LEDs & Other Stuff - (Reference Guide)

[The_Driver1 (The_Driver)]

@yoosefheidari

@The_Driver

I calculate 124m diameter in 1000m distance using my method (ignoring the corners of the LED).

De-doming the LED and driving it with a high current (FET driver) will get you your 1.5km of throw. The hotspot will be 50% smaller.

i think 124 meter spot at 1KM isn’t that bad for XHP70.2 are you agree? i’m using my DIY fet driver now and it’s max current can go around 20A. i have another question.how de-doming can affect on spot diameter?

Read this.

[yoosefheidari]

@The_Driver

@yoosefheidari

it seems there is no way to have a small spot(my goal) with a 76 milimeter lens and collect whole light! so is a reflector better than lens for this purpose?i think a reflector can collect more light(mean less losses) and can concentrate while light in one point and here there is no diameter’s problem of lenses. is that true?

There is. You need to use a pre-collimator (small spheric lens very close to the LED, LED needs to be de-domed). This is the only way to collect as much light as possible with an aspheric lens. If you then want a small hotspot, you just need to use a suitably small LED.

Here is a formula you can us to calculate the size of the hotspot:

luminous_intensity_in_specific_distance [lux @ xx m] = luminous_flux [lumens] / area [m²]

Generally you need to know how many lumens are actually in the beam. For reflector lights you can assume 75% of the total lumens.

Here you can find some nice calculators to help you.

i have an idea.can i use a 80 degree reflector in combination with my lens to collect whole light?is that a good idea?

[The_Driver1 (The_Driver)]

@yoosefheidari

@The_Driver

@yoosefheidari

it seems there is no way to have a small spot(my goal) with a 76 milimeter lens and collect whole light! so is a reflector better than lens for this purpose?i think a reflector can collect more light(mean less losses) and can concentrate while light in one point and here there is no diameter’s problem of lenses. is that true?

There is. You need to use a pre-collimator (small spheric lens very close to the LED, LED needs to be de-domed). This is the only way to collect as much light as possible with an aspheric lens. If you then want a small hotspot, you just need to use a suitably small LED.

Here is a formula you can us to calculate the size of the hotspot:

luminous_intensity_in_specific_distance [lux @ xx m] = luminous_flux [lumens] / area [m²]

Generally you need to know how many lumens are actually in the beam. For reflector lights you can assume 75% of the total lumens.

Here you can find some nice calculators to help you.

i have an idea.can i use a 80 degree reflector in combination with my lens to collect whole light?is that a good idea?

No, that won't work (using parabolic reflectors). An elliptical reflector could work, but nobody really does that. A dual-lens system definitely works if you do it correctly.

[xevious (Gary)]

@JasonWW

Here is a comparison I did using the xhp-70. The dome and die size is the same for 70.2, so I would expect the same difference in diameter. (The 70.2 has less donut hole shape)

.

Interesting how “dome off” makes the flag stand at attention.

De-domed is a bit brighter & cooler with less spill and there’s a doughnut hole. I think I prefer domed, taking trade-off of brightness for warmer, smoother beam and greater spill.

[JasonWW]

@xevious

@JasonWW

Here is a comparison I did using the xhp-70. The dome and die size is the same for 70.2, so I would expect the same difference in diameter. (The 70.2 has less donut hole shape)

.

Interesting how “dome off” makes the flag stand at attention.

De-domed is a bit brighter & cooler with less spill and there’s a doughnut hole. I think I prefer domed, taking trade-off of brightness for warmer, smoother beam and greater spill.

Don’t look at brightness, color or spill. The picture was taken on different days with different camera settings. The picture is just to show the hot spot diameter difference. Both have a donut hole pattern, but shaved dome makes it more pronounced.

[xevious (Gary)]

@JasonWW

Don’t look at brightness, color or spill. The picture was taken on different days with different camera settings. The picture is just to show the hot spot diameter difference. Both have a donut hole pattern, but shaved dome makes it more pronounced.

Ah, OK. Thanks for clarifying. A more prominent doughnut hole would drive me a little batty. I’m so used to nice solid hot spots.

[id30209]

Awesome stuff here.

[1stein]

Another time came back to this CRX’s masterpiece. Whoooa, maaaaan, you should call yourself “torchopedia”. Another time I’m stunned how comprehensive is the first post. Just awesome.
(sorry, I just had to share my thoughts)

[Nev]

He’s the man if you want the best glowy stuff made without getting a second mortgage to pay for it

[Barkuti]

Just dropped by. I'm here to say that the Osram CULPM1.TG pictures in the opening post seem incorrect, looks like the die area isn't properly set as it looks exactly like the CSLPM1.TG, only rotated. Being a 4040 emitter it should look 25% smaller both in width and height (versus the 3030).

Cheers ^:)

[CRX]

Good catch

[shreya]

I have to admire you. Very useful posts.

[andyleekw]

Awesome CRX, you are amazing. Really thank you for your great effort.

From Andy LEDSign Malaysia

[cleo_stary]

Wow…. I just can’t find any word to say how gorgeous it is !!!
Any way, thanks a lot for doing this…

[hodor]

Anyone know what this is? I don’t think it matches any in the OP.

[djozz]

anything lowish efficiency, poor-ish tint, chinese?

[Brinyte_Gavin]

Very helpful, Thank you very much.

[Rat]

Great job in doing this thread and updating it all the time well done.

Thanks

[Sirstinky]

@hodor

Anyone know what this is? I don’t think it matches any in the OP.

Maybe a fake xp-e2?

[djxpress]

is there a way to bookmark the first post?