Confocal chromatic ray distance measurement system and method

Abstract

A confocal chromatic beam distance measuring system comprising a line light source (2), an aperture (3), a confocal chromatic measuring lens (6), preferably a rotationally symmetric confocal chromatic measuring lens, and a spectrometer (14), preferably a two-dimensional spectrometer, in which the illumination beam path extends from the line light source (2) to the measurement object (9) via the aperture (3) and a first area (5) of the confocal chromatic measuring lens (6) and the imaging beam path extends from the measurement object (9) to the spectrometer (14) via a second area (11) of the confocal chromatic measuring lens (6). Furthermore, a confocal chromatic beam distance measuring method is also defined.

Description

TECHNICAL FIELD

[0001] The present invention relates to a confocal chromatic light beam distance measurement system comprising a line light source, an aperture, a confocal chromatic measurement lens, and a spectrometer.

[0002] Furthermore, the present invention relates to a confocal chromatic light beam distance measurement method.

BACKGROUND ART

[0003] Systems and methods for confocal chromatic point distance measurement have been known in the industry for many years. These systems and methods are characterized by extremely high distance resolution, with a measurement point diameter in the range of several micrometers (3 μm to 30 μm). This makes it possible to achieve particularly high resolution in the lateral direction and the distance direction in the scanning process, and the resolution has a measurement spot diameter that is up to 10 times larger than that of the point triangulation method. A further advantage of confocal chromatic distance sensors is that they have less speckle and less associated influence compared to laser light sources. Furthermore, when measuring the thickness of thin layered objects, significantly higher depth resolution can be achieved, and the small sensor size in the region of the measurement object results in a low possibility of collision between the sensor and the measurement object.

[0004] Furthermore, confocal chromatic light beam distance measurement systems are already known and can be basically divided into two approaches. One is a method for projecting and measuring light beams concentrically through a confocal chromatic aberration lens, and the other is a method using the principle of confocal chromatic theta microscopy.

[0005] The former approach basically has the advantages of a compact design and ease of use due to the slightly confined spherical working space around the measurement range. It is also possible for the user to change the lens.

[0006] The latter approach offers significant improvements in depth resolution (z) and lateral resolution (x), but it has limitations, including a complex and space-consuming mechanism and the need for complex adjustments during sensor manufacturing. In one-dimensional confocal chromatic distance measurement, the colored focal array lies on the lens axis, but this principle has severe limitations when projecting and imaging a colored ray array that lies in the same plane as the lens axis. In practical terms, this is because a spread occurs between the illumination focus and the display focus, causing crosstalk to always occur within adjacent channels at close measurement positions. This is because the corresponding transmitting and receiving beams overlap very strongly, especially in the Z direction.

[0007] Therefore, in Patent Document 1, instead of projecting and observing a continuous line, a fiber array is used, employing a series of individual measurement points for projection and detection. Because these individual measurement points are very far apart, the effects of crosstalk between multiple individual channels can be ignored.

[0008] The advantage of confocal chromatic theta microscopy is that, due to its very large effective aperture, the depth of field of the illumination and observation focus can be significantly reduced without losing too much of the measurement range in the Z direction. Patent Document 2 discloses that a confocal chromatic irradiation optical system emits multispectral rays to form a ray array that has been converted into spectral data, and that this ray array is located at an angle theta (Θ) with respect to the optical axis of the lens, forming a measurement surface. The second optical system is positioned at a negative angle theta (-Θ) with respect to the measurement surface and forms an image on the region detector based on the Scheinproof principle. To evaluate the color code on the sensor representing the measured height, a color gradient filter takes over the function of the spectral aperture. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] U.S. Patent Application Publication No. 10725178(A1) [Patent Document 2] European Patent Application Publication No. 2901102 (A1) Specification [Overview of the project] [Problems that the invention aims to solve]

[0010] This invention is based on the challenge of designing and further developing a confocal chromatic ray distance measurement system and method that enables synchronous measurements along the entire ray with high depth resolution, low space requirements, and fast measurement speeds. [Means for solving the problem]

[0011] With respect to the system, the above-mentioned problems are solved by the features of claim 1. Therefore, the confocal chromatic ray distance measurement system is a confocal chromatic ray distance measurement system comprising a line light source, an aperture, a confocal chromatic measuring lens, preferably a rotationally symmetric confocal chromatic measuring lens, and a spectrometer, preferably a two-dimensional spectrometer, wherein the irradiation beam path extends from the line light source to the object to be measured via the aperture and a first region of the confocal chromatic measuring lens, and the imaging beam path extends from the object to be measured to the spectrometer via a second region of the confocal chromatic measuring lens. The term "rotational symmetry" also includes embodiments in which lenses have angular trim but are arranged or designed to be rotationally symmetric in the broadest sense.

[0012] Regarding the method, the above-mentioned problems are solved by claim 20. Accordingly, a confocal chromatic ray distance measurement method is provided, using a confocal chromatic ray distance measurement system described in any one of claims 1 to 19, wherein an irradiated light is directed from a line source to an object to be measured through an aperture and a first region of a confocal chromatic measuring lens as a colored irradiated surface, and spectrally digitized measurement light is guided from the object to a spectrometer, preferably a two-dimensional spectrometer, through a second region of the confocal chromatic measuring lens, and the distance is determined by performing spectral analysis of the measurement light.

[0013] According to the present invention, it is recognized that the fundamental problem can be solved by a confocal chromatic hyperspectral light spatial measurement system that follows the resolution enhancement principle of confocal theta microscopy. For example, a continuous beam of white light can be projected onto the object being measured, and its height profile is reflected in the color coding of the Z-direction distance to the measuring lens. Based on the spectral hyperspectral analysis of this measurement line, synchronized, locally continuous, and high distance resolution can be achieved across the entire ray. The corresponding analysis can be performed by an evaluation unit built for this purpose, such as a computer.

[0014] In a system comprising a line light source, an aperture, a confocal chromatic measuring lens, and a spectrometer, a first region of the measuring lens (e.g., half of the measuring lens) is used to illuminate the measurement point with a spectrally digitized array of rays, and another second region of the measuring lens (e.g., the other half of the measuring lens) is used to image the spectrally digitized height profile reflected by the object being measured. This means that the illumination path and the imaging path are separated from each other, and the approach of a confocal chromatic theta microscope can be realized with just one measurement lens. Furthermore, the measuring lens performs the functions of both an illumination optical system and an imaging optical system. The opening may be designed as an independent element or as part of the linear light source. Furthermore, the opening may be, for example, a slot-shaped opening.

[0015] As a specific configuration, the linear light source may be arranged on the incident side of the focal point of the confocal chromatic measurement lens. Furthermore, the incident opening of the spectrometer may be arranged on the exit side of the focal point of the confocal chromatic measurement lens. In order to divide the confocal chromatic measurement lens into two regions or two functional half-regions, the confocal chromatic measurement lens may be shielded using, for example, a directional opening, as a result of which the light is not distributed symmetrically within the confocal chromatic measurement lens, but is distributed only in the first region of the measurement lens. By using this configuration of the present invention, the measurement light passes through only one side of the measurement objective lens, and the multispectral rays coming only from that one side of the measurement objective lens spread in a fan shape so as to form a group of curves that can exist as a plane within the optical axis of the measurement objective lens. When the measurement object is present on this plane, a height profile is created, and the distance from the height profile to the measurement lens is reflected by the color focused at this distance. The height-encoded chromatic profile light beam generated on the measurement object is reflected by the second region of the confocal chromatic measurement lens to the position of the linear light source.

[0016] In a further method according to the present invention, since the irradiation beam path and the imaging beam path are different paths, the drawback occurring in the same optical path, that is, the drawback that lateral crosstalk occurs between adjacent measurement positions due to the overlap of the transmission beam and the reception beam, is avoided. In this way, signal degradation "crosstalk" can be avoided without resorting to the likewise disadvantageous solution of an irradiation point array that requires measurement intervals in the lateral direction. As a result, the measuring instrument according to the present invention enables high-speed two-dimensional continuous light beam measurement with a large depth of field. A further advantage resides in the spectral evaluation of colored height profiles. In the prior art, this profile is evaluated by a triangulation method using spectral filtering, so it is necessary to arrange a color gradient filter in front of the matrix. This filter has the same wavelength curve as the focal plane and functions as a color gradient aperture. This achieves a type of "autofocus". However, if this filter is inaccurate, the focal plane of the first confocal chromatic lens will not exactly coincide with the detection surface, resulting in accuracy errors. These problems do not occur when using a spectrometer.

[0017] The measured light beam is evaluated by a spectrometer, preferably a two-dimensional spectrometer, and this light beam is spectrally resolved on the matrix, so the colored height profile is evaluated only after spectral resolution, for example, by a CMOS area detector. Sensor-specific insensitive regions between individual pixels can be compensated, for example, by a microlens array. In other words, since the signal is passed to the matrix in analog form, it is the matrix of the spectrometer that affects the quantization noise.

[0018] Furthermore, it is recognized that the concentric lens arrangement of the measuring lens has the advantage of being much easier to manufacture. Furthermore, this type of measuring lens has the advantage that the form factor provides more free space around the lens. A further advantage is that the measuring range, and thus also the resolution of the measuring system, can be changed simply by changing the measuring lens. This is because the measuring lens generates a measuring surface from multispectral lines and integrates this measuring surface into the colored light beam. The imaging position and imaging scale for the line light source are independent of the measuring lens. Therefore, the width and height of the measuring surface projected by the measuring lens, and thus the resolution, are independent of the rest of the measuring system. Furthermore, the system according to the present invention is extremely compact because it eliminates both the cross-measuring lens arrangement and the multi-fiber arrangement required in known systems. Even if the diameter of the measuring lens can be reduced in a cross-measuring lens arrangement to achieve the same depth resolution, the measuring lens diameter must be the same as that of the system of the present invention in order to achieve equivalent tilt characteristics. Here, "slope characteristics" refers to the angle at which the surface normal of the object being measured can be positioned relative to the axis of the measurement system, meaning that the signal-to-noise ratio of the measurement light is sufficiently good. This quality standard is important when measuring curved surfaces.

[0019] It is advantageous if the confocal chromatic measurement lens, the spectrometer's entrance aperture, and, if applicable, other parts of the system (conversion optics) are aligned on a common virtual (imaginary) optical axis.

[0020] It is advantageous for a confocal chromatic measurement lens to have only one lens. This lens may be a field-correcting lens, such as a pressed double spherical lens or a double aspherical lens. Alternatively, the confocal chromatic measurement lens may have at least two optical lenses. These lenses may be arranged concentrically with respect to each other. This results in a particularly simple design for the measuring lens and a smaller installation space.

[0021] Having a single confocal chromatic measurement lens is advantageous. Using only a single measuring lens whose measurement surface lies on the optical axis has the advantage of creating a much larger and more spherical free space around the measurement point compared to a system with multiple measuring lenses. This means that the confocal chromatic ray distance measurement system can be flexibly used for automated measurements. This principle makes it possible to place the measuring lens inside a hole, significantly expanding the range of applications of this system compared to, for example, a system with multiple measuring lenses. Furthermore, a design with only a single measuring lens has the advantage that thermal effects are reflected in both the irradiated light and the measured light. Due to its symmetrical design, the thermal effects on the measurement system are more uniform than in arrangements with multiple measuring lenses, and therefore easier to correct. In the case of multiple measurement lens configurations, the irradiation source and the measurement surface may be far apart, making them susceptible to the effects of thermal changes. Another advantage of using a single measuring lens compared to using multiple measuring lenses is that the focal length tolerance becomes irrelevant. Manufacturing and adjustment tolerances of measuring lenses can directly lead to a decrease in quality when using two measuring lenses, as the illumination surface of the first lens may not be precisely positioned directly above the measurement surface captured by the second lens. Furthermore, maintaining the same spectral focal position across the entire distance range is also difficult.

[0022] Compared to a system with two separate measuring lenses that intersect each other and have limited approximation, using a single measuring lens with a very narrow measurement range makes it possible to achieve particularly high lateral resolution at high light intensity.

[0023] It is even more advantageous if the optical axis of the confocal chromatic measurement lens coincides with the system's distance axis. This approach has the advantage of requiring almost no installation space for the system and allowing the measurement surface to be placed in a location easily accessible to the user.

[0024] It is even more advantageous if the line light source emits a continuous beam of white light. In this invention, by arranging the irradiation path and the imaging path separately, a continuous line light source can be used. This is impossible with the same optical path, because, as mentioned above, the transmitting beam and the receiving beam overlap. By using continuous white light, high lateral and depth resolution can be achieved.

[0025] It is particularly advantageous if the line light source emits two or more, preferably continuous, irradiation lines. Furthermore, two or more line light sources may be arranged, and each line light source may emit at least one, preferably continuous, line of light as illumination. In this configuration, two or more parallel irradiation lines are projected and evaluated. In one embodiment, the illumination light of various irradiation lines may be generated from a common light source and emitted simultaneously from multiple apertures, emitted from separate, individually controllable light sources, or emitted from a common light source having multiple individually shieldable apertures. The aperture of the light source is positioned near the virtual optical axis, and the degree of proximity may be defined, if necessary, for example, as half the profile length from the virtual optical axis. As described in the following embodiments, a single spectrometer, preferably a two-dimensional spectrometer, such as a Dyson spectrometer, may be used. The spectrometer may have the same number of entrance apertures as the number of irradiation lines. The position and distance of the entrance aperture may correspond to the position and distance of the light source, but scaling caused by the conversion optical system must be taken into consideration.

[0026] It is advantageous for the line source to be positioned on the incident side of the focal point of the confocal chromatic measurement lens. This configuration simplifies the beam path and allows for accurate acquisition of measurements.

[0027] It is even more advantageous if the deflection element is located within the irradiation beam path and / or the imaging beam path. In the apparatus according to the present invention, since the line light source and the image formation are in the same spatial position, the deflection element can deflect the irradiated light and / or the measurement light. The deflection element may always be placed in the irradiation path or the imaging path. Specifically, the deflection element can be placed between the aperture of the irradiation beam path and the confocal chromatic measurement lens, and / or between the confocal chromatic measurement lens of the imaging beam path and the spectrometer. By placing deflection elements in both the irradiation beam path and the imaging beam path, a particularly compact design becomes possible. It is also conceivable that the deflection element functions as a directional aperture to block the illuminated light so that it strikes the confocal chromatic measurement lens only in the first region. The directional aperture may be implemented as a separate element from the deflection element. A single optical element within the beam path permanently defines the range from which light is emitted, thereby defining the region illuminated by the chromatic optical system.

[0028] It is particularly advantageous if the deflection element is designed as a mirror or beam splitter. The advantage of the mirror is that energy loss occurs within the range of 0% to 3%. The use of a beam splitter is also a possibility, but in this case, at least 75% of the energy would be lost.

[0029] A design that incorporates a conversion optical system is even more advantageous. While a relatively large line light source may be used to achieve sufficient light intensity, this also results in a considerably smaller area scan camera, which is technically and economically efficient. This imbalance can be compensated for by a transformation optical system. As a general rule, the conversion optical system adjusts the length of the aperture or irradiation slit to match the length of the spectrometer's entrance aperture. It is advantageous to position the conversion optical system between the confocal chromatic measurement lens and the spectrometer. Because this location offers the greatest return with the least effort. Another possible position for the conversion optical system is between the light source and the confocal chromatic measurement lens, in which case the illumination is incident on the lens at a reduced size. In other words, a conversion optical system is a conversion element that adapts technically available elements to a line light source and a spectrometer.

[0030] It is advantageous for the conversion optical system to have at least one optical lens, which is either concentrically positioned with the confocal chromatic measurement lens in the basic optical model, or located on a common virtual (imaginary) optical axis together with the confocal chromatic measurement lens and possibly other elements (aperture, spectrometer entrance slit). Because they are arranged concentrically, an optimized optical design is possible for all points in the region, even without an ideal parallel beam section.

[0031] The spectrometer or two-dimensional spectrometer could also be a Dyson spectrometer. To improve the measurement speed, it is essential to supply a sufficient number of photons to the detector elements. If the signal path is to pass through from start to finish, the detector needs to have high quantum efficiency. Choosing a Dyson spectrometer for analyzing reflectance light offers the additional advantage that the evaluation area detector is illuminated almost vertically, and the illumination angle is not as large as required by the triangulation method based on Scheinproof's principle. This approach maximizes the quantum efficiency of this crucial element, positively impacting the overall signal processing. Dyson spectrometers enable a large incident numerical aperture (NA), which is linked to the observed NA of the object being measured via the imaging scale. When the inclination angle of the object being measured is large, it is necessary to maximize the numerical aperture. Specifically, the spectrometer may have an entrance aperture (especially a slit-shaped one), an optical lens (especially a Dyson lens), a diffraction grating (especially a concave one), and a region detector. This design has the advantage of a simple structure and high measurement accuracy.

[0032] It is even more advantageous if the diffraction grating is a blazed diffraction grating and / or has an equally spaced parallel structure. Blazed diffraction gratings have the advantage that their efficiency improves with the order of diffraction used. Furthermore, the width of the entrance opening may be 20 μm or less, preferably 10 μm or less. This has the advantage of achieving ideal spectral resolution for the pixel resolution of the region detector.

[0033] It is particularly advantageous if the illumination beam path and the imaging beam path between the confocal chromatic measurement lens and the object to be measured extend at an angle of 30° to 160°, especially 60° to 120°, preferably 85° to 95°, and ideally 90°. This approach has the advantage of achieving the highest possible spatial resolution. By mounting the measurement surface horizontally, it is possible to achieve significantly higher depth resolution than with concentric circular irradiation where the irradiation path and imaging path are not separated. This is because the numerical aperture (NA) is very high. Depth resolution, that is, the ability to distinguish between two adjacent points or planes in the Z direction, is also significantly improved. Ideally, imaging occurs when the angle between the measurement beam path and the imaging beam path is 90°, and the smaller the angle, the more the effect of shadows on steps can be reduced.

[0034] Furthermore, it should be noted that the features of the confocal chromatic ray distance measurement system according to the present invention, as described above, also have embodiments in terms of procedures. Combining these features with those related to method claims is not only possible, but also advantageous.

[0035] There are various possibilities for advantageously designing and further developing the method of the present invention. Please refer to the following description of embodiments of the present invention, on the one hand with reference to the claims following claim 1, and on the other hand with reference to the drawings. In connection with the description of embodiments of the present invention with reference to the drawings, general embodiments and further embodiments of the method of the present invention will also be described. [Brief explanation of the drawing]

[0036] [Figure 1] This is a schematic diagram of one embodiment of the confocal chromatic ray distance measurement system according to the present invention, and the method according to the present invention can also be explained. [Figure 2] This is a three-dimensional schematic diagram of the embodiment shown in Figure 1. [Figure 3] This is a schematic diagram of a further embodiment of the confocal chromatic ray distance measurement system according to the present invention, and the method according to the present invention can also be explained. [Figure 4] This is a schematic diagram of the theoretical beam model that forms the basis of the method according to the present invention. [Figure 5] This is a schematic diagram of a further embodiment of the confocal chromatic ray distance measurement system according to the present invention, and the method according to the present invention can also be explained. [Figure 6] For three different measurement surfaces, the position m of the light ray is plotted over the measurement distance z. [Figure 7] This is an example of a profile of the object being measured, imaged by a region detector, and recorded based on the measurement surface. [Figure 8] This is an illustrative diagram of three spectral ranges, with the line m of the region detector plotted on the column n of the region detector. [Modes for carrying out the invention]

[0037] Figures 1 and 2 show a first embodiment of the confocal chromatic ray distance measurement system according to the present invention. In this confocal chromatic ray distance measurement system, white light 1 is emitted from a line light source 2 having an aperture 3, such as a slit opening. The illumination light 1 is directed by the deflection element 4 to the first region 5 of the confocal chromatic measurement lens 6. In this embodiment, the confocal chromatic measurement lens 6 has two optical lenses 7 and 8 that are arranged concentrically with respect to each other. Irradiation light 1 is directed onto the object to be measured 9 from the confocal chromatic measurement lens 6. This clearly shows that the irradiation beam path defined by the irradiation light 1 passes only through the first region 5 of the confocal chromatic measurement lens 6.

[0038] The measurement light 10, which is reflected by the object to be measured 9 and has a height profile for each wavelength, passes only through the second region 11 of the confocal chromatic measurement lens 6. The conversion optical system 12 is used to shorten the length of the measurement light 10 to the length of the incident aperture 13 of the spectrometer 14. Distance measurement is performed by hyperspectral spectroscopy analysis of this measurement line. Therefore, the imaging beam path defined by the measurement light 10 exists separately from the irradiation beam path of the method according to the present invention. Furthermore, the deflection element 4 also functions as a directional aperture 18, illuminating only the first region 5 of the confocal chromatic measurement lens 6, so that stray light does not affect the second region 11.

[0039] Furthermore, Figure 2 shows the measurement surface 28 where the focal points of the measurement light 10 at different wavelengths 29, 30, and 31 are located.

[0040] Figure 3 shows a further embodiment of the confocal chromatic ray distance measurement system according to the present invention. This system comprises a line light source 2 and an aperture 3 used to generate a band of light in the X direction. Half of the aperture of the irradiating light 1 is directed only to a first region 5 of the confocal chromatic measurement lens 6 via a deflection element 4 in the form of a mirror, and the irradiating light 1 reaches the object to be measured 9 after passing through the first region 5. The confocal chromatic measurement lens 6 has two aspherical lenses 15 and 16 arranged concentrically, which function as both the illumination optical system and the imaging optical system. However, these do not necessarily have to be aspherical lenses; other useful types of lenses can also be used.

[0041] The measurement light 10 reflected by the object to be measured 9 passes only through the second region 11 of the confocal chromatic measurement lens 6 and is supplied to the conversion optical system 12 by another deflection element 17 designed as a mirror. The conversion optical system 12 has two optical lenses 19 and 20, which provide an image that is different in size from the aperture 3 and is adjusted for the slit-shaped entrance aperture 13 of the spectrometer 14. In this embodiment, the spectrometer 14 is designed as a two-dimensional Dyson spectrometer and has a Dyson lens 23 and a concave diffraction grating 24 in addition to the entrance aperture 13. The spectrometer 14 may have structures other than those shown in the illustration. Therefore, in this embodiment, the irradiation beam path and the imaging beam path are separated from each other, and a single confocal chromatic measurement lens 6 is provided. Furthermore, in this embodiment, similar to the embodiments in Figures 1 and 2, the optical axis 26 of the confocal chromatic measurement lens 6 coincides with the distance axis 27. Furthermore, Figures 1 to 3 clearly show that the aperture 3, the confocal chromatic measurement lens 6, the conversion optical system 12, and the entrance aperture 13 are located on a common virtual (imaginary) optical axis 26a.

[0042] The embodiments described above show a confocal chromatic measurement lens 6 having two lenses 15 and 16, but this configuration is not necessarily required. The confocal chromatic measurement lens 6 may have only one lens or two or more lenses.

[0043] Figure 4 shows a schematic diagram of the theoretical beam model that forms the basis of the method according to the present invention. From this figure, it can be clearly seen that the line light source 2 and the incident aperture 13 of the spectrometer 14 are in exactly the same spatial position and lie on a common virtual optical axis 26a.

[0044] Figure 5 shows one embodiment of the confocal chromatic ray distance measurement system according to the present invention, which is consistent with the confocal chromatic ray distance measurement system shown in Figure 1. The main difference is that the three individual line light sources (2, 2a, 2b) are arranged, each with its own aperture (3, 3a, 3b). The illumination beam may be generated by a single light source having multiple apertures (for example, multiple slit apertures) or by individual floodlights.

[0045] Preferably, the line light sources (2, 2a, 2b) are offset in parallel, resulting in the existence of three adjacent measurement surfaces (28, 28a, 28b). Furthermore, the spectrometer (14) has a plurality of slit openings (13) corresponding to the number of exit openings (3, 3a, 3b) or the number of irradiation lines. Furthermore, please refer to the description of the above embodiment, which is similarly applied to the confocal chromatic ray distance measurement system shown in Figure 5.

[0046] Figure 6 shows the assignment of measurement distance (z) to the position m of the light ray on the matrix for each measurement surface (28, 28a, 28b) (32, 32a, 32b). However, the representation here is simplified, and the measurement positions are shown as individual measurement positions in the x-axis direction, with only the z-axis direction shifted. To fully map this assignment, we need to consider the x-axis direction.

[0047] Figure 7 shows the profile of the object being measured (9) imaged on the region detector (22), which is recorded based on three measurement surfaces (28, 28a, 28b).

[0048] Furthermore, Figure 8 shows three spectral ranges (34, 34a, and 34b), where the measurement signals from the associated measurement surface are discrete at the y-position for each spectral range. It is clear that the spectra from multiple adjacent incident apertures 13 are imaged in different regions of the region detector (22) because they have different angles of incidence to the grating. It is clear that the resulting overlapping spectral ranges (34, 34a, 34b) can cause problems with assignment in a monochrome region detector (22) because the color information necessary to clearly define the assignments is lost.

[0049] However, if a multi-color or hyperspectral region detector (22) is used instead of a monochromatic detector, it becomes possible to distinguish between them.

[0050] When viewing the spectral image of each incident aperture 13 across the entire spectrum (see Figure 8), it is observed that each incident aperture 13 generates a separate spectral image for the spectrometer (14) because the incident angles to the diffraction grating 24 are different. Furthermore, since these spectral ranges overlap significantly, it is desirable to satisfy the following boundary conditions during evaluation. 1. By using a multicolor or hyperspectral region detector (22) in the spectrometer (14), the corresponding incident aperture 13, i.e., the measurement plane (y position) at any measurement point, is defined on the detector based on the incident wavelength. This information can be used to create a calibration chart corresponding to the measurement surface. 2. The irradiation is appropriately controlled to project the light at various display levels over time. In this way, evaluation can be performed using a corresponding calibration table based on the selected light source. 3. Since clearly distinguishable measurement profiles are expected to remain within their respective regions using a monochrome sensor, the spatial ranking along the m-axis will always remain constant during the measurement task. To achieve this, it is necessary to ensure that the images of the two profiles on the detector do not overlap.

[0051] For further advantageous embodiments of the apparatus and method according to the present invention, please refer to the general portion of the specification and the appended claims to avoid repetition.

[0052] Finally, the above-described embodiments of the apparatus and method according to the present invention are for illustrative purposes only and are not limited to the claimed method. [Explanation of Symbols]

[0053] 1 ···Irradiation light 2, 2a, 2b...Line light source 3, 3a, 3b...opening 4...deflection element 5. First region (measuring lens) 6. Confocal chromatic measuring lenses 7. Optical lenses 8. Optical lenses 9 ···Object to be measured 10 ··· Measuring light 11 ···Second area (measuring lens) 12 ···Conversion Optics 13, 13a, 13b...Incidence aperture 14...Spectrometer 15...lens 16...lens 17...deflection element 18...Directional opening 19...Optical lenses 20... Optical lenses twenty one 22 ··· Region detector 23 ···Dyson lens 24...Diffraction grating twenty five 26...Optical axis (measuring lens) 26a...Virtual optical axis 27...distance axis 28, 28a, 28b...Measurement surface 29...Wavelength 1 30...Wavelength 2 31...Wavelength 3 32, 32a, 32b ···m=f(z,x,y), where x and y are constants. 33, 33a, 33b... Colorization Profiles 34, 34a, 34b... spectral range m ··· Light region detector n-column region detector x ···Position along the light ray y ···Lateral position on the projection plane z ... distance measurement point from the measuring lens

Claims

1. A confocal chromatic ray distance measurement system using a confocal chromatic aberration method, comprising a line light source (2), a slit aperture (3), a confocal chromatic measurement lens (6), and a two-dimensional spectrometer (14), The irradiation beam path extends from the line light source (2) to the object to be measured (9) through the slit opening (3) and the first region (5) of the confocal chromatic measurement lens (6), The imaging beam path extends from the object to be measured (9) to the two-dimensional spectrometer (14) via the second region (11) of the confocal chromatic measurement lens (6), The two-dimensional spectrometer (14) is a Dyson spectrometer having a slit-shaped incident aperture (13), The confocal chromatic measurement lens (6) has at least two optical lenses (7, 8), The optical lenses (7, 8) of the confocal chromatic measuring lens (6) are arranged concentrically with respect to each other. The optical axis (26) of the confocal chromatic measuring lens (6) coincides with the distance axis (27) of the confocal chromatic ray distance measuring system. The slit aperture (3), the confocal chromatic measurement lens (6), and the incident aperture (13) of the two-dimensional spectrometer (14) are located on a common virtual optical axis (26a). A confocal chromatic ray distance measurement system characterized in that a deflection element is arranged in the irradiation beam path between the slit opening (3) and the confocal chromatic measurement lens (6), and the deflection element functions as a directional opening (18), so that the irradiation light (1) emitted from the line light source (2) is incident on the confocal chromatic measurement lens (6) only in the first region (5).

2. The confocal chromatic ray distance measurement system according to claim 1, characterized in that a single confocal chromatic measurement lens (6) is arranged.

3. The confocal chromatic ray distance measurement system according to claim 1, characterized in that the linear light source (2) emits a continuous white ray.

4. The confocal chromatic ray distance measurement system according to claim 1, characterized in that the line light source (2) emits two or more irradiation lines as irradiation light, and / or a plurality of line light sources (2) are arranged such that each of the line light sources (2) emits at least one irradiation line as irradiation light.

5. The confocal chromatic ray distance measurement system according to claim 1, characterized in that the ray light source (2) is positioned on the incident side of the focal point of the confocal chromatic measurement lens (6).

6. The confocal chromatic ray distance measurement system according to claim 1, characterized in that the deflection element is designed as a mirror or a beam splitter.

7. The aforementioned confocal chromatic ray distance measurement system includes a conversion optical system (12), The conversion optical system (12) is positioned between the confocal chromatic measurement lens (6) and the two-dimensional spectrometer (14) in the imaging beam path, or between the line light source (2) and the confocal chromatic measurement lens (6) in the irradiation beam path. The conversion optical system (12) has at least one optical lens (19, 20), The confocal chromatic ray distance measurement system according to claim 1, characterized in that at least one optical lens (19, 20) is arranged concentrically with the confocal chromatic measurement lens (6) in the basic optical model and / or is located on a common virtual optical axis (26a) together with the confocal chromatic measurement lens (6).

8. The confocal chromatic ray distance measurement system according to claim 1, characterized in that the two-dimensional spectrometer (14) has a Dyson lens (23), a concave diffraction grating (24), and a region detector (22).

9. The confocal chromatic ray distance measurement system according to claim 8, characterized in that the diffraction grating (24) is a blazed diffraction grating and / or has an equally spaced parallel structure.

10. The confocal chromatic ray distance measurement system according to claim 1, characterized in that the width of the incident aperture (13) is 20 μm or less.

11. The confocal chromatic ray distance measurement system according to claim 1, characterized in that the irradiation beam path and the imaging beam path between the confocal chromatic measurement lens (6) and the object to be measured (9) extend at angles ranging from 45° to 90° relative to each other.

12. A confocal chromatic ray distance measurement method using a confocal chromatic aberration method, comprising using a confocal chromatic ray distance measurement system described in any one of claims 1 to 11, The illumination light (1) is directed from the line light source (2) to the object to be measured (9) via the slit opening (3) and the first region (5) of the confocal chromatic measurement lens (6) which is a colored illumination surface. The spectrally converted measurement light (10) is guided from the object to be measured (9) to the two-dimensional spectrometer (14) via the second region (11) of the confocal chromatic measurement lens (6). The distance is determined by performing a spectral analysis of the measurement light (10). A confocal chromatic ray distance measurement method characterized in that the Dyson spectrometer having the slit-shaped incident aperture (13) is used as the two-dimensional spectrometer (14).

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