JP4034903B2 - measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a measuring apparatus that captures an image of an object to be measured held horizontally with a camera and measures the dimensions of the object to be measured from the coordinates of the camera.
[0002]
[Prior art]
As a conventional measuring device of this type, for example, a two-dimensional measurement that measures a dimension of an electrode pattern or the like printed on a measured object by imaging a flat measured object set on a horizontal table from above with a camera The device is known. The camera is held movably in the XY direction parallel to the table. That is, the two-dimensional measuring apparatus includes a horizontal upper side positioned above the table, a lower side positioned below the table and parallel to the upper side, and a pair of vertical lines connecting both ends of the upper side and the lower side. A gate-shaped frame composed of side edges is provided, and a pair of guide rails parallel to each other are laid along the Y direction below the table. The movable elements that reciprocate in the Y direction along the guide rails hold both ends of the lower side, a feed screw is disposed in parallel to the guide rail, and the lower part of the portal frame has a substantially central portion. A nut that is screwed onto the feed screw is secured. A linear scale is arranged in parallel to the guide rail, and the scale in the Y direction of the portal frame is detected by reading the scale of the linear scale with a head amplifier attached to the bottom of the portal frame near the nut. ing.
[0003]
A guide rail, a feed screw, and a linear scale are arranged along the X direction on the upper side of the portal frame. A camera holder that can reciprocate in the X direction is provided to hold the camera in the camera holder. Yes.
[0004]
[Problems to be solved by the invention]
The moving mass in the X direction including the camera and the camera holder is relatively small, but the moving mass in the Y direction including the moving mass in the X direction and the portal frame sized to straddle the drive motor and the table in the X direction is extremely large. Become. The driving force in the Y direction is transmitted from the driving motor to the feed screw, and all the driving force acts on the lower side of the portal frame through the nut. Since all the driving force in the Y direction is concentrated on the nut, the lower side to which the nut is attached bends in the moving direction. On the other hand, since the head amplifier for detecting the coordinates in the Y direction is attached in the vicinity of the nut, if the lower side is bent, the mounting portion of the head amplifier is also bent, so that the relative position between the head amplifier and the camera changes. For this reason, even if the camera is stopped at the same position, the detected Y coordinate is different between when the camera is moved from the forward direction and stopped, and when it is moved from the backward direction and stopped, a measurement error occurs.
[0005]
In view of the above problems, an object of the present invention is to provide a measuring apparatus that does not cause an error in the detected value of the Y coordinate.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention has a flat table on which an object to be measured is placed, a horizontal upper side that holds a camera that is located above the table and images the object to be measured, and a table A gate-shaped frame consisting of a lower side parallel to the upper side and a pair of vertical sides connecting both ends of the upper side and the lower side, and a parallel to the lower side of the table A mover that reciprocates along a pair of guide rails holds both ends of the lower side, and a nut that is screwed into a feed screw arranged parallel to the guide rail and drives the portal frame along the guide rail. In the measuring device that is attached to the approximate center of the lower side and detects the camera coordinates by detecting the scale of the linear scale arranged in parallel with the guide rail with a head amplifier that moves with the portal frame, Bridged the support member so as not to contact the frame, characterized in that the mounting head amplifier to the support member.
[0007]
Since the supporting member for mounting the head amplifier is installed so as not to contact the portal frame, even if the portal frame is deformed, the deformation does not affect the supporting member. Therefore, the relative position of the head amplifier and the camera Does not change.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1, reference numeral 1 schematically shows a main part of the two-dimensional measuring apparatus, and a pair of guide rails 2 that are long in the front-rear direction are laid on a bed 11. Both guide rails 2 are parallel to each other, and the longitudinal direction of the guide rails 2 is the Y-axis direction of the two-dimensional measuring apparatus 1. A ball screw 21 that is a feed screw is disposed between the guide rails 2 in parallel with the guide rail 2. A movable element 3 is engaged with each of the guide rails 2 so as to reciprocate in the Y-axis direction along the guide rails 2. Both movable elements 3 are provided with a portal frame 4. The portal frame 4 is composed of a horizontal table T made of a glass plate and a pair of side sides 43 that connect the upper side 41 and the lower side 42 to each other on the left and right sides. . For example, as shown in Japanese Patent Application No. 11-41777, the table T is fixed to the bed 11 via components not shown. The upper side 41 is formed to be long in the X-axis direction, which is a direction perpendicular to the Y-axis direction, and holds the movable element 5 to which the CCD camera 51 is attached so as to be reciprocable in the X-axis direction. . A nut holder 44 is attached to a substantially central portion of the lower side 42 in the left-right direction and is screwed into the ball screw 21. Therefore, when the ball screw 21 is rotated by a servo motor (not shown), the portal frame 4 moves along the guide rail 2 in the Y-axis direction. By the way, in this invention, the support plate 6 which is a support member was constructed by the needle | mover 3 by which the portal frame 4 was constructed so that it might not contact the portal frame 4. A linear scale 7 that is long in the Y-axis direction is disposed between the guide rails 2, and a head amplifier 71 that reads the scale of the linear scale 7 is attached to the lower surface of the support plate 6. Accordingly, as described above, when the portal frame 4 moves in the Y-axis direction, the head amplifier 71 also moves in the Y-axis direction, and the Y coordinate of the CCD camera 51 is detected by reading the scale of the linear scale 7 at the point of movement. can do.
[0009]
In the above two-dimensional measuring apparatus 1, it is necessary to increase the rigidity of the portal frame 4 so that the CCD camera 51 does not vibrate, and the portal frame 4 is formed thick. Therefore, the mass of the portal frame 4 is increased, and a large driving force is required to drive the portal frame 4 in the Y-axis direction. The large driving force acts on the substantially central portion of the lower side 42 via the nut holder 44. Then, although slightly, the lower side 42 is elastically deformed in the direction in which the driving force is applied. Even if the portal frame 4 is stopped, the elastic deformation of the lower side 42 is not completely recovered due to friction or the like. Therefore, the relative position between the nut holder 44 and the CCD camera 51 differs depending on the moving direction of the portal frame 4. However, even if the central portion of the lower side 42 is elastically deformed, both end portions of the lower side 42, that is, the portion that is in contact with the movable element 3 is not elastically deformed, so that the relative position between the CCD camera 51 and the movable element 3 is the portal frame. There is no difference depending on the moving direction of 4. Accordingly, the relative position between the support plate 6 installed on the movable element 3 and the CCD camera 51 does not change without coming into contact with the portal frame 4, and the support plate 6 is not deformed because an external force does not act on the support plate 6. Similarly, the relative position between the head amplifier 71 attached to 6 and the CCD camera 51 does not change.
[0010]
Although not shown, a guide rail for moving the CCD camera 51 back and forth in the X-axis direction, a ball screw, and a linear scale for detecting the X coordinate are arranged on the upper side 41 of the portal frame 4. The present invention also relates to a three-dimensional measuring apparatus that holds the CCD camera 51 so that the imaging direction of the CCD camera 51 is horizontal and can reciprocate in the Z-axis direction that is the vertical direction. Can be applied.
[0011]
【The invention's effect】
As is clear from the above description, the present invention provides a head amplifier that is constructed even when the gate-shaped frame is elastically deformed because the support member that does not contact the portal frame is installed on the movable element and the head amplifier is attached to the support member. The relative position between the camera and the camera does not change, and no measurement error occurs.
[Brief description of the drawings]
FIG. 1 is a diagram showing the configuration of an embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 Main part of two-dimensional measuring apparatus 2 Guide rail 3 Movable element 4 Portal frame 6 Support plate 7 Linear scale 51 CCD camera 71 Head amplifier

Claims (1)

It has a flat table on which the object to be measured is placed, and is located above the table and holds the camera that images the object to be measured, and a horizontal upper side that is located below the table and parallel to the upper side And a pair of vertical sides connecting the both ends of the upper side and the lower side, and a pair of guide rails arranged parallel to each other below the table. The mover holds both ends of the lower side, and a nut that drives the gate-shaped frame along the guide rail by screwing it into a feed screw arranged in parallel with the guide rail is attached to the substantially central portion of the lower side. In a measuring device that detects the scale of the linear scale arranged in parallel with the head amplifier moving with the portal frame and obtains the coordinates of the camera, a support portion is provided so that the two movable elements do not contact the portal frame. The bridged, characterized in that the mounting head amplifier to the support member measuring device.

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