Sourcing Odd Parts LEP's (laser Exciting Phosphor) - Page 1
Forum section: electronics / beginners

author: DarkMode
author_rank: Contributor
timestamp: July 03, 2023, 10:14:02 am
content: Out of curiosity, I had come across this technology from a Survival Facebook group posting.I've been searching the Net for the unit and only found complete flashlights.This is the same issue I've had trying to search for COBs / High Powered Leds for a safety sign (in design).Where are the nooks and crannies?

author: tggzzz
author_rank: Super Contributor
timestamp: July 03, 2023, 11:05:05 am
content: Quote from: DarkMode on July 03, 2023, 10:14:02 amThe method of producing light is the same as in all white LED lights: blue light is downconverted to white light by the phosphor.From what I can see, it appears the claims are that the geometry of a LEP device allows a less diverging beam than with LEDs. I don't understand why that isnecessarilythe case.But more importantly, why would you want a safety sign that emits light only in a narrow direction? Surely you want a safety sign to be easily seen fromallangles?

author: tggzzz
author_rank: Super Contributor
timestamp: July 03, 2023, 05:27:00 pm
content: Quote from: DarkMode on July 03, 2023, 12:01:29 pmHm. So what, exactly, is the half-angle from which your signs must be visible and need not be visible?QuoteSo what?You ask about "excited phosphor" devices where blue light (from a laser) excites a phosphor. Thephotons emitted from the laser are not visible; only the photons emitted from the phosphor are visible.Now, what is the "mono-frequency" and "in phase" of the photons emitted from the phosphor?How do you make the phosphor emit the photons in only a narrow beam? Hint: you can't.If "mono-frequency" and "in phase" photons really are desirable, then your best choice is to use the laser without a phosphor.QuoteThat's a response I would expect from a troll.BTW: the "Quote" button is there for a purpose.

author: Marco
author_rank: Super Contributor
timestamp: July 03, 2023, 05:57:17 pm
content: Quote from: tggzzz on July 03, 2023, 11:05:05 amSmaller spot size. Sure, a standard convex lens can't capture all the light from that spot directly in a collimated beam, but what it can capture diverges less. You capture what you can and spread the rest out with non imaging optics.PS. not saying this is what the OP intended, but that's why the flashlight nerds want it.

author: switchabl
author_rank: Frequent Contributor
timestamp: July 03, 2023, 08:13:21 pm
content: A lot of designs are probably custom, along with matching optics. But Kyocera actually offers a fully integrated chip now (https://www.kyocera-sldlaser.com/). It's available from Digikey, Mouser etc...

author: DarkMode
author_rank: Contributor
timestamp: July 04, 2023, 08:25:40 am
content: Brillant, thank you

author: tggzzz
author_rank: Super Contributor
timestamp: July 04, 2023, 08:31:04 am
content: Quote from: DarkMode on July 04, 2023, 08:21:31 amAny response to my questions about what mono-frequency and phase you expect phosphors to emit, and the directionality in which they emit photons?

author: tggzzz
author_rank: Super Contributor
timestamp: July 04, 2023, 02:53:32 pm
content: Quote from: DarkMode on July 04, 2023, 02:23:22 pmYour initial response was belligerent, and I responded with the same tone. You don't appreciate it? Well, neither do I."Physician, heal thyself."

author: switchabl
author_rank: Frequent Contributor
timestamp: July 04, 2023, 04:13:53 pm
content: Ignoring the bickering for a moment, and to avoid (potentially expensive) disappointment for the OP or others who come across this topic, let me state this explicitly: these sources employ a laser to activate the phosphor but the light they emit has basically nothing in common with that from a laser. It is neither monochromatic (clearly, since it is "white"), coherent (spatially or temporally) nor directed (emission is approximately Lambertian).The unique selling point is that they pack a high power in a small area (the 1000lm Kyocera has a 0.5mm diameter spot). As Marco said, it is the small spot size that allows you to create a pretty well-collimated (=low divergence) beam using a single convex lens which is desirable for applications like projectors, microscopy and search lights.

author: tggzzz
author_rank: Super Contributor
timestamp: July 04, 2023, 06:33:59 pm
content: Quote from: switchabl on July 04, 2023, 04:13:53 pmPrecisely.Another issuemightbe the longevity of the phosphor materials and the (epoxy?) carrier containing them. The whole point of their design is to have a very high energy density.Presumably the OP's sign will be illuminated for a long time. IIRC the Kyocera datasheet doesn't mention lifetime.

author: switchabl
author_rank: Frequent Contributor
timestamp: July 04, 2023, 09:04:56 pm
content: AFAIK Kyocera claim 10.000h @70% for the 500lm. That is in line with what I have seen for discrete solutions as well. Like with LEDs, I believe lifetime is strongly affected by temperature.It is a very interesting product (within a specific niche).

author: tggzzz
author_rank: Super Contributor
timestamp: July 04, 2023, 09:15:04 pm
content: Quote from: switchabl on July 04, 2023, 09:04:56 pmI only glanced at the 1000lm, so perhaps there isn't a conflict there. There's the old rule of thumb never to use the smallest or largest parts in a range, since those are likely to be on the edge of manufacturability.itisan intriguing component. Equally interesting are what the niche actuallyis, and the niche's limits.

author: DarkMode
author_rank: Contributor
timestamp: July 05, 2023, 12:44:03 am
content: Great Information, thanks

author: tggzzz
author_rank: Super Contributor
timestamp: July 05, 2023, 06:54:53 am
content: Quote from: DarkMode on July 05, 2023, 12:49:06 amIf you think that's what "belligerent" means, I suggest you consult a dictionary, e.g.https://www.merriam-webster.com/dictionary/belligerenthttps://dictionary.cambridge.org/dictionary/english/belligerent