Hi, I work as a product designer an am trying copy a detail that Bose have on their head phones. Essentially they have what looks like flat black ABS plastic back light with some LEDS. Next to the LED is a printed symbol (Pad printing I think).

How do they create this clever effect with the LEDs?

At first I thought the plastic might have been translucent and that the black coating had been printed on the the outside. However, as you can probably see in the image, I tried scratching away on the top black surface to find that it looks like this whole chunk of material is black ABS.

So how do they get the light through?

• Is the wall thickness where the LEDs are super thin? But I tried poking the left one and it seems pretty tough.
• Is there a hole all the way through the black ABS where the LEDs are and they insert some very tight fitting light guides/pipes?

Any thoughts/comments would be really appreciated. Thanks.
Greg