JPH085572A - Visual inspection method for electronic device - Google Patents

Abstract

PURPOSE:To obtain visual inspection method for electronic device by which a solder bridge between the electrodes of an electronic device mounted on a board can be inspected optically and automatically. CONSTITUTION:A two electrode rectangular electronic device 73 is observed by means of a camera and scanning lines 79, 79a, 79b are set between the electrodes in order to inspect a solder 78 present on the scanning line 79, 79a or 79b. If a solder 78 is found, a decision is made that a solder bridge is present thus deciding that the soldered state is not acceptable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting the appearance of electronic parts for inspecting the presence or absence of solder bridges.

[0002]

2. Description of the Related Art After mounting an electronic component on a substrate, a visual inspection of the electronic component is performed. A typical inspection item of the appearance inspection is an inspection for the presence or absence of a solder bridge that short-circuits the electrodes of the electronic component.

Generally, the types and number of electronic components mounted on a board are quite large, and therefore it is desired to automatically inspect the presence or absence of a solder bridge by using an optical device such as a camera. Since the appearance inspection technology has not been established, it is the actual situation that the inspection of the presence or absence of the solder bridge is performed only by the operator's visual inspection.

[0004]

However, there is a problem in that the visual inspection by the operator does not improve the work efficiency.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a visual inspection method for electronic parts which can inspect the presence or absence of solder bridges using a camera.

[0006]

To this end, according to the present invention, an electronic component mounted on a substrate is observed from above by a camera to set a scanning line between electrodes of the electronic component, and a scanning line is set on the scanning line. The presence or absence of solder is detected, and if there is solder, it is determined that a solder bridge exists.

[0007]

According to the above construction, the presence or absence of the solder bridge can be automatically inspected easily and quickly by optically scanning between the electrodes with the camera.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a perspective view of an electronic component appearance inspection apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view of the recognition unit. 1 is a main body frame, 2 is a base plate, 3 is a pre-conveyor which carries in the substrate 4 in the direction of arrow H, 5 is a rear conveyor which carries out the substrate 4 in the direction of arrow M, 6 is a substrate holder for positioning the substrate 4, and 7 is defective A defective substrate stocker provided with a magazine 8 for accommodating the substrates 4a, and a recognition unit 9 provided above the substrate holder 6.

The substrate holder 6 has two guide rails 1
0, a movable base 12 that moves in the direction of arrow A by the motor 11 and the ball screw 11a. Further, two guides 13 are provided on the movable base 12, and the movable conveyor 14 is driven by a drive motor 15. Further, the movable base 12 is provided with a fixed side conveyor 14a, and the movable side conveyor 14 is configured to move with the fixed side conveyor 14a as a reference.
Moreover, a handle 16 and a screw 17 are provided to adjust the distance between the movable side conveyor 14 and the fixed side conveyor 14a according to the width of the substrate 4, and the movable side conveyor 14 is locked by a lock handle 18. .

The fixed side conveyor 14a has a cylinder 1
A substrate stopper 20 which operates in the direction of arrow B by 9;
A substrate detection sensor 21 that detects the presence or absence of the substrate 4 is provided. The movable conveyor 14 has a clamper 23 for clamping the substrate 4 in the direction of arrow C with a cylinder 22.
Is provided. Therefore, the substrate 4 is
When the driving motor 11 is driven, the movable base 12 is moved along the guide rail 10 by the arrow A.
In the same direction, the substrate 4 also moves in the same direction. That is, the motor 11, the movable base 12, and the like are moving means for moving the substrate 4 in the horizontal direction with respect to the recognition unit 9.

The rear conveyor 5 is provided with a fixed side conveyor 25 supported by a bracket 24, and a movable side conveyor 28 supported by a guide 26 and a bracket 27 and slidably provided. Movable side conveyor 28
Can be moved in the direction of arrow D by a handle 29, a screw 30, and a lock handle 31. Further, the movable conveyor 28 is driven by a motor 32, a pulley 33 and a shaft 34.

The defective substrate stocker 7 is provided with two bearings 35 and two shafts 36 fixed to the base plate 2. Further, the drive device 37 and the rack 37a allow the lifter base 38 provided on the upper part of the drive device 37 to move in a pitch direction in the arrow E direction.

The recognition unit 9 is provided with two posts 39 fixed on the base plate 2, and a block 40 is provided on the posts 39. In the block 40, two guides 41 are provided in the same direction as the substrate 4 conveyance direction, and another block 42 that slides along the guide 41 is provided. Block 42 is the motor 4
3 and the ball screw 44 move in the direction of arrow F. On the block 42, a light source 45, a fiber 45a, and a slit unit 45b that blocks light are provided.

In the block 42, the recognition unit 9 is indicated by an arrow G.
Drive device 47 provided with a motor 46 for horizontally rotating in one direction
And a bearing 49 that allows the main body frame 48 of the recognition unit 9 to rotate is provided below the drive device 47. By driving the motor 46 to horizontally rotate the recognition unit 9 in the direction of arrow G, it is possible to change the capturing direction of the image of the electronic component according to the direction of the electronic component mounted on the substrate 4.

The body frame 48 is provided with a camera 50 and an illumination lamp 51 for recognizing the position of the substrate 4.
The main body frame 48 has a camera 53 (hereinafter referred to as a top camera) arranged such that the optical axis is perpendicular to the upper surface of the substrate 4, and a ring-shaped illumination that irradiates the substrate 4 with light from above. A plurality of (four in this embodiment) cameras 55, 55a, 55 are provided with a lamp 54 and arranged so that the optical axis is oblique to the upper surface of the substrate 4.
b, 55c (hereinafter referred to as side cameras), and a plurality of illumination lamps 56, 56a, 56b, 56c connected to the fiber 45a and irradiating the substrate 4 with light obliquely from above.

As shown in the figure, the side cameras 55 and 55a are arranged symmetrically with respect to each other with the top camera 53 as the center, and the side cameras 55b and 55c similarly have the top camera 53 as the center. Opposite symmetrically. By arranging two pairs of the left and right side cameras 55, 55a and 55b, 55c in this way, as described later with reference to FIGS. 9 to 12, it is possible to accurately detect the floating or positional deviation of the electronic component. . Further, a marker 57 for marking a defective electronic component or a defective portion is provided above the substrate holder 6 according to the appearance inspection result of the mounted state or the soldered state of the electronic component 52 mounted on the substrate 4.

When the driving motor 43 is driven, the block 42 horizontally moves along the guide 41 in the arrow F direction. The recognition unit 9 and the marker 57 are assembled integrally with the block 42, and therefore move horizontally in the direction of arrow F together with the block 42. That is, the guide 41, the block 42, and the motor 43 are moving means for moving the recognition unit 9 and the marker 57 in the horizontal direction (F direction) with respect to the substrate 4. Here, the arrow A direction and the arrow F direction are directions orthogonal to each other, and therefore, the motor 4 drives the motor 11 and the motor 43, so that the board 4 causes the recognition unit 9 and the marker 57 to move.
It is possible to move horizontally relative to the directions A and F.

The operation of the electronic component appearance inspection apparatus configured as described above will be described. In FIG. 1, first, the substrate 4 is placed on the front conveyor 3. Then, the substrate 4 is transported by the front conveyor 3 in the direction of arrow H, and the stopper 20 positions the substrate in the substrate transport direction. After that, when the substrate detection sensor 21 detects the substrate 4, the clamper 23 moves in the C direction by the cylinder 22,
The substrate 4 is clamped and positioned. Then, the state of the positioned substrate 4 is recognized by the camera 50 and the illumination lamp 51, and the control device calculates the inclination and the positional deviation of the substrate 4. Then, the motor 11 and the motor 43 are driven based on the correction value calculated from the inclination and the positional deviation of the substrate 4 and the master pattern data stored on the substrate 4 in advance,
The board 4 is horizontally moved relative to the recognition section 9 in the A direction and the F direction, and a predetermined electronic component 52 mounted on the board 4 is positioned at a visual inspection position by the recognition section 9. The visual inspection described later is performed.

Next, the control device will be described. FIG. 3 is a functional block diagram of an electronic component appearance inspection apparatus according to an embodiment of the present invention. Reference numerals 53, 55, 55a, 55b, and 55c are television cameras that capture images of the electronic component 52 on the substrate 4. The TV camera 53 is a top camera, and the TV cameras 55, 55a, 55b, 55c are side cameras. 58 to 62 are TV cameras 55, 55a, 55
A camera control unit for converting the image level taken in from b, 55c into a standardized composite video signal, 63 is an image switching unit, and the image taken in from each television camera is selected by the camera switching selection signal. Only one can be selected.

Reference numeral 64 is a video circuit for generating an external synchronizing signal. With this external synchronization signal, each television camera can capture all completely synchronized images. 65
Is a video bus, and 66 is a status and control bus. 67 is a frame memory (TFM) composed of 512 × 512 × 8 bits, which is a place for storing the original image captured by each television camera. 68,69
Is a working memory (512 × 512 × 8 bits) for storing image information that has been subjected to image conversion after performing necessary processing, and one working memory (DMI) 68 stores image information classified by brightness, The other working memory (DMII) 69 stores the filtered video information. Reference numeral 70 denotes a CPU that controls operations related to inspection
Is a control unit. 71 is a memory composed of a read-only memory and a random access memory, and 72 is an I / O
It is a control unit.

Next, the operation of the control unit 70 will be described. FIG.
3 is a flowchart showing the operation of the control unit of the electronic component appearance inspection apparatus according to the embodiment of the present invention. In step 1, first, an image of the electronic component 52 mounted on the substrate 4 is captured from the top camera 53. In step 2, an inspection parameter is searched by data such as coordinates, brightness, direction, type of the electronic component 52 mounted on the board 4.
In step 3, the video in which only the required brightness is extracted is transferred from the frame memory 67 to the working memory 68. In step 4, the frame-enhanced or smoothed image or the like is transferred from the frame memory 67 to the working memory 69. In step 5, the electronic component 5 mounted on the substrate 4
The determination of the brightness of the second electrode portion and the determination of the position displacement dimension at a predetermined place are performed. In step 6, the camera is switched or not switched. If the cameras are not switched, the inspection ends. When the camera is switched, the top camera 53 is switched to the side cameras 55, 55a, 55b, 55c in step 7, and a video of the electronic component 52 is newly captured.

The appearance inspection apparatus for electronic parts is constructed as described above. Next, the appearance inspection method for electronic parts will be described. First, a method of inspecting a positional shift of electronic components and a missing item by the top camera 53 will be described. FIG. 5 is a plan view of a two-electrode prismatic electronic component observed by a top camera of an electronic component appearance inspection apparatus according to an embodiment of the present invention. The two-electrode prismatic electronic component 73 has electrodes on both sides. As shown in the figure, four areas 74, 74a, 74b, and 74c, which respectively include four corners, which are characteristic portions of a plane shape, are set based on master pattern data stored in advance, and each of the areas 74 to 74c is set. Image data from top camera 5
Take in 3. If the corner area image is included in all of the four areas 74 to 74c, the mounted state is determined to be good. Further, if at least any one of the four areas 74 to 74c does not include a corner image, it is determined that there is a positional deviation, and all four areas 74 to 74c have corner images. If there is not, it is judged as out of stock.

FIG. 6 is a plan view of the mini-transistor leg electronic component observed by the top camera of the electronic component appearance inspection apparatus according to the embodiment of the present invention. The mini-transistor foot electronic component 75 has three electrodes, and the quality of the mounting state of the electronic component 75 is the same as in the case of the two-electrode rectangular electronic component 73, and the master pattern data stored in advance is used. 3 including 3 feet (electrodes) based
Two areas 76 to 76b are set. And electronic parts 75 with mini transistor foot in all areas 76-76b
If the image of the foot (electrode) is included, the mounted state is determined to be good. Further, if any one of the three areas 76 to 76b does not include the foot (electrode) image, it is determined that there is a positional deviation, and the three areas 76 to 76b include all the foot images. If not, it is determined to be out of stock.

As described above, according to this method, the corners of the two-electrode rectangular electronic component 73 and the mini-transistor leg electronic component 7 are used.
Setting an area including a plurality of planar feature portions of electronic parts such as 5 feet (electrodes) and inspecting with the top camera 53 whether or not the image of the feature portion is included in the area. This makes it possible to easily and reliably determine the misalignment of electronic components and missing items.

Next, a method of inspecting the presence or absence of the solder bridge will be described. FIG. 7 is a plan view of an electronic component observed by a top camera of an electronic component appearance inspection apparatus according to an embodiment of the present invention, and FIG. 8 is a plan view of the same two-electrode rectangular electronic component. First, in FIG. 7, scanning lines 77, 77a, 77 are provided between the electrodes based on the master pattern data stored in advance.
b and 77c are set. And scan lines 77-77c
The presence or absence of the upper solder 78 is inspected, and if there is the solder 78, it is determined that a solder bridge exists, and the soldering state is determined to be defective.

In the case of the two-electrode prismatic electronic component 73 shown in FIG. 8, scanning lines 79, 79a, 7 are provided between the electrodes.
Set 9b. Then, the presence or absence of the solder 78 on the scanning lines 79 to 79b is confirmed, and if the solder 78 is present, it is determined that a solder bridge is present, and the soldering state is determined to be defective. As described above, according to this method, it is possible to easily inspect whether or not there is a solder bridge that causes a short circuit.

Next, a visual inspection method using a side camera will be described. 9 to 12 are explanatory views of the appearance inspection method by the side camera of the appearance inspection apparatus for electronic parts according to the embodiment of the present invention. FIG. 9 shows the floating of the electronic component 52 with respect to the substrate 4.
When there is no displacement, the two images 80 and 81 of the electronic component 52 captured by the two side cameras serve as reference images.

Now, as shown in FIG. 10, when there is no displacement of the electronic component 52 with respect to the substrate 4 but there is a float of Δh,
Image 82 of electronic component 52 captured by one side camera
Is displaced in the direction of arrow I, and the position of the image 83 captured by the other side camera is displaced in the direction of arrow J. Therefore, by comparing the positions of the images 82 and 83 with the positions of the reference images 80 and 81 to obtain the displacement, the electronic component 52
It is possible to easily determine that there is a float.

Further, as shown in FIG. 11, when the electronic component 52 does not float with respect to the substrate 4 but there is a positional deviation of Δx,
Image 84 of electronic component 52 captured by one side camera
Is displaced in the direction of arrow K, and the position of the image 85 of the electronic component 52 captured by the other side camera is displaced in the direction of arrow L. Therefore, it can be easily determined from this displacement that there is a displacement.

Next, as shown in FIG. 12, when there is both a floating Δh and a positional deviation Δx of the electronic component 52 with respect to the substrate 4, an image 86 of the electronic component 52 captured by the side camera,
87 is displaced as shown by the displacement of Δx and the floating of Δh. In this case, the shift amount of Δx is obtained from the image of the electronic component 52 captured from the top camera 53, and the floating amount of Δh is based on the shift amount of Δx obtained from the image of the electronic component 52 captured from the top camera 53. , It can be obtained from the image of the electronic component 52 captured from the side camera.

The appearance inspection of the electronic component is performed as described above. For the defective electronic component, the motor 11 and the motor 43 shown in FIG. By moving horizontally, defective electronic parts or defective parts are marked. And good board 4
Is conveyed in the direction of arrow M, but the defective substrate 4a is stored in the magazine 8 of the defective substrate stocker 7 by moving the substrate holder 6 in the direction of arrow A.

[0032]

As described above, according to the present invention, it is possible to automatically and promptly perform a visual inspection by a camera for a solder bridge between electrodes of an electronic component mounted on a board. it can.

[Brief description of drawings]

FIG. 1 is a perspective view of an appearance inspection apparatus for electronic parts according to an embodiment of the present invention.

FIG. 2 is a perspective view of a recognition unit of an appearance inspection apparatus for electronic parts according to an embodiment of the present invention.

FIG. 3 is a functional block diagram of an appearance inspection apparatus for electronic parts according to an embodiment of the present invention.

FIG. 4 is a flowchart showing the operation of the control unit of the electronic component appearance inspection apparatus according to the embodiment of the present invention.

FIG. 5 is a plan view of a two-electrode prismatic electronic component observed by a top camera of an electronic component appearance inspection apparatus according to an embodiment of the present invention.

FIG. 6 is a plan view of the mini-transistor foot electronic component observed by the top camera of the electronic component visual inspection apparatus according to the embodiment of the present invention.

FIG. 7 is a plan view of an electronic component observed by a top camera of an electronic component appearance inspection apparatus according to an embodiment of the present invention.

FIG. 8 is a plan view of a two-electrode prismatic electronic component observed by a top camera of an electronic component appearance inspection apparatus according to an embodiment of the present invention.

FIG. 9 is an explanatory diagram of an appearance inspection method using a side camera of an appearance inspection apparatus for electronic parts according to an embodiment of the present invention.

FIG. 10 is an explanatory diagram of an appearance inspection method using a side camera of an appearance inspection apparatus for electronic parts according to an embodiment of the present invention.

FIG. 11 is an explanatory diagram of an appearance inspection method using a side camera of an appearance inspection apparatus for electronic parts according to an embodiment of the present invention.

FIG. 12 is an explanatory diagram of an appearance inspection method using a side camera of an electronic component appearance inspection device according to an embodiment of the present invention.

[Explanation of symbols]

 4 board 6 board holder 9 recognition part 11 motor 12 movable base 13 guide 41 guide 42 block 43 motor 52 electronic part 53 top camera 54 lighting lamp 55 side camera 55a side camera 55b side camera 55c side camera 56 lighting lamp 56a lighting lamp 56b lighting Lamp 56c Illumination lamp 73 Bi-electrode square electronic component 74 Area 74a Area 74b Area 74c Area 75 Mini-transistor leg electronic component 76 Area 76a Area 76b Area 77 Scan line 77a Scan line 77b Scan line 77c Scan line 78 Solder 79 Scan line 79a Scan Line 79b Scan line

Claims (1)

[Claims] 1. An electronic component mounted on a substrate is observed from above by a camera, a scanning line is set between electrodes of the electronic component, the presence or absence of solder on the scanning line is detected, and solder is detected. If there is a solder bridge, it is judged that there is a solder bridge.