--- In [email protected], Bob Werre <[EMAIL PROTECTED]> wrote:
> Yes Ed, I have done a test in the last couple of nights using the
> surface mount LED mounted in a MV lens. My impression with the
> resistor provided, was that it was just a bit dim.
Using a lower value of reistor will make the LED brighter. Just be
careful not to exceed the LED's current rating.
> The problem with the surface
> mount unit is that it's like a bare bulb where the light is
> emitted in all directions.
That is true -- it is the nature of the beast. But is it really
a "problem"? Comments below.....
> The more typical larger bullet shaped unit focuses
> light, which better imitates the polished reflector in a steam era
> headlight.
One way to get a strong focusing effect is to use a bulb with an
MV lens. The trick is to find the "sweet spot" that maximizes the
focusing ability of the MV lens which has the properly shaped
parabolic reflective surface. Finding the sweet spot is not
intuitive. Y'gotta drill a small hole all the way through the center
of the MV lens just big enough for the bulb to fit. Then insert the
bulb from behind and make sure it can slide in/out to and fro
smoothly. Turn out the room lights, turn on the miniature bulb, and
move it back and forth in/out until the beam of light is perfect.
Then glue the bulb in place before it moves. Only one hitch, the
exact placement of the bulb depends largely on where the filament is
located within the glass envelope. Different bulbs are built
differently. With some bulbs, it is common to have the bulb actually
protrude a bit from the front surface of the MV lens. Those who do
this prefer the strong focusing effect and are willing to accept the
bulb's protrusion in order to get it. The bulb's protrusion is not
really noticeable from a normal viewing distance. I've never tried
this with an LED, but it might work same as for bulbs. Although the
SMT LED does not cast light backwards toward the reflector like a
bulb's filament does, the overall effect might be acceptable anyway.
Need to do some experimentation here. Perhaps someone else has
already tried this? Would be interesting to know. Any volunteer
researchers out there? Cheers...Ed L.
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