Vacuum coating arrangement, control device and method for influencing the rate at which a coating material is emitted

Abstract

According to various embodiments, a method may comprise: determining a value representing an actual state of a rate at which a coating material is emitted, based on: a first response of a sensor (112) before the sensor (112) is exposed to the coating material and preferably heated thereby, and a second response of the sensor (112) after the sensor (112) has been exposed to the coating material and preferably cools down; and controlling an actuator configured to influence the rate based on the value.

Description

[0001] Various embodiments relate to a vacuum coating arrangement, a control device and a method for influencing a rate at which a coating material is emitted.

[0002] In general, a vacuum coating arrangement can be used to coat one or more substrates. The coating can be carried out, for example, by means of chemical vapor deposition or by means of physical vapor deposition, e.g., within a vacuum chamber. The coating rate, i.e. the rate at which the one or more substrates are coated with a coating material, depends on a rate at which the coating material is emitted (by a coating device) (also referred to as the emission rate). The coating rate can therefore be a function of this emission rate. The emission rate can depend on various disturbances within the vacuum chamber, so that the emission rate can change over time. It may therefore be necessary to counteract a change in the state of the system caused by such disturbances.To make this possible, it may be necessary to determine or record the current state of the rate (in-situ).

[0003] To determine the actual rate (in situ), a sensor such as a quartz crystal (e.g., in combination with an associated oscillator) can be used, which is exposed to the emitted coating material. For example, the resonant frequency of the quartz crystal changes depending on the mass of the coating material with which the sensor is coated. In this way, the magnitude of the frequency change per unit time can be used to determine the mass change per unit time, and this mass change per unit time is then a measure of the rate at which the coating material is emitted.

[0004] According to various embodiments, it has been recognized that sensors in general, such as such a quartz oscillator, which are exposed to the coating material, have a limited lifetime due to the coating material. If the mass of the coating material with which the sensor (e.g., quartz oscillator) is coated reaches a sensor-specific threshold, the sensor's function may be impaired or even no longer fulfilled.

[0005] However, depending on the sensor's lifetime, costs are not limited only by the cost of a new sensor. Since replacing the sensor at the end of its service life requires interrupting the coating process and / or opening the vacuum chamber, the sensor's lifetime also limits the efficiency of the vacuum coating system. For example, it limits the service life (the duration of uninterrupted production, also known as a campaign) of the vacuum coating system.

[0006] This wear and tear, or lifetime limitation, is explained herein using an easily understandable quartz crystal as an example rate sensor. What is described here can apply to any other sensor that is exposed to the coating material (e.g., during the measurement process), e.g., is coated by it. If, for illustration purposes, a certain (e.g., average) rate at which the sensor is coated is assumed for a coating process (e.g., an average change in mass per unit time), the lifetime of the sensor can be represented by the accumulated measurement time (or operating time). This accumulated measurement time can specify an accumulated (maximum) total operating time for which the sensor is capable of acquiring measurement data before its deterioration causes it to no longer meet requirements (thus reaching the end of its lifetime).Given a predefined time period per individual measurement, this (maximum) total operating time results in a (maximum) number of individual measurements. Depending on the intervals at which an individual measurement is performed, this can result in a (maximum) service life of the vacuum coating system.

[0007] Typically, a single measurement is taken while the sensor is being coated with coating material. However, a sensor response can be a function not only of the change in mass, but also of the sensor's temperature. Therefore, for a single measurement, it may be necessary to wait a predefined period of time until the sensor has reached thermal equilibrium (e.g., an invariant temperature) before a sensor response is used to determine the rate. This can have a significant impact, for example, in vacuum deposition setups where comparatively high coating rates are used (e.g., for coating organic substrates). Using the quartz crystal as an example, this predefined period of time can be approximately 2 minutes. Consequently, this predefined period of time leads to a minimum measurement time per single measurement.

[0008] Various embodiments relate to a vacuum coating arrangement, a control device and a method which make it possible to determine an actual state of a coating process (e.g. the rate at which a coating material is emitted, also referred to as emission rate) by means of a sensor in such a way (in situ) that the service life of the vacuum coating arrangement is significantly increased. This is made possible by reducing the time required for an individual measurement and / or for which the sensor is exposed to the coating material. Illustratively, the measuring process no longer (necessarily) takes place while the sensor is coated with coating material, but rather before and after, so that a first response of the sensor before the sensor is coated (and thereby heated) and a second response of the sensor after the sensor has been coated are evaluated.This eliminates the need to wait for the predefined time until thermal equilibrium is reached to mitigate the influence of temperature on the measurement process. This allows the time required for each individual measurement to be reduced by at least the predefined time. Consequently, this leads to a significantly longer service life of the vacuum deposition system.

[0009] To illustrate, a quartz oscillator can be considered as a sensor in a vacuum coating arrangement in which a coating material is emitted at a comparatively high rate. If, for example, a (maximum) total measurement duration of approximately 1 hour is assumed for the quartz oscillator, the predefined time period of approximately 2 minutes alone results in a maximum of 30 individual measurements. If each individual measurement is performed at intervals of 10 minutes, this results in a (maximum) service life of the vacuum coating arrangement of 5 hours. Since waiting for the predefined time period is not required according to the present invention, the coating time of the quartz oscillator can be 1 second (or less).With the same total measurement duration of 1 hour, this results in a maximum of 3600 individual measurements, and with time intervals of 10 minutes, a (maximum) lifetime of the vacuum coating system of 25 days (instead of 5 hours). Taking into account the phases in which the rate at which the quartz crystal is coated is lower (e.g., the phase in which a shutter is opened and / or the phase in which the shutter is closed), this lifetime is even longer (see, for example, . Fig. 3).

[0010] As explained above, what is described herein for a quartz crystal as an exemplary rate sensor can apply analogously to any sensor of other type (e.g. rate sensor) that is exposed to the coating material (e.g. during the measurement process), e.g. is coated by means of it.

[0011] Various examples are described below which relate to what is described herein and shown in the figures.

[0012] Example 1 is a method comprising: determining an indication representing an actual state of a rate (also referred to as emission rate) at which a coating material is emitted, or (more generally) a coating process (e.g., an operating parameter thereof) performed by means of the coating material, based on: a first response of a sensor before the sensor is exposed to the coating material and is preferably heated thereby (e.g., by means of the coating material and / or by thermal radiation), and a second response of the sensor after the sensor has been exposed to the coating material and is preferably cooled down (e.g., thereby); and controlling an actuator configured to influence the rate, or at least the coating process (e.g., the actual state, e.g., the operating parameter), based on the indication.

[0013] Example 1a is a method comprising: determining an indication representing an actual state of a process (e.g., coating process) performed, for example, using a coating material, based on: a first response of a sensor before the sensor is exposed to the process (e.g., the coating material thereof) and is preferably heated thereby, and a second response of the sensor after the sensor has been exposed to the process (e.g., the coating material thereof) and is preferably cooled down; and controlling an actuator configured to influence the process (e.g., coating process) based on the indication.

[0014] Example 2 is a method comprising: determining an indication representing an actual state of a rate at which a coating material of a coating process is emitted based on: a first response of a sensor before the sensor is exposed to the coating material and is preferably heated thereby, and a second response of the sensor after the sensor has been exposed to the coating material and is preferably cooled; and controlling an actuator configured to influence the coating process (e.g., the rate) based on the indication.

[0015] Example 3 is configured according to example 1 or 2, wherein determining the indication is further based on a period of time (e.g., a contiguous time interval) for which the sensor is exposed to the coating material (e.g., between the first response and the second response).

[0016] Example 4 is configured according to any one of examples 1 to 3, wherein the first response of the sensor occurs before the sensor is heated (e.g., by means of the coating material).

[0017] Example 5 is configured according to any one of Examples 1 to 4, wherein the second response of the sensor occurs when the sensor cools down or after the sensor has cooled down.

[0018] Example 6 is configured according to any one of Examples 1 to 5, wherein the sensor is not exposed to the coating material during the first response and / or the second response.

[0019] Example 7 is configured according to any one of Examples 1 to 6, wherein the first response and / or the second response of the sensor is a function of a temperature of the sensor; and / or wherein a period of time (e.g., a contiguous time interval) for which the sensor is exposed to the coating material ends before the sensor, when exposed to the coating material, has reached thermal equilibrium. For example, the period of time may end while the temperature of the sensor (e.g., the quartz crystal thereof) is changing, e.g., increasing (e.g., due to thermal power supplied to the sensor by the coating material).

[0020] Example 8 is configured according to any one of Examples 1 to 7, wherein a (eg, the) time period for which the sensor is exposed to the coating material is less than or equal to 60 seconds, preferably less than or equal to 10 seconds, further preferably less than or equal to 500 milliseconds.

[0021] Example 9 is configured according to any one of Examples 1 to 8, wherein the sensor comprises a quartz crystal that is exposed to (preferably coated by) the coating material.

[0022] Example 10 is configured according to any one of Examples 1 to 9, wherein the sensor is coated by the coating material when exposed to the coating material.

[0023] Example 11 is configured according to any one of Examples 1 to 10, wherein the first response and the second response are a function of a parameter (e.g., a resonant frequency) of the sensor (e.g., the quartz crystal) that is changed when the sensor is exposed to the coating material, the parameter optionally further depending on a temperature of the sensor.

[0024] Example 12 is configured according to any one of Examples 1 to 11, further comprising: detecting the first response of the sensor, preferably at the time before the beginning of the time period (e.g., the contiguous time interval); and / or detecting the second response of the sensor, preferably at the time after the end of the time period (e.g., the contiguous time interval).

[0025] Example 13 is configured according to any one of Examples 1 to 12, further comprising: controlling an actuator configured to influence a (eg the) time period for which the sensor is exposed to the coating material (between the first response and the second response) and / or an amount of the coating material (also referred to as material amount) to which the sensor is exposed between the first response and the second response, eg according to an indication representing a desired state of the time period and / or the amount, eg a mass flow of the coating material.

[0026] Example 14 is configured according to Example 13, wherein the indication is further determined based on one or more additional indications (e.g., comprising time dependence of the mass flow rate, mean value of the mass flow, and / or switching time, etc.) over at least a portion of the time period for which a mass flow (amount of material per time) of the coating material to which the sensor is exposed is time dependent.

[0027] Example 15 is configured according to Example 14, wherein the at least one portion comprises or is at least a function of a switching time of a shutter; and / or wherein the mass flow is a function of a position of the shutter relative to the sensor.

[0028] Example 16 is configured according to Example 15, wherein the at least one portion comprises a first portion having a switching time for opening the shutter, or at least being a function thereof, and a second portion having a switching time for closing the shutter, or at least being a function thereof; and / or wherein the at least one portion (e.g., the first portion and / or second portion) is a function of a speed at which the shutter is moved (e.g., rotated).

[0029] Example 17 is configured according to example 15 or 16, wherein the switching time of the shutter is less than or equal to one-third of a time interval of the second response from the first response and / or one-third of the time duration.

[0030] Example 18 is configured according to one of examples 13 to 17, wherein the actuation of the actuator is carried out according to a (e.g. stored) target time period (e.g. target switching time).

[0031] Example 19 is configured according to any one of Examples 1 to 18, if in combination with Example 3 and / or 13, further comprising: detecting the duration of time for which the sensor is exposed to the coating material, preferably a duration of a switching (i.e., a switching time) of the shutter and / or preferably by means of one or more than one additional sensor.

[0032] Example 20 is configured according to any one of examples 1 to 19, wherein, when determining the indication, a time dependence of a mass flow of the coating material to which the sensor is exposed is further taken into account; wherein, preferably, the time dependence is taken into account as an average value of the time dependence of the mass flow.

[0033] Example 21 is configured according to any one of Examples 1 to 20, when in combination with Example 3 and / or 13, wherein the time period comprises: a first phase in which the sensor is moved into the emitted coating material (e.g., linearly, by rotation, etc.) or in which a (e.g., the) shutter is brought from a first state in which the sensor is not exposed to the coating material to a second state in which the sensor is exposed to the coating material; and a second phase in which the sensor is moved out of the emitted coating material or in which the shutter is brought from the second state to the first state.

[0034] Example 22 is configured according to Example 21, wherein the indication is further determined based on a duration of the first phase and / or a duration of the second phase.

[0035] Example 23 is configured according to any one of Examples 1 to 22, wherein the sensor is not exposed to the coating material for a time interval until the second response (e.g., after the time period).

[0036] Example 25 is a computer program configured, when executed by a processor, to cause the processor to perform the method of any one of Examples 1 to 23.

[0037] Example 25 is a computer-readable medium storing instructions configured, when executed by a processor, to cause the processor to perform the method of any of Examples 1 to 23.

[0038] Example 26 is a control device comprising one or more than one processor configured to perform the method of any of Examples 1 to 23.

[0039] Example 27 is a vacuum coating assembly comprising: the control device according to Example 26; a coating device for emitting the coating material; the actuator for controlling the coating device; and the sensor.

[0040] Example 28 is configured according to Example 27, wherein the coating device is configured to perform a chemical vapor deposition process and / or physical vapor deposition process.

[0041] In Example 29, the vacuum coating assembly according to Example 27 or 28 may optionally further comprise: a shutter configured such that, depending on a state of the shutter, the sensor is either exposed or not exposed to the coating material upon emission of the coating material by means of the coating device; and a drive device for adjusting the state of the shutter.

[0042] In Example 30, the vacuum coating assembly according to any one of Examples 27 to 29 can optionally further comprise: a vacuum chamber in which the coating device and the sensor are arranged.

[0043] In Example 31, the vacuum coating assembly according to any one of Examples 27 to 30 can optionally further comprise: the actuator configured to influence the length of time for which the sensor is exposed to the coating material between the first response and the second response and / or the amount of coating material to which the sensor is exposed between the first response and the second response.

[0044] It shows Fig. 1 shows a vacuum coating arrangement with a sensor for determining (and optionally influencing) a rate at which a coating material is emitted, according to various embodiments, in a schematic plan view or side view; Fig. 2 an illustrative comparison of a measuring method according to the prior art and a measuring method according to various embodiments; and Fig. 3 is a diagram showing different phases of a time period in which a sensor is coated with coating material, according to various embodiments.

[0045] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology such as "top," "bottom," "front," "back," "fore," "rear," etc., will be used with reference to the orientation of the described figure(s). Since components of embodiments can be positioned in a number of different orientations, the directional terminology is for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention.It is understood that the features of the various exemplary embodiments described herein may be combined with one another unless specifically stated otherwise. The following detailed description is therefore not to be construed in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0046] Throughout this description, the terms "connected," "attached," and "coupled" are used to describe both a direct and an indirect connection (e.g., resistive and / or electrically conductive, e.g., an electrically conductive connection), a direct or indirect connection, and a direct or indirect coupling. In the figures, identical or similar elements are provided with identical reference numerals where appropriate.

[0047] According to various embodiments, the term "coupled" or "coupling" can be understood in the sense of a (e.g., mechanical, hydrostatic, thermal, and / or electrical), e.g., direct or indirect, connection and / or interaction. For example, several elements can be coupled to one another along an interaction chain, along which the interaction can be exchanged, e.g., a fluid (then also referred to as fluidically coupled). For example, two coupled elements can exchange an interaction with one another, e.g., a mechanical, hydrostatic, thermal, and / or electrical interaction. A coupling of several vacuum components (e.g., valves, pumps, chambers, etc.) to one another can include fluidically coupled ones. According to various embodiments, "coupled" can be understood in the sense of a mechanical (e.g., physical) coupling, e.g.,by means of direct physical contact. A clutch can be configured to transmit a mechanical interaction (e.g., force, torque, etc.).

[0048] In the context of vacuum components (e.g., a pump, a chamber, a line, a valve, etc.), the term "coupled" or "coupling" can be understood in the sense of a connection to a common vacuum system. The components of the vacuum system can be configured to exchange a gas with each other via the coupling, whereby the coupling can be gas-separated from an external part of the vacuum system.

[0049] The actual state of an entity (e.g., a device, a system, or a process) can be understood as the actual or sensorily detectable state of the entity. The desired state of the entity can be understood as the desired state, i.e., a specification. Control can be understood as an intentional influencing of the current state (also referred to as the actual state) of the entity. The current state can be changed according to the specification (also referred to as the desired state), e.g., by changing one or more operating parameters (then also referred to as manipulated variables) of the entity, e.g., by means of an actuator. Regulation can be understood as controlling, whereby a change in state is additionally counteracted by disturbances. For this purpose, the actual state is compared with the desired state, and the entity is influenced in such a way, e.g.,by means of an actuator, so that the deviation of the actual state from the desired state is minimized. In contrast to pure forward-directed sequential control, the control thus implements a continuous influence of the output variable on the input variable, which is effected by the so-called control loop (also referred to as feedback). In other words, this can be understood as meaning that, alternatively or in addition to open-loop control (or actuation), closed-loop control can be used, or, alternatively or in addition to open-loop control, closed-loop control can be used.

[0050] The state of a controllable device (e.g. a structuring device) or a controllable process (e.g. structuring) can be specified as a point (also referred to as the working point or operating point) in a space (also referred to as the state space) spanned by the variable parameters of the device or process (also referred to as operating parameters). The state of the device or process is thus a function of the respective value of one or more operating parameters, which thus represents the state of the device or process. The actual state can be determined based on a measurement (e.g. using a measuring element) of one or more operating parameters (then also referred to as the controlled variable).

[0051] The term "control device" can be understood as any type of logic-implementing entity, which may, for example, comprise circuitry and / or a processor capable of executing software stored in a storage medium, firmware, or a combination thereof, and issuing instructions based thereon. The control device can, for example, be configured using code segments (e.g., software) to control the operation of a system (e.g., its operating point), e.g., a machine or a system, e.g., at least its kinematic chain.

[0052] Control can be understood as the intentional influencing of a system. The current state of the system (also referred to as the actual state) can be changed according to a specification (also referred to as the target state). The parameters of the target state explained here (also referred to as target parameters) can, for example, be implemented using code segments or can be stored on a storage medium in some other way. Regulation can be understood as control, whereby a change in the state of the system is additionally counteracted by disturbances. Illustratively, the control system can have a forward-facing control path and thus clearly implement a sequential control that converts an input variable (e.g. the specification) into an output variable. However, the control path can also be part of a control loop, so that a closed-loop control is implemented.For control purposes, corresponding actuators of the system can be activated, which influence the actual state of the system. Examples of actuators include: a drive device (e.g., for providing torque), a valve (e.g., for controlling pressure), a switch (e.g., for closing a discharge path). The drive device can, for example, comprise a linear drive (e.g., a reciprocating piston) or an electric motor.

[0053] If reference is made herein to a target parameter (e.g. a target rate at which a coating material is to be emitted), this can be implemented by means of code segments which can be stored, for example, in a data memory belonging to the control device. The code segments can be stored in the data memory in a suitable manner, for example as a list (e.g. table), series of values, as an algorithm, etc. A data memory (more generally also referred to as a storage medium) can, for example, be a non-transitory data memory. The data memory can, for example, comprise or be formed from a hard disk and / or at least one semiconductor memory (such as read-only memory, random access memory and / or flash memory). The read-only memory can, for example, be an erasable programmable read-only memory (can also be referred to as EPROM).The random access memory can be a non-volatile random access memory (also known as NVRAM - “non-volatile random access memory”).

[0054] The term “actuator” (e.g. having an actuator) can be understood as a transducer that is configured to influence a state, a process (e.g. a coating process) or a device in response to actuation of the actuator. The actuator can convert a control signal supplied to it (by means of which the actuation takes place) into mechanical movements or changes in physical quantities such as pressure or temperature. An electromechanical (also referred to as an electromotive) actuator can, for example, be configured to convert electrical power into mechanical power (e.g. through movement) in response to the actuation. An electrothermal actuator can, for example, be configured to convert electrical power into thermal power in response to the actuation.An electrothermal actuator can, for example, be configured to convert electrical power into thermal power in response to the control. An electrical actuator can, for example, be configured to convert electrical energy into electrical energy (e.g., of a specific voltage, current, and / or power) in response to the control.

[0055] An actuator can be configured to influence the actual state (also referred to as the operating point) of the process (e.g., its manipulated variable), which is supplied by the actuator. This influence can be direct or indirect. For example, the manipulated variable and the controlled variable can differ from each other. The controlled variable (e.g., pressure) can then be a function of one or more manipulated variables (e.g., voltage).

[0056] For example, the actuator can change an electrical voltage as a control variable, which supplies a coating device for emitting coating material, so that the rate at which the coating material is emitted and, consequently, the coating rate (i.e., the rate at which a substrate is coated) or the layer thickness are changed as a control variable. For example, the actuator can change the inflow rate of a gas as a control variable, so that the pressure is changed as a control variable.

[0057] Examples of components of an actuator include: a coating device, a valve (e.g., a pump arrangement and / or gas supply device), a motor (e.g., a valve or a pump), a circuit (e.g., for controlling the coating device), a drive device (e.g., for controlling a state of a shutter), or the like. The coating device can, for example, be configured to carry out a coating process according to the control. The pump arrangement can, for example, be configured to pump out one or more gases according to the control and thus remove them from the coating process. The gas supply device can, for example, be configured to supply one or more gases to the coating process according to the control (also referred to as supplying gas). The supplied gas can have a gas inflow rate (e.g., gas inflow per time).The gas inflow can, for example, be a standard volume flow supplied to the coating process.

[0058] With regard to the control of an actuator, reference is made, among other things, to the more easily understood manipulated variable or its control value, which is influenced by the actuator. What has been described here can apply analogously to the controlled variable or its control value, which are fed to the actuator for control, and vice versa. The actuator acts as a converter, converting a control signal into the manipulated variable or its control value, so that the control value is a function of the control value. Modern actuators, for example, are provided as a complex assembly comprising an actuator and its own control device (also referred to as an actuator control device). The actuator control device can be configured to receive the control value as input using the control signal and to control the actuator according to the control value.The generation and transmission of the control variable then takes place within the actuator, so that the manipulated variable is fed to the actuator. Less complex actuators can only process the control variable as a control signal, so the control variable is fed to them for control.

[0059] More generally, an actuator can be controlled using a control signal, where the control signal can represent the manipulated variable or its control value and / or the controlled variable or its control value. Alternatively or additionally, the control signal can contain instructions that specify how the manipulated variable or its control value is to be changed (e.g., its relative change).

[0060] Control performed by the control device can be carried out according to an operating sequence. This operating sequence can be stored in the data memory in a suitable manner, for example, as an algorithm or in another way using code segments. An operating sequence is understood herein to be a specification according to which one or more actuators configured to influence the rate at which a coating material is emitted are controlled. The operating sequence can specify one or more target parameters according to which the coating material is emitted at that rate.

[0061] A sensor (also referred to as a detector) can be understood as a transducer which is set up to detect a property of its environment (e.g. qualitative or quantitative) corresponding to the sensor type as a measured variable, e.g. a physical property, a chemical property and / or a material condition. The measured variable is the physical variable (then also referred to as the controlled variable) to which the measurement by means of the sensor applies. Each sensor can be part of a measuring chain which has a corresponding infrastructure (e.g. processor, storage medium and / or bus system and the like). The measuring chain can be set up to control the corresponding sensor, to process its detected measured variable as an input variable and, based thereon, to provide an electrical signal as an output variable which represents the detected input variable. For example, the output variable can indicate the measured value.The measuring chain can be implemented, for example, by means of a so-called control device. Various embodiments are directed to a sensor that is coated with a coating material, wherein the measured variable of the sensor can be a function of the mass of the coating material with which the sensor is or will be coated.

[0062] Reference is made herein to the control and / or regulation of a coating process, which can be effected, for example, by actuating one or more actuators (also referred to as actuating intervention). In this context, reference is also made to a control device or code segments. The control device (also referred to as a regulating device) can be configured to implement one or more of the methods described herein (or at least one process thereof). For this purpose, the control device can have a processor configured to implement the respective method. For example, the processor can be configured to output corresponding instructions for actuation. Alternatively or additionally, the processor can be configured to receive and process corresponding instructions and signals.The instructions received by the processor can be implemented, for example, using code segments stored on a non-transitory data memory. For example, the code segments can include at least one instruction and / or one or more specifications that, when executed by the processor, cause the processor to perform one of the methods.

[0063] The term "processor" can be understood as any type of entity that allows the processing of data or signals. The data or signals can, for example, be processed according to at least one (i.e., one or more than one) specific function performed by the processor. A processor can include or be formed from an analog circuit, a digital circuit, a mixed-signal circuit, a logic circuit, a microprocessor, a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a programmable gate array (FPGA), an integrated circuit, or any combination thereof.Any other type of implementation of the respective functions, which are described in more detail below, can also be understood as a processor or logic circuit, for example virtual processors (or a virtual machine) or a plurality of decentralized processors, which are connected to one another, for example by means of a network, are spatially distributed in any way and / or have any share in the implementation of the respective functions (e.g. distribution of the computing load among the processors). The same generally applies to differently implemented logic for implementing the respective functions. It is understood that one or more of the method steps described in detail herein can be carried out (e.g. realized) by a processor, by one or more specific functions carried out by the processor.

[0064] With regard to the movement process, e.g., of the sensor, reference is made to the direction of movement. The direction of movement refers to the direction of movement, e.g., the direction of translation (also referred to as the translation direction) or rotation (also referred to as the rotation direction). Translation can, for example, occur along a linear path, e.g., in sections, that is parallel to the translation direction (direction of translation). If the movement proceeds along a closed path that follows the rotation direction, this is also referred to as orbital movement.

[0065] A drive device can be understood herein as a converter configured to convert (e.g., electrical) energy into mechanical energy. A drive device can, for example, comprise an electric motor (e.g., with electrical coils). A drive device can, for example, comprise a compressor and a reciprocating piston coupled thereto. A drive device can, for example, comprise one or more piezoelectric elements. For example, the drive device can be configured to output the mechanical energy by means of a torque or a rotational movement.

[0066] The expression that an element, a parameter, etc. “represents” another element, another parameter, etc. can be understood to mean that the element or parameter is a (e.g. one-to-one) function of the other element or parameter.

[0067] Fig. 1 illustrates a vacuum coating arrangement 100 according to various embodiments in a schematic top view or side view.

[0068] The vacuum coating arrangement 100 can have a vacuum chamber 102. A vacuum chamber 102 can be provided, for example, by means of a chamber housing in which one or more vacuum chambers can be provided. The chamber housing can be coupled, for example, to a pump arrangement, e.g., a vacuum pump arrangement, for providing a negative pressure or a vacuum (vacuum chamber housing), and can be designed so stably that it withstands the effects of air pressure in the pumped-out state. The pump arrangement (comprising at least one vacuum pump, e.g., a high-vacuum pump, e.g., a turbomolecular pump) can make it possible to pump out part of the gas from the interior of the vacuum chamber 102. The or each vacuum chamber 102 can optionally have a chamber lid that seals the interior of the vacuum chamber 102 in a vacuum-tight manner. The plasma of the arc discharge can accordingly create a negative pressure (e.g.,a vacuum).

[0069] The chamber housing, e.g. a vacuum chamber 102 provided therein, may be configured such that a negative pressure (ie a pressure less than atmospheric pressure) can be provided therein, e.g. a vacuum (ie a pressure of less than 0.3 bar), e.g. a pressure in a range of approximately 10 mbar to approximately 1 mbar (in other words rough vacuum) or less, e.g. a pressure in a range of approximately 1 mbar to approximately 10 -3 mbar (in other words fine vacuum) or less, e.g. a pressure in a range of approximately 10 -3 mbar to approximately 10 -7 mbar (in other words high vacuum) or less, e.g. a pressure less than high vacuum, e.g. less than about 10 -7 mbar. Atmospheric pressure (e.g., 1 bar) can be the pressure acting on the chamber housing from the outside.

[0070] The vacuum coating arrangement 100 may include a coating device 104. The coating device 104 may be configured to emit a coating material. For this purpose, the coating device 104 may be any suitable type of coating device capable of emitting a coating material. According to various embodiments, the coating device 104 may be configured to perform a chemical vapor deposition process and / or a physical vapor deposition process. For example, the coating device 104 may include a magnetron (a planar magnetron or a tubular magnetron). For example, the coating device 104 may include an electron beam evaporator. For example, the coating device 104 may be configured to perform a spray coating or a spray coating process.For example, the coating apparatus 104 may include a nozzle tube evaporator for providing one or more evaporation sources. It is understood that these are exemplary embodiments of the coating apparatus 104 and that it may also include or be any other type of apparatus for performing a chemical vapor deposition process and / or a physical vapor deposition process.

[0071] The gas pressure used to operate the coating device 104 (also referred to as operating pressure) and / or the gas or gas mixture supplied to the coating device 104 (also referred to as operating gas) can be highly application-dependent. For example, the operating pressure can be in a range of approximately 10 -4 mbar (millibar) to approximately 5·10 -4mbar. For example, the operating gas may comprise one or more of the following gases: oxygen (e.g., molecular oxygen, i.e., O2), nitrogen (e.g., molecular nitrogen, i.e., N2), hydrogen (e.g., molecular hydrogen, i.e., H2), one or more hydrocarbon compounds, or a gas mixture thereof. The operating gas may comprise the working gas (e.g., an inert gas) and / or a reactive gas. The reactive gas may, for example, comprise hydrogen.

[0072] The coating device 104 may include a target. The target may generally include or consist of the coating material. The coating material emitted by the coating device 104 (e.g., dissolved from the target) may form a material stream 106 (e.g., away from the target).

[0073] During operation of the vacuum coating arrangement 100, one (or more than one) substrate 110 can be coated by means of the material flow 106. For this purpose, the vacuum coating arrangement 100 can have a substrate holder 108 configured to hold the one or more than one substrate 110. The substrate holder 108 can be arranged in the vacuum chamber 102. In some embodiments, the substrate holder 108 can be stationary. In other embodiments, the substrate holder 108 can be movable. For example, the vacuum coating arrangement 100 can be a continuous-flow system that has a transport system for transporting the substrate 110. In general, a continuous-flow system can have two substrate transfer openings through which at least one substrate can be guided into and out of the continuous-flow system. Several processing areas can be configured between these two substrate transfer openings.For example, one or more of the processing areas may each have one or more coating devices.

[0074] The or each substrate may generally comprise a workpiece, e.g., a semi-finished product (e.g., a rod, sleeve, or plate) or a component of a more complex device. Examples of a substrate include: a piston ring, a bearing component, a tool, a chain, a drive chain, an obtuse-angled geometry, a knife, or a sliding friction-sensitive component. The or each substrate may, for example, be cylindrical, plate-shaped, or have another shape.

[0075] The or each substrate may comprise or be formed from at least one of the following: a ceramic, a glass, a semiconductor (e.g., amorphous, polycrystalline, or single-crystal semiconductor such as silicon), a metal, and / or a polymer (e.g., plastic). The ceramic may, for example, comprise an oxide, a nitride, and / or a carbide of a metal.

[0076] In the context of this description, a metal (also referred to as a metallic material) can comprise (or be formed from) at least one metallic element (i.e. one or more metallic elements), e.g. at least one element from the following group of elements: copper (Cu), iron (Fe), titanium (Ti), nickel (Ni), silver (Ag), chromium (Cr), platinum (Pt), gold (Au), magnesium (Mg), aluminum (Al), zirconium (Zr), tantalum (Ta), molybdenum (Mo), tungsten (W), vanadium (V), barium (Ba), hafnium (Hf), samarium (Sm), silver (Ag), and / or lithium (Li). For example, a metal can comprise or be formed from a metallic compound (e.g. an intermetallic compound or an alloy) or a compound of at least one metallic element (e.g. from the group of elements) and at least one non-metallic element (e.g. carbon), such as steel.

[0077] The vacuum coating arrangement 100 may include a control device 118. The control device 118 may be configured to control the coating device 104. For example, the control device 118 may control the coating device 104 according to one or more manipulated variables (e.g., an electrical voltage) in order to set a target rate at which the coating material is to be emitted as a controlled variable. The material flow 106 thus generated may have an actual rate at which the coating material is emitted (i.e., an actual rate of the material flow 106). The actual rate of the material flow 106 may be a quantity of material per time (e.g., per unit time).

[0078] During operation, a portion of the material stream 106 may impinge on the substrate 110. This portion of the material stream 106 may therefore indicate an actual rate at which the substrate 110 is coated. This actual rate at which the substrate 110 is coated may also be referred to as the coating rate. Consequently, the coating rate may be understood as an amount of coating material impinging on the substrate 110 per unit of time, or an amount of coating material deposited (separated) on the substrate 110 per unit of time. The coating rate may also be viewed as the growth rate (layer thickness change per unit of time) of a layer on the substrate 110. A quantity of material per unit of time of the material stream 116 may also be referred to as mass flow and / or mass flow.

[0079] However, the actual rate of the material flow 106 may depend on various disturbances within the vacuum chamber 102, such as a temperature of the target, the pressure within the chamber, a gas flow of a supplied gas or gas mixture, etc.

[0080] Therefore, it may be necessary to regulate the rate at which the coating material is emitted. For this purpose, the control device 118 can be configured to regulate this rate based on the actual rate of the material flow 106 using the manipulated variable (e.g., the electrical voltage) in order to set the target rate as a controlled variable.

[0081] For this purpose, the vacuum coating arrangement 100 can have a sensor 112 (e.g., arranged in the vacuum chamber 102). The sensor 112 can be configured to provide a response that is a function of the mass of coating material with which the sensor is coated. Consequently, the sensor can be configured such that its response changes when the sensor is exposed to the coating material. An example of this is a quartz crystal. In some embodiments, the sensor 112 can have the quartz crystal and an associated oscillator. In other embodiments, the control device 118 can have the associated oscillator. In the case of the quartz crystal, the resonant frequency of the quartz crystal changes depending on the mass of the coating material with which the quartz crystal is coated. This change in the resonant frequency can be detected directly or indirectly.For example, the change in the resonant frequency can be detected indirectly by measuring the (frequency-dependent) impedance of the quartz oscillator. When referring to the resonant frequency of the quartz oscillator, it is understood that this resonant frequency only develops (during operation) in the oscillating circuit (i.e., after applying a corresponding signal).

[0082] According to various aspects, the response of sensor 112 may further be a function of a temperature of sensor 112. Thus, the response of sensor 112 may change depending on the temperature of sensor 112.

[0083] Herein, in various illustrative examples, reference is made to a quartz crystal as sensor 112. It is understood that this is for illustrative purposes, and that sensor 112 may also comprise any other type of sensor in which a response of the sensor is a function of the mass of coating material with which the sensor is coated, and optionally further, the temperature of the sensor.

[0084] According to various aspects, during operation, the sensor 112 may be exposed to the coating material, i.e., the material stream 106, for a specific period of time to determine the actual rate at which the coating material is emitted (or at least an indication representative of this actual rate). In some embodiments, the sensor 112 may be stationary within the vacuum chamber 102, and a shutter may be used to expose the sensor 112 to the material stream 106 or to block the material stream 106. In other embodiments, the sensor 112 may be moved into (and out of) the material stream 106 to be exposed thereto. For illustrative purposes, reference will be made below to the shuttered embodiment. It is understood that the principle described herein may be applied accordingly to embodiments in which the sensor 112 is moved into the material stream 106.

[0085] The vacuum coating assembly 100 may include a shutter 114 (also referred to as a shutter). The shutter 114 may be configured such that the sensor 112 is either exposed or not exposed to the coating material of the material stream 106, depending on a state of the shutter 114. For example, the shutter 114 may have at least a first state in which the sensor 112 is not exposed to the coating material (i.e., in which the material stream 106 is blocked) and at least a second state in which the sensor 112 is exposed to the coating material. The vacuum coating assembly 100 may include a drive device 116 configured to adjust the state of the shutter 114.

[0086] Here, the closure panel 114 can have any type of closure panel by means of which the sensor 112 is either exposed or not exposed to the material flow 106 depending on a state of the closure panel. Accordingly, the drive device 116 can be any type of device by means of which a state of the closure panel 114 can be changed. The control device 118 can be configured to control the drive device 116. Consequently, the control device 118 can be configured to control a state of the closure panel 114 (by means of the drive device 116). Therefore, the control device 118 can be configured to control a period of time for which the sensor 112 is exposed to the coating material (e.g., according to a target period of time).

[0087] In one example, the shutter 114 and the drive device 116, which is of a pneumatic type, can provide a pneumatic shutter system in which the state of the shutter 114 depends on whether compressed air is applied or not. In an advantageous embodiment, the shutter 114 can be a shutter that can be rotated by means of the drive device 116 from one of the at least one first state in which the sensor 112 is not exposed to the coating material (i.e., in which the material flow 106 is blocked) to one of the at least one second state in which the sensor 112 is exposed to the coating material, and vice versa. For example, the shutter 114 can be a shutter that has two first states and two second states.In this case, for example, a quarter turn of the shutter 114 driven by the drive device 116 can take place from a first state to the second state, by means of a subsequent quarter turn of the shutter 114, the shutter 1114 can be rotated from the second state to the other first state, and by means of a further subsequent quarter turn of the shutter 114, the shutter 1114 can then be rotated from the other first state to the other second state. Consequently, the shutter 114 can be rotatably mounted. The shutter 114 can, for example, have a diameter in a range of approximately 50 mm to approximately 300 mm (e.g., approximately 100 mm). According to various embodiments, the drive device 116 can be a stepper motor or can comprise one.It is understood that this is an exemplary embodiment of the shutter 114 and serves for illustration purposes. The embodiment in which the shutter 114 is rotatably mounted with the at least one first state and the at least one second state and in which the drive device 116 has a stepper motor can be advantageous over pneumatic shutter systems due to a shorter switching time, since this allows a significantly shortened time duration for an individual measurement. For example, in one embodiment, the rotatably mounted shutter 114 can be a rotatably mounted disk. In another embodiment, the rotatably mounted shutter 114 can have or be a rotating element (e.g., a belt and / or wheel).This circumferential element may have one or more openings so that an opening can provide a corresponding second condition in which the sensor 112 can be exposed to the coating material.

[0088] As an alternative to the rotatable mounting, the shutter can be mounted so that it can move translationally, for example.

[0089] It can be understood that what is described herein by way of example regarding the functioning of the shutter can apply analogously to any other type of implementation of a (multiply repeated) measurement sequence, which has a first phase in which the sensor is exposed to the coating process for a period of time 220, and a second phase in which the sensor is shielded from the coating process for an additional period of time (also referred to as a measurement pause). For example, the measurement sequence can be implemented by means of a shutter that is moved (translationally or rotationally) relative to the source of the coating material relative to a sensor that is stationary relative to the source of the coating material. For example, the measurement sequence can be implemented by means of a support on which the sensor is mounted and that is moved (translationally or rotationally) relative to the source of the coating material.For example, the movement of multiple shutters can be superimposed to implement the shortest possible time period 220. For example, instead of one shutter, multiple shutters of different geometries can be used to change the time period 220.

[0090] Fig. 2 shows an illustrative comparison of a measurement method according to the prior art and a measurement method according to various embodiments. This exemplary illustration relates to a sensor 112 having a quartz oscillator, which is why diagram 200 shows a (resonance) frequency, F, of the quartz oscillator as a function of time, t. It is understood that the quartz oscillator is an example of the sensor 112 and that, in the case of a different sensor, a parameter other than frequency may be detected. Also, the frequency, F, of the quartz oscillator is merely an exemplary parameter for the quartz oscillator. In other embodiments, a (frequency-dependent) impedance of the quartz oscillator may be detected as a parameter.

[0091] Diagram 200 shows a first frequency response 202 according to the prior art. Initially (i.e., before time t0), the shutter 114 may be in the first state in which the sensor 112 is not exposed to the coating material (i.e., in which the material flow 106 is blocked), and a response from the sensor 112 may have an output frequency 206. At time t0, the shutter 114 may be opened, exposing the sensor 112 to the coating material. The resulting change in mass of coating material deposited on the sensor 112 may lead to a decrease in the frequency, F. The energy input of the coating material may heat the sensor 112. As described herein, the response of the sensor 112, i.e., in this example, the frequency F, may be a function of the temperature of the sensor 112. Increasing the temperature may lead to an increase in the frequency, F.This can lead to the reduction in frequency, F, caused by the change in mass not being recorded. This increasing frequency is clearly shown in diagram 200. For this reason, it may be necessary to wait a predefined period of time 212 (from time t0 to time t2) until the sensor 112 has reached thermal equilibrium (see light gray area). This predefined period of time can also be considered a dead time, since during this time the sensor's response cannot be used to determine the rate. Subsequently, in a subsequent measuring interval 214 (from time t2 to time t3), a change in frequency over time can be recorded as a measure of the change in mass over time (see dark gray area). At time t3, the shutter 114 can then be closed to no longer expose the sensor 112 to the coating material, allowing it to cool down.After the sensor 112 has cooled down, it may have a reduced final frequency 208 due to the change in mass (compared to the initial frequency 206), which, however, is conventionally no longer detected. As described herein, the predefined time period 212 may be several minutes. The measurement duration 210 for a single measurement may therefore require at least these several minutes.

[0092] Diagram 200 further shows a second frequency curve 204 according to various embodiments. Here, at a time t A1 , which is before time t0, a first response of the sensor 112 can be detected. For example, the control device 118 can be configured to detect the sensor 112 at time t A1to detect the first response. The first response can thus be detected while the shutter 114 is closed and the sensor 112 is thus not exposed to the coating material. Consequently, the first response can be detected before the sensor 112 is heated (e.g., by means of the coating material).

[0093] The control device 118 may be configured to control the drive device 116 to open the shutter 114 at time t0 and thus expose the sensor 112 to the coating material. This may cause the sensor 112 to heat up. According to various embodiments, the control device 118 may be configured to control the drive device 116 to close the shutter 114 at time t1 (or the closing may be completed at time t1, see Fig. 3) and thus no longer expose the sensor 112 to the coating material. This allows the sensor 112 to cool down.

[0094] According to various embodiments, the control device 118 may be configured to control the sensor 112 at time t A2 to detect a second response of the sensor 112. The time t A2 may be after time t2. Consequently, the second response may also be detected while the shutter 114 is closed and the sensor 112 is thus not exposed to the coating material. In this case, the second response may be detected after the sensor 112 has been exposed to the coating material. Consequently, the sensor 112 may be exposed to the coating material for a period of time 220. In principle, between time t2 and the detection of the second response at time t A2 any length of time as long as the shutter 114 remains closed.

[0095] The controller 118 may be configured to detect the mass change based on the first response and the second response (e.g., based on the difference between a frequency 206 associated with the first response and a frequency associated with the second response). The controller 118 may be configured to determine a mass change over time based on the mass change and the time period 220 for which the sensor 112 is exposed to the coating material. The controller 118 may be configured to determine, based on the mass change over time, an indication representing the actual state of the rate at which the coating material is emitted.

[0096] The control device 118 can be configured to control the drive device 116 according to a (e.g., stored) target time period for which the sensor 112 is to be exposed to the coating material. In some embodiments, the control device 118 can be configured to determine the indication of the actual state of the rate based on this target time period. In other embodiments, the vacuum coating arrangement 100 can have one or more additional sensors to detect time t0 and / or time t1. In this case, the control device 118 can be configured to determine the time period 220 as the time difference between these detected times.

[0097] The control device 118 may be configured to control the coating device 104 to regulate the coating process, for example, such that a deviation between the actual state of the rate and the desired state of the rate is reduced.

[0098] Since the first response and the second response are detected while the shutter 114 is closed and the sensor 112 is therefore not coated, it is no longer necessary to wait for the predefined time period 212 compared to the prior art measurement method. Consequently, the time period for which the sensor 112 is exposed to the coating material (also referred to as the coating time) can end before the sensor 112 has reached thermal equilibrium. In this way, the coating time can be significantly reduced. For example, the time period 220 for which the sensor 112 is exposed to the coating material can be less than or equal to 60 seconds (e.g., less than or equal to 30 seconds, e.g., less than or equal to 10 seconds, etc.).

[0099] The reduced time period 220 for which the sensor 112 is exposed to the coating material also results in a smaller temperature increase of the sensor 112 due to the energy introduced by the coating material, thereby improving adhesion of the coating material to the sensor 112 (and thus reducing particle formation and re-evaporation of material deposited on the sensor 112) and thereby further increasing the service life of the vacuum coating arrangement 100.

[0100] According to various aspects, the time period 220 for which the sensor 112 is exposed to the coating material may be less than or equal to 1 second (e.g., less than or equal to 500 milliseconds, e.g., less than or equal to 100 milliseconds). However, in this case, the duration of a switching (i.e., a switching time) of the shutter 114 from one state to another state may have a relevant influence on determining the rate.

[0101] The switching time refers to the time required to move the shutter 114 from a closed state (in which the sensor is shielded from the coating material) to an open state (in which the sensor is exposed to the coating material) or vice versa. Clearly, the opening or closing of the shutter 114 may require a certain amount of time (the so-called switching time), and during this time the rate may be time-dependent. Thus, the rate at which the sensor 112 is coated may be time-dependent (and reduced) for a period of time during which the shutter 114 is opened (also referred to as the opening period) and / or a period during which the shutter 114 is closed (also referred to as the closing period). According to various embodiments, the control device 118 may be configured to take this time dependence of the rate at which the sensor 112 is coated into account when determining the indication.It is understood that the opening and closing of the shutter 114 is exemplary. For example, if the sensor 112 is moved into the material stream 106 and then back out again, the rate at which the sensor 112 is coated may be time-dependent for a period of time moving into the material stream 106 and for a period of time moving out of the material stream 106.

[0102] Fig. 3 shows a diagram 300 with various phases of the time period 220 according to various embodiments. With regard to the time period 220, reference is made here to an easily understandable notation in the form of a time difference (Δt) between time t1 and time t0, it being understood that what is described here can apply analogously to any other notation of the time period 220. The diagram 300 shows the rate, R B with which the sensor 112 is coated.

[0103] In some embodiments, time t0 may essentially be the time at which the control device 118 actuates the drive device 116 to open the shutter 114. In other embodiments, the vacuum coating arrangement 100 may include at least one first additional sensor configured to detect the beginning of the opening of the shutter 114 as time t0.

[0104] According to various embodiments, the vacuum coating arrangement 100 may comprise at least one second additional sensor. The at least one second additional sensor may be configured to detect a time t0+Δt s0 to detect the moment at which the shutter 114 is fully opened. The time difference between the beginning of the opening process and the end of the opening process is the opening time Δt s0 .

[0105] According to various embodiments, a time t1-Δt S1 The time at which the closing process begins and / or the time t1 at which the closing process ends (i.e., is completed) are recorded. The time difference between the start of the closing process and the end of the closing process is the closing time duration Δt S1 .

[0106] In the phase (from the time t0+Δt s0 until the time t1-Δt S1 ) between the opening process and the closing process, the rate, R B , at a maximum rate, R B,max , saturate. According to various aspects, the time period 220 may be selected such that the phase (from time t0+Δt s0 until the time t1-Δt S1) between the opening and closing process is at least one third of the time period 220. It is understood that the smaller the opening time period Δt S0 and the closing time Δt S1 are, the shorter the time period 220 can be (and the longer the service life of the vacuum coating arrangement 100). According to various aspects, the time measurement can be carried out with a temporal accuracy of at least 0.1%. According to various embodiments, the time period 220 (i.e., the time difference Δt between the time t1 and the time t0) can be determined from the opening time period Δt S0 and the closing time Δt S1 exist (ie Δt = Δt S0 +Δt S1 ). Consequently, the time period 220 in this case cannot have a time interval between the opening process and the closing process (ie Δt-Δt S0 -Δt S1 = 0). If Δt = Δt S0 +Δt S1, the measurement sequence can be set up as a continuous process (opening and closing).

[0107] The control device 118 can be configured to determine the indication of the actual state of the rate at which the coating material is emitted using the time dependence of the opening and closing in conjunction with the opening time duration Δt S0 and the closing time Δt S1 .

[0108] According to various embodiments, the shutter 114 and the drive device 116 can be configured such that a speed at which the shutter 114 is moved from one state (e.g., closed state or open state) to the other state (e.g., open state or closed state) is substantially constant. For example, the shutter 114 can be rotatably mounted, as explained above, and the drive device 116 can comprise the stepper motor. The substantially constant switching speed (i.e., the speed at which switching from one state to the other occurs) results in a change in the rate R B , with which the sensor 112 is coated, is essentially constant. In this case, the rate R B , with which the sensor 112 is coated, for the opening time period Δt S0 and the opening time Δt S1approximately half the maximum rate, R B,max .

[0109] According to various embodiments, the control device 118 may be configured to determine the indication of the actual state of the rate at which the coating material is emitted using the (e.g., detected) opening time Δt S0 and the (e.g. recorded) closing time Δt S1 to determine.

[0110] In some embodiments, the control device 118 can be configured to determine the information about the actual state of the rate at which the coating material is emitted using a predefined (e.g., stored) (opening and / or closing) switching time. In this case, the at least one second additional sensor is optional. In this case, the time t0 can essentially be the time at which the control device 118 controls the drive device 116 to open the shutter 114, the time t0+Δts0 can be determined based on the (e.g. saved) predefined opening time Δt S0 be determined, the time t1-Δt S1 can essentially be the time at which the control device 118 controls the drive device 116 to close the shutter 114, and the time t1 can be determined based on the (e.g. stored) predefined closing time period Δt S1 As an alternative to the predefined (e.g., stored) (opening and / or closing) switching time, the control device 118 can be configured to determine the switching time based on a predefined (e.g., stored) switching speed.

[0111] This comparison of the measurement method described here with the measurement method according to the state of the art clearly shows that the coating time (i.e. the time during which the sensor (e.g. the quartz crystal) is coated) can be significantly reduced compared to the state of the art (since no waiting for thermal equilibrium is required). This leads to a service life of the vacuum coating arrangement that is increased by several dimensions.

[0112] Examples of the information explained herein, which represents an actual state of a rate (also referred to as emission rate) at which a coating material is emitted, include: - a (e.g. time-averaged) mass flow of the coating material, - a rate at which the sensor is coated with the coating material, - an amount of coating material with which the sensor is coated within the period of time; - a frequency of the sensor, e.g. of the quartz oscillator; - a time until the sensor is coated with a desired amount of coating material.

[0113] It can be understood that what is described herein for the emission rate detected by the sensor can apply by analogy to any other operating parameter (e.g. of a process, e.g. coating process) detected by a sensor whose output and / or operation is dependent, for example, on a disturbance which is, for example, a function of time and / or the temperature of the sensor.

Claims

[1] Method comprising: • Determining an indication that represents an actual state of a rate at which a coating material is emitted based on: ◯ a first response of a sensor (112) before the sensor (112) is exposed to the coating material and is preferably heated thereby, and ◯ a second response of the sensor (112) after the sensor (112) has been exposed to the coating material and preferably cools down; and • Controlling an actuator configured to influence the rate based on the indication. [2] The method of claim 1, wherein determining the indication is further based on a period of time (220) for which the sensor (112) is exposed to the coating material. [3] Method according to claim 1 or 2, wherein the first response of the sensor (112) occurs before the sensor (112) is heated; and / or wherein the second response of the sensor (112) occurs when the sensor (112) cools down or after the sensor (112) has cooled down. [4] The method of any one of claims 1 to 3, wherein the sensor (112) is not exposed to the coating material during the first response and / or the second response. [5] The method of any one of claims 1 to 4, wherein the first response and / or the second response of the sensor (112) are a function of a temperature of the sensor (112). [6] Method according to one of claims 1 to 5, wherein a period of time (220) for which the sensor (112) is exposed to the coating material: • is less than or equal to 60 seconds, preferably less than or equal to 10 seconds, further preferably less than or equal to 500 milliseconds; • ends before the sensor (112) exposed to the coating material has reached thermal equilibrium. [7] Method according to one of claims 1 to 6, wherein the sensor (112) comprises a quartz crystal which is exposed to the coating material. [8] Method according to one of claims 1 to 7, further comprising: • Controlling an actuator configured to influence a period of time (220) for which the sensor (112) is exposed to the coating material and / or an amount of the coating material to which the sensor (112) is exposed between the first response and the second response. [9] Method according to claim 8, wherein the indication is further determined based on an additional indication about at least one section (Δt S0 , Δt S1 ) the time period (220) for which a mass flow of the coating material to which the sensor (112) is exposed is time-dependent. [10] Method according to claim 9, wherein the at least one section (Δt S0 , Δt S1) a switching time of a shutter (114) or is at least a function thereof; and / or wherein the mass flow is a function of a position of the shutter (114) relative to the sensor (112). [11] Method according to one of claims 1 to 10, wherein, in determining the indication, a time dependence of a mass flow of the coating material to which the sensor (112) is exposed is further taken into account; wherein the time dependence is preferably taken into account as the mean value of the time dependence of the mass flow. [12] Method comprising: • Determine an indication that represents the current state of a process based on: ◯ a first response of a sensor (112) before the sensor (112) is exposed to the process and is preferably heated thereby, and ◯ a second response of the sensor (112) after the sensor (112) has been exposed to the process and preferably cools down; and • Controlling an actuator that is configured to influence the process based on the information. [13] A computer program arranged, when executed by a processor, to cause the processor to perform the method according to any one of claims 1 to 12. [14] A computer-readable medium storing instructions arranged, when executed by a processor, to cause the processor to perform the method according to any one of claims 1 to 12. [15] Control device (118) comprising one or more than one processor configured to perform the method according to any one of claims 1 to 12. [16] Vacuum coating arrangement (100), comprising: • the control device (118) according to claim 15; • a coating device (104) for emitting the coating material; • the actuator for controlling the coating device (104); and • the sensor (112).

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