DE102021112648A1 - Sensor device and method for determining a kinematic variable of a relative movement - Google Patents

Abstract

An optoelectronic transmitter device (10) is specified for determining a kinematic variable of a relative movement of a first object to a second object, the transmitter device (10) having a material measure (14) which can be connected to the first object and having at least one code track (16), a scanning unit that can be connected to the second object, with a light transmitter (20) for illuminating or transilluminating the scale (14) with transmitted light (30) in the area of the code track (16), so that a light pattern is created, and with a light receiver (24) for generating a received signal from the light pattern incident on the light receiver (24) and a control and evaluation unit (28) which is designed to determine the kinematic variable from the received signal. The scanning unit has an adaptive lens (22).

Description

The invention relates to an encoder device and a method for determining a kinematic variable of a relative movement according to the preamble of claim 1 and 14, respectively.

In the case of encoder devices, a distinction is made between linear and rotary systems. A linear encoder determines a displacement on an axis. A rotary encoder, rotary angle sensor or encoder, on the other hand, serves to detect a rotary angle or an angular position, for example of a shaft of a drive element. An important field of application are so-called motor feedback systems, where the rotary encoder in a servo motor reports the actual speed to the controller.

In each case, a material measure is scanned, which is attached along the linear axis or on the shaft so that it rotates. In the case of an optical measuring principle and in particular a projection principle, a modulator is irradiated or penetrated by a light transmitter with a material measure, and this intensity-modulated light is detected by a light receiver. The modulator is, for example, a rotating code disk which, as a material measure, has optically transparent and non-transparent areas for transmitted light or reflective and absorbing areas for incident light. The areas or code elements can be openings, reflective and diffractive structures, prisms, structures that vary in transmission, reflectivity, shade of gray or color and other optically distinguishable elements. Together, the code elements result in a measuring track, and thus an illumination pattern and, with the rotation, a local modulation of the light impinging on the light receiver is generated. The principle can be transferred to a material measure for length measurement, which then of course does not rotate, but performs a relative movement in the longitudinal direction.

The corresponding modulated received signal from the light receiver is evaluated in order to obtain the position information sought. Incremental sine/cosine encoders, which generate a sine and a cosine signal with two receiving elements with a mutual phase offset of 90°, are particularly widespread. However, there are also incremental systems with more receiving elements, for example to obtain differential signals with additional negative sine and cosine signals, with other phase differences such as 120° or other non-sinusoidal modulations. Furthermore, absolute transmitter devices are known which use different forms of unambiguous coding to detect absolute positions and not just displacements or changes. There is often more than one scanned gauge, such as an absolute gauge and an incremental gauge.

The light from the light transmitter for illuminating or transilluminating the modulator is usually adapted by a lens to the requirements of the arrangement of scale and detection and is collimated or parallelized for this purpose. This beam shaping ensures the function and the best possible signal quality. However, narrow mechanical tolerances must be maintained for this beam shaping. However, it is structurally very difficult to maintain tolerances in the range of less than 10 μm on the transmission side, so that in practice there is a scattering in the production of the lighting unit. If the distance between the light transmitter and the lens is not optimal, the collimation will not be ideal, in other words an undesired divergent or convergent beam path after the lens. As a result, the contrast of the signals decreases, and the already very narrow and sensitive distance tolerance between the scale and the detector on the receiving side, which is also in the range of less than 10 µm, is further reduced. The homogeneity of the illumination intensity across the illuminated area also decreases, which has an additional negative effect on the signal quality.

Focus adjustments are known from technical areas outside of transmitter devices, with which the back focus is typically adjusted, i.e. the distance between the light receiver and the lens or between the light emitter and the lens. However, this is far too complex and too large for a rotary encoder. Also known are lenses in which the shape and thus the focal length of the lens itself is directly varied by means of a voltage control. This too has hitherto not been used in generic transmitter devices.

Examples of a variable focal length lens are gel or liquid lenses. In a gel lens, a silicone-like liquid is mechanically deformed using piezoelectric or inductive actuators. Liquid lenses, for example, exploit the so-called electrowetting effect (electrowetting) by arranging two immiscible liquids one on top of the other in a chamber. When a control voltage is applied, the two liquids change their surface tension in different ways, so that the inner interface of the liquids changes its curvature depending on the voltage.

In a further development of such liquid lenses for focus adjustment proposes EP 2 071 367 A1 before, also the tilting of the liquid lens by putting it on to change different tensions in the direction of rotation. To prevent blurry images from being captured, the camera's own motion is then detected and one or more lenses in the camera are tilted to counteract this self-motion. Image stabilization is not relevant for a rotary encoder, would not be transferrable and would not solve the problem of an impaired signal quality due to tolerances.

In the DE 10 2005 015 500 A1 Another optoelectronic sensor with a liquid lens is disclosed, the beam shaping properties of which can be changed asymmetrically by means of an asymmetrical frame or different electrical potentials at separate electrodes of the lens frame. However, the document does not explain what this can be used for.

the DE 10 2005 040 772 B4 deals with optical length measurement using a liquid lens. However, this form of length measurement has nothing to do with a generic encoder device, because no material measure is scanned. Rather, as in an optical mouse, a movement is detected from a scene using spatial frequency methods or optical flow. In addition, the liquid lens is not located in the illumination, but in a lens of the image recording, and in this position it cannot fundamentally contribute to a signal improvement in the case of construction-related tolerances in the illumination unit of a transmitter device. It is therefore the object of the invention to improve the determination of a kinematic quantity using a transmitter device.

This object is achieved by a transmitter device and a method for determining a kinematic variable of a relative movement of a first object to a second object according to claims 1 and 14, respectively. The two objects are movable relative to each other in a longitudinal or rotational direction and the corresponding position or angularity is to be measured. A measuring standard with at least one elongated or circular measuring track or code track can be connected to the first object and a scanning unit for scanning the measuring standard can be connected to the second object. When installed in the application, the relative movement of the objects is transferred to a relative movement between the scale and the scanning unit. First object and second object are interchangeable terms. In the case of a linear movement, the encoder device is also referred to as a linear encoder, in the case of a rotary movement as a rotary encoder, angle of rotation sensor or encoder, when used in a servo motor in particular as a motor feedback system, and the first object is then preferably a shaft and the second object is a stationary part or encoder housing. Variables derived from the position or angular position can be generated, such as a speed or angular velocity.

In the scanning unit, a light transmitter generates light that illuminates or shines through the scale in the area of the code track. The resulting light pattern differs depending on the relative position of the scale, which consequently acts as a modulator with its code track, as described in the introduction. The light pattern falls on a light receiver and generates a corresponding received signal there. The light receiver preferably has a number of light receiving elements and consequently generates a number of received signals. A control and evaluation unit evaluates the received signal or signals in order to determine the sought-after kinematic variable of the relative movement. This can be the incremental and/or absolute position or a variable derived from it, for example a speed or acceleration that is determined by derivation.

The invention is based on the basic idea of using an adaptive lens in the transmitter device. An adaptive lens can be changed in terms of its focal length and/or orientation. The beam path of the transmitted light or the light pattern in the transmitter device can be adjusted with the aid of the adaptive lens.

The invention has the advantage that an optimal lighting situation can be created. This improves the signal-to-noise ratio and ultimately the robustness and accuracy of the kinematic quantity measurement. In contrast to a rigid lens, tolerances in production can be compensated for in a very simple manner via the adaptive lens, so that the manufacture of the transmitter device is simplified and costs are reduced. The optimized beam shaping by means of the adaptive lens can relate to the beam cross section, and at the same time it preferably ensures that the light is distributed as homogeneously as possible over the illuminated area.

The light transmitter is preferably arranged on one side of the scale and the light receiver on the other side of the scale. The scanning thus takes place in transmission or projection. In this context, an adapted beam shaping is particularly important. An alternative scanning in reflection with light emitter and light receiver on the same side of the scale is possible.

The code elements of the code track are preferably in the form of code slots or code reflectors. This corresponds to a transmissive or reflective scanning in transmitted or reflected light. The code elements preferably form an absolute coding or an incremental coding. The invention can therefore be used for both types of coding.

The adaptive lens is preferably arranged between the light transmitter and the material measure. The beam shaping of the transmitted light therefore takes place before the transmitted light falls on the code track.

The adaptive lens is preferably a liquid lens or a gel lens. Such lenses are available as a component, they offer the desired setting options and are very small and inexpensive.

The adaptive lens is preferably adjusted in such a way that the transmitted light is collimated. A particularly advantageous beam formation and a particularly good signal are thus generated, and collimated light allows a distance tolerance at the receiving end. With a conventional rigid lens, the goal is often also collimation. In reality, however, this is only achieved if the components are assembled under very tight tolerance specifications. This is at least expensive and, depending on the requirements, not fully achievable. The adaptive lens according to the invention, on the other hand, enables collimation while still compensating for the actual tolerances in the installed state.

The adaptive lens is preferably set in such a way that the transmitted light is bundled or scattered. This deliberately deviates from collimation and does not necessarily lead to better beam shaping. An additional adjustment tolerance can possibly be compensated for by stretching or compressing the light pattern without impairing the signal quality excessively. For a scattered transmitted light bundle, the adaptive lens does not necessarily have to be able to assume a negative focal length; on the contrary, the situation can arise in which an original divergence of the light transmitter is only partially compensated by the adaptive lens in a targeted manner.

The adaptive lens is preferably designed to be tiltable, so that the emission direction of the transmitted light can be changed by controlling the adaptive lens. The control and evaluation unit can control the adaptive lens accordingly and thus adjust the direction of the transmitted light. This is another way of compensating for adjustment tolerances. The tilting does not, or at least not necessarily, refer to a geometric tilting, but to the optical effect that effectively corresponds to a tilting. The effect is a shifting of the light pattern along the code track or transversely to it, i.e. shifting in the circumferential direction and/or radially in the case of a rotary encoder, and shifting in the longitudinal direction or transversely in the case of a length measurement.

The adaptive lens preferably has control elements that are segmented in the circumferential direction. The control elements are, for example, segmented electrodes that control a liquid lens via the electrowetting effect. Segmented actuators are also conceivable, in particular piezo actuators, which locally change the pressure on a liquid and thereby curve a membrane differently on the liquid, or which directly deform a gel-like substance of the lens. The segmentation in the circumferential direction enables a non-rotationally symmetrical influencing of the lens, which leads to the optical tilting.

The control and evaluation unit is preferably designed for a calibration mode in which a focal length and/or an orientation of the adaptive lens is changed. The calibration in the calibration mode can already be carried out at the factory, for example in the final production, alternatively during commissioning, during maintenance or also during operation, preferably in a temporary standstill phase. The aim of the calibration is to find and set an optimal position of the adaptive lens for optimal beam shaping and thus to compensate for initial tolerances or tolerances that may have arisen during operation. The calibration preferably takes place in several relative positions of the material measure and the scanning unit.

The control and evaluation unit is preferably designed to determine a level of the received signal and in particular to optimize it using the adaptive lens. The typical optimization goal is a maximum level, all other things being equal, that promises the best signal-to-noise ratio. The current setting of the adaptive lens can be evaluated via the received signal, in particular its level. In particular, by evaluating the level, an automatic calibration is possible, which runs through various settings of the adaptive lens and finally selects the setting that maximizes the level. This can even be extended to a rule.

The control and evaluation unit is preferably designed to vary the focal length and/or alignment of the adaptive lens for a self-check, to evaluate the respective received signal and, if necessary, to carry out a maintenance or to issue an advance notification. This can be classified under the term condition monitoring. The purpose of this is to check the status of the transmitter device in order to be able to issue a maintenance or pre-failure message in good time if necessary. For example, the code disk distance can be remeasured by varying the focal length during operation or during a break in operation.

The control and evaluation unit is preferably designed to compare the respective received signal with a previously stored reference signal that was detected in a target state of the transmitter device, in particular a received level and a reference level with the same activation of the adaptive lens in each case. Accordingly, the transmitter device comprises a memory, in particular a memory of the control and evaluation unit, in which an expectation of an intact transmitter device is stored in the form of at least one reference signal. In this case, several reference signals can be stored for different positions of the adaptive lens. Under otherwise comparable boundary conditions, in particular with regard to the relative movement, the respective received signal should match this expectation. Otherwise an error in the encoder device is assumed and a corresponding message is output. The comparison preferably takes place at the level or amplitude level, accordingly reference levels are then stored instead of entire time-dependent reference signals.

The light receiver preferably has at least one test light receiving element in order to check the beam formation of the transmitted light. In this embodiment, there is at least one dedicated test light receiving element or at least one photodiode, which is only used to check the setting of the adaptive lens. This has the advantage that the arrangement, connection, type and evaluation of the test light receiving element are tailored to this task and there are no interactions with the actual measurement task. Alternatively, at least one existing light receiving element of the light receiver is used in a dual function to check the setting of the adaptive lens.

The encoder device is preferably designed as a rotary encoder. In a rotary encoder, the relative movement of the scale, which is then also referred to as a code disk, is a rotation or turn, and the code elements are arranged on a circle for each track. In an alternative length measuring system, the scale is elongated, with the code elements of a track being arranged on a straight line. The use of an adaptive lens according to the invention is advantageous in both cases.

The method according to the invention can be developed in a similar way and shows similar advantages. Such advantageous features are described by way of example but not exhaustively in the dependent claims which follow the independent claims.

• 1 eine schematische Darstellung eines Drehgebers;
• 2a eine Darstellung des Strahlverlaufs von kollimiertem Sendelicht an einer adaptiven Linse in einer Gebervorrichtung in einem Sollabstand von Lichtsender und Maßverkörperung;
• 2b eine Darstellung ähnlich 2a, jedoch mit zu kurzem Abstand zwischen Lichtsender und Maßverkörperung und Kompensation durch kleinere Brennweite der adaptiven Linse;
• 2c eine Darstellung ähnlich 2a, jedoch mit zu großem Abstand zwischen Lichtsender und Maßverkörperung und Kompensation durch größere Brennweite der adaptiven Linse;
• 3a eine Darstellung des Strahlverlaufs von kollimiertem Sendelicht an einer adaptiven Linse in einer Gebervorrichtung in einer Sollanordnung von Lichtsender und Maßverkörperung;
• 3b eine Darstellung ähnlich 3a, jedoch mit Strahlaufweitung durch kleinere Brennweite der adaptiven Linse;
• 3c eine Darstellung ähnlich 3a, jedoch mit Strahlbündelung durch größere Brennweite der adaptiven Linse
• 4a eine Darstellung einer adaptiven Linse in einer strahlaufweitenden Einstellung;
• 4b eine Darstellung der adaptiven Linse in einer neutralen Einstellung;
• 4c eine Darstellung der adaptiven Linse in einer strahlbündelnden Einstellung;
• 5a eine Darstellung der adaptiven Linse mit Verkippen nach unten;
• 5b eine Darstellung der adaptiven Linse ohne Verkippen; und
• 5c eine Darstellung der adaptiven Linse mit Verkippen nach oben.

The invention is explained in more detail below, also with regard to further features and advantages, by way of example on the basis of embodiments and with reference to the attached drawing. The illustrations of the drawing show in:

• 1 a schematic representation of a rotary encoder;
• 2a a representation of the beam path of collimated transmitted light on an adaptive lens in a transmitter device at a desired distance from the light transmitter and scale;
• 2 B a representation similar 2a , but with too short a distance between the light emitter and the material measure and compensation through the smaller focal length of the adaptive lens;
• 2c a representation similar 2a , but with too great a distance between the light emitter and the material measure and compensation through a larger focal length of the adaptive lens;
• 3a a representation of the beam path of collimated transmitted light on an adaptive lens in a transmitter device in a target arrangement of light transmitter and material measure;
• 3b a representation similar 3a , but with beam expansion due to the smaller focal length of the adaptive lens;
• 3c a representation similar 3a , but with beam bundling due to the larger focal length of the adaptive lens
• 4a an illustration of an adaptive lens in a beam-expanding setting;
• 4b a representation of the adaptive lens in a neutral setting;
• 4c a representation of the adaptive lens in a beam-forming setting;
• 5a an illustration of the adaptive lens with tilt down;
• 5b a representation of the adaptive lens without tilting; and
• 5c an illustration of the adaptive lens with tilt up.

1 shows a schematic representation of a transmitter device 10, which is designed as a rotary transmitter or encoder, for example, for a motor feedback system. The encoder device 10 has a code disk rotating with the shaft 12 as a measuring standard 14, and a code track 16 with a large number of code elements 18 is located on the measuring standard 14. The code track 16 can be an incremental code track or a more complex code track, for example for absolute positioning. In addition, contrary to the simplified representation, multiple code tracks can be provided.

A light transmitter 20 on the circumference of the scale 14, for example an LED, radiates transmitted light onto the scale 14 through a transmission optics with an adaptive lens 22. The focal length and/or tilting direction of the adaptive lens 22 can be changed, this function will be explained later with reference to further figures explained in more detail. In other specific embodiments, the transmission optics has further optical elements in addition to the adaptive lens 22, such as at least one additional concave or convex lens, at least one deflection element or a diaphragm.

The transmitted light beam-shaped in this way is modulated by the code elements 18 . For this purpose, the code elements 18 are designed as code slots or, more generally, as transparent areas. Thus arises in 1 below the scale 14 a light pattern of light-dark transitions depending on the rotational position of the scale 14. The light pattern falls on a light receiver 24 with one or more light receiving elements 26 preferably in a row. The light receiver 24 is designed, for example, as an opto-ASIC (Application-Specific Integrated Circuit) or with discrete photodiodes.

In the course of the rotational movement of the measuring standard 14, modulated received signals are thus produced, which are evaluated by a control and evaluation unit 28 in order to determine the angular position of the measuring standard 14 and, depending on the embodiment, other kinematic variables. Depending on the material measure 14 and the code track 16, various measurements are conceivable, in particular an incremental and/or absolute position determination. Deviating from 1 several code tracks 16 can also be combined into one measurement or for several measurements, for example in order to carry out both an incremental and an absolute position determination.

The representation of the transmitter device 10 in 1 is very schematic. Therefore, the design of the scanning unit with light transmitter 20, adaptive lens 22 and light receiver 24 in 1 kept very simple. In particular, with regard to the dimensions and specific positions of the components, the encoder device 10 can in practice greatly 1 differ. As an alternative to a transmissive structure, a reflective structure is also conceivable, in which the light transmitter 20, adaptive lens 22 and light receiver 24 are on the same side of the scale 14 and the code elements 18 have reflective properties.

The encoder device 10 can also be designed as a linear encoder or longitudinal measuring system instead of as a rotary encoder. The scale 14 is then not circular, but elongated, the measuring track is accordingly arranged on a straight line instead of a circle, and instead of a rotation, the movement takes place in the longitudinal direction.

2a shows the beam path of the transmitted light 30 generated by the light transmitter 20. In this embodiment, the aim is collimated, ie parallelized, transmitted light 30 as shown. However, based on an initially fixed focal length setting of the adaptive lens 22, this presupposes close compliance with tolerance specifications for the arrangement and alignment of the components with respect to one another, typically in the order of only a few tens of micrometers.

With the adaptive lens 22, which is a liquid or gel lens, for example, and which can alternatively be constructed using any other technology known per se, collimated transmitted light 30 can also be achieved for deviating relative arrangements that vary by more than the tolerance specifications. The focal length of the adaptive lens 22 can be changed by the control and evaluation unit 28 by appropriate control, for example by applying a control voltage. With a suitable focal length, the beam formation of the transmitted light 30 can be optimally adjusted to the requirements of the system. For this reason, the collimation in particular can also be correctly set or corrected later, even after the system has been assembled with tolerances. In this way, the assembly tolerances discussed increase considerably. With the adaptive lens 22, the 2a should also be understood in such a way that the appropriate focal length for the given constellation was found and set here, instead of imagining the focal length as fixed, as initially assumed.

2 B shows for comparison in a representation analogous to 2a the beam path of the transmitted light 30 generated by the light transmitter 20 in a transmitter device 10, in which, because of the tolerances after the construction of the distance between the light transmitter 20 and scale 14, respectively code track 16 became too small. By setting a larger focal length of the adaptive lens 22, this can be compensated for and still collimated transmitted light 30 can be generated.

2c shows the opposite situation, in which the distance between the light transmitter 20 and the material measure 14 or the code track 16 became too large because of the tolerances after the construction. This is now compensated for by a smaller focal length of the adaptive lens 22 in order to nonetheless generate collimated transmitted light 30 .

The collimation achieved in each case, or, with reference to further embodiments to be presented more generally, the beam shaping achieved, can be checked with at least one special photodiode of the light receiver 24, which is not specifically shown, and in this way an automatism or even a type of control can be implemented in order to achieve a desired beam shape of the To achieve transmission light 30. As an alternative to a dedicated special photodiode, at least one light receiving element 26 of the light receiver 24 can be used for this purpose. For example, to calibrate, i.e., adjust the adaptive lens 22 appropriately, a level is maximized. The beam shaping of the transmitted light 30 can be adjusted once during production, during commissioning, during maintenance or continuously or cyclically during operation.

the 3a-c illustrate an alternative embodiment in which the transmitted light 30 is not collimated but instead is focused or scattered. 3a is once again the same representation as that 2a and is for comparison only. In 3b the transmitted light 30 after the adaptive lens 22 has a divergence, in 3c a convergence. It should be noted that a negative focal length is not required for a divergence, which in turn is not ruled out because it is sufficient if the original divergence of the transmitted light at the light transmitter 20 is not completely compensated for. The intentional deviation from collimation serves, for example, to compensate for an incorrect position or arrangement of the light receiver 24 by the projection of the material measure 14 or the light pattern being correspondingly stretched or compressed. Alternatively, a misalignment in the direction of the code track 16 or transversely thereto can be compensated for by the adaptive lens 22 being tilted in its viewing direction. Such an adaptive lens is finally described with reference to FIG 5a-c presented.

the 4a-c and 5a-c 12 show an exemplary embodiment of the adaptive lens 22 as a liquid lens according to the electrowetting effect. The mode of operation is explained in more detail using such a liquid lens as an example, but the invention also includes other adaptive lenses, for example those with a liquid chamber and a membrane covering it, the curvature of which is changed by pressure on the liquid, lenses with a gel-like optically permeable material that is mechanically deformed by an actuator or lenses with other deformable surfaces.

In this embodiment, as a liquid lens, the adaptive lens 22 has two transparent, immiscible liquids 32, 34 with different refractive indices and the same density. The shape of the liquid-liquid interface 36 between the two liquids 32, 34 is used for the optical function. The actuation is based on the principle of electrowetting, which shows a dependence of the surface or interfacial tension on the applied electric field. It is therefore possible to change the shape of the boundary layer 36 and thus the optical properties of the adaptive lens 22 by electrical control at a connection 38, as a result of which corresponding voltages are applied to an electrode 40.

the 4a-c first shows the change in the focal length of the adaptive lens 22. In 4a incident transmission light 30 is scattered at a concave boundary layer 36 . 4b shows a neutral setting with a flat boundary layer 36, while in 4c the boundary layer is convex and thus bundles the incident transmitted light 30 . It is clear that the refraction behavior can be graded more finely by appropriate intermediate settings and a desired focal length can thus be set. In the 4a-c parallel light is already incident, while the transmitted light 30 is typically initially divergent. This does not imply any restriction with which 4a-c different focal lengths of the adaptive lens 22 are illustrated only by way of example.

The tilting of the adaptive lens 22 can preferably be influenced. This will be in the 5a-c illustrated and is based on non-rotationally symmetrical applied voltages and thus electric fields. Accordingly, the boundary layer 36 is not deformed rotationally symmetrically, which is used for the tilting. 5a shows a tilting of the adaptive lens 22 downwards, 5b a rotationally symmetrical setting without tilting for comparison, and 5c a tilting of the adaptive lens 22 upwards. In this case, the direction of tilting relates in each case to the optical effect, ie from which transmitted light 30 is received or in which direction transmitted light is emitted. A focal length setting can be superimposed on the tilting.

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 2071367 A1 [0008]
• DE 102005015500 A1 [0009]
• DE 102005040772 B4 [0010]

Claims (14)

Optoelectronic encoder device (10) for determining a kinematic variable of a relative movement of a first object to a second object, wherein the encoder device (10) has a material measure (14) that can be connected to the first object and has at least one code track (16), a code track that can be connected to the second object Scanning unit with a light transmitter (20) for illuminating or transilluminating the scale (14) with transmitted light (30) in the area of the code track (16), so that a light pattern is created, and with a light receiver (24) for generating a received signal from the Light receiver (24) has incident light patterns and a control and evaluation unit (28) which is designed to determine the kinematic variable from the received signal, characterized in that the scanning unit has an adaptive lens (22). Transmitter device (10) after claim 1 , wherein the light transmitter (20) is arranged on one side of the measuring standard (14) and the light receiver (24) on the other side of the measuring standard (14). Transmitter device (10) after claim 1 or 2 , The adaptive lens (22) being arranged between the light transmitter (20) and the material measure (14). A transducer device (10) as claimed in any preceding claim, wherein the adaptive lens (22) is a liquid lens or a gel lens. Transmitter device (10) according to one of the preceding claims, wherein the adaptive lens (22) is adjusted in such a way that the transmitted light (30) is collimated. Transmitter device (10) according to one of Claims 1 until 4 , wherein the adaptive lens (22) is set so that the transmitted light (22) is bundled or scattered. Transmitter device (10) according to one of the preceding claims, wherein the adaptive lens (22) is designed to be tiltable, so that the emission direction of the transmitted light (30) can be changed by controlling the adaptive lens (22). Transmitter device (10) according to one of the preceding claims, wherein the control and evaluation unit (28) is designed for a calibration mode in which a focal length and/or an alignment of the adaptive lens (22) is changed. Transmitter device (10) according to one of the preceding claims, wherein the control and evaluation unit (28) is designed to determine a level of the received signal and in particular to optimize it by means of the adaptive lens (22). Transmitter device (10) according to one of the preceding claims, wherein the control and evaluation unit (28) is designed to vary the focal length and/or alignment of the adaptive lens (22) for a self-check, to evaluate the respective received signal and, if necessary, to carry out a maintenance or to issue an advance notification. Transmitter device (10) according to one of the preceding claims, wherein the control and evaluation unit (28) is designed to compare the respective received signal with a previously stored reference signal that was detected in a target state of the transmitter device (10), in particular a received level and a reference level with the same control of the adaptive lens (22). Transmitter device (10) according to one of the preceding claims, wherein the light receiver (24) has at least one test light receiving element in order to check the beam formation of the transmitted light (30). Encoder device (10) according to one of the preceding claims, wherein the encoder device (10) is designed as a rotary encoder. Method for determining a kinematic variable of a relative movement of a first object to a second object, with the first object having a material measure (14) with at least one code track (16) and the second object being a scanning unit with a light transmitter (20) for illuminating or transillumination the scale (14) with transmitted light (30) in the area of the code track (16), so that a light pattern is created, and is connected to a light receiver (24) for generating a received signal from the light pattern falling on the light receiver (24) and the kinematic Size is determined from the received signal, characterized in that a beam shaping of the transmitted light (30) takes place with an adaptive lens (22).

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