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Anonymous Poster

Optical filter non visible light

04/20/2007 4:38 PM

do they make a filter that will allow non-visible light to be seen as well as visible light? the wavelength doesnt really matter for what i want to do. thanks

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#1

Re: optical filter non visible light

04/20/2007 5:43 PM

Are you asking whether they make fiber that will transmit visible and non-visible light?

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#2

Re: optical filter non visible light

04/20/2007 6:40 PM

What is your application? IR or UV?

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#3
In reply to #2

Re: optical filter non visible light

04/20/2007 7:48 PM

BrainWave, Have checked out the last posting on Future Energy Sources 1.9.2.2 Cold Fusion? According to the guest, he's figured it out and is fusing De2. Interesting, check it out.

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#4
In reply to #3

Re: optical filter non visible light

04/20/2007 8:25 PM

OK boss will co. out.

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#5

Re: Optical filter non visible light

04/20/2007 11:47 PM

"the wavelength doesnt really matter for what i want to do"

Then just use visible light and you don't need a filter.

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#6

Re: Optical filter non visible light

04/21/2007 12:53 AM

According to my understanding of a filter, a filter simply prevents a portion of the incident light energy from passing, while allowing other parts to pass. A red filter allows only red light to pass, while preventing the passage, either by absorbing or reflecting, the other colors of light.

To 'see' infrared, requires an active system that senses an infrared image and adds energy one way or another (night-vision goggles) to make the image visible. It's not just a filter.

A phosphor is a compound that absorbs energy and then re-emits a part of the energy with a lower frequency. If you focus an ultraviolet image on a thin layer of an appropriate phosphor, it could make the image visible, and since no active element is required, perhaps you could stretch the definition of a filter to include this.

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#16
In reply to #6

Re: Optical filter non visible light

04/23/2007 3:04 PM

so you could combine the UV image with another image such as that from a digital movie projector and using a phosphor film to absorb the uv and emit it as visible light?

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#7

Re: Optical filter non visible light

04/21/2007 1:18 AM

No.

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#8
In reply to #7

Re: Optical filter non visible light

04/21/2007 5:01 AM

Hole in one. Go collect your prize. Oh sorry can't find it's invisible.

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#9

Re: Optical filter non visible light

04/21/2007 1:38 PM

I ran across this one time while looking for something else and I thought it was interesting. It seems the eye is marginally sensitive to infrared it you can block out "visible" light. I haven't tried it, so take it for what it's worth.

http://amasci.com/amateur/irgoggl.html

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#10

Re: Optical filter non visible light

04/22/2007 11:54 AM

Google 'fluorescence`.

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#11

Re: Optical filter non visible light

04/22/2007 1:52 PM

<do they make a filter that will allow non-visible light to be seen as well as visible light? the wavelength doesnt really matter for what i want to do. thanks>

we have to THINK and Interprete your Q!

Is it:

'Equal attenuation for 2000 to 10,000 °A wavelength?'

If that is what you want ,then the answer is Crystal Quartz. Maybe Clear Diamond.May be Tourmaline in the polar pass direction.

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#12
In reply to #11

Re: Optical filter non visible light

04/22/2007 3:07 PM

Hi MUKULMAHANT

You just made me go back and re-read the original Q. As soon as I saw the word filter, my brain started thinking exclusion, so I read the Q as 'allow non-visible but block visible'. Now I really don't know what the OP wanted!

Dick

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#13
In reply to #12

Re: Optical filter non visible light

04/22/2007 9:11 PM

Hi dkw,

We are not alone!

As somebody said"If you can state the problem correctly--you have half solved it!"

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#14

Re: Optical filter non visible light

04/23/2007 4:57 AM

You can have a filter that will exclude visible light but allow other wavelengths to pass through, is that what is being asked? If this is what you want try searching for 'solar blind' filters.

We test photon detectors using such a filter by shining a powerful halogen light on them then seeing if they can detect the UV component of a cigarette lighter flame at about 10m distance.

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#21
In reply to #14

Re: Optical filter non visible light

04/24/2007 12:06 AM

A cigarette lighter gives off UV?! Is that true?

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#26
In reply to #21

Re: Optical filter non visible light

04/24/2007 3:22 AM

All flames will--more or less.

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#28
In reply to #21

Re: Optical filter non visible light

04/24/2007 5:14 AM

Vermin, as MUKULMAHANT said all flames give off UV. (I'm having to post anonymously for this one). The devices I work with are fitted to aircraft & detect the UV component in the flame given off by a shoulder launched missile then warn the pilot that something nasty may be on its way. The UV can be detected even if the background light level is high.

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#30
In reply to #28

Re: Optical filter non visible light

04/24/2007 8:03 AM

Guest I thought these detectors used IR not UV and discriminated against back ground by both the strength and wavelength of the IR. Surely UV would be swamped by sun light? Flares are used to decoy the missile. Yes/No?

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#33
In reply to #30

Re: Optical filter non visible light

04/24/2007 10:38 AM

Thats why you use the input filter, it blocks everything except the band of UV you are looking for.

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#34
In reply to #33

Re: Optical filter non visible light

04/24/2007 10:47 AM

Just as an afterthought to my last post, we're working in the far end of the near UV spectrum at about 250nm.

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#15

Re: Optical filter non visible light

04/23/2007 2:12 PM

I am the guy that posted the orginal question. i guess filter is the wrong word choice. honestly, i dont know a lot about wavelengths and other things to do with light. I am a MBA student in Nashville and am working on a project for my entrepreneur class. for my idea to work i need someway to allow you to see additional information that is embeded in the light from a digital projector using goggles, glasses or or some other mechanism. anyone without the glasses would just see the regular picture w/o the extra info. thanks for all your help and responses.

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#17
In reply to #15

Re: Optical filter non visible light

04/23/2007 3:46 PM

What you want to do is achievable. e.g., see response by sideshow above.

First, filters can transmit or block light as desired. Information may be found many places (for one Wikpedia.com). Melles Griot has some tutorials on optics and beamsplitters. A beam splitter is a type of filter which reflects some colors of light and transmits others. Other companies which sell filters include Newport Corporation and Edmund Optics.

Second, Movie theaters have had glasses for special effects. 3D images use them. Originally one eye saw red light and the other saw blue. The combined image was 3D. Technology moved into linear polarization and finally to circullarly polarized light. For this approach, one eye sees clockwise polarized light and the other counter clockwise light. Use Google or Wikepedia and look for Imax. Imax 3D pictures have been around for several years in Imax equipped theaters.

Third, binoculars and scopes exist which use multiple wavelength regions, as noted by sideshow. Military scopes use infrared (IR) night vision optics. Some of these combine visible and IR light using beamsplitter technology to combine the visible and IR light. The IR requires a separate lens and detector. The output of the IR detector can be combined with the visible light for a combined picture.

I don't know if you are writing a paper and just need to mention technology which will work, or if you must buy something and demonstrate the technology. The "military" like solutions can cost 30-40K USD.

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#18
In reply to #17

Re: Optical filter non visible light

04/23/2007 4:05 PM

I was actually the guest that wrote the original question, i registered to give me better access. I am in an entrepreneurship class for my MBA program and if the tech is available or can be made, i may follow through with my idea. it sounds like the phosphor film would be the way to go. at this point, though, i just need to make sure i dont have a fatal flaw in my idea. unfortunately, i don't know a lot about all of the technology, as my main focus is the business side.

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#20
In reply to #18

Re: Optical filter non visible light

04/23/2007 4:44 PM

'it sounds like the phosphor film...' The phosphor film would have to be in the special glasses in order for only the selected people to see the information. A phosphor film can only produce an image if the image is focused on the film. This means a lens (quartz or other exotic so it transmits UV) in front of the film, and another one to enable the viewer to focus on that close image. DON'T FORGET the dangers of UV EXPOSURE! Very painful and you would probably be sued!

I say forget any thought of UV!

Dick

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#22
In reply to #18

Re: Optical filter non visible light

04/24/2007 12:26 AM

How inconspicuous do the people that receive the extra information have to be? I could see using IR, but the people in the audience that can see it might stand out like sore thumbs.

There's lots of IR probably coming out of the projector. So that could be used. On the other hand, an IR laser diode of say 100 milliwatts and 1064nm frequency could project or scan additional info on the screen that non-IR equipped viewers would not see. As a viewer, digital cameras (or anything using a CCD) will show you the IR in their view finders/pictures as whitish-purple light. A few experiments might be in order here. Also, 1550nm is considered fairly eye-safe because of the way the human eye is constructed. I don't know if this frequency is too low to be detected by CCDs. You'd have to check.

There is a company on the web that sells "X-Ray Specs" that use CCDs sensitive to both normal light and IR, however, they sell them so you can look under women's clothing - polyester is transparent to IR. I ain't kidding. Check it out.

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#35
In reply to #22

Re: Optical filter non visible light

04/25/2007 9:23 AM

as far as inconspicuous the less the better. the people that would be wearing them would more than likely want to draw as little attention as possible. i think i am going to have to check out the x-ray specs though. i really appreciate all of the help you guys have given me on this thread. i have tried calling some businesses but once they find out i dont currently have a budget, the talks end. i will do some more research on 1550nm light and the laser diode. thanks!

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#37
In reply to #35

Re: Optical filter non visible light

04/25/2007 11:09 PM

This isn't exactly the way they looked the last time I saw them, but I think it might be the same company for X-ray glasses:

http://www.advanced-intelligence.com/goggles.html

A little more on the IR diode laser. Typically, you shine the beam on a pair of galvo-mounted mirrors (x and y). These mirrors are then driven by a computer to make patterns and writing on a wall or whatever. The mirrors move so fast, that the image seems still. No flicker, etc.

Good luck!

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#19
In reply to #15

Re: Optical filter non visible light

04/23/2007 4:28 PM

OK, now we are closer to understanding your project. As I understand it, the majority of viewers would have no glasses or their normal ones, while selected people would have special glasses to allow them to see additional information. Is that correct? I'm also assuming that all this information is to be produced by a single projector, with light reflecting off an ordinary screen. Is that also correct? Ordinary digital projectors use glass lenses, which absorb UV, so I don't believe they could project it. If they could, then everyone not wearing protective glasses would have their eyes in danger from exposure to UV.

The only way I can see for this to happen would be for the projector (or a separate one) to periodically add an extra image of very short duration between the normal images, like they did a few decades back for subliminal advertising in movie theaters. (didn't they make that illegal?) I don't believe current digital projectors are fast enough to send the extra signal. Even if they could, that image would have to be monochromatic (sounds like a separate laser projector) so the special glasses would filter out everything other than the special image. The people using these special glasses would have to have 2 good eyes, one eye seeing the normal image, and the other eye seeing the special image.

Good luck on your project!

Dick

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#23

Re: Optical filter non visible light

04/24/2007 2:17 AM

'it sounds like the phosphor film...'

I know a little about the fim which can be used for store potential image produced by x-ray, and developed by uv, as said above. it went currently several years ago. but now displaced by x - ray real time image intensifier.

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#24

Re: Optical filter non visible light

04/24/2007 2:41 AM

Another thing is modern p\eople use some security code build into a picture to get confidential goal.

you can see the picture, but it includes a secret. it can be read out by a special tool.

it can be tv pictre or ordinary one printed on paper as well.

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#25
In reply to #24

Re: Optical filter non visible light

04/24/2007 2:46 AM

Good question... Are you talking about showing the secret information to an audience or to someone viewing it on their private PC? If the later is the case, then it's a piece of cake!!!

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#29
In reply to #25

Re: Optical filter non visible light

04/24/2007 6:34 AM

maybe it is.

I was heard that some useful information encode and interlace into a picture to deliver it to others who can decode but other cannt read.

you are from silicon valley. must be a software specialist. so its a piece of cake.

try to explain more interesting about it. I shall learn some more.

how to do it?

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#27

Re: Optical filter non visible light

04/24/2007 5:09 AM

You can block out the normal visible light with filters to leave only the extra information but if you are using wavelengths that are outside of the normal human reception range you still won't be able to see them. You will need a CCD device or phosphor type device to see the information.

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#31
In reply to #27

Re: Optical filter non visible light

04/24/2007 8:56 AM

Could you explain the phosphor type device? the images or video that would be shown would be for the most part public, its just that only a few people would need the additional information.

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#32
In reply to #31

Re: Optical filter non visible light

04/24/2007 10:36 AM

Something like a night vision sight or image intensifier that has an input matching the wavelength you want to see. This would receive the image you are looking for, convert it into electrons & accelerate it towards a phosphor screen which would then give you a visible image.

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#36
In reply to #32

Re: Optical filter non visible light

04/25/2007 10:53 PM

IR thermal imaging camera can see in the dark night.

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#38

Re: Optical filter non visible light

05/01/2007 10:16 AM

what about some sort of bifocal type lense with an infra red strip at the bottom and normal lense at the top? woudl something like that work?

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#40
In reply to #38

Re: Optical filter non visible light

05/01/2007 11:48 AM

Again, you would have to receive the IR information with a camera of some kind (ccd, cmos, etc.), and send the image to a screen (LCD, etc.) in the glasses, which because it is so close to the eye, would require a lens to let the viewer focus that close. Even with today's technology, I think it will be bulky, obvious, and expensive.

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#42
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Re: Optical filter non visible light

05/01/2007 10:48 PM

Expensive? Yes. Bulky? Surprising not. They're out there on the web. I've seen them. However, it's amazing that their sales pitch is based on their ability to see under women's clothing because most synthetic fibers are transparent to IR. And the glasses seem normal enough so that you don't look like Dr. Cyclops.

For the price, you'd think they'd be selling them to a different niche market - laboratory work or something. I believe the last time I was at that sight, they'd jumped on the 9/11 bandwagon. "It's only patriotic to have these glasses and thwart the terrorists within our midst!" That sort of thing.

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#41
In reply to #38

Re: Optical filter non visible light

05/01/2007 10:38 PM

I think that an IR strip would just act as a filter. Unfortunately, to view IR (or UV for that matter) you need some sort of active device that changes the invisible light to viewable light.

Some companies do make IR active glasses that use CCDs and have an "almost" normal form-factor. I don't think they're cheap, though.

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#43
In reply to #38

Re: Optical filter non visible light

05/02/2007 7:07 AM

CCD detectors respond to light including visible and near IR.

Night vision optics consist of lenses which focus light on the detector. Followed by converting this image into visible light for a human to view. If you use the same concept, one CCD could have a filter in front of the CCD which transmits only visible. A second version could use a filter which passes visible and near IR.

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#44
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Re: Optical filter non visible light

05/02/2007 8:35 AM

If this is only going to be viewed by the selected few you could used just one CCD with visible information projected on to part of the surface & the non visible projected on to the remainder. I'm assuming here that the viewer who is monitoring the hidden information would already know what is in the visible stuff & would not need to pay too much attention to it.

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#45
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Re: Optical filter non visible light

05/02/2007 9:59 AM

I was assuming that the presentation was to be viewed by an audience of 2 types of people. One group who were to "see" only the visible light portion. And a second group who were to "see" the IR special information. If the IR viewers were not to stand out, then 2 sets of goggles would be needed.

One could even have 2 sets of special information at 2 IR bands. That way if both sets of viewers took their goggles off, something would be missing. Both need the googles, but more information would be viewed by th "far" IR group. I have not looked up IR LED's for projecting the information, but say 950 nm and 1050 nm for the 2 bands. Both in the near IR region.

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#47
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Re: Optical filter non visible light

05/03/2007 12:04 AM

950 and 1050 might be too close to get a good separation. Just a thought.

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#39

Re: Optical filter non visible light

05/01/2007 11:39 AM

Any source-sensitive dedicated CCD, will convert it's inputted signal into a visible pattern/matrix. SOHO for instance, converts to visible, sources ranging from infra, all the way to gamma, with Q (notch) variable for the required type of examination.

This, of course, calls for dedicated electronics.

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#46

Re: Optical filter non visible light

05/02/2007 10:49 AM

let me know what you guys think about this

http://www.freepatentsonline.com/20030095401.html

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#48
In reply to #46

Re: Optical filter non visible light

05/03/2007 12:16 AM

I think this may save you some time, trouble, and money. Just go here...

http://cgi.ebay.com/X-ray-IR-GLASSES-Infrared-SPY-CAM-goggles-ultrasonic_W0QQitemZ220108780816QQihZ012QQcategoryZ4660QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

If the link is too long, go to eBay and search on X-ray-IR-GLASSES. There's a bunch of them out there for about $20.00. Check it out.

As for the rest of you perverts, the world is weird enough already. We don't need you playing with these things!

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#49
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Re: Optical filter non visible light

05/03/2007 4:24 AM

Seen the link. You must be in love to associate this to the topic of the OP

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#52
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Re: Optical filter non visible light

05/03/2007 11:37 PM

No. If you use an IR diode laser to draw your extra info on the screen, these (I think) glasses would allow you to see in that part of the IR spectrum.

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#50

Re: Optical filter non visible light

05/03/2007 9:01 AM

just to let you guys know, i am not some tool that is just bugging the crap out of everyone for some useless knowledge. I am an entrepreneurship student at an MBA program in Nashville, TN and am trying to get the basis for my idea. thanks for all of your help and ideas, it has helped me out quite a bit.

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#51
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Re: Optical filter non visible light

05/03/2007 11:35 PM

Good luck! And for what it's worth, I don't think anyone here thought you were a tool. Be proud!!!

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#53
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Re: Optical filter non visible light

05/04/2007 4:12 AM

My sentiments exactly &, as with so many of the threads here, everyone ends up learning something new.

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