Interferometry | Spectrometry | V-block refractometer | High-precision spectral goniometer "URIS" | High-precision dilatometer | Magnetron sputtering devices | Thermal evaporation | Hot reactive electron beam evaporation | Ion-assisted evaporation | Reactive ion plating | CNC grinding machines | 3-D coordinate measurement devices | Lapping machines | Polishing machines | MRF polishing machines | Single grain diamond lathes | Etching equipment | Sandblasting machines | Ultra-sonic vibration lapping machines
SCHOTT works with an international network of research and competence centers along the entire value chain and has access to the latest state-of-the art technologies:
This measurement technique is used to measure the refractive index homogeneity to characterize highly homogeneous glasses. In this case, the wave front deformation of a laser beam is measured at twice the average by the tester. This measurement is normally performed on blocks and round plates.
A spectrometer measures values such as transmission, but also color code, color code index, etc. Spectrometry is normally used on optical glass and colored glass.
This measures the refractive index extremely accurately down to even ±20 · 10–6. Due to the high degree of automation, up to 10 samples of various sizes can be combined in a V-block stack and measured during a single measurement sequence.
The high-precision, automated spectral goniometer “URIS” (ultraviolet to infrared "URIS" Refractive Index Measurement System) is capable of measuring the refractive index of optical glasses with an accuracy of up to ±4 · 10–6 inside the spectral region of 185 nm to 2,325 nm.
The dilatometer developed by SCHOTT to deliver the highest possible precision measures the thermal expansion coefficients (CTE - Coefficient of Thermal Expansion) of ZERODUR® with reproducibility of up to 1.2 ppb/K in the temperature range of between 0 °C and 50 °C. Sample sizes of up to 100 mm in length and 6 mm in diameter can be measured.
Magnetron sputtering devices rank among the most powerful coating apparatuses that are used to vapor deposit particles on the basis of plasma to produce high-quality interference filters of up to 200 mm in diameter and 40 mm in thickness. Thanks to the extremely stable growth of the layers, the excellent control of the layer thicknesses, the ability to apply multiple layers, for instance extremely hard and scratch-resistant AR coatings on sapphire substrates, and the high total thickness of the layer, extremely small band bandpass filters, steep edge filters or so-called notch filters (triple notch, for instance) are possible. These types of filters are used in the area of fluorescence microscopy or Raman spectroscopy.
With thermal evaporation onto cold substrates, the coating material is vapor deposited by the target (the coating material is referred to as the target) at a high temperature and condenses on top of the cold substrate as a thin layer. This method makes it possible to use the maximum number of various target materials (that have different refractive indexes), especially with low refractive materials with excellent transmission in the UV region. For this reason, this method is used for UV filters or for filters that require coatings with special refractive indexes.
With hot reactive electron beam evaporation, the target is evaporated and deposits itself on an evaporation hot substrate when oxygen is added. This helps to achieve hard coatings that only exhibit minor temperature effects. The filters manufactured in this manner can normally be used at temperatures of up to about 350°C.
With ion-assisted evaporation, the targets evaporated by an electron beam are also bombarded by ions rich in energy as they grow up on the substrate. By adjusting the ion beam, the properties of the layers can be modified to accommodate the refractive index or packing density of the coating.
With reactive ion plating, the metal target material is evaporated using an electron beam, plasma, and bombardment with ions and vapor deposited onto the substrate by adding a reactive gas as an oxidic layer (a TiO2 layer, for example). This technique achieves extremely dense layers that are exceptionally durable and thermally stable.
Multi-axis CNC (Computerized Numerical Control) machines (up to 5 axes) are used to manufacture complex shapes of prototypes and perform mass manufacturing, but also to manufacture free-formed surfaces of up to 4.25 m in size (ZERODUR® mirror substrates, for example).
Checking of measurement and form tolerances is performed using highly accurate 3-D CNC coordinate measurement devices. A mobile 3-D laser tracking measurement device is also available for use on parts that exceed 1.5 m in size. The direct feedback that manufacturing receives makes it possible to further advance the production of delicate structures rather quickly.
Lapping represents a preliminary step to polishing. Further refinement with the help of lapping agents (abrasives with a geometrically undefined cutting edge) is performed to remove only a small amount of material, and this in turn allows for the precision of the geometry of the final surface to be achieved.
The single- and double-sided polishing machines at SCHOTT make it possible to manufacture plano and plano-plano-parallel components with diameters of up to 650 mm.
The MRF polishing (magnetorheological fine processing) machines at SCHOTT allow for the rotation symmetry of spherical and aspherical surfaces to be processed extremely accurately and enable superior surface quality thanks to the high flexibility of the polishing liquid. Polished aspheres can be manufactured from spheres using a cold processing process, for instance.
A geometrically-defined single grain diamond makes it possible to produce extremely precise surfaces. At SCHOTT, this machine is mainly used to process aspherical lenses made of infrared material with a maximum diameter of 250 mm.
SCHOTT has access to technologies for use in etching substrates made of glass and glass-ceramics. A specially-developed system makes it possible to etch mirror substrates made of the extremely low expansion material ZERODUR® (diameters of up to 4.25 m) to reduce tensions inside the material that are caused by processing and increase its resistance to breakage.
Thanks to a specially-developed sandblasting technique, specific structures can be created in wafers with the help of structuring masks that are specially designed to suit the respective final product.
By combining ultrasound excited tools and a solvent that contains abrasive components, machine-defined structures can be produced in wafers to meet specific customer requirements. SCHOTT is even capable of structuring large surfaces in a single working process.
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