Can circular grooves of CD/DVD be replaced by straight grooves as shown in the picture, by standard CD/DVD ROM manufacturing machines with some non-permanent tweaks? Can the grooves spacing be modified?
It could find a great application in diffraction gratings.
Thanks
Hello,
the answer is: yes - provided that ...
CD/DVD production is about heating/pressing a quantity of PC between die plates. So if you can get die plates patterned according to your needs, this is doable. Just mount your own die plates and start production.
Quite another question is whether you can get the die plates: standard die plate manufacturing will certainly rely on a rotating die and a simple linear bearing for the laser (as this is a quite simple mechanical setup). Whether the writing process can be modified to produce your line pattern on the rotating medium is a question to be answered by those who are manufacturing the master dies.
Or you may find another way to get your pattern written to a raw DVD die. Still a bit of search to do.
I can add to the previous answer that in some cases DVD or CD disks without any modification can be used as a diffraction grating. In our university it is often used for studentical laboratory works. It is very cheap and simple
But he needs a linear grating, instead of the radial grating that a DVD/CD is
The master form certainly has to be made somewhere else, not with DVD technology. But the replication by pressing and subsequent metallization can be done with standard fabrication technology I suppose. But there are specialized firms for mastering and replication of optical gratings and microprisms in plastics too.
Hi Alexander, thanks for your input. Could you please link me to the firms replicating gratings in plastics? My main motivation is to lower the price. If I can get low cost gratings ready-made it would be great.
@U.Drehar : I also want to know about concave gratings. Can those, too, be manufactured same way? And I think the process isn't that simple. I guess cooling rate, etc have very important contribution to the groove replication. Could you please refer to any particular literature where techniques about precision injection molding are described.
Thanks
Ultimate aim: To produce good quality reflection concave diffraction gratings.
First goal: To make Blazed plane diffraction grating.
The efficiency of the holographic grating films is too low to be used in any analytical device.
Hello,
I did a bit of googling and came up with the following:
http://www.google.com/patents/DE4340106A1?cl=en a German patent application regarding the production of non-planar diffraction gratings with quite a number of references to literatue and other patents.
http://www.zeiss.com/spectroscopy/en_de/products/gratings/concave-gratings.html#downloads
some information from a commercial vendor - ZEISS. You may already know that - anyway ...
Hope this satisfies your needs.
I'm agree for half ton... You can see, for example:
DIY Spectrometer, and notes on online Spectral Workbench
http://saisa.eu/blogs/Guidance/?p=1065
or:
https://publiclab.org/wiki/spectrometer
Good luck!
DVD is necessary? There's also an option to write LightScribe Discs even though they'Ve been discontinued. With the correct raw-disc I could imagine to write a reflective grating as well..
Also have a look here: http://www.instructables.com/id/Burning-visible-images-onto-CD-Rs-with-data-beta/
Would LightScribe capable of printing such fine lines? That would depend on the grain size of the photoresin on the printing side. Is there any literature/previous work on this?
That's something new to me. Thanks.
(Reflective) diffraction gratings depend on the differences in height of the lines.
LightScribe does not alter the surface - just the color of the surface. (BTW: this change in color is - to some extend - reversible.) You may try it out, but you won't find a diffractive effect.
Regards
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