by CalScot » Thu Feb 24, 2011 4:12 am
[quote="Karl"]
It's a bit technical to get into on a written forum, but I'll try. I've attached a photo (shot by a user on PhotoBucket named RadioFlyerCustoms) of a proper drive-on-the-right-side-of-the-road low beam pattern. The important aspects are:
- The top of the pattern illuminates the farthest part of the road, therefore it is also the brightest.
- The cutoff is asymmetrical, with the part of the beam that is more likely to cause glare (left side) being cut off at a lower angle.
You can imagine that a high beam projector simply throws a cone of light onto the road, but that's fine as high beams are still adjusted to have the brightest part of the beam (the center of the cone) illuminate the farthest bits of road in front of you. If instead you take a high beam and tilt it downward, so that as little light as possible shines above the beltline of neighboring cars, you will end up with a bright spot about 100ft in front of your car, with little useful illumination beyond that point.
If this is still confusing to you, I could try drawing some more diagrams, but that takes a lot of time.
[/quote]
Mmm..
Beam spread for a given diameter is a function of frequency if I am not too drunk...
Since we are not messing with the frequency of light, the smaller the diameter of a given light output source, the larger the beam spread yes?
Therefore, "smaller" diameter lights in effect are more likely to have larger beam divergences? Of course, the "focus" of the lens of a smaller diameter lens has a not been factored but diameter for diameter, a larger or wider beam has the ability to project farther.
Maybe I should have another Cab and give up the physics. I'm certainly way out my depth with Karl
[quote="Karl"]
It's a bit technical to get into on a written forum, but I'll try. I've attached a photo (shot by a user on PhotoBucket named RadioFlyerCustoms) of a proper drive-on-the-right-side-of-the-road low beam pattern. The important aspects are:
[list]
[*]The top of the pattern illuminates the farthest part of the road, therefore it is also the brightest.
[*]The cutoff is asymmetrical, with the part of the beam that is more likely to cause glare (left side) being cut off at a lower angle.[/list]
You can imagine that a high beam projector simply throws a cone of light onto the road, but that's fine as high beams are still adjusted to have the brightest part of the beam (the center of the cone) illuminate the farthest bits of road in front of you. If instead you take a high beam and tilt it downward, so that as little light as possible shines above the beltline of neighboring cars, you will end up with a bright spot about 100ft in front of your car, with little useful illumination beyond that point.
If this is still confusing to you, I could try drawing some more diagrams, but that takes a lot of time.
[/quote]
Mmm..
Beam spread for a given diameter is a function of frequency if I am not too drunk...
Since we are not messing with the frequency of light, the smaller the diameter of a given light output source, the larger the beam spread yes?
Therefore, "smaller" diameter lights in effect are more likely to have larger beam divergences? Of course, the "focus" of the lens of a smaller diameter lens has a not been factored but diameter for diameter, a larger or wider beam has the ability to project farther.
Maybe I should have another Cab and give up the physics. I'm certainly way out my depth with Karl ;D