Chromatic Confocal technique uses white light that passes through a series of lenses with high degree of chromatic aberrations. Each wavelength will focus at a different distance creating the vertical measurement range. When a surface of interest is within the measurement range a single wavelength of the white light will be in focus while all others will be out of focus.
Only the focused wavelength will pass through the pin hole filter to reach the CCD spectrometer. The physical wavelength measured corresponds to a vertical position.
Laser Light Health Hazard Need for care of reflected light
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Change in wavelength of laser light affects results on the same sample
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Non significant "display resolution" Height & lateral accuracy fixed by objective used Complex accuracy calculations
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Alpha blending algorithms to combine layer by layer data for complex accuracy calculation
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Limited fixed field of view Inaccurate stitching algorithms for larger surfaces
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Data Acquisition speed 7900 Hz
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CHROMATIC OPTICAL PROFILER
S
SAFE WHITE LIGHT
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UNIFORM BROAD WHITE LIGHT SPECTRUM No effect of light intensity on results
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INDEPENDENT LATERAL & HEIGHT ACCURACY Any scan area at selected height accuracy
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NO ALGORITHMS Physical Wavelength Measured = Accurate Height
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NO STITCHING Continuous scannign of larger surfaces Accuracy constant across any measurement size
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50x FASTER High Speed Sensor 384000 Hz
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LATERAL RESOLUTION vs ACCURACY
THEM
Camera pixel size or display resolution size are often used as lateral resolution to impress clients. For these, complex algorithms
used to determine what is actually in focus, gives a very different story of actual accuracy especially on complex surfaces.
US
Chromatic Confocal lateral accuracy is determined by physics and directly related to the spot size of the light.