Mirror disk

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Mirror disk

Postby kareno » Fri Jan 13, 2012 9:06 am

I have been giving thought to implementation of a disk version of a mirror drum. This has actually been done using inclined mirrors near to the periphery of the disk (I may be wrong, but I think Hollis Baird - no relation - achieved this).

But if a mirror is strictly on a disk then it translates sideways before the light source as opposed to rotating before it. To turn translation into deflection I thought of the arrangement in the attachment. A collimated light source, such as from a laser, comes in from the right. A domed mirror on the disk sweeps in front of the beam. The changing angle of the mirror surface where the laser beam strikes causes vertical deflection.

I think a spiral of such domed mirrors would achieve horizontal deflection for frame scan too. Now I just need to find a source of small domed mirrors!
Attachments
Mirror disk.JPG
Deflection using translating mirrors on a disk
Mirror disk.JPG (23.94 KiB) Viewed 9050 times
kareno
 

Re: Mirror disk

Postby Harry Dalek » Fri Jan 13, 2012 1:16 pm

kareno wrote:I have been giving thought to implementation of a disk version of a mirror drum. This has actually been done using inclined mirrors near to the periphery of the disk (I may be wrong, but I think Hollis Baird - no relation - achieved this).

But if a mirror is strictly on a disk then it translates sideways before the light source as opposed to rotating before it. To turn translation into deflection I thought of the arrangement in the attachment. A collimated light source, such as from a laser, comes in from the right. A domed mirror on the disk sweeps in front of the beam. The changing angle of the mirror surface where the laser beam strikes causes vertical deflection.

I think a spiral of such domed mirrors would achieve horizontal deflection for frame scan too. Now I just need to find a source of small domed mirrors!



Hi Karen you can see some effects off the mirror on the flat here on my you tube site

http://www.youtube.com/user/039dalekmoo ... NWa0OY5cns

some where there in my list ...

i found for me the mirrors worked better on the drum but i didn't play around enough on the disc to get it working right but had some interesting effect of amplifing the image via reflections on the outer part of the disc...

Even took me ages to work out i was viewing the image at the wrong angle .

You might find the nipkow mirror one of interest just for what you might expect.Sorry the videos a bit crappy its all i had didn't convert well.

I tried my drum as tiny squares as i recalled but i was only using one luxeon and i don't think that was enough so worked with the full mirrors just angles of the mirrors as they rotated doing the angle changes ...the video of the nbtv test card in upright video is on my you tube site too so and a few others which might be of help too.

My daughter was given a birthday present a while or so back a box of toy plastic beads all different colours shapes so that might be some where to look for this sort of thing ,some time back i got 100 tiny round mirrors from a craft shop they might have something like that you want too ..

Good luck i will watch with interest.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Mirror disk

Postby gary » Fri Jan 13, 2012 2:00 pm

kareno wrote:Now I just need to find a source of small domed mirrors!


Ball bearings! works the same as a bead disk, except reflectively - will work with any point light source. Or am I missing the point?
gary
 

Postby kareno » Fri Jan 13, 2012 3:04 pm

Hi Gary,

I think ball bearings would work about as well as transparent beads (except the light source is on the viewer side of the disk). The light source would be roughly a point source, but not collimated or it would only be reflected in one ball bearing. The spacing between the bearings would be quite large compared to their size, as per a bead disk.

Actually, what I had in mind was collimated light as from a laser, the reflections of which could form an image on a ground glass screen. You could potentially get a very big image from a very small disk. For this arrangement I would have the ball bearings touching each other such that as the laser beam left one bearing it would move onto another.

I did think of those chromium plated screw caps used on bathroom mirrors as dome reflectors for a disk. But they're not optically very good and they're not cheap!
kareno
 

Postby Harry Dalek » Sun Jan 15, 2012 6:42 pm

kareno wrote:Hi Gary,

I think ball bearings would work about as well as transparent beads (except the light source is on the viewer side of the disk). The light source would be roughly a point source, but not collimated or it would only be reflected in one ball bearing. The spacing between the bearings would be quite large compared to their size, as per a bead disk.

Actually, what I had in mind was collimated light as from a laser, the reflections of which could form an image on a ground glass screen. You could potentially get a very big image from a very small disk. For this arrangement I would have the ball bearings touching each other such that as the laser beam left one bearing it would move onto another.

I did think of those chromium plated screw caps used on bathroom mirrors as dome reflectors for a disk. But they're not optically very good and they're not cheap!


Hi Karen

Thats an an interesting idea ! i see in your drawing you would you have the ball bearings staggered ...you could have a very small drum ..

Are you going for 60 line since it would not be much of a drum anyway in fact tiny ...

only thing going small is the alignment but i suppose using a template line for a Nipkow the screw line from a print out it would be easier .

I think you could use it as a drum or a disc mmmmm thats new the drum might keep things smaller but .

Keep us informed on the progress !

one thing they would have to be pretty shiny you loose a lot of laser off metal and it doesn't reflect the light as well might be ok for ball bearing type nipkow thing but i don't think metals great for lasers .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Mon Jan 16, 2012 6:13 pm

Hi karen

I found these domed nuts they are metal and you can get them pretty small..i noticed them holding my tool box lid handle on and they are very small .

One thing i didn't think of or try but it comes to mind ..is seeing if a laser reflects off an LED the plastic may do it ,glass plastic and mica reflect and let the laser pass .... the red almost black IR ones look mirror like but i am not sure how they would go.

An led would be a cheap way to go .....since i wrote this i tested red clear and black they seem better for direct view than reflecting ...

i have one other idea that is cheap not sure how long they would last but
the round shiny balls used on cakes !
Attachments
nut.jpeg
nut.jpeg (5.58 KiB) Viewed 8953 times
cake.jpeg
cake.jpeg (3.34 KiB) Viewed 8946 times
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby kareno » Wed Jan 18, 2012 10:10 pm

Hi Harry,

Thanks for the domed nut suggestion. I think they actually might work because I recall one in which I could see my reflection (for once, a mirror that doesn't crack!)

There is a hobby shop chain in the UK that sells shiny beads too - I'll buy a pack of those when I'm next in there and see what they might do.

Best,
Karen
kareno
 

Postby Harry Dalek » Thu Jan 19, 2012 12:34 am

kareno wrote:Hi Harry,

Thanks for the domed nut suggestion. I think they actually might work because I recall one in which I could see my reflection (for once, a mirror that doesn't crack!)

There is a hobby shop chain in the UK that sells shiny beads too - I'll buy a pack of those when I'm next in there and see what they might do.

Best,
Karen


Hi karen

One good thing on the domed nut butting them up due to the flat nut part might make it easier .

One thing also Karen the lasers dot tends to be to large you'd want it pretty fine ,my lasers have a screw adjustment to the lens ..but the price you pay for a smaller dot is a different focal length .

You can also do this with a lens so if you have a nice collection you can test them what works best .

Let us know how you go .

I have got the itch my self to do some thing new, a monitor a year keeps the doctor away ( the brain ticking ) :roll:
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Harry Dalek
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