LED Makers' Old Paper Catalogs Research/Scan Help Wanted

[SeanB]

Translucent PCB is very easy, you just have a single layer of GRP mat, copper and no silkscreen and no soldermask. The single layer will have to be a whole sheet of board, so the manufacturer will charge you for it ( and it would be best to cover the whole board with copies of the track, so you can select those that work and have spares) but it is just the single inner layer of a multilayer stack, so is off the shelf.

You could even do it at home provided you have a milling machine ( and a carbide end mill you are going to destroy) and wet mill the finished single side board down to the right thickness. You probably will want to stick the board down to a acrylic sheet before though, so it has some support when you are milling. Acrylic will be part of the finished unit in any case, so all you have to do is back drill the LED solder points after thinning and solder the leads in, then fill with acrylic resin after cleaning and testing.

You can see in the OP that they were mounted in a clear acrylic sheet in press fit holes, then hand soldered with probably 28SWG enamelled wire, which was then potted with the whole unit.

[amyk]

Are you sure the dimensions are exactly 7mm x 14mm? Kingbright has 7.5 x 14 ones.

Do they look like the photo of Version 1 in post #1? No, they don't.

I'm saying that if you're looking for 7x14, you may be looking for the wrong size. The fact that they make a 7.5x14 size suggests that they might've made them in the style you're looking for.

[Scotophor]

(W)ith casting, and a sensible jig you can do dozens at once, no further work required.

Yes, and I've worked out the jig design already and bought the bits to make it from. Now I'm taking a couple of classes at my local makerspace to learn to use a milling machine and perhaps some of the other machines there, so I can make master pattern models from which to pour the silicone mold.

There are several reasons why I don't want to use the actual LEDs as pattern models. Firstly, they have a slight draft angle so that when several are stacked up side-by-side (like the five green ones at the lower left of the prop), they don't want to fit together tightly and straight at the same time; they describe a shallow curve. I'm not sure how the prop makers dealt with that issue. I suspect that they had to "square up" several of the LEDs on a sander before assembly. I'll start with pattern models that are already "square". Secondly, with the materials I'll be using, silicone shrinks 1-2% when making a mold, then the resin shrinks a further 1-2% when it's cast. So, I'll start by making pattern models about 3% oversized.

Have you considered going someplace like Shenzen, and seeing if you can find a factory to make you a few hundred custom LEDs?

I haven't actually tried, but as I understand it LED manufacturers generally won't even give you the time of day for less than 10,000 pieces (or the equivalent cost thereof). I believe the market for replicas of this prop is not quite that big, at the price I would have to get.

[Scotophor]

You can see in the OP that they were mounted in a clear acrylic sheet in press fit holes, then hand soldered with probably 28SWG enamelled wire, which was then potted with the whole unit.

Where can you see all that? As I understand it, the basic chassis of the prop is a milled-out block of clear acrylic with openings for battery and circuit boards, and channels for wiring. LEDs are glued  in clusters to the top of the main block, straddling the wiring channels. Top and bottom covers are assembled from tiles of various colors cut from 1/8 and a few 1/4 inch thick acrylic sheets, shaped to fit around and between the LED clusters. The tiles are mostly glued together edge-to-edge (another reason the props were fragile). There are a few portions of the covers where LEDs and perhaps some colored tiles are laminated onto 1/16 inch thick clear acrylic, but I'm fairly certain that the entire covers were not made that way. Small screws hold the covers on. Nothing is "potted".

[Scotophor]

Are you sure the dimensions are exactly 7mm x 14mm? Kingbright has 7.5 x 14 ones.

Do they look like the photo of Version 1 in post #1? No, they don't.

I'm saying that if you're looking for 7x14, you may be looking for the wrong size. The fact that they make a 7.5x14 size suggests that they might've made them in the style you're looking for.

To answer your question, yes the examples I have are exactly 14.0 mm x 7.0 mm within a reasonable tolerance, roughly +/- 0.05 mm. I imagine the spec'd tolerance was probably looser than that but probably not as loose as +/- 0.5 mm.

More catalog rejects:
AEG Telefunken Optoelectronic Devices Data Book, 1981/82
Ferranti Semiconductors Optoelectronic Devices, 1981
General Electric Semiconductor Data Handbook, 1977
Hewlett-Packard Optoelectronics Designers Catalogs, 1986, 1988-1989, 1991-1992, 1993, 1996
Motorola Optoelectronic Data Book, 1981-82 (no LEDs)
Siemens Optoelectronics Semiconductors Data Book, 1975/76
Toshiba Optoelectronic Semiconductors, 1984