|Model:||Halospot 70 50W 12V. 41990 FL BA15d 24°|
|Application:||Specialist - Directional/display lighting|
|Bulb/Tube material:||Quartz lamp, aluminium reflector|
|Peak output wavelength:||N/A - Broadband emission|
|Total light output:||?|
|Rated lifetime:||2000 Hours|
|Value (now):||£8.44 (Compatible lamps available from BLT Direct)|
|Place of manufacture:||Germany|
|Date of manufacture:||Unknown - Code i768 present on lamp crown.|
|Notes:||The market for display lighting
is a hugely competitive one. Companies are continually
battling to provide brighter, more tightly controlled beams of more
uniform colour, and of course higher energy efficiencies.
While this does mean that it's a lighting field where progress tends to
be somewhat ahead of general lighting (hence the relatively commonplace
use of compact metal halide and WhiteSON lamps), it does mean that
technologies have an annoying tendency to become obsolete
quickly. These lamps are now quite rare, as compact quartz
halogen lamps with external dichroic reflectors have become far cheaper
alternatives - offering an added advantage of a (relatively!) cool beam.
This Osram product is a smart unit. A complete unit consisting of a 12V quartz halogen incandescent lamp, a solid aluminium reflector, a glare shield and a BA15d bayonet cap. All in a box, ready for service. The complete optical system and lamp unit means that with every lamp change, a perfectly aligned beam is maintained, and a new, clean reflector is fitted. Unfortunately, this convenience comes at a cost. The Halospot lamps were and still are very expensive when compared with other systems using an open reflector and a replaceable lamp. Even in bulk, I imagine these lamps probably run to £5 apiece, whereas a cheap capsule style 12V halogen lamp can be snapped up for well less than a pound. If you're running display lights 24 hours a day, you don't need me to tell you that over a year, that's a considerable difference.
The glare shield, axial filament and specially designed reflector produce a perfect beam (though I have not yet powered this example up, as I need to track down a suitable cap, know I have one somewhere!), which is devoid of the off-axis glare common to open lamp systems. Unfortunately, this highly concentrated beam contains not only all the light produced by the lamp, but all of the heat. The reflector, being aluminum, reflects heat just as well as it does light. Meaning that at anything less than long range, these lamps really are only suitable for lighting of items which will not be bothered by (considerable) heat. This is a problem not encountered by lamps using dichroic reflector, where the vast majority of the heat is dissipated out to the rear of the lamp.
Once these lamps were highly popular for display lighting, but since then, dichroic reflectors and cheap halogen lamps have come and stolen its place, which is in turn being slowly advanced on by the ever more accessible compact HID formats. Now however, this one forms an interesting part of my collection.
|Click Thumbnails for full size images.|
Lamp added to the Virtual Display Shelf on Thursday 28th August 2006 at 20:21.
References: None. I'd have loved a datasheet if I could have found one though!
Acknowledgements: Many thanks to the website user who kindly donated this lamp for display!