Question on range finder lasers

[laquishabonquiqui]

Hello, I have a question on how range finders use their lasers. Does the recieving part of the range finder recieve a single beam of light somehow perfectly reflected from an object or does the laser refract in all directions (when it hits an object) at a certain frequency to be recieved at that frequency?

Thanks

[Sensei]

Each laser distance meter has mentioned on the box to which range they are accurate.

On eBay people selling them even mention it in the title of auction.

Edited May 8, 2017 by Sensei

[Lord Antares]

Each laser distance meter has mentioned on the box to which range they are accurate.

On eBay people selling them even mention it in the title of auction.

 

He is asking how the laser measures the distance and sends it back to the device.

 

You are correct in your first assumption. It reflects the laser beam back perfectly as it reflects straight back if done correctly.

 

''The most common form of laser rangefinder operates on the time of flight principle by sending a laser pulse in a narrow beam towards the object and measuring the time taken by the pulse to be reflected off the target and returned to the sender.''

 

https://en.wikipedia.org/wiki/Laser_rangefinder

[studiot]

 

He is asking how the laser measures the distance and sends it back to the device.

 

You are correct in your first assumption. It reflects the laser beam back perfectly as it reflects straight back if done correctly.

 

''The most common form of laser rangefinder operates on the time of flight principle by sending a laser pulse in a narrow beam towards the object and measuring the time taken by the pulse to be reflected off the target and returned to the sender.''

 

https://en.wikipedia.org/wiki/Laser_rangefinder

 

Good answer +1

 

There is one thing about these devices, they are indiscriminate.

So it is difficult to be certain what you are pointing them at.

You have to be careful the received reflection (OP note not refraction) is actually from the object of interest.

This is where dedicated reflector types have the advantage, but obviously you have to be able to access the target.

[DrP]

Quote: "have to be careful the ... reflection is from the object of interest"

 

I used to use a laser range finder for golf and yes, you have to have a steady hand to avoid getting a range from the trees in the background... You can quickly check this though by aiming at the large target in the background so you know if your measurement to the flag is the same you have missed it and actually hit the background.

[Strange]

You are correct in your first assumption. It reflects the laser beam back perfectly as it reflects straight back if done correctly.

 

 

 

That doesn't sound right. It would only reflect back "perfectly" if it were reflected from a mirror.

 

In most cases, it will be mainly diffuse reflection. In other words, the light will be reflected in all directions. Which is why someone standing to the side can see the laser spot! And why it will work with an surface that is not perfectly at right angles.

 

But, the detector does pick up that small fraction of the light that is reflected straight back to the range-finder. (Which I guess is what you meant.)

 

I'm not sure I understand the OP's second option, though...

[Lord Antares]

Yeah, that's more correct.

 

The light that IS picked up by the range finder is reflected back perfectly, but the light from the laser will be reflected in all directions, generally speaking.

 

 

I'm not sure I understand the OP's second option, though...

 

He was just guessing.

[studiot]

Actually corner reflectors are used, not mirrors, if you want strong reflections.