JP2012242595A - Optical scanner and image display apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress temperature rise caused by light irradiation.SOLUTION: An optical scanner comprises: a support part; a mirror attachment part to which a mirror reflecting light is attached; a pair of spring parts formed at both ends of the mirror attachment part so as to face each other and rotatably supporting the mirror attachment part with respect to the support part; and a driving part for rotationally driving the mirror attachment part. The pair of spring parts each include: a plate-like magnet attachment part with a slit formed, to which a permanent magnet is attached; a first spring rotatably supporting the magnet attachment part with respect to the support part; and a second spring provided on the almost same straight line with the first spring and rotatably supporting the mirror attachment part with respect to the magnet attachment part. The driving part includes a yoke arranged so as to surround the permanent magnet along a rotational axis of the mirror attachment part, and a coil wound around the yoke and exciting the yoke by conduction to generate a magnetic field acting on the permanent magnet.

Description

  The present invention relates to an optical scanning device and an image display device.

  Optical scanning devices that scan light by rotating a mirror are widely used in digital copying machines, laser printers, barcode readers, scanners, projectors, and the like. As the optical scanning device, a motor-driven polygon mirror, a galvanometer mirror, or the like has been used.

  On the other hand, along with recent advances in microfabrication technology, optical scanning devices using MEMS (Micro Electro Mechanical Systems) technology have been greatly developed. As an optical scanning device using the MEMS technology, both ends of a mirror mounting portion on which a mirror is mounted are supported by spring portions made of an elastic material, and the mirror mounting portion is rotated by using the spring portion as a rotation shaft. Some are optically scanned. Such an optical scanning device has a simple structure and can be integrally formed using a semiconductor process as compared with a motor-driven polygon mirror or the like, and thus can be reduced in size and cost. it can.

  In an image display device such as a projector using an optical scanning device, it is necessary to increase the light irradiation power in order to increase the brightness of the display image.

  In general, it is difficult to set the reflectance of light at the mirror to 100%, and a part of the light irradiated to the mirror is absorbed by the mirror and heat is generated. Further, when the light irradiation power is increased, the amount of heat generated by the mirror also increases.

  In the optical scanning device that rotates the mirror mounting portion using the spring portion as a rotation axis, heat generated by the mirror is radiated using the mirror mounting portion and the spring portion as a heat dissipation path. Here, if the heat generated by the mirror is not sufficiently dissipated, the mirror will be distorted, the temperature of the spring will rise, and the resonance frequency will deviate from the predetermined value, making it difficult to scan light stably. There is a problem of becoming.

  Therefore, in Patent Document 1 (Japanese Patent Laid-Open No. 2008-039861), an optical scanning that suppresses a temperature increase caused by light irradiation by attaching a heat sink to a surface of the mirror mounting portion opposite to the mirror mounting surface. An apparatus is disclosed.

  Patent Document 2 (Japanese Patent Laid-Open No. 2009-134029) includes a mirror mounting portion, a support portion, a plate-like member connected via a mirror mounting portion and a support portion and a spring portion, and a plate-like member. In an optical scanning device having an electrode opposed to the lower surface of a member, and rotating and driving the mirror mounting portion using an electrostatic force between the electrode and the plate-like member generated by applying a voltage to the electrode. An optical scanning device is disclosed in which a heat sink is attached to the upper surface of the member via a bonding film.

JP 2008-039861 A JP 2009-134029 A

  In the optical scanning device disclosed in Patent Document 1, since the heat sink is attached, there is a problem that the moment of inertia of the mirror mounting portion increases, and the drive energy for rotating the mirror mounting portion increases.

  In the optical scanning device disclosed in Patent Document 2, heat generated in the mirror mounting portion is transmitted to the plate-like member via the spring portion, and further transferred to the bonding film and the heat sink to be dissipated. Here, since the bonding film provides resistance to heat dissipation, the optical scanning device disclosed in Patent Document 2 has a problem that the effect of heat dissipation is reduced.

  An object of the present invention is to provide an optical scanning device and an image display device capable of suppressing a temperature rise caused by light irradiation and performing stable light scanning while suppressing an increase in driving energy. It is in.

In order to achieve the above object, an optical scanning device of the present invention comprises:
A support part;
A mirror mounting portion on which a mirror that reflects light is mounted;
A pair of spring portions formed opposite to each other at both ends of the mirror mounting portion, and rotatably supporting the mirror mounting portion with respect to the support portion;
A drive unit that rotationally drives the mirror mounting unit,
Each of the pair of spring portions is
A plate-shaped magnet mounting part in which a permanent magnet is mounted and a slit is formed;
A first spring that rotatably supports the magnet mounting portion with respect to the support portion;
A second spring provided on substantially the same straight line as the first spring and rotatably supporting the mirror mounting portion with respect to the magnet mounting portion;
The drive unit is
A yoke arranged so as to surround the permanent magnet along the rotation axis of the mirror mounting portion;
A coil wound around the yoke and energizing the yoke by conduction to generate a magnetic field acting on the permanent magnet.

In order to achieve the above object, an image display device of the present invention provides:
A light beam generator for generating a modulated light beam;
And the above-described optical scanning device that reflects and scans the luminous flux.

  ADVANTAGE OF THE INVENTION According to this invention, while suppressing the increase in drive energy, the temperature rise resulting from light irradiation can be suppressed, and the stable light scanning can be performed.

1 is a top view of an optical scanning device according to a first embodiment of the present invention. 1B is a top view of the main frame shown in FIG. 1A. FIG. It is sectional drawing along the A-A 'line of FIG. 1A. 1B is a perspective view of the main frame shown in FIG. 1A. FIG. 1B is a perspective view of the optical scanning device shown in FIG. 1A. FIG. It is a figure which shows the left deflection | deviation state of the optical scanning device shown to FIG. 1A. It is a figure which shows the right deflection | deviation state of the optical scanning device shown to FIG. 1A. It is a figure for demonstrating the thermal radiation effect in the optical scanning device shown to FIG. 1A. It is a figure which shows the structural example of the image display apparatus provided with the optical scanning device of this invention. It is a top view which shows the other structure of the optical scanning device of the 1st Embodiment of this invention. It is sectional drawing along the A-A 'line of FIG. 6A. It is a figure which shows the left deflection | deviation state of the optical scanning device shown to FIG. 6A. It is a figure which shows the right deflection state of the optical scanning device shown to FIG. 6A. It is a top view of the main frame in the optical scanning device of the 2nd embodiment of the present invention. It is sectional drawing along the B-B 'line of FIG. 8A.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated with reference to drawings.

(First embodiment)
FIG. 1A is a top view of the optical scanning device 1 according to the first embodiment of the present invention. FIG. 1B is a top view of the main frame of the optical scanning device 1 shown in FIG. 1A. 1C is a cross-sectional view taken along line AA ′ of FIG. 1A.

  As illustrated in FIG. 1A, the optical scanning device 1 of the present embodiment includes a mirror 2, a permanent magnet 3, a main frame 10, and a drive unit 20.

  As shown in FIG. 1B, the main frame 10 includes a mirror mounting part 11, a support part 12, and a pair of spring parts 13. Each of the pair of spring portions 13 includes a magnet mounting portion 14, a first spring 15, and a second spring 16.

  The drive unit 20 includes a yoke 21 and a coil 25, as shown in FIG. 1C.

  For example, the mirror 2 uses glass as a substrate, and a dielectric multilayer film is coated on the glass as a reflective film that reflects light. The mirror 2 is formed in a rectangular shape, for example, and is fixed to the mirror mounting portion 11 using an adhesive or the like.

  The permanent magnet 3 is composed of, for example, a samarium cobalt magnet or a neodymium magnet, and is fixed to the magnet mounting portion 14 using an adhesive or the like.

  The main frame 10 includes a mirror mounting portion 11, a support portion 12, and a pair of spring portions 13 (magnet mounting portion 14, first spring 15, and second spring 16), such as a single crystal silicon substrate, stainless steel, or the like. Nonmagnetic material substrates having moderate rigidity, such as metal substrates, are integrally formed with each other. Further, the main frame 10 is fixed to the base not shown in FIGS. 1A to 1C at the support portion 12.

  Hereinafter, details of the configuration of the main frame 10 will be described with reference to FIGS. 1B and 2A. FIG. 2A is a perspective view of the main frame 10.

  The mirror mounting portion 11 is formed in a frame shape, and the mirror 2 is mounted on the upper surface of the frame.

  The support part 12 is fixed to the base 4 as shown in FIG. 2A.

  The pair of spring portions 13 are formed at both ends of the mirror mounting portion 11 so as to face each other, extend along the X axis substantially parallel to the mirror mounting surface of the mirror mounting portion 11, and extend between the mirror mounting portion 11 and the support portion 12. And the mirror mounting portion 11 is supported so as to be rotatable around the X axis with respect to the support portion 12.

  The magnet mounting portion 14 is plate-shaped and has a hole portion 14a into which the permanent magnet 3 is fitted and mounted. Moreover, the magnet mounting part 14 has the slit part 14b in which the slit was formed. The slit part 14b functions as a radiation fin. If the position of the center of gravity of the magnet mounting portion 14 deviates from the X axis, unnecessary vibration is likely to occur during driving, and it becomes difficult to perform stable optical scanning. Therefore, it is desirable that the slit portion 14b is formed symmetrically with respect to the X axis.

  The first spring 15 connects the support portion 12 and the magnet mounting portion 14 and supports the magnet mounting portion 14 so as to be rotatable about the X axis with respect to the support portion 12.

  The second spring 16 is formed on substantially the same straight line as the first spring 15, connects the magnet mounting portion 14 and the mirror mounting portion 11, and can rotate the mirror mounting portion 11 with respect to the magnet mounting portion 14. To support.

  The drive unit 20 drives the mirror mounting unit 11 to rotate about the X axis.

  Hereinafter, details of the configuration of the drive unit 20 will be described with reference to FIGS. 1C and 2B. 2B is a perspective view of the optical scanning device 1. FIG.

  As shown in FIG. 1C, the permanent magnet 3 is mounted so as to be substantially rotationally controlled with respect to the X axis (the rotation axis of the mirror mounting portion 11), and has a magnetization direction as indicated by an arrow M. It is mounted so as to be orthogonal to the X axis and parallel to the main surface of the magnet mounting portion 14.

  The yoke 21 is formed of a magnetic material including, for example, an iron-based material, a ferrite material, or a permalloy material, and is disposed so as to surround the permanent magnet 3 along the X axis. The yoke 21 has a first yoke part 22, a second yoke part 23, and a third yoke part 24.

  The first yoke portion 22 has one end portion 22a (hereinafter referred to as the first end portion 22a) in the vicinity of the permanent magnet 3.

  The second yoke portion 23 is in the vicinity of the permanent magnet 3 and has one end portion 23a (hereinafter referred to as a second end portion) facing the first end portion 22a with the permanent magnet 3 sandwiched in a direction substantially orthogonal to the magnetization direction of the permanent magnet 3. The end portion 23a of the first yoke portion 22 extends.

  The third yoke portion 24 magnetically couples the other end portion 22 b of the first yoke portion 22 and the other end portion 23 b of the second yoke portion 23.

  Therefore, the first yoke portion 22, the second yoke portion 23, and the third yoke portion 24 are magnetically coupled to each other to form the yoke 21 as one magnetic circuit. In addition, the gap of the 1st edge part 22a and the 2nd edge part 23a is the range of 1-2 mm as an example.

  The coil 25 is wound around the third yoke portion 24 and becomes conductive, thereby exciting the first yoke portion 22, the second yoke portion 23, and the third yoke portion 24, and acting on the permanent magnet 3. Generate a magnetic field. Moreover, the coil 25 is comprised so that a mutually different magnetic pole may be formed in the 1st end part 22a and the 2nd end part 23a by electrically conducting so that it may mention later. The number of turns of the coil is 200 as an example.

Here, when the gap between the first end 22a and the second end 23a is g, and the number of turns and current of the coil 25 are N and I, respectively, the magnitude of the magnetic field H generated between the gaps g is , Approximately H = NI / g. For example, when the number of coil turns N is 200, the current I is 200 mA, and the gap g is 2 mm, the magnetic field H acting on the permanent magnet 3 is 2 × 10 ⁴ A / m (250 Oe).

  Next, the operation of the optical scanning device 1 will be described.

  When the coil 25 is energized, a magnetic flux is generated in the first yoke part 22, the second yoke part 23, and the third yoke part 24, and a magnetic pole is formed in each yoke part. At this time, as shown in FIGS. 3A and 3B, magnetic poles different from each other are formed on the first end 22a and the second end 23a. As a result, a magnetic field is generated between the first end 22a and the second end 23a.

  When a current in a predetermined direction is passed through the coil 25, an N pole is generated at the first end 22a and an S pole is generated at the second end 23a, as shown in FIG. 3A. Due to the magnetic pole generated at each end, a magnetic field is generated in the direction from the first end 22a to the second end 23a. The magnetic field acts on the permanent magnet 3, and the permanent magnet 3 (that is, the magnet mounting portion 14) is tilted to the left as viewed in the figure so that the N pole of the permanent magnet 3 attracts the S pole of the second end 23a. (Left deflection state).

  On the other hand, when a current in the direction opposite to the predetermined direction is passed through the coil 25, an S pole is generated at the first end 22a and an N pole is generated at the second end 23a, as shown in FIG. 3B. . Due to the magnetic poles generated at each end, a magnetic field is generated from the second end 23a toward the first end 22a. This magnetic field acts on the permanent magnet 3, and the permanent magnet 3 (that is, the magnet mounting portion 14) is tilted to the right as viewed in the figure so that the north pole of the permanent magnet 3 attracts the south pole of the first end 22a. (Right deflection state).

  As the magnet mounting portion 14 is tilted, the mirror mounting portion 11 is tilted in the same direction as the magnet mounting portion 14. Therefore, light incident at a certain angle can be reflected, for example, at a shallow angle on the one hand and at a deep angle on the other hand. In this way, by changing the direction and magnitude of the current flowing through the coil 25, the angle of the scanning light can be arbitrarily set.

  Here, the system comprising the mirror 2, the permanent magnet 3, the mirror mounting portion 11, the magnet mounting portion 14, the first spring 15, and the second spring 16 is a torsional resonance mode in which reciprocating rotation about the X axis is performed. Have

  A sinusoidal current is passed through the coil 25, and by making the frequency of the sinusoidal current coincide with the frequency of the resonance mode of the system described above, the system described above causes torsional resonance, and a large mirror rotation angle with a small current. The reciprocating rotation having can be obtained.

  Next, the heat radiation effect in the optical scanning device 1 of the present embodiment will be described.

  As described above, part of the light irradiated on the mirror 2 is absorbed by the mirror 2 and becomes heat. The heat generated in the mirror 2 is transmitted from the mirror mounting portion 11 and the second spring 16 to the magnet mounting portion 14.

  Since the magnet mounting part 14 has a slit formed in the slit part 14b, the surface area increases, and the heat generated in the mirror 2 can be effectively dissipated.

  The optical scanning device disclosed in Patent Document 2 is a plate-like member (mass parts 21, 22) connected between the mirror mounting part and the support part via the mirror mounting part, the support part, and the spring part. And a heat sink is provided on the plate-like member. However, in the configuration in which the heat sink is provided on the plate-like member as described above, the plate-like member receives a large air resistance, and the driving efficiency is drastically reduced.

  Furthermore, it is difficult to provide a slit in the plate member of the optical scanning device disclosed in Patent Document 2. In the optical scanning device disclosed in Patent Document 2, an electrode 32 is provided in a corresponding portion of the mass parts 21 and 22, a driving voltage is applied between the mass part and the electrode, and electrostatic force generated by the driving voltage is used. The mirror is driven to rotate. Accordingly, the electrostatic force generated when the slit is formed in the mass part is drastically reduced.

  On the other hand, in the optical scanning device 1 of the present embodiment, since the slit 14b is provided in the magnet mounting portion 14, as shown in FIG. Stream F is generated. Therefore, an increase in air resistance during driving can be suppressed, and an increase in driving energy can also be suppressed.

   Further, in the optical scanning device 1 of the present embodiment, the electromagnetic force acting on the permanent magnet mounted on the magnet mounting portion 14 is used as a driving force, and a magnet is disposed in a part of the magnet mounting portion to provide a slit. However, the driving force is not drastically reduced.

  In general, the permanent magnet 3 has a characteristic that the magnetic force decreases as the temperature increases. When the magnetic force of the permanent magnet 3 is reduced, the driving force for rotationally driving the mirror mounting portion 11 is also reduced, and a desired deflection angle of the mirror mounting portion 11 cannot be ensured. Therefore, as in the present embodiment, the temperature increase of the permanent magnet 3 can be suppressed by providing the magnet mounting portion 14 with the slit portion 14b.

  Further, as disclosed in Patent Document 1, if a heat sink is provided in the mirror mounting portion, the moment of inertia of the mirror mounting portion increases. Further, since the rotation angle of the heat sink and the rotation angle of the mirror (mirror mounting portion) are equal, the driving energy for driving the mirror mounting portion having a large moment of inertia increases.

  On the other hand, in this embodiment, if the magnet mounting part 14 is provided in the middle of the mirror mounting part 11 and the support part 12 (the length of the first spring 15 and the length of the second spring 16 are the same). The rotation angle of the slit portion 14 b formed in the magnet mounting portion 14 is half the rotation angle of the mirror mounting portion 11. Therefore, as disclosed in Patent Document 1, an increase in driving energy for driving the mirror mounting portion can be suppressed rather than providing a heat sink in the mirror mounting portion. The rotation of the slit portion 14b is achieved by providing the magnet mounting portion 14 closer to the support portion 12 than the mirror mounting portion 11 (the length of the first spring 15 is shorter than the length of the second spring 16). The angle can be further reduced, and an increase in driving energy can be suppressed. Therefore, in the present embodiment, the magnet mounting portion 14 is desirably provided closer to the support portion 12 than the mirror mounting portion 11.

  Thus, according to the present embodiment, the optical scanning device 1 is connected to the mirror mounting portion 11 and the support portion 12 via the second spring 16 and the first spring 15, respectively, and has a slit. It has a magnet mounting part 14.

  The heat generated in the mirror 2 due to the light irradiation is transmitted from the mirror mounting portion 11 to the second spring 16 and the mirror mounting portion 14. Since the mirror mounting portion 14 is provided with a slit, the surface area is increased, and the heat generated in the mirror mounting portion 11 can be effectively radiated. As a result, the temperature rise of the mirror 2, the permanent magnet 3, the spring part 13, etc. can be suppressed, and the optical scanning device 1 can be driven stably.

  Moreover, by providing the slit part 14b in the magnet mounting part 14, it is possible to radiate heat generated in the mirror 2 while suppressing an increase in air resistance during driving and suppressing an increase in driving energy.

  Moreover, it is possible to prevent an increase in assembly man-hours by forming the respective parts constituting the main frame 10 integrally with each other.

  Here, the configuration and operation of the image display apparatus in which the optical scanning device 1 of the present embodiment is incorporated will be described.

  FIG. 5 is a diagram illustrating a configuration example of an image display device including the optical scanning device 1 according to the present embodiment.

  The image display apparatus shown in FIG. 5 generates a luminous flux P1 that generates a luminous flux of each color that is modulated according to a video signal supplied from the outside, and collimates each luminous flux generated by the luminous flux generation apparatus P1. The collimating optical system P2 and the combining optical system P3 for combining the collimated light beams. Further, the image display device scans in the vertical direction the horizontal scanning unit P4 that scans in the horizontal direction in order to display the image of the light beam synthesized by the synthesis optical system P3, and the light beam scanned in the horizontal direction in the horizontal scanning unit P4. And an optical system (not shown) for emitting light beams scanned in the horizontal direction and the vertical direction onto the screen. The optical scanning device 1 of this embodiment is incorporated in an image display device as a scanning mirror P41 of a horizontal scanning unit P4.

  The luminous flux generation device P1 generates a signal that is an element for constructing an image based on a video signal supplied from the outside, and is used in the horizontal synchronization signal used in the horizontal scanning unit P4 and in the vertical scanning unit P5. Signal processing circuits for outputting the vertical synchronizing signals respectively. In this signal processing circuit, red (R), green (G), and blue (B) video signals are generated.

  Further, the light flux generation device P1 has a light source section P11 that generates light fluxes corresponding to the three video signals (R, G, B) output from the signal processing circuit. The light source unit P11 includes a laser P12 that generates a light beam for each color of the video signal, and a laser drive system P13 that drives the laser P12. As each laser P12, a semiconductor laser or a solid-state laser with a harmonic generation mechanism (SHG) is preferably used.

  The light beams of the respective colors emitted from the lasers P12 of the light beam generation device P1 are collimated by the collimating optical system P2, and then enter the dichroic mirrors corresponding to the colors of the combining optical system P3. The light beams of the respective colors incident on the dichroic mirrors are reflected or transmitted in a wavelength selective manner and are output to the horizontal scanning unit P4.

  The horizontal scanning unit P4 and the vertical scanning unit P5 scan the scanning mirrors P41 and P51 in the horizontal direction and the vertical direction and project the light beam incident on the horizontal scanning unit P4 as an image. The scanning mirrors P41 and P51 are driven by a scanning drive circuit based on a synchronization signal output from the signal processing circuit and input through the scanning synchronization circuit.

  In the present embodiment, the configuration of the drive unit is not limited to the configuration illustrated in FIG. 1C. Below, with reference to FIG. 6A and FIG. 6B, the optical scanning apparatus 1A which has a structure different from the optical scanning apparatus 1 in this embodiment is demonstrated.

  FIG. 6A is a top view of the optical scanning device 1A. FIG. 6B is a cross-sectional view taken along the line A-A ′ of FIG. 6A. 6A and 6B, the same reference numerals are given to the same components as those in FIGS. 1A to 1C, and description thereof will be omitted.

  The optical scanning device 1A is different from the optical scanning device 1 in that the configuration of the drive unit is changed. Specifically, in the optical scanning device 1 </ b> A, the driving unit 20 in the optical scanning device 1 is changed to a driving unit 30.

  Referring to FIG. 6B, the driving unit 30 includes a yoke 31 and a coil 35.

  The yoke 31 is formed of a magnetic material including, for example, an iron-based material, a ferrite material, or a permalloy material, and is disposed so as to surround the permanent magnet 3 along the X axis. The yoke 31 has a first yoke part 32, a second yoke part 33, and a third yoke part 34.

  The first yoke portion 32 has one end portion 32 a (hereinafter referred to as the first end portion 32 a) 211 a in the vicinity of the permanent magnet 3.

  The second yoke portion 33 is in the vicinity of the permanent magnet 3 and has one end portion 33a (hereinafter referred to as the first end portion 33a) facing the first end portion 32a with the permanent magnet 3 sandwiched in the same direction as the magnetization direction of the permanent magnet 3. 2 and called end portion 33a), and extends opposite to first yoke portion 32.

  The third yoke portion 34 has one end portion 34a (hereinafter referred to as a third end portion 34a) facing the permanent magnet 3 in a direction substantially orthogonal to the magnetization direction of the permanent magnet 3, and the first yoke portion. The other end portion 32 b of 32 and the other end portion 33 b of the second yoke portion 33 are magnetically coupled.

  Therefore, the first yoke part 32, the second yoke part 33, and the third yoke part 34 are magnetically coupled to each other to form a yoke 31 as one magnetic circuit. Note that the gap between the first end portion 32a and the third end portion 34a and the gap between the second end portion 33a and the third end portion 34a are each in the range of 1 to 2 mm, for example. .

  The coil 35 is wound around the third yoke portion 34 and becomes conductive, thereby exciting the first yoke portion 32, the second yoke portion 33, and the third yoke portion 34, and acting on the permanent magnet 3. Generate a magnetic field. Further, as will be described later, the coil 35 is configured to form different magnetic poles at the first end portion 32a, the second end portion 33a, and the third end portion 34a by conducting. . If the coil 35 is configured to be electrically conductive so that different magnetic poles are formed at the first end 32a and the second end 33a and the third end 34a, the first end 32a It may be wound around the yoke part 32 or the second yoke part 33.

  Next, the operation of the optical scanning device 1A will be described.

  When the coil 35 is energized, a magnetic flux is generated in the first yoke portion 32, the second yoke portion 33, and the third yoke portion 34, and a magnetic pole is formed in each yoke portion. At this time, as shown in FIGS. 7A and 7B, the same kind of magnetic pole is formed at the first end portion 32a and the second end portion 33a, and a different magnetic pole is formed at the third end portion 34a. The As a result, a magnetic field is generated between the first end portion 32a and the third end portion 34a and between the second end portion 33 and the third end portion 34a.

  When a current in a predetermined direction is passed through the coil 35, an N pole is generated at the first end portion 32a and the second end portion 33a, and an S pole is generated at the third end portion 34a, as shown in FIG. 7A. To do. Due to the magnetic pole generated at each end, a magnetic field is generated from the first end 32a and the second end 33a in the direction of the third end 34a. This magnetic field acts on the permanent magnet 3, and the permanent magnet 3 (that is, the magnet mounting portion 14) is tilted to the left as viewed in the figure so that the south pole of the permanent magnet 3 attracts the north pole of the second end 33a. (Left deflection state).

  On the other hand, when a current in a direction opposite to the predetermined direction is passed through the coil 35, as shown in FIG. 7B, the first end 32a and the second end 33a have S poles, and the third end 34a has Each has N poles. Due to the magnetic pole generated at each end, a magnetic field is generated from the third end 34a in the direction of the first end 32a and the second end 33a, respectively. The magnetic field acts on the permanent magnet 3, and the permanent magnet 3 (that is, the magnet mounting portion 14) is tilted to the right as viewed in the drawing so that the north pole of the permanent magnet 3 attracts the south pole of the first end portion 32a. (Right deflection state).

  As described above, in the optical scanning device 1 </ b> A, similarly to the optical scanning device 1, the mirror mounting portion 11 is tilted in the same direction as the magnet mounting portion 14 as the magnet mounting portion 14 is tilted. Therefore, light incident at a certain angle can be reflected, for example, at a shallow angle on the one hand and at a deep angle on the other hand. In this way, by changing the direction and magnitude of the current flowing through the coil 35, the angle of the scanning light can be arbitrarily set.

  Further, in the optical scanning device 1A, as in the optical scanning device 1, the system including the mirror 2, the permanent magnet 3, the mirror mounting portion 11, the magnet mounting portion 14, the first spring 15, and the second spring 16 is And a torsional resonance mode that reciprocates around the X axis.

  A sinusoidal current is passed through the coil 35, and by making the frequency of the sinusoidal current coincide with the frequency of the resonance mode of the system described above, the system described above causes torsional resonance, and a large mirror rotation angle with a small current. The reciprocating rotation having can be obtained.

  Further, in the optical scanning device 1A, similarly to the optical scanning device 1, since the slit portion 14b is formed in the magnet mounting portion 14, the heat generated by the mirror can be effectively radiated.

  As described above, also in the optical scanning device 1 </ b> A, similarly to the optical scanning device 1, the mirror mounting portion 11 is driven to rotate, and the temperature rise caused by the heat generated in the mirror 2 is suppressed by applying light. be able to.

  In the optical scanning device 1 and the optical scanning device 1A, one end of the yoke is formed with an acute-shaped cross section toward the permanent magnet 3, and is formed with a concavo-convex cross section. You may form so that the cross-sectional area of the one end part may reduce toward the permanent magnet 3, for example by forming with a protrusion. By forming the yoke in such a manner that the cross-sectional area of one end of the yoke is reduced toward the permanent magnet 3, the magnetic flux density at the end can be increased and the magnetic field acting on the permanent magnet 3 can be increased. As a result, the driving force can be increased and the touch angle of the mirror mounting portion 11 can be increased.

(Second Embodiment)
The optical scanning device of the present embodiment is different from the optical scanning device 1 and the optical scanning device 1A of the first embodiment in the configuration of the main frame. Specifically, the optical scanning device of the present embodiment is different from the optical scanning device 1 and the optical scanning device 1A of the first embodiment in that the main frame 10 is changed to the main frame 10B. In the following, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 8A is a top view of the main frame 10B of the present embodiment. 8B is a cross-sectional view taken along line B-B ′ of FIG. 8A. 8A and 8B show a state where the permanent magnet 3 is attached to the main frame 10B.

  As shown in FIG. 8A, the main frame 10B of the present embodiment has a magnet mounting portion 14 as a magnet mounting portion 81 as compared with the optical scanning device 1 of the first embodiment and the main frame 10 in the optical scanning device 1A. The changes are different.

  The magnet mounting portion 81 is plate-shaped, and has a slit portion 82 in which a plurality of slits are formed substantially parallel to each other while the permanent magnet 3 is mounted.

  As shown in FIG. 8B, the slit portion 82 includes a rising portion 82 a that protrudes upward with respect to the main surface of the magnet mounting portion 81 and a falling portion that protrudes downward with respect to the main surface of the magnet mounting portion 81. 82b. The rising portion 82a and the falling portion 82b can be easily formed using, for example, pressing.

  Thus, by forming the rising portion 82a and the falling portion 82b, the surface area of the slit portion 82 is increased and heat can be radiated more efficiently than simply forming the slit.

  When only the rising part 82a is formed or when only the falling part 82b is formed, the position of the center of gravity of the magnet mounting part 81 may deviate from the X axis. As described above, if the position of the center of gravity of the magnet mounting portion 81 deviates from the X axis, unnecessary vibration is likely to occur during driving, making it difficult to perform stable optical scanning. Therefore, in order to prevent the center of gravity of the magnet mounting portion 81 from deviating from the X axis, the rising portions 82a and the falling portions 82b are alternately formed, and the rising portions 82a and the falling portions 82b are formed in the same number. It is desirable to do so.

  The present invention is not limited to the above-described embodiments, and it is obvious that each embodiment can be appropriately changed within the scope of the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Optical scanning device 2 Mirror 3 Permanent magnet 4 Base 10 Main frame 11 Mirror mounting part 12 Support part 13 Spring part 14,81 Magnet mounting part 14a Hole part 14b, 82 Slit part 15 1st spring 16 2nd spring 20 , 30 Drive portion 21 Yoke 22, 32 First yoke portion 22a, 32a First end portion 22b, 32b Other end portion 23, 33 Second yoke portion 23a, 33a Second end portion 23b, 33b Other end portion 24, 34 Third yoke portion 34a Third end portion 25, 35 Coil 82a Rising portion 82b Falling portion P1 Light beam generation device P11 Light source portion P12 Laser P13 Laser drive system P2 Collimating optical system P3 Composite optical system P4 Horizontal scanning portion P41 Scanning mirror P5 Vertical scanning unit P51 Scanning mirror

Claims (11)

A support part;
A mirror mounting portion on which a mirror that reflects light is mounted;
A pair of spring portions formed opposite to each other at both ends of the mirror mounting portion, and rotatably supporting the mirror mounting portion with respect to the support portion;
A drive unit that rotationally drives the mirror mounting unit,
Each of the pair of spring portions is
A plate-shaped magnet mounting part in which a permanent magnet is mounted and a slit is formed;
A first spring that rotatably supports the magnet mounting portion with respect to the support portion;
A second spring provided on substantially the same straight line as the first spring and rotatably supporting the mirror mounting portion with respect to the magnet mounting portion;
The drive unit is
A yoke arranged so as to surround the permanent magnet along the rotation axis of the mirror mounting portion;
An optical scanning device comprising: a coil wound around the yoke and exciting the yoke by conduction to generate a magnetic field acting on the permanent magnet. The optical scanning device according to claim 1,
The permanent magnet is arranged so as to be substantially rotationally symmetric with respect to the rotation axis, and is arranged so that the magnetization direction is substantially orthogonal to the rotation axis. The optical scanning device according to claim 2.
The yoke has two end portions facing each other with the permanent magnet sandwiched in substantially the same direction as the magnetization direction of the permanent magnet, and one end facing the permanent magnet in a direction substantially perpendicular to the magnetization direction of the permanent magnet. An end, and
The optical scanning device according to claim 1, wherein the coil is wound around the yoke so as to form different magnetic poles at the two end portions and the one end portion by conduction. The optical scanning device according to claim 2.
The yoke portion has two end portions facing each other across the permanent magnet in a direction substantially perpendicular to the magnetization direction of the permanent magnet,
The optical scanning device according to claim 1, wherein the coil is wound around the yoke portion so as to form different magnetic poles at the two end portions by conduction. In the optical scanning device according to any one of claims 1 to 4,
The optical scanning device, wherein the mirror mounting portion is frame-shaped. The optical scanning device according to any one of claims 1 to 5,
The optical scanning device characterized in that the first spring is shorter than the second spring. In the optical scanning device according to any one of claims 1 to 6,
The slit is formed with a rising portion protruding upward with respect to the main surface of the magnet mounting portion and a falling portion protruding downward with respect to the main surface of the magnet mounting portion. An optical scanning device. The optical scanning device according to claim 7.
The optical scanning device, wherein the rising portion and the falling portion are alternately formed. The optical scanning device according to claim 7 or 8,
The number of the rising parts and the falling parts are the same. The optical scanning device according to any one of claims 1 to 9,
The optical scanning device characterized in that the slit is formed symmetrically with respect to the rotation axis. A light beam generator for generating a modulated light beam;
An image display device comprising: the optical scanning device according to claim 1 that reflects and scans the light flux.

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