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Bottom-firing surface mount LED?

Hi all,

I'm searching for tiny bottom-firing LEDs, preferably surface mount.

The LEDs are indicators for a multiport connector. The LEDs will fire through the PCB into some light pipes integrated into (and flush with the bottom of) the connector.

I'm after the following:

- The LEDs have to be tiny, as the lightpipes are close to each other and I want to to minimise bleed.

- Multicolour - at least Red and Green.

The closest I've come is this series from Everlight:

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but they're too big.

This part is representative of the sort of connector I'm using:

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The light pipe "entry ports" are visible in the picture as the eight shiny dark rectangles close to the electrical pins.

Any ideas?

Other information:

- About 6mm clearance below the board.

- to be placed by regular P&P equipment.

- preferably no special lead forming. I did this for some HP LEDs in the early '90s and (whilst it met my goals at the time) I would not like to do it again.

- not particularly cost sensitive (low volume)

- All the usual compliance (ROHS, etc.)

- I don't have a good idea of the Luminous Intensity requirement yet. I don't know how well the LED will couple to the lightpipe, nor do I know the lightpipe loss. Then there's the whole subjective brightness thing. I will probably end up doing this part empirically.

Thanks, Allan

Reply to
Allan Herriman
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Can you buy connectors with built-in LEDs?

Reply to
John Larkin

I haven't found any. I've looked at the usual suspects: Molex, TE, etc.

Other approaches would be to use connectors without lightpipes and add either a mimic panel somewhere else (but there's no room on the panel) or lightpipes *outside* the connector.

I've used clip-on external lightpipes for single height connectors in products before with great success, but I haven't found any for double height connectors like these. Single height example:

formatting link

Regards, Allan

Reply to
Allan Herriman

Did you look in DigiKey? I see about 100 bottom-firing ("surface mount bottom-entry") LEDs there, about 50 of which are in stock. I've used KingBright (my favorites because they'll easily take RoHS soldering), LiteOn, and Osrams in the past. I don't see the ones I've used, on DigiKey though.

Reply to
krw

Here are some that we use...

459-4500 CON RJ RJ45 PCB 8X SHIELDED TYCO AMP 555153-1 0.83 285

459-4501 CON RJ RJ45 PCB 8X MOUSER 154-7641PCB 0.70 4

459-4502 CON RJ RJ45 CRIMP 8X FOR C285 MOUSER 154-7641 0.54 20

459-4503 CON RJ RJ45 PCB 8X RA W/ LIGHT PIPES MOLEX

43860-0010-TR80 2.77 9

459-4504 CON RJ RJ45 PCB 8X RA KEY DIGIKEY A9035-ND 0.00 0

459-4505 CON RJ RJ45 PCB 8X KEY DIGIKEY H9084 3.08 32

459-4506 CON RJ RJ45 QUAD 8X SHIELDED + LEDS AMPHENOL RJSAE-5381-04 5.06 54

459-4507 CON RJ RJ45 PCB 8X VERT SHIELD DIGIKEY 609-1072-ND 1.00 13

459-4550 CON RJ RJ45 PCB 1X ETHERNET MAG UP BEL SI-46001-F 2.35 14

459-4551 CON RJ RJ45 PCB 1X ETHERNET MAG RA SMT WURTH 7498011121 6.62 56
Reply to
John Larkin

You _want_ your display to be useless to around 8% of the male population? Why?

formatting link 

--
Tim Wescott 
Control system and signal processing consulting 
www.wescottdesign.com
Reply to
Tim Wescott

I don't know how successful I'll be plugging an SFP+ module into an 8P8C modular jack ("RJ45").

:)

It seems that the manufacturers of ganged SFP+ sockets all decided that they didn't want LEDs in the connectors and put in lightpipes instead. I like that - I get to choose the colours and brightness (and not be stuck with a combination of insidious yellow and feeble green with 1970s LED efficiencies).

Regards, Allan

Reply to
Allan Herriman

What LED colours would you recommend that allow the following?

- two colours that are easy to distinguish by everyone.

- one colour obviously represents "working"

- the other obviously colour represents "not working"

- are supported in easily obtainable, cheap LEDs

- are also available in RJ45 LEDs

BTW, I don't want Red and Green; Marketing does. I'm not allowed to innovate past the spec which was based on the spec of an earlier product. Recurse that all the way back to before there were other colours of LEDs.

A few years back I designed RGB LEDs into a similar application. To this day, only the R and G segments are turned on by our application. The B segment only gets turned on during "lamp test".

(I'm not bitter.)

Allan

Reply to
Allan Herriman

Thanks for those manufacturers. I think I had tried all of them, but I'll look again. I tried Digikey first. Actually, one of the links in the OP was to Digikey's website. :) All the LEDs there were too large unfortunately.

I'm starting to think that what I want to do isn't possible, and I'll have to forgo the bicolour requirement.

Regards, Allan

Reply to
Allan Herriman

I can answer that one myself from the wikipedia link you provided:

"... red-blue and yellow-blue color combinations are generally safe."

I can't get that in connectors with built-in LEDs, but I can synthesise those colours if I use external RGB LEDs ... which I can't get in packages small enough to fire into my lightpipes for the connectors I want to use for this project. Dang.

Regards, Allan

Reply to
Allan Herriman

Oh, that's the optical module thing; sorry.

Reply to
John Larkin

I just used some 0603s. I had top and side-firing but I think they also had bottom in the series. I don't have the information handy, though. Smaller than 0603s, the options are limited.

Reply to
krw

Those are the most likely combinations, yes. There are some people who are totally color blind, but that's very rare.

When I can get away with it I just present designs with separate LEDs, so that you can tell what's what by position. But, that assumes I can get away with it.

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com
Reply to
Tim Wescott
[snip]

Well, this is embarrassing.

A co-worker found this document that describes how it's done:

formatting link

These connectors are designed to work with surface mount *top-firing* LEDs under the connector. In the picture I posted

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it really looks like the lightpipes are flush with the bottom. However, there is actually a small gap, and the lightpipes are flexible, allowing a LED of up to 0.8mm thickness to be placed directly under the lightpipe. The lightpipe will touch the top of the LED, allowing good light transfer and low bleed.

We already have a suitable LED in our library. The subcontractor will even P&P them with the correct orientation occasionally.

BTW, it's a press-fit connector. It's fitted after the LEDs have been soldered.

Thanks to all who responded.

Regards, Allan

Reply to
Allan Herriman

I haven't read the wiki article, but I do not pass the red-geen color test. Therefore I'm one of the 8%. However, I don't have any trouble at all seeing red and green. I certainly would have no trouble with red vs. green leds. None at all. Go figure.

The eye doctor looked at me with a pitying expression, but I am not fooled.

I can see the most subtle shades of red and green in art works. For example, Cezanne uses a lot of red, green in his still lifes.

j
Reply to
haiticare2011

It's on page 1 of the data sheet. Notes item 4

--
Chisolm 
Republic of Texas
Reply to
Joe Chisolm

It's better to be embarrassed by finding a solution than have thrown your hands up in despair and not gotten anywhere, though!

--
Tim Wescott 
Control system and signal processing consulting 
www.wescottdesign.com
Reply to
Tim Wescott

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