JP2014106094A - Shape measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape measurement device which can measure the shape of an object to be measured with high precision and whose cost can be reduced.SOLUTION: A light projection part 110A includes a pattern generation part 112 and a both-side telecentric optical system TT. The pattern generation part 112 generates measurement luminous flux having a pattern for shape measurement. The both-side telecentric optical system TT guides the generated measurement luminous flux to an upper surface of a stage 140 from oblique upper part of the stage 140. A light reception part receives reflected luminous flux traveling to the upper part of the stage 140 from the object to be measured placed on the stage 140 and outputs a reception signal indicating a light reception amount. The stage 140, pattern generation part 112, and the both-side telecentric optical system TT of the light projection part 110A are arranged so that a light emission plane of the pattern generation part 112 and the upper surface of the stage 140 accord with Scheimpflug principle with respect to a main plane of the both-side telecentric optical system TT.

Description

  The present invention relates to a shape measuring apparatus.

  In the shape measuring apparatus of the triangulation system, a pixel in which light is irradiated on the surface of the measurement object while the measurement object is placed on the upper surface of the stage, and the reflected light is arranged one-dimensionally or two-dimensionally. It is received by a light receiving element having The height of the surface of the measurement object can be measured based on the peak position of the received light amount distribution obtained by the light receiving element. Thereby, the shape of the measurement object can be measured.

  Non-Patent Document 1 proposes a shape measurement by a triangulation system that combines encoded light and a phase shift method. Further, Non-Patent Document 2 proposes a shape measurement using a triangulation system in which encoded light and striped light are combined. In these methods, the accuracy of the shape measurement of the measurement object can be improved.

Toni F. Schenk, "Remote Sensing and Reconstruction for Three-Dimensional Objects and Scenes", Proceedings of SPIE, Volume 2572, pp. 1-9 (1995) Sabry F. El-Hakim and Armin Gruen, "Videometrics and Optical Methods for 3D Shape Measurement", Proceedings of SPIE, Volume 4309, pp. 219-231 (2001)

  Light irradiated on the measurement object (hereinafter referred to as measurement light beam) has a predetermined pattern, and can be generated by reflecting light generated by a light source with a DMD (digital micromirror device). . The DMD includes a plurality of micromirrors that respectively configure a plurality of pixels arranged two-dimensionally. The pattern of the measurement light beam is adjusted by controlling each of the plurality of pixels of the DMD.

  For example, a measurement light beam having a rectangular cross section is irradiated obliquely from above toward the upper surface of the stage. At this time, the irradiation region of the measurement light beam on the upper surface of the stage may have a trapezoidal shape instead of a rectangular shape. Thus, when the irradiation region of the measurement light beam on the upper surface of the stage has a completely different shape from the cross-sectional shape of the measurement light beam generated by the DMD, the shape of the measurement object cannot be measured accurately. .

  In view of this, it is conceivable to perform shape measurement by the triangulation method by correcting the light reception data obtained when the light receiving element receives the reflected light from the measurement object. However, at the time of this correction, it is necessary to calculate at which position on the light receiving surface of the light receiving element the light beams respectively emitted from the plurality of pixels of the DMD are incident. If the relationship between the emission position of the light beam in the DMD and the light reception position of the light beam in the light receiving element is different for each DMD pixel, it is necessary to perform a number of different arithmetic processes. Therefore, time is required for complicated arithmetic processing, and the measurement time becomes long. In order to shorten the arithmetic processing time, an expensive processing device having high performance is required. In this case, the cost of the shape measuring apparatus increases.

  An object of the present invention is to provide a shape measuring apparatus that can measure the shape of an object to be measured in a short time with high accuracy and can realize cost reduction.

  (1) A shape measuring apparatus according to the present invention is a shape measuring apparatus that irradiates a measurement light beam to a measurement object and measures a three-dimensional shape of the measurement object by a triangulation method based on a reflected light beam from the measurement object. A stage having an upper surface on which the measurement object is placed, a first light projecting device that projects a measurement light beam obliquely from above toward the upper surface of the stage, and a measurement object placed on the stage. A light receiving device configured to receive a light beam reflected above the stage and output a light reception signal indicating the amount of light received, the first light projecting device includes a first light source that generates light, A first pattern generation unit that generates and emits light having a pattern for shape measurement as a measurement light beam from light generated by the first light source, and a measurement light beam emitted by the first pattern generation unit 1st leading to the top The stage, the first pattern generation unit, and the first double-sided telecentric optical system include a first telecentric optical system in which the exit surface of the first pattern generation unit and the upper surface of the stage are the main ones of the first double-side telecentric optical system. It is arranged to follow the Scheinproof principle with respect to the plane.

  In the shape measuring apparatus, light is generated by a first light source, and light having a pattern for shape measurement is generated as a measurement light beam by a first pattern generation unit. The generated measurement light beam is emitted from the emission surface of the first pattern generation unit. The emitted measurement light beam is irradiated from the obliquely upper side of the stage toward the upper surface of the stage through the first both-side telecentric optical system. Thereby, the measurement light beam is irradiated to the measurement object placed on the upper surface of the stage.

  A reflected light beam traveling upward from the measurement object placed on the stage is received by the light receiving device. As a result, a light receiving signal indicating the amount of light received is output from the light receiving device. Based on the received light signal, the three-dimensional shape of the measurement object is measured by the triangulation method.

  Since the exit surface of the first pattern generation unit and the upper surface of the stage follow the Scheinproof principle with respect to the main plane of the first double-sided telecentric optical system, the entire output surface of the first pattern generation unit is formed on the upper surface of the stage. Can be focused.

  Further, a measurement light beam (hereinafter referred to as an outgoing light beam) emitted from the emission surface of the first pattern generation unit to the first both-side telecentric optical system and the upper surface of the stage are irradiated from the first both-side telecentric optical system. Each measurement light beam (hereinafter referred to as an irradiation light beam) is a parallel light beam. Therefore, the cross-sectional size and shape of the outgoing light beam are constant at an arbitrary position in the traveling direction, and are equal to the cross-sectional size and shape of the measurement light beam on the outgoing surface of the first pattern generation unit. Further, the size and shape of the cross section of the irradiated light beam are constant at an arbitrary position in the traveling direction. The cross-sectional shape of the irradiated light beam is similar to the cross-sectional shape of the emitted light beam. Since the size and shape of the cross section of the irradiated light beam are constant at an arbitrary position, the size and shape of the irradiation region of the irradiated light beam on the measurement object are different even when the height of the measurement object on the stage is different. Will be equal. As a result, when measuring a measurement object having a plurality of portions having different heights, it is possible to suppress variations in the accuracy of the measurement results of the plurality of portions.

  The irradiation light beam is a light beam whose chief ray is parallel to the optical axis. Therefore, when the irradiation light beam has a divergence angle, the cross section of the irradiation light beam becomes larger as the light travels in the traveling direction. Even in such a case, when the spread angle of the irradiation light beam is within a predetermined range, the cross section of the irradiation light beam is substantially constant in the traveling direction. Therefore, the irradiation light beam can be regarded as a parallel light beam.

  Here, a direction including the central axis of the irradiation light beam of the first light projecting device and parallel to the intersecting line of the surface perpendicular to the upper surface of the stage and the upper surface of the stage is referred to as a first direction. A direction perpendicular to and parallel to the upper surface of the stage is referred to as a second direction. Since the irradiation light beam is irradiated obliquely on the upper surface of the stage, the irradiation region of the irradiation light beam on the upper surface of the stage is expanded in the first direction with respect to the cross section of the irradiation light beam, and is expanded in the second direction. Not.

  In this case, the irradiation area is enlarged at the same ratio in the first direction with respect to the cross section of the irradiation light beam at an arbitrary position in the second direction. The size and shape of the cross section of the reflected light beam traveling from the upper surface of the stage toward the first light receiving device is constant at an arbitrary position in the traveling direction.

  As described above, the cross section of the reflected light beam toward the light receiving device is enlarged at a certain ratio in the first direction at an arbitrary position in the second direction with respect to the cross section of the emitted light beam, and is at an arbitrary position in the first direction. In the second direction, it is enlarged at a constant ratio. Therefore, it is possible to easily calculate at which position of the light receiving surface of the light receiving device the light beam emitted from any position on the output surface of the first pattern generation unit is incident. Thereby, the same arithmetic expression can be used for any position on the light receiving surface of the light receiving device. As a result, the calculation processing for the shape measurement of the triangulation method is simplified and the measurement time can be shortened. In addition, since it is not necessary to use an expensive processing apparatus having high performance, the cost of the shape measuring apparatus can be reduced.

  (2) In the first plane including the optical axis of the first light projecting device from the first light projecting device toward the upper surface of the stage and the optical axis of the light receiving device from the upper surface of the stage toward the light receiving device, The length of the irradiation region of the measurement light beam on the upper surface may be larger than the width of the reflected light beam that can be received by the light receiving device.

  Since the irradiation light beam is irradiated on the upper surface of the stage obliquely from above, the cross-sectional area of the reflected light beam that can be received by the light receiving device (hereinafter referred to as the light receiving area) and the irradiation region of the irradiation light beam on the upper surface of the stage If they are equal, the portion of the measurement object far from the first light projecting device may not be irradiated with the irradiation light beam. In that case, the portion of the measurement object that is not irradiated with the measurement light beam is a portion that cannot be measured.

  According to the above configuration, the length of the irradiation region of the measurement light beam on the upper surface of the stage is larger than the width of the reflected light beam that can be received by the light receiving device in the first surface. When measuring the shape of the object, it is possible to reduce the occurrence of non-measurable parts in the measurement object compared to the case where the irradiation area of the measurement light beam on the upper surface of the stage coincides with the light receiving area. .

  (3) The angle formed by the optical axis of the first light projecting device from the first light projecting device toward the upper surface of the stage and the axis orthogonal to the upper surface of the stage is represented by α, and the first The width of the measurement light beam guided from the light projecting device to the upper surface of the stage is represented by wp, the width of the reflected light beam that can be received by the light receiving device in the first surface is represented by wi, and can be measured in the optical axis direction of the light receiving device. When the size of the range is represented by 2 · v, the relationship of wp ≧ wi · cos α + 2 · v · sin α may be satisfied.

  In this case, by placing the measurement object on the light receivable region, the irradiation light beam from the first light projecting device over the entire measurement object within the measurable range in the optical axis direction of the light receiving device. Can be irradiated. Therefore, it is possible to further reduce the occurrence of a portion that cannot be measured.

  (4) The light receiving device includes a first light receiving element and a first light receiving optical system that guides the reflected light beam from the measurement object placed on the stage to the first light receiving element. The system may be an object side telecentric optical system or a double side telecentric optical system.

  In this case, the size and shape of the cross-section of the reflected light beam directed toward the object-side telecentric optical system or both-side telecentric optical system are constant at an arbitrary position in the traveling direction. Therefore, even when the height of the measurement object on the stage is different, the size and shape of the reflection region on the measurement object are equal. As a result, when measuring a measurement object having a plurality of portions having different heights, it is possible to suppress variations in the accuracy of the measurement results of the plurality of portions.

  (5) The range of the focal depth on the stage of the first both-side telecentric optical system of the first light projecting device may be larger than the range of the depth of field of the first light receiving optical system of the light receiving device.

  In this case, the range in which the measurement light beam can be irradiated with a certain degree of accuracy in the optical axis direction of the first double-sided telecentric optical system can receive the reflected light beam with a certain degree of accuracy in the optical axis direction of the first light receiving optical system. It becomes larger than the range. Accordingly, the height of the measurement object that can be measured with a certain level of accuracy during the shape measurement by the triangulation method can be determined based on the measurable range in the optical axis direction of the light receiving device.

  (6) The light receiving device includes a second light receiving element and a second light receiving optical system that guides the reflected light beam from the measurement object placed on the stage to the second light receiving element. The optical system is an object-side telecentric optical system or a double-sided telecentric optical system, and the magnification of the first light receiving optical system and the magnification of the second light receiving optical system may be different from each other. This makes it possible to observe the measurement object at a plurality of different magnifications.

  (7) The apparatus further includes a second light projecting device that projects the measurement light beam obliquely from above toward the upper surface of the stage. The second light projecting device includes a second light source that generates light and a second light source. A second pattern generation unit that generates and emits a light having a pattern for shape measurement as a measurement light beam from the light generated by the first step, and a second pattern generation unit that guides the measurement light beam emitted by the second pattern generation unit to the upper surface of the stage. The two-side telecentric optical system, and the stage, the second pattern generation unit, and the second double-side telecentric optical system are configured such that the exit surface of the second pattern generation unit and the upper surface of the stage are the second both-side telecentric optical system. It may be arranged to follow the Scheinproof principle with respect to the main plane of the.

  In this case, in the second projector, light is generated by the second light source, and light having a pattern for shape measurement is generated as a measurement light beam by the second pattern generation unit. The generated measurement light beam is emitted from the emission surface of the second pattern generation unit. The emitted measurement light beam is irradiated from the obliquely upper side of the stage toward the upper surface of the stage through the second both-side telecentric optical system. Thereby, the measurement light beam is irradiated to the measurement object placed on the upper surface of the stage.

  A reflected light beam traveling upward from the measurement object placed on the stage is received by the light receiving device. As a result, a light receiving signal indicating the amount of light received is output from the light receiving device. Based on the received light signal, the three-dimensional shape of the measurement object is measured by the triangulation method.

  Since the emission surface of the second pattern generation unit and the upper surface of the stage follow the Scheinproof principle with respect to the main plane of the second double-sided telecentric optical system, the entire emission surface of the second pattern generation unit is formed on the upper surface of the stage. Can be focused.

  Further, the outgoing light beam emitted from the emission surface of the second pattern generation unit to the second both-side telecentric optical system and the irradiation light beam emitted from the second both-side telecentric optical system onto the upper surface of the stage are parallel light beams, respectively. Therefore, the cross-sectional size and shape of the outgoing light beam are constant at an arbitrary position in the traveling direction, and are equal to the cross-sectional size and shape of the measurement light beam on the outgoing surface of the second pattern generation unit. Further, the size and shape of the cross section of the irradiated light beam are constant at an arbitrary position in the traveling direction. The cross-sectional shape of the irradiated light beam is similar to the cross-sectional shape of the emitted light beam. Since the size and shape of the cross section of the irradiated light beam are constant at an arbitrary position, the size and shape of the irradiation region of the irradiated light beam on the measurement object are different even when the height of the measurement object on the stage is different. Will be equal. As a result, when measuring a measurement object having a plurality of portions having different heights, it is possible to suppress variations in the accuracy of the measurement results of the plurality of portions.

  Here, the direction including the central axis of the irradiation light beam of the second light projecting device and parallel to the intersecting line of the surface perpendicular to the upper surface of the stage and the upper surface of the stage is referred to as a third direction, A direction perpendicular to and parallel to the upper surface of the stage is referred to as a fourth direction. Also in the second light projecting device, the irradiation light beam is irradiated obliquely from above on the upper surface of the stage, so that the irradiation region of the irradiation light beam on the upper surface of the stage is expanded in the third direction with respect to the cross section of the irradiation light beam. In the fourth direction, it is not enlarged.

  In this case, the irradiation region is enlarged at the same ratio in the third direction with respect to the cross section of the irradiation light beam at an arbitrary position in the fourth direction. The size and shape of the cross section of the reflected light beam traveling from the upper surface of the stage toward the light receiving device is constant at an arbitrary position in the traveling direction.

  As described above, the cross section of the reflected light beam toward the light receiving device is enlarged at a certain ratio in the third direction at an arbitrary position in the fourth direction with respect to the cross section of the outgoing light beam, and is at an arbitrary position in the third direction. In the fourth direction, it is enlarged at a constant ratio. Therefore, it is possible to easily calculate at which position of the light receiving surface of the light receiving device the light beam emitted from any position on the output surface of the second pattern generation unit is incident. Thereby, for example, the same arithmetic expression can be used for any position on the light receiving surface of the light receiving device. As a result, the calculation processing for the shape measurement of the triangulation method is simplified and the measurement time can be shortened. In addition, since it is not necessary to use an expensive processing apparatus having high performance, the cost of the shape measuring apparatus can be reduced.

  As described above, it is possible to measure the shape of the triangulation method with high accuracy based on the measurement light beam projected from the first light projecting device and the measurement light beam projected from the second measurement device. .

  (8) In the second plane including the optical axis of the second light projecting device from the second light projecting device toward the upper surface of the stage and the optical axis of the light receiving device from the upper surface of the stage toward the light receiving device, The length of the irradiation region of the measurement light beam on the upper surface may be larger than the width of the reflected light beam that can be received by the light receiving device.

  According to the above configuration, the length of the irradiation region of the measurement light beam on the upper surface of the stage is larger than the width of the reflected light beam that can be received by the light receiving device in the second surface. When measuring the shape of the object, it is possible to reduce the occurrence of non-measurable parts in the measurement object compared to the case where the irradiation area of the measurement light beam on the upper surface of the stage coincides with the light receiving area. .

  (9) The angle formed by the optical axis of the second light projecting device from the second light projecting device toward the upper surface of the stage and the axis orthogonal to the upper surface of the stage is represented by α, and the second in the second plane The width of the measurement light beam guided from the light projecting device to the upper surface of the stage is represented by wp, the width of the reflected light beam that can be received by the light receiving device in the second surface is represented by wi, and can be measured in the optical axis direction of the light receiving device. When the size of the range is represented by 2 · v, the relationship of wp ≧ wi · cos α + 2 · v · sin α may be satisfied.

  In this case, by placing the measurement object on the light receivable region, the irradiation light beam from the second light projecting device over the entire measurement object within the measurable range in the optical axis direction of the light receiving device. Can be irradiated. Therefore, it is possible to further reduce the occurrence of a portion that cannot be measured.

  (10) The first light projecting device and the second light projecting device are configured to measure at least a part of the irradiation region of the measurement light beam from the first light projecting device and the second light projecting device on the upper surface of the stage. It may be arranged on one side and the other side of the surface including the optical axis of the light receiving device from the upper surface of the stage toward the light receiving device so that at least a part of the irradiation region of the light flux overlaps.

  In this case, the measurement light beam can be projected from a plurality of directions different from each other on the measurement object placed on the upper surface of the stage. Accordingly, when there is a portion that cannot be measured by the measurement light beam projected from the first light projecting device, the shape of the portion that cannot be measured is changed to the measurement light beam projected from the second light projection device. Can be measured. Similarly, when there is a portion that cannot be measured by the measurement light beam projected from the second light projecting device, the shape of the portion that cannot be measured is changed to the measurement light beam projected from the first light projection device. Can be measured. As a result, the portion that cannot be measured can be further reduced.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to measure the shape of a measuring object for a short time and with high precision, the cost reduction of a shape measuring apparatus is implement | achieved.

It is a block diagram which shows the structure of the shape measuring apparatus which concerns on one embodiment of this invention. It is a schematic diagram which shows the structure of the measurement part of the shape measuring apparatus of FIG. It is an external appearance perspective view of the measurement part of the shape measuring apparatus of FIG. It is a figure for demonstrating the principle of a triangulation system. It is a figure which shows an example of GUI of the display part at the time of operation mode selection. It is a figure which shows an example of GUI of the display part at the time of operation mode selection. It is a figure which shows an example of GUI of the display part after shape measurement processing execution. It is a figure for demonstrating the function of the both-sides telecentric optical system of the light projection part of FIG. It is a figure which shows the positional relationship of the pattern production | generation part with respect to a stage, and a both-side telecentric optical system. (A) is a figure which shows the pattern emission surface of FIG. 9, (b) is a figure which shows the irradiation area | region on the mounting surface of the stage of FIG. It is a figure for demonstrating the relationship between the position of the some pixel which comprises the pattern emission surface of FIG. 9, and the position of the some part of the irradiation area | region corresponding to a some pixel, respectively. It is a figure for demonstrating the measurement part which concerns on a reference example. It is a figure which shows the irradiation area | region on the mounting surface of the stage of FIG. It is a figure for demonstrating the relationship between the position of the some pixel which comprises the pattern emission surface of FIG. 12, and the position of the some part of the irradiation area | region each corresponding to a some pixel. It is a figure for demonstrating the more preferable relationship between the irradiation area | region and light receivable area | region in an optical axis passage surface.

[1] Configuration of Shape Measuring Device FIG. 1 is a block diagram showing a configuration of a shape measuring device according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a configuration of a measurement unit of the shape measuring apparatus 500 of FIG. FIG. 3 is an external perspective view of the measuring unit of the shape measuring apparatus 500 of FIG. Hereinafter, the shape measuring apparatus 500 according to the present embodiment will be described with reference to FIGS. 1, 2, and 3.

  As shown in FIG. 1, the shape measuring apparatus 500 includes a measuring unit 100, a PC (personal computer) 200, a control unit 300, and a display unit 400. The measurement unit 100 is, for example, a microscope, and includes a plurality of light projecting units 110A and 110B, a light receiving unit 120, an illumination light output unit 130, a stage 140, and a control board 150. As shown in FIG. 2, each of the light projecting units 110A and 110B includes a measurement light source 111, a pattern generating unit 112, a plurality of lenses 113, 114, and 115, a diaphragm 116, and a plurality of bending mirrors 117 and 118. The light receiving unit 120 includes a plurality of cameras 121A, 121B, a plurality of lenses 122, 123A, 123B, a half mirror 124, and diaphragms 125A, 125B. On the stage 140, the measuring object S is placed.

  As shown in FIG. 3, the stage 140 is provided on the pedestal 190. A support column 191 is provided so as to extend upward from the base 190. An optical system support 192 is attached to the upper end of the column 191. The optical system support 192 supports the light receiving unit 120 so as to be positioned above the stage 140. The optical system support 192 supports the two light projecting units 110A and 110B so as to be positioned obliquely above the stage 140, respectively. The two light projecting units 110 </ b> A and 110 </ b> B are arranged symmetrically across a plane that includes the optical axis ROA of the light receiving unit 120 and extends in the front-rear direction of the measurement unit 100.

  The measurement light source 111 of each of the light projecting units 110A and 110B is, for example, a halogen lamp that emits white light. The measurement light source 111 may be another light source such as a white LED (light emitting diode) that emits white light.

  As shown in FIGS. 2 and 3, the light emitted from the measurement light source 111 is appropriately collected by the lens 113, reflected by the bending mirror 117, and enters the pattern generation unit 112.

  Here, the lens 113 is a collimating lens. Thereby, the spread angle of the light incident on the pattern generation unit 112 is adjusted to be within a minute predetermined range. Thereby, the light beam incident on the pattern generation unit 112 can be regarded as a parallel light beam. Note that when the light emitted from the measurement light source 111 is parallel light or light having an extremely small divergence angle, the lens 113 may not be provided.

  The pattern generation unit 112 is, for example, a DMD (digital micromirror device). In this case, the pattern generation unit 112 has a pattern emission surface 112S (FIG. 3) composed of a plurality of micromirrors arranged in a matrix. A plurality of pixels are respectively configured by the plurality of micromirrors. The pattern generation unit 112 may be a transmissive LCD (liquid crystal display), a reflective LCD, an LCOS (Liquid Crystal on Silicon), or a mask. The pattern generation unit 112 generates a light beam (hereinafter referred to as a measurement light beam) having a preset shape measurement pattern and a predetermined intensity (brightness) from incident light, and the generated measurement light beam. Is emitted from the pattern emission surface 112S.

  The measurement light beam emitted from the pattern generation unit 112 is converted into a light beam having a diameter larger than the size of the measurement object S by the plurality of lenses 114 and 115 and the diaphragm 116, and then reflected by the bending mirror 118 and is stored in the stage 140. The upper measurement object S is irradiated. In the present embodiment, the double-sided telecentric optical system TT is configured by the plurality of lenses 114 and 115 and the diaphragm 116. Details of the both-side telecentric optical system TT in each of the light projecting units 110A and 110B will be described later.

  In the light receiving unit 120, the measurement light beam reflected above the stage 140 by the measurement object S enters the lens 122 of the light receiving unit 120. Part of the measurement light beam incident on the lens 122 passes through the half mirror 124, is condensed and imaged by the lens 123A and the diaphragm 125A, and is received by the camera 121A. The remainder of the measurement light beam incident on the lens 122 is reflected by the half mirror 124, condensed and imaged by the plurality of lenses 123 </ b> B and the diaphragm 125 </ b> B of the light receiving unit 120, and received by the camera 121 </ b> B.

  In the light receiving unit 120 according to the present embodiment, as described later, one side telecentric optical system corresponding to the camera 121A is configured by the lenses 122, 123A and the diaphragm 125A. The lenses 122 and 123B and the diaphragm 125B constitute another double-sided telecentric optical system corresponding to the camera 121B.

  Each of the cameras 121A and 121B is, for example, a CCD (charge coupled device) camera including an imaging device 121a and a lens. The image sensor 121a is, for example, a monochrome CCD (charge coupled device). The image sensor 121a may be another image sensor such as a CMOS (complementary metal oxide semiconductor) image sensor. From each pixel of the image sensor 121a, an analog electrical signal (hereinafter referred to as a light reception signal) corresponding to the amount of light received is output to the control board 150 (FIG. 1).

  Unlike a color CCD, a monochrome CCD does not need to be provided with pixels that receive red wavelength light, pixels that receive green wavelength light, and pixels that receive blue wavelength light. Therefore, the measurement resolution of the monochrome CCD is higher than the resolution of the color CCD. Further, unlike a color CCD, a monochrome CCD does not require a color filter for each pixel. Therefore, the sensitivity of the monochrome CCD is higher than that of the color CCD. For these reasons, the cameras 121A and 121B in this example are provided with monochrome CCDs.

  In this example, the illumination light output unit 130 emits red wavelength light, green wavelength light, and blue wavelength light to the measurement object S in a time-sharing manner. According to this configuration, a color image of the measuring object S can be taken by the light receiving unit 120 using a monochrome CCD.

  On the other hand, when the color CCD has sufficient resolution and sensitivity, the image sensor 121a may be a color CCD. In this case, the illumination light output unit 130 does not need to irradiate the measurement object S with red wavelength light, green wavelength light, and blue wavelength light in a time-sharing manner, and irradiates the measurement object S with white light. Therefore, the configuration of the illumination light source 320 can be simplified.

  An A / D converter (analog / digital converter) and a FIFO (First In First Out) memory (not shown) are mounted on the control board 150 of FIG. The light reception signal output from one of the cameras 121A and 121B is sampled at a constant sampling period by the A / D converter of the control board 150 and converted into a digital signal based on the control by the control unit 300. . Digital signals output from the A / D converter are sequentially stored in the FIFO memory. The digital signals stored in the FIFO memory are sequentially transferred to the PC 200 as pixel data.

  As shown in FIG. 1, the PC 200 includes a CPU (Central Processing Unit) 210, a ROM (Read Only Memory) 220, a work memory 230, a storage device 240, and an operation unit 250. The operation unit 250 includes a keyboard and a pointing device. A mouse or a joystick is used as the pointing device.

  The ROM 220 stores a system program. The working memory 230 includes a RAM (Random Access Memory), and is used for processing various data. The storage device 240 is composed of a hard disk or the like. The storage device 240 stores an image processing program and a shape measurement program. The storage device 240 is used for storing various data such as pixel data supplied from the control board 150.

  The CPU 210 generates image data based on the pixel data given from the control board 150. The CPU 210 performs various processes on the generated image data using the work memory 230 and causes the display unit 400 to display an image based on the image data. Further, the CPU 210 gives a driving pulse to a stage driving unit 146 to be described later. The display unit 400 is configured by, for example, an LCD panel or an organic EL (electroluminescence) panel.

  2 and 3, two directions orthogonal to each other in a plane (hereinafter referred to as a placement surface) on the stage 140 on which the measurement object S is placed are defined as an X direction and a Y direction, and arrows Indicated by X and Y. A direction orthogonal to the mounting surface of the stage 140 is defined as a Z direction and is indicated by an arrow Z. A direction rotating around an axis parallel to the Z direction is defined as a θ direction, and is indicated by an arrow θ.

  The stage 140 includes an XY stage 141, a Z stage 142, a θ stage 143, and a tilt stage 144. The XY stage 141 has an X direction moving mechanism and a Y direction moving mechanism. The Z stage 142 has a Z direction moving mechanism. The θ stage 143 has a θ direction rotation mechanism. The tilt stage 144 has a mechanism that can rotate around an axis parallel to the mounting surface (hereinafter referred to as a tilt rotation mechanism). 2 and 3, the tilt stage 144 is not rotated. The XY stage 141, the Z stage 142, the θ stage 143, and the tilt stage 144 constitute a stage 140. The stage 140 further includes a fixing member (clamp) (not shown) that fixes the measuring object S to the placement surface.

  Here, a plane located at the focal point of the light receiving unit 120 and perpendicular to the optical axis ROA of the light receiving unit 120 is referred to as a focal plane of the light receiving unit 120. As shown in FIGS. 2 and 3, the relative positional relationship between the light projecting units 110 </ b> A and 110 </ b> B, the light receiving unit 120, and the stage 140 is the light of the light projecting unit 110 </ b> A from the light projecting unit 110 </ b> A toward the placement surface of the stage 140. The axis TOA1, the optical axis TOA2 of the light projecting unit 110B from the light projecting unit 110B toward the mounting surface of the stage 140, and the optical axis ROA of the light receiving unit 120 from the mounting surface of the stage 140 to the light receiving unit 120 It is set to cross each other at the focal plane. In FIG. 3, illustration of a part of the optical axis TOA2 of the light projecting unit 110B is omitted.

  A plane including the focal point of the light projecting unit 110A and parallel to the XY direction is referred to as a focal plane of the light projecting unit 110A, and a plane including the focal point of the light projecting unit 110B and parallel to the XY direction is defined as the focal plane of the light projecting unit 110B. Call. In this case, each of the light projecting units 110A and 110B is configured such that the focal plane of the light projecting unit 110A and the focal plane of the light projecting unit 110B intersect at a position including the focal point of the light receiving unit 120.

  The center of the rotation axis of the θ stage 143 in the θ direction coincides with the optical axis of the light receiving unit 120. Therefore, when the θ stage 143 is rotated in the θ direction, the measuring object S can be rotated within the field of view around the rotation axis without removing the measuring object S from the field of view. Further, the XY stage 141, the θ stage 143, and the tilt stage 144 are supported by the Z stage 142.

  That is, even if the θ stage 143 is rotated in the θ direction or the tilt stage 144 is rotated in the tilt direction, the center axis of the light receiving unit 120 and the movement axis of the Z stage 142 do not shift. It is configured. Here, the tilt direction is a rotation direction about an axis parallel to the placement surface. With this configuration, even when the position or orientation of the measurement object S is changed, the stage 140 is moved in the Z direction to synthesize a plurality of images respectively captured at a plurality of different focal positions of the light receiving unit 120. It becomes possible.

  Stepping motors are used for the X direction moving mechanism, the Y direction moving mechanism, the Z direction moving mechanism, the θ direction rotating mechanism, and the tilt rotating mechanism of the stage 140, respectively. The X direction moving mechanism, the Y direction moving mechanism, the Z direction moving mechanism, the θ direction rotating mechanism, and the tilt rotating mechanism of the stage 140 are driven by the stage operation unit 145 or the stage driving unit 146 in FIG.

  The user manually operates the stage operation unit 145 to move the mounting surface of the stage 140 in the X direction, the Y direction, or the Z direction relative to the light receiving unit 120, or the θ direction or tilt. Can be rotated in the direction. The stage driving unit 146 moves the stage 140 relative to the light receiving unit 120 in the X direction, the Y direction, or the Z direction by supplying current to the stepping motor of the stage 140 based on the driving pulse given from the PC 200. Or can be rotated in the θ direction or the tilt direction.

  An encoder is attached to a stepping motor used for each of the X direction moving mechanism, Y direction moving mechanism, Z direction moving mechanism, θ direction rotating mechanism, and tilt rotating mechanism of the stage 140. The output signal of each encoder is given to the CPU 210, for example. Based on the signal given from each encoder of the stage 140, the CPU 210 has a position in the X direction (X position), a position in the Y direction (Y position), a position in the Z direction (Z position), The amount of change in the rotation angle in the θ direction (θ rotation angle) or the rotation angle in the tilt direction can be calculated.

  In the present embodiment, stage 140 is an electric stage that can be driven by a stepping motor and can be manually operated, but is not limited thereto. The stage 140 may be an electric stage that can be driven only by a stepping motor, or may be a manual stage that can be operated only manually.

  1 includes a control board 310 and an illumination light source 320. A CPU (not shown) is mounted on the control board 310. The CPU of the control board 310 controls the light projecting units 110A and 110B, the light receiving unit 120, and the control board 150 based on a command from the CPU 210 of the PC 200.

  The illumination light source 320 includes, for example, three LEDs that emit red light, green light, and blue light. By controlling the luminance of the light emitted from each LED, light of an arbitrary color can be generated from the illumination light source 320. Light generated from the illumination light source 320 (hereinafter referred to as illumination light) is output from the illumination light output unit 130 of the measurement unit 100 through a light guide member (light guide). Note that the illumination light source 320 may be provided in the measurement unit 100 without providing the illumination light source 320 in the control unit 300. In this case, the illumination light output unit 130 is not provided in the measurement unit 100.

  The illumination light output unit 130 of FIG. 2 has an annular shape and is disposed above the stage 140 so as to surround the light receiving unit 120. Thereby, illumination light is irradiated to the measuring object S from the illumination light output unit 130 so that no shadow is generated.

  As shown in FIG. 3, in the light receiving unit 120, the optical axis ROA from the half mirror 124 toward the camera 121B extends in the Y direction. Further, in the light projecting unit 110A, the optical axis TOA1 extending from the pattern generating unit 112 toward the bending mirror 118 extends in the Y direction. Furthermore, in the light projecting unit 110B, the optical axis TOA2 from the pattern generation unit 112 toward the bending mirror 118 extends in the Y direction.

  As described above, in the measurement unit 100, by using the half mirror 124 and the plurality of bending mirrors 117 and 118, a part of the optical axis ROA of the light receiving unit 120 and the optical axes TOA1 and TOA2 of the light projecting units 110A and 110B. Are parallel to each other.

  Thereby, the portion of the optical system between the half mirror 124 and the camera 121B in the light receiving unit 120 and the portion of the optical system between the pattern generation unit 112 and the bending mirror 118 in the light projecting units 110A and 110B are X It is supported by the optical system support 192 so as to be aligned in the direction. This prevents the configuration of the measurement unit 100 including a plurality of types of optical systems from increasing in size in the XZ direction.

[2] Shape Measurement of Measurement Object (1) Shape Measurement by Triangular Distance Measurement In the measurement unit 100, the shape of the measurement object S is measured by the triangular distance measurement method. FIG. 4 is a diagram for explaining the principle of the triangulation system. As shown in FIG. 4, for example, an angle γ between the optical axis of the light beam emitted from the light projecting unit 110A and the optical axis of the reflected light incident on the light receiving unit 120 (the optical axis of the light receiving unit 120) is set in advance. The The angle γ is larger than 0 degree and smaller than 90 degrees.

  When the measurement object S is not placed on the stage 140, the light beam emitted from the light projecting unit 110 </ b> A is reflected by the point O on the placement surface of the stage 140 and enters the light receiving unit 120. On the other hand, when the measuring object S is placed on the stage 140, the light beam emitted from the light projecting unit 110 </ b> A is reflected by the point A on the surface of the measuring object S and enters the light receiving unit 120.

  If the distance in the X direction between the point O and the point A is d, the height h of the point A of the measuring object S with respect to the mounting surface of the stage 140 is given by h = d ÷ tan (γ). The CPU 210 of the PC 200 in FIG. 1 measures the distance d between the point O and the point A in the X direction based on the pixel data of the measurement object S given by the control board 150. Further, the CPU 210 calculates the height h of the point A on the surface of the measuring object S based on the measured distance d. By calculating the heights of all points on the surface of the measuring object S, the three-dimensional shape of the measuring object S is measured.

  At the time of measuring the shape of the triangulation method, in order to irradiate all the points on the surface of the measuring object S with the measurement light beam, various kinds of projections from the light projecting units 110A and 110B in FIG. A measurement light beam having a pattern is emitted. The pattern of the measurement light beam is controlled by the pattern generation unit 112 in FIG.

  For example, as a first pattern, a measurement light beam (hereinafter referred to as a linear measurement light beam) having a linear cross section parallel to the Y direction is emitted from the light projecting units 110A and 100B. Further, as the second pattern, a measurement light beam (hereinafter referred to as a sine wave measurement light beam) having a linear cross section parallel to the Y direction and a pattern in which the intensity changes in a sine wave shape in the X direction is projected. The light is emitted from the portions 110A and 100B a plurality of times (in this example, four times). Furthermore, as a third pattern, a measurement light beam having a linear cross section parallel to the Y direction and aligned in the X direction (hereinafter referred to as a striped measurement light beam) is emitted from the light projecting units 110A and 100B a plurality of times ( It is emitted 16 times in this example. Further, as a fourth pattern, a measurement light beam (hereinafter referred to as a code-shaped measurement light beam) having a linear cross section parallel to the Y direction and in which a bright portion and a dark portion are arranged in the X direction is a light projecting unit 110A. , 100B is emitted a plurality of times (in this example, four times). The ratio of the bright part and the dark part of the cord-shaped measurement light beam is 50%.

  The method of scanning the above-described line-shaped measurement light beam on the measurement object S is generally called a light cutting method. On the other hand, the method of irradiating the measuring object S with a sinusoidal measurement light beam, a striped measurement light beam or a code-shaped measurement light beam is classified as a pattern projection method. Among the pattern projection methods, a method of irradiating the measuring object S with a sinusoidal measuring light beam or a striped measuring light beam is classified as a phase shift method, and a method of irradiating the measuring object S with a code-like measuring light beam is a spatial code. Classified into law.

  In the measurement unit 100 according to the present embodiment, the measurement light beam can be projected from a plurality of (two in this example) directions different from each other on the measurement object S placed on the upper surface of the stage 140. . Thus, when there is a portion that cannot be measured by the measurement light beam projected from the light projecting unit 110A, the shape of the non-measurable portion is measured using the measurement light beam projected from the light projection unit 110B. be able to. Similarly, when there is a portion that cannot be measured by the measurement light beam projected from the light projecting unit 110B, the shape of the non-measurable portion is measured using the measurement light beam projected from the light projection unit 110A. be able to. As a result, it is possible to reduce the portion of the measuring object S that cannot be measured.

(2) Receiving system measurable range In the shape measurement of the triangulation method, the images of the cameras 121A and 121B are taken from the measuring object S as the position of the surface of the measuring object S moves away from the focus of the light receiving unit 120 in the optical axis direction. The degree of blur of light incident on the element 121a is increased. Similarly, as the position of the surface of the measuring object S becomes closer to the focal point of the light receiving unit 120, the degree of blurring of light incident from the measuring object S to the image sensor 121a of the cameras 121A and 121B increases. The degree of blurring of light incident on the image sensor 121a of the light receiving unit 120 varies depending on, for example, the magnification and numerical aperture of the light receiving optical system of the light receiving unit 120.

  When the degree of blur of light incident on the light receiving unit 120 from the measurement object S increases, the measurement accuracy of the height of the surface of the measurement object S decreases. Therefore, in the present embodiment, the range in the optical axis direction of the light receiving unit 120 that is considered to be able to obtain a measurement accuracy of a certain level or more is determined in advance for each shape measuring device 500 according to the configuration of the light receiving unit 120. . In the following description, the range in the Z direction of the light receiving unit 120 determined in advance in this way is referred to as a light receiving system measurable range. In the present embodiment, the light receiving system measurable range is set so as to correspond to the cameras 121A and 121B, respectively.

  For example, the light receiving system measurable range corresponding to the camera 121 </ b> A is obtained when the measuring object S is moved in the optical axis direction of the light receiving unit 120 while the surface of the measuring object S is irradiated with the striped measurement light beam. The degree of blur of light incident on the image sensor 121a of 121A is determined in a range that does not exceed a predetermined threshold value. Similarly, the light receiving system measurable range corresponding to the camera 121B is obtained when the measuring object S is moved in the optical axis direction of the light receiving unit 120 in a state where the surface of the measuring object S is irradiated with the striped measurement light beam. The degree of blurring of light incident on the image sensor 121a of the camera 121B is determined in a range that does not exceed a predetermined threshold value.

  The light receiving system measurable range corresponding to the camera 121A includes the range of the depth of field of the light receiving optical system corresponding to the camera 121A and is larger than the range of the depth of field of the light receiving optical system corresponding to the camera 121A. Similarly, the light receiving system measurable range corresponding to the camera 121B includes the range of the depth of field of the light receiving optical system corresponding to the camera 121B and is larger than the range of the depth of field of the light receiving optical system corresponding to the camera 121B. large.

[3] Microscope Mode and Shape Measurement Mode The shape measurement apparatus 500 according to the present embodiment can operate in the microscope mode and in the shape measurement mode. 5 and 6 are diagrams illustrating an example of a GUI (Graphical User Interface) of the display unit 400 when the operation mode is selected. As shown in FIGS. 5 and 6, an image display area 550 and setting change areas 570 and 580 are displayed on the display unit 400. In the image display area 550, an image of the measuring object S captured by the light receiving unit 120 is displayed.

  In the setting change area 570, a brightness selection field 571, a brightness setting bar 572, a display switching field 573, a magnification switching field 574, a magnification selection field 575, and a focus adjustment field 576 are displayed. The brightness setting bar 572 includes a slider 572s that can move in the horizontal direction.

  The user can switch the exposure time method of the light receiving unit 120 between auto (automatic) and manual by selecting the exposure time method of the light receiving unit 120 in the brightness selection field 571. When manual is selected as the exposure time method of the light receiving unit 120, the user operates the operation unit 250 of the PC 200 to move the slider 572 s of the brightness setting bar 572 in the horizontal direction, whereby the light receiving unit 120. The exposure time can be adjusted. The user can switch the image display type between color and monochrome by selecting the image display type from the display switching field 573.

  In the light receiving unit 120, the magnification of the lens corresponding to one camera 121A is lower than the magnification of the lens corresponding to the other camera 121B. Therefore, in this example, one camera 121A is called a low magnification camera, and the other camera 121B is called a high magnification camera. The user can switch between the low-magnification camera (camera 121A) and the high-magnification camera (camera 121B) of the light receiving unit 120 by selecting the magnification of the camera in the magnification switching field 574. Accordingly, the camera that outputs the light reception signal to the control board 150 is switched between the low-magnification camera (camera 121A) and the high-magnification camera (camera 121B).

  The light receiving unit 120 has a digital zoom function. In this example, by combining the two cameras 121A and 121B and the digital zoom function, the camera magnification can be substantially changed to two or more types. The user can set the magnification of the camera of the light receiving unit 120 by selecting the magnification in the magnification selection field 575. When the digital zoom function is used, the light receiving system measurable range determined for each type of camera (high magnification camera and low magnification camera) may be corrected based on the amount of change in magnification.

  The user can change the focus position of the light receiving unit 120 in the Z direction by a distance corresponding to the input numerical value by inputting a numerical value in the focus adjustment field 576. The focus position of the light receiving unit 120 is changed by changing the position of the Z stage 142 of the stage 140, that is, the relative distance in the Z direction between the light receiving unit 120 and the measurement object S.

  In the setting change area 580, a microscope mode selection tab 580A and a shape measurement mode selection tab 580B are displayed. When the microscope mode selection tab 580A is selected, the shape measuring apparatus 500 operates in the microscope mode. In the microscope mode, the measurement object S is irradiated with illumination light from the illumination light output unit 130. In this state, the enlarged observation of the measuring object S can be performed.

  As shown in FIG. 5, when the microscope mode selection tab 580 </ b> A is selected, a tool selection field 581 and a shooting button 582 are displayed in the setting change area 580. The user can capture (capture) an image of the measurement object S displayed in the image display area 550 by operating the capture button 582.

  The tool selection field 581 displays a plurality of icons for selecting a plurality of execution tools. The user operates one of the plurality of icons in the tool selection field 581 to perform planar measurement of the image of the measurement object S being observed, insertion of a scale in the image, depth synthesis, and comment on the image. Execution tools such as insertion or image improvement can be executed.

  For example, when execution of plane measurement is selected, a measurement tool display field 581a and an auxiliary tool display field 581b are displayed below the tool selection field 581. The measurement tool display field 581a is used for measuring the distance between two points, measuring the distance between two parallel lines, measuring the diameter or radius of a circle, and measuring the angle formed by two straight lines. Multiple icons are displayed. In the auxiliary tool display field 581b, a plurality of icons for executing auxiliary drawing such as dots, lines or circles on the image in the image display area 550 are displayed.

  When the shape measurement mode selection tab 580B is selected, the shape measurement apparatus 500 operates in the shape measurement mode. As shown in FIG. 6, when the shape measurement mode selection tab 580B is selected, a measurement button 583 is displayed in the setting change area 580. The user can execute a shape measurement process for measuring the three-dimensional shape of the measuring object S by the triangulation method by operating the measurement button 583 after the preparation for the shape measurement is completed.

  FIG. 7 is a diagram illustrating an example of the GUI of the display unit 400 after execution of the shape measurement process. As shown in FIG. 7, the image of the measuring object S is displayed in the image display area 550 based on the data generated in the shape measurement process. The user can confirm the measurement result of the measurement object S or perform simple measurement on the composite image.

[4] Double-sided telecentric optical system (1) About the light projecting unit FIG. 8 is a diagram for explaining the function of the double-sided telecentric optical system TT of the light projecting unit 110A of FIG. As shown in FIG. 8, in the present embodiment, the pattern generation unit 112 is arranged so that the pattern emission surface 112S of the pattern generation unit 112 is included in the focal plane FS1 on one side of the both-side telecentric optical system TT.

  In this case, the chief ray PR of the measurement light beam (hereinafter referred to as an output light beam) emitted from the pattern emission surface 112S to the both-side telecentric optical system TT is parallel to the optical axis TOA1. As described above, the divergence angle of the light incident on the pattern generation unit 112 is adjusted to be within a predetermined range by the lens 113 that is a collimating lens. Thereby, the spread angle of the emitted light beam is also within a predetermined range. Therefore, the size and shape of the cross section of the emitted light beam are substantially constant at any position on the optical axis TOA1.

  Also, the principal ray PR of the measurement light beam (hereinafter referred to as the irradiation light beam) irradiated from the both-side telecentric optical system TT onto the mounting surface of the stage 140 in FIG. 3 is also parallel to the optical axis TOA1. Similar to the emitted light beam, the spread angle of the irradiated light beam is also within a predetermined range. Thereby, the size and shape of the cross section of the irradiated light beam are substantially constant at an arbitrary position on the optical axis TOA1.

  As described above, when the pattern emission surface 112S is included in the focal plane FS1 on one side of the both-side telecentric optical system TT, when the irradiation light beam is irradiated onto the measurement object S, the measurement object S in the direction of the optical axis TOA1. The greater the position of is located away from the focal plane FS2 on the other side of the both-side telecentric optical system TT, the greater the degree of blurring of the pattern projected onto the measuring object S.

  When the degree of blurring of the pattern projected onto the measuring object S increases, the measurement accuracy of the surface shape of the measuring object S decreases. Therefore, a range in the optical axis direction of the light projecting unit 110A considered to be able to obtain a measurement accuracy of a certain level or more is determined as the light projecting system measurable range CA.

  In the example of FIG. 8, the range from the position separated from the focal plane FS2 by the distance SF to the position separated from the focal plane FS2 by the distance SB in the optical axis direction of the both-side telecentric optical system TT can be measured. Shown as range CA.

  The light projecting system measurable range CA includes the focal depth range of the double telecentric optical system TT and is larger than the focal depth range of the double telecentric optical system TT.

  As described above, if the size and shape of the cross section of the irradiated light beam are substantially constant at an arbitrary position, the irradiated light beam on the measurement object S even when the height of the measurement object S on the stage 140 is different. The cross-sectional size and shape of each are substantially equal. As a result, when measuring the measuring object S having a plurality of portions having different heights, variations in the accuracy of the measurement results of the plurality of portions are suppressed.

  Also in the light projecting unit 110B of FIG. 3, the pattern generating unit 112 is arranged so that the pattern emission surface 112S of the pattern generating unit 112 is included in the focal plane FS1 on one side of the both-side telecentric optical system TT. Thereby, the same effect as the above example can be obtained.

(2) About the light receiving unit In the shape measuring apparatus 500, not only the light projecting units 110A and 110B but also the light receiving unit 120 uses a both-side telecentric optical system. Specifically, in the light receiving section 120, one double-sided telecentric optical system is configured by the lenses 122 and 123A and the diaphragm 125A in FIG. 3, and another double-sided telecentric optical system is configured by the lenses 122 and 123B and the diaphragm 125B. .

  In each double-sided telecentric optical system, the principal ray of the reflected light beam from the measuring object S toward the lens 122 is parallel to the optical axis of one double-sided telecentric optical system. As described above, when the spread angle of the irradiated light beam is within a predetermined range, the spread angle of the reflected light beam is also within the predetermined range. Thereby, the size and shape of the cross section of the reflected light beam from the measuring object S toward the lens 122 are substantially constant at an arbitrary position on the optical axis ROA.

  In this case, even when the height of the measuring object S on the stage 140 is different, the size and shape of the cross section of the reflected light beam on the measuring object S are substantially equal. As a result, when measuring the measuring object S having a plurality of portions having different heights, variations in the accuracy of the measurement results of the plurality of portions are suppressed.

  In the present embodiment, the range of the focal depth of the both-side telecentric optical system TT of the light projecting units 110A and 110B is set to be larger than the range of the depth of field of each of the both-side telecentric optical systems of the light receiving unit 120. The

  For example, when the magnification of the both-side telecentric optical system TT of the light projecting units 110A and 110B is substantially equal to the magnification of one of the both-side telecentric optical system TT of the light receiving unit 120, the opening of the both-side telecentric optical system TT of the light projecting units 110A and 110B. The number is set to be smaller than the numerical aperture of the one-side telecentric optical system of the light receiving unit 120. Further, when the magnification of the both-side telecentric optical system TT of the light projecting units 110A and 110B is substantially equal to the magnification of the other both-side telecentric optical system of the light receiving unit 120, the aperture of the both-side telecentric optical system TT of the light projecting units 110A and 110B. The number is set to be smaller than the numerical aperture of the other both-side telecentric optical system of the light receiving unit 120. In this case, the range of the depth of focus of the light projecting units 110 </ b> A and 110 </ b> B of the measuring unit 100 is larger than the range of the depth of field of the light receiving unit 120. Thereby, the light projecting system measurable range CA of the light projecting units 110 </ b> A and 110 </ b> B of the measuring unit 100 can be made larger than the light receiving system measurable range of the light receiving unit 120. Therefore, the range of the height of the measuring object S that can be measured with a certain degree of accuracy by the shape measuring apparatus 500 can be determined based on the light receiving system measurable range of the light receiving unit 120.

[5] Arrangement of the Projection Optical System Utilizing the Scheinproof Principle In the following description, the measuring object S is not placed on the stage 140 of FIGS. 2 and 3, and the stage 140 rotates in the upward direction. An area on the mounting surface of the stage 140 that is irradiated with the irradiation light beam from each of the light projecting units 110A and 110B in a state where the irradiation surface is not held (for example, a state where the mounting surface is held horizontally) is referred to as an irradiation area.

  In the measuring unit 100, the optical axes TOA1 and TOA2 of the light projecting units 110A and 110B are respectively directed to the light receiving unit 120 from the mounting surface of the stage 140 in order to perform shape measurement by the triangulation method. Inclined with respect to the direction (Z direction). In such a configuration, when the focal plane FS2 on the other side of the both-side telecentric optical system TT of each of the light projecting units 110A and 110B is orthogonal to the optical axes TOA1 and TOA2, the stage 140 is moved in the Z direction. However, the entire pattern emission surface 112S of the pattern generation unit 112 cannot be focused on the placement surface of the stage 140. Therefore, the measurement accuracy of the measuring object S is lowered. Therefore, in the present embodiment, the arrangement of the components of the light projecting units 110A and 110B is determined as follows.

  FIG. 9 is a diagram illustrating a positional relationship between the pattern generation unit 112 and the both-side telecentric optical system TT with respect to the stage 140. As shown in FIG. 9, the arrangement of the pattern emission surface 112S of the pattern generation unit 112, the both-side telecentric optical system TT, and the placement surface of the stage 140 is determined according to the Scheimpflug theorem.

  Specifically, in a state where the stage 140 is not rotated in the vertical direction and the stage 140 is in a specific Z position, the surface PP including the main plane of the both-side telecentric optical system TT, and the pattern emission surface 112S of the pattern generation unit 112. The pattern generator 112 and the both-side telecentric optical system TT are arranged so that the surface IS including the surface IS and the surface SS including the mounting surface of the stage 140 intersect each other on a common straight line LP.

  When the mounting surface of the stage 140 is included in the focal plane FS2 (FIG. 8) on the other side of the both-side telecentric optical system TT, the focal point of the entire pattern emission surface 112S is focused on the irradiation area 140S on the mounting surface of the stage 140. Fit. Thereby, the measuring object S can be measured with high accuracy.

  Further, in this example, when the stage 140 moves in the Z direction, the degree of blurring of the irradiation light beam applied to the upper surface of the stage 140 is approximately according to the amount of deviation of the mounting surface from the focal plane of the measurement light beam. Change uniformly. Accordingly, by moving the mounting surface of the stage 140 in the Z direction so that the measuring object S is positioned within the light projecting system measurable range CA, the measuring light beam having various patterns can be measured with a certain degree of accuracy. The object S can be easily irradiated.

  FIG. 10A is a diagram showing the pattern emission surface 112S of FIG. 9, and FIG. 10B is a diagram showing the irradiation region 140S on the placement surface of the stage 140 of FIG. As shown in FIG. 10A, the pattern emission surface 112S of FIG. 9 has a rectangular shape. In the following description, it is assumed that parallel light is emitted from the entire surface of the pattern emission surface 112S in FIG. Here, the horizontal length of the pattern emission surface 112S is a, and the vertical length is b. As shown in FIG. 10B, the horizontal length of the irradiation region 140S is A1, and the vertical length of the irradiation region 140S is B1. 10A and 10B, in the pattern emission surface 112S and the irradiation region 140S, the horizontal direction indicates a direction parallel to the straight line LP in FIG. 9, and the vertical direction indicates a straight line LP on the surfaces IS and SS in FIG. The direction orthogonal to is shown.

  The inclination of the surface IS with respect to the surface orthogonal to the optical axes TOA1, TOA2 of the double-sided telecentric optical system TT is φ, the inclination of the surface SS with respect to the surface orthogonal to the optical axes TOA1, TOA2 is θ, and the magnification of the double-sided telecentric optical system TT is Let β. In this case, the horizontal length A1 of the irradiation region 140S and the vertical length B1 of the irradiation region 140S can be expressed by the following formulas (1) and (2), respectively.

A1 = β · a (1)
B1 = (1 / cos θ) · cos φ · β · b (2)
According to the above formulas (1) and (2), the length B1 of the irradiation region 140S in the vertical direction is further (1 /) with respect to the length b of the pattern emission surface 112S enlarged at the magnification β. cosθ) · cosφ. On the other hand, the lateral length A1 of the irradiation region 140S is not enlarged with respect to the lateral length a of the pattern emission surface 112S enlarged at the magnification β.

  In this case, the irradiation region 140S is enlarged at the same ratio in the vertical direction with respect to the cross section of the pattern emission surface 112S, that is, the cross section of the irradiation light beam, at an arbitrary position in the horizontal direction. Further, the irradiation region 140S is enlarged at the same ratio in the horizontal direction with respect to the cross section of the irradiation light beam at an arbitrary position in the vertical direction.

  FIG. 11 is a diagram for explaining the relationship between the positions of a plurality of pixels constituting the pattern emission surface 112S of FIG. 9 and the positions of a plurality of portions of the irradiation region 140S corresponding to the plurality of pixels, respectively.

  FIG. 11A shows a plurality of pixels constituting the pattern emission surface 112S of FIG. Each of the plurality of pixels has a square shape. In FIG. 11A, a black dot indicating the pixel position is attached to the center of each pixel. It is assumed that the pattern emission surface 112S has j pixels in the horizontal direction and k pixels in the vertical direction. In the following description, in order to identify each of the plurality of pixels on the pattern emission surface 112S, for example, the mth position (m is a natural number equal to or less than j) in the horizontal direction and the nth position (n is a natural number equal to or less than k) in the vertical direction. The pixel at is denoted as pixel [m, n]. Further, as shown in FIG. 11A, the x-axis is defined to extend in the horizontal direction with the position of the pixel [1, 1] as the origin, and the y-axis is defined to extend in the vertical direction.

  In this case, if the distance between pixels adjacent to each other in the x-axis direction (pixel pitch) and the distance between pixels adjacent to each other in the y-axis direction (pixel pitch) are U, the position of the pixel [m, n] is (U M, U · n).

  FIG. 11B shows a plurality of portions of the irradiation area 140S of FIG. 9 corresponding to the plurality of pixels of FIG. Here, the plurality of portions of the irradiation region 140S respectively corresponding to the plurality of pixels on the pattern emission surface 112S are the light beams emitted from the plurality of pixels on the pattern emission surface 112S on the placement surface of the stage 140. Refers to multiple parts. In the example of FIG. 11B, a black dot indicating the position of each part is attached to the center of each part. In order to identify each of the plurality of portions in the irradiation region 140S, a portion corresponding to the pixel [m, n] in FIG. 11A is represented as a corresponding portion [m, n]. Further, the x axis is defined so as to extend in the horizontal direction with the position of the corresponding portion [1, 1] as the origin, and the y axis is defined so as to extend in the vertical direction.

  In this case, referring to the above equations (1) and (2), the position of the corresponding portion [m, n] is represented as (β · U · m, (1 / cos θ) · cos φ · β · U · n). be able to. As described above, when a common xy coordinate system is defined on the pattern emission surface 112S and the mounting surface of the stage 140, the x coordinate of the corresponding portion can be expressed by a linear expression using the x coordinate of the corresponding pixel. it can. Further, the y coordinate of the corresponding portion can be expressed by a linear expression using the y coordinate of the corresponding pixel. Therefore, a common linear relationship exists between the positions of the plurality of pixels constituting the pattern emission surface 112S and the positions of the plurality of corresponding portions of the irradiation region 140S corresponding to the plurality of pixels, respectively.

  As shown by the alternate long and short dash line in FIG. 11B, the reflected light beam reflected in the optical axis direction (Z direction) of the light receiving unit 120 of FIGS. 2 and 3 from the rectangular region 121v smaller than the irradiation region 140S in the irradiation region 140S. Enters the camera 121A and the camera 121B of the light receiving unit 120. The size and shape of the cross section of the reflected light beam traveling from the stage 140 mounting surface toward the light receiving unit 120 is substantially constant at an arbitrary position on the optical axis ROA (FIG. 3) of the light receiving unit 120.

  In the light receiving unit 120, the light receiving surface of the image sensor 121a of the camera 121A and the light receiving surface of the image sensor 121a of the camera 121B are orthogonal to the optical axis ROA of the light receiving unit 120, respectively. As a result, on the light receiving surface of each imaging element 121a, the reflected light flux of the rectangular region 121v reduced at a constant ratio with respect to the vertical direction and the horizontal direction is received.

  In this case, it is easy to calculate which light beam emitted from the plurality of pixels on the pattern emission surface 112S of the pattern generation unit 112 is incident on the pixel at which the image sensor 121a of each of the cameras 121A and 121B is incident. Can do.

  Thereby, the same arithmetic expression can be used for any position of each imaging element 121a of the cameras 121A and 121B. Thus, the calculation process for the shape measurement of the triangulation system is simplified and the measurement time can be shortened. In addition, since it is not necessary to use an expensive processing apparatus having high performance, the cost of the shape measuring apparatus 500 can be reduced.

  As a reference example, an example of the measurement unit 100 when an optical system that does not have telecentricity (hereinafter referred to as a non-telecentric optical system) is used instead of the double-sided telecentric optical system TT.

  FIG. 12 is a diagram for explaining the measurement unit 100 according to the reference example. FIG. 12 shows the positional relationship between the pattern generator 112 and the non-telecentric optical system with respect to the stage 140. As shown in FIG. 12, the non-telecentric optical system TX of this example includes a plurality of lenses 114x and 115x having a field angle larger than 0 ° and a diaphragm 116x.

  Also in this example, as in the example of FIG. 9, the arrangement of the pattern emission surface 112S of the pattern generation unit 112, the non-telecentric optical system TX, and the mounting surface of the stage 140 is determined so as to satisfy the Scheimpflug condition. In this case, the pattern generation unit 112 is arranged so that the pattern emission surface 112S is included in one focal plane of the non-telecentric optical system TX, and the mounting surface of the stage 140 is included in the other focal plane of the non-telecentric optical system TX. In this case, the entire pattern emission surface 112S is focused on the irradiation area 140S on the stage 140 mounting surface.

  FIG. 13 is a diagram showing an irradiation region 140S on the mounting surface of the stage 140 of FIG. As shown in FIG. 13, when a non-telecentric optical system TX is used in place of the both-side telecentric optical system TT for the light projecting portions 110A and 110B, the light is placed on the pattern emitting surface 112S of FIG. The irradiation area 140S on the surface is distorted into a trapezoid.

  In this case, the length B1 in the vertical direction of the irradiation region 140S can be expressed by the above formula (2) when the magnification of the non-telecentric optical system TX is β. However, the irradiation region 140S is enlarged at a different ratio in the horizontal direction with respect to the cross section of the irradiation light beam at an arbitrary position in the vertical direction. Therefore, it cannot be expressed in the same manner as the above formula (1).

  FIG. 14 is a diagram for explaining the relationship between the positions of a plurality of pixels constituting the pattern emission surface 112S of FIG. 12 and the positions of a plurality of portions of the irradiation region 140S corresponding to the plurality of pixels, respectively.

  FIG. 14A shows a plurality of pixels constituting the pattern emission surface 112S of FIG. The pattern emission surface 112S in FIG. 12 is the same as the pattern emission surface 112S in FIG. Therefore, also in this example, the position of the pixel [m, n] on the pattern emission surface 112S is represented as (U · m, U · n).

  FIG. 14B shows a plurality of portions of the irradiation area 140S of FIG. 12 corresponding to the plurality of pixels of FIG. Similarly to the example of FIG. 11B, in order to identify each of the plurality of portions in the irradiation region 140S, the portion corresponding to the pixel [m, n] in FIG. write. Further, the x axis is defined so as to extend in the horizontal direction with the position of the corresponding portion [1, 1] as the origin, and the y axis is defined so as to extend in the vertical direction.

  In this case, since the irradiation region 140S of FIG. 12 is distorted in a trapezoidal shape, for example, the x coordinates of a plurality of corresponding portions arranged in the horizontal direction are expressed by different arithmetic expressions at arbitrary positions in the vertical direction.

  Also in FIG. 14B, the rectangular area 121v of the reflected light beam incident on the imaging elements 121a of the cameras 121A and 121B in the irradiation area 140S is indicated by a one-dot chain line. As shown in FIG. 14B, in this example, the distribution of a plurality of corresponding portions is different in a plurality of portions in the rectangular area 121v. Therefore, it is determined on the pattern emission surface 112S whether the light rays emitted from the plurality of pixels on the pattern emission surface 112S of the pattern generation unit 112 are incident on the pixels at the respective imaging elements 121a of the cameras 121A and 121B. It is necessary to calculate for each pixel by different arithmetic processing. In this case, it is easy to calculate which light beam emitted from the plurality of pixels on the pattern emission surface 112S of the pattern generation unit 112 is incident on the pixel at each of the image pickup devices 121a of the cameras 121A and 121B. is not.

  As described above, in this reference example, the calculation process for the shape measurement by the triangulation method is not simplified, and the measurement time is prolonged. In addition, an expensive processing device having high performance is required to repeatedly perform complicated arithmetic processing, and the manufacturing cost of the shape measuring device 500 increases.

[6] Preferred Relationship Between Projection Width and Receiving Width of Measurement Light Beam In the following description, a cross-sectional area of the reflected light beam that can be received by the light receiving unit 120 on the mounting surface of the stage 140 is referred to as a light receiving area. Further, a surface including the optical axes TOA1 and TOA2 of the light projecting units 110A and 110B facing the mounting surface of the stage 140 and the optical axis ROA of the light receiving unit 120 facing the light receiving unit 120 from the upper surface of the stage 140 is an optical axis passing surface. Call it. Furthermore, a space within the range of the light receiving area in the XY direction and within the light receiving system measurable range in the Z direction is referred to as a measurable space.

  FIG. 15 is a diagram for explaining a preferable relationship between the irradiation region 140S and the light receiving region on the optical axis passing surface. For example, when the mounting surface of the stage 140 is located at the focal point of the light receiving unit 120, the measurement object is in a range from the mounting surface of the stage 140 in the Z direction to a height v that is ½ of the light receiving system measurable range. The shape of S can be measured with a certain accuracy.

  However, for example, the shape and size of the irradiation region 140S of the irradiation light beam irradiated on the mounting surface of the stage 140 when the output light beam is emitted from the entire pattern emission surface 112S of the pattern generation unit 112 and the shape of the light receiving region 140R. If the measurement object S and the size coincide with each other, there is a possibility that the measurement object S is not irradiated with the irradiated light beam even when the height of the measurement object S is less than or equal to half the height v of the light receiving system measurable range. There is sex.

  For example, in the example of FIG. 15A, as shown by the thick dotted line, the irradiation light beam is not irradiated to a part PA of the measurement object S far from the light projecting units 110A and 110B. Therefore, the shape of a part PA of the measuring object S cannot be measured.

  Therefore, the length of the irradiation region 140S on the mounting surface of the stage 140 on the optical axis passing surface is set to be larger than the length of the light receiving region 140R on the mounting surface of the stage 140 on the optical axis passing surface. It is preferred that

  In this case, the length of the irradiation region 140S on the mounting surface of the stage 140 in the optical axis passage surface matches the length of the light receiving region 140R on the mounting surface of the stage 140 in the optical axis passage surface. Compared to the case, the portion of the measuring object S that is not irradiated with the irradiated light beam can be reduced.

  The length of the irradiation region 140S on the mounting surface of the stage 140 on the optical axis passage surface and the length of the light receiving region 140R on the mounting surface of the stage 140 on the optical axis passage surface are set according to the following conditions. It is more preferable.

  FIG. 15B shows the length of the irradiation region 140S on the mounting surface of the stage 140 in the measurable space CS and the optical axis passing surface, and the light receiving region on the mounting surface of the stage 140 in the optical axis passing surface. A more preferred relationship with the length of 140R is shown. In the example of FIG. 15B, the placement surface of the stage 140 is disposed at the center position of the measurable space CS in the Z direction.

  In this case, if the angle formed by the optical axes TOA1, TOA2 of the light projecting units 110A, 110B facing the placement surface of the stage 140 and the axis orthogonal to the placement surface of the stage 140 is represented by α, the measurable space CS is The maximum range c in the X direction of the mounting surface on which the passing irradiation light beam is projected is a height v that is ½ of the light receiving system measurable range, and the width of the light receiving region 140R within the optical axis passing surface. It can be expressed as follows using wi (the size of the measurable space CS in the X direction).

c = wi + 2 · v · tan α (3)
Further, an irradiation region 140S in the case where an irradiation light beam having a width of wp is irradiated on the mounting surface of the stage 140 in a direction orthogonal to the optical axes TOA1 and TOA2 of the light projecting units 110A and 110B within the optical axis passing surface. The range d in the X direction can be expressed as follows.

d = wp / cos α (4)
As shown in FIG. 15 (b), when d ≧ c, it is possible to irradiate almost all of the measuring object S in the measurable space CS with the irradiation light beam. Therefore, from the above formulas (3) and (4), the width wi in the X direction of the light receiving area 140R in the optical axis passage plane and the optical axes TOA1, 110A and 110B of the light projecting portions 110A and 110B in the optical axis passage plane. When the relationship of the following formula (5) is satisfied with the width wp in the direction orthogonal to TOA2, the portion of the measuring object S located in the measurable space CS that is not irradiated with the irradiated light beam is sufficiently reduced. be able to. Moreover, the part of the measuring object S located in the measurable space CS can be measured with a certain level of accuracy.

wp ≧ wi · cos α + 2 · v · sin α (5)
[7] One Control Example of Image Sensor of Light Receiving Unit and Pattern Generation Unit of Light Emitting Unit (1) Image Sensor of Light Receiving Unit In the present embodiment, the image sensor 121a of camera 121A and the image sensor 121a of camera 121B include The same structure image sensor having the same number of pixels and the same pixel pitch is used. Thereby, the configuration of the light receiving unit 120 is simplified.

  The pattern light beam irradiated on the mounting surface of the stage 140 is reflected on the mounting surface of the stage 140 or the surface of the measuring object S, and then is applied to the image sensors 121a of the low-power and high-power cameras 121A and 121B. Incident. At this time, the pattern light beam incident on the image sensor 121a of the high-power camera 121B as a reflected light beam is adjusted to be larger than the pattern light beam incident on the image sensor 121a of the low-power camera 121A. Therefore, for example, when the stripe-shaped measurement light beam is irradiated on the mounting surface of the stage 140, the number of pixels that receive one stripe pattern of the stripe-shaped measurement light beam incident on the image sensor 121a of the high-power camera 121B is low. The number is larger than the number of pixels that receive one fringe pattern of the fringe measurement light beam incident on the image sensor 121a of the magnification camera 121A.

  In this case, image processing different from the image data acquired from the low magnification camera 121A is applied to the image data acquired from the high magnification camera 121B. For example, a high-intensity Gaussian filter is applied to image data acquired from the high-magnification camera 121B, and a low-intensity Gaussian filter is applied to image data acquired from the low-magnification camera 121A.

(2) One control example of the pattern generation unit of the light projecting unit When the low-magnification camera 121A and the high-magnification camera 121B are used by switching, the pattern generation unit 112 generates them according to the switched camera magnification. You may change the magnitude | size of the pattern light beam to be performed.

  For example, when imaging with a high-magnification camera 121B, a pattern light beam with a fine pitch is irradiated on the mounting surface of the stage 140, and when imaging with a low-magnification camera 121A, a pattern light beam with a coarse pitch is irradiated with the mounting surface of the stage 140. The pattern generation unit 112 may be controlled so as to be irradiated upward.

  Thereby, when using the imaging device having the same structure for the low-magnification and high-magnification cameras 121A and 121B, the number of pixels that receive the pattern luminous flux incident on the imaging device 121a of the camera 121A and the pattern incident on the imaging device 121a of the camera 121B The difference from the number of pixels that receive the luminous flux can be reduced to 0 or reduced. As a result, common image processing can be applied to image data acquired from the high-magnification camera 121B and image data acquired from the low-magnification camera 121A.

[8] Other Embodiments (1) In the above embodiment, the measurement unit 100 includes two light projecting units 110A and 110B. Not only this but the measurement part 100 may have only one light projection part among the two light projection parts 110A and 110B as a structure which irradiates the measurement light beam to the measuring object S. FIG. In this case, the configuration of the measurement unit 100 is simplified.

  (2) In the light receiving unit 120 according to the above-described embodiment, one double-sided telecentric optical system is configured by the lenses 122 and 123A and the diaphragm 125A in FIG. 3, and the other double-sided telecentric optics is formed by the lenses 122 and 123B and the diaphragm 125B. A system is constructed. Alternatively, in the light receiving unit 120, only the lens 122 of FIG. 3 may be configured by a telecentric lens. In this case, the lens 122, 123A and the diaphragm 125A constitute one object side telecentric optical system, and the lens 122, 123B and the diaphragm 125B constitute another object side telecentric optical system.

  Even in this case, the principal ray of the reflected light beam directed from the measuring object S toward the lens 122 is parallel to the optical axis of the one-side telecentric optical system. Thereby, the size and shape of the cross section of the reflected light beam from the measuring object S toward the lens 122 are constant at an arbitrary position on the optical axis ROA. Therefore, even when the height of the measurement object S on the stage 140 is different, the size and shape of the reflection region of the reflected light beam on the measurement object S are equal. As a result, it becomes possible to measure the shape of the measuring object S having different heights with high accuracy.

  (3) In the above-described embodiment, the pattern luminous flux emitted from the pattern exit surface 112S is the same as that of the stage 140 regardless of whether the image is captured by the high magnification camera 121B or the low magnification camera 121A. Irradiated on the mounting surface.

  Not limited to this, each of the light projecting units 110A and 110B may be provided with a zooming mechanism such as a revolver. In this case, for example, when imaging with a high-magnification camera 121B, a pattern light beam with a fine pitch is irradiated onto the mounting surface of the stage 140, and when imaging with a low-magnification camera 121A, a pattern light beam with a coarse pitch is applied to the stage 140. The zooming mechanism can be adjusted so that it is irradiated onto the mounting surface.

  Thereby, when using the imaging device having the same structure for the low-magnification and high-magnification cameras 121A and 121B, the number of pixels that receive the pattern luminous flux incident on the imaging device 121a of the camera 121A and the pattern incident on the imaging device 121a of the camera 121B The difference from the number of pixels that receive the luminous flux can be reduced to 0 or reduced. As a result, common image processing can be applied to image data acquired from the high-magnification camera 121B and image data acquired from the low-magnification camera 121A.

  (4) In the above-described embodiment, the two-branch optical system using the half mirror 124 and the two cameras 121A and 121B are used for the light receiving unit 120 as a zooming mechanism. However, the light receiving unit 120 may be provided with a zoom lens instead of the above-described two-branch optical system. In this case, the image sensor 121a provided in the light receiving unit 120 can be made one.

  When a zoom lens is used for the light receiving unit 120, it is preferable to limit the range adjustable by the zoom lens within a predetermined range when measuring the shape of the triangulation method. Thereby, even when a zoom lens that does not have high telecentricity is used, it is possible to maintain almost the same measurement accuracy as when the object-side telecentric lens is used for the light receiving unit 120.

  When a zoom lens is used for the light receiving unit 120, correction parameters for each magnification may be stored in the work memory 230 or the like in advance. In this case, high measurement accuracy can be maintained by correcting the image data based on the magnification of the zoom lens at the time of shape measurement and the held correction parameter.

  (5) In the light projecting units 110A and 110B shown in FIGS. 2 and 3, the lens 113 and the bending mirrors 117 and 118 may not be provided. In this case, the configuration of the measurement unit 100 is simplified.

  (6) In the above embodiment, the light receiving unit 120 includes a plurality of cameras 121A and 121B having different magnifications. Not limited to this, the light receiving unit 120 may include only one of the two cameras 121A and 121B.

  (7) In the above embodiment, the two light projecting units 110 </ b> A and 110 </ b> B are arranged symmetrically across a plane that includes the optical axis ROA of the light receiving unit 120 and extends in the front-rear direction of the measuring unit 100. Not limited to this, the light projecting units 110 </ b> A and 110 </ b> B may not be arranged symmetrically across a plane that includes the optical axis ROA of the light receiving unit 120 and extends in the front-rear direction of the measuring unit 100. That is, the optical axis passage surface including the optical axis ROA of the light receiving unit 120 from the mounting surface of the stage 140 toward the light receiving unit 120 and the optical axis TOA1 from the light projecting unit 110A to the mounting surface of the stage 140; The optical axis ROA of the light receiving unit 120 from the mounting surface toward the light receiving unit 120 and the optical axis passage surface including the optical axis TOA2 from the light projecting unit 110B toward the mounting surface of the stage 140 may intersect each other. Even in this case, the measurement light beam can be irradiated from different directions onto the measurement object S placed on the stage 140. Thereby, the part which cannot be measured in the measuring object S can be reduced.

[9] Correspondence relationship between each constituent element of claim and each part of the embodiment Hereinafter, an example of correspondence between each constituent element of the claim and each part of the embodiment will be described. It is not limited.

  In the above embodiment, the measuring object S is an example of the measuring object, the shape measuring apparatus 500 is an example of the shape measuring apparatus, the stage 140 is an example of the stage, and the mounting surface of the stage 140 is It is an example of the upper surface of a stage, and 110 A of light projection parts are examples of a 1st light projection apparatus.

  The light receiving unit 120 is an example of a light receiving device, the measurement light source 111 of the light projecting unit 110A is an example of a first light source, and the pattern generating unit 112 of the light projecting unit 110A is an example of a first pattern generating unit. Yes, the double-sided telecentric optical system TT of the light projecting unit 110A is an example of the first double-sided telecentric optical system, and the pattern emission surface 112S of the pattern generation unit 112 of the light projection unit 110A is the emission surface of the first pattern generation unit. It is an example.

  In addition, the optical axis TOA1 of the light projecting unit 110A is an example of the optical axis of the first light projecting device, the optical axis ROA of the light receiving unit 120 is an example of the optical axis of the light receiving device, and from the mounting surface of the stage 140 An optical axis passing surface including the optical axis ROA of the light receiving unit 120 toward the light receiving unit 120 and the optical axis TOA1 from the light projecting unit 110A toward the upper surface of the stage 140 is an example of the first surface, and the mounting surface of the stage 140 An optical axis passing surface including the optical axis ROA of the light receiving unit 120 from the light receiving unit 120 to the light receiving unit 120 and the optical axis TOA2 from the light projecting unit 110B to the mounting surface of the stage 140 is an example of the second surface. The imaging element 121a is an example of a first light receiving element, and the lenses 122 and 123A and the diaphragm 125A constituting one double-sided telecentric optical system in the light receiving unit 120 are examples of the first light receiving optical system, and the camera 121B The imaging device 121a is an example of a second light receiving element.

  Further, in the light receiving unit 120, the lenses 122 and 123B and the diaphragm 125B constituting the other both-side telecentric optical system are examples of the second light receiving optical system, and the light projecting unit 110B is an example of the second light projecting device. The measurement light source 111 of the light projecting unit 110B is an example of the second light source, and the pattern generation unit 112 of the light projection unit 110B is an example of the second pattern generation unit.

  Further, the both-side telecentric optical system TT of the light projecting unit 110B is an example of a second both-side telecentric optical system, and the pattern emission surface 112S of the pattern generation unit 112 of the light projection unit 110B is the output surface of the second pattern generation unit. It is an example, and the optical axis TOA2 of the light projecting unit 110B is an example of the optical axis of the second light projecting device.

  As each constituent element in the claims, various other elements having configurations or functions described in the claims can be used.

  INDUSTRIAL APPLICABILITY The present invention can be effectively used for various shape measuring devices that perform shape measurement using a triangulation system.

DESCRIPTION OF SYMBOLS 100 Measurement part 111 Measurement light source 112 Pattern production | generation part 112S Pattern emission surface 113,114,115,122 Lens 117,118 Mirror 120 Light reception part 121A, 121B Camera 121a Image pick-up element 124 Half mirror 130 Illumination light output part 140 Stage 141 XY Stage 142 Z stage 143 θ stage 144 Tilt stage 145 Stage operation unit 146 Stage drive unit 150 Control board 190 Base 191 Post 192 Optical system support 200 PC
210 CPU
220 ROM
230 Working Memory 240 Storage Device 250 Operation Unit 300 Control Unit 310 Control Board 320 Illumination Light Source 400 Display Unit 500 Shape Measuring Device 550 Image Display Area 570, 580 Setting Change Area 571 Selection Field 572 Setting Bar 573 Display Switch Field 574 Magnification Switch Field 575 Magnification selection field 576 Focus adjustment field 580 Setting change field 581 Tool selection field 582 Shooting button 583 Measurement button CA Projection system measurable range CS Measurable space IS, PP, SS surface FS1, FS2 Focal surface LP Linear PA Partial PR Main Ray S Measuring object SF, SB Distance ROA, TOA1, TOA2 Optical axis TT Both-side telecentric optical system TX Non-telecentric optical system

Claims (10)

A shape measuring device that irradiates a measurement light beam to a measurement object and measures a three-dimensional shape of the measurement object by a triangulation method based on a reflected light beam from the measurement object,
A stage having an upper surface on which a measurement object is placed;
A first light projecting device for projecting a measurement light beam obliquely from above toward the upper surface of the stage;
A light receiving device configured to receive a light beam reflected above the stage from a measurement object placed on the stage and to output a light reception signal indicating the amount of light received;
The first light projecting device includes:
A first light source that generates light;
A first pattern generation unit that generates and emits light having a pattern for shape measurement as a measurement light beam from light generated by the first light source;
A first double-sided telecentric optical system that guides the measurement light beam emitted by the first pattern generation unit to the upper surface of the stage;
In the stage, the first pattern generation unit, and the first both-side telecentric optical system, the exit surface of the first pattern generation unit and the upper surface of the stage are related to the main plane of the first both-side telecentric optical system. A shape measuring device arranged to follow the Scheimpflug principle. In a first plane including an optical axis of the first light projecting device from the first light projecting device toward the upper surface of the stage and an optical axis of the light receiving device from the upper surface of the stage toward the light receiving device. The shape measuring apparatus according to claim 1, wherein the length of the irradiation region of the measurement light beam on the upper surface of the stage is larger than the width of the reflected light beam that can be received by the light receiving device. An angle formed by an optical axis of the first light projecting device from the first light projecting device toward the upper surface of the stage and an axis orthogonal to the upper surface of the stage is represented by α, and the angle within the first surface The width of the measurement light beam guided from the first light projecting device to the upper surface of the stage is represented by wp, and the width of the reflected light beam that can be received by the light receiving device in the first surface is represented by wi. When the size of the measurable range in the optical axis direction is expressed by 2 · v,
wp ≧ wi · cos α + 2 · v · sin α
The shape measuring device according to claim 2, wherein the relationship is satisfied. The light receiving device is:
A first light receiving element;
A first light receiving optical system that guides a reflected light beam from a measurement object placed on the stage to the first light receiving element;
The shape measuring apparatus according to claim 1, wherein the first light receiving optical system is an object-side telecentric optical system or a double-sided telecentric optical system. The range of the depth of focus on the stage of the first both-side telecentric optical system of the first light projecting device is larger than the range of the depth of field of the first light receiving optical system of the light receiving device. Item 5. The shape measuring apparatus according to Item 4. The light receiving device is:
A second light receiving element;
A second light receiving optical system that guides the reflected light beam from the measurement object placed on the stage to the second light receiving element;
The second light receiving optical system is an object side telecentric optical system or a both side telecentric optical system,
The shape measuring apparatus according to claim 4 or 5, wherein a magnification of the first light receiving optical system and a magnification of the second light receiving optical system are different from each other. A second light projecting device for projecting a measurement light beam obliquely from above toward the upper surface of the stage;
The second light projecting device is:
A second light source that generates light;
A second pattern generation unit that generates and emits light having a pattern for shape measurement as measurement light flux from light generated by the second light source;
A second double-sided telecentric optical system that guides the measurement light beam emitted by the second pattern generation unit to the upper surface of the stage;
In the stage, the second pattern generation unit, and the second both-side telecentric optical system, the exit surface of the second pattern generation unit and the upper surface of the stage are related to the main plane of the second both-side telecentric optical system. The shape measuring device according to any one of claims 1 to 6, which is arranged to follow the Scheinproof principle. In a second plane including an optical axis of the second light projecting device from the second light projecting device toward the upper surface of the stage and an optical axis of the light receiving device from the upper surface of the stage toward the light receiving device. The shape measuring device according to claim 7, wherein the length of the irradiation region of the measurement light beam on the upper surface of the stage is larger than the width of the reflected light beam that can be received by the light receiving device. An angle formed by an optical axis of the second light projecting device from the second light projecting device toward the upper surface of the stage and an axis orthogonal to the upper surface of the stage is represented by α, and the angle within the second surface is The width of the measurement light beam guided from the second light projecting device to the upper surface of the stage is represented by wp, and the width of the reflected light beam that can be received by the light receiving device in the second surface is represented by wi. When the size of the measurable range in the optical axis direction is expressed by 2 · v,
wp ≧ wi · cos α + 2 · v · sin α
The shape measuring device according to claim 8, wherein the relationship is satisfied. The first light projecting device and the second light projecting device include at least a part of an irradiation area of the measurement light beam from the first light projecting device and the second light projecting device on the upper surface of the stage. The light beam is disposed on one side and the other side of the surface including the optical axis of the light receiving device from the upper surface of the stage toward the light receiving device so as to overlap with at least a part of the irradiation region of the measurement light beam. The shape measuring device according to claim 9.

Images