51   Lanterns/Fixtures / Modern / Re: High lumen LED light fixtures that come with replaceable corn cob lamps?  on: November 21, 2024, 06:31:41 AM 
Started by WorldwideHIDCollectorUSA - Last post by Cole D.
I don’t think I have a picture of it in my gallery yet.
 52   General / Off-Topic / Re: Strange messages on store intercoms  on: November 21, 2024, 02:31:25 AM 
Started by Cole D. - Last post by Baked bagel 11
@Cole D.- It annoys me too that they play Christmas music from like November 1 to January 1.
 53   Lanterns/Fixtures / Vintage & Antique / Re: Joslyn help  on: November 21, 2024, 02:29:02 AM 
Started by Baked bagel 11 - Last post by Baked bagel 11
From today to the third of December, it is meant to arrive!
 54   Lanterns/Fixtures / Modern / Re: High lumen LED light fixtures that come with replaceable corn cob lamps?  on: November 21, 2024, 02:28:18 AM 
Started by WorldwideHIDCollectorUSA - Last post by Baked bagel 11
@Cole D.- Do you have a picture of that?
 55   Lanterns/Fixtures / Modern / Re: LED area light with latch on optic  on: November 21, 2024, 02:27:40 AM 
Started by Cole D. - Last post by Baked bagel 11
When was the Hubbell one made?
 58   Lanterns/Fixtures / Modern / Re: LED area light with latch on optic  on: November 20, 2024, 08:01:49 PM 
Started by Cole D. - Last post by Cole D.
Oh yes, I remember that one.
 59   Lamps / Modern / Re: Why do some PAR38 reflector lamps have a hexagon on the front  on: November 20, 2024, 05:36:18 PM 
Started by WorldwideHIDCollectorUSA - Last post by James
I believe this has to do with trying to attain a more symmetrical beam profile.  One of the first such designs was introduced and patented by Tungsram, which added two linear lenses moulded into the front.  They were positioned parallel to the CC-6 horizontal filament so as to broaden its beam in only one plane.  To improve efficacy by providing less scattering of light that in any case travels from the filament directly through the centre of the lens, they eliminated the miniature lenticules from that area and replaced it with a stippled structure.  See for instance US Patent 4,651,261 of 1985, https://depatisnet.dpma.de/DepatisNet/depatisnet?action=pdf&docid=US000004651261A&xxxfull=1

I suspect the only reason that ended up hexagonally shaped was because that is the natural close-packing structure of the small lenticules over the surface.  If they had tried to make a circular hole, it would not have had such a regular edge profile and would look a bit unprofessional.

An almost identical design then was then applied on German Osram PAR38 lamps.

Around the same time Philips moulded a full hexagon into the front lens of its PAR38 spot beam lamps, with six radial lines from each corner of the polygon.  I have not found a patent for that but suspect it may have been an improvement over the Tungsram/Osram designs.

It would be interesting to study some older PAR38 lamps to see when was the first origin of the hexagonally shaped area at the centre without lenticules - I think that was a much older invention.
 60   Lanterns/Fixtures / Vintage & Antique / Re: What configuration did these signals have?  on: November 20, 2024, 04:03:36 PM 
Started by Milwaukeeman2003 - Last post by Milwaukeeman2003
My best guess would be, from top to bottom, two reds, one yellow and green, and a walk indication.
Pages: < Previous Next > 1 ... 4 5 [6] 7 8 ... 10
© 2005-2024 Lighting-Gallery.net | SMF 2.0.19 | SMF © 2021, Simple Machines | Terms and Policies