JPH0981717A - Inspecting method for solder bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inspecting method for a solder bridge which can suppress misdecisions by irradiating the periphery of plural leads of an electronic component with light from a light source along the length of the leads, fetching an image from a camera and setting an inspection window between the leads, and inspecting whether or not there is the solder bridge between the leads according to the image in the inspection window. SOLUTION: The visual field of the camera 14 is set to the periphery of a side L1 of the electronic component 1, only blocks A and C of the light source 15 are turned on, and blocks B and D are turned off. Namely, the leads present at the side L1 are irradiated with light from only the blocks A and C along the length of the leads. Then the image of the side L1 is obtained, the inspection window is positioned between the leads in the obtained image, and inspection is performed as to the side L1. Thus, the light emitted from the light source 15 is made parallel to the lengthwise direction of the leads to prevent a bright image irrelevant to the solder bridge from being generated, thereby suppressing misdecisions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder bridge inspection method for inspecting whether a solder bridge has occurred after soldering an electronic component having a plurality of leads to an electrode of a substrate.

[0002]

2. Description of the Related Art Some electronic components, such as QFP and SOP, have a plurality of leads, and each lead is soldered to a circuit pattern formed on a substrate.

Next, a conventional method for inspecting a solder bridge will be described with reference to FIGS. 6 and 7. FIG. 6 is a partially enlarged plan view of a board when a conventional solder bridge is inspected. In FIG. 6, 1 is a plurality of leads 2, 3
And electronic components 4 having a substrate, 5 and 6 are circuit patterns formed on the substrate 4, and leads 2 and 3 are soldered to the circuit patterns 5 and 6 by solders 7 and 8, respectively. 9 and 10 are fluxes applied to the substrate 4 before soldering.

In the conventional solder bridge inspection method, the vicinity of the circuit patterns 5 and 6 on the substrate 4 is observed with a camera from above. FIG. 7 is an exemplary diagram showing a conventional image.

Now, as shown in FIG. 7, in the conventional solder bridge inspection method, the inspection window 11 is positioned between the leads 2 and 3 in order to detect the presence or absence of the solder bridge. If there is a solder bridge, solder 7,
The image of the bridge connecting 8 is the inspection window 1
1 and, as a result, a bright image appears in the inspection window 11 as a judgment factor.
The presence or absence of the bridge was judged based on the brightness of the image inside.

[0006]

However, as described above, the fluxes 9 and 10 are applied to the substrate 4 before the solders 7 and 8 are soldered. Also,
In the conventional solder bridge inspection method, the circuit pattern 5,
Light was radiated to the vicinity of 6 from all directions of 360 °. Therefore, as shown in FIG. 6, the flux 9,
The peripheral portions of 10 become bright images 12 and 13, and the bright images 12 and 13 may be partially included in the inspection window 11. At this time, the inspection window 11
Since the images inside contain bright images 12 and 13, this is interpreted as a solder bridge, and it may be erroneously determined to be a bridge even though the bridge is not actually formed. was there.

Therefore, an object of the present invention is to provide a solder bridge inspection method capable of suppressing erroneous determination.

[0008]

A solder bridge inspection method according to the present invention irradiates light from a light source in the vicinity of a plurality of leads of an electronic component in a direction along the longitudinal direction of the leads, captures an image from a camera, and leads the leads. An inspection window is set in between, and the presence or absence of a solder bridge between the leads is inspected based on the image in the inspection window.

[0009]

With the above construction, light is emitted from the light source along the longitudinal direction of the lead. Therefore, when the flux has an edge portion along the longitudinal direction of the lead in the inspection window in the longitudinal direction of the lead, the edge portion does not shine brightly. Therefore, it is less likely that a bright image, which is not the solder bridge, will enter the inspection window, and as a result, misjudgment can be suppressed.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. It should be noted that the same components as those in FIGS. 6 and 7 showing the conventional configuration are denoted by the same reference numerals and the description thereof will be omitted.

FIG. 1 is a block diagram of a solder bridge inspection apparatus according to an embodiment of the present invention. In FIG. 1, 14 is a camera for observing the board 4, 15 is a light source for brightly illuminating the field of view of the camera 14, and the light source 15 is each side L1, L2, L3, L4 of the electronic component 1 mounted on the board 4. Is divided into blocks A, C, B, and D corresponding to.

16 is a table that holds the substrate 4 and moves the substrate 4 in the XY directions with respect to the camera 14, 17 is a CPU that controls the whole, 18 is a RAM in which the CPU 17 stores temporary information, and 19 is a camera 14. An image processing unit that performs image processing such as determination of presence / absence of a solder bridge on the image obtained from the above, 20 is an image memory that stores the image obtained by the camera 14, and the image in the image memory 20 is The image is displayed on the worker by being drawn on the display device 21. Reference numeral 22 indicates the image acquired by the camera 14 in the CPU 1
Interface for converting information that can be decrypted by 7
Controls the light source 15 so that each block A,
An illumination control unit for independently turning on / off B, C and D, 24
Is a table control unit for controlling the moving state of the table 16.

FIG. 3 is a flow chart of a solder bridge inspection method according to an embodiment of the present invention. Next, the solder bridge inspection method of this embodiment will be described with reference to FIG.

First, in step 1, the field of view of the camera 14 is set near the side L1 of the electronic component 1, and the light source 15
Only blocks A and C are turned on and blocks B and D are turned off (step 2). That is, light is emitted only from the blocks A and C along the longitudinal direction of the lead existing on the side L1. Then, the image of the side L1 is acquired, and the inspection window is positioned between the leads in the obtained image as described above, and the inspection of the side L1 is performed (step 3).

FIG. 4 is a partially enlarged plan view of the inspection in one embodiment of the present invention. As shown in FIG. 4, leads 25 to 28 are extended to the side L1 and circuit patterns 29 to 32 corresponding to the leads 25 to 28, respectively.
Are formed on the substrate 4. And leads 25-2
8 is fixed to the circuit patterns 29 to 32 by solders 33 to 36. Further, in this example, the bridge 37 is formed between the solders 34 and 35.

An image obtained by the processing of steps 1 to 3 is shown in FIG. In FIG. 5, the inspection window 38, the lead 26,
An inspection window 39 is set between 27 and an inspection window 40 is set between the leads 27 and 28. As indicated by an arrow N, light is emitted only along the longitudinal direction of the leads 25 to 28 existing on the side L1. The surface of the solder 33 is an inclined surface, and the surface is covered with the flux 47 in a film shape. When light is emitted along the longitudinal direction of the lead 25, the light (arrow P1) emitted to the solder 33 on the tip end side of the lead 25 is reflected upward by the liquid surface of the flux 47 (upper direction perpendicular to the paper surface).

The light (arrow Q1) applied to the solder 33 on the side of the lead 25 is reflected obliquely upward by the liquid surface of the flux 47. Therefore, as shown in FIG. 5, in the image captured by the camera 14 located directly above the side L1, only the portions of the edges of the solder 33 to the solder 36 and the bridge 37 that are substantially perpendicular to the arrow N are bright. Images 41 to 46 appear, and other images are dark.

Therefore, in the inspection windows 38 and 40, the entire area is a dark image, and in the inspection of step 3, it is determined that no bridge exists at these locations. On the other hand, in the inspection window 39, a bright image 45,
It is determined that the bridge 37 exists because 46 exists.

As described above, by making the direction of the light emitted from the light source 15 parallel to the longitudinal direction of the lead, a bright image unrelated to the solder bridge is not generated and erroneous determination can be suppressed. it can.

In step 4, the field of view of the camera 14 is set to the side L.
2 is set, and the light source 15 is left as described above to inspect the side L2 (step 5). And the camera 14
Is set to L3, the blocks A and C are turned off, the blocks B and D are turned on, and the side L3 is inspected (steps 7 and 8). Further, while keeping the lighting state of the light source 15 at Step 7, the visual field is set to the side L4, and the side L4 is inspected (Steps 9 and 10).

[0021]

According to the solder bridge inspection method of the present invention, light is emitted from the light source along the longitudinal direction of the lead, so that an undesired bright image is prevented from appearing in the inspection window to make an erroneous determination. Can be suppressed.

[Brief description of drawings]

FIG. 1 is a block diagram of a solder bridge inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of a light source according to an embodiment of the present invention.

FIG. 3 is a flowchart of a solder bridge inspection method according to an embodiment of the present invention.

FIG. 4 is a partially enlarged plan view of an inspection in one embodiment of the present invention.

FIG. 5 is an exemplary view showing an image in one embodiment of the present invention.

FIG. 6 is a partially enlarged plan view of a board when a conventional solder bridge is inspected.

FIG. 7 is an exemplary view showing a conventional image.

[Explanation of symbols]

 1 electronic component 14 camera 15 light source

Claims (2)

[Claims] 1. A light source irradiates light in the vicinity of a plurality of leads of an electronic component, an image is captured from a camera, an inspection window is set between the leads, and an interval between the leads is determined based on an image in the inspection window. A solder bridge inspection method for inspecting the presence or absence of a solder bridge, wherein light is emitted from the light source in a direction along the longitudinal direction of the lead. 2. The method for inspecting a solder bridge according to claim 1, wherein the light source is composed of a plurality of blocks divided according to the direction of the leads, and the blocks are selectively turned on.