JPH0677810B2 - Optical beam soldering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a foot (lead row) of a chip-type IC mounted on a substrate via cream solder, and light from an arc heat source or the like. The present invention relates to an improvement of an optical beam soldering device for irradiating a beam and melting the solder by the heat to solder the legs of the IC to a substrate.

[Conventional technology]

An example of a conventional soldering apparatus using this type of light beam is shown in FIG. 5, which will be described below.

1 is an elliptical reflecting mirror, 2 is its first focal point F ₁ or 1st focal point F ₁
An arc heat source, which is a point light source disposed in the vicinity of, is a workpiece to be heated such as a soldering part placed at the second focal point F ₂ of the elliptical reflecting mirror 1.

The heat source radially generated from the arc heat ray 2 installed at the first focal point F ₂ of the ellipsoidal reflecting mirror 1 is reflected by the elliptical reflecting mirror 1 and focused on the second focal point F ₂ , The heating portion such as the soldering portion of the workpiece 3 to be heated placed at the focal point F ₂ is heated in a dot shape corresponding to the optical performance of the arc heat source 2 and the ellipsoidal reflecting mirror 1 to be soldered or the like. Is heat processed.

[Problems to be solved by the invention]

In the conventional light beam soldering device, since the shape of the focus of the light beam is a circular heating spot as described above, heating is required when there are several heated portions or when the heating portion is linear. Intermittent movement of the spot position or continuous linear scanning had to be performed.

Therefore, the work time becomes long and the work efficiency is poor, and the melting and solidification of the heated part is performed by changing the place one after another, so that the strain is generated in the member one after another, resulting in a large stress strain, and the displacement of the parts etc. However, there are drawbacks such as frequent occurrence of defects and deterioration of reliability.

In addition, there is a problem that if a part of the foot of the IC is bent and it floats from the board, soldering to the foot cannot be performed.

[Object of the Invention]

The present invention is to eliminate the above-mentioned drawbacks of the conventional light beam soldering apparatus, and simultaneously irradiates the legs protruding from the 2 or 4 surface of the chip type IC with the linear light beam, The cream solder in the soldering part of the IC is melted at one time, and even if the soldering positions of the IC feet and the board are slightly misaligned, the arranging effect that matches them is generated and the soldering is performed efficiently.

After self-alignment due to melting of cream solder, press the IC from above toward the board
Even if some of the feet are bent and some of the feet are floating from the board, solder all the feet tightly to the board. The purpose is to prevent defective soldering, etc. where flux gets in between.

[Outline of Invention]

In order to achieve the above-mentioned object, the present invention irradiates a light beam made into a plurality of linear spots by a cylindrical lens to the entire feet of a chip-type IC, and from above the IC after self-alignment by solder melting. The gist is to provide a pusher that presses the IC onto the substrate.

Example of Invention

Next, one embodiment of the present invention will be described with reference to FIGS.
This will be described below.

In FIG. 1, 4 is an arc heat source lamp, 5 is its point light source, 7 is its anode, 8 is its cathode, and anode 7 and cathode 8 are shown.
Is connected to a lamp power source (not shown), and the point light source 5 is turned on.

Reference numeral 6 denotes an elliptical reflecting mirror, on which the arc heat source lamp 4 is installed so that the point light source 5 is located at or near the first focal point, and reflects the heat light source from the point light source 5.

Reference numeral 9 is a first plane mirror that reflects the reflected light from the elliptical reflecting mirror 6, and 10 is a second plane mirror that reflects the reflected light from the first plane mirror 9, and the angle and position thereof can be finely adjusted. A mechanism is attached, and the second plane mirror 10 can be slightly moved in the left-right direction in the drawing by the moving mechanism 11.

Reference numeral 12 denotes a cylindrical lens installed in the reflected light path of the second plane mirror 10. The cylindrical lens 12 is held at a constant angle and can be finely moved in the horizontal direction in the drawing by a moving mechanism 13.

14 is installed in the reflected light path of the second plane mirror 10,
As shown in the figure, two pairs of shading plates are used. By changing the interval, the cylindrical lens 12
The width of the reflected light that reaches is stretched.

By the opening / closing mechanism 15 for adjusting the width, the shading plate 14 can be finely moved in the horizontal direction in the drawing in synchronization with the moving mechanism 13 in addition to the above-mentioned width adjustment of the reflected light and the total shading. The lens 12 is always kept at a constant interval.

First plane mirror 9, second plane mirror 10, moving mechanism described above
The optical system composed of 11, 13 and the cylindrical lens 12 and the light shielding plate 14 is arranged in four directions perpendicular to the center line of the elliptical reflecting mirror 6.

16 is a heat-resistant shield glass for protecting the optical system inside the device from gas or dust generated by processing, 21
Is an inlet of a cooling fluid fed into the inside of the apparatus from a cooling fluid generator not shown.

An air cylinder 22 for a pusher is attached below the arc light source lamp 4.

A plunger 24, which is pushed upward by a spring 23, is accommodated in the air cylinder 22, and when compressed air is introduced into the air cylinder 22, the pressure causes the plunger 24 to move.
Is pressed against the spring 23.

A small piston 26, which is pushed downward by a spring 25, is accommodated in the plunger 24.When the small piston 26 hits an object when the plunger 24 descends as described above, the small piston 26 is spring-loaded. It is pushed up against 25 and pushes the hit object with the pressing force of the spring 25.

Next, the operation of this device will be described.

The heat ray radially generated from the point light source 5 is reflected by the elliptical reflecting mirror 6 to form an optical path a, and is reflected in four directions by the four first plane mirrors 9 to form an optical path b.

The light ray on the optical path b is further reflected by the second plane mirror 10 to form an optical path c and enter the cylindrical lens 12.

The cylindrical lens 12 is set at an angle perpendicular to the optical path c and at a position where a light beam can be sufficiently incident, and the heat ray linearly condensed by the cylindrical lens 12 in one direction is , The electronic component that is the work piece
Irradiate as a linear spot 17 near the lead wire of 18.

FIG. 2 shows the irradiation situation of the linear spot 17 around the lead wire of the electronic component 18, and since the paste solder is applied to this portion on the circuit board 19 in all the steps, this irradiation The solder is melted and soldered.

Therefore, the only heat effect on the electronic component 18 is the heat conduction through the lead wire.

As described above, since all the lead wires of the electronic component 18 are simultaneously irradiated with the heat source, the solder for soldering all the lead wires is melted at the same time.

Therefore, even if the positions of the lead wires of the electronic component 18 and the pattern of the circuit board 19 are slightly misaligned, the electronic component 18 is self-moving so that the position of the lead wire and the amount of putter match due to the surface tension of the molten solder. Produces an alignment effect.

In this way, when the solder melts and the self-alignment effect occurs, compressed air is introduced into the air cylinder 22 and the plunger 24 is lowered.

At this time, when the plunger 24 has finished descending, the small piston
The height of the circuit board 19 is set so that the small piston 26 is slightly pushed into the plunger 24 by hitting the upper surface of the electronic component 18 with the electronic component 18.

Therefore, the electronic component 18 is pressed by the spring 25 so that the circuit board 19
Pressed against.

Therefore, even if some of the lead wires of the electronic component 18 have an error or deviation in the bending angle, these are corrected and the pressing force of the spring 25 is adjusted so that all the lead wires come into contact with the circuit board 19. Will work.

At the time when the pressing of the electronic component 18 by the small piston 26 is started, the irradiation of the heat ray is stopped, the cooling of the solder is started by the blowing of air and the solder is solidified, and then the compressed air in the air cylinder 22 is compressed. Is removed, the plunger 24 is raised by the force of the spring 23, and the pressing of the electronic component 18 is released.

Next, a case where the size of the electronic component 18 or the shape of the soldering portion is changed will be described.

First, in order to change the position of the linear spot 17, the moving mechanisms 11 and 13 are set to move the second flat mirror 10 and the cylindrical lens 12 of the optical system facing each other in association with each other in the reflection direction. There is.

Therefore, the linear spots 17 are
a and 17a and 17b and 17b move in the opposite directions to increase or decrease the distance between them, which corresponds to the change in the soldering position.

Two light shields to change the length of the linear spot 17.
Each of 14 is moved in the direction of the arrow in FIG. 4 to increase or decrease the distance between them, so that the optical path c incident on the cylindrical lens 12 is appropriately shielded.

As a result, the length of the outgoing light beam that is not condensed by the cylindrical lens 12 is adjusted to adjust the length of the linear spot 17.

Then, when the soldering position is only on the opposite side of the electronic component 18, one of the opposing linear spots 17a, 17b is totally shielded by the light shielding plate 14, and the linear spot not shielded.
Heat processing only with 17a or 17b to prevent heating of unnecessary parts.

In the above embodiment, the moving mechanisms 11 and 13 and the opening / closing mechanism 15
Each has an independent drive source and operates by this. However, one drive source may be configured to have a constant operation ratio by a reduction mechanism and be synchronized with each other.

Further, although the ellipsoidal reflecting mirror 6 is used, a parabolic reflecting mirror may be used, and in this case, the reflected light rays are close to parallel light rays, so that the first plane mirror 9 and the second plane mirror 10 are used. ,
The installation status of the cylindrical lens 12 also needs to be changed accordingly.

Further, in the above embodiment, four linear spots 17 are formed by four optical systems, but the number of optical systems may be increased or decreased depending on the number of portions to be heated to adapt to the work. it can.

〔The invention's effect〕

As described above, the present invention irradiates a plurality of linear spots of a light beam onto all the feet of a chip-type electronic component at the same time,
All cream solder can be melted at one time and the soldering can be done at once.

The surface tension generated when the solder is melted at the same time enables accurate soldering due to the self-alignment effect that corrects the displacement between the foot and the substrate, and the soldering ability can be significantly improved.

Moreover, since the pusher pushes the electronic component from above after the self-alignment effect is generated, even if any of the legs is bent or out of alignment and all the legs cannot contact the substrate, keep them in close contact. Is something that can be done.

Therefore, defective soldering due to floating of the feet and defective soldering such as defective soldering in which flacks enter between the pattern of the foot and the board are prevented, and complete soldering can be performed.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a plan view showing a state of linear spots, FIG. 3 is a sectional view of a pusher portion, FIG. 4 is a front view of a light shielding plate portion, FIG. 5 is a principle diagram of a conventional light beam soldering apparatus. 4 ... Arc light source lamp, 6 ... Elliptical reflector, 9 ...
1st plane mirror, 10 ... 2nd plane mirror, 12 ... Cylindrical lens, 14 ... Shading plate, 17 ... Linear spot,
18 …… Electronic parts, 22 …… Air cylinder, 24 …… Plunger, 26 …… Small cylinder.

Claims (1)

[Claims] 1. A light beam soldering device for irradiating a lead beam of an electronic component, which is temporarily fixed on a circuit board with cream solder, with a light beam to solder the electronic component onto the circuit board. One quadric surface reflecting mirror having an elliptical surface or a parabolic surface that collects and reflects the light from the heat source lamp, and splits the reflected light from the one quadric surface reflecting mirror into a plurality of directions. A plurality of first plane mirrors and a plurality of first plane mirrors, each of which is arranged in a one-to-one correspondence with the plurality of first plane mirrors, and which reflects the reflected light from the corresponding first plane mirror toward the cylindrical lens. The two plane mirrors are arranged in a one-to-one relationship with the plurality of second plane mirrors, and the reflected light from the corresponding second plane mirrors is condensed only in one direction to form a linear light beam. Then temporarily fixed on the circuit board A plurality of cylindrical lenses that form spots of heat rays on corresponding lead rows of the electronic component; and a pusher that presses the electronic component temporarily fixed on the circuit board from above toward the board. The optical beam soldering device according to claim 1, wherein the pusher is activated after the cream solder is melted by the irradiation of the light beam to press the electronic component.