycles of the AC waveform.
Solution Approach 2:
The series and parallel array configuration ensures that at least one LED chip is always conducting and emitting UV light during any given moment of the AC cycle. The opposing polarity connections and array arrangement maintain continuous useful action by transitioning smoothly between different active segments during voltage polarity changes.
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 configuration enables UV LEDs to function efficiently with standard AC voltages, providing continuous ultraviolet radiation while minimizing heat accumulation and optimizing energy utilization, thus addressing the inefficiencies of DC operation.
Implementation Method 1
an ultraviolet light emitting diode with a first biased diode connected in a parallel circuit with a second biased diode, wherein the ultraviolet light emitting diode emits ultraviolet light when energized with alternating current
Data Source
AI summary
Ultraviolet light emitting illuminator, and method for fabricating same, comprises an array of ultraviolet light emitting diodes and a first and second terminal. When an alternating current is applied across the first and second terminals and thus to each of the diodes, the illuminator emits ultraviolet light at a frequency corresponding to that of the alternating current. The illuminator includes a template with ultraviolet light emitting quantum wells, a first buffer layer with a first type of conductivity and a second buffer layer with a second type of conductivity, all deposited preferably over strain-relieving layer. A first and second metal contact are applied to the semiconductor layers having the first and second type of conductivity, respectively, to complete the LED. The emission spectrum ranges from 190 nm to 369 nm. The illuminator may be configured in various materials, geometries, sizes and designs.