WO2014053573A1

WO2014053573A1 - Method and device for illuminating and measuring an object

Info

Publication number: WO2014053573A1
Application number: PCT/EP2013/070592
Authority: WO
Inventors: Ralf Christoph; Detlef Ferger
Original assignee: Werth Messtechnik Gmbh
Priority date: 2012-10-05
Filing date: 2013-10-02
Publication date: 2014-04-10
Also published as: DE102013108457A1; DE112013004895A5

Abstract

The invention relates to a method and a device for incident illumination and/or transillumination of an object (5) by means of an illumination source (2), wherein the light exiting from the illumination source can be coupled into the beam path of an optical sensor (4) and imaged onto the object, or the illumination source is arranged on the side of the object facing away from the optical sensor. In order to allow quick switching between different types of illumination such as bright field direct illumination, dark field direct illumination, various angles of inclination and directions, and transillumination with simple means, according to the invention the illumination source (2) is a planar illumination source and the illumination source comprises at least one plurality of lighting elements (6), which can be switched independently of one another.

Description

Method and device for illuminating and measuring an object

The invention relates to a method and to a device for incident illumination and / or transmitted light illumination of an object by means of a lighting source.

In particular, the invention relates to a device for incident illumination and / or transmitted light illumination of an object by means of an illumination source, wherein the radiation emanating from the illumination source in the beam path of an optical sensor, preferably image processing sensor, coupled and imaged onto the object or a method for reflected illumination and / or transmitted light illumination of an object by means of an illumination source, wherein the radiation emanating from the illumination source is coupled into the beam path of an optical sensor, preferably image processing sensor, and imaged onto the object.

The invention also relates to a device and a method for incident illumination and / or transmitted illumination of an object by means of an illumination source, wherein depending on the position of the optical sensor, only a limited area of the illumination source is driven, preferably a range within a predetermined angular range to the optical axis of the optical sensor.

A change in position of an optical sensor is present in particular when used in a coordinate measuring machine. The invention therefore preferably relates to the use of the illumination according to the invention in a coordinate measuring machine.

An embodiment of the invention relates to incident light illumination, in which a mark is projected onto the object surface in at least one working distance of an optics used with a variable working distance.

Areal trained lighting sources are already used in many areas of optics and metrology, for example, for the transmitted light illumination or incident illumination of samples. However, only luminous fields are consistently found here Use that provide the most homogeneous possible illumination and in which the brightness for all areas of the illumination source is changed together. This is to achieve a uniform illumination. These illuminations are used in particular in the field of coordinate metrology with optical sensors.

However, this has the disadvantage that there is always a mixture of different beam directions, in the case of epi-illumination so there is a mixture between bright field illumination and dark field illumination. For metrological purposes, especially in dimensional measurement, such as in coordinate metrology, this results in a reduced contrast and deteriorated measurement results, for example, in edge detection in the context of image processing or the determination of points on the surface of the object. These effects are particularly clear when no further optical elements such as lenses or the like are passed through by the illumination, ie the illumination is directed only by lateral mirroring onto the object to be measured, as is done in some microscopes.

To increase the contrast, mechanical diaphragms are used in the prior art, in particular in microscopy. These are limited in their switching speed, wear out and are quite inflexible. In addition, this can only restrict the diameter, but not realize a defined lighting.

Also disadvantageous is the relatively large radiation angle of the individual light-emitting elements which are known in the art in the field of LEDs or laser diodes or similar light sources. As a result, beams reach the optical sensor, in particular the area covered by the aperture of the front lens, which occupy a large angle to the optical axis of the sensor, whereby edges or structures of the measurement object are displayed obliquely and thus appear laterally displaced, for example on the planar matrix of a camera chip image processing sensor. This results in aberrations, in particular in the case of high measurement objects, ie objects with an extension in the direction of the imaging axis of the optical sensor, in particular in the case of expansions in the order of magnitude of the depth of field of the optics and beyond. To avoid this and to produce an almost parallel to the imaging direction extending, also called telecentric illumination, optical Elements used for collimation or tubular aperture arrays. The collimation by means of a lens has the disadvantage that it must be arranged almost centrally to the beam path of the optical sensor and thus moved with the sensor. In addition to the increased expense of additional drives and guide devices, there is a risk of collision with the measurement object or it may be structurally complex protective measures taken. In addition, the size and in particular the distance between the illumination and the sensor, whereby the luminous efficacy decreases. The latter also applies to tubular diaphragm arrays, as can be seen from EP 1 618 349 A1. In addition, it is disadvantageous that the diameter of the tubes must not fall below a minimum value, so that a sufficient amount of light can happen. This results in a structure which, depending on the optics used by the sensor, can be visible and adversely affects the image quality. In addition, precisely manufactured tubular diaphragm arrays are expensive. However, if a similar effect of the telecentric illumination or the limitation of the emission angle of the lighting elements contributing to the lighting can be carried out without additional measures such as lenses or tubular diaphragm arrays, conventionally available and inexpensive planar light-emitting element arrays can be used, as described, for example, in the TV technology Names LCD or LED array are known. It is also possible to use LCoS (Liquid Crystal on Silicon) or OLED display arrays (organic light emitting diodes).

From the reference: Christoph et al., Multisensor Coordinate Metrology, The Library of Technology, Volume 248, Verlag Moderne Industrie, 2003, are shown on page 23 types of illumination. In the bright field incident light, a point-shaped light source is coupled into the beam path of the camera. Coupling means that at least sections of the beam path of the coupled light source and the camera coincide partially.

When dark field incident light, a lighting arrangement can be used, as can be found in EP 1 373 827 Bl. Light sources are arranged on concentrically arranged circles whose beam paths intersect the optical axis of the camera. There is thus no at least partially common course. Coupling therefore does not take place. In addition, it is an arrangement of individual point-shaped light sources, which are arranged exclusively on rings, but which not form a coherent closed surface that passes through the optical axis. As a result, it is not possible with this illumination arrangement to enable a bright field epi-illumination. In addition, only the discreetly provided illumination angle are possible for a dark field incident light illumination, which are predetermined by the spatial orientation of the point-shaped light sources, so no free adjustment of the angle of inclination of the lighting possible.

Object of the present invention is to provide a flexible lighting device and a method for operating the device available that allows fast and simple means, and almost wear-free switching between different types of illumination such as brightfield, darkfield light different inclination angles and directions and transmitted light, wherein the contrast present is as high as possible in order to allow accurate dimensional measurements in the entire measuring range or field of view of an optical sensor.

Another object of the invention is to increase the contrast of the illuminated object surface.

The invention is also intended to illuminate objects which are to be subjected to a dimensional investigation, for example by determining edges or surface points. Corresponding objects are usually larger than the area that can be detected by an optical sensor, such as the image processing sensor, in particular if it is provided with a magnifying imaging objective in order to achieve high accuracies. In order nevertheless to detect the entire object or the entire object contour like outer edges, the sensor and the object are brought into different positions relative to one another and respectively partial contours are determined and possibly combined to form an overall contour. When determining the partial contours, it is provided according to the invention to illuminate only the area detected by the sensor in such a way that an accurate measurement is realized. This is done according fiction, in that the angle of incidence of illumination with respect to the edge position on the object or the optical axis of the sensor is limited to achieve a sharp image of the object edges. For this purpose, only selected areas of the illumination source are switched on in each case. A particular independent task is to limit the maximum angle of incidence of the illumination with respect to the optical axis of the optical sensor, yet a flat trained light source is to be used, which has a higher extent than that without movement of the optical sensor detectable from this area ,

To achieve one or more aspects of the invention, u. a. provided that the illumination source is a flat formed illumination source and that the illumination source consists of a plurality of light elements which are independently switchable, in particular switched on and off or in their intensity are adjustable.

The illumination source, which in the actual sense represents an illumination field, is formed by luminous elements which are arranged relative to one another such that a luminous field with preferably between 100 and 10,000 luminous elements per cm, preferably between 100 and 5,000 luminous elements per cm. The illumination source, so the illumination field can be an areal extent of z. B. 1 mm x 1 mm to z. B. 600 mm x 600 mm. In particular, in the realization of the teaching of the invention in a transmitted light illumination, a planar extension can be provided, which corresponds to the measuring range of a coordinate measuring machine in the XY measuring plane.

In particular, to form the planar illumination source two-dimensional LCD matrices (liquid crystal display), LED matrices (Light Emitting Diode), OLED matrices (Organic Light Emitting Diode), LCoS matrices (Liquid Crystal on Silicon) or fiber bundles, more precisely so-called ordered fiber bundles, used, whose elements are individually controlled.

Flat includes in particular a circular, rectangular or oval shape, within which the light elements are arranged to form the surface. The term light element also includes micromirrors, wherein a micromirror array forming a surface is an areally formed illumination source.

Although planar illumination sources for the projection of lines or patterns are known, which are focused in the object plane. The shape of the projected patterns is then detected by an optical sensor and provides information about the surface shape of the object. In order to achieve accurate measurement results, the so-called structured light must be sharply imaged in the object plane. It is therefore not an incident illumination in the sense of this invention, which would be suitable to illuminate a portion of an object completely and the direct evaluation, for example, by image processing, accessible. Rather, in this type of sensor, the object is measured indirectly, for example by triangulation, ie direction determination, and only at the points at which lines of the pattern are imaged. The design of the structured illumination is usually done by fixed apertures in the form of masks, deflection of a light beam by rotating polygon mirror or modulation of the intensity of a point or surface light source.

In contrast, in one embodiment of the present invention, however, the position of the projected patterns is not evaluated, but a parameter dependent on the focusing, ie the distance between sensor and object surface and thus the topography of the surface, such as the sharpness of the imaged pattern. It is determined, so to speak, which areas of the pattern are sharply imaged, for example by the intensity in the center of the respective areas of the pattern is determined, which are turned on, that is illuminated. If there is a focus in this area, the center is bright and the area around the center is darker. Outside the focused state, a brightened area forms around the center and the center itself is also darker than in the focused state. On the basis of the intensity in the center of the individual areas illuminated by the pattern, it is possible according to the invention to determine the focusing state and thus the distance to the object and thus therefore each illuminated area by recording the intensity at different distances between the sensor and the object. So that the bright areas of the pattern do not influence one another, ie, that the blurred image of the adjacent bright area is overspread, the bright areas of the pattern are spaced apart and rather small in their diameter, e.g. B. only a few or even one pixel in size. Alternatively, the contrast in the area of the center and around it can be determined. This becomes maximum similar to the intensity in the focused state. The simplest form of a pattern is that each illuminated measuring point is surrounded in all directions by exactly one unilluminated measuring point, ie in each case alternately lighting one measuring point in two directions and the next one being unlit. As a result, a quarter of all measuring points can be determined in one measuring cycle. In the next three bars, the pattern is shifted in the first, then the second and finally in both directions, illuminating previously unlit measuring points and not illuminating the previously lit ones. Under certain circumstances, larger distances between the illuminated measuring points are possible, so it is a greater distance in the pattern needed. There are then more than four measurements with the respective shifted pattern necessary to capture all measurement points. The respective shifted patterns are referred to below as different patterns. The different patterns are each shifted as often to each other or varied so many times until all sections were illuminated at least once within the surface illuminated by the pattern.

It is additionally provided that one or more of the partial regions used for the measurement, for example in the form of the patterns, of the light source are driven at a plurality of differing distances between the sensor system and the measurement object surface, wherein an overall image is preferably composed of the partial images per distance or distance region, and the distance between the sensor system and the measurement object surface per sub-area is determined by taking into account at least the position of the respective sub-image for which the respective sub-area such as pixel has the highest intensity or brightness.

In a further refinement, reflected-light illumination, in particular bright-field illumination, is produced with increased contrast by projecting a mark on the object surface. For this purpose, a mask, such as chromium mask, with translucent glass regions and opaque chromium regions is arranged in the beam path of the reflected light illumination source before being reflected in the beam path of the optical sensor. By means of an optics which are likewise arranged in front of the reflection and / or optics arranged after the reflection, the mark is focused into an intermediate image plane. This intermediate image plane or an image plane generated by means of a further optical system, in which the mark is sharply imaged, is, according to the invention, in at least one setting for the optical sensor used and detected by the Auflichtbeleuchtungsstrahlengang at least partially traversed optics from the optical sensor. As a result, an increased contrast is artificially generated in the focal plane of the optical sensor, as a result of which the focusing method according to the invention provides improved results, in particular for object surfaces with a low structure. In order to enable bright-field illumination even without effective brand projection, it is provided that the mark is imaged blurred in at least one modified working distance of the optics of the optical sensor in the then existing focal plane. This is achieved by adjusting at least one optical lens of the optics of the optical sensor, which is not traversed by incident light illumination beam path and thus the adjustment of the working distance has no influence on the position of the plane in which the pattern is sharply imaged. This embodiment can also be combined according to the invention with the idea that the illumination source consists of a multiplicity of luminous elements which can be switched independently of one another. The illumination source itself may represent the mark by turning on only selected lighting elements.

In a further inventive concept, the individual elements emit different wavelengths, ie colors. For this purpose, corresponding matrices or fiber bundles are used, in which the individual elements discrete wavelengths are assigned, for example in the form of a Bayer pattern, as is also known in color cameras. Since all available colors are available over the entire surface, the colors can be varied in all areas. This makes it possible, as described later, set the color separately for the different types of lighting already mentioned.

Alternatively, micromirror arrays are used, the individual elements being mirrors which can be controlled in their orientation or direction or angle. This reflects the light from a light source directed at the array at a first or second angle, depending on the orientation of each individual mirror. As a result, it is either directed into a so-called light trap or emitted in a defined direction. The principle is used for example in DLP beamers (Digital Light Processing). The two adjustable angles can also be selected, or the array can be aligned to the light source so that the two angles are used for two different types of illumination. Thus, for example, at the first tilt angle a parallel Lighting for a transmitted light illumination realize and by the second tilt angle a Auflichtart.

According to the invention, the individual light elements or micro mirrors are subdivided into groups, with one or more groups being switchable independently of one another. A group can consist of only a single light element.

Content of the method according to the invention is the selection and the switching or

Set one or more groups of lighting elements to one

To achieve bright field incident lighting or a dark field incident lighting or a transmitted light illumination or a mixture of lighting types.

A self-invented method step consists in the illumination restricted specifically to one area, which is selected as a function of the position of a moving optical sensor with respect to the areal illumination in such a way that the maximum occurring angle between illumination and optical axis of the optical sensor is limited in order to reduce aberrations , This can be advantageously used for measurements in transmitted light, wherein the illumination is arranged on the side remote from the optical sensor side of the object to be measured and in each case only the area is turned on or adjusted, which is opposite to the optics. As a result, illumination beams are avoided with a large angle to the optical axis of the optical sensor. Likewise, the method can be used for incident light illumination, preferably for the illumination in the bright field, that is coaxial with the optical axis of the optical sensor. In this case, the illumination can be introduced via a deflection in the beam path or else be arranged directly in this. For example, transparent illumination sources such as OLEDs are suitable for this purpose.

The lighting is made possible by a single lighting device, which saves space and costs.

A further object of the invention is that surface points which contain positional information of the measurement points along the optical imaging direction are determined. For this purpose, the known brightness or contrast evaluation according to the focus technique, wherein the image recording in several distances between the sensor and Object is repeated. For lighting, however, to dispense with the complex construction of screens or rotating disks with holes such as Nipkov disks, as these are used in Konfokaltechnik, and instead the light source according to the invention is driven so that a pattern is shown that a produces similar image as the image produced by confocal apertures.

In particular, the object underlying the invention is essentially achieved by a device for incident illumination and / or transmitted light illumination of an object by means of a flat illumination source, the radiation emanating from the illumination source coupled into the beam path of an optical sensor, preferably image processing sensor, and coupled to the object is formed, wherein the illumination source is a flat formed illumination source and the illumination source is formed of at least a plurality of light elements, such as two-dimensional LCD matrix, LED matrix, OLED matrix, LCoS matrix, fiber bundles or at least one micromirror array, wherein the individual light-emitting elements or micromirrors can be switched independently of one another, preferably the light-emitting elements or micromirrors are subdivided into groups, one or more groups being able to be switched independently of one another.

The areally formed illumination source, which can be referred to as the illumination field, is formed in particular by an arrangement of luminous elements, with 100 to 10,000 luminous elements per cm, preferably 100 to 5,000

Luminous elements per cm for the formation of the surface are arranged in particular regularly. The total area of the areal trained illumination source can be z. B. dimensions between 1 mm x 1 mm to 600 mm x 600 mm. In particular, the areally formed illumination source, that is to say the luminous field, can also have a planar extent, which corresponds to the measuring range of a coordinate measuring machine in the XY plane.

A particular feature of the inventive device is that the radiation of the illumination source is not focused in the object plane, so no structured illumination takes place, as is the case with sensors based on the light projection such as triangulation sensors. A further independent solution of the object underlying the invention is achieved by a device for incident illumination and / or transmitted light illumination of an object by means of an illumination source, wherein the radiation emanating from the illumination source radiation in the beam path of an optical sensor, preferably image processing sensor, can be coupled and imaged on the object or the illumination source is arranged on the side of the object facing away from the optical sensor, wherein the illumination source comprises a multiplicity of luminous elements, which can be switched independently of one another depending on the position of the optical sensor.

Coupling means that the beam path of the illumination source coincides at least in sections with that of the optical sensor, at least in the region in which the beam path strikes the region or point of the object to be measured.

A particular feature of the inventive device is that only the lighting elements are switchable, which are arranged within a fixed angular range to the optical axis of the optical sensor, preferably the angular range by a definable angle of for example 1 ° or 3 ° or 5 ° greater than that the numerical aperture of the lens associated with the optical sensor resulting acceptance angle. Depending on the spatial direction, this angular range can be different. As a result, not only circular areas, but also otherwise shaped areas of the illumination can be switched, that is switched on or controllable, such as, for example, matched to the camera dimensions of the optical sensor rectangular areas.

In particular, it is provided that only the light-emitting elements can be switched on, in which the angle Phi between the optical axis of the sensor and the direction of the direct line connecting the light-emitting element and the optical sensor is <10 °, preferably <3 °, particularly preferably <1 °. The direct connecting line extends in particular between the center of the surface of the luminous element and the center of the object-side foremost optical element such as lens (also called front lens) of the optical sensor.

Preferably, it is provided that the optical sensor is movable at right angles or at least approximately at right angles to its imaging direction, and the optical sensor Lighting source has a greater extent than the detectable by the fixed optical sensor surface, preferably covering the entire detectable by the moving optical sensor area.

In particular, the invention is also characterized in that the illumination source is fixed and the optical sensor with respect to the illumination source in at least one direction is perpendicular or nearly perpendicular to its imaging direction movable, or that the illumination source in a first rectangular or nearly perpendicular to the imaging direction of optical sensor is movable and the optical sensor in a second, perpendicular or nearly perpendicular to the imaging direction of the optical sensor and at right angles or at right angles to the direction of movement of the illumination device extending direction is movable.

It is preferably provided that object and optical sensor are movable relative to one another in the direction of the imaging direction of the optical sensor and preferably at right angles or at right angles to the imaging direction of the optical sensor and the illumination source has an extension which detects at least the optical sensor fixed relative to the object Surface illuminated, and the illumination source is fixed relative to the optical sensor.

The movement in the direction of the imaging direction of the optical sensor, ie the optical axis, serves to carry out the already described focus method for the determination of surface points. Advantageously, the area covered by the sensor is illuminated by the illumination source. The movement perpendicular to the optical axis makes it possible to determine surface points at different points on the object.

In particular, the invention is characterized in that the luminous elements forming a surface are at least luminous elements from the group LCD matrix, LED matrix, OLED matrix, LCoS matrix, fiber bundles, at least one micromirror array. The light-emitting elements used are those from the group of two-dimensional LCD matrix, LED matrix, OLED matrix, LCoS matrix, fiber bundles or at least one micromirror array. It should also be emphasized that the radiation of the illumination source impinges unfocused on the object plane. This is intended to fiction, contemporary lighting, without limiting the invention so. In the case of the application of the focus method, however, a focus sation by means of a suitable optics.

Therefore, it is preferably also provided that the radiation of the illumination source can be focused into the focal plane of the optical sensor by means of an optical system which is connected to the optical sensor or is already contained in the optical sensor.

In particular, the invention is characterized in that a plurality of selected lighting elements of the illumination source are jointly controllable, which form a pattern, preferably several successive different patterns can be generated. As a result, the fiction, contemporary focus method for multiple surface points is possible simultaneously. It is provided, as already explained above, that the pattern in each case to illuminate not overlapping areas in the unfocused state.

Preferably, it is provided that the coupling with means for deflecting the radiation of the illumination source, such as deflecting mirror, splitter cube, splitter plate or pellicle, preferably using partially transmissive optical layers or wavelength-selective layers or vibration direction-selective layers.

In the simplest case, in the simplest case, particularly preferably, only a deflection of the radiation emitted by the planar illumination source takes place at the object-side end of the optical sensor, that is to say a coupling between the object and the side of the optical elements of the optical sensor facing the object.

The invention is also characterized in particular by the fact that the areally formed illumination source is arranged in such a device for incident illumination in such a way to the optical axis of the optical sensor, that a normal of the plane spanned by the planar illumination source normal to the optical axis of the optical sensor at an angle α with 70 ° <α <110 °, in particular α = 90 ° intersects. So then the outgoing of the lighting elements rays or the beam bundle generated by this, in particular runs parallel to the optical axis of the sensor, a corresponding optical deflection device is provided.

Regardless of this, the invention is characterized in that the areal trained illumination source, when all elements are turned on, forms a coherent, closed surface, which is traversed by the optical axis of the optical sensor after alignment as deflection on the object to be measured. In particular, it is provided that the planar illumination source, taking into account the required optical elements for coupling in the rays emanating from the illumination source along the optical axis, can be implemented centrally from the optical axis.

In the case of a bright field incident illumination, it is provided that a coherent, closed surface is penetrated by the optical axis of the sensor, the radiation of the luminous surface, which is deflected in the direction of the object, being essentially parallel and in the direction of the optical axis.

Corresponding designs and orientations also result when a micromirror array is used as a light field.

Alternatively, the device is characterized in that the coupling takes place between the optical elements of the optical sensor or between the optical elements and the image sensor of the optical sensor. In this case, the radiation of the illumination source thus passes through the optical elements such as lenses and / or diaphragms and / or splitter layers of the optical sensor.

In particular, the invention is characterized in that the transmitted light illumination is arranged on the opposite side of the optical sensor of the object and is preferably coupled without deflection. The illumination source is thus opposite the optical sensor and radiates in the opposite direction of the optical axis of the optical sensor. Preferably, the invention provides that between the illumination source and coupling an optical element such as lens and / or aperture and / or filter, the rays through smaller than a defined critical angle to the mean direction of the rays of the illumination source durchlas st, preferably formed by a plurality of arrangement in the radiation direction tubular or honeycomb-shaped and juxtaposed elements is arranged.

The optical elements such as lenses or diaphragms can be used to adapt the beam geometry of the illumination to the field of view of the sensor. By means of the filter, a parallelization of the radiation is carried out, preferably in the bright field Auflicht- or transmitted light illumination.

It is further to be emphasized that the illumination device is integrated in a coordinate measuring machine and the control of the illumination device and the optical sensor is connected to the control of the coordinate measuring machine, and preferably two illumination devices are used, which are arranged on opposite sides of the object, and preferably two optical sensors used, which are arranged on opposite sides of the object. Through these measures, the lighting fulfills all the tasks of the various types of illumination used in coordinate metrology. A second illumination device of the type mentioned above is required if only one sensor is present and should be realized for this incident illumination and transmitted light illumination. If these two illumination devices are present, however, a second sensor on the opposite side of the object can also be supplied with both types of illumination. This makes it possible to measure the object on both sides.

Preferably, it is provided that the plurality of light elements or fibers or micromirrors of the illumination source emit light of different wavelengths, preferably by using an RGB matrix illumination source.

In particular, the invention is characterized in that the lighting elements are arranged in a plane which is preferably parallel or perpendicular to the support surface of the object to be measured. Preferably, the invention provides that only the lighting elements are switched on, in which the angle Phi between the optical axis of the sensor and the direction of the direct line connecting the light-emitting element and the optical sensor <10 °, preferably <3 °, more preferably <1 ° ,

Eigenerfinderisch a device is characterized in that in an illumination beam path, preferably bright field illumination beam path, before being reflected in the beam path of an optical sensor, preferably image processing sensor with focus sensor function, a brand, such as chrome mask, is arranged with translucent and opaque areas in the focal plane an optics associated with the optical sensor with adjustable working distance in a first setting for the working is focused from focused and mapped in at least one other focal plane of a modified working distance, preferably by the optics contains at least one adjustable to adjust the working distance of the optic lens, which is traversed by the illumination beam path only after the reflection on the object, that is arranged between reflection and the receiver of the optical sensor, wherein the mark is preferably formed by the Variety of lighting elements of the illumination source, with only selected lighting elements are turned on.

One or more objects underlying the invention are essentially also achieved by a method for incident illumination and / or transmitted light illumination of an object by means of an illumination source, wherein the radiation emanating from the illumination source is coupled into the beam path of an optical sensor, preferably an image processing sensor, and onto the object is formed, wherein the illumination source is formed flat and the illumination source is formed at least from a plurality of light-emitting elements, such as two-dimensional LCD matrix, LED matrix, OLED matrix, LCoS matrix, fiber bundles or at least one micromirror array, wherein the individual light elements or micromirrors are switched on or set independently of one another, preferably the individual light-emitting elements or micromirrors are subdivided into groups, and the individual or a plurality of groups are switched on or set independently of one another to achieve a bright field incident lighting or a dark field incident lighting or a transmitted light illumination or a mixture of lighting types.

Another selffinderisch the task underlying the invention solving method consists in incident light illumination and / or transmitted light illumination of an object by means of an illumination source, wherein the illumination source is formed areal and emanating from the illumination source radiation in the beam path of an optical sensor, preferably image processing sensor, and is imaged on the object or the illumination source is arranged on the side facing away from the optical sensor side of the object, wherein the illumination source comprises a plurality of luminous elements, which are switched independently depending on the position of the optical sensor and / or adjusted such that a bright field incident illumination or a dark field incident illumination or a transmitted light illumination or a mixture of the illumination types is achieved.

A third selffinderisch the task underlying the invention solving method consists in a method for the determination of measuring points on the surface of an object with an optical sensor according to the focus principle, preferably confocal focus principle, consisting at least of a flat pronounced receiver or image sensor such as CCD or CMOS sensor having a plurality of photosensitive elements for taking two-dimensional images, using incident light illumination, wherein the radiation emanating from the illumination source is coupled into the beam path of the optical sensor and imaged onto the object, and wherein a parameter characteristic of the surface of the object how the contrast value and / or intensity value is determined in a plurality of relative positions between object surface and focal plane of the sensor varying in the direction of the optical axis of the optical sensor by taking two-dimensional images, and from the Rela and the characteristic parameter, the coordinate of at least one measuring point present along the optical axis is determined, wherein the measuring range determined by the images perpendicular to the optical axis is subdivided into partial regions, wherein the illumination source is flat and is formed from a plurality of luminous elements controlled independently of each other, that is switched on and / or adjusted, the respective triggered lighting elements form patterns that illuminate each selected sub-areas.

In particular, the invention is characterized in that the radiation emanating from the illumination source is focused into the focal plane of the optical sensor, preferably by an optics connected to the optical sensor or already contained in the optical sensor, and preferably the illumination source is fixed relative to the optical sensor.

It is preferably proposed that the partial regions are assigned to individual pixels or groups of adjacent pixels of the receiver of the optical sensor

It should be emphasized that the respective plurality of partial regions illuminated by the respective pattern in the focused state are spaced from one another, preferably at a distance from one another which is at least twice, preferably at least 5 times, particularly preferably at least 10 times the side length of Subarea corresponds, preferably so that during the relative movement no superposition of the plurality of illuminated subregions takes place due to the occurring defocusing of the pattern.

Furthermore, the invention is distinguished by the fact that the respective plurality of partial regions illuminated by the respective pattern are spaced apart from one another such that during the relative movement no superimposition of the several illuminated partial regions occurs due to the defocusing of the pattern occurring.

The invention is also distinguished by the fact that the characteristic parameters and the resulting coordinate during the variation of the relative position between the object surface and focal plane of the sensor are determined simultaneously or substantially simultaneously for the subregions illuminated by the respective pattern, the perpendicular to the optical axis present coordinate is determined from the present perpendicular to the optical axis position of the sub-area in the image and the optical sensor relative to the object. In particular, the invention is distinguished by the fact that for each distance or distance range, an overall picture is composed of the sub-images assigned to the sub-areas, and the distance between the optical sensor and the measuring object surface per sub-area is determined by taking into account at least the position of the respective sub-image the respective subarea such as pixels has the highest contrast or the highest intensity or brightness.

According to a particularly noteworthy proposal, it is provided that relative movements are carried out several times in succession when using different patterns or during a single relative movement different patterns are repeatedly set in several cycles, wherein each pattern several measurement points are determined, each selected sub-areas corresponding to the respective Pattern are set.

In particular, the invention is characterized in that the different patterns are each shifted to each other as often or are varied so often until all sections have been illuminated at least once.

In particular, the invention is characterized in that only the lighting elements are switched on or adjusted, which are arranged within a predetermined angular range to the optical axis of the optical sensor, preferably the angular range is greater by a definable angle of for example 1 ° or 3 ° or 5 ° as the acceptance angle resulting from the numerical aperture of the lens associated with the optical sensor.

It is preferably proposed that only the lighting elements are switched on, in which the angle Phi between the optical axis of the sensor and the direction of the direct connecting line between the light-emitting element and the optical sensor is <10 °, preferably <3 °, particularly preferably <1 °. The direct connecting line extends in particular between the center of the surface of the luminous element and the center of the object-side foremost optical element such as lens (also called front lens) of the optical sensor. Particularly noteworthy is that for measuring one or more features of the object, the optical sensor is moved at least perpendicular or almost perpendicular to its imaging direction and the illumination source has a greater extent than the detectable by the fixed optical sensor surface, preferably the entire detected by the moving optical sensor Area covers.

Furthermore, the invention is characterized in that the illumination source is fixed and for measuring one or more features of the object the optical sensor is moved with respect to the illumination source in at least one direction perpendicular or nearly perpendicular to its imaging direction, or that for measuring one or more a plurality of features of the object, the illumination source is moved in a first direction perpendicular or substantially perpendicular to the imaging direction of the optical sensor and the optical sensor in a second, perpendicular or nearly perpendicular to the imaging direction of the optical sensor and at right angles or at right angles to the direction of movement of the illumination device extending direction is moved.

The invention is also characterized in that light elements in the middle of the illumination source are grouped to produce the bright field incident illumination, preferably circularly adjacent illumination elements. As a result, only near-axis beams with a small angle to the propagation direction of the illumination radiation reach the object and form a so-called bright field incident illumination.

In particular, the invention is characterized in that for generating the dark field incident lighting lighting elements are grouped outside the center of the illumination source, preferably in the form of circular rings, preferably a plurality of radially offset annuli are switchable to achieve different illumination angle of the dark field illumination, and preferably along the annuli the periphery are divided into segments to achieve different directions of the dark field illumination. In this case, only off-axis beams with a larger angle to the propagation direction of the illumination radiation arrive at the object and form a so-called dark field incident illumination. According to a particularly noteworthy proposal, it is envisaged that to generate the transmitted light illumination, all the illumination elements of the illumination source are preferably used, with micromirrors preferably being used whose directions are adjusted to produce parallel light, or the micromirrors are grouped to produce diffuse light and adjusted in different directions. As a result, the two known in transmitted light illumination beam characteristics, namely parallel or diffused light, achieved.

Alternatively, according to the invention, parallel transmitted light can also be generated without a tilting mirror by introducing a filter between an illumination source and the coupling, since the filter transmits only beams smaller than a defined critical angle to the mean direction of the beams of the illumination source, preferably formed by an arrangement of a plurality in the direction of radiation honeycomb-shaped and juxtaposed elements.

Particularly noteworthy is that the directions of the micromirrors are changed in each case at least one group for switching between the on state and off state of the respective type of illumination or to switch between bright field and dark field illumination.

Furthermore, the invention is characterized in that transmitted light illumination and bright field illumination and / or dark field illumination is achieved by a single illumination source and two optical sensors, which are arranged on opposite sides of the object, are used to measure the object from two sides.

The invention is also characterized in particular by the fact that the color of the transmitted light illumination and / or incident light illumination is set by controlling the corresponding light elements, with different colors preferably being set for the types of illumination or the different dark field circles or segments.

Preferably, it is provided that the method is used in a coordinate measuring machine. According to a proposal to be particularly emphasized, it is provided that the lighting elements to be switched on are determined according to a preliminary measurement of the object contours or the object boundary with the optical sensor, preferably in different relative positions between sensor and object, wherein in the pre-measurement all the lighting elements of the respectively selected illumination type transmitted light or Incident light or at least the part of the luminous element which is necessary for a complete illumination of the object, are switched on and the contours or the boundary of the object roughly determined in their position, and then depending on the relative position between sensor and object only the light elements are turned on, contribute to the illumination of the detected by the sensor, roughly determined contour under the predetermined maximum angle Phi.

A selffinderisches method provides that to increase the contrast of the detected by an optical sensor surface of an object in an illumination beam path, preferably bright field illumination beam path, before the reflection in the beam path of an optical sensor, preferably image processing sensor with focus sensor function, a brand, such as chrome mask, with light-transmissive and opaque areas is arranged and is focused by adjusting a first working distance of the optical sensor associated optics with adjustable working distance in the focal plane of the optics, wherein the mark is blurred in at least one other focal plane of a modified working distance, preferably by the optics at least contains an adjustable lens for adjusting the working distance of the lens, which is traversed by the illumination beam path only after the reflection on the object, ie between reflection and the receiver it is arranged of the optical sensor, wherein preferably the mark is formed by only selected light elements are turned on from the plurality of light elements of the illumination source.

Further details, advantages and features of the invention will become apparent not only from the claims, the features to be taken from them - alone and / or in combination - but also from the following description of the figures.

Show it: Fig. 1 shows a first preferred embodiment of a fiction, contemporary

Device with coupling of the illumination between the optical sensor and the measurement object,

Fig. 2 shows an extension of the first preferred embodiment by a

Imaging optics and / or aperture,

Fig. 3 shows an extension of the first preferred embodiment by a

Arrangement for limiting the emission angle,

Fig. 4 shows a second embodiment of a device according to the invention with

Coupling of the illumination within the beam path of the optical sensor and a second optical sensor with coupling of the illumination between the second optical sensor and the test object,

Fig. 5 shows the application of the inventive method for the production of

Hellfeldauflicht,

Fig. 6 shows the application of the inventive method for producing a first

Dark eldauflicht,

Fig. 7 shows the application of the inventive method for producing a second

Dark field light of different inclination,

Fig. 8 shows the application of the inventive method for producing a

Dunkelfeldauflicht segment,

Fig. 9 shows the application of the inventive method for the production of

By light

10 shows an alternative arrangement for generating bright field illumination under

Use of a tilting mirror array, 11 shows an alternative arrangement for producing dark field incident light below

Use of a tilting mirror array,

Fig. 12 shows an alternative arrangement for generating transmitted light below

Use of a tilting mirror array in the off state,

Fig. 13 shows an alternative arrangement for generating transmitted light below

Use of a tilting mirror array in the switched-on state,

14 shows a further alternative method using a further arrangement according to the invention,

Fig. 15 is a particularly emphasized method using the inventive arrangement and

Fig. 16 is a particularly emphasized method using different patterns.

A first preferred embodiment of a device according to the invention with coupling in of the radiation of an illumination 1 consisting of areally illuminated source 2 and deflection device 3 between optical sensor 4 and object or measuring object 5 will be explained with reference to FIG. The illumination source 2 according to the invention consists of individually controllable elements 6, of which three are marked by way of example in the figure. These elements 6 can be switched on and off separately, as well as their intensity control. The number of elements 6 is several hundred to several thousand elements 6 in both propagation directions. For example, two-dimensional LCD matrices (Liquid Crystal Display), LED matrices (Light Emitting Diode), OLED matrices (Organic Light Emitting Diode), LCoS matrices (Liquid Crystal on Silicon) or ordered fiber bundles are suitable for this purpose. The individual elements 6 emit white light. Alternatively, colored radiating elements 6 are used.

For a lighting source that forms a square surface, the edge lengths between 1 mm and z. B. 600 mm. The number of light elements per cm can be between 100 and 10,000, in particular between 100 and 5,000. The radiation emitted diffusely but in the middle in the direction of an arrow 7 of the illumination source 2 is directed via a partially transparent mirror 3 in principle in the direction of the optical axis, characterized by an arrow 8, of the optical sensor 4 on the measuring object 5. Depending on which of the elements 6 are switched on, this produces brightfield or darkfield incident light illumination of the object 5. Between brightfield incident light and various dark field illuminations, as explained in FIGS. 6 to 8, it is possible to flexibly switch over by controlling the corresponding elements 6. A mixture of different types of lighting is thus possible.

As can be seen from the graphic representation, the invention may also be distinguished by the fact that the planar illumination source 2 spans a plane with a normal which intersects the optical axis 8 in particular perpendicularly or almost perpendicularly.

After the reflection of the radiation of the illumination source 2 on the measurement object 5, it is detected and evaluated by the partially transmissive mirror 3 by the optical sensor 4. The optical sensor 4 comprises at least one or more imaging lenses 9 and a detector 10, usually a planar CCD or CMOS camera matrix. The optical sensor 4 is preferably an image processing sensor which detects a planar region of the measurement object 5 in order to localize edges and / or surface points and assign them to these coordinates.

In addition, to generate transmitted light for the optical sensor 4, a further illumination source 2a can be arranged below the measurement object 5 resting on a transparent measuring table 11. If the radiation runs along the arrow 7a as indicated in FIG. 4 and the radiation is coupled in by means of a deflection device 3a, the illumination source 2a also acts as incident illumination for a second optical sensor 4a arranged below the measurement object 5 (FIG. 4). The illumination source 2 shown in Figure 1 acts for this second optical sensor 4a, as well as the alternative illumination source 2b of Figure 4, as transmitted light illumination. The measuring object 5 can be observed and measured with the arrangement shown in Figure 4 from two opposite directions, wherein for both directions Incident light and transmitted light can be used. In that regard, the figures are self-explanatory. This also applies to the other drawings.

FIG. 2 shows a possible extension of the coupling of the radiation of the illumination source 2 through a lens 12. This makes it possible to adapt the size of the irradiated surface of the measurement object 5 to the field of view of the optical sensor. A focusing of the radiation in the object plane, ie the plane of the surface of the measurement object 5, as in sensors with structured illumination, does not take place because the measurement object 5 should be illuminated as uniformly as possible in order to enable location-independent image processing. In addition, the image field can still be limited by aperture. In addition to the frame 13 of the lens 12, apertures 14 and / or 15 are arranged in front of or behind the lens 12. An optical sensor 4 or 4a has not been shown for the sake of simplicity.

FIG. 3 shows a further possible extension of the coupling of the radiation of the illumination source 2 into the optical axis 8 through an arrangement 16 for limiting the emission angle. The arrangement 16 represents a filter which, by means of tubular or honeycomb-shaped and juxtaposed, transparent elements such as openings 17 in the radiation direction 7, effects a parallelization of the radiation since, depending on the diameter and the length of the openings, only radiation will pass up to a certain boundary wave can. This is useful, for example, when used together with the illumination source 2 as bright field incident light or in conjunction with the illumination source 2a as transmitted light illumination according to FIG.

A second embodiment of the device according to the invention with coupling of the radiation of the illumination source 2b into the beam path of the optical sensor 4 will be shown with reference to FIG. For this purpose, an opening 18 is provided laterally of the optical sensor 4, through which the radiation in the direction of arrow 7 transverse to the optical axis 8b of the sensor 4 on the deflection 3b meets and in the direction of arrow 8b, ie in the direction of the optical axis to the measurement object. 5 is diverted. The deflecting device 3b, again a partially transmissive mirror, is arranged between the lenses 9 and the receiver 10 of the sensor 4. The radiation of the illumination source 2b thus passes through the lenses 9 of the optical sensor 4, wherein the Distance between the lenses 9 and the illumination source 2b is chosen so that in turn no focusing of the radiation on the measuring object 5 takes place.

In addition, FIG. 4 shows the already mentioned second optical sensor 4 a, which can be arranged opposite the optical sensor 4 on the opposite side of the object 5. The coupling takes place analogously to the optical sensor 4 in Figure 1 between the sensor and the object to be measured.

FIG. 5 shows the use of the inventive method for generating bright field incident light. For this purpose, only a central area, for example in the form of a circular area 19 is used for illumination, so only the elements located within the hatched area 19 shown hatched and turned on. The illumination source is shown in plan view. As a result, only with respect to the axis of the optical sensor 4 near-axis rays reach the measurement object 5, whereby a bright field illumination is achieved.

In contrast, FIGS. 6 to 8 show different dark-field incident light illuminations. In FIG. 6, only the elements of the illumination source 2 within the circular ring 20 are switched on for this purpose. Irrespective of this, the circular ring 20 is part of the areally formed illumination source 2. This results in a dark field incident illumination with a relatively steep angle of incidence of the radiation on the measurement object 5. If a further outward circular ring 21, as shown in Figure 7, turned on, a flatter dark field illumination is achieved , In order to illuminate directed structures with particularly high contrast, a certain direction of the darkfield incident illumination may be necessary.

This is achieved by switching on a segment of a circular ring. By way of example, the segment 22 of the circular ring 20 is switched on in FIG.

To mix bright field and dark field incident light illumination, the corresponding areas 19 to 21 are switched on together.

Figure 9 shows the application of the inventive method for generating transmitted light. For this purpose, preferably all elements of the illumination source are turned on. Depending on the optical magnification of the optical sensor 4 used, only the elements in the field of view of the optical sensor are switched on.

The flat illumination sources 2 shown in FIGS. 5 to 9 can emit colored radiation in addition to white. For this purpose, the elements have different colors, as is implemented for example in RGB matrices in the form of Bayer patterns. Thus, you can switch between the different colors and, for example, bright field and dark field can be realized with different colors. It is also possible with such matrices to set different colors for individual elements or areas of elements at the same time, that is, for example, to simultaneously realize a bright field illumination of a first color and a dark field illumination of a second color.

An alternative illumination source for generating bright field incident light is shown in FIG. In this case, a tilting mirror array 23, that is to say a multiplicity of tiltable micromirrors 24a or 24b, which are arranged two-dimensionally, and an additional light source 25 are used. The illustration in Figure 10 shows a simplified view from the side. 24a is an example of a non-tilted micromirror denotes, with 24b a micromirror in the tilted state. The micromirrors can be individually tilted electronically. The light emitted by the light source 25 in the direction of the arrows 26 is coupled depending on the tilted position of the micromirrors either in the direction of arrow 7 in the beam path (optical axis 8) of the optical sensor and along the beam path and by means of the deflection device 3 on the measurement object. 5 directed, or directed in the direction of arrow 7a to a so-called light trap 27. If only the micromirrors 24b are tilted in the center of the tilting mirror array 23, only objects near the axis reach the measuring object 5 and a bright field illumination ensues.

The same arrangement is shown in FIG. Here, however, only eccentrically arranged micromirrors are tilted, as a result of which only off-axis beams reach the measurement object 5 and form a dark field incident illumination. According to FIGS. 6 to 8, by selecting the tilted regions, different steep or flat angles of incidence of the radiation and direction-dependent illumination can be achieved. The Kippspiegelarray can also be used for transmitted light illumination, as shown in Figures 12 and 13. In the non-tilted state of the micromirrors, as shown in FIG. 12, the radiation of the light source 25 is directed onto the light trap 27 in the direction of the arrow 7a. If, however, the micromirrors are all set in the tilted state, as shown in FIG. 13, the radiation in the direction of the arrow 7 is reflected onto the measurement object 5 and a transmitted light illumination results.

FIG. 14 shows a further arrangement according to the invention similar to the arrangement of FIG. 1, but without the need for a deflection, without this resulting in a limitation of the teaching according to the invention. The arrangement consists at least of the areally executed illumination source 2a, consisting of a plurality of luminous elements 6, the measurement object 5 and the optical sensor 4 in two exemplary positions 4-1 and 4-2. The individual light-emitting elements 6 are separately switchable or adjustable, ie separately switched on and off, as well as controllable in intensity and represent a transmitted light.

The direction of the image is chosen arbitrarily and can just as easily be the other way round, so that the illumination source 2a is located above and the optical sensor 4 below the measurement object 5. Likewise, a lateral arrangement of the three components 2 a, 4 and 5 is possible.

With this arrangement, another alternative method can be used. Here, depending on the position of the optical sensor 4, wherein only the two positions 4-1 and 4-2 are shown here by way of example, only the light-emitting elements 6 in a predetermined range, here exemplarily the ranges 2-1 and 2-2, used for lighting, which are shown hatched in the figure. Each further position of the optical sensor 4 is assigned corresponding areas of the areally formed illumination source 2, which are each arranged only up to a maximum angle to the optical axis 8 of the optical sensor 4. As an example for the position 4-1, this area is characterized by the maximum angle Phi for a spatial direction. The angle Phi, which should amount to a maximum of 10 °, more preferably a maximum of 3 ° or a maximum of 1 °, includes the optical axis 8 of the sensor 4 and the direction of the direct connecting line between the luminous element 6 and the sensor 4. The corresponding straight line is marked 6 'in FIG. It runs between the middle of the surface of the Luminous element and the center of the object side foremost optical element, the front lens 9, the optical sensor 4. In a special way, the angle Phi is set according to the present at the respective optical sensor 4 numerical aperture. Preferably, Phi is chosen by a safety margin of, for example, 1 ° or 3 ° or 5 ° greater than the angle resulting from the numerical aperture, also called the acceptance angle. The numerical aperture of the sensors 4 used is, for example, 0.1 to 0.5, so that an acceptance angle to the optical axis of about 6 ° to 30 ° results.

FIG. 15 shows an inventive method which should be particularly emphasized, in which initially illumination with the arrangement according to the invention, for example according to FIG. 14, is controlled in such a way that all controllable elements 6, the illumination source 2 a are switched on and a pre-measurement with the optical sensor 4 in transmitted light , as shown here, or in reflected light. If the position and dimension of the measurement object 5 are known, a restricted area of the controllable elements 6, which completely illuminates the measurement object 5, can be switched on. By the pre-measurement, the rough determination of the position of the contours on the measurement object 5 with the optical sensor 4, preferably in several relative positions between sensor 4 and object 5, as shown in Figure 14 by way of example for two relative positions. In FIG. 15, the ascertained contour is shown in dashed lines and identified by the reference numeral 28. This determination is initially coarse, so the position of the contours so not exactly because light from relatively large angles to the optical axis for laterally shifted edge locations or a blurred image provides, as already explained above, especially on high objects under test in transmitted light. The roughly determined position of the edges or contour 28 is now used for targeted illumination for the actual, accurate measurement. According to the teaching of the invention, only the controllable elements 6 are switched on for this second measurement per relative position between sensor 4 and object 5, which contribute to illuminate the roughly determined edge locations respectively detected by sensor 4 along contour 28 at the predefinable maximum angle Phi. The corresponding regions of the controllable elements 6 are designated by 29. This procedure leads, in particular when using low magnification objectives, to improved determination of the position of the object contours. The angle Phi fiction, according to the numerical aperture plus a security surcharge can be selected. This is exemplary in one dimension by the Dashed lines 30 and 31 indicated, with a security surcharge was not considered.

In FIGS. 16 a to d, the different patterns are shown by way of example, which are set one after the other in order to illuminate the entire area of the object 5 piece by piece on the surface of the object 5.

With 32 are turned on light elements 6 and 33 switched off light elements 6 numbered. Two switched-on elements are always separated from each other by at least one switched-off element. This is necessary in order that the individual surface points, which can be calculated from them, can be determined separately from the correspondingly illuminated regions of the receiver 10, without being influenced by the adjacent regions illuminated by the activated luminous elements. The receiver 10 consists of a plurality of photosensitive elements, which are individually readable. On the other hand, the receiver elements surrounding the respective areas illuminated by the pattern must not be read in order to not use the light reflected by the measurement object 5 for the purpose of evaluation. The receiver 10 is therefore read out by means of a corresponding pattern which fundamentally corresponds to the illumination pattern. Thus, in each case only the receiver elements which are assigned to the regions of the light source which are illuminated in accordance with the currently set pattern are read out. In order nevertheless to detect all measuring points, the patterns shown in FIGS. 9a to 9d are used in succession. Under certain circumstances, it makes sense to maintain larger distances between the illuminated elements 32 in order to achieve a better separation. The number of patterns then increases accordingly. The illumination and readout of the corresponding subareas must each run synchronously. For this purpose, the camera 10 used for reading out the image and the light source 2 used for illumination are activated, for example, with known trigger functions or lines. The assignment of the lighting elements 6 to the receiver elements can, for example, be carried out in advance experimentally, ie by measuring.

The respective illuminated areas of the object 5 are thus imaged on the receiver 10 and thereby the respectively illuminated partial areas and possibly additionally the directly surrounding areas, of the receiver 10 to determine the multiple surface points. Thereafter, the next pattern is set to determine the next surface points. For each pattern, the distance between sensor 4 and object 5 is varied in order to determine the position of the highest intensity or the highest contrast, and thus the distance of the respective surface point to the sensor 4, by means of a focus method. So that the change in distance does not have to be repeated, it is preferably provided to switch the patterns alternately during the change of state.

reference numeral

1 lighting 11 measuring table

2 flat trained 12 lens

Illumination source 13 Version

2a flat 14 aperture

Illumination source 15 aperture

2b areal trained 16 arrangement

Illumination source 17 opening

2-1 area 18 opening

2-2 Area 19 Circular area

3 deflection device 20 circular ring

3a deflection 21 circular ring

3b deflection 22 segment

4 optical sensor 23 tilting mirror array

4a optical sensor 24a micromirror

4-1 Position of the optical 24b micro mirror

Sensor 25 light source

4-2 Position of the optical 26 arrow

Sensors 27 light trap

5 Object 28 Contour

6 controllable element 29 area

6 'Straight 30 line

7 arrow 31 line

7a arrow 32 turned on

8 optical axis lighting element

8a optical axis 33 off

9 lens lighting element

10 detector

Claims

Claims Method and device for illuminating and measuring an object

1. Device for incident light illumination and/or transmitted light illumination of an object (5) by means of an illumination source (2), the radiation emanating from the illumination source being able to be coupled into the beam path of an optical sensor (4), preferably an image processing sensor, and imaged onto the object or the Illumination source is arranged on the side of the object facing away from the optical sensor,

characterized,

that the lighting source (2) is a flat lighting source and that the lighting source comprises at least a plurality of lighting elements (6) which can be switched independently of one another.

2. Device according to claim 1,

characterized,

in that the lighting source (2) comprises a plurality of independently switchable lighting elements (6), which can be switched depending on the position of the optical sensor (4) and/or that individual or several groups of the lighting elements can be switched independently of one another, a group consisting of one lighting element or several lighting elements.

3. Device according to claim 1 or 2,

characterized,

that only the lighting elements (6) can be switched, which are arranged within a fixed angular range to the optical axis (8) of the optical sensor (4) in a plane that is perpendicular or almost perpendicular to the optical axis (8), preferably the angular range around a definable one Angle of, for example, 1° or 3° or 5° is greater than the acceptance angle resulting from the numerical aperture of the lens assigned to the optical sensor.

4. Device according to at least one of the preceding claims,

characterized,

that the optical sensor (4) can be moved at least at right angles or almost at right angles to its imaging direction and the illumination source (2) has a larger extent than the area that can be detected by the fixed optical sensor, preferably covering the entire area that can be detected by the moving optical sensor.

5. Device according to at least one of the preceding claims,

characterized,

that the illumination source (2) is fixedly arranged and the optical sensor (4) can be moved relative to the illumination source in at least one direction perpendicular or almost perpendicular to its imaging direction, or that the illumination source runs in a first perpendicular or almost perpendicular to the imaging direction of the optical sensor Direction is movable and the optical sensor is movable in a second direction, perpendicular or almost perpendicular to the imaging direction of the optical sensor and perpendicular or almost perpendicular to the direction of movement of the lighting device.

6. Device according to at least one of claims 1 to 3,

characterized,

in that the object (5) and optical sensor (4) can be moved relative to one another in the direction of the imaging direction of the optical sensor and preferably at right angles or almost at right angles to the imaging direction of the optical sensor and the illumination source (2) has an extent which is at least that of the respective relative to the Object fixed optical sensor detectable surface illuminated, and the illumination source is fixed relative to the optical sensor.

7. Device according to at least one of the preceding claims,

characterized,

that the lighting elements (6) forming a surface are at least lighting elements from the group of LCD matrix, LED matrix, OLED matrix, LCoS matrix, fiber bundles, at least one micromirror array.

8. Device according to at least one of the preceding claims,

characterized,

that the radiation from the illumination source (2) hits the object plane in an unfocused manner.

9. Device according to at least one of the preceding claims,

characterized,

that the radiation from the illumination source (2) can be focused into the focal plane of the optical sensor by means of optics (9) connected to the optical sensor (4) or already contained in the optical sensor.

10. Device according to at least one of the preceding claims,

characterized,

that several selected lighting elements (6) of the lighting source can be controlled together, which form a pattern, preferably several different patterns can be generated one after the other.

11. Device according to at least one of the preceding claims,

characterized,

that the coupling takes place with means for deflecting the radiation from the illumination source (2), such as deflection mirrors (3), splitter cubes, splitter plates or pellicles, preferably using partially transparent optical layers or wavelength-selective layers or vibration direction-selective layers.

12. Device according to at least one of the preceding claims,

characterized,

that the coupling between the object (5) and the side facing the object takes place by optical elements of the optical sensor (4).

13. Device according to at least one of the preceding claims,

characterized,

that the coupling takes place between the optical elements of the optical sensor (4) or between the optical elements and image sensor (10) of the optical sensor.

14. Device according to at least one of the preceding claims,

characterized,

that the transmitted light illumination is arranged on the side of the object (5) opposite the optical sensor (4) and can preferably be coupled in without deflection.

15. Device according to at least one of the preceding claims,

characterized,

that between the illumination source (2) and the coupling an optical element, such as a lens (12) and/or a diaphragm (14, 15) and/or filter, which transmits rays smaller than a defined critical angle to the central direction of the rays of the illumination source, is preferably formed is arranged by an arrangement of several elements (17) which are tubular or honeycomb-shaped and arranged next to one another in the radiation direction.

16. Device according to at least one of the preceding claims,

characterized,

that the illumination source or an illumination device comprising the illumination source is integrated into a coordinate measuring machine and the control of the illumination source or illumination device and the optical sensor (4) is connected to the control of the coordinate measuring machine is, and preferably two lighting sources or lighting devices can be used, which are arranged on opposite sides of the object (5) and preferably two optical sensors (4, 4a) can be used, which are arranged on opposite sides of the object.

17. Device according to at least one of the preceding claims,

characterized,

that the multitude of lighting elements (6) such as fibers or micromirrors (24) of the lighting source emit light of different wavelengths, preferably by using an RGB matrix lighting source.

18. Device according to at least one of the preceding claims,

characterized,

that the lighting elements (6) are arranged in a plane which preferably runs parallel or perpendicular to the support surface of the object (5) to be measured.

19. Device according to at least one of the preceding claims,

characterized,

that only the lighting elements (6) can be switched on, at which the angle Phi between the optical axis (8) of the sensor (4) and the direction of the direct connecting line (6 ') between the lighting element and the optical sensor is <10°, preferably <3° , particularly preferably <1°.

20. Device according to at least one of the preceding claims,

characterized,

that in an illumination beam path, preferably a bright field illumination beam path, before being reflected into the beam path of an optical sensor (4), preferably an image processing sensor with a focus sensor function, a mark, such as a chrome mask, with translucent and opaque areas is arranged, which are in the focal plane of the optical Sensor assigned optics with adjustable working distance can be focused in a first setting for the working distance and in at least one further focal plane changed working distance can be imaged out of focus, preferably in that the optics contain at least one lens that can be adjusted to adjust the working distance of the optics, through which the illumination beam path can only pass after reflection on the object, i.e. is arranged between the reflection and the receiver of the optical sensor, the mark can preferably be formed by the plurality of lighting elements of the lighting source, with only selected lighting elements being switched on.

21. Method for incident light illumination and/or transmitted light illumination of an object (5) by means of an illumination source (2), the radiation emanating from the illumination source being coupled into the beam path (8) of an optical sensor (4), preferably an image processing sensor, and imaged onto the object or the illumination source is arranged on the side of the object facing away from the optical sensor,

characterized ,

that a flat illumination source is used as the illumination source (2) and that the illumination source is formed at least from a plurality of lighting elements (6), that the individual lighting elements are switched on and/or adjusted independently of one another, preferably the individual lighting elements are divided into groups and the individual or multiple groups are switched on and/or adjusted independently of one another, such that bright field incident light illumination or dark field incident light illumination or transmitted light illumination or a mixture of the types of illumination is achieved.

22. Method according to claim 21,

characterized ,

in that the lighting source (2) comprises a plurality of lighting elements (6) which are to be switched on and/or adjusted independently of one another and which are switched on and/or adjusted depending on the position of the optical sensor.

23. Method for determining measuring points on the surface of an object (5) with an optical sensor (4) according to the focus principle, preferably confocal focus principle, consisting of at least one flat receiver or image sensor such as a CCD or CMOS sensor with a plurality photosensitive elements for recording two-dimensional images, using incident light illumination according to at least claim 21, wherein the radiation emanating from the illumination source is coupled into the beam path of the optical sensor and imaged onto the object, and wherein a parameter characteristic of the surface of the object, such as contrast value and/or intensity value is determined in several relative positions varying in the direction of the optical axis (8) of the optical sensor between the object surface and the focal plane of the sensor by recording two-dimensional images, and from the relative position and the characteristic parameter the coordinate of at least one measuring point present along the optical axis is determined, whereby the measuring area determined by the images perpendicular to the optical axis is divided into partial areas,

characterized ,

in that a flat illumination source (2) is used, which is formed from a plurality of lighting elements (6) which are controlled independently of one another, i.e. switched on and/or adjusted, the respective controlled lighting elements forming patterns which respectively represent selected sub-areas of the measuring range illuminate.

24. Method according to at least one of the preceding claims 21 to 23,

characterized ,

in that the radiation emanating from the illumination source (2) is focused into the focal plane of the optical sensor (4), preferably by optics (9) connected to the optical sensor or already contained in the optical sensor, and preferably the illumination source is fixed relative to the optical sensor .

25. Method according to at least one of the preceding claims 21 to 24, characterized in

that the partial areas are assigned to individual pixels or groups of neighboring pixels of the receiver (10) of the optical sensor (4).

26. Method according to at least one of the preceding claims 21 to 25,

characterized,

in that the object (5) is illuminated in such a way that the respective plurality of partial areas illuminated by the respective pattern in the focused state are spaced apart from one another, preferably arranged at a distance from one another that is at least twice, preferably at least 5 times, particularly preferably corresponds to at least 10 times the side length of the partial area.

27. Method according to at least one of the preceding claims 21 to 26,

characterized,

in that the object (5) is illuminated in such a way that the multiple partial areas illuminated by the respective pattern are spaced apart from one another in such a way that during the relative movement there is no superimposition of the multiple illuminated partial areas due to the defocusing of the pattern that occurs.

28. Method according to at least one of the preceding claims 21 to 27,

characterized,

that for the partial areas illuminated by the respective pattern, the characteristic parameter and the resulting coordinate are determined simultaneously or essentially simultaneously during the variation of the relative position between the object surface and the focal plane of the sensor (4), the coordinate present perpendicular to the optical axis (8). is determined from the position of the partial area in the image and of the optical sensor relative to the object perpendicular to the optical axis.

29. Method according to at least one of the preceding claims 21 to 28, characterized in

that for each distance or distance range, an overall image is put together from the partial images assigned to the partial areas, and the distance between the optical sensor (4) and the measurement object surface is determined for each partial area by at least taking into account the position of the respective partial image, for which the respective partial area is like pixels has the highest contrast or the highest intensity or brightness.

30. Method according to at least one of the preceding claims 21 to 29,

characterized,

that relative movements are carried out several times in succession using different patterns or different patterns are set repeatedly in several cycles during a single relative movement, with several measuring points being determined for each pattern, the respective selected sub-areas being determined in accordance with the respective pattern.

31. Method according to at least one of the preceding claims 21 to 30,

characterized,

that the different patterns are shifted relative to one another or varied until all partial areas have been illuminated at least once.

32. Method according to at least one of the preceding claims 21 to 31,

characterized,

that only the lighting elements (6) are switched on or adjusted that are arranged within a defined angular range to the optical axis (8) of the optical sensor (4), preferably the angular range is larger by a definable angle of, for example, 1° or 3° or 5° is the acceptance angle resulting from the numerical aperture of the lens assigned to the optical sensor.

33. Method according to at least one of claims 21 to 32,

characterized,

that only the lighting elements (6) are switched on at which the angle Phi between the optical axis of the sensor and the direction of the direct connecting line (6 ') between the lighting element and the optical sensor is <10°, preferably <3°, particularly preferably <1° amounts.

34. Method according to at least one of the preceding claims 21 to 33,

characterized,

that in order to measure one or more features of the object (5), the optical sensor (4) is moved at right angles or at least almost at right angles to its imaging direction and the illumination source (2) has a larger extent than the surface that can be detected by the fixed optical sensor, preferably the entire area Covers the area that can be detected by the moving optical sensor.

Method according to at least one of the preceding claims 21 to 34, characterized in

that the illumination source (2) is fixedly arranged and to measure one or more features of the object (5), the optical sensor (4) is moved with respect to the illumination source in at least one direction at right angles or almost at right angles to its imaging direction, or that to measure one or several features of the object, the illumination source is moved in a first direction which is perpendicular or almost perpendicular to the imaging direction of the optical sensor and the optical sensor is moved in a second direction which is perpendicular or almost perpendicular to the imaging direction of the optical sensor and at right angles or almost perpendicular to the direction of movement of the lighting device is moved.

36. Method according to at least one of claims 21 to 35,

characterized,

37. Method according to at least one of claims 21 to 36,

characterized,

that in order to generate the bright field incident light illumination, lighting elements (6) are grouped in the middle of the illumination source (2), preferably neighboring lighting elements in a circle.

38. Method according to at least one of claims 21 to 37,

characterized,

that outside the center of the illumination source (2) lighting elements (6) are controlled to generate the dark field incident light illumination, preferably in the form of circular rings (29, 21), preferably several radially offset circular rings being switchable in order to achieve different illumination angles of the dark field illumination, and preferably the circular rings are divided into segments (22) along the circumference in order to achieve different directions of dark field illumination.

39. Method according to at least one of claims 21 to 38,

characterized,

in that to generate the transmitted light illumination, all the lighting elements (6) of the illumination source (2) are grouped, with micromirrors (24) preferably being used, the directions of which are adjusted to generate parallel light, or the micromirrors are grouped to generate diffuse light and adjusted in different directions .

40. Method according to at least one of claims 21 to 39,

characterized,

that the directions of the micro mirrors (24) of at least one group are changed to switch between the switched-on state and the switched-off state of the respective type of lighting or to switch between bright field and dark field lighting.

41. Method according to at least one of claims 21 to 40,

characterized,

that transmitted light illumination and bright field illumination and/or dark field illumination are achieved by a single illumination source, and two optical sensors (4, 4a), which are arranged on opposite sides of the object, are used to measure the object (5) from two sides.

42. Method according to at least one of claims 21 to 41,

characterized,

that the color of the transmitted light illumination and/or incident light illumination is set by controlling the corresponding lighting elements (6), preferably different colors being set for the types of illumination or the different dark field circular rings or segments.

43. Method according to at least one of claims 21 to 42,

characterized,

that the method is used in a coordinate measuring machine.

44. Method according to at least one of claims 21 to 43,

characterized,

that those from the group of two-dimensional LCD matrix, LED matrix, OLED matrix, LCoS matrix, fiber bundles, and at least one micro mirror array are used as lighting elements.

45. Method according to at least one of claims 21 to 44,

characterized ,

that the lighting elements (6) to be switched on are fixed in accordance with a preliminary measurement of the object contours (28) or the object boundary with the optical sensor (4), preferably in different relative positions between the sensor and the object (5), with all lighting elements of each being in the preliminary measurement The selected type of illumination, transmitted light or reflected light, or at least the part of the lighting element that is necessary for complete illumination of the object, is switched on and the contours or the edge of the object are roughly determined in their position, and then only depending on the relative position between the sensor and the object the lighting elements are switched on, which contribute to the illumination of the roughly determined contour detected by the sensor at the predeterminable maximum angle Phi.

46. Method according to at least one of the preceding claims 21 to 45,

characterized ,

that in order to increase the contrast of the surface of an object (5) detected by an optical sensor (4) in an illumination beam path, preferably a bright field illumination beam path, before reflection into the beam path of an optical sensor, preferably an image processing sensor with a focus sensor function, a mark, such as a chrome mask, with translucent and opaque areas and is focused into the focal plane of the optics by setting a first working distance of the optics assigned to the optical sensor with an adjustable working distance, the mark being imaged out of focus in at least one further focal plane of a changed working distance, preferably by the optics being at least one contains an adjustable lens for adjusting the working distance of the optics, which is passed through by the illumination beam path only after reflection on the object, i.e. is arranged between the reflection and the receiver of the optical sensor, the mark preferably being formed by only selected ones from the large number of lighting elements of the illumination source Lighting elements are switched on.

47. Method according to at least one of the preceding claims, characterized in

that the plane spanned by the lighting elements (6) to form the illumination source (2) is aligned with the optical axis (8) of the optical sensor in such a way that the normal of the plane corresponds to the optical axis (8) of the optical sensor (4) at an angle α 70° < α < 110°, in particular α = 90°.

48. Method according to at least one of the preceding claims,

characterized,

that the coherent closed surface formed by the lighting elements as the illumination source (2) is penetrated by the optical axis (8) of the optical sensor (4), in particular in the middle, after the radiation has been aligned with the object to be measured (5).

49. Method according to at least one of the preceding claims,

characterized,

that the lighting elements are arranged in relation to the flat lighting source (2) in such a way that 100 to 10,000 lighting elements per cm are present.