Schott Tubing Enables Precision Cut-to-Size Encapsulation of Reed Switches

Reed Switch Glass from Schott enables the glass encapsulation of reed switches using special cut-to-size precision glass tubing. The fabrication of glass tubes is one of Schott’s core competencies and key developments in recent years have been focused on reducing dimensional tolerances as well as miniaturization.

Specially developed for the encapsulation of reed switches, the company’s 8516 reed glass tubing has diameters that range typically from just more than 1mm to more than 5mm. The tubing can be precisely cut to size depending upon the application requirements. Sections can be as short as 5 mm for truly miniaturized applications.

To ensure rim quality, all sections are slightly fire-polished at both ends. The tubing is considered is green due to its high iron content which permits particularly high IR absorption rates. This enables customers to seal the glass in their process absolutely contamination free by using light sources rather than flames. 

According to the company, all its high-precision cutting equipment has been developed in-house. Washing and packing in modern clean rooms ensures excellent cleanliness and direct usability in the customer’s processes.

Each reed switch has two electrically conductive metal contacts (reeds). The ends of these two reeds can be hermetically sealed into the opposite ends of the Schott glass tube. While the switch is open, the reeds do not touch each other and form a gap. An electrical circuit is created when a magnetic field causes the encapsulated contacts to close. Once the magnetic field ceases, the stiffness of the reeds causes them to separate again. Due to the hermetic encapsulation, reed switches are extremely reliable over millions of switching cycles. Another advantage is that they don’t consume power in stand-by mode. This sets them apart from semiconductor solutions.

End-use applications for reed switches are found in numerous fields. Automotive applications include brake fluid control, seat belt or crash sensors. Home appliance applications include switches for electrical appliances such as toothbrushes and water heaters. In semiconductor test equipment, reed switches guarantee loss-free switching of signals during test cycles. 

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