Actuator

Abstract

To provide an actuator for vibrating an optical element, which can enhance durability of a fulcrum section to be a rotation fulcrum of a movable body for holding the optical element even when the optical element continuously vibrates with a relatively high frequency.SOLUTION: In an actuator 1, a fulcrum section 6 to be a rotation fulcrum of a movable body 3 with respect to a fixed body 4 includes: a ceramic spherical body 11; a spherical body holding member 12 which is mounted in the movable body 3 and is used for holding the spherical body 11; and a spherical body support member 13 which is mounted in the fixed body 4. The spherical body 11 is arranged on an inner peripheral side of a cylindrical section of the spherical body holding member 12 formed into a bottomed cylindrical shape. A through hole for arranging a part of the spherical body 11 arranged on the inner peripheral side of the cylindrical section outside the spherical body holding member 12 is formed at the bottom of the spherical body holding member 12. A contact surface of a concave surface formed in the spherical body support member 13 is brought into contact with a part of the spherical body 11 arranged outside the spherical body holding member 12 with a prescribed contact pressure.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an actuator for vibrating an optical element.

Background Art

[0002] Conventionally, a pixel shift device for vibrating a glass plate (optical glass) through which projected light passes has been known (see, for example, Patent Document 1). The pixel shift device described in Patent Document 1 is mounted on a projector. This pixel shift device includes a glass frame to which a glass plate is fixed and a base that rotatably holds the glass frame. The glass frame and the base are formed in a rectangular frame shape. The glass plate is disposed on the inner peripheral side of the glass frame. The glass frame is disposed on the inner peripheral side of the base.

[0003] In the pixel shift device described in Patent Document 1, a bearing and a core shaft that serve as a fulcrum for the rotation of the glass frame with respect to the base are disposed between the glass frame and the base. The core shaft is fixed to the glass frame so as to project to the outer peripheral side of the glass frame on one diagonal line of the glass frame having a rectangular frame shape. The bearing is fixed to the base at a corner on one diagonal line of the base having a rectangular frame shape. The bearing is a sliding bearing formed in a cylindrical shape. The core shaft is inserted into the inner peripheral side of the bearing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the pixel shifting device described in Patent Document 1, the glass frame vibrates continuously at a relatively high frequency together with the glass plate. For example, in this pixel shifting device, the glass frame vibrates continuously at 60 Hz. Therefore, in this pixel shifting device, it is preferable that the durability of the pivot point, which serves as the pivot point for the rotation of the glass frame relative to the base, is high.

[0006] Therefore, the object of the present invention is to provide an actuator for vibrating an optical element that can increase the durability of the pivot point, which is the pivot point for the rotation of the movable body that holds the optical element, even when the optical element vibrates continuously at a relatively high frequency. [Means for solving the problem]

[0007] To solve the above problems, the actuator of the present invention comprises a movable body that holds an optical element, a fixed body formed in the shape of a frame and positioned on the inner circumference side of the movable body and rotatably holding the movable body, a magnetic drive mechanism that rotates the movable body in a direction in which the movable body is tilted relative to the fixed body, and a pivot point that serves as the pivot point for the rotation of the movable body relative to the fixed body. The pivot point comprises a ceramic sphere, a sphere holding member attached to either the movable body or the fixed body and for holding the sphere, and a sphere support member having a concave curved contact surface that contacts a part of the sphere with a predetermined contact pressure and attached to the other of the movable body or the fixed body. The sphere holding member is formed in the shape of a bottomed cylinder having a cylindrical part and a bottom connected to one end of the cylindrical part, the sphere is positioned on the inner circumference side of the cylindrical part, and a through hole is formed in the bottom to position a part of the sphere positioned on the inner circumference side of the cylindrical part outside the sphere holding member, and the contact surface is in contact with a part of the sphere positioned outside the sphere holding member.

[0008] In the actuator of the present invention, the pivot point is provided with a ceramic sphere. Therefore, in the present invention, it is possible to increase the durability of the pivot point even when the optical element vibrates continuously at a relatively high frequency. Furthermore, in the present invention, the sphere holding member for holding the sphere is formed in the shape of a bottomed cylinder having a cylindrical portion on the inner circumference side where the sphere is positioned and a bottom portion connected to one end of the cylindrical portion. A through hole is formed in the bottom portion to allow a part of the sphere positioned on the inner circumference side of the cylindrical portion to be positioned outside the sphere holding member. Therefore, in the present invention, even if the sphere is made of ceramic and the outer diameter of the sphere is small, it is possible to easily attach a sphere that has a part of it in contact with the contact surface of the sphere support member outside the sphere holding member to a movable or fixed body using the sphere holding member.

[0009] In the present invention, for example, the optical element is formed in the shape of a flat plate, and the pivot points are arranged on both ends of the movable body in a first orthogonal direction perpendicular to the thickness direction of the optical element.

[0010] In the present invention, for example, the sphere holding member is attached to a movable body, and the sphere support member is attached to a fixed body. The movable body has projections that protrude toward both sides in a first orthogonal direction and are inserted into a cylindrical portion. A recess is formed on the tip surface of the projection where a part of the sphere is placed, and the contact surface contacts a part of the sphere from the outside in the first orthogonal direction. In this case, since a recess is formed on the tip surface of the projection where a part of the sphere is placed, it becomes possible to stabilize the state of the sphere attached to the movable body.

[0011] In the present invention, the spherical support member is a leaf spring formed in a U shape, and it is preferable that the shape of the leaf spring when viewed from the thickness direction of the optical element is U-shaped. With this configuration, it becomes possible to miniaturize the leaf spring in the thickness direction of the optical element compared to the case where the shape of the leaf spring when viewed from a direction perpendicular to the thickness direction of the optical element and the first orthogonal direction is U-shaped. Therefore, it becomes possible to miniaturize the actuator in the thickness direction of the optical element.

[0012] In the present invention, the actuator comprises a leaf spring having spherical support members arranged at each end of the movable body in a first orthogonal direction and a flat plate-shaped connecting portion connecting the two spherical support members, wherein the connecting portion is formed in a frame shape and may be fixed to one side of the movable body or fixed body in the thickness direction of the optical element.

[0013] In this case, since the two spherical support members are integrated via a connecting portion, it is possible to reduce the number of actuator parts compared to the case where two separate spherical support members are provided. Furthermore, in this case, since the two spherical support members are attached to the movable or fixed body by fixing the connecting portion to the movable or fixed body, it is possible to reduce the assembly man-hours of the actuator compared to the case where each of the two separately formed spherical support members is fixed to the movable or fixed body.

[0014] Furthermore, in this case, since the two spherical support members are attached to the movable or fixed body by fixing the frame-shaped connecting part to the movable or fixed body, it is possible to secure the fixing area of ​​the connecting part to the movable or fixed body and increase the mounting strength of the spherical support members to the movable or fixed body. In addition, in this case, the two spherical support members are integrated via the connecting part, and the variation in the relative positions of the two spherical support members is determined by the precision of the leaf spring components, so it is possible to suppress the variation in the relative positions of the two spherical support members compared to the case where each of the two spherical support members, which are formed separately, is fixed to the movable or fixed body.

[0015] In the present invention, it is preferable that reinforcing ribs are formed on the spherical support member. With this configuration, it is possible to ensure the strength of the spherical support member even if the thickness of the spherical support member is reduced. [Effects of the Invention]

[0016] As described above, in the present invention, even when the optical element vibrates continuously at a relatively high frequency in the actuator for vibrating the optical element, it is possible to enhance the durability of the fulcrum portion that serves as the pivot point of the movable body that holds the optical element.

Brief Description of the Drawings

[0017] [Figure 1] It is a perspective view of an actuator according to an embodiment of the present invention. [Figure 2] It is a plan view of the actuator shown in FIG. 1. [Figure 3] It is an exploded perspective view of the actuator shown in FIG. 1. [Figure 4] (A) is a cross-sectional view taken along the line E-E of FIG. 2, and (B) is a cross-sectional view taken along the line F-F of FIG. 2. [Figure 5] It is an enlarged view of the sphere, the sphere holding member, and the sphere supporting member shown in FIG. 3. [Figure 6] It is an enlarged view for explaining the configuration of the G portion in FIG. 2. [Figure 7] It is a view of a leaf spring according to another embodiment of the present invention, where (A) is a plan view and (B) is a perspective view. [Figure 8] It is a plan view for explaining the configuration of the fulcrum portion according to another embodiment of the present invention. [Figure 9] It is an enlarged view of the J portion in FIG. 7(B).

Modes for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0019] (Overall Configuration of the Actuator) FIG. 1 is a perspective view of an actuator 1 according to an embodiment of the present invention. FIG. 2 is a plan view of the actuator 1 shown in FIG. 1. FIG. 3 is an exploded perspective view of the actuator 1 shown in FIG. 1.

[0020] In the following explanation, as shown in Figure 1, the three mutually orthogonal directions will be referred to as the X, Y, and Z directions, with the X direction being the left-right direction, the Y direction being the front-back direction, and the Z direction being the up-down direction. Furthermore, one side of the left-right direction, the X1 direction in Figure 1, will be referred to as the "right" side, and the opposite side, the X2 direction in Figure 1, will be referred to as the "left" side. One side of the front-back direction, the Y1 direction in Figure 1, will be referred to as the "front" side, and the opposite side, the Y2 direction in Figure 1, will be referred to as the "back" side. One side of the up-down direction, the Z1 direction in Figure 1, will be referred to as the "up" side, and the opposite side, the Z2 direction in Figure 1, will be referred to as the "down" side.

[0021] The actuator 1 in this embodiment is a device for vibrating optical glass 2 as an optical element, and is used mounted on a projector. The optical glass 2 is a glass plate that transmits light and is formed in the shape of a square flat plate. The optical glass 2 constitutes part of the projection optical system of the projector. The actuator 1 vibrates the optical glass 2 at a predetermined frequency and a constant angle to periodically change the orientation of the optical glass 2 in order to improve the image quality of the image projected by the projector. For example, the actuator 1 vibrates the optical glass 2 at 60 Hz.

[0022] The actuator 1 is formed in the shape of a flat rectangular parallelepiped, with a thin thickness in the vertical direction as a whole. The actuator 1 comprises a movable body 3 that holds the optical glass 2 and a fixed body 4 that rotatably holds the movable body 3. The movable body 3 and the fixed body 4 are formed in the shape of a frame. The optical glass 2 is positioned on the inner circumference side of the movable body 3. The movable body 3 is positioned on the inner circumference side of the fixed body 4. The actuator 1 also comprises a magnetic drive mechanism 5 that vibrates the optical glass 2 by rotating the movable body 3 in a direction that causes the movable body 3 to tilt relative to the fixed body 4, a pivot point 6 that serves as the pivot point for the rotation of the movable body 3 relative to the fixed body 4, and holding magnets 7 and magnetic plates 8, 9 for holding the movable body 3 in a fixed position relative to the fixed body 4 in the direction of rotation of the movable body 3 relative to the fixed body 4.

[0023] In this embodiment, when no current is supplied to the drive coil 16, which constitutes part of the magnetic drive mechanism 5 (i.e., when the drive coil 16 is de-energized), the movable body 3 is positioned at a predetermined reference position relative to the fixed body 4 in the direction of rotation of the movable body. When the movable body 3 is positioned at the reference position relative to the fixed body 4 in the direction of rotation of the movable body, the thickness direction and the vertical direction of the optical glass 2 coincide.

[0024] Furthermore, when the movable body 3 is positioned at a reference position relative to the fixed body 4 in the direction of rotation of the movable body, the actuator 1 mounted on the projector has the thickness direction of the optical glass 2 coincide with the optical axis direction of the projection optical system of the projector, and the optical axis of the projection optical system of the projector passes through the center of the optical glass 2. Note that the rotation angle of the movable body 3 relative to the fixed body 4 when the optical glass 2 vibrates is very small, for example, less than 0.5°. Therefore, regardless of whether the optical glass 2 is vibrating or not, the thickness direction of the optical glass 2 is almost coincided with the vertical direction.

[0025] The movable body 3 is rotatable in a direction that causes it to tilt relative to the fixed body 4 when viewed from the outer circumference of the fixed body 4. Furthermore, the movable body 3 is rotatable relative to the fixed body 4 with a first orthogonal direction (direction V in Figure 2), which is perpendicular to the thickness direction of the optical glass 2, as its axis of rotation. That is, the movable body 3 is rotatable relative to the fixed body 4 with axis L1 (see Figure 2), whose axis direction is the first orthogonal direction, as its pivot point. The first orthogonal direction is perpendicular to the vertical direction. Also, when viewed from above, the first orthogonal direction is shifted 45° clockwise in the direction of Figure 2 relative to the front-to-back direction. When viewed from the thickness direction of the optical glass 2, axis L1 passes through the center of the optical glass 2. The pivot points 6 are located at both ends of the movable body 3 in the first orthogonal direction.

[0026] The movable body 3 is a glass holder that holds the optical glass 2. The movable body 3 is made of a non-magnetic material. The movable body 3 is also made of a resin material. The movable body 3 is formed in a frame shape as described above. Specifically, the movable body 3 is formed in a square or rectangular frame shape. When the movable body 3 is positioned in a reference position relative to the fixed body 4 in the direction of rotation of the movable body, two of the four sides that make up the outer circumferential surface of the movable body 3, which has an outer shape of a square or rectangle, are parallel to the left-right direction, and the remaining two sides are parallel to the front-back direction.

[0027] The movable body 3 has a magnet arrangement recess 3a where the drive magnet 15, which will be described later and constitute part of the magnetic drive mechanism 5, is placed, and a magnet arrangement recess 3b where the holding magnet 7 is placed. The magnet arrangement recess 3a is recessed from the right end of the movable body 3 toward the left. The magnet arrangement recess 3b is recessed from the left end of the movable body 3 toward the right. The magnet arrangement recesses 3a and 3b are formed over the entire area of ​​the movable body 3 in the thickness direction of the optical glass 2.

[0028] Furthermore, the movable body 3 has projections 3c that protrude toward both sides in the first orthogonal direction. That is, the movable body 3 has a projection 3c that protrudes toward the right rear and a projection 3c that protrudes toward the left front. The projections 3c are formed in a cylindrical shape. The axial direction of the cylindrical projections 3c coincides with the first orthogonal direction. A recess 3d (see Figure 4) is formed on the tip surface of the projection 3c, where a part of the sphere 11, which will be described later and constitute part of the pivot point 6, is placed. The recess 3d is recessed toward the inside in the first orthogonal direction from the tip surface of the projection 3c. The recess 3d is also formed in a circular shape. The center of the circular recess 3d is located on the axis of the cylindrical projection 3c.

[0029] As described above, the optical glass 2 is positioned on the inner circumference of the movable body 3. The optical glass 2 is fixed to the movable body 3. When the movable body 3 is positioned in the reference position relative to the fixed body 4 in the direction of rotation of the movable body, two of the four sides that make up the outer surface of the optical glass 2, which has a square outer shape, are parallel to the left-right direction, and the remaining two sides are parallel to the front-back direction.

[0030] The fixed body 4 is made of a non-magnetic material. The fixed body 4 is also made of a resin material. As described above, the fixed body 4 is formed in a frame shape. Specifically, the fixed body 4 is formed in a square or rectangular frame shape. Of the four sides that make up the outer periphery of the fixed body 4, which has a square or rectangular outer shape, two sides are parallel to the left-right direction, and the remaining two sides are parallel to the front-back direction. The fixed body 4 has a coil arrangement recess 4a where the drive coil 16, which constitutes part of the magnetic drive mechanism 5 (described later), is arranged, and a magnetic plate arrangement recess 4b where the magnetic plate 9 is arranged.

[0031] The coil placement recess 4a and the magnetic plate placement recess 4b are formed on the right side of the fixed body 4. The coil placement recess 4a is recessed from the left end of the right side of the fixed body 4 toward the right. The coil placement recess 4a is formed over the entire vertical area of ​​the fixed body 4. The magnetic plate placement recess 4b is formed to the right of the coil placement recess 4a. The magnetic plate placement recess 4b is recessed further to the right than the coil placement recess 4a. The magnetic plate placement recess 4b is not formed over the entire vertical area of ​​the fixed body 4, and a magnetic plate mounting portion 4c on which the magnetic plate 9 is placed is formed on the lower end of the right side of the fixed body 4 (see Figure 2). The upper surface of the magnetic plate mounting portion 4c is a plane perpendicular to the vertical direction.

[0032] Furthermore, the fixed body 4 has a spring arrangement section 4d where a leaf spring 13, described later, which constitutes part of the pivot section 6, is arranged, and a magnetic plate arrangement hole 4e where the magnetic plate 8 is arranged and fixed. The spring arrangement section 4d is formed at two corners on one diagonal of the fixed body 4, which is formed in the shape of a square or rectangular frame. Specifically, the spring arrangement section 4d is formed at the right rear end corner and the left front end corner of the fixed body 4. The magnetic plate arrangement hole 4e is formed on the left side of the fixed body 4. The magnetic plate arrangement hole 4e is a through hole that penetrates the fixed body 4 in the vertical direction. Also, the magnetic plate arrangement hole 4e is a rectangular corner hole that is elongated in the front-to-back direction.

[0033] As described above, the pivot points 6 are located on both ends of the movable body 3 in the first orthogonal direction. Specifically, the pivot points 6 are located at the right rear corner and the left front corner of the actuator 1. The pivot point 6 comprises a spherical sphere (ball) 11, a sphere holding member 12 for holding the sphere 11, and a leaf spring 13 as a sphere support member, which has a concave curved contact surface 13a (see Figure 4, etc.) that contacts a part of the sphere 11 with a predetermined contact pressure. The specific configuration of the pivot point 6 will be described later.

[0034] The magnetic drive mechanism 5 comprises a drive magnet 15 and a drive coil 16 positioned opposite the drive magnet 15. The drive magnet 15 is fixed to the movable body 3. Specifically, the drive magnet 15 is positioned in a magnet arrangement recess 3a and fixed to the right side of the movable body 3. The drive magnet 15 is formed in the shape of an elongated rectangular parallelepiped in the front-rear direction. The drive magnet 15 is composed of two magnetized portions 15a that are polarized in the thickness direction of the optical glass 2.

[0035] The drive coil 16 is, for example, an air-core coil formed by winding a conductor in an air-core manner. The drive coil 16 is mounted on a flexible printed circuit board 17. The drive coil 16 is also positioned in a coil arrangement recess 4a. The flexible printed circuit board 17 is fixed to the fixed body 4. The drive coil 16 is fixed to the fixed body 4 via the flexible printed circuit board 17. The drive magnet 15 and the drive coil 16 are facing each other in the left-right direction.

[0036] The magnetic drive mechanism 5 rotates the movable body 3 relative to the fixed body 4 with the first orthogonal direction as the axis of rotation. A Hall sensor (not shown) is mounted on the flexible printed circuit board 17 to detect the rotational position of the movable body 3 relative to the fixed body 4. The Hall sensor is positioned opposite the drive magnet 15. Current is supplied to the drive coil 16 based on the detection result of the Hall sensor.

[0037] The retaining magnet 7 is fixed to the movable body 3. Specifically, the retaining magnet 7 is located in the magnet arrangement recess 3b and is fixed to the left side of the movable body 3. The retaining magnet 7 is formed in an elongated rectangular parallelepiped shape in the front-to-back direction. The retaining magnet 7 is configured similarly to the driving magnet 15 and consists of two magnetized parts 7a that are polarized in the thickness direction of the optical glass 2.

[0038] As shown in Figure 2, the front-to-back center of the retaining magnet 7 and the front-to-back center of the driving magnet 15 are offset in the front-to-back direction. Specifically, the front-to-back center of the retaining magnet 7 is located behind the front-to-back center of the driving magnet 15. In this embodiment, when viewed from the thickness direction of the optical glass 2, the retaining magnet 7 and the driving magnet 15 are positioned point-symmetrically with respect to the center of the movable body 3. Also, when viewed from the thickness direction of the optical glass 2, the retaining magnet 7 and the driving magnet 15 are positioned point-symmetrically with respect to the center of the optical glass 2.

[0039] The magnetic plate 8 is made of a magnetic metallic material. The magnetic plate 8 is formed in a flat shape. Specifically, the magnetic plate 8 is formed in an elongated rectangular shape. The thickness of the magnetic plate 8 is thin. For example, the thickness of the magnetic plate 8 is about 0.1 to 0.2 mm. The magnetic plate 8 is arranged so that its thickness direction and left-right direction coincide. Also, the magnetic plate 8 is arranged so that the long side direction of the rectangular flat shape of the magnetic plate 8 coincides with the front-to-back direction. The magnetic plate 8 is placed in the magnetic plate placement hole 4e and fixed within the magnetic plate placement hole 4e. That is, the magnetic plate 8 is fixed to the fixing body 4. The magnetic plate 8 is fixed to the fixing body 4 with adhesive. In this embodiment, the position of the magnetic plate 8 in the vertical direction is adjusted before fixing the magnetic plate 8 to the fixing body 4.

[0040] The magnetic plate 9 is constructed similarly to the magnetic plate 8. The magnetic plate 9 is positioned so that its thickness direction and left-right direction coincide. Furthermore, the magnetic plate 9 is positioned so that its long side direction and front-to-back direction coincide. The magnetic plate 9 is placed in the magnetic plate placement recess 4b. The magnetic plate 9 is placed on the magnetic plate mounting section 4c, and the lower end surface of the magnetic plate 9 is in contact with the upper surface of the magnetic plate mounting section 4c. In other words, the magnetic plate 9 is positioned in the vertical direction. The magnetic plate 9 is also fixed to the flexible printed circuit board 17 and fixed to the fixing body 4 via the flexible printed circuit board 17.

[0041] The magnetic plate 8 is positioned to the left of the retaining magnet 7, and the magnetic plate 9 is positioned to the right of the driving magnet 15. In this embodiment, when the driving coil 16 is not energized, a magnetic attractive force is generated between the magnetic plate 8 and the retaining magnet 7, and between the magnetic plate 9 and the driving magnet 15, to hold the movable body 3 in a fixed position in the direction of rotation of the movable body. Specifically, when the driving coil 16 is not energized, a magnetic attractive force is generated between the magnetic plate 8 and the retaining magnet 7, and between the magnetic plate 9 and the driving magnet 15, to hold the movable body 3 in a reference position in the direction of rotation of the movable body.

[0042] Furthermore, in this embodiment, the position of the movable body 3 in the direction of rotation of the movable body when the drive coil 16 is not energized can be adjusted by adjusting the position of the magnetic plate 8 in the vertical direction. In other words, in this embodiment, the position of the movable body 3 in the direction of rotation of the movable body when the drive coil 16 is not energized is determined by the vertical position of the magnetic plate 8.

[0043] (Structure of the pivot point and the surrounding area of ​​the pivot point) Figure 4(A) is a cross-sectional view of the EE section of Figure 2, and Figure 4(B) is a cross-sectional view of the FF section of Figure 2. Figure 5 is an enlarged view of the sphere 11, sphere holding member 12, and leaf spring 13 shown in Figure 3. Figure 6 is an enlarged view illustrating the configuration of section G in Figure 2.

[0044] As described above, the pivot point 6 comprises a sphere 11, a sphere holding member 12, and a leaf spring 13. The sphere 11 is made of ceramics. For example, the sphere 11 is made of zirconia. The sphere holding member 12 is made of a metal material. The sphere holding member 12 is formed as a bottomed cylinder having a cylindrical portion 12a and a bottom portion 12b connected to one end of the cylindrical portion 12a. Specifically, the cylindrical portion 12a is formed in a cylindrical shape, and the sphere holding member 12 is formed as a bottomed cylinder. The inner diameter of the cylindrical portion 12a is larger than the outer diameter of the sphere 11.

[0045] The sphere holding member 12 is attached to the movable body 3. Specifically, the sphere holding member 12 is fixed to the projection 3c of the movable body 3. The projection 3c is inserted into the cylindrical portion 12a. The projection 3c is also lightly press-fitted into the inner circumference of the cylindrical portion 12a from the inside in the first orthogonal direction. The sphere holding member 12 is fixed to the projection 3c with adhesive. The sphere 11 is positioned on the inner circumference of the cylindrical portion 12a. The bottom portion 12b is positioned outside the tip surface of the projection 3c in the first orthogonal direction. A gap is formed between the tip surface of the projection 3c and the bottom portion 12b for positioning the sphere 11.

[0046] A through-hole 12c is formed in the bottom portion 12b to position a portion of the sphere 11, which is located on the inner circumference side of the cylindrical portion 12a, outside the sphere holding member 12. The through-hole 12c is formed in the center of the bottom portion 12b. Furthermore, the through-hole 12c is formed in a circular shape. Therefore, the bottom portion 12b is formed in an annular shape. The inner diameter of the through-hole 12c is smaller than the outer diameter of the sphere 11. As described above, the sphere 11 is located on the inner circumference side of the cylindrical portion 12a. The sphere 11 is in contact with the bottom surface of the recess 3d and also in contact with the edge of the through-hole 12c. A portion of the sphere 11 is located outside the bottom portion 12b in the first orthogonal direction. That is, a portion of the sphere 11 is located outside the sphere holding member 12. The sphere 11 is held by the movable body 3 by the projection 3c and the sphere holding member 12.

[0047] The leaf spring 13 is formed by bending a metal plate, such as a stainless steel plate, which has spring properties, into a predetermined shape. The leaf spring 13 in this embodiment is formed in a U shape and consists of a first flat plate portion 13b and a second flat plate portion 13c, which are formed in a flat plate shape, and a curved plate portion 13d that connects one end of the first flat plate portion 13b and one end of the second flat plate portion 13c. The leaf spring 13 is arranged in the spring arrangement portion 4d such that the shape of the leaf spring 13 when viewed from the top and bottom is U-shaped. That is, the shape of the leaf spring 13 when viewed from the top and bottom is U-shaped. Also, as described above, since the thickness direction of the optical glass 2 is almost the same as the top and bottom direction, the shape of the leaf spring 13 when viewed from the thickness direction of the optical glass 2 is also U-shaped.

[0048] The first flat plate portion 13b is positioned such that its thickness direction coincides with the first orthogonal direction, and the second flat plate portion 13c is positioned such that its thickness direction coincides with the first orthogonal direction. The first flat plate portion 13b is positioned further outward than the second flat plate portion 13c in the first orthogonal direction. In the leaf spring 13 positioned in the spring arrangement portion 4d at the right rear corner of the fixed body 4, the right front end of the first flat plate portion 13b and the right front end of the second flat plate portion 13c are connected by the curved plate portion 13d. In the leaf spring 13 positioned in the spring arrangement portion 4d at the left front corner of the fixed body 4, the left rear end of the first flat plate portion 13b and the left rear end of the second flat plate portion 13c are connected by the curved plate portion 13d.

[0049] When viewed from the thickness direction of the optical glass 2, the leaf spring 13 positioned at the right rear end and the leaf spring 13 positioned at the left front end are positioned point-symmetrically with respect to the center of the optical glass 2. The leaf springs 13 are fixed to the spring mounting section 4d in a positioned state. That is, the leaf springs 13 are attached to the fixing body 4. Furthermore, the leaf springs 13 are fixed to the spring mounting section 4d with adhesive.

[0050] The tip of the first flat plate portion 13b has the aforementioned contact surface 13a. The contact surface 13a is a concave curved surface that is recessed outward in the first orthogonal direction. The second flat plate portion 13c has a through hole 13e through which the sphere holding member 12 is inserted. The inner diameter of the through hole 13e is larger than the outer diameter of the sphere holding member 12. Reinforcement portions 13f are formed at both the upper and lower ends of the portion of the second flat plate portion 13c in which the through hole 13e is formed, in order to ensure the strength of this portion. The reinforcement portions 13f extend slightly outward in the first orthogonal direction from both the upper and lower ends of the second flat plate portion 13c.

[0051] The contact surface 13a contacts a portion of the sphere 11, which is positioned outside the sphere holding member 12, from the outside in the first orthogonal direction with a predetermined contact pressure. The leaf spring 13 biases the sphere 11 toward the inside in the first orthogonal direction. When the leaf spring 13 is positioned in the spring arrangement section 4d, the sphere holding member 12, which is fixed to the movable body 3, is inserted through the through hole 13e.

[0052] (Main effects of this form) As described above, in this embodiment, the pivot point 6 is equipped with a ceramic sphere 11. Therefore, in this embodiment, even when the optical glass 2 vibrates continuously at a relatively high frequency, the durability of the pivot point 6 can be increased. Furthermore, in this embodiment, the sphere holding member 12 is formed in the shape of a bottomed cylinder having a cylindrical portion 12a on which the sphere 11 is positioned on the inner circumference side and a bottom portion 12b connected to one end of the cylindrical portion 12a. A through hole 12c is formed in the bottom portion 12b to allow a part of the sphere 11 to be positioned outside the sphere holding member 12. Therefore, in this embodiment, even if the sphere 11 is made of ceramic, and even if the outer diameter of the sphere 11 is small, it is possible to easily attach the sphere 11, in which a part of the sphere 11 contacts the contact surface 13a of the leaf spring 13 outside the sphere holding member 12, to the movable body 3 using the sphere holding member 12.

[0053] In this embodiment, a recess 3d is formed on the tip surface of the projection 3c of the movable body 3, in which a part of the sphere 11 is positioned. Therefore, in this embodiment, the state of the sphere 11 held by the movable body 3 can be stabilized by the projection 3c and the sphere holding member 12. In addition, in this embodiment, since the sphere holding member 12 fixed to the movable body 3 is inserted through the through hole 13e of the leaf spring 13 fixed to the fixed body 4, it is possible to prevent the movable body 3 from coming off the fixed body 4 either upward or downward.

[0054] (Example of leaf spring modification) Figure 7 is a diagram of a leaf spring 23 according to another embodiment of the present invention, where (A) is a plan view and (B) is a perspective view. Figure 8 is a plan view illustrating the configuration of the pivot point 6 according to another embodiment of the present invention. Figure 9 is an enlarged view of section J in Figure 7(B).

[0055] In the above-described configuration, two separately formed leaf springs 13 are arranged on both ends of the movable body 3 in the first orthogonal direction. However, the actuator 1 may be equipped with a single leaf spring 23 instead of the two leaf springs 13. The leaf spring 23 is formed by bending a metal plate, such as a stainless steel plate, which has spring properties, into a predetermined shape. The thickness of the leaf spring 23 is, for example, 0.2 mm. The leaf spring 23 comprises a spring portion 23b as a spherical support member arranged on each end of the movable body 3 in the first orthogonal direction, and a flat plate-shaped connecting portion 23c that connects the two spring portions 23b. In this modified example, the leaf spring 23 is composed of two spring portions 23b and a connecting portion 23c.

[0056] The connecting portion 23c is formed in a frame shape. Specifically, the connecting portion 23c is formed in a roughly square or roughly rectangular frame shape. The connecting portion 23c is fixed to the upper end surface of the fixed body 4, which is formed in a frame shape. That is, the connecting portion 23c is fixed to one side of the fixed body 4 in the thickness direction of the optical glass 2. As shown in Figure 3, etc., the upper end surface of the fixed body 4 is a plane perpendicular to the vertical direction. The connecting portion 23c is fixed to the upper end surface of the fixed body 4 such that the thickness direction of the flat connecting portion 23c coincides with the vertical direction. The connecting portion 23c is also fixed to the upper end surface of the fixed body 4 with adhesive.

[0057] Two of the four sides constituting the outer periphery of the connecting portion 23c, which has an outer shape that is roughly square or rectangular, are parallel to the left-right direction, and the remaining two sides are parallel to the front-back direction. A portion of the inner periphery of the frame-shaped connecting portion 23c overlaps in the vertical direction with a portion of the outer periphery of the frame-shaped movable body 3. The connecting portion 23c also serves to restrict the upward movement range of the movable body 3 relative to the fixed body 4. The fixed body 4 has a restricting portion formed therein that restricts the downward movement range of the movable body 3 relative to the fixed body 4.

[0058] The spring portion 23b is connected to each of the ends of the connecting portion 23c in the first orthogonal direction. The spring portion 23b is formed in a flat plate shape. The spring portion 23b is positioned such that its thickness direction coincides with the first orthogonal direction. The spring portion 23b is positioned below the connecting portion 23c. That is, both ends of the leaf spring 23 in the first orthogonal direction are bent at a right angle downwards. At the right rear corner of the connecting portion 23c, the right front end of the spring portion 23b that forms the base end of one spring portion 23b is connected to the connecting portion 23c, and at the left front corner of the connecting portion 23c, the left rear end of the spring portion 23b that forms the base end of the other spring portion 23b is connected to the connecting portion 23c.

[0059] When viewed from the thickness direction of the optical glass 2, the two spring portions 23b are arranged point-symmetrically with respect to the center of the optical glass 2. As described above, the connecting portion 23c is fixed to the upper end surface of the fixed body 4. That is, the two spring portions 23b, which are integrally formed with the connecting portion 23c, are attached to the fixed body 4 via the connecting portion 23c.

[0060] A contact surface 23a corresponding to the contact surface 13a of the leaf spring 13 is formed at the tip of the spring portion 23b (see Figure 7(B)). That is, the spring portion 23b has a concave curved contact surface 23a that contacts a part of the sphere 11 with a predetermined contact pressure. The contact surface 23a is a concave curved surface that is recessed outward in the first orthogonal direction. The contact surface 23a contacts a part of the sphere 11, which is located outside the sphere holding member 12, from the outside in the first orthogonal direction with a predetermined contact pressure. The spring portion 23b biases the sphere 11 inward in the first orthogonal direction. In this modified example, the pivot point 6 is composed of the sphere 11, the sphere holding member 12, and the spring portion 23b.

[0061] The spring portion 23b has a reinforcing rib 23d formed thereon. The rib 23d is formed by drawing a portion of the spring portion 23b. The rib 23d protrudes outward in the first orthogonal direction. When viewed from the first orthogonal direction, the shape of the rib 23d is L-shaped.

[0062] In this modified example, since the two spring sections 23b are integrated via the connecting section 23c, it is possible to reduce the number of parts in the actuator 1 compared to the configuration described above, where two separate leaf springs 13 are provided. Furthermore, in this modified example, since the two spring sections 23b are attached to the fixed body 4 by fixing the connecting section 23c to the fixed body 4, it is possible to reduce the assembly man-hours for the actuator 1 compared to the configuration described above, where each of the two separate leaf springs 13 is fixed to the fixed body 4.

[0063] Furthermore, in this modified example, the two spring portions 23b are attached to the fixed body 4 by adhesively fixing the frame-shaped connecting portion 23c to the frame-shaped fixed body 4. This ensures sufficient adhesive area for the connecting portion 23c to the fixed body 4, thereby increasing the mounting strength of the spring portions 23b to the fixed body 4. Also, in this modified example, the two spring portions 23b are integrated via the connecting portion 23c, and the variation in the relative positions of the two spring portions 23b is determined by the component precision of the leaf spring 23. Therefore, compared to the above-described configuration where each of the two separately formed leaf springs 13 is fixed to the fixed body 4, it is possible to suppress variations in the relative positions of the two contact surfaces 23a.

[0064] Furthermore, in this modified example, since reinforcing ribs 23d are formed on the spring portion 23b, it becomes possible to ensure the strength of the spring portion 23b even if the thickness of the leaf spring 23 is reduced. However, if the strength of the spring portion 23b can be ensured, it is not necessary for the ribs 23d to be formed on the spring portion 23b.

[0065] (Other embodiments) The above-described embodiment is merely one example of a preferred embodiment of the present invention, and is not limited thereto. Various modifications can be made without altering the essence of the present invention.

[0066] In the above-described configuration, the leaf spring 13 may be arranged in the spring arrangement section 4d such that the curved plate portion 13d becomes the lower end of the leaf spring 13. That is, the lower end of the first flat plate portion 13b and the lower end of the second flat plate portion 13c are connected by the curved plate portion 13d, and the shape of the leaf spring 13 when viewed from the front right (or rear left) may be U-shaped. However, as in the above-described configuration, if the leaf spring 13 is arranged in the spring arrangement section 4d such that the shape of the leaf spring 13 when viewed from the up and down direction is U-shaped, it becomes possible to miniaturize the leaf spring 13 in the up and down direction, and therefore it becomes possible to miniaturize the actuator 1 in the up and down direction.

[0067] In the above-described configuration, the leaf spring 13 may be attached to the movable body 3, and the sphere holding member 12 may be attached to the fixed body 4. In this case, the sphere 11 is held by the fixed body 4. In this case, the contact surface 13a of the leaf spring 13 contacts a portion of the sphere 11 exposed to the outside of the sphere holding member 12 from the inside in a first orthogonal direction with a predetermined contact pressure. In the above-described modified example, the connecting portion 23c of the leaf spring 23 may be fixed to the movable body 3, and the sphere holding member 12 may be attached to the fixed body 4. In this case, the contact surface 23a of the leaf spring 23 contacts a portion of the sphere 11 exposed to the outside of the sphere holding member 12 from the inside in a first orthogonal direction with a predetermined contact pressure.

[0068] In the above-described embodiment, the actuator 1 may be mounted and used in a device other than a projector. In this case, optical elements other than the optical glass 2 may be held by the movable body 3. For example, optical elements such as lenses, prisms, reflectors, or optical filters may be held by the movable body 3. Also, an image sensor may be held by the movable body 3. When an image sensor is held by the movable body 3, the actuator 1 is mounted, for example, in a camera. The term "optical element" in this specification also includes an image sensor. [Explanation of Symbols]

[0069] 1 Actuator 2. Optical glass (optical elements) 3 Movable body 3c protrusion 3D recess 4 Fixed body 5 Magnetic drive mechanism 6. Support point 11 Spheres 12 Sphere holding member 12a Cylinder part 12b bottom 12c through hole 13. Leaf spring (spherical support member) 13a Contact surface 23 Leaf spring 23a Contact surface 23b Spring section (spherical support member) 23c Connecting part 23d Rib V First orthogonal direction

Claims

1. The device comprises a movable body for holding an optical element, a fixed body formed in the shape of a frame and positioned on the inner circumference side of the movable body, which rotatably holds the movable body, a magnetic drive mechanism for rotating the movable body in a direction that causes the movable body to tilt relative to the fixed body, and a pivot point that serves as the pivot point for the rotation of the movable body relative to the fixed body. The pivot point comprises a ceramic sphere, a sphere holding member attached to either the movable body or the fixed body for holding the sphere, and a sphere support member having a concave curved contact surface that contacts a part of the sphere with a predetermined contact pressure and attached to the other of the movable body or the fixed body. The sphere-holding member is formed in a bottomed cylindrical shape, having a cylindrical portion formed in a tubular shape and a bottom portion connected to one end of the cylindrical portion. The sphere is positioned on the inner circumference side of the cylindrical portion. A through hole is formed in the bottom portion to allow a portion of the sphere, which is positioned on the inner circumference of the cylindrical portion, to be positioned outside the sphere holding member. The actuator is characterized in that the contact surface is in contact with a part of the sphere that is located outside the sphere holding member.

2. The optical element is formed in the shape of a flat plate, The actuator according to claim 1, characterized in that the pivot point is located on both ends of the movable body in a first orthogonal direction perpendicular to the thickness direction of the optical element.

3. The sphere-holding member is attached to the movable body. The spherical support member is attached to the fixed body. The movable body has projections that protrude toward both sides in the first orthogonal direction and are inserted into the cylindrical portion. A recess is formed on the tip surface of the projection, in which a part of the sphere is positioned. The actuator according to claim 2, characterized in that the contact surface is in contact with a part of the sphere from the outside in the first orthogonal direction.

4. The aforementioned spherical support member is a leaf spring formed in a U shape. The actuator according to claim 2 or 3, characterized in that the shape of the leaf spring when viewed from the thickness direction of the optical element is U-shaped.

5. The device comprises a leaf spring having spherical support members positioned at each end of the movable body in the first orthogonal direction, and a flat plate-shaped connecting portion connecting the two spherical support members, The actuator according to claim 2 or 3, characterized in that the connecting portion is formed in a frame shape and is fixed to one side of the movable body or the fixed body in the thickness direction of the optical element.

6. The actuator according to claim 5, characterized in that the spherical support member has reinforcing ribs formed thereon.

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