Optical measurement of 1 micron dimensional changes

[mclearg]

Which system will give me 1 micron (0.001mm) sensitivity, when using optics to measure dimension changes in tissue (biomedical) samples. I was thinking of using linear arrays but the minimum pixel size I can find is 0.004mm. I had thought of staggering 2 or 3 of these but this would be to wide for my sample length. Does any one know if masked shadow sensors would do this resolution?

 

[cev]

Resolution is a function of both the image array and the optical system. You will not find detectors much smaller than you have listed, but you can change your optical system to increase the magnification (or is that out of the question?).

There are plenty of other solutions, but they depend on the specifics of your application (signal level, temporal resolution, etc.). For example, you can scan a single linear array across your sample (requiring a lot of control and timing in the scan and acquisition).

I guess by "masked shadow sensor" you mean what I would call a "shadow mask." If you have tons of signal to throw away, you can use such a thing. From what you describe, I think a change in optical magnification would be more appropriate.

CV

 

[BlueBeam]

If you really want to see objects in a range of a micron (or at least with a good resolution of 1 micron) with ´normal´ optics you will have a problem. With all usual microscopy the resolution is (theoretically) limited to the wavelength of the illumination. Since visible light is in a range of ~400nm-800nm you are almost at the theoretical limit. In addition you will also encounter problems with the optics, because working with such magnifications means strange conditions for the working distance, the illumination etc. Conventional magnification will not work or give big problems, imho.
Maybe you should inform about special microscopy systems working with effects like interferometry, with laserlights (UV-range is usual for biomedical applications??) or similar things.
Good luck!

 

[drog]

Are your tissue samples alive or dead, or should I say can you afford to have them die? If so, have you considered SEM Scanning Electron Microscopy? Do a google search for David Scharf if you want to see some excellent sample SEM photos.

 

[TimSchmidt]

3D image correlation can measure dimensions (as well as displacements and strains) with micron or submicron accuracy depending on the field of view. For a 10 mm field of view, you would have about 0.3 micron accuracy. For a 30 mm field of view, you would still have about 1 micron accuracy.

 

[canyoncruz]

An interferometric system can easily resolve in the milliradian region. There are several "white Light" systems with demodulators that are available for OTC (optical coherence tomography) Similar system can measure suface imperfection on hard drive media and a pretty fast rate.