Compact LED projector with tapered light pipes for moderate light output applications

LED-based projectors have numerous advantages compared to traditional projectors. They are more compact, exhibit a larger color gamut and a longer lifetime, the supply voltage is lower and they can even operate on batteries. Despite their optical power per étendue is significantly lower than that of an UHP-lamp, they can be used in low power applications.In this paper, we will present a very compact architecture that produces almost 60 lm D65 light with one red, one green and one blue LED and three small LCOS panels (0.64 in.). In this architecture we have replaced the collection lenses, light pipes (or lens arrays) and relay lenses by ‘Gradually Tapered Light Pipes’.