JP2002221550A - Mounting position correction method of position measuring camera in double-sided board inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove an error factor of positioning control of an inspection probe in a double-sided board inspection device by grasping accurately the error of the mounting position of a position measuring camera. SOLUTION: The board 51 having a through hole 54 as a reference mark 53 is fixed, and movable bodies 14, 24 equipped with the position measuring cameras 16, 26 and movable in the longitudinal and lateral directions are disposed individually in both the upward and downward directions of the board 51. Each position measuring camera 16, 26 is moved individually to the positions of theoretical coordinates and irradiated with light, and the errors of the actually mounting positions of each camera 16, 26 relative to the reference mark 53 are measured by the relation with each photographed reflected-light image. The actually mounting positions of the pair of each position measuring camera 16, 26 are corrected by the relation with the positions of the theoretical coordinates used as references based on respective error data acquired individually.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting a mounting position of a camera for position measurement in a double-sided board inspection apparatus.

[0002]

2. Description of the Related Art In order to perform predetermined inspections individually by contacting probe pins for inspection with each surface of a double-sided printed wiring board which is a substrate to be inspected by a double-sided substrate inspection apparatus, first, the inspection is performed. It is necessary to accurately position and fix the substrate at a predetermined position in the apparatus main body.

Further, in order for the inspection probe pins to accurately contact a predetermined position of the fixed substrate to be inspected, the inspection probe pins must always be moved under the correct position coordinates.

FIG. 7 shows a position measurement in a double-sided board inspection apparatus using a special dummy board as teaching for accurately bringing the inspection probe pins into contact with predetermined positions on both sides of the board to be inspected. FIG. 4 is an explanatory diagram illustrating an example of a conventional technique for correcting a mounting position of a camera.

According to FIG. 1, a dedicated dummy substrate 1 used for obtaining information necessary for correcting the mounting positions of the position measuring cameras 6 and 8 has plating on predetermined positions of a front surface 1a and a back surface 1b. By performing the processing, the one-side reference mark 3 and the other-side reference mark 4 that are prepared as circular reflection surfaces having the same shape are formed in an arrangement relationship in which they face each other. A non-reflective surface 5 coated with a non-reflective resin is formed in each peripheral region of the exclusive dummy substrate 1 except for the one-side reference mark 3 and the other-side reference mark 4.

The upper and lower sides of the fixed dummy substrate 1 are arranged under a positional relationship such that the respective lens surfaces 7 and 9 can face the corresponding one-side reference mark 3 or the other-side reference mark 4. The position measuring cameras 6 and 8 which can be moved in a controlled manner in the vertical and horizontal directions are separately provided.

For this reason, by irradiating light from the position measuring cameras 6 and 8 in the direction of the plate surface 2 of the dedicated dummy substrate 1, the light is reflected to the reflecting surface as the one-side reference mark 3 or the other-side reference mark 4. The irradiation light reaches the lens surface 7 or the lens surface 9 as reflected light, while the one-side reference mark 3
Alternatively, the irradiation light to the surrounding non-reflective surface 5 excluding the other-side reference mark 4 is not reflected, so that the one-side reference mark 3 or the other-side reference mark 4 and its surroundings are displayed on the images captured by the position measurement cameras 6 and 8. By producing a sharp contrast with the region, the positional relationship can be accurately grasped.

Therefore, the surface 1a of the dedicated dummy substrate 1
The position of the one-side reference mark 3 corresponding to the position measuring camera 6 disposed on the side is set to the other-side reference mark corresponding to the position measuring camera 8 disposed on the back surface 1b side of the dedicated substrate 1. By teaching the positions of the marks 4 in advance, errors in the mounting positions of the position measuring cameras 6 and 8 are measured, and the measurement results are individually stored as error data. The actual mounting positions of the measuring cameras 6 and 8 can be corrected.

[0009]

By the way, each of the position measuring cameras 6 and 8 needs to accurately calculate an error between the camera and the actual mounting position so that the same position coordinates can be secured. . For that purpose, it is a precondition that the one-side reference mark 3 attached to the front surface 1a side of the dedicated dummy substrate 1 and the other-side reference mark 4 attached to the back surface 1b exactly face each other. Becomes

[0010] However, it is difficult to make the one-side reference mark 3 and the other-side reference mark 4 exactly face-to-face due to manufacturing problems, and as shown in FIG. It was in a situation where they could live. Therefore,
As a result of the positional deviation between the one-side fiducial mark 3 and the other-side fiducial mark 4 being unable to accurately grasp the mounting position error between the position measuring cameras 6 and 8, this is actually performed. There has been an inconvenience that it becomes an error factor in the positioning control of the inspection probe pins at the time of substrate inspection.

The present invention has been made in view of the above-mentioned problems encountered in the conventional method, and accurately grasps an error of a mounting position between cameras for position measurement, and controls an error in positioning control of an inspection probe when actually performing a substrate inspection. It is an object of the present invention to provide a method for correcting a position of a camera for position measurement in a double-sided board inspection apparatus capable of eliminating the factors.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and has as a reference mark a through hole provided with a reflective surface in a peripheral area on both front and back surfaces including at least an inner peripheral surface thereof. The substrate is fixed in the apparatus main body, and a position measuring camera attached with the lens surface facing the plate surface is provided, and one or more movable bodies that can be controlled in the vertical and horizontal directions are freely moved up and down the substrate. Along with being arranged separately in an arrangement relationship in which the pair is opposed to each other in both directions, one of the position measurement cameras in the paired movable bodies is moved to a position of theoretical coordinates to be a predetermined reference. Move and irradiate the light, measure the error of the actual mounting position of the camera with respect to the theoretical coordinates in relation to the reflected light image from the reference mark side taken at that time, one of the position measurement camera side of In a situation where bright light does not interfere, the other position measuring camera of the paired movable bodies is moved to a position of theoretical coordinates to be a predetermined reference and irradiated with light, and photographing is performed at that time The error of the actual mounting position of the camera with respect to the theoretical coordinates is measured in relation to the reflected light image from the reference mark side, and the pair of movable bodies is paired based on the respective error data obtained separately. There is a structural feature in that the actual mounting position of each position measurement camera is corrected in relation to the position of the theoretical coordinates to be a reference.

In this case, as the substrate, either a substrate to be inspected, which is a double-sided printed wiring board, or a dedicated dummy substrate separately prepared as a reference may be used.

[0014]

FIG. 1 is a side view showing an example of a configuration of a main part of a double-sided board inspection apparatus provided for carrying out the present invention, and FIG. 2 is a plan view of the same.

According to these figures, a substrate 51 (substrate to be inspected 52 as a double-sided printed wiring board in FIGS. 1 and 2)
After being positioned with respect to the position fixing reference point 32, it can be fixed in the apparatus main body 11 via a holding member 31 having an appropriate structure as shown in FIG. Also,
Illumination devices 18 and 28 are provided in both the upper and lower directions with respect to the plate surface 51a in the horizontal plane direction of the substrate 52 to be inspected.
27 is provided with position measuring cameras 16 and 26 mounted to face the plate surface 51a, and inspection probe pins 15 and 25 arranged to be able to move up and down so that controlled movement in the vertical and horizontal directions is free. The movable bodies 14 and 24 are separately arranged in a paired arrangement facing each other.

That is, the movable body 14 located above the substrate 52 to be inspected is driven by a transfer command from a CPU provided in the apparatus body 11, for example, as shown in FIG.
9 and the like, and is freely movable along the Y-axis arm 13. The Y-axis arm 13 is also freely movable along the X-axis arm 12. For this reason, the inspection probe pin 15 moves in the X-axis direction, the Y-axis direction, and the Z-axis direction.
The movement in the axial direction and the movement in the Y-axis direction can be freely performed, and the movable body 14 is installed on the movable body 14.

The movable body 24 located below the substrate 52 to be inspected is attached to the Y-axis arm 23 via, for example, a servomotor 29 shown in FIG. The Y-axis arm 23 is also arranged to be freely movable along the X-axis arm 22. For this reason, the inspection probe pin 25 can freely move in the X-axis direction, the Y-axis direction, and the Z-axis direction, and the position measurement camera 26 can freely move in the X-axis direction and the Y-axis direction. Thus, it is installed on the movable body 24.

With respect to the substrate 51 of the present invention, a through hole 54 provided with a reflecting surface 56 by plating a plate surface 51a located at the peripheral region of both front and back surfaces including at least the inner peripheral surface 55 with the reference mark 53 is formed. 1 and 2, a dedicated dummy substrate 61 shown in FIG. 6, for example, separately prepared as a reference may be used instead of the substrate to be inspected 52 shown in FIGS.

Next, the method of the present invention carried out by the double-sided board inspection apparatus having the above configuration will be described with reference to FIG. 3 and FIG.
2 and the device body 1 via the holder 31.
1 and the substrate set is completed.

Next, one of the position measuring cameras, for example, the upper position measuring camera 16 is moved away from the position of the reference mark 53 formed as the through hole 54 in the substrate 51, or the illuminating device 18 is moved. The light is turned off, for example, so that illumination light from above does not interfere with the other lower position measurement camera 26.

After arranging the upper position measuring camera 16 in this manner, the lower position measuring camera 26 is moved to a position of a theoretical coordinate to be a predetermined reference, and the lighting fixture 28 is moved. The light is turned on under illumination control from a CPU provided in the apparatus main body 11, and the light is irradiated to the reference mark 53 side to photograph the reflected light.

Thus, the image recognizing means measures the deviation of the reference mark 53 from the center position O ₁ by the number of pixels, accurately detects the center position O ₁ , and outputs the error measurement value via the image processing means 35. The error measurement value is converted into a distance (coordinate value as a shift amount) by a CPU provided in the apparatus main body 11.

The converted distance (coordinate value as a shift amount) is grasped as a mechanism error between the X-axis arm 22 and the Y-axis arm 23, and is stored and held in a memory provided in the apparatus main body 11.

Next, the lower position measuring camera 26
In a situation in which illumination light from below does not interfere with the upper position measurement camera 16 by moving away from the position of the reference mark 53 formed as the through hole 54 in the substrate 51 or turning off the illumination device 18. Placed in

After arranging the lower position measuring camera 26 in this way, the upper position measuring camera 16 is moved to a position of theoretical coordinates to be a predetermined reference, and the lighting device 18 is moved. The light is turned on under illumination control from a CPU provided in the apparatus main body 11, and the light is irradiated to the reference mark 53 side to photograph the reflected light.

Thus, the image recognizing means operates the reference mark 5
The deviation from the center position O ₁ of 3 measured by the number of pixels the center position O ₁ accurately detected, is obtained as an error measurement through the image processing unit 35, said error value measurements The apparatus main body 11 It is converted into a distance (coordinate value as a shift amount) by the provided CPU.

The converted distance (coordinate value as a shift amount) is grasped as a mechanism error between the X-axis arm 12 and the Y-axis arm 13 and is stored and held in a memory provided in the apparatus main body 11.

Thus, the lower position measuring camera 2
After the error measurement of the position measurement camera 6 and the upper position measurement camera 16 is completed, the position measurement camera 26 and the movable body 26 on the side of the movable body 24 which are paired based on the respective error data acquired separately. Correction is performed based on the relationship between the actual mounting position with the position measuring camera 16 on the side 14 and the position of the theoretical coordinates to be used as a reference, and the processing ends.

For this reason, the same reference mark 53 formed by the through hole 54 can be used in common to measure an error in the mounting position between the upper position measuring camera 16 and the lower position measuring camera 26. So, the camera for position measurement 1
It is possible to accurately grasp an error between the mounting positions of the inspection probes 6 and 26, and to eliminate an error factor in the positioning control of the inspection probes 15 and 25 when actually performing the substrate inspection.

Moreover, since the through hole 54 is used as the reference mark 53 in the substrate 51 of the present invention, the luminaires 18 and 28 are applied to the peripheral regions on both the front and back surfaces including the inner peripheral surface 55 of the through hole 54.
Irradiation light from the light source reaches the lens surfaces 17 and 27 as reflected light, whereas irradiation light into the through hole 54 passes without being reflected. For this reason, the position measurement cameras 16 and 2
In No. 6, the position of the reference mark 53 formed of the through hole 54 can be photographed under a clear contrast image, and correct correction processing can be performed.

The above has been a description of preferred embodiments of the present invention, and the specific contents are not limited to the above description. For example, in the illustrated example, an example is shown in which a pair of movable bodies 14 and 24 arranged in a pair at the top and bottom are arranged, and one position measurement camera 16 or one position measurement camera 26 is used. , Multiple Ys on the same X-axis arm
A plurality of position measuring cameras can be installed by disposing the shaft arm. In this case, the series of processes shown in FIG. 4 is also performed a plurality of times. Further, a movable body may be arranged on the side of the X-axis arm so that the movable body can move on the side of the Y-axis arm along the X-axis arm. Further, the mechanism error of the upper position measuring camera 16 may be detected first, and then the mechanism error of the lower position measuring camera 26 may be detected.

[0032]

As described above, according to the present invention, since the same through hole provided in the substrate is used as a reference mark, either the upper position measuring camera or the lower position measuring camera can be used. Also, the position of the fiducial mark can be accurately photographed, and the error between the two camera mounting positions can be correctly grasped.

Therefore, when actually performing the board inspection, it is possible to eliminate the error factors in the positioning control of the inspection probe and to perform a more accurate measurement inspection.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration example of a main part of a double-sided board inspection apparatus provided for carrying out the present invention.

FIG. 2 is a plan view corresponding to FIG. 1;

FIG. 3 is a block diagram showing an example of a drive system of a position measuring camera according to the present invention.

FIG. 4 is a flowchart illustrating an example of a processing procedure according to the present invention.

FIG. 5 is an explanatory diagram showing an example of an arrangement relationship between a substrate and a camera for position measurement according to the present invention.

FIG. 6 is a plan view showing a configuration example of a main part of a substrate used in the present invention.

FIG. 7 is an explanatory diagram showing an example of a conventional method adopted for accurately bringing an inspection probe pin into contact with a predetermined position of a double-sided printed wiring board as a substrate to be inspected.

FIG. 8 is an explanatory view showing an arrangement relationship between one-side reference marks formed on the front surface of a conventionally used dedicated dummy substrate and other-side reference marks formed on the back surface.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Dedicated dummy board 1a Front surface 1b Back surface 2 Plate surface 3 One-side reference mark 4 Other-side reference mark 5 Non-reflective surface 6,8 Position measurement camera 7,9 Lens surface 11 Device body 12,22 X-axis arm 13,23 Y Axis arm 14, 24 Movable body 15, 25 Inspection probe pin 16, 26 Position measuring camera 17, 27 Lens surface 18, 28 Illumination device 19, 29 Servo motor 31 Holder 32 Position fixing reference point 35 Image processing means 51 Substrate 51a Plate surface 52 Inspection substrate 53 Reference mark 54 Through hole 55 Inner peripheral surface 56 Reflection surface 57 Dedicated dummy substrate O ₁ Center position of reference mark

Claims (2)

[Claims] 1. A substrate having, as a reference mark, a through-hole provided with a reflection surface in a peripheral area on both front and back surfaces including at least an inner peripheral surface thereof is fixed in an apparatus main body, and is mounted with a lens surface facing a plate surface direction. One or more movable bodies that are provided with a position measuring camera and that can be controlled and moved in the vertical and horizontal directions freely are arranged separately in an arrangement relationship in which the pair is opposed to each other in both up and down directions of the substrate, One of the position measuring cameras in the pair of movable bodies is moved to a position of a theoretical coordinate to be a predetermined reference, and is irradiated with light. Measure the error of the actual mounting position of the camera with respect to the theoretical coordinates in relation to the optical image, under the situation where the illumination light of one of the position measurement cameras does not interfere, the other of the pair of movable bodies The camera for position measurement is moved to the position of the theoretical coordinates to be a predetermined reference and irradiated with light, and at that time, in relation to the reflected light image from the reference mark side taken with respect to the theoretical coordinates, The error of the actual mounting position of the camera is measured, and the theoretical coordinates of the theoretical mounting position to be used as a reference are set based on the actual mounting positions of the cameras for measuring the positions of the movable bodies that are paired based on the respective error data acquired separately. A method for correcting a mounting position of a position measuring camera in a double-sided board inspection apparatus, wherein the correction is performed in relation to a position. 2. The double-sided board inspection according to claim 1, wherein the board is either a board to be inspected, which is a double-sided printed wiring board, or a dedicated dummy board separately prepared as a reference. A method for correcting a mounting position of a camera for position measurement in a device.