Must an LED be flat? Why not shape like incan bulb?

[Lynx_Arc]

All in all I don't see LEDs becoming spherical in design anytime soon as I don't think that they will every get to 100% efficient there will always be considerable heat to deal with such that the emitters will have to be "connected" to metal heat sinks.
What would be optimal though would be a tiny LED sphere that outputs about 2000 lumens with very little heat that could be managed perhaps by a small diameter mounting metal pillar on one side. If this ever happened we could see it used in parabolic lenses and glass bulb type situations it would essentially be a direct replacement for a filament then with the exception of having electronics to manage power to the LED.

 

[defloyd77]

Today's LEDs can withstand higher temperatures and output higher amounts of heat such that you need even larger heatsinking than older luxeons could handle so either you have to throttle back LED power or it would make for a rather deep reflector to accomodate a rather long cylindrical heat sink on the back of the LED.

Todays LEDs produce much less heat than the older Luxeons at a given power, therefore you would need LESS heatsinking with a modern LED.

 

[Glenn7]

Tho they are more for decoration with low output for heat management there are some filament type bulbs out there https://www.bunnings.com.au/our-range/lighting-electrical/lighting/globes-tubes/decorative-globes

 

[RoJohn L. Sugg]

Todays LEDs produce much less heat than the older Luxeons at a given power, therefore you would need LESS heatsinking with a modern LED.

I do not think you are talking about LED in flashlight. Right?

 

[defloyd77]

I do not think you are talking about LED in flashlight. Right?

I am talking about in a flashlight. Why wouldn't I be?

It's simple, the more efficient the LED, the less energy is wasted as heat, no matter the application.

 

[Lynx_Arc]

Todays LEDs produce much less heat than the older Luxeons at a given power, therefore you would need LESS heatsinking with a modern LED.

I agree that they need less heatsinking at the same wattage input but todays LEDs are driven at higher wattage levels that the older luxeons. Typical flashlights these days tout 300-1000+ lumen outputs instead of 30-40 lumen outpouts the old luxeons had so the higher power inputs to these newer LEDs offset the gains in efficiency and lower heat output.

 

[defloyd77]

I agree that they need less heatsinking at the same wattage input but todays LEDs are driven at higher wattage levels that the older luxeons. Typical flashlights these days tout 300-1000+ lumen outputs instead of 30-40 lumen outpouts the old luxeons had so the higher power inputs to these newer LEDs offset the gains in efficiency and lower heat output.

30-40 lumens? You're thinking of the Luxeon I or III, I'm talking about the Luxeon V, they were 100+ lumens if I am not mistaken. With a well thought out balance between design and a realistic output, (no silly, 1 minute balls to the wall output) it could be done.

 

[Lynx_Arc]

30-40 lumens? You're thinking of the Luxeon I or III, I'm talking about the Luxeon V, they were 100+ lumens if I am not mistaken. With a well thought out balance between design and a realistic output, (no silly, 1 minute balls to the wall output) it could be done.

Luxeon V? 100 lumens for 5 watts is 20 lumens/watt which is worse than a luxeon at 30-40 lumens/watt

 

[defloyd77]

Luxeon V? 100 lumens for 5 watts is 20 lumens/watt which is worse than a luxeon at 30-40 lumens/watt

I didn't say 100 lumens for 5 watts. Looking at the specs from luxeonstar, 120 lumens @ 700mA, which would be about 2.5 watts or so.

The old Surefire L4 used a LuxV and was rated 100 lumens. From what I have read it got very hot.

 

[Lynx_Arc]

I didn't say 100 lumens for 5 watts. Looking at the specs from luxeonstar, 120 lumens @ 700mA, which would be about 2.5 watts or so.

The old Surefire L4 used a LuxV and was rated 100 lumens. From what I have read it got very hot.

Luxeon V are 6.8v emitters (not single die emitters) I believe 4 dies to them (2x2)

Luxeon 1 were 1 watt
Luxeon 3 were 3 watt
Luxeon 5 were 5 watts

 

[defloyd77]

Luxeon V are 6.8v emitters (not single die emitters) I believe 4 dies to them (2x2)

Luxeon 1 were 1 watt
Luxeon 3 were 3 watt
Luxeon 5 were 5 watts

The source I found said 3.99v max:shrug:

http://www.luxeonstar.com/lxhl-pw03-white-luxeon-v-portable-emitter-led-120lm

Regardless though, my point still stands, they were power hungry and ran hot, but Underwater Kinetics (not Pelican like I thought before) put 2 of them in a reflector facing light made mostly of plastic.

 

[Lynx_Arc]

The source I found said 3.99v max:shrug:

http://www.luxeonstar.com/lxhl-pw03-white-luxeon-v-portable-emitter-led-120lm

Regardless though, my point still stands, they were power hungry and ran hot, but Underwater Kinetics (not Pelican like I thought before) put 2 of them in a reflector facing light made mostly of plastic.

I've heard of them wiring the 4 dies in parallel somewhere but when that is done is doubles the current. The Luxeon V is a 5 watt emitter nominally that is why it is named as such.
I've never heard of a UK LED light with dual Luxeon V LEDs in it but then if it was a dive light I'm not very familiar with those and it is very possible to have rear facing LEDs in them I've seen them with such as they are cooled by the water on the lens they don't need metal heatsinking due to that option.

My point is such that the thirst for lumens has pretty much negated the gains of LED output/efficiency to make smaller lights with less heatsinking to them. With LEDs essentially 5-7 times more efficient instead of seeing lights 2-4 times the output we see them with 7-10 times the output too often which means the same amount of heat generated or even more heat. I think current high power LEDs can safely tolerate considerably higher temps and more heat than earlier LEDs could but without heatsinking they still can be overwhelmed by heat quickly.

The math pretty much doesn't give a good chance of a point source LED of output needed to feed the desires of the lumen addicted. It would have to be able to put out at least 500 lumens and unless you have an exotic heatsinking arrangement anything over probably a fraction of a watt of power through the LED will make for too many lumens to "air cool" the LED in a confined space.

 

[defloyd77]

I've heard of them wiring the 4 dies in parallel somewhere but when that is done is doubles the current. The Luxeon V is a 5 watt emitter nominally that is why it is named as such.
I've never heard of a UK LED light with dual Luxeon V LEDs in it but then if it was a dive light I'm not very familiar with those and it is very possible to have rear facing LEDs in them I've seen them with such as they are cooled by the water on the lens they don't need metal heatsinking due to that option.

My point is such that the thirst for lumens has pretty much negated the gains of LED output/efficiency to make smaller lights with less heatsinking to them. With LEDs essentially 5-7 times more efficient instead of seeing lights 2-4 times the output we see them with 7-10 times the output too often which means the same amount of heat generated or even more heat. I think current high power LEDs can safely tolerate considerably higher temps and more heat than earlier LEDs could but without heatsinking they still can be overwhelmed by heat quickly.

The math pretty much doesn't give a good chance of a point source LED of output needed to feed the desires of the lumen addicted. It would have to be able to put out at least 500 lumens and unless you have an exotic heatsinking arrangement anything over probably a fraction of a watt of power through the LED will make for too many lumens to "air cool" the LED in a confined space.

I guess really it depends on the lights intended purpose, size, price, materials, etc. At this point, it's sounding like a pretty niche light, so copper would be a viable option, especially for the protruding heatsink.

Anyway, I think the topic has veered a bit too far off from the original question of an incandescent like LED, I'm quite curious about those side emmiting LEDs and whether or not they were any good at helping with more light hit reflectors and increasing throw.

 

[fivemega]

Must an LED be flat? Why not shape like incan bulb?

Filament of incan can be far from it's base without problem but an LED must be as close as possible to heat sink.
Well driven LED sitting on long tower (far from heat sink) will not do any good even if it has copper, bulky and finned heat sink.
Sitting LED directly on base of heat sink will be much more efficient.
This explains why not high power LED for MN type modules.

How about making the LED on the inside surface of a parabola? From the focal point to a couple of mm.

A light source must be only one, as small as possible and placed on focal point of parabola. So each parabola has one focal point and that point is not on surface of parabola or far from focal point.

 

[Lynx_Arc]

I guess really it depends on the lights intended purpose, size, price, materials, etc. At this point, it's sounding like a pretty niche light, so copper would be a viable option, especially for the protruding heatsink.

Anyway, I think the topic has veered a bit too far off from the original question of an incandescent like LED, I'm quite curious about those side emmiting LEDs and whether or not they were any good at helping with more light hit reflectors and increasing throw.

I've never seen one, but I think the general consensus was they weren't anything spectacular. I think the onset of reflectors specifically designed for LEDs negated the need for side emitting LEDs entirely

 

[lumen aeternum]

>--Quote (Originally by lumen aeternum)--- How about making the LED on the inside surface of a parabola? From the focal point to a couple of mm.
---End Quote---
*A light source must be only one, as small as possible and placed on focal point of parabola. So each parabola has one focal point and that point is not on surface of parabola or far from focal point. *
>

I'll try again. Instead of a point source of light at the focal point, which emits light that bounces off the parabola surface, do it the other way around. But only put emitter on the portions of the parabola surface which are going to emit in a narrow pencil beam.
***

re recoil design: You could have a cylindical/finned heat sink extending beyond the lens as far as necessary.
***

If a pencil beam is desired, what % of Watts are wasted in corona/spill? Shape the beam & reduce the Watts.

 

[Lynx_Arc]

>--Quote (Originally by lumen aeternum)--- How about making the LED on the inside surface of a parabola? From the focal point to a couple of mm.
---End Quote---
*A light source must be only one, as small as possible and placed on focal point of parabola. So each parabola has one focal point and that point is not on surface of parabola or far from focal point. *
>

I'll try again. Instead of a point source of light at the focal point, which emits light that bounces off the parabola surface, do it the other way around. But only put emitter on the portions of the parabola surface which are going to emit in a narrow pencil beam.
***

re recoil design: You could have a cylindical/finned heat sink extending beyond the lens as far as necessary.
***

If a pencil beam is desired, what % of Watts are wasted in corona/spill? Shape the beam & reduce the Watts.

You would have to have almost an infinite number of laser beams to mimic the light off a parabolic reflector. If you could control beams that well there would probably be little need for a reflector you could just have each individual beam aimed at a spot in the distance and have a flat panel of them.

 

[Enderman]

Here are several light bulbs that use "filament" LEDs:
https://edisonlightglobes.com/Shop/shop/240-v-globes/3-watt-dimmable-filament-led-e27-candle-bulb/
http://www.lighting.philips.com/main/prof/led-lamps-and-systems/led-lamps/classic-filament-led-lamps
https://www.superbrightleds.com/mor...-bulb-with-4-watt-filament-led-dimmable/2142/
There are actually many bulbs like this.
Cree recently won a lawsuit against Feit to use this type of LED filament.

 

[Lynx_Arc]

Here are several light bulbs that use "filament" LEDs:
https://edisonlightglobes.com/Shop/shop/240-v-globes/3-watt-dimmable-filament-led-e27-candle-bulb/
http://www.lighting.philips.com/main/prof/led-lamps-and-systems/led-lamps/classic-filament-led-lamps
https://www.superbrightleds.com/mor...-bulb-with-4-watt-filament-led-dimmable/2142/
There are actually many bulbs like this.
Cree recently won a lawsuit against Feit to use this type of LED filament.

I think the OP is looking for a laser beam type of throwing flashlight, a filament LED is IMO only good for flood lighting.