DE102018201211A1 - Chromatic confocal multi-spot sensor for determining coordinates of a DUT - Google Patents

Abstract

A lens (112) for a chromatic confocal multi-spot sensor (110) is proposed. The objective (112) has at least one first lens group (114) and at least one second lens group (116). The first lens group (114) is arranged in the propagation direction (118) of at least one first illumination light beam (120) and at least one second illumination light beam (122) in front of a pupil (124) and the second lens group (116) behind the pupil (124). In the propagation direction (118) of the first illumination light beam (120) and the second illumination light beam (122) behind the second lens group (116), the objective (112) has at least one deflection device (126) which is set up, the propagation direction (118) of the illumination light beams (120, 122). The first lens group (114) and the second lens group (116) have chromatic aberrative properties. The first lens group (114) and the second lens group (116) are arranged to focus portions of the first illumination light beam (120) as a function of the wavelength at at least two first measurement points (128) along an optical axis (130) of the objective (112) and to focus portions of the second illumination light beam (122) as a function of wavelength at at least two second measurement points (132) along the optical axis (130) of the objective (112). The first lens group (114) is arranged to generate a first longitudinal color aberration. The second lens group (116) is arranged to produce a second longitudinal color aberration, wherein the first longitudinal chromatic aberration and the second longitudinal chromatic aberration differ considerably. The first lens group (114) and the second lens group (116) are arranged to generate a lateral chromatic aberration such that the at least two first measurement points (128) and the at least two second measurement points (132) at each measurement depth are substantially parallel to the optical axis (130) extending straight lines (140) are arranged.

Description

Field of the invention

The invention relates to a lens for a chromatic confocal multi-spot sensor, a chromatically confocal multi-spot sensor and a method for determining coordinates of at least two different destinations of at least one measurement object. In particular, the present invention relates to the field of coordinate metrology using a non-contact coordinate measuring machine.

State of the art

Various devices and methods for determining coordinates of at least two different destinations of a measurement object, in particular an extended measurement object, are known from the prior art. For example, methods for topography surveying, such as triangulation methods, deflectometry or fringe projections, are known. These methods can be used for full-surface measurements over larger areas down to the square meter area. However, with such methods, no accuracies required for the coordinate metrology, for example up to the nanometer range, can be achieved.

Also known are confocal and confocal chromatic distance sensors, so-called confocal chromatic point sensors. In such sensors, a depth determination is carried out by an evaluation of an intensity distribution along a distance coordinate z, also called height coordinate. Confocal chromatic sensors allow a measurement of the distance coordinate z with a single image. Basically, chromatic aberration sensing lenses are used in such sensors which focus portions of a light beam having different wavelengths in different focal planes along an optical axis of the sensor. Each wavelength of the light beam can be assigned to a distance coordinate. If a focus of a wavelength is located on a surface of the measurement object, an intensity maximum can be measured for a sensor element of the confocal chromatic sensor for this wavelength and thus the depth can be determined.

Also known are confocal chromatic multi-spot sensors, which allow a parallelized depth measurement at many different measuring points simultaneously. For example, as in FR 2 950 441 A1 described an object-side telecentric arrangement of the beams used to the measuring points. Such an arrangement ensures that a measuring grid is the same at every depth, and an angle of incidence for all measuring points is the same. Next describes US 8,477,320 B2 a method for measuring the shape of a portion of a semitransparent object with a broadband spectrum light source in a multifocal illumination pattern generating device, a lens having a large chromatic aberration for imaging foci of the illumination patterns on the object, and detecting wavelength spectrum spectrometry detection means foci which are confocally imaged on the object via the lens, a position of a spectral peak for each focus being determined from the respective wavelength spectrum from which an extent of the object in the direction of the imaging beam (Z coordinate) is calculated.

In the case of an object-side telecentric confocal-chromatic multi-spot sensor, however, the diameter of a field-closest optic is already determined by a working distance, the size of a measuring field in the radial direction and in z, and the numerical aperture. For example, when using a deflection prism with NA = 0.1, working distance 5 mm and measuring range 10x10x10 mm results in an edge length of a first prism of about 16 mm. When object-side telecentricity is eliminated, the edge length of the prism can be reduced with otherwise unchanged properties, without significantly changing a design of the confocal-chromatic multispotsensor. The disadvantage, however, is that the size of the measuring field changes with the depth. Without further measures, principal rays essentially coincide, so that at a smaller distance the field is correspondingly smaller, or for the greatest distance the measuring field has to be correspondingly increased, which reduces the grid density.

Object of the invention

It is therefore an object of the present invention to provide an objective for a chromatically confocal multi-spot sensor, a chromatically confocal multi-spot sensor and a method which at least largely avoid the disadvantages of known devices and methods. In particular, a reduction in the size of chromatically confocal multispotsensoren should be made possible.

Disclosure of the invention

This object is achieved by a device and a method having the features of the independent claims. Preferred embodiments, which can be implemented individually or in combination, are shown in the dependent claims.

Hereinafter, the terms "having", "having", "including" or "including" or any grammatical variations thereof are used in a non-exclusive manner. Accordingly, these terms may refer to situations in which, in addition to the feature introduced by these terms, there are no other features, or to situations in which one or more other features are present. For example, the expression "A has B", "A has B", "A includes B" or "A includes B" can both 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 in A are present, for example element C, elements C and D or even further elements ,

It is further to be understood that the terms "at least one" and "one or more" and grammatical variations of these terms or similar terms, when used in conjunction with one or more elements or features, are intended to express that element or feature in a simple manner or may be provided more than once, as a rule be used only once, for example, at the first introduction of the feature or element. In a subsequent re-mention of the feature or element, the corresponding term "at least one" or "one or more" is generally no longer used, without limiting the possibility that the feature or element may be single or multiple.

Furthermore, the terms "preferably", "in particular", "for example" or similar terms are used below in connection with optional features, without restricting alternative embodiments thereof. Thus, features introduced by these terms are optional features, and it is not intended by these features to limit the scope of the claims and, in particular, the independent claims. Thus, as those skilled in the art will recognize, the invention may be practiced using other embodiments. Similarly, features introduced by "in one embodiment of the invention" or by "in one embodiment of the invention" are to be understood as optional features without, however, being construed as limiting alternative embodiments or the scope of the independent claims. Furthermore, these introductory expressions are intended to preserve all possibilities of combining the features introduced thereby with other features, be they optional or non-optional features.

In a first aspect of the present invention, an objective for a chromatic confocal multi-spot sensor is proposed. In principle, an objective can be understood to mean an optical system, in particular a real image-forming optical system, having at least one optical element. A chromatically confocal multispotsensor can be understood to mean a chromatically confocal sensor in which a test object to be examined is illuminated simultaneously at several destinations, thus allowing a simultaneous determination of longitudinal coordinates at several destinations. Chromatic confocal multi-spot sensors allow parallelized depth measurement at many points simultaneously. A chromatic confocal sensor can basically be understood to mean an optical sensor which has at least one confocal chromatic beam path. In the context of the present invention, the term "beam path" can be understood to mean a course of light beams through optical elements. In the context of the present invention, a "chromatically confocal beam path" can be understood as a beam path in which an illumination beam path and a detection beam path are confocal for at least one wavelength of an illumination light beam. In particular, for at least one wavelength of the illumination light beam, the condition may be satisfied that a first focus is at a destination on a surface of the measurement object and at the same time a second focus is at a point in a center of an aperture element which is in a propagation direction of one of the Measured object remitted light beam is arranged in front of a sensor element. The confocal chromatic sensor can be set up to measure a measurement object, in particular a surface and / or a surface contour of a measurement object. In particular, the confocal chromatic sensor may be a non-contact distance sensor in the field of coordinate metrology or may be used in a non-contact distance sensor.

In the context of the present invention, a measuring object can generally be understood to be an arbitrarily shaped object to be measured. For example, the measurement object may be selected from the group consisting of a test object, a workpiece to be measured and a component to be measured, for example a motor vehicle. Other measurement objects are also conceivable. In particular, the measurement object may be a planar measurement object, for example with an extended surface. The surface can be at least partially be reflective. Under partially reflective, it can be understood that the surface of the measurement object is set up to reflect and / or remit at least a portion of an illumination light beam.

The objective has at least one first lens group and at least one second lens group. The first lens group is arranged in the propagation direction of at least one first illumination light beam and at least one second illumination light beam in front of a pupil and the second lens group behind the pupil. In the propagation direction of the first illumination light beam and the second illumination light beam behind the second lens group, the objective has at least one deflection device which is set up to change the propagation direction of the illumination light beams. The first lens group and the second lens group have chromatic aberrative properties. The first lens group and the second lens group are arranged to focus portions of the first illumination light beam as a function of the wavelength at at least two first measurement points along an optical axis of the objective and portions of the second illumination light beam as a function of the wavelength at at least two second measurement points along the optical Axis of the lens to focus. The term "focusing along the optical axis" can be understood as focusing in the direction of the optical axis, in particular on the optical axis or parallel to the optical axis. The first lens group is arranged to produce a first chromatic aberration. The second lens group is arranged to produce a second longitudinal color aberration. The first chromatic aberration and the second chromatic aberration differ significantly. The first lens group and the second lens group are set up to produce a lateral chromatic aberration such that the at least two first measurement points and the at least two second measurement points are arranged at each measurement depth on lines extending essentially parallel to the optical axis.

A lens group can be understood as an optical element which has at least two lens elements. The first lens group may be referred to as the first imaging optics and the second lens group as the second imaging optics. The first and second lens groups may include a plurality of lens elements. The lens elements may be selected from the group consisting of: at least one concave-convex lens, at least one convex-concave lens, at least one biconvex lens, at least one plano-convex lens. The terms "first" and "second" are to be understood as pure designations and, in particular, provide no information about an order or whether the objective has further optical elements, in particular lens groups. The objective may comprise a multiplicity of lens elements, in particular lens groups or individual lens elements, for example a third and a fourth lens group.

The first lens group is arranged in the propagation direction of the at least one first illumination light beam and the at least one second illumination light beam in front of the pupil and the second lens group behind the pupil. A pupil can be understood to mean a diaphragm which limits a radiation cone of the illuminating light beam, or an image thereof, i. the pupil can be a real or virtual pupil. The term "before" or "after" refers to the beam path in the direction of illumination.

In the propagation direction of the first illumination light beam and the second illumination light beam behind the second lens group, the objective has at least one deflection device. The deflection device is set up to change the direction of propagation of the illumination light beams, in particular to deflect them in a predetermined or predeterminable direction. The deflection device can be set up to deflect the illumination light beams perpendicular to the direction of propagation. However, other changes in direction are conceivable. A deflecting device can be understood to be a basically arbitrary optical element which is set up to change the propagation direction of the illuminating light beams in a predetermined or predeterminable direction. The deflection device may comprise an element selected from the group consisting of: a prism, in particular a deflection prism, a mirror. For example, the deflection device may be a prism with an edge length of 16 mm. Preferably, the edge length may be less than 16 mm, for example, the edge length may be 12 mm. However, other edge lengths are conceivable, in particular shorter edge lengths. For example, the edge length in relation to the size of the measuring volume <1.2 as here in the embodiment, ideally even <1, be. The first lens group and the second lens group have chromatic aberrative properties. By the term "chromatic aberrative" properties it can be understood that the lens groups can be arranged to separate portions of the illumination light beam as a function of wavelength. For example, the first lens group and the second lens group may include at least one chromatic aberration lens. The first lens group and the second lens group are arranged to focus portions of the first illumination light beam as a function of the wavelength at at least two first measurement points along an optical axis of the objective, and Focusing portions of the second illumination light beam as a function of the wavelength at at least two second measurement points along the optical axis of the objective. A "measuring point" can be understood as a point at which a portion of one of the illumination light beams is focused. The terms "first" and "second" measuring points are to be understood as pure designations and in particular provide no information about an order or whether further measuring points are provided. The first lens group and the second lens group may form a hyperchromatic optical system. The at least two first measuring points can be arranged in different focal planes. The at least two second measuring points can be arranged in different focal planes. A focal plane, also referred to as a focal plane, can be understood to mean a plane perpendicular to the optical axis, in which at least one focal point, also called focal point, of the hyperchromatic optical system is arranged for at least one wavelength. In particular, the hyperchromatic optical system may be configured to focus a plurality of portions of the illumination light beams as a function of the wavelength at a plurality of different focal planes along the optical axis. For example, a first portion of the first illumination light beam having a first wavelength in a first focal plane, for example, at the first first measurement point, in particular a first z-coordinate, focused, and a second portion of the first illumination light beam having a second wavelength, which of the first Wavelength is different, can be focused in a second focal plane, for example, the second first measuring point, in particular a second z-coordinate, which is different from the first first measuring point. For example, a first portion of the second illumination light beam having a first wavelength in a first focal plane, for example at the second first measurement point, in particular a first z-coordinate, focused, and a second portion of the second illumination light beam having a second wavelength, which of the first Wavelength is different, can be focused in a second focal plane, for example, the second second measuring point, in particular a second z-coordinate, which is different from the second first measuring point. The lens can be chromatically uncorrected.

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, the range from 780 nm to 1.4 μm as near infrared (NIR), and the range of 15 microns to 1000 microns is referred to as far infrared (FIR). The term ultraviolet basically comprises a spectral range of 100 nm to 380 nm. Preferably, in the context of the present invention, visible light, ie light from the visible spectral range, is used. The term "light beam" can basically be understood to mean a quantity of light which is emitted and / or emitted in a specific direction. The light beam can be a beam. The term "illumination light beam" can be understood to mean a light beam which illuminates the measurement object, in particular the surface of the measurement object. The first and second illumination light beams may be generated by a lighting device. For example, the first and second illumination light beams can be generated as separate, in particular spatially separated, light beams from the illumination device. For example, the illumination device may be configured to generate an illumination light beam, which may be divided into at least two illumination light beams using optical elements, for example diaphragm elements having a plurality of hole elements.

The first lens group is arranged to produce a first chromatic aberration. The second lens group is arranged to produce a second longitudinal color aberration. A longitudinal chromatic aberration may be understood as an imaging characteristic such that two portions of a light beam of different wavelengths are focused at two different focal points as a function of the wavelength. The first longitudinal chromatic aberration and the second longitudinal chromatic aberration differ considerably. By "significantly different", it can be understood that the first longitudinal chromatic aberration and the second longitudinal chromatic aberration have opposite signs and / or at least one factor 3 differ. The longitudinal chromatic aberration generated by the lens groups before and after the pupil, or the respective groups closest to the field, can be at least one factor 3 , preferably by a factor 5 and more preferably by a factor 10 differ. Particularly preferred may be an embodiment in which the first longitudinal chromatic aberration and the second longitudinal chromatic aberration have opposite signs. The first lens group and the second lens group may be further configured to meet additional conditions for a secondary spectrum.

The first lens group and the second lens group are arranged to generate a lateral chromatic aberration such that the at least two first measuring points and the at least two second measuring points Measuring points are arranged in each measuring depth on substantially parallel to the optical axis extending straight lines. A lateral color aberration can be understood as an imaging property such that a magnification of the image depends on the wavelength of the incident light. In particular, the lateral chromatic aberration can be measured in a fixed reference plane as is usual. With respect to this reference plane, the beam heights of the main beams may be different even though the image size in the best focal plane is actually the same. For example, the lens groups, the first lens group and the second lens group system, may be configured to produce different sized images for different wavelengths. A measuring depth can be understood as a distance from the objective, in particular a longitudinal coordinate along the optical axis. By "substantially parallel" may be understood a parallel course, wherein deviations from a parallel course of 10%, preferably 5% and particularly preferably 1% are possible. Deviations from a parallel course can depend on production and adjustment. By "arranged on a straight line" can be understood an arrangement of the first measuring points and the second measuring point, in which the first measuring points and the second measuring points lie on a straight line, wherein deviations from the straight line, in particular by a secondary spectrum, are possible. In particular, the first measuring points and the second measuring points lie substantially on a straight line if there are more than two wavelengths or depth levels. The objective may be arranged to allow correction of the secondary spectrum, in particular to correct deviations from an arrangement on the line. In particular, the lens may have means for correcting the secondary spectrum, for example special glasses with anomalous partial dispersion. By "lines running essentially parallel to the optical axis" it can be understood that the at least two first measuring points and the at least two second measuring points for identical wavelengths have an identical longitudinal coordinate. In particular, the measuring points lie on an identical grid at each measuring depth. For example, the first illumination light beam and the second illumination light beam may each have a portion of a first wavelength λ ₁ and a portion having a second wavelength λ ₂ respectively. The objective, in particular the first and the second lens group, can be set up to determine the proportion of the first illumination light beam having the first wavelength at a first first measurement point f ₁ with a longitudinal coordinate z ₁ to focus and the proportion of the first illumination light beam with the second wavelength at a first second measuring point f ₂ with a longitudinal coordinate z ₂ to focus. The objective, in particular the first and the second lens group, can be set up to determine the proportion of the second illumination light beam having the first wavelength at a second first measurement point f ₃ with the longitudinal coordinate z ₁ to focus and the proportion of the second illumination light beam with the second wavelength at a second second measuring point f ₄ with the longitudinal coordinate z ₂ to focus. The measuring points f ₁ and f ₂ may be arranged such that they lie on a first straight line, which runs substantially parallel to the optical axis. The measuring points f ₃ and f ₄ may be arranged to lie on a second straight line which is substantially parallel to the optical axis. The objective may have an optical axis. The optical axis may be an optical axis of one or more of the optical elements of the objective. The optical axis can point in the direction of a sensor element. The optical axis may be an axis of a coordinate system of the objective, for example the z-axis. A longitudinal coordinate, in particular a distance coordinate, can be understood as a coordinate along the z-axis. Perpendicular to the z-axis further axes, such as x-axis and y-axis, may be provided. As stated above, the lens has a deflection device. The optical axis may be an optical axis of the deflection device.

In particular, the lateral chromatic aberration may be greater than 10% of the numerical aperture NA product of the objective and a depth measurement range. A "depth measuring range" can be understood as meaning a predetermined and / or adjustable and / or predeterminable measuring range in which a determination of the longitudinal coordinate takes place. The objective may be configured to provide a measurement volume of 10 × 10 × 10 mm ³ . The lateral chromatic aberration may correspond to a non-telecentric product and the depth measurement range. "Non-telecentric" can be understood as meaning a deviation from an axis-parallel course of main beams in the objective, in particular an angular difference. For example, lateral chromatic aberration can be determined from: lateral chromatic aberration [mm] = tan (angular difference) · depth measuring range [mm].

The first and second lens groups may be arranged such that the first illumination light beam and the second illumination light beam, in particular their main beams, are non-telecentric on the object side. The lens can be a non-telecentric lens. The objective can be set up to introduce as much lateral chromatic aberration in addition to the longitudinal chromatic aberration that the at least two first measuring points and the at least two second measuring points continue to lie on a grid which is substantially identical in each measuring depth. Under "substantially identical grid" it can be understood that the at least two first measuring points and the at least two second measuring points lie on an identical grid in each measuring depth, wherein deviations from the identical grid, in particular by a secondary spectrum, are possible. Under "object-side non-telecentric" can be understood that the object side, a deviation from an axis-parallel course of main rays in the lens are possible. "Object-side" refers to the object to be measured and not to the object in the sense of the optical image, the image of which lies on the measurement object.

As stated above, the objective may comprise a plurality of lens elements, in particular lens groups or individual lens elements, for example a third and a fourth lens group. The further lens elements can be set up to produce a lateral color aberration and / or a longitudinal chromatic aberration. For example, a further lens element in the direction of propagation of the illumination light beam can be arranged in front of the first lens group and a further lens element in the propagation direction of the illumination light beam can be arranged behind the second lens group. By way of example, the further lens groups can be set up to increase the lateral color aberrations and / or color longitudinal errors generated by the first and second lens groups. For example, the other lens groups can produce a transverse color error with the same sign and thus produce longitudinal chromatic aberrations with opposite sign.

The objective can have at least one illumination diaphragm with at least two illumination diaphragm aperture elements. The illumination panel may include a plurality of illumination aperture hole elements. In the context of the present invention, a "diaphragm" can basically be understood to mean an optical element or component of the objective which is set up to limit an expansion of a radiation beam. A "lighting panel" can be understood to mean a panel which is arranged, for example, in front of the lighting apparatus and is illuminated by the lighting apparatus. In the context of the present invention, a "hole element" can be understood to mean a basically arbitrarily shaped opening. The objective can have at least one confocal diaphragm, also called a detection pinhole, with at least two confocal shutter hole elements. The illumination diaphragm and the confocal diaphragm can be designed as optical elements with at least two arbitrarily shaped and / or adjustable and / or adjustable openings. The illumination diaphragm and / or the confocal diaphragm can have a multiplicity of perforated elements, for example a perforated grid of a plurality of holes. The confocal aperture may include a plurality of confocal aperture hole elements. A "confocal diaphragm" can be understood as meaning any diaphragm which is arranged in a plane conjugate to the illumination diaphragm, in particular at the same distance from the first lens group as the illumination diaphragm, against the illumination direction in front of a sensor element and is arranged, defocused components of a detection light beam, in particular strongly defocused shares, hide and pass focused shares. An arrangement, in particular a position, the confocal diaphragm can be dependent on the measurement object, a quantity of light and a desired resolution, for example a lateral resolution and / or resolution of the distance determination. "A detection light beam" can be understood as a light beam which is reflected by the measurement object, in particular by the surface of the measurement object, and can be detected by a sensor element. The detection light beam may have a propagation direction such that the detection light beam illuminates the confocal diaphragm and the sensor element.

The lateral chromatic aberration can be greater than the diameter of an image of one or both confocal aperture hole elements in an image plane, as a transverse deviation in a middle plane. For maximum z-resolution, a diameter of the holes may typically be in the range of the diameter of the diffraction disk.

A distance between two perforated elements of the illumination diaphragm and / or the confocal diaphragm may be such that confocal conditions are met. Confocality conditions can be understood as the condition that defocused portions of the detection light beam are masked out and only focused portions fall into a hole element and are transmitted. In particular, the distance between two adjacent hole elements may be such that highly defocused light does not fall into an adjacent hole element and is transmitted. The distance between two hole elements can be chosen such that overlap spectra of the hole elements.

The objective can have at least one transfer device. The transfer device may be configured as part of one of the lens groups or as a separate element. The transfer device can be set up to guide and / or direct light generated by the illumination device to the measurement object, in particular to the surface of the measurement object. Furthermore, the transfer device can be set up to guide and / or direct light reflected and / or reflected by the measurement object onto the confocal diaphragm. The transfer device may be selected from the group consisting of: at least one beam splitter; at least one lens; at least one lens group.

In another aspect, a chromatic confocal multi-spot sensor is proposed for determining longitudinal coordinates of at least two different destinations of at least one measurement object. The chromatic confocal multi-spot sensor comprises at least one objective according to the invention according to one of the embodiments described above or below. For details regarding the chromatic confocal multi-spot sensor, reference is made to the description of the objective according to the invention.

In the context of the present invention, the expression "destination" can be understood to mean a basically arbitrary location, in particular a point or a surface, on the surface of the measurement object to be measured, on which a determination of a longitudinal coordinate takes place. For example, a destination may be a measurement point on the surface of the measurement object. In the context of the present invention, "different destinations" may be understood to mean a spatial separation, for example in at least one spatial direction, of the destinations on the surface, the destinations being able to overlap at least partially. By "at least partially overlapping" it can be understood that the destinations are not completely congruent. In the context of the present invention, coordinates of a measurement object can be understood to mean coordinates on the surface to be measured of the measurement object, in particular distance coordinates. One or more coordinate systems can be used for this purpose. For example, a Cartesian coordinate system or a spherical coordinate system can be used. Other coordinate systems are also conceivable. A determination of a coordinate may, in particular, be understood as a determination of a distance between the respective destination of the measurement object and the chromatically confocal multi-spot sensor, for example a distance between the respective destination of the measurement object and at least one element of the chromatically confocal multispotsensor, in particular the sensor element and / or at least a confocal aperture. The chromatic confocal multi-spot sensor may be configured to determine at least one coordinate at a plurality of destinations, in particular simultaneously.

The chromatically confocal multi-spot sensor can have at least one illumination device that is set up to generate at least one illumination light beam. The illumination device may have at least one polychromatic light source and / or at least one white light source and / or at least one spectrally broadband light source. In the context of the present invention, a lighting device can be understood as any device which is set up to generate at least one light beam. The lighting device may have at least one light source. The illumination device can have at least one polychromatic light source and / or at least one white light source and / or at least one broadband light source. The light source may have a broad and evenly distributed spectral density. The illumination device can be set up to illuminate the measurement object through the illumination diaphragm. In the context of the present invention, the term "illuminating the object to be measured" can be understood to mean that the illuminating device is set up to illuminate the illuminating aperture and furthermore to illuminate the surface, in particular a point or an area on the surface, of the measuring object. The illumination device can furthermore have at least one further optical element, in particular a lens, which is set up to focus the light beam generated by the light source.

The chromatic confocal multi-spot sensor has at least one sensor element, wherein the sensor element is set up to detect at least two detection light beams reflected by the two destinations. The confocal aperture may be configured to illuminate the sensor element. For at least one wavelength of the illumination light beam, a focus may be on the surface of the measurement object. At the same time, a portion of the detection light beam for this wavelength can be focused in at least one hole element, in particular in exactly one hole element, the confocal shutter such that the intensity on the sensor element becomes maximum. The confocal diaphragm can be set up to hide all other unfocused spectral components of the detection light beam. In the context of the present invention, a "sensor element" can be understood as any device which is set up to detect at least one optical measured variable, for example an intensity, of the detection light beam and to generate a corresponding signal, for example an electrical signal, for example a analog and / or a digital signal.

The chromatically confocal multi-spot sensor can have at least one evaluation unit, which is set up to determine at least one spectral intensity distribution of the detection light beams and to determine from the respective spectral intensity distribution a longitudinal coordinate of the respective destination of the measurement object. Under a "spectral intensity distribution", a distribution of the intensity of the Detection light beam to be understood as a function of wavelength. The evaluation unit can be set up to determine a maximum of the respective spectral intensity distribution, to assign it to a wavelength and to determine from the assigned wavelength the longitudinal coordinate of the destination of the measurement object. The sensor element can be set up to determine at least one spectral distribution. The evaluation unit can be set up to determine at least one intensity maximum of the spectral distribution and to assign a wavelength to the intensity maximum. A determination of a spectral distribution can be understood as meaning a measurement and / or determination of the intensity of the detection light beam as a function of the wavelength. The spectral distribution may comprise an intensity distribution as a function of a wavelength. The sensor element can be and / or comprise a spectrally resolving detector. In particular, the sensor element may be and / or comprise a spectrometer. The sensor element may have at least one multi-spectral sensor.

In this context, "an evaluation unit" can generally be understood to mean an electronic device which is set up to evaluate signals generated by the sensor element. For example, one or more electronic connections between the sensor element and the evaluation unit can be provided for this purpose. The evaluation unit can comprise, for example, 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, wherein the data processing device can be set up, for example, by programming technology in order to control the sensor element. The evaluation unit may further comprise at least one interface, for example an electronic interface and / or a human-machine interface such as an input / output device such as a display and / or a keyboard. The evaluation unit can be constructed, for example, centrally or decentrally. Other embodiments are conceivable. The evaluation unit can be completely or partially integrated into the sensor element. The sensor element can be connected, for example, directly or indirectly to the evaluation unit. Alternatively or additionally, however, the evaluation unit may also be arranged completely or partially at the location of the sensor element, for example in the form of a microcontroller, and / or may be integrated wholly or partly into the sensor element.

As stated above, the distance between two hole elements can be selected such that spectra of the hole elements overlap. The evaluation unit can be set up to separate overlapping spatial and spectral information, in particular using at least one algorithmic method.

• - Erzeugen mindestens eines ersten Beleuchtungslichtstrahls und eines zweiten Beleuchtungslichtstrahls mit mindestens einer Beleuchtungsvorrichtung;
• - Beleuchten des Messobjekts mit den Beleuchtungslichtstrahlen durch eine Beleuchtungsblende mit mindestens zwei Beleuchtungslochelementen an den mindestens zwei Bestimmungsorten;
• - Fokussieren von Anteilen des ersten Beleuchtungslichtstrahls in Abhängigkeit von der Wellenlänge an mindestens zwei ersten Messpunkten entlang einer optischen Achse des Objektivs und Fokussieren von Anteilen des zweiten Beleuchtungslichtstrahls in Abhängigkeit von der Wellenlänge an mindestens zwei zweiten Messpunkten entlang der optischen Achse des Objektivs; wobei die erste Linsengruppe und die zweite Linsengruppe chromatisch aberrative Eigenschaften aufweisen;
• - Erzeugen eines ersten Farblängsfehler mit der ersten Linsengruppe und Erzeugen eines zweiten Farblängsfehlers mit der zweiten Linsengruppe, wobei sich der erste Farblängsfehler und der zweite Farblängsfehler erheblich unterscheiden,
• - Erzeugen eines Farbquerfehlers mit der ersten Linsengruppe und der zweite Linsengruppe derart, dass die mindestens zwei ersten Messpunkte und die mindestens zwei zweiten Messpunkte in jeder Messtiefe auf im Wesentlichen parallel zur optischen Achse verlaufenden Geraden angeordnet sind.

In a further aspect, a method for determining longitudinal coordinates of at least two different destinations of at least one measurement object is proposed. The method comprises the following method steps:

• Generating at least a first illumination light beam and a second illumination light beam with at least one illumination device;
• Illuminating the measurement object with the illumination light beams through an illumination diaphragm having at least two illumination hole elements at the at least two destinations;
• Focusing portions of the first illumination light beam as a function of the wavelength at at least two first measurement points along an optical axis of the objective and focusing proportions of the second illumination light beam as a function of the wavelength at at least two second measurement points along the optical axis of the objective; wherein the first lens group and the second lens group have chromatic aberrative properties;
• Generating a first longitudinal chromatic aberration with the first lens group and generating a second longitudinal chromatic aberration with the second lens group, the first longitudinal chromatic aberration and the second longitudinal chromatic aberration differing significantly,
• - Generating a lateral chromatic aberration with the first lens group and the second lens group such that the at least two first measuring points and the at least two second measuring points are arranged in each measuring depth on substantially parallel to the optical axis extending straight lines.

In this case, the method steps can be carried out in the order indicated, wherein one or more of the steps can be carried out at least partially simultaneously and wherein one or more of the steps can be repeated several times. In addition, further steps, whether mentioned in the present application or not, may be additionally performed.

In the method, in each case at least one detection light beam reflected by the destinations can be detected with a sensor element. In the process, at least a spectral intensity distribution of the detection light beams are determined and from the respective spectral intensity distribution a longitudinal coordinate of the respective destination of the measurement object are determined.

In the method, a chromatic confocal multi-spot sensor according to the invention can be used. For details relating to the inventive method, reference is made to the description of the inventive chromatically confocal Multispotsensors.

The device according to the invention and the method according to the invention are advantageous over known methods and devices. Allowing lateral chromatic aberration can allow a reduction in the size of chromatic confocal multi-spot sensors. By a task of object-side telecentric reduction of an edge length of a deflection device can be made possible. For example, it may be possible to use a prism as a deflection device with a reduced edge length of 12 mm with a constant depth measuring range.

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

Embodiment 1: Lens for a chromatically confocal multi-spot sensor, wherein the lens has at least one first lens group and at least one second lens group, wherein the first lens group arranged in the propagation direction of at least a first illumination light beam and at least a second illumination light beam in front of a pupil and the second lens group behind the pupil wherein the objective in the propagation direction of the first illumination light beam and the second illumination light beam behind the second lens group has at least one deflection device configured to change the propagation direction of the illumination light beams, the first lens group and the second lens group having chromatically aberrative properties Lens group and the second lens group are arranged, portions of the first illumination light beam as a function of the wavelength at least two first Me focal points along an optical axis of the objective and to focus portions of the second illumination light beam as a function of the wavelength at at least two second measurement points along the optical axis of the objective, wherein the first lens group is arranged to generate a first longitudinal chromatic aberration, wherein the second lens group is arranged to produce a second chromatic aberration, the first chromatic aberration and the second chromatic aberration differing significantly, wherein the first lens group and the second lens group are adapted to generate a lateral chromatic aberration such that the at least two first measurement points and the at least two second measurement points are arranged in each measuring depth on substantially parallel to the optical axis extending straight lines.

Embodiment 2: Lens according to the preceding embodiment, wherein the at least two first measuring points and the at least two second measuring points lie on an identical grid in each measuring depth.

Embodiment 3: Lens according to one of the preceding embodiments, wherein the first lens group and the second lens group are arranged such that the first illumination light beam and the second illumination light beam are non-telecentric on the object side.

Embodiment 4: Lens according to one of the preceding embodiments, wherein the lens is chromatically uncorrected.

Embodiment 5: Lens according to one of the preceding embodiments, wherein the lens has at least one illumination diaphragm with at least two illumination aperture hole elements.

Embodiment 6: Lens according to the previous embodiment, wherein the illumination stop has a plurality of illumination aperture hole elements.

Embodiment 7: Objective according to one of the preceding embodiments, wherein the objective has at least one confocal stop with at least two confocal aperture hole elements, wherein the lateral chromatic aberration in an image plane is greater than the diameter of an image of one or both confocal aperture hole elements.

Embodiment 8: Lens according to the previous embodiment, wherein the confocal shutter has a plurality of confocal shutter hole elements.

Embodiment 9: Lens according to one of the four preceding embodiments, wherein a distance between two hole elements of the illumination diaphragm and the confocal diaphragm is such that confocal conditions are met.

Embodiment 10: Lens according to one of the preceding embodiments, wherein the lateral color aberration is greater than 10% of the product of the numerical aperture NA of the objective and a depth measuring range.

Embodiment 11: Lens according to one of the preceding embodiments, wherein the lateral color aberration corresponds to a product of non-telecentric and the depth measuring range.

Embodiment 12: Lens according to one of the preceding embodiments, wherein the longitudinal chromatic aberrations generated by the lens groups before and after the pupil have an opposite sign or at least one factor with the same sign 3 , preferably by a factor 5 and more preferably by a factor 10 differ.

Embodiment 13: Chromatic confocal multi-spot sensor for determining longitudinal coordinates of at least two different destinations of at least one measurement object comprising at least one objective according to one of the preceding embodiments.

Embodiment 14: A chromatic confocal multi-spot sensor according to the preceding embodiment, wherein the chromatic confocal multi-spot sensor has at least one illumination device configured to generate at least one illumination light beam.

Embodiment 15: Chromatic Confocal Multispotsensor according to one of the two preceding embodiments, wherein the illumination device has at least one polychromatic light source and / or at least one white light source and / or at least one spectrally broadband light source.

Embodiment 16: Chromatic confocal multi-spot sensor according to one of the three preceding embodiments, wherein the illumination device is set up to illuminate the measurement object through the illumination diaphragm.

Embodiment 17: A chromatic confocal multi-spot sensor according to one of the three preceding embodiments, wherein the chromatic confocal multi-spot sensor has at least one sensor element, wherein the sensor element is configured to detect at least two detection light beams reflected from the two destinations.

Embodiment 18: Chromatic confocal multi-spot sensor according to the preceding embodiment, wherein the chromatically confocal multi-spot sensor has at least one evaluation unit which is set up to determine at least one spectral intensity distribution of the detection light beams and to determine from the respective spectral intensity distribution a longitudinal coordinate of the respective destination of the measurement object ,

Embodiment 19: Chromatic confocal multi-spot sensor according to the preceding embodiment, wherein the evaluation unit is set up to determine a maximum of the respective spectral intensity distribution, to assign a wavelength and to determine from the assigned wavelength the longitudinal coordinate of the destination of the measurement object.

• - Erzeugen mindestens eines ersten Beleuchtungslichtstrahls und eines zweiten Beleuchtungslichtstrahls mit mindestens einer Beleuchtungsvorrichtung;
• - Beleuchten des Messobjekts mit den Beleuchtungslichtstrahlen durch eine Beleuchtungsblende mit mindestens zwei Beleuchtungslochelementen an den mindestens zwei Bestimmungsorten;
• - Fokussieren von Anteilen des ersten Beleuchtungslichtstrahls in Abhängigkeit von der Wellenlänge an mindestens zwei ersten Messpunkten entlang einer optischen Achse des Objektivs und Fokussieren von Anteilen des zweiten Beleuchtungslichtstrahls in Abhängigkeit von der Wellenlänge an mindestens zwei zweiten Messpunkten entlang der optischen Achse des Objektivs; wobei die erste Linsengruppe und die zweite Linsengruppe chromatisch aberrative Eigenschaften aufweisen;
• - Erzeugen eines ersten Farblängsfehlers mit der ersten Linsengruppe und Erzeugen eines zweiten Farblängsfehlers mit der zweiten Linsengruppe, wobei sich der erste Farblängsfehler und der zweite Farblängsfehler erheblich unterscheiden,
• - Erzeugen eines Farbquerfehlers mit der ersten Linsengruppe und der zweite Linsengruppe derart, dass die mindestens zwei ersten Messpunkte und die mindestens zwei zweiten Messpunkte in jeder Messtiefe auf im Wesentlichen parallel zur optischen Achse verlaufenden Geraden angeordnet sind.

Embodiment 20: A method for determining longitudinal coordinates of at least two different destinations of at least one measurement object, the method comprising the following method steps:

• Generating at least a first illumination light beam and a second illumination light beam with at least one illumination device;
• Illuminating the measurement object with the illumination light beams through an illumination diaphragm having at least two illumination hole elements at the at least two destinations;
• Focusing portions of the first illumination light beam as a function of the wavelength at at least two first measurement points along an optical axis of the objective and focusing proportions of the second illumination light beam as a function of the wavelength at at least two second measurement points along the optical axis of the objective; wherein the first lens group and the second lens group have chromatic aberrative properties;
• Generating a first longitudinal chromatic aberration with the first lens group and generating a second longitudinal chromatic aberration with the second lens group, the first longitudinal chromatic aberration and the second longitudinal chromatic aberration differing significantly,
• - Generating a lateral chromatic aberration with the first lens group and the second lens group such that the at least two first measuring points and the at least two second measuring points are arranged in each measuring depth on substantially parallel to the optical axis extending straight lines.

Embodiment 21: Method according to the preceding embodiment, wherein in each case at least one detection light beam reflected by the destinations is detected by a sensor element, wherein in each case at least one spectral intensity distribution of the detection light beams is determined and from the respective spectral Intensity distribution is determined a longitudinal coordinate of the respective destination of the measurement object.

Embodiment 22: Method according to one of the two preceding embodiments, wherein a chromatic confocal multi-spot sensor according to one of the preceding claims relating to a chromatic confocal multi-spot sensor is used.

list of figures

Further details and features of the invention will become apparent from the following description of preferred embodiments, in particular in conjunction with the subclaims. In this case, the respective features can be implemented on their own or in combination with one another. The invention is not limited to the embodiments. The embodiments are shown schematically in the figures. The same reference numerals in the individual figures designate the same or functionally identical or with respect to their functions corresponding elements.

• 1 eine schematische Darstellung eines Ausführungsbeispiels eines erfindungsgemäßen chromatisch konfokalen Multispotsensors.

In detail shows:

• 1 a schematic representation of an embodiment of a chromatic confocal multispotsensor according to the invention.

embodiments

1 shows a schematic representation of an embodiment of a chromatic confocal multispotsensor according to the invention 110 , The chromatic confocal multi-spot sensor has a lens 112 on. The objective 112 has at least one first lens group 114 and at least one second lens group 116 on. The first lens group 114 is in the direction of propagation 118 at least one first illumination light beam 120 and at least one second illumination light beam 122 in front of a pupil 124 and the second lens group 116 arranged behind the pupil. The first lens group 114 and the second lens group 116 may have a plurality of lens elements. The lens elements may be selected from the group consisting of: at least one concave-convex lens, at least one convex-concave lens, at least one biconvex lens, at least one plano-convex lens. The objective 112 may comprise a plurality of lens elements, in particular lens groups or individual lens elements, for example a third and a fourth lens group.

The objective 112 points in the direction of propagation 118 of the first illumination light beam 120 and the second illumination light beam 122 behind the second lens group 116 at least one deflection device 126 on. The deflection device 126 is set up, the propagation direction of the illumination light beams 120 . 122 to change, in particular to deflect in a predetermined or predeterminable direction. The deflection device 126 can be set up, the illumination light beams 120 . 122 perpendicular to the propagation direction 118 redirect. However, other changes in direction are conceivable. The deflection device 116 may comprise an element selected from the group consisting of: a prism, in particular a deflection prism, a mirror. For example, the deflection device may be a prism with an edge length of 16 mm. Preferably, the edge length may be less than 16 mm, for example, the edge length may be 12 mm. However, other edge lengths are conceivable.

The first lens group 114 and the second lens group 116 have chromatic aberrative properties. The first lens group 114 and the second lens group 116 , in particular a system of the first lens group 114 and second lens group 116 , are arranged, portions of the first illumination light beam 120 depending on the wavelength at at least two first measuring points 128 along an optical axis 130 of the lens 112 to focus and portions of the second illumination light beam 122 as a function of the wavelength at at least two second measuring points 132 along the optical axis 130 to focus. The first lens group 114 and the second lens group 116 have chromatic aberrative properties. In 1 an embodiment is shown in which the first lens group 114 and the second lens group, in particular the first and second lens group system, the first illumination light beam 120 at three first measuring points and the second illuminating light beam 122 focused at three second measuring points. The first lens group 114 and the second lens group 116 can form a hyperchromatic optical system. The at least two first measuring points 128 can be arranged in different focal planes. The at least two second measuring points 132 can be arranged in different focal planes. In particular, the hyperchromatic optical system may be configured to have a plurality of portions of the illumination light beams 120 . 122 as a function of the wavelength at a plurality of different focal planes along the optical axis 130 to focus. For example, a first portion of the first illumination light beam 120 with a first wavelength in a first focal plane, for example at the first first measuring point 134 , in particular a first z-coordinate, and a second portion of the first illumination light beam 120 with a second Wavelength, which is different from the first wavelength, in a second focal plane, for example, the second first measuring point 136 , in particular a second z-coordinate, which of the first first measuring point 134 is different, to be focused. For example, a first portion of the second illumination light beam 122 with a first wavelength in a first focal plane, for example at the second first measuring point 134 , in particular a first z-coordinate, and a second portion of the second illumination light beam 122 with a second wavelength, which is different from the first wavelength, in a second focal plane, for example, the second second measuring point 136 , in particular a second z-coordinate, which of the second first measuring point 134 is different, to be focused. The objective 112 can be chromatically uncorrected.

The first illumination light beam 120 and second illumination light beam 122 can from a lighting device 138 be generated. For example, the first illumination light beam 120 and second illumination light beam 122 as separate, in particular spatially separated, light beams from the lighting device 138 be generated. For example, the lighting device 138 be configured to generate an illumination light beam, which can be divided into at least two illumination light beams using optical elements, such as aperture elements with a plurality of hole elements. The chromatic confocal multispotsensor 110 can enable a parallelized depth measurement at many points at the same time. The lighting device 120 may be configured to generate a plurality of illumination light beams, for example two, three, four, ten or more. FIG. 2 exemplarily shows an embodiment with two illumination light beams with a light bundle to the field edge and a light bundle to the center of the field.

The chromatic confocal multispotsensor 110 can the at least one lighting device 138 respectively. The lighting device 138 may comprise at least one polychromatic light source and / or at least one white light source and / or at least one spectrally broadband light source. The lighting device 138 can have at least one light source. The lighting device 138 may comprise at least one polychromatic light source and / or at least one white light source and / or at least one broadband light source. The light source may have a broad and evenly distributed spectral density. The lighting device 138 may further comprise at least one further optical element, in particular a lens, which is arranged to focus the light beam generated by the light source.

The first lens group 114 is set up to produce a first chromatic aberration. The second lens group 116 is set up to produce a second color longitudinal error. The first chromatic aberration and the second chromatic aberration differ significantly. The first lens group 114 and the second lens group 116 are arranged to produce a lateral chromatic aberration such that the at least two first measurement points 128 and the at least two second measurement points 132 at any measurement depth on substantially parallel to the optical axis 130 running straight lines 140 are arranged. The first longitudinal chromatic aberration and the second longitudinal chromatic aberration may have opposite signs and / or may be at least one factor 3 differ. That of the lens groups, in particular of the first lens group 114 and the second lens group 116 , before and after the pupil 124 , or the respective field next groups, generated longitudinal chromatic aberration may be at least one factor 3 , preferably by a factor 5 and more preferably by a factor 10 differ. For example, the lens groups 114 . 116 , in particular the system of the first lens group 114 and second lens group 116 be configured to produce images of different sizes for different wavelengths. The at least two first measuring points 128 and the at least two second measurement points 132 for identical wavelengths may have an identical longitudinal coordinate. In particular, the measuring points lie on an identical grid at each measuring depth 142 , For example, the first illumination light beam 120 and the second illumination light beam 122 each share a first wavelength λ ₁ and a portion having a second wavelength λ ₂ respectively. The objective 112 , in particular the first lens group 114 and the second lens group 116 , can be set, the proportion of the first illumination light beam 120 with the first wavelength at a first first measurement point f1 with a longitudinal coordinate z1 to focus and the proportion of the first illumination light beam 120 with the second wavelength at a first second measuring point f2 with a longitudinal coordinate z2 to focus. The objective 112 , in particular the first lens group 114 and the second lens group 116 , can be configured, the proportion of the second illumination light beam 122 with the first wavelength at a second first measurement point f3 with the longitudinal coordinate z1 to focus and the proportion of the second illumination light beam 122 with the second wavelength at a second second measurement point f4 with the longitudinal coordinate z2 to focus. The measuring points f1 and f2 may be arranged so that they are on a first straight line 144 which are substantially parallel to the optical axis 130 runs. The measuring points f3 and f4 may be arranged to be on a second straight line 146 which are substantially parallel to the optical axis 130 runs.

The optical axis 130 may be an optical axis of one or more of the optical elements of the objective 112 his. The optical axis can be viewed in the direction of a sensor element 148 demonstrate. The optical axis 130 may be an axis of a coordinate system of the lens, for example the z -Axis. Perpendicular to the z -Axis can have more axes, for example x -Axis and y -Axis, be provided. As stated above, the lens points 112 a deflection device 126 on. The optical axis 130 may be an optical axis of the deflecting device 126 his.

In particular, the lateral chromatic aberration may be greater than 10% of the numerical aperture NA product of the objective and a depth measurement range. The objective 112 can be set up, a measurement volume 150 of 10 × 10 × 10 mm ³ . The lateral chromatic aberration may correspond to a non-telecentric product and the depth measurement range. The first lens group 114 and the second lens group 116 may be arranged such that the first illumination light beam 120 and the second illumination light beam 122 , in particular their main rays, object-side non-telecentric. The objective 112 can be a non-telecentric lens. The objective 112 can be set up to introduce so much lateral chromatic aberration in addition to the longitudinal chromatic aberration that the at least two first measuring points 128 and the at least two second measurement points 132 continue on a grid that is identical in every measurement depth 142 lie.

The objective 112 may comprise a plurality of lens elements, in particular lens groups or individual lens elements, for example a third and a fourth lens group. The further lens elements can be set up to produce a lateral color aberration and / or a longitudinal chromatic aberration. For example, another lens element in the propagation direction of the illumination light beam 120 . 122 in front of the first lens group 114 be arranged and another lens element in the propagation direction of the illumination light beam 120 . 122 behind the second lens group 116 be arranged. By way of example, the further lens groups can be set up to increase the lateral color aberrations and / or color longitudinal errors generated by the first and second lens groups. For example, the other lens groups can produce a transverse color error with the same sign and thus produce longitudinal chromatic aberrations with opposite sign.

The objective 112 can have at least one lighting panel 152 with at least two lighting aperture elements 154 respectively. The lighting panel 152 may be a variety of illumination aperture elements 154 respectively. The objective 112 can have at least one confocal aperture 156 , also called detection pinhole, with at least two Konfokalblendenlochelementen 158 respectively. The lighting panel 152 and the confocal aperture 156 can be configured as optical elements with at least two arbitrarily shaped and / or adjustable and / or adjustable openings. The lighting panel 152 and / or the confocal aperture 156 may have a plurality of hole elements, such as a hole pattern of several holes. The confocal aperture may include a plurality of confocal aperture hole elements. The confocal aperture 156 may be arranged in a plane conjugate to the illumination diaphragm and be arranged, defocused portions of a detection light beam 160 , in particular strongly defocused portions, hide and pass focused portions. A distance between two hole elements of the lighting panel 152 and / or the confocal aperture 156 may be such that confocality conditions are met.

The lateral chromatic aberration can be greater than the diameter of an image of one or both confocal aperture hole elements in an image plane, as a transverse deviation in a middle plane.

The objective 112 can be at least one transfer device 162 respectively. The transfer device 162 may be configured as part of one of the lens groups or as a separate element. The transfer device 162 can be set up by the lighting device 138 to guide and / or direct light generated on a measurement object, in particular on the surface of the measurement object. Next, the transfer device 162 be set up to guide and / or direct light remitted and / or reflected light on the Konfokalblende. The transfer device 162 may be selected from the group consisting of: at least one beam splitter; at least one lens; at least one lens group.

The chromatic confocal multispotsensor 110 has the at least one sensor element 148 on, wherein the sensor element 148 is arranged, at least two of two destinations reflected detection light beams 162 to detect. The confocal aperture 156 can be set up, the sensor element 148 to illuminate. For at least one wavelength of the illumination light beam 120 . 122 There may be a focus on the surface of the DUT. At the same time, a portion of the detection light beam 162 for this wavelength in at least one hole element, especially in exactly one hole element, the confocal aperture be focused that the intensity on the sensor element 148 becomes maximum. The confocal aperture 156 can be set up, all other non-focused spectral components of the detection light beam 162 hide. The sensor element 148 may be an intensity of the detection light beam 162 capture and generate a corresponding signal, such as an electrical signal, such as an analog and / or digital signal.

The chromatic confocal multispotsensor 110 can be at least one evaluation unit 164 which is set up, in each case at least one spectral intensity distribution of the detection light beams 162 to determine and from the respective spectral intensity distribution to determine a longitudinal coordinate of the respective destination of the measurement object. The evaluation unit 164 may be arranged to determine a maximum of the respective spectral intensity distribution, to assign a wavelength and to determine from the assigned wavelength the longitudinal coordinate of the destination of the measurement object. The sensor element 148 may be arranged to determine at least one spectral distribution. The evaluation unit 164 may be arranged to determine at least one intensity maximum of the spectral distribution and to assign a wavelength to the intensity maximum. The spectral distribution may comprise an intensity distribution as a function of a wavelength. The sensor element 148 may be a spectrally resolving detector and / or include. In particular, the sensor element 148 be a spectrometer and / or include. The sensor element 148 may comprise at least one multi-spectral sensor.

Between the sensor element 148 and the evaluation unit 164 one or more electronic connections may be provided. The evaluation unit 164 For example, it may 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, wherein the data processing device can be set up, for example, by programming technology in order to control the sensor element. The evaluation unit 164 may further comprise at least one interface, such as 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 164 can for example be centrally or decentrally. Other embodiments are conceivable. The evaluation unit 164 can be wholly or partly into the sensor element 148 be integrated. The sensor element 148 can, for example, directly or indirectly with the evaluation unit 164 be connected. Alternatively or additionally, the evaluation unit 164 but also completely or partially at the location of the sensor element 148 be arranged, for example in the form of a microcontroller, and / or may be wholly or partly integrated into the sensor element.

LIST OF REFERENCE NUMBERS

110

Multi-spot sensor

112

lens

114

First lens group

116

Second lens group

118

propagation direction

120

First illumination beam

122

Second illumination beam

124

pupil

126

deflecting

128

First measuring points

130

Optical axis

132

Second measuring points

134

First first measuring point or first second measuring point

136

Second first measuring point or second second measuring point

138

lighting device

140

straight

142

grid

144

First straight

146

Second straight

148

sensor element

150

measuring volume

152

lighting diaphragm

154

Lighting aperture hole element

156

confocal diaphragm

158

Konfokalblendenlochelement

160

Detection light beam

162

transfer device

164

evaluation

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• FR 2950441 A1 [0004]
• US 8477320 B2 [0004]

Claims (10)

Lens (112) for a chromatic confocal multi-spot sensor (110), wherein the objective (112) comprises at least a first lens group (114) and at least one second lens group (116), wherein the first lens group (114) in the propagation direction (118) at least one first illumination light beam (120) and at least one second illumination light beam (122) in front of a pupil (124) and the second lens group (116) behind the pupil (124), wherein the objective (112) in the propagation direction (118) of the first illumination light beam ( 120) and the second illuminating light beam (122) behind the second lens group (116) comprises at least one deflecting device (126) arranged to change the propagation direction (118) of the illuminating light beams (120, 122), the first lens group (114) and the second lens group (116) have chromatic aberrative properties, wherein the first lens group (114) and the second lens group (116) are arranged to focus portions of the first illumination light beam (120) as a function of the wavelength at at least two first measurement points (128) along an optical axis (130) of the objective (112) and portions of the second illumination light beam (122) as a function of the wavelength at at least two second measurement points (132) along the optical axis (130) of the objective (112), wherein the first lens group (114) is adapted to generate a first longitudinal chromatic aberration, the second lens group (116) being arranged second longitudinal color aberration, wherein the first longitudinal chromatic aberration and the second longitudinal chromatic aberration differ significantly, wherein the first lens group (114) and the second lens group (116) are adapted to generate a lateral chromatic aberration such that the at least two first measurement points (128) and the at least two second measuring points (132) at each measuring depth, substantially parallel to the op tisch axis (130) extending straight lines (140) are arranged. Lens (112) according to the preceding claim, wherein the at least two first measuring points (128) and the at least two second measuring points (132) lie on an identical grid (142) at each measuring depth. The objective (112) according to one of the preceding claims, wherein the first lens group (114) and the second lens group (116) are arranged such that the first illumination light beam (120) and the second illumination light beam (122) are non-telecentric on the object side. The objective (112) according to one of the preceding claims, wherein the objective (112) has at least one confocal stop (156) with at least two confocal aperture hole elements (158), wherein the lateral chromatic aberration in an image plane is greater than the diameter of an image of one or both confocal aperture hole elements (158 ). The objective (112) of any of the preceding claims, wherein the lateral chromatic aberration is greater than 10% of the numerical aperture NA product of the objective (112) and a depth measurement range. The objective (112) of any one of the preceding claims, wherein the lateral chromatic aberration corresponds to a non-telecentric product and the depth measurement region. Lens (112) according to any one of the preceding claims, wherein the color longitudinal errors generated by the lens groups before and after the pupil (124) have an opposite sign or at the same sign by at least a factor of 3, preferably by a factor of 5 and more preferably by one Differentiate factor 10. Chromatic confocal multi-spot sensor (110) for determining longitudinal coordinates of at least two different destinations of at least one object to be measured comprising at least one objective (112) according to one of the preceding claims. A chromatic confocal multi-spot sensor (110) according to any one of the preceding claims relating to a chromatic confocal multi-spot sensor, wherein the chromatic confocal multi-spot sensor (110) comprises at least one sensor element (148), the sensor element (148) being arranged at least two detection light beams reflected from the two destinations (160), wherein the chromatically confocal multi-spot sensor (110) has at least one evaluation unit (164) which is set up to determine at least one spectral intensity distribution of the detection light beams (160) and from the respective spectral intensity distribution a longitudinal coordinate of the respective destination of the object to be measured. Method for determining longitudinal coordinates of at least two different destinations of at least one object to be measured, the method comprising the following method steps: - generating at least one first illumination light beam (120) and one second illumination light beam (122) with at least one illumination device (138); - Illuminating the measurement object with the illumination light beams (120, 122) through a lighting panel (152) with at least two Illumination hole elements (154) at the at least two destinations; - Focusing portions of the first illumination light beam (120) as a function of the wavelength at at least two first measuring points (128) along an optical axis (130) of the objective (112) and focusing proportions of the second illumination light beam (122) as a function of the wavelength at least two second measurement points (132) along the optical axis (130) of the objective (112), the first lens group (114) and the second lens group (116) having chromatic aberration properties; Generating a first longitudinal chromatic aberration with the first lens group (114) and generating a second longitudinal chromatic aberration with the second lens group (116), wherein the first longitudinal chromatic aberration and the second chromatic aberration differ significantly; generating a lateral chromatic aberration with the first lens group (114) and the first chromatic aberration second lens group (116) such that the at least two first measuring points (128) and the at least two second measuring points (132) are arranged at each measuring depth on lines (140) extending substantially parallel to the optical axis (130).

Images