There are many terms used to specifically describe the various aspects of fluorescent lighting and the technology behind the engineering and manufacturing of them. One such term used to help define color in fluorescent light is CIE (Commission Internationale de l’Eclairageis), the international standards organization that sets the standards for color and color measurement.
Fluorescent lamps may be described as cold cathode. This type of lamp has a cylindrical metal shell (electrode) covered on the inside with an emission coating. Cold cathode lamps are not heated to induce thermionic emission of electrons such as in hot cathode lamps, but rather, their interior surface produces secondary electrons upon electron and ion impact. To accelerate ions to a sufficient velocity in order to create free electrons, cold cathode lamps require higher voltages than hot cathode lamps.
Hot cathode lamps usually have a higher power density than cold cathode lamps and emit more electrons from the same surface area, which results in a higher output and the ability to operate at a higher lamp current. Generally the lamps have a tungsten filament covered with an emissive layer made of material with lower work function that emits electrons better than bare tungsten metal. The filament is either directly heated, where the filament itself is the source of electrons, or indirectly heated, where the filament is electrically insulated from the cathode.
Another important term in fluorescent lighting is CRI (Color Rendering Index), which quantitatively measures a light source’s ability to render color on a scale of 0 to 100 percent and is independent of color temperature. If the light has a CRI of 85 to 90 percent, it is considered good at color rendering. A rating of 90 percent or above, offers the most accurate color discrimination. If you need more information and clarification on our lamps, please see our website.
LightSources and our affiliated companies represent the leading high-tech designers and manufacturers in the lamp industry today. Our products are used world-wide in a multitude of applications and industries such as our avionic display backlighting that is part of the National Defense and US Space Program. Please contact us to learn more about our extensive selection of lamps.