JP7640999B2 - Circuit board visual inspection equipment - Google Patents

Description

The present invention relates to a board visual inspection device used in extremely small and delicate electronic devices.

For example, Patent Document 1 (JP Patent Publication No. 2001-41905) proposes the following configuration for the purpose of supporting the surface of a glass sheet without contact and attenuating the vibration of the glass sheet to allow high-speed movement.

That is, the patent document 1 discloses a configuration that includes an inclined air table arranged on a plane parallel to a first axis that is inclined with respect to the vertical, a means for moving the sheet material along the first axis and parallel to the air table and physically supporting the sheet material solely along its lower edge, an air supply means for supporting the sheet material parallel to the air table and at a desired distance from the air table so as to avoid physical contact with the surface portion of the sheet material, a scanning means, and a means for moving a manipulation means along a second axis that crosses at least one surface of the sheet material.

For example, Patent Document 2 (JP Patent Publication No. 2003-270155) shows a configuration in which a glass plate is supported opposite a holder made of a glass member having an opening formed therein for holding a glass substrate, and the glass substrate is held by suction on the highly rigid holder, in order to move the substrate in an aligned manner while suppressing bending and vibration without blocking irradiation from the rear surface of the substrate.

In the following, the glass sheet in Patent Document 1 and the glass substrate in Patent Document 2 will be referred to as "substrate" in the following explanation. Patent Document 1 describes a configuration in which the substrate is tilted during visual inspection and placed over an air gap to suppress vibration and to keep the substrate stationary in a non-contact state to keep it stable. However, this configuration has the problem that the substrate must be stopped once, which means that it takes a long time to perform visual inspection of a large number of substrates.

In addition, in Patent Document 2, an opening is formed in the center of the holder, which is installed on the step of the frame to maintain airtightness, to blow up the substrate and move it in an aligned manner, and a large number of air holes 10 are formed on the outer periphery of this opening to accommodate suction pads that suction and hold the peripheral edge of the substrate. However, Patent Document 2 also has a configuration in which the substrate is temporarily stopped during inspection in order to adjust the position, which causes the problem that it takes a long time to perform visual inspection of a large number of substrates.

The circuit boards referred to in this application refer to electronic components, but in recent years electronic components have become increasingly smaller, and large quantities are handled for shipment. Furthermore, it is necessary to inspect both sides, not just one side. Therefore, if the circuit boards are stopped (intermittent movement) or the circuit boards are turned over after inspecting the front side and then inspected on the back side, it would take a very long time to complete the inspection of the entire circuit board.

JP 2001-41905 A JP 2003-270155 A

The problem to be solved was that the transport of the board had to be stopped temporarily during inspection, making it impossible to efficiently inspect the appearance of both the front and back surfaces.

In order to solve the above problems, the present invention provides a chamber that forms a transport path for a substrate and is hollow inside, a porous plate having countless air jets on the upper surface of the chamber or countless air jets formed to cover the open surface of the chamber with the open upper surface, an air pump that sends air ejected from the air jets through the chamber, the chamber being divided into at least two in the transport direction with a gap that is less than 1/2 the transport direction dimension of the substrate, a transport surface side camera that images the substrate passing through this gap, an open surface side camera that is positioned in front of or behind the gap in the transport direction, and a pusher that pushes the substrate located in front of the gap on the transport path in the gap direction , and further the chamber is tilted so that the initial push-out position side of the pusher located in front of the gap in the substrate transport direction is downward .

In the present invention, a chamber forms a transport path, and air is ejected from the chamber toward the upper surface, causing the substrate to be in a levitated state, and the substrate is pushed out of the levitated state by a pusher, causing the substrate to move at high speed along the transport path. In addition, in the present invention, a backside camera captures the transport surface side of the substrate that moves while levitating without stopping at a location between chambers spaced apart by less than half the dimension of the substrate in the transport direction, and the open surface side of the substrate before or after the transport path at that distance. Thus, the present invention makes it possible to efficiently perform visual inspection of both sides of extremely small and large quantities of substrates.

1A and 1B show a schematic configuration of a substrate visual inspection device of the present invention, in which FIG. 1A is a schematic view seen from above, and FIG. 1B is a schematic view seen from direction A in FIG. 2 is a diagram showing a schematic configuration of a substrate visual inspection apparatus according to the present invention, as viewed from the direction B in FIG. In order to explain the inclination of the substrate transport path in the substrate visual inspection apparatus of the present invention, (a) shows only the periphery of the chamber as viewed from direction A in Figure 1(a), and (b) shows only the periphery of the chamber as viewed from direction B in Figure 1(b).

The present invention solves the problem that the transport of the substrate is temporarily stopped during inspection, making it impossible to efficiently inspect the appearance of both the front and back sides by providing a chamber that forms a transport path for the substrate and is hollow inside, a porous plate in which countless air jets are provided on the upper surface of the chamber or countless air jets are provided to cover the open surface of the chamber with the open upper surface, an air pump that sends air ejected from the air jets through the chamber, the chamber being divided into at least two in the transport direction with a gap that is less than 1/2 the transport direction dimension of the substrate, a transport surface side camera that images the substrate passing through this gap, an open surface side camera that is positioned in front of or behind the gap in the transport direction, and a pusher that pushes the substrate located in front of the gap on the transport path in the gap direction, and further by tilting the chamber so that the initial push-out position side of the pusher located in front of the gap in the substrate transport direction is downward .

This invention is primarily used when performing visual inspections on both sides of circuit boards for electronic devices. The circuit boards and electronic components themselves of modern electronic devices have become extremely small, and manufacturing sites have struggled to reduce the time required to inspect both sides of one circuit board per unit of time.

In addition, electronic device circuit boards, which have electronic devices and wiring mounted on them, are moved at high speeds, meaning that even normal circuit boards can be damaged if rubbed violently against the transport surface of the transport path. Therefore, the present invention makes it possible to move the board at high speeds along the transport path by levitating the board so that it is not in contact with the transport surface of the transport path, and by taking advantage of this low frictional resistance state and pushing it out with a pusher.

The gap between the chambers is a portion where no air is ejected from the chamber, but by making the gap less than half the dimension of the substrate in the transport direction, problems such as the leading edge of the substrate in the transport direction falling into the gap or getting caught and stopped do not occur. Therefore, the substrate is transported while being stably levitated.

In addition, a transport surface camera is provided on the opposite side of the air ejection direction in the gap between the chambers, and can capture an image of the transport surface side of the substrate passing through the gap. The open surface side of the substrate can be provided at the front or rear of the gap in the transport direction.

The spacing between the chambers may be changed within the above range of conditions depending on the dimensions of the substrate in the transport direction, but it is desirable to make the spacing as wide as possible, at the upper limit of the above range of conditions, i.e., half the dimensions of the substrate in the transport direction. The chamber may have numerous air outlets pre-formed on its upper surface, but a configuration in which a porous plate with numerous air outlets formed therein is placed on the upper surface has the advantage that cleaning when clogging occurs and changing the diameter and number of the air outlets can be easily performed by changing the porous plate.

In addition, in the above configuration, the present invention may be configured such that a guide extending in the substrate transport direction is provided on the edge of the chamber in a direction perpendicular to the substrate transport direction, and the guide side is tilted downward.

In the above configuration, it is assumed that the substrates are aligned in advance and transported to the process of the substrate visual inspection device of the present invention, but in some cases they may be transported to the process without being particularly aligned. Even if the substrates are aligned, they may lose their alignment due to floating. Therefore, if a guide is provided in the chamber and the chamber is tilted so that the guide side is downward, the substrate will move toward the guide due to gravity and will come into contact with the guide, thereby becoming aligned.

Furthermore, in the above-mentioned embodiment, the chamber may be tilted so that the initial push-out position of the pusher located before the gap in the substrate transport direction is downward.

In the above configuration, it is assumed that the pusher first pushes out the substrate at the beginning of the transport path formed in the chamber, causing the substrate to move while levitating, but in some cases the substrates may be transported to the process without being particularly aligned. Even if the substrates are aligned, in some cases the alignment may be disrupted by levitation.

Therefore, by tilting the chamber so that the pusher's initial push-out position is downward, the substrate can be brought into contact with the pusher and transported in a stable, aligned state. However, with this configuration, while the substrate transport speed depends on the speed of the pusher, there is an advantage in that the number of visual inspection processes per unit time can be easily controlled because the speed of the pusher is constant.

A specific embodiment of the present invention will be described below with reference to Figures 1 to 3. The substrate visual inspection device 1 of the present invention (hereinafter referred to as inspection device 1) has the following configuration in order to efficiently perform visual inspection of both the front and back surfaces of extremely small substrates W. Note that in this embodiment, the substrate W will be described as one used in electronic devices.

2 denotes a chamber that is hollow inside. In this example, two chambers 2 are provided in the transport direction with a gap S therebetween. In this example, the gap S is, for example, 1/2 the transport direction dimension of the substrate W. The two chambers 2, 2 provided with the gap S therebetween form a transport path for the substrate W. In this example, the chamber 2 has an open top surface, for example, and a porous plate 2A with countless air ejection holes h formed therein is provided to cover this open surface.

In this example, guides 2B are provided at the edges of the chambers 2, 2 in a direction perpendicular to the transport direction of the substrate W, spanning the space S in the transport direction. The chambers 2, 2 are inclined so that the guide 2B side faces downward. The inclination of the chambers 2, 2 is approximately 2° to 8°. If the inclination is less than 2°, the substrate W may not abut on the guide 2B, and if the inclination is more than 8°, the substrate W may jump over the guide 2B.
In the drawings, the angle is exaggerated.

Furthermore, in this example, the chambers 2, 2 are inclined so that the initial push position of the pusher 5 (described later) is downward before the gap S in the transport direction of the substrate W, i.e., on the upstream side in terms of the transport direction. The inclination of the chambers 2, 2 is approximately 5° to 15°. If the inclination is less than 5°, the substrate W may move with too much force during the initial push of the pusher 5 and may not come into contact with the pusher 5, whereas if the inclination is greater than 15°, the substrate W may be turned over and it may be difficult to adjust the height with the transport system of the next process (downstream process).

3 is an air pump that is connected to each of the chambers 2, 2 via a valve and supplies air to the chambers. In this example, the air pumps 3, 3 are provided corresponding to each of the chambers 2, 2 and adjusted to produce the same amount of air at the same pressure, but this is not limited to this, and pipes may be branched out from a single air pump 3 and connected to each of the chambers 2, 2.

4 is a camera that images the substrate W. In this example, there are provided a transport surface side camera 4A that images the substrate W passing through the space S, and an open surface side camera 4B that is arranged, for example, on the front side of the transport direction of this space S. The transport surface side camera 4A and the open surface side camera 4B are arranged so that their optical axes are perpendicular to the transport surface, and are arranged so that the entire width of the transport path is included in the viewing angle. In other words, in this example, since the chambers 2, 2 are arranged so that the guide side, the push-out initial position side of the pusher 5, is tilted downward as described above, the transport surface side camera 4A and the open surface side camera 4B are also arranged so that they are tilted relative to the horizontal.

5 is a pusher that pushes out the substrate W located in front of the gap S of the transport path in the direction of the gap S. This pusher 5 is composed of a push plate 5A that is provided in contact with the transport path and abuts against the substrate W, a movable part 5B that is connected to this push plate 5A outside the transport path beyond the guide 2B, a screw 5C that moves this movable part 5B in this example, a gear 5D that is provided coaxially with this screw 5C, and a motor 5F that applies rotational power via a pinion gear 5E that meshes with this gear 5D.

The inspection device 1 configured as above operates as follows. Air supplied from the air pump 3 is ejected into the chamber 2 from the air ejection holes h of the porous plate 2A. In the initial position, the push plate 5A of the pusher 5 is located at the left end of the paper in the state shown in FIG. 1(a). When a substrate W is transported from an upstream process in a direction perpendicular to the transport direction, from below the paper in the state shown in FIG. 1(a), the substrate W immediately becomes levitated and comes into contact with the guide 2B and the push plate 5A due to the inclination of the chambers 2, 2.

When the motor 5F is operated, the screw 5C rotates via the pinion gear 5E and the gear 5D, which in turn moves the movable part 5B and the push plate 5A connected to the movable part 5B, and the substrate W in contact with the push plate 5A is transported along the transport path.

When the substrate W reaches the position of the open surface side camera 4B during transport, the open surface side camera 4B images the open surface (top surface) of the substrate W, and when the substrate W reaches the interval S, the transport surface side camera 4A images the transport surface (bottom surface) of the substrate W. The image data from the camera 4 is sent to a control unit (not shown), which uses image processing technology to determine whether there are any abnormalities in appearance.

When the substrate W passes through the gap S and reaches the end of the transport path, the substrate W is removed from the transport path by another mechanism in the downstream process. After the substrate W is no longer present in the transport path, the push plate 5A returns to its initial position by the high-speed reverse rotation of the motor 5F, and after the push plate 5A has returned to its initial position, the next substrate W is transported from the upstream process.

In this way, with the present invention, the substrate W does not need to be temporarily stopped for visual inspection as it travels from the start to the end of the transport path, and visual inspection of the top and bottom sides can be completed as the substrate travels from the start to the end, increasing the processing capacity per unit time and making it possible to efficiently visually inspect a large number of substrates W.

REFERENCE SIGNS LIST 1 (Board appearance) inspection device 2 Chamber 2A Porous plate 2B Guide 3 Air pump 4 Camera 4A Conveying surface side camera 4B Opening surface side camera 5 Pusher 5A Push plate h Air outlet hole S Spacing W Board

Claims (2)

A board visual inspection device for performing visual inspection of both the front and back sides of extremely small electronic boards, comprising a chamber which forms a transport path for the board and is hollow inside, a porous plate which has countless air outlets on the upper surface of the chamber or which has countless air outlets formed so as to cover the open surface of the chamber with the open upper surface, an air pump which sends air emitted from the air outlets through the chamber, the chamber which is divided into at least two in the transport direction with a gap which is less than half the transport direction dimension of the board, a transport surface side camera which images the board passing through this gap, an open surface side camera which is positioned in front of or behind this gap in the transport direction, and a pusher which pushes out boards located in front of the gap on the transport path in the gap direction, and further wherein the chamber is tilted so that the initial push-out position side of the pusher located in front of the gap in the board transport direction is downward . The substrate visual inspection device according to claim 1, wherein the chamber is provided with a guide extending in the substrate transport direction at an edge in a direction perpendicular to the substrate transport direction, and is inclined so that the guide side faces downward.

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