JP2006190482A - Optical path deflection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical path deflection apparatus in which a center of electromagnetic force generated in a coil of a movable part and a center of a rotation of the movable part are easily aligned with each other to make resonance hardly occur at the time of rotation of the movable part, while thinning of the movable part can be attained. <P>SOLUTION: In the optical path deflection apparatus 15 having the movable part 14 having at least an optical element 4 and a coil 10, a plurality of supporting members 12 supporting the movable part 14 rotatably, a base 13 fixing a part of the supporting member 12, and magnetic circuits 16, 17 fixed at the base 13, the coil 10 is arranged so as to surround an outer periphery of the optical element 4, and a fixing part 12a for the movable part 14 of the supporting member 12 is arranged at an outside plane side of the coil 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an information recording / reproducing apparatus for recording and / or reproducing information with respect to an optical recording medium such as a magneto-optical disk drive, a write-once disk drive, a phase change disk drive, a CD-ROM, a DVD, and an optical card. The present invention also relates to an optical path deflecting device (mirror type deflecting device) for controlling the direction of a light beam used in an optical device such as an optical scanner.

  An optical apparatus such as an information recording / reproducing apparatus for recording and / or reproducing information on an optical recording medium such as a magneto-optical disk drive, a write-once disk drive, a phase change disk drive, a CD-ROM, a DVD, or an optical card; In an optical device such as an optical scanner, an optical path deflecting device such as a galvanometer mirror is used to tilt the light beam. As an optical path deflecting device, for example, those shown in a perspective view and a sectional view in FIGS. 10A and 10B are known (see, for example, Patent Document 1).

10A and 10B, the actuator coil 110b is attached to the mirror 110a constituting the movable part 110, the two flexible substrates 120 are provided on the back surface of the mirror 110a, and one end thereof is supported by the fixed part S. Yes. Each flexible substrate 120 is formed by forming a coating material on the surface of a strip-shaped spring plate made of a conductive spring material. The magnet 130 forming the magnetic circuit is fixed so as to face the actuator coil 110b and is magnetized in the direction of the arrow d. These magnets 130 generate an electromagnetic force in the directions of arrows a and b in the actuator coil 110b by an electromagnetic induction effect with the current i. Thereby, when the movable part 110 is rotated, the movable part 110 is rotated about the horizontal axis CC, and the mirror 110a is tilted to control the direction of the light beam.
JP-A-6-349093

  However, in the apparatus disclosed in Patent Document 1, the actuator coil 110b is attached to the side surface of the mirror 110a, and the flexible substrate 120 that is a support member of the movable portion 110 is fixed to the back surface of the mirror 110a. Therefore, the center M of the electromagnetic force in the direction of arrows a and b generated in the actuator coil 110b and the flexible substrate 120 (horizontal axis cc) which is a support member of the movable portion 110 are shifted in the movable portion thickness direction ( FIG. 10B). Then, when the movable part 110 rotates due to the deviation, there arises a problem that resonance that not only rotates around the horizontal axis cc but also moves in other directions is likely to occur. Further, the center M of the electromagnetic force in the direction of arrows a and b generated in the actuator coil 110b and the flexible substrate 120 which is a support member of the movable part 110 are displaced in the thickness direction of the movable part. The problem that it must be thick also arises.

  The present invention has been made paying attention to the above-mentioned drawbacks, and it is easy to make the center of electromagnetic force generated in the coil of the movable part coincide with the center of rotation of the movable part, and as a result, resonance occurs when the movable part rotates. An object of the present invention is to provide an optical path deflecting device that is difficult to perform. It is another object of the present invention to provide an optical path deflecting device in which the movable portion is thinned.

  The invention according to claim 1, which achieves the above object, includes a movable portion having at least an optical element and a coil, a plurality of support members that rotatably support the movable portion, and a base that fixes a part of the support member. And a magnetic circuit fixed to the base, the coil is disposed so as to surround the outer periphery of the optical element, and the support member is connected to the movable portion on the outer surface side of the coil. The fixing portion is arranged.

  According to a second aspect of the present invention, in the optical path deflecting device according to the first aspect, the support member is directly fixed to the outer surface of the coil.

  According to a third aspect of the present invention, there is provided a movable part having at least an optical element and a coil, a plurality of support members for rotatably supporting the movable part, a base for fixing a part of the support member, and the base In the optical path deflecting device having a fixed magnetic circuit, the coil is disposed so as to surround the outer periphery of the optical element, and a bifurcated portion is formed on at least a part of the support member. The movable portion is supported so as to sandwich the coil.

  According to the first aspect of the present invention, a movable part having at least an optical element and a coil, a plurality of support members that rotatably support the movable part, a base that fixes a part of the support member, and An optical path deflecting device having a magnetic circuit fixed to a base, wherein the coil is disposed so as to surround an outer periphery of the optical element, and a fixing portion of the support member to the movable portion is provided on an outer surface side of the coil. Since they are arranged, the rotation axis of the movable part and the center of the force generated in the coil can be easily matched, and good response characteristics with little resonance can be obtained.

  According to the invention according to claim 2, in the optical path deflecting device according to claim 1, since the support member is directly fixed to the outer surface of the coil, the support member can be brought close to the center of the optical element. Can be small.

According to the invention of claim 3, a movable part having at least an optical element and a coil, a plurality of support members that rotatably support the movable part, a base that fixes a part of the support member, and An optical path deflecting device having a magnetic circuit fixed to a base;
The coil is disposed so as to surround the outer periphery of the optical element, a bifurcated portion is formed on at least a part of the support member, and the movable portion is supported so that the coil is sandwiched by the bifurcated portion. Therefore, the rotation axis of the movable part and the center of the force generated in the coil can be easily matched, and a good response characteristic with little resonance can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 6 show a first embodiment of the present invention, which is an example applied to an optical path deflecting device used in an optical pickup device of an information recording / reproducing apparatus using a magneto-optical disk as a recording medium. Show. FIG. 1 is a perspective view showing an arrangement relationship of optical elements of an optical pickup device. A part of the light emitted from the laser diode 1 which is a light source is reflected by the surface of the beam splitter 2 located in the emission direction, and is incident on the collimating lens 3 located in the reflection direction to be collimated. The transmitted light is reflected by the mirror (optical element) 4 positioned in the light traveling direction, and further reflected by the mirror 5 positioned in the reflection direction and enters the objective lens 6 positioned in the reflection direction. The light condensed by the objective lens 6 forms a light spot on the recording surface 8 of the magneto-optical disk 7.

  The reflected light reflected by the recording surface 8 of the magneto-optical disk 7 enters the objective lens 6, passes through the mirror 5, the mirror 4, and the collimator lens 3 and reaches the beam splitter 2 positioned in the light transmission direction. The light transmitted through the beam splitter 2 is incident on the photodetector 9. An information reproduction signal, focusing error signal, and tracking error signal can be obtained from the output of the photodetector 9. The mirror 4 is a constituent member of a galvano mirror 15 (optical path deflecting device) that can be driven by a driving mechanism (not shown), and coordinates of XYZ are set as shown. In other words, the XY plane is taken on the reflection surface 4a of the mirror 4, and the direction perpendicular to the XY plane is Z. The origin is the position of the optical axis of the light incident on the mirror 4, and the galvanometer mirror 15 rotates around an axis parallel to the X axis. The mirror 4 is a flat plate mirror made of glass, and the reflection surface 4a is coated with a reflection to increase the reflectance. Further, it is possible to configure the mirror 5 as a galvano mirror instead of the mirror 4.

  The objective lens 6 and the reflection mirror 5 are integrated and supported so as to be driven in the radial direction (arrow W direction) of the disk 7. This is a so-called separation optical system. Although not shown, the objective lens 6 is provided with a focus control mechanism that supports and drives the objective lens 7 in a direction perpendicular to the disk 7. Further, the objective lens 6 and the reflection mirror 5 are provided with an access control mechanism that integrally supports and drives them in the radial direction of the disk 7. Since various mechanisms have been proposed in the past (see, for example, Japanese Patent Laid-Open No. 7-153085), description thereof is omitted.

  FIG. 2 is a perspective view showing details of the galvanometer mirror 15, and FIG. 3 is an exploded perspective view of the constituent members of the galvanometer mirror 15 excluding the magnet. The holder 11 is formed of non-conductive plastic such as LCP, PPS, PEI, or PC, and has a substantially square frame shape. The mirror 4 supported by the holder 11 is bonded and fixed to the upper surface 11a of the holder 11 with reference to the four surfaces on the outer periphery of the mirror. A coil 10 wound in four corners is bonded and fixed to the rising portion 11 e of the holder 11 at a position surrounding the outer periphery of the mirror 4. Therefore, the mirror 4 and the coil 10 are not in direct contact with each other, and are positioned via the rising portion 11e of the holder 11.

  The two springs 12 (12-1, 12-2), which are support members that rotatably support the movable portion 14 having the mirror 4 and the coil 10, are formed by etching a thin plate of 0.05 mm beryllium copper. Is formed. Fixing portions 12a and 12b are formed at both ends of the spring, and the space between them is connected by a spring portion 12e. When viewed from the Y direction, the spring portion 12e is formed with a U-shaped portion 12e-1 having a substantially U-shaped central portion and parallel portions 12e-2 parallel to the X axis at both ends thereof. The width of the spring portion 12e is about 0.1 mm. Further, a hardened silicone gel is attached to the surface of the spring portion 12e to suppress vibration of the spring portion 12e.

  The spring 12 and the movable portion 14 are connected by fitting the boss 11c formed on the fixed portion 11b formed upright on both sides in the X direction of the holder 11 into the hole 12c formed in the fixed portion 12a of the spring 12. Positioning, bonding and fixing. On the other hand, the spring 12 and the base 13 to be described later are connected to a boss formed on the fixing portion 13b formed at both ends in the X direction of the base 13 in a hole 12d formed on the other fixing portion 12b of the spring 12. 13c is fitted, positioned, and bonded and fixed. The spring 12 is configured such that its thickness direction is parallel to the reflecting surface 4a of the mirror 4, and the surface of the spring 12 is parallel to the XZ plane. Further, the spring portions 12e of the two springs 12-1 and 12-2 are arranged symmetrically with respect to the YZ plane that is a plane perpendicular to the axis C that is the rotation axis.

  The base 13 is made of non-conductive plastic such as LCP, PPS, PEI, PC, etc., but the holder 11 and the base 13 are made of the same material and the same in order to make the expansion coefficient with temperature the same and prevent the spring 11 from being deformed. A material having a degree of linear expansion is desirable. An assembly hole 13d is formed at the center of the base 13, and attachment portions 13a are formed at both ends in the Y direction. A magnet 16 having a yoke 17 fixed to the back surface is fixedly bonded to the attachment portion 13a. The As shown in FIG. 2, the two magnets 16 are magnetized so that the opposite poles face each other, and both the magnets 16 are positioned so as to face the side 10 a on the Y direction side of the coil 10.

  The movable part 14 is constituted by the mirror 4, the coil 10, the holder 11, and the fixed part 12 a of the spring 12. The four portions 12e-2 parallel to the X axis of the two springs 12 are arranged on the axis C when the movable portion 14 rotates. Further, the center of gravity G of the movable portion 14 is located on the axis C as viewed from the Y direction, and the inertia main axis of the movable portion 14 is configured to coincide with the axis C. Therefore, the movable portion 14 is configured so as to achieve a static balance and a dynamic balance with respect to the axis C. Further, the centers of the two sides 10a and 10a where the force of the coil 10 is generated are on the axis C, and the center of the two sides 10a and the center of the magnet 16 coincide. That is, the center of the rotational torque generated on the two sides 10a is on the axis C, and the driving balance with respect to the axis C can be achieved.

  Here, the assembly of the spring 12 will be described with reference to FIGS. First, in order to fix the fixing portions 12a and 12b of the spring 12 to the holder 11 and the base 13, an assembly jig as shown in FIG. 5 is used. In the assembly jig, a first step portion 21b is formed on the tip surface 21a of the fixing pin 21, and a second step portion 21d is formed on the tip surface 21c of the first step portion 21b. It has been. Therefore, as shown in FIG. 4, the bottom surface of the base 13 is brought into contact with the front end surface 21 a of the fixing pin 21, the stepped portion 21 b is fitted into the hole 13 d of the base, and the base 13 is positioned with respect to the fixing pin 21. In this case, the base 13 is pressed against the fixing pin 21 by a pin (not shown).

  Next, by fixing the mirror 4 to the holder 11, the back surface of the mirror 4 is brought into contact with the second step portion 21 d of the pin 21, and the tip surface 21 c is fitted into the hole 11 d of the holder 11, thereby fixing pin The holder 11 and the mirror 4 are positioned with respect to 21. In this case, the reflection surface 4 a of the mirror 4 is pushed toward the fixed pin 21 by the pin 22. Note that the tip of the pin 22 is formed in a concave shape to prevent the tip of the pin 22 from getting in contact with the effective portion where the light beam of the reflecting surface 4a of the mirror 4 hits and becoming dirty. Thus, the relative positions of the base 13, the holder 11, and the mirror 4 are determined. In this state, the fixing portion 12a of the spring 12 is used as a fixing portion 11b (not visible in FIG. 4) of the holder 11, and the fixing portion 12b of the spring 12 is used as a fixing portion 13b (not visible in FIG. 4) of the base 13. Is fitted to the boss and fixed. Thereafter, the two terminals of the coil 10 are soldered to the two fixing portions 12a one by one, the pin 22 is removed, and the base 13 and the holder 11 are removed from the fixing pin 21, whereby the galvanometer mirror 15 is configured.

  Thus, when the movable part 14 is assembled to the base 13, since the mirror 4 is used for positioning, the accuracy of the position and inclination of the mirror 4 with respect to the base 13 is good. The reflecting surface 4a of the mirror 4 may be a surface opposite to the above-described embodiment, and the light beam may be incident on the mirror 4 through the hole 13d of the base 13. In this case, if the assembly jig of FIG. 5 is used, the accuracy of the position and inclination of the reflecting surfaces of the base 13 and the mirror 4 is further improved. Further, since the hole 13d is formed in the base 13 and the pin 21b for positioning the movable portion 14 is passed through, the space for the fixed pin 21 is small and the work for attaching the spring 12 is facilitated. Furthermore, since the base 13 and the movable part 14 are positioned by the single fixed pin 21, the positional accuracy of the base and the movable part can be easily obtained.

  Next, the operation of the galvanometer mirror 15 of the present embodiment will be described with reference to FIG. A current is supplied to the coil 10 from the drive circuit outside the galvanometer mirror 15 through the two springs 12 as support members. When an electric current is passed through the coil 10, forces opposite to each other in the Z direction are generated on the two sides 10 a of the coil 10 facing the magnet 16, and the movable portion 14 is rotated about the axis C. The axis C which is the rotation axis at that time is substantially parallel to the X axis. Thus, when the mirror 4 is rotated around the axis C parallel to the X axis by the galvanometer mirror 15, the reflected light of the mirror 4 is tilted and the light incident on the objective lens 6 is also tilted. Then, the light spot on the disk 7 moves in the radial direction (W direction) of the disk 7 with respect to the recording track formed on the recording surface 8 of the disk 7, and a tracking operation can be performed (FIG. 1).

  Further, as described above, the movable portion 14 is configured so that a static balance and a dynamic balance around the axis C can be obtained with respect to the axis C. The center of the two sides 10a where the force of the coil 10 is generated is on the axis C. That is, the center of the rotational torque generated on the two sides 10a is on the axis C, and the drive balance is achieved with respect to the axis C.

  As described above, the first embodiment has the following effects. Since the fixed portion of the spring 12 that is the support member to the movable portion 14 is arranged on the outer surface side of the coil 10, the center of rotation C of the support member and the center of the force generated in the coil 10 can be easily matched. Good response characteristics with little resonance can be obtained. Therefore, when the movable part 14 is rotated, it is possible to prevent the rotation axis from being shifted from the axis C or to be inclined, and good driving characteristics can be obtained. Furthermore, vibration modes other than the vibration mode in which the movable portion 14 rotates about the axis C, such as a vibration mode in which the movable portion 14 moves in the Z direction, are less likely to occur.

  Further, since the mirror 4 and the coil 10 are not in direct contact with each other, and a part of the holder 11 is positioned between them, the heat generated when the holder 11 becomes a heat insulating material and an electric current is passed through the coil 10 is applied to the mirror 4. It becomes difficult to be transmitted. Therefore, it is possible to prevent the mirror 4 from being deformed by the heat of the coil 10 and increasing the aberration of the light spot of the objective lens 6. Further, since the coil 10 is disposed so as to surround the mirror 4, the coil 10 reinforces the mirror 4, and the rigidity of the movable portion 14 is increased. Moreover, the external shape of the movable part 14 can be made small.

  Next, a second embodiment of the present invention will be described with reference to FIGS. This is a modification of the first embodiment, and the same functional parts are assigned the same numbers, and are the same as those of the first embodiment except for the explanation. In the present embodiment, the holder for supporting the mirror 4 is eliminated, and the coil 10 is directly bonded and fixed to the mirror 4. In this case, the distance between the side surface of the mirror 4 in the Y direction and the coil 10 is made as small as 0.1 mm, and an adhesive 8 (not shown) is filled and bonded between them. Then, the heat from the coil 10 to the mirror 4 becomes difficult to be transmitted by the adhesive therebetween. The interval between the mirror 4 and the coil 10 in the X direction is about 0.5 mm. This is because the four corners of the coil 10 are not completely bent at a right angle and R of about R0.5 is required.

  Further, as shown in FIG. 8A, the spring 12 is substantially Y-shaped, and a spring portion 12e-1 on a straight line from the fixing portion 12b to the base 13 along the axis C and a bifurcated shape extending from the spring portion 12e-1. A spring portion 12e-2 is formed, and fixing portions 12a bent in an L shape are formed at two positions at the tip of the spring portion 12e-2, and the fixing portion 12a is bonded and fixed to the side surface of the mirror 4 in the X direction. . The side of the coil 10 in the X direction is positioned in a space between the bifurcated spring portion 12e-2, and the bifurcated spring portion 12e-2 is configured to sandwich the width (Z direction) of the coil 10. .

  FIG. 8B shows a modification of the case of FIG. 8A, in which only the bifurcated spring part 12e-2 is formed without providing the linear spring part 12e-1. In this case, the spring portion 12e-1 and the spring portion 12e-2 are deformed in FIG. 8A, but only the spring portion 12e-2 is deformed in FIG. 8B. In the case of FIG. 8A as well, it is possible to increase the rigidity of the spring portion 12e-2 so that only the spring portion 12e-1 is deformed. The coil 10 may be wound directly around the mirror 4. About another structure, it is the same as that of 1st Embodiment.

  In the second embodiment, as described above, the spring portion (support member) 12 is configured so as to sandwich the coil 10, so that the coil 10 and the spring portion 12 do not interfere with each other, and the center of the coil 10 and the spring portion 12 is easy. Can match. Therefore, the rotation center axis of the spring portion 12 and the center of the force generated in the coil 10 can be easily matched, and a good response characteristic with little resonance can be obtained.

  Further, since the spring portion 12 is directly fixed to the mirror 4 so as to sandwich the coil 10, the spring portion 12 can be brought closer to the center portion of the mirror 4 and the movable portion 14, and thus the galvano mirror 15 can be made smaller. Furthermore, since the coil 10 and the spring portion 12 are directly fixed to the mirror 4 without interposing a holder, the number of parts is reduced, and the movable portion 14 can be reduced in weight and size.

  Further, since the gap between the mirror 4 and the coil 10 is about 0.1 mm and the adhesive is filled therewith, even if there is no holder, the heat conducted from the coil 10 to the mirror 4 is reduced and the thermal deformation of the mirror 4 can be reduced. . Needless to say, the heat transmitted to the mirror 4 can be reduced by increasing the distance. Other effects are the same as those in the first embodiment.

  FIG. 9 shows a third embodiment of the present invention, which is also a modification of the first embodiment. The same functional parts as those in the first embodiment are denoted by the same reference numerals and are the same as those in the first embodiment except for the explanation part. In the present embodiment, the spring portion 12 e is formed in a straight line, and the fixing portion 12 a is directly bonded and fixed to the surface of the coil 10. Further, the distance between the mirror 4 and the coil 10 in the X direction and the Y direction is about 0.1 mm, and the four corners of the mirror 4 are chamfered about C0.5 so as to contact the inside of the four corners of the coil 10. I'm not going to do that.

  In the third embodiment, since the spring portion 12 is directly fixed to the coil 10 as described above, a member such as a holder between the coil 10 and the spring portion 12 is unnecessary, and the fixing position of the spring portion 12 to the base 13 is not required. Can be brought closer to the center of the mirror. Therefore, the galvanometer mirror 15 can be reduced in size. Other effects are the same as those in the first embodiment.

  The present invention is not limited to the above embodiments, and various modifications and changes can be made. For example, in the above embodiment, a flat mirror is used as the optical element. However, the present invention may be applied to a device that rotates and tilts other optical elements such as a concave mirror, a hologram, and a prism. Further, the number of optical elements to be driven is not limited to one, and a plurality of optical elements may be used. Further, the mirror 4 and the holder 11 may be integrally formed of plastic, glass or the like. This reduces the number of parts and improves the positional accuracy during assembly. Further, the mirror 5 may be configured as a galvanometer mirror. The shape and material of the support member are not particularly limited. For example, the shape may be circular or plate-like. The material may be appropriately selected and used such as metal or resin.

It is the perspective view which showed the arrangement | positioning relationship of the optical element of an optical pick-up apparatus. It is the perspective view which showed the detail of the galvanometer mirror as 1st Embodiment of this invention. It is a disassembled perspective view of the structural member except a magnet. It is sectional drawing which shows the assembly of a spring. It is a perspective view of the jig used for the assembly of a spring. It is sectional drawing explaining the effect | action of a galvanometer mirror. It is a partial perspective view of the galvanometer mirror of 2nd Embodiment. It is a partially expanded side view and a partially expanded side view of a modification. It is a partial perspective view of the galvanometer mirror of 3rd Embodiment. It is the perspective view and side view of a prior art example.

Explanation of symbols

4 mirror 4a reflecting surface 10 coil 11 holder 11e rising part 12a fixing part 12-1, 12-2 spring 13 base 13a attaching part 13d hole 14 movable part 15 galvano mirror 16 magnet 17 yoke

Claims (3)

A movable portion having at least an optical element and a coil; a plurality of support members for rotatably supporting the movable portion; a base for fixing a part of the support member; and a magnetic circuit fixed to the base. In the optical path deflecting device,
An optical path deflecting device, wherein the coil is disposed so as to surround an outer periphery of the optical element, and a fixed portion of the support member to the movable portion is disposed on an outer surface side of the coil.   The optical path deflecting device according to claim 1, wherein the support member is directly fixed to an outer surface of the coil. A movable portion having at least an optical element and a coil; a plurality of support members for rotatably supporting the movable portion; a base for fixing a part of the support member; and a magnetic circuit fixed to the base. In the optical path deflecting device,
The coil is disposed so as to surround the outer periphery of the optical element, a bifurcated portion is formed on at least a part of the support member, and the movable portion is supported so that the coil is sandwiched by the bifurcated portion. An optical path deflecting device.

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