Almost 400 years have passed since Christiaan Huygens invented the first "Magic Lantern" projector. Before the invention of electricity, projectors used a kerosene lamp as a light source. Therefore, the design of the first projectors was similar to a kerosene lamp.
Of course, modern projectors are radically different from their prototypes. As known, its brightness directly affects the quality of the projection. Therefore, lamp improvement has become one of the main directions in the process of improving projectors. Basically, their evolution ended in 1995 when Philips developed the high pressure mercury UHP (ultra high performance) lamp.
Today lamp projectors use modern UHP lamp modifications.
Introduction
At the turn of the century, the semiconductor industry was able to provide relatively cheap and powerful LEDs. Their miniature size and work without overheating have become a huge plus compared to lamps and projector developers haven't missed new opportunities. As a result, companies have developed a huge number of LEDs models, including the very popular ultraportable mini projectors.
The addition of an optical cavity to the LED ushered in the era of miniature laser LEDs.
They have become an ideal light source in mini projectors because of the perfect focusing of coherent radiation. Of course, laser LEDs also have disadvantages, including laser speckle and high cost.
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