KR102285818B1 - Apparatus for monitoring three-dimensional shape of target object capable of auto focusing in real time - Google Patents

Abstract

The present invention matches the difference according to the optical path between the reference mirror and the measurement object in real time in measuring the three-dimensional shape according to the method of focusing and forming an image by transferring the optical system or measurement system equipped with the reference mirror. A three-dimensional shape measuring device capable of measuring a three-dimensional shape of a measurement object by using the same, and a method for measuring a three-dimensional shape of a measurement object using the same.

Description

A three-dimensional shape measuring device capable of auto-focusing in real time and measuring a three-dimensional shape of a measurement object {Apparatus for monitoring three-dimensional shape of target object capable of auto focusing in real time}

The present invention relates to a three-dimensional shape measuring device for measuring a three-dimensional shape of a measurement object capable of autofocus in real time, and more particularly, to a reference mirror and a reference mirror based on a light splitter by transferring an optical system or a measurement system equipped with a reference mirror. In the three-dimensional shape measurement according to the method of matching the optical path difference of the measurement object, the measurement object according to the method of focusing and image forming by matching the difference according to the optical path between the reference mirror and the measurement object in real time To a three-dimensional shape measuring device capable of measuring the three-dimensional shape of and a method for measuring the three-dimensional shape of an object to be measured using the same.

Methods for measuring the fine surface shape of precision parts include stylus type measurement method, scanning electron microscope measurement method, scanning probe microscope measurement method, and phase shifting interferometry. ) measurement method, White-Light Scanning Interferometry measurement method, Confocal Scanning Microscope measurement method, and the like.

These measurement methods mainly measure geometric shapes on a two-dimensional plane, such as circles, lines, angles, and line widths, or inspect pattern defects, foreign substances, and asymmetry. It is based on a probe system composed of an image pickup device and image processing technology.

Among these measurement methods, the white light scanning interferometer measurement method and the optical phase shift interferometer measurement method are three-dimensional measurement of microscopic shapes such as semiconductor pattern measurement, surface roughness measurement of soft materials, BGA (Ball Grid Array) ball measurement, laser marking pattern measurement, and via hole measurement. It is in the spotlight as a non-contact measurement method that is widely applied in general.

Although these two measurement methods are based on different measurement principles, they can be implemented in the same optical and measurement system except that they use multiple wavelengths and monochromatic wavelengths, so that these two measurement methods can be used together in a commercialized measurement system.

These measurement methods are based on optical interference in which light is expressed in a bright and dark form according to the difference in the distance between the two lights when the light that starts at the same time from an arbitrary reference point moves through different optical paths and then merges. use the signal

As a prior document related to such a white light interferometer, Korean Patent Registration No. 10-0598572 (July 2006) discloses a process of applying a transparent thin film layer on the surface of an opaque metal layer in a semiconductor and liquid crystal display (LCD) manufacturing process. White-light scanning interferometry (WSI) has been proposed to measure the thickness of the transparent thin film layer or information on its surface shape.

The basic measurement principle of the white light scanning interferometry is to use the short coherence length characteristic of white light. Using the principle that an interference signal is generated only when experiencing an optical path difference, the measurement object is measured by moving the measurement object in a small interval of several nanometers in the direction of the optical axis with a transport means such as a PZT actuator. When the interference signal at each measurement point in the area is observed, a short interference signal is generated at the point where each point has the same optical path difference as the reference mirror. Information on the three-dimensional shape is obtained, and the surface shape of the thin film layer is measured from the obtained three-dimensional information.

1 is a view showing a surface shape measuring apparatus using white light scanning interferometry. As shown in this figure, the conventional surface shape measuring apparatus includes a light source, a light splitter, an interference module, an imaging unit, a transfer unit, and a control unit. .

The white light interferometer according to the prior art has a coherent interference section of about 4 to 20 um and a period of an interference fringe of about 0.3 um. Interference fringes must be acquired over the entire height while transporting, which increases the time required for measurement.

In addition, FIG. 2 is another configuration diagram of a conventional three-dimensional shape measuring device, in which the illumination light from the light source is split through a beam splitter, irradiated to the reference plane and the measurement target surface of the measurement object, respectively, and reflected from the reference mirror and the measurement surface They are combined through a beam splitter, and the combined interference fringes are detected through an imaging device such as a CCD camera, and the phase of the interference fringes is calculated in the control computer, or the point of maximum coherence is extracted from the envelope of the interference fringes. So measure the height.

Here, the three-dimensional shape measuring device posted at the top in FIG. 2 is a means for adjusting the distance from the measuring surface and the distance from the beam splitter to the reference mirror, and a support means (tilting) for enabling horizontal movement of the reference mirror. stage, etc.) is configured to adjust the distance between the beam splitter and the reference mirror by using the entire support means using an actuator (not shown), and the three-dimensional shape measurement shown at the bottom of FIG. The apparatus (Korea Patent No. 10-1116295, 2012.03.14.) proposes a three-dimensional shape measuring device that can adjust the reflection distance by installing a beam splitter moving means to the beam splitter and adjusting the position of the beam splitter. , according to this, the beam splitter moving means can move a minute distance in the direction toward the reference mirror or the direction toward the measurement object, thereby simplifying the overall structure of the three-dimensional shape measuring apparatus.

On the other hand, in order to measure the fine surface shape of a plurality of precision parts, before the irradiation of the measurement light for measuring the surface shape, from a reference point (eg, a light splitter, a reference mirror, etc.) to a specific position on the surface of the fine part as a measurement object A process is required to first measure the distance of the reference mirror and match the distance difference according to the optical path between the reference mirror and the measurement object. Corresponds to the method of matching the locus (auto focusing), and after the above process is performed, at least a portion of the three-dimensional shape measuring device including at least one of the light source, the light splitter, and the reference mirror is determined independently. The surface shape can be measured by irradiating the measurement light for measuring the three-dimensional shape and moving (scan) the light splitter or the reference mirror.

Therefore, as the number of objects (samples) to be measured increases, the process of focusing and forming images by matching the respective distances along the optical path between the reference mirror and the measurement object to the measurement object must be carried out quickly. The overall time required to measure each microsurface shape can be reduced, and with the development of IT technology, the reduction of the measurement time is recognized as a more important factor in productivity.

However, in the case of a three-dimensional shape measuring apparatus according to the prior art including the prior art, a separate device for focusing and imaging by quickly matching the respective distances along the optical path between the reference mirror and the measurement object is not provided. There is room for improvement, and therefore, a device capable of reducing the measurement time of the microsurface shape through the process of matching the distance according to the optical path between the reference mirror and the measurement object more quickly, and a more improved device using the same The need for the development of a three-dimensional shape measuring method is continuously demanded.

Korean Patent Registration No. 10-0598572 (July 7, 2006) Korean Patent Registration No. 10-1116295 (2012.03.14.)

The present invention has been devised to solve the above-described problem, and preferentially measures the distance from a specific reference point (eg, a light splitter, a reference mirror, etc.) in a three-dimensional shape measuring device to a specific position on the surface of an object to be measured, The three-dimensional shape measurement is carried out according to the method of transporting the object or transferring the optical system or measurement system equipped with the reference mirror to match the distance difference according to each optical path between the reference mirror and the measurement object from the specific reference point. It is an object of the invention to provide a three-dimensional shape measuring device capable of measuring the three-dimensional shape of the interferometer in real time by making it possible to more quickly match the distance difference according to each optical path between the reference mirror and the measurement object do.

Another object of the present invention is to provide a novel measuring method for measuring a three-dimensional shape of an object to be measured using the three-dimensional shape measuring apparatus according to the present invention.

To this end, the present invention provides a light source unit 100 that emits light and is positioned in one direction of the first light splitter 200 below; a first light splitter 200 for splitting the light from the light source unit 100 into a measurement object 600 and a reference mirror 300 below; a reference mirror 300 located in the other direction of the first light splitter opposite to the light source unit, the divided light from the first light splitter 200 is irradiated and reflected back to the first light splitter; Taking pictures of an interference fringe in which the light irradiated from the light source unit 100 to the surface of the object to be measured and reflected, and the light reflected from the reference mirror 300 and light along the optical path passing through the first light splitter 200 are combined part 500; and a separate light independent of the light emitted from the light source unit 100, thereby reaching the reference mirror from the first light splitter 200 and reflected light and the first light splitter 200 measured A three-dimensional shape measuring device including; a displacement measuring unit 400 for measuring a displacement measurement value according to an optical path between light reaching the object 600 and reflected, wherein the displacement measuring unit 400 includes a light source unit 100 Displacement measurement light source 411 for emitting a separate light independent of the light emitted from; and a dispersive interferometer spectrometer 413 that is emitted from the displacement measurement light source 411 and reaches each of the measurement object 600 and the reference mirror 300 and is reflected back to disperse the merged light, thereby measuring the interference information of the dispersed light. ); includes; the distributed displacement interferometer 410 including; the light emitted from the displacement measurement light source 411 in the distributed displacement interferometer 410 passes through the first light splitter 200 to the measurement object and the reference mirror It provides a three-dimensional shape measuring apparatus, characterized in that after being irradiated to the scattering interferometer spectrometer (413) again through the first optical splitter (200).

As an embodiment, the first light splitter 200 may be moved horizontally or vertically between the light source unit 100 and the reference mirror 300 .

As an embodiment, the reference mirror 300 may be horizontally movable in parallel with the optical path between the light source unit 100 and the first light splitter 200 .

As an embodiment, the displacement measuring unit 400 measures the light emitted from the displacement measuring light source 411 in the distributed displacement interferometer 410 in the optical path between the light source unit 100 and the first optical splitter 200 . The light emitted from the displacement measurement light source 411 in the distributed displacement interferometer 410 reaches the measurement object and the reference mirror through the first light splitter 200, further including a second light splitter 420 for splitting. and can be reflected back to reach the distributed interferometer spectrometer 413 in the distributed displacement interferometer 410 through the first optical splitter 200, and in this case, the displacement measurement light source 411 in the distributed displacement interferometer 410 ) is located in a direction perpendicular to the optical path between the light source unit 100 and the first light splitter 200 and emits a separate light independent of the light emitted from the light source unit 100 in the second light splitter 420 direction. can do.

As an embodiment, the displacement measuring unit 400 is the light emitted from the displacement measuring light source 411 in the distributed displacement interferometer 410 in the optical path between the photographing unit 500 and the first optical splitter 200 . A second light splitter 420 to split It arrives and is reflected again and can reach the distributed interferometer spectrometer 413 in the distributed displacement interferometer 410 through the first optical splitter 200, and in this case, the displacement measurement light source in the distributed displacement interferometer 410 411 is located in a direction perpendicular to the optical path between the photographing unit 500 and the first light splitter 200 and separates the light independent from the light emitted from the light source unit 100 to the second light splitter 420 . ) can be emitted in the direction of

As an embodiment, between the displacement measurement light source 411 and the second light splitter 420 in the distributed displacement interferometer 410, the displacement measurement light source 411 is emitted from the displacement measurement light source 411 and is reflected after reaching the measurement object to be reflected to the first An optical splitter 412 in the dispersed displacement interferometer that splits the reflected light returning through the splitter and the second splitter into the dispersed interferometer spectrometer 413 in the dispersed displacement interferometer 410 may be additionally included, in this case The dispersive interferometer spectrometer 413 emits from the displacement measurement light source 411, reaches the measurement object, is reflected, and passes through the first light splitter, the second light splitter, and the dispersed displacement interferometer light splitter 412. It may include a distributed displacement spectroscopic device 415 for dispersing and a distributed displacement optical measuring device 414 for measuring the light dispersed from the spectroscopic device.

As an embodiment, the three-dimensional shape measuring apparatus according to the present invention may be any one selected from among Michelson, Mirau, and Linick type.

As an embodiment, at least a part of the distributed displacement interferometer 410 in the three-dimensional shape measuring device may be configured in an optical fiber type.

As an embodiment, in the three-dimensional shape measuring device, from the displacement measurement value obtained by the displacement measurement unit 400 , the light emitted from the displacement measurement light source 411 reaches the reference mirror from the first light splitter 200 . to independently move the measurement object 600 to match the respective distances along the optical path between the reflected light and the light reflected by reaching the measurement object 600 from the first light splitter 200 Alternatively, the measurement object 600 is fixed and at least a portion of the three-dimensional shape measuring device including at least one of the light source unit 100, the first light splitter 200, and the reference mirror 300 can be independently moved. may additionally include; in this case, the control unit 700 may additionally move the position of the first light splitter 200 or the reference mirror 300 .

In addition, the present invention provides a method for measuring a three-dimensional shape of an object to be measured using the three-dimensional shape measuring apparatus according to the present invention.

In the three-dimensional shape measuring apparatus according to the present invention, by introducing the displacement measuring unit 400 including the distributed displacement interferometer 410 to the existing shape measuring interferometer, it is possible to more quickly focus the measurement object, and It is possible to provide a three-dimensional shape measuring device capable of measuring a three-dimensional shape.

More specifically, in a three-dimensional shape measuring device in which a three-dimensional shape measurement is performed according to a method of focusing and forming an image by transporting an optical system or a measuring system equipped with a reference mirror or transporting a measuring object, By introducing the displacement measuring unit 400 including the displacement interferometer 410, the light irradiated from the displacement measuring light source 411 is irradiated to the measurement object and the reference mirror through the first light splitter 200, respectively, and again these By designing the reflected light reflected from the beam to reach the spectrometer through the first beam splitter, the distance difference between the reference mirror and the measurement object from a specific reference point (eg, beam splitter) in the three-dimensional shape measuring device can be matched more quickly. It is possible to provide a three-dimensional shape measuring device capable of measuring the three-dimensional shape of the interferometer in real time.

That is, in order to measure a three-dimensional shape using a conventional interferometer including a reference mirror, the optical system or the measurement system is transferred with respect to the measurement object, or the measurement object is moved with respect to the optical system or the measurement system, and between the reference mirror and the measurement object After matching the distance difference according to the optical path, the shape must be measured by scanning the reference mirror, etc., and the present invention introduces the displacement measuring unit 400 including the distributed displacement interferometer 410 in this process, The distance difference according to each optical path between the reference mirror and the measurement object is quickly measured from a specific reference point in the stereoscopic shape measuring device, and then the measurement object is transported or the optical system or measurement system equipped with the reference mirror is transferred to the distance difference. It is possible to provide a three-dimensional shape measuring device capable of measuring the three-dimensional shape of the interferometer in real time by driving the existing shape measuring interferometer after focusing the measurement object in real time by rapidly matching the .

In addition, the present invention has the advantage of being able to provide a method for more rapidly measuring a three-dimensional shape of an object to be measured using the three-dimensional shape measuring apparatus according to the present invention.

1 is a view showing a surface shape measuring apparatus using a white light scanning interferometry according to the prior art.
2 is a diagram showing the configuration of another three-dimensional shape measuring apparatus according to the prior art and an operation method thereof.
3 is a diagram showing the configuration of a three-dimensional shape measuring apparatus according to an embodiment of the present invention.
4 is a view showing the main configuration of the distributed displacement interferometer 410 in the three-dimensional shape measuring apparatus according to an embodiment of the present invention and the coupling relationship between the light source unit and the second light splitter 420 .
5 is a diagram showing the configuration of a three-dimensional shape measuring apparatus according to another embodiment of the present invention.
6 shows the main configuration of the distributed interferometer spectrometer 413 in the three-dimensional measuring device according to an embodiment of the present invention, and measuring the distance difference along each optical path between the reference mirror and the measurement object to focus and form an image. It is a view showing the path of the light emitted from the displacement measuring light source 411 in the process.
7 shows the main configuration of the distributed interferometer spectrometer 413 in the three-dimensional measuring device according to another embodiment of the present invention, and the distance difference between the reference mirror and the measurement object is measured and focused. It is a view showing the path of the light emitted from the displacement measuring light source 411 in the process of forming an image.
8 is a diagram illustrating the main configuration of the mirror-type three-dimensional shape measuring device according to an embodiment of the present invention and the displacement in the process of focusing and forming an image by measuring the distance difference according to each optical path between the reference mirror and the measurement object. It is a diagram illustrating a path of light emitted from the measurement light source 411 .
9 is a displacement measurement in the process of focusing and focusing by measuring the main configuration of the linear type three-dimensional shape measuring device according to an embodiment of the present invention and the distance difference between the reference mirror and each optical path between the measurement object It is a diagram illustrating a path of light emitted from the light source 411 .
10 is a view showing the main configuration of a three-dimensional measuring device using an optical fiber type according to an embodiment of the present invention.

Hereinafter, a three-dimensional shape measuring apparatus for measuring a three-dimensional shape of an object to be measured according to the present invention is described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily practice the present invention. let me explain

In each drawing of the present invention, the size or dimensions of the structures are enlarged or reduced than the actual size for clarity of the present invention, and well-known components are omitted to reveal the characteristic configuration, so it is not limited to the drawings. .

In the detailed description of the principle of the preferred embodiment of the present invention, if it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, since the configuration shown in the embodiments and drawings described in this specification is only the most preferred embodiment of the present invention and does not represent all the technical spirit of the present invention, various It should be understood that there may be equivalents and variations.

3 to 5 are one embodiment of the three-dimensional shape measuring apparatus according to the present invention, based on these, the main configuration of the three-dimensional shape measuring apparatus according to the present invention will be described below.

3 is a diagram showing the configuration of a three-dimensional shape measuring apparatus according to an embodiment of the present invention. As shown in FIG. 3, the three-dimensional shape measuring apparatus according to the present invention includes a light source unit 100; a first optical splitter 200; reference mirror 300; photographing unit 500; and a displacement measurement value along an optical path between the light reflected from the first light splitter 200 reaching the reference mirror and the light reflected from the first light splitter 200 reaching the measurement object 600 and a displacement measurement unit 400 for measuring and focusing on the measurement object 600 to form an image, and the remaining parts except the displacement measurement unit 400 correspond to known components according to the prior art .

These will be described in more detail below. First, the light source unit 100 is a means for emitting light to the measurement object to measure the three-dimensional shape of the measurement object. The shape of the measurement surface can be measured, and as shown in FIG. 3 , it is located in one direction (left) of the light splitter, which is opposite to the reference mirror and may be located on the right or left side of the light splitter.

The light source of the light source unit 100 may use a white light source. The white light source is a light source for obtaining data on the three-dimensional shape of the object to be measured, and may be one such as a tungsten halogen lamp, a Xenon lamp, or a white light emitting diode, and the light source is a broadband white light can be

On the other hand, the first light splitter divides the light (light) irradiated (emitted) from the light source unit 100 so that a part is irradiated to the measurement object, and the remaining part is transmitted to go straight and irradiated toward the reference mirror 300 , respectively. A beam splitter for splitting, which may be selected from any one of a cubic type, a thin film type, and a plate type, but is not limited thereto.

Referring to FIG. 3 , the white light transmitted through the first light splitter 200 is irradiated to the reference mirror 300 , and the white light reflected from the first light splitter 200 is irradiated to the measurement object 600 . The transmitted white light functions as the reference light irradiated to the reference mirror 300 , and the white light reflected in the direction of the measurement object is irradiated to the measurement object and thus performs the function of the measurement light.

That is, the first light splitter 200 separates the light irradiated from the light source into reference light and measurement light, and when the separated reference light and measurement light are reflected and returned, they interfere to form interference light.

Meanwhile, a collimating lens (not shown) for transmitting the light of the light source to the beam splitter may be included between the first light splitter 200 and the light source.

On the other hand, the reference mirror 300 is located in the other direction of the first light splitter facing the light source unit, the divided light from the first light splitter 200 is irradiated and reflected back to the first light splitter function to That is, the reference mirror 300 corresponds to the turning point of the optical path where the white light passing through the first light splitter 200 is finally reflected and returns to the first light splitter, and in FIG. 3 , the first light splitter 200 . and an extension line of the light source unit.

Meanwhile, the first light splitter 200 in the three-dimensional shape measuring device may be horizontally or vertically moved between the light source unit 100 and the reference mirror 300 . More specifically, the three-dimensional shape measuring apparatus in the present invention fixes the reference mirror and drives the first light splitter 200 to move horizontally or vertically between the light source unit 100 and the reference mirror 300, so that the reference mirror It is also possible to make the reflection distance from and the reflection distance from the measurement object the same.

In addition, the reference mirror 300 in the three-dimensional shape measuring device may be horizontally movable in parallel with the optical path between the light source unit 100 and the first light splitter 200 , which is the first light splitter 200 . By fixing and driving the reference mirror, the reflection distance from the reference mirror and the reflection distance from the measurement object can be made the same.

Also, in the present invention, by driving both the first light splitter 200 and the reference mirror, the reflection distance in the reference mirror and the reflection distance in the measurement object may be the same.

That is, the light that has passed through the first light splitter 200 in FIG. 3 is irradiated to the reference mirror 300, and the light irradiated to the reference mirror is reflected again to reach the first light splitter, By moving the reference mirror 300 or the first light splitter in the horizontal direction or moving in the horizontal direction from the extension line connecting the light source unit and the reference mirror, the reflection distance of the light passing through the measurement object based on the first light splitter and the reference mirror By making the light reflection distance the same, information on the height of the surface of the measurement object can be obtained.

Meanwhile, the present invention may include respective moving means (not shown) for horizontally or vertically moving the reference mirror 300 or the first light splitter 200 in the three-dimensional shape measuring device.

On the other hand, since the distance to be adjusted between the first light splitter and the reference mirror is very fine, the first light splitter 200 or the reference mirror 300 must be able to be moved very finely, and in order to move them finely, the present invention of the three-dimensional shape measuring device can add a fine driving device (not shown) for their movement.

In addition, the micro-actuator used to adjust the position of the first light splitter 200 or the reference mirror 300 can simultaneously serve as a support for supporting the first light splitter 200 or the reference mirror. there is.

Here, the fine actuator may use a device capable of moving a distance in the range of several tens of mm (1 to 100 mm), for example, a piezoelectric actuator widely used for fine positioning may be used.

On the other hand, the photographing unit 500 is an interference fringe in which the light reflected by being irradiated to the surface of the measurement object and the light reflected by the reference mirror 300 and reflected along the optical path passing through the first light splitter are combined. A CCD or CMOS camera (charge-coupled device camera) may be used, but any device capable of measuring the shape of the measurement surface of the measurement object from the interference fringe may be used without limitation.

That is, the interference fringe formed by the light irradiated from the light source 100 is reflected from the reference mirror 300, the light entering through the first light splitter and the first light splitter 200 after being reflected from the measurement surface of the object to be measured. ), in order to obtain such an interference fringe, the distance from the first light splitter 200 to the surface of the measurement object and the distance from the first light splitter 200 to the reference mirror 300 must be matched. Accordingly, for a measurement target having a step difference, an interference fringe acquisition section is uniformly divided according to height information, the reference mirror 300 is fixed for each divided section, and the first beam splitter is precisely moved or While the first light splitter is fixed, the surface shape can be measured by obtaining an interference fringe while moving the reference mirror finely.

On the other hand, the displacement measuring unit 400 corresponding to the technical feature of the three-dimensional shape measuring device according to the present invention obtains the interference fringe as a pattern in which the light entering through the first light splitter 200 is combined to measure the three-dimensional shape. , the light reflected by reaching the reference mirror from the first light splitter 200 to focus on the measurement object, and the light reflected by reaching the measurement object 600 from the first light splitter 200 It serves to measure the displacement measurement value according to the optical path between the displacement measurement unit 400 emits a separate light independent of the light emitted from the light source unit 100, the reference to the measurement object (600) It includes a distributed displacement interferometer 410 for measuring displacement according to the optical path between the mirror and the measurement object, wherein the distributed displacement interferometer 410 is a component thereof, and separate light from the light emitted from the light source unit 100 is provided. Displacement measurement light source 411 to emit; and a dispersive interferometer spectrometer 413 that is emitted from the displacement measurement light source 411 and reaches each of the measurement object 600 and the reference mirror 300 and is reflected back to disperse the merged light, thereby measuring the interference information of the dispersed light. ); and the light emitted from the displacement measurement light source 411 in the distributed displacement interferometer 410 is irradiated to the measurement object and the reference mirror through the first light splitter 200, and then the first light again It is a feature of the present invention to arrive at the distributed interferometric spectrometer (413) via the divider (200).

That is, the three-dimensional shape measuring apparatus according to the present invention introduces the displacement measuring unit 400 including the distributed displacement interferometer 410 into the existing three-dimensional three-dimensional shape measuring interferometer, and thus the surface in the existing three-dimensional three-dimensional shape measuring interferometer. Prior to irradiation of the measurement light from the light source unit 100 for measuring the shape, the distance from the reference point (eg, beam splitter, reference mirror, etc.) in the interferometer to a specific position on the surface of the measurement object is first measured, and through this An optical system or a measurement system equipped with a reference mirror in a three-dimensional stereoscopic shape measurement interferometer of

Therefore, for this purpose, the displacement measurement unit 400 may include a displacement measurement light source 411 independent from the light source unit 100 in order to emit a separate light independent from the light emitted from the light source unit 100 . Thereby, the displacement along the optical path between the light reflected from the first light splitter 200 reaching the reference mirror and the light reflected from the first light splitter 200 reaching the measurement object 600 . A measurement value can be measured, wherein, when the light emitted from the displacement measurement light source is irradiated to the measurement object, the light irradiated to the measurement object must pass through the first light splitter 200 and irradiate the measurement object In addition, the light reflected from the measurement object must also return through the first light splitter 200, and the reflected light returning through the first light splitter 200 is focused by the distributed interferometer spectrometer 413. It is characterized in that the distance is measured.

On the other hand, the displacement measurement unit 400 divides the light emitted from the displacement measurement light source 411 in the distributed displacement interferometer 410 in the optical path between the light source unit 100 and the first light splitter 200. A second light splitter 420; further including, the light emitted from the displacement measurement light source 411 in the distributed displacement interferometer 410 passes through the first light splitter 200 to reach the measurement object and the reference mirror, and then again It can be reflected to reach the distributed interferometer spectrometer 413 in the distributed displacement interferometer 410 through the first optical splitter 200 .

At this time, between the displacement measurement light source 411 and the second light splitter 420 in the distributed displacement interferometer 410, the light is emitted from the displacement measurement light source 411 to reach the measurement object and then reflected to the first beam splitter and A dispersion-displacement interferometer optical splitter 412 for splitting the reflected light returning through the second optical splitter into the dispersion-type interferometric spectrometer 413 in the dispersion-displacement interferometer 410 may be additionally included.

This can be explained through Fig. 4, which shows the main configuration of the distributed displacement interferometer 410 in the three-dimensional shape measuring apparatus according to an embodiment of the present invention, and between the light source unit and the second light splitter 420. As a diagram illustrating a coupling relationship, as shown in FIG. 4 , an optical path between the light source unit 100 and the first light splitter (not shown in FIG. 4 , located on the right side of the second light splitter 420 ) A second beam splitter 420 is provided, and the reflected light traveling from the first splitter toward the second splitter is partially emitted in the vertical direction by the second splitter, and thus toward the distributed displacement interferometer 410. will proceed

In this case, the distributed displacement interferometer 410 may additionally include a light splitter 412 in the distributed displacement interferometer between the displacement measurement light source 411 and the second optical splitter 420, whereby the displacement measurement light source 411 When the light emitted from ) is reflected back through the measurement object and the reference mirror, a part of the light splitter 412 in the distributed displacement interferometer is reflected toward the distributed interferometer spectrometer 413, so that the distributed interferometer 413 ) can measure a displacement measurement value according to an optical path between the light reflected by reaching the reference mirror and the light reflected by reaching the measurement object 600 from the first light splitter 200 .

In addition, the displacement measuring light source 411 according to the present invention is located in a direction perpendicular to the optical path between the light source unit 100 and the first light splitter 200 and is independent of the light emitted from the light source unit 100 . may be configured to emit in the direction of the second light splitter 420 .

According to the above configuration, the light (light) reflected from the second optical splitter through the first optical splitter is emitted in the vertical direction where the dispersion displacement interferometer 410 is located, and the optical splitter 412 in the dispersion displacement interferometer 412 The dispersion interferometer in the displacement measuring unit 400 including the distributed displacement interferometer 410 according to the present invention is incident to the scattering interferometer 413, which is incident on the The distance from the first light splitter 200 to the surface of the measurement object can be measured by the spectrometer 413 , and a process for forming an image by focusing thereafter can be performed.

The measurement principle of the distributed interferometer applied at this time is as follows.

If the distance from the reflective coating layer of the first light splitter to the surface of the measurement object is L1 and the distance to the reference mirror is L2, the interference signal due to the distance difference L (= L2-L1) measured by the spectrometer is [Equation 1] is expressed.

[Equation 1]

Here, k is the wave number, C ₀ is the light flux in vacuum, n is the refractive index of the medium, is the optical frequency, a(υ) is the mean optical intensity of the measured signal in the optical frequency domain, and b(υ) is the modulation amplitude of the interference signal, which is the frequency of the light source. It has a relationship between the distribution s(υ) and [Equation 2].

[Equation 2]

Here, r _r (υ) and r _m (υ) are reflection coefficients according to the frequency of the measurement surface, which are characteristics that change slowly, and can be assumed to be 1. Accordingly, the measurement light and the interference signal generated by the measurement light are summarized in [Equation 3].

[Equation 3]

As in [Equation 3], the interference signal for each channel shows a light intensity distribution showing the frequency characteristic of the light source, and at the same time, represents a signal changed by the phase φ(υ) of the interference signal. Therefore, the distance L for measurement is included in the phase φ(υ) of the interference signal, and φ(υ) according to the frequency is expressed by [Equation 4].

[Equation 4]

Here, as methods of extracting φ(υ), there are a method using synchronous sampling, a method of performing a Fourier transform to detect a peak, and the like, and in the present invention, a Fourier transform is applied and described, When [Equation 3] is expressed in the form of a complex number in order to apply the Fourier transform, it becomes [Equation 5].

[Equation 5]

Next, if [Equation 5] is Fourier transformed, it becomes [Equation 6].

[Equation 6]

Here, S (τ) is a Fourier transform function of s(υ), δ(τ) is a Dirac-delta function, and α is a substitution variable of _{2nL/c 0 as in [Equation 4].} . Since α can be directly measured from the positions of the peaks (peaks), the distance difference L can be measured using [Equation 4].

On the other hand, the second light splitter 420 in the present invention is not located in the optical path between the light source unit 100 and the first light splitter 200 as described above, and as shown in FIG. 5 , the photographing unit ( 500) and the first optical splitter 200 may be provided in the optical path.

5 is a diagram showing the configuration of a three-dimensional shape measuring apparatus according to another embodiment of the present invention. As shown in FIG. 5, the displacement measuring unit 400 in the three-dimensional shape measuring apparatus according to the present invention. is a second optical splitter 420 for splitting the light emitted from the displacement measuring light source 411 in the distributed displacement interferometer 410 in the optical path between the photographing unit 500 and the first optical splitter 200; It may additionally include, and through this, the light emitted from the displacement measurement light source 411 in the distributed displacement interferometer 410 reaches the measurement object and the reference mirror through the first light splitter 200 and is reflected back to the first The light reflected by reaching the reference mirror by reaching the distributed interferometer spectrometer 413 in the distributed displacement interferometer 410 through the optical splitter 200, and the measurement object ( 600) to measure a displacement measurement according to the optical path between the reflected light.

In this case as well, as before, between the displacement measuring light source 411 and the second optical splitter 420 in the distributed displacement interferometer 410, the reflected light returning through the first and second optical splitters is transmitted through the distributed displacement interferometer. It may additionally include a light splitter 412 in a distributed displacement interferometer that divides it into a dispersed interferometer spectrometer 413 in 410, and the displacement measurement light source 411 in the distributed displacement interferometer 410 is the photographing unit Located in a direction perpendicular to the optical path between 500 and the first light splitter 200, a separate light independent from the light emitted from the light source unit 100 can be emitted in the direction of the second light splitter 420. there is.

On the other hand, the displacement measuring light source 411 according to the present invention may use a white light source or a monochromatic light like the light source unit 100. In this case, as a light source for using the monochromatic light, a laser light emitting diode, etc. may be used. can

In addition, in the present invention, the dispersive interferometer spectrometer 413 is emitted from the displacement measuring light source 411, reaches the measurement object, and then is reflected to the first light splitter, the second light splitter and the dispersed displacement interferometer light splitter ( It may include a dispersion displacement spectrometer 415 for dispersing the reflected light passing through 412 and a dispersion displacement optical measurement device 414 for measuring the light dispersed from the spectrometer. ) shows a configuration including a dispersion displacement spectrometer 415 and a dispersion displacement optical measuring device 414 .

6 shows the main configuration of the distributed interferometer spectrometer 413 in the three-dimensional measuring device according to an embodiment of the present invention, and measuring the distance difference along each optical path between the reference mirror and the measurement object to focus and form an image. As a diagram showing the path of the light emitted from the displacement measuring light source 411 in the process, the distributed interferometer uses the principle of combining optical interference and spectroscopy. As shown in FIG. 6, the second optical splitter 420 It includes a spectroscopic device 415 for dispersing the light reflected from the spectroscopic device and a dispersion displacement optical measuring device 414 for measuring the light dispersed from the spectroscopic device, wherein the light emitted from the displacement measuring light source 411 is divided into a second beam splitter. After passing through 420 and the first optical splitter 200, it is reflected from the reference mirror and the measurement object, respectively, is incident on the distributed displacement interferometer 410, is reflected by the optical splitter 412 in the distributed displacement interferometer, and the spectroscopic element 415 ) to each wavelength, and arrives at the dispersion displacement optical measuring device 414 to obtain an interference signal.

Hereinafter, a method of measuring the distance of a measurement object in a three-dimensional measuring device having a distributed displacement interferometer 410 according to the present invention will be described in its entirety with reference to FIG. 6 .

As described above in FIG. 6 , it includes a distributed interferometer spectrometer 413 and a distributed displacement interferometer optical splitter 412 , and the displacement measurement light source 411 is located between the light source unit 100 and the first optical splitter 200 . Located in the direction perpendicular to the optical path, a separate light is emitted in the direction of the second light splitter 420 , thereby reaching the reference mirror and reflected light, and the measurement object 600 from the first light splitter 200 . ), the path of the light emitted from the displacement measuring light source 411 is shown in the process of measuring the displacement measurement value according to the optical path between the reflected light.

As shown in FIG. 6, first, other components except for the displacement measuring unit 400 in the three-dimensional shape measuring device are not operated or at least fixed so that they do not move, and then in the displacement measuring light source 411 such as a laser diode. When light is irradiated to focus on the measurement object, it passes through the light splitter 412 in the dispersion displacement interferometer and is reflected by the second light splitter 420, and then the light is split and reflected by the first light splitter 200 The light to be measured proceeds to the measurement object, and the light passing through proceeds to the reference mirror, and the light reflected from the measurement object and the light reflected from the reference mirror pass through or reflect the first light splitter 200 again to the second After being reflected by the optical splitter 420, it is reflected again by the optical splitter 412 in the distributed displacement interferometer, and through the distributed interferometric spectrometer 413; It is possible to measure the distance to the measurement object through calculation by one shot.

Meanwhile, FIG. 7 is another embodiment of the present invention, and has the configuration of FIG. 5 in which the second optical splitter 420 is provided in the optical path between the photographing unit 500 and the first optical splitter 200 . The main configuration of the distributed interferometer spectrometer 413 in this case and the distance difference according to each optical path between the reference mirror and the measurement object is measured and focused and the light emitted from the displacement measuring light source 411 is It corresponds to a drawing showing a path, and the contents of its operation and measurement can be easily understood from FIG. 6 .

In addition, the three-dimensional shape measuring apparatus according to the present invention can measure displacement (distance difference) for a specific part with only one shot data without mechanical driving for a specific point of the measurement object. If it corresponds to a three-dimensional stereoscopic shape measuring device that can be equipped with a distributed interferometer, it can be used without limitation in type, and for example, types such as Michelson, Mirau, Linnik, and Pizo can be used, preferably Any one selected from Michelson, Mirau, or Linnik type may be used.

For example, FIG. 6 shows a Michelson-type three-dimensional shape measuring device, and FIG. 8 measures the main configuration of the Mirau-type three-dimensional shape measuring device and the distance difference according to each optical path between the reference mirror and the measurement object. The path of the light emitted from the displacement measurement light source 411 is shown in the process of focusing and forming an image. In the case of the mirror type, an additional light splitter is provided between the measurement object and the first light splitter, but the reference mirror is It is provided between the light splitter and the first light splitter.

On the other hand, in FIG. 9, in the process of focusing and forming an image by measuring the distance difference according to the main configuration and each optical path between the reference mirror and the measurement object in the linear type three-dimensional measuring device, emission from the displacement measuring light source 411 In the case of the linear type, an objective lens may be provided between the first light splitter and the reference mirror and between the first light splitter and the measurement object.

Meanwhile, at least a part of the distributed displacement interferometer 410 in the present invention may be configured in an optical fiber method, which will be described with reference to FIG. 10 .

10 is a view showing the main configuration of a three-dimensional measuring device using an optical fiber type according to an embodiment of the present invention. As shown in FIG. 10, as a displacement measuring light source 411, SLD (Super-Luminescent) Diode) can be used to emit light to the second beam splitter through an optical coupler within a single mode fiber, and after reaching the reference mirror and the measurement object, it is reflected and reflected to the first light The light (light) combined through the splitter and the second splitter is the light reflected by reaching the reference mirror from the distributed displacement spectrometer (DG) and the distributed displacement photometric device (PDA) in the optocoupler, and the first splitter ( 200), it is possible to measure the displacement measurement value according to the optical path between the light reaching the measurement object 600 and reflected.

On the other hand, the optical path between the light reflected by reaching the reference mirror in the three-dimensional measuring device including the reference mirror according to the present invention and the light reflected by reaching the measurement object 600 from the first light splitter 200 . The process of measuring the displacement measurement value according to By measuring the displacement measurement value through the spectrometer 413, information on the distance difference according to the optical path is obtained, and the measurement object 600 is independently moved by the distance difference (displacement difference) according to the information obtained in this way, or , or after fixing the measurement object 600 and independently moving at least a portion of the three-dimensional shape measuring device including at least one of the light source unit 100, the first light splitter 200, and the reference mirror 300, the By scanning the reference mirror or the first beam splitter, a three-dimensional shape may be obtained by the photographing unit.

To this end, in the three-dimensional shape measuring apparatus according to the present invention, the light emitted from the displacement measuring light source 411 from the displacement measurement value obtained by the displacement measuring unit 400 is transmitted from the first light splitter 200 as a reference mirror. In order to match the respective distances along the optical path between the light that arrives and is reflected and the light that reaches and reflects from the first light splitter 200 to the measurement object 600, the measurement object 600 is independently measured. or independently moving at least a portion of the three-dimensional shape measuring device including at least one of the light source unit 100 , the first light splitter 200 , and the reference mirror 300 while fixing the measurement object 600 . may additionally include; in this case, the control unit 700 may be configured to additionally move the position of the first light splitter 200 or the reference mirror 300 .

The present invention also provides a method for measuring a three-dimensional shape of an object to be measured using the three-dimensional shape measuring device.

To explain this in more detail according to specific steps, first, as described above, after fixing other components except for the displacement measuring unit 400 in the three-dimensional shape measuring device to not operate or at least not to move, the laser diode Light is irradiated to the measurement object in order to measure the displacement measurement value according to the optical path between the reference mirror and the measurement object 600 from the first light splitter 200 in the displacement measurement light source 411, such as The light reflected from the object and the light reflected from the reference mirror are combined and proceed to the distributed interferometer spectrometer 413, through which the displacement measurement value (from the first light splitter 200 to the reference mirror and the measurement object 600) (distance difference according to the optical path) is measured through calculation by one shot without mechanical driving.

As a subsequent process, according to the optical path between the light reflected from the first light splitter 200 reaching the reference mirror and the light reflected from the first light splitter 200 reaching the measurement object 600 . In order to match each distance, the measurement object 600 is independently moved by the distance difference, or the measurement object 600 is fixed and the light source unit 100, the first light splitter 200 and the reference mirror ( 300) to independently transfer at least a portion of the three-dimensional shape measuring device including at least one to maintain an optimal distance for measuring the three-dimensional three-dimensional shape of the object to be measured in the remaining three-dimensional measuring devices except for the displacement measuring unit 400 The light source unit 100 according to the present invention emits light for measuring a three-dimensional shape and scans any one of the reference mirror, the measurement object, and the entire measurement system in the optical axis direction to measure the three-dimensional shape. .

On the other hand, the light reflected by reaching the reference mirror from the first light splitter 200 made by the displacement measuring unit 400, and the first light splitter 200 reaching the measurement object 600 and being reflected The measurement method of the three-dimensional shape remaining except for the step of focusing and forming an image by matching each distance along the optical path between the lights may proceed according to a conventionally known method, illustratively using the method described below Can be used.

In general, the interference fringe formed by the light irradiated from the light source unit 100 is reflected by the reference mirror 300, the light entering through the first light splitter and the first light splitter 200 after being reflected from the measurement surface of the object to be measured. In order to obtain such an interference fringe as a pattern in which the light entering through Accordingly, for a measurement target having a step difference, an interference fringe acquisition section is uniformly divided according to height information, and then the reference mirror 300 or the first beam splitter is precisely moved for each divided section to obtain an interference fringe. Measure the surface shape.

Here, the three-dimensional shape measuring apparatus according to the present invention can additionally control the position of at least one of the measurement object 600, the first light splitter 200, and the reference mirror 300, in this case, the control unit is the measurement object, Alternatively, the first beam splitter 200 or the reference mirror 300 may be independently controlled, and they may be simultaneously controlled to drive each at the same time, and additionally, the image captured through the photographing unit 500 may be processed. It can be configured to play an integrated role.

That is, the control unit can control the movement of the reference mirror 300 when the first optical splitter 200 is fixed, and vice versa, when the reference mirror 300 is fixed, the first optical splitter ( 200) can be controlled, and when the positions of the first light splitter 200 and the reference mirror 300 are adjusted at the same time, they can be individually controlled at the same time.

On the other hand, an imaging lens 501 for condensing the reflected light to the photographing unit may be included between the first light splitter and the photographing unit 500 , and also between the first light splitter 200 and the reference mirror 400 . A polarizer may be additionally included. The polarizer used at this time may be a linear polarizer, and linearly polarizes the reference light so that the reference light has only a polarization component in one direction.

As the polarizer is included, a compensating plate may be additionally included on the optical path of the measurement light, and the compensating plate may compensate for a phase difference with the measurement caused by the reference light passing through the linear polarizer.

As described above, the present invention has been described with reference to the embodiment shown in the drawings, but this is merely exemplary, and various modifications and equivalent other embodiments are possible therefrom by those of ordinary skill in the art. will understand the point. Therefore, the technical protection scope of the present invention should be defined by the following claims.

100: light source unit
200: first optical splitter
300: reference mirror
400: displacement measuring unit
410: distributed displacement interferometer
411: displacement measurement light source (laser diode)
412: optical splitter in distributed displacement interferometer
413 Dispersive Interferometric Spectrometer
414: Distributed displacement optical measuring device (CCD)
415: spectroscopy element
420: second splitter
500: shooting department
501: image forming lens
600: measurement object

Claims (14)

a light source unit 100 emitting light and positioned in one direction of the first light splitter 200;
a first light splitter 200 for splitting the light from the light source unit 100 into a measurement object 600 and a reference mirror 300 below;
a reference mirror 300 located in the other direction of the first light splitter opposite to the light source unit, the divided light from the first light splitter 200 is irradiated and reflected back to the first light splitter;
Taking pictures of an interference fringe in which the light irradiated from the light source unit 100 to the surface of the object to be measured and reflected, and the light reflected from the reference mirror 300 and light along the optical path passing through the first light splitter 200 are combined part 500; and
A separate light independent of the light emitted from the light source unit 100 is emitted, thereby reaching the reference mirror from the first light splitter 200 and reflected light and the first light splitter 200 from the measurement object A three-dimensional shape measuring device comprising a; a displacement measuring unit 400 for measuring a displacement measurement value according to an optical path between light reaching and reflected (600),
The displacement measuring unit 400 includes a displacement measuring light source 411 for emitting a separate light independent of the light emitted from the light source unit 100; and a dispersive interferometer spectrometer 413 that is emitted from the displacement measurement light source 411 and reaches each of the measurement object 600 and the reference mirror 300 and is reflected back to disperse the merged light, thereby measuring the interference information of the dispersed light. ); Distributed displacement interferometer 410, including;
The light emitted from the displacement measurement light source 411 in the distributed displacement interferometer 410 is irradiated to the measurement object and the reference mirror through the first light splitter 200, and then passes through the first light splitter 200 again. A stereoscopic shape measuring device, characterized in that it reaches a distributed interferometric spectrometer (413).
According to claim 1,
The first light splitter (200) is a three-dimensional shape measuring apparatus, characterized in that horizontal or vertical movement between the light source unit (100) and the reference mirror (300).
According to claim 1,
The reference mirror 300 is a three-dimensional shape measuring device, characterized in that it is possible to move horizontally in parallel with the optical path between the light source unit 100 and the first light splitter (200).
According to claim 1,
The displacement measurement unit 400 divides the light emitted from the displacement measurement light source 411 in the distributed displacement interferometer 410 in an optical path between the light source unit 100 and the first light splitter 200. A second light Divider 420; Including additionally,
The light emitted from the displacement measurement light source 411 in the dispersion displacement interferometer 410 passes through the first optical splitter 200 to reach the measurement object and the reference mirror, is reflected again, and passes through the first optical splitter 200 to disperse the light. A three-dimensional shape measuring apparatus, characterized in that it can reach the dispersive interferometer spectrometer (413) in the displacement interferometer (410).
According to claim 1,
The displacement measurement unit 400 divides the light emitted from the displacement measurement light source 411 in the distributed displacement interferometer 410 in an optical path between the photographing unit 500 and the first optical splitter 200. Light splitter 420; Including additionally,
The light emitted from the displacement measurement light source 411 in the dispersion displacement interferometer 410 passes through the first optical splitter 200 to reach the measurement object and the reference mirror, is reflected again, and passes through the first optical splitter 200 to disperse the light. A three-dimensional shape measuring apparatus, characterized in that it can reach the dispersive interferometer spectrometer (413) in the displacement interferometer (410).
6. The method according to claim 4 or 5,
Between the displacement measurement light source 411 and the second light splitter 420 in the dispersion displacement interferometer 410, the light is emitted from the displacement measurement light source 411 and is reflected after reaching the measurement object to be reflected by the first beam splitter and the second beam splitter and a light splitter (412) in the dispersed displacement interferometer that divides the reflected light returning through the splitter into the dispersed interferometer spectrometer (413) in the dispersed displacement interferometer (410).
5. The method of claim 4,
The displacement measuring light source 411 in the distributed displacement interferometer 410 is located in a direction perpendicular to the optical path between the light source unit 100 and the first light splitter 200 and is independent of the light emitted from the light source unit 100 . A three-dimensional shape measuring device, characterized in that the light is emitted in the direction of the second light splitter (420).
6. The method of claim 5,
The displacement measuring light source 411 in the distributed displacement interferometer 410 is located in a direction perpendicular to the optical path between the photographing unit 500 and the first light splitter 200 and is independent of the light emitted from the light source unit 100 . A three-dimensional shape measuring device, characterized in that a separate light is emitted in the direction of the second light splitter (420).
7. The method of claim 6,
The dispersive interferometer spectrometer 413 emits from the displacement measurement light source 411, reaches the measurement object, is reflected, and passes through the first light splitter, the second light splitter and the dispersed displacement interferometer light splitter 412. A three-dimensional shape measuring apparatus comprising: a distributed displacement spectroscopic device (415) for dispersing; and a distributed displacement optical measurement device (414) for measuring the light dispersed from the spectroscopic device.
According to claim 1,
The three-dimensional shape measuring device is a three-dimensional shape measuring device, characterized in that any one selected from Michelson, Mirau, and Linnik type.
According to claim 1,
The distributed displacement interferometer 410 is a three-dimensional shape measuring device, characterized in that at least part of the optical fiber method.
According to claim 1,
In the three-dimensional shape measuring device, from the displacement measurement value obtained by the displacement measurement unit 400 , the light emitted from the displacement measurement light source 411 reaches the reference mirror from the first light splitter 200 and is reflected. , to independently move the measurement object 600 to match each distance along the optical path between the light reaching and reflected from the first light splitter 200, or the measurement A control unit 700 capable of fixing an object 600 and independently moving at least a portion of a three-dimensional shape measuring device including at least one of the light source unit 100, the first light splitter 200, and the reference mirror 300 ; A three-dimensional shape measuring device, characterized in that it further comprises.
13. The method of claim 12,
The control unit 700 is a three-dimensional shape measuring device, characterized in that it can additionally move the position of the first light splitter 200 or the reference mirror (300).
A method for measuring a three-dimensional shape of an object to be measured using the three-dimensional shape measuring device according to any one of claims 1 to 5, 7, 8, and 10 to 13.

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