JP5272726B2 - Lens drive mechanism for optical pickup - Google Patents

Description

  The present invention relates to a lens driving mechanism for an optical pickup, and more particularly to a lens driving mechanism for an optical pickup provided with a driving source and a lens holding member.

  2. Description of the Related Art Conventionally, an optical pickup having a lens driving mechanism including a driving source and a lens holding member is known (see, for example, Patent Documents 1 to 4).

  In Patent Document 1, a stepping motor having a lead screw attached to a rotating shaft, an optical head in which a lead nut is integrally formed at one end, and the other end of the optical head are provided on the apparatus body. An optical information recording / reproducing apparatus having a penetrating shaft is disclosed. In the optical information recording / reproducing apparatus described in Patent Document 1, the lead nut is screwed into the lead screw, and the lead screw and the shaft are arranged substantially in parallel. It is configured to be able to reciprocate in the front-rear direction along the direction in which the shaft extends along with the reverse rotation. Thus, the optical head is configured to detect the return light of the light beam irradiated on the recording medium (optical card) while moving in a predetermined area.

  Further, in Patent Document 2, a stepping motor with a cam attached to a rotating shaft, a movable holder with an optical lens attached, and an arm having a protrusion that contacts the cam, There is disclosed a lens driving unit that includes a guide rail that sandwiches a holder from above and below and a unit base that is provided with a guide rail that extends substantially parallel to each other and a guide shaft. In the lens drive unit described in Patent Document 2, the movable holder reciprocates in the front-rear direction along the direction in which the guide rail extends by rotating the cam forward and backward with the protrusion of the movable holder in contact with the cam. It is configured to be able to move. Thereby, the position of the optical lens in the optical axis direction is adjusted.

  In Patent Document 3, a motor having a lead screw attached to a rotating shaft and a correction lens are attached to the other end of an arm portion having a rack gear formed at one end. An optical pickup device is disclosed that includes a lens guide shaft and a guide holder that is provided in the apparatus main body and holds the lens guide shaft in a direction substantially parallel to the direction in which the lead screw extends. In the optical pickup device described in Patent Document 3, since the rack gear is engaged with the lead screw, the lens guide shaft is configured to be able to reciprocate in the front-rear direction in accordance with forward and reverse rotation of the lead screw. ing. Thus, the position of the correction lens in the optical axis direction is adjusted.

  In Patent Document 4, a drive motor having a lead screw attached to a rotating shaft, a lens holder in which an engagement nut is integrally formed at one end and a spherical aberration correcting lens is attached, An optical pickup provided with a guide shaft provided in the apparatus main body and penetrating the other end of the lens holder is disclosed. In the optical pickup described in Patent Document 4, since the engaging nut is screwed into the lead screw and the lead screw and the guide shaft are arranged substantially in parallel, the lens holder rotates in the forward and reverse directions of the lead screw. Accordingly, it is configured to be able to reciprocate in the front-rear direction along the direction in which the guide shaft extends. As a result, the position of the spherical aberration correcting lens in the optical axis direction is adjusted.

JP-A-6-349080 JP 2008-181607 A JP 2004-335022 A JP 2006-147054 A

  However, in the optical information recording / reproducing apparatus described in Patent Document 1, since the lead nut is integrally formed with the optical head, when the stepping motor is driven to reciprocate the optical head, the lead screw and the lead It is considered that the screwed state with the nut directly affects the optical head. In particular, if the parallelism between the lead screw and the shaft that penetrates the other end of the optical head cannot be maintained due to assembly errors of components that occur when assembling the main body of the device, the rotation axis of the lead screw and the optical head The direction of movement becomes inconsistent, and “leading” is likely to occur, in which the thread of the lead nut rides on the thread of the lead screw. In this case, there is a problem that a further shift occurs between the moving direction of the optical head and the rotation axis of the lead screw, and the optical head cannot be moved normally.

  Further, in the lens driving unit described in Patent Document 2, since the protrusion that contacts the cam is integrally formed on the movable holder, when the stepping motor is driven to move the movable holder back and forth, the cam and the protrusion It is considered that the contact with the part directly affects the movable holder. In particular, if the parallelism between the lead screw and the shaft that penetrates the other end of the optical head cannot be maintained due to assembly errors of components that occur when assembling the lens drive unit, the lead screw rotation shaft and the optical head The movement direction of the lead nuts does not coincide with each other, and “leading” is likely to occur because the thread of the lead nut rides on the thread of the lead screw. In this case, there is a problem that a further shift occurs between the moving direction of the optical head and the rotation axis of the lead screw, and the optical head cannot be moved normally.

  Further, in the optical pickup device described in Patent Document 3, since the arm portion in which the rack gear is formed on the lens guide shaft is integrally formed, when the motor is driven to move the lens guide shaft back and forth, the lead It is considered that the screwed state between the screw and the rack gear directly affects the lens guide shaft. In particular, when the parallelism between the lead screw and the guide holder that is slidably held in the direction substantially parallel to the direction in which the lead screw extends is not maintained due to assembly errors of components that occur when assembling the device main body, It is easy for the rack gear thread to “catch” that it rides on the lead screw thread. In this case, there is a problem that a further shift occurs between the moving direction of the lens guide shaft and the rotating shaft of the lead screw, and the lens guide shaft cannot be moved normally.

  Also in the optical pickup described in Patent Document 4, since the engagement nut is integrally formed with the lens holder, when the lens holder is reciprocated by the drive motor, the screw between the lead screw and the engagement nut is used. It is considered that the combined state directly affects the lens holder. In particular, if the parallelism between the lead screw and the guide shaft that penetrates the other end of the lens holder cannot be maintained due to assembly errors of parts that occur when assembling the main body of the device, the thread of the engagement nut leads to the lead It becomes easy for “biting” to occur on the screw thread of the screw. In this case, there is a problem that a further shift occurs between the moving direction of the lens holder and the rotation axis of the lead screw, and the lens holder cannot be moved normally.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to provide a lens driving mechanism for an optical pickup capable of normally moving a movable part. is there.

Means for Solving the Problems and Effects of the Invention

A lens driving mechanism for an optical pickup according to an aspect of the present invention includes a driving source for rotating a lead screw, a nut member screwed to the lead screw, a lens, and a nut member movably engaged. A lens holding member that includes a first restricting portion that restricts the rotation of the nut member and is moved along with the movement of the nut member due to the rotation of the lead screw, and the engagement state between the nut member and the first restricting portion is released. A base including a second restricting portion to be suppressed, and the first restricting portion of the lens holding member and the second restricting portion of the base have a positional relationship facing each other across the nut member, and the rotation of the nut member When the restriction width of the second restriction portion in the direction is smaller than the restriction width that is the engagement width of the first restriction portion in the rotation direction of the nut member, the nut member and the first restriction portion are caused by the second restriction portion. The engagement state is released is configured to be suppressed in.

  In the lens drive mechanism of the optical pickup according to one aspect of the present invention, as described above, the nut member screwed with the lead screw and the nut member are movably engaged to restrict the rotation of the nut member. And a lens holding member that is moved along with the movement of the nut member by rotation of the lead screw, and the lens holding member is provided with a nut member that is movably engaged with the first restricting portion of the lens holding member. The driving force of the drive source (lead screw) is transmitted through the via. Thus, for example, even when a deviation occurs between the rotation axis of the lead screw and the moving direction of the lens holding member due to, for example, an assembly error of components that occurs when assembling the lens driving mechanism, the nut member is attached to the lens holding member. On the other hand, since it is movably engaged through the first restricting portion, the above-described deviation can be appropriately absorbed by the movable engagement between the nut member and the first restricting portion. As a result, the occurrence of “biting” between the nut member and the lead screw due to the above-described deviation is suppressed, so that the lens holding member serving as the movable portion can be moved normally.

  In addition, since the base including the second restricting portion that suppresses the release of the engagement state between the nut member and the first restricting portion is provided, unexpected vibration or impact is applied to the lens driving mechanism. However, since the engagement state between the nut member and the first restricting portion is always maintained, the lens holding member can be reliably moved.

  In the lens drive mechanism of the optical pickup according to the above aspect, the nut member preferably includes a first convex portion that protrudes from the outer surface of the nut member and is disposed on the second restricting portion, and the second restricting portion of the base The nut member is configured to restrict the rotation of the nut member within a predetermined angle range by the first convex portion of the nut member coming into contact with the second restricting portion. If comprised in this way, since rotation of a nut member can be stopped only in the area | region in which the 2nd control part of a base is formed, it originates in rotation exceeding the predetermined angle range of a nut member. The nut member can be easily prevented from coming off from the first restricting portion of the lens holding member.

  In the configuration in which the nut member includes the first convex portion, preferably, the second restricting portion is a groove portion having a concave cross section formed so that the first convex portion is fitted, and the second restricting portion is The groove is formed so as to extend along the direction in which the lens holding member moves. If comprised in this way, since the 2nd control part is formed in the state of the groove part which a 1st convex part fits in even during the movement of a lens holding member, a nut member is from the 2nd control part of a base. It is suppressed from coming off. Thereby, it is possible to easily suppress the engagement state between the nut member and the first restricting portion of the lens holding member from being released due to the rotation of the nut member.

  In the configuration in which the second restricting portion is a groove portion having a concave cross section, the nut member is preferably a second protrusion protruding from an outer surface at a position different from the position where the first protrusion of the nut member is provided. The first restricting portion of the lens holding member has a recess, and the nut member engages the nut with respect to the lens holding member by the second protrusion being movably engaged with the recess of the first restricting portion. It is comprised so that rotation of a member may be controlled. If comprised in this way, since the 2nd convex part of a nut member can be fitted and engaged with the recessed part of a 1st control part, rotation of the nut member with respect to a lens holding member can be controlled easily.

  In the configuration in which the nut member further includes a second convex portion, preferably, the direction in which the second convex portion of the nut member engages with the concave portion of the first restricting portion and the direction in which the second restricting portion of the base extends. It is almost the same. If comprised in this way, the direction which the 2nd control part (groove part) which is a movement direction of the nut member by rotation of a lead screw will extend, and the direction where the 2nd convex part of a nut member will engage with the recessed part of a lens holding member Since they substantially coincide, the lens holding member can be reliably moved through the nut member.

  In the configuration in which the nut member further includes the second convex portion, preferably, the concave portion of the first restricting portion is formed such that the opening width of the concave portion is widened from the bottom portion of the concave portion toward the second convex portion of the nut member. The lens holding member is configured such that the second convex portion of the nut member slides on the slope portion and fits into the first restricting portion. According to this configuration, even if the engagement state between the nut member and the lens holding member is about to be released due to unexpected vibration or impact applied to the lens driving mechanism, the second of the nut member Since the convex portion can slide on the slope portion formed on the first restricting portion of the lens holding member and fit into the first restricting portion (concave portion), the nut member and the lens holding member can be smoothly engaged. Can be done.

  In the configuration in which the first restricting portion has the inclined portion, preferably, the inclined portions are provided on both sides of the first restricting portion in the direction in which the second convex portion of the nut member crosses the first restricting portion, and The second restricting portion is a groove portion having a concave cross section formed so that the first convex portion is fitted, and the maximum distance from the slope portion on one side to the slope portion on the other side of the first restricting portion is It is larger than the width of the groove portion of the base. If comprised in this way, even when a nut member is rotated to the maximum angle within the predetermined angle range (range in which the 2nd control part (groove part) of a base was formed) where rotation is permitted, a nut member Since the second convex portion of the nut member can be present in the region where the slope portion of the first restricting portion is formed, the first restricting portion (concave portion) can be easily formed by sliding the slope portion of the second convex portion of the nut member. Can be fitted.

  In the lens driving mechanism of the optical pickup according to the above aspect, preferably, the nut member is moved to the optical axis using the rotation of the lead screw in a state where the rotation of the nut member is restricted by the first restricting portion and the second restricting portion. The lens holding member that holds the lens by moving in the direction is moved in the optical axis direction so that the spherical aberration when the laser light from the light source is focused on the recording layer of the disk is corrected by moving the lens. Has been. If comprised in this way, when correcting spherical aberration with a lens drive mechanism, the lens holding member movable with a lens can be moved normally, Therefore Correction of spherical aberration can be performed reliably.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view showing a schematic configuration of a disk device including an optical pickup having a lens driving mechanism according to an embodiment of the present invention. FIG. 2 is a perspective view showing the configuration of the optical pickup having the lens driving mechanism according to the embodiment shown in FIG. 3 to 10 are views showing the detailed structure of the lens driving mechanism of the optical pickup according to the embodiment shown in FIG. First, the structure of an optical pickup 90 having a lens driving mechanism 50 according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, an optical pickup 90 having a lens driving mechanism 50 according to an embodiment of the present invention is provided on two guide shafts 2 and 3 which are provided on a sheet metal chassis 1 and are arranged substantially parallel to each other. It is supported movably. The optical pickup 90 is configured to reciprocate between the guide shafts 2 and 3 in the A direction by driving the motor 5 to which the screw 4 is attached.

  When the optical pickup 90 is viewed in the B1 direction of FIG. 1, as shown in FIG. 2, the optical pickup 90 has an optical system 20 composed of a plurality of optical components incorporated in a resin base 10. Yes. The configuration of the optical system 20 will be described in detail. As shown in FIG. 3, the optical system 20 (within the one-dot chain line) includes a semiconductor laser element 21, a diffraction grating 22, a polarization beam splitter 23, and a collimating lens. 24, a quarter-wave plate 25, a mirror 26, an objective lens 27, a cylindrical lens 28, and a photodetector 29 are arranged at predetermined positions inside the base 10. The semiconductor laser element 21 and the collimating lens 24 are examples of the “light source” and “lens” of the present invention, respectively.

  The semiconductor laser element 21 has a function of irradiating the recording layer 71 of the disk 70 with laser light having a predetermined wavelength when reading information recorded on the disk 70 or writing information to the disk 70. Yes. Note that the wavelength of the laser light emitted from the semiconductor laser element 21 is appropriately selected depending on the type of disk that is read and written by the optical pickup 90. Since the disc 70 in this embodiment is intended for a large-capacity optical disc (for example, a Blu-ray Disc) in which the recording layer 71 is multilayered, the optical pickup 90 has a blue laser beam having an oscillation wavelength of about 405 nm. Is emitted from the semiconductor laser element 21.

  As shown in FIG. 3, the diffraction grating 22 has a function of diffracting laser light emitted from the semiconductor laser element 21 and dividing it into a main beam and two sub beams. The polarization beam splitter 23 reflects the laser incident light from the semiconductor laser element 21 toward the collimating lens 24, while the laser beam reflected by the disk 70 and returning to the polarization beam splitter 23 is received by the photodetector 29 after reaching the disk 70. It has a function of transmitting toward. The collimator lens 24 has a function of converting the laser incident light from the polarization beam splitter 23 into parallel light.

  Here, in this embodiment, the collimating lens 24 is configured to be reciprocally movable in the optical axis direction (direction C in FIG. 3) by a lens driving mechanism 50 (details will be described later). Thus, the laser light transmitted through the collimator lens 24 is configured to be emitted as divergent light or convergent light without necessarily being composed of only parallel light.

  Here, the disc 70 targeted by the optical pickup 90 usually has a recording layer 71 for recording information having a two-layer structure (L0 layer 72 and L1 layer 73) according to the standard. In this case, since the L0 layer 72 and the L1 layer 73 (see FIG. 3) have different thicknesses between the protective layer 74 formed of a transparent resin and the protective layer 75 (cover layer), the protective layer 74 (75) Spherical aberration occurs in the transmitted laser light. Therefore, in the optical pickup 90, the convergent divergence state of the laser light incident on the objective lens 27 is changed by moving the collimating lens 24 by a predetermined amount in the optical axis direction (C direction) using the lens driving mechanism 50. It is configured to be able to correct spherical aberration.

  As shown in FIG. 3, the quarter wavelength plate 25 has a function of converting the laser light emitted from the collimating lens 24 into circularly polarized light. The laser light that is reflected by the disk 70 and then re-enters the quarter-wave plate 25 is converted into linearly polarized light and emitted. In this case, the polarization direction of the emitted linearly polarized light has a polarization direction rotated by 90 degrees with respect to the polarization direction of the linearly polarized light emitted from the semiconductor laser element 21. Further, the mirror 26 is provided to allow the laser light from the quarter wavelength plate 25 to enter perpendicularly to the disk surface of the disk 70.

  The objective lens 27 has a function of condensing incident laser light on the L0 layer 72 or the L1 layer 73 of the disk 70. The objective lens 27 is mounted on an actuator 30 (lens driving mechanism of the objective lens 27), and the objective lens 27 is moved by the actuator 30 in a focus direction (optical axis direction) and a track direction (radial direction of the disk 70). It is configured to be possible. Thus, the focusing control and tracking control in the optical pickup 90 can be performed.

  The light reflected by the disk surface of the disk 70 is transmitted through the objective lens 27, is reflected again by the mirror 26, and passes through the quarter wavelength plate 25, the collimator lens 24, and the polarization beam splitter 23 in this order. Then, astigmatism is given by the cylindrical lens 28, and the light is condensed on the light receiving surface 29 a of the photodetector 29. The photodetector 29 has a function of converting incident optical information into an electrical signal and outputting it to an RF amplifier (not shown). The electrical signal output from the photodetector 29 is processed and converted into a reproduction signal, a focus error signal, a tracking error signal, and the like. The optical pickup 90 is configured to read information recorded on the disk 70 using the optical system 20 including the plurality of optical components described above.

  Next, the detailed structure of the lens driving mechanism 50 will be described with reference to FIGS.

  As shown in FIG. 4, the lens driving mechanism 50 includes a stepping motor 52 having a lead screw 51 attached to the rotating shaft and fixed to the base 10, a resin lead nut 53 screwed into the lead screw 51, A resin lens holder 54 to which the collimating lens 24 is attached, a guide shaft 55 that is fixed to the base 10 and guides the movement of the lens holder 54, and biases the lens holder 54 in one direction (C2 direction). A coil spring 56 is provided. The stepping motor 52, the lead nut 53, and the lens holder 54 are examples of the “drive source”, “nut member”, and “lens holding member” of the present invention, respectively.

  As shown in FIGS. 4 and 5, the lens holder 54 is provided with a through hole 54b into which the guide shaft 55 is inserted in a substantially central portion 54a of the main body. A lens holding portion 54c that holds the collimating lens 24 is integrally formed on the A1 side as viewed from the through hole 54b, and a lead nut 53 is fitted on the A2 side as viewed from the through hole 54b. A rotation restricting portion 54d having a recess 54e is integrally formed. The recess 54e has a width of about 1.8 mm in the A direction and is formed to be recessed in the C1 direction. The rotation restricting portion 54d is an example of the “first restricting portion” in the present invention.

  Here, in this embodiment, as shown in FIG. 4, the stepping motor 52 is in a state where the lead screw 51 of the stepping motor 52 and the lead nut 53 are screwed together, and the end portion on the C1 side of the lead screw 51 is a lens. The holder 54 is fixed to the base 10 by being inserted into a through hole 54 f provided in the rotation restricting portion 54 d of the holder 54. Further, the lead nut 53 screwed into the lead screw 51 is configured to be engaged with the rotation restricting portion 54d of the lens holder 54 while moving in the C1 direction so that the rotation of the lead nut 53 is restricted. Yes. Thereby, the lens holder 54 is configured to be able to slide in the C1 direction by transmitting the driving force of the stepping motor 52 via the lead nut 53 engaged with the rotation restricting portion 54d.

  In the present embodiment, as shown in FIGS. 5 and 6, the lead nut 53 includes a main body 53a formed in a substantially square shape when viewed from the front, and a B2 side outer surface on the B2 side of the main body 53a. And a convex portion 53d protruding in the B1 direction from the outer surface on the opposite side (B1 side) to the side where the convex portion 53b is formed across the screw hole 53c. Yes. The lead nut 53 is formed so that the convex portions 53b and 53d have substantially the same shape. The convex portion 53b (53d) has a width of about 1.2 mm in the A direction. As a result, the protrusion 53b (53d) of the lead nut 53 is fitted into the recess 54e (width in the A direction: about 1.8 mm) of the rotation restricting portion 54d, whereby the rotation of the lead nut 53 is restricted. Has been. Since the convex portions 53b and 53d are formed in substantially the same shape, the rotation of the lead nut 53 can be restricted regardless of which of the convex portions 53b or 53d is fitted into the concave portion 54e of the rotation restricting portion 54d. It is configured as follows. The convex portions 53b and 53d are examples of the “second convex portion” and the “first convex portion” in the present invention.

  In the present embodiment, as shown in FIGS. 5 and 7, in the recess 54 e of the lens holder 54, the opening width (width in the A direction) of the recess 54 e increases from the bottom 54 g of the recess 54 e toward the opening 54 h. It has the slope part 54i which consists of a flat surface formed in this way. Further, the slope portions 54i are formed on both sides of the recess 54e in the A direction, and are inclined with respect to the rotation axis of the lead screw 51 at an angle of about 60 degrees. Thereby, when the convex part 53b (53d) of the lead nut 53 rotates and engages with the concave part 54e of the rotation restricting part 54d, the edge 53e of the convex part 53b (53d) contacts the slope part 54i and the slope part 54i. It is configured to be fitted into the recess 54e while sliding upward in the direction of arrow P (see FIG. 7). Here, as shown in FIG. 7, the edge 53e of the convex portion 53b (53d) is chamfered so as to have a curved surface. Therefore, when the convex portion 53b (53d) contacts the slope portion 54i, the curved portion (edge 53e) of the convex portion 53b (53d) that is chamfered slides on the slope portion 54i in the direction of the arrow P while the concave portion 54e. It is comprised so that it may fit in smoothly.

  In the present embodiment, as shown in FIG. 8, the base 10 is a region where the convex portion 53d (the convex portion 53b) of the lead nut 53 that moves by engaging with the lens holder 54 in the bottom surface 10a is opposed. The regulation groove portion 11 is integrally provided. FIG. 8 shows the structure of the base 10 as viewed from the B2 side with some components of the lens driving mechanism 50 (see FIG. 4) removed. The restriction groove 11 is formed to extend along the C direction in which the lead nut 53 moves. Further, when the restriction groove portion 11 is viewed from the cross section of the base 10, as shown in FIG. 6, it has a concave cross section so as to surround the periphery of the convex portion 53 d (53 b) of the lead nut 53. The restriction groove portion 11 is an example of the “second restriction portion” and the “groove portion” in the present invention.

  Further, as shown in FIG. 6, the maximum distance L1 (about 3.2 mm) from the slope portion 54i on the A1 side to the slope portion 54i on the A2 side of the rotation restricting portion 54d is the concave shape of the restriction groove portion 11 of the base 10. It is comprised so that it may become larger than the width | variety D1 (about 2.6 mm) of the cross-sectional direction (A direction). Thus, for example, as shown in FIG. 9, when the lens holder 54 is driven by the stepping motor 52 and moves in the C direction, or when the lens holder 54 is stationary at the same position, the lens driving mechanism 50 is driven. Even when unexpected external vibration or impact is applied to the lens holder 54 and the lens holder 54 is displaced in the C1 direction, as shown in FIG. 10, the rotational displacement of the lead nut 53 (the convex portion 53d) causes the width D1 of the restricting groove portion 11. Is kept within the range. In this case, as shown in FIG. 7 and FIG. 10, the convex portion 53b on the B2 side of the lead nut 53 is within the range where the slope portion 54i is formed (maximum distance L1 (about 3.2 mm)) and the slope portion 54i. It is kept in contact. Therefore, the convex portion 53b of the lead nut 53 slides in the P direction (see FIG. 7) on the inclined surface portion 54i of the lens holder 54 that is always urged in the C2 direction by the coil spring 56, and is in the original engaged state. (See FIGS. 4 and 6). In addition, the direction (A direction) of the maximum distance L1 in FIG. 6 is an example of the “direction in which the second convex portion of the nut member crosses the first restricting portion” in the present invention.

  As shown in FIG. 2, the optical pickup 90 has an optical system 80 including a plurality of optical components incorporated in the base 10. In the optical system 80, a semiconductor laser element 81, a polarization beam splitter 83, a collimating lens 84, a mirror 86, an objective lens 87, a cylindrical lens 88, and a photodetector 89 are arranged at predetermined positions inside the base 10. Has been configured. The optical pickup 90 in the present embodiment is configured to be able to read information recorded on a disc (CD, DVD, etc.) other than an optical disc having a multilayered recording layer. Therefore, the semiconductor laser element 81 used in the optical system 80 is a two-wavelength laser element capable of emitting red laser light having an oscillation wavelength of about 650 nm and infrared laser light having an oscillation wavelength of about 780 nm. It is configured as. Since the optical system 80 targets CDs and DVDs, the spherical aberration as much as that of the disk 70 does not occur. Therefore, the optical system 80 is not provided with a lens driving mechanism that moves the collimating lens 84 for the purpose of correcting spherical aberration. The structure of the optical system 80 other than the lens driving mechanism is substantially the same as the configuration of the optical system 20 described above.

  In this embodiment, as described above, the lead nut 53 that is screwed with the lead screw 51 and the rotation restricting portion 54d that engages the lead nut 53 so as to be movable and restricts the rotation of the lead nut 53 are included. And a lens holder 54 that is moved in the C direction along with the movement of the lead nut 53 in the C direction by the rotation of 51, so that the lens holder 54 is movably engaged with the rotation restricting portion 54 d of the lens holder 54. The driving force of the stepping motor 52 (lead screw 51) is transmitted through 53. Thereby, for example, even when a deviation occurs between the rotation axis of the lead screw 51 and the moving direction of the lens holder 54 due to an assembly error of components generated when the lens driving mechanism 50 is assembled, the lead nut 53 is not attached to the lens. Since the holder 54 is movably engaged via the rotation restricting portion 54d, the above-described deviation can be appropriately absorbed by the movable engagement of the lead nut 53 and the rotation restricting portion 54d. As a result, the occurrence of “biting” between the lead nut 53 and the lead screw 51 due to the above-described deviation is suppressed, and the lens holder 54 serving as the movable portion is normally slid in the C direction. Can be made.

  In the present embodiment, the optical pickup 90 (lens drive mechanism 50) is provided with the base 10 including the restriction groove portion 11 that suppresses the release of the engagement state between the lead nut 53 and the rotation restriction portion 54d. Even when unexpected vibration or impact is applied, the engagement state between the lead nut 53 and the rotation restricting portion 54d is always maintained, so that the lens holder 54 can be reliably moved in the C direction.

  Further, in the present embodiment, the restriction groove portion 11 of the base 10 is configured to restrict the rotation of the lead nut 53 within a predetermined angle range by the convex portion 53d of the lead nut 53 coming into contact with the restriction groove portion 11. As a result, the rotation of the lead nut 53 can be stopped only in the region where the restriction groove portion 11 of the base 10 is formed. Therefore, the lead nut 53 is rotated by exceeding the predetermined angular range. It is possible to easily prevent the nut 53 from coming off from the rotation restricting portion 54d of the lens holder 54.

  Further, in the present embodiment, the restriction groove portion 11 is formed so that the concave cross section extends along the direction (C direction) in which the lens holder 54 moves, so that the restriction groove portion 11 even during movement of the lens holder 54. Is formed in the state of a groove portion into which the convex portion 53d is fitted, so that the lead nut 53 is suppressed from coming off from the restriction groove portion 11 of the base 10. Thereby, it is possible to easily prevent the engagement state between the lead nut 53 and the rotation restricting portion 54d of the lens holder 54 from being released due to the rotation of the lead nut 53.

  In the present embodiment, the lead nut 53 is configured such that the rotation of the lead nut 53 relative to the lens holder 54 is regulated by engaging the convex portion 53b with the concave portion 54e of the rotation regulating portion 54d. As a result, the convex portion 53b of the lead nut 53 can be fitted and engaged with the concave portion 54e of the rotation restricting portion 54d, so that the rotation of the lead nut 53 relative to the lens holder 54 can be easily restricted.

  In the present embodiment, the direction in which the convex portion 53b of the lead nut 53 engages with the concave portion 54e of the rotation restricting portion 54d (C1 direction) and the direction in which the restricting groove portion 11 of the base 10 extends (C direction) are substantially omitted. By configuring so as to be the same, the direction in which the restriction groove portion 11 that is the moving direction of the lead nut 53 due to the rotation of the lead screw 51 extends and the convex portion 53 b of the lead nut 53 engage with the concave portion 54 e of the lens holder 54. Since the directions substantially coincide with each other, the lens holder 54 can be reliably moved through the lead nut 53.

  Further, in the present embodiment, the opening width (width in the A direction in FIG. 7) of the recess 54e is formed in the recess 54e of the rotation restricting portion 54d from the bottom 54g of the recess 54e toward the protrusion 53b (opening 54h) of the lead nut 53. And the lens holder 54 is configured such that the convex portion 53b of the lead nut 53 slides in the P direction to fit in the rotation restricting portion 54d. Even when the engagement state between the lead nut 53 and the lens holder 54 is about to be released due to unexpected vibration or impact applied to the lens driving mechanism 50, the convex portion 53b of the lead nut 53 Since the slope portion 54i formed on the rotation restricting portion 54d of the lens holder 54 can be slid and fitted into the rotation restricting portion 54d (recessed portion 54e), the lead It is possible to perform engagement of the bets 53 and the lens holder 54 smoothly.

  Further, in the present embodiment, the maximum distance L1 (about 3.2 mm) from the slope portion 54i on the A1 side to the slope portion 54i on the A2 side of the rotation restricting portion 54d is defined as a concave cross section of the restriction groove portion 11 of the base 10. By making it larger than the width D1 (about 2.6 mm) in the direction (A direction), it is within a predetermined angular range in which the rotation of the lead nut 53 is allowed (range in which the regulation groove portion 11 of the base 10 is formed). Even when the lead nut 53 is rotated to the maximum angle, the convex portion 53b of the lead nut 53 exists in the region where the slope portion 54i of the rotation restricting portion 54d is formed. It can be easily fitted into the rotation restricting portion 54d (recessed portion 54e) by sliding in the direction.

  In the present embodiment, the lens driving mechanism 50 is moved in the optical axis direction (C direction) using the rotation of the lead screw 51 in a state where the rotation of the lead nut 53 is regulated by the rotation regulating portion 54d and the regulating groove portion 11. By moving the lens holder 54 holding the collimating lens 24 in the optical axis direction, the laser light from the semiconductor laser element 21 is condensed on the recording layer 71 (L0 layer 72 and L1 layer 73) of the disk 70. The spherical aberration at the time of correction is corrected by the movement of the collimating lens 24. Thereby, when correcting the spherical aberration by the lens driving mechanism 50, the lens holder 54 that can move together with the collimating lens 24 can be moved normally, so that the spherical aberration can be corrected reliably.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above-described embodiment, an example in which the resin-made lead nut 53 is used has been described. However, the present invention is not limited thereto, and a metal nut member made of sheet metal may be used.

  In the above embodiment, the example in which the convex portion 53d and the convex portion 53b of the lead nut 53 are formed on the opposite sides with the screw hole 53c interposed therebetween is shown, but the present invention is not limited thereto, and the convex portion 53d and The protrusion 53b may be formed so as to have a positional relationship other than the opposite side across the screw hole 53c. For example, the “second convex portion” of the present invention that is the convex portion 53b is approximately the same as the “first convex portion” of the present invention that is the convex portion 53d in the rotational direction of the lead nut 53 around the screw hole 53c. You may form in the position which changed direction only 90 degree | times.

  In the above embodiment, the lead nut 53 is provided with the convex portion 53b (53d) and the base 10 and the lens holder 54 are provided with the concave portions (the restriction groove portion 11 and the concave portion 54e). However, the present invention is not limited thereto, and a concave portion may be provided on the lead nut side, and a convex portion may be provided on the base and the lens holder side so that the lead nut and the lens holder are engaged. Even with this configuration, the lens holder can be indirectly moved using the rotation of the lead screw 51 in a state where the engagement state of the lead nut with respect to the lens holder is appropriately maintained. Similar effects can be obtained.

  In the above-described embodiment, the example in which the inclined surface portion 54i of the concave portion 54e of the lens holder 54 is formed to have a flat surface is shown, but the present invention is not limited to this, and the inclined surface portion 54i is formed to have a curved surface. May be.

  In the above-described embodiment, the example in which the lead screw 51 screwed with the lead nut 53 is directly attached to the rotating shaft of the stepping motor 52 has been described. However, the present invention is not limited thereto, and the stepping motor 52 includes a plurality of gears. You may comprise so that a lead screw may be rotationally driven indirectly through a member.

  Moreover, in the said embodiment, although the example which formed the control groove part 11 so that it had a concave-shaped (U-shaped) cross section was shown, this invention is not limited to this, The control groove part 11 is substantially V-shaped. You may form so that it may have a cross section.

1 is a perspective view showing a schematic configuration of a disk device including an optical pickup having a lens driving mechanism according to an embodiment of the present invention. It is the perspective view which showed the structure of the optical pick-up which has the lens drive mechanism by one Embodiment shown in FIG. It is the schematic shown about the optical system of the optical pick-up by one Embodiment shown in FIG. It is the top view which showed the detailed structure of the lens drive mechanism of the optical pick-up by one Embodiment shown in FIG. FIG. 2 is an exploded perspective view showing a detailed structure of a lens driving mechanism of the optical pickup according to the embodiment shown in FIG. 1. It is sectional drawing which showed the detailed structure of the lens drive mechanism of the optical pick-up by one Embodiment shown in FIG. FIG. 2 is an enlarged plan view showing a detailed structure of a lens driving mechanism of the optical pickup according to the embodiment shown in FIG. 1. It is the top view which showed the detailed structure of the lens drive mechanism of the optical pick-up by one Embodiment shown in FIG. It is the top view which showed the detailed structure of the lens drive mechanism of the optical pick-up by one Embodiment shown in FIG. It is sectional drawing which showed the detailed structure of the lens drive mechanism of the optical pick-up by one Embodiment shown in FIG.

Explanation of symbols

10 base 11 regulation groove (second regulation part, groove)
21 Semiconductor laser element (light source)
24 Collimating lens (lens)
51 Lead screw 52 Stepping motor (drive source)
53 Lead nut (nut member)
53b Convex part (second convex part)
53d Convex part (first convex part)
54 Lens holder (lens holding member)
54d Rotation restriction part (first restriction part)
54e Concave portion 54i Slope portion 70 Disc 71 Recording layer

Claims (8)

A drive source for rotating the lead screw;
A nut member screwed into the lead screw;
A lens holding member that holds the lens and includes a first restricting portion that movably engages the nut member and restricts the rotation of the nut member, and is moved along with the movement of the nut member by the rotation of the lead screw. When,
A base including a second restricting portion that suppresses release of the engagement state between the nut member and the first restricting portion ;
The first restricting portion of the lens holding member and the second restricting portion of the base have a positional relationship facing each other with the nut member interposed therebetween,
When the restriction width of the second restriction portion in the rotation direction of the nut member is smaller than the restriction width that is the engagement width of the first restriction portion in the rotation direction of the nut member, the second restriction portion causes the A lens driving mechanism of an optical pickup configured to suppress release of an engagement state between a nut member and the first restriction portion . The nut member includes a first protrusion that protrudes from an outer surface of the nut member and is disposed on the second restricting portion.
The second restricting portion of the base is configured to restrict the rotation of the nut member within a predetermined angle range when the first convex portion of the nut member abuts on the second restricting portion. The lens driving mechanism of the optical pickup according to claim 1. The second restricting portion is a groove portion having a concave cross section formed so that the first convex portion is fitted therein.
The lens driving mechanism of the optical pickup according to claim 2, wherein the second restricting portion is formed such that the groove portion extends along a moving direction of the lens holding member. The nut member further includes a second convex portion protruding from the outer surface at a position different from a position where the first convex portion of the nut member is provided,
The first restricting portion of the lens holding member has a recess,
The nut member is configured such that rotation of the nut member with respect to the lens holding member is restricted when the second convex part is movably engaged with the concave part of the first restricting part. The lens drive mechanism of the optical pickup according to claim 3.   The direction in which the second convex portion of the nut member engages with the concave portion of the first restricting portion is substantially the same as the direction in which the second restricting portion of the base extends. Lens drive mechanism for optical pickup. The concave portion of the first restricting portion has a slope portion formed so that an opening width of the concave portion is widened from a bottom portion of the concave portion toward the second convex portion of the nut member,
6. The optical pickup according to claim 4, wherein the lens holding member is configured such that the second convex portion of the nut member slides on the slope portion and fits into the first restricting portion. Lens drive mechanism. A pair of the slope portions are provided on both sides of the first restricting portion in a direction in which the second projecting portion of the nut member crosses the first restricting portion, and the second restricting portion is provided with the first projecting portion. It is a groove having a concave cross section formed so that the part fits in,
The lens driving mechanism for an optical pickup according to claim 6, wherein a maximum distance from the slope portion on one side of the first restricting portion to the slope portion on the other side is greater than a width of the groove portion of the base.   The nut member is moved in the optical axis direction using the rotation of the lead screw in a state where the rotation of the nut member is restricted by the first restricting portion and the second restricting portion, and the lens is held. The spherical aberration at the time of condensing the laser beam from the light source on the recording layer of the disk is corrected by moving the lens by moving the lens holding member in the optical axis direction. The lens drive mechanism of the optical pickup according to any one of?

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