wau. the best explanation of this topic I was able to find on internet. And I spend a lot of time trying to find something at least close to this but this is real gold ! thank you very much !
Damn, that sucks bro But what kind of permanent damage? As in there is an image permanently burned into the tube? Or did it affect its light amplification strength
Thank you for this clear and well put together explanation. I'm currently saving for night vision and I like to understand how what I have works as well as just benefit from it.
Is it possible for extreme bright light source to damage the tube when it is off? In theory it should not, as no electron is generated by photocathode that will impact the phosphor screen, nor will MCP multiple the electrons which may travel backwards to damage the photocathode? How about light source entering from the ocular lens?
I suppose it's possible if you shine something like a 2W laser into the tube and start physically burning the photocathode. However, once the tube is off and the photocathode is completely drained of charge, it'll likely take insane amounts of energy to do any damage to the tube.
In gen 0+ to gen 2+ designs, the photocathode will generate electrons even when the device is turned off. Because it uses the outer photo effect. In gen2 tubes, that can lead to a image appearing on a tube that was recently used and is exposed to high light. Because the the capacitors for the fixed screen voltage will stay charged for a while. The photocathode can generate enough electrons to pass through the micro channel plate and light the screen that way. This is also aided by the photocathose passively amplifying the electrons which come with a high energy thanks to the acceleration distance in the gen2 design. In gen2+ this phenomenon requires even more light to occur. Up to S25 photocathodes, transparent photocathodes where the norm, Those can deteriorate from moderate light exposure when turned off. The metallic versions of the S25 photocathode are not so sensitive to that effect. But they are still physically very thin, so they heat up fast when exposed to very bright sources. That leads to what looks like bubbles under the glass. That type of damage stems from a small area expanding under heat and peeling off the input glass. Those bubbles may touch the microchannel plate and cause serious damage when the device is switched on. Gen3 tubes use a semiconductor photocathode, which output energy requirement is lowered by a layer of cesium ocide. They use the outer photo effect, so a external voltage bias is required to make them work. They are also thicker, and less sensitive to deterioration. So unless you look at the sun, the deterioration should be somewhere in the ballpark of equivialent solar panels. But I never tested that and don't know anyone who sacrificed a tube for such test. In general the main wear in a gen3 tube is on the microchannel plate and the phosphor screen. And that can be kept in check by the internal protection. It's wise though to not crank the gain up to max. unless it's needed. And not to expose the thing to sunlight even when turned off.
It is technically possible if the photocathode is exposed, as it is made of a photoconductive material (Se? Anything else?) but with no voltage emitted electrons are slow sooooo.... idk
Can you help me to undertand how ( if it isnt impossible because its built into the Gen1+ tube, if it is...) Disable the "Auto Brightness COntrol" or "Auto Gating?" on my ATN Viper Gen 1+ Night Vision Monocular.... Its so Dim even in a dimly lit room.. that it over dimms itself... it seems like the auto dimming feature is somehow to sensative, or stuck mostly on? I hope its on the circuit board... if i can figure out how to get the main casing open and access the board/tube thanks for this awesome video btw.!
Unfortunately I don't have one of those. However the tubes inside will have roughly the same performance as an Echo or NNVT tube. Check out the comparison video I posted for footage on how they perform in extreme low light.
![Chinese Autogated NNVT vs Photonis Echo | Are these NVG tubes any good? [4K]](/img/n.gif)
Amazing video!
Simple but very informative
Thank you! I'm honored to receive your feedback and am glad to have helped!
Great video! Simple but dense with useful information!
wau. the best explanation of this topic I was able to find on internet. And I spend a lot of time trying to find something at least close to this but this is real gold ! thank you very much !
And yet my ass still manages to permanently damage my tubes from quick second glances across street lights.
Damn, that sucks bro
But what kind of permanent damage? As in there is an image permanently burned into the tube? Or did it affect its light amplification strength
Thank you for this clear and well put together explanation. I'm currently saving for night vision and I like to understand how what I have works as well as just benefit from it.
Good explained, I hope u make more technical videos of NVG!!!!!
also the video was very helpful thanks
Love this explanation
Thank you for this
great video
Thanks!
Is it possible for extreme bright light source to damage the tube when it is off? In theory it should not, as no electron is generated by photocathode that will impact the phosphor screen, nor will MCP multiple the electrons which may travel backwards to damage the photocathode? How about light source entering from the ocular lens?
I suppose it's possible if you shine something like a 2W laser into the tube and start physically burning the photocathode. However, once the tube is off and the photocathode is completely drained of charge, it'll likely take insane amounts of energy to do any damage to the tube.
In gen 0+ to gen 2+ designs, the photocathode will generate electrons even when the device is turned off. Because it uses the outer photo effect. In gen2 tubes, that can lead to a image appearing on a tube that was recently used and is exposed to high light. Because the the capacitors for the fixed screen voltage will stay charged for a while. The photocathode can generate enough electrons to pass through the micro channel plate and light the screen that way. This is also aided by the photocathose passively amplifying the electrons which come with a high energy thanks to the acceleration distance in the gen2 design. In gen2+ this phenomenon requires even more light to occur. Up to S25 photocathodes, transparent photocathodes where the norm, Those can deteriorate from moderate light exposure when turned off. The metallic versions of the S25 photocathode are not so sensitive to that effect. But they are still physically very thin, so they heat up fast when exposed to very bright sources. That leads to what looks like bubbles under the glass. That type of damage stems from a small area expanding under heat and peeling off the input glass. Those bubbles may touch the microchannel plate and cause serious damage when the device is switched on.
Gen3 tubes use a semiconductor photocathode, which output energy requirement is lowered by a layer of cesium ocide. They use the outer photo effect, so a external voltage bias is required to make them work. They are also thicker, and less sensitive to deterioration. So unless you look at the sun, the deterioration should be somewhere in the ballpark of equivialent solar panels. But I never tested that and don't know anyone who sacrificed a tube for such test. In general the main wear in a gen3 tube is on the microchannel plate and the phosphor screen. And that can be kept in check by the internal protection. It's wise though to not crank the gain up to max. unless it's needed. And not to expose the thing to sunlight even when turned off.
It is technically possible if the photocathode is exposed, as it is made of a photoconductive material (Se? Anything else?) but with no voltage emitted electrons are slow sooooo.... idk
Yes, it has happened. Especially with the sun. Intense light can physically burn the photocathode.
Can you help me to undertand how ( if it isnt impossible because its built into the Gen1+ tube, if it is...) Disable the "Auto Brightness COntrol" or "Auto Gating?" on my ATN Viper Gen 1+ Night Vision Monocular.... Its so Dim even in a dimly lit room.. that it over dimms itself... it seems like the auto dimming feature is somehow to sensative, or stuck mostly on? I hope its on the circuit board... if i can figure out how to get the main casing open and access the board/tube
thanks for this awesome video btw.!
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Delete those comments with time stamps and links those comments are really dangerous when you click them
What
@@tonystarkunlimited7332 there were some spam comments with some links that are not good
Timestamp comments are local to the video
Hey could you review the agm global vision pvs 14 51 gen 2+ and make a ultra low light test would be awsome
Unfortunately I don't have one of those. However the tubes inside will have roughly the same performance as an Echo or NNVT tube. Check out the comparison video I posted for footage on how they perform in extreme low light.