Fluorouscent lamp for Overhead projector

[[email protected]]

Hi,

Sorry for a stupid question.

I was looking at the LCD+OHP DIY projects and was wondering why don't
OHPs use fluoroscent lamps to maintain lower temperatures? Don't they
make FL lamps in the 3200-4000 lumen range or are they much more
expensive than incandescent lamps in that lumen range?
Thanks,

Siddhartha

 

[Rich Grise]

Hi,

Sorry for a stupid question.

I was looking at the LCD+OHP DIY projects and was wondering why don't
OHPs use fluoroscent lamps to maintain lower temperatures? Don't they
make FL lamps in the 3200-4000 lumen range or are they much more
expensive than incandescent lamps in that lumen range?
Thanks,

Siddhartha

Hi, Sid.

It's because fluorescents give a diffused light. This is good for a
lightbox, where you're the only one to look at it, but for projecting the
same transparency, it's much more efficient to collimate a point source
and let the screen do the diffusing.

Hope this Helps!
Rich

 

[[email protected]]

Hi, Sid.

It's because fluorescents give a diffused light. This is good for a
lightbox, where you're the only one to look at it, but for projecting the
same transparency, it's much more efficient to collimate a point source
and let the screen do the diffusing.

Thanks Rich.

- Siddhartha

 

[Don Klipstein]

Sorry for a stupid question.

I was looking at the LCD+OHP DIY projects and was wondering why don't
OHPs use fluoroscent lamps to maintain lower temperatures? Don't they
make FL lamps in the 3200-4000 lumen range or are they much more
expensive than incandescent lamps in that lumen range?

Projectors require very compact, concentrated light sources. Halogen
lamps with filament temperature pushed to around 3300 K (with life
expectancy usually less than 100 hours) are "low end" for accomplishing
this task...

Fluorescent lamps that put out about 3,000 lumens (or a bit less) are
nearly 4 feet or roughly 1.2 meters long and 1-1.5 inches (2.5-3.8 cm) in
diameter - how much of their light will be utilized by a projector?

- Don Klipstein ([email protected])