JPH0494140A - Small-sized part holding mechanism - Google Patents

Abstract

PURPOSE:To precisely modify the direction of the held part by equipping it with the second support, which supports, capably only in the rotation around the axis, the first supporting a parts holder capably only in unidirectional shifting and is fixed to a unidirectional shifting means, a biasing means, which biases the parts holder to the table side, and a mechanism, which changes the direction of the first support while regulating the degree of freedom of the first support. CONSTITUTION:The second housing 6 is lowered until the element A sucked by a pincette 3 draws near right above the junction target B fixed to a table 15 by driving a shifting mechanism 7. Next, the direction of the element A is modified by driving the motor 10 coupled to the second housing 6. The inclination and the horizontal positioning of the junction target B are performed by the adjustment of the table 15. When such adjustment is completed, the second housing is lowered by driving the shifting mechanism 7 again so as to push the element A against the object A to be joined. At this time, by the reaction of this pushing, the movable axis 1 retreats upward resisting the energization of a coil spring 12, and proper pressure, which is set with a micrometer 14, is given to the element A.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a small component holding mechanism that is effective for high precision bonding of small components such as optical elements, for example, junction down bonding of multi-beam semiconductor lasers. It is.

(Prior Art) Conventionally, as this type of small component holding mechanism, the mechanism shown in Fig. 2(a) is used.
Or the one shown in (b) is known.

The small component holding mechanism shown in FIG. 2(a) has a thin cylindrical bottle set 20 with a tapered lower end, and the upper end of the bottle set is connected to a vacuum pump (not shown) via a flexible hose 21. ing.

Further, the bottle set 20 has a vacuum suction hole 20a passing through its center, so that a small component, such as an optical element A, can be sucked and held by driving a vacuum pump. The bin set 20 is vertically supported by an arm rod 23 that extends horizontally from a moving mechanism section 22 that is vertically movable. Thereby, the element A held by the tweezers 20 can be pressed against the object to be welded B placed on the table 24 provided below. Further, the table 24 has a heating function and is capable of melting the solder C placed on the joint surface of the object B to be joined.

Further, the small component holding mechanism shown in FIG. 2(b) has a movable shaft 25 which is vertically movable and has a tweezers 20 similar to those described above attached to the lower end thereof. A coil spring 26 that urges the movable shaft 25 downward is connected to the upper end of the movable shaft 25, so that it can absorb excessive pressing force applied when joining the elements. The moving mechanism section 22 similar to that described above has an arm section 27 that extends horizontally, and a movable shaft 25 is slidably inserted into a bearing hole 27a provided in the arm section 27. On the other hand, the rotation of the movable shaft 25 in the horizontal direction is restricted by inserting a detent pin 29 fixed to the arm portion 27 into a hole 28a of a detent plate 28 extending horizontally from the top thereof.

The arm portion 27 also has a vacuum suction hole 27 whose end opens in a part of the inner surface of the bearing hole 27a and whose other end communicates with the vacuum pump.
b is formed. On the other hand, the movable shaft 25 is formed with a communication hole 25a whose one end opens to the vacuum suction hole 27b of the bearing hole 27a and whose other end communicates with the vacuum suction hole 20a of the tweezers 20. As a result, the same joining operation as described above can be performed, and since the movable shaft 25 retreats upward against the biasing force of the coil spring 26 when joining the elements, a predetermined pressing force is always applied to the element A. .

(Problem to be Solved by the Invention) By the way, when bonding is performed using the above-described mechanism, the table 24 will be heated to about 320°C since the melting point of the solder C is about 300°C.

For this reason, in the case of the former small component holding mechanism, thermal expansion of the arm rod 23 and the like causes relative displacement between the element A and the object to be bonded B in a direction parallel to the table 24, making accurate positioning difficult. Ta. In addition, since the former small component holding mechanism does not have any means for absorbing the pressing force at the time of joining the elements, there is a risk that the element A may be damaged by the excessive pressing force at the time of joining. Therefore, it is not suitable for high-precision bonding of semiconductor lasers and the like.

In addition, the latter small component holding mechanism is superior to the former in that it can control the pressing force applied to the element A by the movable shaft 25, but it does not require frictional resistance to adjust the pressing force down to a few grams. In order to reduce the gap, the bearing has a gap of 0.1m.
The anti-rotation plate 28 is designed to be larger than m.
The fitting clearance between the hole 28a and the rotation pin 29 is also large. For this reason, there was a problem in that the tweezers 20 rattled and the element A was likely to be misaligned during bonding.

Further, since the vacuum suction hole 27b of the arm portion 27 opens in a part of the inner surface of the bearing hole 27a, when the vacuum pump suctions the movable shaft 25 to the opening side, the sliding resistance increases. However, there is also the problem that it is difficult to obtain accurate pressing force. Furthermore, since the movable shaft 35 returns to a free state by canceling the vacuum suction after pressing the element A against the object B to be welded, there is a possibility that the tweezers 20 may shake when the suction is canceled.

Further, like the former small component holding mechanism, there is also an effect due to thermal expansion of the arm portion 27 and the like. Therefore, it cannot be said that the latter small component holding mechanism can sufficiently support high-precision bonding.

Furthermore, since neither of the small component holding mechanisms can correct the orientation of element A held by the tweezers 20 in the direction parallel to the table 24, there remains some concern regarding the accuracy of positioning in this direction. Ta.

The present invention has been made in view of the above-mentioned problems, and its purpose is to eliminate positioning errors during bonding due to the effects of thermal expansion and mechanical play, and to provide a compact device that is sufficiently compatible with high-precision bonding. The object of the present invention is to provide a component holding mechanism.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides the following in claim (1):
A small component holding mechanism in which a component holder capable of detachably holding a small component such as an optical element is provided at the lower end of the component holder, which is movable in a direction perpendicular to a table on which an object to be joined with the small component is placed. , a first support portion that supports the component holding portion so as to be movable only in a direction perpendicular to the table;
A second support part that supports the first support part so as to be able to rotate only about an axis perpendicular to the table of the component holding part, and is fixed to a moving means in a direction perpendicular to the table; The apparatus includes a biasing means for biasing the first support part to the side, and a mechanism for changing the direction of rotation of the first support part while restricting free rotation of the first support part.

Further, in claim (2), the first and second support portions include:
Each of them is provided around the component holding part as a center, and is formed with a uniform thickness in a direction parallel to the table.

Moreover, in claim (3), a heat shielding plate is provided between each of the support parts and the table.

(Function) According to the small component holding mechanism of claim (1), the component holding part that holds the small part is supported by the first support part so that it can move only in the direction perpendicular to the table. The holding part does not move in a direction parallel to the table. Further, since the first support part is supported by the second support part so as to be rotatable only about an axis that is perpendicular to the table and centered on the component holding part, the first support part is rotated in a direction perpendicular to the table. It does not move and its free rotation is restricted.

Furthermore, the mechanism for changing the rotational direction of the first support section allows the orientation of the component held in the component holder to be corrected. Furthermore, as mentioned above, the component holder supported so as to be movable in the direction orthogonal to the table is biased toward the table, so when the component is pressed against the object to be welded, the component holder responds to the biasing force. , and only a pressing force corresponding to the biasing force is applied to the component.

Further, according to the small component holding mechanism of claim (2), when the objects to be welded are heated on the table during welding, the first and second support portions receive the heat and undergo thermal expansion. Since each support part is formed around the component holding part with uniform thickness in the direction parallel to the table, the thermal expansion of each support part in this direction occurs uniformly around the component holding part, Displacement of the component holding portion in this direction hardly occurs.

Further, according to the small component holding mechanism of claim (3), the heat generated by heating the objects to be welded is blocked by the heat shield plate provided between each of the supports and the table. Thermal expansion of the area is suppressed.

(Embodiment) FIGS. 1 and 3 show an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a cylindrical movable shaft that is long in a direction orthogonal to a table 15 (described later), that is, in a vertical direction, and is supported by a first housing 4 (described later) so as to be movable in the vertical direction. The upper end of the movable shaft 1 is connected to a vacuum pump (not shown) through a flexible tube 2, and tapered tweezers 3, which serve as an element holding part, are attached to the lower end of the movable shaft 1. The tweezers 3 have a vacuum suction hole 3 penetrating through their center.
a is formed, and the upper end of the vacuum suction hole 3a communicates with the central through hole 1a of the movable shaft 1. This makes it possible to attract and hold the element A at the lower end of the tweezers 3 by driving the vacuum pump.

A first housing 4 serves as a support for the movable shaft 1, and is rotatably supported by a second housing 6, which will be described later, about the movable shaft 1 as a central axis. The first housing 4 has a cylindrical shape that extends vertically along the outer surface of the movable shaft 1 and has a uniform wall thickness. Furthermore, rolling bearings 5 are interposed near the upper and lower ends of the inner surface of the first housing 4, respectively, to support the movable shaft 1 so as to be movable in the vertical direction. The guide groove 1b of the ball 5a of the rolling bearing 5 is formed vertically along the side surface of the movable shaft 1, and the engagement of the guide groove 1b and the ball 5a prevents the movable shaft 1 from rotating.

A second housing 5 serves as a support for the first housing 4, and its side surface is fixed to a moving mechanism 7 similar to the conventional one. The second housing 6 has a cylindrical shape that extends vertically along the outer surface of the first housing 4 and has a uniform wall thickness. In addition, there are first holes near the upper and lower ends of the inner surface, respectively.
A rolling bearing 8 is interposed to rotatably support the housing 4 and to restrict movement of the first housing 4 in the vertical direction. On the other hand, a gear 9 is attached to the upper end of the first housing 4 and is perpendicular to the axis thereof. This gear 9 meshes with a worm gear 11 connected to a motor 10 which is fixed to a mounting member (not shown) and is rotatable in forward and reverse directions. As a result, the motor 10 is driven to drive the first housing 4.
By rotating the tweezers 3, the tweezers 3 rotate, and the orientation of the element A held by the tweezers 3 can be corrected in the circumferential direction of the tweezers 3.

A coil spring 12 urges the movable shaft 1 toward a table 15 (to be described later), that is, downward, and its lower end is connected to an arm rod 13 provided perpendicularly to the upper portion of the movable shaft 1. Further, the upper end of the coil spring 12 is connected to a micrometer 14 provided above it.
By setting the micrometer 14, the pressing force when bonding the elements can be finely adjusted.

Reference numeral 15 denotes a stage for mounting and fixing the object B to be welded of the element A, and is installed below the tweezers 3. This stage 15 has a heating function and can heat the solder C placed on the joint surface of the object B to be joined until it melts. Further, the table 15 is also capable of adjusting its inclination and horizontal position.

Here, the operation of the small component holding mechanism configured as described above during element bonding will be explained.

First, the moving mechanism section 7 is driven, and the welding object B is fixed to the stage 15, with the element A held by suction on the forceps/soto 3.
Descend No. 271 Uzing 6 until you are immediately above the top.

Next, the motor 10 connected to the second housing 4 is driven to correct the orientation of the element A. Further, the inclination and horizontal positioning of the welding object B are determined by adjusting the table 15. When each adjustment is completed, the moving mechanism section 7 is driven again to lower the second housing 6, and the element A is pressed against the object B to be welded. At this time, the movable shaft 1 retreats upward against the bias of the coil spring 12 due to the reaction caused by this pressing, and an appropriate pressing force set by the micrometer 14 is applied to the element A. In this way, according to the small component holding mechanism of this embodiment, the tweezers 3 that hold the element A
The movable shaft 1 to which the movable shaft 1 is attached is restricted from rotating in the circumferential direction by the balls 5a of the rolling bearing 5 and the guide groove 1a, and the first housing 4 also meshes with a gear 9 attached to its upper end. Motor 1 by worm gear 11
Rotation other than 0 movement is restricted. Further, the movable shaft 1 is supported by a rolling bearing 5 interposed between the first housing 4 and the 171st housing 4 is supported by a rolling bearing 8 interposed between the second housing 6. While ensuring smooth movement, conventional bearings do not cause rattling due to gaps or the like. Therefore, the tweezers 3 can be held in a stable posture at all times, and displacement of the element A can be reliably prevented. Incidentally, instead of providing the rolling bearing 5 of the first housing 4, spline protrusions may be provided on the movable shaft 1 and the first housing 4, respectively, and engaged with each other.

Furthermore, since the first housing 4 is configured to be able to rotate forward and backward by driving the motor 10, the orientation of the element A held in the tweezers 3 can be adjusted as appropriate in the circumferential direction of the tweezers 3, allowing for more accurate positioning. It can be performed.

On the other hand, since each housing 4.6 has a cylindrical shape with a concentric axis sequentially formed around the movable shaft 1 with uniform wall thickness in the direction parallel to the table 15, the thermal Displacement, that is, thermal expansion in the direction parallel to the table 15, occurs uniformly around the movable shaft 1, and displacement of the movable shaft 1 in this direction is difficult to occur.

Therefore, even in a wide temperature range due to the heating of the plate 15, there is almost no influence from the thermal expansion of each housing 4.6.

Figure 3 is a characteristic diagram of a prototype that embodies the above embodiment.
30 minutes above the ceramic welding object heated to 20℃
The horizontal displacement of element A was measured with a laser by approaching element A to 0 μm, and the values are shown for each time. As a result, even after 10 minutes, which is a sufficient time for normal bonding, the displacement was as small as just over 1 μm, and it was confirmed that the bonding was sufficient for highly accurate bonding.

Incidentally, in the above embodiment, when joining the element A, the object to be joined B is
However, since other small parts that do not require heating for joining are not affected by thermal expansion, the first and second housings 4 and 6 are arranged as cylinders with concentric axes as described above. It is not necessary to form it into a shape.

Further, as a modification of this embodiment, a flange-shaped heat shielding plate attached to the upper end of the tweezers 3 or the like may be provided between each housing 4.6 and the table 15. This not only makes it possible to further enhance the effect of the above embodiment against thermal expansion, but even if each housing does not have a structure compatible with thermal expansion, providing such a heat shield plate will reduce the thermal expansion. Displacement can be suppressed.

(Effects of the Invention) As explained above, according to the small component holding mechanism of claim (1), the mechanical play of the component holding section and each support section can be eliminated, and the direction of the held component can also be accurately determined. Can be fixed.

Furthermore, according to claims (2) and (3) the small component holding mechanism, in addition to the effect of claim (1), thermal displacement in the positioning direction does not occur even when heated during component joining. .

Therefore, we are working on junction down bonding of multi-beam semiconductor lasers, which will be in increasing demand in the future, and O8L (Opt
It can fully support high-precision bonding essential for the mounting of ultra-small optical heads or the joining of similar small parts.

[Brief explanation of drawings]

FIG. 1 is a side view of a small component holding mechanism showing an embodiment of the present invention, FIGS. 2(a) and (b) are side views of a small component holding mechanism showing a conventional example, and FIG. 3 is a side view of a small component holding mechanism showing an embodiment of the present invention. FIG. 4 is a displacement characteristic diagram of a movable shaft with respect to thermal expansion in an example. In the figure, 1... movable axis, 3... bin set, 4...
First housing, 5, 8... Rolling bearing, 6... Second housing, 7... Moving mechanism section, 9... Gear, 1
0...Motor, 11...Worm gear, 12...
Coil spring, 15...Table, A...Element, B.
・Object to be joined. (a) Figure 1 Figure 2

Claims (3)

[Claims] (1) A small component having a component holder that can detachably hold a small component such as an optical element at its lower end and is movable in a direction perpendicular to the table on which the object to be welded is placed. In the holding mechanism, a first support part that supports the component holder so that it can move only in a direction perpendicular to the table; and a first support part that supports the first support part so that it can only rotate about an axis that is perpendicular to the table of the component holder. a second support part fixed to a moving means in a direction perpendicular to the table; a biasing means for biasing the component holding part toward the table; A small component holding mechanism characterized by comprising: a mechanism for changing the rotational direction of a first support part. (2) The compact device according to claim (1), wherein the first and second supporting portions are each provided around the component holding portion as a center, and each is formed with uniform thickness in a direction parallel to the table. Parts retention mechanism. (3) The small component holding mechanism according to claim (1) or (2), further comprising a heat shield plate provided between each of the support parts and the table.