JP3715377B2 - Object shape measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an object shape measuring apparatus for measuring the shape and dimensions of an object to be measured from an image of the object to be measured, and relates to improvement in consistency and measurement time reduction in measurement from a plurality of directions and measurement of a plurality of items.
[0002]
[Prior art]
2. Description of the Related Art Some object shape measuring apparatuses having an optical measuring head that have been used conventionally measure the surface shape of an object to be measured by processing an image of the object to be measured. This apparatus irradiates illumination light from the front side or the back side of an object to be measured, and takes a reflected light image or transmitted light image of the object with a CCD camera mounted on a measurement head. The output image of the CCD camera is subjected to image processing to measure a pattern and its size caused by a step on the object surface.
[0003]
FIG. 8 is a side view of a conventional object shape measuring apparatus. This apparatus includes an XY stage 4 on a support base 2. These support base 2 and XY stage 4 have an opening in the center. Light from the illuminator 6 disposed at the lower part of the apparatus passes through the openings of the support base 2 and the XY stage 4 and reaches an optical measurement head 8 disposed at the upper part of the apparatus. On the other hand, the measuring head 8 also has illumination means.
[0004]
The DUT 10 is placed on the opening of the XY stage 4. The illuminator 6 is used, for example, when the object to be measured 10 is thin or when measuring the shape of a through hole, and the CCD camera captures a transmitted image. On the other hand, when the illuminating means of the measuring head 8 is used, a pattern caused by a shadow or a difference in reflectance caused by a step on the surface of the object to be measured 10 is imaged by the CCD camera. The XY stage 4 can be moved in the horizontal plane direction, whereby a wide area of the DUT 10 can be measured. The DUT 10 is, for example, a printed board or a resin molded product.
[0005]
[Problems to be solved by the invention]
The conventional measuring head is arranged vertically above the XY stage 4 and performs measurement only from one direction, that is, only the upper surface of the object to be measured 10 placed on the XY stage 4. Therefore, when measuring both the upper surface and the bottom surface of an object to be measured such as a double-sided printed circuit board, the object to be measured must be turned over and the front and back must be measured separately. In addition, the optical measurement head of the above apparatus can measure the height of the step, but in order to measure the height with higher accuracy, a shape measuring apparatus equipped with another type of measurement head such as a laser displacement meter is used. And had to be measured separately. In this way, the conventional object shape measuring device measures multiple surfaces and multiple measurement items separately, which increases the time required for measurement and the correspondence between each measurement data by separate measurements. There was a problem that it could not be well defined. For example, even when the front side and the back side are measured using the same apparatus, if the object to be measured 10 is turned upside down, the position on the XY stage 4 shifts, and the front side surface shape and the back side surface shape are between. There is a problem that the relative positional relationship between the two is not accurately grasped.
[0006]
The present invention has been made to solve the above-mentioned problems, and provides an object shape measuring apparatus that improves the consistency between measurement data in measurements from a plurality of directions and measurements of a plurality of items, and shortens the measurement time. The purpose is to do.
[0007]
[Means for Solving the Problems]
  In the object shape measuring apparatus according to the present invention, a plurality of optical measuring heads are provided, and the shape of the object to be measured is measured simultaneously from a plurality of measuring directions. The measuring directions of the plurality of optical measuring heads are opposite to each other. Including first and second optical measuring heads oriented;Head moving means for independently moving the first and second optical measuring heads in a plane direction perpendicular to the measuring direction;It has a head relative position detecting means for detecting a relative position between the first optical measuring head and the second optical measuring head in the vertical plane direction..
[0008]
  According to the present invention, a plurality of measurement directions of an object to be measured, for example, shapes viewed from the front side and the back side are measured in a short time. In this case, it is not necessary to reposition the surface to be measured, for example, turning the object to be measured toward the optical measurement head, so that the displacement due to the alignment of the object to be measured with respect to the apparatus varies between measurement directions. The relative positional relationship of the measurement data in each measurement direction is determined with high accuracy, that is, the consistency between the measurement data is improved.Further, the position in the surface direction between the measurement data on both the front and back surfaces can be corrected based on the detected relative position, and the consistency between the measurement data is improved. .
[0009]
In a preferred aspect of the present invention, further, head moving means for moving the first and second optical measuring heads independently of each other in a plane direction perpendicular to the measuring direction, the first and first optical measuring heads. A mode in which each of the two optical measuring heads is moved independently of each other to scan and measure both sides of the object to be measured, and both the first and second optical measuring heads are measured in the vertical plane direction. And a movement control means for controlling the head movement means in accordance with one of a mode for scanning and measuring both sides of the object to be measured.
[0010]
According to this apparatus, for example, the object to be measured is fixed to a holder and does not move, and the first and second optical measuring heads arranged to measure both the front and back surfaces of the object to be measured can move. . Therefore, by controlling both of these measuring heads, measurement is performed while matching the measurement mode in the surface direction between the front and back surfaces and the operation mode in which measurement is performed without taking cooperation between the front and back surfaces, that is, with cooperation. Operating modes are provided. According to the former among these operation modes, measurement can be performed in parallel when the position in the surface direction of the measurement target region is different between the front and back surfaces, and the measurement time is shortened. According to the latter, the measurement having the consistency between the measurement data on both sides is performed.
[0011]
  A preferred embodiment of the present invention is,PreviousIn the aspect in which the first and second optical measuring heads each include an illuminator that emits focused light and a sensor that detects that the light is focused on the surface of the object to be measured, the relative position of the heads The detecting means includes a means for projecting an alignment pattern provided in the irradiator of the first optical measurement head, and a sensor of the second optical measurement head. Means for detecting an optical image, and determining and outputting a relative position between the first optical measurement head and the second optical measurement head from the position of the optical image.
[0015]
According to a preferred aspect of the present invention, the first optical measurement head includes an illuminator that illuminates the object to be measured, and the illuminator is used as transmitted illumination in the measurement by the second optical measurement head. It is characterized by being able to. According to this apparatus, the kind of illumination which can be utilized for a measurement increases. By providing multiple types of illumination, for example, epi-illumination, transmitted illumination, and oblique illumination, for example, illumination that forms an image with a clear shape boundary can be selected to improve the accuracy of shape measurement.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, preferred embodiments of the present invention will be described with reference to the drawings.
[0019]
[Embodiment 1]
FIG. 1 is a side view of a machine main body of an object shape measuring apparatus embodying the present invention used for measuring the shape of a double-sided printed circuit board. This apparatus measures the object to be measured and outputs measurement data such as an image, etc. In addition to the machine main unit shown in FIG. 1, the apparatus is composed of, for example, a small computer or the like, processes measurement data such as image processing, and indicates measurement conditions. A data processing unit (not shown) that performs the above and a controller unit (not shown) that is a circuit that controls the operation of the machine main body.
[0020]
The machine body includes an XY stage 54 on a support base 52. The support base 52 and the XY stage 54 have an opening 56 at the center. On the opening 56 of the XY stage 54, a double-sided printed board 58, which is a measurement object, is placed.
[0021]
The apparatus has two optical measurement heads, an upper measurement head 60 and a lower measurement head 62. The upper measuring head 60 is arranged at the upper part of the apparatus so as to be movable up and down by an arm 66 from the column 64, while the lower measuring head 62 is arranged at the lower part of the apparatus so as to be movable up and down. The measurement direction of the upper measurement head 60 is vertically downward, and images the shape of a wiring pattern or the like formed on the front side surface of the double-sided printed circuit board 58 from the measurement port 60A. The measurement direction of the lower measurement head 62 is a vertically upward direction opposite to the measurement direction of the upper measurement head 60. The lower measurement head 62 images the wiring pattern on the back side surface of the double-sided printed circuit board 58 from the measurement port 62A through the support base 52 and the opening 56 of the XY stage 54.
[0022]
Both measurement heads 60 and 62 are arranged to face each other, and the horizontal coordinates of the measurement positions of both measurement heads coincide with each other. That is, the lower measurement head 62 measures the exact back side of the position measured by the upper measurement head 60 simultaneously. In reality, there may be a slight difference between the horizontal coordinates of each measurement position of both measurement heads. However, such a difference is based on a reference that has alignment patterns at the same horizontal position on both sides. It is grasped by measuring the measurement object. This recognized difference is corrected at the stage of processing the image output from the measuring head. Therefore, in this device, the shape of the front and back sides of the double-sided printed circuit board is measured simultaneously by the two measuring heads, and the horizontal coordinates are aligned, so the mutual relationship between the shapes of both sides is accurately measured. can do.
[0023]
Each of the measurement heads 60 and 62 includes a measurement optical system including an imaging unit such as a CCD camera and an illumination unit that illuminates the object to be measured. As the illumination means, for example, a ring illumination light source arranged on the outer periphery of the measurement ports 60A and 62A and capable of oblique illumination, and a vertical epi-illumination light source emitted from a lens system of a CCD camera are provided. For example, a halogen lamp is used as these light sources. Both measuring heads are fixed in the horizontal direction, but are configured to be movable in the vertical direction so that the surface to be measured can be focused.
[0024]
Next, the operation of this apparatus will be described. The illumination means of each measuring head 60, 62 illuminates the surface of the double-sided printed circuit board 58, and the reflected light image is captured by each CCD camera. The imaging target position of the board is instructed from the data processing unit to the controller unit. The controller unit controls the drive system of the XY stage 54, moves the XY stage 54 in the horizontal direction (that is, the X direction or the Y direction), and holds a desired portion of the double-sided printed circuit board 58 within the imaging range of the CCD camera. Go. In this apparatus, a joystick box can be connected to the controller unit, and the XY stage 54 can be moved by a measurer's joystick operation instead of the data processing unit.
[0025]
The CCD camera outputs an image including a shadow generated due to a step on the substrate surface and a pattern generated due to a difference in reflectance according to the material. First, the data processing unit detects whether or not the CCD camera is focused on the substrate surface from the contrast of light and dark in this image. If not, the data processing unit moves the measurement optical system vertically to focus on the substrate surface. Next, the data processing unit processes the focused image and extracts a shape such as a step edge. The size of the shape is obtained based on the imaging magnification. Further, the height of the step can be measured, for example, on the micron order from the amount of fluctuation in the vertical direction of the measurement optical system.
[0026]
Moreover, in this apparatus, the illumination means of one measurement head can be used as a transmission illumination light source for the other measurement head. If the measurement is made with transmitted illumination, for example, the transmitted light image of the through hole of the printed circuit board has a better contrast than the reflected light image, so that it is possible to measure the through hole shape and position with higher accuracy.
[0027]
As described above, this apparatus can simultaneously measure the shapes of both sides of a double-sided printed circuit board. In consideration of the fact that this device does not require the operation of turning over the object to be measured, the measurement time is less than half that of the conventional device for measuring one side at a time. Further, when the object to be measured is turned over, the positional deviation of the object to be measured in the XY stage 54 before and after that becomes very large compared to the accuracy of the apparatus itself, that is, the horizontal positional relationship is in the micron order. However, since this device measures both sides simultaneously without turning the object to be measured, the relative positional relationship in the horizontal direction of the measured shape of both sides is clear, and the front side and back side And consistent surface shape measurement.
[0028]
In this apparatus, the upper and lower measurement heads are both optical measurement heads. However, for example, one of them may be another measurement head such as a laser displacement meter.
[0029]
[Embodiment 2]
FIG. 2 is a side view of the machine body of the object shape measuring apparatus embodying the present invention. In the figure, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. Similar to the first embodiment, this apparatus includes a data processing unit (not shown) and a controller unit (not shown) in addition to the machine main unit. This apparatus is different from the apparatus according to the first embodiment in that a side measurement head 70 is provided. The side measurement head 70 images the horizontal measurement direction from the measurement port 70A. By providing this side surface measuring head 70, in addition to the top and bottom surfaces of the object 72 to be measured, the side surface viewed from one direction can be measured simultaneously, and multi-directional measurement can be performed quickly. It is also possible to provide a device that further includes a measurement head and performs measurements in more directions at the same time.
[0030]
[Embodiment 3]
FIG. 3 is a side view of the machine body of the object shape measuring apparatus embodying the present invention. Similar to the first embodiment, this apparatus includes a data processing unit (not shown) and a controller unit (not shown) in addition to the machine main unit.
[0031]
The machine main body has a support base 92 installed on the lower housing 90, the support base 92 has an opening 94 in the center, and an object to be measured 96 is placed on the opening 94. This apparatus has two optical measurement heads, an upper measurement head 98 and a lower measurement head 100. Each of these optical measurement heads has the same internal configuration as the measurement heads 60 and 62 of the first embodiment, but differs from the above-described embodiment in that each of the optical measurement heads is arranged so as to be independently movable in the horizontal plane direction. FIG. 4 is a schematic perspective view showing an example of the moving means of the upper measuring head 98. The two columns 102 are slidably attached via ball screws 104 provided at both ends of the lower housing 90, and are moved in the X-axis direction by rotating the ball screws 104 with a motor. Between both struts 102, a ball screw 106 in the Y-axis direction is passed. The upper measuring head 98 is slidably attached to a sliding surface (not shown) via a ball screw 106, and is moved in the Y-axis direction by rotating the ball screw 106 by a motor. The upper measuring head 98 can be freely moved in the horizontal plane direction by such moving means. On the other hand, the lower measuring head 100 is disposed on an XY stage 110 provided in the lower housing 90, and can be freely moved in the X direction and the Y direction. The moving means may use another mechanism.
[0032]
The upper measurement head 98 and the lower measurement head 100 have measurement directions that are vertically downward and vertically upward, respectively, as in the above-described embodiment. However, since both measurement heads 98 and 100 can move independently of each other, the measurement ports 98A are not necessarily provided. , 100A does not necessarily face up. The lower measurement head 100 measures the object 96 to be measured through the opening 94. In order to control the moving means of both measuring heads, the control section and the data processing section provide movement control means. The movement target position information of each measuring head is transferred from the data processing unit to the control unit, and the control unit controls the moving means of each measuring head.
[0033]
The movement control means has, as operation modes, a non-interlocking mode in which both measuring heads are moved independently from each other, and an interlocking mode in which the measuring positions of both measuring heads are moved while matching the positions in the horizontal plane. According to the interlocking mode, measurement is performed while maintaining consistency in the horizontal plane direction on the front side and the back side of the object to be measured, as in the apparatus of the above embodiment. On the other hand, when the non-interlocking mode is used, when the position in the horizontal plane direction of the region to be measured is different between the front side and the back side of the object to be measured, they can be measured in parallel, as in the above embodiment. The measurement time is shortened compared with the case of using a simple apparatus or the above-mentioned interlocking mode.
[0034]
In this apparatus, since both the measurement heads 98 and 100 can move independently, there is a possibility that the relative positional relationship between the two measurement heads in the horizontal plane direction fluctuates due to, for example, an assembly error between the upper and lower heads. That is, even if the upper measurement head 98 and the lower measurement head 100 are moved to the same coordinate in the horizontal plane on the movement control means, the positions in the horizontal plane may actually be shifted. Although the amount is very small, when the purpose is to accurately measure the correlation between the shapes of both surfaces of the object to be measured as in the present apparatus, it causes performance degradation. Therefore, in this apparatus, a head relative position detection unit that detects the relative position of the measurement head is provided, and the control error of the movement control unit is corrected based on the detected relative position.
[0035]
FIG. 5 is a schematic diagram showing the principle of an example of the head relative position detecting means. Each of the measuring heads 98 and 100 includes a CCD camera 130 as an imaging unit and a halogen lamp 132 as a vertical epi-illumination light source. The optical axis of the vertical epi-illumination and the optical axis of the reflected light to be imaged are on the same line outside each measuring head, but these two optical axes are separated using a half mirror 134 in the measuring head. That is, a part of the light beam radiated from the halogen lamp 132 is bent at a right angle by the half mirror 134 and is directed vertically to the object to be measured. The CCD camera 130 is arranged on the same line as the light beam and behind the half mirror 134, and receives the component of the reflected light from the object to be measured that is not reflected by the half mirror 134 but goes straight.
[0036]
In order to constitute the head relative position detection means, in the above-described measurement head configuration, a mask 140 for alignment patterns composed of a transmissive liquid crystal panel is arranged on one measurement head (the lower measurement head 100 in this apparatus). Yes. The mask 140 is disposed between the halogen lamp 132 and the half mirror 134 of the lower measurement head 100. When measuring the relative position of the measurement head, a voltage signal is applied to generate an alignment pattern as shown in FIG. To do. This alignment pattern is obtained by dividing a plane into four regions by two straight lines orthogonal to each other. The brightness and darkness of the four regions are defined alternately so that the intersection of these two straight lines and by extension these two straight lines that are the center of the alignment pattern can be easily processed by image processing. The alignment pattern may be another pattern as long as the center can be easily found by image processing.
[0037]
The illumination light from the halogen lamp 132 is focused on the position of the mask 140 by the lens 142, and the lenses 144 and 146 form a light image 148 by the transmitted light of the mask 140 on the measurement direction line of the measurement head 100. The position of the alignment pattern with respect to the CCD camera 130 of the lower measurement head 100 is determined in advance by taking a light image 148 projected onto the object.
[0038]
The measurement of the relative positions of the upper and lower measurement heads in the horizontal plane is performed in a state where light can pass between the upper and lower measurement heads, with the measurement ports of both measurement heads facing each other by the movement control means. That is, the coordinates in the horizontal plane of both measuring heads are the same on the movement control means. In this state, the upper measuring head 98 moves up and down, and its imaging focus position is moved up and down to detect the optical image 148 of the mask 140. In the data processing unit, the center position of the alignment pattern in the image output from the CCD camera 130 of the upper measurement head 98 is obtained, and the difference between the center position of the lower measurement head 100 obtained in advance and the center position of the lower measurement head 100 is determined. Relative position calculation processing to be obtained as the relative position of is performed.
[0039]
By correcting the horizontal coordinates of the measurement data of the shape of the front side and the back side of the object to be measured obtained by each measuring head using the relative position, it is possible to obtain the consistency of the shape of both sides in the horizontal plane direction. it can. The measurement of the relative positions of the two measuring heads is performed, for example, in a state where the measurement object 96 is not placed on the opening 94 of the support base 92 at the start or end of the measurement in the interlock mode, or the measurement is performed on the support base 92. In addition to the opening 94 for placing the object 96, an opening for measuring the relative position may be provided so that it can be appropriately performed during shape measurement. According to the above-described head relative position detecting means, it is not necessary to bother the measurer to place the reference measurement object for alignment on the support base 92, so that the relative position measurement can be automated.
[0040]
[Embodiment 4]
FIG. 7 is a side view of the machine main body of the object shape measuring apparatus embodying the present invention. Similar to the above-described embodiment, the apparatus includes a data processing unit (not shown) and a controller unit (not shown) in addition to the machine main body.
[0041]
The machine main body includes an XY stage 154 on a support base 152. The support table 152 and the XY stage 154 have an opening 156 at the center. An object to be measured 158 is placed on the opening 156 of the XY stage 154.
[0042]
The apparatus has two upper measuring heads. The first upper measuring head is an optical measuring head 160. The second upper measuring head is a laser displacement meter 162. A transmitted illumination light source 164 used for measurement by the optical measuring head 160 is disposed at the lower part of the apparatus. The optical measurement head 160 is arranged on the upper part of the apparatus by the arm 168 from the support column 166 so as to face the transmitted illumination light source 164, while the laser displacement meter 162 is disposed by the arm 168 by the optical measurement head 160 and the transmitted illumination light source 164. Is supported by the side of the optical axis 170.
[0043]
The laser displacement meter 162 reflects the laser beam emitted from the measurement port 162A in the horizontal direction vertically downward by the half mirror 172 disposed on the optical axis 170. Then, the laser beam reflected by the measurement object 158 is reflected by the half mirror 172 and enters the laser displacement meter 162. For example, when the laser beam is inclined slightly from the vertical direction and is incident on the object 158 to be measured, the difference between the position of the reflected image of the laser beam from the object 158 and the emission position on the laser displacement meter 162 is the optical path length of the laser beam. Is proportional to This deviation can be detected from the light receiving position on the CCD line sensor, and the vertical position of the reflection point on the measurement object 158 can be measured. In addition, a laser displacement meter that detects a change in the phase difference between the emitted laser beam and the laser beam returned to the measurement port 162A by reflection and detects the vertical displacement of the reflection point of the object 158 to be measured is also considered. It is done. The laser displacement meter 162 can perform height measurement with higher accuracy than the optical measurement head 160.
[0044]
The optical measurement head 160 captures and outputs a surface image of the object to be measured from the measurement port 160 </ b> A using light that travels straight through the half mirror 172. The data processing unit processes the image and measures the surface shape. That is, although the optical measurement head 160 and the laser displacement meter 162 are arranged at different positions, the surface of the object to be measured 158 is measured from the same optical axis 172.
[0045]
In the present apparatus, a plurality of pieces of surface information of an object to be measured are collected simultaneously from the same measurement direction using a plurality of types of measurement heads. In other words, in this apparatus, the optical measurement head 160 accurately measures the shape in the horizontal plane from the image, while the laser displacement meter 162 assists the height measurement by the focus of the optical measurement head 160 and has high accuracy. Measurement is possible, and the surface shape of the object to be measured can be accurately measured both horizontally and vertically by these two measuring heads.
[0046]
As described above, the present apparatus can simultaneously measure a plurality of measurement items such as plane dimensions, height dimensions, and shapes with a plurality of types of measurement heads, thereby reducing the measurement time and the horizontal plane direction between the data of each measurement item. The position consistency is ensured. Note that the other type of measurement head used in combination with the optical measurement head may be other than a laser displacement meter, such as a touch probe.
[0047]
【The invention's effect】
According to the object shape measuring apparatus of the present invention, by providing a plurality of optical measurement heads and simultaneously measuring from a plurality of directions, the surface shape viewed from a plurality of directions can be measured in a short time, and in the plurality of directions. The effect of improving the consistency of coordinates between such measurement data is obtained. Further, according to the object shape measuring apparatus of the present invention, by measuring simultaneously from the same direction with a plurality of measurement heads of different methods, measurement of surface information of a plurality of items is performed in a short time, and the plurality of items of the plurality of items are measured. The effect of improving the consistency of coordinates between measurement data is obtained.
[Brief description of the drawings]
FIG. 1 is a side view of a machine body of an object shape measuring apparatus according to a first embodiment of the present invention.
FIG. 2 is a side view of a machine main body portion of an object shape measuring apparatus according to a second embodiment of the present invention.
FIG. 3 is a side view of a machine main body of an object shape measuring apparatus according to a third embodiment of the present invention.
FIG. 4 is a schematic perspective view showing an example of a moving means of an upper measuring head in a third embodiment.
FIG. 5 is a schematic diagram illustrating the principle of an example of a head relative position detection unit.
FIG. 6 is a schematic diagram showing an example of an alignment pattern.
FIG. 7 is a side view of a machine main body portion of an object shape measuring apparatus according to a fourth embodiment of the present invention.
FIG. 8 is a side view of a conventional object shape measuring apparatus.
[Explanation of symbols]
52,152 Support base, 54,154,110 XY stage, 60,98 Upper measurement head, 62,100 Lower measurement head, 70 Side measurement head, 72, 96,158 Object to be measured, 90 Lower housing, 92 Support base, 104, 106 Ball screw, 130 CCD camera, 132 Halogen lamp, 134, 172 half mirror, 140 Mask for alignment pattern, 160 Optical measuring head, 162 Laser displacement meter, 164 Transmitted illumination light source.

Claims (4)

In the object shape measuring apparatus for measuring the surface shape of the measurement object viewed from an arbitrary measurement direction by performing image processing on image information output from the optical measurement head for imaging the measurement object,
A plurality of optical measuring heads are provided, and the shape of the object to be measured is simultaneously measured from a plurality of the measuring directions;
The plurality of optical measurement heads include first and second optical measurement heads whose measurement directions are opposite to each other, and
Head moving means for independently moving the first and second optical measuring heads in a plane direction perpendicular to the measuring direction;
An object shape measuring apparatus comprising head relative position detecting means for detecting a relative position between the first optical measuring head and the second optical measuring head in the vertical plane direction. Head moving means for independently moving the first and second optical measuring heads in a plane direction perpendicular to the measuring direction;
A mode in which the first and second optical measuring heads are moved independently of each other to scan and measure both sides of the object to be measured; and both the first and second optical measuring heads are in the vertical direction. And a movement control means for controlling the head moving means in accordance with any one mode of scanning and measuring both sides of the object to be measured while matching the measurement positions in the plane direction. The object shape measuring apparatus according to claim 1, wherein: The first and second optical measurement heads each include an illuminator that emits focused light and a sensor that detects that the light is focused on the surface of the object to be measured;
The head relative position detection means includes
An optical image of the alignment pattern is detected by means for projecting an alignment pattern provided in the irradiator of the first optical measurement head and the sensor of the second optical measurement head. And calculating and outputting a relative position between the first optical measurement head and the second optical measurement head from the position of the optical image,
The object shape measuring apparatus according to claim 1 . The first optical measurement head includes an illuminator that illuminates the object to be measured;
The irradiator is used as transmitted illumination in the measurement by the second optical measuring head;
The object shape measuring apparatus according to claim 1 .

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