JPH0522814Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention measures the dimensions of an object to be measured by placing it on an X-Y table, and uses a calibration plate to correct the measured values. Concerning a measuring device.

PRIOR TECHNOLOGY There are various types of devices for measuring dimensions, and while some are very common and familiar, there are also complex devices that use laser beams, and they vary depending on the purpose of use and measurement accuracy. It is used for different purposes. One of these devices for measuring dimensions is an X-
There is a dimension measuring device that includes a Y table, a linear scale that measures the amount of movement in each direction, a sighting device that performs positioning, and the like. This device is
Place the object to be measured on the Y table and move the X-Y table to align the point to be measured with the cursor of the aiming device. The dimensions of the object to be measured are measured by measuring the amount of movement of the X-Y table in both the X and Y directions at that time. Therefore, measurements are performed on the assumption that when moving in the X direction, the amount of movement in the Y direction is 0, and when moving in the Y direction, the amount of movement in the X direction is 0.

Problems that the invention aims to solve However, in reality, errors occur in the measured values due to deviations such as the guide rails in each direction being slightly bent or not completely orthogonal. Measurement accuracy was limited depending on the degree of deviation. However, the repeat accuracy is higher than the measurement accuracy, and the way errors occur is almost constant each time.

The present invention was devised with attention paid to the above-mentioned properties, and an object of the present invention is to provide a dimension measuring device capable of performing highly accurate measurements based on the repeatability of an X-Y table.

Means for Solving the Problems The dimension measuring device of the present invention uses a calibration plate, which is a plate material used to calibrate the device, and has a plurality of two-dimensionally arranged markers formed on its surface. As in the case of measuring the dimensions of the object to be measured, on the premise that the calibration plate is placed at a predetermined position on the X-Y table and the X-axis and Y-axis coordinate values B of multiple markers are obtained, the coordinate values are Based on the X-axis and Y-axis coordinate values A of the measurement point
and a calculation unit that corrects the・A storage unit that records the Y-axis coordinate value C for each marker, and the X-axis and Y-axis coordinate value A of the measurement point
By comparing the X-axis and Y-axis coordinate values B of multiple markers, the markers M surrounding the measurement point are identified, and the X-axis and Y-axis coordinate values of the marker M are compared.
B _M , means for reading out the accurate X-axis and Y-axis coordinate values C _M of the marker M from the recording section, and means for reading out the accurate X-axis and Y-axis coordinate values C _M of the marker M and the accurate X-axis and means for determining the error from the Y-axis coordinate value C _M ;
It is characterized by comprising means for correcting the X-axis and Y-axis coordinate values A of the measurement point based on the error data.

Function Similar to when measuring the dimensions of the object to be measured, place the calibration plate on the X-Y table and adjust the X of multiple markers.
Axis/Y-axis coordinate values B are determined and recorded in advance (assuming that the X-axis/Y-axis coordinate values of marker M are expressed as B _M ). On the other hand, prepare and record accurate X-axis and Y-axis coordinate values C of multiple markers in advance (marker M
Let the exact X-axis and Y-axis coordinate values of CM be expressed as C _M ).

The object to be measured is placed on an X-Y table, and the X-axis and Y-axis coordinate values A of the measurement point are determined. The X-axis and Y-axis coordinate values A of the measurement point are corrected by the following processing.

First, by comparing the X-axis and Y-axis coordinate values A of the measurement point with the X-axis and Y-axis coordinate values B of multiple markers, the markers M surrounding the measurement point are identified, and the X-axis and Read out the Y-axis coordinate value B _M and the accurate X-axis and Y-axis coordinate values C _M of the marker M.

Then, the error between the X-axis/Y-axis coordinate value BM of the marker _M and the accurate X-axis/Y-axis coordinate value CM of the marker _M is determined. Based on this error data,
Correct the axis/Y-axis coordinate value A.

Embodiment FIG. 1 is a perspective view schematically showing an embodiment of the present invention. In the figure, the X-Y table 11 is composed of an X-axis table 26 and a Y-axis table 23 that move in directions perpendicular to each other.
is guided by two parallel Y-axis rails 22 fixed on the board 21, and the X-axis table 26 is guided by two parallel X-axis rails 25 provided on the Y-axis table 23. do. The Y-axis linear scale 13 is fixedly attached to a substrate 21, and the X-axis linear scale 12 is fixedly attached to a Y-axis table 23, and converts the amount of movement of each table 23, 26 into an electric signal. This electrical signal is sent to the arithmetic unit 15 via an interface 53, such as a linear scale counter.
be taken in. As the arithmetic unit 15, a small computer having a keyboard 51, CRT 52, etc. is employed.

An object to be measured 32 is placed on the X-axis table 26,
For example, when a PC board etc. is placed on the
When moving the Y table 11 to bring the measurement point of the object 32 to a predetermined position, an optical microscope or the like is used as an aiming device 41 (not shown), which provides aiming to accurately achieve this. It is fixed in the space above the XY table 11 by a support section. A backing plate 31 is placed on the X-axis table 26 so that the object to be measured 32 can always be placed at a fixed position on the X-axis table 26.
is installed.

FIG. 2 is a partial view showing one embodiment of the calibration plate of the present invention.

The calibration plate 17 has markers formed on the surface of the calibration plate body, but since the calibration plate 17 requires accuracy, the calibration plate body is made of a material that is difficult to deform, such as Alcoa Plus Plate. The aluminum plate sold under the same name is used.

In addition, the marker is composed of holes 1 of minute radius formed at each intersection of the squares, and each hole 1 is
When the calibration plate 17 is placed on the X-axis table 26,
Accurate values indicating the positional relationship with the reference position are measured in advance in each of the X and Y directions using an extremely precise measuring instrument, with the corner touching the patch plate 31 as the reference position. The list of measured values is prepared in advance as a list paired with the calibration plate 17.

Now, with reference to FIG. 3, a method for correcting errors will be explained. The four points 1a ₁ to 1a ₄ are the calibration plate 1
7 shows the center position of hole 1a.

This calibration plate 17 is placed on the X-Y table 11 so that the corner serving as the reference position is in contact with the backing plate 31, and the measurement is performed, and the resulting values (X-axis linear scale 12 and Y-axis The values given by the linear scale 13) are set as (x ₁ , y ₁ ) to (x ₄ , y ₄ ) for the four points 1a ₁ to 1a ₄ , and the exact value of each hole 1a ₁ to 1a ₄ is determined. Let the position values be (X ₁ , Y ₁ ) to (X ₄ , Y ₄ ). Each measurement value (x ₁ ,
There is an error between y ₁ ) and (x ₄ , y ₄ ), and the error value representing that error is expressed as (Δx ₁ , Δy ₁ ) to (Δx ₄ ,
Δy ₄ ).

Δx ₁ =x ₁ −X ₁ Δy ₁ =y ₁ −Y ₁ .

The following values up to Δx ₄ and Δy ₄ are obtained in the same manner.

Therefore, when the measured value at that time is (x, y) for the point 201 whose measured value is in the area 301 surrounded by the four points 1a ₁ to 1a ₄ , correction is performed by first-order approximation. And, the corrected measurement value (X, Y) which is a more accurate value at point 201 is A=Δx ₁ (x ₂ −x)+Δx ₂ (x−x ₁ )/x ₂ −x ₁ B=Δx ₃ ( x ₄ −x) + Δx ₄ (x−x ₃ )/x ₄ −x ₃ C=Δy ₁ (y _{1 −} y)+Δy ₃ (y−y ₃ )/y ₃ −y ₁ D=Δy ₂ (y− y ₄ )+Δy ₄ (y ₂ −y)/y ₂ −y ₄ , X=A×(y−y ₃ )+B×(y ₄ −y)/y ₁ −y ₃ Y=C×(x−x ₁ )+D×(x ₂ −x)/x ₂ −x ₁ .

Next, the operation will be explained with reference to FIGS. 1 and 2. First, before measuring the PC board 32, the calibration plate 17 is placed on the X-Y table 11, and the position of each hole 1 is measured and read into the arithmetic unit 15 ( ), and in parallel with that operation, each hole 1 of the calibration plate 17 is read from the keyboard 51.
The error value is calculated by inputting and storing an accurate value indicating the positional relationship with the reference position. Next, the PC board 32 is placed and measurements are taken. Based on the measurement values obtained at that time, if the positions of the measurement points on the PC board 32 are within the square area 301 separated by the four holes 1a on the calibration plate 17, the arithmetic unit 15 A corrected measurement value is calculated based on the corresponding error value, and the calculation result is output. Further, if the position of the measurement point is within the area 303, similar calculations are performed based on each value of point 1b.

In addition to the above calculations, it is also possible to perform an approximation calculation using a curve of higher order than second order in order to further improve the accuracy of measurement, but in this embodiment, the distance between the holes 1 is shortened. is adopted. Furthermore, the accuracy of measurement using this correction method can be increased to approximately the same accuracy as the repeatability of the X-Y table 11.

The position of the holes in the calibration plate 17 is not limited to the square shape,
It is possible to randomly arrange the holes, select four holes near the measurement point, and perform correction calculations based on the error values corresponding to these holes, and the marker is the calibration plate 17. It is not limited to a hole made in the calibration plate 17, but other shapes such as a cross line drawn on the surface of the calibration plate 17 can be used.

Furthermore, the present invention can be applied to an X-ray non-destructive inspection device, etc. that positions an X-Y table based on an X-ray transmitted image of the object to be measured and measures its dimensions. An X-ray television camera or the like is used as an aiming device.

Effects of the Invention The dimension measuring device of the present invention obtains an error value indicating the error of the X-Y table by using a calibration plate whose accurate value indicating the position of the marker is known, and also obtains an error value indicating the error of the X-Y table. Since the measurement value is corrected based on
Since the accuracy is comparable to the repeatability of the Y table, it is possible to perform highly accurate measurements.

[Brief explanation of drawings]

Fig. 1 is a perspective view schematically showing an embodiment of the present invention, Fig. 2 is a partial view showing an embodiment of the calibration plate of the present invention, and Fig. 3 explains a correction method using the calibration plate. This is a diagram for 12... X-axis linear scale, 13... Y-axis linear scale, 15... Arithmetic device, 17... Calibration plate, 41... Aiming device.

Claims (1)

[Scope of claim for utility model registration] Equipped with an X-Y table and an aiming device,
- When the Y table is operated, the position of the object to be measured placed at a predetermined position on the table changes relative to the aiming device, while the X and Y axes of the measurement point are In a dimension measuring device that determines the coordinate value A and determines the dimensions of the object to be measured based on the coordinate value, a plurality of two-dimensionally arranged markers are placed on the surface of a plate used to calibrate the device. The calibration plate formed on the X-
On the premise that the calibration plate is placed at a predetermined position on the Y table to obtain the X-axis and Y-axis coordinate values B of multiple markers, the X-axis and Y-axis coordinate values A of the measurement point are corrected based on the coordinate values. The calculation device is equipped with a means for recording the X-axis and Y-axis coordinate values B of the plurality of markers for each marker, and a means for recording the accurate X-axis and Y-axis coordinate values B of the plurality of markers prepared in advance. By comparing the X-axis/Y-axis coordinate values A of the measurement point with the X-axis/Y-axis coordinate values B of multiple markers with the storage unit that records the axis coordinate value C for each marker, the measurement point can be determined. In addition to specifying the marker M surrounding the marker M, the X-axis and Y-axis coordinate values of the marker M
B _M , means for reading out the accurate X-axis and Y-axis coordinate values C _M of the marker M from the recording section, and means for reading out the accurate X-axis and Y-axis coordinate values C _M of the marker M and the accurate X-axis and means for determining the error from the Y-axis coordinate value C _M ;
A dimension measuring device comprising means for correcting the X-axis and Y-axis coordinate values A of the measurement point based on the error data.