When thinking of optics you probably visualize lenses and glasses. These shaped and formed glass pieces are the traditional form, but modern optics is a relatively new field of science and engineering that has led to the creation of technologies such as lasers, LEDs, and image sensing.
As optical engineering has progressed, the materials used in innovative optical systems have also progressed. Many applications require hermetical sealing glass with metal. To be effective, both the metal and the glass must have similar characteristics. Optoelectronics, optical and laser benches, vacuum tubes, and power tubes are all dependent on precision glass to metal sealing.
The modern optical age began when scientists began experimenting with Pyrex and how it could be used for new applications in reflective optics in astronomy. The original Pyrex was made from borosilicate glass, a very heat resistant material, which produced a clear glass with low expansion. These characteristics made it strong, durable, and able to withstand high temperatures without warping or melting.
Sealing glass to metal was the next innovation for optical technology. Finding the right material was a challenge. To successfully join (or wet) metal and glass, the thermal expansion of the two materials must be closely matched so that the seal is solid as the materials cool. Engineers tried many materials and found a winning combination in controlled expansion alloys such as Kovar.
Today, when an optical piece is required, a component is machined from a controlled expansion alloy and then covered in glass and hermetically sealed so that the glass is not damaged. This process is used in the manufacturing of items such as night vision glasses or big screen projection TVs.
The developments in wetting glass to metal have enabled engineers to create advanced optical technologies for research, defense, space exploration, medical, and consumer applications. EFI is integrally involved with the industries that are developing and manufacturing innovative products. The controlled expansion alloys we stock are widely used throughout manufacturing for forming the hermetic seal between metal and glass that is required in high tech optics.