A Guide to Transformative Lighting Solutions

Lighting Solutions

High Pressure Sodium-Vapor Lamp

The high-pressure sodium-vapor lamp is a discharge lamp, which means that the lamp emits light following the excitation of gas by electrical discharges.  Specifically, photons are emitted when gas molecules experience changes in energy levels due to the flow of electrons. These changes in energy levels are called “electronic transitions”.

The light created by an HPS lamp is propagated in all directions, so 360 degrees. That's why the device is frequently deployed in tandem with a reflector, so the light is redirected to the target growth surface.

The light emission produced by a gas-based reaction is characterized by a spectrum whose wavelengths are primarily situated between 550nm and 700 nm, which gives the light an amber color. In other words, the wavelengths emitted by a discharge lamp are specific to the gas involved and its excitation properties. For example, in the spectrum graph below, see the spectrum of an HPS lamp.

White Light LED

The light-emitting diode (LED) is an optoelectronic component. In other words, an LED   is a light source that emits light when the electronic component is activated by, an electrical current. In brief, photons are emitted when electron recombination (emissive transitions) occur between the portion of the semiconductor with an electron deficit and the portion of the semiconductor with an excess of electrons.

There are two principal methods for creating white light with LED technology. The first is called “phosphorus conversion,” which entails covering a blue light-emitting LED with phosphorus, whereas the second consists of blending red, blue and green colored lights.

–   Phosphorus Conversion

White LEDs came about in the 1990ies thanks to the development of the blue high- power LED. The application of a phosphorescent coating on the semiconductor enables the production of a spectrum that extends to red based on the original, highly constrained spectrum of a blue LED.

Phosphorus conversion white LEDs emit a broad spectrum of light, albeit without adhering to the proportions of natural light for a given spectrum. With regard to the color proportions relative to the entire spectrum, the peak in the blue segment (located between 450 and 470 nm) compensates for the absence of light on either side of these wavelengths. Compared to the complete spectrum of sunlight, there is a significant portion of colors missing between 470 and 505 nm of the spectrum between the blue and green of a white LED – the portion known as cyan. Moreover, the presence of colors in the red section of the spectrum doesn't conform to natural light, that is to say that daylight has a spectrum which extends well beyond that which is visible to the human eye.