A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

Okay, I don't know a darned thing about lights, but I was wondering about how practical my idea to improve the A2 would be. The current prob. with the A2 is the LED's take up valuable reflector space, therefore decreasing the total possible output of the incan, as well as creating a less than smooth beam pattern compared to other SF's such as the E2. So, my idea was to make the LED's a little bit brighter, and recess them deeper into the reflector, then cover them with a one-way mirror sort of coating so that the incan beam would reflect off of the coating, but the embedded LEDs would also be able to shine through it as well. Am I making sense here?

Anyway, is this a feasible idea, or am I ignoring some obvious issue (heat, laws or reflective properties, etc) It just sounded good to me as a way of improving total output of the incan, and smoothing the beam out a little bit.

EDIT: here's a picture to explain what I'm talking about

It's a great idea but the A2's beam is pretty good at medium to long ranges. The problem is that if you recess the Leds you will not get a nice floody low beam, you will have three spots of light instead. I sanded the tops of my leds to make the beam a smoother flood than before. Also, another problem with the mirror idea would be that the mirrors will need the same exaxt parabolic shape as the reflector in order for that idea to work properly. If you take your A2 apart and pull the led ring out you will see that there is not that much clearance to mount the leds so that they sit deeper in the reflector. Maybe you could use some 3mm leds instead.

Just my 0.02$

I don't think it's that feasible I'm afraid. The A2's beam is great unless you hunt white walls at close range (1-2 metres) which is not the purpose of the A2. I've used the A2 as my EDC and in use it really shines.

Al

Re: A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

<Elmer> be wery wery quwiet i'm hunting walls bahahhahaha... </Elmer>

I found the stock A2 beam to be pretty good for EDC as well, I carry it round in a holster into the schols a walk into and they're all like 'what's that?'
Convert them to flashaholism young i says!

It's a good idea in but remember the LEDs wouldn't be able to take advantage of the reflector to bounce some of it's sidespill forwards as well when you are a bit away from a wall or your shining targets the Incan beam doesn't show any symptoms of having three holes in the reflector, i can only see the holes when i'm like 10cm away from a wall (and that's a LED task anyway)

Re: A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

As far as I know, the transmission you get through one-way mirrors just isn't good enough for flashlight use either. If you want to keep all the light from the incan going out of the reflector you'd probably be limited to 50% or worse of the led light making it through the reflector. Which would make the leds very dim.

Nice idea though - its the little new improved ideas that keep innovation rolling along nicely...

Re: A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

There is no such thing as a "one-way-mirror". If you invented one, you'd get the Nobel Price for Physics immediately, beacuse a "one-way-mirror" allows you to build a Perpetual motion

Re: A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

Spacemarine said:

beacuse a "one-way-mirror" allows you to build a Perpetual motion

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Just for arguments sake, why? You have transmission losses even with no reflectivity(converts to heat)

Luna said:

Just for arguments sake, why? You have transmission losses even with no reflectivity(converts to heat)

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Very simple. Just imagine you have pieces of metall in a vaccum chamber, separated by a one-way-mirror. Both these pieces of metall are at the same temperature and are emitting the normal IR-radiation due to their temperature. Becasue there is a one-way-mirror between them, one will only emit it's radiation to the mirror, the other one will have his own radiation reflected at the mirror and will even get the radiation of the other piece of metal. This results in one piece cooling down and the other one heating up.

Now that you have two pieces of metal at a different temperature, you could power a heat engine with that, a steam engine for example.

Spacemarine said:

Very simple. Just imagine you have pieces of metall in a vaccum chamber, separated by a one-way-mirror. Both these pieces of metall are at the same temperature and are emitting the normal IR-radiation due to their temperature. Becasue there is a one-way-mirror between them, one will only emit it's radiation to the mirror, the other one will have his own radiation reflected at the mirror and will even get the radiation of the other piece of metal. This results in one piece cooling down and the other one heating up.

Now that you have two pieces of metal at a different temperature, you could power a heat engine with that, a steam engine for example.

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This first half of this may work in theory (although to be honest I haven't fully thought it through yet - I'm tired), but in practise it is flawed.

The problem is this - if you have 2 pieces of metal in a vacuum chamber (I assume you put them in a vacuum chamber to prevent heat loss), how the hell do you do anything with it? If you try and run a steam engine, it will cool down the block of metal. All you end up with is 2 cold damp blocks of metal after all the steam from your 'engine' condenses. Having 2 things at different temperatures does not make an engine. And the problem with any 'perpetul motion device' is that they might work in theory, the problem is they always stop working whenever you try and use the energy for anything.

And I'm afraid one way mirrors do exist. In their simplest form they are the shiny glass windows you see on buildings. The people inside can see you, you just can't see back. They aren't perfect, but they are a one way mirror.

In their more advanced form, they are used in various optical instruments. Holograms require a one way mirror to 'add' the light together from 2 sources to create the 3d image you see. Many other similar optical instruments use them, and they are available in various reflection/transmissions combinations (eg transmit 60%, reflect 40%) for various mathematical operations with beams of light. Believe it or not, it is possible to do complex mathematics merely with beams of light if you bounce it round a few times (Fourier Transform anybody).

Spacemarine said:

Very simple. Just imagine you have pieces of metall in a vaccum chamber, separated by a one-way-mirror. Both these pieces of metall are at the same temperature and are emitting the normal IR-radiation due to their temperature. Becasue there is a one-way-mirror between them, one will only emit it's radiation to the mirror, the other one will have his own radiation reflected at the mirror and will even get the radiation of the other piece of metal. This results in one piece cooling down and the other one heating up.

Now that you have two pieces of metal at a different temperature, you could power a heat engine with that, a steam engine for example.

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The perp motion argument doesn't negate the idea of a 1 way mirror

The 2nd law would be violated if you exclude the emissions of the heated mirror back to the "cooler" plate. The mirror/barrier will heat up and emit energy back to the plate. This is of course only if we can develop an interface to accomplish the task in reality.

A one way mirror just means that radiation is allowed in one direction and not the other. We obviously know that partial silvering gives the illusion of a 1 way mirror, so that isn't worth discussing. However given the fact that wavelength and efficiency is not implied in the terming 'one way mirror', we can introduce a dichromic filter of sorts. Just because you have a 90%reflectivity, doesn't mean 10% goes back thru. Some of the energy is converted to heat.

I guess the best example of a true 1 way mirror is when you have an emitter inside event horizon of a black hole

Re: A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

The output of the A2 is pretty good the way it comes. McGizmo, using his new little Integrated Sphere, measured 79 lumens, I think with leds removed. My bounce tests show the A2 has just slightly less output than my KL4, output not lux.

Bill

Re: A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

The one way mirrors in stores and what you see on the sides of buildings are just semi-reflecting surfaces. They let some light through and reflect some. The "one way" effect happens when it's darker on one side of the glass than on the other side. For example, the outside of a building is in sunlight while the inside just has indoor lighting (or maybe not even that, if the lights are turned off). So you do get some light leaving the building through the glass, but the reflected light is much brighter (since there's much more light to reflect) and swamps out the light from the inside.

If you go to a store where there's one-way mirrors over the meat fridge or whatever, and put your face close to the mirror from the "outside", you can see through it.

Re: A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

How about if you pull the LEDs out of the big reflector entirely, put a ring of them (each with its own small reflector) around the outside rim of the big reflector?

Re: A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

paulr said:

The one way mirrors in stores and what you see on the sides of buildings are just semi-reflecting surfaces. They let some light through and reflect some. The "one way" effect happens when it's darker on one side of the glass than on the other side. For example, the outside of a building is in sunlight while the inside just has indoor lighting (or maybe not even that, if the lights are turned off). So you do get some light leaving the building through the glass, but the reflected light is much brighter (since there's much more light to reflect) and swamps out the light from the inside.

If you go to a store where there's one-way mirrors over the meat fridge or whatever, and put your face close to the mirror from the "outside", you can see through it.

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ALL one way mirrors can be seen through from both sides to some extent. It's just that the reflected light masks the transmitted light from the outside when you are looking from the 'mirror' side. When you peer closely through the shop window you just reduce the amount of light hitting the glass from your side (and hence reducing the amount of glass reflected back at you from your own side). This allows you to see the small amount of transmitted light.

Re: A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

So now that it's been established that there's no such thing as a one-way mirror...

How about this: make the LEDs retractable, and add a second reflector (or just sections of a reflector) right behind the main one, which can be rotated to cover the holes, like how sealable salt shakers work?

Yeah, lots of extra moving parts needed...

Re: A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

I know there's no such thing as a true one-way mirror, my point was it would help, even if only some of the incan beam was reflected. And obviously, the LEDs would have to be stronger just to transmit as much light as they are now.

Re: A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

SCblur said:

I know there's no such thing as a true one-way mirror, my point was it would help, even if only some of the incan beam was reflected. And obviously, the LEDs would have to be stronger just to transmit as much light as they are now.

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I'd imagine the output with the LEDs on will compensate for the small loss caused by the 3 holes. Not to mention the loss isn't as bad as the backplane losses from the opening for the main lamp assembly because the distance from the filament.

Re: A theoretical upgrade to the A2, from somebody who doesn't know what he's talkin bout

Transmissive mirrors, or semi-reflective mirrors are an everyday reality, and they don't break any law of physics.
A ruby laser uses one of these semi-reflective mirror.
A dichroic reflector is another flavor of a surface that reflect some wavelengths and transmit others.

In the case of the A2 reflector the idea is neat in general, but the transmission losses would be of an excessive magnitude, and the beam from the 3 LEDs would not form correctly.

On a different but related issue, I would say that specialized optics with concurrent graded reflective and transmissive properties are the future of specialized light sources, to include flashlights. Specialized optics allows the coupling of separate light sources in one beam, with the desired focusing. Specialized CAD software will allow the design of cheap optics that can do wonders. Optics will do to reflectors what LED did to incandescent bulbs.

Anthony