Advice on Carley reflectors

Some of these questions have partially been answered yesterday during chat, nevertheless I do have some questions for these who are more experienced with the line of Carley Aluminum reflectors.

I am refering to this
page.
1. What is the difference between the parabolic and the elliptical reflector? Could it be that they mislabeled the pictures?
2. Am I correct that the parabolic reflector is solid AL while the elliptical one has only thin AL walls?
3. What is the difference between these two in terms of throw and spill?
4. Different textures for the reflector have been mentioned, what are these and how do the influence the beam pattern?

Thanks in advance,

Klaus. /ubbthreads/images/graemlins/help.gif

1. Parabolic are also known as collimating. That is, they collect the light from a point source (the filament) and reflect it into a roughly parallel beam of light (rays). This is an infinite focal distance condition. Elliptical are also known as focusing. They collect the light from a point source and reflect and refocus it to a focal point some finite distance from the center of the reflector. Thus, to make a superthrowing flashlight, use parabolic. To build an illumination system that focuses all the light output at a specific distance to illuminate an object, use elliptical.

2. Both P and E reflectors come in solid and thin/carved out. The solid ones have a straight channel for the bulb to protrude through. The carved out ones are carved out to allow the placement of a keyed set screw at the base of the reflector to allow one to clamp the bulb in place. Normally, a metallic bulb sleeve is placed around the bulb so the set screw can be tightened down without crushing the glass capsule.

3. E and P are for completely different applications. All normal flashlights (to my knowledge) use P. Medical illumination and industrial lighting are common users of E.

4. The reflectors come in 5 possible finishes.
a. raw - bare aluminum, machine polished. soft surface, easily damaged, lowest reflectivity.
b. coated, smooth aluminized - very high reflectivity, tough surface, bright
c. coated, light orange peel, aluminized - very high reflectivity, tough surface, slight light dispersion characteristics. Softens beam artifacts, widens the hotspot.
d. coated, medium orange peel, aluminized - very high reflectivity, tough surface, moderate-high light dispersion characteristics. Softens beam artifacts more, widens the hotspot.
e. coated, heavy orange peel, aluminized - very high reflectivity, tough surface, stronger light dispersion characteristics. Softens beam artifacts, widens the hotspot. In practice, quite similar to medium.

The beam pattern is determined more by the filament and the reflector geometry than the coating. The coating/texturizing acts as a dispersing/diffusing field much light WriteRight, Acrylite, LDF, sand blasting, acid etching, Krylon, bead blasting, etc.

Wilkey

Thanks a lot, Wilkey. That was all I needed to know. /ubbthreads/images/graemlins/wink.gif

You're welcome Klaus.

Wilkey