KR101191535B1 - Scanning micromirror - Google Patents

Abstract

The present invention relates to a scanning micromirror. According to the present invention, the angle of rotation of the mirror plate can be adjusted more accurately by measuring the rotation angle of the mirror plate. According to the present invention, the mirror plate can be driven about two axes, and the rotation angle of the mirror plate can be increased.

Scanning micromirrors, piezoresistors, Wheatstone bridge

Description

Scanning micromirror

The present invention relates to a scanning micromirror.

Along with the development of optical device technology, various technologies using optical as an input / output terminal and information transfer medium of various information are emerging. Such technologies include scanning and using beams from a light source such as a barcode scanner or a basic scanning laser display.

In particular, recently, a system using a high spatial resolution beam scanning has been developed. Such a system includes a projection display system having excellent high resolution of primary colors using laser scanning, a head mounted display (HMD), and a laser. Printers and the like.

This beam scanning technique requires a scanning micromirror with various scanning speeds and scanning ranges, that is, angular displacement and tilting angle, depending on the application. Conventional beam scanning requires a galvanic mirror. It is implemented by adjusting the angle of incidence between the reflection surface and the incident light of the driven mirror, such as a galvanic mirror or a rotating polygon mirror.

Scanning micromirrors that implement beam scanning as described above have been disclosed in "Scanning micromirror" of Patent Publication No. 10-2007-0121082.

However, the conventional scanning micromirror does not measure the rotation angle of the mirror, there is a problem that can not control the angular displacement of the mirror more precisely.

An object of the present invention is to provide a scanning micromirror having a sensor unit capable of measuring the rotation angle of the mirror plate or gamble.

An object of the present invention is to provide a scanning micromirror having a plurality of gimbals, which amplifies the rotation angle of the biaxial drive and the mirror plate.

According to one embodiment of the invention, the mirror plate for reflecting light; A gimbal provided around the mirror plate to support the mirror plate through a first elastic body; A support for supporting the gamble through a second elastic body; A winding through which current is provided in at least one of the gamble and the mirror plate; Magnetic material forming a magnetic field around the winding; A control unit for controlling a current flowing through the winding so that the mirror plate rotates the first elastic body about the axis and the gimbal rotates the second elastic body about the axis; And a sensor unit provided at the first elastic body and the second elastic body to measure rotation angles of the mirror plate and the gamble.

According to another embodiment of the present invention, a mirror plate for reflecting light; An inner gamble provided around the mirror plate to support the mirror plate through a third elastic body; An outer gamble provided around the inner gamble and supporting the inner gamble through a fourth elastic body; A support for supporting the outer gamble through a fifth elastic body; Windings provided in the inner and outer gambles, through which current flows; Magnetic material forming a magnetic field around the winding; And a controller configured to control a current flowing through the winding so that the mirror plate and the inner gamble rotate in the opposite phase with respect to the third elastic body, and the outer gamble rotates the fifth elastic body with the axis. do.

According to the present invention, the angle of rotation of the mirror plate can be adjusted more accurately by measuring the rotation angle of the mirror plate.

According to the present invention, the mirror plate can be driven about two axes, and the rotation angle of the mirror plate can be increased.

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

1 is a perspective view of a scanning micromirror 10 according to an embodiment of the present invention.

As shown in FIG. 1, the scanning micromirror 10 according to the exemplary embodiment of the present invention is provided in the vicinity of the mirror plate 11 and the mirror plate 11 for reflecting light, and thus, the first elastic body 12. Gimbal (13) for supporting the mirror plate 11 through the support portion 15, the gimbal (13) and the mirror plate (13) for supporting the gimbal (13) through the second elastic body (14) 11) a winding (not shown) provided in at least one of the current flow, a magnetic material (not shown) forming a magnetic field around the winding, and controlling the current flowing in the winding, the mirror plate is the first elastic body 12 Is rotated about the axis, the control unit (not shown) for driving the gimbal 13 to rotate the second elastic body 14 to the axis, and the first elastic body 12 and the second elastic body 14 is provided And a sensor unit (not shown) for measuring rotation angles of the mirror plate and the gamble.

The mirror plate 11 reflects light emitted from the light source. The mirror plate 11 is supported by a gamble 13 provided around the mirror plate 11. That is, the gamble 13 is provided around the mirror plate, and is connected to the mirror plate 11 through a first elastic body 12, and the mirror plate 11 through the first elastic body 12. Support.

As a result, the gamble 13 may support the rotation of the mirror plate 11 when the mirror plate 11 is twisted about the first elastic body 12, that is, when the mirror plate 11 rotates.

According to an embodiment, the mirror plate 11 and the gamble 13 may be configured in various forms of circular, elliptical, square or polygonal.

The support part 15 supports the gamble 13 through the second elastic body 14. That is, the support part 15 is connected to the outer side of the gimbal 13 by the second elastic body 14, and when the gimbal 13 twists the second elastic body 14 in an axis, that is, rotates. If it can support the rotation of the gamble (13).

The winding (not shown) is provided in at least one of the gamble 13 and the mirror plate 11 to flow a current.

For example, referring to FIG. 1, the winding is provided on one side of the gimbal 13 through one side second elastic body 14a from one side support part 15a and through the other side second elastic body 14b. It can be distributed up to the other side support portion 15b.

According to an embodiment, the winding may also be provided on the first elastic body 12 and the mirror plate 11.

According to an embodiment, an insulating layer may be formed below the winding to electrically insulate the gimbles 13, the mirror plate 11, the first elastic body 12, and the second elastic body 14 on which the windings are formed.

The magnetic material (not shown) forms a magnetic field around the winding. According to an embodiment, the magnetic material may be provided under the scanning micromirror 10 illustrated in FIG. 1 to form a magnetic field over the entire scanning micromirror 10.

The control unit (not shown) controls the current flowing in the windings, so that the mirror plate 11 rotates the first elastic body 12 about its axis, and the gimbal 13 controls the second elastic body 14. Drive to rotate on the shaft.

That is, the controller controls the frequency, direction, magnitude, and the like of the current flowing through the winding to drive the mirror plate 11 and the gimbal 13 to rotate the first and second elastic bodies about the axis.

The mirror plate 11 or the gamble 13 may rotate the first and second elastic bodies by the external force by the interaction between the current flowing through the windings provided in the mirror plate and the gamble and the magnetic field formed by the magnetic body. Can be.

For example, when a current having a predetermined frequency flows through a winding formed in the gamble 13, the current interacts with a magnetic field to generate an electromagnetic force, and the gamble 13 uses the generated electromagnetic force as a driving force to generate the second force. The elastic body 14 can be rotated about an axis.

On the contrary, when a current of a predetermined frequency flows through a winding formed in the mirror plate 11, the current interacts with a magnetic field to generate an electromagnetic force, and the gamble 13 uses the generated electromagnetic force as a driving force to form the first elastic body ( 12) can be rotated about the axis.

The sensor unit (not shown) is provided on at least one of the first elastic body 12 and the second elastic body 14 to measure the rotation angles of the mirror plate 11 and the gamble 13.

According to an embodiment of the present invention, the sensor unit may be a piezoresistor whose resistance value changes as the first and second elastic bodies twist.

2 is an enlarged view of a sensor unit according to an exemplary embodiment of the present invention.

As shown in FIG. 2, the sensor unit 16 according to the exemplary embodiment of the present invention is provided at both ends of the piezoresistor 161 and the piezoresistor 161 whose resistance value changes as the elastic body 14a is twisted. The ohmic contact node 162 may include a conductive wire 163 connected to the ohmic contact node 162.

The elastic body may be the first elastic body 12 or the second elastic body 14 of FIG. 1. That is, the elastic body may be an axis connected to the mirror plate 11 or the gamble 13 to support a rotational motion.

According to an embodiment, the elastic body 14a may be formed of silicon.

According to an embodiment, the sensor unit 16 may be formed on or in the surface of the elastic body. Preferably, the sensor unit 16 may be formed on the upper surface of the elastic body, but is not limited thereto and may be formed on the side or the lower surface of the elastic body.

The sensor unit 16 may include a piezoresistor 161 whose resistance value changes as the elastic body 14a is twisted.

According to an embodiment of the present invention, when the elastic body 14a is formed of silicon, and the silicon is n-type silicon, the piezoresistor 161 is arranged in parallel to 110 in the crystal direction of the silicon. Can be.

That is, as shown in FIG. 2, the piezoresistor 161 may be arranged in parallel with 110 in the silicon crystal direction displayed on the upper right.

This is to allow the piezoresistor 161 to be arranged in a direction in which the piezoresistance coefficient due to torsion or torsion of silicon is maximized. To this end, when the silicon constituting the elastic body is n-type, the piezoresistor 161 is arranged in parallel to the crystal direction 110, so that the elastic body 14a is the axis 141 to the axis When twisted, the change in resistance value is maximized.

As illustrated in FIG. 2, the piezoresistor 161 may be provided on the central axis of the elastic body 14a. However, the piezoresistive body 161 may be provided at any point on one surface of the elastic body 14a.

When the elastic body 14a is made of p-type silicon, the piezoresistor 161 may be formed by doping n-type impurities to the elastic body 14a. In this case, the impurity is phosphorus. , Arsenic, antimony and the like.

On the contrary, when the elastic body 14a is made of n-type silicon, the piezoresistor 161 may be formed by doping the elastic body 14a with p-type impurities, and the impurities may be boron. have.

Ion implantation or diffusion may be used as a method of doping the impurity.

In order to easily detect the change in the resistance value of the piezoresistor 161, the resistance portion of the piezoresistor 161 is configured to be larger than the resistance of other portions. For example, the length of the conductive wire 163 may be reduced, and the width thereof may be increased to reduce the resistance of the conductive wires connected in series, and the resistance of the piezoresistor 161 may be relatively large.

In the piezoresistor 161 formed on the peeling of the silicon substrate, the resistance value changes when a stress is applied, and a resistance sensitivity relation that indicates the degree of change in the resistance value is as follows.

Here, sigma _l and sigma _t represent stress components parallel to and perpendicular to the current direction, respectively, and π _l and π _t represent piezoelectric resistance coefficients and vertical piezoelectric resistance coefficients parallel to the current direction, respectively.

According to Equation 1, in order to maximize resistance sensitivity, σ _l , σ _t and π _l , π _t must be made large.

According to the exemplary embodiment of the present invention, when the piezoresistor 161 forms an angle of 45 ° with the rotation axis of the elastic body 14a, π _l and π _t may be maximized to maximize resistance sensitivity.

In addition, according to the exemplary embodiment of the present invention, when the piezoresistor 161 is positioned at the central point of the long axis of the elastic body 14a, σ _l and σ _t are maximized, thereby maximizing resistance sensitivity.

However, when the elastic body 14a is located at the central point of the long axis, the length of the conductive wire 53 is increased so that the resistance value of the conductive wire 53 is increased, so that the resistance sensitivity of the piezo resistor 161 and the conductive wire 53 are increased. A trade-off of the resistance value is needed.

When the piezoresistor 161 is located at the central point of the long axis of the elastic body 14a, the rotation angle with respect to the torque T and the maximum shear stress τ _max are as follows.

Where L is the major axis length of the elastic body 14a, a is the major axis length of the cross section of the elastic body 14a, b is the minor axis length of the cross section of the elastic body 14a, G is the shear stress coefficient of silicon, c1, c2 is a is a function for, b. That is, the maximum shear stress τ _max is proportional to the driving angle, and the resistance sensitivity is proportional to the driving angle as follows.

According to Equation 4, when π _l -π _t is the maximum, it can be seen that the resistance sensitivity of the piezoresistor 161 is maximum.

The piezoresistive coefficient depends on the silicon crystal direction, and according to one embodiment of the present invention, when the elastic body 14a is made of n-type silicon, the piezoresistor 164 is formed in the crystal direction of silicon (110). May be arranged parallel to

On the contrary, according to another embodiment of the present invention, when the silicon constituting the elastic body 14a is p-type, the piezoresistor 161 may be arranged parallel to (100) in the crystal direction of the silicon. .

As described above, when the piezoresistors 161 are arranged along the silicon crystal direction, π _l and π _t have different signs, and π _l -π _t may be the maximum.

The π _l -π _t is a function of the doping concentration and the temperature, and when the doping concentration is 10 ¹⁸ cm ³ or less, π _l , π _t decreases by 0.25% when the temperature increases by 1 ° C.

π _l = -102.2 * 10 ^-11 Pa ^-1 , π _t = 53.4 * 10 ^-11 Pa ^-1 at room temperature for n-type impurities and π _l = 72 * 10 ^-11 at room temperature for p-type impurities Pa ^-1 , π _t = -66 * 10 ^-11 Pa ^-1 .

As shown in FIG. 2, when the elastic body 14a is made of p-type silicon, the piezoresistor 161 is aligned in parallel to the (110) direction, and the elastic body 14a is in the (110) direction. Can be arranged.

In this case, since the (110) direction coincides with the mask direction during KOH etching, there is an advantage that the KOH etching process may be applied together when manufacturing the elastic body 14a.

In addition, when the elastic body 14a is made of p-type silicon, the elastic body 14a is also in terms of resistance sensitivity because π _l -π _{t, which} is a difference in piezoelectricity coefficient, is larger than that of n-type silicon. Is composed of p-type silicon, and the piezoresistor is composed of n-type impurities.

3 is an enlarged view of a sensor unit according to another exemplary embodiment of the present invention.

As shown in FIG. 3, when the elastic body 14a is made of n-type silicon, the piezoresistor 164 may be arranged parallel to 110 in the crystal direction of silicon.

Unlike the piezoresistor 161 of FIG. 2 arranged toward the upper right, the piezoresistors 164 of FIG. 3 are arranged towards the upper left, but both of these piezoresistors 161 and 164 are both parallel to the crystal direction 110. It is common in that it is arranged.

According to another embodiment of the present invention, when the silicon constituting the elastic body 14a is a p-type, the piezoresistor 161 may be arranged parallel to (100) in the crystal direction of the silicon.

This is also to ensure that the piezoresistor 161 is arranged in a direction in which the piezoelectric resistance coefficient of silicon is maximized when the elastic body 14a composed of p-type silicon is twisted about the central axis 141.

To this end, unlike the n-type silicon, when forming the sensor unit 16 in an elastic body made of p-type silicon, the piezoresistor 161 may be arranged to be parallel to the silicon crystal direction (100).

In some embodiments, the piezoresistor 161 may be arranged such that an angle between the central axes 141 where the elastic body 14a is twisted is 45 °. That is, as shown in FIGS. 2 and 3, the piezoresistive body may be arranged such that an angle between the piezoelectric body and the central axis 141 of the elastic body 14a is 45 °.

The piezoresistor 161 may receive a current through the conductive wire 163. According to an embodiment, the controller (not shown) supplies a constant current to the piezo resistor 161 through the conductive wire 163, and measures the potential difference between both ends of the piezo resistor 161 to measure the piezo resistor ( The change in the resistance value of 161 can be grasped.

By using the change in the measured resistance value, it is possible to calculate the degree of torsion, that is, the torsion angle of the elastic body 14a, and obtain the rotation angle of the gamble 13 or the mirror plate 11 through the torsion angle. have.

In some embodiments, an ohmic contact portion 162 may be provided between the piezoresistive member 161 and the conductive wire 163 to reduce a contact resistance value.

4 is an enlarged view of a sensor unit according to another exemplary embodiment of the present invention.

As illustrated in FIG. 4, the sensor unit 17 may include four piezoresistors 171, 172, 173, and 174, and the four piezoresistors 171, 172, 173, and 174 may constitute a Wheatstone bridge.

That is, each of the four piezoresistors 171, 172, 173, 174 may be arranged to form each side of the rhombus.

Hereinafter, the four piezoresistors 171, 172, 173, and 174 will be described as R1 (171), R2 (172), R3 (173), and R4 (174).

According to an embodiment of the present invention, one diagonal line of the wheatstone bridge constituting the sensor unit 16, that is, a rhombus composed of R1 171, R2 172, R3 173, and R4 174 may be formed. It may be provided to overlap with the central axis 141 of the elastic body (14a).

That is, as shown in FIG. 4, a diagonal line connecting the node N1 175 and the node N2 177 of the Wheatstone bridge may be arranged to overlap the central axis 141 of the elastic body. As a result, the Wheatstone bridge may be arranged on the central axis of the elastic body.

The conductive wire 179 is connected to each node of the Wheatstone bridge.

According to an embodiment of the present invention, the controller (not shown) applies a predetermined voltage to two nodes 175 and 177 of the Wheatstone bridge, that is, nodes N1 and N3, located on the central axis 141 of the elastic body. The degree of twist of the elastic body may be measured by measuring the potential difference between the remaining two nodes 178 and 176.

Specifically, the Wheatstone bridge constituting the sensor unit 16 in the state that the elastic body 14a is not twisted is configured such that the product of the diagonal resistances is the same. That is, it is comprised so that R1-R3 = R2-R4.

Then, a predetermined voltage Vdd is applied between the nodes N1 175 and N2 177 of the Wheatstone bridge. In this case, the potential difference between the other nodes N2 176 and N4 178 of the Wheatstone bridge becomes zero.

Then, when the elastic body 14a is twisted by a predetermined angle with respect to the central axis 141, the resistance values of the piezoresistive elements 171, 172, 173, and 174 constituting the Wheatstone bridge change according to the degree of twisting. In this case, the potential difference between the nodes N2 176 and N4 178 of the Wheatstone bridge is no longer zero, and may have a predetermined potential value.

The controller (not shown) may measure a potential value between the node N2 176 and N4 178 and calculate a degree of twist of the elastic body 14a according to the magnitude of the measured potential value. For example, the greater the measured dislocation value, the greater the degree of twisting of the elastic body 14a, that is, the twisting angle.

In addition, since the angle of rotation of the mirror plate 11 or the gamble 13 increases as the torsion angle of the elastic body 14a increases, the mirror plate 11 or the gamble 13 using the measured torsion angle. You can get a rotation angle of).

5 is a conceptual diagram of a Wheatstone bridge configured by a sensor unit according to another exemplary embodiment of the present invention.

As shown in FIG. 5, the sensor unit 17 according to another embodiment of the present invention includes a Wheatstone bridge including four piezores R1 171, R2 172, R3 173, and R4 174. It may include.

In addition, before the elastic body 14a is twisted, the product of two diagonal resistances of the Wheatstone bridge may be configured to be the same. (Ie R1? R3 = R2? R4)

Then, a predetermined voltage Vdd is applied between two nodes N1 and N3 of the Wheatstone bridge, and the potential value Vout between the other two nodes N4 and N2 is measured.

The potential value between two nodes N4 and N2 is zero before the elastic body 14a is twisted.

In this case, Vout according to the resistance change of R1 to R4 is as follows.

이 되며, 다음과 같은 관계식이 성립될 수 있다. Here, suppose that the piezoresistors R1 to R4 have the same resistance value R,

The following relation can be established.

When the elastic body 14a is twisted, the resistance values of the four piezoresistors constituting the Wheatstone bridge change, and as a result, the potential value between the nodes N4 and N2 is no longer measured as zero.

The controller (not shown) calculates a torsion angle of the elastic body 14a using the measured electric potential value, and uses the calculated torsion angle to mirror the mirror plate 11 or the gimbal 13. You can get a rotation angle of).

Therefore, according to the exemplary embodiment of the present invention, the larger the size of Vout is, the larger the change in the resistance value of the piezoresistor is. As a result, it may be determined that the rotation angle of the elastic body 14a is increased.

As shown in FIG. 4, when the piezoresistor is disposed, not only the resistance sensitivity but also the influence of other deformations except the torsion is eliminated even when the axial bending of the spring occurs, and only the central axis ( 141) there is an advantage of detecting only torsion.

According to one embodiment of the invention, the sensor unit may be provided at the ends of the first elastic body and the second elastic body. According to an exemplary embodiment, the sensor part may be provided at the end of the gimbal 13 of both ends of the first elastic body, and may be provided at the end of the support part 15 of both ends of the second elastic body.

Referring to FIG. 1, when the sensor unit is provided in the first elastic body 12, the sensor part may be disposed at an end portion 22 of the gimbal 13 of both ends of the first elastic body 12. In addition, when the sensor part is provided in the second elastic body 14, the sensor part may be provided at the end portion 21 of the support part 15 of both ends of the second elastic body 14.

In this case, the length of the conductive wire 163 connected to the piezo resistor 161 of the sensor unit 16 becomes short, so that the resistance of the conductive wire 163 decreases, and thus the resistance value of the piezo resistor 161 is reduced. Change can be measured more clearly.

In other words, since the change in the resistance value of the piezoresistor 161 is very small, the larger the resistance of the wire connected in series with the piezoresistor 161, the more difficult it is to detect the change in the resistance value.

Accordingly, the sensor portion 16 is disposed at the end portion 22 of the gamble 13 side of both ends of the first elastic body 12, and the end portion of the support portion 15 of both ends of the second elastic body 14. If it arrange | positions to (21), the length of a conducting wire becomes short and it is possible to measure the change of the resistance value of the piezoresistor 161 more clearly.

6A is a perspective view of a scanning micromirror in accordance with another embodiment of the present invention.

As shown in FIG. 6A, a scanning micromirror 50 according to another embodiment of the present invention is provided around a mirror plate 51 reflecting light and the mirror plate 51, and a third elastic body 52. The outer gamble 53 is provided around the inner gamble 53 and the inner gamble 53 to support the mirror plate 51, and the outer gamble 53 supports the inner gamble 53 through a fourth elastic body 54. 55), a winding (not shown) provided in the support 57 for supporting the outer gamble 55 through the fifth elastic body 56, the inner gamble 53, and the outer gamble 55, through which a current flows, A magnetic body (not shown) that forms a magnetic field around a winding, and a current flowing through the winding, are controlled so that the mirror plate 51 and the inner gamble 53 are in antiphase with each other about the third elastic body 52. And a controller (not shown) for rotating and driving the outer gimbal 55 to rotate the fifth elastic body about its axis.

Unlike the scanning micromirror 10 according to the exemplary embodiment of the present invention illustrated in FIG. 1, the scanning micromirror 50 according to another exemplary embodiment of the present invention illustrated in FIG. 6 may include at least two gimbals. have.

Referring to FIG. 6A, the scanning micromirror 50 according to another embodiment of the present invention includes an inner gamble 53 and an outer gamble 55, and the inner gamble 53 is the third elastic body 52. The mirror plate 51 may be supported therethrough, and the outer gamble 55 may support the inner gamble 53 through a fourth elastic body 54. The outer gamble 55 may be supported by the support part 57 through the fifth elastic body 56.

In some embodiments, the third elastic body 52 and the fourth elastic body 54 are positioned in a straight line, and the fifth elastic body 56 is perpendicular to the third elastic body 52 and the fourth elastic body 54. It can be arranged to achieve.

According to an embodiment, the elastic modulus of the third elastic body 56 and the fourth elastic body 54 may be different from each other. That is, the elastic modulus of the elastic body connecting the mirror plate 51 and the inner gamble 53 and the elastic body connecting the inner gamble 53 and the outer gamble 55 may be different from each other.

According to an embodiment, the elastic body may be configured in any one form of cantilever, torsion beam, and meander.

The mirror plate 51 may be a flat structure having a uniform thickness, but is not limited thereto, and may be a structure having a locally different thickness.

One side of the mirror plate 51 is formed with a reflective surface composed of a metal, a dielectric, and a stack of metal and a dielectric.

The mirror plate 51 may further include a reinforcement frame surrounding the mirror plate 51 to support the mirror plate 51 at a plurality of points, thereby suppressing dynamic deformation of the mirror plate 51. .

6F is a plan view illustrating a mirror plate including the reinforcing frame according to an embodiment of the present invention.

As shown in FIG. 6F, the reinforcement frame 511 surrounds the periphery of the mirror plate 51 and supports the mirror plate 51 at a plurality of points, for example, four points, to support the mirror plate 51. Dynamic deformation can be suppressed.

The winding is provided in the inner gamble 53 and the outer gamble 55 to flow a current. That is, the winding is formed on one surface of the outer gambler 55 and the inner gambler 53 through the fifth elastic body 56, starting from the support part 57, and opposite the supporting part via the opposing fifth elastic body 56. Up to 57 can be formed.

6B-6E are conceptual and plan views illustrating the arrangement of windings in accordance with one embodiment of the present invention.

As shown in FIG. 6B, the scanning micromirror 10 according to the exemplary embodiment of the present invention includes a magnetic body 61 that radially forms a magnetic field, and an outer gamble 55 having a first axis as a rotation axis by interacting with the magnetic field. It may include a first winding (62) for passing a current to rotate the second winding (63) for passing the current to rotate the inner gamble (53) around the axis of rotation with a second axis.

Although the inner gamble 53 and the outer gamble 55 are not shown in FIG. 6B, the first winding 62 is not limited to the outer gamble 55, and any one of the outer gamble 55 and the inner gamble 53 is not shown. It may be formed in one gamble, and the second winding 63 may be formed in a gamble different from the gamble in which the first winding 62 is formed.

As shown in FIG. 6B, the first winding 62 starts at the one support 57, branches through the fifth elastic body 56 into two windings, and two on the outer gimbal 55. It is formed to draw a semi-circle, it can be merged into one winding at the point connected to the fifth elastic body 56 and terminated at the other support 57.

In addition, the second winding 63 starts at one side of the fourth elastic body 54, is branched into two windings, and is formed to draw two semicircles on the inner gimbal 53, and thus the fourth elastic body ( It can be formed to be joined to one winding at the point connected to 54 to terminate at the fourth elastic body 54.

When a current of 2 I is applied to the first winding 62 and the second winding 63, respectively, the first winding 62 and the second winding 63 on the outer gimbal 55 and the inner gimbal 53. Is a current of I, and the current I flowing through the winding may generate an electromagnetic force acting on the winding through interaction with a radial magnetic field formed by the magnetic material 61.

As a result, the outer gamble 55 and the inner gamble 53 may act as the torques T1 and T2 by the generated electromagnetic force to perform a rotational movement with the first and second axes as rotation axes, respectively.

6C is an exemplary diagram showing an arrangement of windings according to another embodiment of the present invention.

Unlike FIG. 6B, which consists of two windings, the winding of FIG. 6C consists of a third winding 64 that is one winding.

As shown in FIG. 6C, the third winding 64 starts on one side of the support 57, passes through a fifth elastic body 56, and forms a quadrant on the outer gamble 55. Then, through the fourth elastic body 54, branched into two windings at points connected with the inner gimbal 53 to form two semicircles on the inner gimbal 53, and again the fourth elastic body 54 At the point where it connects with, it merges into one winding. Then, another quadrant may be formed on the outer gimbal 55 through the fourth elastic body 54, and may be terminated on the other side of the support part 57 via the fifth elastic body 56.

FIG. 6D is a top view of the scanning micromirror with the third winding 64 of FIG. 6C formed.

As shown in FIG. 6D, when a current 2I is applied to one side of the support part 57, a current 2I flows in a quadrant formed on the outer gamble 55, and two windings pass through the fourth elastic body 54. Because of the branching, the current I flows through each winding formed in the inner gimbal 53.

A current of 2I flows clockwise in the second quadrant of the outer gimbal 55, and a current of I flows in the second quadrant of the inner gimbal 53 counterclockwise, so that the scanning micromirror 10 The second quadrant of) is subjected to the same electromagnetic force that the current of I flows clockwise.

Similarly, a current of I flows clockwise in the fourth quadrant of the inner gimbal 53, and a current of 2I flows counterclockwise in the fourth quadrant of the outer gimbal 55, resulting in the scanning micromirror. The fourth quadrant of (10) is subjected to the same electromagnetic force that the current of I flows counterclockwise.

As shown in FIG. 6B, the scanning micromirror having two windings may implement two-axis driving by controlling the driving current applied to each winding. The scanning micromirror having one winding may be configured as shown in FIGS. 6C and 6D. Two-axis driving can be realized by differently applying the frequency of the driving current.

6E is a plan view illustrating an arrangement of a winding according to another embodiment of the present invention.

Unlike the winding of FIG. 6D, in which one winding branches into two windings and merges back into one, the winding of FIG. 6E consists of a fourth winding 65 and a fifth winding 66.

As shown in FIG. 6E, the fourth winding 65 and the fifth winding 66 start on one side of the support 57, pass through the fifth elastic body 56, and form a quadrant on the outer gimbal 55. do. Then, via a fourth elastic body 54, the fourth winding 65 forms one semicircle on the inner gimbal 53, and the fifth winding 66 is the other on the inner gimbal 53. Form a semicircle.

The fourth and fifth windings 65 and 66 again form another quadrant on the outer gimbal 55 via the fourth elastic body 54 and terminate on the other side of the support 57 via the fifth elastic body 56. .

The scanning micromirror having the winding as shown in FIG. 6E may implement two-axis driving by differently applying the frequency of the driving current.

The windings shown in FIGS. 6B-6E may be formed of one or more metal layers.

In some embodiments, the winding may be made of a metal such as Ti, Cr, Cu, Au, Ag, Ni, Al, or ITO (Indume Tin Oxide), a conductive polymer, or a combination thereof.

The controller may control the current flowing through the winding to drive the mirror plate 51 and the inner gimbal 53 to rotate the third elastic body 52 in an opposite phase with respect to the axis.

As described above, the magnetic body 61 may generate an electromagnetic force in the winding when a driving current flows in the winding by forming a radial magnetic field around the winding.

According to an embodiment, the magnetic material 61 may be a columnar permanent magnet having a predetermined cross-sectional shape.

Preferably, as shown in Figure 6b, the magnetic material 61 is a columnar inner magnet 611 having a predetermined cross-sectional shape, a donut-shaped outer magnet 612 surrounding the inner magnet 611 and the It may include an inner magnet 611 and a support 613 for supporting the outer magnet 612.

The cross section of the inner magnet and the outer magnet may be a circle, an ellipse or a polygon.

The support 613 may be made of a ferromagnetic material such as iron and ferrite having a high permeability.

The inner magnet 611 and the outer magnet 612 may have the same thickness, the diameter of the support 613 may match the diameter of the outer magnet 612.

According to an embodiment, in order to maximize the strength of the radially formed magnetic field, the inner magnet 611 and the outer magnet 612 may be magnetized in opposite directions, respectively.

As described above, when a current I flows in each of the windings, the windings interact with the magnetic field and are subjected to the Lorentz force in the vertical direction, whereby the following torque T is applied.

&Quot; (6) "

Where r1 is the radius of the winding, μ is the permeability of air and H _r is the intensity of the radial magnetic field.

7 to 10 are exemplary views showing the driving of the scanning micromirror 50 according to another embodiment of the present invention.

As shown in FIG. 7, the outer gamble 55 of the scanning micromirror 50 according to another embodiment of the present invention may be driven to rotate the fifth elastic body 56.

That is, the control unit flows a current through the winding formed in the outer gamble 55, and the outer gamble 55 is the fifth by using the electromagnetic force generated by the interaction of the current flowing in the winding and the surrounding magnetic field as an external force. The elastic body 56 can be driven to rotate about an axis.

As a result, the mirror plate 51 of the scanning micromirror 50 can be uniaxially driven with the third and fourth elastic bodies as the axis and biaxially driven with the fifth elastic body as the axis. In addition, the scanning micromirror 50 according to another embodiment of the present invention does not rotate the mirror plate 51 directly, but rotates the inner gimbals 53 located at the periphery so that the mirror plate 51 is driven by resonance. In addition, the rotation angle of the mirror plate 51 may be increased.

In some embodiments, the scanning micromirror may rotate the mirror plate 51 and the inner gimbal 53 in opposite directions with respect to the third elastic body 52.

That is, as shown in Figure 8, the control unit (not shown) controls the frequency, magnitude, direction, etc. of the current flowing through the winding (not shown), so that the mirror plate 51 and the inner gamble 53 is The third elastic bodies 52 can be driven to rotate in an opposite phase with respect to the axis.

For example, the mirror plate 51 rotates the third elastic body 52 in the counterclockwise direction, and the inner gimbal 53 rotates the third elastic body 52 in the clockwise direction. Can be driven.

According to an embodiment of the present invention, the winding is not formed on the mirror plate 51, but may be formed only on the inner gamble 53 and the outer gamble 55. The controller does not directly drive the mirror plate 51 to rotate the mirror plate 51, but rotates the inner gamble 53 connected through the third elastic body 52 so that the mirror plate ( 51) can be rotated.

That is, the controller drives the inner gamble 53 to rotate by flowing a current through the winding formed on the inner gamble 53. In this case, the controller may control the current so that the driving frequency of the inner gamble 53 matches the resonance frequency of the mirror plate 51.

As a result, the mirror plate 51 rotates in the opposite direction to the rotational direction of the inner gimbal 53, that is, is driven in reverse phase, and the rotation angle of the mirror plate 51 directly drives the mirror plate 51. It can be amplified rather than rotated.

According to an embodiment, as shown in FIG. 9, the scanning micromirror 10 may rotate the mirror plate 51 and the inner gamble 53 in the same direction about the third elastic body 52.

In addition, as shown in FIG. 10, the scanning micromirror 10 rotates the mirror plate 51 and the outer gamble 55 in the same direction about the third elastic body 52, and the inner gamble 53. Can also be rotated in the opposite direction.

The scanning micromirror 50 according to another embodiment of the present invention shown in FIG. 6 further includes the above-described sensor unit to adjust the rotation angles of the mirror plate 51, the inner gamble 53, and the outer gamble 55. It can be measured.

According to another embodiment of the present invention, the plurality of scanning micromirrors 10 may include a predetermined number of rows and a predetermined number of columns to form an M × N scanning micromirror array.

The scanning micromirror array may be used in an optical scanning device such as a projection display system, a head mounted display (HMD), or a laser printer.

Although the present invention has been described through the above embodiments, the above embodiments are merely intended to illustrate the spirit of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications may be made to the embodiments described above. The scope of the invention is defined only by the interpretation of the appended claims.

1 is a perspective view of a scanning micromirror according to an embodiment of the present invention.

2 and 3 are enlarged views of a sensor unit according to an embodiment of the present invention.

4 is an enlarged view of a sensor unit according to another exemplary embodiment of the present invention.

5 is a conceptual diagram of a Wheatstone bridge configured by a sensor unit according to another exemplary embodiment of the present invention.

6A is a perspective view of a scanning micromirror in accordance with another embodiment of the present invention.

6B-6E are conceptual and plan views illustrating the arrangement of windings in accordance with one embodiment of the present invention.

7 and 8 are exemplary diagrams illustrating driving of a scanning micromirror according to another exemplary embodiment of the present invention.

Claims (13)

A mirror plate for reflecting light; A gimbal provided around the mirror plate to support the mirror plate through a first elastic body; A support for supporting the gamble through a second elastic body; A winding through which current is provided in at least one of the gamble and the mirror plate; Magnetic material forming a magnetic field around the winding; A control unit for controlling a current flowing through the winding so that the mirror plate rotates the first elastic body about the axis and the gimbal rotates the second elastic body about the axis; And A sensor unit provided in at least one of the first elastic body and the second elastic body to measure rotation angles of the mirror plate and the gimbal, and including a piezoresistor whose resistance value changes according to the torsion of the first elastic body or the second elastic body; Including, The first or second elastic body is formed of silicon, the piezoresistor is arranged in parallel with any one of the crystal direction of the silicon. delete The method of claim 1, And the piezo resistor is arranged parallel to (110) in the crystal direction of the silicon when the silicon is n-type. The method of claim 1, And the piezo resistor is arranged parallel to (100) in the crystal direction of the silicon when the silicon is p-type. The method of claim 1, The sensor unit includes four piezoresistors, wherein the four piezoresistors form a Wheatstone bridge. 6. The method of claim 5, The sensor unit is a scanning micromirror provided so that one diagonal line of the Wheatstone bridge overlaps the central axis of the first elastic body or the second elastic body. The method according to claim 6, The control unit applies a predetermined voltage to two nodes of the Wheatstone bridge located on the central axis of the first elastic body or the second elastic body, and measures the rotation angle by measuring the voltage between the remaining two nodes. Scanning Micromirror. The method of claim 1, The sensor unit is a scanning micromirror located on the surface or inside of the first or second elastic body. The method of claim 1, The sensor unit is provided at the end of the gimbal of the both ends of the first elastic body, scanning micromirror is provided at the end of the support portion of both ends of the second elastic body. A mirror plate for reflecting light; An inner gamble provided around the mirror plate to support the mirror plate through a third elastic body; An outer gamble provided around the inner gamble and supporting the inner gamble through a fourth elastic body; A support for supporting the outer gamble through a fifth elastic body; Windings provided in the inner and outer gambles, through which current flows; Magnetic material forming a magnetic field around the winding; And A control unit for controlling the current flowing through the winding so that the mirror plate and the inner gamble rotate in the opposite phase with respect to the third elastic body, and the outer gamble rotates the fifth elastic body with the axis; Scanning micromirror comprising a. The method of claim 10, And the third elastic body and the fourth elastic body are in a straight line, and the fifth elastic body is perpendicular to the third elastic body and the fourth elastic body. The method of claim 10, Scanning micromirrors having different elastic modulus of the third elastic body and the fourth elastic body. The method of claim 10, And the inner gamble is rotated in antiphase with the mirror plate to amplify the rotation angle of the mirror plate.

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