JPS5940783Y2 - Device for detecting soldering quality of chip parts - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for detecting the quality of soldering of so-called chip components without lead wires.

In recent years, resistors, capacitors, diodes, etc. used in the electronic circuits of so-called home appliances such as television receivers and radio receivers no longer have lead wires, and their sizes have become about a fraction of the size of conventional products. So-called chip parts have come into use.

There are various sizes of such chip components, but the typical ones used in home appliances are approximately 3.2 mm in length.
It is a rectangle with a width of about 1.6mm and a thickness of about 0.7mm, and has electrodes at both ends.The electrodes are connected to the copper foil part of the printed circuit board by soldering to form an electronic circuit. There is.

Conventionally, when connecting these types of chip components, skilled workers visually discovered defective soldering points, or used a sharp detection pin on a continuity tester to connect the copper foil pattern on the printed circuit board. It used to be used to detect defective soldering by applying it between the electrodes of chip components, but the former method is inefficient because it often misses things and causes a lot of worker fatigue.

In the latter method, there are many contact failures of the detection pins, and the reliability of detection is low.

This invention was devised to eliminate such conventional problems, and will be explained in detail below with reference to the drawings.

Fig. 1 is a side view of the device of this invention used to detect the quality of soldering of chip components. 1 is a printed circuit board, 2 and 2' are copper foil patterns on the printed circuit board, and 3 is a copper foil on the other side. a chip component connected between patterns 2 and 2';4;
4' is an electrode portion of the chip component, and 5, 5', and 6 are solder (soldering portions) for connecting the electrode 4.4' of this chip component and the Ml patterns 2, 2'.

7 is a light source that applies a beam of light obliquely to the soldered portion 5.5't or 6 of the chip component 3 soldered to the printed circuit board 1;
is an imaging device such as a television camera that takes an enlarged image of a several-dimensional area near the electrode end of a chip component in order to detect the reflected light from the soldered portion 5, 5't or 6, and these light sources 7 and The imaging device 8 is moved relative to and above the soldered portion by a moving device (not shown).

Note that the above-mentioned relative movement means either fixing the printed circuit board 1 side and moving the light source and the imaging device 8, or conversely, fixing the light source 7 and the imaging device 8 side and moving the printed circuit board. The first step is to move the first side.

The light source 7 is arranged so that the light source hits the soldered part diagonally from the chip component side, and the imaging device 8 is specifically a television camera with a magnifying glass or an image sensor. After converting changes in light into changes in electrical signals, an appropriate discrimination circuit (not shown) is provided, and the output of the discrimination circuit drives a display device, a printing device, or an alarm device (not shown).

Next, to explain the effect, in FIG. 1A, the electrode 4 of the chip component 3 and the copper foil pattern 2 are not connected to the soldered part on the left side of the chip component 3 for some reason. , a gap G exists between the solder 5 and the solder 5'.

This gap G is usually several tens of microns to several hundred microns, and is easily overlooked by the naked eye.

The soldered portion on the right side is in good condition, and the solder 6 is attached obliquely from the electrode 4' to the copper foil pattern 2'.

Therefore, as shown in FIG. 1A, the light source 7 and the imaging device 8 are arranged as shown in the figure, and as shown by the arrow A, the soldered portion 6 on the right side of the chip component 3 soldered to the printed circuit board 1 is Looking at the range of several degrees, the imaging device 8 detects that the change in the brightness of the reflected light at the soldered portion 6 is not sudden, as shown in FIG. 2, and this indicates that the soldering is good. I understand that.

On the other hand, the left side of Fig. 1B shows a case where the soldering is defective. When viewed with a magnifying glass, the gap G with no solder is concave, so when the light beam from the light source I is applied from diagonally above the right side, As shown in FIG. 3, the reflected light suddenly becomes dark in the gap G, that is, the imaging device 8 detects that the brightness of the reflected light changes suddenly, and this indicates that the soldering is defective. I understand that there is something.

For example, when looking at the soldered part of a component with two electrodes, such as a resistor chip or a capacitor chip, when looking at the soldering on the left side, shine the light diagonally from the upper right, and when looking at the soldering on the right side, shine the light beam diagonally. It is easier to detect if you hit it from the upper left.

In addition, the light source and imaging device are fixed, the printed circuit board to which the chip components are soldered is placed on a freely movable table, and the table is automatically moved so that each soldered part is below the imaging device. By making it possible to move the target, it is possible to automatically detect soldering defects.

Further, the field of view of the imaging device has a radius of 0.
A circular range of about 6 mm is appropriate.

As described above, this idea consists of a light source that applies a beam of light obliquely to the soldered part of a chip component soldered to a printed circuit board, an imaging device that detects the reflected light from the soldered part, and a combination of these light sources and the imaging device. It is characterized by a moving device that sequentially moves the device relative to the soldering portion, and configured to detect whether the soldering is good or bad based on the difference in detection of reflected light depending on the quality of the soldering in the soldering portion. Since we have provided a device for detecting the soldering quality of chip components, conventionally, workers had to look for soldering defects with their naked eyes, or they could use the sharp detection pin of a continuity tester to detect soldering defects by touching the copper foil of a printed circuit board. Previously, we used to search for defective soldering by applying the sensor between the pattern and the electrode of the chip component, but this device for detecting the defective soldering of chip components automatically and accurately detects the location of the defective soldering. can be detected, and work efficiency can also be improved.

[Brief explanation of drawings]

Figures 1A and B are schematic diagrams of how the soldering quality detection device of this invention detects soldering defects. Figures 2 and 3 are diagrams showing changes in the brightness of reflected light from the soldered area by an imaging device. This shows that. 1... Printed circuit board, 2, 2'... Copper foil pattern,
3... Chip component, 4,4'... Electrode, 5.5'
, 6...Soldering part, 1...Light source, 8...Imaging device, G...Gap.

Claims (1)

[Scope of utility model registration request] A light source that applies a beam of light diagonally to the soldered part of a chip component soldered to a printed circuit board, an imaging device that detects the reflected light from the soldered part, and a light source and imaging device that sequentially illuminate the soldered part. Detecting the quality of soldering of a chip component, comprising a moving device for moving the soldered part, and configured to detect the quality of soldering based on the difference in detection of reflected light depending on the quality of soldering of the soldered part. Device.