The angel eyes (or corona rings as BMW calls them) are a very distinguishable feature on the 21st century BMWs. Angel eyes are simply a fiber optic that encircles the headlight projector or reflector housing that is powered by a light at the beginning of the system. This revolutionary type of light styling was unheard of at the time and completely changed the game for the better. While these lights were originally used as running lights at night with the headlights, these became the standard daytime running lights on the newer BMW models. Not only do these corona rings serve a functional purpose, they are also visually appealing and give BMW vehicles their unmistakable appearance.
Angel eyes were first introduced on the BMW 5-series platform starting with the E39 in 2001. The first variants were not that bright when compared to the standards of today, but when they were first introduced, it was an amazing feat. The original lights were powered by an incandescent halogen bulb. Because of the E39's success, BMW began to include their angel eyes on all their newer BMW models; this includes the E82/E87 1-Series, E90/E91/E92/E93 3-Series, E60/F10 5-Series, E63/E64/F12/F13 6-Series, E38/E65/E66/E67/E68/F01/F02 7-Series, and much more. The original function of the angel eyes were used as parking running lights or city lights so they were only on when the headlights were on at night. However, beginning after the LCI face lift of many of the BMW models, the rings were standard daytime running lights as well.
The original method of light production was using an incandescent filament halogen bulb, but on the newest BMW 3-series models, the corona rings are lit up using LED lights instead. Light emitting diodes (LEDs) are noticeably brighter than their incandescent counterparts. They are also much more reliable and can potentially outlast the car in terms of operating usage. Brighter lights equates to increased safety because it allows other drivers on the road to see you more easily during less than pleasant weather and lighting conditions. LED angel eyes are also better at producing fewer emissions thanks to its low power consumption so it makes a greener technology as well as being bright. As lighting technology advances, BMW may even begin to use laser technology to light up the rings for brighter, but for now these are the current and latest trend in automotive lighting.
It has only been 12 years since the introduction of the BMW corona rings, but advancements have been made within that time span and it still continues today. Technology in general has been growing at an exponential rate and has no signs of slowing down in the future so only time will tell what the newest lighting technology will be. BMW definitely found their trademark look in these corona rings and it has definitely stuck with them because when you imagine a BMW driving towards you, all you see are those infamous light rings.