JP2008164573A - Measurement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the moire method in the conventional technique is necessary to complicated operation for obtaining the contour line from the moire pattern. <P>SOLUTION: The measurement device for measuring the shape of the object comprises: a liquid maintaining part for maintaining the prescribed amount of liquid for sinking the measurement object; a light source for irradiating the object and the liquid with the light; a detector for detecting the boundary line of the object and the liquid; and a shape measurement part for measuring the shape of the object based on the detection result 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. In addition, a dedicated illumination device is required, and the configuration is complicated, resulting in an increase in device cost.
An object of the present invention is to provide a measuring apparatus capable of measuring a three-dimensional shape of an object with a simple configuration using a liquid.

A measuring apparatus according to the present invention is a measuring apparatus for measuring the shape of an object to be measured, and includes a liquid holding unit that holds a predetermined amount of liquid that sinks the object to be measured, and light to the object to be measured and the liquid. An illumination light source, a detection unit that detects a boundary line between the measurement object and the liquid, and a shape measurement unit that measures the shape of the measurement object based on a detection result of the detection unit. And
Furthermore, the moving part which moves the said to-be-measured object and the said liquid holding part relatively to the direction of the said detection part is further provided, The said shape measurement part changes the relative position of the said to-be-measured object and the said liquid holding part. The three-dimensional shape of the object to be measured is measured based on the detection result of the detection unit at that time.

Further, a liquid management unit that manages a liquid surface position of the liquid held by the liquid holding unit is provided.
In particular, the liquid management unit is characterized in that the liquid level position of the liquid held by the liquid holding unit is kept constant.
Alternatively, the liquid management unit detects a liquid level position of the liquid held by the liquid holding unit, and outputs the liquid level position to the shape measuring unit.

Alternatively, the liquid management unit includes an autofocus unit disposed above and parallel to the liquid level of the liquid holding unit, and the autofocus unit corresponds to the operation of the moving unit. In this case, the liquid level position is detected and the liquid level position is output to the shape measuring unit.
In particular, the liquid is a colored liquid.

  The measuring apparatus according to the present invention can obtain the outer shape of an object with a simple configuration using a liquid, and can measure the three-dimensional shape of the object to be measured without performing complicated calculations.

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 for constructing a three-dimensional shape of an object by measuring the outer shape at every predetermined height of a three-dimensional object to be measured to obtain contour lines and synthesizing the obtained contour lines. Light source 102, water tank 103, liquid 104, Z-axis stage main body 105 and moving stage 106, measured object 107 fixed on moving stage 106, imaging unit 108, image processing unit 109, liquid It is composed of a face meter 110 and a personal computer 111.

FIGS. 1A and 1B are views showing a state when the Z-axis stage main body 105 and the moving stage 106 are operated. FIG. 1B is a view showing the state of the object 107 to be measured by raising the moving stage 106. When measuring the outer shape of the lower position, FIG. 4A shows the case of measuring the outer shape of the measured object 107 at a higher position by lowering the moving stage 106.
The light emitted from the light source 102 on the upper surface of the water tank 103 irradiates the liquid surface of the liquid 104 in the water tank 103 and the measurement object 107 protruding from the liquid surface. The liquid surface of the liquid 104 and the light reflected by the measurement object 107 protruding from the liquid surface are imaged on a light receiving surface (not shown) of the imaging unit 108 as indicated by a dotted line 151.

The optical system shown in FIG. 1 is configured as shown in FIG. In FIG. 2, for example, the light reflected by the boundary between the liquid surface of the liquid 104 and the object 107 to be measured passes through the objective lens 116, the imaging diaphragm 117, and the imaging lens 118 as indicated by the dotted line. An image is formed as a boundary line on the light receiving surface of the imaging unit 108. The same reference numerals as those in FIG.
The light imaged on the light receiving surface of the imaging unit 108 in FIG. 1 is converted into an image signal and output to the image processing unit 109 via the cable 112.

  Here, the light receiving surface of the imaging unit 108 and the liquid 104 are optically conjugate, and the boundary between the object 107 to be measured, which is a part of the liquid surface, is also conjugate, and these two places are in focus. It has become. Although the focus shift is predicted depending on the height of the object 107 to be measured, the object 107 is measured by reducing the NA (Numerical Aperture) of the aperture stop 117 in FIG. The focus shift can be eliminated within the fluctuation range of the height.

On the other hand, the measurement accuracy can be improved by increasing the aperture (NA) of the aperture stop 117.
The liquid 104 in the water tank 103 has a predetermined amount in which the measured object 107 fixed to the moving stage 106 is sufficiently submerged, and when the moving stage 106 is raised, the measured object 107 protrudes on the water surface of the liquid 104. In addition, since the volume of the part under the water surface of the object 107 to be measured changes depending on the position of the moving stage 106, the water surface position of the liquid 104 also moves up and down.

  The liquid level meter 110 detects the water surface position and outputs it to the image processing unit 109. The liquid level gauge, for example, applies two conductors in parallel and perpendicularly to the inside of the water tank 103, and measures the position of the portion immersed in the liquid 104 and the resistance between the two conductors in advance. Thus, the position of the liquid level can be detected from the change in resistance. In addition, a capacitive liquid level sensor can be used in the outer wall of the water tank 103 or in the liquid 104.

  The image processing unit 109 receives the image data imaged on the light receiving surface of the imaging unit 108 and sends a command to the Z-axis stage main body 105 connected via the cable 113 to move the object 107 to be measured. The stage 106 is moved up and down at a predetermined pitch in the direction of the imaging unit 108. That is, the relative position between the DUT 107 and the liquid surface of the liquid 104 is changed. Then, image data is input from the imaging unit 108 for each predetermined position of the moving stage 106, and at the same time, the liquid level position is also input from the liquid level meter 110. Furthermore, the input image data is processed to extract an outer shape (corresponding to a contour line) of the boundary portion between the DUT 107 and the liquid surface of the liquid 104 at a predetermined position. For example, the upper surface position of the moving stage 106 at the time of measurement is Z1 from the bottom surface of the Z-axis stage main body 105 (bottom of the water tank 103), and the height from the bottom of the water tank 103 detected by the liquid level gauge 110 is L1. If so, the height of the DUT 107 at the time of measurement can be obtained by (L1-Z1). In this way, the contour line for each height of the object 107 to be measured is obtained, and the three-dimensional shape data of the object 107 to be measured can be measured by combining these contour lines. The three-dimensional shape data measured by the image processing unit 109 is output to the personal computer 111 via the cable 115, and the three-dimensional shape is displayed on the screen of the personal computer 111.

Next, the measurement flow of the three-dimensional shape measuring apparatus 101 will be described with reference to the flowchart of FIG.
(Step S201) First, the DUT 107 is set on the moving stage 106.
(Step S202) Next, measurement specifications such as a measurement range (movement range) and a measurement pitch (movement pitch) of the moving stage 106 are input from the personal computer 111. The measurement specification input by the personal computer 111 is output to the image processing unit 109 via the cable 115, and the image processing unit 109 moves the moving stage 106 to the initial position with respect to the Z-axis stage main body 105 via the cable 113. To do. For example, the moving stage 106 is moved to the lowest point as shown in FIG.
(Step S203) Light is emitted from the light source 102 at the current position of the moving stage 106, and an image is captured by the imaging unit 108.
(Step S <b> 204) The image processing unit 109 inputs an image received by the light receiving surface of the imaging unit 108 via the cable 112, and extracts a boundary line between the DUT 107 and the liquid surface of the liquid 104. At the same time, the liquid level position of the liquid 104 is input from the liquid level meter 110, the height of the object 107 to be measured is obtained as described above, and stored in association with the extracted boundary line image.
(Step S205) It is determined whether the measurement is completed according to the measurement specification. For example, if the moving stage 106 has not reached the end position of the moving range, the process proceeds to step S206, and if it has reached the end position, the process proceeds to step S207.
(Step S206) The moving stage 106 is moved to the next measurement position according to the set measurement pitch, and the process returns to Step S203 to perform measurement at the position.
(Step S207) When the moving stage 106 reaches the end position of the moving range and ends the measurement, the measured object 107 is obtained from the boundary line image and the height data of the measured object 107 stored in Step S204. The contour lines for each height are obtained, and these contour lines are synthesized to create three-dimensional shape data.

  Here, a method of creating three-dimensional shape data will be described with reference to FIG. FIG. 2A shows contour lines g1, g2 and g3 of the object 107 to be measured placed on the moving stage 106, which are located at heights h1, h2 and h3 from the upper surface of the moving stage 106. FIG. The heights h1, h2, and h3 are the heights of the measured object 107 calculated from the liquid surface position of the liquid 104 detected by the liquid level gauge 110 and the upper surface position of the moving stage 106, as described above. means.

  For example, when the moving stage 106 is moved up and down and the liquid level of the liquid 104 comes to the height h1 portion of the object 107 to be measured, an image photographed by the imaging unit 108 becomes a contour line g1 as shown in FIG. . Actually, since the light receiving unit of the imaging unit 108 is composed of pixels arranged in a matrix, it is obtained as a number of points as shown in FIG. Similarly, when an image is taken by the imaging unit 108 when the liquid level of the liquid 104 comes to the height h2, a contour line g2 as shown in FIG. 4C is obtained. Further, when the imaging unit 108 takes an image when the liquid level of the liquid 104 comes to the height h3, a contour line g3 as shown in FIG. 4D is obtained. When these contour lines g1, g2, and g3 are synthesized, the result is as shown in FIG. 4 (e). Further, when the three-dimensional display is performed together with the height information of the heights h1, h2, and h3, as shown in FIG. 4 (f). Three-dimensional shape data of the DUT 107 is obtained. Although the description has been made using three contour lines here, in practice, the three-dimensional shape 107a of the object 107 to be measured with high accuracy can be obtained by synthesizing a large number of contour lines having a narrow measurement pitch as shown by dotted lines in FIG. Can be built.

Returning to the flowchart of FIG.
(Step S208) The three-dimensional shape data created by the image processing unit 109 is output to the personal computer 111 through the cable 115 and displayed on the screen of the personal computer 111.
(Step S209) If necessary, the personal computer 111 operates the keyboard or mouse to specify an arbitrary position of the device 107 displayed on the screen, and the device under test received from the image processing unit 109. The size and length are obtained from the three-dimensional shape data 107 and displayed.
(Step S210) All measurements are finished.

In this way, the outer shape of the portion where the light hits the object to be measured is extracted while moving the moving stage 106 up and down at a predetermined pitch, and at the same time, the liquid level position is detected by the liquid level gauge 110 to measure the object 107 to be measured. The three-dimensional shape of the object to be measured 107 can be measured by obtaining the heights of these and combining them for each height.
In this embodiment, the image processing unit 109 that performs image processing and the personal computer 111 that displays the operation of the entire three-dimensional shape measuring apparatus 101 and the display of measurement results are provided separately. The hardware and software may be built in. Alternatively, conversely, an operation unit and a display unit may be provided in the image processing unit 109 so as to be a dedicated control unit for the three-dimensional shape measuring apparatus 101.

  In this embodiment, the liquid level meter 110 is provided to detect the liquid level position of the liquid 104. For example, an infrared autofocus (AF) unit is installed to measure the distance to the liquid level. And the height to the liquid level of the to-be-measured object 107 can be calculated | required by subtracting the distance to the liquid level measured from the distance from the bottom of the water tank 103 to AF part. Alternatively, the liquid level gauge 110 may be omitted by increasing the size of the water tank 103 to be negligible compared to the size of the object 107 to be measured.

  Alternatively, an inlet / outlet pump is provided so that the liquid surface position of the liquid 104 is constant, and the liquid surface position of the liquid 104 is constant regardless of the volume of the portion in which the object 107 is submerged in the liquid 104. It does not matter if it becomes. Conversely, the movable stage 106 can be a fixed stage, the liquid level can be controlled by varying the amount of the liquid 104 with an inlet / outlet pump, and the same level can be measured by moving the liquid level up and down at a predetermined pitch. It is.

  Further, in the present embodiment, the case is shown in which the object to be measured 107 protrudes from the liquid 104 even when the moving stage 106 is lowered to the lowest point. However, the object to be measured is shown when the moving stage 106 is lowered to the lowest point. 107 may sink in the liquid 104. In that case, the moving stage 106 may be gradually raised from the lowest point to detect that a part of the object 107 to be measured protrudes from the liquid 104, and that part may be the upper end of the object 107 to be measured.

  Furthermore, in the present embodiment, the color of the liquid 104 has not been specifically described. However, if the liquid 104 is colored, it is easy to extract the boundary with the object 107 to be measured. For example, in FIGS. 4B, 4 </ b> C, and 4 </ b> D, when the color of the object 107 to be measured is a color that does not include red, the color of the liquid 104 is changed to red so that the red color and the other colors are obtained. It is only necessary to extract the boundary part.

  As described above, the three-dimensional shape measuring apparatus 101 according to the present embodiment measures the outer shape at every predetermined height of the three-dimensional object 107 to obtain contour lines, and measures the height while changing the height. Since the three-dimensional shape of the object can be constructed by synthesizing the contour lines of each length, it is possible to provide a highly accurate three-dimensional shape measuring apparatus and method thereof without performing complicated calculations with a simple configuration. it can.

It is a lineblock diagram of three-dimensional shape measuring device 101 concerning a 1st embodiment. 3 is an auxiliary diagram showing an optical system of the three-dimensional shape measuring apparatus 101. FIG. 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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Three-dimensional shape measuring apparatus; 102 ... Light source; 103 ... Water tank; 104 ... Liquid; 105 ... Z-axis stage main body; 106 ... Moving stage; 108; imaging unit; 109 ... image processing unit; 110 ... liquid level gauge; 111 ... personal computer

Claims (7)

A measuring device for measuring the shape of an object to be measured,
A liquid holding unit for holding a predetermined amount of liquid that sinks the object to be measured;
A light source for irradiating light to the object to be measured and the liquid;
A detection unit for detecting a boundary line between the object to be measured and the liquid;
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 liquid holding unit in the direction of the detection unit;
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 liquid holding unit is changed. Measuring device. The measuring apparatus according to claim 1 or 2,
A measuring apparatus comprising: a liquid management unit that manages a liquid surface position of the liquid held by the liquid holding unit. The measuring device according to claim 3,
The liquid management unit keeps a liquid surface position of the liquid held by the liquid holding unit constant. The measuring device according to claim 3,
The liquid management unit detects a liquid level position of the liquid held by the liquid holding unit, and outputs the liquid level position to the shape measuring unit. The measuring device according to claim 3,
The liquid management unit has an autofocus unit that is located above the liquid level of the liquid holding unit and is arranged in parallel with the liquid level,
The autofocus unit detects a liquid level position that changes according to the operation of the moving unit, and outputs the liquid level position to the shape measuring unit. In the measuring device according to any one of claims 1 to 6,
A measuring apparatus, wherein the liquid is a colored liquid.

Images