Device for determining optical properties of an optically transparent substrate, coating system, and use of a measurement system

Abstract

A device (22) for determining optical properties of a substrate (14), which is provided with a substrate coating (12), has a vacuum chamber (26) and a measurement system (28) with a measurement device (30), wherein the measurement device (30) is arranged in the vacuum chamber (26). The measurement device (30) comprises a first measurement unit (34) which is associated with a first side (37) of the substrate (14), wherein the first measurement unit (34) comprises a first emission unit (39) for irradiating a measurement region (40) of the substrate (14) with directed electromagnetic radiation, and a collector unit (48) which is designed to collect electromagnetic radiation. The measurement system (28) has a source (44) for electromagnetic radiation which is connected to the first emission unit (39) via a supply switching element (42), and a detector (52) which is connected to the collector unit (48) via a detector switching element (50). The source (44) for electromagnetic radiation and the detector (52) are arranged outside the vacuum chamber (26) of the device (22).

Description

[0001] Device for determining the optical properties of an optically transparent substrate, coating system and use of a measuring system

[0002] The invention relates to a device for determining the optical properties of an optically transparent substrate, a coating system for producing an optical substrate, and the use of a measuring system in a device for determining the optical properties of an optically transparent substrate.

[0003] In the production of optically transparent substrates, for example for building glazing and solar modules, coatings are typically applied to the substrate to create a desired property profile, such as with regard to transmission properties or thermal insulation. In this context, it is of great importance to be able to reliably determine the quality and the actual optical behavior achieved by the coated substrate.

[0004] In this context, measurement systems are known in which the coated substrate is examined using a measuring unit designed to emit electromagnetic radiation towards the substrate. For this purpose, the measuring unit has an emission unit, which is typically oriented perpendicular to the surface of the substrate, so that it is irradiated with electromagnetic radiation that thus strikes the substrate perpendicularly. Using detector units associated with the emission unit, the transmission and reflection of the electromagnetic radiation can be measured, and conclusions can be drawn about the quality of the coated substrate.

[0005] Particular challenges arise in production facilities where the coated substrate is to be examined within a vacuum chamber, for example, following a coating step carried out under vacuum. This is because the components required for operating the measuring unit must either also be located within the vacuum chamber or the vacuum chamber must be equipped with gas-tight vacuum feedthroughs to externally located components. In particular, movable components such as aperture devices within the vacuum chamber increase the design requirements and can negatively impact the ability to maintain a uniform vacuum within the chamber.

[0006] The object of the invention is to provide a device with which the optical properties of an optically transparent substrate can be reliably and precisely determined in a vacuum.

[0007] In one aspect, the object of the invention is achieved by a device for determining the optical properties of an optically transparent substrate, which is provided on a first side with a substrate coating, wherein the device comprises a vacuum chamber and a measuring system with at least one measuring device, the at least one measuring device being arranged in the vacuum chamber. The at least one measuring device comprises a first measuring unit associated with the first side of the substrate, wherein the first measuring unit comprises a first emission unit for irradiating a measuring area of ​​the substrate associated with the measuring device with directed electromagnetic radiation, and a collector unit configured to collect electromagnetic radiation emitted by the first emission unit and reflected by the substrate in the measuring area.The measuring system further comprises a source of electromagnetic radiation connected to the first emission unit via a supply switching element, and a detector connected to the collector unit via a detector switching element. The source of electromagnetic radiation and the detector are arranged outside the vacuum chamber of the device.

[0008] The invention is based on the fundamental idea of ​​minimizing the number of components of the device or measuring system located within the vacuum chamber, while simultaneously enabling a flexible design of the measuring system for measurements within the vacuum chamber. This is achieved via the power supply switching element and the detector switching element, which connect the at least one measuring unit located within the vacuum chamber to the electromagnetic radiation source and the detector located outside the vacuum chamber. In this way, the number of components within the vacuum chamber and the number of necessary vacuum feedthroughs can be minimized, and it is simplified to maintain a relatively constant vacuum within the vacuum chamber.

[0009] Furthermore, by locating the source of electromagnetic radiation outside the vacuum chamber, a longer lifespan of the source is achieved, since it heats up less outside the vacuum due to the heat generated during operation than would be the case if it were operated in a vacuum, where heat dissipation is impaired due to the low pressure inside the vacuum chamber.

[0010] According to the invention, the first emission unit also emits directed electromagnetic radiation. In this context, the term "directed electromagnetic radiation" means that the electromagnetic radiation is emitted with collimated beam guidance in the direction of the substrate; that is, it is collimated radiation or collimated light. Such collimated radiation is free of scattered light components, apart from unavoidable scattered light components from the surroundings of the measuring area. In other words, directed electromagnetic radiation is not diffuse light, so the first emission unit is not a diffuse emission unit. In this way, the measurement results of the measuring system are particularly insensitive to ambient light and scattered light, especially compared to measurements carried out with homogenized light sources.This makes it possible to minimize any sources of error in the measurement data obtained by means of the detector and thus to optimize the quality in the determination of the optical properties of the substrate.

[0011] The supply switching element is designed to connect or disconnect the source of electromagnetic radiation and the first emission unit in order to switch the emission unit on or off.

[0012] The detector switching element is designed to connect or disconnect the collector unit and the detector in order to direct or prevent electromagnetic radiation collected by the collector unit from reaching the detector.

[0013] The at least one measuring device can further comprise a second measuring unit assigned to a second side of the substrate, opposite the first side of the substrate, wherein the second measuring unit comprises a second emission unit for irradiating the measuring area with directed electromagnetic radiation, and wherein the collector unit is configured to collect electromagnetic radiation emitted by the second emission unit and transmitted through the substrate in the measuring area. The second measuring unit thus makes it possible to determine not only the reflection properties of the coated substrate in the measuring area, but also its transmission properties.By using the same collector unit for collecting transmitted electromagnetic radiation as is used for collecting reflected electromagnetic radiation, the number of components of the measurement system that need to be provided in the vacuum chamber can be minimized.

[0014] The second emission unit is also designed to emit directed electromagnetic radiation towards the substrate, analogous to how the first emission unit was described previously.

[0015] It is understood that the substrate coating on the first side of the substrate may only partially cover that side. Furthermore, the second side of the substrate may also be coated, and the coatings on the first and second sides may be the same or different. The substrate coating may also comprise one or more layers. The crucial factor is that the coatings applied to the optically transparent substrate result in a still optically transparent coated substrate.

[0016] To further reduce the complexity of the measurement system, the second emission unit is connected to the electromagnetic radiation source, specifically via the power supply switching element. In other words, the same power supply switching element that supplies the first emission unit also supplies the second emission unit with electromagnetic radiation. This eliminates the need for a separate power supply switching element for the second emission unit and / or an additional electromagnetic radiation source for the second emission unit.

[0017] The power supply switching element is specifically designed to simultaneously activate the first emission unit and deactivate the second emission unit, as well as to simultaneously deactivate the first emission unit and activate it. In other words, the power supply switching element is designed to activate only one of the emission units of the measuring device as needed, while the other emission unit is deactivated.

[0018] If both the first and second emission units are supplied by the same source of electromagnetic radiation, particularly via a common power supply element, the measured values ​​obtained by reflection and transmission in the first collector unit can be calibrated by comparing the measured values. In particular, temporal changes in the intensity and / or spectrum of electromagnetic radiation generated by the source can be detected and taken into account in the further evaluation of the measurement data.

[0019] The second measuring unit can include a second collector unit configured to collect electromagnetic radiation emitted by the first emission unit and transmitted through the substrate within the measuring range. In this way, the transmission properties of the coated substrate can also be determined using electromagnetic radiation that initially strikes the first side of the substrate.

[0020] The second collector unit is connected to the detector, in particular via the detector switching element. In other words, the same detector is used to evaluate the electromagnetic radiation collected by the second collector unit as is used to evaluate the electromagnetic radiation collected by the first collector unit. Therefore, a separate detector switching element for the second collector unit and / or an additional detector for the second collector unit are not required.

[0021] The first emission unit and / or the second emission unit can be oriented towards the substrate such that the electromagnetic radiation emitted by the first emission unit strikes the substrate at a first emission angle, and the electromagnetic radiation emitted by the second emission unit strikes it at a second emission angle, relative to the normal of the side of the substrate assigned to the respective emission unit. In this configuration, the first and second emission angles are not equal to 0° and are particularly in the range of 3 to 10°.

[0022] At least one measuring device can be installed within the vacuum chamber in a support structure of the measuring system. This simplifies the assembly, disassembly, and maintenance of the measuring system, as the at least one measuring device can be handled via the support structure and, for example, inserted into and / or removed from the vacuum chamber. Furthermore, the support structure protects the measuring device from mechanical damage and / or contamination, for example, caused by sputtering.

[0023] The carrier device is particularly advantageous when the measuring system has several measuring devices, each of which is inserted into the carrier device, so that all measuring devices can be handled together via the carrier device.

[0024] The measuring system can comprise several measuring devices, in particular two to ten measuring devices, for example, two to five measuring devices. With a multitude of measuring devices, the same measuring area of ​​the substrate can be measured multiple times while the substrate is moved along a processing direction. This allows for multiple determinations of the optical properties of the substrate at the same location, i.e., in the same measuring area, without any reduction in the substrate's speed. Alternatively or additionally, it is possible to measure different measuring areas of the substrate simultaneously, with each measuring device assigned a specific measuring area to enable spatially resolved determination of the substrate's optical properties.

[0025] In particular, the use of multiple measuring devices makes it possible to eliminate the need for a measuring device that moves within the vacuum chamber and still perform multiple measurements and / or spatially distributed measurements. This further reduces the number of moving components within the vacuum chamber.

[0026] The multiple measuring devices can be identical to each other or at least partially different from each other, for example, configured for operation with electromagnetic radiation of different spectra. Preferably, however, the measuring devices are identical to each other.

[0027] To minimize the number of components in the measuring system, the first emission units of several measuring devices can be connected to the electromagnetic radiation source via the same supply switching element, and / or the collector units of several measuring devices can be connected to the detector via the same detector switching element; preferably, all measuring devices. This minimizes the number of electromagnetic radiation sources and / or detectors required for operating the measuring devices, preferably requiring only a single electromagnetic radiation source and / or a single detector.

[0028] If one or more measuring devices have second emission units, these can also be connected to the same supply switching element, in particular to the same supply switching element as the first emission units. If one or more measuring devices have second collector units, these can also be connected to the same detector switching element, in particular to the same detector switching element as the first collector units.

[0029] The power supply switching element and / or the detector switching element can be located inside the vacuum chamber. Therefore, only a vacuum feedthrough is required for the connecting line between the electromagnetic radiation source and the power supply switching element, or between the detector switching element and the detector, which provides a gas-tight connection between the vacuum chamber and the environment, even if the same power supply switching element and / or the same detector switching element is connected to a multitude of emission units or collector units.

[0030] In one variant, the vacuum chamber has only one source vacuum feedthrough for the connection from the source to the supply switching element and / or only one detector vacuum feedthrough for the connection from the detector switching element to the detector.

[0031] In another variant, the vacuum chamber has a single vacuum feedthrough for the connection from the source to the supply switching element as well as for the connection from the detector switching element to the detector.

[0032] The power supply switching element and / or the detector switching element is in particular a fiber switch.

[0033] Fiber switches, also known as fiber optic switches, are characterized by a particularly short switching time combined with a high number of cycles. Fiber switches have one or more piezoelectric actuators. The respective piezoelectric actuator connects or disconnects the fiber ends of the fiber switch. The fiber ends to be connected or disconnected are each assigned to a terminal or output of the fiber switch.

[0034] The fiber switch can have one or more connection points to which the electromagnetic radiation source or the respective collector unit is connected. In particular, the measuring system can have multiple electromagnetic radiation sources, each of which is connected to a different connection point, or multiple collector units, each of which is connected to a different connection point. Preferably, however, only a single electromagnetic radiation source is used. Furthermore, the fiber switch can have one or more outputs connected to one of the first emission units or one of the second emission units to which the fiber switch is assigned.

[0035] Naturally, the fiber switch can also have a different number of connection points and outputs, for example a single connection point and several outputs.

[0036] In particular, the fiber switch has fewer connection points than outputs, allowing the number of openings in the vacuum chamber to be kept to a minimum, while simultaneously supplying multiple emission units with electromagnetic radiation from the same fiber switch or allowing multiple collector units to transmit received electromagnetic radiation to the same fiber switch. The same principle applies analogously when the fiber switch is used as a detector switching element, except that in this case, the fiber switch has fewer outputs than connection points.

[0037] A fiber switch is also characterized by high attenuation between the connection channels, which result from connecting the respective fiber ends, so that the connection made is unaffected or at least as little affected as possible by the other available fibers of the fiber switch.

[0038] It is understood that the fiber switch must be at least partially transparent to that portion of the electromagnetic radiation generated by the source(s) of electromagnetic radiation and intended to be emitted by the respective emission unit, or collected by the collector unit(s) and directed to the detector. For example, the fiber switch has an operating wavelength range of 250 to 2500 nm, particularly from 275 to 2100 nm.

[0039] In one variant, the operating wavelength range is limited to visible light and the near-infrared of the electromagnetic spectrum, specifically to an operating wavelength range of 380 to 1,000 nm. In another variant, the operating wavelength range is limited to visible light of the electromagnetic spectrum, specifically to an operating wavelength range of 380 to 780 nm.

[0040] The switching frequency of the fiber switch is typically in the range of 0.005 to 30 Hz, for example, from 0.01 to 20 Hz. This allows the fiber switch to perform another switching operation after only a short time delay.

[0041] The power supply switching element and / or the detector switching element can also comprise several fiber switches as described above, cascaded in series. In such a circuit, at least one output of the fiber switch located upstream in the cascade is connected to an input of the fiber switch located downstream in the cascade. This allows all cascaded fiber switches to be supplied by a single source of electromagnetic radiation or to transmit electromagnetic radiation to the detector via a common output. This reduces the space required for the power supply switching element and / or the detector switching element, as well as the number of vacuum feedthroughs.

[0042] Preferably, the supply switching element and / or the detector switching element have a switching time of 30 ms or less, in particular 10 ms or less.

[0043] The power supply switching element can also be configured to function as a shutter for the measuring system, for example, to perform a dark calibration of the measuring system. This eliminates the need for alternative shutter devices such as a CCD shutter, an electronic iris, or a mechanical aperture.

[0044] The collector unit can include an integrating sphere, for example, an integrating sphere. Such integrating spheres are readily available at low cost and suitable for operation within a vacuum chamber without excessive maintenance.

[0045] The collector unit can include a collimator positioned upstream of the integrating sphere in the electromagnetic radiation path, which focuses the rays incident on the integrating sphere onto a focal point. The detector can be a spectrometer, in particular a NIR, VIS, and / or near-UV spectrometer, preferably a VIS spectrometer. The optical properties of the substrate in the visible region of the electromagnetic spectrum are of particular importance in the production of coated, optically transparent substrates. However, adjacent regions of the electromagnetic spectrum can also be evaluated by the spectrometer to better assess the effects of the coating, which are particularly pronounced in these wavelength ranges.

[0046] The near-UV range covers in particular a wavelength range of 350 to 380 nm, the VIS range a wavelength range of 380 to 780 nm and the NIR range a wavelength range of 780 to 2100 nm.

[0047] Additionally, the measuring system can include a unit for measuring the substrate's surface resistance, specifically for performing an eddy current measurement within the substrate's measuring area. The surface resistance allows for the investigation of the substrate's properties using a complementary method for determining its optical properties, enabling the determination of further parameters of the coated substrate and / or the verification of information obtained by the detector. For example, eddy current measurements can be used to draw conclusions about the Krista II structure of the substrate and / or the substrate coating.

[0048] In a second aspect, the problem is solved according to the invention by a device for determining the optical properties of an optically transparent substrate, which is provided on a first side with a substrate coating, wherein the device comprises a vacuum chamber and a measuring system with at least one measuring device, the at least one measuring device being arranged in the vacuum chamber. The at least one measuring device comprises a second measuring unit, which is assigned to a second side of the substrate opposite the first side of the substrate, wherein the second measuring unit comprises a second emission unit for irradiating a measuring area of ​​the substrate assigned to the measuring device with directed electromagnetic radiation.The measuring device further comprises a first measuring unit associated with a first side of the substrate, the first measuring unit comprising a collector unit configured to collect electromagnetic radiation emitted by the first emission unit and transmitted through the substrate in the measuring area. The measuring system further comprises an electromagnetic radiation source connected to the second emission unit via a supply switching element. The measuring system further comprises a detector connected to the collector unit via a detector switching element. The electromagnetic radiation source and the detector are arranged outside the vacuum chamber of the device.

[0049] The properties and features of the device according to the first aspect of the invention apply analogously to the device according to the second aspect of the invention, and vice versa. In particular, the components of the device according to the first aspect correspond to the components of the device according to the second aspect. Furthermore, the additional components described for the device according to the first aspect of the invention can also be present analogously in the device according to the second aspect of the invention.

[0050] For example, in the device according to the second aspect of the invention, the first measuring unit can further comprise the first emission unit, which is configured to emit directed electromagnetic radiation onto the measuring area associated with the measuring device, wherein the collector unit is configured to collect electromagnetic radiation emitted by the first emission unit and reflected by the substrate in the measuring area. In this case, it is also possible in the device according to the second aspect of the invention to perform both transmission and reflection measurements.

[0051] According to a third aspect, the object of the invention is further achieved by a coating system for producing an optically transparent substrate with a substrate coating applied to a first side of the substrate, comprising a device for determining the optical properties of the optically transparent substrate as described above. The properties and features of the devices according to the invention apply accordingly to the coating system according to the invention and vice versa, and reference is made to the above explanations.

[0052] The device for determining optical properties can be directly connected to a coating module of the coating system or be spatially separated from it. It is particularly advantageous if the vacuum chamber of the device is directly connected to the coating module, so that the coating module and the vacuum chamber form a common vacuum volume. It is also possible for the device for determining optical properties to be integrated into the coating module.

[0053] In one variant, the device for determining optical properties is integrated into the coating system in such a way that the optical properties of the optically transparent substrate are measured during the coating process itself. For example, the measuring area is selected in a portion of the substrate that has already been coated, while upstream along a processing direction of the coating system, another portion of the substrate is being coated. In this variant, it is possible to adjust the coating process based on the determined optical properties.

[0054] Furthermore, the object of the invention according to a fourth aspect is solved by the use of a measuring system comprising at least one measuring device with a first measuring unit comprising a first emission unit for irradiating a measuring area of ​​a substrate associated with the measuring device with directed electromagnetic radiation and a collector unit configured to collect electromagnetic radiation emitted by the first emission unit and reflected by the substrate in the measuring area, and / or comprising at least one measuring device with a first measuring unit and a second measuring unit, wherein the second measuring unit comprises a second emission unit for irradiating a measuring area of ​​a substrate associated with the measuring device with directed electromagnetic radiation, and wherein the first measuring unit comprises a collector unit configured to collect electromagnetic radiation.The electromagnetic radiation emitted by the second emission unit and transmitted through the substrate in the measuring area is used to determine the optical properties of the substrate. The measuring system also has a source of electromagnetic radiation connected to the first emission unit and / or the second emission unit via a supply switching element. The measuring system further includes a detector connected to the collector unit and / or the second collector unit via a detector switching element. The at least one measuring device is arranged in a vacuum chamber of a device as described above, and the source of electromagnetic radiation and the detector are arranged outside the vacuum chamber of the device.

[0055] The properties and features of the devices according to the invention apply accordingly to the use of the measuring system according to the invention and vice versa, and reference is made to the above explanations. In particular, the measuring system can be configured as described above for the devices according to the invention.

[0056] Further features and characteristics of the invention will become apparent from the following description of exemplary embodiments, which are not to be understood in a limiting sense, as well as from the drawings to which reference is made. These show:

[0057] - Fig. 1 a coating system according to the invention,

[0058] - Fig. 2 selected parts of a first embodiment of a device according to the invention for determining optical properties, as used in the coating system according to Fig. 1,

[0059] - Fig. 3 shows a schematic representation of selected parts of a collector unit of the device from Fig. 2,

[0060] - Fig. 4 selected parts of a second embodiment of a device according to the invention for determining optical properties, and

[0061] - Fig. 5 shows selected parts of a third embodiment of a device according to the invention for determining optical properties. Fig. 1 schematically shows a coating system 10 for applying a substrate coating 12 to an optically transparent substrate 14 (see Fig. 2).

[0062] Substrate 14, for example, is made of glass or plastic and is essentially flat. For instance, substrate 14 might be a plate with a rectangular cross-section and external dimensions of up to 4 x 9 meters. However, the type and shape of substrate 14 are not fundamentally restricted, as long as it is optically transparent and can be handled by the coating system 10.

[0063] In the following, the substrate 14 provided with the substrate coating 12 will also be referred to as "coated substrate 14".

[0064] The coating system 10 has a loading module 16, a coating module 18, a module 20 with a device 22 for determining optical properties of the coated substrate 14 and an unloading module 24, which are arranged successively along a processing direction B.

[0065] The loading module 16 serves to load the substrate 14 onto a roller arrangement 25 of the coating system 10, with which the substrate 14 can be moved along the processing direction B, for example at a speed of up to 5 m / min.

[0066] In coating module 18, the substrate coating 12 is applied to the substrate 14. The type of substrate coating 12 is not further restricted, as long as the coated substrate 14 is also optically transparent. For example, the substrate coating 12 could be an anti-reflective coating, a thermal coating, and / or a protective coating.

[0067] The coating module 18 features, in particular, a coating vacuum chamber in which a predefined negative pressure prevails, for example, a negative pressure suitable for applying the substrate coating 12 to the substrate 14 via a gas-phase process. In module 20, the optical properties of the coated substrate 14 are checked, as will be described in more detail below.

[0068] The coated substrate 14 can finally be removed in the discharge module 24, for example by means of a (not shown) removal mechanism.

[0069] The number and type of modules of the coating system 10 shown in Fig. 1 are merely exemplary, so naturally further and / or different modules may also be present in the coating system 10. For example, an additional washing module may be provided to remove any residues of the coating process in the coating module 18.

[0070] The coating system 10 has the device 22 according to the invention for determining optical properties of the optically transparent substrate 14. The device 22 comprises a vacuum chamber 26 and a measuring system 28.

[0071] During operation of the coating system 10, a predefined negative pressure prevails in the vacuum chamber 26, in particular the same negative pressure as in the coating vacuum chamber of the coating module 18. It is also possible that the coating vacuum chamber and the vacuum chamber 26 form a common vacuum volume in which the substrate 14 is moved.

[0072] The measuring system 28 has several measuring devices 30 arranged within the vacuum chamber 26. The measuring devices 30 are inserted into corresponding mounting positions on a carrier device 32. In this way, the several measuring devices 30 can be handled together using the carrier device 32, for example, inserted into the vacuum chamber 26 during the assembly of the coating system 10 and / or removed from the vacuum chamber 26 during disassembly or maintenance of the coating system 10.

[0073] In the illustrated embodiment, the measuring system 28 has two measuring devices 30. However, the measuring system 28 can also have only a single measuring device 30 or more than two measuring devices 30. For example, the measuring system 28 has two to ten measuring devices 30, in particular two to five measuring devices 30.

[0074] Each of the measuring devices 30 has a first measuring unit 34 and a second measuring unit 36, wherein the first measuring unit 34 is assigned to a first side 37 of the coated substrate 14 and the second measuring unit 36 ​​to a second side 38 of the coated substrate 14 (see Fig. 2). The first side 37 and the second side 38 are opposite each other, with the substrate coating 12 applied to the first side 37.

[0075] The measuring devices 30 can be identical or different from each other. If the structure and function of one of the measuring devices 30 are described below, the corresponding descriptions also apply to the other measuring devices 30, unless explicitly stated otherwise.

[0076] Fig. 2 shows in more detail selected components of the device 22 and their arrangement relative to the coated substrate 14.

[0077] As can be seen in Fig. 2, in the embodiment shown, the substrate coating 12 completely covers the first side 37 of the substrate 14, while there is no substrate coating on the second side 38 of the substrate 14.

[0078] Naturally, the substrate 14 can also be coated differently from the embodiment shown in Fig. 2. For example, the substrate coating 12 can be applied only to partial areas of the first side 37 of the substrate 14. Furthermore, the substrate coating 12 can also comprise several partial layers. Additionally, a substrate coating 12 can be present on both the first side 37 and the second side 38 of the substrate 14.

[0079] The first measuring unit 34 has a first emission unit 39, which is configured to emit directed electromagnetic radiation onto a measuring area 40 of the substrate 14 (represented by a dashed arrow), i.e., collimated radiation free of scattered light components. The measuring area 40 has a length of 30 mm or less, where the length describes the extent of the measuring area 40 along the direction in which the measuring area 40 is greatest. In the variant shown in Fig. 2, this is the extent parallel to the processing direction B.

[0080] The first emission unit 39 is connected to a source 44 for electromagnetic radiation via a supply switching element 42.

[0081] The respective connection is made via a fiber that is designed to transmit electromagnetic radiation of the desired wavelengths, for example via a suitably designed optical fiber.

[0082] The supply switching element 42 is arranged inside the vacuum chamber 26 and the source 44 is arranged outside the vacuum chamber 26, the connection between the supply switching element 42 and the source 44 being made via a source vacuum feedthrough 46, which otherwise seals the vacuum chamber 26 gas-tight against the environment of the coating system 10.

[0083] The power supply switching element 42 is a fiber switch that has a connection point for the connection to the source 44 and several outputs, wherein each of the first emission units 39 of the measuring devices 30 is assigned to one of the outputs of the power supply switching element 42. Accordingly, it can be determined via the power supply switching element 42 whether and which of the first emission units 39 are active or inactive at a given time.

[0084] To enable particularly fast switching, the supply switching element 42 has a switching time of 30 ms or less.

[0085] Source 44, for example, is an LED and / or a halogen lamp and emits, in particular, electromagnetic radiation with a spectrum in the VIS range and optionally in the near-UV, VIS and near-IR range of the electromagnetic spectrum.

[0086] It is understood that the supply switching element 42 must be at least partially transparent to that portion of the electromagnetic radiation generated by the source 44 and intended to be emitted by the respective first emission unit 39. For example, the supply switching element 42 has an operating wavelength range of 250 to 2500 nm, in particular from 275 to 2100 nm.

[0087] Because the supply switching element 42 can determine whether and which of the first emission units 39 are active, the supply switching element 42 can function as an aperture, so that no additional component needs to be provided to separate the source 44 from the respective first emission unit 39 if necessary.

[0088] There can also be more than one source 44, in particular several sources 44 that generate electromagnetic radiation with different spectra. In this case, the number of connection points of the supply switching element 42 is adapted to the number of sources 44.

[0089] The first measuring unit 34 further comprises a collector unit 48 which is designed to collect electromagnetic radiation emitted by the first emission unit 39 and reflected by the substrate 14 in the measuring area 40.

[0090] The collector unit 48 is connected to a detector 52 via a detector switching element 50, so that the electromagnetic radiation collected by the collector unit 48 can be directed to the detector 52 and evaluated in the detector 52.

[0091] The detector switching element 50 is arranged inside the vacuum chamber 26 and the detector 52 is arranged outside the vacuum chamber 26, the connection between detector switching element 50 and detector 52 being made via a detector vacuum feedthrough 54, which otherwise seals the vacuum chamber 26 gas-tight against the environment of the coating system 10.

[0092] In the illustrated embodiment, separate vacuum feedthroughs are used for the connection between source 44 and supply switching element 42, and between detector switching element 50 and detector 52. However, it is also possible that only a single vacuum feedthrough is present, through which the connection between source 44 and supply switching element 42 as well as between detector switching element 50 and detector 52 is established.

[0093] The detector switching element 50, analogous to the supply switching element 42, is also a fiber switch, but it has several connection points for the connection to the collector units 48 and one output for the connection to the detector 52, with each of the collector units 48 being assigned to one of the connection points of the supply switching element 42. Accordingly, it can be determined via the supply switching element 42 from which of the collector units 48 the detector 52 receives electromagnetic radiation at a given time.

[0094] More than one detector 52 may be present, in particular detectors for evaluating electromagnetic radiation of different wavelength ranges. For example, one detector 52 may be configured for evaluating electromagnetic radiation in the visible range and another detector 52 for evaluating electromagnetic radiation in the ultraviolet and / or near-infrared range. In this case, the number of outputs of the detector switching element 50 is adapted to the number of detectors 52. Preferably, however, only a single detector 52 is used, which covers the spectrum required for the respective application.

[0095] Fig. 3 shows an exemplary embodiment of the collector unit 48, in which the collector unit comprises an integrating sphere 55 and a collimator 56, wherein the collimator 56 is placed upstream in the beam path of the electromagnetic radiation.

[0096] When electromagnetic radiation (indicated by arrows) hits the collimator 56, the incident rays are focused onto a focal point 58 of the integration sphere 55.

[0097] An inlet opening 60 of the integration sphere 55 is arranged at the focal point 58. The electromagnetic radiation entering the integration sphere 55 via the inlet opening 60 can exit the integration sphere 55 via an outlet opening 64 and be directed to the detector switching element 50, which can then forward the electromagnetic radiation to the detector 52. The second measuring unit 36 ​​of the measuring device 30 has a second emission unit 66, which is configured to irradiate the same measuring area 40 with electromagnetic radiation as the first emission unit 39 of the first measuring unit 34, but from the second side 38 of the coated substrate 14.

[0098] For this purpose, the second emission unit 66 is also connected to the supply switching element 42, so that the second emission unit 66 can be supplied with electromagnetic radiation from the same source 44 as the first emission unit 39. Accordingly, the supply switching element 42 has a number of outputs sufficient to connect both the first emission units 39 and the second emission units 66 to the supply switching element 42.

[0099] Which of the first emission units 39 and the second emission units 66 are active or inactive at a given time can thus be controlled via the shared supply switching element 42.

[0100] The collector unit 48 is designed to collect electromagnetic radiation emitted by the second emission unit 66 and transmitted through the coated substrate 14. Thus, the transmission properties of the coated substrate 14 can be determined via the second emission unit, the collector unit 48, and the detector 52.

[0101] Because the first emission unit 39 and the second emission unit 66 are supplied by the same source 44 for electromagnetic radiation, the second emission unit 39 can be used for a reference or calibration measurement in order to detect any temporal changes in the intensity and / or in the spectrum generated by the source 44 and to take these into account when evaluating the measurement data obtained.

[0102] The first emission unit 39 and the second emission unit 66 are aligned relative to the coated substrate 14 such that the electromagnetic radiation emitted by the first emission unit 39 and the second emission unit 36 ​​strikes the substrate 14 at a first emission angle Qi and a second emission angle 02, respectively, relative to the normal 68 of the first side 37 and the second side 38. The first emission angle Qi and the second emission angle 02 are not equal to 0° and are in particular in the range of 3 to 10°, for example, 8°. This results in a space-optimized relative arrangement of the first emission unit 39, the second emission unit 66, and the collector unit 48.

[0103] The measuring system 28 further comprises a unit 70 for performing a measurement of the surface resistance of the coated substrate 14, namely a unit for performing an eddy current measurement. The unit 70 comprises two measuring probes 72 and 74, wherein the measuring probe 72 is assigned to the first side 37 of the coated substrate 14 and the measuring probe 74 to the second side 38 of the coated substrate 14.

[0104] The unit 70 enables the determination of properties of the coated substrate 14 based on the induction of currents in the coated substrate 14 and thus offers the possibility of determining the properties of the coated substrate 14 via a method that is complementary to optical measurement methods.

[0105] In this process, unit 70 examines the same measuring area 40 that is also to be irradiated by emission units 39 and 66, for example after the substrate 14 has been moved along the processing direction B up to the height of measuring probes 72 and 74.

[0106] The device 22 or the measuring system 28 according to the invention is characterized in particular by the fact that only a small number of openings need to be provided in the vacuum chamber 26, which makes it easier to maintain the desired vacuum within the vacuum chamber 26.

[0107] Furthermore, as few mechanically moving components as possible are located within the vacuum chamber 26, especially since the control of the emission units 39 and 66 is carried out via the supply switching element 42 and detector switching element 50, each designed as a fiber switch.

[0108] It is also possible, in principle, for the supply switching element 42 and / or the detector switching element 50 to be arranged outside the vacuum chamber 26. In this case, however, vacuum feedthroughs must be provided for the required number of connecting lines to the first emission units 39, the second emission units 66 and the collector units 48.

[0109] The operation of the source 44 and the detector 52 is simplified because they are not located inside the vacuum chamber 26. In particular, the source 44 can be operated at a power level that, due to the poorer thermal conductivity within the vacuum chamber 26, could lead to overheating of the source 44.

[0110] Fig. 4 shows selected parts of a second embodiment of the device 22 according to the invention, analogous to the illustration in Fig. 2.

[0111] The second embodiment is essentially the same as the one described above, so only the differences will be discussed below. Identical reference numerals denote identical or functionally equivalent components, and reference is made to the explanations above.

[0112] In the second embodiment, the second measuring unit 36 ​​additionally has a second collector unit 76, which is configured to collect electromagnetic radiation emitted by the first emission unit 39 and transmitted through the substrate 14 in the measuring area 40.

[0113] In this way, the transmission properties of the substrate 14 can also be measured starting from the first side 37. This can be particularly advantageous if the substrate coatings 12 on the first side 37 and the second side 38 differ from each other, or if only one side of the substrate 14 is coated.

[0114] The second collector units 76 are also connected to the detector 52 via corresponding connection points of the detector switching element 50. Thus, the same detector switching element 50 is used for transmitting electromagnetic radiation collected by the second collector unit 76 as is used to transmit electromagnetic radiation collected by the first collector unit 48 to the detector 52. Otherwise, the second collector units 76 are designed analogously to the previously described collector units 48.

[0115] Fig. 5 shows selected parts of a third embodiment of the device 22 according to the invention, analogous to the representation in Figs. 2 and 4.

[0116] The third embodiment essentially corresponds to the embodiments described above, so only the differences will be discussed below. Identical reference numerals denote identical or functionally equivalent components, and reference is made to the explanations above.

[0117] In the third embodiment, the second measuring units 36 of the measuring devices 30 each have the second emission unit 66, which is configured to irradiate the measuring area 40 assigned to the respective measuring device 30 with directed electromagnetic radiation.

[0118] The first measuring units 48 of the measuring devices 30 each have the collector unit 48, which is designed to collect the electromagnetic radiation emitted by the respective second emission unit 66 and transmitted through the substrate 14 in the measuring area 40.

[0119] In other words, the measuring devices 30 in the third embodiment are designed exclusively for measuring the transmission properties of the coated substrate 14. In this way, the complexity and cost of the device 22 can be reduced if only the transmission properties of the coated substrates 12 produced in the coating system are to be determined.

[0120] In this variant, it is particularly advantageous that the collector units 48 used for transmission measurement are arranged above the coated substrate 14, since any contaminants that could be introduced into the vacuum chamber 26 through the coated substrate 14 cannot accumulate on the collector units 48 due to gravity. In this way, the measurement accuracy of the measuring device 30 is further increased, even during extended operation. It is understood, however, that starting from the embodiment shown in Fig. 5, other components described in connection with the previous embodiments may also be present, for example, the first emission unit 39 and / or the second collector unit 76.

[0121] Reference symbol list

[0122] 10 coating system

[0123] 12 Substrate coating

[0124] 14 Substrat

[0125] 16 Loading module

[0126] 18 coating module

[0127] 20 Module

[0128] 22 Device for determining optical properties

[0129] 24 discharge module

[0130] 25 Roll arrangement

[0131] 26 Vacuum chamber

[0132] 28 Measuring system

[0133] 30 measuring devices

[0134] 32 Carrier device

[0135] 34 first measuring unit

[0136] 36 second measuring unit

[0137] 37 first page

[0138] 38 second page

[0139] 39 first emission unit

[0140] 40 measuring range

[0141] 42 Supply switching element 44 Source

[0142] 46 Source vacuum feed

[0143] 48 collector units

[0144] 50 Detector switching element

[0145] 52 Detector

[0146] 54 Detector vacuum feedthrough

[0147] 55 Integration sphere

[0148] 56 Collimator

[0149] 58 Focus

[0150] 60 Entrance opening

[0151] 64 Exit opening

[0152] 66 second emission unit

[0153] 68 Normal

[0154] 70 units for performing a measurement of surface resistance

[0155] 72 Measuring probe

[0156] 74 Measuring probe

[0157] 76 second collector unit

Claims

Patent claims 1. Device (22) for determining the optical properties of an optically transparent substrate (14) which is provided on a first side (37) with a substrate coating (12), wherein the device (22) comprises a vacuum chamber (26) and a measuring system (28) with at least one measuring device (30), wherein the at least one measuring device (30) is arranged in the vacuum chamber (26), wherein the at least one measuring device (30) comprises a first measuring unit (34) which is associated with the first side (37) of the substrate (14), wherein the first measuring unit (34) comprises a first emission unit (39) for irradiating a measuring area (40) of the substrate (14) associated with the measuring device (30) with directed electromagnetic radiation, and a collector unit (48) which is configured to collect electromagnetic radiation which is emitted by the first emission unit (39) and reflected by the substrate (14) in the measuring area (40).wherein the measuring system (28) further comprises a source (44) for electromagnetic radiation which is connected to the first emission unit (39) via a supply switching element (42), wherein the measuring system (28) further comprises a detector (52) which is connected to the collector unit (48) via a detector switching element (50), and wherein the source (44) for electromagnetic radiation and the detector (52) are arranged outside the vacuum chamber (26) of the device (22).

2. Device (22) according to claim 1, wherein the at least one measuring device (30) further comprises a second measuring unit (36) which is associated with a second side (39) of the substrate (14) which is opposite to the first side (37) of the substrate (14), wherein the second measuring unit (36) comprises a second emission unit (66) for irradiating the measuring area (40) with directed electromagnetic radiation, and wherein the collector unit (48) is configured to emit electromagnetic radiation collect the emitted by the second emission unit (66) and transmitted through the substrate (14) in the measuring area (40).

3. Device (22) according to claim 2, wherein the second emission unit (66) is connected to the source (44) for electromagnetic radiation via the supply switching element (42).

4. Device (22) according to claim 1 or 2, wherein the second measuring unit (36) comprises a second collector unit (76) which is configured to collect electromagnetic radiation emitted by the first emission unit (39) and transmitted through the substrate (14) in the measuring area (40).

5. Device (22) according to one of the preceding claims, wherein the at least one measuring device (30) is inserted within the vacuum chamber (26) in a support device (32) of the measuring system (28).

6. Device (22) according to one of the preceding claims, wherein the measuring system (28) comprises several measuring devices (30).

7. Device (22) according to claim 6, wherein the first emission units (39) of several of the measuring devices (30) are connected to the source (44) for electromagnetic radiation via the same supply switching element (42) and / or the collector units (76) of several of the measuring devices (30) are connected to the detector (52) via the same detector switching element (50).

8. Device (22) according to one of the preceding claims, wherein the supply switching element (42) and / or the detector switching element (50) are arranged inside the vacuum chamber (26).

9. Device (22) according to claim 8, wherein the vacuum chamber (26) has only one source vacuum feedthrough (46) for the connection from the source (44) to the supply switching element (42) and / or only one detector vacuum feedthrough (50) for the connection from the detector switching element (50) to the detector (52).

10. Device (22) according to claim 8, wherein the vacuum chamber (26) has a single vacuum feedthrough for the connection from the source (44) to the has a supply switching element (42) and a connection from the detector switching element (50) to the detector (52).

11. Device (22) according to one of the preceding claims, wherein the supply switching element (42) and / or the detector switching element (50) is a fiber switch.

12. Device (22) according to one of the preceding claims, wherein the collector unit (48) comprises an integration sphere (55).

13. Device (22) according to one of the preceding claims, wherein the measuring system (28) has a unit (70) for performing a measurement of a surface resistance of the substrate (14), in particular for performing an eddy current measurement in the measuring area (40) of the substrate (14).

14. Device (22) for determining optical properties of an optically transparent substrate (14) which is provided on a first side (37) with a substrate coating (12), wherein the device (22) comprises a vacuum chamber (26) and a measuring system (28) with at least one measuring device (30), wherein the at least one measuring device (30) is arranged in the vacuum chamber (26), wherein the at least one measuring device (30) comprises a second measuring unit (36) which is associated with a second side (38) of the substrate (14) which is opposite the first side (37) of the substrate, wherein the second measuring unit (36) comprises a second emission unit (66) for irradiating a measuring area (40) of the substrate (14) associated with the measuring device (30) with directed electromagnetic radiation, wherein the measuring device (30) further comprises a first measuring unit (34) which is associated with the first side (37) of the substrate (14),wherein the first measuring unit (36) comprises a collector unit (48) which is configured to collect electromagnetic radiation emitted by the second emission unit (66) and transmitted through the substrate (14) in the measuring area (40), wherein the measuring system (28) further comprises a source (44) for electromagnetic radiation which is connected to the second emission unit (66) via a supply switching element (42), wherein the measuring system (28) further comprises a detector (52) which is connected to the collector unit (48) via a detector switching element (50), and wherein the source (44) for electromagnetic radiation and the detector (52) are arranged outside the vacuum chamber (26) of the device (22).

15. Coating system (10) for producing an optically transparent substrate (14) with a substrate coating (12) applied to a first side (37) of the substrate (14), comprising a device (22) for determining optical properties of the optically transparent substrate (14) according to one of the preceding claims.

16. Use of a measuring system (28) comprising at least one measuring device (30) with a first measuring unit (34) comprising a first emission unit (39) for irradiating a measuring area (40) of a substrate (14) associated with the measuring device (30) with directed electromagnetic radiation, and a collector unit (48) configured to collect electromagnetic radiation emitted by the first emission unit (39) and reflected by the substrate (14) in the measuring area (40), and / or comprising at least one measuring device (30) with a first measuring unit (34) and a second measuring unit (36), wherein the second measuring unit (36) comprises a second emission unit (66) for irradiating a measuring area (40) of a substrate (14) associated with the measuring device (30) with directed electromagnetic radiation, and wherein the first measuring unit (34) comprises a collector unit (48) configured toto collect electromagnetic radiation emitted by the second emission unit (66) and transmitted through the substrate (14) in the measuring area (40) for determining optical properties of the substrate (14), wherein the measuring system (28) further comprises a source (44) for electromagnetic radiation which is connected to the first emission unit (39) and / or the second emission unit (66) via a supply switching element (42), wherein the measuring system (28) further comprises a detector (52) which is connected to the collector unit (48) and / or the second collector unit (76) via a detector switching element (50), and wherein the at least one measuring device (30) is arranged in a vacuum chamber (26) of a device (22) according to one of claims 1 to 14 and the source (44) for electromagnetic radiation and the detector (52) are arranged outside the vacuum chamber (26) of the device (22).

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