An ERJ-190 Captain reported his windshield cracked after window heat failure produced a small fire from a presumed short. An emergency was declared and a safe landing ensued.

Narrative

While cruising at 15;000 FT at 300 KTS we heard a loud 'bang' noise. Looked up and the Captain's windscreen had cracks throughout the whole pane. A small electrical fire could be seen in the lower left hand side of the window where the wires for window heat had obviously shorted out. I immediately pulled the power back to idle to slow the aircraft and simultaneously told the First Officer to call ATC and declare an emergency; which he promptly did. I then told him to get the QRH and look up the EICAS message we had for '#1 Window Heater Fail;' which he did. We also requested a clearance down to 4;000 FT with a heading for direct to the airport; which again was granted by ATC. After approximately a 10-15 minutes flight from the time the window cracked; we successfully landed from a visual approach and taxied to gate with no further problems. The window failed either because of a bird strike (which I don't think it was) or the window; for unknown reason; failed. I felt the inside of the window and it was smooth; so the failure was either on the outside and inner panes; or one or the other of the two.