Probably the world´s smallest SMT LED with a package size of 0.6x0.3x0.2 mm is so small that it can be used to create various symbols, pictograms and displays.
With the advent of small SMT LEDs on the market, let’s say in packages of „0805“ and smaller, majority of designers probably came to the point, that “such a small LED already fits everywhere”. It´s probably true for common application but if we, for example, want to backlight a small switch or to uniformly backlight some area, it´s usually better to use several smaller LEDs.
Similarly, for various “embedded“ systems with high demands for PCB density it´s usually advantageous to use the smallest possible LED, even though if serving for example only for a simple indication of some status. LEDs in 0603 and 0402 packages can be included in this category of say “super small LEDs”.
It´s worth mentioning that we talk about “imperial“ SMT packages sizes, which are relatively more frequently used than metric marking. That means that 0805 (imperial) = 2012 (metric) = 2.0x1.25mm or 0402 (imperial) = 1005 (metric) = 1.0x0.5mm and similar.
Kingbright marks their LEDs in metric code, that´s why for example KP 1608 series = “0603“ (imperial) and KPG-0603= “0201“ (imperial).
Namely KPG-0603 (0.6x0.3x0.2mm, 0201 imperial) represents currently the smallest LED from Kingbright and probably one of the smallest in the world. We can say that it´s so small that if it falls down on the floor, you almost certainly won´t find it anymore :-).
If we take aside various applications with ultra high components density, where every squared mm is precious, here a field for creating your own characters/symbols/pictograms or even the whole miniature displays opens. Price of one LED is reasonable and so even a big array (matrix) made of these LEDs is cost-effective – especially in comparison with a custom-modified display, which is not always cost-acceptable at small and mid-size production batches. Naturally, the great advantage is the fact that there are practically no limitations as for the shape and size of the active area when creating various symbols and miniature displays. Attached pictures may be a small inspiration.
Perhaps the only disadvantage of that small package is that soldering pads are already on the bottom side, thus the KPG-0603 is solderable only by reflow in a solder paste. Naturally, for development purposes it´s still possible to make it manually – by means of a hot air soldering station (ideally in combination with a PCB preheat plate) and a solder paste.