Electrostatic Discharge (ESD) Protection mechanisms are essential to any application that interfaces with the outside world, ranging from consumer,and industrial to medical markets. This is because the phenomenon threatens the majority of electronic systems around us, particularly with advances in the use of portable devices and as applications become further integrated.
How does it work?
ESD is characterized by the rapid discharge of a finite current between two bodies with a high potential difference. In this way, a device such as a microcontroller could become inoperable within nanoseconds without sufficient ESD protection.
Triboelectrification is the process by which two given bodies would come into close contact, rub against one another and separate. The resultant charged particle transfer creates an imbalance in polarity. This leads to high currents between relatively short distances, making a high voltage impedance across the air medium. These high current densities and electric fields cause ESD strikes, permanently damaging the involved electronic devices. The high energy of such currents can melt away the targeted regions of vulnerability, typically thin conductive films or transistor components.
One of the primary problems with the phenomenon is the difficulty in identifying the source of the resultant malfunction due to the small time frame. A typical work environment could be anything from someone jingling coins in a pocket near electronic equipment to using a standard office chair. What's worth bearing in mind with ESD is that individual events are not discernible and carry negligible risk in isolation. The sheer multitude of strikes, though, exacerbates the issue and increases the likelihood of a high-magnitude strike occurring within a given period.
ESD in Barcoding and Data Capture
When selecting a barcode reader, careful consideration should ensure that it does not introduce additional risks regarding ESD events. Printed circuit boards, semiconductor wafers, integrated circuits, and other electrically sensitive components typically use small high-density barcodes to conserve space, making it difficult for some readers to scan them from a distance. When proximity scanning is employed, the barcode reader may build up static charge depending on whether it is used on a non-conductive surface. If the reader itself has built up aggression and is brought close to a sensitive component, an ESD event could occur, which may permanently damage the part.
The damage from electrostatic events contributes to more than 25% of failures in electronic devices returned for servicing. Protecting against such damage can save the company significant time and money in repairs or replacements while maintaining a customer's confidence in the quality of service and the products themselves. Such events are prevalent in a host of other applications which involve data capture:
Preventing ESD damage during the manufacture and operation of sensitive medical equipment is very important in the healthcare industry. Such detrimental processes are a potent source of electromagnetic interference (EMI). This is not just electronic equipment but metal surgical instruments nearby.
Logistical tracking of products through scanning barcodes located on the packaging. A sufficient charge can develop from the exposure to the barcode reader, other charged packages, and surfaces within freights and heavy goods vehicles. When on the go, service members will not usually wear ESD protective gear or consider it a potential hazard, so the equipment should be well-grounded.
Warehouse environments, which stockpile electronic goods and utilize barcode scanning for inventory management (including healthy check-in/checkout), risk having ESD-related damage incurred on the objects themselves or the warehousing equipment involved.
Retailingsetups, particularly with dry and cool climates, are vulnerable to rapid charge build-up and transfer. Quick flow of goods at metallic checkout tills can induce a charge and malfunction poorly protected products before the transaction is even completed.