Livingston, Scotland, March 1, 2004. Scalar Technologies Ltd have announced the first in a family of advanced, in-line measurement systems targeted at process automation and control. The systems are based on advanced optical techniques and are used for measuring the thickness of transparent films and coatings.
The first member of the family, ScalarGauge I-50, combines advances in modern optics and electronics to produce an in-line system with performance normally confined to laboratory instruments. The system uses broad-spectrum reflection interferometry in the visible and near infra-red region, specially adapted to suit production line conditions. It operates in conjunction with an integrated, high performance scanner, designed to mount on coating/converting machinery and comes complete with a software package that provides comprehensive features including Profile and Trend measurements. Being an optical device, ScalarGauge I-50 produces extremely accurate measurements without touching the product to be measured.
In many instances, the system will simultaneously measure multiple layers, a feat beyond the scope of traditional, in-line measurement techniques. Calibration, often a headache in setting up and maintaining in-line measurement systems, is unnecessary. The system is factory calibrated during manufacture and no further calibration is required during the lifetime of the instrument. This is due to the instrument design and the precise nature of the manufacturing process. Installation is also straightforward and the sensor is relatively immune to web flutter and machine vibration.
The basic principle of operation is that of thin film interference. When light strikes a transparent film, some is reflected off the top surface and some will reflect off the bottom surface. These reflected light waves interfere with each other and produce an interference pattern, or interferogram. This pattern derives directly from the optical separation of the two surfaces, which is their physical separation multiplied by the refractive index of the material. By analyzing the interference pattern using a specially developed software algorithm, the film thickness is accurately calculated. Measurement accuracy is sub-micron, more than adequate for most in-line process control requirements.
Data are recorded in a standard file format and available for export and analysis through the Ethernet port. Interfacing using standard Ethernet (TCP/IP) connectivity, means that the system can be accessed from anywhere within the corporate enterprise network or even via the internet for remote monitoring. The process control system also contains an interface to commonly used external signal functions such as Reset, Unwind, Rewind, Tachometer (machine speed) and provides Warning and Alarm level output signals.
There are a number of sensor options available, to optimize performance for a specific application. In general, two sensors cover the majority of applications. One version is capable of measuring layer thickness between 0.5um and 100um and there is a reduced cost sensor, with a limited measuring range of 0.5um to 50um.
This system has been developed for the plastic film and converting industry, for in-line measurement of base film thickness, release coatings, adhesives, transparent lacquers and hard coatings. However, if the sensor is mounted on a robot arm, the system can measure coatings on formed shapes or piece parts, such as car headlamps. Measurements can also be made on coatings applied to semiconductor wafers and optical components.
For more information, visit www.scalartechnologies.com .
Laser Focus World