JP2000321025A - Device and method for detecting movement error of processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the movement error of a processor relatively easily and inexpensively detectable with appropriate accuracy by finding the 'deviation amount' of the processor containing each behavior. SOLUTION: A movement error detecting device which detects the movement error of a processor that performs prescribed processing at a processing position EP is provided with reference patterns PR formed along the moving direction of a plotting state 5 near both edge sections of the stage 5 on both side of the moving direction of the stage 5 with respect to a processing section, two alignment scopes 33 and 35, an arithmetic means which photographs the reference patterns PR and finds the deviation amounts of the patterns PR with respect to the alignment scopes 33 and 35 at each moving position. The device is also provided with a storing means which stores the deviation amount of each reference pattern PR by correlating the amounts to the moving positions. Therefore, the deviation amounts of the patterns PR containing such behaviors as the pitching, yawing, rolling, etc., can be detected by finding the deviation amounts while the plotting stage 5 is moved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movement error detecting apparatus and method for a processing apparatus for performing a predetermined processing on a processing target such as a printed circuit board, and more particularly, to a method for relatively moving a mounting table and a processing unit. The present invention relates to a technique for detecting a movement error generated at the time of the movement.

[0002]

2. Description of the Related Art As a conventional apparatus of this kind, for example, there is a printed circuit board manufacturing apparatus. This device is equipped with a drawing stage on which a printed circuit board is placed, and a processing unit which deflects and irradiates the drawing stage with a laser beam at a predetermined processing position, and directly draws a required pattern on the substrate with the laser beam. Is what you do. The drawing stage is mounted on a linear motion guide and is moved with respect to the processing unit by a feed screw connected to a motor shaft.

In such an apparatus, there is a problem of an error caused by the movement of the drawing stage. In other words, even if the motor is driven to move the drawing stage to move the desired position of the substrate to the processing position, the moving distance is actually shorter or longer than that distance, and the desired position of the substrate is processed. A situation occurs where the position cannot be matched. The main causes of such movement errors are “rolling” around the feed screw, “yawing” occurring in the movement direction on the drawing stage surface, and “pitching” occurring in the movement direction on a plane perpendicular to the drawing stage surface. It is each behavior of.

Since these behaviors cannot be completely eliminated due to the structure of the apparatus, they are measured to detect a movement error at a movement position, and a sub-scan is performed to correct a driving amount of a motor based on the movement error. Generally, correction of main scanning for correcting laser deflection is performed. For example, rolling, yawing, and pitching are independently measured using a measuring device such as an autocollimator or a laser length measuring device (first configuration). On the other hand, a drawing machine, a stepper, or the like, which is more expensive than the above-described apparatus, is configured to perform correction while measuring a movement error in a movement direction or a direction perpendicular to the movement direction with a laser length measuring device in real time. 2).

[0005]

However, the prior art having such a structure has the following problems. That is, in the first configuration, it is possible to independently measure the above behavior, but what is required is a movement error according to the movement position, not each behavior. Therefore, it is necessary to determine the movement error based on each behavior,
It is difficult to obtain a complex movement error in which a plurality of behaviors are entangled.

[0006] On the other hand, in the second configuration, the movement error can be accurately obtained. However, in addition to the problem that the system becomes considerably complicated and the apparatus becomes extremely expensive, in addition to the above problem, the accuracy is higher than the purpose. There is also a problem that it becomes over specification.

The present invention has been made in view of such circumstances, and based on photographing a reference pattern on a mounting table by photographing means, obtains and compares a "shift amount" including each behavior. It is an object of the present invention to provide a movement error detection device of a processing device which can detect a movement error with a simple, inexpensive and moderate accuracy.

[0008]

The present invention has the following configuration in order to achieve the above object. That is, the movement error detection device of the processing device according to claim 1 is
In a movement error detection device of a processing apparatus that relatively moves a mounting table on which a processing target is mounted and a processing unit and performs a predetermined process on the processing target at a processing position, A reference pattern formed along the movement direction near both ends on the surface of the mounting table with respect to the movement direction relative to the processing unit, and at least two reference patterns arranged corresponding to the reference pattern. An operation for photographing a reference pattern with the two photographing means while relatively moving the photographing means and the mounting table and the processing unit, and calculating a shift amount of each reference pattern with respect to each photographing means at each moving position. Means,
Storage means for storing a shift amount of each of the reference patterns in association with a movement position.

According to a second aspect of the present invention, in the moving error detecting device for a processing device according to the first aspect, the photographing means is disposed near a processing position. It is characterized by the following.

According to a third aspect of the present invention, there is provided a method for detecting a movement error of a processing apparatus, wherein a mounting table on which a processing object is mounted and a processing unit are relatively moved, and the processing unit is moved to a processing position with respect to the processing object. In the method for detecting a movement error of a processing apparatus that performs a predetermined process, the processing unit is formed along the moving direction near both ends on the surface of the mounting table with the relative moving direction between the mounting table and the processing unit interposed therebetween. Photographing the reference pattern obtained by moving the mounting table and the processing unit relative to each other by at least two photographing means provided corresponding to the reference pattern; The method includes the steps of: obtaining a shift amount of each reference pattern with respect to the means; and storing the shift amount of each reference pattern in association with a movement position.

[0011]

The operation of the first aspect of the invention is as follows. The mounting table and the processing unit are relatively moved to photograph the reference pattern on the mounting table surface by the two photographing means, and the shift amount of each reference pattern with respect to each photographing means at each moving position is calculated by the calculating means. . The “shift amount” is obtained by projecting a behavior such as pitching, yawing, rolling, and the like onto the photographing means in a plane. This "shift amount"
By storing the object and each moving position in the storage unit in association with each other, it is possible to detect a moving error according to the moving position when the processing is performed with the processing target placed on the mounting table.

Note that the storage means includes devices such as a plotter and a CRT, in addition to a semiconductor memory and a hard disk device.

According to the second aspect of the present invention, since the processing is actually performed on the object to be processed at the processing position, the closer the photographing means is to the position, the smaller the movement error at the processing position. Detection accuracy can be improved.

According to the third aspect of the present invention, first, after the step of photographing the reference pattern by the photographing means, the shift amount of each reference pattern with respect to the photographing means is obtained, and then the shift amount of each reference pattern is calculated. By storing in association with the movement position and storing the object to be processed on the mounting table, a movement error can be detected according to the movement position.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view for explaining the outline of a printed circuit board manufacturing apparatus, FIG. 2 is a detailed plan view, and FIG. 3 is a detailed side view.

On the upper surface of the base 1, a pair of guide rails 3
Are arranged, and between those guide rails 3,
A feed screw 9 rotated by a servomotor 7 is provided. The drawing stage 5 is screwed to the feed screw 9 at a lower portion thereof. The drawing stage 5 includes, in order from the bottom, a rotation mechanism 11 for rotating around a vertical z-axis and a lifting mechanism 13 for lifting and lowering in the vertical z-direction.
A mounting table 15 for mounting a printed circuit board (processing object) by suction is provided at the uppermost portion.

Drawing stage 5 corresponding to the mounting table of the present invention
A reference mask RM on which a reference pattern PR is formed is arranged so that its upper left corner coincides with a reference position (the upper left corner of the mounting table 15 although not shown). Have been. The reference pattern PR has a cross shape so that the processing described later can be easily performed.
Are formed near both ends of the reference mask RM.

In the y direction (sub-scanning direction) in which the drawing stage 5 is moved by the drive of the servomotor 7, the drawing laser beam LB is deflected in the x direction (main scanning direction) at the processing position EP. A processing unit 21 for irradiating downward is provided. The processing section 21 is disposed above the base 1 by a gate-shaped frame. When the servomotor 7 is driven, the drawing stage 5 advances below the processing section 21.

An alignment scope unit 31 is arranged on the base 1 so as to cover the upper part of the drawing stage 5 at the standby position shown in FIG. The alignment scope unit 31 includes four alignment scopes 33, 35, 37, and 3 that can move independently in a horizontal plane.
9 is provided. Each alignment scope 33, 35,
37, 39 are CCD cameras 33a, 35a, 37a,
39a and lens portions 33b, 35b, 37b, 39b. These alignment scopes 33, 3
5, 37, and 39 originally measure the positions of the alignment holes at the four corners of the printed circuit board mounted on the drawing stage 5 to determine the amount of positional displacement of the board mounted on the drawing stage 5, and Although it is used for correcting the displacement, in the present invention, two alignment scopes 33 and 35 provided on the processing position EP side are used as described later.
Is also used to detect a movement error of the drawing stage 5.

The two alignment scopes 33 and 35 described above correspond to a photographing unit in the present invention.

Referring to the block diagram of FIG. CCD camera 3 for each alignment scope 33, 35, 37, 39
3a, 35a, 37a, and 39a are all connected to the image processing unit 41, where each video signal is processed to calculate the position of the center of gravity and calculate the "shift amount". Also,
The image processing unit 41 includes a keyboard 43 for instructing the start of processing and the like, and each of the alignment scopes 33, 35, 3
A CRT 45 for displaying images captured by the cameras 7 and 39 and displaying processing contents is connected.

It is the system controller 47 that controls the entire apparatus. Here, the main scanning control circuit 49
, A sub-scanning control circuit 51, an error table storage unit 53, and the like. At the time of drawing, the system control unit 47 controls a beam position control circuit 57 that controls the position of the laser beam LB in the x direction based on the raster data sequentially sent from the raster conversion circuit 55 to the main scanning control circuit 49. The beam position control circuit 57 includes a system control unit 47
Electronic shutter 5 based on instructions from the
9 is controlled. The X-axis sensor 61 detects an optical signal from an X linear scale (not shown) disposed in the x direction,
This is for measuring the deflection distance of the laser beam LB in the main scanning direction. The signal from here is sent to the signal processing circuit 63
After being appropriately processed by the system controller 47, the signal is taken into the system controller 47, and a clock pulse to the drive circuit 65 of the sub-scanning control circuit 51 is generated based on this signal.

The servo motor 7 of the sub-scanning control circuit 51
Driven by the drive circuit 65 based on a clock pulse generated in accordance with the main scanning of the laser beam LB. Thereby, the drawing stage 5 is moved in the y-direction (sub-scanning direction). The moving position is detected by a Y-axis sensor 67 that detects an optical signal from a Y linear scale (not shown), converted into a signal corresponding to the moving position by a signal processing circuit 69, and provided to the system control unit 47. The system control unit 47 feeds back the drive of the servomotor 7 according to the signal.

When the system controller 47 moves the drawing stage 5 on which the reference mask RM is provided, the error table storage 53 receives data from the two alignment scopes 33 and 35 provided on the processor 21 side. The "shift amount" of the reference pattern PR obtained by the image processing unit 41 processing the video signal of "1" is stored as an "error table" in association with each movement position.

The image processing section 41 described above corresponds to the calculating means of the present invention, and the error table storage section 53 corresponds to the storing means of the present invention.

The reference mask RM in this embodiment is shown in FIG.
It is configured as shown in FIG. That is, along the y direction
And a long line is drawn at predetermined intervals in the x direction.
Along the short line, n lines are drawn. As described above,
The screen RM is taken according to the reference position of the mounting table 15.
Because, for example, for each reference pattern PR
The coordinates are (x₁, Y₁), ... (x₁, Y_Two),
...... (x₁, Y _n) And (x_m, Y₁),…
... (x_m, Y_Two), ... (x_m, Y_n).

Further, as shown in FIG. 6, the above-mentioned "displacement amount" refers to the intersection between the field center C of the field image V captured by each of the CCD cameras 33a and 35a and the intersection of the long line and the short line of the reference pattern PR. The displacement is obtained for the x direction (Δx) and the y direction (Δy). Therefore, when the “shift amount” is “0” in both the xy directions, the intersection of the reference pattern PR in FIG.
The error table in the error table storage unit 53 described above is
The above Δx and Δy are movement errors associated with the respective movement positions, that is, the drive amounts of the servo motor 7 driven so that the intersection of the reference pattern PR coincides with the center of the field of view C by design.

As shown in FIGS. 2 and 3, the two alignment scopes 33 and 35 are moved y from the processing position EP.
Are separated by an interval L in the direction. Since the processing in this device is performed at the processing position EP, the closer the processing position EP is to the processing position EP, the higher the detection accuracy of the movement error at the processing position EP can be. Therefore, the interval L is changed to the processing position E.
The closer to P, the more accurate the correction at the processing position EP.

Next, a process of detecting a movement error will be described with reference to the flowchart of FIG.

First, with the drawing stage 5 at the standby position, each alignment scope 33 is set such that the x direction of the field center C of each of the two alignment scopes 33 and 35 coincides with the long line of the reference pattern PR. , 35 are adjusted in advance.

Step S1 The servo motor 7 is driven so that the drawing stage 5 moves by a predetermined distance. By this driving, the reference pattern PR
Are located in the field of view.

Step S2 Image processing is performed on the photographed reference pattern PR,
The “shift amount” (Δx, Δy) as shown in FIG. 6 is obtained by calculation for each of the reference patterns PR.

Step S3: The drawing stage 5 is moved by an interval of each short line of the reference pattern PR. Normally, this movement causes the next intersection of the reference pattern PR to be located within the field of view of each of the alignment scopes 33 and 35.

Step S4 The image in the field of view is processed to determine whether or not the reference pattern PR exists. If there is, the process returns to step S2 to repeat the above-mentioned process. If not, the process proceeds to step S5. .

Step S5 An error table is generated by associating each "deviation amount" obtained as described above with each movement position, and this is stored in the error table storage unit 53.

The error table thus generated is drawn on the drawing stage 5 so that the intersection of the two reference patterns PR coincides with the center position of the alignment scopes 33 and 35.
Is the “shift amount” of the intersection with respect to each center position when is moved. This “shift amount” is determined by the drawing stage 5
Are generated when the object is moved, that is, rolling, yawing, pitching, and the like are projected onto the alignment scopes 33 and 35 in a plane.

Therefore, when the printed circuit board is set on the drawing stage 5 to process the product and the drawing process is performed, the error table including the shift amount is read out to move the drawing stage 5 in accordance with the moving position. An error can be detected. Therefore, the movement error of the drawing stage 5 at the processing position EP is corrected by controlling the drive amount of the servo motor 7, the θ-axis drive mechanism (not shown), the beam position control circuit 57, and the like according to the “shift amount”. Can be.

In addition, since it is only necessary to generate an error table prior to the processing of the product, it can be constructed at a lower cost and has a modest cost as compared with a conventional example in which correction is performed in real time while measuring with a laser length measuring device. The movement error can be detected with high accuracy. Further, if the error table is periodically collected, the movement error can be accurately detected over a long period of time, and the processing can be performed accurately.

The present invention can be modified as follows.

(1) The reference pattern formed on the reference mask RM is not limited to the long and short crosses described above, but may be any shape as long as the center of gravity of the pattern is determined. Is also good.

For example, a circular shape may be formed at a predetermined interval as shown in FIG. 8A, or a long line and a short line may be shifted from each other as shown in FIG. 8B. Even if formed as described above, the center of gravity of the circle or the center of the short line can be obtained by image processing, so that the "shift amount" can be easily obtained.

Further, the reference pattern PR may not be formed only at both ends but may be formed over the entire surface of the reference mask RM to use only necessary portions.

(2) Using the reference pattern PR as the reference mask RM
Instead of being formed on the mounting table 15, it may be formed directly on the upper surface of the mounting table 15.

(3) The storage means of the present invention is not limited to a memory such as the error table storage unit 53, but plots and displays each moving position and the amount of displacement, or displays by a bright line. Plotter and CR
It may be T.

(4) If at least two photographing means (alignment scopes 33 and 35) are provided across the moving direction, a displacement amount including a behavior such as rolling can be obtained, so three or more photographing means are used. You may make it.

(5) In the above-described embodiment, the processing unit 21 is fixed and the drawing stage 5 moves. However, the present invention can be applied to a configuration in which the processing unit 21 moves.

(6) In the above-described embodiment, a printed circuit board manufacturing apparatus has been described as an example, but the present invention is not limited to such an apparatus. For example, a PDP board manufacturing apparatus or a precision measuring apparatus Even if it is, it is applicable.

[0048]

As is apparent from the above description, according to the first aspect of the present invention, the "shift amount" in which the behaviors such as rolling, yawing, and pitching are projected onto the photographing means in a plane. And each moving position are stored in the storage means in association with each other, so that the configuration can be performed at a lower cost than in the conventional example in which correction is performed in real time while measuring with a laser length measuring device, and moving with appropriate accuracy. An error can be detected. Therefore, when processing is performed with the processing target placed on the mounting table, an error can be corrected according to the movement position, and processing can be accurately performed on the processing target.

According to the second aspect of the present invention, by arranging the photographing means near the processing position,
The detection accuracy of the movement error at the processing position can be improved. Therefore, the correction at the processing position can be performed more accurately.

According to the third aspect of the present invention, first, the reference pattern is photographed by the photographing means, the shift amount of each reference pattern is obtained, and the shift amount of each reference pattern is stored in association with the moving position. By doing so, the movement error can be detected with appropriate accuracy. Therefore, when the processing is performed with the processing target placed on the mounting table, the correction can be made according to the moving position, and the processing can be accurately performed on the processing target.

[Brief description of the drawings]

FIG. 1 is a perspective view for providing a brief description of a printed circuit board manufacturing apparatus according to the present invention.

FIG. 2 is a detailed plan view of the printed circuit board manufacturing apparatus.

FIG. 3 is a detailed side view of the printed circuit board manufacturing apparatus.

FIG. 4 is a block diagram of a printed circuit board manufacturing apparatus.

FIG. 5 is an explanatory diagram of a reference pattern formed on a reference mask.

FIG. 6 is a schematic diagram showing a visual field image of a CCD camera.

FIG. 7 is a flowchart illustrating a process of detecting a movement error.

FIG. 8 is a diagram showing a modified example of the reference pattern formed on the reference mask.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base 3 ... Guide rail 5 ... Drawing stage (mounting table) 7 ... Servo motor 9 ... Feed screw PR ... Reference pattern RM ... Reference mask EP ... Processing position LB ... Laser beam 21 ... Processing parts 33, 35, 37, 39: Alignment scope (imaging means) 41: Image processing section (computing means) 53: Error table storage section (storage means)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroyuki Shirota 4-chome Tenjin Kitamachi 1-chome, Horikawa-dori-Terauchi, Kamigyo-ku, Kyoto F-term (reference) 2F065 AA17 AA20 BB28 CC00 FF01 FF04 FF67 JJ03 JJ05 JJ26 MM03 PP12 QQ23 QQ31 SS02 SS13 2H097 AA03 AB05 CA17 KA13 KA20 LA09 5F046 AA06 BA07 CA03 CC01 DB04 DC12 EA02 EB03 EC02 ED02 FA10 FB02 FC04

Claims (3)

[Claims] 1. A movement error detection device for a processing apparatus for relatively moving a mounting table on which a processing target is mounted and a processing unit and performing predetermined processing on the processing target at a processing position, Sandwiching the relative movement direction between the mounting table and the processing unit,
A reference pattern formed along the moving direction near both ends on the surface of the mounting table, at least two photographing means arranged corresponding to the reference pattern, the mounting table and the processing unit, Computing means for photographing a reference pattern with the two photographing means while relatively moving the image, and calculating a shift amount of each reference pattern with respect to each photographing means at each moving position; and moving a shift amount of each reference pattern. A movement error detection device for a processing device, comprising: storage means for storing in association with a position. 2. The moving error detecting device for a processing device according to claim 1, wherein said photographing means is disposed near a processing position. 3. A moving error detecting method for a processing apparatus, wherein a mounting table on which a processing target is mounted and a processing unit are relatively moved and a predetermined processing is performed on the processing target at a processing position. A reference pattern formed along the moving direction near both ends on the surface of the mounting table with the relative movement direction between the mounting table and the processing unit interposed therebetween, the reference pattern being disposed corresponding to the reference pattern. A step of photographing while relatively moving the mounting table and the processing unit by at least two photographing means; a step of calculating a shift amount of each reference pattern with respect to each photographing means at each movement position; Storing a displacement amount of the reference pattern in association with the movement position.