All the LEDs I've seen have been built into a lens. I believe they (and by they I mean the tiny bit of metal/semi-conductor that makes the light) are an inherently omnidirectional source, like an incandescent, but with large parts of the light blocked by the armature around the light-emitting spot. But they're packaged in an acrylic lens to focus the light, including the flat bottom to reflect backward-emitted light. However, you might be able to find packaging which provides a different shape lens; check with LED wholesalers? My brain is remembering one with a more flat front lens, for a wider-angle area of emitted light.
(no subject)