JPS58122175A - Soldering device - Google Patents

Abstract

PURPOSE:To facilitate constant soldering, and to elevate reliability of automation, by detecting radiation light of a part to be soldered, and monitoring a temperature of the said part. CONSTITUTION:An electric power source 2 is controlled as to supply of power to a CO2 laser 1, and an output of the laser 1 is condensed to a part to be soldered 4 by a lens 3. To a lead wire part 7 of electric parts 6 placed on a printed board 5, solder is applied in advance. A lens 8 condenses radiation light from the part to be soldered 4 to a detector 9, and a signal processor 10 amplifies an output of the detector 9 as necessary, and after a constant interval of time after intensity of a signal has reached a specified level, or when it has reached a specified level, a signal for stopping the supply of power to the laser is sent out to the electric power source 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to soldering using a CO laser.

With the recent increase in the density of printed circuit boards and the frequent use of flat package ICs, it has become difficult to solder components onto printed circuit boards using the conventional solder dip method.

Recently, the use of focused CO laser beams for high-density soldering has become easier to automate.

However, the existing CO laser soldering involves irradiating CO laser light for a predetermined period of time, and the soldering target depends on the heat capacity of the component, the thickness and length of the lead wire, and the printed board. Thoughts on Land's area cape
[was not paid. Additionally, the amount of solder applied to the lead wires and the like in advance varies, making it difficult to perform reliable soldering with current equipment.

The object of the present invention is to eliminate the above drawbacks and provide a reliable automatic soldering device.

According to the present invention, one of the areas irradiated with the CO laser
! The tool detects the rise in temperature and stops the CO laser irradiation when the required temperature is reached, allowing for smooth soldering at all times, regardless of the differences in the conditions of the parts to be soldered.

According to the present invention, there is a means for irradiating a CO laser beam with a wavelength of 10 μm, and a means for detecting radiant light of less than 10 μm emitted from the irradiation part, and when the intensity of the radiant light reaches a preset nine value, or Further preset time after reaching the preset value! ! After meeting the above CO
A soldering device is obtained which includes means for stopping irradiation of laser light.

Figure 4 shows the temperature of the solder applied to the lead wire when it is heated with a constant power, and is initially at room temperature (
The solder at temperature T ) rises and rises over time, and when it reaches the melting point (T ), it remains at the melting point until all the solder melts, and then the temperature continues to rise. Coupling is carried out after a certain time after reaching , or when the temperature further increases after melting and reaches a certain temperature (T, ). The jI2 diagram shows the radiation light emitted from the solder part with wavelength on the horizontal axis and intensity on the vertical axis, and uses the temperature of the solder part as a parameter. This is due to the radiating side ′″″T of the blank. However, b is a blank constant, C is the speed of light, λ
is the wavelength, k is the Boltzmann constant, and T is the temperature. The parameters in the figure are T ) T□. Room temperature (27℃=3
The wavelength that gives the maximum intensity at
The wavelength that gives the maximum intensity at is λ=9.7 μm. What should be noted here is that as the temperature rises, the wavelength that gives the maximum intensity shifts to the shorter wavelength side, and at the same time, the intensity of the radiated light itself increases.For example, the wavelength of the C02 laser light It also detects short wavelength radiation light.
As the temperature rises, the signal strength decreases significantly.

The reason why the wavelength of the CO laser is excluded from the detection target is to avoid the influence of reflection or scattered light of the CO□ laser light from the solder part. The temperature of the soldered part is detected by the above detector, and after a certain period of time has passed after reaching T, or when the expanded temperature reaches T.
If heating by the CO8 laser is stopped when the temperature is reached, the soldering will be completed.

Next, the present invention will be explained in detail using the drawings.

FIG. 3 shows an embodiment of the present invention, in which the laser 1 is a CO□ laser with a wavelength of 10 μm and an output of about 30 W, and is supplied with necessary power and gas by a power source 2. power supply 2
can control the power supply to the laser by an external signal. The output of the laser is focused by a lens 3 onto a portion 4 to be soldered. In this embodiment, the part 4 to be soldered is placed on a printed circuit board 5 and is depicted as a lead wire part 7 of a good electrical component 6 in the figure. Solder is applied to the lead wire portion 7 in advance. The lens 8 is a lens that focuses the radiation light from the soldering part 4 onto the detector 9. The material of the lens 8 may be any material as long as it transmits a desired wavelength band of 10 μm or less, such as quartz, etc. KH2-5, Irtra
The detector 9 may be made of n@O material; the detector 9 may be made of Ge doped with various impurities, or Pb8;
It may also be a thermal detector such as a 1P < 4 element in which a filter that cuts wavelengths of m or more is inserted in the front surface. Signal processing unit
O amplifies the output of the detector 9 as necessary, and sends a signal to the power supply 2 to stop power supply to the laser after a certain period of time after the signal strength reaches a certain level or when the signal intensity reaches a certain level. It's something to bring out.

In this example, the soldering mechanism using C02 radar is already a well-known method, but since the temperature of the soldered part is monitored by detecting the radiation light from the soldered part 4, Constant soldering is possible without being affected by variations in temperature rise due to differences in heat capacity due to differences in the size of the board 50 land, the size of the lead wire portion 7 of the electrical component 6, and the amount of solder disposed of. This can improve reliability in soldering automation.

In the above embodiment, the laser output is controlled by the power source 2, but a mechanical, electro-optic, or acousto-optic shutter is inserted into the output of the laser l to control the laser output externally. Alternatively, other condensing means such as a concave reflector may be used instead of the lens 8. Furthermore, if the output of the detector 9 is poor at 87N, it goes without saying that it is possible to employ means to improve the 87N, such as a tweezers and a lock-in amplifier.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the change in temperature of the soldering part, Figure 2 is a diagram showing the relationship between the radiation light from the soldering part and the wavelength, and Figure 3 is a diagram showing an example of the present invention. be. 1... CO laser, 2... Power supply, 3,
8... Lens, 4... Soldering part, 5
...Printed board, 6...Electrical parts, 7
...Lead wire section, 9...Detection. equipment, 10...signal processor. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] A CO laser, a means for condensing a beam 2 from the CO laser, and a light having a wavelength less than the wavelength of the CO laser among the radiant light of a region irradiated by the wrinkle-condensed beam. A means for collecting light within a certain band or a certain wavelength and detecting its intensity; and a means for detecting the intensity of light within a certain band or a certain wavelength. and means for stopping the output of the C02 laser when the output of the C02 laser is exceeded or exceeds a predetermined value.