Originally Posted by Bydlofication
Do DLP and 3-DLP chips and optical systems wear out, causing dimming or blurring? I read that after the first replacement of the lamp on 1 dlp beamer, you can get up to minus 50% of the perceived brightness compared to the new projector. Is it true?
In a ideal world no. DLP projectors can be designed for 24/7 long-term use with MTBF mean time between failure of in excess of 30,000 hours or 50,000 hours or 100,000 hours, as long as preventative maintenance of color wheel replacement at 8,000 hours or more and system fan replacement at 16,000 hours or more is carried out. They can work as good as the day they were new after many tens of thousands of hours of use.
In the real world the answer is yes sort of. Dust in the light path often on the color wheel can reduce lumen output. Bleaching of the light path often of the light dump/sink can reduce contrast. Dust in the focus plane often on the DLP chip can cause visible dust bobs, blobs of lighter grey on a black image. And the projector lens may get out of perfect alignment with the DLP chip if the lens is manhandled, resulting in loss of uniform image focus.
More detailed answer.
Lamp based DLP projector light path.
Lamp. The lumen rating is for a new lamp, lamp life is 50% of lamps still working at 50% or more of original lumen output. The lamp life figure also makes assumptions about frequency of switching the lamp on and off. While lumen output is typically at projector native color space with all light boosting features on maximum, not calibrated for video. And figures are for official lamp modules not compatibles.
Glass UV shield to protect light path. Can get covered in dust. I think they can also go off color with age or wear out but am unsure. Depending on the projector maybe part of the lamp casing, or part of the projector, or not present at all. Removing the UV shield will boost lumen output, but overtime damage the light path.
Color Wheel only used in single chip DLP projectors. Often attracts dust reducing projector lumen output. How quickly and how much dust collects on the color wheel is dependent on projector design and environment. Color wheels also wear out overtime and can go out of sync.
Light integrator. Typically a mirrored tunnel or glass rod. A hollow mirrored tunnel can suffer heat damage and collapse with age but is unlikely to collect much dust. A glass light integrator rod has higher reliability and but can suffer from loss of lumen output due to dust gather on the glass light integrator rod.
The following are typically in the sealed part of the light path. Modern DLP projectors appear to have better sealing of their light paths than older DLP projector designs.
Focusing lenses and mirrors can lose lumen output due to dust. Mirrors can also get tarnished with age depending on environment, and if tarnished will reduce lumen output.
DLP chip. Typically rated at 100,000+ hours. should not degrade lumen output or contrast overtime. At least not if UV shielding of the light path is working. Dust blobs on the DLP chip can be a problem. Those projectors with TIR prisms seem immune to dust blobs on the DLP chip probably due to the TIR prism being attached to the DLP chip. Also as previously mentioned modern DLP projectors appear to have better sealing of their light path than older designs.
TIR prism. Used in three chip DLP projectors to combine the light output of the three chips, and used in some single chip DLP projectors to enable lots of variable lens shift / projector placement flexibility. Note TIR prism designed single chip DLP projectors inherently have lower contrast but better black uniformity than offset single chip DLP projector designs, due to the light source - lens angles used.
Light dump/sink. Depending on how made can overtime get bleached by light reducing contrast.
Projector lens, once again dust is the enemy. Also depending on environment it is possible for moisture to get inside the lens reducing lumen output and contrast and making the image look foggy. And if improbably cleaned it is possible to destroy the lens anti-reflective coatings reducing contrast and increasing chromatic aberration, or scratch the lens. And if manhandled can go out of perfect alignment with the DLP chip resulting in loss of uniform image focus.