JPH0729016A - Size measurement instrument - Google Patents

Abstract

PURPOSE:To measure the size of a work arranged on a table in a real plane by inclining it by a micro angle. CONSTITUTION:CPU fetches a picture in a view including the semiconductor package 12 of the table arranged in the real plane by controlling a CCD camera as real picture data being data for respective pixels in a logical plane and stores it into RAM. A displacement angle theta between first parallel segment groups c1 and c2 constituting the contour of the semiconductor package 12 and the X-axis of the logical plane or between a second parallel segment group d1 and a Y-axis is obtained. When the displacement angle theta is less than the previously decides micro angle thetaa, the Y-coordinate value Y1 of a first specified segment c1 or the X-coordinate value x2 of a second specified segment d1 on the logical plane is obtained. The y-coordinate value (a) of the first specified segment c1 on the coordinate plane of the semiconductor package 12 is obtained by correcting it by a correction value (X1Xtheta), and the x-coordinate value (b) of the second specified segment on the coordinate plane of the semiconductor package 12 is obtained by correcting the X-coordinate value X2 by a correction value (Y2Xtheta).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dimension measuring device, and more particularly, it is arranged on a table arranged in a real plane, and the contours thereof are parallel to each other and have a small angle with respect to the X axis of the real plane. A work coordinate plane (having the same coordinate origin as the coordinate origin of the real plane, of the workpiece constituted by the displacing first parallel line segment group and the second parallel line segment group orthogonal to the first parallel line segment group, y-coordinate value a of the first parallel line group in the xy orthogonal coordinate system plane in which the x-axis is parallel to the first parallel line group.
Alternatively, the present invention relates to a dimension measuring device that measures the x coordinate value b of the second parallel line segment group.

[0002]

2. Description of the Related Art Conventionally, for example, a work arranged on a table arranged in a real plane which is an X-Y orthogonal coordinate system plane (particularly a first parallel line segment group and a first parallel line segment whose contours are parallel to each other). It is composed of a second group of parallel line segments orthogonal to the group of parallel line segments. As an example, to measure the dimensions of the outer leads and the package of the semiconductor package), a dimension measuring device that employs a computer image processing technology is used. Has been. The dimension measuring apparatus uses an image in a field of view on a table on which a semiconductor package is arranged, digital data for each pixel in a logical plane which is an XY orthogonal coordinate system plane having the same coordinate origin as the real plane. It is composed of a CCD camera for taking in as real image data, a RAM for storing the real image data, and a CPU. With this configuration, the CPU controls the CCD camera to create actual image data and stores the actual image data in the RAM. Next, the semiconductor package arranged on the table is usually slightly tilted with respect to the coordinates of the real plane (the first parallel line segment group and the X axis of the logical plane, or the second parallel line segment group and the logical plane of the logical plane). The angle θ (radian) is displaced from the Y axis)
Therefore, the CPU uses the actual image data stored in the RAM to determine the first parallel line group of the semiconductor package and the X of the logical plane.
The displacement angle θ between the axis or the second parallel line group and the Y axis of the logical plane is obtained. Subsequently, the CPU performs angle correction by rotational movement for the displacement angle θ with respect to the coordinate values of the first parallel line segment group and the second parallel line segment group obtained from the actual image data in the RAM, and the semiconductor package Find the dimensions of.

[0003]

However, in the above-described dimension measuring apparatus, the CPU corrects the angle of the coordinate of the line segment forming the contour of the work obtained on the logical plane in the RAM by the rotational movement. Therefore, there is a problem that it takes time to measure the dimensions. Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide a dimension measuring device capable of measuring the dimension of a work arranged at a minute angle on a table in a real plane in a short time. It is in.

[0004]

The present invention has the following constitution in order to achieve the above object. That is, a first group of parallel line segments which are arranged on a table arranged in a real plane which is a plane of an XY orthogonal coordinate system and whose contours are parallel to each other and are displaced by a slight angle with respect to the X axis. And a workpiece having a second parallel line segment group orthogonal to the first parallel line segment group, having the same coordinate origin as the coordinate origin of the real plane,
The y-coordinate value a of the first parallel line segment group or the x-coordinate value of the second parallel line segment group on the work coordinate plane in which the x-axis is the xy orthogonal coordinate system plane parallel to the first parallel line segment group. In a dimension measuring device for measuring b, an image in a visual field including the work in the real plane is a logical plane that is the same XY orthogonal coordinate system plane having the same coordinate origin as the coordinate origin of the real plane. Based on the actual image data, an input unit for capturing as actual image data that is data for each pixel in the inside, a storage unit for storing the actual image data,
Angle detection means for detecting a displacement angle θ (radian) between the first parallel line segment group and the X axis of the logical plane, or between the second parallel line segment group and the Y axis of the logical plane, and the actual image data. On the basis of the specific X coordinate value X1 and the Y coordinate value Y1 of the first specific line segment included in the first parallel line segment group in the logical plane, or Coordinate detection means for obtaining the specific Y coordinate value Y2 and the X coordinate value X2 of the two specific line segments, and the input means to control the image in the field of view including the work in the real plane to be captured as real image data, When the displacement angle θ is equal to or smaller than the predetermined minute angle, the Y coordinate is controlled by controlling the coordinate detecting unit. Calculate the value Y1 or the X coordinate value X2 The y coordinate value a of the first specific line segment on the work coordinate plane is obtained by correcting the Y coordinate value Y1 by a correction value (X1 × θ), and the second specific line segment work coordinate plane is obtained. The x-coordinate value b in 1. is provided with a control means for correcting the X-coordinate value X2 with a correction value (Y2 × θ).

[0005]

By controlling the input means, the image in the field of view including the work in the real plane is fetched as the real image data which is the data for each pixel in the logical plane and stored in the storage means. By controlling the angle detecting means, a displacement angle θ between the first parallel line segment group forming the contour of the work and the X axis of the logical plane, or the second parallel line segment group and the Y axis is obtained. When the displacement angle θ is less than or equal to a predetermined minute angle, the coordinate detecting means is controlled to obtain the Y coordinate value Y1 or the X coordinate value X2 of the second specific line segment on the logical plane. Then, the y coordinate value a on the work coordinate plane of the first specific line segment is obtained by correcting the Y coordinate value Y1 with the correction value (X1 × θ), and on the work coordinate plane of the second specific line segment. The x-coordinate value b can be obtained by correcting the X-coordinate value X2 with the correction value (Y2 × θ).

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a flow chart for explaining the operation of the dimension measuring apparatus according to the present invention. Figure 2
FIG. 4 is an explanatory diagram for obtaining a correction value for correcting the coordinate value on the logical plane to the coordinate value on the work coordinate plane, and a correction calculation formula. FIG. 3 is a block diagram showing the configuration of the dimension measuring apparatus of FIG.

First, the configuration of the apparatus of this embodiment will be described with reference to FIGS. 2 and 3. The dimension measuring apparatus according to the present embodiment is an apparatus for measuring the dimension of a semiconductor package which is an example of an object to be measured (workpiece). Reference numeral 10 is a table arranged in a real plane which is a plane of an XY orthogonal coordinate system.
The table 10 is movable in the X-axis and Y-axis directions of the real plane in response to a drive signal from a CPU described later. 12
Is a semiconductor package arranged on the table 10. The semiconductor package 12 has a first parallel line segment group whose contours are parallel to each other and displaced by a small angle θ (radian) of less than 1 radian with respect to the X-axis, and a second parallel line segment orthogonal to the first parallel line segment group. It is composed of line segments. For example, the outer lead 14 of the semiconductor package 12 shown in FIG.
In, the first parallel line segment group is c1 and c2, and the second parallel line segment group is d1. Reference numeral 16 is a CCD camera as an input means, which is a semiconductor package 12 in a real plane.
Has a function of taking in an image in the field of view including the image data as real image data which is data for each pixel in a logical plane which is the same XY orthogonal coordinate system plane having the same coordinate origin as the coordinate origin O of the real plane. .

Reference numeral 18 denotes a CPU which, based on the actual image data, has a displacement angle θ (radian) between the first group of parallel line segments and the X axis of the logical plane or between the second group of parallel line segments and the Y axis of the logical plane. It has a function as an angle detecting means for detecting. Further, the CPU 18 uses the actual image data stored in the RAM serving as a storage unit described later, based on the specific X coordinate value X of the first specific line segment included in the first parallel line segment group on the logical plane.
It has a function as coordinate detecting means for obtaining the Y coordinate value Y1 at 1 or the X coordinate value X2 at the specific Y coordinate value Y2 of the second specific line segment included in the second parallel line segment group. Further, the CPU 18 controls the CCD camera 16 to capture an image in the field of view including the semiconductor package 12 in the real plane as real image data and stores it in RAM described later, and the displacement angle θ is a predetermined minute angle θa ( For example, θa << 1
Radian) In the following cases, the function as the coordinate detecting means is operated to obtain the Y coordinate value Y1 or the X coordinate value X2, and the first coordinate
Of the specific line segment of the work coordinate plane (which has the same coordinate origin as the coordinate origin of the real plane, and the x axis is parallel to the first parallel line group).
-Y at a specific x-coordinate value X1 in the (y-orthogonal coordinate system plane)
The coordinate value a is obtained by correcting the Y coordinate value Y1 with the correction value (X1 × θ), and the x coordinate value b at the specific y coordinate value Y2 on the work coordinate plane of the second specific line segment is the X coordinate value X2. It has a function as a control unit that corrects and obtains the correction value (Y2 × θ).

Specifically, referring to FIG. 2, the above-mentioned correction value,
A calculation method for obtaining the y-coordinate value a and the x-coordinate value b using the correction values will be described. The contour of the outer lead 14 is
As described above, it is configured by the first parallel line segment groups c1 and c2 and the second parallel line segment group d1, and the first parallel line segment groups c1 and c2 are with respect to the X axis of the XY orthogonal coordinate of the real plane. It is displaced by an angle θ (note that the angle θ is θ ≦ θa). Further, it is assumed that the X coordinate value X1 is X1 ≧ 0 and the Y coordinate value Y2 is Y2 ≧ 0. First, as an example, using c1 of the first parallel line segment groups c1 and c2 as the first specific line segment, the y coordinate value a at the specific x coordinate value X1 on the work coordinate plane (xy coordinate) of the line segment c1. On the logical plane (X-Y
Specific X coordinate value X1 in (coordinates), Y coordinate value Y1 of line segment c1 at the X coordinate value X1, and angle θ. It should be noted that the intersection point between the X axis and the straight line parallel to the Y axis including the point P (X1, Y1) of the line segment c1 is the point Q, and the intersection point with the x axis is the point R.
And Also, it is a point on the x-axis, and the origin of the xy coordinates is O.
A point whose distance from X is X1 is a point S, and an intersection of a straight line including the point S and parallel to the Y axis and a line segment c1 is a point T. In FIG. 2, L1 (distance between points Q and R) is represented by the following formula. L1 = X1 × tan θ Therefore, L2 (distance between point R and point P) is given by the following equation: L2 = Y1-L1 = Y1- (X1 × tan θ) L2 = L3 (between point S and point T) Therefore, the y-coordinate value a at the specific x-coordinate value X1 on the work coordinate plane (xy coordinates) of the line segment c1 to be obtained is a = L3 × cos θ = (Y1- (X1 × tan θ)) × cos θ = Y1 × cos θ-X1 × sin θ. When the angle θ satisfies | θ | << 1 radian, the following approximate expression holds and sin θ = θ, cos θ = 1 The calculation formula (1) for obtaining the y coordinate value a is a = Y1− X1 × θ. The correction value is (X1 × θ).

Further, the x coordinate value b of the line segment d1 as the second specific line segment included in the second parallel line segment group at the specific y coordinate value Y2 on the work coordinate plane is the same as the y coordinate value a. It is calculated by the following calculation formula (2). b = X2 + Y2 × θ The correction value is (Y2 × θ). Further, the calculation formula (1) is obtained when the X coordinate value X1 is X1 ≧ 0, and the calculation formula (2) is obtained when the Y coordinate value Y2 is Y2 ≧ 0. The calculation formula (1) is satisfied even when X1 is X1 <0, and the calculation formula (2) is also satisfied when the Y coordinate value Y2 is Y2 <0.

Reference numeral 20 is a RAM forming a part of the storage means. The RAM 20 has a first area, a second area, and a third area.
Area and a fourth area. The actual image data is stored in the first area, and the specific image data is stored in the second area.
Y coordinate value Y1 at coordinate value X1 and specific Y coordinate value Y2
The X coordinate value X2 at is stored. Further, the obtained y coordinate value a and x coordinate value b are stored in the third area, and the obtained displacement angle θ is stored in the fourth area. 22
Is a ROM that constitutes a part of the storage means. ROM22
The inside is divided into a fifth area, a sixth area, a seventh area, an eighth area, and a ninth area. The minute angle θa is in the fifth area, and the specific X coordinate value X1 and the specific Y coordinate value Y2 as the measurement point data are in the sixth area.
The area 8 indicates the measurement program that defines the operation of the CPU 18, the eighth area indicates the data for determining the field of view of the CCD camera 16, and the ninth area indicates the calculation program (correction) for the above correction. The value and the calculation formula for the correction) are respectively set in advance in the monitor 24 and the keyboard 2.
6 is stored via the CPU 18. Also,
Distance correction data on the real plane per unit pixel on the logical plane is also stored in the eighth region.

Next, the operation of the dimension measuring device will be described with reference to FIGS. As an example, a procedure for obtaining the y coordinate value a of the line segment c1 of the first parallel line segment group will be described. First, when the power is turned on, the CPU 18 follows the RAM 20 according to the measurement program stored in the seventh area.
The area is cleared and the field size of the CCD camera 16 is determined (step 100). The CPU 18 sends a control signal to the table 10, and moves the table 10 in the X-axis or Y-axis direction in a real plane so that, for example, a mark (not shown) previously arranged on the table 10 falls within the field of view of the CCD camera 16. The coordinate origin of the real plane coordinates (that is, the coordinate origin of the logical plane) and the coordinate origin of the work coordinate plane are made to coincide with each other. In addition, the displacement angle θ with respect to the X-axis of one line segment of the first parallel line segment group forming the contour of, for example, the outer lead 14 of the semiconductor package 12 is also obtained and stored in the fourth region. Since the first group of parallel line segments is parallel to the x-axis of the work coordinate plane, the displacement angle θ is the displacement angle between the XY coordinates of the logical plane and the xy coordinates of the work coordinate plane (step 102). ). In addition, CCD
The real image data in the field of view captured by the camera 16 is stored in the first area each time.

Next, the CPU 18 reads the minute angle θa from the fifth area and compares it with the obtained displacement angle θ (step 104). As a result of the comparison, when θ> θa, the error in the above-mentioned approximate expression becomes large, and therefore an error message is output to the monitor 24 (step 106) and the operation is stopped. When θ ≦ θa, the CPU 18 determines the remaining number of the specific X coordinate value X1 or the specific Y coordinate value Y2 as the measurement point data stored in the sixth area (step 108), and the data If so, the data is read (step 110) and a control signal is sent to the table 10 so that the point Q in FIG. 2 can be captured in the field of view of the CCD camera 16.
Is moved to store the actual image data in the first area (step 112). If there is no read data, the process proceeds to step 118 described later. If the CCD camera 16 is movable, the CCD camera 16 may be moved.

The CPU 18 obtains the coordinates of the point P shown in FIG. 2, that is, the Y coordinate value Y1 of the specific X coordinate value X1 of the line segment c1 and stores it in the second area (step 114). At this time, in order to convert the distance (the number of pixels) on the logical plane into the distance on the real plane, the distance correction data stored in the eighth area is used. Subsequently, a calculation program for correction is read from the ninth area, and the y-coordinate value a is calculated according to this program (calculation formula for correction described above).
Is stored in the third area (step 116). By repeating the above steps 108 to 116, 1 included in the first parallel line segment group and the second parallel line segment group
Alternatively, it is possible to obtain the y coordinate value and the x coordinate value of two or more line segments. When the specific X coordinate value X1 and the specific Y coordinate value Y2 stored in the seventh area are finished, the CPU 18 stores the y coordinate value a and the x coordinate value b stored in the third area.
Is output to an external output device such as the monitor 24 or a printer (step 118), and the dimension measurement operation is completed.

Although various preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and many modifications can be made without departing from the spirit of the invention. Of course.

[0016]

When the dimension measuring device according to the present invention is used,
Once the displacement angle θ between the real plane which is the plane of the XY coordinate system and the work coordinate plane which is the plane of the xy coordinate system is obtained, the actual image data captured by the input means as in the conventional case is obtained. Therefore, it is not necessary to process a huge amount of pixel data for performing angle correction by rotational movement for each pixel, so that the measurement time can be significantly shortened and high-speed measurement can be achieved.

[Brief description of drawings]

FIG. 1 is a flow chart for explaining the operation of a dimension measuring apparatus according to the present invention.

FIG. 2 is an explanatory diagram for obtaining a correction value for correcting a coordinate value on a logical plane to a coordinate value on a work coordinate plane, and a correction calculation formula.

FIG. 3 is a block diagram showing a configuration of a dimension measuring device according to an embodiment.

[Explanation of symbols]

 10 table 12 semiconductor package 16 CCD camera 18 CPU 20 RAM 22 ROM

Claims (1)

[Claims] 1. A first table, which is arranged on a table arranged in a real plane which is a plane of an XY orthogonal coordinate system, and whose contours are parallel to each other and are displaced by a slight angle with respect to the X axis.
Parallel line segment group and a second orthogonal to the first parallel line segment group
Work coordinates having the same coordinate origin as that of the real plane of the work constituted by the parallel line group, and the x-axis being the xy orthogonal coordinate system plane parallel to the first parallel line group. In a dimension measuring device for measuring the y-coordinate value a of the first parallel line segment group or the x-coordinate value b of the second parallel line segment group in a plane, an image in a field of view including the work in the real plane, The same X- having the same coordinate origin as the coordinate origin of the real plane
An input unit for capturing as real image data, which is data for each pixel in a logical plane that is a Y orthogonal coordinate system plane, a storage unit for storing the real image data, based on the real image data, Angle detecting means for detecting a displacement angle θ (radian) between the first parallel line segment group and the X axis of the logical plane, or between the second parallel line segment group and the Y axis of the logical plane, and the actual image data, Based on the above, the specific X coordinate value X1 and the Y coordinate value Y1 of the first specific line segment included in the first parallel line segment group on the logical plane are obtained, or the second parallel line segment group included in the second parallel line segment group is included. Y segment specific Y coordinate value Y2
And a coordinate detecting means for obtaining an X coordinate value X2, and an image in a visual field including the work in the real plane are fetched as real image data by controlling the input means, stored in the storage means, and the angle detection means. Is calculated to obtain the displacement angle θ, and when the displacement angle θ is equal to or less than the predetermined minute angle, the coordinate detecting means is controlled to obtain the Y coordinate value Y1 or the X coordinate value X2. The y coordinate value a of the first specific line segment on the work coordinate plane is obtained by correcting the Y coordinate value Y1 by a correction value (X1 × θ), and the second specific line segment work coordinate plane is obtained. The x-coordinate value b in 1. is obtained by correcting the X-coordinate value X2 with a correction value (Y2 × θ).