JP2007213694A - Optical pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device for switching objective lenses by inexpensive constitution in the optical pickup device provided with the plurality of objective lenses so as to be compatible with two or more kinds of optical recording media. <P>SOLUTION: The two objective lenses 9a and 9b provided in the optical pickup device are held by a second holder 24, the second holder 24 is turnably supported by a first holder 15, and the first holder 15 is driven at least in a tracking direction by an actuator 12. When the first holder 15 is moved by a prescribed distance or more in the tracking direction, the second holder 24 is abutted to yokes 16a and 16b, the second holder 24 is turned further, and the objective lenses 9a and 9b are switched. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical pickup apparatus capable of recording information and reading information by irradiating an optical recording medium with a light beam, and more particularly to a structure of an optical pickup apparatus that can handle a plurality of types of optical recording media.

  Optical recording media such as compact discs (hereinafter referred to as CDs) and digital versatile discs (hereinafter referred to as DVDs) are widely used. Further, in recent years, in order to increase the amount of information in an optical recording medium, research on increasing the density of the optical recording medium has been promoted. High-density optical recording media are also being put into practical use.

  In performing recording and reproduction of such an optical recording medium, an optical pickup device that enables recording of information and reading of information by irradiating the optical recording medium with a light beam is used. Depending on the type of the optical recording medium, The numerical aperture (NA) of the objective lens used in the optical pickup device and the wavelength of the light source are different. For example, for CD, the NA of the objective lens is 0.50 and the wavelength of the light source is 780 nm. For DVD, the NA of the objective lens is 0.65, the wavelength of the light source is 650 nm, and for HD-DVD. The objective lens NA is 0.65, the light source wavelength is 405 nm, and for BD, the objective lens NA is 0.85 and the light source wavelength is 405 nm.

  As described above, since the NA and wavelength of the objective lens used are different depending on the type of the optical recording medium, it may be possible to use different optical pickup devices for each optical recording medium. It is convenient to be able to read information about an optical recording medium, and many such optical pickup devices have been developed. Recently, for example, an optical pickup device that can deal with three types of optical recording media such as CD, DVD, and HD-DVD and three types of CD, DVD, and BD with one objective lens has appeared.

  However, in the case of a configuration in which a single objective lens is used in an optical pickup device that supports a plurality of types of optical recording media, in general, the design of the objective lens becomes difficult and expensive. For example, in an optical pickup device corresponding to four types of CD, DVD, HD-DVD, and BD, the design of the objective lens becomes very difficult, and even if it can be manufactured, it becomes a very expensive objective lens. For this reason, in particular, when manufacturing an optical pickup device that reads information on four or more types of optical recording media, it is currently a good idea to arrange two or more objective lenses in the optical system. It is.

  In this regard, there have been various reports on a configuration in which a plurality of objective lenses are arranged in an optical system of an optical pickup device. For example, in Patent Document 1, a lens composed of four aspheric surfaces each facing two aspheric surfaces is used, and a pair of two aspheric surfaces facing each other is used as an objective lens. An optical pickup device having a structure that is rotated by using is introduced.

  Further, Patent Document 2 includes two objective lens actuators each mounting one objective lens, and switching means for sliding the two objective lens actuators to insert / remove the objective lens into / from the optical path. An optical pickup device having a configuration is introduced.

  However, in the case of the optical pickup devices introduced in Patent Document 1 and Patent Document 2, since the dedicated actuator is provided for switching a plurality of objective lenses, the number of expensive parts increases. There is a problem that costs increase. In addition, an optical pickup device having a configuration in which an actuator is attached to a so-called rising mirror (total reflection mirror) and the optical path of a light beam emitted from the light source by the actuator is switched to switch a plurality of objective lenses can be used. Even in this case, an actuator for moving the rising mirror is required separately, and there is a problem of an increase in cost due to an increase in the number of expensive parts.

Further, an optical pickup device having a configuration in which a plurality of objective lenses are arranged on the movable portion of the shaft-sliding biaxial actuator and the objective lens is switched by rotating the movable portion is also conceivable. In this case, since there is no need to provide a separate dedicated actuator, there is no problem with an increase in the number of expensive parts. However, the shaft-sliding type biaxial actuator is expected to become a mainstream in the future such as HD-DVD and BD. In order to record / reproduce HD-DVD, BD, etc. because it does not have a tilt function for tilting the objective lens, which is generally considered necessary for recording / reproducing information on a high-density optical recording medium. It is not sufficient as an optical pickup device to be used.
JP 2000-182272 A JP-A-9-54961

  In view of the above problems, an object of the present invention is to provide an optical pickup device having a plurality of objective lenses so as to be compatible with a plurality of types of optical recording media, and capable of switching the objective lenses with an inexpensive configuration. Is to provide. Another object of the present invention is to provide an optical pickup device that can cope with high-density optical recording media such as HD-DVD and BD while achieving the above-mentioned object.

  In order to achieve the above object, the present invention provides a plurality of light sources having different wavelengths, an objective lens for condensing a light beam emitted from the light source on a recording surface of an optical recording medium, and a first lens mounted with the objective lens. In the optical pickup device, comprising: one holder, and an actuator that can move the objective lens in at least a tracking direction that is a radial direction of the optical recording medium by driving the first holder. A plurality of objective lenses are mounted on the first holder, and the first holder is arranged in the optical path of the light beam from among the plurality of objective lenses by moving the first holder in the tracking direction. It is characterized in that the objective lens can be selectively switched.

  According to the present invention, in the optical pickup device having the above configuration, the first holder is mounted with a second holder for holding the plurality of objective lenses, and both sides of the second holder in the tracking direction are mounted. Is provided with a fixing member that is fixedly arranged and comes into contact with the second holder when the first holder moves in the tracking direction by a predetermined distance or more, and the second holder includes the first holder. After the second holder is brought into contact with the fixing member after the holder is moved in the tracking direction, the holder is provided so as to move when the first holder continues to move in the same direction.

  Further, the present invention is characterized in that, in the optical pickup device having the above-described configuration, the second holder is rotatably supported by the first holder and rotates after contacting the fixing member. .

  In the optical pickup device having the above configuration, the first holder and the second holder may be paired with the second holder when the second holder is not in contact with the fixing member. A locking portion for fixing the second holder to the first holder is provided.

  According to the present invention, in the optical pickup device configured as described above, the actuator includes a base and a yoke for standing from the base to form a magnetic path, and the yoke is used as the fixing member. It is characterized by being able to.

  According to the present invention, in the optical pickup device having the above-described configuration, the actuator drives the first holder to move the objective lens in a focus direction that is perpendicular to the recording surface, and the tracking direction. It is possible to move in a tilt direction which is a direction around an axis orthogonal to the focus direction.

  According to the first configuration of the present invention, in an optical pickup device including a plurality of objective lenses, the objective lens arranged in the optical path can be switched without providing a dedicated actuator. For this reason, about an optical pick-up apparatus provided with a some objective lens, an inexpensive optical pick-up apparatus can be provided, without increasing the number of expensive components like an actuator.

  Further, according to the second configuration of the present invention, in the optical pickup device having the first configuration, an optical pickup device capable of switching an objective lens without using a dedicated actuator can be easily realized.

  According to the third configuration of the present invention, in the optical pickup device having the second configuration, the size of the second holder that holds the objective lens can be made compact, and the burden on the actuator can be reduced. Become. Further, the optical pickup device can be configured not to increase in size.

  According to the fourth configuration of the present invention, in the optical pickup device having the second or third configuration, the objective lens disposed in the optical path can be fixed so as not to move during recording / reproduction of the optical recording medium. Therefore, it is possible to suppress deterioration in quality in information recording / reproduction by the optical pickup device.

  Further, according to the fifth configuration of the present invention, in the optical pickup device having any one of the second to fourth configurations, it is possible to prevent an increase in the number of extra parts and an increase in the size of the actuator.

  Further, according to the sixth configuration of the present invention, the optical pickup device having any one of the first to fifth configurations has a high quality even for high-density optical recording media such as HD-DVD and BD. An optical pickup capable of recording and reproducing can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, embodiment shown here is an example and this invention is not limited to embodiment shown here.

  FIG. 1 is a schematic diagram showing an optical system of the optical pickup device of the present embodiment. In FIG. 1, reference numeral 1 denotes an optical pickup device, which irradiates a light beam to four types of optical recording media 11 of CD, DVD, HD-DVD, and BD, and receives the reflected light. This is an apparatus that can read information recorded on the recording surface 11a and write information on the recording surface 11a by irradiating the optical recording medium 11 with a light beam. The optical system of the optical pickup device 1 includes, for example, a first light source 2, a second light source 3, a dichroic prism 4, a beam splitter 5, a collimator lens 6, a rising mirror 7, a liquid crystal element 8, An objective lens 9 and a photodetector 10 are provided. Details of each optical element will be described below.

  The first light source 2 is a two-wavelength one-package type semiconductor laser, and can emit a light beam having a wavelength of 780 nm band corresponding to CD and a light beam having a wavelength of 650 nm band corresponding to DVD. The second light source 3 is a semiconductor laser that can emit a light beam having a wavelength of 405 nm band corresponding to HD-DVD and BD. The arrangement of the light sources is not limited to the configuration of the present embodiment, and various changes can be made without departing from the object of the present invention. That is, a light source that emits a light beam for CD and DVD may be configured to emit light from different semiconductor lasers, or a semiconductor laser that can emit light beams of three types in one package. A configuration to be used may be used.

  The dichroic prism 4 transmits the light beam emitted from the first light source 2 and reflects the light beam emitted from the second light source 3. Then, the optical axes of the light beams emitted from the first light source 2 and the second light source 3 are matched. The light beam transmitted or reflected by the dichroic prism 4 is sent to the beam splitter 5.

  The beam splitter 5 functions as a separation element that separates the light beam, and transmits the light beams emitted from the first and second light sources 2 and 3 to the optical recording medium 11 side. The reflected light is reflected and guided to the photodetector 10. The light beam that has passed through the beam splitter 5 is sent to the collimating lens 6.

  The collimating lens 6 is a lens that converts the light beam transmitted through the beam splitter 5 into parallel light. Here, the parallel light means light in which all optical paths of the light beams emitted from the first and second light sources 2 and 3 are substantially parallel to the optical axis. The parallel light transmitted through the collimating lens 6 is sent to the raising mirror 7.

  The rising mirror 7 reflects the light beam transmitted through the collimating lens 6 and guides it to the optical recording medium 11. The rising mirror 7 is inclined by 45 ° with respect to the optical axis of the light beam from the collimating lens 6, and the optical axis of the light beam reflected by the rising mirror 7 is recorded on the optical recording medium 11. It is substantially orthogonal to the surface 11a. The light beam reflected by the rising mirror 7 is sent to the liquid crystal element 8.

  The liquid crystal element 8 applies a voltage to a liquid crystal sandwiched between transparent electrodes (both not shown), and controls the change in the refractive index by utilizing the property that the liquid crystal molecules change the orientation direction thereof. This element enables control of the phase of the light beam transmitted through the element 8. The recording surface 11a of the optical recording medium 11 is covered with a protective layer 11b. The thickness of the protective layer 11b varies depending on the type of the optical recording medium 11 (for example, 1.2 mm for CD, DVD and HD-DVD). 0.6 mm and BD 0.1 mm). And spherical aberration arises from the difference in the thickness of this protective layer 11b. The liquid crystal element 8 is provided to correct this spherical aberration. The light beam that has passed through the liquid crystal element 8 is sent to the objective lens 9.

  In the optical system of the optical pickup device 1 of the present embodiment, the liquid crystal element 8 is disposed. However, the configuration is not necessarily limited to this configuration, and the liquid crystal element 8 is not disposed in the optical system depending on the configuration of the optical system. It does not matter. In the present embodiment, the liquid crystal element 8 is arranged as means for correcting the spherical aberration. However, the present invention is not limited to this, and an aberration correcting element such as an expander lens may be arranged.

  The objective lens 9 condenses the light beam transmitted through the liquid crystal element 8 on the recording surface 11 a of the optical recording medium 11. In FIG. 1, only one objective lens 9 is shown for convenience, but the optical pickup device 1 is provided with two objective lenses 9, and optical recording is performed using the optical pickup device 1 for recording and reproduction. The objective lens 9 to be used is selectively switched depending on the type of the medium 11. The two objective lenses 9 used in the present embodiment are used, for example, when one of them performs CD / DVD / HD-DVD recording / reproduction, and when the other performs BD recording / reproduction. Designed. These two objective lenses 9 are mounted on an actuator and configured to be movable in a predetermined direction. The configuration of the actuator and the configuration for switching the two objective lenses 9 will be described in detail later.

  The reflected light reflected by the optical recording medium 11 passes through the objective lens 9 and the liquid crystal element 8, is reflected by the rising mirror 7, is reflected by the beam splitter 5 after passing through the collimating lens 6, and is detected by the photodetector 10. To the light receiving part (not shown).

  The photodetector 10 converts the received optical information into an electrical signal and outputs it to, for example, an RF amplifier (not shown). This electric signal is used as a reproduction signal for reproducing data recorded on the recording surface 11a, and further for servo control such as a focus error signal and a track error signal for performing focus control and tracking control. Used as a signal.

  Next, the configuration of the actuator on which the objective lens 9 is mounted will be described with reference to FIGS. Here, FIG. 2 is a schematic plan view of the actuator 12 of the present embodiment as viewed from above, FIG. 3 is a schematic side view of the actuator 12 of the present embodiment as viewed from the right side of FIG. 2, and FIG. It is AA sectional drawing.

  The actuator 12 is mainly composed of a metallic base member 13 having ferromagnetism and a first holder 15 that is a resin molded product. The base member 13 is formed with a through hole (not shown) through which a light beam emitted from the first light source 2 or the second light source 3 (see FIG. 1) passes, and a first hole which will be described in detail later. A holder 15 is arranged. In addition, a pair of permanent magnets 14 a and 14 b that are opposed to each other at a predetermined interval are provided on the base member 13 so as to sandwich the first holder 15. The permanent magnets 14 a and 14 b are fixed in a state where they are magnetically integrated with the base member 13 by being magnetically attached to the protruding pieces 13 a and 13 b that are bent from the base member 13.

  Further, the base member 13 is provided with a pair of yokes 16a and 16b that are opposed to each other in a direction substantially perpendicular to the facing direction of the permanent magnets 14a and 14b between the permanent magnets 14a and 14b. Each of these yokes 16 a and 16 b is formed by bending from the base member 13. Here, each of the yokes 16a and 16b forms a magnetic path, and specifically, a focusing coil described later that mainly draws magnetic flux from the permanent magnets 14a and 14b and is mainly disposed between the two. 17, a high-density magnetic flux is applied to the tracking coils 18a and 18b and the tilt coils 23a and 23b, thereby playing a role of increasing the driving efficiency of the first holder 15.

  The first holder 15 is formed in a hollow shape, and is arranged so that the optical axis of the light beam emitted from the light sources 2 and 3 passes through substantially the center thereof. The first holder 15 includes two objective lenses 9a and 9b held by the second holder 24. The two objective lenses 9a and 9b held by the second holder 24 can be switched and used as necessary. When the switching is completed, either one of the objective lenses 9a and 9b can be used. The optical axis coincides with the optical axis of the light beam emitted from the light sources 2 and 3. In FIG. 2, the optical axis of the objective lens 9 a coincides with the optical axis of the light beam emitted from the light sources 2 and 3. Further, the yokes 16 a and 16 b are located in the hollow of the first holder 15 so as to sandwich the second holder 24. Details of the second holder 24 will be described later.

  A focusing coil 17 wound in a substantially rectangular shape is provided inside the side wall of the first holder 15, and is fixed to the first holder 15 with an adhesive or the like. Also, tracking coils 18a and 18b are respectively fixed to the outer sides of the side walls of the first holder 15 facing the permanent magnets 14a and 14b with an adhesive or the like. Each of the tracking coils 18a and 18b is formed as a pair (see FIG. 2) on the left and right so as to face each other with the yokes 16a and 16b interposed therebetween, and is connected by a single line as a whole. Further, tilt coils 23a and 23b are fixed to the lower portion of the focus coil 17 with an adhesive or the like so as to surround the yokes 16a and 16b. The tilt coils 23a and 23b are also connected by a single line as a whole.

  On the base member 13, a gel holder 19 of a resin molded product such as polycarbonate is fixed on the outer surface side of the projecting piece 13 b on which one permanent magnet 14 b is magnetized, and a circuit is provided adjacent to the outside of the gel holder 19. A substrate 21 is erected. The circuit board 21 is soldered with one end of each of the conductive wires 20a, 20b, 20c, 20d, 20e, and 20f on three sides in the vertical direction on both the left and right sides (see FIGS. 2 and 3). Connected. Each of these six wires 20a to 20f has through-holes 22a, 22b, and 22c formed in the gel holder 19 at three positions in the vertical direction at positions corresponding to the connection positions to the circuit board 21, that is, both left and right sides. , 22d, 22e, and 22f are inserted.

  Further, the wires 20a to 20f are joined to the protrusions 15a and 15b projecting from the left and right sides of the first holder 15 with an adhesive or the like, so that the first holder 15 is made into a base by the wires 20a to 20f. The member 13 is swingably supported. The other ends of the upper wires 20a and 20d are connected to the focusing coil 17 by soldering, and the other ends of the middle wires 20b and 20e are connected to the tracking coils 18a and 18b by soldering. The other ends of the lower wires 20c and 20f are connected to the tilt coils 23a and 23b by soldering.

  Moreover, the gel material which has silicon as a main component is filled in each through-hole 22a-22f of the gel holder 19 by which each wire 20a-20f was penetrated. Here, the gel material is obtained by injecting a low-viscosity gel material (sol) into each of the through holes 22a to 22f of the gel holder 19 and then curing the gel material by ultraviolet irradiation for a predetermined time. The gel holder 19 serves to attenuate and suppress vibration generated in the wires 20a to 20f by the gel material in accordance with the driving of the first holder 15.

  In the actuator 12 configured as described above, when current is supplied from the circuit board 21 to the focusing coil 17 through the wires 20a and 20d, the base member 13, the permanent magnets 14a and 14b, and the yokes 16a and 16b are formed. Due to the electromagnetic action with the magnetic circuit (magnetic path), the first holder 15 is driven in the focus direction which is the vertical direction in FIG. 3 (the paper surface direction in FIG. 2). Therefore, the position of the objective lenses 9a and 9b in the focus direction can be adjusted by adjusting the magnitude and direction of the current supplied to the focus coil 17.

  Further, when a current is supplied from the circuit board 21 to the tracking coils 18a and 18b through the wires 20b and 20e, an electromagnetic connection with the magnetic circuit formed by the base member 13, the permanent magnets 14a and 14b, and the yokes 16a and 16b is performed. Due to this action, the first holder 15 is driven in the tracking direction which is the left-right direction in FIG. Therefore, the position of the objective lenses 9a, 9b in the tracking direction (radial direction of the optical recording medium 11) can be adjusted by adjusting the magnitude and direction of the current supplied to the tracking coils 18a, 18b.

  Further, when current is supplied from the circuit board 21 to the coils for tilting 23a and 23b through the wires 20c and 20f, the circuit is electromagnetically connected to the magnetic circuit formed by the base member 13, the permanent magnets 14a and 14b, and the yokes 16a and 16b. Due to this action, the first holder 15 is driven in the tilt direction, which is the direction around the axis orthogonal to both the focus direction and the tracking direction. Therefore, the position of the objective lenses 9a and 9b in the tilt direction can be adjusted by adjusting the magnitude and direction of the current supplied to the tilt coils 23a and 23b.

  Next, the configuration of the second holder 24 that holds the two objective lenses 9 a and 9 b and the operation in which the objective lenses 9 a and 9 b held by the second holder 24 are switched according to the type of the optical recording medium 11. Will be described. FIG. 5 is a diagram for explaining the configuration of the second holder 24 of the present embodiment, and FIG. 5A is a schematic diagram showing a state before the second holder 24 is mounted on the first holder 15. FIG. 5B is a schematic perspective view showing a state in which the second holder 24 is mounted on the first holder 15.

  As shown in FIG. 5A, the second holder 24 is formed in a pentagonal prism shape in which a surface 24a parallel to the tracking direction (direction indicated by an arrow in the figure) is a pentagon. The objective lenses 9a and 9b are held on two adjacent surfaces of the side surface of the pentagonal prism, respectively. The pentagonal columnar second holder 24 is hollow, and the surface 24c side facing the side 24b that is the boundary of the surface on which the objective lenses 9a and 9b are mounted is open and emitted from the light sources 2 and 3. The light beam is configured to be incident on the objective lenses 9a and 9b. In addition, two pentagonal surfaces 24a of the second holder 24 are respectively opposed to the rotary shaft 26 that rotatably supports the second holder 24, and the second holder 24 is the first holder. And convex portions 25 a and 25 b that are used for fixing to 15.

  As shown in FIG. 5B, the rotation shaft 26 of the second holder 24 is a position where two surfaces 15a parallel to the tracking direction of the first holder 15 face each other, and is provided on the lower center side. It fits into the hole 27. Further, the second holder 24 mounted on the first holder 15 needs to be fixed to the first holder 15 except when the objective lenses 9a and 9b are switched. Yes, in the present embodiment, either the convex portion 25a provided on the second holder 24 or the convex portion 25b is fitted into the fixing hole 28 provided on the center upper side of the surface 15a of the first holder 15. The second holder 24 is fixed by being stuck.

  That is, the protrusions 25 a and 25 b provided on the second holder 24 and the fixing hole 28 provided on the first holder 15 are paired to fix the second holder 24 to the first holder 15. It functions as a stop part 29. In addition, the structure of this latching | locking part 29 is not the meaning limited to the structure of this embodiment, A various change is possible. That is, for example, the first holder 15 may be provided with a convex portion and the second holder may be provided with a hole.

  In a state where the second holder 24 is fixed to the first holder 15, the optical axis of one of the objective lenses 9 a and 9 b held by the second holder 24 is emitted from the light sources 2 and 3. The convex portions 25a and 25b of the second holder 24 are formed so as to coincide with the optical axis of the light beam. In FIG. 5B, the objective lens 9a is disposed in the optical path of the optical pickup device in a state where the optical axis of the objective lens 9a coincides with the optical axis of the light beam emitted from the light sources 2 and 3. .

  Next, the switching operation of the objective lenses 9a and 9b mounted on the second holder 24 will be described. FIG. 6 is a diagram for explaining an operation of switching the objective lens arranged in the optical path of the optical pickup device 1 from the objective lens 9a to the objective lens 9b. When an instruction to switch the objective lenses 9a and 9b is instructed to the actuator 12 by a control unit (not shown) according to the type of the optical recording medium 11 that records and reproduces information using the optical pickup device 1, the actuator 12 The first holder 15 is moved in any one of the tracking directions corresponding to the left-right direction in FIG. FIG. 6 shows a state in which the first holder 15 is moved in the left direction.

  Then, when the first holder 15 performs recording / reproduction using the optical pickup device 1, if the actuator 12 is moved by a predetermined distance longer than the distance by which the first holder 15 is moved for tracking adjustment, 2 holder 24 comes into contact with the yoke 16b (see FIG. 2) (state shown in FIG. 6A). Then, after the second holder 24 comes into contact with the yoke 16b, if the first holder 15 is further moved leftward, a rightward force is applied to the second holder 24, and the convex portion 25a becomes the first portion 25a. 3 is removed from the fixing hole 28 (see FIG. 5) provided in the holder 15 and starts rotating in the direction of the arrow R in the figure around the rotation shaft 26.

  Further, when the first holder 15 is continuously moved in the left direction in the drawing, the convex portion 25b of the second holder 24 is fitted in the fixing hole 28 of the first holder 15 (FIG. 6B). ) State). At this time, the driving of the first holder 15 in the tracking direction is stopped, the first holder 15 returns to the original position, and the switching from the objective lens 9a to the objective lens 9b is completed. Further, when an instruction to switch from the objective lens 9b to the objective lens 9a is transmitted to the actuator 12, the first holder 15 is moved in the direction opposite to that in the case of FIG. 6, and the same switching is performed.

  Although the second holder 24 of the present embodiment is configured to rotate by contacting the yokes 16a and 16b, a fixing member is disposed separately from the yokes 16a and 16b, and the fixing member and the second The second holder 24 may be rotated by the contact of the holder 24. However, it is preferable to use the yokes 16a and 16b because space can be used effectively and the size of the apparatus can be reduced. In addition, the portion where the second holder 24 and the yokes 16a and 16b abut may be in various positions depending on the purpose and the like, but the yokes 16a and 16b abut on the lower side of the second holder 24. Such a configuration has an advantage that the range in which the second holder 24 can move before contacting the yokes 16a and 16b is increased.

  In the present embodiment, the second holder 24 and the yokes 16a and 16b are in contact with each other only by moving the first holder 15 in the tracking direction. Of the second holder 24 and the yokes 16a, 16b, etc. when the first holder 15 is moved in the tracking direction after the first holder 15 has moved in a direction away from the optical recording medium 11. A configuration in which the fixing member abuts may be employed.

  In the present embodiment described above, the shape of the second holder 24 is a pentagonal prism shape. However, the present invention is not limited to this configuration, and various modifications can be made without departing from the object of the present invention. However, in this case, it is necessary to form the second holder 24 so that the objective lens does not contact the yoke or the fixing member. Further, by changing the shape of the second holder 24, it is possible to switch not only two objective lenses but also three or more objective lenses. In addition, the second holder 24 is not configured to hold a plurality of objective lenses, but the second holder is divided into a plurality of holders, and one or more objective lenses are held for each of the holders. A configuration for switching may be used.

  Furthermore, in the present embodiment, the objective lenses 9a and 9b are switched by rotating the second holder 24. However, the present invention is not limited to this and can be changed without departing from the object of the present invention. is there. That is, for example, as shown in FIG. 7, by mounting two objective lenses on the second holder 24 that is a rectangular parallelepiped and supporting the second holder 24 slidably with respect to the first holder 15, A configuration in which the objective lens is switched in accordance with the movement of one holder 15 in the tracking direction may be employed. 7A is a schematic plan view of the first holder 15 and the second holder 24 viewed from above, and FIG. 7B is a schematic plan view of the second holder 24 viewed from the side. is there.

  In the configuration of FIG. 7, the second holder 24 is slidably supported on a support base 30 formed on the first holder 15, and when switching from the objective lens 9a to the configuration of the objective lens 9b, The first holder 15 is moved in the left direction which is one of the tracking directions which are the left and right directions in the figure. When the second holder 24 comes into contact with the yoke 16 b and further moves the first holder 15 to the left, the convex portion 25 a of the second holder 24 is provided in the fixing hole 28 provided in the first holder 15. The fixing hole 28 and the convex portion 25b of the second holder 24 are fitted. Thereby, switching from the objective lens 9a to the objective lens 9b is performed. In this configuration, three or more objective lenses may be arranged.

  In addition, in the optical pickup device 1 of the present embodiment, the actuator 12 is configured to drive the first holder 15 in three directions of the focus direction, the tracking direction, and the tilt direction. The present invention can be applied to an actuator having a configuration different from that of the present embodiment as long as 12 is configured to move at least in the tracking direction. Further, the type and number of optical recording media that can be recorded and reproduced by the optical pickup device are not limited to those of the present embodiment, and it goes without saying that various changes can be made.

  According to the present invention, in an optical pickup device that has a plurality of objective lenses that condense a light beam from a light source onto a recording surface of an optical recording medium and uses a plurality of objective lenses, the switching of the objective lenses is performed. Since this can be achieved by using an actuator that drives the objective lens without separately providing a dedicated actuator, the optical pickup device can be manufactured at low cost.

  In addition, according to the present invention, the objective lens actuator that also switches a plurality of objective lenses can be easily configured as an actuator that moves the objective lens in three directions of the focus direction, tracking direction, and tilt direction. It is easy to apply as an optical pickup device corresponding to BD and HD-DVD, which generally requires the objective lens to be driven in the tilt direction during recording and reproduction.

These are the schematic which shows the structure of the optical system of the optical pick-up apparatus in this embodiment. These are the schematic top views which show the structure of the actuator of this embodiment. These are the schematic side views which show the structure of the actuator of this embodiment. These are AA sectional drawing of FIG. These are explanatory drawings for demonstrating the structure of the 2nd holder of this embodiment. These are the figures for demonstrating the switching operation | movement of an objective lens in the structure of this embodiment. These are the modifications of the structure of the 2nd holder which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical pick-up apparatus 2 1st light source 3 2nd light source 9, 9a, 9b Objective lens 11 Optical recording medium 11a Recording surface 12 Actuator 15 1st holder 16a, 16b Yoke (fixing member)
24 Second holder 29 Locking portion

Claims (6)

A plurality of light sources having different wavelengths, an objective lens for condensing a light beam emitted from the light source on a recording surface of an optical recording medium, and a first holder on which the objective lens is mounted. In an optical pickup device comprising: an actuator capable of moving the objective lens in at least a tracking direction which is a radial direction of the optical recording medium by driving
A plurality of objective lenses are mounted on the first holder,
An optical pickup characterized in that, by moving the first holder in the tracking direction, the objective lens arranged in the optical path of the light beam can be selectively switched from among the plurality of objective lenses. apparatus. A second holder for holding the plurality of objective lenses is mounted on the first holder,
Fixing members that are fixedly disposed on both sides of the second holder in the tracking direction so as to come into contact with the second holder when the first holder moves a predetermined distance or more in the tracking direction are provided. ,
The second holder moves when the first holder is moved in the tracking direction and the second holder is in contact with the fixing member, and then further moved in the same direction. The optical pickup device according to claim 1, wherein the optical pickup device is provided as follows.   3. The optical pickup device according to claim 2, wherein the second holder is rotatably supported by the first holder and rotates after contacting the fixing member. 4.   The first holder and the second holder are paired to fix the second holder to the first holder when the second holder is not in contact with the fixing member. The optical pickup device according to claim 2, wherein a locking portion is provided.   5. The actuator according to claim 2, wherein the actuator includes a base and a yoke for standing from the base to form a magnetic path, and the yoke is used as the fixing member. The optical pick-up apparatus of any one of them.   The actuator drives the first holder to move the objective lens around an axis that is orthogonal to the focus direction, which is a direction orthogonal to the recording surface, and to both the tracking direction and the focus direction. The optical pickup device according to any one of claims 1 to 5, wherein the optical pickup device is movable in a tilt direction that is a direction.