Spotlight for firemen

[andrey o]

Hello, I'm from Russia and I design flashlights for firemen. My aim is to make a flashlight with the narrowest spot (maximize its throw), and minimize its flood, as the flood is useless in smoke. As this flashlight is supposed to be a chest firefighter's flashlight, it should be quite compact.

I have realized that it is better to use LED chips with the smallest square (Cree XP-G provides higher candlepower than Cree XHP) and I have tried many different types of optics. As firefighter's flashlight should be compact (especially chest flashlight, like Streamlight Survivor), it is impossible to use long parabolic reflector (besides it stills has flood). TIR optics still provides some flood (Streamlight Survivor has "smoke cutters" in its kit in order to minimize flood light) I started to use convex lenses, as it cuts off almost all flood light. Then I decided to use flat Fresnel lenses in order to minimize weight and size. Here is my current solution: LS-A2M flashlight www.sila-s.com/ls-a2m
Fresnel lens in 50 mm diameter and 35 mm focal lens (so total chest flashlight thickness is 50 mm).

Is there any way to improve it and to have even smaller light spot (or smaller optics size)? I have only found Laser LED flashlights (LEP flashlights), but it is a too expensive solution. The other way is to use a set of lenses (like in a camera lens), but it will increase product size.

Any advice would be highly appreciated

 

[LEDphile]

As you've already found, shrinking the source size will allow you to shrink the optic size for the same beam angle. The flat-top LED packages provide higher candela than the domed packages, at the expense of lower total lumens, and are where I'd be looking as far as LED choice.

 

[RamBull]

W1 emitter? The Noctigon K1 with W1 green emitter has amazing throw and smaller foot print emitter.

 

[andrey o]

Thanks for replies. As for the smallest and flat top LED, I have used Cree XQ-E - it works really fine, however its efficacy (128 lm/W) is quite low comparing to modern LEDs. I will check Noctigon K1.

Has anybody seen flashlights using a set of lenses instead of a single lens or reflector? Maybe I should use a set of lenses in order to collect more light into a narrow beam and minimize flood light?

 

[desert.snake]

Did you ask this question to http://forum.fonarevka.ru/ too?

Now these more or less fit your criteria:
- Cree XP-P
- new Luminus SFT40

Luminus SFT-40 LED Emitter

Luminus SFT-40 LED Emitter

kaidomain.com

- and this Osram's

Osram KW CSLNM1_TG White 5600K LED Emitter

Osram KW CSLNM1_TG White 5600K LED Emitter

kaidomain.com

Osram KW CSLPM1_TG White 5400K LED

Osram KW CSLPM1_TG White 5400K LED

kaidomain.com

Ledil makes good lenses for miners

Product Search - LED lenses, reflectors and accessories - LEDiL

Our state-of-the-art optical solutions help to create light that enhances wellbeing,functionality, safety and sustainability. Find what matches your needs.

www.ledil.com

But why? I have friends firefighters, a long-range beam is really needed, if you work with a hose from a distance, you need to see where you pour the water. But for rescue teams in a smoky room, the narrowest beam is useless due to smoke and metal objects and mirrors can interfere with work, a powerful flood light is needed here, not too flood light, there may be about 30-40 degrees a central beam and a uniform fading of brightness to the edges ray, it will be better to see the whole environment around and where you are stepping.

If the flashlight is located on the chest, and not on the head, and has a very concentrated beam, then it is rather difficult to accurately direct it, especially if you have tools in your hands and you need to work with them, it is very inconvenient.

 

[LEDphile]

Thanks for replies. As for the smallest and flat top LED, I have used Cree XQ-E - it works really fine, however its efficacy (128 lm/W) is quite low comparing to modern LEDs. I will check Noctigon K1.

Has anybody seen flashlights using a set of lenses instead of a single lens or reflector? Maybe I should use a set of lenses in order to collect more light into a narrow beam and minimize flood light?

XQ-E HD or XQ-E HI? The HI is the flat-top version, and what you need for the narrow beams. The flat-top packages from Cree are XP-P and XQ-E HI (1mm2 die), XD16 (2mm2 die), and XP-L HI (4mm2 die).

 

[Ericbc7]

is there a color temperature that performs better in Smokey environments?

 

[andrey o]

is there a color temperature that performs better in Smokey environments?

There are some research showing that blue light performs worse (https://en.wikipedia.org/wiki/Selective_yellow) in smoky environments, so some believe that yellow light works better in a smoke (so do I )

 

[andrey o]

XQ-E HD or XQ-E HI? The HI is the flat-top version, and what you need for the narrow beams. The flat-top packages from Cree are XP-P and XQ-E HI (1mm2 die), XD16 (2mm2 die), and XP-L HI (4mm2 die).

XQ-E HI, yes (not HD).
I have also tested XD16, and I haven't achieved better results. It can consume a higher current (2A instead of 1A) but it doesn't provide a double light output. So I decided to use XQ-E HI for smaller flashlights (www.sila-s.com/ls-a2) and XP-L HI for bigger chest flashlights (www.sila-s.com/ls-a2m). Also I am using Cree XHP35 HI for the biggest flashlight (www.sila-s.com/ls-ct65m).

 

[andrey o]

Did you ask this question to http://forum.fonarevka.ru/ too?

Now these more or less fit your criteria:
- Cree XP-P
- new Luminus SFT40

Luminus SFT-40 LED Emitter

Luminus SFT-40 LED Emitter

kaidomain.com

- and this Osram's

Osram KW CSLNM1_TG White 5600K LED Emitter

Osram KW CSLNM1_TG White 5600K LED Emitter

kaidomain.com

Osram KW CSLPM1_TG White 5400K LED

Osram KW CSLPM1_TG White 5400K LED

kaidomain.com

Ledil makes good lenses for miners

Product Search - LED lenses, reflectors and accessories - LEDiL

Our state-of-the-art optical solutions help to create light that enhances wellbeing,functionality, safety and sustainability. Find what matches your needs.

www.ledil.com

But why? I have friends firefighters, a long-range beam is really needed, if you work with a hose from a distance, you need to see where you pour the water. But for rescue teams in a smoky room, the narrowest beam is useless due to smoke and metal objects and mirrors can interfere with work, a powerful flood light is needed here, not too flood light, there may be about 30-40 degrees a central beam and a uniform fading of brightness to the edges ray, it will be better to see the whole environment around and where you are stepping.

If the flashlight is located on the chest, and not on the head, and has a very concentrated beam, then it is rather difficult to accurately direct it, especially if you have tools in your hands and you need to work with them, it is very inconvenient.

Thanks, Cree XP-P looks really great, I will check all of these, and I will also ask for advice on http://forum.fonarevka.ru/
As for long-range beam, yes, you are right, there are many situations when you need a wide beam instead. But I decided to solve this by a separate high power LED with its own reflector. Now the flashlight LS-A2M has a separate spotlight LED and a separate wide-beam LED. Thus for each of them I can choose the best LED and the best optics. For wide beam I have organized it so that it provides an equal illumination, and it lights below other peoples' eyes (not blinding them)

 

[andrey o]

My goal is to eliminate this flood around hot spot. If the flashlight is used in smoky conditions, this flood light impairs visibility

 

[andrey o]

What I have done in order to remove flood light around hot spot:
1. Use LED with the smallest light emitting area
2. Use Fresnel lens
3. Use some tricks to eliminate parasitic reflections:
- black matter color of reflector (it should not reflect light, it should just hide wires)
- special stepped form of reflector
- black color of plastic ring between LED and reflector (yes, even that matters)

The problem is that Fresnel lens focal distance is 35 mm, and it is impossible to make the flashlight outer dimensions less than 50 mm.\
If I use lens with smaller focal distance, the light beam becomes wider. I wonder if it is possible to use a set of lenses in order to keep a narrow light beam but decrease size of optics.

 

[xxo]

What I have done in order to remove flood light around hot spot:
1. Use LED with the smallest light emitting area
2. Use Fresnel lens
3. Use some tricks to eliminate parasitic reflections:
- black matter color of reflector (it should not reflect light, it should just hide wires)
- special stepped form of reflector
- black color of plastic ring between LED and reflector (yes, even that matters)

The problem is that Fresnel lens focal distance is 35 mm, and it is impossible to make the flashlight outer dimensions less than 50 mm.\
If I use lens with smaller focal distance, the light beam becomes wider. I wonder if it is possible to use a set of lenses in order to keep a narrow light beam but decrease size of optics.

Have you tried de-domed or flat domed LEDs?

 

[andrey o]

flat domed LEDs

If I understand correctly, Cree High Intensity LEDs are flat domed. Now I don't have to de-dome LED, as Cree provides flat domed LED series (Cree XP-L High Intensity, Cree XQ-E high intensity)

 

[Scotty321]

Just brainstorming here...

Doesn't the Survivor have a black lens "plug" to help concentrate the beam for smokey environments? Have you tried it to compare? I wonder if you could replicate something like that on your setup... although I would assume it would reduce the efficiency.

 

[andrey o]

Just brainstorming here...

Doesn't the Survivor have a black lens "plug" to help concentrate the beam for smokey environments? Have you tried it to compare? I wonder if you could replicate something like that on your setup... although I would assume it would reduce the efficiency.

Yes, you are right about this Survivors' smoke cutter, the black one reduces flood light to 30-50%, and it reduces hot spot intensity very slightly. However a significant flood light is still present.

Frankly, I am rather skeptical regarding using TIR lens for hot spot LED light. TIR lenses provide brilliant efficiency (total lumens), but they can't provide high efficiency specially for hot spot from LED, I can see it on spatial diagrams attached. In my opinion, convex lenses work better, especially for high intensity (flat domed) LEDs

 

[parang]

There are some research showing that blue light performs worse (https://en.wikipedia.org/wiki/Selective_yellow) in smoky environments, so some believe that yellow light works better in a smoke (so do I )

View attachment 15201

Yes fog lights are yellow, should work in smoke too.

 

[Scotty321]

Yes, you are right about this Survivors' smoke cutter, the black one reduces flood light to 30-50%, and it reduces hot spot intensity very slightly. However a significant flood light is still present.

Frankly, I am rather skeptical regarding using TIR lens for hot spot LED light. TIR lenses provide brilliant efficiency (total lumens), but they can't provide high efficiency specially for hot spot from LED, I can see it on spatial diagrams attached. In my opinion, convex lenses work better, especially for high intensity (flat domed) LEDs

Just some more brainstorming...

Have you thought about sideway or backwards angled LED's in the reflector like the LED bulbs in headlights? This might allow you to aim the majority of the LED output onto whatever part of the reflector you want (to maximize spot and reduce spill). I don't know if this orientation would still require a shutter and lens (which would add to the length).

 

[desert.snake]

Just some more brainstorming...

Have you thought about sideway or backwards angled LED's in the reflector like the LED bulbs in headlights? This might allow you to aim the majority of the LED output onto whatever part of the reflector you want (to maximize spot and reduce spill). I don't know if this orientation would still require a shutter and lens (which would add to the length).

Pelican did this, but there was a weak LED and poor cooling, you can make a more powerful hanging pad for better cooling, but it is not clear if this would be better than the current lens.

 

[andrey o]

Pelican did this, but there was a weak LED and poor cooling, you can make a more powerful hanging pad for better cooling, but it is not clear if this would be better than the current lens.

Yes, you are right, that I will face cooling issues. If the LED is attached to the body, then the whole body helps to dissipate heat. If the LED is raised, then there should be some special solution for cooling. Some diving flashlights with side-oriented LEDs have a metal thermal conductor going outside the body and is cooled by water.

Many car LED lights have side oriented LEDs, but they have a huge thermal conductor and radiator, some even have fans - too complicated and heavy for a carried flashlight.