JP2765568B2 - Infrared lead floating inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared lead floating inspection apparatus and, more particularly, to an infrared lead floating inspection apparatus for detecting a lead floating failure of an electronic component mounted on a printed circuit board.

[0002]

2. Description of the Related Art Conventionally, as an inspection device for detecting lead floating of an electronic component mounted on a printed circuit board, a method of detecting the lead floating by a visual inspection device using a camera and a difference in temperature distribution of an IC terminal portion are known. There is a method of detecting lead floating, a method of detecting lead floating based on a difference in sound, and the like.

In the case of a method of detecting lead floating by a visual inspection device using a camera, an operator detects the lead floating from the image displayed on a monitor by photographing a terminal portion of an electronic component with a camera. .

In the method of detecting lead floating from a difference in temperature distribution at an IC terminal, a joint including a heat conducting member is irradiated with thermal energy, and infrared rays emitted from the joint are received by an infrared camera. A temperature distribution image reflecting the temperature distribution of the junction is generated, and the quality of the junction is determined by comparing the temperature distribution image with a standard temperature distribution pattern. This method is disclosed in JP-A-63-3052.
No. 38 discloses this in detail.

[0005] In the case of a method of detecting lead floating based on a difference in sound, vibration transmitted to a soldering portion of a printed circuit board to be inspected by a transmitting probe is detected by a receiving transducer at a required position. Then, the amplitude of the output waveform of the receiving oscillator is monitored. This method is disclosed in
The details are described in Japanese Patent No. 221658.

In the case of another method for detecting lead floating based on a difference in sound, mechanical vibration is applied to an electronic component soldered and mounted on a substrate in the form of a sound wave, and the vibration generates an electronic component. The resonance characteristic is measured as a reverberation spectrum, and it is determined whether or not the reverberation spectrum contains a frequency component caused by a lead / open defect. This method is described in detail in JP-A-2-67956.

On the other hand, vibrations are applied to the soldered portions of the electrodes of the electronic component by a vibrating device to bring the measuring probe into contact with the electronic component and the pattern of the board on which the electronic component is mounted,
There is also a method of measuring the electrical state between the electronic component and the pattern to determine the quality of the soldered state. This method is described in detail in JP-A-6-313785.

A laser beam is radiated to the portion to be inspected while being intermittent near the natural vibration frequency of the electrode of the electronic component to be inspected, and a signal such as heat or sound generated by a change in the solder joint portion due to the laser beam is generated. Convert the signal into a signal, and measure the amplitude level of the output frequency of the transmission signal generation unit that interrupts the laser light from the electric signal to determine whether the soldering unit is good or not.
There is also a method of determining a defect. This method is described in detail in JP-A-6-66530.

Further, the object to be measured is irradiated with a one-dimensional or two-dimensional laser beam, and amplitude vibration caused by thermal expansion and contraction generated at the electrode of the object by the irradiation of the laser beam,
That is, there is a method of measuring the thermal vibration phenomenon of the solder joint to determine whether the soldered part is good or not. For this method,
This is described in detail in JP-A-7-198351.

[0010]

In the above-described conventional method for inspecting lead floating, in the case of detecting the lead floating by an appearance inspection device using a camera, an operator reads the image captured by the camera with the naked eye. Since the floating must be detected, the detection of the lead floating may be missed.

In the method of detecting lead floating from the difference in the temperature distribution of the IC terminal portion, if only the temperature gradient is used, the heating time depends on the pattern of the substrate and the density of the components. It is difficult to detect a subtle lead floating.

Further, in the case of the method of detecting lead floating based on the difference in sound, the sound is easily affected by external noise and the like, and it is difficult to suppress the noise of the device itself. It has a big effect.

On the other hand, in the case of a method in which vibration is applied to a soldering portion of an electrode of an electronic component by a vibrating device, the vibration propagates to a measurement probe that comes into contact with the electronic component and a pattern on a substrate. This has a large effect on the quality of the copy.

In the method of irradiating a portion to be inspected with a laser beam intermittently in the vicinity of the natural vibration frequency of the electrode of the electronic component to be inspected, if the lead is only slightly in contact with the solder, the laser beam is radiated. Therefore, it is difficult to detect a subtle lead floating because the change of the solder joint portion due to the above is small.

Further, in the method of measuring the thermal vibration phenomenon of the solder joint generated by the irradiation of the one-dimensional or two-dimensional laser light, if the lead is only delicately floating just in contact with the solder, the laser light Therefore, it is difficult to detect a subtle lead floating because the change of the solder joint portion due to the above is small.

An object of the present invention is to solve the above-mentioned problems and to provide an infrared lead floating inspection apparatus capable of reliably detecting lead floating of an electronic component.

[0017]

An infrared lead floating inspection apparatus according to the present invention comprises a heating means for heating an electronic component mounted on a substrate, and a mechanical vibration applied to the electronic component heated by the heating means. Vibration applying means, infrared image capturing means for capturing an infrared image of the electronic component heated by the heating means and to which the mechanical vibration has been applied by the vibration applying means, and captured by the infrared image capturing means. Measuring means for measuring the phase and amplitude of vibration generated in the lead portion of the electronic component when the mechanical vibration is applied by the vibration applying means based on the infrared image, and the measurement is performed by the measuring means. Determining means for comparing the phase and the amplitude with the phase and the amplitude stored in advance and when the lead portion of the electronic component is a non-defective product to determine the quality of the lead portion;

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the operation of the present invention will be described below.

In the electronic circuit package, the component to be inspected is heated from the back side of the component mounting surface, vibration is applied to the component to be inspected, and an infrared image of the component to be inspected when the vibration is applied is taken to lead the component to be inspected. By measuring the amplitude and phase of the lead, even a delicate lead floating just in contact with the solder can be reliably detected.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of one embodiment of the present invention. In the figure, an infrared lead floating inspection apparatus according to an embodiment of the present invention includes an infrared camera 1, an image processing apparatus 2, a control computer 3, a measurement processing apparatus 4, a storage device 5, a pass / fail determination unit 6, an XY Table 7, hot air nozzle 9, motor 13, rotating shaft 14, XY
And a table moving unit 15.

When inspecting lead floating of the leads 11 and 12 of the electronic component 8 mounted on the substrate 10, first, the motor 13 is driven under the control of the control computer 3, and the rotating shaft 14 and the XY table moving unit 15 are driven. By controlling the XY table 7, the electronic component 8 to be inspected is moved under the infrared camera 1.

Thereafter, the control computer 3 heats the electronic component 8 from below the substrate 10 by the hot air nozzle 9 for a certain period of time and vibrates the XY table 7 at a certain frequency.

After the heating of the electronic component 8 is completed, the infrared camera 1
The infrared image of the vibrating electronic component 8 is captured, and the infrared image is sent to the image processing device 2. The image processing device 2 performs image processing on the infrared image,
The infrared images of the leads 11 and 12 are sent to the measurement processing device 4.

The measurement processing device 4 calculates vibration information (amplitude and phase) based on the infrared images of the leads 11 and 12 input from the image processing device 2, and outputs the vibration information of the XY table 7 input from the control computer 3. , The amplitude and phase of the electronic component 8 with respect to the vibration of the XY table 7 are obtained. The obtained amplitude and phase have a great difference between the good lead 11 and the floating lead 12.

The pass / fail judgment section 6 compares the amplitude and phase obtained by the measurement processing device 4 with the amplitude and phase of a non-defective product stored in the storage device 5 in advance.
Is determined. In this case, the lead 11 is determined to be non-defective, and the lead 12 is determined to be defective.

In the embodiment of the present invention described above, the electronic components 8 are heated by hot air from the hot air nozzle 9.
However, the electronic component 8 can be heated using a hot plate or the like instead of the hot air nozzle 9.

FIG. 2 shows an electronic component 8 according to an embodiment of the present invention.
FIG. 3 is a flowchart for explaining a processing operation for obtaining the amplitude and phase of the lead, and FIG. 3 is a flowchart showing the lead floating detection processing according to an embodiment of the present invention. The lead floating detection processing according to one embodiment of the present invention will be described with reference to FIGS.

When inspecting the lead floating of the leads 11 and 12 of the electronic component 8 mounted on the substrate 10, first, the motor 13 is driven under the control of the control computer 3, and the rotating shaft 14 and the XY table moving unit 15 are driven. By controlling the XY table 7, the electronic component 8 to be inspected is moved below the infrared camera 1 (step S1 in FIG. 3).

After that, the control computer 3 blows out hot air from the hot air nozzle 9 to heat the electronic component 8 from below the substrate 10 for a certain time by the hot air (step S2 in FIG. 3), and the XY table 7
Is vibrated at a constant frequency (cycle of waveform C) (step S3 in FIG. 3). That is, the control computer 3 oscillates the XY table 7 at the pulse cycle based on the pulse generated from the pulse generator 16.

After the heating of the electronic component 8 is completed, the infrared camera 1
An infrared image of the vibrating electronic component 8 is captured (step S4 in FIG. 3), and the infrared image is sent to the image processing device 2. The image processing device 2 performs image processing on the infrared image, and sends out the infrared images of the leads 11 and 12 to the measurement processing device 4.

The measurement processor 4 obtains the amplitude and phase of the leads 11, 12 using the temperature distribution of the infrared image of the electronic component 8 from the image processor 2 (step S5 in FIG. 3).

That is, the measurement processing device 4 calculates the center of gravity G of the leads 11 and 12 in the inspection window B set for each of the leads 11 and 12 by the center-of-gravity waveform calculating circuit 17 for the image-processed infrared image A. .

In calculating the center of gravity G, the total number of pixels constituting the images of the leads 11 and 12 in the inspection window B is S, and the coordinates of the pixels are (Xi, Yi) (i = 1,...,.
n), the coordinates (Xg, Yg) of the center of gravity G are calculated from the following equation: Xg = ΣXi / S Yg = ΣYi / S Σ is the sum of i = 1 to n.

The center-of-gravity waveform calculating circuit 17 calculates the leads 11 and 12 in the inspection window B moved by vibration according to the above equation.
Are calculated, and the waveform of the center of gravity G is calculated based on the calculated center of gravity G, and is output to the phase calculation circuit 18.

The phase calculating circuit 18 calculates the phase of the center of gravity G based on the waveform of the pulse generated by the pulse generator 16 and the waveform of the center of gravity G calculated by the center of gravity waveform calculating circuit 17.
At this time, a waveform D substantially equal to the vibration waveform C of the substrate 10 is obtained for the non-defective lead 11, and a waveform E different from the vibration waveform C of the substrate 10 is obtained for the floating lead 12.

The pass / fail judgment section 6 compares the amplitude and phase obtained by the measurement processing device 4 with the amplitude and phase of a non-defective product stored in the storage device 5 in advance.
Is determined (step S6 in FIG. 3). In this case, the lead 11 is determined to be non-defective, and the lead 12 is determined to be defective. The above process is executed for all leads of the electronic component 8 to be inspected (steps S1 to S7 in FIG. 3).

If the amplitude and phase are not determined by the measurement processing unit 4, that is, if the infrared image is taken and the image of the lead to be inspected is extracted, the pass / fail judgment unit 6 has a temperature distribution range to be extracted. Otherwise, since there is no temperature propagation in the lead, it can be clearly recognized that the lead is floating.

As described above, the electronic component 8 mounted on the substrate 10 is heated by the hot air nozzle 9, and mechanical vibration is applied to the heated electronic component 8 based on the pulse from the pulse generator 16. The infrared image of the heated and mechanically applied electronic component 8 is captured by the infrared camera 1 and the vibrations generated in the leads 11 and 12 of the electronic component 8 when the mechanical vibration is applied. Is measured by the image processing device 2 and the measurement processing device 4, and the measured phase and amplitude are stored in advance and the phase and amplitude when the lead portion of the electronic component is a non-defective product is determined by the pass / fail judgment unit 6. By comparing and judging the quality of the lead portion, the omission of detection of lead floating does not occur,
Since it is possible to detect subtle lead floating, it is possible to reliably detect lead floating of the electronic component 8.

[0039]

As described above, according to the present invention, an electronic component mounted on a substrate is heated, and a mechanical vibration is applied to the heated electronic component. An infrared image of the electronic component to which the vibration is applied is taken, and the phase and amplitude of the vibration generated in the lead portion of the electronic component when the mechanical vibration is applied are measured, and the measured phase and amplitude are stored in advance. In addition, by comparing the phase and the amplitude when the lead portion of the electronic component is a non-defective product to determine the quality of the lead portion, it is possible to reliably detect the floating of the lead of the electronic component.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram for explaining a processing operation for obtaining an amplitude and a phase of an electronic component according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a lead floating detection process according to one embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 infrared camera 2 image processing device 3 control computer 4 measurement processing device 5 storage device 6 pass / fail judgment unit 7 XY table 8 electronic component 9 hot air nozzle 10 substrate 11, 12 lead 16 pulse generator 17 center of gravity waveform calculation circuit 18 phase calculation circuit

Claims (4)

(57) [Claims] A heating unit that heats the electronic component mounted on the substrate; a vibration applying unit that applies mechanical vibration to the electronic component heated by the heating unit; a heating unit that is heated by the heating unit; An infrared image capturing unit that captures an infrared image of the electronic component to which the mechanical vibration has been applied by the vibration applying unit; and the machine that uses the vibration applying unit based on the infrared image captured by the infrared image capturing unit. Measuring means for measuring the phase and amplitude of the vibration generated in the lead portion of the electronic component when a mechanical vibration is applied, and the phase and the amplitude measured by the measuring means are stored in advance and the lead of the electronic component An infrared lead floating inspection device, comprising: a determination unit for comparing the phase and the amplitude when the part is non-defective to determine the quality of the lead part. 2. The infrared lead floating inspection according to claim 1, wherein said heating means is configured to heat from a back surface of said substrate facing a mounting surface on which said electronic component is mounted on said substrate. apparatus. 3. The measuring means calculates a movement waveform of the center of gravity of the lead part in the infrared image captured by the infrared image capturing means, and measures a phase and an amplitude of a vibration generated in the lead part. The infrared lead floating inspection device according to claim 1 or 2, wherein the inspection device is configured as follows. 4. The method according to claim 1, wherein the determining unit determines that the phase and the amplitude measured by the measuring unit are different from the phase and the amplitude when the lead of the electronic component is a non-defective product. The infrared lead floating inspection according to any one of claims 1 to 3, wherein the lead portion is determined to be defective when any one of an infrared image is not obtained and an infrared image is not obtained. apparatus.