JP2008164571A - Measurement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that in the moire method of conventional technology for obtaining the contour lines from the moire pattern, it is necessary to perform complicated operations, and moreover to obtain at once the contour lines of a body having level difference, errors are generated depending on the level difference. <P>SOLUTION: The measurement device is provided with: a light transmission part for transmitting the light to a first direction; a rotation part for making an object to be measured and a light transmission part rotate relatively while centering the axis perpendicularly intersecting with the first direction; a detection part for detecting the light reflected by the object to be measured; and a shape measurement part for measuring the shape of the object to be measured based on the detection results of the detection part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a measuring apparatus for measuring a three-dimensional shape of an object.

Conventionally, a moire method is known as a method for measuring the three-dimensional shape of an object using contour lines. The moire method is a method of obtaining a three-dimensional shape of an object by projecting a fringe pattern from an illumination device onto an object and obtaining contour lines along the object shape from a moire pattern observed through another stripe pattern ( For example, see Patent Document 1).
JP-A-10-206130

The moire method according to the prior art has to perform a complicated calculation in order to obtain a contour line from a moire pattern. Furthermore, since the contour lines of an object having a height difference are obtained at a time, there is a problem that an error occurs due to the height difference of the object.
An object of the present invention is to provide a measuring apparatus that can perform high-accuracy measurement with few errors without performing complicated calculations with a simple configuration.

  A measuring apparatus according to the present invention is a measuring apparatus that measures the shape of a three-dimensional object to be measured, and a light transmitting unit that transmits light in a first direction, and an axis that is substantially orthogonal to the first direction. A rotating unit that relatively rotates the object to be measured and the light transmitting unit around the object, a detection unit that detects the light reflected by the object to be measured, and a detection result of the detection unit, And a shape measuring unit that measures the shape of the object to be measured.

Furthermore, the apparatus further includes a moving unit that relatively moves the object to be measured and the light transmitting unit in a direction substantially orthogonal to the first direction, and the shape measuring unit includes the object to be measured and the light transmitting unit. The three-dimensional shape of the object to be measured is measured based on the detection result of the detection unit when the relative position is changed.
In particular, the rotating unit fixes the light transmitting unit and rotates the object to be measured.

The moving unit may move the light transmitting unit while fixing the object to be measured.
Alternatively, the moving unit fixes the light transmitting unit and moves the object to be measured.
Alternatively, the moving unit fixes the object to be measured and moves the light transmitting unit.

  Alternatively, the moving unit fixes the light transmitting unit and moves the object to be measured.

  According to the present invention, it is possible to measure the three-dimensional shape of an object with high accuracy without performing complicated calculations with a simple configuration.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram of a three-dimensional shape measuring apparatus 101 according to the first embodiment. The three-dimensional shape measuring apparatus 101 is an apparatus that constructs a three-dimensional shape of an object by measuring the outer shape of a three-dimensional object at every predetermined height to obtain contour lines and combining the obtained contour lines. Unit 102, light projecting / moving unit 103, light projecting / fixing unit 104, rotation stage 105, stage fixing unit 106, measurement platform 107 on which the object 108 is to be measured, imaging unit 109, and image processing unit 110. And a personal computer 111.

  The light projecting unit 102 projects an image of light serving as a mark on the measurement object 108. An image of any shape may be projected as a mark, but a basic shape such as a circle that is easy to recognize in an image captured by the imaging unit 109 is preferable. Further, since the shape of the object to be measured 108 is various, it is desirable that the projected image is focused as much as possible even if the distance to the projection position on the object to be measured 108 changes. That is, it is preferable that the depth of focus on the projected image side is deep, and it is advantageous that the NA (Numerical Aperture) of the optical system is small. For these reasons, it is preferable to use a laser beam that does not require the preparation of a special optical system, and the apparatus configuration is compact.

The light projecting / moving unit 103 and the light projecting / fixing unit 104 move the light projecting unit 102 fixed to the upper end of the light projecting / moving unit 103 up and down based on control from the image processing unit 110.
The rotation stage 105 and the stage fixing unit 106 rotate the rotation stage 105 on the stage fixing unit 106 based on control from the image processing unit 110. In other words, the light projecting unit 102 has the same height around the object 108 to be measured placed on the measurement table 107 via the light projecting fixing unit 104 and the light projecting / moving unit 103 fixed on the rotary stage 105. Rotate with.

  For example, the light 151 emitted from the light projecting unit 102 in a state where the light projecting / moving unit 103 is moved to a certain height hits the object to be measured 108 to form a point image. The point image projected on the DUT 108 is formed on the light receiving surface of the imaging unit 109. Although not shown in the drawing, an imaging optical system is disposed on the object 108 side of the imaging unit 109 so that an image is formed on the light receiving surface of the imaging unit 109 in the moving range of the object 108 to be measured. Is adjusted in advance.

The light imaged on the light receiving surface of the imaging unit 109 is converted into image data and output to the image processing unit 110 via the cable 112.
The image processing unit 110 receives the image data from the imaging unit 109 and sends a command to the light projecting fixing unit 104 connected via the cable 113, so that the light projecting moving unit 103 on which the light projecting unit 102 is mounted is captured by the imaging unit. Move up and down at a predetermined pitch in the 109 direction. That is, the relative position between the DUT 108 and the light projecting unit 102 is changed. Then, the light projection moving unit 103 is moved up and down at a predetermined pitch, and image data is input from the imaging unit 109 at every predetermined height of the object to be measured 108. At this time, at every predetermined height, the image processing unit 110 sends a command to the stage fixing unit 106 via the cable 114 to rotate the rotary stage 105 once at a predetermined rotation pitch. The image processing unit 110 inputs image data from the imaging unit 109 at every predetermined angle of the rotary stage 105. In other words, the imaging unit 109 captures an image at a predetermined angle and outputs the image data to the image processing unit 110 while the rotation stage 105 rotates once. The image processing unit 110 processes the input image data for one rotation, and obtains the outer shape of the DUT 108 at a predetermined height. The method for obtaining the outer shape will be described in detail later.

Here, the upper surface of the measurement table 107 on which the object 108 to be measured 108 is placed, the upper surface of the rotary stage 105, and the surface on which the light projecting unit 102 rotates are installed so as to be parallel to each other. The trajectory of the light that the light projecting unit 102 makes one turn at the same height and projects onto the measurement object 108 indicates the contour lines of the measurement object 108.
Next, the measurement flow of the three-dimensional shape measuring apparatus 101 will be described in detail with reference to the flowchart of FIG.
(Step S201) First, the object to be measured 108 is set on the measurement table 107.
(Step S202) Next, measurement specifications such as a measurement range (movement range) and a measurement pitch (movement pitch) of the light projecting movement unit 103 are input from the personal computer 111. The measurement specification input by the personal computer 111 is output to the image processing unit 110 via the cable 115, and the image processing unit 110 moves the light projecting moving unit 103 to the initial position via the cable 113 to the light projecting fixing unit 104. Command. For example, the light projection moving unit 103 is moved to a position where the light of the light projecting unit 102 is projected to a height h1 from the upper surface of the measurement table 107 in FIG. At the same time, the image processing unit 110 instructs the stage fixing unit 106 to move the rotary stage 105 to the initial position. Thereafter, the rotating stage 105 returns to the initial position every time it makes one rotation.
(Step S <b> 203) Light is projected from the light projecting unit 102 to the object 108 to be measured at the current position of the light projecting / moving unit 103.
(Step S <b> 204) An image of light projected on the DUT 108 is captured by the imaging unit 109 and output to the image processing unit 110.
(Step S205) The rotary stage 105 is rotated by a predetermined angle from the current position.
(Step S206) It is determined whether or not the rotation stage 105 has made one rotation, that is, whether or not the rotation stage 105 has returned to the initial position. If the rotation stage 105 has not made one rotation, the process returns to step S203, and if one rotation has been completed, the process proceeds to step S207.
(Step S207) When the rotation stage 105 makes one rotation, the image processing unit 110 synthesizes the locus of the pointer from the image data for one rotation, and obtains the outer shape of the object to be measured 108 at that height, that is, the contour line. For example, FIG. 3B shows a state in which the images when the rotary stage 105 is rotated once at the height of h1 in FIG. 3A are combined, and each point is a light projection taken at a predetermined angle. The point of the light which the part 102 projected is shown, and the line which connected these points turns into the contour line g1 in the height.
(Step S208) It is determined whether the measurement is completed according to the measurement specification. For example, if the light projecting / moving unit 103 has not reached the end position of the movement range, the process proceeds to step S209, and if it has reached the end position, the process proceeds to step S210.
(Step S209) The light projection moving unit 103 is moved to the next measurement position according to the set measurement pitch. For example, the light projecting / moving unit 103 is moved to a position where light from the light projecting unit 102 is projected to a height h2 from the upper surface of the measurement table 107 in FIG. After the movement, the process returns to step S203 again, and a contour line at that height is obtained. For example, as described in FIG. 3B, the contour line g2 at the height h2 of the DUT 108 placed on the measurement table 107 is obtained in FIG. A contour line g3 at h3 is obtained.
(Step S210) When the moving stage 110 reaches the end position of the moving range and ends the measurement, the image processing unit 110 combines the contour lines for each height obtained in Step S207 to create three-dimensional shape data. . For example, as shown in FIG. 3A, in step S207, the contour lines g1, g2, and g3 at the positions of the heights h1, h2, and h3 of the object 108 placed on the measuring table 107 are obtained. Therefore, these contour lines g1, g2, and g3 are synthesized to obtain a contour image as shown in FIG.
(Step S211) Three-dimensional shape data is obtained by combining the contour image obtained in Step S210 with height information. When this is displayed three-dimensionally, for example, a three-dimensional shape 108a of the object 108 to be measured as shown in FIG. In the description of this flowchart, only the three contour lines g1, g2, and g3 have been described for the sake of clarity. However, actually, as shown by the dotted lines in FIG. By moving the moving unit 103 up and down to obtain contour lines at each height, a highly accurate three-dimensional shape 108a of the object 108 to be measured can be constructed.
(Step S212) If necessary, the personal computer 111 operates the keyboard or mouse to specify an arbitrary position of the device 108 displayed on the screen, and the device under test received from the image processing unit 110. The size and length of each part are obtained from the three-dimensional shape data 108 and displayed.
(Step S213) All measurements are finished.

  In this way, the light projection moving unit 103 is moved up and down at a predetermined pitch, and at the same time, the rotary stage 105 is rotated to extract the outer shape of the portion where the light hits the object to be measured 108, and these are extracted for each predetermined position. By combining them as contour lines, the three-dimensional shape data of the object to be measured 108 can be measured. The measured three-dimensional shape data of the measured object 108 is sent to the personal computer 111 via the cable 115, and the personal computer 111 can display the three-dimensional shape of the measured object 108.

  In this embodiment, the image processing unit 110 that performs image processing and the personal computer 111 that displays the operation of the entire three-dimensional shape measurement apparatus 101 and the display of measurement results are separately provided. The hardware and software may be built in. Or, conversely, an operation unit or a display unit may be provided in the image processing unit 110 to be a control unit dedicated to the three-dimensional shape measuring apparatus 101.

  As described above, the three-dimensional shape measuring apparatus 101 according to the present embodiment measures the outer shape for each predetermined height of the three-dimensional object to obtain contour lines, and measures the predetermined position measured while changing the height. Since it is possible to construct a three-dimensional shape of an object by synthesizing contour lines, it is possible to provide a highly accurate three-dimensional shape measuring apparatus and method therefor with a simple structure and without performing complicated calculations, it can. In particular, the moire method that obtains all the contour lines at once has a problem that the error becomes large due to the difference in height of the object, but the 3D shape measuring apparatus and the measuring method according to the present embodiment obtain an image for each contour line. Therefore, highly accurate measurement is possible regardless of the height difference of the object.

(Second Embodiment)
Next, a three-dimensional shape measuring apparatus 201 according to the second embodiment will be described with reference to FIG. The three-dimensional shape measuring apparatus 201 has the same basic configuration as that of the three-dimensional shape measuring apparatus 101 of the first embodiment, but does not have the light projection fixing unit 104 and the light projection moving unit 103, and has a predetermined rotation stage 105. A fixing portion 204 for fixing the light projecting portion 102 is provided at the position. Furthermore, instead of the measurement table 107 on which the object to be measured 108 is placed, a movable measurement table 202 and a fixed measurement table 203 for moving the movement measurement table 202 up and down by an instruction from the image processing unit 205 are provided.

  Further, the image processing unit 205 performs basically the same image processing as the image processing unit 110 of the first embodiment, but the process of the light projecting and moving unit 103 is replaced with the movement measurement table 202 in the flowchart of FIG. . That is, in the first embodiment, the height of the light projected on the measurement object 108 is varied by moving the light projecting unit 102 attached to the tip of the light projecting moving unit 103 up and down. In the embodiment, the height of light projected on the measurement object 108 is varied by moving the measurement object 108 placed on the movable measurement table 202 up and down.

  Except for the above points, as in the first embodiment, the outer shape of the portion where light hits the object to be measured 108 is extracted, and these are synthesized as contour lines for each predetermined position, thereby the object 108 to be measured. 3D shape data is measured. The measured three-dimensional shape data of the measured object 108 is sent to the personal computer 111 via the cable 115, and the personal computer 111 displays the three-dimensional shape of the measured object 108.

  As described above, the three-dimensional shape measuring apparatus 201 according to the present embodiment obtains contour lines by measuring the outer shape for each predetermined height of the three-dimensional object, and determines the contour for each predetermined position measured while varying the height. Since it is possible to construct a three-dimensional shape of an object by synthesizing contour lines, it is possible to provide a highly accurate three-dimensional shape measuring apparatus and method therefor with a simple structure and without performing complicated calculations, it can.

(Third embodiment)
Next, a three-dimensional shape measuring apparatus 301 according to the third embodiment will be described with reference to FIG. The three-dimensional shape measuring apparatus 301 has the same basic configuration as the three-dimensional shape measuring apparatus 101 of the first embodiment, but does not include the stage fixing unit 106 and the rotating stage 105, and the light projection fixing unit 104 is a fixed stage. 302 is attached. Further, the measurement table 107 on which the object to be measured 108 is placed is fixed to the measurement rotation stage 303, and the measurement rotation stage 303 is rotated on the measurement stage fixing unit 304 in response to an instruction from the image processing unit 305.

  The image processing unit 305 performs basically the same image processing as the image processing unit 110 of the first embodiment, but the processing of the rotary stage 105 is replaced with the processing of the measurement rotary stage 303 in the flowchart of FIG. . In other words, in the first embodiment, the light projecting unit 102 attached to the rotary stage 105 via the light projecting fixing unit 104 and the light projecting moving unit 103 rotates around the object 108 to be measured. Although the contour line of the object 108 is obtained, in this embodiment, the contour line of the object 108 to be measured is obtained by rotating the object 108 placed on the measurement table 107 on the measurement rotation stage 303.

  Except for the above points, as in the first embodiment, the outer shape of the portion of the object to be measured 108 that is exposed to light is extracted, and these are combined as contour lines for each predetermined height to be measured. The three-dimensional shape data of the object 108 is measured. The measured three-dimensional shape data of the measured object 108 is sent to the personal computer 111 via the cable 115, and the personal computer 111 displays the three-dimensional shape of the measured object 108.

  As described above, the three-dimensional shape measuring apparatus 301 according to the present embodiment measures the outer shape for each predetermined height of the three-dimensional object to obtain the contour line, and measures the predetermined position measured while varying the height. Since it is possible to construct a three-dimensional shape of an object by synthesizing contour lines, it is possible to provide a highly accurate three-dimensional shape measuring apparatus and method therefor with a simple structure and without performing complicated calculations, it can.

  In the first embodiment, the light projecting unit 102 is moved up and down and rotated. In the second embodiment, the height of the light projecting unit 102 is fixed and rotated, and the object 108 is moved up and down. The structure was moved. In the third embodiment, the light projecting unit 102 is moved up and down and the measured object 108 is rotated. In addition to this, the second and third embodiments can be combined to realize a structure in which the height and rotation position of the light projecting unit 102 are fixed, and the measured object 108 is moved up and down and rotated. be able to.

It is a lineblock diagram of three-dimensional shape measuring device 101 concerning a 1st embodiment. 3 is a flowchart showing a measurement procedure of the three-dimensional shape measuring apparatus 101. It is an auxiliary figure for explaining construction of a three-dimensional shape. It is a block diagram of the three-dimensional shape measuring apparatus 201 which concerns on 2nd Embodiment. It is a block diagram of the three-dimensional shape measuring apparatus 301 which concerns on 3rd Embodiment.

Explanation of symbols

101, 201, 301 ... Three-dimensional shape measuring apparatus; 102 ... Projection unit; 103 ... Projection movement unit; 104 ... Projection fixing unit; 105 ... Rotation stage; Stage fixing unit 107 107 Measuring table 108 Object to be measured 109 Imaging unit 110, 205, 305 Image processing unit 111 Personal computer 202 Moving Measurement stage; 203 ... Fixed measurement stage; 204 ... Fixed part; 302 ... Fixed stage; 303 ... Measurement rotary stage; 304 ... Measurement stage fixed part

Claims (7)

A measuring device for measuring the shape of a three-dimensional object to be measured,
A light transmitting section for transmitting light in a first direction;
A rotating unit that relatively rotates the object to be measured and the light transmitting unit about an axis substantially orthogonal to the first direction;
A detector for detecting the light reflected by the object to be measured;
A measuring apparatus comprising: a shape measuring unit that measures the shape of the object to be measured based on a detection result of the detecting unit. The measuring apparatus according to claim 1,
A moving unit that relatively moves the object to be measured and the light transmitting unit in a direction substantially orthogonal to the first direction;
The shape measuring unit measures a three-dimensional shape of the measured object based on a detection result of the detecting unit when a relative position between the measured object and the light transmitting unit is changed. Measuring device. The measuring apparatus according to claim 2,
The rotating unit fixes the light transmitting unit and rotates the object to be measured. The measuring apparatus according to claim 2,
The moving unit fixes the object to be measured and moves the light transmitting unit. The measuring apparatus according to claim 2,
The moving device fixes the light transmitting unit and moves the object to be measured. The measuring device according to claim 3,
The moving unit fixes the object to be measured and moves the light transmitting unit. The measuring device according to claim 3,
The moving device fixes the light transmitting unit and moves the object to be measured.

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