The currently used light sources mainly include: UHP lamps (super lamps), UHE lamps, and metal halide lamps
UHP bulbs are an ideal cold light source, but they are generally used in high-end projectors due to their high price. UHP lamps produce cold light, small form factor, can generate a large amount of light at the same power consumption, have a longer life, and instantly extinguish when they fail. The advantage is that it has a long service life. Normally it can be used normally for more than 4,000 hours, and its brightness decay is very small.
In 1995, the Philips company in the Netherlands first developed an ultra-high pressure mercury lamp with a distance of about 1.3 mm and a power of 100 watts. When the lamp is working, the mercury vapor pressure can reach 200 atmospheres. The higher the mercury vapor pressure, the higher the brightness of the lamp, and the larger the spectrum width of the mercury atom, the more complex the spectrum of the continuous spectrum of the molecule and the charged particles, especially the red light radiation above 595 nm rises with the working pressure inside the lamp. High and enhanced, thus improving the color rendering of the lamp. As the lamp discharges at an extremely high temperature, the tungsten material evaporates and deposits on the wall of the ball, causing light decay. Now, the lamp is filled with traces of oxygen and halogen in the process to effectively clean the bulb and make the lamp Life of 12,000 hours.
UHP light source arc brightness can exceed 1Gcd/m2 required for small-area high-efficiency projection equipment, in order to achieve better light collection effect, in recent years UHP light source arc pole pitch reduced to 1.0mm, its life of more than 10,000 hours, power is 200 watts, equipped with projector products, weighs only 4 kg, volume less than 2 liters, easy to carry, and its screen illumination exceeds 1100 lumens, capable of achieving bright XGA display levels.
UHE bulbs are also a kind of cold light source. UHE bulbs are the ideal light source widely used in mid-range projectors. The advantage is that the price is moderate, and the brightness is hardly attenuated until 4000 hours have elapsed.
The metal halogen bulb has a high heat, which requires a high degree of heat dissipation for the projector and should not be used for a long time (more than 4 hours). The metal halide lamp generates warm light, requires more power to produce the same illuminance as the UHP lamp, and has a short service life. Unlike the UHP lamp, the metal halogen lamp shows a gradual extinction when it is bad. Metal halide bulbs have the advantage of being cheap and have the disadvantage of having a short half-life. Generally, the brightness is reduced to about half of the original in about 1000 hours.