DE102017205105B4 - Probing element, light indicator, coordinate measuring machine and method for determining a position of a reference surface in relation to a mechanical reference - Google Patents

Abstract

Contact element (110) for measuring at least one measurement object (112) comprising
- At least one tactile sensor (114), the tactile sensor (114) having at least one tactile probe element (116) which is set up to tactilely scan a surface of the measurement object (112);
- At least one optical system (118), the optical system (118) being set up to generate at least one optical signal (120); wherein the contact element (110) is set up to apply the optical signal (120) to the measurement object (112) through the tactile feeler element (116), the optical system (118) having at least one imaging device (152) which is set up to at least partially image the measurement object (112), and / or wherein the optical system (118) has at least one confocal sensor (154) which is set up to measure the measurement object (112) without contact, and / or wherein the optical system ( 118) has at least one autocollimation telescope (156) which is set up to measure the angle of the measurement object (112).

Description

Field of invention

The invention relates to a contact element, a light indicator, a coordinate measuring device and a method for determining a position of a reference surface relative to a mechanical reference. The present invention relates in particular to the field of coordinate measuring technology using a tactile coordinate measuring machine.

State of the art

Various devices and methods for measuring objects to be measured are known from the prior art. For example, coordinate measuring machines with tactile sensors are used which touch a surface of the measurement object, for example mechanically. Such tactile sensors typically have a probe element in the form of a probe ball, which is attached to a transmission element. When the probe ball is touched with the measuring object, the forces that arise on the probe ball are measured in three axes and a directional vector of the probe, the so-called probe vector, is determined from this and the measuring object is measured. Devices which have optical sensors are also known, in particular coordinate measuring devices with an optical measuring head or measuring microscopes. Such devices are set up to measure the measurement object without contact.

However, such known devices are disadvantageous when determining a position, in particular a material measure, of a reference surface, for example a CCD chip, in space. For example, a measuring microscope can determine a position of a pixel within a coordinate system of the reference surface by fading in a crosshair and reading it out using a camera. However, the determination of the position of a mechanical reference can be problematic, since the measuring microscope can only imprecisely determine edges, in particular in the case of rough edges and in the case of edges with a bevel or rounding. In addition, an edge can only describe the associated surface imprecisely because, for example, a surface tilt is not recorded. For example, a mechanical reference can be probed with an optical measuring head, but a clear localization of pixels of a CCD chip can be problematic. For example, it may not be possible to optically unambiguously determine a first active pixel on the CCD chip, since the pixel must also be illuminated or shaded and the CCD chip must be read out in order to obtain an assignment of a pixel index to the spatial coordinate. Targeted pixel lighting is not possible with an optical measuring head.

U.S. 5,118,956 A describes a touch trigger probe, which is provided with a sensor that changes its state by vibration or stress when a pen is connected. The probe touches a workpiece. The sensor is typically provided on or in the pen. The change in state of the sensor causes a change in the path length, the polarization state or the intensity of the light waves transmitted by the sensor. An interferometer can be provided to detect such changes.

U.S. 4,792,698 A describes a device and a method for detecting the presence or the position of an object in a plane perpendicular to a reference axis. An optical detector that uses triangulation techniques is used to detect the presence or approximate location of the object. A contact detector is then used to determine the exact location of the object.

Object of the invention

It is therefore the object of the present invention to provide a contact element, a light indicator, a coordinate measuring device and a method for determining a position of a reference surface relative to a mechanical reference, which at least largely avoid the disadvantages of known devices and methods. In particular, a determination of a position of a reference surface in space should be made possible.

Disclosure of the invention

This object is achieved by a probe element, a light indicator, a coordinate measuring device and a method for determining a position of a reference surface relative to a mechanical reference with the features of the independent claims. Advantageous developments, which can be implemented individually or in combination, are presented in the dependent claims.

In the following, the terms “have”, “have”, “comprise” or “include” or any grammatical deviations therefrom are used in a non-exclusive manner. Accordingly, these terms can relate to situations in which, besides the feature introduced by these terms, no further features are present, or to situations in which one or more further features are present. For example, the expression “A has B”, “A has B”, “A includes B” or “A includes B” can refer to the situation in which, apart from B, there is no further element in A (ie a situation in which A consists exclusively of B), as well as the situation in which, in addition to B, one or more further elements are present in A, for example Element C, Elements C and D or even more elements.

Furthermore, it should be noted that the terms “at least one” and “one or more” as well as grammatical modifications of these terms or similar terms, if these are used in connection with one or more elements or features and are intended to express that the element or feature simply or can be provided several times, generally only used once, for example when the feature or element is introduced for the first time. If the feature or element is subsequently mentioned again, the corresponding term “at least one” or “one or more” is generally no longer used, without restricting the possibility that the feature or element can be provided once or several times.

Furthermore, the terms “preferably”, “in particular”, “for example” or similar terms are used below in connection with optional features, without this limiting alternative embodiments. Features introduced by these terms are optional features, and it is not intended to use these features to restrict the scope of protection of the claims and in particular of the independent claims. Thus, as the person skilled in the art will recognize, the invention can also be carried out using other configurations. In a similar way, features introduced by “in an embodiment of the invention” or by “in an exemplary embodiment of the invention” are understood as optional features without any intention that this should limit alternative configurations or the scope of protection of the independent claims. Furthermore, by means of these introductory expressions, all possibilities of combining the features introduced thereby with other features, be it optional or non-optional features, remain untouched.

In a first aspect of the present invention, a contact element for measuring at least one measurement object is proposed. In the context of the present invention, a contact element can be understood to mean a device which is basically of any shape and is set up to contact a measurement object with at least one contact and / or contact-free. In the context of the present invention, a measurement object can generally be understood to mean an object to be measured of any shape. For example, the measurement object can be selected from the group consisting of a test object, a workpiece to be measured and a component to be measured. The measurement object, in particular the surface of the measurement object, can have strong curvatures, i.e. small radii up to sharp edges. The test object can comprise a chip, in particular a microchip, with conductor track structures. However, other measurement objects are also conceivable.

• - mindestens einen taktilen Sensor, wobei der taktile Sensor mindestens ein taktiles Tastelement aufweist, welches eingerichtet ist, eine Oberfläche des Messobjekts taktil abzutasten;
• - mindestens ein optisches System, wobei das optische System eingerichtet ist, mindestens ein optisches Signal zu erzeugen;

wobei das Antastelement eingerichtet ist, das Messobjekt durch das taktile Tastelement hindurch mit dem optischen Signal zu beaufschlagen.The contact element includes

• - At least one tactile sensor, wherein the tactile sensor has at least one tactile probe element which is set up to tactilely scan a surface of the measurement object;
• - At least one optical system, wherein the optical system is set up to generate at least one optical signal;

wherein the probe element is set up to apply the optical signal to the measurement object through the tactile probe element.

In the context of the present invention, a tactile sensor can be understood to mean a sensor which is set up to interact with the surface of the measuring device, for example mechanically, and to generate information about a contact point. The tactile sensor can be designed as a button. The tactile sensor has the at least one tactile probe element. The tactile sensor can have a shaft for fastening the tactile probe element. The tactile sensor can have an adapter for connecting the tactile sensor to a further device, for example a coordinate measuring device. For example, the tactile sensor can be an optically, inductively or capacitively measuring tactile sensor.

In the context of the present invention, a touch point can be understood to mean a point, a location or an area on a surface of the sensor which has the smallest distance between the measurement object and the surface of the tactile probe element. In particular, the touch point can be a point of contact between the surface of the tactile probe element and the surface of the measurement object. The coordinate system of the probe element can be, for example, a Cartesian coordinate system or a spherical coordinate system. Other coordinate systems are also conceivable. An origin or zero point of the coordinate system can be in a center, for example a ball center point in the case of a probe ball as a tactile probe element. For example, the contact point can be a point in the coordinate system of the contact element which is arranged on the surface of the contact element.

In the context of the present invention, a “tactile probe element” can be understood as an element of the tactile sensor which is set up to interact with the surface of the measurement object. In particular, the tactile probe element can touch the measurement object at the at least one touch point. The tactile probe element can comprise a probe ball. However, other probe elements are also conceivable. “Tactile probing” and “tactile scanning” can be understood as the interaction between the tactile sensor and the measurement object. For example, the tactile probe element can touch the surface of the measurement object, for example by bringing the surface of the measurement object into contact with a surface of the tactile probe element and / or the tactile probe element can interact with the surface of the measurement object in a non-contacting manner, for example capacitively. When there is an interaction, the surface of the tactile probe element and the surface of the measurement object can touch. In particular, the surface of the tactile probe element and the surface of the measurement object can make electrical contact. Alternatively, the interaction can be non-contact, for example optical, inductive or capacitive.

The contact element can be set up to generate at least one signal, for example an electronic signal. In the context of the present invention, a signal can be understood to mean any signal that is generated by the probe element as a result of interacting with the measurement object and / or that is generated in response to interacting with the measurement object. As will be explained further below, the signal can be evaluated by at least one evaluation unit and in order to generate at least one piece of information about a measuring point on the surface of the measuring object from the signal.

“An optical system” can be understood to mean a device which has at least two optical components. The components can be designed spatially separate from one another. For example, the optical system can have a large number of optical components, for example one or more objectives, diaphragms and / or further optical components. The optical system is set up to generate at least one optical signal. The optical signal can be a light beam. In the context of the present invention, “light” can be understood to mean electromagnetic radiation in at least one spectral range selected from the visible spectral range, the ultraviolet spectral range and the infrared spectral range. The term visible spectral range basically covers a range from 380 nm to 780 nm. The term infrared (IR) spectral range basically covers a range from 780 nm to 1000 µm, with the range from 780 nm to 1.4 µm as near infrared (NIR), and the range from 15 µm to 1000 µm is called far infrared (FIR). The term ultraviolet basically comprises a spectral range from 100 nm to 380 nm. In the context of the present invention, preference is given to using visible light, that is to say light from the visible spectral range. The term “light beam” can in principle be understood to mean an amount of light that is emitted and / or sent out in a specific direction. The light beam can be a bundle of rays.

The probe element is set up to apply the optical signal to the measurement object through the tactile probe element. “To apply the optical signal through the tactile probe element” can be understood to mean that the optical signal strikes the surface of the measurement object through the tactile probe element. For example, the optical signal can be generated by the optical system in the tactile probe element or outside the tactile probe element. The tactile probe element can be set up to at least partially allow the optical signal to pass through the tactile probe element. The tactile probe element can have transmissive properties. Letting through at least partially can be understood to mean that the tactile feeler element lets the optical signal through at least 50%, preferably at least 75%, particularly preferably completely. The tactile feeler element can be at least partially transparent to the optical signal. The tactile feeler element can be made of an at least partially transparent material. For example, the at least partially transparent material can be glass, for example a borosilicate glass, for example N-Bk7, or a high-index glass, for example S-LAH79. In order to reduce wear and tear on the tactile probe element, the use of particularly scratch-resistant glass can be advantageous. Alternatively, the tactile feeler element can be made of an impermeable and / or non-transparent material, for example ruby. The optical signal can be passed through the tactile probe element. The tactile probe element can in particular have at least one bore. The tactile probe element can for example have a light guide, for example at least one optical fiber.

The optical system can be arranged at least partially in the tactile probe element. “Arranged at least partially in the tactile probe element” can be understood to mean that the optical system is arranged completely in the tactile probe element or that at least one component of the optical system is arranged outside the optical system. The optical system can be at least partially integrated in the tactile probe element. The tactile probe element can have at least one bore in which the optical system is at least partially arranged. The hole can be selected from a through hole and a blind hole. For example, the tactile probe element can be made of a material that is nontransparent for the optical signal. For example, the tactile feeler element can have a through hole. For example, the tactile feeler element can be at least partially transparent to the optical signal and can have a blind hole. The probe element can have the at least one shaft for fastening the tactile probe element. The bore can be arranged in any direction to the shaft, in particular perpendicular to the shaft or in a direction of extent of the shaft. Alternatively or additionally, the shaft can be a hollow body, for example a cylindrical hollow body, and / or can have a bore. The optical system can be arranged at least partially in the shaft. The shaft can be designed to couple the optical system into the tactile probe element.

The tactile probe element can be a terminating lens of the optical system in a direction of propagation of the optical signal from the tactile test element to the measurement object. The last optical element of the optical system can be understood as a “final lens”. As stated above, the optical signal can be a light beam. The tactile probe element can be set up to focus the light beam on the measurement object.

The shaft can have a length of less than 50 mm. A shaft length can be in the range from 20 to 240 mm. This range can also be exceeded or fallen short of for special measuring tasks. The (flexural) rigidity of the shaft is selected so that a tactile measuring force of typically 200 mN results in a deflection that is significantly smaller than 1 µm. The stiffness of the shaft can directly influence the measurement accuracy of the method.

In one embodiment, the optical system can have at least one lighting device. The lighting device can be set up to generate the optical signal, in particular at least one light beam, and to illuminate the measurement object through the tactile probe element. The lighting device can be set up to generate a light spot on the measurement object. The light spot can in principle have an area of any shape, preferably a circular area. The light spot can have a diameter of less than 10 µm on the surface of the measurement object. The lighting device can have at least one light source. The light source can be selected from at least one light-emitting diode and at least one laser diode, in particular a fiber-coupled laser diode. In particular, the light source can be set up to generate light with a wavelength of 620 nm to 700 nm. The light source can for example be a fiber-coupled laser diode with a wavelength of 635 nm. The lighting device can have at least one light guide. A “light guide” can be understood to mean an optical element which is set up to guide a light beam generated by the light source, for example by means of total reflection. The light guide can have a core and a jacket surface surrounding the core. The light guide can have at least one optical fiber selected from at least one singlemode fiber or at least one multimode fiber. The light guide can be a rigid or a flexible light guide. For example, a core diameter of a single-mode fiber can be from 3 µm to 9 µm. A numerical aperture, which is a measure of the opening angle at a fiber exit, can be approximately 0.1. For example, a core diameter of a multimode fiber can be from 50 µm to 1500 µm. The multimode fiber can be set up so that a multiplicity of modes propagate in the light guide. A numerical aperture can be about 0.2 to 0.3. The lighting device can have at least one coupling element which is set up to couple the light beam generated by the light source into the light guide, in particular into an input of the light guide. A diameter of the light spot on the surface of the measurement object can depend on the core diameter of the optical fiber. The light guide can have a core diameter that is as small as possible, so that the smallest possible diameter of the light spot is generated, in particular a diameter of the light spot smaller than 10 μm. A singlemode fiber can preferably be used. The light guide can have the smallest possible opening angle so that losses due to scattered light are prevented. The light guide can have a length of 0.1 m to 4 m, preferably a length of 1 m to 2 m.

The light guide can be at least partially integrated in the tactile probe element. For example, the light guide can be arranged in the bore of the tactile probe element. For example, a first part of the light guide can be arranged in the shaft, in particular in a bore in the shaft, and a second part of the light guide in the tactile probe element. The light guide can have an output which is set up to emit the optical signal and to apply the optical signal to the measurement object. The output can be arranged in the tactile probe element. The contact element can be set up Map the output of the fiber onto the measurement object in a size ratio of 1: 1. In the case of an arrangement with a light-emitting diode and a rigid light guide, the contact element can be set up in such a way that the output of the light guide is mapped onto the measurement object in a reduced size. A reduction by a factor of 2 to 40 is advantageous.

The optical system can have at least one lens which is set up to focus the optical signal generated by the lighting device onto the measurement object. The lens can be arranged in the bore of the tactile probe element. In particular, the lens can be a microlens. The lens can have a single lens or a lens system. The lens can have similar or identical refractive properties as the tactile probe element. In particular, the lens can be a plano-convex lens. For example, the lens can be made of barium glass, for example N-BAK2. For example, the refractive index of the lens can be from 1.5 to 1.55 for a wavelength of 635 nm.

In one embodiment, the contact element can have a feeler ball attached to the shaft. The shaft can extend essentially horizontally to a support on which the measurement object is arranged, deviations from a horizontal alignment being possible within the framework of component tolerances. For example, the probe ball can have the at least one bore, in particular a through bore, perpendicular to the direction in which the shaft extends. The output of the light guide can be arranged in the bore. Furthermore, the lens can be arranged in the bore and focus the light emitted by the light guide on the surface of the measurement object.

In one embodiment, the contact element can have a feeler ball attached to the shaft. The shaft can extend essentially perpendicular to the support on which the measurement object is arranged, with deviations from a perpendicular alignment being possible within the framework of component tolerances. For example, the probe ball can have the at least one bore in or parallel to the direction of extension of the shaft. For example, the tactile probe element can be made of a material that is nontransparent for the optical signal and the tactile probe element can have a through-hole. For example, the tactile feeler element can be at least partially transparent to the optical signal and can have a blind hole. The light guide can be arranged partly in the shaft and partly in the tactile probe element. The shaft can be designed to couple the light guide into the tactile probe element. The output of the light guide can be arranged in the bore. Furthermore, the lens can be arranged in the bore and focus the light emitted by the light guide on the surface of the measurement object. As an alternative or in addition to an embodiment with a lens for focusing the light emitted by the light guide onto the surface of the measurement object, the tactile feeler element can be at least partially transparent to the optical signal. In particular, the tactile probe element can have a glass ball. The tactile feeler element can be set up as an end lens of the optical system. The tactile feeler element can have a blind hole which has a planar or arbitrarily curved and / or structured, for example a diffraction grating, or coated base. Due to the planar base and the radius of the glass ball, the tactile feeler element can act and be set up as a plano-convex lens, or have special imaging properties due to differently curved surfaces and / or structuring and / or coating, in order to allow the light emitted by the light guide on the surface of the To focus the measurement object or to project it specifically for the application. In a further embodiment, the glass ball can be used intact as a biconvex lens or it can be converted into a plano-convex lens by flattening it on one side. In this way, the difficult process of polishing the bottom of a blind hole can be avoided. The same applies to a possible structuring or coating of the base area. In particular, the tactile probe element can have a flattened sphere. For example, a lower surface can be used as a beam splitter, in which a spherical curvature is an obstacle.

The optical system can have a plurality of optical elements selected from the group consisting of: at least one lens; at least one lens system; at least one beam splitter; at least one aperture; at least one reflector. The optical system can be set up for one or more of the following applications: illumination of the measurement object, imaging of the measurement object, non-contact measurement of the measurement object, angle measurement of the measurement object, special illumination of the measurement object using structured or specially curved optics. The optical system has at least one imaging device which is set up to at least partially image the measurement object. An “image” can basically be understood to mean generating an image of the measurement object by means of the optical system. The image can be an image of a partial area of the measurement object or an image of the entire measurement object. For example, the optical system can have a telecentric lens. The optical system has at least one confocal sensor which is set up to measure the measurement object without contact. In particular, it can optical system have at least one aperture. The optical system has at least one autocollimation telescope, which is set up to measure the angle of the measurement object.

In a further aspect, a light indicator is proposed within the scope of the present invention. The light indicator comprises a contact element. The contact element comprises at least one tactile sensor. The tactile sensor has at least one tactile probe element which is set up to tactilely scan a surface of the measurement object. The contact element comprises at least one optical system. The optical system is set up to generate at least one optical signal. The probe element is set up to apply the optical signal to the measurement object through the tactile probe element. The optical system has at least one lighting device. The lighting device is set up to generate the optical signal, in particular a light beam. The probe element is set up to apply the optical signal to the object through the tactile probe element.

A contact element according to the invention is used in the light indicator. For details with regard to the light indicator according to the invention, reference is made to the description of the device according to the invention.

• - mindestens ein erfindungsgemäßes Antastelement,
• - mindestens eine Auswerteeinheit, welche eingerichtet ist, um mindestens eine Information über einen Messpunkt an einer Oberfläche des Messobjekts zu erzeugen.

In a further aspect, a coordinate measuring device for measuring at least one measurement object is proposed within the scope of the present invention. The coordinate measuring machine includes:

• - At least one contact element according to the invention,
• - At least one evaluation unit which is set up to generate at least one piece of information about a measuring point on a surface of the measuring object.

For details and definitions with regard to the coordinate measuring machine, reference is made to the description of the probe element.

The coordinate measuring machine can be selected from a coordinate measuring machine in portal, bridge or column construction. The coordinate measuring machine can have a measuring table for supporting the measurement object. The coordinate measuring machine can have at least one portal which has at least one first vertical column, at least one second vertical column and a cross member connecting the first vertical column and the second vertical column. At least one vertical column selected from the first and second vertical columns can be movably supported on the measuring table in a horizontal direction. The coordinate measuring machine can have a coordinate system, for example a Cartesian coordinate system or a spherical coordinate system. Other coordinate systems are also conceivable. An origin or zero point of the coordinate system can be given, for example, by a sensor of the coordinate measuring machine.

The contact element can be set up to generate at least one signal, for example an electronic signal. “An evaluation unit” is generally understood to mean an electronic device which is set up to evaluate signals generated by the contact element. For example, one or more electronic connections between the contact element and the evaluation unit can be provided for this purpose. The evaluation unit can for example comprise at least one data processing device, for example at least one computer or microcontroller. The data processing device can have one or more volatile and / or non-volatile data memories, it being possible for the data processing device to be set up in terms of programming, for example, to control the contact element. The evaluation unit can furthermore comprise at least one interface, for example an electronic interface and / or a man-machine interface such as an input / output device such as a display and / or a keyboard. The evaluation unit can, for example, be constructed centrally or also decentrally. Other configurations are also conceivable.

The contact element can be connected to the coordinate measuring machine, for example, by means of a connecting element, for example with an adapter. The contact element can be designed to be removable and exchangeable from the coordinate measuring machine. The coordinate measuring machine can be a multisensor measuring machine which has additional sensors in addition to the contact element.

The evaluation unit can be set up to generate at least one piece of information about the measurement point on the surface of the measurement object from the signal. Information about the measuring point can basically be understood as any information about the measuring point, for example a position and / or coordinates of the measuring point in the coordinate system of the probe element, in particular spherical coordinates in the probe sphere coordinate system.

1. a) Antasten der mechanischen Referenz mit mindestens einem taktilen Tastelement eines taktilen Sensors eines Koordinatenmessgeräts an mindestens einem taktilen Messpunkt und Bestimmen von Koordinaten des taktilen Messpunkts in einem Koordinatensystem des Koordinatenmessgeräts;
2. b) Erzeugen mindestens eines Lichtflecks auf der Referenzoberfläche, wobei mindestens ein optisches Signal mit mindestens einem optischen System erzeugt wird, wobei in mindestens einer Beaufschlagungsposition des taktilen Tastelements im Koordinatensystem des Koordinatenmessgeräts die Referenzoberfläche mit dem optischen Signal durch das taktile Tastelement hindurch beaufschlagt wird,
3. c) Bestimmen der Position des Lichtflecks auf der Referenzoberfläche in dem Koordinatensystem der Referenzoberfläche und Erfassen von Koordinaten der Beaufschlagungsposition im Koordinatensystem des Koordinatenmessgeräts;
4. d) Bestimmen eines Zusammenhangs zwischen den Koordinaten der Beaufschlagungsposition im Koordinatensystem des Koordinatenmessgeräts und der Position des Lichtflecks auf der Referenzoberfläche in dem Koordinatensystem der Referenzoberfläche;
5. e) Bestimmen der Lage der Referenzoberfläche zu der mechanischen Referenz im Koordinatensystem des Koordinatenmessgeräts aus den in Verfahrensschritt a) bestimmten Koordinaten des taktilen Messpunkts und in Verfahrensschritt c) bestimmten Position des Lichtflecks unter Verwendung des in Verfahrensschritt d) bestimmten Zusammenhangs.

In a further aspect, a method for determining a position of a reference surface relative to a mechanical reference is proposed within the scope of the present invention. The procedure consists of the following steps:

1. a) probing the mechanical reference with at least one tactile probe element of a tactile sensor of a coordinate measuring machine at at least one tactile measuring point and determining coordinates of the tactile measuring point in a coordinate system of the coordinate measuring machine;
2. b) generating at least one light spot on the reference surface, wherein at least one optical signal is generated with at least one optical system, wherein in at least one application position of the tactile probe element in the coordinate system of the coordinate measuring device, the reference surface is subjected to the optical signal through the tactile probe element,
3. c) determining the position of the light spot on the reference surface in the coordinate system of the reference surface and detecting coordinates of the application position in the coordinate system of the coordinate measuring machine;
4. d) determining a relationship between the coordinates of the loading position in the coordinate system of the coordinate measuring machine and the position of the light spot on the reference surface in the coordinate system of the reference surface;
5. e) Determining the position of the reference surface to the mechanical reference in the coordinate system of the coordinate measuring machine from the coordinates of the tactile measuring point determined in method step a) and the position of the light spot determined in method step c) using the relationship determined in method step d).

Here, the method steps can be carried out in the specified order, with one or more of the steps also being able to be carried out at least partially simultaneously and with one or more of the steps being able to be repeated several times. Furthermore, further steps can additionally be carried out regardless of whether they are mentioned in the present application or not. For example, by using a plurality of positions in the coordinate system of the coordinate measuring machine and determining the corresponding positions of the light spot on the reference surface in the coordinate system of the reference surface, the reference surface can be calibrated. In this way, for example, the scaling and rotation of the two coordinate systems to one another can be determined.

A light indicator according to the invention is used in the method. For details with regard to the method according to the invention, reference is made to the description of the light indicator and contact element according to the invention.

A reference surface can be understood to mean a flat surface which has a reference dimension. For example, the reference surface can have a pixel array, in particular a matrix of pixels. For example, the reference surface can be a pixel array of a CCD chip. The pixel array, in particular the positioning of the pixels with respect to one another, can be used as a reference measure. For example, the reference surface can be a marker plate with at least one marker. A “mechanical reference” can be understood to mean an object of any shape, in particular at least one edge, which can be touched by tactile means.

The coordinate system of the coordinate measuring machine can be, for example, a Cartesian coordinate system or a spherical coordinate system. Other coordinate systems are also conceivable. The coordinate system of the coordinate measuring machine usually has a fixed zero point which is located in a corner of the usually cuboid measuring volume. During a measurement, at least one second coordinate system can be defined which has a marked point on the measurement object as the zero point.

A “tactile measuring point” can be understood as a point on a surface of the mechanical reference at which the tactile sensor interacts with the mechanical reference. The method can include a storage step in which the coordinates of the tactile measuring point are stored, for example in a data memory of the evaluation unit. “An application position of the tactile feeler element” can be understood to mean a predefined and / or predefinable position of the tactile feeler element in which the reference surface is acted upon by the optical signal.

“Determining the position of the light spot” can be understood to mean determining coordinates of the light spot, in particular a center point of the light spot, in the reference dimension. For example, the pixel array of the CCD chip can be read out and a pixel index, for example column and row, can be determined. For example, light spots projected onto the marker plate can be photographed together with the markers and a position of the light spot in relation to the markers can be determined. The method can include a storage step in which the coordinates of the light spot and the coordinates of the exposure position are stored, for example in a data memory of the Evaluation unit. “Acquisition of coordinates of the loading position” can be understood to mean one or more of reading, reading out, determining the coordinates. For example, the application position can be predefined or predefinable.

A relationship between the coordinates of the application position in the coordinate system of the coordinate measuring machine and the position of the light spot on the reference surface can be understood to mean any mathematical relationship that relates the coordinate system of the coordinate measuring machine to the coordinate system of the reference surface. In particular, the evaluation unit can be set up to determine the relationship.

The method can further include a determination of a relative position of the light spot with respect to the tactile probe element. A relative position can be understood to mean an offset and / or a shift from an optical and mechanical axis of the tactile sensor, in particular from the center point of the probe ball of the tactile probe element. A focal point of the optical signal, in particular a center point of the light spot, can deviate from the coordinates of the center point of the sphere. The method can have a calibration method in which this deviation is determined.

The devices according to the invention and the method according to the invention are advantageous over known methods and devices. A combination of a tactile sensor, an optical system and the application of the optical signal to the measurement object through the tactile probe element enables a determination of a pixel position of a CCD chip or a determination of a marker plate in space. By using the tactile probe element as the end lens of the optical system, it can be made possible that several measuring tasks can be combined and related to one another without changing the measuring head.

• Ausführungsform 1: Antastelement zur Vermessung mindestens eines Messobjekts umfassend
• mindestens einen taktilen Sensor, wobei der taktile Sensor mindestens ein taktiles Tastelement aufweist, welches eingerichtet ist, eine Oberfläche des Messobjekts taktil abzutasten; mindestens ein optisches System, wobei das optische System eingerichtet ist, mindestens ein optisches Signal zu erzeugen;
• wobei das Antastelement eingerichtet ist, das Messobjekt durch das taktile Tastelement hindurch mit dem optischen Signal zu beaufschlagen,
• wobei das optische System mindestens eine Abbildungsvorrichtung aufweist, welche eingerichtet ist, das Messobjekt zumindest teilweise abzubilden, und/oder wobei das optische System mindestens einen konfokalen Sensor aufweist, welcher eingerichtet ist, das Messobjekt berührungslos zu vermessen, und/oder wobei das optische System mindestens ein Autokollimationsfernrohr aufweist, welches eingerichtet ist, zu einer Winkelmessung des Messobjekts.

In summary, the following embodiments are particularly preferred in the context of the present invention:

• Embodiment 1: A contact element for measuring at least one measurement object comprising
• at least one tactile sensor, the tactile sensor having at least one tactile probe element which is set up to tactilely scan a surface of the measurement object; at least one optical system, wherein the optical system is set up to generate at least one optical signal;
• wherein the probe element is set up to apply the optical signal to the measurement object through the tactile probe element,
• wherein the optical system has at least one imaging device which is set up to at least partially image the measurement object, and / or wherein the optical system has at least one confocal sensor which is set up to measure the measurement object without contact, and / or wherein the optical system at least has an autocollimation telescope which is set up for an angle measurement of the measurement object.

Embodiment 2: Probing element according to the previous embodiment, the optical system being at least partially arranged in the tactile probe element.

Embodiment 3: Probing element according to one of the preceding embodiments, wherein the optical signal is a light beam.

Embodiment 4: Probing element according to one of the preceding embodiments, the tactile probe element being a terminating lens of the optical system in a direction of propagation of the optical signal from the tactile test element to the measurement object.

Embodiment 5: Probing element according to the previous embodiment, wherein the tactile probe element is set up to focus the optical signal on the measurement object.

Embodiment 6: Probing element according to one of the preceding embodiments, the probing element having at least one shaft for fastening the tactile probe element.

Embodiment 7: Probing element according to the preceding embodiment, the optical system being at least partially arranged in the shaft.

Embodiment 8: Probing element according to one of the two preceding embodiments, the shaft having a length between 20 mm and 240 mm.

Embodiment 9: Probing element according to one of the three preceding embodiments, the shaft having a rigidity which ensures that with a tactile measuring force of 200 mN a deflection occurs that is significantly smaller than 1 μm.

Embodiment 10: Probing element according to one of the preceding embodiments, wherein the tactile feeler element has at least one hole in which the optical system is at least partially arranged, the hole being selected from a through hole and a blind hole.

Embodiment 11: Probing element according to the preceding embodiment, the bore being arranged perpendicular to the shaft or in a direction of extent of the shaft.

Embodiment 12: Probing element according to one of the preceding embodiments, the tactile probe element having a probe ball.

Embodiment 13: Probing element according to one of the preceding embodiments, wherein the tactile feeler element is made of an at least partially transparent material, wherein the at least partially transparent material is glass.

Embodiment 14: probe element according to one of the preceding embodiments, wherein the tactile probe element is made of a non-transparent material, the non-transparent material being ruby.

Embodiment 15: Probing element according to one of the preceding embodiments, the optical system having at least one lighting device.

Embodiment 16: Probing element according to the previous embodiment, the lighting device being set up to generate the optical signal and to illuminate the measurement object through the tactile probe element.

Embodiment 17: Probing element according to the previous embodiment, the lighting device being set up to generate a light spot on the measurement object, the light spot having a diameter of less than 10 μm.

Embodiment 18: Probing element according to one of the three preceding embodiments, wherein the lighting device has at least one light source.

Embodiment 19: Probing element according to the preceding embodiment, the light source being selected from at least one light-emitting diode and at least one laser diode, in particular a fiber-coupled laser diode.

Embodiment 20: Probing element according to one of the preceding embodiments, the optical system having at least one light guide.

Embodiment 21: Probing element according to the preceding embodiment, the light guide having at least one optical fiber selected from at least one singlemode fiber or at least one multimode fiber.

Embodiment 22: Probing element according to one of the six preceding embodiments, the optical system having at least one lens which is set up to focus the optical signal generated by the lighting device on the measurement object.

Embodiment 23: Light indicator comprising a contact element, wherein the contact element comprises at least one tactile sensor, wherein the tactile sensor has at least one tactile sensor element which is set up to tactilely scan a surface of the measurement object, wherein the contact element comprises at least one optical system, the optical The system is set up to generate at least one optical signal, the contact element being set up to apply the optical signal to the measurement object through the tactile probe element, the optical system having at least one lighting device, the lighting device being set up to supply the optical signal generate, wherein the contact element is set up to apply the optical signal to the object through the tactile feeler element, the contact element having a contact element according to one of the preceding embodiments relating to a contact element.

• mindestens ein Antastelement nach einem der vorherigen, ein Antastelement betreffenden, Ausführungsformen,
• mindestens eine Auswerteeinheit, welche eingerichtet ist, um mindestens eine Information über einen Messpunkt an einer Oberfläche des Messobjekts zu erzeugen.

Embodiment 24: Coordinate measuring machine for measuring at least one measurement object comprising:

• at least one contact element according to one of the previous embodiments relating to a contact element,
• at least one evaluation unit which is set up to generate at least one item of information about a measuring point on a surface of the measuring object.

1. a) Antasten der mechanischen Referenz mit mindestens einem taktilen Tastelement eines taktilen Sensors eines Koordinatenmessgeräts an mindestens einem taktilen Messpunkt und Bestimmen von Koordinaten des taktilen Messpunkts in einem Koordinatensystem des Koordinatenmessgeräts;
2. b) Erzeugen mindestens eines Lichtflecks auf der Referenzoberfläche, wobei mindestens ein optisches Signal mit mindestens einem optischen System erzeugt wird, wobei in mindestens einer Beaufschlagungsposition des taktilen Tastelements im Koordinatensystem des Koordinatenmessgeräts die Referenzoberfläche mit dem optischen Signal durch das taktile Tastelement hindurch beaufschlagt wird,
3. c) Bestimmen der Position des Lichtflecks auf der Referenzoberfläche in dem Koordinatensystem der Referenzoberfläche und Erfassen von Koordinaten der Beaufschlagungsposition im Koordinatensystem des Koordinatenmessgeräts;
4. d) Bestimmen eines Zusammenhangs zwischen den Koordinaten der Beaufschlagungsposition im Koordinatensystem des Koordinatenmessgeräts und der Position des Lichtflecks auf der Referenzoberfläche in dem Koordinatensystem der Referenzoberfläche;
5. e) Bestimmen der Lage der Referenzoberfläche zu der mechanischen Referenz im Koordinatensystem des Koordinatenmessgeräts aus den in Verfahrensschritt a) bestimmten Koordinaten des taktilen Messpunkts und in Verfahrensschritt c) bestimmten Position des Lichtflecks unter Verwendung des in Verfahrensschritt d) bestimmten Zusammenhangs, wobei in dem Verfahren ein Lichtanzeiger nach einer der vorhergehenden, einen Lichtanzeiger betreffenden, Ausführungsformen verwendet wird.

Embodiment 25: Method for determining a position of a reference surface in relation to a mechanical reference, comprising the following steps:

1. a) probing the mechanical reference with at least one tactile probe element of a tactile sensor of a coordinate measuring machine at at least one tactile measuring point and determining coordinates of the tactile measuring point in a coordinate system of the coordinate measuring machine;
2. b) generating at least one light spot on the reference surface, at least one optical signal is generated with at least one optical system, the reference surface being acted upon by the optical signal through the tactile probe element in at least one application position of the tactile probe element in the coordinate system of the coordinate measuring device,
3. c) determining the position of the light spot on the reference surface in the coordinate system of the reference surface and detecting coordinates of the application position in the coordinate system of the coordinate measuring machine;
4. d) determining a relationship between the coordinates of the loading position in the coordinate system of the coordinate measuring machine and the position of the light spot on the reference surface in the coordinate system of the reference surface;
5. e) Determination of the position of the reference surface to the mechanical reference in the coordinate system of the coordinate measuring machine from the coordinates of the tactile measuring point determined in method step a) and the position of the light spot determined in method step c) using the relationship determined in method step d), whereby in the method a Light indicator according to one of the preceding embodiments relating to a light indicator is used.

Embodiment 26: The method according to the preceding embodiment, the method comprising a determination of a relative position of the light spot with respect to the tactile probe element.

Figure list

Further details and features of the invention emerge from the following description of preferred exemplary embodiments, in particular in conjunction with the dependent claims. The respective features can be implemented individually or in combination with one another. The invention is not restricted to the exemplary embodiments. The exemplary embodiments are shown schematically in the figures. The same reference numbers in the individual figures designate elements that are the same or functionally the same or correspond to one another with regard to their functions.

• 1 eine schematische Darstellung eines Ausführungsbeispiels eines erfindungsgemäßen Antastelements;
• 2 eine schematische Darstellung eines Ausführungsbeispiels eines erfindungsgemäßen Lichtanzeigers;
• 3 eine schematische Darstellung eines Ausführungsbeispiels einer Bestimmung einer Lage einer Referenzoberfläche in einem Koordinatensystem eines Koordinatenmessgeräts; und
• 4A bis 4C schematische Darstellung weiterer Ausführungsbeispiele eines erfindungsgemäßen Antastelements.

Show in detail:

• 1 a schematic representation of an embodiment of a contact element according to the invention;
• 2 a schematic representation of an embodiment of a light indicator according to the invention;
• 3 a schematic representation of an embodiment of a determination of a position of a reference surface in a coordinate system of a coordinate measuring machine; and
• 4A to 4C schematic representation of further exemplary embodiments of a contact element according to the invention.

Embodiments

1 shows a schematic representation of an embodiment of a contact element according to the invention 110 for measuring at least one measurement object 112 . The contact element comprises at least one tactile sensor 114 . The tactile sensor 114 has at least one tactile probe element 116 , which is set up, a surface of the measurement object 112 tactile feel. The contact element 110 comprises at least one optical system 118 . The optical system 118 is set up an optical signal 120 to create. The contact element 110 is set up, the measurement object 112 through the tactile feeler element 116 through with the optical signal 120 to apply.

The tactile sensor 114 can be designed as a button. The tactile sensor 114 can have a shaft 122 for attaching the tactile probe element 116 exhibit. The tactile sensor 114 can use an adapter 124 for connecting the tactile sensor 114 with a further device, for example a coordinate measuring machine. For example, the tactile sensor 114 an optically, inductively or capacitively measuring tactile sensor 114 be.

The tactile touch element 116 can touch the target at at least one touch point 112 touch, for example at a measuring point on the surface of the measuring object 112 . The tactile touch element 116 can comprise a stylus ball. However, other probe elements are also conceivable. For example, the tactile probe element 116 the surface of the measuring object 112 touch, for example by bringing the surface of the measurement object into contact 112 with a surface of the tactile probe element 116 and / or the tactile probe element 116 can with the surface of the target 112 interact without contact, for example capacitively. During the interaction, the surface of the tactile probe element can be 116 and the surface of the target 112 touch. In particular, the surface of the tactile probe element can 116 and the surface of the Measurement object 112 electrically contact. Alternatively, the interaction can be non-contact, for example optical, inductive or capacitive.

The contact element 110 can be set up to generate at least one signal, for example an electronic signal, which is from the contact element 110 as a result of the interaction with the measurement object 112 is generated and / or which in response to the interaction with the measurement object 112 is produced. The signal can be evaluated, for example, by at least one evaluation unit in order to obtain at least one piece of information about the measuring point on the surface of the measuring object from the signal 112 to create.

The tactile touch element 116 can be set up the optical signal 120 through the tactile feeler element 116 at least partially to let through. The tactile touch element 116 can have transmissive properties. The tactile touch element 116 can be at least partially transparent to the optical signal 120 be. The tactile touch element 116 can be made of an at least partially transparent material. For example, the at least partially transparent material can be glass, for example a borosilicate glass, for example N-Bk7, or a high-index glass, for example S-LAH79, or a highly scratch-resistant glass.

The optical system 118 can at least partially in the tactile touch element 116 be arranged. The optical system 118 can at least partially in the tactile touch element 116 be integrated. The tactile touch element 116 can in particular at least one hole 126 have in which the optical system 118 is at least partially arranged. The hole 126 can be a blind hole. The tactile touch element 116 can for example be a light guide 128 have, for example at least one optical fiber. In the in 1 The embodiment shown, the bore can be arranged in a direction of extent of the shaft. The hole 126 can alternatively be perpendicular to the shaft 122 be arranged. The in 1 Shaft shown 122 a hole. The optical system 118 can at least partially in the shaft 122 be arranged. The shaft 122 can be set up the optical system 118 into the tactile probe element 116 to be coupled.

The tactile touch element 116 can in a direction of propagation of the optical signal 120 of the tactile probe element 116 to the measurement object 112 an end lens of the optical system 118 be. The optical signal 120 can be a ray of light. The tactile touch element 116 can be set up to direct the light beam onto the measurement object 112 to focus.

The shaft 122 can have a length between 20 and 240 mm. The shaft 122 can have a rigidity that ensures that a tactile measuring force of 200 mN results in a deflection that is significantly smaller than 1 µm.

The optical system 118 can at least one, not shown here, lighting device 130 exhibit. The lighting device 130 can be set up the optical signal 120 , in particular at least one light beam, to generate and the measurement object 112 through the tactile feeler element 116 to illuminate through. The lighting device 130 can be set up a light spot 134 on the measurement object 112 to create. The spot of light 134 can basically have any shape, preferably a circular area. The spot of light 134 can on the surface 112 of the measuring object have a diameter of less than 10 µm. The lighting device 130 can have at least one light source. The light source can be selected from at least one light-emitting diode and at least one laser diode, in particular a fiber-coupled laser diode. In particular, the light source can be set up to generate light with a wavelength of 620 nm to 700 nm. The light source can for example be a fiber-coupled laser diode with a wavelength of 635 nm. The optical system 118 can use the at least one light guide 128 exhibit. The light guide 128 can have a core and a jacket surface surrounding the core. The light guide 128 can have at least one optical fiber selected from at least one singlemode fiber or at least one multimode fiber. For example, a core diameter of a single-mode fiber can be from 3 µm to 9 µm. A numerical aperture, which is a measure of the opening angle at a fiber exit, can be approximately 0.1. For example, a core diameter of a multimode fiber can be from 50 µm to 1500 µm. The multimode fiber can be set up so that a multiplicity of modes can be found in the light guide 128 spread. A numerical aperture can be about 0.2 to 0.3. The lighting device 130 can have at least one coupling element which is set up for the optical signal generated by the light source 120 , especially the light beam 132 , into the light guide 128 to be coupled, in particular into an input of the light guide 128 . A diameter of the light spot 134 on the surface of the target 112 may depend on the core diameter of the optical fiber. The light guide 128 can have a core diameter that is as small as possible, so that the light spot is as small as possible 134 is generated, in particular a diameter of the light spot 134 smaller than 10 µm. A singlemode fiber can preferably be used. The light guide 128 can have the smallest possible opening angle so that losses due to scattered light be prevented. The light guide 128 can have a length of 0.1 m to 4 m, preferably a length of 1 m to 2 m.

The light guide 128 can at least partially in the tactile touch element 116 be integrated. For example, the light guide 128 in the hole 126 of the tactile probe element 116 be arranged. For example, a first part of the light guide 128 in the shaft 122 , in particular in a bore in the shaft 122 , be arranged and a second part of the light guide 128 in the tactile probe element 116 . The light guide 128 can have an output which is set up, the optical signal 120 to emit and the measurement object 112 with the optical signal 120 to apply. The output can be in the tactile probe element 116 be arranged. The contact element 110 can be set up, the output of the fiber in a size ratio 1: 1 on the measurement object 112 map. The blind hole can have a planar bottom. Due to the planar base and the radius of the glass ball, the tactile probe element 116 act as a plano-convex lens, and be set up by the light guide 128 emitted light on the surface of the measurement object 112 to focus.

In the in 2 embodiment shown, the tactile probe element 116 be made of an impermeable and / or non-transparent material, for example ruby. The optical signal 120 can through the tactile probe element 116 be directed. The tactile touch element 116 can in particular the at least one bore 126 exhibit. The tactile touch element 116 can for example use the light guide 128 have, for example at least one optical fiber. In the in 2 embodiment shown can the bore 126 be a through hole, the hole 126 in an extension direction of the shaft 122 can be arranged. The in 2 Shaft shown 122 a hole. The optical system 118 can at least partially in the shaft 122 be arranged. The shaft 122 can be set up the optical system 118 into the tactile probe element 116 to be coupled.

The optical system 118 can have at least one lens 136 have which is set up by the lighting device 130 generated optical signal 120 on the measurement object 112 to focus. The Lens 136 can in the hole 126 of the tactile probe element 116 be arranged. In particular, the lens 136 be a microlens. The Lens 136 can have a single lens or a lens system. The Lens 136 can be a plano-convex lens. For example, the lens 136 be made of barium glass, for example N-BAK2. For example, the refractive index of the lens 136 from 1.5 to 1.55 for a wavelength of 635 nm.

The ones in the 1 and 2 Embodiments shown can be in a light indicator 138 be used. The light indicator 138 can be set up the light spot 134 on the measurement object 112 to create. In 2 is the target 112 a pixel array 140 of a CCD chip. By reading out the CCD chip, it is possible to determine pixel coordinates, in particular rows and columns, of the light spot 134 respectively.

The light indicator 138 can be used to determine a position of a reference surface in relation to a mechanical reference 144 , for example an edge of the CCD chip, can be used, in particular using a coordinate measuring machine 142 . The reference surface can be the pixel array 140 be. The tactile touch element 116 can be the mechanical reference 144 touch at least one tactile measuring point and coordinate the tactile measuring point in a coordinate system of the coordinate measuring device 142 to be determined. Coordinates of an application position of the tactile probe element 116 , in particular a predefined and / or predeterminable application position, can in the coordinate system of the coordinate measuring device 142 are recorded, in particular are stored. A relationship between the coordinates of the application position in the coordinate system of the coordinate measuring machine and the pixel coordinates can be determined, for example using an evaluation unit of the coordinate measuring machine 142 . The determination of the position of the reference surface in relation to the mechanical reference 144 in the coordinate system of the coordinate measuring machine takes place from the specific coordinates of the tactile measuring point and the specific position of the light spot using the specific relationship.

3 shows a determination of a position of a marker plate 146 to the mechanical reference 144 . The marker board 146 can use a variety of markers 148 exhibit. The light indicator 138 can the light spot 134 on the marker plate 146 project. For example by means of a camera 150 can take a picture of the marker board 146 and the light spot 134 be recorded and a position of the light spot 134 on the marker board 146 to be determined. The tactile touch element 116 can be the mechanical reference 144 touch the at least one tactile measuring point. The coordinates of the tactile measuring point in the coordinate system of the coordinate measuring machine 142 can be determined. The coordinates of the application position of the tactile probe element 116 can in the coordinate system of the coordinate measuring machine 142 are detected and the relationship between the coordinates of the loading position in the coordinate system of the coordinate measuring machine and the position of the light spot 134 on the marker board 146 can be determined. Determining the location of the marker plate 146 to the mechanical reference 144 in the coordinate system of the coordinate measuring machine takes place from the specific coordinates of the tactile measuring point and the specific position of the light spot using the specific relationship.

4A to 4C show further exemplary embodiments of a contact element according to the invention 110 . The optical system 118 may have a plurality of optical elements selected from the group consisting of: at least one lens; at least one lens system; at least one beam splitter; at least one aperture; at least one reflector. 4A shows an embodiment in which the optical system 118 at least one imaging device 152 which is set up to at least partially image the measurement object. 4B shows an embodiment in which the optical system 118 at least one confocal sensor 154 which is set up, the measurement object 112 to be measured without contact. 4C shows an embodiment in which the optical system 118 at least one autocollimation telescope 156 which is set up for an angle measurement of the measurement object 112 .

List of reference symbols

110

Contact element

112

Measurement object

114

tactile sensor

116

tactile sensing element

118

optical system

120

optical signal

122

shaft

124

adapter

126

drilling

128

Light guide

130

Lighting device

132

Beam of light

134

Light spot

136

lens

138

Light indicator

140

Pixel array

142

Coordinate measuring machine

144

mechanical reference

146

Marker plate

148

marker

150

camera

152

Imaging device

154

confocal sensor

156

Autocollimation telescope

Claims (11)

Contact element (110) for measuring at least one measurement object (112) comprising - At least one tactile sensor (114), the tactile sensor (114) having at least one tactile probe element (116) which is set up to tactilely scan a surface of the measurement object (112); - At least one optical system (118), the optical system (118) being set up to generate at least one optical signal (120); wherein the contact element (110) is set up to apply the optical signal (120) to the measurement object (112) through the tactile feeler element (116), the optical system (118) having at least one imaging device (152) which is set up to at least partially image the measurement object (112), and / or wherein the optical system (118) has at least one confocal sensor (154) which is set up to measure the measurement object (112) without contact, and / or wherein the optical system ( 118) has at least one autocollimation telescope (156) which is set up to measure the angle of the measurement object (112). Probing element (110) according to the preceding claim, wherein the optical system (118) is at least partially arranged in the tactile probe element (116). Probing element (110) according to one of the preceding claims, wherein the tactile probe element (116) is a terminating lens of the optical system (118) in a direction of propagation of the optical signal (120) from the tactile test element (116) to the measurement object (112), wherein the tactile probe element (116) is set up to focus the optical signal (120) on the measurement object (112). Probing element (110) according to one of the preceding claims, wherein the tactile probe element (116) has at least one bore (126) in which the optical system (118) is at least partially arranged, the bore (126) being selected from a through bore and a blind hole. Probing element (110) according to one of the preceding claims, wherein the tactile probe element (116) is made of an at least partially transparent material, wherein the at least partially transparent material is glass. Probing element (110) according to one of the preceding claims, wherein the optical system (118) has at least one lighting device (130), wherein the lighting device (130) is set up to generate the optical signal (120) and the measurement object (112) through the to illuminate tactile probe element (116) through it. Probing element (110) according to the preceding claim, wherein the lighting device (130) is set up to generate a light spot (134) on the measurement object (112), the light spot (134) having a diameter of less than 10 µm. Probing element (110) according to one of the preceding claims, wherein the optical system (118) has at least one light guide (128). Light indicator (138) comprising a contact element (110), the contact element (110) comprising at least one tactile sensor (114), the tactile sensor (114) having at least one tactile feeler element (116) which is set up to be a surface of the measurement object (112) to scan tactilely, wherein the contact element (110) comprises at least one optical system (118), wherein the optical system (118) is set up to generate at least one optical signal (120), wherein the contact element (110) is set up, to apply the optical signal (120) to the measurement object (112) through the tactile probe element (116), the optical system (118) having at least one lighting device (130), the lighting device (130) being set up to the optical signal (120), wherein the contact element (110) is set up to apply the optical signal (120) to the measurement object (112) through the tactile feeler element (116), the on sensing element (110) has a sensing element according to one of the preceding claims relating to a sensing element. Coordinate measuring machine (142) for measuring at least one measurement object (112) comprising: - At least one contact element (110) according to one of the preceding claims relating to a contact element, - At least one evaluation unit which is set up to generate at least one item of information about a measuring point on a surface of the measuring object (112). Method for determining a position of a reference surface in relation to a mechanical reference, comprising the following steps: a) probing the mechanical reference with at least one tactile probe element (116) of a tactile sensor (114) of a coordinate measuring device (142) at at least one tactile measuring point and determining coordinates of the tactile measuring point in a coordinate system of the coordinate measuring device (142); b) generating at least one light spot (134) on the reference surface, at least one optical signal (120) being generated with at least one optical system (118), wherein in at least one application position of the tactile probe element (116) in the coordinate system of the coordinate measuring device (142) the reference surface is acted upon with the optical signal (120) through the tactile probe element (116), c) determining the position of the light spot (134) on the reference surface in the coordinate system of the reference surface and detecting coordinates of the application position in the coordinate system of the coordinate measuring machine (142); d) determining a relationship between the coordinates of the loading position in the coordinate system of the coordinate measuring machine (142) and the position of the light spot (134) on the reference surface in the coordinate system of the reference surface; e) determining the position of the reference surface to the mechanical reference in the coordinate system of the coordinate measuring machine (142) from the coordinates of the tactile measuring point determined in step a) and the position of the light spot determined in step c) using the relationship determined in step d), wherein in the method using a light indicator (138) according to any preceding claim relating to a light indicator.

Images