Chromatic confocal high-speed measurement method and scalable device for implementing the method

Abstract

An extremely fast optical measurement method combines a chromatic confocal distance measurement with a chromatic confocal color measurement of a partially reflective test surface. A corresponding measuring device uses at least two monochromatic emitters, particularly single- or multi-mode laser diodes, as a light source.

Description

Field of the InventionThe invention relates to a method and a size-scalable device for the extremely fast, contactless measurement of physical properties of an at least partially reflecting optical boundary surface of an object, in particular for the point measurement of the distance and the color, in order to create topographical maps of the object surface from this, in the case of moving objects, or to configure them as monitoring by correlative comparison with a previously stored reference.Prior ArtThe basic measurement principle of the invention presented here, both in the area of distance measurement and in the area of simultaneous detection of the color, is that of chromatic confocal microscopy, wherein here an innovation consists in that substantial system advantages have been obtained from the use of system components which would otherwise be completely unsuitable for the previously known implementations of the chromatic confocal measurement principle.The first approaches have already been presented, inter alia, in U.S. Pat. No. 3,013,467 A (1961, M. Minsky) and in "FOCUS-WAVELENGTH ENCODED OPTICAL PROFILER" by G. Molesini et al. (OPTICS COMMUNICATIONS, volume 49, number 4, 1984). The first modern, industrially available distance measuring devices based on this measuring principle were known from FR 2 738 343 A1 (1995, Josephson Sabban) or from the article by M. Jurca et al. (1997, Sensor Magazine No. 4 / 97, pages 15-18, "An alternative to the laser").In the meantime, very many process variants have been developed, which cannot be mentioned here in particular completely, the physically required features which arise from the rigorous implementation of the chromatic confocal measurement principle being summarized below.Such a point distance measuring device consists of: a) a polychromatic incoherent light source, b) an objective having an increased axial chromatic aberration, called "chromatic objective" or "hyperchromate" in the technical literature, c) a very small aperture, usually round, for realizing the confocal measuring arrangement which transmits both the polychromatic light of the light source a) in the direction of the objective and the measuring point on the object surface and the resulting back reflection from the object surface in the measuring point in the opposite direction, d) a device for separating the back reflection from the polychromatic light of the light source, e) a spectrally resolving light intensity measuring device for analyzing the back reflection, wherein the spectrally resolving light intensity measuring device measures each of the monochromatic wavelengths used separately; In particular, it can comprise a low-noise photodiode coupled directly or via an optical fiber for the detection of each of the monochromatic wavelengths used.The polychromatic light (a) is focused through the aperture (c) by the chromatic objective (b) so that all the individual wavelengths of the polychromatic light are distributed linearly on the optical axis of the objective between the focal length Z B( for the shortest wavelength of the polychromatic light) and the focal length Z R( > Z B) ( for the longest wavelength of the polychromatic light), according to the course of the longitudinal chromatic aberration of the objective. "B" here correspondingly stands for blue and "R" for red. When the focused polychromatic light is on an optical interface at a distance Z OBJ( Z B< Z OBJ< Z R) a point reflection having the wavelength λ OBJ, is produced and substantially only at this wavelength λ B< λ OBJ< λ R reflected light passes back through the objective and through the (point) aperture conjugated to the object focal point, in order to be separated by the device (d) and fed to the measuring device (e). The small aperture (c) functions as a spatial filter that transmits the light scattered back from the object only from the immediate axial and lateral environment of Z OBJ. All other light is filtered away spatially by the receiving aperture-resulting in the high measurement resolution of the method.The facts presented have a whole series of obligatory sequences, for example the measurable back reflection intensity depends on the convolution of the diffraction integral with the aperture with the PSF (point spread function) of the objective, which in turn depends mainly on the NA (numerical aperture) of the objective, so that there is the comprehensible desire to have an NA which is as high as possible, since this leads to an improvement in the measurement resolution which can be achieved. For the same reason, the diameter of the aperture is kept small. Likewise, the chromatic objective usually has four to six lenses in order to produce a focus which is as small as possible, free of spherical aberrations. The following variants of the chromatic objective are known:b1. b1. b1. Multi-lens hyperchromate which focuses the aperture directly on the object,b2. b2. Combination of a collimating lens (achromate) with a multi-lens hyperchromate,b3. b3. b3. Use of a single Fresnel lens as a hyperchromate (similar to b1),b4. Use of a lens combination with a Fresnel lens (similar to b2),b5. Use of a grade index lens (similar to b1),b6. Use of a lens combination with a grade index lens (similar to b2).Variants b3 to b6 usually result in larger focal spot diameters in comparable arrangements.It will also be understood that the light source may be non-monochromatic, or may be comprised of multiple monochromatic sources, since each monochromatic source would focus from the objective into a single point and distance between two adjacent such points would not be able to be measured.A few variants are known as polychromatic light source: a1. Halogen lamp, a2. High-pressure lamp, a3. LEDs or SLEDs (super-luminescent-emitting diodes), a4. Laser-generated continuous spectrum.The incoherent light of the polychromatic light source represents one of the most important reasons of the versatile restrictions of the method, in particular the measurement speed, the maximum available light power and the SNR value (signal noise ratio) limited thereby.The separating device of the back reflection is offered mainly in two variants:d1. d1. As a "Y" or "X" shaped splice coupler, degree index optical fiber splice couplers,d2. d2. Using optical macro components such as beam splitters or beam splitter cubes, filters, pinhole apertures, etc.The measuring device is usually an optical spectrometer, wherein the wavelength-moderate position of the reflex is determined with a CCD line (charge-coupled device). This also represents, in most cases, the limiting measuring speed factor.DE 10 2008 029 459 B4 and WO 2009 / 153 067 A2 (2008, M. Jurca) disclose a replacement of the spectral measuring device (d), in the form of a single photodiode, and the use associated therewith of two LEDs switched on alternately as polychromatic light source, wherein the emission spectra of the two LEDs partially overlap. The method presented is very simple and above all very much faster (several orders of magnitude) due to the omission of the optical spectrometer.All known measuring methods and devices which directly, without a relative movement between measuring device and measuring object during a measuring process, have an imaging output of the measurement data as a target, or those which assume Fourier processing of the measurement data on the basis of the interferometer structure of the measuring device, have not been taken into account here because they do not compete with the present invention. Likewise, no laser measurement methods were taken into account which are not based on the chromatic confocal measurement principle.DE 10 2004 022 454 A1 describes an optical measuring device for measuring the shape or roughness of a workpiece, for which purpose a difference signal from two photoreceivers which are assigned to different focal points is evaluated. DE 10 2006 026 775 A1 discloses a device with a plurality of LEDs as polychromatic light source for illuminating a surface to be examined via an optical fiber and a focusing element, wherein reflected light reaches a beam splitter via the focusing element and the optical fiber, which beam splitter directs the light to be detected via a dispersion element to a detector unit. DE 20 2019 103 527 U1 describes an optical measuring device with a confocal-chromatic optical sensor. U.S. Pat. No. 5,785,651 A discloses a confocal-measuring microscope, wherein a plurality of lasers are used as polychromatic light source and a chromatic objective suitable for this purpose is used.Summary of the InventionThe object of the invention is to provide a method and an apparatus for the fastest possible, simultaneous contactless measurement of the distance and the color to a partially reflecting optical boundary surface, which are capable of changing the chromatic confocal measurement principle of the distance to a point on the surface to be measured in such a way that the use of a plurality of monochromatic light sources, instead of the polychromatic light sources otherwise required, is made possible, so that, owing to the much higher available and usable light power, much better signal-to-noise ratios can be achieved at considerably higher measurement speeds than with the known methods, and whereby the apparatuses for carrying out the method are (almost) arbitrarily scalable and at the same time make it possible to record the color of the measurement object.The object is achieved by the subject matters of the independent claims.A method according to the invention, which achieves the aforementioned object, has the following steps: a) generating multi-spectral light (110), consisting of two or more monochromatic light sources (101 a, b, c) which are operated in pulsed or continuous mode, for example three (e.g. RGB laser diode module), with emission wavelengths which are spaced apart from one another by 40-120 nm and which are controlled in terms of power and temperature in such a way that the ratios of the powers of the monochromatic light sources are held actively constant [via feedback alternative 1 (module 200), alternative 2 (300) or alternative 3 (400)], b) coupling the light (110) into an arm of a 2:1 - Y fiber coupler (30) via an optomechanical plug-in device (107 and 36), wherein the optical fiber (32) is designed as both a graded index or preferably step index multimode fiber or multimode circuit, and preferably has a relatively large core diameter of 50-200 μm, which is in sharp contradiction (both above. Fact) to the already known devices, wherein the common output fiber is coupled via an FC / APC fiber plug (35 and 803) into the chromatic measurement objective #1 (800), (wherein FC / APC is a fiber connector with angled physical contact, referred to as an increase of return loss), c) focusing the multi-spectral light via the chromatic measurement objective #1 (800) with small numerical aperture (NA), preferably 0.03 to 0.15, via a simple combination of optical components (801), preferably two coaxial and spatially separated (801a, b) which together have an increased longitudinal chromatic aberration (which is in contradiction to the already known devices, since such an objective usually has the largest possible NA and requires 5-6 lenses for the enlarged longitudinal chromatic aberration), so that the smallest possible loci of the individual monochromatic light sources lie at different distances on the optical axis of the objective (between the focal planes 11 and 12, after the beam deflection by the beam splitter 15), wherein the back reflection from an object surface (focal plane 10) lying between the loci of the smallest and the largest monochromatic light sources used can be detected back via the objective and the Y-fiber coupler at its second arm (33) with the measuring module (500), wherein the design of the objective in conjunction with the Y-fiber coupler ensures that, despite the large wavelength distance between two adjacent monochromatic light sources, the Bessel function-moderate axial optical path, In the preferred embodiment, the optical characteristics of the monochromatic reflex elements are partially overlapped in terms of power (here called "bell curves"), d) deflecting the focused measurement beam from the chromatic objective #1 (800), preferably by 90°, onto the object surface to be measured with the aid of a slightly wedge-shaped, antireflection-coated beam splitter (15), which has a reflection / transmission ratio of at least 50 or more %, so that a corresponding part of the light reflected by the object passes through the beam splitter into a second, identical chromatic unit of optical components (601), such as that of the objective #1 (801) from step c), which unit again merges the monochromatic components of the reflex into a collimated beam and brings the chromatic components of the beam into congruence (604), so that the distance information is lost as a result of the omission of an aperture and instead the ratios of the measurable monochromatic, monochromatic, monochromatic, monochromatic, monochromatic, monochromatic, monochromatic, optical components are deflected by the beam, Reflected powers which contain colour information of the object surface and are measured with the colour measuring device (606), wherein the particular chromatic beam guidance in the region of the object surface also enables improved detection of partially translucent object surfaces, e) fast, spectrally selective (via a holographic grating 504) highly dynamic detection of the monochromatic components of the back reflection measured at the second arm of the Y-fibre coupler (33) with selected single low-noise photodiodes (509a, b, c) which have a sufficient sensitivity and reaction speed in the wavelength range of the monochromatic light sources used, f) calculation of the measurement distance from the spectrally selectively measured powers of the monochromatic back reflection components from step e), g) fast, Spectrally selective high-dynamic detection of the monochromatic components of the reflex measured coaxially behind the second chromatic combination of optical components (606), h) calculating the color information from the spectrally selectively measured powers of the monochromatic reflex components from step d), wherein the simultaneously obtained distance information is used together to evaluate the color information.In order to avoid reflections and / or etalon effects (interference effects between parallel surfaces of an optical component), the beam splitter can be designed as a wedge-shaped beam splitter, in particular with a wedge angle of 0.5°.A sensor according to the invention or a device according to the invention is configured to carry out the method according to the invention and contains the components mentioned for the method. Optionally, the sensor / the device is configured to carry out the method variants described here.In a distance measuring method according to the invention according to the principle of chromatic confocal distance measurement, a polychromatic light source is used, which consists of a plurality of single-mode or multimode, pulsed or continuous laser diodes. The light thus obtained is focused into a multimode "Y" or "X"-shaped fiber coupler which has a fiber core diameter greater than 50 μm. An output fiber of the fiber coupler is inserted into a polychromatic objective via an FC / APC fiber plug. Here, an FC / APC fiber plug refers to an angle physical contact, APC, fiber connector of 8° for enhancing return loss. The polychromatic objective consists of a collimation achromatic lens and a polychromatic combination of preferably only two optical components (in particular a refractive lens and a diffractive lens / Fresnel lens), which together form a "chromatic objective" with a small numerical aperture NA. For sufficient overlapping of the back reflection Gaussian curves, NA≤0.3 applies in particular. The ratio of the longitudinal aberration and the focal length of the polychromatic combination is between 0.15 and 0.5, and the longitudinal aberration of the polychromatic combination covers the wavelength range of the light used. A back reflection which arises passes from an optical (at least) partially reflecting surface of the object to be measured, which is usually also referred to as an "optical refractive index separating surface" and lies approximately perpendicular to the optical axis between the foci of the shortest and longest laser diode wavelength used, back into the fiber coupler via the chromatic objective and is fed via a measurement output fiber of the fiber coupler to a spectral-resolving, light power-measuring device. A single low-noise photodiode is used for the detection of each of the monochromatic wavelengths used. Low-noise photodiodes can be understood to mean Si "PIN" photodiodes or photodiodes with a noise-equivalent beam power NEP (noise-equivalent-power) ofThe above-mentioned fiber coupler is preferably designed as a "multimode circuit". An MM circuit is a "Y" fiber coupler with better separation of transmit and receive power, thus minimizing spurious back reflection from the coupler, commonly called "optical noise.". Such fiber components are known from the single-mode fiber field and are available only for a short time also for STIN fiber. Furthermore, there are no known CCM (chromatic-confocal-distance measurement) methods using a STIN fiber circulator.The indication of a measurement object surface which is "approximately perpendicular" relates to the need for the normal on the object surface to just still have to be detected by the optical aperture (diameter of the last objective lens). Thus, for a measurement on a specular surface, the maximum inclination of the object surface at the measurement point relative to the optical axis of the objective will be only 90°±arctan(NA) (e.g. for NA=0.1=>90°±5.74°). If the object surface is rather scattering, the measurement can also be carried out with greater tilts, since sufficient scattered light is detected by the objective. This boundary "approximately perpendicular" is directly dependent on the NA of the objective.Optional variants of the method according to the invention and of the sensor / device according to the invention are explained in the dependent claims and the following description. Further variants of the method result from the intended use of the described device. Conversely, the device / sensor may be configured to execute the described method processes. In particular, an electronic control device can be provided for this purpose, which is configured for controlling described light sources and detectors / measuring devices and for signal processing and signal analysis in order to implement the described processes.Brief Description of the FiguresFurther effects and features of the invention will be described below with reference to the attached schematic figures: FIG. 1 : Monochromatic back reflections obtained via a standard CCM objective of high NA (5 lenses, NA=0.45) do not overlap and therefore cannot be evaluated with the new measurement method. FIG. 2 : Monochromatic back reflections obtained via a CCM objective of low NA (2 lenses, NA=0.11), according to the new measurement method, overlap even at a 70 nm distance or 114 nm distance of the RGB (red-green-blue) wavelengths shown here by way of example. FIG. 3 a) : Schematic overview of a sensor according to the invention, comprising the distance sensor "sensor D" 800, color sensor "sensor F" 600, beam splitter 15 and signal evaluation "sensor P", with this designation as overall term for all components of the signal recording and evaluation (such as the assemblies 100, 200, 300, 400, 500 and their alternative configurations). FIG. 3 b ) : Schematic detailed overview of the light source 100 of a sensor according to the invention, shown by way of example as an RGB light source together with the "alternative 1" of the reference measurement of the light source 200 used as active feedback and regulation of the light source. FIG. 4 : Optimally selected laser wavelengths generate "bell curves" with the new measuring method, which ideally overlap at approximately 50% of the maximum amplitude. FIG. 5 : The limit case of the selection of two adjacent laser wavelengths is present according to the new measurement method when the resulting "bell curves" overlap at 1 / e 2(= 135.34 starting from the normalized value of the amplitude=1000) of the maximum amplitude. FIG. 6 : Sketch of the vector addition for illustrating the nomenclature used. FIG. 7 : Typical right-oblique "bell curves" which show normalized z-axis-related back reflection intensity profiles as a function of their wavelengths; focal distances ("focal distances" FD) FD1<FD2<.. <FD8 entsprechen to the wavelengths λ1<λ2<.. <λ8 FIG. 8 : The result of the claimed formula for determining the sensor characteristic curve based on the signals from FIG. 7, wherein FD i indicate the z position of the individual foci. FIG. 9 : The use of the "contrast function" [r(x)] locally increases the measurement resolution, but reduces the measurement range which can be evaluated in practice. FIG. 10 : The subtraction in pairs of closely adjacent bell curves with subsequent normalization shows that the slope of the resulting characteristic curves is largely independent of the wavelength spacing of the corresponding laser wavelengths, wherein, however, with decreasing wavelength spacing--due to the almost extinction of the bell curves involved--an excessively low signal amplitude remains for the subsequent signal processing. FIG. 11 : The subtraction of the adjacent bell curves in pairs, without subsequent normalization, shows the amplitude of the resulting characteristic curves f2(x)-f1(x) for λ2-λ1=45 nm and f4(x)-f3(x) for λ4-λ3=5 nm, where x=measuring distance axis. FIG. 12 : The graphical superposition of the bell curves of λ1 (around FD1) and λ2 (around FD2), as dashed lines and logarithmically as full lines (normalized to about 1000) shows that logarithmizing shifts the intersection of the bell curves at about 80% I 0 rather than about 50% I 0 for the linear measurement data, apparently advantageous. FIG. 13 : The steepest characteristic curves with the highest possible measurement resolution are achieved with the differential measurement of two linearly detected bell curves; all other evaluation methods are less steep in the linear middle region. Figure 14: a) on the left: use of a fiber-coupled spectral-resolving measuring module 610 and b) on the right: use of a 2D colour measuring point array or a CCD camera 608; the option of a module 614 for measuring the reflectivity of the object surface is also schematically illustrated, wherein this module can also be supplemented on the left in the image. FIG. 15 : CIE "color triangle"="shoe sole diagram" with exemplary details λ 1= 450 nm, λ 2= 520 nm, λ 3= 634 nm ⇒ β 1= 0 °, β 2= 126 °, β 3= 248 ° FIG. 16 : Positioning of the color vectors from the example in FIG. 15, and the resulting vector in the xy plane FIG. 17 : Schematic construction of the resulting color characteristic number, i.e. of the color measurement result F RΣ( z), as a function of the measured reflectivity R(z). The angle α results from the vector addition since the angles of the "color vectors" are predetermined by FIG. 15 and the respective wavelength. The more wavelengths, the more accurate the color information becomes. The calibration of the color measurement will simultaneously result in a conversion table for other color information formats. FIG. 18 : Schematic cross-sectional view of the telecentric circle scanner ( 50); plan view of the focal spot path on the object surface "RKS" ( 55). Apex angle "A" (61) of the round wedge-shaped prisms (51, 52); axial distance "H" (60) of the wedge-shaped prisms (51, 52). FIG. 19 : Schematic cross-sectional view of the telecentric line scanner ( 70); focal spot path on the object surface with the length "L" ( 76). Rotation angle "W" (73) of the cube prism (71).DETAILED DESCRIPTION OF EMBODIMENTSVarious embodiments will be described below with reference to the figures. Identical and identically acting components are generally identified by the same reference numerals.FIGS. 1 and 2 show, with measured signals, the difference in the back reflection profile in the case of a desirable Hi-NA objective according to the SoA technology (FIG. 1 ) and in the case of the objective claimed here with a small NA (FIG. 2 ) when laser diodes according to the present invention are used as light sources. The use of a "perfect" designed objective for implementing the SoA-CCM method together with otherwise unsuitable monochromatic light sources, which are essential for the new method, leads to very narrow back reflections, which are far apart, do not overlap and therefore could not be evaluated using the new measurement method. The better the objective, in the sense of a diffraction-limited imaging, the narrower the back reflections.The abscissa in FIGS. 1 and 2 indicates a distance of an object surface from the (chromatic) objective. Illumination light is focused at a certain distance from the chromatic objective depending on the wavelength of the light. Depending on the measurement situation, an object surface to be examined can be located in or outside the focal planes of the illumination wavelengths. Light reflected back from the object surface can reach a light power measuring device via the chromatic objective. The higher the numerical aperture of the objective used, the smaller the distance range for which light from a monochromatic light source leads to measurable back reflections. The ordinate in FIGS. 1 and 2 indicates the measurable light power of back reflections (normalized to an arbitrary unit). In the high numerical aperture objective of FIG. 1, an illumination wavelength results only in a narrow range of distances in which an object surface generates a measurable back reflection. The back reflection thus has a narrow bell shape and the back reflections of different illumination wavelengths (520 nm and 632 nm in FIG. 1 ) do not overlap. A statement about an object distance is not possible in FIG. 1 for the distance range between the two non-overlapping bell curves. In contrast, in FIG. 2, a smaller numerical aperture chromatic objective is used, whereby monochromatic illumination light results in a back reflection with a broader bell shape. In addition, the bell curves of the back reflections overlap with the illumination wavelengths used. This creates a continuous distance measurement range. In FIG. 2, this measurement range extends substantially from the distance at which the back reflection of the smallest illumination wavelength used is measurable to the distance at which the back reflection of the largest illumination wavelength used is measurable. In FIG. 1, however, a usable measurement range is interrupted in the absence of overlapping back reflection bell curves and is limited to the narrow widths of the bell curves. The ratio in FIG. 1 is just 0.0314 at a wavelength distance between λ 2( full line) and λ 1( dashed line) of 112 nm.In direct comparison, FIG. 2 shows, by way of example, a profile of the back reflections with the measurement distance (x) which was measured with the objective of the invention, wherein a comparable wavelength distance (to that of FIG. 1 ) of 114 nm is present between the back reflection with λ 3( dash-two-dot line) and λ 2( dashed line). However, the ratio is about 0.4 here, and only about 0.12 in FIG. 2 is actually practically used.For a conventional "good measuring device" according to the state-of-the-art (SoA) chromatically confocal measurement principle, it is absolutely necessary to use an objective with as high a NA value as possible (numerical aperture), which is achieved with many lenses in order to reduce all other aberrations and to linearize and increase the longitudinal chromatic aberration as much as possible, and it is in no case possible for two reasons to use laser diodes as the light source in such devices: i) the back reflections are narrow non-overlapping spikes, so that nothing can be measured therebetween (see FIG. 1 ), and ii) the use of laser diodes (coherent monochromatic light) in a conventional device leads for various reasons to interferences both in the measuring system and in the reflected signal from the object surface if it is not just a mirror. As a result, the present invention is not intended to develop a chromatic confocal measurement device.It can be seen from FIG. 2 that the back reflection profiles overlap according to the invention, are "smooth", monotonically increasing and decreasing. By overlapping the back reflection bell curves for two wavelengths used, an object distance can be calculated particularly precisely from the ratio of the measured back reflection intensities for different wavelengths. If, on the other hand, the bell curves do not overlap, see FIG. 1, then, in simplified terms, only as many discrete distance values as illumination wavelengths are used could be determined.Interference effects as set forth above would produce an irregular structure on the edges of the curves, which would also be still time-unstable-many intermediate maxima would also arise, so that a calculation of the distance using the new method would become impossible. Typically, once lasers are in play, they are used as distance meters in interferometer devices, triangulation devices, or devices based on the time-of-flight (ToF) measurement principle. Such methods and apparatus are not recognized herein as they do not compete with the present invention.Overview of the SensorFIG. 3 a) with the detailed diagram from FIG. 3 b) shows a diagram of an entire sensor according to an exemplary embodiment of the invention, consisting of a light source 100, a distance measurement objective 800, a color measurement device 600, an "X" or "Y"-shaped optical fiber coupler 30, a spectral-resolving back reflection measurement device 500, a spectral-resolving measurement device for detecting the emission of the light source 200 [shown in FIG. 3 b) ] or 300 or 400 for the purpose of returning and regulating the output emission of the light source, a beam splitter 15, and the measurement arrangement represented by the object surface 10 and its boundary positions 11 and 12 and indicated by the illustrated beam paths 13 and possibly 16.Laser diodes 101 a, b, care preferably used as light sources in the novel measuring method, although they have many stability problems, as explained below.Laser diodes are very thermally unstable, are very sensitive to operating current variations and are subject to some long term changes in the technical specification. Therefore, according to the invention, the wavelength and the power of each laser diode used are selected as precise as possible and above all free from a possible superposition of the emission characteristic with back reflections from the measurement system or from the measurement range. The laser diodes usually contain one photodiode exactly for this purpose, e.g. the control of the output power, but these photodiodes are not suitable for use in the present invention for two reasons: a) Usually the quality of these photodiodes is not sufficient for the described purpose, since for cost reasons they have been produced in the same manufacturing process as the laser diode, so that for physical reasons they offer only a compromise solution, b) back reflections from the object under test usually return and correspondingly influence the operating point of the laser diode - which is impermissible in the present invention.This problem is taken into account in the new measuring method by the fact that three different measuring possibilities of the light source emission are proposed 200 (FIG. 3 b), or 300 (FIG. 3 a), or 400 (FIG. 3 a) as alternative solutions.In detail, here, the emissions from three laser diodes 101 a, b, care collimated via the optical components 102 a, b, c, are dichroically added via the beam splitters 103, 104, 105 and focused via 106 into the "port 1" (32) fiber plug 107. Via "port 2" ( 31), the light emission of the light source 100 reaches the fiber connector 35 and 803, so that the light 804 ain the objective 800 is collimated 804 bvia the achromatic lens 802 and focused onto the object surface 10 via the achromatic lens combination 801 (consisting of 801 aand 801 b), wherein the focused radiation 13 is deflected by preferably 90° with the beam splitter 15. The optical axis 805 of the objective 800 is preferably perpendicular to the optical axis 15 of the focused measurement radiation 13.The light scattered back from the surface 10 to be measured or partially reflected reaches the fiber connector 35 backwards via the beam splitter 15 and the objective 800, so that via the fiber "port 3" (33), the light reaches the spectral-resolving measuring unit 500 via the fiber connector 37 / 501. Here, the light 503 ais collimated (503 b) via the optical component 502 and is resolved into monochromatic partial beams 508 a, b, caccording to their wavelengths with the aid of an optical dispersion component 504 (here, by way of example, a holographic diffraction grating) and is converted into a measurable electrical current via the detectors 509 a, b, c. The dispersion properties of the component 504 must be selected such that the angles of the optical axes 507 a, b, cof the partial beams 508 a, b, cwith respect to one another become sufficiently large so that the detectors 509 a, b, cmay respectively detect the correspondingly separated partial beams 508 a, b, c exactly and exclusively.The control and regulation of the light emission of the light source 100 takes place in wavelength-related fashion and is illustrated in detail in FIG. 3 b) as "alternative 1.". Here, the light of the light source 100 after the dichroic addition is focused on the one hand into the plug 107 with the optical unit 106 and on the other hand as a partial beam 203 with the optical axis 205 onto the dispersion element 204.The remainder takes place in a similar manner to in the measuring device 500, i.e. the spectrally resolved partial beams 208 a, b, care detected by the detectors 209 a, b, cand are fed back into the light source 100 in a wavelength-related manner via the controller 23. The "alternative solutions 2 and 3" of the control and regulation of the light emission of the light source 100 are shown schematically in FIG. 3 a) ( 300 and 400). 300 is substantially identical to 200 except for the reference beam 303a from the optional "port 4" (34) of the conventional "Y" fiber splitter 30, now designed as an "X" fiber splitter. In the case where 30 is designed as a multimode circuit, the output power from the "port 4" (34) is usually about 4% of the input power from the "port 1" (32). The feedback of the actual light emission values into the light source 100 is likewise effected in wavelength-related fashion via a controller 23, as shown in FIG. 3 b). In the case that "alternative 3" [400, FIG. 3 a)] is used for the control and regulation of the light source 100, the properties of the focused light 16 after the wedge-shaped beam splitter 15 must be taken into account. Thus, care must be taken that the optical axis 17 is offset relative to the optical axis 805 and slightly tilted. Furthermore, the loci of the monochromatic light sources constituting the light source 100 are distributed on the optical axis 17 between the maximum reachable areas 21 and 22, much like the loci of the monochromatic light sources distributed on the optical axis 14, present between the areas 11 and 12. For the wavelength-related detection of the radiation 16, a sufficiently large aperture 408 is outlined, whereby the entire radiation is guided to a detection unit (such as 200 or 300), not shown, whereupon a feedback into the light source for regulation takes place via a controller (similar 23).The light backscattered or partially reflected from the object surface 10 reaches the color measuring device 600 backwards via the beam splitter 15, where it is first collimated 604 by a polychromatic lens combination 601 (consisting of 601 aand 601 b) identical to 801, in order to be detected by the actual color measuring unit 606. Due to the wedge-shaped beam splitter 15, the optical axis 605 of the color measuring device 600 is slightly offset and tilted relative to the optical axis 14.Description in the Wavelength Selection and Calculation Field of Sensor CharacteristicsTo computationally determine the distance from the two or more independent signal sources of the sensor, a monotone function must be calculated from the available signal sources. This greatly facilitates calibration of the system.Alternatively, since all signal sources simultaneously supply measurable signals, i.e., signals that are clearly evident from the noise, the detected signal pairings can be assigned to the currently set measurement distance labelarily, as a result of which the required calibration also takes place simultaneously. This method requires no further details.If two "bell curves" do not have an overlap, it is practically impossible to determine a continuous sensor characteristic curve from the measurement data. This is because standard chromatic-confocal ranging using high NA chromatic objectives cannot use laser diodes as the light source (see FIG. 1 ). In the event that there is a partial overlap of the bell curves, the calculation of the sensor characteristic curve takes place according to a very known formula of the type known also as a "contrast function" and which has already been described in DE 10 2008 029 459 B4, wherein here the signals A and B have to be determined one after the other and stored temporarily. This type of signal processing also remains important in the present application because it is very robust and normalizes the information-carrying (A-B) operation with the sum of the signals, so that, for example, influences of changes in the reflection properties of the object can be normalized away. Such a contrast function formula offers an evaluable characteristic curve only between the peak values of the bell curves, wherein the nonlinearity of the characteristic curve and thus the measurement uncertainties increase in the region of the maximum of the bell curves. For this reason, such a sensor characteristic curve, which is based only on this principle and is to be formed from a plurality of (more than 2) bell curves, could not offer an uninterrupted distance measurement of the same resolution between the foci of the edge wavelengths in the distance measurement range. This type of evaluation is generally known and is therefore only claimed here in connection with and as a supplement to the calculation of the overall characteristic curve of the sensor according to the vector addition method. In addition, it is easily understood that the use of two closely adjacent wavelengths cannot lead to a steeper sensor characteristic curve, because by subtracting two almost identical bell curves, the resulting signal is very small and the steepness of the characteristic curve is not influenced thereby (see FIGS. 9-10 ).The comparison with the use of monochromatic light sources (laser diodes) together with optical devices according to the SoA of the CCM measurement technique (see FIG. 1 ) clearly shows that in such a case no practically usable sensor characteristic curve can be determined. In contrast, FIG. 2 shows that the new measuring method ensures that a sufficient overlap of adjacent bell curves can be achieved. The bell curves are wavelength-dependent "right-sided bell curves", i.e. the half of the bell curve lying to the right of the maximum is wider than the left-hand side (cf. FIG. 5, WR1>WL1 or WR2>WL2). In order to ensure an overlap in the sense of the new measuring method, according to the invention the laser diodes of two adjacent wavelengths must be selected such that the corresponding back reflection bell curves intersect each other at an intensity value that is greater than 1 / e 2= 0,1353353 from the intensity maximum (see FIG. 5 ). In this figure, this limit case of the bell curve section is shown at 1 / e 2 wherein the two curves f1(x) and f2(x) shown represent measurement data where the wavelength difference is 70 nm. In direct comparison with Figure 4, the difference of the two curves f2(x)-f1(x) is more nonlinear.Only two bell curves offer a limited possibility of ranging, practically between the two wavelength loci ("FD 1" and "FD 2" in FIGS. 4 and 5 ). It can be seen from FIGS. 9-10 that an excessively strong overlap of two adjacent bell curves is rather unfavourable since the resulting characteristic curve, for example by calculating a "contrast function", provides a very low signal amplitude since the overlapping bell curves "destroy" each other. Therefore, the optimal distance of two adjacent wavelengths is preferably defined such that the corresponding back reflection bell curves intersect at 50% of the maximum intensity of the normalized bell curve (see FIG. 4 ). In this figure, the two curves f1(x) and f2(x) shown represent measurement data, the wavelength difference being 45 nm. Such bell curves are usually described by their width at 50% of the maximum amplitude ("FWHM 1" and "FWHM 2" in FIGS. 4 and 5 ).It should be noted that the longitudinal chromatic aberration of the objective is non-linear and thus the wavelength differences from FIGS. 4 and 5 are not the same for each usable wavelength. Thus, for example, the objective tested has a usable longitudinal chromatic aberration between 350 nm and 980 nm, from which only approximately 30% is used here in order to keep the number of laser diodes and thus the outlay low. According to the invention, the desired distance measurement range of the sensor can be taken from the chromatic characteristic curve of the objective, and the smallest and the largest required wavelength can be taken at the ends of the distance measurement range. The wavelength range lying in between must be covered with individual laser diode wavelengths in such a way that the back reflection bell curves of adjacent wavelengths intersect in each case between 1 / e 2 and 50% of the normalized maximum intensity.FIG. 9 : Measured bell curves, such as f1(x) and f2(X), which intersect in the amplitude range between n(x)=13.53% (I 0) and m(x)=50% (I 0) of the normalized peak amplitude I 0( about 1000 a.u., "arbitrary units"), are considered bell curves with the optimum wavelength, according to the selection method proposed here for adjacent wavelengths of the laser diodes. In this case, a slight nonlinearity of the bell curve difference s(x)=f2(x)-f1(x) between the two focal lengths FD 1 and FD 2 can be determined.Here, the wavelength difference is 70 nm, but this value depends on the wavelength because the polychromatic objective characteristic does not linearly depend on the wavelength. This figure also shows the comparison of the function s(X) with the "contrast function" r(x) between the two bell curves measured. It can be seen from this that the use of the "contrast function" locally increases the measurement resolution, but reduces the practically evaluable measurement range between the maxima of the two bell curves. In other words, the contrast function provides the steepest characteristic curve and thus the highest resolution in the measurement range.FIG. 10 : This figure graphically shows that the steepness of the "difference function" of two adjacent bell curves is largely independent of the difference of the corresponding adjacent wavelengths and that the smaller the wavelength difference, the smaller the amplitude of the difference function and thus the possibility of an evaluation. The wavelength difference for f4(x)-f3(x), f6(x)-f5(x) and f8(x)-f7(x) is 5 nm, 1 nm and 30 nm, respectively. In order to normalize the negative peaks of the difference curves to the same value at the level of approximately -1000 a.u., the factor 6, 43 or 4.7 had to be multiplied by the difference. The function o(x)=0 was used here only for orientation as a zero line in the diagram. The function m(x)=500 was also used for orientation, as was the case in other diagrams.FIG. 11 : Due to the small distance between the foci FD 3 and FD 4, the two corresponding bell curves are almost identical and their subtraction generates a very small signal (in the diagram f 4(x)-f 3(x)), wherein between the wavelengths λ 3 and λ 4, 5 nm are located; the bell curves around FD 1 and FD 2, which have an optimal distance from one another, wherein between the wavelengths λ 1 and λ 2, 45 nm are used as a comparison. This graph is almost identical in printpicial form to Figure 10, in which case the scaling factor of the bell curve difference was not used to clarify the amplitude difference of f2(x)-f1(x) and f4(x)-f3(x). Here, as in other diagrams, FDi are also the corresponding focal lengths of the objective for the wavelengths λ1 to λ4. The functions m(x)=500 and n(x)=135.3 have been used for orientation with reference to the description.In the present application, regardless of whether the light sources are operated in pulsed or cw mode, the bell curves are simultaneously available, which is of course advantageous since as a result the maximum reaction speed of the sensor is dependent only on the reaction speed of the photodiodes and their amplifiers.Another possibility for evaluating the sensor characteristic curve is the logarithmizing of the bell curves. In some situations this may be helpful because the intersection of the logarithmized bell curves migrates upwards [see FIG. 12 ] and thus limit cases can also be evaluated, but the noise is also greatly amplified by the logarithmizing.FIG. 12 : In this figure, the bell curves at λ1 (dot line) and λ2 (dashed line) are shown as measured curves and their normalized logarithmic conversions as full lines (normalized to approximately 1000). The logarithmized bell curves intersect at about 80% I 0 instead of about 50% I 0 for the linear measurement data, so that an improvement in the sensor characteristic curve is apparently possible. The wavelength difference here is 45 nm. The functions m(x)=500 and n(x)=135.3 have been used for orientation with reference to the description.Logarithmizing does not offer a higher measurement resolution [see FIG. 13 ]. The contrast function is applied only in addition to the overall characteristic curve [FIG. 8 ] in order to achieve a resolution that is improved locally between two adjacent wavelengths. Accordingly, the overall characteristic according to the "vector addition method" is used for object finding, and the local "contrast function" represents a kind of magnifying glass for a smaller area within the overall characteristic.FIG. 13 : In this figure, different calculation formulae (in each case indicated in the diagram) of two adjacent bell curves are compared in order to graphically show that the "contrast function" p(x) delivers the highest resolution of the characteristic curve (steepest characteristic curve). The wavelength difference here, just as in FIGS. 11 and 12, is 45 nm. The function o(x)=0 was used here only for orientation as a zero line in the diagram.For the state-of-the-art (SoA) chromatographic-confocal-measurement (CCM), the use of an optical fiber with a mode diameter as small as possible is obligatory, but limited to approximately 50 μm of GRIN (degree index) fiber, because too little power can be coupled into the fiber by the conventional non-coherent polychromatic light source.Laser diodes are used in the present invention and thus sufficient light power could be coupled into SM (single mode) fiber itself. According to the invention, however, large STIN (step-index) fiber diameters are used (≥50 μm) in order to ensure that as many transverse vibration modes as possible can propagate in the fiber, because otherwise the flanks of the back-reflection bell curves would be strongly modulated through and the calculation of a monotone sensor characteristic curve would be made more difficult. Since the propagation of the transverse modes of oscillation is inversely proportional to the wavelength, the maximum usable wavelength is also limited thereby. For increased operational safety of the present invention, what is known as a mode scrambler is also used at various locations of the "fiber coupler" 30, which costs a little power, but makes the number of transverse vibration modes clearly increase. The use of single-mode optical fibers in the present invention is not possible.Method for Calculating Sensor CharacteristicA method of calculating a sensor characteristic SK will be described with reference to FIGS. 6, 7, and 8. FIG. 6 shows a sketch of vector addition: Starting from two vectors A and B having the angles α 3 and α B with the X axis, the vectors can be described as having vertices with their coordinates: P A( X A, Y A) and P B( X B, Y B). The sum of the vectors RΣ=A+B can be calculated both graphically [as in FIG. 6 ] or analytically, in which case the peak of the vector sum can be described by its coordinates, similarly to for the individual vectors PΣ(X AB, Y AB). The angle of the vector sum WΣcan be calculated as known. The vector addition is used in connection with the calculation of a sensor characteristic curve.FIG. 7 shows the measured typical right-sided distance-related back reflection intensity profiles (bell curves) as a function of their wavelengths or focal lengths. The intensity profiles are normalized to approximately I O ≈1000. For each wavelength λ i of a monochromatic light source of the sensor light source 100, such a "bell curve" arises, wherein the smallest focal point of each wavelength arises on the optical axis 14 at the focal length FDi, such that the focal lengths FD 1<FD 2<... <FD 8 (focal distances) correspond to the wavelengths 405 nm=λ 1<λ 2<... <λ 8=750 nm.In most diagrams, as in FIG. 7, the levels of m(x)=50%·I O= 500 and n(x)=1 / e 2·I O ≈13.3%·I O= 135.3 are also displayed, respectively. These are used for the evaluation of the overlap of two adjacent bell curves.The overall sensor characteristic curve WP(x) shown in FIG. 8, which has a non-linear but monotone profile, was calculated from the bell curves [FIG. 7 ]: wherein WΣ(x) is the numerical value of the angle of the vector addition. The vectors for this addition each have as magnitude the maximum value of the corresponding bell curve and the angle is assigned depending on the wavelength. The larger the number i of wavelengths, the smoother the sensor characteristic WP(x). The function k(x) corresponds here to the asymptotic value of the function WP(x) outside the measurement range.Method for Detecting ColorDue to the wavelength-dependent focusing, the region around the instantaneous measurement point on the object surface cannot be easily detected with a further instrument, such as a camera for visualization or a color measurement device of the conventional type, because the beam path present prevents a use of the mentioned instruments according to definition.However, it is useful to solve this problem according to variants of the invention in such a way that the back reflection from the surface 10 of the object to be measured passes via a partially through beam splitter 15 into the measurement module 600 ("sensor F"), where it first passes through a chromatic unit 601 which is identical to the chromatic unit 801. As a result, the beam path 604, similar to 804 b, is shaped such that the object surface 10 can be imaged correctly with a camera. The measurement module 600 can be designed according to the invention in various embodiments, which are partially shown in schematic diagrams in FIGS. 14 a), b). It is particularly advantageous to use a fiber-coupled spectral-resolving measuring module 610 (virtually identical to the measuring module 500) for ascertaining the object surface color. For this purpose, the radiation 604 is focused (611) via the matching optics 607, in this case a converging achromate, into the optical fiber 609 and guided over it for analysis in the spectral-resolving measurement module 610. 606 [FIGS. 14 a) and b)] here generically identify the component which the radiation 604 assumes for further processing downstream of the objective 601. The module 610 [FIG. 14 a)] with the necessary beam forming ( 607, 611, 609) is replaced in FIG. 14 b) by a 2D matrix light intensity detecting module 608. This may be a color camera or a flat color sensor in which each pixel is a color sensor (usually for RGB colors). The matching optics 607 in this case matches the diameter of the radiation 604 to the active diameter of the module 608.In general, a beam splitter can be designed in any desired manner and optionally have antireflection coatings and / or surfaces arranged obliquely to the beam path in order to minimize back reflections and interference, with at the same time no optical offset or only a small optical offset.The beam splitter 15 can be designed in particular as a wedge-shaped beam splitter plate in order to avoid interference effects. However, this results in a beam offset and a beam tilt about the apex angle of the wedge.In a variation of FIG. 3 a), in principle, the beam splitter 15 can be mounted between the chromatic unit 801 and the lens 802 in order to save the objective / chromatic unit 601. However, in the case of a (wedge-shaped) beam splitter plate, the construction of the chromatic objective 800 becomes more complicated and additional aberrations arise. A plane parallel plate could be introduced, which in turn causes interferences. In principle, the use of a beam splitter cube is possible since it operates coaxially and does not cause any beam offset, but the flat surfaces of the beam splitter cube perpendicular to the beam axis can cause undesired back reflections. To avoid this, the beam splitter may be provided with an anti-reflection coating and / or slightly tilted (< 8°) to be mounted between the chromatic unit 801 and the lens 802 and to achieve a more compact design (not shown).The measurement of the object color is more complex and therefore there are a number of certified measurement methods which evaluate different color-dependent characteristic numbers, for which there are conversion formulas between one another. The measuring method proposed here is not yet known and certified, since it proposes new ways and is simpler to use. For this purpose, the reflectivity of the object surface must also be determined according to the invention using the module 614 alone or in combination with the modules 610 or 608. For most applications, it is expedient that a light L NIR with the wavelength outside the wavelength range λ 1 to λ n claimed by the distance sensor is used for measuring the reflectivity. The index "NIR" was used here in the sense of (near-infra-red), since an NIR wavelength, such as e.g. 750 nm, optimally matches this. However, other wavelengths can also be used for the reflectivity measurement. The light L NIR( without imaging) may originate from a light source (in particular a laser diode or SLED or LED) which is seated coaxially in the module 614. The beam path 613 is formed by a beam-shaping optical unit (without imaging), which is also accommodated in the module 614. The beam-forming optics also includes a beam splitter (not shown) which supplies the back reflection having the wavelength λ NIR to a detector which carries out the reflectivity measurement. The reflectivity measurement can be carried out completely separately from the color measurement in the schematically illustrated module 614, wherein in this case the beam splitter 612 is advantageously designed as a short-pass filter having the jump wavelength λ KPF, such that λ n< λ KPF< λ NIR is designed, as a result of which the radiation 613 only still contains wavelengths λ > λ KPF and thus transmits λ NIR.Reflectivity measurement must necessarily be made through the polychromatic objective 601 or 801 to be coaxial with the remaining measurements, but it has its own matching optics 607 allowing it to shape the light L NIR with the wavelength λ NIR > λ n, where λ n is the largest wavelength used in the system, so that it impinges upon the object surface in a collimated, focused or defocusing manner. In addition, it is advantageous that the adaptation optics 607 of the reflectivity measurement (without imaging, contained in the module 614) is designed to be axially movable and lockable, so that the position of the focal point formed on the optical axis 14 can be adjusted as desired relative to the object surface 10.If for the detection of the back reflection with the wavelength λ NIR, according to FIG. 14 a) takes place with a spectral resolution measurement module 610 (similar to 500), it must be ensured that the wavelength λ NIR is measured unambiguously and that the detection takes place without overlapping with other spectral components of the other lights, wherein, trivially, the beam splitter 612 must pass all the wavelengths used.In order to be able to use the reflectivity measurement simultaneously with the other measurement methods, they must be separated in such a way that they do not influence one another. For this purpose, the clock frequencies used for the reflectivity measurement and the distance measurement are so different that they also do not correspond to the harmonics of the other measurement in each case. However, there are methods of evaluating signals with different frequencies that coexist in the same system, which benefit from synchronization of the signals. In this case, the frequencies must be selected such that the beat frequency from the convolution of both frequencies differs greatly from the measured topography measurement frequency. A simpler situation arises if the distance measurement is carried out in the cw mode (continuous wave) with the clock frequency zero, then the reflectivity measurement can be operated with any desired frequency.In the general description, the module 600 (="sensor F") was first described as a color sensor or as a camera for visualizing the object surface. Of course, it is always possible to integrate a camera in this area via its own beam splitter and its own matching optics. This is considered an easily seen extension of the optical system and therefore is provided without a more detailed explanation and without drawings.The following procedure is adopted for the evaluation of the color information: 1. in the CIE "color end triangle", also called "shoe sole diagram", a cartesian XY coordinate system is superimposed in such a way that the axis origin lies at the white center point [at the CIE coordinates (about 0.33, about 0.33)] (see FIG. 15 ), wherein in principle a different color diagram can also be used; 2. the X axis of the new coordinate system connects the axis origin to the point at the edge of the shoe sole diagram, which corresponds to the smallest laser wavelength used in the sensor (e.g. λ 1= 450 nm, see FIG. 15 ). This value is also assigned the angle β 1= 0 °. The Y axis is at β=90° in the clockwise direction; 3. Corresponding to the remaining wavelengths used in the sensor: λ 2= 520 nm, λ 3= 634 nm, the corresponding points from the edge of the shoe sole diagram are connected to the axis origin; the angles result: β 2= 126 °, β 3= 248 °, which represent the directions of the "color vectors" F l, which respectively indicate the intensity of the color λ i. measured by the amount Jλi=J i=. In FIG. 16, the XY coordinate system is shown in the usual form of representation--from this it is also visible why the angle specifications in the above-mentioned manner. Item 3 and in Figure 15, respectively, have positive values. In Figure 16, the angles "correct", with positive values, are measured counterclockwise. 4. the colour vectors F l are summed and result in a resulting vector which is set in relation to the distance Z just measured: the angle βΣ = 44° is given in the drawn example in Figure 16, but otherwise it depends on the wavelengths used and on the actually measured colour intensities Jλi = J i. 5. For a correct measurement of the color, the measured reflectivity at the distance Z just measured must also be taken into account R(z) (see FIG. 17 ). The reflectivity is schematically shown in this figure in a 3D coordinate system xyr. According to the detected reflectivity, the vector determined at 4 is rotated upwards from the XY plane by the angle. The projection of the rotated vector onto the XY plane is on the vector and has the shortened value F RΣ( z) and represents the "color measurement result.". The angle α with the X axis lies in the XY plane.Alternative Use of the Novel Measuring MethodThe new tandem measurement method presented (simultaneous distance and color measurement) is fast enough to take over most known real-time measurement tasks in production lines. However, this results in topographical sensing along a line given by the manufacturing flow or by the robotic arm (or gantry) holding and moving the sensor.However, in many applications of this type, the detection of a 2D topography is preferred for two reasons: i) The small measurement spot size makes positioning of the sensor difficult to fit on the sought-after feature of the measurement object, and ii) The accuracy of robot and gantry systems is usually worse than the accuracy of the proposed new sensor, and thus any additional axis that would move the sensor across the manufacturing flow could generate additional measurement errors. From this reason, two alternative scanner methods are presented here, which enclose the new sensor unchanged and substantially extend the spectrum of potential applications.Conventionally, the known scanners include one or more components that are mechanically moved (galvanometer scanners and resonant scanners are widely used that basically perform a reciprocating oscillatory motion about a pivot point). Such devices can be operated at relatively low frequencies (several hundred Hz) since they must always overcome their own mechanical inertia at the points of inflection of the oscillatory motion, at which points the moving components (e.g. mirrors) produce additional aberrations due to their own mechanical deformation under the influence of the reversal forces.The scanner methods presented here are recently primarily due to the combination with the new measuring method and because they optimally support the properties and specifications of the new sensor. Thus, in both methods, the moving components are continuously rotated, so that no overcoming of the mechanical inertia is required and a much higher accuracy of the movement is made possible by the precise regulation of the rotational speeds.Another common property of the two scanners presented here relates to the small NA of the sensor, which does not allow large deflection angles of the measurement beam by the scanners-both are so-called "telecentric" scanners in which the beam path moved by the scanner remains parallel with itself during the entire movement. As a result, the maximum permissible angle of inclination of the object surface of the sensor alone is maintained, even for the scanner.Variant 1: Telecentric Circle ScannerIn FIG. 18, the telecentric circle scanner 50 is shown as a sketch. It consists of two round wedge-shaped prisms 51 and 52, which have the same apex angle "A" (61), are coupled to one another in such a rigid manner via a cylindrical holder 53 that the oblique surfaces of the prisms 51, 52 are exactly parallel to one another. The entire prism package 51-53 is rotatably mounted about the optical axis 57 of the sensor and can be rotated with any desired type of drive about the optical axis 57 of the sensor in a precisely controlled manner. The entire prism package is mounted between the distance sensor, indicated here as 58, and the surface 56 of the object to be measured.When the light of the distance sensor 58 focused on the measurement object surface 56 passes the first prism 51, it is redirected according to the apex angle "A" (61). In this case, the beam quality is drastically impaired and the optical axis is tilted. Due to the exactly parallel aligned apex surface of the second prism 52, which is identical to 51 all introduced aberrations and the tilting of the optical axis are completely compensated. The focal point of the sensor 58 is offset by the prism package at a distance "RKS" (55) from the sensor's optical axis 57. As a result of the rotational movement 59 of the prism package 51-53, a circular path 54 is thus formed on the surface 56 of the object to be measured. Changes in the distance "H" (60) between the two prisms are used to set the desired radius of the circular path "RKS" (55). If the two apex surfaces are exactly one above the other, RKS=0. Further, the maximum value of the circular path radius "RKS" (55) can be influenced by the apex angle "A" (61) and by the appropriate selection of the refractive index n TKS of the prisms. During the rotational movement 59, the optical axis of the light impinging on the object remains parallel to the optical axis 57 of the sensor.In order to further improve the topography measurement along the circular path 54, it is necessary according to the invention to tilt the axis of rotation of the prism assembly 51- 52- 53 with respect to the optical axis of the sensor at a small angle <8° in order to avoid direct reflections from the flat surfaces of the wedge-shaped prisms 51, 52.Variant 2: Telecentric Line ScannerIn FIG. 19, the telecentric line scanner 70 is shown as a sketch. It consists of a cube-shaped prism 71 which is mounted rotatably about the axis 72 (perpendicular to the plane of the drawing and to the optical axis of the sensor 5. The prism can be rotated about its axis 72 in a precisely controlled manner with any desired type of drive. The rotatable prism is mounted between the distance sensor, indicated here as 58, and the object surface 77.When the light of the distance sensor 58 focused on the object surface passes the prism 71, it is deflected in accordance with the rotation angle "W" 73. Since the prism exit surface is parallel with the entrance surface, beam quality is not degraded and after light exit, optical axis 74 remains parallel with sensor optical axis 57. The focal point of the sensor 58 experiences an offset from the sensor's optical axis 57 by the prism turning. The rotational movement of the prism thus produces a linear path 75 on the object surface 77. changes in the side length of the prism lead to corresponding changes in the scan length "L" 75. Simulations as a result can be used according to the invention to anti-reflection coat the optical surfaces of the prism 71 in order to be able to utilize the largest possible angle of rotation of the prism if the refractive index n is TLS >1.65. In the same context, for a refractive index n TLS< 1.65 the antireflection coating is dispensed with better.Due to the shape of the cube prism 71, four line measurements of the object topography per revolution of the cube prism 71 are carried out. The corners of the cube prism 71 should be blackened in order to be able to sharply delimit the ends of the scanline "L" 75 before the measurement signal intensity decreases too much. During the rotational movement of the cube prism, the focal point of the sensor 58 moves on a "light" hyperbolic path in the plane formed by the optical axis 57 and the imaginary scanline 75, with the maximum of the hyperbolic line being at the intersection with the optical axis 57. The term "light" hyperbolic trajectory has been used because the deviation of the actual trajectory from a straight line is small and much smaller than the height measurement range of the sensor 58, so this deviation can be compensated for with a straight object surface. In order to further improve the topography measurement along the line "L" (75), it is necessary according to the invention to tilt the axis of rotation 72 of the cube prism 71 with respect to the optical axis of the sensor at a small angle <8° in order to avoid direct reflections from the cube surfaces.List of reference characters10 Surface 11 of the object to be measured: focal plane of the longest wavelength used (red) 12 focal plane of the shortest wavelength used (blue) 13 "chromatic" beam path after beam splitter (15) 14 optical axis of the measurement on the object 15 wedge-shaped, AR-coated, optical axis of the measurement on the object 15, (e.g. R:T=90:10) Beam splitter 16 "chromatic" beam path for alternative 3_Ref measurement (400) 17 Optical axis of the 18 angle between the objective 1_OA (805) and 14 (90°) 19 angle between the objective 1_OA (805) and objective 2_OA (605) (90.5°) 21 Focal plane of longest wavelength (red) Alternative 3_Ref measurement (400) (*) 22 Focal plane of shortest wavelength (blue) Alternative 3_Ref measurement (400) (*) (*) If no optical components (lenses, filters, (*), Mounted in the path are 23 wavelength related regulator and controller of light source emission 30 "Y" fiber coupler or MM "Y" circulator 31 "Port 2" / output fiber "Y" coupler to "chromatic" objective (800) 32 "Port 1" / input fiber "Y" coupler from laser diode module (100) 33 "Port 3" / output fiber "Y" coupler to measurement module (500) 34 "Port 4" / optional Y coupler output to alternative 2_Ref. measurement (300) 35 FC / APC fiber plug to chromatic objective #1 (800) 36 FC / PC fiber plug to RGB laser diode module (100) 37 FC / PC fiber plug to measurement module (500) 38 FC / PC fiber plug to Ref.2 measurement module (300) 50 telecentric circle scanner 51 round wedge-shaped prism with apex angle "A" (51) and refractive index n TKS52 round wedge-shaped prism with apex angle "A" (51) and refractive index n TKS53 mounted rotatably about optical axis 57, Rigid coupling of the prisms 51 and 52 54 Plan view of the circular path (radius "RKS" = 55) of the focal point of the chromatic confocal distance sensor (58) 55 Radius "RKS" of the scanner path on the object surface 56 Measurement object surface 57 Optical axis of the chromatic confocal distance sensor (58) 58 Chromatic confocal distance sensor 59 indicated rotation of the two rigid coupled prisms 51 and 52 60 Distance "H" of the two rigid coupled prisms 51, 52 61 Apex angle "A" of the two rigid coupled prisms 51, 52 70 Telecentric line scanner 71 Cube-shaped prism made of glass having the refractive index n TLS72 axis of rotation of the prism 71, Depicted perpendicularly on paper 73 Angle of rotation of the prism 71 about the axis 72 74 Optical axis at the measurement point parallel to 57 75 path of the focus on the object surface 77 during 71 rotates 76 Length "L" of the focus path on the object surface 77 77 Object surface 100 RGB laser module / light source 101 a, b, c RGB laser diodes 102 a, b, c Collimating lenses for RGB laser diodes 103 Dichroic mirror 104 Dichroic mirror 105 Dichroic mirror 106 Achromat for beam focusing into the fiber (32) 107 Fiber jack for receiving (36) 110 Output light beam of the RGB module (100) 200 Alternative 1, Reference measurement for LD feedback [FIG. 3.b] 201 Fibre plug socket for FC / PC fibre plug 202 Collimating lens, Achromat 203 a, b Beam path in front of the grating (204) 204 Dispersive element, e.g. holographic diffraction grating 205 Optical axis of the beam path (203) 206 Normals on the diffraction grating 207 a, b, c Optical axes of the diffraction beams 208 a, b, c Diffraction beams according to the wavelengths 209 a, b, c Photodetectors used, preferably PIN photodiodes 210 a, b, c Transimpedance amplifier 211 a, b, c Outputs of the transimpedance amplifiers (210) 300 Alternative 2, Reference measurement for LD feedback 301 Fibre plug socket for FC / PC fibre plug 302 Collimating lens, Achromat 303 a, b Beam path in front of the grating (304) 304 Dispersive element, e.g. holographic diffraction grating 305 Optical axis of the beam path (303) 306 Normals on the diffraction grating 307 a, b, c Optical axes of the diffraction beams 308 a, b, c Diffraction beams according to the wavelengths 309 a, b, c Photodetectors used, preferably PIN photodiodes 400 Alternative 3, reference measurement for LD feedback 408 Aperture for light detection 500 Measurement module distance (light power measuring device) 501 Fiber plug socket for FC / PC fiber plug 502 Collimating lens, Achromat 503 a, b Beam path in front of the grating (504) 504 Dispersive element, e.g. holographic diffraction grating 505 optical axis of the beam path ( 503) 506 normals on the diffraction grating 507 a, b, c optical axes of the diffraction beams 508 a, b, c diffraction beams according to the wavelengths 509 a, b, c photodetectors used, Preferably, PIN photodiodes 600 chromatic objective "color" and color measurement 601 chromatic unit (hyper-chromate) #2 601a convergent lens #2 601b divergent lens #2 604 optical path after chromatic unit #2 (601) 605 optical axis of chromatic unit #2 (601) 606 color measurement device or camera 607 matching optics 608 2D array sensor (CCD camera or consisting of color measurement points) 609 multi-mode step index optical fiber as connection 606 with 610 610 spectral resolution measurement module (practically identical to 500) 611 optical path 604 focused on the entrance window of fiber 609 612 beam splitters: >90% transparent to 604 and >90% reflective to 613 613 613 optical path of reflectivity measurement for λ NIR > λ n= largest wavelength 614 light source and beamforming for reflectivity measurement with λ NIR800 chromatic objective "distance" 801 chromatic unit (hyper-chromate) #1 801a convergent lens #1 801b divergent lens #1 802 collimator lens, achromat 803 FC / APC fiber jack 804a, b optical path within objective #1 (800) 805 optical axis of chromatic objective #1

Claims

Distance measuring method according to the principle of chromatic confocal distance measurement, characterized in that a polychromatic light source (100) comprises a plurality of single-mode or multimode, pulsed or continuous-mode laser diodes (101a, b, c), in that the light (110) obtained in this way is focused into a multimode "Y" or "X"-shaped splice fiber coupler (30) having a fiber core diameter of at least 50 μm, preferably designed as a "multimode circulator", in that an output fiber of the fiber coupler (30) is introduced into a chromatic objective (800) via an FC / APC fiber plug (35, 803), in that the wavelengths of the light (110) of the light source (100) are focused at distinct focal points on the optical axis (14) at different distances according to a longitudinal chromatic aberration characteristic of the objective (800) such that a resulting back reflection from an optical at least partially reflecting measuring object surface (10), which lies at 90°±arctan(NA), approximately perpendicular to the optical axis between the foci of the shortest and longest used laser diode wavelengths, reaches via the chromatic objective (800) back into the fiber coupler (30) and is supplied via a measurement output fiber (33) of the fiber coupler (30) to a spectral-resolving, light power measuring device (500), which measures each of the used monochromatic wavelengths separately.Method for selecting the appropriate laser diodes (101a, b, c) or their wavelengths for implementing the chromatic confocal distance measurement method according to claim 1, wherein a sensor contains the polychromatic light source (100), the fiber coupler (30), the fiber plug (35, 803), the chromatic objective (800) and at least one photodiode (509a, b, c), wherein the sensor detects, for each laser diode wavelength, the confocal back reflection having the form of a right-sided intensity distribution over the optical axis of the sensor and having the maximum value in the coaxial focus of the sensor for the selected wavelength, characterized in that the smallest and the largest wavelengths are selected such that a desired distance measurement range lies between the foci of the smallest and the largest wavelengths according to the chromatic characteristic of the objective (800), and that for continuous measurement of the distance within the distance measurement range a minimum number of additional laser diodes (101a,b,c) whose emission wavelengths lie between the smallest and the largest selected wavelength is selected such that resulting back reflection bell curves of two adjacent wavelengths intersect each other at an intensity value which is greater than 1 / e 2= 0,13533 of an intensity maximum of one of these wavelengths.Method according to claim 1 or 2, characterized in that the method is carried out as part of an interferometric measuring method.Method for determining a monotone sensor characteristic curve from measurement signals at different distances from a surface (10) to be measured, wherein the sensor characteristic curve is used for calibration for the distance measurement method according to Claim 1 or the method according to one of Claims 2 and 3, characterized in that each measurement signal having wavelength λ i is assigned a vector R%0020̄ l in such a way that the vector magnitude corresponds to the measurement signal variable Iλi= I i and in that the vector angle αλi= α i to a horizontal axis in a Cartesian coordinate system corresponds to a value which is assigned in accordance with the wavelength in such a way that the smallest wavelength λ 1 in particular α 1= 0 °, used corresponds to, the angles α 2 to α n-1 lying between the largest wavelength λ n in particular α n= 90 ° and the remaining wavelengths are assigned to the largest wavelength according to a numerical ratio of the wavelengths, wherein the vectors R l%0020̄ are summed up in vector terms and the angle WΣ(z) of the resulting vector R Σ%0020̄ is used as or for the z-dependent sensor characteristic curve in order to calculate a monotone sensor characteristic curve over the entire working measurement range between the foci of the smallest and the largest wavelength used, wherein the angle of the resulting vector W Σ(z) = arctan y Σ x Σ and wherein z is the axial measurement coordinate, y is σ = ∑ i = 1 n I i sin α i, x ∑ = ∑ i = 1 n I i cos α i .Method according to claim 4, characterised in that the angle WΣ(z) for linearisation is standardised with the magnitude of the resulting vector B Σ ( z ) = x Σ 2 + y Σ 2 and is denoted by S Σ ( z ) = W Σ ( z ) B Σ ( z ) wherein S Σ(z) is used as the z-dependent sensor characteristic curve.Method according to one of claims 1 to 5, characterized in that the objective (800) is designed with a small numerical aperture NA < 0.2 and a ratio of the longitudinal chromatic aberration to its focal length for the shortest wavelength used of 0.15 to 0.5.Method according to claim 6, characterized in that the objective (800) consists either of an achromatic collimating lens and a coaxially mounted polychromatic combination of two spatially separated optical components or only of such a polychromatic combination of optical components.Method according to claim 7, characterised in that the hyperchromatic combination consists of two optical, coaxial and spatially separated components, wherein the components are either two refractive, or one refractive and one diffractive optical component.Method according to one of Claims 1 to 8, characterized in that a broadband beam splitter (15) is used for simultaneously detecting an object colour, in the beam path between the objective (800) and the measurement object surface (10) or between the lens (802) and the chromatic unit (801), wherein the broadband beam splitter (15) deflects a portion of the light reflected by the measurement object surface (10) in terms of power in the direction of a colour measurement apparatus (606).Method according to claim 9, characterised in that the beam splitter (15) is designed as a wedge-shaped beam splitter for avoiding reflections and / or etalon effects, in particular with a wedge angle of 0.5°.Method according to one of Claims 1 to 7, 9 or 10, characterized in that the light reflected back from the surface (10) to be measured is fed without passing through a limiting aperture to a spectral resolution measuring device (606), which supplies an intensity signal to a superordinate signal evaluation unit for each wavelength used.Method according to one of Claims 2 to 5 and 9 to 11, characterized in that, for the evaluation of acquired colour information, each measurement signal having the wavelength λ i is assigned a vector F i in such a way that the vector magnitude corresponds to the measurement signal variable Jλi= J i and in that the vector angle βλi= β i to a horizontal axis in a Cartesian coordinate system corresponds to a value which is assigned in such a way corresponding to the wavelength, wherein the smallest wavelength λ 1 used is assigned a first vector angle β 1 and the remaining wavelengths λ 2... λ n are assigned the angles β 2 to β n in accordance with wavelength information on the edge of the color diagram, wherein the zero of the Cartesian 2D coordinate system lies in the white, i.e. achromatic, center of the color diagram, and wherein the vectors F i are summed up in vector terms to form a resulting z-dependent vector F Σ%0020̄ (z) which is then summed up for taking into account the detected object reflectivity R(z), with its origin at the origin of the XY-cartesian coordinate system being pivoted out of the XY plane with the angle ε = a r c t a n R (z) Σ i = 1 n | F%0020̄ i | and the length of the path from the origin of the cartesian coordinate system to the projection of the tip of the pivoted vector F Σ%0020̄ (z) onto the XY plane is used as the color measurement result F RΣ( z), z being the axial measurement coordinate of the object surface and α being the angle of the resultant vector with the x axis.Method according to claim 12, characterized in that the chromaticity diagram is a shoe sole chromaticity diagram and that β 1= 0 ° applies for the smallest wavelength used.Method according to Claim 12 or 13, characterized in that the z-dependent "sensor F" (600) colour measurement result F RΣ( z) is normalized for linearization with the geometric sum of the spectral vector amounts B F Σ ( z ) = Σ i = 1 n | F%0020̄ i | 2 and is denoted by S F Σ ( z ) = F R Σ ( z ) B F Σ ( z ) wherein SF Σ(z) is used for evaluating the captured colour information.Method according to one of Claims 12 to 14, characterized in that, in the case of objects having a surface which reflects the light (13) in a different diffuse manner up to specular, a further light L NIR outside the visible wavelength range is reflected into the beam path around the optical axis (14) in such a way that it impinges, preferably collimated, on the measurement object surface (10), around the measurement point.Method according to claim 15, characterised in that the additional light L NIR is also detected in the colour measurement device (606) in a wavelength-selective manner and that the measured intensity J NIR, which corresponds to the object surface reflectivity, is used for the correction and calibration of the colour measurement result F RΣ( z).A sensor adapted to perform the method of claim 2 or any of claims 3 to 16 when related to claim 2, wherein the sensor includes the polychromatic light source (100), the fiber coupler (30), the fiber plug (35, 803), the chromatic objective (800) and at least the photodiode (509a, b, c).

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