KR20140139682A - Electromagnetic actuator - Google Patents

Abstract

An electromagnetic actuator includes: a moving part which includes a moving structure which is located in the opening region of a substrate and moves with a rotation shaft in the extension direction of an elastic body connected to the outside, and a conductive coil which generates a driving force for the driving structure by the interaction with a magnetic field due to the flow of a driving current; and a magnetic field generation part which is located in the lower part of the moving part, generates the magnetic field, and includes a first region and a second region which have opposite magnetic poles to each other in the upper surface based on a reference line intersecting with the rotation shaft with an acute angle in a floor plan, a third region which has an opposite magnetic pole to the first region in the outside of the first region, and a forth region which has an opposite magnetic pole to the second region in the outside of the second region.

Description

[0001] Electromagnetic actuator [0002]

The present invention relates to an electromagnetic force actuated actuator.

In addition to the development of optical device technology, a variety of technologies using light as an input / output unit of various information and as an intermediary for information transmission are being developed. Such as barcode scanner or basic level scanning laser display A typical example is a technique in which a beam from a light source is scanned and used.

In particular, recently, a system using beam scanning with a high spatial resolution has been developed. Such systems include a projection display system having high resolution and high reproducibility of primary color using laser scanning, A head mounted display (HMD), and a laser printer.

Such a beam scanning technique requires scanning mirrors having various scanning speeds and scanning angles (angular displacement, angular displacement, tilting angle) according to application examples. In the conventional beam scanning, a galvanic mirror ) Or a rotating polygon mirror and the angle of incidence between the reflecting surface of the mirror and the incident light.

When a galvanic mirror is used, a scanning speed of about several to several tens of hertz (Hz) can be realized, and it is possible to realize a scanning speed of several kilohertz (kHz) when a polygon mirror is used. That is, in the case of the polygon mirror, since the polygon mirror is mounted on the motor rotating at a high speed, the scanning speed is proportional to the rotation angular speed of the polygon mirror, which depends on the rotating speed of the moving part motor, There is a limitation in increasing the scanning speed and it is difficult to reduce the volume and power consumption of the entire system. In addition, the mechanical friction noise of the drive motor unit must be fundamentally solved, and it is difficult to expect cost reduction due to the complicated structure.

On the other hand, in the case of a scanning device using a micro mirror, bidirectional scanning is possible and a scanning speed as fast as several tens of kHz can be achieved. Such a micromirror corresponds to a magnetically driven actuator using a Lorentz force as a driving force.

The scanning micromirror implemented by the electromagnetically driven actuator will be described with reference to Fig.

1, a conventional micromirror 10 is provided with a conductive coil 40 in the form of a loop along the periphery of a mirror plate 20, And two magnets 51 and 52 are arranged so as to face each other.

In this case, the Lorentz force generated by the interaction between the magnetic field H between the two magnets 51 and 52 and the current flowing through the conductive coil 40 causes the rotation axis in the direction perpendicular to the direction of the magnetic field H The mirror plate 20 can be rotated at a predetermined angle around the center axis RA.

In this way, in the conventional micromirror, two magnets for generating a magnetic field are disposed on the same plane as the mirror plate with the mirror plate therebetween. Accordingly, the two magnets should be spaced at least beyond the width of the mirror plate. Therefore, there is a limitation in the strength of the magnetic field acting on the conductive coil, and as a result, there is also a limit to the driving of the mirror plate.

The present invention has a problem to provide a method of effectively improving the strength of a magnetic field acting on a conductive coil.

In order to achieve the above-mentioned object, the present invention provides a movable structure, which is driven by an axis of rotation of an elastic body located in an open region of a substrate and connected to an outer side thereof as a rotation axis, A movable portion including a conductive coil for generating a driving force for the movable portion; First and second regions located below the movable portion and generating the magnetic field, the first and second regions having mutually opposite magnetic poles on the upper surface with reference to a reference line intersecting at an acute angle with the rotation axis in plan view; And a magnetic field generating portion including a magnetic field generating portion including a third region having a magnetic pole opposite to the first region on the upper surface and a fourth region having a magnetic pole on the upper surface opposite to the second region outside the second region do.

Here, each of the first and second regions may have a polygonal or semicircular shape, and the third and fourth regions may be configured to surround the first and second regions.

Each of the first and second regions may be configured to extend to both sides of the magnetic field generating portion along the reference line.

The magnetic field generator may include first to fourth magnets corresponding to the first to fourth regions and magnetized in the vertical direction.

The reference line may intersect at an angle of 45 degrees with respect to the rotation axis.

The movable structure may be connected to the substrate through the elastic body, and the conductive coil may be installed in the movable structure.

And a movable frame connected to the movable structure through the elastic body and connected to the substrate through a second elastic body extending in a direction perpendicular to the elastic body, the movable frame having the conductive coil.

And a second elastic member disposed between the movable frame and the movable structure and connected to the movable structure via the elastic body and connected to the movable frame through a third elastic body extending in the same direction as the extending direction of the elastic body, And a second movable frame mounted thereon.

And a reinforcing frame disposed between the second movable frame and the movable structure and connected to the movable structure via the elastic body and connected to the second movable frame through a fourth elastic body.

The upper surface of the movable structure may be a reflective surface for reflecting light.

According to the present invention, a magnet portion is disposed at a lower portion of a movable portion constituted by a movable structure and a conductive coil, and magnetic poles that are opposite to each other in a direction perpendicular to a reference line obliquely intersecting the rotation axis of the movable structure as viewed in plan view, And at least one pair of stimulus is present in each of them. Thus, the intensity of the magnetic field acting on the conductive coil can be increased to a considerable extent.

1 is a perspective view schematically showing a conventional scanning micromirror;
2 is a perspective view schematically showing a scanning micromirror according to an embodiment of the present invention.
Figs. 3 to 5 schematically show various examples of the magnet arrangement structure of the magnet portion according to the embodiment of the present invention; Fig.
Figs. 6 to 8 are views schematically showing other examples of the movable portion according to the embodiment of the present invention. Fig.
9 is a view showing a waveform of a driving current applied to the conductive coil for two-axis driving of the scanning micro-mirror of FIG. 6;

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Hereinafter, for convenience of explanation, a scanning micromirror will be described as an electromagnetic force actuating actuator.

2 is a perspective view schematically showing a scanning micromirror according to an embodiment of the present invention.

2, the micromirror 100 according to the embodiment of the present invention includes a magnetic field generating unit 300 for forming a magnetic field, and a magnetic field generating unit 300 for forming an electric field that interacts with a magnetic field formed in the magnetic field generating unit 300, And a movable unit 200 that performs micro-scanning driving using Lorentz force generated due to the driving force.

The movable part 200 may include a substrate 210, a movable structure 220, and an elastic body 230.

An open area OS is formed in the substrate 210 and a movable structure 220 is located in the open area OS.

The movable structure 220 functions as a mirror plate. The upper surface of the movable structure 220 is formed as a reflecting surface and can reflect incident light.

The movable structure 220 may be configured to have a polygonal shape or a circular shape of a triangle or more in plan view. On the other hand, in the embodiment of the present invention, for convenience of explanation, a case of having a quadrangular shape is taken as an example.

The movable structure 220 may be connected to and supported by the substrate 210 through the elastic body 230. The elastic body 230 is configured to function as a torsion bar and can be connected to opposite ends of the movable structure 220 to function as a rotation axis RA of the movable structure 220.

The movable structure 220 may include a conductive coil 240 having the same planar shape as the movable structure 220 and having a driving current flowing along the periphery thereof. The conductive coil 240 may be formed on the upper surface which is a reflective surface. On the other hand, as another example, the conductive coil 240 may be formed on the rear surface opposite to the upper surface.

The conductive coil 240 may extend to the substrate 210 along the elastic body 230 connected to one side of the movable structure 220. That is, the conductive coil 240 is drawn into the movable structure 220 from the substrate 210 via the elastic body 230 and thereafter is turned one direction along the periphery of the movable structure 220 to be drawn out to the elastic body 230 And then return to the substrate 210.

Accordingly, the driving current is turned in a loop in one clockwise or counterclockwise direction and output to the same side as the input side.

When a driving current flows through the conductive coil 240, a Lorentz force acts on the conductive coil 240 due to the magnetic field generated from the magnetic field generating unit 300. Accordingly, the extending direction of the elastic body 230 is The movable structure 220 can be rotated at a predetermined angle using the rotation axis RA.

The magnetic field generating unit 300 generating a magnetic field as described above may include a lower pole piece 310 and a magnet unit 320 on the pole piece 310.

The pole piece 310 is made of a material having high magnetic permeability, so that the strength of the magnetic field generated in the magnet part 320 can be increased.

The magnet part 320 according to the embodiment of the present invention has a magnetic pole which crosses the rotation axis RA at an acute angle with respect to the rotation axis RA and is opposite to the reference line passing through the center of the movable structure 220, As shown in FIG. Particularly, the magnet portion 320 is provided with first and second regions corresponding to the conductive coil 240 and having two magnetic poles opposite to each other on both sides of the reference line, and first and second regions that are symmetrical with respect to the reference line, And third and fourth regions in which stimuli opposite to the region are formed.

The magnet unit 300 having such a magnetic pole arrangement may be configured in various forms using a plurality of magnets, which will be described in more detail with reference to FIGS. 3 to 5. FIG.

3 to 5 are views schematically showing various examples of the magnet arrangement structure of the magnet portion according to the embodiment of the present invention.

In FIGS. 3 to 5, for convenience of explanation, a case where the first to fourth magnets 321 to 324 are formed in each of the first to fourth regions is described as an example of the magnet portion 320.

In such a case, the first to fourth magnets 321 to 324 are configured to be magnetized in a direction perpendicular to the substrate surface. Here, the magnetic poles on the surfaces of the first to fourth magnets 321 to 324 are N poles, S poles, N poles, and S poles, respectively.

3, the first and second magnets 321 and 322 having mutually opposite magnetic poles are positioned symmetrically opposite to each other on both sides of the reference line RL intersecting with the rotation axis RA at an acute angle. Here, it is preferable that the rotation axis RA and the reference line RL are formed to be 45 degrees, but the present invention is not limited thereto.

The third and fourth magnets 323 and 324 are positioned symmetrically with respect to the reference line RL outside the first and second magnets 321 and 322, respectively.

Here, each of the first and second magnets 321 and 322 may be configured so that the direction of the magnetic field generated between the third and fourth magnets 323 and 324 located at the outer side has at least two directions, For example, the first and second magnets 321 and 322 may be formed in a right triangle shape.

In such a case, the third and fourth magnets 323 and 324 may be formed so as to surround the outside of the first and second magnets 321 and 322.

On the other hand, the conductive coil 240 can be configured to correspond to the first and second magnets 321 and 322. In this regard, it is preferable that the region surrounded by the conductive coil 240 in plan view is configured to substantially coincide with or completely cover the region where the first and second magnets 321 and 322 are formed, But is not limited to. For example, the region surrounded by the conductive coil 240 may be configured to be smaller than the region where the first and second magnets 321 and 322 are formed

As described above, by constructing the magnet portion 320, the intensity of the magnetic field acting on the conductive coil 240 can be increased to a considerable extent.

That is, by forming the magnet portion 320 in the lower portion of the movable structure 220, the two magnets that generate the magnetic field can be configured to contact each other, so that there is substantially no restriction on the spacing between the magnets It can be said that no.

The first and third magnets 321 and 323 are arranged in parallel to the conductive coil 240 so as to generate a magnetic field acting on the conductive coil 240. In addition, And the second and fourth magnets 322 and 324 function as another pair of poles corresponding to different portions of the conductive coil 240. [

According to the configuration of the magnet unit 320, the intensity of the magnetic field acting on the conductive coil 240 can be increased to a considerable extent as compared with the conventional one.

4, unlike the structure of FIG. 3, the first and second magnets 321 and 322 may be formed in a semicircular shape. In such a case, similarly to FIG. 3, the conductive coil 240 can be configured to correspond to the first and second magnets 321 and 322.

3 and 4, the regions where the first and second magnets 321 and 322 are formed are surrounded by the regions where the third and fourth magnets 323 and 324 are formed, and the first and second magnets 321 and 322 are surrounded by the regions where the third and fourth magnets 323 and 324 are formed, 322 are formed in the shape of a triangle and a semicircle, and the inner sides of the third and fourth magnets 323, 324 are formed along the outer sides of the first and second magnets 321, 322. Meanwhile, the first and second magnets 321 and 322 may be formed in a polygonal shape such as a rectangle in addition to the triangle.

5 and 5, the first and second magnets 321 and 322 extend in both directions along the reference line RL and extend to the side of the magnet portion 320 As shown in FIG.

In such a case, the conductive coil 240 can be configured so as to correspond to the first and second magnets 321 and 322. In particular, the conductive coil 240 may be configured to be positioned within the outermost sides of the first and second magnets 321 and 322, but is not limited thereto.

In the above embodiments, the magnet portion 320 has a rectangular shape in a plan view. Alternatively, the magnet portion 320 may have a polygonal shape such as a pentagon or a circular shape.

In the above description, the movable part 200 of the single-axis scanning structure in which the movable structure 220 is rotated along one rotation axis and scanning is performed has been described as an example.

Meanwhile, the movable unit 200 is configured in a different form from that described above to perform two-axis scanning driving, which will be described with reference to FIGS.

6 to 8 are views schematically showing other examples of the moving part according to the embodiment of the present invention.

6, the movable unit 200 may include a substrate 210, a movable structure 220, a movable frame 250, and first and second elastic members 231 and 232.

As described above, the movable part 200 of FIG. 6 further comprises the movable frame 250 and one elastic body as compared with the movable part of FIG.

The movable frame 250 is configured to surround the outside of the movable structure 220. The movable frame 250 may be connected to and supported by the movable structure 220 through a first elastic body 231 connected to both sides of the movable structure 220. The movable frame 250 may be connected to the substrate 210 through a second elastic body 232 formed on both sides thereof.

The first elastic body 231 extends along the first direction and the movable structure 220 can rotate with the extension direction of the first elastic body 231 as the first rotation axis RA1.

The second elastic body 232 extends along a second direction perpendicular to the first direction and the extension direction of the second elastic body 232 is a second rotation axis RA2, .

As described above, by the rotation of the movable frame 250 about the second rotation axis RA2 and the rotation of the movable structure 220 about the first rotation axis RA1, the two-axis scanning drive can be realized do.

In this regard, the movable frame 250 may be configured in the form of a loop and a conductive coil 240 through which a driving current flows. The conductive coil 240 may be extended to the substrate 210 along the second elastic body 232 connected to one side of the movable frame 250. That is, the conductive coil 240 is drawn into the movable frame 250 from the substrate 210 via the second elastic body 232, and is then turned a second time along the movable frame 250 to be drawn out to the second elastic body 232 And then return to the substrate 210.

When the driving current is applied to the conductive coil 240, the magnetization direction of the magnet portion 320 intersects the first and second rotation axes RA1 and RA2 in the direction opposite to the direction of the reference line RL Can be generated in the conductive coil 240.

Accordingly, by controlling the frequency of the driving current applied to the conductive coil 240, the two-axis scanning driving can be realized.

Here, the driving current applied to the conductive coil 240 for two-axis driving can be configured as shown in Fig. For example, a waveform current having a first frequency f1 of 60 Hz and a waveform current having a second frequency f2 of 20 kHz are simultaneously applied to the first frequency f1 waveform to generate the second frequency f2 So that the drive current to which the waveform is applied can be applied.

In this regard, the movable frame 250 and the movable structure 220 are configured to be driven at different resonance frequencies. For example, the movable structure 220 rotates for horizontal scanning with respect to the first rotation axis RA1 and can be driven at a resonance frequency of about 20 kHz. On the other hand, the movable frame 250 rotates for vertical scanning with respect to the second rotation axis RA2, and can be driven at a resonance frequency of approximately 300 Hz.

In such a case, when the current of the first frequency f1 lower than the resonance frequency of the movable frame 250 is applied as the drive current, the movable frame 250 is forced to be driven in the resonance mode according to the first frequency f1 It is possible to rotate about the second rotation axis RA2.

When the current of the second frequency f2, which is the same as the resonant frequency of the movable structure 220, is applied as the driving current, the movable structure 220 is resonantly driven at the corresponding frequency and rotated about the first rotational axis RA1 .

On the other hand, when the current having the first frequency f1 and the second frequency f2 are simultaneously applied, both the movable frame 250 and the movable structure 220 can rotate around the corresponding rotation axis.

According to the above-described method, the two-axis scanning driving can be realized by using one conductive coil 240. [

7, the movable unit 200 includes a substrate 210, a movable structure 220, first and second movable frames 251 and 252, first to third elastic members 231 to 233, . ≪ / RTI >

As described above, the moving part 200 of Fig. 7 further comprises one movable frame and one elastic body as compared with the moving part of Fig.

The first movable frame 251 is configured to surround the outside of the movable structure 220. The first movable frame 251 may be connected to and support the movable structure 220 through a first elastic body 231 connected to both sides of the movable structure 220. The first movable frame 251 may be connected to and supported by a second movable frame 252 configured to surround the first and second elastic frames 232 and 232 formed on both sides thereof. The second movable frame 252 may be connected to the substrate 210 through a third elastic body 233 formed on both sides thereof.

The first elastic body 231 extends along the first direction and the second elastic body 232 extends along the first direction same as the first elastic body 231. Therefore, the movable structure 220 and the first movable frame 251 can rotate about the first rotation axis RA1 about the first rotation axis RA1.

The third elastic body 233 extends along a second direction perpendicular to the first direction and the extending direction of the second elastic body 232 is defined as a second rotation axis RA2, and the second movable frame 252 is rotated .

By the rotation of the second movable frame 252 about the second rotation axis RA2 and the rotation of the first movable frame and the movable structures 251 and 220 around the first rotation axis RA1, As a result, a two-axis scanning structure can be realized.

In this regard, each of the first and second movable frames 251 and 252 may be constituted by a first and a second conductive coil 241 and 242, which are formed in a loop shape and through which a driving current flows.

When a driving current flows through the conductive coils 241 and 242, Lorentz force acts on the conductive coils 241 and 242 due to the magnetic field generated by the magnetic field generating unit 300.

The second movable frame 252 can be rotated at a predetermined angle about the second rotation axis RA2 which is the extending direction of the third elastic body 233 and thereby connected to the second movable frame 252 The first movable frame and the movable structures 251 and 220 can also rotate along the second rotation axis RA2.

The first movable frame 251 can rotate at a predetermined angle about the first rotation axis RA1 extending in the direction of extension of the second elastic body 233, The structures 251 and 220 can also rotate along the first rotation axis RA1.

As described above, the two-axis scanning structure can be realized by rotating about the first and second rotation axes RA1 and RA2 as described above.

Particularly, since the first movable frame 251 connected to the movable structure 220 through the first elastic body 231 is provided inside the second movable frame 252, the angular displacement of the movable structure 220 can be amplified .

The first movable frame 251 and the movable structure 220 are controlled by controlling the frequency, size, and direction of the driving current flowing through the first conductive coil 241 provided in the first movable frame 251, It is possible to rotate in opposite directions, that is, in the opposite directions, about the first rotation axis RA1. This can be realized by controlling the drive current so that the drive current frequency of the first movable frame 251 coincides with the resonant frequency of the movable structure 220.

8, the movable unit 200 includes a substrate 210, a movable structure 220, first and second movable frames 251 and 252, a reinforcement frame 253, And may include first to fourth elastic bodies 231 to 234.

As described above, the moving part 200 of Fig. 8 further comprises the reinforcing frame 253 and one elastic body as compared with the moving part of Fig.

The reinforcing frame 253 is configured to surround the outer side of the movable structure 220 and is connected to the movable structure 220 through the fourth elastic body 234. The reinforcing frame 253 corresponds to a structure for preventing the dynamic structure 220 from being thermally deformed due to external heat or dynamic deformation due to flapping during flow. The reinforcing frame 253 may move in the same direction and at the same rotation angle as the movable structure 220.

The reinforcing frame 254 is configured to be connected to the first movable frame 251 through the fourth elastic body 254 so that the first movable frame 251 rotates about the first rotation axis RA The reinforcing frame and the movable structures 254 and 220 can rotate together.

As described above, according to the embodiment of the present invention, the magnet portion is disposed at the lower portion of the movable portion constituted by the movable structure and the conductive coil, and the magnet portion is disposed opposite to the direction perpendicular to the reference line obliquely intersecting the rotation axis of the movable structure The stimulation is configured so that at least one pair of stimulus is present on each side of the reference line alternately on the surface. Thus, the intensity of the magnetic field acting on the conductive coil can be increased to a considerable extent.

The embodiment of the present invention described above is an example of the present invention, and variations are possible within the spirit of the present invention. Accordingly, the invention includes modifications of the invention within the scope of the appended claims and equivalents thereof.

100: scanning micro mirror 200: moving part
210: substrate 220: movable structure
230: elastic body 240: conductive coil
300: magnetic field generator 310: pole piece
320: magnet portion

Claims (10)

A moving part including a movable structure which is driven by an extension direction of an elastic body located in an open region of a substrate and which is connected to an outer side of the substrate as a rotation axis and a conductive coil which generates a driving force for the movable structure by interaction of a driving current with a magnetic field;
A magnetic field is generated at a lower portion of the movable portion,
First and second regions having mutually opposite magnetic poles on the upper surface with reference to a reference line intersecting at an acute angle with the rotation axis in plan view and a magnetic pole opposite to the first region outside the first region on the upper surface And a fourth region formed outside the second region and having a magnetic pole opposite to the second region on the upper surface,
And an electromagnetic actuator.
The method according to claim 1,
Wherein each of the first and second regions has a polygonal or semicircular shape,
Wherein the third and fourth regions are configured to surround the first and second regions
Electromagnetically driven actuators.
The method according to claim 1,
Wherein each of the first and second regions is configured to extend to both sides of the magnetic field generating portion along the reference line
Electromagnetically driven actuators.
The method according to claim 1,
The magnetic field generator includes first to fourth magnets corresponding to the first to fourth regions and magnetized in the vertical direction,
Electromagnetically driven actuators.
The method according to claim 1,
Wherein the reference line intersects the rotation axis at an angle of < RTI ID = 0.0 > 45 &
Electromagnetically driven actuators.
The method according to claim 1,
The movable structure is connected to the substrate through the elastic body, and the conductive coil is installed in the movable structure
Electromagnetically driven actuators.
The method according to claim 1,
And a movable frame connected to the substrate through a second elastic body extending in a direction perpendicular to the elastic body and connected to the movable structure through the elastic body,
Electromagnetically driven actuators.
8. The method of claim 7,
And a second elastic member disposed between the movable frame and the movable structure and connected to the movable structure via the elastic body and connected to the movable frame through a third elastic body extending in the same direction as the extending direction of the elastic body, Comprising a second movable frame
Electromagnetically driven actuators.
9. The method of claim 8,
A reinforcing frame disposed between the second movable frame and the movable structure and connected to the movable structure via the elastic body and connected to the second movable frame via a fourth elastic body;
Electromagnetically driven actuators.
The method according to claim 1,
Wherein the upper surface of the movable structure is composed of a reflecting surface for reflecting light
Electromagnetically driven actuators.

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