I have bought and installed some 10W and 30W LED outdoor floodlights. I
was interested by the fact that the width of the beam is considerable,
and the illumination is very even. I thus examined the pattern of the
light coming from the units, using a piece of welding glass. The large
pseudo-parabolic reflectors play no part in the beam shaping. The light
from the central LED cluster scarcely touches them, and through the
welding glass they appear black almost all over. The LEDs are recessed
and there is no direct path from the surface of the LEDS to most of the
the surface of the reflectors. The limits of the beam are defined by the
line from the LEDs to the edge of the frame. Hence the illumination is
very even but has a sharp edge cut-off. It appears that the reflectors
are purely for show.

I'm not complaining; the lights work well and are very impressive. But I
wonder if the market will mature and we will then have LED floods
without the unnecessary reflectors? The things would certainly look
neater without them.

Bill

Bill Wright wrote:
I have bought and installed some 10W and 30W LED outdoor floodlights. I
was interested by the fact that the width of the beam is considerable,
and the illumination is very even. I thus examined the pattern of the
light coming from the units, using a piece of welding glass. The large
pseudo-parabolic reflectors play no part in the beam shaping. The light
from the central LED cluster scarcely touches them, and through the
welding glass they appear black almost all over. The LEDs are recessed
and there is no direct path from the surface of the LEDS to most of the
the surface of the reflectors. The limits of the beam are defined by the
line from the LEDs to the edge of the frame. Hence the illumination is
very even but has a sharp edge cut-off. It appears that the reflectors
are purely for show.

I'm not complaining; the lights work well and are very impressive. But I
wonder if the market will mature and we will then have LED floods
without the unnecessary reflectors? The things would certainly look
neater without them.

Bill
Do they use the reflectors as a heat sink?

Bill Wright wrote in news:ldek0o$s8m$1
@speranza.aioe.org:

I have bought and installed some 10W and 30W LED outdoor floodlights.
I
was interested by the fact that the width of the beam is considerable,
and the illumination is very even. I thus examined the pattern of the
light coming from the units, using a piece of welding glass. The large
pseudo-parabolic reflectors play no part in the beam shaping. The
light
from the central LED cluster scarcely touches them, and through the
welding glass they appear black almost all over. The LEDs are recessed
and there is no direct path from the surface of the LEDS to most of
the
the surface of the reflectors. The limits of the beam are defined by
the
line from the LEDs to the edge of the frame. Hence the illumination is
very even but has a sharp edge cut-off. It appears that the reflectors
are purely for show.

I'm not complaining; the lights work well and are very impressive. But
I
wonder if the market will mature and we will then have LED floods
without the unnecessary reflectors? The things would certainly look
neater without them.

Bill

An interesting observation. I am hoping to change mine to LED but will
wait for them to mature. I guess the reflector is a marketing tool to
convince people that they are indeed a floodlight!

--

DerbyBorn

On 12/02/2014 01:49, Bill Wright wrote:
I have bought and installed some 10W and 30W LED outdoor floodlights. I
was interested by the fact that the width of the beam is considerable,
and the illumination is very even. I thus examined the pattern of the
light coming from the units, using a piece of welding glass. The large
pseudo-parabolic reflectors play no part in the beam shaping. The light
from the central LED cluster scarcely touches them, and through the
welding glass they appear black almost all over. The LEDs are recessed
and there is no direct path from the surface of the LEDS to most of the
the surface of the reflectors. The limits of the beam are defined by the
line from the LEDs to the edge of the frame. Hence the illumination is
very even but has a sharp edge cut-off. It appears that the reflectors
are purely for show.

I'm not complaining; the lights work well and are very impressive. But I
wonder if the market will mature and we will then have LED floods
without the unnecessary reflectors? The things would certainly look
neater without them.

Bill

I have also installed a 10watt and a 20watt LED light with pir sensors,
although I have not gone to the lengths you have in examining the
reflectors etc.

In article om,
F Murtz writes:
Bill Wright wrote:
I have bought and installed some 10W and 30W LED outdoor floodlights. I
was interested by the fact that the width of the beam is considerable,
and the illumination is very even. I thus examined the pattern of the
light coming from the units, using a piece of welding glass. The large
pseudo-parabolic reflectors play no part in the beam shaping. The light
from the central LED cluster scarcely touches them, and through the
welding glass they appear black almost all over. The LEDs are recessed
and there is no direct path from the surface of the LEDS to most of the
the surface of the reflectors. The limits of the beam are defined by the
line from the LEDs to the edge of the frame. Hence the illumination is
very even but has a sharp edge cut-off. It appears that the reflectors
are purely for show.

I'm not complaining; the lights work well and are very impressive. But I
wonder if the market will mature and we will then have LED floods
without the unnecessary reflectors? The things would certainly look
neater without them.

They are purely decorative, or perhaps, people wouldn't buy models
without them. When I fit different (better) LED emitters in these,
I don't bother to refit the reflector. LED designs are inherently
omni-directional.

Do they use the reflectors as a heat sink?

No. If anything, the reflector will very slightly reduce the heat
loss from the heat sink. With the reflector removed, you can feel
some IR emitted from the front of the heatsink too.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Bill Wright wrote:
I have bought and installed some 10W and 30W LED outdoor floodlights. I
was interested by the fact that the width of the beam is considerable,
and the illumination is very even. I thus examined the pattern of the
light coming from the units, using a piece of welding glass. The large
pseudo-parabolic reflectors play no part in the beam shaping. The light
from the central LED cluster scarcely touches them, and through the
welding glass they appear black almost all over. The LEDs are recessed
and there is no direct path from the surface of the LEDS to most of the
the surface of the reflectors. The limits of the beam are defined by the
line from the LEDs to the edge of the frame. Hence the illumination is
very even but has a sharp edge cut-off. It appears that the reflectors
are purely for show.

I'm not complaining; the lights work well and are very impressive. But I
wonder if the market will mature and we will then have LED floods
without the unnecessary reflectors? The things would certainly look
neater without them.

I'm not going out in the storm to look closely at mine, but it's a 20W
unit rather like this:

http://www.ebay.co.uk/itm/321299520316

The LEDs appear to be surface-mounted in a rectangular grid pattern on a
PCB, slightly bigger than a postage stamp.

--
Mike Barnes

F Murtz wrote:
Bill Wright wrote:
I have bought and installed some 10W and 30W LED outdoor floodlights. I
was interested by the fact that the width of the beam is considerable,
and the illumination is very even. I thus examined the pattern of the
light coming from the units, using a piece of welding glass. The large
pseudo-parabolic reflectors play no part in the beam shaping. The light
from the central LED cluster scarcely touches them, and through the
welding glass they appear black almost all over. The LEDs are recessed
and there is no direct path from the surface of the LEDS to most of the
the surface of the reflectors. The limits of the beam are defined by the
line from the LEDs to the edge of the frame. Hence the illumination is
very even but has a sharp edge cut-off. It appears that the reflectors
are purely for show.

I'm not complaining; the lights work well and are very impressive. But I
wonder if the market will mature and we will then have LED floods
without the unnecessary reflectors? The things would certainly look
neater without them.

Bill
Do they use the reflectors as a heat sink?

They seem to run almost cold.

Bill

DerbyBorn wrote:

An interesting observation. I am hoping to change mine to LED but will
wait for them to mature. I guess the reflector is a marketing tool to
convince people that they are indeed a floodlight!


Oh just do it. The 10W ones (lloytron) are only £12 + tax from CPC and
they are ever so well made. They are great. What an improvement over 17W
oyster lights!

Bill

In article ,
Mike Barnes writes:

I'm not going out in the storm to look closely at mine, but it's a 20W
unit rather like this:

http://www.ebay.co.uk/itm/321299520316

The LEDs appear to be surface-mounted in a rectangular grid pattern on a
PCB, slightly bigger than a postage stamp.

It's usually a single module with lots of LED chips in it.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]