Source: https://patents.google.com/patent/EP1794540B1/en
Timestamp: 2020-08-10 17:12:05
Document Index: 165253303

Matched Legal Cases: ['art 30', 'art 40', 'art 30', 'art 40', 'art 30', 'art 40', 'art 30', 'art 40', 'art 40', 'art 40', 'art 40', 'art 40', 'art 40', 'art 40', 'art 40']

EP1794540B1 - Optical measuring device for measuring several surfaces of a measuring object - Google Patents
Optical measuring device for measuring several surfaces of a measuring object Download PDF
EP1794540B1
EP1794540B1 EP20050777826 EP05777826A EP1794540B1 EP 1794540 B1 EP1794540 B1 EP 1794540B1 EP 20050777826 EP20050777826 EP 20050777826 EP 05777826 A EP05777826 A EP 05777826A EP 1794540 B1 EP1794540 B1 EP 1794540B1
EP20050777826
EP1794540A1 (en
2004-09-22 Priority to DE200410045808 priority Critical patent/DE102004045808A1/en
2005-07-22 Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
2005-07-22 Priority to PCT/EP2005/053578 priority patent/WO2006032561A1/en
2007-06-13 Publication of EP1794540A1 publication Critical patent/EP1794540A1/en
2015-04-22 Publication of EP1794540B1 publication Critical patent/EP1794540B1/en
The invention relates to an optical measuring device for measuring a plurality of surfaces of a measured object by means of an arrangement of optical elements. Furthermore, the invention relates to a use of the optical measuring device as a lens for the measurement object.
From the US 2004 / 075842A1 an interferometer is known in which a conical surface and a shaft wall can be measured by rotating the interferometer about its longitudinal axis.
From the US B1-6,462,815 an interferometer is known in which a conical surface and a shaft wall can be measured by rotating the interferometer about its longitudinal axis.
From the DE 101 31 778 A1 an optical measuring device is known, which is designed to generate an all-round image of a conical surface for interferometric measurement by means of a lens system.
Among other things, interferometric systems are suitable for non-contact investigations of surfaces of various measurement objects. For detecting the surface contour of an object to be examined, an object beam from a light source of the interferometer hits the surface at the area to be measured. The object beam reflected from the surface is fed to a detector of the interferometer and together with a reference beam forms an interference pattern, from which the path length difference of the two beams can be derived. This measured path length difference of the two beams corresponds to the topography change of the surface.
In particular, with a white light interferometer, in which the light source emits a short-coherent radiation, it is also possible to scan the measurement object by means of depth scanning. As For example, in the non-prepublished patent application DE-103 25 443.9 explained, the short-coherent radiation is split over a beam splitter into an object beam and a reference beam. The object surface to be measured is imaged via an objective onto an image recorder, for example onto a CCD camera ("charge-coupled device" camera), and superimposed by the reference wave formed by the reference beam. The depth scan may be performed by moving a reference mirror reflecting reference mirror or lens relative to the measuring device. When moving the object, the image plane of the object and the reference plane are in the same plane. During depth scanning, the object remains rigid in the field of view of the CCD camera and the object is moved only in the depth axis relative to the reference plane. In this way, measurements of technical surfaces with a depth resolution in the range of a few nanometers can be measured. Technical basics of this measurement method can also be found in the article " Three-dimensional sensing of rough surfaces by coherence radar "(T. Dresel, G. Häusler, H. Venzke, Appl. Opt. 31 (7), pp. 919-925, 1992 ).
If the area of the object to be measured is not a uniform, flat plane, then a special objective is required for measuring the object to be measured. Because with each measurement process, care must be taken that the rays impinge as vertically as possible on the surfaces to be measured during scanning. From the DE-101 31 778 A1 For example, an arrangement of optical elements is known with which even curved surfaces can be measured. So z. B. the Figure 1c from the cited document, as well as hard-to-reach measuring surfaces such as the inner surface of a cylinder or a bore can be measured with the panoramic optics presented there. By means of a deflection prism in the panoramic optics, the rays directed perpendicular to the inner surface of the bore. In a further embodiment, the panoramic optics, as in Figure 1d shown in the cited document, be designed for an inner conical surface at a transition region of the bore. With the help of the special optics, the parallel rays impinging on the optics are converted on the object side into rays which are perpendicular to the conical surface, ie the rays are fanned out. In practice, however, it is advantageous if both surfaces, ie the inner surface of a bore and caused by a further narrowing of the bore, inner conical surface can be measured simultaneously. Such requirements arise, for example, when the position of a guide bore is measured to a conical valve seat. According to the state of the art, two or more panoramic optics may be arranged and designed in such a way that a flattened image can be generated simultaneously, apart from a surface area of at least one further surface area. In the reference light path, at least one further reference plane can then likewise be arranged corresponding to the number of further surface regions for generating different optical path lengths. Thus, the position of the guide bore can be measured to a spatially separated valve seat.
With only one lens so the measurement of the two surfaces is not possible. A simple combination of the two embodiments with a deflection mirror ( Fig. 1c ) and with a beam-fanning appearance ( Fig. 1d ) of the prior art does not lead to success, since the beams would detect either only the inner surface of the bore or only the inner conical surface, depending on the order of installation of the two optical elements.
The optical measuring device according to the invention with the features specified in claim 1 and the use according to claim 7 have over the prior art has the advantage that the measurement of several, difficult to access surfaces of a measurement object is made possible. Particularly advantageously, the different measuring surfaces such as conical surfaces and inner surfaces of a bore can be measured quickly and without changing the measuring device. The optical measuring device can also be used as a special objective for the measurement object in a measurement setup of a known interferometer or in an autofocus sensor. Advantageous developments of the interferometric measuring device are specified in the subclaims and described in the description.
FIG. 1 a first embodiment of an arrangement of the optical elements in the measuring device,
FIG. 2 a second embodiment of an arrangement of the optical elements in the measuring device,
FIG. 3 an interferometric measuring structure with the measuring device according to the invention as a special lens, and
FIG. 4 an image recorder with evaluation software for a double correlogram.
A first embodiment of the measuring device 1 according to the invention with an arrangement of optical elements shows FIG. 1 , In this example, the measuring object 15 is a guide bore whose diameter changes over a transition region from a constantly higher value to a constantly lower value. The transition region itself has a continuous narrowing of the bore, whereby the surface shape of a section of an inner conical surface forms. Such a geometry corresponds to that of a guide bore with a conical, ie conical-shaped valve seat. The inner wall corresponds to a first surface 5 and the conical valve seat a second surface 10 of the measured object to be measured 15. According to the invention as optical elements at least one beam splitter 20 and a lens system 25 are provided for measuring the inner wall of the guide bore and the conical valve seat, wherein a first part 30 of the incident on the beam splitter 20 light rays 35 is directed perpendicular to the first surface 5 of the measurement object 15, and a second part 40 of the incident on the beam splitter 20 light rays 35 on the beam splitter 20 downstream lens system 25 occurs and the lens system 25 perpendicular to the second surface 10 is directed. The beam splitter 20 deflects the first part 30 of the light beams 35 incident on the beam splitter 20 advantageously at right angles to the direction of incidence. The second part 40 of the light beams 35 incident on the beam splitter 20 is directed onto the lens system 25 without any deflection.
In order that the light beams 35 can be divided into the first 30 and the second 40 part, the beam splitter 20 is semi-light permeable, ie, the first part 30 of the light beams 35 is reflected at the beam splitter 20, while the second part 40 penetrates the beam splitter 20. In FIG. 1 the beam splitter 20 is a semitransparent prism. Corresponding to the axisymmetric shape of the measurement object 15, the beam splitter 20, in this case the prism, and / or the lens system 25 also has an axially symmetrical shape. The lens system 25 fan-shapes the second portion 40 of the beams 35 so that it perpendicularly occurs at each location on the conical valve seat. Both the first part 30 and the second part 40 of the light beams 35 split by the beam splitter 20 are reflected back on the first surface 5 or second surface 10 of the measuring object 15 to the side of the measuring device 1 incident to the light beam.
The optical elements are usually arranged in a tube 45, in particular in an outlet region of the tube 45. At the points at which the first 30 or the second part 40 of the light beams 35 exit from the tube or re-enter the tube after the respective reflection, the tube consists of an optically transparent material or is entirely omitted to form a recess. For reasons of clarity, the optically transparent material or the recess is not shown in the figures.
In the FIG. 2 a second embodiment of the measuring device 1 is shown. It differs from the first embodiment in that the beam splitter 20a is formed by a hollow cone, ie, the beam splitter 20a is a half-light transmissive disc having a recess in the form of an axisymmetric prism.
The measuring device 1 is suitable for use as a special objective for a measuring object 15 in a measuring setup of a known interferometer, in particular a white light interferometer. A measurement setup according to Michelson is in FIG. 3 and its measuring principle known: In the white light interferometry (short-coherence interferometry), a light source 50 emits a short-coherent radiation. The light is split by a beam splitter 55 of the interferometer into a reference beam 60 and into an object beam 65. The beam splitter 55 of the interferometer is to be distinguished from the beam splitter 20, 20 a of the measuring device 1. The reference beam 60 is further reflected by a reference mirror 70 arranged in the reference light path and passes again via the beam splitter 55 into an image recorder 75, advantageously a CCD or CMOS camera ("complementary metal oxide semiconductor" camera). There, the light waves of the reference beams 60 are superimposed with the light waves of the object beams 65, which in turn were directed and reflected on the first and second surfaces 5, 10 of the measurement object 15 via the special objective arranged in the object light path according to the invention. As already described, the object beams 65 or the light beams 35 incident on the beam splitter 20, 20a of the measuring device 1 are divided according to the invention into a first 30 and second part 40 in order to allow the measurement of two surfaces. Of course, an application of the measuring device 1 as a special lens is also possible in a measuring setup of an autofocus sensor or a laser, heterodyne or other interferometer.
During the measurement, relative movement of the measuring device 1 to the measuring object 15 or vice versa is preferably to be avoided. Therefore, the measuring device 1 is particularly suitable as a special objective of an interferometer with an intermediate image. Such interferometers with the possibility to Generation of the intermediate image are known from the prior art.
Moreover, it is important that when measuring the first 5 and the second surface 10 of the measurement object 15, the two surfaces 5, 10 are not simultaneously in the focus of the image sensor 75. The beams reflected by the two surfaces 5, 10 and transferred into the image recorder 75 would then be superimposed to form a common interference pattern and thus falsify the measured values. Therefore, first the first surface 5 is scanned until it exits the interference region before the second surface 10 enters the interference region and is also scanned. The surfaces 5, 10 can of course also be scanned in reverse order. In order to avoid an overlap of the first 30 and the second part 40 of the light beams 35 in the image sensor 75, attention must be paid to the arrangement of the optical elements of the measuring device 1 with respect to the coherence length of the light beams 35. A coherence length of a wave train means the connection length necessary for interference for an overlap. The optical elements of the measuring device 1 are therefore arranged taking into account the above-described overlapping condition such that the optical paths of the first 30 and the second part 40 of the incident light beams 35 are different at least in the order of a coherence length of the light beams 35. Typical value range of a coherence length in a white light interferometer is about 2 to 14 μm, whereas in a heterodyne interferometer with wavelengths of about 1570 μm used, a coherence length of about 80 μm results.
Alternatively or in addition to the arrangement of the measuring device 1 with different path lengths for the first 30 and second part 40 of the light beams 35, a disturbing overlap of the two partial beams 30, 40 in the image recorder 75 thereby prevents the beam splitter 20, 20a is electrically or magnetically controlled to selectively vary its transmission and reflection property. Thus, the light path of the first 30 or the second part 40 of the light beams 35 is temporarily hidden.
In this context, it is advantageous to use an image recorder 75 with evaluation software for a double correlogram 80. Since, according to the invention, the optical measuring device 1 makes it possible to measure a plurality of surfaces 5, 10 of a measuring object 15, the image recorder 75 must evaluate the partial beams reflected from different surfaces separately. As in FIG. 4 illustrates, the interference pattern generated in the image sensor 75 is evaluated separately according to its intensity 85 and 90 after position, so that with the aid of the evaluation software, two successive correlograms 95, 100 are formed.
In summary, a division of the light beams 35 into a first 30 and second part 40 in the measuring device 1 makes it possible to measure a plurality of surfaces 5, 10 of a measuring object 15. The arrangement of the optical elements in particular allows the measurement of an inner surface of a cylinder and a conical-shaped surface with only one measuring device. 1
Measurement arrangement comprising a measurement object (15) and an optical measurement device (1) for measuring a first (5) and a second surface (10) of a measurement object (15) by means of an arrangement of optical elements, the measurement object having a guide bore whose internal wall corresponds to the first surface (5), and the second surface (10) corresponding to a conically designed, conical valve seat of the measurement object (15) to be measured,
at least a beam splitter (20; 20a) and a lens system (25) are arranged as optical elements such that a first portion (30) of the light beams (35) incident on the beam splitter (20; 20a) is directed perpendicular to the first surface (5) of the measurement object (10), and a second portion (40) of the light beams (35) incident on the beam splitter (20; 20a) impinges on the lens system (25) arranged downstream of the beam splitter (20; 20a) and is directed vertically onto the second surface (10) via the lens system (25), the beam splitter (20; 20a) being an axially symmetric conical prism or a hollow cone, and the lens system (25) fanning out conically the second portion (40) of the incident light beams (35), the optical elements being arranged such that the optical paths of the first (30) and the second portion (40) of the incident light beams (35) differ at least by the order of magnitude of a coherence length of the light beams (35).
Measurement arrangement according to Claim 1, characterized in that the beam splitter (20; 20a) deflects the first portion (30) of the light beams (35) incident on the beam splitter (20; 20a) at right angles to the incidence direction, and/or directs the second portion (40) of the light beams (35) incident on the beam splitter (20; 20a) onto the lens system (25) without any deflection.
Measurement arrangement according to Claim 1 or 2, characterized in that the transmission and reflection of the beam splitter (20; 20a) can be varied by electrical or magnetic control.
Measurement arrangement according to Claim 3, characterized in that the light path of the first (30) or the second portion (40) of the light beams (35) can be faded out in the short term by the electrical or magnetic control.
Measurement arrangement according to one of the preceding claims, characterized in that the beam splitter (20; 20a) and/or the lens system (25) have/has an axially symmetric shape.
Measurement arrangement according to one of the preceding claims, characterized in that the optical elements are arranged in a tube (45), in particular in an exit area of the tube (45).
Use of the measurement arrangement having the optical measurement device (1) according to one of the preceding claims, characterized in that the measurement device (1) is used as a special objective for the measurement object (15) in a measurement setup of an autofocus sensor or of an interferometer known per se, in particular a laser, heterodyne or white light interferometer.
Use of the measurement arrangement having the optical measurement device (1) according to Claim 8, characterized in that the measurement device (1) is used together with an image recorder (75) having evaluation software for a double correlogram (80).
EP20050777826 2004-09-22 2005-07-22 Optical measuring device for measuring several surfaces of a measuring object Active EP1794540B1 (en)
DE200410045808 DE102004045808A1 (en) 2004-09-22 2004-09-22 Optical measuring device for measuring a plurality of surfaces of a measurement object
PCT/EP2005/053578 WO2006032561A1 (en) 2004-09-22 2005-07-22 Optical measuring device for measuring several surfaces of a measuring object
EP1794540A1 EP1794540A1 (en) 2007-06-13
EP1794540B1 true EP1794540B1 (en) 2015-04-22
ID=34981306
EP20050777826 Active EP1794540B1 (en) 2004-09-22 2005-07-22 Optical measuring device for measuring several surfaces of a measuring object
US (1) US7643151B2 (en)
EP (1) EP1794540B1 (en)
JP (1) JP2008513751A (en)
KR (1) KR20070062527A (en)
CN (1) CN101023319A (en)
BR (1) BRPI0514373A (en)
DE (1) DE102004045808A1 (en)
RU (1) RU2007115154A (en)
WO (1) WO2006032561A1 (en)
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DE102008012461B4 (en) * 2008-03-04 2013-08-01 Minebea Co., Ltd. Device for optically scanning the inner surface of a bore
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DE102008001473B3 (en) 2008-04-30 2009-12-31 Robert Bosch Gmbh Optical arrangement for illuminating a measurement object, interferometric arrangement for measuring surfaces of a measurement object
DE202009018893U1 (en) 2009-03-26 2014-09-11 Robert Bosch Gmbh Self-leveling multi-line 360 ° laser device
CN101839697A (en) * 2010-04-20 2010-09-22 天津大学 Optical system for use in shaft hole diameter measurement
DE102012212785A1 (en) * 2012-07-20 2014-01-23 Robert Bosch Gmbh Optical probe and method for optical measurement of inside and outside diameters
US20150369581A1 (en) 2012-12-20 2015-12-24 Marposs Societa' Per Azioni System and method for checking dimensions and/or position of an edge of a workpiece
WO2015189177A1 (en) 2014-06-13 2015-12-17 Marposs Societa' Per Azioni System and method for checking position and/or dimensions of an edge of a workpiece
SI2957859T1 (en) * 2014-06-18 2018-12-31 Sturm Maschinen- & Anlagenbau Gmbh Test device and method for testing the interior walls of a hollow body
CN105509639B (en) * 2014-09-24 2019-01-01 通用电气公司 For the measuring system and measurement method of measure geometry feature
JP2016075577A (en) * 2014-10-07 2016-05-12 株式会社東京精密 Shape measurement device
WO2016084638A1 (en) * 2014-11-25 2016-06-02 並木精密宝石株式会社 Optical inner surface measurement device
US10598490B2 (en) 2017-05-03 2020-03-24 Stanley Black & Decker Inc. Laser level
CN107976155B (en) * 2017-11-23 2019-10-25 中国科学技术大学 A kind of engine air inside wall of cylinder detection device and method based on digital hologram interference
CN111213053A (en) * 2018-07-27 2020-05-29 合刃科技（深圳）有限公司 Device and method for detecting inner wall of micro-fine tube based on coherent light
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US6781699B2 (en) 2002-10-22 2004-08-24 Corning-Tropel Two-wavelength confocal interferometer for measuring multiple surfaces
DE10301607B4 (en) * 2003-01-17 2005-07-21 Robert Bosch Gmbh Interference measuring probe
2004-09-22 DE DE200410045808 patent/DE102004045808A1/en not_active Withdrawn
2005-07-22 WO PCT/EP2005/053578 patent/WO2006032561A1/en active Application Filing
2005-07-22 CN CN 200580031788 patent/CN101023319A/en not_active IP Right Cessation
2005-07-22 RU RU2007115154/28A patent/RU2007115154A/en not_active Application Discontinuation
2005-07-22 US US11/662,963 patent/US7643151B2/en active Active
2005-07-22 BR BRPI0514373 patent/BRPI0514373A/en not_active IP Right Cessation
2005-07-22 KR KR1020077006584A patent/KR20070062527A/en not_active Application Discontinuation
2005-07-22 EP EP20050777826 patent/EP1794540B1/en active Active
2005-07-22 JP JP2007531733A patent/JP2008513751A/en not_active Withdrawn
BRPI0514373A (en) 2008-06-10
RU2007115154A (en) 2008-10-27
KR20070062527A (en) 2007-06-15
US7643151B2 (en) 2010-01-05
JP2008513751A (en) 2008-05-01
WO2006032561A1 (en) 2006-03-30
EP1794540A1 (en) 2007-06-13
CN101023319A (en) 2007-08-22
US20080259346A1 (en) 2008-10-23
DE102004045808A1 (en) 2006-04-06
US8934104B2 (en) 2015-01-13 Method and arrangement for robust interferometry for detecting a feature of an object
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