On Sun, 8 Oct 2023 13:41:08 -0700, Don Y <blockedofcourse@foo.invalid> wrote:>On 10/8/2023 12:23 PM, legg wrote: >> On Sun, 8 Oct 2023 04:08:55 -0700, Don Y <blockedofcourse@foo.invalid> >> wrote: >> >>> I need to mount (many) RGB indicators at right angle >>> to the PCB (i.e., so the light travels parallel to the >>> plane of the PCB) >>> >>> The entire assembly needs to be *really* thin. >>> >>> Using SMT components, it seems like I'd have to use >>> lightpipes to bend the light (typically emitted normal >>> to the PCB). This will add to the thickness of the assembly >>> (board thickness + component + pipe) >>> >>> A better approach might be to use leaded components >>> mounted on their sides AT the edge of the PCB and >>> selecting them for smallest diameter possible (as >>> this would conceivably be the largest dimension in the >>> assembly's thickness). >>> >>> I'm looking for ~100K qty (LEDs) and can provide my own >>> drive electronics (I looked at the "RGB LEDs with integrated >>> drivers" and came up lacking). >>> >>> Another alternative might be SMT devices shining *through* >>> the PBC into pipes -- the thickness of the PCB offsetting >>> some of the required "height" of the pipe as it navigates >>> its bend) >>> >>> I can't think of any other alternatives... >> >> I've used top-firing leds under a square rod of lexan, >> machined along its length and painted white on the >> machined surface. > >Hmmm... I'd have thought a (molded, rounded) surface would give >the desired "reflection" (assuming compliant with refractive >index). I wonder what the absorption losses are in the paint?If you want to read led indicators over a wid viewing angle, you've got to diffuse the light somehow on the protruding portion. You can buy this type of package (or haul out the sandpaper). The assembly I've described is only useful if you look at it straight on ~ like any meter that performs the same function.> >> Viewed from the side, the eye sees the led projecting >> on the white angled surface. Avoids annoying LED brightness >> while still differentiating between adjacent indicators. >> >> Stick as many emitters as you want, side by side - just cut >> the lexan rod to length to cover the group. > >This still doesn't avoid the "assembly thickness" issue. >(crap, designing for "tiny" is *really* hard!)The 'emitting' surface here is the paint - you can make the mech height anything you want.> >Or, the added assembly step (to machine & add the light pipe). >I was hoping to buy a component with the light reoriented in >the plane I wanted... >So go ahead and buy something . . . no arm twisting here. . . but, frankly, led indicators are ridiculously bright and difficult to dim uniformly. RL
right angle RGB leds
Started by ●October 8, 2023
Reply by ●October 9, 20232023-10-09
Reply by ●October 9, 20232023-10-09
On Mon, 09 Oct 2023 10:35:46 -0400, legg <legg@nospam.magma.ca> wrote:>On Sun, 8 Oct 2023 13:41:08 -0700, Don Y <blockedofcourse@foo.invalid> >wrote: > >>On 10/8/2023 12:23 PM, legg wrote: >>> On Sun, 8 Oct 2023 04:08:55 -0700, Don Y <blockedofcourse@foo.invalid> >>> wrote: >>> >>>> I need to mount (many) RGB indicators at right angle >>>> to the PCB (i.e., so the light travels parallel to the >>>> plane of the PCB) >>>> >>>> The entire assembly needs to be *really* thin. >>>> >>>> Using SMT components, it seems like I'd have to use >>>> lightpipes to bend the light (typically emitted normal >>>> to the PCB). This will add to the thickness of the assembly >>>> (board thickness + component + pipe) >>>> >>>> A better approach might be to use leaded components >>>> mounted on their sides AT the edge of the PCB and >>>> selecting them for smallest diameter possible (as >>>> this would conceivably be the largest dimension in the >>>> assembly's thickness). >>>> >>>> I'm looking for ~100K qty (LEDs) and can provide my own >>>> drive electronics (I looked at the "RGB LEDs with integrated >>>> drivers" and came up lacking). >>>> >>>> Another alternative might be SMT devices shining *through* >>>> the PBC into pipes -- the thickness of the PCB offsetting >>>> some of the required "height" of the pipe as it navigates >>>> its bend) >>>> >>>> I can't think of any other alternatives... >>> >>> I've used top-firing leds under a square rod of lexan, >>> machined along its length and painted white on the >>> machined surface. >> >>Hmmm... I'd have thought a (molded, rounded) surface would give >>the desired "reflection" (assuming compliant with refractive >>index). I wonder what the absorption losses are in the paint? > >If you want to read led indicators over a wid viewing angle, you've >got to diffuse the light somehow on the protruding portion. >You can buy this type of package (or haul out the sandpaper).Light pipes are in stock at Digikey. http://www.highlandtechnology.com/DSS/P900DS.shtml That has a row of side-firing LEDs on the main board and mushroom-shaped light pipes through the panel. Sometimes we use a polycarb sticker that has frosty windows, to do the same thing. http://www.highlandtechnology.com/DSS/P620DS.shtml> >The assembly I've described is only useful if you look at it >straight on ~ like any meter that performs the same function. >> >>> Viewed from the side, the eye sees the led projecting >>> on the white angled surface. Avoids annoying LED brightness >>> while still differentiating between adjacent indicators. >>> >>> Stick as many emitters as you want, side by side - just cut >>> the lexan rod to length to cover the group. >> >>This still doesn't avoid the "assembly thickness" issue. >>(crap, designing for "tiny" is *really* hard!) > >The 'emitting' surface here is the paint - you can make the >mech height anything you want. >> >>Or, the added assembly step (to machine & add the light pipe). >>I was hoping to buy a component with the light reoriented in >>the plane I wanted... >> >So go ahead and buy something . . . no arm twisting here. . . >but, frankly, led indicators are ridiculously bright and >difficult to dim uniformly.I have an idea: adjust the current electronically! I'll patent that!> >RL
Reply by ●October 9, 20232023-10-09
legg <legg@nospam.magma.ca> wrote:> So go ahead and buy something . . . no arm twisting here. . . > but, frankly, led indicators are ridiculously bright and > difficult to dim uniformly. > > RLWould constant current sources improve uniformity? If not, why not? -- MRM
Reply by ●October 9, 20232023-10-09
On 10/9/2023 7:35 AM, legg wrote:>>> I've used top-firing leds under a square rod of lexan, >>> machined along its length and painted white on the >>> machined surface. >> >> Hmmm... I'd have thought a (molded, rounded) surface would give >> the desired "reflection" (assuming compliant with refractive >> index). I wonder what the absorption losses are in the paint? > > If you want to read led indicators over a wid viewing angle, you've > got to diffuse the light somehow on the protruding portion. > You can buy this type of package (or haul out the sandpaper).Yes, but that's usually on the "exit surface". I'm talking about light "leaking" out of the "pipe" due to critical bend angles; i.e., a curved transition loses less light than an abrupt one (depends on material).> The assembly I've described is only useful if you look at it > straight on ~ like any meter that performs the same function. >> >>> Viewed from the side, the eye sees the led projecting >>> on the white angled surface. Avoids annoying LED brightness >>> while still differentiating between adjacent indicators. >>> >>> Stick as many emitters as you want, side by side - just cut >>> the lexan rod to length to cover the group. >> >> This still doesn't avoid the "assembly thickness" issue. >> (crap, designing for "tiny" is *really* hard!) > > The 'emitting' surface here is the paint - you can make the > mech height anything you want.Yes, but it is ADDED to the height of the LED (which may, in turn, be added to the "height" of the PCB). This is why I suggested down-firing LEDs with a pipe that can start its bend "within" the thickness of the PCB: VVV ==========\\\========== ---------- -------- (ugh! ASCII art won't cut it) I.e., the top (here, BACK) side of the LED is at the same point in space as if it was UP firing. But, instead of the pipe starting its turn ABOVE that point, the turn can be started "in" the thickness of the PCB so that the light is (eventually) emitted closer to the plane of the PCB. In effect, emulating a right-angle LED>> Or, the added assembly step (to machine & add the light pipe). >> I was hoping to buy a component with the light reoriented in >> the plane I wanted... > > So go ahead and buy something . . . no arm twisting here. . . > but, frankly, led indicators are ridiculously bright and > difficult to dim uniformly.The problem is finding something that fits the size constraints. So far, the "thinnest" assembly is the result of mounting a thru-hole LED on it's side AT the edge of the PCB (because you can absorb the thickness of the PCB in the calculation)
Reply by ●October 10, 20232023-10-10
tirsdag den 10. oktober 2023 kl. 00.05.14 UTC+2 skrev Don Y:> The problem is finding something that fits the size constraints. > So far, the "thinnest" assembly is the result of mounting a > thru-hole LED on it's side AT the edge of the PCB (because > you can absorb the thickness of the PCB in the calculation)only if you can find an extremely thin thru-hole LED, if you surface mount it it'll half the led + half the pin +solder will be above the pcb surface if mount it in castelatted "slots" it'll be half led - half pcb above the pcb surface and it'll be a manual process not something you'd want to do with 100s or 1000s
Reply by ●October 10, 20232023-10-10
On 09/10/2023 23:05, Don Y wrote: <snip>> The problem is finding something that fits the size constraints. > So far, the "thinnest" assembly is the result of mounting a > thru-hole LED on it's side AT the edge of the PCB (because > you can absorb the thickness of the PCB in the calculation)Well, vertical SM LEDs on their side on the PCB edge would be thinner - use plated through holes as the pads, and mill through the centres to leave half a hole at the PCB edge. I think they're called castellated holes. Easy to solder manually, not sure what a board shop would make of it. -- Cheers Clive
Reply by ●October 10, 20232023-10-10
On Mon, 9 Oct 2023 15:05:00 -0700, Don Y <blockedofcourse@foo.invalid> wrote:>On 10/9/2023 7:35 AM, legg wrote: >>>> I've used top-firing leds under a square rod of lexan, >>>> machined along its length and painted white on the >>>> machined surface. >>> >>> Hmmm... I'd have thought a (molded, rounded) surface would give >>> the desired "reflection" (assuming compliant with refractive >>> index). I wonder what the absorption losses are in the paint? >> >> If you want to read led indicators over a wid viewing angle, you've >> got to diffuse the light somehow on the protruding portion. >> You can buy this type of package (or haul out the sandpaper). > >Yes, but that's usually on the "exit surface". I'm talking >about light "leaking" out of the "pipe" due to critical >bend angles; i.e., a curved transition loses less light >than an abrupt one (depends on material). > >> The assembly I've described is only useful if you look at it >> straight on ~ like any meter that performs the same function. >>> >>>> Viewed from the side, the eye sees the led projecting >>>> on the white angled surface. Avoids annoying LED brightness >>>> while still differentiating between adjacent indicators. >>>> >>>> Stick as many emitters as you want, side by side - just cut >>>> the lexan rod to length to cover the group. >>> >>> This still doesn't avoid the "assembly thickness" issue. >>> (crap, designing for "tiny" is *really* hard!) >> >> The 'emitting' surface here is the paint - you can make the >> mech height anything you want. > >Yes, but it is ADDED to the height of the LED (which may, >in turn, be added to the "height" of the PCB). This is why >I suggested down-firing LEDs with a pipe that can start its >bend "within" the thickness of the PCB: > > VVV >==========\\\========== > ---------- > -------- > >(ugh! ASCII art won't cut it) > >I.e., the top (here, BACK) side of the LED is at the same point >in space as if it was UP firing. But, instead of the pipe starting >its turn ABOVE that point, the turn can be started "in" the thickness >of the PCB so that the light is (eventually) emitted closer to the >plane of the PCB. In effect, emulating a right-angle LED > >>> Or, the added assembly step (to machine & add the light pipe). >>> I was hoping to buy a component with the light reoriented in >>> the plane I wanted... >> >> So go ahead and buy something . . . no arm twisting here. . . >> but, frankly, led indicators are ridiculously bright and >> difficult to dim uniformly. > >The problem is finding something that fits the size constraints. >So far, the "thinnest" assembly is the result of mounting a >thru-hole LED on it's side AT the edge of the PCB (because >you can absorb the thickness of the PCB in the calculation) >You could put the surface-mount (1mm tall) LEDs on both sides of a thin PCB. Sandwich that with a stack of similar boards. That brickwalls the LEDs on about 2mm centers and needs half as many PCBs.
Reply by ●October 10, 20232023-10-10
On Mon, 9 Oct 2023 20:11:56 -0000 (UTC), Mike Monett VE3BTI <spamme@not.com> wrote:>legg <legg@nospam.magma.ca> wrote: > >> So go ahead and buy something . . . no arm twisting here. . . >> but, frankly, led indicators are ridiculously bright and >> difficult to dim uniformly. >> >> RL > >Would constant current sources improve uniformity? If not, why not?Differences between emitter intensity at low currents make uniform dimming of discrete emitters a pain in the ass. When 'bright', the difference isn't as obvious, because you don't want to look at them directly, anyways. If a uniform intensity is guaranteed at a specific current level for a 'graded' emitter, you can get predictable results by pwming their excitation. RL
Reply by ●October 10, 20232023-10-10
On Mon, 9 Oct 2023 15:05:00 -0700, Don Y <blockedofcourse@foo.invalid> wrote: <snip>>The problem is finding something that fits the size constraints. >So far, the "thinnest" assembly is the result of mounting a >thru-hole LED on it's side AT the edge of the PCB (because >you can absorb the thickness of the PCB in the calculation) >So, use the "thinnest" assy. "Thin" assys give me the XXXs. For XXX's sake, who needs them? My problem was a retrofit to use available space in a large filled body. It was applied to a captive board display that was already cheaply fabbed, in volume, for use in an exhorbitantly marked up consumer product who's tooling budget might have financed world XXXing peace. They 'stole' the concept for the next rev, rather than redesign. If you're designing from the ground up, you've only got yourself to blame. RL
Reply by ●October 10, 20232023-10-10
On 10/10/2023 10:06 AM, legg wrote:> On Mon, 9 Oct 2023 15:05:00 -0700, Don Y <blockedofcourse@foo.invalid> > wrote: > > <snip> > >> The problem is finding something that fits the size constraints. >> So far, the "thinnest" assembly is the result of mounting a >> thru-hole LED on it's side AT the edge of the PCB (because >> you can absorb the thickness of the PCB in the calculation) >> > So, use the "thinnest" assy. > > "Thin" assys give me the XXXs. For XXX's sake, who needs them?If you don't have the space (volume), then "thin" is the only solution. Imagine designing a cell phone with "conventional" components (they were called BAG phones).> My problem was a retrofit to use available space in a large > filled body. It was applied to a captive board display that > was already cheaply fabbed, in volume, for use in an > exhorbitantly marked up consumer product who's tooling > budget might have financed world XXXing peace. > > They 'stole' the concept for the next rev, rather than redesign. > > If you're designing from the ground up, you've only got yourself > to blame.Or, rather, the *market* you want to serve!
