Chromatic confocal measurement device

Abstract

To provide a cost-effective light source suitable for high frequency driving of a chromatic confocal linear detector.SOLUTION: A chromatic confocal measuring device for measuring intervals and / or thickness of a plurality of locations has a light source (1) that emits polychromatic measuring light (2), at least one first confocal aperture (3 and 10) through which the measuring light (2) passes, and number of punctiform orifices or at least one slit-shaped orifice. An imaging optical system (4 and 5) is configured to cause a chromatic focus shift of the measuring light and various wavelengths are focused at various heights. A first receiving and evaluating unit (8) is formed to measure intensity of the measuring light reflected by a measurement object according to the wavelengths and a transversal position of a reflection location on the measurement object and determine the intervals and / or the thicknesses of the plurality of locations of the measurement object (6). The light source (1) is a laser pumped luminophore-based light source and has a vertically long exit surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The invention relates to a chromatic confocal measuring device for simultaneously measuring the distance and / or thickness of a plurality of locations or areas extending in at least one spatial direction of a measuring object. The measuring device has a light source emitting polychromatic measuring light through a light emission surface and at least one first confocal aperture through which the measuring light emerges. The first confocal aperture has a number of point-like openings or at least one slit-shaped opening. The measuring device also has imaging optics, which are arranged to bring about a chromatic focus shift and to image the first confocal aperture into a measuring volume, whereby different wavelengths are focused at different heights, and the measuring device has a first receiving and evaluating unit, which is formed to measure the intensity of the measuring light reflected from the measuring object according to the wavelength and the transversal position of the reflection locations on the measuring object and to determine the distance and / or thickness of a plurality of locations or areas extending in at least one spatial direction of the measuring object on the basis of this. [Background technology]

[0002] From WO 2016 / 092348 A1 a chromatic confocal height measuring device is known which has a number of measuring points arranged in a line in order to expand the measuring volume transversely to the optical axis.

[0003] DE 10 2018 114 860 A1 further describes a chromatic confocal measuring device which has a slit diaphragm as a confocal diaphragm, so that extended, continuous areas of the measuring object can be measured along the projection of the diaphragm.

[0004] These known measuring devices have the disadvantage that either the light of a point-like light source must be distributed over the entire measuring volume (which leads to a reduction in intensity and therefore a limitation of the possible measuring rate) or a large number of point-like light sources must be used, which leads to high costs. The known light sources have too small an initial power to drive a chromatic confocal linear detector at high frequencies. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2016 / 092348(A1) [Patent Document 2] German Patent Application Publication No. 102018114860(A1) Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE DISCLOSURE It is therefore an object of the present invention to provide a cost-effective light source suitable for driving a chromatic confocal linear detector at high frequencies. [Means for solving the problem]

[0007] This problem is solved by providing a luminescent material-based light source having an elongated light output surface.

[0008] Phosphor-based light sources are light sources in which a luminescent substance (phosphor) is excited by a pump source (e.g. laser or LED), which emits light by a physical process, in particular phosphorescence, fluorescence or scintillation. Phosphors here are generally substances that convert radiation.

[0009] An elongated exit surface means that its area in one spatial direction is in particular at least an order of magnitude larger than in the other spatial direction.

[0010] Luminescent-based light sources are known per se, but none have been suitable for this application.

[0011] The present invention therefore provides a measuring device of the above-mentioned type, whose light source is a laser-pumped phosphor-based light source with an elongated exit surface, which has the advantage that the light source can sufficiently illuminate the entire confocal aperture and thus has high efficiency and high light yield.

[0012] The first confocal aperture has a number of dot-shaped openings or at least one slit-shaped opening. In particular, the dot-shaped openings are preferably arranged in a row with regular intervals. The dot-shaped openings are so-called multipoint sensors arranged to measure a row of points on the measurement object. In this case, the first confocal aperture can also be formed as the end of a row of fibers, each fiber end then corresponding to a dot-shaped opening. If the first confocal aperture has slit-shaped openings, it is a so-called chromatic line sensor, which is arranged to illuminate and measure a line-shaped area on the measurement object. The density of the measurement points in the line-shaped area is then related to the receiving and evaluation unit and its transversal resolution.

[0013] The first receiving and evaluating unit preferably comprises a spectrometer, which detects the intensity of the received light according to wavelength.

[0014] According to a preferred embodiment of the invention, the light source has at least one pump source, which emits and directs pump light onto the light emitter, which converts the pump light into polychromatic light. The pump light is usually nearly monochromatic. As pump source, preferably, a laser diode is used, since it can achieve high intensities.

[0015] The pump light can also be converted into polychromatic light by multiple emitters arranged separately from each other.

[0016] In some embodiments, the polychromatic light then passes through a homogenizer in such a way that the intensity of the light emerging from the exit surface is approximately uniformly distributed. The homogenizer is preferably formed as a thin plate, preferably made of glass, through which the light propagates substantially in a first spatial direction, while the plate acts as a waveguide in a second spatial direction, such that the light spreads in a third spatial direction and can thus be uniformly distributed. This has the purpose of illuminating uniformly over the measurement volume. The light emitters here can be approximately point-shaped or have a small volume.

[0017] The homogenizer can have a section, for example with the shape of a pyramidal base, preferably square, which is arranged such that the polychromatic light enters the section through the top surface of the pyramidal base. Surprisingly, it has been found that a pyramidal shape leads to a particularly homogeneous intensity distribution at the base of the pyramidal base. If the homogenizer is rotationally symmetric, then there is usually an undesirable concentration of the polychromatic light on the axis of symmetry.

[0018] A pyramidal homogenizer is even more effective if a modifier, as described below, is used, which makes the cross section of the light distribution more elongated and into which the polychromatic light must be coupled. If the modifier comprises, for example, an optical fiber, the polychromatic light can only enter the fiber at a small angle. The shape of the pyramidal base minimizes the proportion of light that strikes the fiber at too steep an angle.

[0019] The sides of the pyramid base can then be inclined in such a way that the polychromatic light guided in the sections is guided in the homogenizer by total reflection, thereby eliminating the need for mirror-finishing the sides.

[0020] A homogenizer of the described kind can also be combined with all the following embodiments.

[0021] According to a preferred embodiment of the invention, the light emitter is rod-shaped. The light exiting through the side of the rod-shaped light emitter is preferably used as the measuring light. The side is then a surface extending over the length of the rod. This has the advantage that only one pump source and one light emitter are needed to emit light through an elongated area, where the light is emitted from one continuous area instead of from multiple point sources.

[0022] The rod-shaped illuminator can then have a base (and cross-section) of any shape, for example circular or polygonal. The base is the face at the end of the rod. The geometric shape is therefore a cylinder or prism, whose height is much larger than the diameter of the base.

[0023] In that case, the light preferably enters through one of the bottom faces of the rod-shaped light emitter. Another preferred possibility is to pump from both bottom faces of the rod-shaped light emitter, which improves the light yield and at least partially homogenizes the emission over the rod length.

[0024] Alternatively, the pump light enters through the side of the light emitter, in which case multiple pump sources are used over the length of the rod-shaped light emitter, or the pump light of a single pump source is focused onto the linear section at the location of the light emitter by focusing optics, e.g. with a cylindrical lens.

[0025] The preferably rod-shaped illuminators are shaped to act as waveguides for the pump light and / or the measurement light, which is obtained in particular by the selection of surface properties (smooth surfaces) and by a small diameter (typically around 5 μm or around 50 μm, depending on the respective desired waveguide type).

[0026] LED emitters usually have a medium wavelength in the region of 0.2 mm to 0.5 mm for absorption and frequency-shifted light emission. In the case of approximately point-shaped light sources, in order to obtain a small enough emission spot for point-like interval measurements, the pump light must be defined within a small emission area of ​​less than 100 μm due to multiple scattering of the light at the grain boundaries. With rod-shaped emitters, the pump light can be guided linearly and without scattering, as in a single or multimode fiber (waveguide).

[0027] According to a particularly preferred embodiment of the invention, the light source has a slit diaphragm, in which case the slit of the slit diaphragm is the light exit surface of the light source. The slit can be used at the same time as the first confocal aperture of the measuring device. By means of the diaphragm, light that is not directed through the exit surface is effectively blocked so as not to affect the measurement.

[0028] According to a particularly preferred embodiment of the invention, the slit diaphragm is tilted with respect to the longitudinal axis of the rod-shaped light emitter. This has the advantage that the non-uniform emission of light can be at least partially compensated over the length of the light emitter, since a percentage more light passes through the part of the slit diaphragm closer to the light emitter than through the part further away. Therefore, in a preferred manner, the slit diaphragm is tilted closer to the less light-emitting areas of the light emitter and further away from the more light-emitting areas of the light emitter.

[0029] According to a particularly preferred embodiment of the invention, the front surface of the rod-shaped light emitter, opposite to the entrance surface through which the pump light enters the light emitter, is made mirror-finished, which has the effect that the pump light, which passes completely through the light emitter, is reflected at the end and passes through the light emitter again, which leads to a higher yield and a more uniform emission.

[0030] According to a particularly preferred embodiment of the invention, the light emitter is formed in a cone-like shape, in particular as a truncated cone or a cone. This results in a more uniform light yield. Preferably, the entrance surface here is the larger base of a truncated cone or the base of a cone. In this case, the preferably cone-like light emitter is formed to act as a waveguide for the pump light. This causes the pump light to be concentrated in a narrower part of the cone / frustum, which results in a higher yield per unit volume.

[0031] According to a particularly preferred embodiment of the invention, the light source comprises a parabolic mirror, which focuses the light so that it does not exit the light emitter in the direction of the exit surface of the light source, at least partially in the direction of the exit surface, thus allowing a higher yield.

[0032] According to a particularly preferred embodiment of the invention, a part of the jacket surface of the rod-shaped light emitter (part of one / several side surfaces and / or at least one bottom surface) is mirrored, while the desired exit surface is not mirrored, which results in a higher light yield, since the radiation that is not emitted in the direction of the light exit surface is at least partially reflected in the direction of the light exit surface.

[0033] Preferably, the luminescent body consists of a mixture of different luminescent materials that emit light of different wavelengths. This results in a broader polychromatic spectrum. Sometimes the effect of secondary emission occurs when light of a first emission wavelength excites other luminescent materials that emit light of a larger emission wavelength.

[0034] Preferably, a homogeneous mixture of the various luminescent materials is used.

[0035] Preferably, the mixture ratio of the various luminescent materials is varied over the length and / or over the radius of the rod-shaped luminescent body, whereby the effects of secondary emission can be utilized or compensated for. Layer structures with pure layers of various substances are also possible.

[0036] Preferably the phosphor consists of a single crystal or consists of a pressed powder.

[0037] According to a preferred embodiment of the invention, the measuring device has a second receiving and evaluating unit, which is designed to detect an image of the measuring object, in particular as a so-called chromatic camera, which utilizes different focal positions of different wavelengths on the object in order to generate an image with an improved depth of focus.

[0038] According to a preferred embodiment of the invention, the measuring device has a second imaging optics, which is formed spatially separated from the first imaging optics, in which case the first imaging optics and the second imaging optics each have additional optical elements, which bring about a chromatic focus shift transversely to the optical axis of the respective imaging optics (or more precisely, the lenses of the respective imaging optics).

[0039] The first imaging optics can be arranged to form focal points of different wavelengths at different locations, where those locations lie along a line segment that forms an acute angle with respect to the optical axis of the lens of the first imaging optics.

[0040] According to a preferred embodiment of the invention, the light source comprises at least one pump source, which emits pump light, whereby the pump light is converted into polychromatic light by a plate-shaped light emitter.

[0041] A plate-shaped light emitter is then a light emitter which extends in two spatial directions but has only a small extent in the third direction. The light emerging through the side of the plate-shaped light emitter is then used in an efficient manner as measuring light, this side being then a surface perpendicular to the base (which then extends in two dimensions).

[0042] The emitter is made of a transparent material with a homogeneous refractive index, so that the pump light and the emitted light are transmitted linearly and without scattering over several millimeters. Single crystals doped with ions from the rare earth group, for example Ce; YAG, are suitable. Transparent ceramics or glasses doped with photoluminescent centers can also be used.

[0043] Single crystals from Crytur are also suitable. They have a high refractive index (1.82 at 532 nm) but are hard and difficult to process. Typical plate thicknesses are 200 μm. For reasons of ease of construction, it can be advantageous to use a cover plate made of a single crystal of this type, which is glued onto a carrier plate and ground thin.

[0044] The use of plate-shaped light emitters in this case has the advantage that a very homogeneous light distribution can be achieved in a simple manner for the light emerging from the sides.

[0045] Preferably, the light of the pump source is incident through a side of the plate-shaped light emitter, particularly preferably through the side opposite to the side from which the measurement light emerges.

[0046] Typically blue (e.g. 450 nm) or violet (e.g. 405 nm) light is absorbed by the photoluminescence centers and re-emitted isotropically (i.e. equally in all directions) at a shifted wavelength. Since the generated polychromatic light is not scattered or absorbed (apart from being suitable as such for exciting fluorescence), its intensity is accumulated.

[0047] For each point on the side of the illuminant from which the fluorescent light leaves the illuminant, a capture region is defined within the plate-shaped illuminant, i.e. a cone-shaped volume with a given opening angle, having its apex within the point-like opening.

[0048] All light that occurs within the capture area of ​​the point-like opening and travels to the lateral point can be used as measurement light. On the way there, the intensity fraction of the light that can be coupled in increases continuously (accumulation).

[0049] If the measurement light is coupled into an optical fiber located behind the side, the opening angle of the cone is given by the maximum aperture angle of the fiber. If the measurement light is not transported through an optical fiber after leaving the light emitter but through free beam optics, the opening angle is given by the aperture of the optics.

[0050] The polychromatic light passing through the bottom surface and the side surfaces not used as the light exit surface of the light emitter cannot be used as the measurement light. Therefore, in a preferred embodiment, the bottom surface and the side surfaces not used as the light exit surface are formed as mirror surfaces.

[0051] Furthermore, polychromatic light that impinges at too large an angle onto the side through which the measuring light passes cannot be used as measuring light, since its origin lies outside the capture area of ​​the point-like aperture.

[0052] Thus, in a preferred embodiment, the plate-shaped light emitter has a wedge angle between the two bases, where the wedge between the two bases is formed such that the distance between the bases at the location of the side where the measurement light passes is greater than the distance at the location of the side where the pump light enters. The wedge angle along the side where the pump light enters is preferably between 1° and 10°.

[0053] The wedge shape of the plate-shaped illuminator, possibly also with a mirrored bottom surface, guides the fluorescent light towards the light exit surface at an increasingly flatter angle after multiple reflections, thus making a larger proportion of the fluorescent light available.

[0054] According to another preferred embodiment, a light consisting of measuring light exiting from several sides is used. For example, two fiber arrays are attached to two sides of a plate-shaped light emitter. The fiber ends of the respective ends of the two fiber arrays facing away from the light emitter can be arranged in such a way that they form a line of point-like openings and thus an elongated light exit surface. The optical fibers thus form a deformation device, which is arranged in such a way that it deforms the light distribution generated by the light emitter in such a way that the cross section of the light distribution becomes more elongated.

[0055] When using a plate-shaped light emitter, the transformation device can have a number of fibers, each having a first fiber end and a second fiber end, where the first fiber end receives the polychromatic light exiting from one or more sides of the plate-shaped light emitter, where the second fiber end is arranged in a line and forms the light exit surface, where the second fiber end can be used simultaneously as a confocal aperture.

[0056] In an alternative embodiment, the pump source light is incident through the bottom surface of the plate-shaped emitter, which has the advantage that more area is provided for coupling the pump light into the emitter than if it were coupled through the side.

[0057] Thereby, even with pump light sources having a relatively low luminous density, a sufficiently large accumulated pump light output can be obtained when a large part of the bottom surface is illuminated. In particular, LED arrays are used as pump light sources, which represent a cost-effective alternative to, for example, laser diodes.

[0058] LEDs emit light over a surface. They can be manufactured more easily than laser diodes and have a higher electro-optical efficiency. Due to the surface emission, they are cooled more easily than laser diodes. On the other hand, their luminous density is much smaller than that of laser diodes. The transparency of the illuminant and the accumulation effect make it possible for the first time to accumulate the luminous density of all volume sections and make it sufficient for measurement techniques.

[0059] In this case, in a preferred embodiment, the bottom surface facing the light entrance surface of the pump light is formed as a mirror, which has the advantage that the pump light which strikes this bottom surface does not leave the light emitter but can contribute to the generation of the measuring light on its return path after reflection.

[0060] The plate-shaped light emitter is preferably made thin, for example with a thickness of 50-200 μm, which is comparable to the typical diameter of a multimode fiber, so that a large part of the light impinging on the side that is used as the light exit surface can be used as measuring light.

[0061] Of course, in that case, the typical wavelength of the pump light in the illuminant is a few hundreds of microns, so that most of the pump light cannot contribute to the generation of fluorescent light, regardless of the mirroring.

[0062] Therefore, in a preferred embodiment, the bottom surface opposite the light incidence surface of the pump light is provided with a texture covering the pyramid surface. This texture prevents the pump light from traversing the plate vertically and in the shortest possible route. The pyramid texture does not need to be inserted into the phosphorus material. A textured ceiling surface is sufficient.

[0063] According to a preferred embodiment, the light source has a slit diaphragm, in which case the slit of the slit diaphragm is the light exit surface of the light source, which can simultaneously be used as a first confocal aperture of the measuring device.

[0064] The use of a deformation device arranged to deform the light distribution generated by the illuminant so that it becomes more elongated generally has the advantage that the light yield is optimized. In rod- and plate-shaped illuminants, for example, only that part of the fluorescent light which impinges on the light exit surface below a certain limit angle (when a fiber array is used, the limit angle is given for example by the maximum acceptance angle of the fibers) is used as measurement light.

[0065] Furthermore, the geometry of the rod- or plate-shaped illuminators must be adapted to the geometry of the confocal aperture of the measuring device in order to allow as homogeneous an illumination of the confocal aperture as possible.

[0066] These two limitations are addressed by using a transformation device that takes the planar light distribution of the fluorescent light generated by the light emitter and transfers it to an elongated light exit surface.

[0067] In a preferred embodiment, a planar arrangement of optical subelements is used as the modification device, whereby the subelements can in particular be optical fibers or microlenses.

[0068] The optical fibers can be arranged such that a first fiber end of each optical fiber is arranged in a plane to receive the polychromatic light emitted by the light emitter, and a second fiber end of each optical fiber is arranged in a line to emit the polychromatic light, where the arrangement of the second fiber ends forms an elongated light emission surface of the light source.

[0069] The arrangement of the microlenses can be formed such that the microlenses are on one surface and divide the polychromatic light into partial bundles, each of which is guided further via other optical elements, for example deflection mirrors, and the individual light bundles are guided together in such a way that they form an elongated light surface.

[0070] The surface arrangement of the optical subelements is optimized in particular in order to accommodate as large a proportion as possible of the polychromatic light emitted by the light emitters and to be available as measuring light.

[0071] In a preferred embodiment, the light generated by the light emitter is collimated and the surface arrangement of subelements is mounted on a circular surface inside the collimated beam. In an alternative embodiment, the light emitter emits light in all spatial directions and the surface arrangement of subelements is arranged on a spherical surface or a portion of a spherical surface centered on the light emitter.

[0072] The advantage of a light source using a transformation device that receives a planar distribution of polychromatic light and transforms it into a vertical light distribution is that the geometry of the light emitter does not have to be adapted to the geometry of the (vertical) confocal aperture and can be made to produce the highest possible light yield.

[0073] In a preferred embodiment, the illuminant has a section in the shape of a truncated cone, into whose top surface pump light is coupled so that the pump light generates polychromatic light within the illuminant, the jacket surface of the illuminant being mirror-finished so that the polychromatic light cannot leave the illuminant through the jacket surface, but is reflected at the jacket surface.

[0074] A part of the polychromatic light generated in the light emitter impinges on the jacket surface of the truncated cone, in which case, if the projection of the light beam on the axis of symmetry of the truncated cone points in the direction of the base, the angle between the light beam and the axis of symmetry decreases after reflection.

[0075] The polychromatic light finally passes through the base of the truncated cone at a small angle to the axis of symmetry of the truncated cone and forms a circular planar light distribution.

[0076] This light is contained by a transformation device, such as a planar arrangement of fiber ends, and transferred to a longitudinal light distribution.

[0077] In another preferred embodiment, the light emitter has a cylindrical section, in whose jacket surface an entrance window for pump light is arranged, through which the pump light enters the cylindrical light emitter in such a way that the pump light strikes the inside of the cylindrical jacket at a flat angle and is totally reflected.

[0078] The cylindrical illuminator is shaped such that the pump light traces a spiral track inside the illuminator, so that the illuminator acts as a "trap" for the pump light, which then contributes fully to the generation of polychromatic light.

[0079] Polychromatic light leaves the illuminant through the jacket surface and the bottom surface and is therefore emitted in all directions.

[0080] To capture and further guide the polychromatic light, a planar arrangement of fibers can be used, the fibers being arranged on a plane centered on the illuminant, and in particular an arrangement of fibers arranged on a spherical surface or a part of a spherical surface surrounding the illuminant.

[0081] In an alternative embodiment, the light emitter has a frusto-conical section, where the entrance window is located near the bottom surface and the pump light travels in the light emitter on a spiral track towards the top surface, whereby due to the inclination of the jacket surface the pitch height of the spiral track continuously decreases until the pump light finally extends on the spiral track towards the bottom surface.

[0082] This configuration has the advantage that due to the larger travel distance of the pump light, the emitter can be made more compact for the same yield.

[0083] This compactness is further increased if the light emitter is formed as two truncated cones joined at their bases, in which case the entrance window is located near one of the bases: the light which runs on a spiral track towards the ceiling of one of the truncated cones and then back to the base, after passing through the base in the second truncated cone, is guided on a spiral track to the second ceiling and back to the base.

[0084] In another embodiment, the illuminator has a section with the shape of a pyramid truncated, preferably square. This section is arranged relative to the pump source in such a way that the pump light enters the illuminator through the top surface of the pyramid truncated. A part of the polychromatic light generated in the illuminator impinges on the jacket surface of the pyramid truncated. If the projection of the light beam on the axis of symmetry of the truncated cone then points towards the base, then after reflection the angle between the light beam and the axis of symmetry is reduced. The polychromatic light finally passes through the base of the pyramid truncated at a small angle to its axis of symmetry and is therefore more easily accommodated by the downstream transformation device, which transforms the polygonal light distribution generated by the pyramid truncated into a linear light distribution.

[0085] Such shaped emitters are easier and more cost-effective to produce than frusto-conical emitters, and produce a more homogeneous intensity distribution.

[0086] These sides should be mirrored to ensure that neither the pump light nor the polychromatic light generated within the illuminator leaves the pyramid base through these sides.

[0087] Adjacent to the base of the pyramid base, a homogenizer can be placed, which further homogenizes the polychromatic light but does not necessarily change the angular distribution any further. The homogenizer can be, for example, square-shaped and adapted to the cross-section of the light emitter.

[0088] The modification device can have, for example, a number of optical fibers, with first ends of the optical fibers arranged distributed over a plane and second ends of the optical fibers arranged distributed along a line, with the first ends facing the light emitter or, if provided, facing the homogenization device.

[0089] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, in which the same reference numerals indicate the same or corresponding parts. [Brief description of the drawings]

[0090] [Figure 1] FIG. 1 is a schematic representation of a chromatic confocal measurement setup. [Diagram 2] FIG. 2 shows a first preferred form of light source in which multiple light emitters couple light into a homogenizer. [Diagram 3] FIG. 3 shows a second preferred form of the light source, in which the light emitters are rod-shaped. [Figure 4] FIG. 4 shows a third preferred form of the light source, in which a rod-shaped illuminator illuminates a slit diaphragm. [Diagram 5] FIG. 5 shows a fourth preferred embodiment of the light source, in which the slit diaphragm is arranged at an angle to the longitudinal axis of the light emitter. [Figure 6] FIG. 6 shows a fifth preferred form of the light source, in which the rod-shaped illuminator has a mirrored front surface. [Figure 7] FIG. 7 shows a sixth preferred form of the light source, in which the light emitter is frusto-conical in shape. [Figure 8] FIG. 8 shows a seventh preferred form of the light source, in which a rod-shaped light emitter is surrounded by a parabolic groove for light collection. [Figure 9] FIG. 9 is a schematic representation of an alternative chromatic confocal measurement apparatus, additionally including a camera. [Figure 10a]FIG. 10a shows a greatly simplified and detailed schematic representation of another alternative chromatic confocal measurement setup, in which a prism generates a transversal chromatic focus shift. [Figure 10b] FIG. 10b shows a greatly simplified and detailed schematic representation of another alternative chromatic confocal measurement setup, in which a prism generates a transversal chromatic focus shift. [Figure 11] FIG. 11 shows an eighth preferred form of the light source, in which the measurement light generated by the light emitter is focused by a cylindrical lens onto an elongated exit surface. [Figure 12] FIG. 12 shows a ninth alternative configuration of the light source, in which the pump light is focused by a cylindrical lens onto a rod-shaped emitter. [Figure 13] FIG. 13 shows a tenth preferred form of the light source in which a unidirectional wedge-shaped homogenizer is used. [Figure 14] FIG. 14 shows an eleventh preferred form of the light source, in which the light emitter is plate-shaped and the pump light is incident through the side. [Figure 15] FIG. 15 shows a twelfth preferred form of the light source, in which an optical fiber receives the measurement light generated from a plate-shaped light emitter and transforms it into a line-shaped light distribution. [Figure 16] FIG. 16 shows a thirteenth preferred form of the light source, in which the light emitter is plate-shaped and the pump light enters through one of the two bottom faces. [Figure 17] FIG. 17 shows a fourteenth preferred form of the light source, in which the illuminator is frusto-conical in shape and the light is guided by total reflection inside the illuminator. [Figure 18] FIG. 18 shows a fifteenth preferred form of the light source, in which the light emitter is rod-shaped and the pump light is coupled into the light emitter via a curved cylindrical surface. [Figure 19]FIG. 19 shows a sixteenth preferred form of the light source, in which the light emitter has a double truncated cone shape. [Figure 20] FIG. 20 shows a seventeenth preferred form of the light source, in which the light emitter has the shape of a square pyramidal truncation. [Figure 21] FIG. 21 shows an eighteenth preferred form of the light source, in which the light emitter is rod-shaped and the polychromatic light emerging therefrom is guided through a homogenizer having the shape of a square pyramidal truncation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0091] 1 is a schematic representation of a chromatic confocal measuring device. The measuring device has a light source 1, which emits polychromatic measuring light 2 through a light exit surface. The measuring light 2 passes through a first confocal diaphragm 3, which has a number of point-like openings or at least one slit-shaped opening and acts as a confocal aperture. The first confocal diaphragm 3 is imaged onto a measuring object 6 by an imaging optics, which here comprises lenses 4 and 5.

[0092] In that case, at least one component of the imaging optics, here for example lens 5, brings about a chromatic focus shift, whereby light of different wavelengths at different heights is imaged along the optical axis of the imaging optics.

[0093] The measuring light 2 is reflected by the measurement object and returned through a lens 5 into the imaging optics, which for example has a beam splitter 7, which guides a part of the reflected measuring light 2 towards a first receiving and evaluating unit 8. The measuring light 2 is then imaged via a further lens 9 onto a second confocal diaphragm 10. In accordance with the chromatic confocal principle, only the light of the wavelengths that are also focused on the surface of the measurement object 6 is sharply imaged onto the second confocal diaphragm 10. The light of these wavelengths passes through the second confocal diaphragm 10 with maximum intensity.

[0094] The first receiving and evaluating unit 8 measures the intensity of the measurement light reflected from the measurement object and passing through the second confocal aperture 10 according to the wavelength and the transversal position of the reflection point on the measurement object, and based thereon determines the spacing and / or thickness of multiple points of the measurement object 6 or of an area extending in at least one spatial direction.

[0095] 2 to 8, 11 and 12 show a preferred form of the light source 1.

[0096] 2 shows a first preferred embodiment of the light source 1. The light source 1 comprises a number of pump light sources 20, e.g. laser diodes, which emit pump light 21 at a first wavelength. The pump light 21 is directed to a number of light emitters 22, which convert the pump light 21 into polychromatic light 23 by a physical process, e.g. phosphorescence, fluorescence or scintillation. The polychromatic light 23 for example comprises a spectrum of wavelengths, the wavelengths of the emission spectrum being typically larger than the wavelengths of the pump light 21. The polychromatic light 23 may preferably comprise a part of the pump light 21 in addition to the emission spectrum.

[0097] In order to obtain an approximately uniform distribution of the radiant intensity along the exit surface 24 of the light source 1, a homogenizer 25 is used. This preferably consists of a thin glass plate, which acts as an optical waveguide in one spatial direction, whereby the polychromatic light 23 is guided in a preferred manner towards the exit surface 24 and is thereby distributed approximately uniformly along the extended dimension of the homogenizer 25. This light then emerges from the light exit surface 24 as homogenized measuring light 26.

[0098] 3 shows a second preferred embodiment of the light source 1. The exemplary light source 1 comprises a pump source 30, e.g. a laser diode, which emits pump light 31 of a first wavelength. The pump light 31 is directed towards a rod-shaped phosphor 32, which converts the pump light 31 into polychromatic light 33 by a physical process, e.g. phosphorescence, fluorescence or scintillation.

[0099] In that case the pump light 31 preferably enters through the bottom surface 34 of the rod-shaped light emitter 32. This has the advantage that as much of the pump light 31 as possible is converted, since it passes through the entire rod along its length.

[0100] As the measurement light, light 33 emitted from the side surface of a rod-shaped light emitter 32 is used.

[0101] Due to the nature of the physical processes (e.g. phosphorescence, luminescence or scintillation), light is usually not emitted uniformly along the length of the rod-shaped luminophore. This is shown in FIG. 4. Typically, most light 35 is emitted close to the entrance surface, where the emission decreases exponentially over the length, as shown by the diagram line 36. Furthermore, the emission is approximately homogeneous in all spatial directions and is not only directed towards the exit surface used. The view from the front surface 37 shows the radial radiation distribution. To ensure light emission only along the desired light exit surface, for example a slit diaphragm 38 is used. The direction of the longer extent of the opening then corresponds to the length direction of the rod-shaped luminophore 32.

[0102] Several advantageous possibilities are then presented for concentrating the light in the direction of the exit surface of the light source and homogenizing it in the direction of its longitudinal extent. The individual measures can preferably be combined with one another.

[0103] 5 shows a preferred possibility of this kind. Here, a slit diaphragm 58 is used, which is inclined with respect to the longitudinal axis of the rod-shaped light emitter 32. In that case, the slit diaphragm 58 is located further away near the entrance face 34 of the light emitter 32 than near the opposite front face, so that a smaller proportion of the light emitted near the entrance face 34 passes through the diaphragm, at least partially compensating for the higher emission.

[0104] 6 shows another preferred embodiment for homogenization, in which the front surface 37 of the rod-shaped light emitter 32, opposite the entrance surface 34, is formed as a mirror, so that the pump light 31, which passes completely through the light emitter 32, is reflected there and passes back again in the opposite direction. The emissions along the forward and return paths are partially complementary, so that the intensity differences are partially compensated.

[0105] 7 shows another preferred embodiment for homogenization. In this case, the light emitter 72 is formed as a truncated cone. In this case, the front surface 77 opposite the entrance surface 74 is formed smaller than the entrance surface 74. Due to the high refractive index, the light emitter 72 serves as a waveguide for the pump light 31, so that the pump light 31 is concentrated due to the reduction in cross section when passing through the light emitter 72. This increases the emission per unit volume along the section, which at least partially compensates for the reduced emission. The reduction in cross section counteracts the falloff of the pump light power along the section, so that the pump light intensity is maintained at a uniform level.

[0106] 8 shows another preferred embodiment of the light source 1 for homogenizing and concentrating light. The light source 1 then comprises a parabolic mirror 89. The parabolic mirror is arranged in such a way that at least a part of the light leaving the rod-shaped light emitter 32 in a direction different from the slit diaphragm 38 is reflected towards the slit diaphragm. The parabolic mirror 89 is preferably a parabolic groove, i.e. a parabolic shaped groove. In a cross section guided perpendicularly to the groove axis, the concave boundary line is a parabola. The groove axis is preferably parallel to the axis of the light emitter 32.

[0107] In a preferred variant, the cross section of the parabolic groove varies over its length, in particular the groove is of different depth at various points, for example deeper at one end than at the other end, or deeper in the centre than near the ends.

[0108] 9 shows an alternative chromatic confocal measurement arrangement in a schematic representation, which essentially corresponds to the measurement arrangement shown in FIG. 1, with the exception that a second beam splitter 97 is arranged between the first beam splitter 7 and the first receiving and evaluating unit 8. This second beam splitter 97 guides a part of the measuring light 2 reflected from the measurement object 6 to a second receiving and evaluating unit 98.

[0109] For example, the second receiving and evaluating unit 98 is a unit providing an image, preferably a camera.

[0110] The chromatic confocal measuring device of Figures 10a and 10b has, like that of Figure 1, a light source 1, a first confocal diaphragm 3 and an imaging optics consisting of lenses 4 and 5 and an additional optical element 101 formed as a prism, by means of which the measuring light 2 is guided onto the measurement object 6. The confocal diaphragm 8 is formed here as a slit diaphragm, the slit direction being perpendicular to the drawing plane.

[0111] The axis of symmetry of the lens 5 is then arranged obliquely to the average surface normal of the measurement object. The imaging optics is designed in such a way that in addition to the chromatic aberrations along the axis of the imaging optics, a pronounced transversal chromatic focus shift also occurs. This is preferably provided by the additional optical element 101.

[0112] Thereby, the measuring light 2 reflected from the measuring object 6 is received at an angle by a second imaging optics consisting of lenses 105 and 109 and an optical element 102. The second imaging optics is preferably designed mirror-symmetrically to the first imaging optics.

[0113] Similar to the embodiment of FIG. 1, the measuring device comprises a second confocal aperture 10 and a first receiving and evaluating unit 8 .

[0114] 11 shows another preferred form of light source 1. The example light source 1 comprises a pump source 120, e.g. a laser diode, which emits pump light 121 at a first wavelength. The pump light 121 is directed onto a phosphor 122, which converts the pump light 121 into polychromatic light 123 by a physical process, e.g. phosphorescence, fluorescence or scintillation. For example, the polychromatic light 123 has a spectrum of wavelengths, the wavelengths of which are typically greater than the wavelengths of the pump light 121. The polychromatic light 123 preferably also comprises a portion of the pump light 121.

[0115] To guide the light 123 to the elongated exit surface, the light is first collimated using a preferably aspheric lens 124 and passes through a subsequent cylindrical lens 125, which focuses the light again onto a line segment. A gap stop 126 is preferably arranged at the location of the focusing line, whose gap opening forms the elongated exit surface of the light source 1.

[0116] 12 shows another preferred embodiment of the light source 1. The example light source 1 comprises a pump source 130, e.g. a laser, which emits pump light 131 of a first wavelength. The pump light 131 is first collimated by an aspheric lens 134 and then focused onto a linear segment by a cylindrical lens 135. At the location of the focused line, a light emitter 136 is arranged, which converts the pump light 131 into polychromatic light 137 by a physical process, e.g. phosphorescence, fluorescence or scintillation.

[0117] 13 shows another preferred form of light source 1. The example light source has a pump light source 210 that directs pump light 211 onto a waveguide 212 that guides a portion of the pump light onto a wedge-shaped light emitter 215 so that the pump light impinges on the entire input face of the light emitter.

[0118] The light emitter 215 is configured to convert the pump light into polychromatic light 213 and act as a waveguide for the polychromatic light. The light emitter is configured in a wedge shape in two spatial directions, where the two spatial directions are orthogonal to the light propagation direction. An example of a light beam is shown in Figure 13, which shows the geometric path of the polychromatic light.

[0119] The light which travels in the light emitter 215 at a large angle to the direction of propagation abuts against one of the side faces. Due to the wedge shape of the waveguide, the light travels further after reflection at a smaller angle to the direction of propagation. The light emitter is formed in such a way that the side length of the exit surface in one spatial direction corresponds to the desired side length of the light exit surface 214 in the spatial direction along which the light exit surface extends only slightly.

[0120] The polychromatic light further propagates in a second wedge-shaped waveguide 216, which is wedge-shaped in only one spatial direction. The angle of the light with respect to the propagation direction in one spatial direction is further flattened by reflection at the side surfaces. The second waveguide is formed such that the side length at the light exit surface corresponds to the side length of the light exit surface, which is expanded.

[0121] Due to the wedge shape of the waveguide, the polychromatic light leaves the light exit surface at a small aperture angle, so that the final aperture of the measuring device is sufficient to make the light available as measuring light over the entire range.

[0122] 14 shows another preferred form of light source 1. The example light source 1 comprises a pump source 150, e.g. a laser diode, which emits pump light 151 at a first wavelength. This pump light is directed towards the side of a plate-shaped light emitter 154.

[0123] For this purpose, the pump light is first collimated by a collimation optic 152 and then focused in a direction in which the plate-shaped light emitter has a small extent by a cylindrical optic 153. Focusing in one direction ensures that the distribution of the pump light on the input surface is approximately homogeneous and that the largest possible part of the pump light generated by the pump source can be coupled into the light emitter.

[0124] The illuminator converts the pump light into polychromatic light 155. A part of the polychromatic light generated in the plate-shaped illuminator, possibly after being reflected at one of the bottom faces or at one of the side faces, impinges on the side opposite to the entrance face of the pump light and leaves the illuminator through this side.

[0125] In order to increase the yield of the measurement light, the bottom surface and the side surfaces not used as light exit surfaces can be formed with a mirror finish.

[0126] 15 shows another preferred embodiment of the light source 1. The light source here comprises a number of pump light sources 160, e.g. LEDs, positioned along a line and generating pump light 161. The line of pump light sources is imaged by imaging optics 166 onto a plate-shaped light emitter 164, the side of which is used as the entrance surface for the pump light.

[0127] The line along which the pump light sources are then arranged is parallel to the direction of extension of the incidence surface, so that an approximately homogeneous illumination of the incidence surface is obtained. In a preferred manner, the imaging optics is formed such that the extension of the LEDs in one direction is perpendicular to the line direction, comparable to the thickness of the plate-shaped emitter.

[0128] For example, 1:1 imaging is effective if the LED width is 200 μm and the plate has a thickness of 200 μm. The aperture of the imaging optics is kept as large as possible, thereby allowing as much pump light as possible to be coupled into the plate-shaped emitter.

[0129] In an alternative embodiment, the linear arrangement of pump light sources can be attached directly to the side of the plate-shaped light emitter, so that the pump light can be coupled into the plate-shaped light emitter without imaging optics.

[0130] The light source shown in FIG. 15 includes multiple fibers 167, each having a first fiber end 168 that receives polychromatic light 23 that is emitted from the light emitter through one of the sides.

[0131] The fibers each have a second fiber end 169, where the second fiber end delivers polychromatic light 165. The second fiber ends are arranged in a line and form a light exit surface.

[0132] Polychromatic light capture, which exits the emitter through more than one side, increases yield.

[0133] 16 shows another preferred embodiment of the light source 1. The exemplary light source 1 comprises a planar pump light source 170, which here is formed as an array of LEDs spread out in two sections.

[0134] Pump light 171 generated by a pump light source enters through a first bottom surface of a plate-shaped illuminator 174 and generates polychromatic light 175, which exits the illuminator through one of the side surfaces. A second bottom surface of the illuminator can be formed as a mirror, so that the pump light can still contribute to the generation of polychromatic light after reflecting off the second bottom surface.

[0135] Figure 17 shows another preferred form of light source 1. The example light source comprises a pump source 180, e.g. a laser diode, which emits pump light 181 at a first wavelength. This pump light is directed by imaging optics 182 onto the ceiling surface of a light emitter 183, which has the shape of a truncated cone.

[0136] The light source has a number of optical fibers 184, each having a first fiber end 185, which are positioned in a planar arrangement near the bottom surface of the light emitter to receive the polychromatic light generated by the light emitter, and the optical fibers each having a second fiber end 186, which are arranged in a line to transmit the polychromatic light 187, and together form the light output surface of the light source.

[0137] The light emitter is formed in the shape of a truncated cone to minimize the proportion of light that strikes the first fiber end at too steep an angle and therefore cannot be coupled into the fiber.

[0138] 17 shows an example of a light beam representing the geometric path of fluorescent light, which is generated by a light emitter and has a large angle with respect to the axis of symmetry of the truncated cone. By successive reflections on the inside of the jacket surface of the truncated cone, the angle between the light beam and the axis of symmetry of the truncated cone gradually decreases, especially as far as the light can be coupled into the fiber end.

[0139] The planar arrangement of the fiber ends can be formed in such a way that the area through which the polychromatic light passes, particularly the bottom surface, is covered as completely as possible, so that as large a portion of the light as possible can be coupled into the fiber and guided further.

[0140] Figure 18 shows another preferred form of the light source 1. The example light source comprises a pump source 190, e.g. a laser diode, which emits pump light 191 of a first wavelength. The light source further comprises a cylindrically shaped light emitter 193.

[0141] The cylindrical illuminator has an entrance window 198 through which pump light can be coupled into the illuminator. If the pump light is focused to the height of the entrance window, the extent of the entrance window can be kept very small. For example, an entrance window extent of 10 μm can be sufficient.

[0142] The pump light can then be coupled in such a way that it strikes the inner jacket surface at a flat angle and is totally reflected. This behavior is repeated for successive reflections on the inner jacket surface, so that the pump light is forced to follow a spiral track inside the cylindrical emitter.

[0143] The preferably cylindrically shaped illuminator is shaped such that the pump light contributes mostly to the generation of polychromatic light on its route along a spiral track from the entrance window to the bottom surface of the cylinder. For a typical average free route length of the pump light in a illuminator of 200 μm, this is ensured for a track length of, for example, 1 mm.

[0144] The cylindrical emitter can then be realized very compactly and at the same time provide a sufficiently large track length for the pump light: for example, the cylinder can have a radius of 25 μm and the pitch height of the spiral track can be 20 μm (which ensures that in the case of an entrance window spread of 10 μm, the pump light does not leave the cylindrical emitter through the entrance window again after the first round).

[0145] In that case, if the height of the cylinder is 150 μm, the pump light can make 6 revolutions on the route from the entrance window to the bottom surface 6 and therefore travel a route length of more than 1 mm.

[0146] Polychromatic light 197 is emitted from the light emitter through the jacket surface and the bottom surface in all spatial directions. The light source comprises a number of fibers, each having a first fiber end 195, which are arranged on a surface partially surrounding the light emitter. Preferably, these fiber ends are packed as tightly as possible in order to receive and further guide as large a portion of the polychromatic light as possible.

[0147] The second fiber ends of the fibers are arranged in a line and form an elongated light output surface.

[0148] 19 shows another preferred form of the light source 1. The example light source comprises a light emitter 203 formed in the shape of two truncated cones joined at their bases. Pump light 201 is coupled into the light emitter through an entrance window 208, where the pump light is forced to trace a spiral track by successive total reflections within the light emitter and generates polychromatic light 207.

[0149] Depending on the opening angle of the cones, the track height of the pump light gradually decreases on its route from the entrance window in the first cone to the top surface, until the pump light travels back to the bottom surface, where it continues further in the second cone, where the behavior is repeated.

[0150] This form of phosphor allows a large route length of the pump light within the phosphor with a very compact structure, thus allowing the use of photoluminescent materials with half-maximum lengths greater than 1 mm, such as highly transparent phosphorus-doped glass materials, which are advantageous compared to single crystals due to their heat resistance, ease of processing, and the generation of broadband and uniform bright spectra.

[0151] Figure 20 shows another preferred embodiment of the light source 1, which substantially corresponds to the light source shown in figure 17. The exemplary light source comprises a pump source 310, for example a laser diode, which emits pump light 311 of a first wavelength. The pump light 311 is directed by imaging optics 312 onto a light emitter 313, which in this embodiment has the shape of a square pyramid truncation, through whose top surface the pump light 311 is coupled. The cross section of the light emitter 313 is therefore square, which increases continuously with increasing distance from the top surface to the base of the truncation. The sides of the truncation are mirrored, so that no light can be emitted to the outside via the sides.

[0152] In this embodiment the bottom surface is adjacent to the rectangular side of the glass square which forms the homogenizer 314. If the length of the light emitter 313 is sufficient, the homogenizer 314 can be omitted.

[0153] The light source 1 further comprises a transformer formed of a number of optical fibers 315. First fiber ends of the fibers 315 are arranged planarly near the other rectangular side of the homogenizer 314 and receive the polychromatic light generated by the light emitter and further guided by the homogenizer 314. Second fiber ends of the optical fibers 315 are arranged along a line and together define a line-shaped output surface 316 of the light source 1.

[0154] The pyramidal trapezoidal shaped illuminator 313 abuts the first fiber end of the optical fiber 315 at too steep an angle and thus minimizes the proportion of light that cannot be coupled into the fiber 315. Compared to the conical shape of the illuminator, as shown in Fig. 17, the pyramidal shape has the advantage that it is easier to form from luminescent material that is often difficult to process. Moreover, it has been surprisingly found that the pyramidal shape results in a more uniform intensity distribution at the base of the illuminator. In rotationally symmetric illuminators, there is usually an undesirable concentration of polychromatic light on the axis of symmetry.

[0155] 20, a light beam is suggested by dashed lines representing the geometric path of the fluorescent light, which is generated by the light emitter 313 and is initially at a large angle to the axis of symmetry of the truncated pyramid. By successive reflections on the inside of the jacket surface of the truncated pyramid, the angle between the light beam and the axis of symmetry of the truncated pyramid is reduced, and finally the light can be coupled with little loss into the end of the optical fiber 315.

[0156] Apart from reasons of clarity, the planar arrangement of the fiber ends can in particular be formed so that the part of the bottom surface of the homogenizer 314 (or, in its absence, the light emitter 313) through which the polychromatic light passes is covered as completely as possible, so that as much of the light as possible can be coupled into the fiber 315 for further guidance.

[0157] FIG. 21 shows another preferred form of light source 1, which incorporates elements of the embodiments shown in FIGS.

[0158] The exemplary light source comprises a pump source 320, e.g. a laser diode, which emits pump light 321 of a first wavelength. The pump light 321 is directed by imaging optics 322 towards the front surface of a rod-shaped light emitter 323. In this embodiment the rod has a circular cross-section. However, oval, square, rectangular or other regular or irregular polygonal cross-sections are also conceivable. The side surfaces of the light emitter 323 are mirrored so that no light can be emitted to the outside via the side surfaces.

[0159] The other front surface of the rod-shaped light emitter 323 is adjacent to the square ceiling surface of the homogenizer 324, which in this embodiment is made of glass and has the shape of a pyramidal base. The homogenizer has a square cross section that increases continuously as its distance from the light emitter 323 increases, down to the base of the pyramidal base.

[0160] The light source 1 further comprises a modification device, which is again formed by a number of optical fibers 325. First ends of the fibers 325 are arranged planarly near the square base of the homogenizer 324 and receive the polychromatic light generated by the light emitters and further guided by the homogenizer 324. Second ends of the optical fibers 325 are arranged along a line and together define a line-shaped exit surface 326 of the light source 1.

[0161] The homogenizer 324 abuts the first end of the optical fiber 325 at too steep an angle and therefore reduces the percentage of light that cannot be coupled into the fiber 325 .

[0162] With respect to the embodiment shown in Fig. 20, the light source 1 shown in Fig. 21 has the advantage that the geometry of the light emitter 323 can be defined from the viewpoint of being particularly easy to form. In contrast, the more complex, but very favorable geometry of the pyramidal homogenizer 324 with respect to homogenization and coupling into the fiber end is easily realized from glass material. Also in this embodiment, the transformation of the polychromatic light into a line-shaped exit surface 326 is taken over by the transformation device formed by the optical fiber 325.

[0163] Important aspects of the present invention are summarized in the following passages: 1. A chromatic confocal measuring device for measuring the distance and / or thickness of multiple locations on a measurement object simultaneously or of an area extending in at least one spatial direction, comprising: A light source (1) is provided, the light source emitting a polychromatic measurement light (2) through a light exit surface, at least one first confocal aperture (3, 10) through which the measurement light passes, the first confocal aperture (3, 10) having a plurality of point-like openings or at least one slit-shaped opening, an imaging optics (4, 5, 101) arranged to effect a chromatic focus shift of the measurement light and to image the second confocal aperture (3) into the measurement volume, in which different wavelengths are focused at different heights, a first receiving and evaluating unit (8) which is designed to measure the intensity of the measuring light reflected from the measuring object as a function of the wavelength and the transversal position of the reflecting points on the measuring object and to determine the spacing and / or thickness of a plurality of points or areas extending in at least one spatial direction of the measuring object (6), In things, A chromatic confocal measurement apparatus, characterized in that the light source (1) is a laser-pumped phosphor-based light source and the exit surface (24) is elongated. 2. A measuring device as described in paragraph 1, characterized in that the light source (1) has at least one pump source (20), which emits and directs pump light (21) onto a light emitter, which converts the pump light (21) into polychromatic light (23). 3. A measuring device according to sentence 2, characterized in that the polychromatic light (23) then passes through a homogenizing device (25; 324) in such a way that the intensity of the light (26) emerging from the exit surface (24) is at least approximately uniformly distributed. 4. A measuring device as described in sentences 2 or 3, characterized in that the light-emitting body (32) is rod-shaped, in which case the light (3) emitted through the side of the rod-shaped light-emitting body (32) is used as the measuring light. 5. A measuring device according to paragraph 4, characterized in that the light source (1) has a slit diaphragm (38), in which case the slit of the slit diaphragm (38) is the light exit surface of the light source (1). 6. A measuring device as described in paragraph 5, characterized in that the slit diaphragm (58) is inclined with respect to the longitudinal axis of the rod-shaped light emitter (32). 7. A measuring device described in any one of paragraphs 4 to 6, characterized in that the front surface (37) of the rod-shaped light-emitting body (32) opposite the incident surface (34) through which the pump light (31) enters the light-emitting body (32) is formed as a mirror surface. 8. A measuring device according to any one of paragraphs 4 to 7, characterized in that the light source (1) has a parabolic mirror ((89)). 9. A measuring device according to sentences 2 or 3, characterized in that the light emitter is plate-shaped. 10. A measuring device according to paragraph 9, characterized in that the light emitter is arranged as follows: the pump light enters the light emitter through one side and the measurement light exits the light emitter on the opposite side. 11. A measuring device as described in sentence 10, characterized in that the light emitter forms a wedge angle between 1° and 10° along a side perpendicular to the side through which the pump light enters. 12. A measuring device according to sentence 9, characterized in that the light emitter is arranged as follows: the pump light enters through one of the two bottom surfaces of the light emitter and the measurement light exits from a side surface of the light emitter arranged perpendicular to the bottom surface. 13. A measuring device according to any one of paragraphs 1 to 12, characterized in that the light source has a deformation device, which is arranged to deform the light distribution so that the cross section of the light distribution becomes more vertical. 14. A measuring device according to paragraph 13, characterized in that the deformation device has an arrangement of optical fibers. 15. A measuring device according to any one of paragraphs 2 or 3, characterized in that the deformation device has a truncated conical section. 16. The section has a curved jacket surface, the jacket surface is mirrored, and The sections are arranged as follows: the pump light enters the emitter through the ceiling surface of the truncated cone; A measuring device according to document 14, characterized in that 17. A measuring device according to any one of sentences 2 or 3, characterized in that the light emitter has a cylindrical section, which section is arranged as follows: the pump light coupled through the cylindrical jacket surface is retained within the section by total reflection. 18. A measuring device according to any one of sentences 2 or 3, characterized in that the light emitter (213) has a section with the shape of a preferably square pyramidal base, which section is arranged so that the pump light enters the light emitter (213) through the ceiling surface of the pyramidal base. 19. The measuring device described in paragraph 18, characterized in that several sides of the pyramid base are mirrored. 20. A measuring device according to sentences 18 or 19, characterized in that a homogenizing device (225) is arranged adjacent to the base of the pyramid base. 21. The measuring device according to sentence 20, characterized in that the homogenizer (225) is square-shaped. 22. A measuring device according to any one of documents 18 to 21, characterized in that it comprises a deformation device, which has a number of optical fibers (214), in which the first ends of the optical fibers (214) are arranged distributed over a plane and the second ends of the optical fibers are arranged distributed along a line. 23. A measuring device according to any one of sentences 1 to 22, characterized in that the measuring device has a second receiving and evaluating unit (98), which is configured to detect an image of the measuring object (6). 24. A measuring device according to any one of sentences 1 to 23, characterized in that the measuring device has a second imaging optical system (105, 102, 9) formed spatially separated from the first imaging optical system (4, 101, 5), in which the first imaging optical system and the second imaging optical system each have additional optical elements (101, 102) which bring about a chromatic focus shift in the transverse direction relative to the optical axis of the lens (5, 105) of the respective imaging optical system. 25. A measuring device as described in sentence 24, characterized in that the first imaging optics is arranged to form focal points of different wavelengths at different locations, where these locations are along a line segment that forms an acute angle with respect to the optical axis of the lens (5) of the first imaging optics (4, 101, 5).

Claims

1. A chromatic confocal measuring device for measuring the distance and / or thickness of a plurality of locations on a measuring object simultaneously or of an area extending in at least one spatial direction, comprising: The present invention relates to a laser-pumped phosphor-based light source (1), which emits polychromatic measurement light (2) through a light exit surface, the light source (1) having at least one pump source (20), which emits and directs pump light (21) onto a phosphor, which converts the pump light (21) into polychromatic light (23), at least one first confocal aperture (3, 10) through which the measurement light passes, the first confocal aperture (3, 10) having a plurality of point-like openings or at least one slit-shaped opening, an imaging optical system (4, 5, 101) arranged to effect a chromatic focus shift of the measurement light and to image the first confocal aperture (3) into the measurement volume, in which different wavelengths are focused at different heights; a first receiving and evaluating unit (8) which is adapted to measure the intensity of the measuring light reflected from the measuring object as a function of the wavelength and the transversal position of the reflection points on the measuring object and to determine based thereon the spacing and / or the thickness of a plurality of points or areas extending in at least one spatial direction of the measuring object (6); In things, the light source has a vertical exit surface (24) that is at least an order of magnitude longer in a vertical direction relative to the vertical exit surface than in a horizontal direction relative to the vertical exit surface; Chromatic confocal measurement device, characterized in that the polychromatic light (23) passes through a homogenization device (25; 225; 314; 324) so ​​that the intensity of the light (26) emerging from the elongated exit surface (24) is at least approximately uniformly distributed.

2. 2. The measurement device according to claim 1, characterized in that the homogenizer (225) has a section having the shape of a pyramidal base, said section being arranged such that the polychromatic light enters said section through a ceiling surface of the pyramidal base.

3. 3. The measuring device according to claim 2, characterized in that the sides of the pyramid base are inclined in such a way that the polychromatic light guided in said sections is guided by total reflection in the homogenizer (225).

4. 4. The measuring device according to claim 1, wherein the light emitter (174) is plate-shaped.

5. 4. The measuring device according to claim 1, wherein the light emitter (183) has a frustoconical section.

6. the frusto-conical section has a curved jacket surface, the jacket surface being mirrored; and the truncated cone-shaped section is arranged such that pump light enters the light emitter (183) through a ceiling surface of the truncated cone.

6. The measuring device according to claim 5.

7. 4. The measuring device according to claim 1, wherein the light emitter (313) has a section with the shape of a pyramidal base, the section being arranged such that the pump light enters the section through a ceiling surface of the pyramidal base.

8. 8. The measuring device according to claim 7, characterized in that the side surfaces of the pyramid base are mirror-finished.

9. 9. The measuring device according to claim 7 or 8, characterized in that a homogenizing device (314) is arranged adjacent to the base of the pyramid base.

10. 10. The measuring device according to claim 1, wherein the light source comprises a deformation device, the deformation device being arranged to deform the light distribution so that the cross section of the light distribution becomes more elongated.

11. 11. Measuring device according to claim 10, characterized in that the deformation device comprises an arrangement of optical fibers (224; 315).

12. 12. The measuring device according to claim 1, further comprising a second receiving and evaluating unit (98), the second receiving and evaluating unit being configured to detect an image of the measuring object (6).

13. 13. The measuring device according to claim 1, characterized in that the measuring device has a second imaging optical system (105, 102, 9), which is formed spatially separated from the first imaging optical system (4, 101, 5), and in which the first imaging optical system and the second imaging optical system each have additional optical elements (101, 102), which optical elements bring about a chromatic focus shift transversely to the optical axis of the lens (5, 105) of the respective imaging optical system.

14. 14. The measuring device according to claim 13, characterized in that the first imaging optics is arranged to form focal points of different wavelengths at different locations, said locations being arranged along a line segment forming an acute angle with respect to the optical axis of the lens (5) of the first imaging optics (4, 101, 5).

Images