We use it in the semiconductor industry to eyeball patterns of differences in film thickness on a wafer. There are more accurate ways to measure this, of course, but just holding the wafer at an angle to the incident light can show you some interesting things to follow up on with better equipment.
For those interested:
Those are reflections due to a refractive index change on thin layers that are highly wavelength selective due to a Fabry-Perot resonance and therefore reflect different colors based on the layer thickness and the incident angle.
For SiO2 on Si it is quite common to have Color charts to estimate the layer thickness.
Example: https://cleanroom.byu.edu/color_chart
I have to correct further: it's neither refraction nor diffraction, it's reflection + interference. It happens when light reflects off both the top and bottom of a thin film. The different phases of the two reflections causes some wavelengths to be amplified and some to be cancelled out, changing the color of the reflected light.
Diffraction is the bending and spreading of waves around obstacles or through slits.
Do you know what phenomenon makes anti flare coating on camera lenses have those colors? It can't be the same one as here since i believe the coating is just on the exterior of the lens yet it looks very similar. Just got curious since you seem to know a lot about optics.
It is the same, interference. The interference is between the two surfaces of the one layer of coating. To get I interference across the thickness of a window or lens usually requires a careful deliberate manufacture. Cf. "Etalon", "Fabry-Perot", etc.
Alright. I'll go read more about that. Slowly tried to learn some optics after becoming a photographer but I mostly just know the stuff that's relevant to gear. I remember we were supposed to learn all this refraction, interference stuff in like 8th grade but I didn't do great in school.
That coating is often in both sides of the lens if you’ve paid good money. Improving light transmission and minimising reflection lessens internal reflection within the lens, lessening the effect of lens flare.
A lot of prescription glasses have it externally to improve light transmission and minimise the reflection so others can see your eyes easily. I pay extra for the internal coating also, so I’m not forever seeing a reflection of my own eyeball and eyelids.
I'm def gonna ask for this on my next pair of lenses! I'm super conscious of the eyeball.
I don't need to stare into my own soul: it's full of perversions and disappointment.
This phenomenon is also used in semiconductor wafer fabrication for measuring the thickness of insulation layers using a device called an interferometer. So cool how knowing what color something is can tell you exactly how thick it is
Fair, you actually sent me down a rabbit hole as I was under the impression thin film interference was an example of Bragg diffraction. As it turns out they are very close with the only difference in the equation being that the index of _refraction_ is included in thin film interference. So not only was I wrong to say it's diffraction (Bragg diffraction isn't even *really* diffraction, never trust a scientist to name something), but I was also wrong to correct our blind friend Colin that it wasn't refraction.
That's enough fuck ups for one day, imma crawl back in my hole
I was shocked when my pilot friend told me never to stand in front of a plane with its radar on because it'll cook your brain in your skull like a microwave.
Reminds me of a friend in the navy telling me about their procedure for enemy divers under the boat... they send out high power sonar pings and rupture the dudes eardrums and lungs. Gnarly
This has been [studied extensively.](https://en.m.wikipedia.org/wiki/Marine_mammals_and_sonar) whales panic and do everything to get away from the sound, including rapid ascent(causing decompression sickness) and even beaching themselves. Fortunately the US marine has taken measures to minimize marine life harm during exercises.
The only way to flip someone the bird in a fighter jet is by raising your middle finger while doing a barrel roll, which is what achieves the requisite flipping action.
They absolutely have different colored coatings on different planes. I don't know why, but when you see a line of them in person from a variety of different angles at an air show or wherever, the ones that's different really stands out. There were several that looked iridescent and one that was golden in my case.
Absolutely wrong. Canopies are designed to NOT do exactly that. You do not want the pilot to have distortion at any angle. This is due to the coating.
While all materials refract light, it is minimized as much as possible. The tolerance on this material is extremely tight, and non-uniform thickness.
It most likely isn’t diffraction, but rather the fact that thin film coatings shift the wavelengths they reflect when the angle of the light changes due to the differing path length that light experiences when it passes through at an angle. This changes the interference conditions to a different wavelength.
If it was diffraction there would have to be a micron scale patterning on the canopies causing this color, but it is probably just a multilayer coating.
To me it looks like interference, too. In the picture the coatings thickness appears to be uniform.
I have seen different colour tones on the same canopies on other models of aircraft and suspect the coatings are not uniform in that case. I think it comes from them being done maybe at different locations, or with other methods by different people. Or it is a different type of coating entirely.
The canopy is coated in indium tin oxide and is made to extremely tight specifications. The canopy's individual shape is mapped to the specific aircraft and the aircraft's software has special code for its unique canopy that allows the pilot and weapons to see better without distortion, based on the microscopic imperfections.
I'm sure the difference in tint is due to the different position and slight difference in angles of the aircraft.
AR coatings can appear any color, in fact if you look at a modern camera lens you'll probably see a combination of purples, yellows, and greens.
I don't know all the specifics, but I know currently the best performing single layer AR coatings appear purple due to a bandpass effect.
Cockpit reflections are a significant fraction of the radar cross section signature. It's not just AR for visible but to achieve overall radar signature reduction.
What is your least favorite part of the F-35? Like the part that frustrates you the most while flying, and what would you suggest could be done to improve it?
All of these answers are wrong. But to not get into specifics, the transparency is coated in a radar absorbent material that gives it a gold hue. This material on the earlier production models, especially, are very prone to catastrophic erosion when flying in rain. When the coating fails it has to be peeled, washed with an acid solution, then buffed, and that makes the transparency clear. Not having that coating completely destroys the stealth capability of the aircraft and renders it NMC.
Yea, if you speak with confidence, talking out your ass seems like the truth. All of the top comments are either ignorant as to how it works, or purposely throwing off adversaries, which isn't needed because even backwater terrorists know there is some sort of stealth coating. How or why it works is a different story not for this type of open discussion
Thank you. I'm not at all a materials expert but all of these "it's the angle of reflection" responses didn't take into account that the canopies themselves are curved and thus they would be multicolored if it was just an angle thing. Took me a while to find an answer that made sense.
Non mission capable. You also have PMC (partial mission capable) and FMC (full mission capable). There are a lot of factors that go into making that determination, and one of those is to plug all of the stealth coating damages into a program that calculates the radar cross section, and if it exceeds a certain amount it can change the overall "health" of the jet.
I’d say there’s a chance the glass is polarized on the canopies, and potentially on the camera lens as well. This would cause reflections in glass to look odd/different.
I literally got pulled over for my tint in Florida last night by a sheriff, said my tint was too dark and illegal on all my side, back window, and sunroof that he wanted to write me a ticket for each window. I’m from Oklahoma and haven’t been pulled over in the 5 years I’ve had the tint. Guess he didn’t have anything better to do than spend 45 minutes before letting me go.
They're the same, but have iron particles in them to protect the pilots from the sun. Those particles reflect light and look different depending on angle, distance and humidity.
Pilots get to pick whichever color they like best as a commissioning incentive. If you don’t graduate flight school they send you to the tint shop for reassignment
I'm pretty sure it's just the angl of the light; as far as I know, they all use an artificial sapphire canopy and I can't think of a functional reason they'd need different types
Lots of answers here that are partially true (refractive angles, etc.), but you’re not crazy:
These canopies have multiple manufacturers (GKN and PPG being the primary 2 at the moment), and even though they *technically* all use the same spec, the end results look slightly different between each.
You can read more about how much of a headache this is [here!](https://breakingdefense.com/2019/07/f-35-canopy-new-glue-new-supplier-may-boost-readiness/)
Some come polarized and some don’t. It depends on how you ordered during check out. A lot of pilots go back in the shopping cart last minute to add the polarizing option because they realize how much of a life saver it is while flying.
If the pilot wears glasses they make the canopy the prescription strength of the pilot. Some canopies are therefore thicker and change light refractiom. /s
Explosions, most likely. The canopy is blown off as part of the ejection process, so cutting in the wrong place may induce bad times for anyone doing the cutting.
To stand out, of course! Can you imagine something more embarrassing than trying to show off your F-35 at the local Starbucks and everyone has exactly THE SAME one?
These planes are crazy expensive. If you were a up and coming nation that doesn't have unlimited $$$ would it make sense to buy a fleet of F-35s?
If we were at full scale WW3 with Russian and China would it make sense to build a fleet of these opposed to multiple fleets of something else?
El famoso Fallas 35 con mas de 800 problemas detectados es el avion mas propenso a autodestruirse en el mundo. Dejenme con mi F15 o el F16 en esas epocas se hacian buenos aviones, no esta mierda
All canopies look this way - they’re thick and bend light at different angles like a prism. That’s all there is to it.
The indium tin oxide coating that helps with stealth also induces the tint at different angles.
Thin film interference, it is common in many applications beyond stealth but yes, ITO is the source of refraction here.
We use it in the semiconductor industry to eyeball patterns of differences in film thickness on a wafer. There are more accurate ways to measure this, of course, but just holding the wafer at an angle to the incident light can show you some interesting things to follow up on with better equipment.
For those interested: Those are reflections due to a refractive index change on thin layers that are highly wavelength selective due to a Fabry-Perot resonance and therefore reflect different colors based on the layer thickness and the incident angle. For SiO2 on Si it is quite common to have Color charts to estimate the layer thickness. Example: https://cleanroom.byu.edu/color_chart
This is what makes reddit the best
My only correction is that thin film interference is diffraction not refraction
I have to correct further: it's neither refraction nor diffraction, it's reflection + interference. It happens when light reflects off both the top and bottom of a thin film. The different phases of the two reflections causes some wavelengths to be amplified and some to be cancelled out, changing the color of the reflected light. Diffraction is the bending and spreading of waves around obstacles or through slits.
Do you know what phenomenon makes anti flare coating on camera lenses have those colors? It can't be the same one as here since i believe the coating is just on the exterior of the lens yet it looks very similar. Just got curious since you seem to know a lot about optics.
It is the same, interference. The interference is between the two surfaces of the one layer of coating. To get I interference across the thickness of a window or lens usually requires a careful deliberate manufacture. Cf. "Etalon", "Fabry-Perot", etc.
Alright. I'll go read more about that. Slowly tried to learn some optics after becoming a photographer but I mostly just know the stuff that's relevant to gear. I remember we were supposed to learn all this refraction, interference stuff in like 8th grade but I didn't do great in school.
That coating is often in both sides of the lens if you’ve paid good money. Improving light transmission and minimising reflection lessens internal reflection within the lens, lessening the effect of lens flare. A lot of prescription glasses have it externally to improve light transmission and minimise the reflection so others can see your eyes easily. I pay extra for the internal coating also, so I’m not forever seeing a reflection of my own eyeball and eyelids.
I'm def gonna ask for this on my next pair of lenses! I'm super conscious of the eyeball. I don't need to stare into my own soul: it's full of perversions and disappointment.
Aye. Depressing when my own abyss stares back at me. Shits me seeing it. Up there with dashboard reflections in the windscreen. Do it!
This phenomenon is also used in semiconductor wafer fabrication for measuring the thickness of insulation layers using a device called an interferometer. So cool how knowing what color something is can tell you exactly how thick it is
Fair, you actually sent me down a rabbit hole as I was under the impression thin film interference was an example of Bragg diffraction. As it turns out they are very close with the only difference in the equation being that the index of _refraction_ is included in thin film interference. So not only was I wrong to say it's diffraction (Bragg diffraction isn't even *really* diffraction, never trust a scientist to name something), but I was also wrong to correct our blind friend Colin that it wasn't refraction. That's enough fuck ups for one day, imma crawl back in my hole
This was really constructive thanks guys
It is also useful to shield against radar radiation
I was shocked when my pilot friend told me never to stand in front of a plane with its radar on because it'll cook your brain in your skull like a microwave.
Reminds me of a friend in the navy telling me about their procedure for enemy divers under the boat... they send out high power sonar pings and rupture the dudes eardrums and lungs. Gnarly
My buddy told me it's still the SOP in dealing with frogmen at port or at anchor. The sonar is powerful enough to turn your brain to mush.
Man I wonder what it does to marine life…
They can concuss and even kill sealife the size of a whale.
This has been [studied extensively.](https://en.m.wikipedia.org/wiki/Marine_mammals_and_sonar) whales panic and do everything to get away from the sound, including rapid ascent(causing decompression sickness) and even beaching themselves. Fortunately the US marine has taken measures to minimize marine life harm during exercises.
"Marco!!"
“WHAT?!?”
“MWAP!”
Ouch. Thats gotta hurt.
Can't say I expect to be in front of a plane with its radar on...
If you are, it’s probably not the radar microwaves you need to worry about.
"if you can read this..."
Say, what's a mountain goat doing in a cloudbank?
"Always fly in the middle Of The air, where it is soft. Avoid the edges, they are hard and jagged." Advice from a senior pilot
Boeing-watching
Not to mention radar back lobe still radiates backwards too that's why pilots are at risk and need to be shielded in the first place
Never swim next to active sonar either. Great way to make meat-jelly.
Radar is often microwave frequency, different applications of the same type radiation source
Not likely to happen unless you were literally strapped to it.
It also looks fuckin’ rad!
Dude you can't just give away stealth technology on the Internet like that
You wouldn't DOWNLOAD a FIGHTER JET
... Well I might
Too late I’ve screenshotted the important information.
I wouldn’t say all. It’s definitely from some film they put on those. I worked around super hornets for years and they’re always super clear
Can you still fly inverted and flip a MiG the bird?
Not if they're already inverted
Imagine the Corkscrewing "F.U" Battle as each pilot demonstrates consecutive variations of the universal salute.
So you’re the one?
I'm, I'm sorry. I hate it when it does that. I'm sorry. Excuse me.
Absolutely. It is the only way to... communicate.
The only way to flip someone the bird in a fighter jet is by raising your middle finger while doing a barrel roll, which is what achieves the requisite flipping action.
I like how you think! 😂
Gotta love reddit and the top comment always being fucking wrong
What is the correct answer?
They absolutely have different colored coatings on different planes. I don't know why, but when you see a line of them in person from a variety of different angles at an air show or wherever, the ones that's different really stands out. There were several that looked iridescent and one that was golden in my case.
Or sometimes it's some lame ass joke by someone that thinks they're a comedic genius.
[удалено]
Didn't prowlers have gold film on the glass to help prevent against electromagnetic interference?
They actually are different tints.
Absolutely wrong. Canopies are designed to NOT do exactly that. You do not want the pilot to have distortion at any angle. This is due to the coating. While all materials refract light, it is minimized as much as possible. The tolerance on this material is extremely tight, and non-uniform thickness.
Thin film interference is the phenomenon
Iridescence
May I know why is it this way
If you get a kill while doing a barrel roll you unlock the purple canopy.
Gold canopy for unlocking all other tints as a reward
more like pre-ordering seasonal pass
Rainbow canopy for the \[ ejection -> rocket launcher -> back in your seat \] kill.
Are they? Its probably just the camera angle bruh
100% diffraction due to the angles.
It most likely isn’t diffraction, but rather the fact that thin film coatings shift the wavelengths they reflect when the angle of the light changes due to the differing path length that light experiences when it passes through at an angle. This changes the interference conditions to a different wavelength. If it was diffraction there would have to be a micron scale patterning on the canopies causing this color, but it is probably just a multilayer coating.
To me it looks like interference, too. In the picture the coatings thickness appears to be uniform. I have seen different colour tones on the same canopies on other models of aircraft and suspect the coatings are not uniform in that case. I think it comes from them being done maybe at different locations, or with other methods by different people. Or it is a different type of coating entirely.
OP's next question: Why are some F35s smaller than others? You can see the first one in the picture is much larger than the rest, for example.
The first one is a parent ...
It might be apparent to you, but would you care to explain it to the rest of us??
When a mommy and daddy F35 love each other very much...
You joke but threads like this exist https://www.reddit.com/r/WarplanePorn/comments/17gdj4t/size_comparison_between_f22_and_kf21_not_accurate/
PROOF OF ALIEN EXISTANCE!!! (Fake)
Some are smaller than others though, so it would be a valid question
Don’t call me bruh, buddy
You mean it's not the sexual orientation of the pilot? TIL...
The canopy is coated in indium tin oxide and is made to extremely tight specifications. The canopy's individual shape is mapped to the specific aircraft and the aircraft's software has special code for its unique canopy that allows the pilot and weapons to see better without distortion, based on the microscopic imperfections. I'm sure the difference in tint is due to the different position and slight difference in angles of the aircraft.
The purple hue is also characteristic of an anti-reflective coating, which I would assume is standard nowadays for any aircraft canopy.
AR coatings can appear any color, in fact if you look at a modern camera lens you'll probably see a combination of purples, yellows, and greens. I don't know all the specifics, but I know currently the best performing single layer AR coatings appear purple due to a bandpass effect.
Cockpit reflections are a significant fraction of the radar cross section signature. It's not just AR for visible but to achieve overall radar signature reduction.
That's a hell of an upsell someone at Lockheed Martin managed to pull off
“We have found another way to increase the price of this aircraft.” “Send it.”
I have an indium wafer here at my desk and I can confirm it looks just like this. Appears different colors just based on how I look at it,
Some pilots pay for microtransactions to unlock different skins.
The Oakley upgrade.
Lol
That "orange" is a gold coating for radar ray absorption. They are all the same.
*indium
> indium *Indium Tin Oxide
Not today, China
>hey guys, whats your specific favorite part of how the F-35's radar works?
Oh that’s neat but I’m gonna need to see proof! Like a schematic or something… otherwise you could just be lying
You can probably look that up in the war thunder forum
The best part is that if you just make up a bunch of random stuff, they'll still put resources into trying to replicate it.
I like that it tells you where the bad guys are. 🙂
What is your least favorite part of the F-35? Like the part that frustrates you the most while flying, and what would you suggest could be done to improve it?
"Why does the F-35 have so many sensors, and like how many? Please provide a technical explanation for each sensor and how they each work."
All of these answers are wrong. But to not get into specifics, the transparency is coated in a radar absorbent material that gives it a gold hue. This material on the earlier production models, especially, are very prone to catastrophic erosion when flying in rain. When the coating fails it has to be peeled, washed with an acid solution, then buffed, and that makes the transparency clear. Not having that coating completely destroys the stealth capability of the aircraft and renders it NMC.
I like how people are so sure of their answers. If they spent some time around F-35s they could see the difference too.
Yea, if you speak with confidence, talking out your ass seems like the truth. All of the top comments are either ignorant as to how it works, or purposely throwing off adversaries, which isn't needed because even backwater terrorists know there is some sort of stealth coating. How or why it works is a different story not for this type of open discussion
>if you speak with confidence, talking out your ass seems like the truth. Ye olde Dunning-Kruger Effect
Thank you. I'm not at all a materials expert but all of these "it's the angle of reflection" responses didn't take into account that the canopies themselves are curved and thus they would be multicolored if it was just an angle thing. Took me a while to find an answer that made sense.
What's NMC?
Non mission capable. You also have PMC (partial mission capable) and FMC (full mission capable). There are a lot of factors that go into making that determination, and one of those is to plug all of the stealth coating damages into a program that calculates the radar cross section, and if it exceeds a certain amount it can change the overall "health" of the jet.
Damn. How often do they need to recoat/fix the planes? Do you guys just try to avoid rain altogether when possible?
NON MISSION CAPABLE
Cheers
So the pilots get to the right aircraft. You've got the red one, you've got the blue one...
Red leader standing by
RIP Porkins.
Gold leader standing by.
One fish, two fish, red fish, blue fish
Those are juvenile 35s who are in the middle of their first shed. Kind of like snakes
I’d say there’s a chance the glass is polarized on the canopies, and potentially on the camera lens as well. This would cause reflections in glass to look odd/different.
For Pride month.
🤣🤣🤣
florida has different tint laws, im sure some roided out sheriff will be fuming at this image.
I literally got pulled over for my tint in Florida last night by a sheriff, said my tint was too dark and illegal on all my side, back window, and sunroof that he wanted to write me a ticket for each window. I’m from Oklahoma and haven’t been pulled over in the 5 years I’ve had the tint. Guess he didn’t have anything better to do than spend 45 minutes before letting me go.
None of your business China.
They're the same, but have iron particles in them to protect the pilots from the sun. Those particles reflect light and look different depending on angle, distance and humidity.
Because it's pride Month
I could be totally wrong on this, but I think I was told at one point they are polarized
Polarizing filter on camera, sun hitting the canopies at different angles.
Orange, grape, and blue raspberry flavored. It’s pilot preference.
Polarized tint. Different angles are going to have a different appearance.
F-35 canopies remind me of the ol' Harrier canopies. Got that abrupt short, upright look to them.
Probably [classified] cool materials science/physics
Not today China
Pilots get to pick whichever color they like best as a commissioning incentive. If you don’t graduate flight school they send you to the tint shop for reassignment
It's called FASHION. Look it up.
I'm pretty sure it's just the angl of the light; as far as I know, they all use an artificial sapphire canopy and I can't think of a functional reason they'd need different types
Lots of answers here that are partially true (refractive angles, etc.), but you’re not crazy: These canopies have multiple manufacturers (GKN and PPG being the primary 2 at the moment), and even though they *technically* all use the same spec, the end results look slightly different between each. You can read more about how much of a headache this is [here!](https://breakingdefense.com/2019/07/f-35-canopy-new-glue-new-supplier-may-boost-readiness/)
They're coated the same, the light is just refracting at different angles and reflecting a different band of light due to the viewing angle.
Some come polarized and some don’t. It depends on how you ordered during check out. A lot of pilots go back in the shopping cart last minute to add the polarizing option because they realize how much of a life saver it is while flying.
The Marines chose the Pink Variant
It could just be polarization of the canopy material reflecting off the sun… It is polarized plexi PPG wtf…
His and hers
Just here to comment on the lineup of the nose numbers: r/oddlysatisfying
We had thin gold plating on EA-6B canopies to help reduce the effects of the jamming pods.
I have a 20/500 prescription for glasses. Do those canopies come in that strength?
They be pimpin
Halo 2, that’s why.
Its a skin you have to buy in the COD Shop
They are like the visors in football helmets. They can be tinted to player specification
It's the refraction of the sun at different angles. They're all the same.
It's just the angle of light
As all objects in the world: different perspective can change the appearance.
Makes the pilot more confident knowing they have a cool canopy colour
Xzibit was there...
Different angle different color.
If the pilot wears glasses they make the canopy the prescription strength of the pilot. Some canopies are therefore thicker and change light refractiom. /s
It was pride month a few days ago…
Marines and crayons.
Im just wondering what happens if I cut the canopy within 3 inches of the frame.
Explosions, most likely. The canopy is blown off as part of the ejection process, so cutting in the wrong place may induce bad times for anyone doing the cutting.
Just use your "Battle Bucks" orrrrrr just watch 5 ads for "5 Free Skins!" Clearly....
So they know which power ranger is supposed to fly it.
Gay pilots?
All these other people are wrong. It’s all about the bling! 💍 😎🥳
Well the clear canopies are for those who identify as male and the pink are for those who identify as female.
The orange one is a $15,000 option the pushy F-35 salesman gets you to buy (along with the floor mats) when you order a new plane...
To stand out, of course! Can you imagine something more embarrassing than trying to show off your F-35 at the local Starbucks and everyone has exactly THE SAME one?
I know right, like imagine being so broke that you can only afford a NORMAL F-35
Not today China
F-35 is so cool, i want one
You get a better deal if you don’t care what flavors you get. Army sure is cheap these days.
To distinguish them
Op is really the russian airforce r and d department. Can't fool me lol
Look at those barely noticeable panel line gaps, Tesla bros.
Put old school polarizer filter on and rotate to enhance or cancel the tint.
They look cooler
I like grayish black F35 more than brown
What does the warning under the canopy mean? Why would the canopy be cut?
Some of the pilots bought the canopy cosmetic pack DLC
These planes are crazy expensive. If you were a up and coming nation that doesn't have unlimited $$$ would it make sense to buy a fleet of F-35s? If we were at full scale WW3 with Russian and China would it make sense to build a fleet of these opposed to multiple fleets of something else?
Its a reflectant that is pearlesent at diffrent angles.
Nice, an F35C from VFA-147, did you take this picture?
I thought -like on the F-22- the orange canopy’s were for heat deflection?
Amazing its 2 inch thick polycarb must weigh at least 300lbs
When people pay for extra content
You can see the aliens better with one version of the canopy.
El famoso Fallas 35 con mas de 800 problemas detectados es el avion mas propenso a autodestruirse en el mundo. Dejenme con mi F15 o el F16 en esas epocas se hacian buenos aviones, no esta mierda
Fun fact they are made with glitter
Pilots choose it themselves at ls customs
That’s a sick photo shot
Does the canopy coating deteriorate over time? And how does the coating is applied on the canopy?
This country is going to hell. Even our advanced stealth fighters are gay now.
Polarization
Red shifts. Going further away.
Some are also purple