KR20020049870A - Micro switching device - Google Patents

Abstract

PURPOSE: A micro switching device is provided to prevent the incapability of a switching operation due to the abnormal transformation of structures by employing MEMS(Micro Electro-Mechanic System) structure using an electrostatic force. CONSTITUTION: First and second fixed comb electrodes(11a,11b) are arranged on an upper surface of a substrate(10) at predetermined intervals facing to each other and extended to a first direction. First and second driving comb electrodes(12a,12b) are arranged in parallel corresponding to the respective first and second fixed comb electrodes(11a,11b). A driving beam(13) is extended to a direction at right angles to the first direction and provided with at least one contact unit(14) in the central portion thereof. Both ends of the driving beam(13) are connected to the first and second driving comb electrodes(12a,12b). First and second contact terminals(15a,15b) are located on and switched by the contact unit(14) in a movement direction. Signal lines(16a,16b) are provided on the respective contact terminals(15a,15b).

Description

Micro switching device

The present invention relates to a micro switching device, and more particularly, to a micro switching device of a MEMS (Micro Electro-Mechanic System) structure using an electrostatic force.

In the conventional micro switching device of the MEMS structure using the electrostatic force, as shown in Figure 1, the drive stage 2 is located above the substrate 1, the stage 2 is a spring (3) extending from its four corners ) And the anchor 4 supporting it.

The stage 2 includes drive electrodes 2a and 2b on both sides and a contact portion 2c interposed therebetween. Positioned below the driving electrodes 2a and 2b are fixed electrodes 5a and 5b, and below the contact portion 2c, signal lines 6a and 6b for switching are positioned, and the contact portion 2c is located. The inner ends of the signal lines 6a and 6b are disposed at predetermined intervals below the s).

In the switching device as described above, the stage 2 is moved in the Z direction perpendicular to the substrate 1 by the electrostatic force between the fixed electrodes 5a and 5b and the driving electrodes 2a and 2b. Is moved toward the substrate 1 side, the contact portion 2c is brought into contact with both of the signal lines 6a and 6b to allow energization between the two signal lines 6a and 6b.

2 illustrates a stage 2 positioned above the substrate 1, a spring 3 extending from four corners of the stage 2, and an anchor supporting the same in the conventional switching device having the above structure. 4) shows the planar structure. The stage 2 and the spring 3 are integrally formed by metal.

The drawback of the conventional switching element as described above is that when the stage is operated by electrostatic force between electrodes, plastic deformation is caused in the spring when thermal expansion of the stage and the spring is caused by heat applied from the outside, and thus, the stage is An unusually large deformation in the Z direction is caused by buckling that is not in any plane parallel to the substrate and not located at the designed height.

This is because the anchor 4 is fixed to the substrate 1 having a very low thermal expansion rate compared to the stage and spring made of metal, so that the distance between the anchors 4 fixed to the substrate 1 remains almost unchanged, This very large spring and stage are caused by large thermal expansion. The large thermal expansion of the spring and the stage eventually results in a large stress at the connection between the stage and the spring and at the connection between the anchor and the spring, which is more than the yield stress which causes plastic deformation, and thus permanent deformation at such a part. This will happen.

Figure 3 shows the stress distribution in the stage and the spring according to the heat deformation when the heat of 200 ℃ as described above. In FIG. 3, a part that is brighter than other parts represents a part where stress is largely concentrated, and its brightness represents a magnitude of stress.

According to the abnormal deformation of the stage as described above, for example, when the stage is abnormally distant from the substrate or inclined to one side, the switching operation cannot occur, whereas when the stage is set close to the substrate side, the contact portion of the stage is set to both signals. There is a problem of permanent contact with the line.

Even if the above-described conventional micro switching device does not cause abnormal permanent deformation as described above, there is a possibility that the function as a switching device may be lost due to sticking phenomenon that the stage sticks to the substrate. This sticking phenomenon is caused by moisture or foreign matter generated during the manufacturing process between the stage and the substrate that maintain the interval of several micrometers.

In order to solve the above problems, a first object of the present invention is to provide a micro switching device that can effectively suppress the disablement of the switching operation due to abnormal deformation of the structure.

It is a second object of the present invention to provide a micro switching device capable of fast response speed and stable switching operation.

It is a third object of the present invention to provide a micro switching device having an extended switching function.

1 is a schematic perspective view of a conventional micro switching device.

FIG. 2 shows a planar structure of the structure by the stage and the spring in the conventional micro switching device shown in FIG.

FIG. 3 is a simulation diagram illustrating deformation of a structure and stress distribution according to thermal deformation of the conventional micro switching device illustrated in FIGS. 1 and 2.

4 is a schematic plan view of a first embodiment of a microswitching element according to the invention.

5 is a schematic plan view of a second embodiment of a microswitching element according to the invention.

6A and 6B are excerpts showing deformation states for each type of driving comb electrodes applied to a micro switching device according to the present invention.

7 is a schematic plan view of a third embodiment of a micro switching device according to the invention.

8 is a schematic plan view of a fourth embodiment of a microswitching element according to the invention.

According to the present invention to achieve the above object,

Substrate,

First and second fixed comb electrodes disposed on the upper surface of the substrate to face each other at predetermined intervals and extending in a first direction;

First and second driving comb electrodes disposed side by side corresponding to each of the first and second fixed comb electrodes;

A driving beam extending in a direction orthogonal to the first direction and connected at both ends thereof to the first and second driving comb electrodes, the driving beam having at least one contact portion at a middle portion thereof;

First and second contact terminals positioned in the moving direction of the contact portion of the drive beam and switching occurs by the contact portion;

Signal lines electrically connected to each of the contact terminals; Provided is a micro switching device.

In addition, in order to achieve the above object, according to the present invention,

Substrate,

Two driving comb electrodes disposed to face each other at a predetermined height above the substrate and extending in a first direction;

Fixed comb electrodes provided on both sides of each of the driving comb electrodes;

A driving beam extending in a direction orthogonal to the first direction and connected at both ends to the driving comb electrodes, the driving beam having at least one contact portion at an intermediate portion thereof;

First and second contact terminals positioned in the moving direction of the contact portion of the drive beam and switching occurs by the contact portion;

Signal lines electrically connected to each of the contact terminals; Provided is a micro switching device.

According to the exemplary embodiments of the present invention, the driving comb electrode has a spring shape of “” type having a portion extending in the first direction and a portion in a second direction perpendicular to the first direction, thereby fixing the driving comb electrode. The driving beam is moved in its longitudinal direction by the attraction force by the electrostatic force with the comb electrode, and is deformed and restored to a predetermined shape by its elastic force.

In addition, according to an embodiment of the present invention, the drive beams are provided with two contact portions at predetermined intervals, and each contact portion has a first and second mutually corresponding electrical switching to be selectively performed according to the moving direction of the drive beam. Two contact terminals are disposed respectively. Here, the first contact portion of both contact portions is electrically connected, thereby acting as a 1: 2 selector switch by the two contact portions.

Hereinafter, preferred embodiments of the micro switching device according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 schematically shows a first embodiment of a micro switching element according to the invention. The comb-shaped unit electrodes 11a 'extending in the first direction y and extending in the second direction x on both sides of the substrate 10 are comb-shaped first and second fixed comb electrodes 11a. , 11b) are arranged side by side at predetermined intervals in mutually opposite directions. The inside of each of the first and second fixed comb electrodes 11a and 11b is provided with a corresponding non-slip drive comb electrode 12a and 12b. The drive comb electrodes 12a and 12b also have comb-shaped unit electrodes 12a 'and 12b', and the unit of the fixed comb electrodes 11a and 11b of these comb-type unit electrodes 12a 'and 12b'. It is alternately arranged with the electrodes 11a ', 11b'.

Both ends of the driving comb electrodes 12a and 12b are fixed to the substrate, and the rest of the driving comb electrodes 12a and 12b are floating from the surface of the substrate 10 like the general driving comb electrodes.

Middle portions of the drive comb electrodes 12a and 12b are connected by a drive beam 13. The contact portion 14 is provided in the middle portion of the driving beam 13, and the first and second contact terminals 15a and 15b in which electrical on / off switching operation is performed by the contact portion 14 are provided on the substrate 10. Prepared. The first and second contact terminals 15a and 15b are connected to the first and second signal lines 16a and 16b respectively formed on the substrate 10.

FIG. 5 is a plan view of a second exemplary embodiment in which a structure of a driving comb electrode is modified in the micro switching device of Example 1 illustrated in FIG. 4.

Referring to FIG. 5, the driving comb electrode 121 may have a “c” type or “r” type unit electrode 121a ′ and 121b ′ extending alternately in a first direction y and a second direction x. Equipped. The unit electrodes 11a 'and 11b' corresponding to the fixed comb electrodes 11a and 11b enter between the unit electrodes 121a 'and 121b' of the driving comb electrode 121. In other parts, the structure is substantially the same as that described in Embodiment 1 described above.

In the micro switching device of the first and second embodiments having the above structure, the drive beam 13 is reciprocated in the longitudinal direction by the comb electrode structure as described above. The contact portion 14 provided in the middle portion is in contact with or separated from the first and second connection terminals 15a and 15b, so that an electrical signal between the first and second signal lines 16a and 16b is turned on or off. . This on / off operation is caused by the generation of a selective electrostatic force of the first and second fixed comb electrodes and the first and second drive comb electrodes corresponding to each of them. 4 and 5, a voltage having a predetermined potential (generally DC 3V) is applied to the first fixed comb electrode on the left side and the first driving comb electrode corresponding thereto to move the driving beam 13 to the left side in the drawing. The contact 14 is not yet in contact with the first and second contact terminals 15a and 15b.

The driving comb electrodes 12a, 12b, 121a, and 121b have their ends fixed to the substrate 10, so that the deformation of the middle portion of the driving comb electrodes 12a, 12b, 121a, and 121b is larger than that of the both sides. do. 6A illustrates a modified state of the drive comb electrode 12 illustrated in FIG. 4, and FIG. 6B illustrates a modified state of the drive comb electrode 12 illustrated in FIG. 5. 6A and 6B, when a force of 10 micro Newton is applied when the length of the drive comb electrodes 12 and 121 of gold (Au) is 500 micrometers, the drive comb electrode 12 shown in FIG. The displacement was 0.9 micrometer, and the drive comb electrode 121 shown in FIG. 6B exhibited a displacement of 2.4 micrometers. This spring consequently mitigates the impact between the contact portion 14 of the drive beam 13 and the first and second connection terminals 15a, 15b and at the same time quickly restores the drive beam 13 to its normal position. Makes this possible. Preferably, it is advantageous to apply the driving comb electrode of the " d " type of the second embodiment shown in FIG. That is, Example 2 has a relatively low driving voltage characteristic because the displacement is large when the same force is applied.

The switching elements of the above-described embodiments 1 and 2 are for simple on / off, and in the following, the structure of the second embodiment described together with the fifth as a micro switching element according to the present invention which can be selectively switched, that is, acts as an electrical selector switch. The third embodiment to which is applied is described, and the parts described in the previous embodiment are not described any more.

Referring to FIG. 7, first and second contact parts 14a and 14b are disposed at an intermediate portion of the driving beam 13 at which both ends of the first driving comb electrode 121a and the second driving comb electrode 121b are fixed. ) Are formed at predetermined intervals. In addition, connection terminals 151a and 151b and 152a and 152b which are switched by the first and second contact parts 14a and 14b are located outside of each other. The pair of connection terminals 151a, 151b, 152a, and 152b corresponding to the first and second contact parts 14a and 14b are selectively switched according to the moving direction of the drive beam 13. In FIG. 7, the driving beam 13 is located at a neutral position, that is, in a normal off state, and thus, the connection terminals 151a and 151b and 152a and 152b of each set are electrically off. In this state, as shown in FIG. 7, when a DC voltage having a predetermined potential is applied to the first fixed comb electrode 11a and the first driving comb electrode 121a on the left side, the driving beam may be formed by an electrostatic force therebetween. 13) moves to the left, so that the connecting ends 151a and 151b in the left direction in the drawing are electrically connected. On the contrary, when a DC voltage having a predetermined potential is applied to the first fixed comb electrode 11b and the first driving comb electrode 121b positioned on the right side of the drawing, the driving beam 13 is moved to the right by electrostatic attraction between them. Therefore, the connection ends 152a and 152b in the right direction in the drawing are electrically connected. As shown in FIG. 7, the connection terminals 151b and 152b below the driving beam 13 are electrically connected by one common signal line 161b. Therefore, depending on the position of the drive beam 13, the common signal line 161b is selectively connected to the individual signal lines 161a and 161c on the opposite side. That is, the micro switching element of the third embodiment operates as an electrical selector switch of 1: 2. On the other hand, when the common signal 161b is not applied and a separate signal line is applied to each of the connection terminals 151b and 152b, the common signal 161b does not operate as a selector switch and selectively turns on / off two independent electrical paths. It only works as a switch.

In the first, second, and third embodiments, a structure in which one driving comb electrode is applied to one fixed comb electrode has been described. Hereinafter, a fourth embodiment of the micro switching device according to the present invention to which the structure of Embodiment 3 described with reference to FIG. 7 is applied as having a structure in which two fixed comb electrodes are applied to one driving comb electrode will be described. The portions described in the embodiments of no longer described.

Referring to FIG. 8, fixed comb electrodes 11a, 11c and 11b and 11d are provided on both sides of the first and second driving comb electrodes 121a and 121b supported by both sides of the drive beam 13. . This structure provides a driving force in both directions with respect to one of the driving comb electrodes 11a and 11b to double the moving force of the driving beam.

As shown in FIG. 8, DC voltages having a predetermined potential are applied to both of the driving comb electrodes 121a and 121b and the fixed comb electrodes 11a and 11d located on the left side, and are attracted to each other by the electrostatic force therebetween. Therefore, the driving beam 13 moves to the left in the drawing, and vice versa, the driving beam 13 moves to the right in the drawing. This structure provides a moving force with respect to the drive beam 13 on both sides of the drive beam 13. Therefore, compared with the above-described embodiments, the operation speed is very fast and stable switching operation is achieved. According to this structure, since the electrostatic force is proportional to the square of the operating voltage, the driving voltage is increased compared to the above-described embodiments 1 to 3. Can be lowered by boat. As described above, in Embodiment 4 described with reference to FIG. 8, the structure in which two fixed comb electrodes are applied to one driving comb electrode is also applicable to Embodiments 1 to 3 described above.

In the micro switching device according to the present invention as described above, by applying a so-called comb-driven switching driving unit using an electrostatic force, a conventional labyrinth type spring is mixed with a comb-drive so that the switching operation is parallel to the substrate. It is supposed to be done. Therefore, the micro-switching device of the present invention applies the driving principle of the comb-drive, but is provided with a spring function for the driving beam in this structure, so that the flexibility by the spring and the large electrostatic force of the comb-drive can be used together. In addition, while the conventional micro switching device is an up / down driving method in a direction perpendicular to the substrate, the present invention is a horizontal behavior type that moves in the planar direction of the substrate to prevent so-called sticking. Can be.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be defined only in the appended claims.

Claims (6)

Substrate, First and second fixed comb electrodes disposed on the upper surface of the substrate to face each other at predetermined intervals and extending in a first direction; First and second driving comb electrodes disposed side by side corresponding to each of the first and second fixed comb electrodes; A driving beam extending in a direction orthogonal to the first direction and connected at both ends thereof to the first and second driving comb electrodes, the driving beam having at least one contact portion at a middle portion thereof; First and second contact terminals positioned in the moving direction of the contact portion of the drive beam and switching occurs by the contact portion; Signal lines electrically connected to each of the contact terminals; Micro switching element characterized in that it comprises. The method of claim 1, And the driving comb electrode has a spring shape of a "d" shape having a portion extending in the first direction and a portion in a second direction perpendicular to the first direction. The method according to claim 1 or 2, The driving beam is provided with two contact portions at predetermined intervals, and a pair of contact terminals are provided adjacent to each contact portion to selectively electrically switch according to the moving direction of the driving beam. . Substrate, Two driving comb electrodes disposed to face each other at a predetermined height above the substrate and extending in a first direction; Fixed comb electrodes provided on both sides of each of the driving comb electrodes; A driving beam extending in a direction orthogonal to the first direction and connected at both ends to the driving comb electrodes, the driving beam having at least one contact portion at an intermediate portion thereof; First and second contact terminals positioned in the moving direction of the contact portion of the drive beam and switching occurs by the contact portion; Signal lines electrically connected to each of the contact terminals; Micro switching element characterized in that it comprises. The method of claim 4, wherein And the driving comb electrode has a spring shape of a "d" shape having a portion extending in the first direction and a portion in a second direction perpendicular to the first direction. The method according to claim 3 or 4, The driving beam is provided with two contact portions at predetermined intervals, and a pair of contact terminals are provided adjacent to each contact portion to selectively electrically switch according to the moving direction of the driving beam. .