JP3462684B2 - Optical deflection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical deflecting device for deflecting a light beam, which is used as a constituent element of an optical system for recording and reproducing optical information on a magneto-optical disc or an optical disc, for example. To obtain an optical deflection device.

[0002]

2. Description of the Related Art A galvanometer mirror device is known as a typical one of the above-mentioned optical deflecting devices, and an optical deflecting device of this kind is described, for example, in Japanese Utility Model Publication No. 7-28585. The optical deflecting device disclosed in this publication includes a base body and a movable portion held by the base body via a leaf spring element. The movable part consists of an electromagnetic coil adapted to cooperate with a permanent magnet provided in the base body, to which an optical element for deflecting the light beam is associated, for example a mirror, the leaf spring element of which has a longitudinal axis. Are arranged so as to substantially pass through the center of gravity of the movable part.

The electromagnetic coil is arranged in a magnetic field obtained by a permanent magnet on the base body side, and when the electromagnetic coil is energized at this time, the movable part rotates around the longitudinal axis of the leaf spring according to Fleming's left-hand rule. It receives power, and the amount of rotation thereof depends on the amount of electricity supplied to the electromagnetic coil. Thus, in the optical deflecting device as described above, the light beam incident on the optical element for deflecting the light beam of the movable portion is controlled within the predetermined deflection range by appropriately controlling the energization amount to the electromagnetic coil of the movable portion. It becomes possible to deflect in a desired direction.

[0004]

[Problems to be Solved by the Invention]
In the optical deflecting device disclosed in the publication, since the movable part is supported by only a single leaf spring element, the leaf spring exhibits low compliance in the direction perpendicular to its plane. Therefore, when such a conventional optical deflecting device receives an external force such as an external vibration, a structurally coupled vibration or a thrust-coupled vibration is generated in the movable part, which prevents the mirror from maintaining a normal posture. However, there is a problem that inconvenience such as dynamic crosstalk occurs.

On the other hand, Japanese Patent Publication No. 3-49409 also discloses an optical deflecting device as described above. In this optical deflecting device, a pair of strip-shaped leaf springs are formed in a cross shape on both sides of the rotation axis of the movable part. The movable portion is supported by the base body via the cross spring. That is, the rotation axis of the movable portion is supported so as to be defined by the intersection of the pair of cross leaf springs on each side thereof. However, since the fixing point of the strip-shaped leaf spring to the base body side and the fixing point to the movable part side are located off the rotation axis of the movable part, a pair of crosses on each side of the rotation axis of the movable part is formed. The position of the intersection of the leaf springs is likely to change when an external force such as an external vibration is applied, so that there is a problem that such a movable portion is easily subjected to the structural coupled vibration and the thrust coupled vibration.

Further, in the optical deflecting device disclosed in Japanese Patent Publication No. 3-49409, the precision of each component when mounting the component such as the movable part and the cross leaf spring to the base body is structured. It is also pointed out that it is difficult. Further, in such an optical deflecting device, a block-shaped mounting seat is required on the outer peripheral side of the movable portion for mounting the cross-shaped leaf spring, and the moment of inertia increases due to the additional mass of the mounting portion, which increases the movable portion. That is, there is a problem that the movement sensitivity of the mirror is lowered.

Therefore, an object of the present invention is an optical deflecting device of the type described above, which is constructed so as to eliminate structurally coupled vibration and thrust coupled vibration as much as possible. Is to provide.

[0008]

An optical deflecting device according to the present invention comprises a light beam deflecting means for pivotally supporting a movable part with respect to a base body through elastic means and for deflecting a light beam to the movable part. are those formed by mounted, according to the present invention, in such an optical deflection device, Ri consists of at least three plates spring element has resilient means equally spaced around the elastic principal axis of the movable portion , The elastic main axis of the movable part
Is substantially aligned with the principal axis of inertia of the movable part, and
The feature is that the thrust main axis of the movable part can be substantially matched.
To collect .

[0009]

In the optical deflector according to the invention, all of the leaf spring elements can be of the same form. When the elastic spring element is composed of at least four even-numbered leaf spring elements, two leaf spring elements of the even-numbered leaf spring elements which are arranged in the same plane and are arranged in the diameter direction. May have the same form.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an optical deflecting device according to the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 1, an embodiment of an optical deflector according to the present invention is illustrated in exploded perspective view, the optical device being formed from a suitable metallic material such as aluminum or its alloys or a suitable hard synthetic resin material. The base body 10 includes a base portion 10A and a frame portion 10B which is integrally upright from the base portion 10A. The base body 10 functions as a mounting portion when the optical deflecting device is incorporated as a component of the optical system. The frame portion 10B has a circular opening 10
It has an annular shape that defines C. Further, the optical deflecting device according to the present invention comprises a movable part 12, and the movable part 1
2 has the form of a short cylinder. The movable portion 12 is arranged in the circular opening 10C of the frame portion 10B, and is supported by the frame portion 10B of the base body 10 via elastic means as described in detail later.

A substantially rectangular cover member 14 is appropriately mounted on the front side of the base body 10, and a circular opening 14A is formed in the center of the cover member 14. On the other hand, a permanent magnet holder member 16 is appropriately mounted on the rear side of the base body 10. The permanent magnet holder member 16 has a holder portion 16A having a short cylindrical shape, and a diameter integrally formed from the holder portion 16A. It is composed of a pair of mounting plates 16B projecting in the direction. Two pairs of segment-shaped permanent magnets 18 and 20 are housed in the holder portion 16A, and the pair of segment-shaped permanent magnets 18 and 20 are arranged such that different poles face each other. In FIG. 1, a pair of segment-shaped permanent magnets 20
Only one can see.

The pair of mounting plates 16B are used to mount the permanent magnet holder member 16 on the frame portion 10B of the base body 10, and the holder member 16A is housed in the circular opening 10C of the frame portion 10 when mounted. And is arranged so as to cover the periphery of the two pairs of segment-shaped permanent magnets 18 and 20. The cover member 14 and the holder member 1
6 is preferably formed of the same material as the base body 10.

Referring to FIG. 2, the movable part 12 is shown in an enlarged exploded perspective view, and the movable part 12 has an optical deflection element holder member 12A having a shape of a short cylinder, and this optical deflection element holder. And a prism 12B mounted inside the member 12A. In this embodiment, the prism 12B is used as the optical deflecting element, but other optical deflecting elements include, for example, a light reflecting mirror and a light beam deflecting hologram.

As shown in FIG. 2, the holder member 12A for the optical deflecting element has a central flange portion 12A having a polygonal shape.
₁ and collar portions 12A ₂ and 12A ₃ protruding from both sides of the central flange portion 12A ₁ . Movable part 12
Further includes the collar portions 12A ₂ and 1 of the optical holder member 12A.
Electromagnetic coils 12C and 1 attached to each of 2A ₃
2D, and these electromagnetic coils 12C and 12D include two pairs of segment type permanent magnets 18 and 20 as will be described later.
And functions as a drive mechanism for driving the movable portion 12 in cooperation with. In FIG. 2, the electromagnetic coils 12C and 1
2D is shown as an annular ring type, but each electromagnetic coil 12C, 12D is obtained by winding a conductive wire in such an annular ring shape, and the feeding lines to these electromagnetic coils 12C, 12D are not shown. It is omitted.

The movable portion 12 further includes leaf spring couplings 12E attached to both sides of the central flange portion 12A ₁ of the optical deflection element holder member 12A in the diametrical direction. In addition, in FIG. 2, the coupling 1 for the leaf spring on one side is shown.
Although only 2E is shown, a similar leaf spring coupling is also provided diametrically opposite the central flange portion 12A ₁ . The leaf spring coupling 12E includes a fixed coupling portion 12E ₁ which is fixed to the central flange portion 12A ₁ and a movable coupling portion 12E _{2 which} is detachable from the fixed coupling portion 12E ₁ . Consists of.

A composite leaf spring body 22 is connected to each leaf spring coupling 12E, and the composite leaf spring body 22 is composed of four leaf spring elements 22A in this embodiment. Figure 3
As shown in detail in this embodiment, in the present embodiment, the H-shaped leaf spring material is provided with the slits 24 in such a manner as to divide the H-shaped leaf spring material in half so that the H-shaped leaf spring material is provided with the pair of leaf spring elements 22A. It is formed. By combining two such H-shaped leaf spring materials along their slits 24, a composite leaf spring body 22 as shown in FIG. 2 is obtained,
At this time, in the composite leaf spring body 22, four leaf spring elements 22A are arranged at equal intervals at an angle of 90 degrees around the longitudinal center axis of the slit 24.

As shown in FIG. 2, another leaf spring coupling 26 is provided on the opposite side of the leaf spring coupling 12E.
Fixed coupling portion 26 ₁ which is fixed to the frame portion 10B of 0, and this fixed coupling portion 26 ₁
It is composed of a movable coupling portion 26 ₂ which can be freely attached to and detached from. The configuration of the leaf spring coupling 26 is such that the fixed coupling portion 26 ₁ is a mounting block piece 28 having a through hole.
The structure is the same as that of the above-mentioned leaf spring coupling 12E except that it is integrated with.

As shown in more detail in FIG. 4, the fixed coupling portion 26 ₁ is formed as a tubular short shaft member 26A which integrally projects from the mounting block piece 28, and the free end surface of the tubular short shaft member 26A is The four claw elements 26B project. The four claw elements 26B are arranged at equal intervals along the circumferential direction of the tubular short shaft member 26A at an angle of 90 degrees, and the cross section of each claw element 26A has a segment shape as shown in the drawing. A pair of flat surfaces 26C facing each other in the diametrical direction are formed on the lateral sides of the tubular short shaft member 26A. Note that in FIG. 4, only one of the pair of flat surfaces 26C can be seen.

Meanwhile, it is also movable coupling portion 26 ₂ is formed as a tubular minor axis member 26D, the diameter of which is larger than the tubular minor axis member 26A, the tubular short axis member 26A is fitted loosely in a tubular minor axis member 26D Are ready to go together. Similar to the case of the tubular short shaft member 26A, the tubular short shaft member 26D
Four claw elements 26E project from one free end surface of
These four claw elements 26E are arranged at equal intervals along the circumferential direction of the tubular short shaft member 26D at an angle of 90 degrees, and the cross section of each claw element 26E has a segment shape as shown in the drawing. As is clear from FIG. 5, the tubular short shaft member 26D
In the lateral portion of the pair, two flat surfaces 26F and 26G facing each other in the diametrical direction are formed. Note that in FIG. 4, only one of each of the two pairs of flat surfaces 26F and 26G can be seen.

As shown in FIG. 5, two pairs of flat surfaces 26F and 26G formed on the tubular short shaft member 26D are provided with screw holes 26H and 26I, respectively.
6H and 26I are displaced in the opposite direction to the longitudinal center axis of the tubular short shaft member 26D to be eccentric. That is,
In the example shown in FIGS. 4 and 5, the screw hole 26H formed in the flat surface 26F visible in FIG.
A screw formed on a flat surface 26F (FIG. 5) that is displaced counterclockwise when viewed from the side of the four claw elements 26E of 6D, and is diametrically opposite to the flat surface 26F. The hole 26H is also displaced in the counterclockwise direction. As is clear from FIG. 5, the same can be said for the pair of screw holes 26I formed in the other pair of flat surfaces 26G as the pair of screw holes 26H described above.

Therefore, the movable coupling portion 26 ₂ is attached to the fixed coupling portion 26 ₁ , and both claw elements 26B are attached.
And 26E are engaged with each other in the manner shown in FIG. 5, respectively, and then the pair of setscrew elements 30 (FIG. 4) are screwed into, for example, a pair of screw holes 26H.
Is the flat surface 26C of the fixed coupling portion 26 _1.
Abutting against and further screwing in the set screw element 30, both the movable coupling portion 26 ₂ and the fixed coupling portion 26 ₁ receive rotational forces in opposite directions, which causes the pawl elements 26B and 26E to engage each other. The surfaces are acted against each other. Claw elements 26B and 2
Each leaf spring element 2 of the composite leaf spring body 22 is provided between each of the 6Es.
By performing the screwing operation of the pair of setscrew elements 30 as described above with the corresponding end portion of 2A being sandwiched,
The composite leaf spring body 22 is fixedly connected to a leaf spring coupling 26.

As described above, the configuration of the leaf spring coupling 26 is the same as that of the leaf spring coupling 12E, and the composite leaf spring body 22 is similar to the leaf spring coupling 12E in the same manner. It is fixedly connected.

FIG. 1 shows the movable part 12 in an assembled state. At this time, a pair of leaf spring couplings 12E is used.
One end side of the composite leaf spring body 22 is fixedly connected to each of the above, and a leaf spring coupling 26 is fixedly connected to the other end side of the composite leaf spring body 22. The bolt element 32 is inserted into the through hole of the mounting block piece 28 of the fixed coupling portion 26 ₂ of each leaf spring coupling 26,
Each bolt element 32 further includes a frame 10 of the base body 10.
It is screwed into a screw hole 10D formed in the diametrical direction of B.
As is clear from FIG. 1, the screw holes 10D are arranged in the recesses formed in the frame portion 10B, and the bolt elements 3 are
When the mounting block piece 28 is screwed by 2, the mounting block piece 28 is accommodated in the recess.

Thus, the movable portion 12 is supported by the frame portion 10B of the base body 10 through the pair of composite leaf spring bodies 22, and at this time, the movable portion 12 is long in the lengths of the leaf spring couplings 12E and 26. It is most easily moved around the central axis in the direction, that is, the central axis in the longitudinal direction of the composite leaf spring 22. More specifically, as shown in FIG. 6, the composite leaf spring body 22
A three-dimensional coordinate system having the center of the origin as the origin is set, and at this time, one pair of leaf spring elements 22A is positioned in the XZ plane,
If the other pair of leaf spring elements 22A is located in the YZ plane, the compliance around the X axis (α) and the Y
The compliance around the axis (β) is substantially the same as each other, and is much larger than the compliance around the Z axis (γ). In short, in the configuration of the composite leaf spring body 22 as shown in the figure, the low compliance is obtained only around the Z axis (γ).

On the other hand, when the electromagnetic coils 12C and 12D of the movable portion 12 are energized in the magnetic field obtained by the two pairs of segment-shaped permanent magnets 18 and 20, the movable portion 12 moves around the Z axis according to Fleming's left-hand rule. The rotational direction depends on the energization direction to the electromagnetic coils 12C and 12D. In short, the Z axis serves as the rotation axis of the movable portion 12, that is, the elastic main axis.

According to the arrangement configuration of the composite leaf spring body 22 as described above, low compliance can be given only around the elastic main axis (Z axis) of the movable portion 12, so that when the movable portion 12 is driven, external compliance is provided. Even if an external force such as a vibration is applied to the optical deflecting device, the movable portion 12 has the elastic main axis (Z
It can rotate stably only around the axis.

Preferably, the center of gravity of the movable portion 12 is located substantially on its elastic main axis (Z axis).
The total mass balance of 2 is considered. That is, the movable part 1
It is preferable that the elastic main axis (Z axis) of 2 substantially coincides with the principal axis of inertia of the movable part 12, and in this case, the occurrence of structurally coupled vibration in the movable part 12 is effectively eliminated. Is possible.

Further, it is preferable that the movable part 12 is substantially positioned so that the center of rotation when the movable part 12 receives a turning force when the electromagnetic coils 12C and 12D are energized is located on the elastic main axis (Z axis). A total mass balance of 12 is considered.
That is, the elastic main axis (Z axis) of the movable portion 12 is
It is preferable to substantially coincide with the thrust main axis line of No. 1, and in this case, it is possible to effectively eliminate the occurrence of thrust-coupling vibration in the movable portion 12.

More preferably, the elastic main axis (Z axis), the inertia main axis and the thrust main axis of the movable part 12 are made to substantially coincide with each other. It is possible to effectively eliminate the generation of both the generated vibration and the thrust coupled vibration.

Referring to FIG. 7, another embodiment of a leaf spring coupling (12E, 26) is shown, generally designated by the reference numeral 34. The leaf spring coupling 34 comprises a fixed coupling portion 34 ₁ and a movable coupling portion 34 ₂ . In the example shown in FIG. 7, the fixed coupling portion 34 ₁ includes a male screw portion 34A integrated with the mounting block piece 28, and four claw pieces 34B protruding from the end surface of the male screw portion 34A in a cantilever manner. And these claw pieces 34B form a chuck with a cruciform slit. As is apparent from FIG. 7, each claw piece 34
A tapered surface is formed on the outer periphery of the tip side of B over a range of about 90 degrees. When the leaf spring coupling 34 is used in place of the leaf spring coupling 12E described above, the male screw portion 34A is fixed to the central flange portion 12A ₁ of the optical deflection element holder member 12A of the movable portion 12. Needless to say.

On the other hand, the movable coupling portion 34 ₂ of the leaf spring coupling 34 is constructed as a sleeve-shaped member 34C, and the tip end side of the sleeve-shaped member 34C is tapered surface 3.
It is formed as 4D. A female screw portion that can be screwed into the male screw portion 34A is formed on the inner side surface of the sleeve member 34C, and the tip side of the inner side surface is also a tapered surface corresponding to the tapered surface 34D. The size of the end opening of the sleeve member 34C on the side of the tapered surface 34D is set so that the composite leaf spring body 22 can be inserted therethrough.

The one end side of the composite leaf spring body 22 is inserted into the end opening of the sleeve-shaped member 34C, and four claw pieces 34 are formed.
When the sleeve-shaped member 34C is screwed into the male screw portion 34A after being inserted into the cross-shaped slit formed by B, the inner tapered surface of the sleeve-shaped member 34C is engaged with the tapered surfaces of the four claw pieces 34B. The claw piece 34B is biased by the wedge action so as to close the cross slit,
As a result, the composite leaf spring body 22 becomes the leaf spring coupling 3
4 is fixedly connected.

In the embodiment described above, the composite leaf spring body 22 has two H-shaped leaf spring materials having a pair of leaf spring elements 22A in their slits 24 as described with reference to FIG. The composite leaf spring body 22 is obtained by arranging as shown in FIG. 9 by using four single leaf spring elements 22A 'as shown in FIG. Is also possible. The leaf spring couplings (12E, 26, 3) as described above.
If 4) is used, it is easy to arrange the four leaf spring elements 22A 'at equal intervals at an angle of 90 degrees around the longitudinal central axis (Z axis) of the coupling. is there.

A single leaf spring element 22 as shown in FIG.
The advantage of using A'is that the number of leaf spring elements 22A 'constituting the above-mentioned composite leaf spring body can be appropriately changed as necessary. For example, if the leaf spring couplings (12E, 26, 34) as described above are configured to connect the six leaf spring elements 22A 'at an angle of 60 degrees at equal intervals, the configuration shown in FIG. Compound leaf springs such as 6
It is possible to easily obtain a composite leaf spring body in which the leaf spring elements 22A 'are arranged at equal intervals of 60 degrees. Also, the leaf spring couplings (12E, 26, 3
4) is configured to connect eight leaf spring elements 22A 'at equal intervals of 45 degrees, a composite leaf spring body as shown in FIG. 11, that is, eight leaf spring elements 22A' is formed. A composite leaf spring body arranged at equal intervals at an angle of 45 degrees can be easily obtained.

In the embodiments shown in FIGS. 9 to 11, an example is shown in which the composite leaf spring body constitutes an even number of leaf spring elements 22A '. However, in such a composite leaf spring body, three or more leaf spring elements are used. It is also possible to configure by arranging an odd number of leaf spring elements 22A 'at equal intervals.

Further, in the above-mentioned embodiment, the leaf spring elements constituting the composite leaf spring body are all in the same form, but when the composite leaf spring body is composed of four or more even-numbered sheets, If only a pair of leaf spring elements diametrically arranged in the same plane have the same shape, the other leaf spring elements do not necessarily have the same shape.

[0039]

As is apparent from the above description, in the optical deflecting device according to the present invention, since the composite leaf spring body is used which gives the low compliance only around the rotation axis of the movable portion. It is possible to stably rotate the movable portion around its rotation axis, and thus a highly reliable deflection operation of the light beam can be obtained.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an optical deflecting device according to the present invention.

FIG. 2 is an exploded perspective view of a movable portion that is a component of the optical deflecting device shown in FIG.

FIG. 3 is an exploded perspective view of a composite leaf spring body that supports the movable portion shown in FIG.

FIG. 4 is an exploded perspective view of a leaf spring coupling for connecting the composite leaf spring bodies shown in FIG.

5 is an end view of the leaf spring coupling shown in FIG. 4. FIG.

FIG. 6 is an assembled perspective view of the composite leaf spring body shown in FIG. 3, and is an explanatory diagram for explaining its characteristics.

7 is an exploded perspective view showing another embodiment different from the leaf spring coupling shown in FIG. 4. FIG.

FIG. 8 is a perspective view showing a leaf spring element that constitutes a composite leaf spring body.

9 is a perspective view showing an example in which a composite leaf spring body is configured by using the four leaf spring elements shown in FIG.

10 is a perspective view showing an example in which a composite leaf spring body is configured by using the six leaf spring elements shown in FIG.

11 is a perspective view showing an example in which a composite leaf spring body is configured by using eight leaf spring elements shown in FIG.

[Explanation of symbols]

10 base body 10A base portion 10B frame portion 10C circular opening 12 movable portion 12A optical deflector element holder member 12A ₁ central flange portion 12A _2, 12A ₃ Color section 12C, 12D electromagnetic coils 18 and 20 segmented permanent magnet 12E, 26, 34 Leaf spring coupling

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02B 26/10

Claims (3)

(57) [Claims] 1. A optical deflecting device formed by mounting the optical beam deflecting means for deflecting the light beam to the movable portion causes the axially supporting the movable portion through an elastic means against the base body, said elastic means There consisting of at least three plate spring elements disposed at regular intervals around the elastic principal axis of the movable portion, the elastic principal axis of the movable part is substantially matched to the inertial main axis of the movable portion, and together are substantially matched to thrust the main axis of the movable portion, said light beam deflecting means, the optical deflection element and a pair of annular Li
And an electromagnetic coil in the shape of a ring , wherein the movable part has a central flange part and a central flange part.
The optical polarization consisting of a pair of collars protruding from both sides.
A pair of electromagnetic coils are provided so that the pair of electromagnetic coils are coaxial with each other.
An optical deflection device characterized by being attached to each of the collar sections . 2. The optical deflecting device according to claim 1, wherein all of the leaf spring elements have the same shape. 3. The optical deflector according to claim 1, wherein the elastic means is composed of at least four even-numbered leaf spring elements, and the diameters of the even-numbered leaf spring elements that are coplanar with each other. An optical deflecting device in which two leaf spring elements arranged in the same direction have the same shape.