It looks like packageless IC. Usually it is die and bond wires on the board covered with special epoxy to protect die. It is inexpensive way to build some easy electronic devices like watch. The epoxy has the same temperature expansion coefficient as board material and it prevent cracking.
Sorry for late reply. I'm not sure is packageless IC and I heard people said is special epoxy as RF-OM spoken. Sometime we can discover the same matter on the PCB board but is on some other module eg. LCD. From my attached picture, it look like custom-made PCB. Long time a go, I found this kind of board which is have similar special epoxy on the board. The board function is flashing 2 LED's, this board is fix inside the kid shoes. I wonder what's the black color epoxy for??
May i know this kind of special epoxy can we get from the market?
If using die and bond wires on the board method it will very costly and which manufacturer have to ready the mechince for this kind of small demand design? Normaly, die bond wires is for standard product like semiconductor.
what's the purpose of this board? Where does it come from?
Putting die on the board as packageless IC is the cheapest way and this is why it is in so wide usage for chip and short time usage products like kids shoes. If you want to find information on black epoxy check packageless IC assembly web sites or ask manufacturers.