Superior Alternative to Traditional UV LED Sources

Phoseon’s new, high intensity, scalable, long-life UV light system has significant advantages over standard UV-LED systems.

Traditional UV LED sources utilize the unique properties of semiconductors which were first reported by Michael Faraday in 1883.  A high level overview of how semiconductors can be used to produce light follows: 

Materials can be grouped by their ability to support a flow of electric current as follows: 

• Insulators with no current flow
• Conductors where current flows easily
• Semiconductors with limited current flow that is a function of temperature

In the semiconductor manufacturing process, impurities (or dopants) are added to the base semiconductor material to add either free electrons (in negative or n-type regions) or create holes to attract electrons enabling current flow (in positive or p-type regions).  Semiconductor light-emitting diode (LED) technology consists of a p-n junction formed by two dissimilarly doped semiconductors.  When no external voltage is applied, the electrons near the junction zone balance and there is no current flow.  When an external electric voltage bias is applied across the junction, current can be made to flow, and when the holes from the p-type and electrons from the n-type meet at the junction and combine, a photon of light is released (see Figure 1). 

The wavelength of the light emitted is a function of the bandgap energy of the materials used in the p-n junction (bandgap energy refers to the energy threshold that electrons must pass in order to flow across the junction).  The more aluminum added to the semiconductor material, the shorter the output wavelength. However, with increased aluminum content in the semiconductor material, it becomes harder for electrical current to flow and the semiconductor material becomes much harder to grow in the manufacturing process. By adjusting the materials used and the doping (i.e., the depositing of n-type or p-type impurities into the silicon), a wide range of wavelengths are possible, including wavelengths in the ultraviolet (UV) portion of the electromagnetic spectrum. 

SLM Technology, a high-intensity alternative to discrete UV LEDs

UV light sources constructed with semiconductor based light emitting devices could be as simple as an array of discretely packaged UV LEDs.  However, the light produced by such an approach will be inherently limited by the existing LED package design.  A better approach to address industrial applications is to customize the packaging, optics, and thermal design to optimize the output (Figure 2).

Phoseon’s Semiconductor Light Matrix (SLM) technology combines a dense array of UV LED semiconductor devices, with micro optics and advanced thermal management technology in a cost-effective MOEMS (micro opto electro-mechanical system) package. The result is a high intensity UV light system that offers an efficient, scalable, safe, long-life, and environmentally friendly alternative to traditional UV LED sources.

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