High Intensity Discharge bulbs

High Intensity Discharge (HID) bulbs contain the following types of lamps: mercury lamps, metal halide lamps (also known as HQI), high pressure sodium lamps, low pressure sodium lamps, high pressure mercury lamps, and rare short arcs Xenon lights. The light-emitting element of these bulb types is an arc discharge arrester placed in a high-temperature lamp (arc tube) and has a luminous power of more than 3 W / cm² (19.4 W / in²).

HID lamp through a special design, the internal cloth coated quartz or aluminum lamp, and through the two ends of the tungsten electrode hit out of the pressurized arc, through the lamp after the light. These lamps are filled with gas and metal. The gas helps the bulb to start, and the metal heats up to the point of evaporation, forming a plasma state and emitting light.

Types of HID lamps include:

Mercury lamps (CRI range 15-55)

Metal halide lamp (CRI range 65-80, ceramic halogen lamp is up to 90)

Low pressure sodium lamp (CRI 0, because of its monochromatic light)

High pressure sodium lamp (CRI range 22-75)

Mercury bulbs were originally used to produce green light, is the first commercial HID bulbs. Today, these bulbs have been able to correct out closer to the white light. But the mercury lamp has been gradually updated, more efficient high-pressure sodium lamp and metal halide lamp replaced. Standard low-pressure sodium lamps have the best efficiency in all HID bulbs, but they emit light in yellow. High-pressure sodium lamps are now able to send out more white light, but the number of sacrificed some efficiency. Metal halide lamps are less efficient but can emit more whiter, more natural light, and there are many colored metal halide lamps available.