JP2008065958A - Lens driving mechanism and optical pickup equipped with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens driving mechanism capable of securing a sufficient scrolling width of a lens holding part while thinning an optical pickup. <P>SOLUTION: The lens driving mechanism 50 is provided with an objective lens 2 for condensing optical beams on an optical disk, and a lens holder 10 for holding the objective lens 2 to move with respect to the optical disk. Light reflected by a rising mirror 102 having a slope where a reflection surface 102a is directed to the lens holder 10 is made incident as an optical beam on the objective lens 2. The lens holder 10 is disposed so that its end faces the rising mirror 102. The end of the lens holder 10 has a notch on the rising mirror 102 side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lens drive mechanism for an optical pickup that records and reproduces information by irradiating an optical recording medium with a light beam, and an optical pickup including the same.

  An optical pickup that records and / or reproduces information by irradiating an optical recording medium with a light beam (hereinafter, “recording and / or reproduction” is simply referred to as “recording / reproduction”) is widely known. In general, an optical pickup includes an optical body portion provided with an optical system such as a light source, a beam splitter, and a photodetector, and a lens driving device portion having a driving means for driving the objective lens and the objective lens. It is configured.

  An optical pickup collects a light beam from a light source on a predetermined surface of an optical recording medium by an objective lens, and causes a photodetector to receive reflected light reflected by the optical recording medium. Recording / reproducing information.

  Currently, a plurality of types of optical recording media such as CD (Compact Disc), DVD (Digital Versatile Disc), and BD (Blu-ray Disc) are used for recording and reproducing information. These optical recording media have different recording / reproducing surface positions for recording / reproducing information depending on the type. Therefore, an optical pickup capable of recording / reproducing a plurality of types (at least two types) of optical recording media adjusts the position of the objective lens by driving the lens driving unit and focuses the light beam. Has changed. As a result, a plurality of types of optical recording media can be recorded / reproduced with one optical pickup.

  The configuration of the conventional lens driving unit will be described below with reference to FIGS. 14 (a) and 14 (b) and FIGS. 15 (a) to 15 (e).

  Here, a case where an optical disk is used as an optical recording medium will be described as an example.

  FIGS. 14A and 14B are diagrams showing an optical pickup 600 that performs recording / reproduction of a plurality of types of optical recording media, FIG. 14A is a schematic plan view, and FIG. It is a schematic side view.

  The optical pickup 600 includes a lens driving device 200 and an optical system 300, and the lens driving device 200 and the optical system 300 are attached and fixed to a pickup base 400. The optical system 300 includes a rising mirror 302, a collimator lens 303, a beam splitter 304, a sensor lens 305, a light receiving element 306, a diffraction grating 307, and a semiconductor laser 308.

  As shown in FIG. 14A, the light beam 350 emitted from the semiconductor laser 308 is split into a main beam used for recording / reproduction and a sub beam used for tracking control by passing through the diffraction grating 307. . Since the main beam and the sub beam are guided to the optical disc through the same path, both are referred to as a light beam 350 here. The light beam 350 that has passed through the diffraction grating 307 is reflected by the beam splitter 304 and passes through the collimator lens 303 to become substantially parallel light. As shown in FIG. 14B, the light beam 350 that has become substantially parallel light is guided to the objective lens 202 of the lens driving device 200 by the rising mirror 302, and is irradiated to an optical disk (not shown) by the objective lens 202. .

  The irradiated light beam 350 is reflected by irregularities called pits on the recording / reproducing surface of the optical disk. The reflected light beam 350 travels back along the optical path when entering the objective lens 202 and reaches the beam splitter 304. The light beam 350 that has passed through the beam splitter 304 is guided to the sensor lens 305. The sensor lens 305 adds astigmatism to the light beam 350 and reflects the light beam 101 onto the light receiving element 306. The light receiving element 306 converts information recorded on the optical disc from the incident light beam 350 into an electric signal, and generates a servo signal used for controlling the objective lens 202 such as autofocus and track following. The lens holder 210 holds the relative position between the optical disk and the objective lens 202 so as to be an optimum position for recording and reproducing information according to the generated servo signal. As a result, good recording / reproduction characteristics can be maintained.

  15A to 15E are diagrams showing the configuration of the lens driving device 200, FIG. 15A is a schematic plan view of the lens driving device 200, and FIG. FIG. 15C is a schematic rear view, FIG. 15D is a schematic side view, and FIG. 15E is a schematic front view. is there.

  The lens driving device 200 includes a lens holder 210, a base 215, a substrate 216, and a wire holder 217. An objective lens 202 is attached to the lens holder 210.

  In the configuration of the optical pickup 600, the light beam 350 is reflected by the rising mirror 302 and guided to the objective lens 202 before reaching the base 215, the substrate 216, and the wire holder 217. That is, the reflecting surface 302a of the rising mirror 302 is provided so as to face the direction opposite to the position where the base 215, the substrate 216, and the wire holder 217 are provided.

  Patent Documents 1 and 2 disclose optical pickups that perform recording / reproduction of a plurality of types of optical recording media having the above-described optical pickup configuration.

  On the other hand, Patent Document 3 discloses an optical pickup having a configuration in which a reflecting surface of a rising mirror is provided in a direction in which a base, a substrate, and a wire holder are provided.

  The configuration described in Patent Document 3 is shown in FIG. 16 and will be described below.

  Here, a case where an optical disk is used as an optical recording medium will be described as an example.

The optical pickup 500 mainly includes a lens holder 510, an actuator base 515, and a rising mirror 522. An objective lens 502 is attached to the lens holder 510. An optical laser 523 emitted from a light source (not shown) is reflected by the rising mirror 522, passes through the lens holder 510, and is guided to the objective lens 502. The optical laser 523 incident on the objective lens 502 is condensed by the objective lens 502 and is incident on an optical disk (not shown). Further, since the lens holder 510 can move in the vertical direction in the figure in accordance with a signal given from the outside of the lens holder 510, the position at which the optical laser 523 is condensed by the objective lens 502 is set on the optical recording medium. Can be adjusted according to the type.
JP 2002-269804 A (published on September 20, 2002) JP 2003-338062 A (published on November 28, 2003) Japanese Patent Laying-Open No. 2006-48896 (published February 16, 2006)

  In the lens driving device described in Patent Document 3, since the rising mirror 522 is not provided on the actuator base 515, the thickness of the optical pickup is increased, and it is difficult to reduce the thickness of the optical pickup. there were.

  In the lens driving device described in Patent Document 3, since the rising mirror 522 is provided below the actuator base 515, there is a problem that the optical pickup becomes thick as shown in FIG.

  In order to solve this problem, even in the optical pickups described in Patent Documents 1 and 2, a rising mirror is provided on the pickup base 400 corresponding to the actuator base 515. However, even in the optical pickups described in Patent Documents 1 and 2, it is not possible to sufficiently reduce the thickness of the optical pickup.

  The reason for this will be described. As described above, optical recording media have different recording / reproducing surfaces depending on the type. Since the recording / reproducing surfaces are different, the optical pickup needs to change the light beam condensing position on the optical recording medium in accordance with this. In order to change the light beam condensing position in the optical recording medium, it is necessary to change the positional relationship between the objective lens and the optical recording medium. That is, it is necessary to bring the objective lens closer to or away from the optical recording medium. Therefore, in order to prevent the objective lens from colliding with the rising mirror disposed on the side opposite to the optical recording medium, it is necessary to increase the distance between the objective lens and the rising mirror to some extent. Accordingly, even in the optical pickups described in Patent Documents 1 and 2, it has not been possible to sufficiently reduce the thickness of the optical pickup.

  A specific example of the problem of the lens driving device described in Patent Documents 1 and 2 will be specifically described with reference to FIGS.

  Here, a case where an optical disk is used as an optical recording medium will be described as an example.

In FIGS. 15A to 15E, for example, the optical laser 350 is optimal for the optical disc 1 in which the total thickness of the substrate is 1.2 mm and the recording surface is approximately ½ (0.6 mm) of the total thickness. Is shown in a state in focus. In this state, as shown in FIG. 15 (e), the lens holder 210 and the rising mirror 302, a distant state distance _{X 1.}

The optical disc 1 normally has a label surface on which content is written on the opposite side of the recording / reproducing surface. There is a special type of optical disk 1 that can write a figure or the like on the label surface using the laser output of the optical pickup. To write for such optical disc 1, since the focus it the light beam 350 with respect to the label surface, the distance X _1, when allowed to focus almost half of the position of the substrate total thickness Is about 0.6 mm smaller. That is, the distance between the lens holder 210 and the rising mirror 302 is shortened by about 0.6 mm.

  To prevent the tip 302b of the rising mirror 302 and the bottom surface of the lens holder 210 from interfering with each other when the distance between the lens holder 210 and the rising mirror 302 is shortened, the mirror of the lens holder 210 is used. A space for moving to the 302 side must be secured in advance. That is, a sufficient distance between the lens holder 210 and the rising mirror 302 must be secured.

  For example, when a high-density information recording / reproducing medium such as BD is used as the optical disc 1, the distance (working distance) between the optical disc 1 and the objective lens 202 is about 0.3 mm or less. Therefore, a DC voltage is applied to the lens driving mechanism in order to avoid collision between the optical disk 1 and the objective lens 202 until the optical disk 1 is set at a predetermined position after the optical disk 1 is loaded into a drive including an optical pickup. Thus, the lens holder 210 must be moved to the mirror 302 side, and the distance between the optical disk 1 and the objective lens 202 must be increased.

  For this reason, a sufficient space for moving the lens holder 210 to a position where the objective lens 202 and the optical disk 1 do not contact each other must be secured in advance.

Incidentally, for example, substrate total thickness 1.2mm, the recording surface is a light beam 351 to the optical disc 1 in a position of 1.2mm when viewed from the objective lens 202 side optimally focused, the distance _{X 1} is the substrate total It is about 0.6 mm larger than when focused at a position approximately half the thickness. That is, the distance between the lens holder 210 and the rising mirror 302 is increased by about 0.6 mm.

  In order to solve the above-described problems, an object of the present invention is to provide an optical pickup that is thinned by including a lens driving mechanism that ensures a sufficient stroke of a lens holding portion with respect to a mirror.

  In order to solve the above problems, a lens driving mechanism according to the present invention includes an objective lens that focuses a light beam on an optical recording medium, and a lens holder that holds the objective lens movably with respect to the optical recording medium. A light-reflecting light reflected by a mirror having an inclined surface whose reflecting surface faces the lens holding portion, and is incident on the objective lens as the light beam. The lens holding portion is provided so that the end faces the lens, and the end of the lens holding portion has a notch on the mirror side.

  Since the position of the recording / reproducing surface differs depending on the type of optical recording medium, it is necessary to scroll the objective lens away from or closer to the mirror depending on the type of optical recording medium.

  According to the above configuration, the mirror is provided at the end portion facing the lens holding portion with the inclined reflecting surface facing the inside of the lens holding portion. Further, since the notch is provided at the end of the lens holding part, the tip of the mirror can enter the notch. For this reason, the scroll amount of the lens holding portion is increased by the amount of the notch portion compared to the case where the notch portion is not provided. Thus, by providing a notch at the end of the lens holding portion, it is possible to secure a sufficient space for the lens holding portion to scroll while reducing the thickness of the optical pickup provided with the lens driving mechanism.

  Accordingly, since it is not necessary to secure a space for the lens holding portion to scroll by ensuring a large distance between the lens holding portion and the mirror in advance, the optical pickup provided with the lens driving mechanism can be thinned. be able to.

  In the lens driving mechanism according to the present invention, it is further preferable that the notch is formed to be inclined.

  The reflecting surface of the mirror has an inclination, and the notch portion of the lens holding portion is also inclined, so that the scroll amount is increased without contacting the lens holding portion and the mirror. be able to. Therefore, the stroke amount of the lens holding portion can be increased.

  Therefore, since the stroke amount of the lens holder can be secured larger, the optical pickup equipped with the lens driving mechanism can be made thinner.

  In the lens driving mechanism according to the present invention, it is further preferable that the inclined surface provided on the mirror side at the end of the lens holding portion is parallel to the reflecting surface of the mirror.

  Since the slope of the reflecting surface of the mirror and the slope of the notch formed at the end of the lens holding part are parallel, the distance from the reflecting surface of the mirror to the notch of the lens holding part is It becomes the same in. Thereby, a lens holding part and a mirror can be scrolled to the maximum, without contacting during a scroll. As a result, it is possible to secure the maximum range in which the lens holding portion can make a stroke.

  Therefore, since the stroke amount of the lens holder can be further ensured, the optical pickup provided with the lens driving mechanism can be further reduced in thickness.

  In the lens driving mechanism according to the present invention, it is preferable that the objective lens is located at an end of the lens driving mechanism.

  According to the above configuration, the objective lens is provided at the end of the lens holding portion. As a result, the mirror for guiding the light beam to the objective lens is also provided at the end facing the lens holding portion. Since the reflecting surface of the mirror has an inclination and the lens holding part is provided with a notch, it is possible to hold the lens further by providing the mirror at a position facing the end of the lens holding part. The scroll amount of the part can be ensured.

  Further, in the lens driving mechanism according to the present invention, further, a projecting portion for holding the lens holding portion on the outer periphery of the objective lens is a direction orthogonal to the incident direction of the light beam to the objective lens. The protrusion protruding from the lens holding part is preferably cut along the periphery of the lens holding part protruding from the lens holding part.

  According to the above configuration, the protruding portion provided on the objective lens does not protrude from the lens holding portion, and the end on the side where the protruding portion of the objective lens is cut is substantially flush with the periphery of the lens holding portion. Forming. When the lens holding portion scrolls, the lens holding portion can be scrolled to the maximum without causing the protruding projection and the mirror to contact each other.

  Moreover, in the lens driving mechanism according to the present invention, it is preferable that the end of the lens holding portion is positioned closer to the incident side of the light beam than the end of the inclined surface of the mirror on the lens holding portion side. .

  The scroll amount of the lens holding unit is determined by the distance of the narrowest interval between the lens holding unit and the mirror. Therefore, the distance between the mirror and the lens holding part can be widened by providing the tip of the mirror closest to the lens holding part so as to be positioned outside the lens holding part. That is, since the scroll amount of the lens holding part can be ensured to be larger, the optical pickup provided with the lens driving mechanism can be further reduced in thickness.

  In the lens driving mechanism according to the present invention, it is preferable that an optical path for guiding the light beam to the objective lens is further provided.

  In the present invention, since the mirror is provided so as to face the inside of the lens holding part, the optical path of the light beam is provided with a substrate, a wire holder, a base, and a lens holding part. Therefore, by providing a cutout for allowing the light beam to pass through the substrate, the wire holder, the base, and the lens holding portion, the light beam is guided to the objective lens without being blocked.

  Therefore, it is not necessary to create a new optical path that makes the lens driving mechanism thicker, and the lens driving mechanism can be made thinner.

  The present invention also includes an optical pickup equipped with the lens driving mechanism of the present invention.

  As described above, the lens driving mechanism according to the present invention is provided at the end facing the lens holding portion so that the mirror faces the inside of the lens holding portion, and the end of the lens holding portion on the mirror side. Is characterized by being cut away.

  Therefore, a sufficient distance can be secured between the end of the lens holding portion and the mirror. Therefore, there is an effect that a sufficient stroke amount of the lens holding portion with respect to the mirror can be ensured while reducing the thickness of the optical pickup provided with the lens driving mechanism of the present invention.

Embodiment 1
An embodiment according to the present invention will be described with reference to the drawings. In this embodiment, the case where an optical disk is used as an optical recording medium will be described as an example. However, the present invention is not limited to this, and an optical recording medium other than an optical disk may be used.

(Configuration of optical pickup 100)
First, the configuration of the optical pickup 100 will be described below with reference to FIGS. 2 (a) and 2 (b).

  2A and 2B are diagrams showing an optical pickup 100 that performs recording / reproduction of a plurality of types of optical recording media, FIG. 2A is a schematic plan view, and FIG. It is a schematic side view.

  The optical pickup 100 includes a lens driving mechanism 50, an optical system 110, and a pickup base 150 on which these are mounted. In the drawing, the optical system 110 is indicated by a broken line, but the rising mirror 102 is described outside the broken line for convenience. Since this point relates to the feature point of the present invention, it will be described in detail later.

(Configuration of lens driving mechanism 50)
The configuration of the lens driving mechanism 50 will be described below with reference to FIGS.

  1A to 1C are diagrams illustrating the configuration of the lens drive 50 according to the present embodiment, in which FIG. 1A is a schematic plan view, FIG. 1B is a schematic side view, and FIG. Is a schematic front view.

  As shown in FIG. 1A, the lens driving mechanism 50 includes a base 15, a substrate 16, a wire holder 17, and a driving unit 20.

  The drive unit 20 includes a lens holder 10, an objective lens 2, and wires 12a and 12b. The objective lens 2 is attached to the lens holder 10. Further, the wires 12 a and 12 b penetrating the wire holder 17 are connected to the substrate 16 and support the lens holder 10 so as not to contact the rising mirror 102. The drive unit 20 will be described in detail later.

  Here, the rising mirror 102 will be described. The rising mirror 102 constitutes the optical system 110 and is a mirror for guiding the light beam to the objective lens 2 by reflecting the light beam.

  As shown in FIG. 1B, the rising mirror 102 has a reflecting surface 102a having an angle of 45 degrees with respect to the pickup base 150, and the inside of the lens holder 10, that is, the base 15, the substrate 16, and the wire holder. It is provided at the end facing the lens holder 10 so as to face the direction in which 17 or the like is provided.

As described above, since the rising mirror 102 is provided at a position away from other members constituting the optical system 110, the rising mirror 102 is described outside the broken line indicating the optical system 110 for convenience. (Fig. 2 (a), (b))
Moreover, as shown in FIG.1 (c), the board | substrate 16 is provided with the notch 16e. Although not shown here, the lens holder 10, the base 15, and the wire holder 17 are similarly provided with cutouts.

(Configuration of the drive unit 20)
The configuration of the drive unit 20 will be described below with reference to FIGS.

  3A to 3C show the configuration of the lens holder 10, FIG. 3A is a schematic plan view showing the configuration of the drive unit 20, and FIG. 3B is along the line GG ′. It is a schematic arrow sectional drawing, (c) is a schematic front view.

  As shown in FIGS. 3A and 3B, the lens holder 10 includes a focus coil 13 and a tracking coil 14.

  The focus coil 13 is for performing focus servo for maintaining the distance between the optical disk and the objective lens 2 substantially constant, and is fixed to the lens holder 10. The tracking coil 14 is for performing tracking servo so that the focus coil 13 accurately traces information on the optical disc, and a pair of tracking coils 14 is attached and fixed to the focus coil 13.

  The terminals of the focus coil 13 and the tracking coil 14 are soldered to the relay boards 11a and 11b.

  Further, as shown in FIGS. 3A and 3C, the wires 12a and 12b are soldered to the relay boards 11a and 11b through the wire holes 10c of the lens holder 10, respectively. The lens holder 10 is provided with a notch 10b.

  Here, the lens holder 10 and the objective lens 2 constituting the drive unit 20 will be described below with reference to FIGS.

  4A is a plan view showing the lens holder 10, FIG. 4B is a plan view showing the objective lens 2, and FIG. 4C is a side view showing the objective lens 2.

  As shown in FIG. 4A, the lens holder 10 includes a notch-shaped lens mounting groove 10a for mounting the relay substrates 11a and 11b to which the wires 12a and 12b are connected and the objective lens 2.

  As shown in FIGS. 4B and 4C, the objective lens 2 includes a flange portion 2a for attaching to the lens attachment groove 10a on the outer edge portion. As shown in FIG. 2B, the brim portion 2a is partially cut so that it has a D shape. A portion of the objective lens 2 obtained by cutting the collar portion 2a so as to be D-shaped is defined as a D-cut portion 2d.

  When the objective lens 2 is attached to the lens attachment groove 10a, the D-cut portion 2d is produced so as to be substantially flush with the peripheral edge of the lens holder 10.

(Configuration of base 15)
As shown in FIG. 1B, the base 15 is attached to the lower part of the lens holder 10 and the wire holder 17, and is attached to the pickup base 150 in order to hold the lens holder 10 and the wire holder 17.

  The structure of the base 15 is demonstrated below with reference to Fig.5 (a)-(c).

  5A is a schematic plan view showing the base 15, FIG. 5B is a schematic front view, and FIG. 5C is a schematic cross-sectional view taken along the line K-K ′.

  As shown in FIG. 5C, a pair of magnets 18 a and 18 b and a plate 19 are attached and fixed to the base 15. In addition, as shown in FIG. 5A, the base 15 is provided with a wire holder mounting hole 15 b for mounting the wire holder 17. Further, as shown in FIG. 5B, the base 15 is provided with a notch 15e.

  The polarities of the magnets 18a and 18b attached to the base 15 are set together with the winding direction of the wire so that the Lorentz force generated by the drive current flowing through the wire 12 is in a predetermined direction. Further, when the plate 19 is attached and fixed to the base 15, the base 15, the magnets 18 a and 18 b, and the plate 19 constitute a magnetic circuit.

(Configuration of substrate 16)
As shown in FIG. 1B, one end of the wires 12 a and 12 b is connected to the lens holder 10 and the other end is connected to the substrate 16. The substrate 16 is connected to the wire holder 17 and the lens holder 10 through wires 12a and 12b.

  The configuration of the substrate 16 will be described below with reference to FIGS.

  6A is a schematic plan view showing the substrate 16, FIG. 6B is a schematic front view, and FIG. 6C is a schematic cross-sectional view taken along the line M-M ′.

  As shown in FIG. 6B, the substrate 16 is provided with wire attachment holes 16a for connecting the wires 12a and 12b penetrating the wire holder 17. The substrate 16 is provided with a notch 16e.

  Further, a drive signal for driving the lens holder 10 in the focusing direction (perpendicular to the recording / reproducing surface of the optical disc) and / or the tracking direction (radial direction of the optical disc) is supplied to the substrate 16 from the outside of the lens driving mechanism. Reportedly. The drive signal is transmitted from the substrate 16 to the focus coil 13 and / or the tracking coil 14 via the wires 12a and 12b and the relay substrates 11a and 11b.

(Configuration of wire holder 17)
As shown in FIG. 1B, the wire holder 17 is provided on the base 15 together with the lens holder 10, and is further connected to the lens holder 10 and the substrate 16 via wires 12a and 12b. Further, the wires 12 a and 12 b connected to the lens holder 10 and the substrate 16 penetrate the wire holder 17.

  The configuration of the wire holder 17 constituting the lens driving mechanism 50 will be described below with reference to FIGS.

  FIG. 7A is a schematic plan view showing the wire holder 17, FIG. 7B is a schematic front view, and FIG. 7C is a schematic cross-sectional view taken along the line O-O ′.

  As shown in FIGS. 7A and 7B, the wire holder 17 is provided with a base attaching portion 17 b for attaching and fixing the wire holder 17 to an end portion on the side connected to the base 15. The wire holder 17 is provided with a notch 17e.

  As shown in FIG.7 (c), the groove 17a is provided in the edge part which opposes the base attachment part 17b of the wire holder 17, and the damping material 17d is filled with the groove | channel 17a.

  Thus, the lens holder 10 forms a vibration system by the wires 12a and 12b penetrating the wire holder 17 and the damping material 17d filled in the wire holder 17. The vibration system is a mechanism for absorbing vibration generated when the lens holder 10 is scrolled.

(Configuration and operation of optical system 110)
Next, the optical system 110 constituting the optical pickup 100 will be described below with reference to FIGS. 2 (a) and 2 (b).

  The optical system 110 includes a rising mirror 102, a collimator lens 103, a beam splitter 104, a sensor lens 105, a light receiving element 106, a diffraction grating 107, and a semiconductor laser (laser) 108.

  As described above, the rising mirror 102 is shown outside the broken line indicating the optical system 110 for convenience.

  As shown in FIG. 2A, the light beam 101 emitted from the semiconductor laser 108 is divided into a main beam used for recording / reproduction and a sub beam used for tracking control by passing through the diffraction grating 107. . Since the main beam and the sub beam are guided to the optical disc through the same path, both are assumed to be the light beam 101 here. The light beam 101 that has passed through the diffraction grating 107 is reflected by the beam splitter 104 and passes through the collimator lens 103 to become substantially parallel light. The light beam 101 that has become substantially parallel light is guided to the objective lens 2 of the lens driving mechanism 50 by the rising mirror 102 via the substrate 16, the wire holder 17, and the base 15 as shown in FIG. The optical disc (not shown) is irradiated by the lens 2.

  The irradiated light beam 101 is reflected by irregularities called pits on the recording / reproducing surface of the optical disc. As shown in FIG. 2A, the reflected light beam 101 travels backward along the optical path when entering the objective lens 2 and reaches the beam splitter 104. The light beam 101 that has passed through the beam splitter 104 is guided to the sensor lens 105. The sensor lens 105 adds astigmatism to the light beam 101 and reflects the light beam 101 onto the light receiving element 106. The light receiving element 106 converts information recorded on the optical disk from the incident light beam 101 into an electrical signal, and generates a servo signal used for controlling the objective lens 2 such as autofocus and track following. Since the lens holder 10 is driven based on the generated servo signal, the relative position between the optical disc and the objective lens 2 is held so as to be an optimum position for recording / reproducing information. As a result, good recording / reproduction characteristics can be maintained.

  That is, the light beam 101 is incident on the lens driving mechanism 50 from the end opposite to the end where the notch is provided, and the light beam 101 is reflected by the reflecting surface 102a of the rising mirror 012. , And led to the objective lens 2.

(Difference in the state of the lens driving mechanism 50 due to the difference in the type of optical disk)
An object of the present invention is to reduce the thickness of an optical pickup provided with the lens driving mechanism of the present invention in order to avoid collision of an objective lens with a rising mirror disposed on the side opposite to the optical disk. An object of the present invention is to provide a lens driving mechanism capable of ensuring a sufficient distance between a lens and a rising mirror.

  For this purpose, as shown in FIG. 1B, the rising mirror 102 has the reflecting surface 102a inside the lens holder 10, that is, the direction in which the base 15, the substrate 16, the wire holder 17, and the like are provided as described above. Is provided at the end of the lens holder 10 so as to face. As a result, the light beam reaches the rising mirror 102 via the base 15, the substrate 16 and the wire holder 17.

  Therefore, as shown in FIG. 1C, the substrate 16 is provided with the notches 16e described above so as not to block the optical path of the light beam reaching the rising mirror 102. Although not shown in FIG. 1C, the lens holder 10, the base 15, and the wire holder 17 also have notches 10b, 15e, and 17e so as not to block the optical path of the light beam that reaches the rising mirror 102. Is provided.

  Thereby, the light beam emitted from the semiconductor laser reaches the rising mirror 102 and is guided to the objective lens 2 even when the base 15, the substrate 16 and the wire holder 17 are provided in the optical path.

  Further, a notch (a “notch” described in claims) is provided at an end of the lens holder 10 on the side where the rising mirror 102 is provided.

  By cutting out the end of the lens holder 10, the tip of the rising mirror 102 is higher than the bottom surface of the lens holder 10 from the pickup base 150. The amount that can be stroked to the pickup base 150 side of the lens holder 10 is increased by the amount higher than the tip of the rising mirror 102 and the bottom surface of the lens holder 10.

  Therefore, it is possible to prevent physical interference between the objective lens 2 and the rising mirror 102 even if the lens holder 10 strokes toward the pickup base 150 due to the type of optical disk to be recorded / reproduced. .

  Further, the notch provided in the lens holder 10 may have any shape, but it is preferable that the notched surface is a notch, and the notched slope is the rising mirror 102. It is more preferable to cut out so that it may become parallel with the reflective surface 102a.

  The amount that the lens holder 10 can stroke toward the pickup base 150 is the same value as the distance of the portion where the distance between the rising mirror 102 and the lens holder 10 is the narrowest.

  Therefore, the stroke amount to the pickup base 150 side of the lens holder 10 can be maximized by notching a slope that is parallel to the reflecting surface 102a.

  Furthermore, the position where the rising mirror 102 is provided can be freely changed within the range in which the light beam can be guided to the objective lens 2 while maintaining the stroke amount of the lens holder 10 toward the pickup base 150. The end of the lens holder 10 is preferably provided so as to be located inside the tip of the rising mirror 102.

  Specific examples will be described with reference to FIGS. 8A and 8B to FIGS. 10A and 10B.

  8A and 8B are views showing the state of the lens driving mechanism 50 at the time of recording / reproducing of the optical disc 1, wherein FIG. 8A is a schematic sectional view, and FIG. 8B is a schematic side view. is there.

  FIGS. 9A and 9B are views showing the state of the lens driving mechanism 50 at the time of writing on the optical disc 1a capable of writing on the label surface, and FIG. 9A is a schematic sectional view. (B) is a schematic side view.

  FIGS. 10A and 10B are diagrams showing the state of the lens driving mechanism 50 when the information recording / reproducing apparatus is filled with the optical disc 1b that needs to ensure a large working distance. FIG. It is sectional drawing, (b) is a schematic side view.

  Here, the optical disc shown in FIGS. 8A and 8B to FIGS. 10A and 10B will be described.

  An optical disk 1 shown in FIGS. 8A and 8B is an optical disk having a total substrate thickness of 1.2 mm and a recording surface at a position approximately 1/2 (0.6 mm) of the total thickness, for example.

  An optical disc 1a shown in FIGS. 9A and 9B is an optical disc having a label surface on which a figure or the like can be written on the bottom surface of the optical disc 1a on the lens holder 10 side, for example. That is, the optical disk 1a is an optical disk having a total substrate thickness of 1.2 mm and a writing surface on the bottom surface on the lens holder 10 side.

  An optical disc 1b shown in FIGS. 10A and 10B is a high-density optical disc that records and reproduces information using, for example, a blue laser. Since the distance (working distance) between the objective lens 2 and the optical disk 1b is narrow during recording / reproduction, the optical disk 1b needs to prevent the optical disk 1b and the objective lens 2 from contacting each other until recording / reproduction.

  When recording / reproducing with respect to the optical disc 1, as shown in FIG. 8A, the lens holder 10 passes the notches 16e, 17e and 15e, and reflects the light beam 101 reflected by the rising mirror 102. The position of the objective lens 2 is adjusted so that the objective lens 2 is focused on the recording surface of the optical disc 1.

  At this time, as shown in FIG. 8B, the height from the pickup base 150 is higher for the objective lens 2 than for the rising mirror tip 102b. There is no contact.

  Next, when recording is performed on the optical disc 1a, as shown in FIG. 9A, the lens holder 10 has a light beam 101 incident along the same path as that shown in FIG. The position of the objective lens 2 is adjusted so as to be in focus.

  As described above, when the position of the objective lens 2 is adjusted, the height of the objective lens 2 from the pickup base 150 is approximately 0.6 mm lower than when the focus is set to a position that is ½ of the total thickness of the substrate. It has become.

  As a result, as shown in FIG. 9B, the height from the pickup base 150 of the end 2c on the pickup base 150 side of the objective lens 2 is lower than that of the rising mirror tip 102b.

  However, the lens holder 10 can be stroked to the pickup base 150 side without contact between the objective lens 2 and the rising mirror 102 due to the notch provided at the end of the lens holder 10.

  Next, when the optical disk 1b is filled in the information recording / reproducing apparatus, as shown in FIG. 10 (a), the lens holder 10 prevents the objective lens 2 and the optical disk 1b from contacting the objective lens 2 and the optical disk 1b. The position of the objective lens 2 is adjusted so as to ensure the maximum interval.

  That is, FIGS. 10A and 10B show a state in which the lens holder 10 is stroked most toward the rising mirror 102 side.

  As a result, as shown in FIG. 10B, the height from the pickup base 150 is such that the end portion 102b on the rising mirror 102 side is the end portion of the flange portion 2a of the objective lens 2 on the rising mirror 102 side. It is higher than 2e.

  However, in addition to providing a notch at the end of the lens holder 10, the lens holder 10 is provided so that the lens holder 10 does not cover the rising mirror tip 102 b, and the flange portion of the objective lens 2. Since the D-cut portion 2d is provided in 2a, the lens holder 10 can be stroked toward the pickup base 150 without contacting the objective lens 2 and the rising mirror 102.

(Stroke amount of lens holder 10)
The difference between the stroke amount _{X 2} of the lens holder 10 of the present invention the stroke of _{X 1} of the conventional lens holder 210 shown in FIG. 11 (a) and (b).

11 (a) is a diagram showing the stroke amount _{X 1} of a conventional lens holder 210, FIG. 11 (b) is a diagram showing the stroke amount _{X 1} of the lens holder 10 in the present embodiment.

The rising mirror 302 shown by the solid line in FIG. 11A shows the case where the lens holder 210 is positioned closest to the optical disc, and the rising mirror 302 shown by the broken line is the lens holder 210 most upright. The case where it is located on the raising mirror 210 side is shown. The distance between the raising mirror tip 302b shown in raising mirror tip 302b and the broken line shown in the solid line and the stroke X _1. Moreover, the stroke amount X ₂ is, similarly to the stroke X _1, a distance between the raising mirror tip 102b shown in raising mirror tip 102b and the broken line indicated by the solid line.

The lens holder 10, it is possible to stroke without contacting the rising mirror tip 102b, as shown in FIG. 11 (a) and (b), towards the stroke X ₂ is than the stroke amount X ₁ Also grows. That is, in the optical pickup having the same thickness, the lens holder 10 of the present embodiment can ensure a larger stroke amount than the conventional lens holder 210.

Therefore, only the amount of the difference between the stroke X ₁ and the stroke amount X _2, an optical pickup having a lens drive mechanism 50 can be made thinner.

  Further, the present invention can be used particularly preferably in an optical disc that requires a large working distance because the stroke amount can be ensured without increasing the thickness of the optical pickup.

[Embodiment 2]
An embodiment according to the present invention will be described below with reference to FIGS. 12 (a) to 12 (c) to FIG.

(Configuration of lens holder 10)
In addition, about the member similar to Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Therefore, here, the protrusion 21 will be described below with reference to FIGS.

  12A to 12C are views showing the lens holder 10 according to the second embodiment, where FIG. 12A is a schematic plan view, and FIG. 12B is a schematic cross-sectional view taken along the line PP ′. Yes, (c) is a schematic front view.

  As shown in FIGS. 12B and 12C, a pair of protrusions 21 are provided from the bottom surface of the lens holder 10 facing the pickup base 150 (not shown) toward the pickup base 150.

(Protrusions 21)
The protrusion 21 will be described below with reference to FIG.

  FIG. 13 is a schematic sectional view showing a lens driving mechanism in the second embodiment.

  By providing the protrusion 21, when the lens holder 10 moves in a direction approaching the pickup base 150, the notch 10 d at the end of the lens holder 10, the reflecting surface 102 b of the rising mirror 102, and the protrusion 21. The stroke of the lens holder 10 can be limited by the contact of the pickup base 150 with each other.

  The protrusion 21 can limit the amount of movement of the lens holder 10 when an impact is applied from outside the optical pickup mainly during non-operation.

  Further, the protrusion 21 can limit the movement amount of the lens holder 10 even when an unexpected impact is applied from the outside of the optical pickup during operation. Thus, it is possible to prevent the lens holder 10 from being shaken due to an impact from the outside of the optical pickup and the like, and a good recording / reproducing characteristic cannot be obtained due to a change in the condensing position of the objective lens 2.

  Further, the stroke amount of the lens holder 10 can be arbitrarily adjusted by adjusting the length of the protrusion 21 toward the pickup base 150.

(Additional notes)
The rising mirror 102 may have any shape as long as it can guide the light beam to the objective lens 2.

  The shape of the notches 10b, 15e, 16e, and 17e provided as the optical path of the light beam is not particularly limited as long as it does not block the light beam. As a specific example, a groove or a hole may be used.

The type of the optical disc 1, 1a, and 1b, the optical disc 1, 1a described above as long as an optical disk capable of irradiating a light beam to a predetermined recording / reproducing surface within the scope of the stroke amount X ₂ of the lens holder 10, and It is not limited to 1b.

  The optical pickup of the present embodiment can be mounted on an information recording / reproducing apparatus, for example.

  The present invention has been specifically described above based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims and are different. Embodiments obtained by appropriately combining technical means disclosed in the respective embodiments are also included in the technical scope of the present invention.

  The present invention relates to an optical pickup corresponding to an optical disc that requires a large working distance such as an optical disc that enables high-density recording using a blue laser, and an information recording / reproducing apparatus including the optical pickup. It can be suitably used. Further, the present invention can also be used for an optical pickup corresponding to a special optical disk for recording on the label surface of the optical disk and an information recording / reproducing apparatus including the optical pickup.

It is a figure showing the structure of the lens drive mechanism in the 1st Embodiment of this invention, (a) is a schematic plan view, (b) is a schematic side view, (c) is a schematic front view. It is a figure showing the structure of the optical pick-up in the said embodiment, (a) is a schematic plan view, (b) is a schematic side view. It is a figure showing the structure of the drive part of the lens drive mechanism in the said embodiment, (a) is a schematic plan view, (b) is a schematic arrow sectional drawing which follows a GG 'line, (c ) Is a schematic front view. (A) is a top view showing the lens holder in the said embodiment, (b) is a top view showing the objective lens in the said embodiment, (c) is a schematic side view of this objective lens. . (A) is a top view showing a base, (b) is a schematic front view, (c) is arrow sectional drawing which follows a K-K 'line. (A) is a schematic plan view showing a board | substrate, (b) is a schematic front view, (c) is arrow sectional drawing which follows a M-M 'line. (A) is a schematic plan view showing a wire holder, (b) is a schematic front view, (c) is a cross-sectional view taken along the line O-O ′. 2A and 2B are diagrams illustrating a state of a lens driving mechanism at the time of recording / reproducing of an optical disc in which a recording surface is at a position that is approximately a half of the total thickness, where FIG. is there. It is a figure showing the state of the lens drive mechanism at the time of writing of the optical disk provided with the label surface which can write a figure etc. in the lens holder side, (a) is a schematic sectional drawing, (b) is a schematic side view. is there. It is a figure showing the state of a lens drive mechanism when the optical disk which needs to ensure a large working distance is filled, (a) is a schematic sectional drawing, (b) is a schematic side view. It is a figure which shows the stroke amount of a lens holder, (a) is a figure which shows the stroke amount of the conventional lens holder, (b) is a figure which shows the stroke amount of the lens holder in this Embodiment. It is a figure showing the lens holder in the 2nd Embodiment of this invention, (a) is a schematic plan view, (b) is a schematic arrow sectional drawing which follows a PP 'line, (c) is It is a schematic front view. It is a schematic sectional drawing showing the lens drive mechanism in the 2nd Embodiment of this invention. It is a figure showing the conventional optical pick-up, (a) is a schematic plan view, (b) is a schematic side view. It is a figure showing the conventional lens drive device, (a) is a schematic plan view, (b) is a schematic sectional view taken along the line PP ′, (c) is a schematic rear view, (D) is a schematic side view, (e) is a schematic front view. It is a schematic sectional drawing showing the conventional optical pick-up.

Explanation of symbols

1 Optical disc (optical recording medium)
1a Optical disc (optical recording medium)
1b Optical disc (optical recording medium)
2 Objective lens 2a Head part (protrusion part)
2d D cut part 10 Lens holder (lens holding part)
10b Notch 15 Base 15e Notch 16 Substrate 16e Notch 17 Wire holder 17e Notch 20 Lens drive part 21 Projection part 50 Lens drive mechanism 100 Optical pickup 101 Light beam 102 Rising mirror (mirror)
102a Reflecting surface 102b Rising mirror tip 150 Pickup base

Claims (8)

An objective lens for focusing the light beam on the optical recording medium;
A lens driving mechanism including a lens holding unit that holds the objective lens movably with respect to the optical recording medium,
Light reflected by a mirror having an inclined surface with a reflecting surface facing the lens holding unit is incident on the objective lens as the light beam,
The lens driving mechanism, wherein the lens holding portion is provided so that the end portion faces the mirror, and the end portion of the lens holding portion has a notch portion on the mirror side.   The lens driving mechanism according to claim 1, wherein the notch is formed to be inclined.   The lens driving mechanism according to claim 2, wherein a slope formed on the mirror side at an end of the lens holding portion is parallel to the reflecting surface.   The lens driving mechanism according to claim 1, wherein the objective lens is located at an end of the lens driving mechanism. On the outer periphery of the objective lens, a protrusion for holding the lens holding part is provided in a direction perpendicular to the direction of incidence of the light beam on the objective lens. Protrudes from the holding part,
5. The lens driving mechanism according to claim 1, wherein the protruding portion is cut along a periphery of the lens holding portion from which the protruding portion protrudes. 6.   6. The lens holding portion according to claim 1, wherein an end portion of the lens holding portion is positioned closer to an incident side of the light beam than an end portion of the inclined surface of the mirror on the lens holding portion side. The lens driving mechanism described.   The lens driving mechanism according to claim 1, further comprising an optical path through which the light beam is guided to the objective lens.   An optical pickup comprising the lens driving mechanism according to claim 1.

Images