Why is the red sector a denser colour than the blue or green sectors, or at least on 2 makes I've looked at, or would more objective/scientific analysis show the same colour density? It seems to mean that if the lamp becomes under-powered or dirty integrator/ light tunnel etc then the reds become brown or plum , unless projected onto a small screen area
Why should they be identical to the eye? The eye is less sensitive to red and blue than green. And red and blue wavelengths cover a narrower part of the spectrum than green, so less visible light gets through.
objective/scientific
and
For both makes, completely different sizes etc, the transmissivity , by eye, of the blue sector matches the green sector . This projector is used for graphical displays and red indistinguishable from black at the usual diagonal is a problem. Cleaning the UV filter at the C/W and cleaning the surfaces of the integrator tunnel has improved things a bit but not enough. Orange or pink would probably be alright for this use instead of red but dark brown or dark plum is not. I just tried a scrapped dichroic C/W and it is quite easy to scrape lines in the coating , say 10 percent , to pass something more like an orange colour. Anyone ever done this to get round underpowered lamp problem and red/brown issue? Would heat build up from the multiple scratches compared to just the
3 butt joins of the glass sectors , as made Why dichroic for primary colours transmission and reflection of the complement. In dichroic lamp reflectiors I can see a point in that it reflects the visible light and transmits the heat through the glass to be delt with by fans. I cannot see that reflecting the complement is a by-product of reflecting IR or UV back to the lamp.Instead of destroying NASA tech, I decided to open up the hole in the mask between lamp and C/W, to see if getting more light will help, even if off principal axis. At least I can put a mask back if there is too much colour spill over from adjascent sectors, a more extreme version of adjusting the C/W delay . That did not work because if red is brown then brown does not become pinker by losing some red and gaining some blue from the sector on that side or going orange by losing some red and gaining some green from the other adjascent sector
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.