JPH06331653A - Measuring method for probe-to-probe error in x-y circuit substrate inspection device - Google Patents

Abstract

PURPOSE:To measure probe-to-probe errors in a short time and with accuracy. CONSTITUTION:A gouge is formed on a gouge sheet 12 by movement of a probe P according to data about reference coordinates that correspond to a particular point serving as a reference for error measurment on the gouge sheet 12 provided on an especial board 10, and then a camera 20 is moved onto the particular point to photograph the gouge, and data about the coordinates of the center of gravity of the gouge are calculated using an image processing means 30, and the data about the coordinates of the center of gravity and the data about the reference cooridnates are compared with each other to meausre probe-to-probe errors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring an error between probes in an XY circuit board inspecting apparatus, and more specifically, an error between probes for accurately measuring an error between probes by image processing. It relates to a measuring method.

[0002]

2. Description of the Related Art An XY circuit board inspection device uses an X
Since it is designed to move the board in the Y direction to inspect the board under test, it is not necessary to prepare a dedicated pin board for the board under test, especially for inspecting a large number of small quantities of board under test. It is said to be suitable.

In a normal board inspection, three moving arms L, R and M are used, and a probe is attached to each of them. For example, an error between the probes may be caused by handling during attachment or replacement. Since it easily occurs, it is necessary to measure the error in advance and absorb (adjust) it.

Therefore, first, the error between the probes is shown in FIG.
It will be described based on. The coordinates you want to touch are (x, y)
If the coordinates of the point actually touched by moving the arm based on the coordinate data are (xL, yL), | x-xL |, | y-yL | It is an error.

The causes of this error include the assembling accuracy, the reproducibility of the screw-in angle at the time of exchanging the probe, the individual difference of the probe itself, and the value thereof is about 1 mm at the maximum.

In order to measure this error, the board 1 for measurement shown in FIG. 4 is conventionally used. On the measurement-dedicated board 1, a measurement pattern 2 is formed by orthogonally crossing a plurality of lateral patterns 3 having a predetermined width and extending in the X-axis direction and a plurality of vertical patterns 4 also having a predetermined width and extending in the Y-axis direction. Are formed.

At the time of measurement, this measurement-dedicated board 1 is fixed to a fixture of a circuit board inspection device, and L, R,
It is assumed that the three moving arms of M are in contact with specific coordinates on the measurement pattern 2. At that time, the coordinates of the probe that is going to measure the error from now on are (x, y)
(See FIG. 5).

The remaining two probes are kept in contact with the measurement pattern 2 and the probe to be measured is moved in a direction away from the pattern at a fixed pitch. Check continuity with the probe.

When measuring the error in the X-axis direction, the vertical pattern 4 is used, and the probe to be measured is moved in the X-axis direction orthogonal to it. In addition, when measuring the error in the Y-axis direction, the horizontal pattern 3 is used,
The probe to be measured is moved in the Y-axis direction orthogonal to it.

In the continuity confirmation, if the probe originally comes off from the pattern by N movements from the coordinates (x, y) and becomes non-conduction, it takes N + 2 times.
The error at that time is represented as | {N− (N + 2)} × moving fixed pitch |.

This is performed in the X and Y directions of each probe to obtain error data thereof, and this error amount is added to the movement data of the probe in advance so that the probe can be brought into accurate contact with the measured point. .

[0012]

However, according to this conventional example, if the measurement pattern is fatigued due to contact, an error easily occurs. Further, if there is an error between the outer shape of the measurement-dedicated board 1 and the measurement pattern 2, that error is also included in the inter-probe error. Further, there is a problem that it cannot be applied when the probe has a special shape.

[0013]

The present invention has been made in view of the above-mentioned conventional circumstances, and the structural features thereof are X
An X-axis having at least two arms that can move in the Y-axis direction, each of which is provided with a probe, and the probe is moved up and down in the Z-axis direction at a predetermined measurement point to measure the circuit board to be inspected. In the Y circuit board inspection device, a dedicated board for measuring the error between the probes, which has a dent sheet and is fixed at a predetermined position of the circuit board inspection device, an imaging means capable of moving on the dedicated board, and an imaging device for the same. Image processing means for measuring the center of gravity of the figure imaged by the means by arithmetic processing, and moving the probe based on reference coordinate data corresponding to a specific point serving as an error measurement reference on the dent sheet. After forming a dent on the same dent sheet, the image pickup means is moved onto the specific point to image the dent, and the image processing means obtains the coordinate data of the center of gravity of the dent, and the same center of gravity is obtained. Coordinate By comparing the data and the reference coordinate data is to have so as to measure an error between each probe.

In this case, a special mark for setting the initial mounting position of the image pickup means is provided on the dedicated board,
It is preferable that the mark is picked up by the image pickup means, the center of gravity of the mark is measured by the image processing means, and the image pickup means is set at the position of the center of gravity before the error measurement.

[0015]

First, the arm is moved onto the dent sheet based on the reference coordinate data corresponding to the specific point serving as the error measurement reference, and the probe is lowered to form the dent on the sheet.

Thereafter, the image pickup means is moved to a specific point to image the dent, the barycentric coordinate data of the dent is obtained from the image processing means, and the same barycentric coordinate data is compared with the reference coordinate data. Thus, the error between the probes is measured.

[0017]

Embodiments of the present invention will be described below with reference to FIGS. In the present invention, a dedicated board 10 for error measurement, a camera 20 as an image pickup means, and an image processing means 30 capable of measuring the center of gravity of a graphic imaged by the camera 20 by arithmetic processing are used.

The dedicated board 10 has a board 11 fixed to a fixture of a circuit board inspection apparatus (not shown), and a dent sheet 12 and a camera mounting error absorbing mark 13 are provided at predetermined positions on the board 11. Has been. In this embodiment, pressure-sensitive paper is used as the dent sheet 12.

Although not shown, the camera 20 is held by an arm like the probe so that it can move freely on the dedicated board 10 in the XY directions. For example, a CCD camera is used.

The image processing means 30 has a function of obtaining the center of gravity of the closed figure having a predetermined area by calculating the arithmetic mean of the outline coordinates of the figure, which may be a known one. .

Next, the operation of the present invention will be described.
First, the mounting error of the camera 20 is measured, and the error is absorbed (adjusted). For this purpose, the camera 20 is moved onto the mark 13, the figure is imaged, and the image processing means 30 obtains the center of gravity thereof. Then, the coordinate data of the camera 20 is adjusted to match the position of the center of gravity.

Next, a command signal is output to the probe P so as to strike a specific point (x, y) on the dent sheet 12.
After that, the center of the camera 20 is moved to a specific point (x, y), and the dents made by the probe P are imaged.

As a result, the image processing means 30 obtains the center of gravity from the dent shape. In this embodiment, the coordinate data of the center of gravity is input to the CPU 40 and the specific point (x,
The difference with y) is obtained. Here, if the coordinate data of the center of gravity is (xL, yL) as shown in FIG. 2, the error is obtained as | x−xL |, | y−yL |.

The coordinates of the probe P are set in consideration of this error, and in this example, the error is displayed on the display 50. In this way, the coordinates of each probe are set by absorbing the error between the probes.

In this embodiment, the image processing means 30 and the CPU 40 are described as separate blocks for convenience of description, but the image processing means 30 may be provided with the function of the CPU 40, and on the other hand, the CPU 40 may be provided. Of course, the function of calculating the center of gravity of the image processing means 30 may be included.

[0026]

As described above, according to the present invention, the dents made by the probe are imaged by the camera, and the center of gravity thereof is obtained by the image processing means. Moreover, it is possible to measure with high accuracy.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the operation of the embodiment.

FIG. 3 is an explanatory diagram for explaining an error between probes.

FIG. 4 is a plan view showing a conventional dedicated board for error measurement.

FIG. 5 is a plan view showing a part of a measurement pattern formed on a conventional dedicated board.

[Explanation of symbols]

 10 dedicated board 11 substrate 12 dent sheet 13 camera mounting error absorption mark 20 camera 30 image processing means 40 CPU

Claims (2)

[Claims] 1. At least two movable in the X-Y axis direction.
An XY circuit board inspection device that has two arms, attaches a probe to each of them, and raises and lowers the probe in the Z-axis direction on a predetermined measured point to measure an inspected circuit board. And a dedicated board for measuring an error between probes, which is fixed at a predetermined position of the circuit board inspection device, an image pickup means movable on the dedicated board, and a center of gravity of a graphic imaged by the image pickup means. And an image processing means for measuring the dents on the dent sheet by moving the probe based on reference coordinate data corresponding to a specific point serving as an error measurement reference on the dent sheet. After that, the image pickup means is moved to the specific point to image the dent, the barycentric coordinate data of the dent is obtained by the image processing means, and the same barycentric coordinate data is compared with the reference coordinate data. You The probe-to-probe error measuring method in the XY circuit board inspection apparatus is characterized in that the probe-to-probe error is measured. 2. The special board is provided with a specific mark for setting an initial mounting position of the image pickup means, and the mark is picked up by the image pickup means prior to error measurement, and the image is also displayed. 2. The method for measuring an error between probes in an XY circuit board inspecting apparatus according to claim 1, wherein the processing means measures the center of gravity and the image pickup means is aligned with the position of the center of gravity.