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# Hello. I have some questions about Laser Pointers.

#### Rick_Sanchez

##### New member
Hey guys. I just joined this Forum. Please understand my bad English, since i am not a native English speaker.

I'm college student who's major is Information and Communication Engineering. So i'm kind of interested in these lasers.

Anyway, my friend just asked for help, cause he is re-building his own website for selling Laser Pointers.
He is very proud of selling the highest quality laser pointers in my country. and i find out that he defines his own unit of Laser Brightness. It's called 'Bright'
As his information, Since 'mW' cannot be the unit itself of the laser brightness, he made the unit called 'Bright'.

I'll get an example of this 'Bright' with his current selling item.

Laser light color : 532 nm (Green)
Laser light brightness* : 27 Bright
Output Power : Under 30 mW

*: It is written in my language. my friend is not good at English, and i just translated. If he's good at English, at least he would name his own unit as 'Brightness', not 'Bright'

However, that '27 Bright' is caculated with...
Output Power, Visible ratio, Visible factor. (Again, sorry for my bad English)
Output Power is 30mw, and Visible ratio is 1, and visible factor is 0.9

Visible factor here is, Only the Visible ray from the entire beam, like IR beam.
he's module can filter out IR about 99%, but just in case, he marked as 90%, so the 'visible facor' is 90%, since the 10% of the entire beam is IR.

So, let's calculate. 30*1*0.9=27

That's why he calls his selling module's Brightness as '27 Bright'.

Problem is... remember that i said about Visible ratio?
I asked my friend, then how about Purple? and he said it's like 140:1
So if Purple Laser's Output Power is 1000mw, with 90% of Visible Factor, that laser's brightness is approx. 6.4 Bright.

I remember that Green Laser has variation like 520nm, and purple is like 405nm.
There is approx. 130nm difference between 532nm and 405nm, and has SUPER SUPER different Visible ratio, then there should be at least notifiable visible ratio change between 532nm and 520nm. and i asked him again about this.

He's answer is "There is no big differences."
I was totally not able to understand this. so i asked him where did he get those informations.

and this is where he get those infos.

Am i the one who thinks there is a still noticeable change between 532nm with 520nm, still it's the same group in 'Green'?
More, 532's 'visible ratio' is not even 1.

This is the URL that he says it has small error when we use that calculator, so that's ONLY for reference becuase...

He says this URL's calculator shows different result. Still, even this is not trustable just like first URL.

If i put...
Laser 1 : 10mw with 520nm
Laser 2 : 10mw with 515nm

First URL's calculator's result shows Laser 1 is 1.16 times brighter than Laser 2
Second URL's calculator's result shows Laser 1 is 1.157 times brighter than Laser 2
(When calculated in Dot brightness, not beam. Beam shows 1.116 only at 2nd URL's calculator.)

Again, am i the only one who thinks 1.16 is just a rounded up number from 1.157, and both are still trustable number?

In conclusion...
1. That unit 'Bright' that my friend made, is it Trustable?
2. Is there any unit can tell only the brightness of the Laser Beam?*

* : My friend says it is almost impossible for individual seller to tell Laser beam's brightness with Lumen, or Lux.

+ since i am a newbie, and not able to post a Link. i attached calculated photo.

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#### diachi

##### Well-known member
First URL's calculator's result shows Laser 1 is 1.16 times brighter than Laser 2
Second URL's calculator's result shows Laser 1 is 1.157 times brighter than Laser 2
(When calculated in Dot brightness, not beam. Beam shows 1.116 only at 2nd URL's calculator.)

Again, am i the only one who thinks 1.16 is just a rounded up number from 1.157, and both are still trustable number?
1.16 is 1.157 rounded...

Can convert laser power and wavelength to some brightness value (like lumens) or just use mW like everyone else...

#### Cyparagon

##### Well-known member
My friend says it is almost impossible for individual seller to tell Laser beam's brightness with Lumen, or Lux.
Your friend is a fool. Literally making up his own units because he doesn't know how to use existing ones? Point him to your language equivalent of the following two articles that easily disprove him

#### Rick_Sanchez

##### New member
Thanks for the reply. If i am right, since nobody is using lumens in this place when talking about Laser Pointers, i have no idea how to say this to my friend. Everyone is using mW, and my friend does not want to use mW to show only the brightness of the Beam, since the beam itself includes non-visible beam.

I tried to find out how to calculate Laser Beam or Dot's Lumen, and my short English and mathematics skills cannot follow the level.
Are there any easy ways to calculate Laser Beam or Dot's brightness? I have Output Power(mW), Divergence, Operating Voltage, Current consumption, and wavelength of Laser light(nm).

+
Your Laser Discord's URL shows it's expired.

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#### Rick_Sanchez

##### New member
Thanks for the reply. I can at least understand that as English itself, but for me it is really hard to translate those things and tell other guys.

So i found out there is already translated Wikipedia. and this leads again, that individual sellers cannot calculate laser beam's brightness, since having no tools.

#### trephanation

##### Member
What on Earth did I just read ?

#### trephanation

##### Member
No, the concept of your friend's idea. Laser output is not measured in "brightness," it's measured in mW or W. If he wants to describe the "brightness" of the laser then he needs to wax poetic and be a salesman, not try to invent a new unit of measurement that only he uses when he most likely has no physics or electrical engineering experience.

It's not something that anybody else would ever pick up on, unless he includes details charts and explanations on his sales page. Stick to mW I think will be the definitive consensus, and advise your friend to get an LPM and to do some reading if he wants to sell lasers and not mislead people. One last question, what is your target customerbase?

#### Snecho

##### Well-known member
This is all a very...interesting idea, but has he considered that if there is someone willing to buy a laser, they are experienced enough to actually know what mW is in the first place? "Brightness" is completely redundant in this sense.

#### skijohn

##### New member
Lasers in lumens??? oh, that made my brain hurt...

#### Cyparagon

##### Well-known member
I understand that to the uninitiated, it seems counter-intuitive to assert that a 50mW green is brighter than a 200mW red, and that perhaps a different unit may make this concept simpler. Coming up with your own is just stupid - it's like coming up with your own language. If you have to go to the trouble of explaining your new language... well, you would have been better off explaining the original concept to begin with. There are several ways to measure brightness, and lumens is perhaps the most common. The problem here is people might see the 40 lumens that a 80mW green puts out and assume it's very dim... "because my 60W table lamp is 800 lumens". It is, nonetheless, a valid unit.

Lasers in lumens??? oh, that made my brain hurt...

Is it that you didn't read the links I posted, or they're too involved for you?

Maybe this will help. It's a lot easier than you think. Look up your wavelength in a luminosity table like this one, and multiply your laser by that field. This is stuff everyone learned at age 12 or prior. There are others with more granularity, should you need them.