You can mock this up with 2 of your chosen LED’s very quickly. You’re probably at a point where if you are close to being able to prototype this with some 3D printed parts, you would learn a lot through trial and error. The different thicknesses you have in place for the snap features will cause different light and dark spots and make it harder to make uniform. Since the outer lens will just be a diffuser, try to minimize or keep any mounting features uniform. You will lose that phenomenon and the outer lens would only be good for basic diffusion. Most lightpipes rely on total internal reflection, to keep light bouncing around inside the material to improve the uniformity. Because you have a pipe, plus the outside lens, you will lose a lot of light in the gap. 4 LED’s (two on upper and two on lower area of PCB) would give you a better distribution along the side, and you may be able to design some pipe features into the outer housing itself to better disperse the light.īased on what you’ve shown you will likely end up with a result that looks more like this: You may be better off shooting those LED’s to the sides, and illuminating the edge of the product. Typical tricks would be to try to move it as far away as possible, and pipe it towards the top, but the board means half your LED cone would be cut off by the PCB itself. Especially if your internal housing remains black, since that prevents the light from bleeding out to the housing.įrom the scale of your exploded diagram it looks like you have less than 1cm for your LED’s to illuminate, which means the spread of those LED’s will only form a lit area that is very narrow. As mentioned, creating a smooth uniform glow with limited LED space, a small number of LED’s and light across surfaces in 5+ directions is very challenging. My suggestion would be to design a more local lightpipe area that would still meet your need, and creating that outside housing as 2 pieces or a two shot part (opaque over clear). If the main housing is opaque, that type of light pipe would just give you some soft illumination on the top surface at best. If you want a better idea of the approach to use and can share a cross section of where your PCB is and where you want to illuminate its sometimes easier to sketch.Īgreed that trying to evenly light an area that large especially if it’s just a cover will be challenging (not impossible, but challenging!) Once you have a rough idea, then you can move to a 3D printed part (it may need to be hand polished) or a cast urethane part. I’ve done experiments using Keyshot raytracings to try and simulate some of the effects, but generally the renderings take forever and are still only so accurate. If the LEDs are at an angle or awkward position, then you would have to look at actually building a pipe to try and route the light up which is a bit more complex. If you can get the LEDs laid out on the board where they all consistently intersect with the surface you want to light up, then you likely don’t need any “pipe” features at all. You want the positioning of the LEDs to be enough where you have a slight overlap of each cone (since there is falloff from the center to the outside of the cone). If the LED is shining straight towards the surface that will be fairly easy. The easiest way to get a rough estimate of this working is to find the cone of your LED (ex 60 degrees) and model it into your CAD model so it’s shining out of the LED. It’s hard to tell the desired effect and complexity from the photo you posted, but in general good light dispersion requires - the right LED (with a cone that matches the intended illumination area), the right plastic to either diffuse the light (we used a lot of Lexan FXD materials for light pipes since they could be milky to diffuse light better), and the right distance from the PCB for the cone to spread to hit the intended area. There is optical analysis software that can do complex raytracing and calculate this, but we’ve always had an optical engineer who spent most of their days designing lenses for that level of complexity.
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