Laser twin sensor for precision measurement and quality control

Citation

(1998), "Laser twin sensor for precision measurement and quality control", Anti-Corrosion Methods and Materials, Vol. 45 No. 5. https://doi.org/10.1108/acmm.1998.12845ead.017

Laser twin sensor for precision measurement and quality control

Laser twin sensor for precision measurement and quality control

Keywords Laser sensors, Measurement, Selcom

A new patented laser twin sensor using optical triangulation principles that is believed to be ideal for high accuracy and measurement applications desiring a high frequency rate such as measuring thickness of very thin coating, has been introduced by Sensors-95 b.v. of Heerlen, The Netherlands (Plate 4).

Designed for tight spots and demanding industrial applications, the compact and rugged Selcom/DynaVision Laser Twin Sensor (LTS) claims to resolve surface thickness variations as fine as 0.0071µm when averaged at 100Hz. It is capable of measurement rates up to 500kHz in real-life industrial settings.

Other benefits claimed for the new non-contact LTS include its small spot size of 30 micrometers in diameter, a large observation angle of 43° at stand-off, the ability to optimise contour tracking with sharp increases in object height and its capability to measure both on frosted and furbished surfaces. An internal feedback loop also automatically adjusts for differences in light intensity due to an object's colour or texture by varying power to the laser diode.

The LTS emits a single laser beam from a laser diode that strikes the object's surface, reflecting a spot through twin imaging optics onto two position sensitive detectors (PSDs). If the reflected spot on one PSD is obscured by a change in the object's surface, the other PSD will see it. Intensity variations within the laser spot are also compensated for by using the two PSDs and lateral sensitivity of the sensor is greatly improved as well.

Plate 4 Designed for tight spots and demanding industrial applications, the compact and rugged Laser Twin Sensor (LTS) is ideal for high accuracy and measurement applications

Applications include measurement of critical surfaces, reference thickness measurement, layer thickness, differential thickness measurement in various industries, differential profile measurement, imbalance measurement, alignment control, material deforming, amplitude measurement and numerous others.

Details are available from The Netherlands. Tel: +31 45 571 9300; Fax: +31 45 574 2500; E-mail: Sensors@Tip. NL. The USA. Tel: +1(248) 355 5900; Fax: +1(24*) 355 3283; E-mail selcominc.com. DynaVision is located on the World Wide Web at http://www.dynavision.com and Selcom at http://www.selcom.se. The Selcom Web site has links to the DynaVision site.