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Robonz wrote:In my opinion 3D printing is never going to have a mirror finish even with an acetone treatment. The coating method that is used to give a mirror finish on plastic parts is called vacuum metalisation but the surface needs to be dead flat before you start.
Being the optimist I think you could adhere some very thin acrylic mirror to the 3D printed parts. Andrew, if you give me the dimensions I will cut and send you 40 mirror strips that are 1mm thick rear surface mirrors so you can have a play. They have an adhesive backing too. Free of charge of course! Let me know if you want them.
Cheers
Keith
albertMunich wrote:Not a large scale TV set but probably a misfired attempt to create a windmill----I never saw it make a single turn....though we had some strong winds today....
Harry Dalek wrote:Just posting this up as i have never seen a mirror screw have a reflector used with it .
ppppenguin wrote: Why didn't mirror screws catch on for TV? Probably too much high precision engineering when compared to CRT based solutions which were improving all the time and more amenable to mass production.
Panrock wrote:Wow, some fascinating attachments there! Yes, I did lay on polarised light for my Kerr cell, with crossed polarising films on each side.
Another method of light modulation to try, Harry, might be the 'speaker' method. Use a small 3-inch speaker say, and glue on a cardboard strip sitting at right angles to the cone and bottom edge cut to mate with it. At the top edge there is a small V-shaped notch. This is set against a stationary edge (another piece of card) and bright DC light shone through the resulting tiny triangular hole. The moving speaker cone then modulates the light.
The higher the modulating frequency, the less the excursion of the cone that carries the same power. But to compensate, the less the excursion (if things are set properly) - the closer the hole is to the point of the 'V', so the more the modulating effect.
One problem I can see with this is that on bright scenes the pIcture definition would be worse. The picture gamma would be determined by the angle of the 'V'. In addition you could experiment by replacing the flat edge of the stationary card with a curve or even another 'V'. Or use two facing speakers and moving, meeting, V's to double the effect.
Just a half baked idea I've never got round to trying. Maybe you have?
Steve O
Harry Dalek wrote:It makes me wonder if you pointed a PMT at your mirror screw could you make a mirror screw camera ? would you need a slit mask as the reverse for a monitor ..the PMT would have to be run low but i think it could be done ....have not come across a mirror screw camera reading but you could have a first Steve .
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