You mean the end of the bulb? That's irrelevant in light throw because the light needs to be emitted sideways for the reflector to bounce the beam and cast it out. The bulb design could have incorporated a LED at the end, but it would only create glare for oncoming traffic and not aid in light throw much at all. Remember, any type of light (halogen, HID, or LED) can't throw its beam well without a reflector. Without a reflector, they work like candles and emit undirected light everywhere.~tc~ wrote:There is no reason to believe the area behind the SMD is what they are talking about - more likely the "end cap" which normally has at least some light output.
This is also how lights and lasers differ and the reason why laser headlights are being developed as the next generation of headlights. Laser headlights would eliminate the need for reflectors and can accurately cast light only where needed and even be adaptive, changing light throw based on conditions such as oncoming traffic.
Given how light is reflected inside a headlight, the very SMD stem is what they are talking about and not the end cap. The end cap barely matters.
Keep in mind that halogens have this same issue and that's why many bulbs even have their ends painted and some headlights/fog lights even have bulb end caps. Both of the pictures below clearly demonstrate what I'm talking about in both the bulb and the headlight. This is for reducing glare.