Modify LED Headlight Beam ? ?

I'm starting to experiment with ways to alter the beam light dispersion
of the typical LED bike headlights.

Most of them put out a "pencil beam" and not enough dispersed or
scattered light to be something you can really ride with.

I have had this experience with Cateye EL300 and EL500 and with the Nite
Hawk LED Emitter (non-digital).

Initial experiments are with a flat Fresnel plastic lens, of the type
commonly sold as a flat plastic pocket magnifying lens. (The one with
the rings of grooves that trick the light into thinking it is hitting a
single curved surface, more or less.)

Holding it over the front of the light, any of the above, really spreads
the light out.

Variations eventually will include slicing the Fresnel lens into parts
and covering part of the headlight so as to allow some of the beam to
stay "pencil beam" and yet disperse some light for better near bike
visibility, particularly for turns.

If one had Fresnel lenses of different focal lengths, one could probably
tailor the light beam into something much more useful than the simple
"pencil beam" that is really bright.

I find that in turning a corner, it is riding into the darkness off of
the bright pencil beam.... and that is no fun.

Tonight I am off with the three lights mentioned and a roll of clear
tape to experiment.

I already know that the beam is more dispersed with the whole headlight
face covered with the Fresnel lens.



--
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2) Exercise: It's Non-Negotiable..... Chapter 22 title, Atkins book
3) Don't Diet Without Supplimental Nutrients... Chapter 23 title, Atkins
book
4) A sensible eating plan, and follow it. (Atkins, Self Made or Other)

"jbuch" wrote: (clip) I find that in turning a corner, it is riding into
the darkness off of the bright pencil beam.... and that is no fun. (clip)
^^^^^^^^^^^^^
How about a helmet light, along with your pencil-beam, handlebar mounted LED
headlight?

jbuch wrote:
I'm starting to experiment with ways to alter the beam light dispersion
of the typical LED bike headlights.

Most of them put out a "pencil beam" and not enough dispersed or
scattered light to be something you can really ride with.

Have you looked into the Planet Bike SuperSpot 1W LED light?

It's definitely not a "pencil beam". For the first time since getting
that light along with an EL-500, I rode with the two combined and they
complement each other very well.


--
I do not accept unsolicited commercial e-mail. Remove NO_UCE for
legitimate replies.

jbuch wrote:
I'm starting to experiment with ways to alter the beam light dispersion
of the typical LED bike headlights.

Most of them put out a "pencil beam" and not enough dispersed or
scattered light to be something you can really ride with.

I have had this experience with Cateye EL300 and EL500 and with the Nite
Hawk LED Emitter (non-digital).

Initial experiments are with a flat Fresnel plastic lens, of the type
commonly sold as a flat plastic pocket magnifying lens. (The one with
the rings of grooves that trick the light into thinking it is hitting a
single curved surface, more or less.)


The Fresnel lens did spread the light beam on all headlights.

EL-300 The result was five light "halos" rather than one beam. The
light intensity was pretty low as a result of the spreading. It was more
or less useless. If you spread out 400 claimed candlepower, it is
pretty dim.


EL-500 The result was a large light "halo" rather than a pencil. The
effort to cover just 1/2 of the beam with the Fresnel lens produced a
mixture of a "beam" and a "Halo", but it wasn't a very useful pattern
for riding. Again, this lamp produces a claimed 1200 candlepower, and
when spread out very much, it isn't a lot.

Nite Hawk LED Emitter - The result was a larger diameter spot rather
than the narrow pencil. There still wasn't much scattered light to see
ahead of you while turning, or thinking about turning. The larger spot
was a nicer medium speed ride than anything else, including any of the
headlamps without the Fresnel lens.

I would suspect that _I_ would be happy wtih outputs of nearly five
times higher than the EL-500 or the Nite Hawk - and in a beamwhich has
riding functinality.


I saw a 1928 Ford Model A today on my exercise ride and stopped to take
a look.

The headlamps had the classic bulb, reflector, and focusing front lens.
The focus elements in the front lens were simple vertical cylinder
sections, so as to spread the beam out laterally. No optical elements
were in use to control the fine details of beam forming except in the
lateral direction.

More modern headlamps that I looked at had complex optical segmentation
of small lenses that appeared to provide beam manipulation in both
directions which may be why modern auto headlamps perform pretty well.

Bicycle LED lights currently have none of this secondary beam forming
optical design.

I can't speak to the beam optics control of HID or tungsten-halide lamps.

At anyy rate, LED headlights have a long way to go to be mature. Right
now, they are immature in design and performance.

Jim

jbuch wrote:
jbuch wrote:
I'm starting to experiment with ways to alter the beam light
dispersion of the typical LED bike headlights.

Most of them put out a "pencil beam" and not enough dispersed or
scattered light to be something you can really ride with.

I have had this experience with Cateye EL300 and EL500 and with the
Nite Hawk LED Emitter (non-digital).

Initial experiments are with a flat Fresnel plastic lens, of the type
commonly sold as a flat plastic pocket magnifying lens. (The one with
the rings of grooves that trick the light into thinking it is
hitting a single curved surface, more or less.)


The Fresnel lens did spread the light beam on all headlights.

EL-300 The result was five light "halos" rather than one beam. The
light intensity was pretty low as a result of the spreading. It was
more or less useless. If you spread out 400 claimed candlepower, it
is pretty dim.


EL-500 The result was a large light "halo" rather than a pencil. The
effort to cover just 1/2 of the beam with the Fresnel lens produced a
mixture of a "beam" and a "Halo", but it wasn't a very useful pattern
for riding. Again, this lamp produces a claimed 1200 candlepower, and
when spread out very much, it isn't a lot.

Nite Hawk LED Emitter - The result was a larger diameter spot rather
than the narrow pencil. There still wasn't much scattered light to
see ahead of you while turning, or thinking about turning. The larger
spot was a nicer medium speed ride than anything else, including any
of the headlamps without the Fresnel lens.

I would suspect that _I_ would be happy wtih outputs of nearly five
times higher than the EL-500 or the Nite Hawk - and in a beamwhich has
riding functinality.


I saw a 1928 Ford Model A today on my exercise ride and stopped to
take a look.

The headlamps had the classic bulb, reflector, and focusing front
lens. The focus elements in the front lens were simple vertical
cylinder sections, so as to spread the beam out laterally. No optical
elements were in use to control the fine details of beam forming
except in the lateral direction.

More modern headlamps that I looked at had complex optical
segmentation of small lenses that appeared to provide beam
manipulation in both directions which may be why modern auto
headlamps perform pretty well.
Bicycle LED lights currently have none of this secondary beam forming
optical design.

I can't speak to the beam optics control of HID or tungsten-halide
lamps.
At anyy rate, LED headlights have a long way to go to be mature. Right
now, they are immature in design and performance.

The lenses are designed from the factory to focus very sharply. They give
off comparatively little light to the sides, making reflectors kinda
useless. A specific prism might be able to split the light just the way you
want it. Personally, I would just mount a light to the helmet and be done
with it.


--
Phil, Squid-in-Training

jbuch wrote:
jbuch wrote:
I'm starting to experiment with ways to alter the beam light dispersion
of the typical LED bike headlights.

Most of them put out a "pencil beam" and not enough dispersed or
scattered light to be something you can really ride with.

I have had this experience with Cateye EL300 and EL500 and with the Nite
Hawk LED Emitter (non-digital).

Initial experiments are with a flat Fresnel plastic lens, of the type
commonly sold as a flat plastic pocket magnifying lens. (The one with
the rings of grooves that trick the light into thinking it is hitting a
single curved surface, more or less.)


The Fresnel lens did spread the light beam on all headlights.

EL-300 The result was five light "halos" rather than one beam. The
light intensity was pretty low as a result of the spreading. It was more
or less useless. If you spread out 400 claimed candlepower, it is
pretty dim.


EL-500 The result was a large light "halo" rather than a pencil. The
effort to cover just 1/2 of the beam with the Fresnel lens produced a
mixture of a "beam" and a "Halo", but it wasn't a very useful pattern
for riding. Again, this lamp produces a claimed 1200 candlepower, and
when spread out very much, it isn't a lot.

Nite Hawk LED Emitter - The result was a larger diameter spot rather
than the narrow pencil. There still wasn't much scattered light to see
ahead of you while turning, or thinking about turning. The larger spot
was a nicer medium speed ride than anything else, including any of the
headlamps without the Fresnel lens.

I would suspect that _I_ would be happy wtih outputs of nearly five
times higher than the EL-500 or the Nite Hawk - and in a beamwhich has
riding functinality.

You may want to visit
http://www.enhydralutris.de/Fahrrad/LEDWerfer0402/ and punch it into
www.babelfish.com if you don't read German. (This site was mentioned
in a another recent thread.) Their approach, working with Luxeon
super-bright LEDs, is to modify a commercial generator headlight shell.


Really, to light the road effectively, it's best to have optics
designed for that purpose. I've tried something similar to what you're
trying, with similar lack of success, although I started with a
brighter light. I had lenses that spread the light far too much side
to side, and I had lenses that made almost no difference, or gave too
diffuse a beam. You need precision. I don't think you'll get it by
accident.



I saw a 1928 Ford Model A today on my exercise ride and stopped to take
a look.

The headlamps had the classic bulb, reflector, and focusing front lens.
The focus elements in the front lens were simple vertical cylinder
sections, so as to spread the beam out laterally. No optical elements
were in use to control the fine details of beam forming except in the
lateral direction.

More modern headlamps that I looked at had complex optical segmentation
of small lenses that appeared to provide beam manipulation in both
directions which may be why modern auto headlamps perform pretty well.

Bicycle LED lights currently have none of this secondary beam forming
optical design.

I can't speak to the beam optics control of HID or tungsten-halide lamps.

At anyy rate, LED headlights have a long way to go to be mature. Right
now, they are immature in design and performance.

I think Cateye's LEDs have paid some attention to optics. I think
that's what their "Opticube" advertising term is supposed to mean.

Interestingly, older Cateye halogen lamps (the cheap ones powered by
flashlight batteries) had what seem to be parabolic reflectors and
faceted lenses, some with front reflectors to reflect what would be
"lost" light back toward the parabolic reflctor. The paraboloid throws
out a straight parallel beam; the lens shapes it to fit the road,
usually into a rectangle or trapezoid.

Newer Cateye halogen lamps (the Micro whatever) dispense with the
faceted lens. They seem to use a complex, computer-generated reflector
to shape the beam directly. The idea seems to be to reduce losses in
the front lens.

To my eye, the beam shape is more precise with the old system; but the
total light output may be more with the new system. Certainly, most
new cars have gone to something similar. I know our Pontiac Vibe has
no faceted lenses on the headlights, and the beam's upper cutoff and
uniformity of spread are both outstanding.

Cateye's LED lamps seem less precise to me, but not too bad. I rode
next to a guy who had the CE-EL500. It's beam was somewhat amorphous,
and not as useful to my eye as my halogen generator lamp, but it wasn't
bad.


- Frank Krygowski

Phil, Squid-in-Training wrote:
jbuch wrote:

jbuch wrote:

I'm starting to experiment with ways to alter the beam light
dispersion of the typical LED bike headlights.

Most of them put out a "pencil beam" and not enough dispersed or
scattered light to be something you can really ride with.

I have had this experience with Cateye EL300 and EL500 and with the
Nite Hawk LED Emitter (non-digital).

Initial experiments are with a flat Fresnel plastic lens, of the type
commonly sold as a flat plastic pocket magnifying lens. (The one with
the rings of grooves that trick the light into thinking it is
hitting a single curved surface, more or less.)


The Fresnel lens did spread the light beam on all headlights.

EL-300 The result was five light "halos" rather than one beam. The
light intensity was pretty low as a result of the spreading. It was
more or less useless. If you spread out 400 claimed candlepower, it
is pretty dim.


EL-500 The result was a large light "halo" rather than a pencil. The
effort to cover just 1/2 of the beam with the Fresnel lens produced a
mixture of a "beam" and a "Halo", but it wasn't a very useful pattern
for riding. Again, this lamp produces a claimed 1200 candlepower, and
when spread out very much, it isn't a lot.

Nite Hawk LED Emitter - The result was a larger diameter spot rather
than the narrow pencil. There still wasn't much scattered light to
see ahead of you while turning, or thinking about turning. The larger
spot was a nicer medium speed ride than anything else, including any
of the headlamps without the Fresnel lens.

I would suspect that _I_ would be happy wtih outputs of nearly five
times higher than the EL-500 or the Nite Hawk - and in a beamwhich has
riding functinality.


I saw a 1928 Ford Model A today on my exercise ride and stopped to
take a look.

The headlamps had the classic bulb, reflector, and focusing front
lens. The focus elements in the front lens were simple vertical
cylinder sections, so as to spread the beam out laterally. No optical
elements were in use to control the fine details of beam forming
except in the lateral direction.

More modern headlamps that I looked at had complex optical
segmentation of small lenses that appeared to provide beam
manipulation in both directions which may be why modern auto
headlamps perform pretty well.
Bicycle LED lights currently have none of this secondary beam forming
optical design.

I can't speak to the beam optics control of HID or tungsten-halide
lamps.
At anyy rate, LED headlights have a long way to go to be mature. Right
now, they are immature in design and performance.


The lenses are designed from the factory to focus very sharply. They give
off comparatively little light to the sides, making reflectors kinda
useless. A specific prism might be able to split the light just the way you
want it. Personally, I would just mount a light to the helmet and be done
with it.



This is my twin Luxeon setup on my triathlon bike.
http://www.hyperactive.oz.nf/Lights2/Luxeon2.htm

Marty

Marty wrote:
Phil, Squid-in-Training wrote:
jbuch wrote:

jbuch wrote:

I'm starting to experiment with ways to alter the beam light
dispersion of the typical LED bike headlights.

Most of them put out a "pencil beam" and not enough dispersed or
scattered light to be something you can really ride with.

I have had this experience with Cateye EL300 and EL500 and with the
Nite Hawk LED Emitter (non-digital).

Initial experiments are with a flat Fresnel plastic lens, of the
type commonly sold as a flat plastic pocket magnifying lens. (The
one with the rings of grooves that trick the light into thinking
it is hitting a single curved surface, more or less.)


The Fresnel lens did spread the light beam on all headlights.

EL-300 The result was five light "halos" rather than one beam. The
light intensity was pretty low as a result of the spreading. It was
more or less useless. If you spread out 400 claimed candlepower, it
is pretty dim.


EL-500 The result was a large light "halo" rather than a pencil. The
effort to cover just 1/2 of the beam with the Fresnel lens produced
a mixture of a "beam" and a "Halo", but it wasn't a very useful
pattern for riding. Again, this lamp produces a claimed 1200
candlepower, and when spread out very much, it isn't a lot.

Nite Hawk LED Emitter - The result was a larger diameter spot rather
than the narrow pencil. There still wasn't much scattered light to
see ahead of you while turning, or thinking about turning. The
larger spot was a nicer medium speed ride than anything else,
including any of the headlamps without the Fresnel lens.

I would suspect that _I_ would be happy wtih outputs of nearly five
times higher than the EL-500 or the Nite Hawk - and in a beamwhich
has riding functinality.


I saw a 1928 Ford Model A today on my exercise ride and stopped to
take a look.

The headlamps had the classic bulb, reflector, and focusing front
lens. The focus elements in the front lens were simple vertical
cylinder sections, so as to spread the beam out laterally. No
optical elements were in use to control the fine details of beam
forming except in the lateral direction.

More modern headlamps that I looked at had complex optical
segmentation of small lenses that appeared to provide beam
manipulation in both directions which may be why modern auto
headlamps perform pretty well.
Bicycle LED lights currently have none of this secondary beam
forming optical design.

I can't speak to the beam optics control of HID or tungsten-halide
lamps.
At anyy rate, LED headlights have a long way to go to be mature.
Right now, they are immature in design and performance.


The lenses are designed from the factory to focus very sharply. They give
off comparatively little light to the sides, making
reflectors kinda useless. A specific prism might be able to split
the light just the way you want it. Personally, I would just mount
a light to the helmet and be done with it.



This is my twin Luxeon setup on my triathlon bike.
http://www.hyperactive.oz.nf/Lights2/Luxeon2.htm

Marty

Nice! Reminds me of Johnny 5.

--
Phil, Squid-in-Training

This is my twin Luxeon setup on my triathlon bike.
http://www.hyperactive.oz.nf/Lights2/Luxeon2.htm

Marty

I did more or less the same thing. Two Cateye EL-500 mounted on a space
saver bar, and a helmet mounted Princeton Tec EOS (1 watt LED) on my helmet,
and it works fairly good. The EOS light spreads out, so you can see in the
turns, it's a great light. 2 hours on 3 AAA, so it burns through them
quick. But you put 3 Lithium AAA's in it, and you don't even feel any
weight on your helmet.

the cateye has a pencil beam?? tilt it up!
gee marty's bike make me feel
like a swineherd