JP2503201B2 - Through-hole inspection device - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a double-sided printed board and a multilayer printed board used in electronic equipment, and more particularly to a through-hole inspection device provided in such a printed board. is there.

[Prior art]

Through-holes are formed on the double-sided printed boards and the multilayer printed boards by electrical or chemical plating to electrically connect the printed wirings on the front and back sides formed on those boards and between the printed wirings on each layer. ing. Usually, the plated layer of the through hole is not always in good condition, and defects such as breaks and pinholes often occur in the manufacturing process. Since these defects impair the purpose of connection and impair the reliability of the printed board, it is necessary to inspect such defects in advance.

Conventionally, as a method of inspecting such a defect of a through hole, a roller mask is provided on a printed board provided with a through hole, the printed board is irradiated with light while moving the mask, and the light transmitted through the through hole is divided into two. A so-called through-hole light leakage detection method is used, in which a light receiving element such as a CCD (charge-coupled device) is used for detection, and both detection data are compared to detect a defective portion.

[Problems to be solved by the invention]

In the above-described through-hole inspection device, it is necessary to prepare two light receiving elements, which has a drawback that the inspection device becomes complicated.

The present invention has been made in view of the above-mentioned drawbacks, and an object thereof is to provide a through-hole inspection apparatus capable of detecting a defect in a through-hole with a simple configuration using a single light-receiving element.

[Means for solving problems]

According to the present invention, there is provided a through-hole inspection device for detecting a light leakage pattern of a through-hole provided in a printed board to detect a defect in the through-hole, the printed board being located on one surface of the printed board. A mask means for blocking light incident on the filter board; a filter means located on the other surface of the printed board for attenuating a part of the transmitted light from the printed board; and an image of the light passing through the filter means 1
Image pickup means, an image pickup means located between the image pickup means and the filter means for forming an image of light passing through the filter means on the image pickup means, and defect detection of the through hole from a signal picked up by the image pickup means It is achieved by providing a through-hole inspection apparatus characterized by having a control means for performing control.

[Action]

According to the above means, when light leakage occurs from the through hole, the light leakage can be detected via the image pickup means, and the position of the through hole can be detected by the same image pickup means. It has the function of being able to detect defects in holes.

Example of Invention

 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In this embodiment, a television camera (hereinafter referred to as a TV camera) is used as a single light receiving element, and FIG. 1 shows a schematic perspective view of this embodiment. In the figure, a filter 2 is provided on the upper surface of a double-sided printed board (hereinafter referred to as a printed board) 1 having pattern wiring on both sides and a large number of through holes.
Is provided, and the roller mask 3 is provided on the lower surface. The printed board 1 is configured to be movable on X-axis and Y-axis which are orthogonal to each other by an XY stage (not shown), and the filter 2 adjusts the light intensity, so that the light-transmitting region 2a and the light are attenuated and transmitted. It is composed of three areas, 2b and 2c,
The roller mask 3 is configured to be rotatable around the fulcrum 3a.

Light 4 from a light source (not shown) provided below the printed board 1 is applied to the lower surface of the printed board 1 other than the portion shielded by the roller mask 3, and the light passing through the through holes of the printed board 1 is filtered. Lens 5 through 2
Incident on. For example, the light emitted from the through hole 1a enters the TV camera 7 provided on the focal length of the lens 5 via the optical path 6. The light incident on the TV camera 7 is converted into an electric signal and output to a control circuit provided in a portion not shown.

FIG. 2 is a block diagram of the control circuit, in which the image signal which is an electric signal from the TV camera 7 is the hole position address part 8
, And the hole position address section 8 detects a large number of through hole center positions (addresses) provided in the printed board 1. The detection signal from the hole position address unit 8 is input to the address addition unit 9, and the address addition unit 9 adds the data from the hole pitch address unit 10 in which the pitch of each through hole position is input in advance, and adds the address. The address signal added by the unit 9 is input to the comparison unit 11.

On the other hand, another image signal from the TV camera 7, for example, an image signal of light that has passed through only the filter 2a is input to the light leak address unit 12, and the light leak address unit 12 detects the light leak pattern of the light leak pattern by the TV camera 7. The address signal of the center position is output to the comparison unit 11. The comparing unit 11 compares the two input address signals, and when both the address signals match, outputs a defect signal to detect that there is a defect in the through hole existing at the matched address (position).

In the through-hole inspection device configured as above,
The operation will be described with reference to FIGS. 3 (a) and 3 (b).

FIG. 3A shows the filter 2 imaged by the TV camera 7.
It is an image of the upper surface. In the figure (a), X
The axes Y and Y are the same as the X and Y directions, which are the moving directions of the XY stage, and the image 14 has five through holes 1b to 1f in the region 2b of the filter 2. , Four through holes 1g to 1j are present in the area 2a of the filter 2.

Further, the through holes 1b to 1f are arranged in a row on the row A having the same coordinates on the Y axis, and the through holes 1g to 1j are arranged.
Are also arranged in one row on the B row having the same coordinates on the Y axis, and at this time, no light leakage occurs from the through holes 1g to 1j by the roller mask 3 provided on the lower surface of the printed board 1.

TV camera 7 hole center position, for example through holes 1b~1f outputs an image signal captured in the hole position address unit 8 images _{14 (x b, y b)} , (x c, y c), ··· (X _f , y _f ) is detected.

Next, the XY stage is moved by a drive mechanism (not shown), and the printed board 1 is moved in the direction of arrow 15 (shown in FIGS. 1 and 3). During this movement, the image of the area 2a is constantly confirmed by the TV camera 7, and this image signal is detected by the leak address section 12
Is output to. Through holes 1b to 1f arranged in row A
FIG. 3 (b) shows an image 16 when is moved by a distance p. This moving distance p is a distance that matches the length of the Y-axis of the rows A and B, and is equal to the data previously input to the hole pitch address section 10. Therefore, the image of the area 2a is input to the light leakage address unit 12, and at this time, for example, when there is light leakage in the through hole 1c, the address of this light leakage is output to the comparison unit 11. The leaked light from the through hole 1c is the light leaked even though the light from the light source is blocked by the roller mask 3, and indicates that the through hole 1c has a defect such as a cut or a pinhole.

On the other hand, an address signal obtained by adding the data of the pitch p between the through holes to the address signal of the through hole 1c read in the image 14 is input to the comparing unit 11.
At 11, both address signals match and a defect in the through hole 1c is detected. At this time, the address (coordinate position) of the defective through hole 1c can be displayed from the light leakage address section 12 to the outside.

In addition, there is light leakage from a portion of the printed board 1 where no pattern wiring is provided while the through holes 1b to 1f in the row A are moving. The image signal including this light leakage is also the light leakage address section 12
The address signal of this portion is also input to the comparison unit 11 from the light leakage address unit 12, but since the address does not have a through hole, the address signal input from the address addition unit 9 does not match and the position where the through hole exists. The defect detection signal is not output for light leaks other than.

Next, the XY stage is further driven to move the printed board 1 by one pitch in the direction of the arrow 15 and the same detection operation is repeated to detect defects in the through holes in sequence, and all through holes of the printed board 1 are detected. A defect inspection can be performed on the.

As described above, according to this embodiment, the roller mask 3 is provided on the lower surface of the printed board 1, and the filter 2 divided into the light transmission area 2a and the attenuation transmission areas 2b and 2c is provided on the upper surface of the printed board. The light transmitted through one through hole can be picked up by one TV camera 7. The TV camera 7 is a two-dimensional light receiving element, and it is necessary to provide two light receiving elements like the conventional through hole inspection device. There is no.

The present invention is not limited to the above embodiment, and for example, as shown in FIG. 4, a filter 17 may be provided below the TV camera 7 and only the light leak from the area 2a may be detected as it is. .

The light receiving element used in the present invention is not limited to the TV camera 7,
Any other dimensional light receiving element can be used.
Further, when the through hole provided on the printed board 1 is provided at an arbitrary position, means for detecting the hole position or the like of the through hole in advance and inputting the detection data to the hole position address section 8 or the like is provided. You may.

〔The invention's effect〕

As described in detail above, according to the present invention, when a defect such as a cut of metal plating or a pinhole of a through hole provided in a printed board is inspected, it can be performed by one light receiving element. The inspection device can be simplified.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a through-hole inspection device according to the present invention, FIG. 2 is a circuit block diagram of the through-hole inspection device, FIGS. 3 (a) and 3 (b) are configuration diagrams of TV images, and FIG. It is a block diagram which shows a part of schematic perspective view of other Example of this invention. 1 ... Printed board, 2, 17 ... Filter, 2a-2c ... Area, 3
...... Roller mask, 7 …… TV camera, 8 …… Hole position address part, 9 …… Address addition part, 10 …… Hole pitch address part, 11
…… Comparison section, 12 …… Leakage address section, 14,16 …… Image.

Claims (2)

(57) [Claims] 1. A through-hole inspection apparatus for detecting a light leakage pattern of a through-hole provided on a printed board to detect a defect in the through-hole, wherein light incident on the printed board is located on one surface of the printed board. A masking means for blocking light, a filter means located on the other surface of the printed board for attenuating a part of transmitted light from the printed board, an image pickup means for picking up the light passing through the filter means, An image forming unit which is located between the image pickup unit and the filter unit and forms an image of the light passing through the filter unit on the image pickup unit;
A through hole inspection apparatus, comprising: a control unit that performs defect detection control of the through hole based on a signal captured by the image capturing unit. 2. The through-hole inspection device according to claim 1, further comprising a detection unit that detects the position of the through-hole and the center position of the light leakage pattern.