In general a LASER illuminated projector is going to use three separate LASER LEDs - one for each color.
A single LASER-powered source that can deliver white light can be done...
But it's far more expensive... and it hardly makes sense to pay extra for that and then split it again with filters.
HOWEVER...
- A plastic lens is more likely to deteriorate or yellow than a glass one.
- But the actual color of a glass filter can also fade or change with time and light exposure.
(The glass won't change but the dye or phosphor can still age and fade.)
Of course, things like LEDs or LASERs generate far less heat than old-style lamps, and should have a greater lifespan.
(Note, however, that not all LEDs have a very long rated life, especially really powerful ones, so it is worth checking about that.)
I have no first hand ex-with Sony Projectors, but I am certain the lens in my JVC RS3000 uses 100% glass. JVC has extensive descriptions on their website.
SONY projector lenses are probably all glass, as well. Don't forget that SONY makes a line of well regarded glass for their SLR / DSLR / Mirrorless line of cameras. They compare well, on a lens-to-lens basis with Canon, Nikkor and Pentax....and others.....
But it's not the glass to the screen that counts.....it is the INTERNAL lenses, mirrors and filters used in the LIGHT ENGINE. They are exposed to some wacky high intensity light and depending on source, maybe some stuff you don't want.....UV? I don't know.
I don't know, but JVC and EPSON and others probably have glass made TO SPEC (and price) by an aftermarket company. In the camera world? Companies like Tamron, Sigma and now 7Artisans all make glass for the big camera brands.....
Modern camera lenses use half a dozen or more different kinds of 'glass'.....including molded plastic! (Your CR39 glasses are cheap and optically real good) as well as several kinds of coatings and even NON SPHERICAL shapes.
My Nikon Zoom? Uses even Short Wavelength glass, Aspheric, Fluorite and more. Not to mention 2 or more coatings as well as being weather sealed....so you can get caught in the rain without destroying your gear......
Modern Projector lenses especially with Keystone and other 'corrections' possible are VERY well done......
At work? We had HIGH END steppers and projection (mask) aligners for the semiconductor industry. I ONE KILOWATT UV BULB is expensive and a mess to clean if it 'pops'.....usually the result of a fingerprint or other contamination.....But ONE thing for sure, is that they are
expensive and MURDER on any filters. That kind of intensity and spectrum exposure is tough. And you simply can't have random failures. Downtime / rework / Scrap is a LOT OF MONEY and not tolerated.
THOSE kinds of machines used special, HEAT PROOF GLASS. SONY knew about this going in. They were a MULTIPLE Patent Holder in the light engine 'space' but ignored some simply because they were cheap rat-bastards.
I got the TV deal as well and sold it IMMEDIATELY upon receipt, still IN BOX. And went and bought a Panasonic Plasma. Sony couldn't even be bothered to replace my 65" with ANOTHER of like size.......
www.lightbulbs.com/product/sylvania-69228/?source=GooglePPC-ProductAds Picture of high pressure mercury vapor lamp type used in semiconductor steppers......
READ THE LINK I PROVIDED. The 3-chip / 3-color solution was common even as far back as when SONY made projection LCD sets......Minimum of 20 years ago....and I know longer.......And sets were 720p,
The OTHER solution was brought to you by Texas Instruments and used a SINGLE light source and 'mirrors' on a chip along with the vulnerable COLOR WHEEL so mirrors reflect (for example) RED from the image at the same
time as the RED slice of the color wheel is in place.....And so on. To improve black levels and contrast? ONE slice of the color wheel is black / opaque.....
Problem here was color fringing effects for some viewers. And the VIAS.....the space between cells was HUGE. And could easily be seen upon close screen inspection. I HATED it. The SONY SXRD chips (LoCos = Liquid Crystal On Silicon)
was the premium technology of the time and still is amazing today.....after what I hope are improvments to longevity......20,000 laser lifetime SHOULD be at least 8 projector lamps.....or even more?
I see many others STILL use the 3-chip LCD (transmissive, not reflective) technology common at the START of rear projection TVs.......
One tech that HASN'T been brought forward is what Mitsubishi used in the form of 3 CRT Projectors (again? RGB) with mirrors and combining optics......And ran warm......I think it was KLOSS who brought us the NOVABEAM which had some
problems and never got FULL Traction in the market. Besides? The boys a Mitsubishi made a better product which could actually be viewed in a room brighter than a CAVE......
And for KEITH? I'm not certain that a broad spectrum laser device is possible.....or has been made. Lasers are typically single wavelength devices, but I suspect that doping of the crystal may produce a wider bandwidth.....If guessing? I'd say
400nm to 700nm which is mostly visible..... I don't know how WIDE a bandwidth a laser can produce. I doubt 'white' light......but stand to be corrected.....But the wavelenths I list are from very blue/UV to very red/IR.....
There are UV lasers and I remember hearing abut X-Ray Lasers...but don't know how that worked out....