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Glossary

Glossary of Terms

Ambient Temperature
Refers to the temperature within an enclosed space (often room temperature).
Anti-Reflective Glass
Glass with coating applied to the surface to reduce reflection. This improves the efficiency of the system since less light is lost.
Battery Seal
A high conductivity terminal pin is sealed to a metal battery cover using a particular chemically resistant glass for lithium batteries (rechargable).
Bioactive Glass SCHOTT Vitryxx®
A fine glass powder with an amorphous structure (like all glasses) consisting of elements which are found naturally in the body - calcium, silicon, sodium and phosphorous. SCHOTT Vitryxx® is used in cosmetics for its mineralizing, soothing, anti-oxidant and anti-bacterial properties.
Ceramic-to-Metal Sealing Technology
A sealing technology that connects special types of industrial ceramics to metal. Please refer to SCHOTT CerTMS® technology page for more information.
Ceramic-to-Metal Seals (SCHOTT CerTMS®)
A vacuum-tight assembly of ceramic with metal used to feed electrical conductors through the walls of hermetically sealed packages.
CerTO®
Metallized ceramic replaces the pins in a hermetic TO header.
Chemical Plating
A non-galvanic plating method in which electrical power is not used and whereby metal is deposited onto a conductive surface by several simultaneous reactions in an aqueous solution.
Cold Welding
A method of joining metals (such as aluminum) at room temperature by subjecting thoroughly cleaned metal surfaces to pressure; coalescence is produced solely due to the application of mechanical force.
Combined Plating
A plating method whereby different types of metal (such as gold, silver, tin and lead) are deposited onto a conductive surface. Well-matched plating combinations can be used to alter the functional properties of the metal surface, thereby reducing unwanted diffusion processes and improving adhesion and corrosion resistance. Please see this page for more information.
Compression Seal
A compression seal is designed to exert concentric compressive stress on the glass in the available temperature range, while considering the thermal expansion coefficients of the metal and glass. Please see this page for more information.
Cylindrical Type
Cylindrical quartz packages are used to hermetically protect high frequency quartz crystals. The product consists of a cap and stem with two lead pins. Please refer to our cylindrical quartz product page for more information.
Dental Glass Powder
Silicate glass powders and polyacrylic acid are used together for various dental purposes.
Desiccators
An air-tight sealable container with desiccanting agents (such as sulphuric acid) used for the purpose of preserving moisture-sensitive items such as hygroscopic chemicals from humidity.
Dielectric Constant
The dielectric constant is the ratio of the permittivity of a substance to the permittivity of free space. It is an expression of the extent to which a material concentrates electric flux, and is the electrical equivalent of relative magnetic permeability.
DIPs
Dual Inline Packages (DIPs) are glass-to-metal seals with rectangular shape and two lines of pins along the opposite side.
Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (RoHS)
A European Union regulation effective since July 1, 2006 which sets the maximum concentration limits on hazardous materials used in electrical and electronic equipment. The substances are lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE).
Directive on Waste Electrical and Electronic Equipment Directive (WEEE)
Established in February 2003, the WEEE sets collection, recycling and recovery targets for electrical goods and is part of a legislative initiative to solve the problem of large amounts of toxic e-waste.
Dissipation Factor (DF)
The measurement of the rate of power loss of a mechanical mode, such as an oscillation, in a dissipative system.
Double Penetration
An electrical compression glass-to-metal penetration, with ready-to-install units consisting of two single penetrations in series.
Dry Pressing
Glass powders mixed with organic materials represent press-granulates that can be dry-pressed before sintering.
Electric Resistivity
The measurement of the degree to which an object opposes an electric current through it. The resistance of an object determines the amount of current through the object for a given voltage across the object.
Electroless Plating
A method of plating whereby electrons needed for the reduction of metal ions are supplied by a reduction agent that is present in the plating solution. This agent sets free electrons while being oxidized. Click on this page for more information.
Flatpack
Also known as a hybrid/ microelectronic package, a metal wall package or a glass-to-metal package, the term "flatpack" refers to the hermetically sealed packaging of electronic components in one rather flat container.
Lighting and Imaging
A fiber optic strand is designed to guide light along its length by confining as much light as possible in a propagating form.
Glass-to-Metal Sealed (GTMS) Package
Also known as a TO or hybrid/ microelectronic package, a metal wall package or a flatpack, "glass-to-metal sealed (GTMS) package" refers to the hermetically sealed packaging of electronic components within one container.
Glass-to-Metal Sealing Technology
A sealing technology that connects glass to metal. Please click on the GTMS technology page for more information.
Glass-to-Metal Seals (GTMS)
A typical glass-to-metal seal (GTMS) consists of an external metal part into which a pre-formed sintered glass element is sealed. The sintered glass element, in turn, encloses one or more metal leads that are sealed into it. Because of the different expansion coefficients of various glasses and metals, mechanical stresses during the melting process are inevitable. By adopting special design principles it is possible to obtain GTMS in which these stresses do not result in a weakening of the structure but, on the contrary, are used to obtain particularly stable devices. Please click on the GTMS product pages for more information.
Glass Powder
Glass can exhibit a broad variety of characteristics and features when ground and milled to different grain sizes. Technical glass powders, for example, are used in glass-to-metal sealing or in the passivation of discrete semi-conductor devices. Biocompatible or biologically active glass powders, on the other hand, are found in medical, dental or cosmetic applications. Please refer to our Special Glass Product Division for more information.
Gold Plating
A method of plating whereby uniform metal deposits are obtained from plating solutions in which gold ions are present as a complex. Please click on this page for more information.
Hermetic Sealing
This term refers to an air-tight seal designed to secure electronic components from any external factors that could impact its functioning and workable lifetime.
High-Temperature Co-fired Ceramics (HTCC)
"High-temperature co-fired ceramics (HTCC)" are primarily a multi-layered ceramic material used as inserts in glass-to-metal packages. Complete ceramic packages can be built. Two or more layers of ceramic tape with thicknesses ranging from 5 to 25 mm are co-fired at temperatures of more than 1000 degrees Celsius. The ceramic tape layers consist of aluminum oxide ceramic, tungsten and molymanganese and have metallized circuit patterns.
Humidity Sensors
Humidity sensors (or hygrometers) measure the vapor content of air. They contain a hygroscopic material (a material that retains water), which experiences property changes as a result of humidity.
Hybrid Package
A hybrid package, also known as a microelectronic package, a metal wall package, a flat pack or a glass-to-metal package, refers to the hermetically sealed packaging of electronic components within one container.
Insulation Resistance
Insulation resistance is the electrical resistance of an insulating material to a direct voltage. It is determined by measuring the leakage of current which flows through the insulation.
Large-scale Feedthrough
Used in applications such as power plants, a large-scale feedthrough allows electrical cables, for energy flow, control, measurements, and monitoring, to be fed through containment walls in the form of gas tight penetrations.
Laser Welding
"Laser welding" is a welding technique used to join multiple pieces of metal with the use of a laser. The beam provides a concentrated heat source, allowing for narrow, deep welds and high welding rates. The process is frequently used in high volume applications, such as in the automotive industry.
Low Temperature Co-fired Ceramics (LTCC)
LTCC allows passive components such as resistors, inductors and capacitors to be embedded into a multi-layer, integrated module by co-firing special ceramic tapes at temperatures below 900 degrees Celsius.
Matched Seals
A matched seal is designed to seal Fe-Ni-Co alloy (otherwise known as Kovar or KV) with glass. The thermal expansion coefficient of Kovar is compatible with that of glass over a wide range of temperatures. The matched seal type can be used to make a variety of terminals with comparatively few restrictions on the terminal shape. At the same time, it provides high air-tightness and electrical insulation.
Metal Wall Package
Also known as a hybrid/ microelectronic package, a glass-to-metal package or a flatpack, it refers to the hermetically sealed packaging of electronic components within one container that is provided with metal side walls.
Micro-Electro-Mechanical Systems (MEMs)
MEMs is the integration of mechanical elements, sensors, actuators, and electronics on a common silicon substrate through microfabrication technology.
Microfluidics
Microfluidics is the science of designing and manufacturing devices which can channel very small fluid flows, in the microliter or nanoliter range. Systems using microfluidics must be manufactured very precisely, and glass is a common material used in this area.
Modulus of Elasticity
The "modulus of elasticity" is the ratio of stress to the corresponding strain below the proportional limit of a material.
Molded Cap
A molded (TO) cap is a cap where an optical glass is fused at high temperatures onto the metal frame without using any other interface materials. Please click on the molded cap page for more information.
Monolithic Filter
A "monolithic filter" is a frequency selective device, constructed on a single piezoelectric crystal plate, and is used to separate telephone communications sent simultaneously over the transmission line.
Nickel Electroplating
When nickel salts are dissolved in water, nickel ions are formed. The nickel is deposited by applying an external current to the cathode. At the same time, the metallic nickel is dissolved at the anode.
Organic Light-emitting Diode (OLED)
An OLED consists of an emissive organic material, that when supplied with an electrical current, can produce a superior full-color flat panel display.
Oscillator Package
An "oscillator package" is an electronic circuit, packaged hermetically, that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency.
Passivation Glass Powders
Milled zinc borosilicate passivation glasses are used for hermetic passivation of high-voltage diodes, thyristors, and transistors. They provide high-junction temperatures and can be applied to wafers using thick film and electrophoresis methods. These products are formulated and produced to achieve low alkali and iron levels. Please clilck on this page for more information.
Piezoelectricity
"Piezoelectricity" is the phenomenon whereby an electric potential is generated by a certain material placed under mechanical pressure.
Poisson's Ratio
"Poisson's ratio" is the ratio of the relative contraction strain, or transverse strain (normal to the applied load), divided by the relative extension strain, or axial strain (in the direction of the applied load).
Reed Switch
A "reed switch" is an electrical switch operated by a magnetic field. It contains two magnetizable and electrically conductive metal reeds that have end portions separated by a small gap when the switch is open. The reeds are hermetically sealed in opposite ends of a tubular glass envelope. Please click on this page for more information.
Resistance Welding
This is a welding technique that uses the application of an electric current and a mechanical pressure to create coalescence between two pieces of metal.
SEFUSE®
NEC SCHOTT SEFUSE® products are compact and reliable thermal cutoffs designed to protect domestic electrical appliances and industrial electrical equipment from overheating. When the ambient temperature increases to an abnormal level, the electrical circuit opens and cutoff occurs. NEC SCHOTT SEFUSE® products are well recognized and meet all relevant international industrial safety standards. Please click on this page for more information.
SF Type
The NEC SCHOTT SEFUSE® SF Type is a thermal cutoff based on a one shot operation principle in order to prevent electrical appliances from catching fire due to overheating. It uses an organic thermo-sensitive material inside a metal case and is able to operate in electric circuits with large currents. Please refer to our SF type product page for more information.
Shelled TO Header
A shelled header is a metal shell that is shaped using the deep draw process.
SH Type
The NEC SCHOTT SEFUSE® SH type is integrated into the current circuit of an electrical appliance, with the purpose of interrupting the electrical flow when overheating leads to dangerous levels. Please refer to the SH type product page for more information.
Sintered Glass Preforms
Formed glass beads are produced using glass powder mixed with organic material for easy dry-pressing and sintering at temperatures that allow for the evaporation of the organic material and the simultaneous baking of a firm preform used in glass-to-metal sealing.
Sintering
This is a process by which glass powders, for easy dry-pressing, are mixed with organic material and are 'baked' at temperatures that allow for the evaporation of the organic material while simultaneously forming the glass powder into a firm preform.
SM Type
The NEC SCHOTT SEFUSE® SM Type is a thermal cutoff designed to protect home electrical appliances and industrial electrical equipment from catching fire. It contains a fusible alloy inside an insulated case that interrupts the electrical circuit by melting when the ambient temperature reaches an abnormal level. It also contains a resistor that allows for protection against current surges. Please click on the SM type product page for more information.
Soldered Cap
A soldered (TO) cap is a cap with a window or optical lens soldered and not molded to the top of a metal ring. This type of cap is suitable for precision applications with special optical components. Please click on the soldered cap page for more information.
Surface Resistivity
"Surface resistivity" is the resistance to leakage current along the surface of an insulating material.
Thermal Conductivity
"Thermal conductivity" refers to the rate of heat transfer by conduction. It is dependent on many properties of the material, notably its structure and temperature.
Thermal Cutoff
A "thermal cutoff" is an electrical safety device that interrupts the electrical current flow when heated beyond a specific temperature. Please click on this page for more information.
Thermal Expansion Coefficient
The thermal expansion coefficient relates the change in temperature to the change in a material's linear dimensions.
TO Cap
As part of a TO package, A TO cap fulfills two primary functions. First, it reliably and permanently protects the optical components of transmission as well as reception applications. Second, it ensures the transmission of the optical signals by acting as an optical interface. The optical properties of the windows or lenses installed into the cap must therefore fulfill extremely stringent requirements. Please click on this page for more information.
Transistor Outline (TO) Packages
A Transistor Outline (TO) is the name of an international industrial standard that governs a particular type of current-conducting electronic housing. A TO package always consists of two components: a header and a cap.
Transponder
An automatic device that transmits a predetermined message in response to a predefined received signal.
Viscosity
Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction.
Volume Resistivity
Volume resistivity is defined as the ratio of the DC voltage drop per unit thickness to the amount of current per unit area passing through the material. It also indicates how readily a material conducts electricity through the bulk of the material.
ZERODUR® Zero Expansion Glass-Ceramic
SCHOTT Zerodur® is a glass-ceramic material with an extremely low thermal expansion coefficient. Please click on this page for more information.