Non-contact measuring | Non-contact measuring

Key Words: interferometry, autocollimator, measuring microscope, Profile projector, vision / video measuring, stereo microscopes, inspection microscopes

Definition:Non contact measurement eliminates contact between the workpiece and the measurement tool

TECHNOLOGY:

Non-contact measurement is most commonly carried out with optical / laser technologies (although there are other non-contact measurement methods such as ultrasonographic, capacitive and inductive). Examples of optical measurement methods include:

1. Autocollimator: use of collimated light to measure angular deviation
2. Profile projector: where measurement takes place on a projected, magnified image profile of the sample rather than on the image itself.
3. Measuring microscope with digital camera: where with the help of image analysis software, measurements are made on the captured image.
4. Vision/video measuring: unlike the options described above vision measuring is not restricted to the field-of-view and is the ideal option for automated high precision metrology tasks.
5. Confocal vision systems: for accurate Z-axis measurements
6. Interferometry: This laser-based technology requires a high resolution microscope, interferometer and appropriate software. It is able to resolve minute differences in surface characteristics (to the nanometre scale).

APPLICATIONS:

Non-contact measurement in metrology has the advantage that it eliminates the possibility that a workpiece may be damaged (deformed, scratched or contaminated) though contact with a measuring tool. This may be important, for example, when measuring soft, flexible materials or in contamination-critical environments such as semiconductor manufacture. Non contact measurement, especially using vision / video systems, can be an advantage when speed and precision are required. Automated operation, in addition, can eliminate operator error and can greatly increase sample throughput.

MICROSCOPE CONFIGURATION:

Nikon offers many solutions for non-contact metrology including its range of Nexiv vision systems (including an instrument specifically designed for confocal semiconductor applications), autocollimators, profile projectors and measuring microscopes such as the MM400/800 series. The MM400 and MM800 measuring microscopes offer many of the advanced functions of a vision measuring system when combined with E-Max software. Simple, non contact measurement does not always need a dedicated metrology system. The DS-L2 box, for example, is a stand-alone computer with an LCD screen attached to a digital camera on a microscope. It allows users to capture an image of a sample and to draw and measure lines on the image. NIS Elements image analysis software brings measurement capability to AZ100 and SMZ1500 stereos and LV series inspection microscopes.

RECOMMENDED SYSTEM:

Nexiv vision systems provide the ultimate in non contact measuring solutions. Exploiting Nikon's optical measurement technologies, image processing and automatic edge detection tools, Nexiv systems can measure an enormous variety of parts, and can carry out multiple measurements of complicated profiles. The NEXIV VMA-2520 offers multisensor capability (touch probe ready) to enable accurate measurement of areas inaccessible to optical technologies. Please consult your local Nikon representative for advice on the systems best suited to your needs.