Electricity + Control March 2018

round up

INDUSTRY 4.0 AND IIOT

Eye for detail Concepts for increasing the geometrical resolution of thermo- graphic cameras have belonged to the state of the art of technol- ogy for years. InfraTec is now taking this one step further. With MicroScan, the company is introducing an option to quadruple the image format for a radiometric thermography camera used in the civil sector with cooled FPA photon detector for the first time. For models of the ImageIR high-end camera series, this means that images can be recorded with up to (2 560 × 2 048) IR pixels (5,2 Megapixels). Users profit from a greatly improved resolution of fine structures in the thermogram. Behind the function is a newly developed, fast-rotating MicroS- can wheel, which is integrated into the camera. It ensures that four different individual exposures are taken per wheel revolution, which are offset laterally by half a pixel each. These individual ex- posures are brought together in real time into a thermogram with quadruple image format. Each pixel in the image represents a gen- uine temperature measured value and not an interpolated image point. In this way, thermography achieves a new quality. Through the spatial oversampling of the MicroScan, images gain in quality noticeably. For example, creation of aliasing artefacts in the im- age can be prevented. All this is done not only precisely, but also

at enormous speed. How quickly this happens is shown by the example of the ImageIR 8 300 hp. If the camera is in full-frame mode with its (640 × 512) IR pixels, the MicroScan wheel turns much faster than 5 000 revolutions per minute.Thanks to such high speeds, users with MicroScan can thermographically analyse pro- cesses with moving measurement objects or changing tempera- tures. The technology is not only predestined for use in micro-ther- mography, but also for a wide variety of security applications. Enquiries: Email thermo@InfraTec.de

3 Solutions for Semiconductor Wafer Presence Detection

Laser sensors with dual mode capability like the Q4X from Banner detect not only chang- es in distance but also changes in light in- tensity from a stable background condition. This allows the Q4X to detect challenging targets such as clear and reflective wafers with a high level of accuracy. A laser distance sensor with dual mode can detect not only when the target is present within a certain distance, but also when it returns a certain amount of light to the receiver. For this to work, a stable reference surface must be taught, and the distance and intensity of the reference sur- face are recorded and used as a baseline. The presence of a transparent or reflec- tive wafer entering the sensing range of the beam alters the perceived distance and light intensity from the background condi- tion. The Q4X from Banner is also able to detect through a glass window without interference. 2. Photoelectric Sensor through Window Glass Another sensor that accurately detects challenging wafers targets is a retro-re- flective photoelectric sensor with a coaxial optical design. The QS18 with Clear Object Detection emits and receive light along a single narrow axis. This optimises the de-

Semiconductor wafers can be transparent or reflective, both of which can be challeng- ing for sensors to detect. Because of this, it is important to use a technology that can detect both types of wafers reliably. Sen- sor mounting can also be a challenge when detecting wafers in a vacuum chamber. Fortunately, Banner Engineering offers several solutions that can be used to relia- bly detect both clear and reflective wafers in a vacuum chamber.This article describes three technologies that can be used to solve this application. 1. Dual Mode Laser Distance Sen- sor throughWindow Glass The first type of sensor that can be used to detect wafers is a dual mode laser distance sensor mounted through a window glass.

tection of transparent wafers by dramati- cally reducing the risk of false detection from reflected light. Additionally, because light emitted and received travels on a single narrow beam, these sensors can see through a small ap- erture, allowing them to be used through a glass window for vacuum chamber appli- cations. Photoelectric sensors with polaris- ing filters will emit and detect light waves of a specific polarisation, ignoring all other light waves. This further reduces the risk of false detection caused by reflected light. 3. Vacuum Chamber-rated Fibre Finally, a fibre optic solution that is rated for use in a vacuum chamber can also be used to detect transparent or reflective wafers.With a fibre optic solution, the fibre amplifier is mounted outside of the vacu- um chamber. A special pass-through fitting with a vacuum-rated glass fibre mounted inside brings fibre optic light into the cham- ber. The fibre is the positioned so that the light shines towards a vacuum-rated glass reflector, detecting both glass and reflec- tive wafers that pass between the fibre and the reflector. Enquiries: BrandonTopham. Tel. +27 (0) 11 453 2468 or email brandon.topham@retautomation.com

30 Electricity + Control

MARCH 2018