JP3842353B2 - X-ray image intensifier misalignment correction apparatus and printed circuit board drilling apparatus including the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an axis misalignment correction apparatus for correcting an axis misalignment between an input image and an output image of an X-ray image intensifier, and a printed circuit board drilling apparatus using the same.
[0002]
[Prior art]
An X-ray image intensifier is composed of a fluorescent screen that converts X-rays into light, and a photoelectron emitter, an electron multiplier, and an electron tube provided with a fluorescent plate in close contact with each other. When an (input image) is incident, photoelectrons are emitted, and the photoelectrons are multiplied by an electron multiplier and irradiated onto a fluorescent screen to output a visible subject image (output image). Since this X-ray image intensifier has a function of amplifying a weak subject X-ray image at a high multiplication factor, it is used for medical fluoroscopy, industrial nondestructive inspection, and the like.
[0003]
[Problems to be solved by the invention]
However, this X-ray image intensifier is affected by changes in the surrounding environment, such as changes in temperature and magnetic field, so that the X-ray image intensifier is incident on the electron emitter and the subject image reproduced on the fluorescent screen. There is a problem that a so-called axis deviation phenomenon occurs in which the output position of the subject shifts, and the absolute position of the subject cannot be measured with high accuracy.
[0004]
For example, in a printed circuit board drilling apparatus that measures the hole position of a printed circuit board using an X-ray image intensifier and performs a hole drilling process at the measured position, There is a problem in that the drilling position and the measured drilling position are deviated and the drilling is performed based on the measured drilling position, so that the machining accuracy is lowered and fluctuated.
[0005]
Conventionally, as a technique for solving such problems, there is one disclosed in Japanese Patent Laid-Open No. 5-8107. This corrects the temperature drift between the center of the X-ray camera and the center of the drill over time. That is, the temperature drift is measured in advance along time and corrected based on the measured data. However, although this conventional technique can correct only for a specific temperature pattern, it has a problem that accurate correction cannot be performed when the temperature pattern changes. For example, if the temperature drift is measured in summer and the correction is made based on the measured data, accurate correction cannot be performed in winter. In addition, this conventional technique cannot correct a drift due to a magnetic field.
[0006]
The present invention has been made in view of such a problem. An axis deviation correction apparatus for correcting an axis deviation between an input image and an output image in an X-ray image intensifier, and the axis deviation correction apparatus are provided. It is an object of the present invention to provide a printed circuit board drilling device that can realize high-precision drilling by providing the printed circuit board.
[0007]
[Means for Solving the Problems]
In order to achieve such an object, the X-ray image intensifier axial misalignment correction apparatus of the present invention includes a calibration reference mark provided at a predetermined position of the X-ray incident end of the X-ray image intensifier, An image in which the position of the center of gravity of the image of the calibration reference mark obtained by measuring the calibration reference mark with an X-ray image intensifier is obtained, and the position of the center of gravity is used as a reference position for measuring the measurement target. And a processing means.
[0008]
Further, the printed circuit board drilling device of the present invention, an X-ray image intensifier provided with a calibration mark at a predetermined position of the X-ray incident end, and a punching means provided in the X-ray image intensifier, Position of the center of gravity of the image of the calibration reference mark obtained by measuring the calibration reference mark with the X-ray image intensifier, moving means for integrally moving the X-ray image intensifier and the punching means Image processing means for obtaining a first center of gravity position of the image of the calibration reference mark by the image processing means, and drilling a hole at an appropriate position of the calibration printed board by the punching means, The moving means so as to match an image of the hole obtained by measuring the hole with an X-ray image intensifier to the position of the first center of gravity. A reference hole provided in advance on a printed circuit board to be processed, with the movement distance when the X-ray image intensifier and the punching means are moved as an offset distance between the X-ray image intensifier and the punching means. When drilling a hole that matches the opening mark, the image processing means obtains a second barycentric position of the image of the calibration reference mark, and the X-ray image intensifier applies the reference hole opening mark. The X-ray image intensifier and the punching means are moved by the moving means so that the image of the reference punch mark obtained by measurement matches the second center of gravity position, and the offset distance is further moved. The moving means is controlled to move and a hole is formed in the printed circuit board by the punching means.
[0009]
Embodiment
An embodiment of the present invention will be described with reference to the drawings. This embodiment relates to a printed circuit board drilling device provided with an X-ray image intensifier axial deviation correction device.
[0010]
FIG. 1 is a block diagram showing the configuration of this printed circuit board drilling apparatus. In FIG. 1, an X-ray image intensifier 4 is arranged opposite to the X-ray emission end of the X-ray source 2 to A video camera 6 is fixed so as to face a fluorescent plate (not shown) provided in the tensiifier 4. Further, in the vicinity of the X-ray image intensifier 4, a drilling device 14 having drill teeth 12 for drilling holes in the printed circuit board 10 placed on the mounting table 8 is arranged. These X-ray source 2, X-ray image intensifier 4, video camera 6 and drilling device 14 are fixed to an XY stage 16 that is a moving means, and the XY stage 16 moves horizontally along the XY coordinates, The measurement position of the printed board 10 by the X-ray image intensifier 4 and the drilling position of the printed board 10 by the punching device 16 can be adjusted.
[0011]
Furthermore, an image processing unit 18, an XY stage driving unit 20, an operation unit 22, and a display unit 24 each including a microcomputer system are provided. The image processing unit 18 performs processing for correcting an axial deviation of the X-ray image intensifier 4 described later by performing image processing on an image signal output from the video camera 6 according to a predetermined program. The XY stage driving unit 20 moves the measurement position of the printed circuit board 10 by the X-ray image intensifier 4 by moving the XY stage 16 according to a command from the image processing unit 18, or the punching device 14 for the printed circuit board 10. Drive control such as moving the drilling position is performed. The operation unit 22 includes a keyboard or the like for the user to input a desired instruction to the image processing unit 22, and the display unit 24 displays the image processing result of the image processing unit 18 or is transferred from the video camera 6. A display or the like for displaying a reproduced image based on the image signal is provided.
[0012]
As shown in FIG. 2, the X-ray incident surface of the X-ray image intensifier 4, that is, a fluorescent screen provided in the X-ray image intensifier 4 for converting X-rays into light, and the photosensitive property in close contact therewith. A plurality of calibration reference marks M1 to M4 arranged at equal intervals from the center Q are fixed to the X-ray incident window 26 located in front of the electron emission surface of the electron emission surface, and these calibration reference marks M1 to M4 are fixed. Is made of a material having a low X-ray transmittance, such as lead or tungsten. In this embodiment, four marks M1 to M4 are provided. However, the number of marks M1 to M4 is not limited to four, and a plurality of points symmetrical with respect to the center Q of the X-ray incident window 26 are provided. A pair of marks may be provided, or may be provided at a predetermined position without using the center Q as a reference. Further, the axis center of the drill tooth 12 is positioned with respect to the center Q with a mechanical offset of X _{OF in} the X coordinate direction and Y _{OF in} the Y coordinate direction.
[0013]
Next, the operation of correcting the misalignment of the X-ray image intensifier 4 in the printed circuit board punching device having such a configuration will be described with reference to the flowchart of FIG.
[0014]
After the system power is turned on in step S100, the apparatus is activated, and in steps S102 to S105, the user places the calibration printed circuit board 10a on the mounting table 8, and the perforation device 14 forms calibration holes in appropriate portions. 28 is opened, and the X-ray image intensifier 4 is moved close to the calibration hole. When the hole is drilled, the X-ray image intensifier 4 is affected by a change in temperature or magnetic force, causing an axis shift in the X-ray image intensifier 4 as shown in FIG. The mark images M1 ′ to M2 ′ are displayed on the fluorescent plate at positions shifted from the actual calibration reference marks M1 to M2. That is, as shown in FIG. 4B showing a cross section of the main part, the mark images M1 ′ to M2 ′ are displayed at positions shifted from the center Q of the actual calibration marks M1 to M4 and output from the video camera 6. The image signal is transferred to the image processing unit 18 and stored in a frame memory or the like.
[0015]
Next, in step S106, the image processing unit 18 determines the positions (x ₀₁ , y ₀₁ ), (x ₀₂ , y ₀₂ ), the positions (x ₀₁ , y ₀₁ ), (x ₀₂ , y ₀₂ ) of the respective mark images M1 ′, M2 ′, M3 ′, M4 ′ on the xy coordinates. _Find (x ₀₃ , y ₀₃ ), (x ₀₄ , y ₀₄ ). Here, the xy coordinates correspond to the pixel arrangement within the visual field range of the video camera 6 and are determined based on the storage address set in the frame memory. Further, in step S108, by calculating the following equations (1-a) and (1-b) based on the position data on the xy coordinates, the center-of-gravity positions G _{1 of} these mark images M1 ′ to M4 ′ are obtained. The coordinates (x _g1 , y _g1 ) are obtained.
[0016]
x _g1 = (x ₀₁ + x ₀₂ + x ₀₃ + x ₀₄ ) / 4 (1-a)
y _g1 = (y ₀₁ + y ₀₂ + y ₀₃ + y ₀₄ ) / 4 (1-b)
Next, in step S110, the XY stage 16 is moved, and the center of the image 28 'of the calibration hole 28 displayed on the fluorescent plate of the X-ray image intensifier 4 is positioned as shown in FIGS. In step S112, the distance X _OF ′ moved in the X direction of the XY stage 16 and the distance Y _OF ′ moved in the Y direction are obtained in step S112, and these distances are obtained. X _OF ′ and Y _OF ′ are stored as an offset distance between the X-ray image intensifier 4 and the drill tooth 12.
[0017]
Thus, by the pre-processing of steps S102 to S112, the interval between the mounting position of the X-ray image intensifier 4 and the mounting position of the drill teeth 12 is measured in advance, and the drilling process to the printed circuit board to be originally processed is This is performed in the next steps S114 to S124.
[0018]
In step S114, a printed board 10b to be processed by the user is placed on an appropriate position on the mounting table 8, and a mark (hereinafter referred to as a reference hole drilling) for indicating a drilling position printed in advance on the printed board 10b. In step S115, the X-ray image intensifier 4 is moved near the reference hole punch mark.
[0019]
In response to this instruction, in step S116, the X-ray image intensifier 4 and the video camera 6 again measure the calibration reference marks M1 to M4, and the image processing unit 18 obtains the mark images M1 ″ to M4 obtained by this measurement. ”(X ₁₁ , y ₁₁ ), (x ₁₂ , y ₁₂ ), (x ₁₃ , y ₁₃ ), (x ₁₄ , y ₁₄ ) on the xy coordinates at the present time are obtained, and in step S118, Based on the position data on the xy coordinates, the following expressions (2-a) and (2-b) are performed to obtain the coordinates (x _g2 , y) of the gravity center position G ₂ of the mark images M1 ″ to M4 ″. _g2 ).
[0020]
x _g2 = (x ₁₁ + x ₁₂ + x ₁₃ + x ₁₄ ) / 4 (2-a)
y _g2 = (y ₁₁ + y ₁₂ + y ₁₃ + y ₁₄ ) / 4 (2-b)
The reference marks M1 to M4 are again measured in this way because the ambient temperature and magnetic field of the X-ray image intensifier 4 change between the time when the offset distances X _OF 'and Y _OF ' are obtained and the present time. because sometimes, in order to confirm the center of gravity position G ₂ of the mark image M1 "through M4" in the axial displacement state at the moment of X-ray image intensifier 4 immediately before performing boring.
[0021]
Next, in step S120, as shown in FIG. 6 (a) (b), so as to match the mark image C 'of the reference drilling marks C as measured by X-ray image intensifier 4 to the center-of-gravity position G ₂ The XY stage 16 is driven and controlled.
[0022]
Next, at step S122, as shown in FIGS. 7A and 7B, the XY stage 16 is moved by the offset distances X _OF ', Y _OF '. By this movement processing, the axis center of the drill tooth 12 matches the position of the reference hole mark C.
[0023]
In step S 124, the drilling device 14 is operated to drill a desired hole at the position of the reference hole mark C with the drill teeth 12.
[0024]
As described above, according to this embodiment, the calibration reference marks M1 to M4 are provided in advance in the X-ray incident window 26 of the X-ray image intensifier 4, and the fluorescent plate of the X-ray image intensifier 4 is provided. Since the center of gravity position G ₂ of the projected mark image is obtained and the image C ′ of the target object such as the reference punch mark C is matched with the center of gravity position G ₂ , the X-ray image intensifier 4 changes the temperature. Even if an axis deviation phenomenon is caused by the influence of changes in the surrounding environment such as a magnetic field change or a magnetic field change, the position of the target can be measured based on the xy coordinates corrected for the axis deviation. An excellent effect that the position of the can be accurately measured is exhibited.
[0025]
Even when the position of the X-ray image intensifier 4 as the measuring means and the position of the punching device 14 as the working means are inevitably different, the X-ray image intensities in the processing of the steps S102 to S112. Since the offset distance between the two is obtained in a state in which the axis deviation of the fire 4 is corrected, the offset distance can be obtained with high accuracy, and extremely accurate drilling can be realized.
[0026]
In particular, in the case of a printed circuit board drilling apparatus in which the printed circuit board is kept stationary and the X-ray image intensifier is moved as in this embodiment, the X-ray image intensifier is moved. However, the influence of the surrounding environment can be removed by this axial deviation correction.
[0027]
In this embodiment, an apparatus for drilling a predetermined position on a printed circuit board has been described. However, the axis misalignment correction apparatus of the present invention is not limited to that applied to such an apparatus, and various It has the versatility that it can be widely applied to fields such as position detection and measurement of target objects.
[0028]
8 and 9 show experimental results for demonstrating the effect of this axis deviation correcting apparatus. 8A and 8B show the displacement amount ΔTx in the x-coordinate direction and the displacement amount ΔTy in the y-coordinate direction of the output image with respect to the input image caused by the axis deviation phenomenon when the ambient temperature Ta changes with time. And the displacement amount ΔTCx in the x-coordinate direction after the axis deviation correction and the displacement amount ΔTCy in the y-coordinate direction are compared. FIGS. 9A and 9B show the amount of displacement ΔMx in the x-coordinate direction of the output image with respect to the input image caused by the axis deviation phenomenon when the ambient magnetic field changes by changing the position of the X-ray image intensifier. The displacement amount ΔMy in the y-coordinate direction is compared with the displacement amount ΔMCx in the x-coordinate direction after the axis deviation correction and the displacement amount ΔMCy in the y-coordinate direction.
[0029]
As apparent from these experimental results, the fluctuation amounts ΔTCx, ΔTCy, ΔMCx, and ΔMCy after the axis deviation correction are greatly reduced, so that the influence of temperature fluctuation and magnetic field fluctuation can be eliminated, It was confirmed that the axis deviation of the output image was corrected.
[0030]
【The invention's effect】
As described above, according to the present invention, the centroid position of the image obtained by measuring the calibration reference mark provided at the X-ray incident end of the X-ray image intensifier is obtained, and the centroid position is used as a reference. Because the position of various targets is measured, even if an axis shift phenomenon occurs in the X-ray image intensifier due to changes in the surrounding environment, the position of the target is accurately corrected by correcting this axis shift. Can be measured.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of a printed circuit board drilling device equipped with an X-ray image intensifier axial deviation correction device of the present invention.
FIG. 2 is an explanatory diagram for explaining a calibration reference mark provided in an X-ray image intensifier.
FIG. 3 is a flowchart for explaining the operation of the printed circuit board punching device.
FIGS. 4A and 4B are a main part plan view and a main part cross-sectional view for explaining a positional relationship between a calibration printed circuit board, an X-ray image intensifier, and a punching apparatus, and an axis deviation phenomenon of the X-ray image intensifier.
FIG. 5 is a main part plan view and a main part sectional view for further explaining the positional relationship between the calibration printed circuit board, the X-ray image intensifier, and the punching apparatus, and the axis deviation phenomenon of the X-ray image intensifier. .
FIGS. 6A and 6B are a plan view and a cross-sectional view of a main part for further explaining the positional relationship between the printed circuit board for calibration, the X-ray image intensifier, and the punching apparatus, and the phenomenon of the axis deviation of the X-ray image intensifier. .
FIGS. 7A and 7B are a main part plan view and a main part cross-sectional view for further explaining the positional relationship between the calibration printed circuit board, the X-ray image intensifier, and the punching apparatus, and the axis deviation phenomenon of the X-ray image intensifier. .
FIG. 8 is an explanatory view showing an experimental result for explaining an effect of the axial deviation correction of the present invention with respect to a temperature change.
FIG. 9 is an explanatory diagram showing an experimental result for explaining an effect of the axis deviation correction of the present invention with respect to a magnetic field change.
[Explanation of symbols]
2 ... X-ray source, 4 ... X-ray image intensifier, 6 ... Video camera, 8 ... Mounting table, 10, 10a, 10b ... Printed circuit board, 12 ... Drill tooth, 14 ... Drilling device, 16 ... XY stage, 18 DESCRIPTION OF SYMBOLS ... Image processing part, 20 ... XY stage drive part, 22 ... Operation part, 24 ... Display part, 26 ... X-ray entrance window, M1-M4 ... Calibration reference mark, C ... Reference hole mark.

Claims (2)

A calibration reference mark provided at a predetermined position of the X-ray incident end of the X-ray image intensifier;
A centroid position of the image of the calibration reference mark obtained by measuring the calibration reference mark by the X-ray image intensifier is obtained, and the centroid position is set as a reference position for measuring the measurement target. Image processing means;
An X-ray image intensifier misalignment correction apparatus comprising: An X-ray image intensifier provided with a calibration mark at a predetermined position of the X-ray incident end;
A perforation means attached to the X-ray image intensifier;
Moving means for moving the X-ray image intensifier and the punching means together;
Image processing means for obtaining the position of the center of gravity of the image of the calibration reference mark obtained by measuring the calibration reference mark with the X-ray image intensifier,
A first centroid position of the image of the calibration reference mark is obtained by the image processing means, a hole is drilled at an appropriate position of the calibration printed board by the punching means, and the X-ray image intensifier The moving distance when the X-ray image intensifier and the punching means are moved by the moving means so that the image of the hole obtained by measuring the hole matches the first center-of-gravity position is the X-ray. The offset distance between the image intensifier and the drilling means
When drilling a hole that matches a reference hole mark provided in advance on a printed circuit board to be processed, the image processing means obtains a second center of gravity position of the image of the calibration reference mark, and The X-ray image intensifier is moved by the moving means so as to match an image of the reference hole punching mark obtained by measuring the reference hole punching mark with an X-ray image intensifier. A printed circuit board punching device, wherein a fire and a punching means are moved, and the movement means is controlled to move by the offset distance so that a hole is formed in the printed board by the punching means.

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