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FAQs

LAS Questions

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  1. Why are both red and green lasers offered?

    • A green laser is brighter and typically provides a sharper focus and hence, more accurate measurements than the traditional red laser. There is no cost difference between the green and red optical modules, so it really comes down to user preference for the application. 

  2. Is there any way to measure how well lenses are aligned to one another using CalcuLens™ Assembly version?

    • CalcuLens™ Assembly will allow a user to measure 1 non-air-gapped lens (singlet, cemented doublet or triplet).  To measure a stack of lenses already assembled into a housing with air gaps between them, one would need our CalcuLens™ Inspection version software. 

  3. Is LAS capable of measuring the boresight on an infrared assembly, set up to look at transmission instead of the typical reflective measurements?

    • OATi can quite easily re-configure the system for boresight or beam deviation measurement by placing a collimated laser under the rotary air bearing and measuring the orbit of the laser beam on a camera above the rotary air bearing in transmission. We do this for three known heights above the air bearing to get the beam deviation. This would require a MWIR laser and microbolometer for the LWIR optics (likely germanium and or silicon). 

  4. Can LAS accurately measure TIR and tilt in multi-lens assemblies with focal points very close together?

    • It is a little more difficult to identify and resolve focal points of multi-lens assemblies which are less than 0.5mm apart. The best way to separate close signals is to use a higher NA objective with a shorter depth of focus. This along with a high dynamic range camera should permit separating the return spots by careful focus adjustment with minimal laser power. In some cases, it is not always possible to bring just a single return spot image into view for analysis by using the automatic "Capture orbit" program. But as a last resort (due to some loss of accuracy) a manual method is also available to capture a single return spot, then spin the air bearing about a third of the circle orbit, capture it again and spin another third of the orbit to capture a third point in the orbit. After these three points around the orbit circumference are captured, the entire orbit is defined, and from this both TIR and lens tilt are accurately calculated. 

  5. Can the software be purchased as a standalone item or is it only available with a purchase of the system?

  6. Can the software be loaded independently on a computer for computational analysis away from the system?

    • Yes, the CalcuSurf-3D™ is built on compiled MATLAB code and can be run independent of the system computer.

    • Still have a question?

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Profiler Questions

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  1. When considering whether a particular optic can be measured, is the limitation of the instrument the accuracy or vertical resolution?​​

    • ​The most important parameter for all metrology tools is ACCURACY. This requires extensive calibration, high-resolution encoding and temperature control. 

  2. Is there a known repeatability of QuickPro-3D™ Profiler system?

  3. If there is a request to accommodate a component beyond the maximum slope, can such a customized request be done?

    • Not with the current product. The maximum slope angle for QuickPro-3D™ is +/-45 degrees. It is possible to extend the slope sensitivity to +/-60 degrees on non-specular (optically rough) surfaces. The LAS-Profiler™ accessory (quick-attach option for LAS) has a tilted sensor (30 degrees to normal) which allows extended slop measurement up to 75 degrees. 

  4. If a component has extremely parallel surfaces, will the instrument be able to discern the difference between those surfaces or have trouble measuring?

    • (Assuming the part is optically transparent) This is not a problem. Indeed, the sensor can measure thickness of parallel transparent materials from 100 nm to 200 microns (for high resolution sensor) and from 500nm to 1mm (for low-resolution sensor). The sensor sees both front and back surfaces simultaneously for thickness measurement. 

  5. How does sampling rate affect the amount of time needed to measure a component?

    • The sensor measurement rate is 1kHz. The motion permits continuous X/Y moves from 1-micron sampling to 100-micron sampling. This translate to a lateral measurement speed from 1mm/sec to 100mm/sec. Assuming 10-micron X/Y sampling, a 10mm x 10mm flat surface would take (100mm2/10mm/sec) = 10 sec. Assume 50% duty cycle = 20 sec. 

  6. Does QuickPro-3D™ Profiler have the ability to measure surface roughness or can it only measure profile geometry (surface accuracy)?

    • Yes, QuickPro-3D™ Profiler measures both roughness and form. The user has full control over the lateral sampling as mentioned in another FAQ. Use 1-micron sampling for surface roughness or small features, and >50-micron sampling for surface geometry over larger areas. 

  7. What wavelength of light is used by QuickPro-3D™ Profiler?

  8. Are the working distances fixed as part of the product or can longer working distances be achieved for the QuickPro-3D™ Profiler?

    • The working distance depends on the numerical aperture (NA) of the sensor objective.

    • High-Resolution 5mm

    • Low-Resolution 16mm

    • The sensor cannot switch between the two. The customer must choose high or low resolution at the time of purchase.

  9. Can QuickPro 3D measure film thickness such as PTFE, transparent in Vis, ~18um Thickness? In other words, does it have the capability of measuring "thickness" instead of just the surface height?

    • Yes, the sensor provides both height (top and bottom surface) and thickness simultaneously (at 4kHz readout rate)..

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