JP2009140561A - Optical pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device having a structure that easily and properly performs adjustment of wave front aberration when manufactured, in the optical pickup device having a plurality of optical systems used selectively depending on the kind of optical recording medium. <P>SOLUTION: The optical pickup device 1 has two optical systems which guide light emitted from a light source to an optical recording medium and which guide the light reflected by the optical recording medium to a light receiving part. In one of the optical systems out of two optical systems, an optical member which is not mounted on an objective lens actuator out of optical members constituting the optical system is made into a unit together with the optical source 21 and mounted on a base 2. Also, in two objective lenses possessed by each optical system, directions of coma aberration possessed by them are aligned in the same direction, and the two objective lenses are mounted on the lens holder of the objective lens actuator. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical pickup apparatus that reads and writes information by irradiating light onto an optical recording medium, and more specifically, an optical pickup having a plurality of optical systems that are selectively used depending on the type of optical recording medium. It relates to the configuration of the apparatus.

  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, research for increasing the amount of information recorded on an optical recording medium has been advanced, and optical recording media such as HD-DVD and Blu-ray disc (hereinafter referred to as BD) have been put into practical use. Such reading of information from the optical recording medium and writing of information to the optical recording medium are performed using an optical pickup device.

  In an optical pickup device, if the type of optical recording medium to be read or written of information is different, the numerical aperture (NA) of the objective lens or the wavelength of the light source may need to be different. For example, for CD, the NA of the objective lens is 0.45, 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 BD, The NA of the objective lens is 0.85 and the wavelength of the light source is 405 nm. The objective lens here refers to a lens for condensing the light emitted from the light source on the information recording surface of the optical recording medium.

  As described above, since the NA of the objective lens and the wavelength of the light source may need to be different depending on the type of the optical recording medium, it is possible to use different optical pickup devices depending on the type of the optical recording medium. It is done. However, if different optical pickup devices are used depending on the type of optical recording medium, there is a disadvantage in terms of cost. For this reason, an optical pickup device that can read and write information on a plurality of types of optical recording media with one optical pickup device has been developed.

  In an optical pickup device corresponding to a plurality of types of optical recording media, an optical system that guides light emitted from a light source to an information recording surface of the optical recording medium and guides light reflected by the optical recording medium to a light receiving unit. There is a configuration in which a plurality of systems are used, and an optical system to be used is properly used depending on the type of optical recording medium to be read or written (for example, refer to Patent Documents 1 and 2).

  In the optical pickup device disclosed in Patent Document 1, the biaxial actuator that drives and adjusts the objective lens in the biaxial direction is unitized (in Patent Document 1, the united biaxial actuator is referred to as a biaxial block). In other words, a different biaxial block is provided for each optical system. In the case of such a configuration, the number of biaxial blocks increases as the number of optical systems increases, so that there is a problem that the optical pickup device is enlarged.

In this regard, in the optical pickup device of Patent Document 2, even if two objective lenses are mounted on one lens holder and the number of optical systems is two, the number of biaxial actuators mounting the objective lenses is one. It is said. For this reason, even when the number of optical systems is two, the enlargement of the optical pickup device can be suppressed.
Japanese Patent Laid-Open No. 11-185267 JP 2000-48373 A

  However, the optical pickup device configured as disclosed in Patent Document 2 has the following problems.

  In the optical pickup device of this configuration, even if the wavefront aberration (coma aberration or astigmatism) is adjusted to be optimal for one of the two objective lenses, the wavefront aberration may occur on the other. is there. In consideration of such points, the optical pickup device of Patent Document 2 is configured such that at least one of the two objective lenses is tilt-adjusted and fixed to the lens holder. When adjusting the tilt of the objective lens, a reference light source prepared separately is used instead of the light source mounted on the optical pickup device.

  However, in this case, the same conditions may not be satisfied for the reference light source and the light source actually mounted on the optical pickup device, and the wavefront aberration may not be sufficiently suppressed. In this regard, it is sufficient to adjust the tilt of the objective lens using a light source that is actually mounted on the optical pickup device. However, there is a problem that the work is difficult because there is not enough space for the adjustment. In addition, the adjustment of the tilt of the objective lens mounted on the lens holder involves adjusting the angle of a very small component, so that there is a problem that workability is poor in that sense.

  In view of the above points, an object of the present invention is to easily and appropriately adjust the wavefront aberration at the time of manufacture in an optical pickup device having a plurality of optical systems that are selectively used depending on the type of optical recording medium. An object of the present invention is to provide an optical pickup device having a structure that can be used.

  In order to achieve the above object, the present invention is an optical pickup device having a plurality of optical systems that guide light emitted from a light source to an optical recording medium and guide light reflected by the optical recording medium to a light receiving unit. An objective lens that is included in each of the plurality of optical systems and that condenses light emitted from the light source onto an information recording surface of the optical recording medium; and a base on which the plurality of optical systems are mounted. An actuator mounted on the base for holding all of the plurality of objective lenses, and an actuator for moving the objective lens by moving the lens holder, In each of the optical systems except one of them, an optical member that is not mounted on the actuator among the optical members constituting the optical system is unitized together with the light source to form the base. Is mounted on the scan, a plurality of the objective lens is characterized in that the direction of the coma aberration, each with is mounted on the lens holder is aligned in the same direction.

  According to this, some light sources and optical systems mounted in the optical pickup device are configured as a unit, and the wavefront aberration can be adjusted by moving the unitized portion when manufacturing the optical pickup device. In addition, the plurality of objective lenses mounted on the optical pickup device are configured to be mounted on the actuator with their coma aberration directions aligned in the same direction. For this reason, the coma aberration can be suppressed for the other optical systems by adjusting the coma aberration at the time of manufacturing the optical pickup device so as to be the best for one optical system. Further, in this optical pickup device, it is possible to adjust the wavefront aberration at the time of manufacture using light emitted from a light source mounted on the optical pickup device.

  Further, in the optical pickup device having the above configuration according to the present invention, the optical system includes a mirror that reflects light emitted from the light source and directs the light in a direction orthogonal to the information recording surface. The optical member unitized with the light source in the optical system includes the mirror, an optical member disposed while light emitted from the light source reaches the mirror, and light reflected by the optical recording medium. It is good also as an optical member arrange | positioned between the said mirror and the said light-receiving part.

  In the optical pickup device having the above configuration according to the present invention, the number of the optical systems may be two. Of the two optical systems, one is an optical system used for an optical recording medium according to the BD standard, and the other is an optical system used for an optical recording medium according to the CD standard and the DVD standard. It is good also as being.

  According to the present invention, in an optical pickup device having a plurality of optical systems that are selectively used according to the type of optical recording medium, the optical pickup device has a structure capable of easily and appropriately adjusting the wavefront aberration during manufacturing. Can provide.

  Hereinafter, embodiments of an optical pickup device of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic plan view of the optical pickup device of this embodiment as viewed from above. FIG. 2 is a schematic plan view of the optical pickup device of this embodiment as viewed from below. In addition, although a metal cover is actually attached to the lower surface side of the optical pickup device 1 of the present embodiment, FIG. 2 shows a state where the metal cover is removed for convenience of explanation.

  The optical pickup apparatus according to the present embodiment includes an optical recording medium that conforms to the BD standard (sometimes simply expressed as BD), an optical recording medium that conforms to the DVD standard (sometimes simply expressed as DVD), and an optical recording medium that conforms to the CD standard. (It may be simply expressed as a CD), so that information can be read and information can be written. When information is read or written by the optical pickup device 1, the optical recording medium is arranged on the front side of the sheet with reference to FIG.

  As shown in FIGS. 1 and 2, the optical pickup device 1 of the present embodiment includes a slide base 2 on which various optical members, an objective lens actuator 30, and the like described later are mounted. The slide base 2 is formed of resin and has guide bar holding portions 1a and 1b so that the optical pickup device 1 can slide along two guide bars (not shown) arranged in parallel. Yes.

  The guide bar holding portion 1a has two through-holes (not shown) and is opposed to each other. The guide bar holding part 1a can slide one guide bar that passes through the two through-holes. Hold on. The guide bar holding portion 1b is formed in a substantially U shape in a sectional view and holds one guide bar so as to be slidable.

  The optical pickup device 1 of the present embodiment has two optical systems that guide light emitted from the light source to the optical recording medium and guide light reflected by the optical recording medium to the light receiving unit. Specifically, the optical pickup device 1 has two optical systems, an optical system for BD and an optical system for DVD / CD (DVD and CD), and these two optical systems are selectively used. used. These two optical systems will be described with reference mainly to FIGS.

  First, an optical system for BD will be described. The BD optical system guides the laser light emitted from the first laser diode 11 to the optical recording medium and guides the reflected light reflected by the optical recording medium to the first photodetector 19. The BD optical system includes a diffraction element 12, a polarizing beam splitter 13, a first collimating lens 14, a quarter-wave plate 15, a first raising mirror 16, a first objective lens 17, and a first objective lens 17. And a cylindrical lens 18.

  The first laser diode 11 is a light source that emits laser light having a wavelength of 405 nm. The first photodetector 19 is a light receiving unit that converts an incident optical signal into an electrical signal and outputs the electrical signal. The electrical signal output from the first photodetector 19 is processed by a signal processing unit (not shown) to become a reproduction signal, a focus error signal, a tracking error signal, and the like.

  Laser light emitted from the first laser diode 11 is incident on a diffraction element 12 on which a predetermined diffraction grating is formed, and is divided into a main beam and two sub beams. Laser light emitted from the diffraction element 12 is reflected by the polarization beam splitter 13 and sent to the first collimating lens 14.

  The first collimating lens 14 can be moved in the optical axis direction (the direction of the arrow shown in FIG. 2) by the collimating lens driving means 20, and is incident on the first objective lens 17 depending on which position it is. The convergence / divergence state of the laser beam is changed. The reason why the first collimating lens 14 can be moved in the optical axis direction is to enable correction of spherical aberration.

  The collimating lens driving unit 20 may have any configuration as long as it can move the first collimating lens 14 in the optical axis direction. For example, it can be configured as shown in FIG. FIG. 3 is a schematic perspective view showing the configuration of the collimating lens driving means 20 of the present embodiment. As shown in FIG. 3, the collimating lens driving unit 20 includes a base 201, a movable portion 202, two guide shafts 203 a and 203 b, a motor 204, a lead screw 205, and a lead nut 206.

  The base 201 carries various members constituting the collimating lens driving means 20 and is fixed to the slide base 2 (see FIG. 2) with screws 18. The movable portion 202 is formed with a holding portion that holds the collimating lens 14 and a holding portion that holds the lead nut 206. The movable portion 202 is also formed with two through holes so that the two guide shafts 203a and 203b can be penetrated. The guide shafts 203a and 203b are arranged so as to be parallel to the optical axis. The motor 204 is a stepping motor. The lead screw 205 is directly connected to the output shaft of the motor 204 and meshes with a lead nut 206 held by the holding portion of the movable portion 202.

  For this reason, the lead screw 205 rotates with the rotation of the motor 204, and the lead nut 206 is conveyed by the rotation of the lead screw 205. As the lead nut 206 is transported, the movable portion 202 also moves along the guide shafts 203a and 204. Thereby, the position of the first collimating lens 14 in the optical axis direction can be adjusted.

  The laser light emitted from the first collimating lens 14 passes through a quarter-wave plate 15 that functions as an optical isolator in cooperation with the polarization beam splitter 13, is reflected by the first rising mirror 16, and changes its direction to light. The incident light enters the first objective lens 17 in a direction perpendicular to the information recording surface of the recording medium. The first objective lens 17 condenses the incident laser light on the information recording surface of the optical recording medium.

  The laser beam reflected by the optical recording medium is transmitted through the first objective lens 17, reflected by the first rising mirror 16, transmitted through the quarter wavelength plate 15 and the first collimating lens 14 in this order, and then further polarized. The splitter 13 is also transmitted. The laser beam that has passed through the polarization beam splitter 13 passes through the first cylindrical lens 18 having a function of providing astigmatism, and is condensed on the light receiving surface of the first photodetector 19.

  Next, an optical system for DVD / CD will be described. The optical system for DVD / CD guides the laser light emitted from the second laser diode 21 to the optical recording medium and guides the reflected light reflected by the optical recording medium to the second photodetector 27. The DVD / CD optical system includes a half mirror 22, a second collimating lens 23, a second raising mirror 24, a second objective lens 25, and a second cylindrical lens 26.

  The second laser diode 21 is a light source capable of switching and emitting laser light having a wavelength of 650 nm and laser light having a wavelength of 780 nm. Such a light source is realized by, for example, a so-called monolithic laser diode or a hybrid laser diode. The second photodetector 27 is a light receiving unit that converts an incident optical signal into an electrical signal and outputs the electrical signal. The electric signal output from the second photodetector 27 is processed by a signal processing unit (not shown) to become a reproduction signal, a focus error signal, a tracking error signal, and the like.

  The laser light emitted from the second laser diode 21 is reflected by the half mirror 22, sent to the second collimating lens 23, and converted into parallel light. The laser beam (parallel light) emitted from the second collimating lens 23 is reflected by the second raising mirror 24, and the direction thereof is set to a direction orthogonal to the information recording surface of the optical recording medium. 25 is incident. The second objective lens 25 condenses the incident laser light on the information recording surface of the optical recording medium.

  The laser light reflected by the optical recording medium passes through the second objective lens 25, then is reflected by the second raising mirror 24, and passes through the second collimating lens 23 and the half mirror 22 in this order, thereby providing astigmatism. The light passes through the second cylindrical lens 26 having a function and is condensed on the light receiving surface of the second photodetector 27.

  Note that the configuration of the optical system of the optical pickup device 1 shown here is merely an example, and various changes can naturally be made without departing from the object of the present invention.

  By the way, the first objective lens 17 and the second objective lens 25 described above are mounted on the objective lens actuator 30. Thus, the first objective lens 17 and the second objective lens 25 can move in the focus direction and the tracking direction. For this reason, in the optical pickup device 1, focus control and tracking control are possible.

  The focus direction is a direction in which the objective lenses 17 and 25 are in contact with and away from the optical recording medium, and the tracking direction is a direction parallel to the radial direction of the disk-shaped optical recording medium. The focus adjustment is an adjustment performed so that the focal position of the first objective lens 8 or the second objective lens 15 always matches the information recording surface of the optical recording medium. The tracking adjustment is formed on the information recording surface. This adjustment is performed so that the position of the beam spot always follows the track formed on the optical recording medium.

  The configuration of the objective lens actuator 30 is not particularly limited as long as the first objective lens 17 and the second objective lens 25 can be moved in the focus direction and the tracking direction. In the present embodiment, the objective lens actuator 30 is configured as shown in FIG. FIG. 4 is a schematic perspective view showing the configuration of the objective lens actuator 30 of the present embodiment.

  In FIG. 4, a base 31 for an objective lens actuator (hereinafter referred to as an act base) is made of a metal having ferromagnetism. The act base 31 is formed with a through hole (not shown) through which the laser beam passes substantially at the center. And the lens holder 32 mentioned later for details is arrange | positioned on this through-hole. On the act base 21, a pair of permanent magnets 33a and 33b are provided so as to be opposed to each other with a predetermined interval so as to sandwich the lens holder 32 therebetween.

  The permanent magnets 33a and 33b are arranged so that the same pole (N pole or S pole) faces each other. In addition, yokes 31a and 31b bent from the act base 31 are magnetized on the outer surfaces of the permanent magnets 33a and 33b.

  The lens holder 32 includes a holding unit that holds the first objective lens 17 and a holding unit that holds the second objective lens 25, and holds the two objective lenses 17 and 25 side by side. ing. The first objective lens 17 and the second objective lens 25 held by these holding units are mounted on the lens holder 32 so that the coma aberration directions of the first objective lens 17 and the second objective lens 25 are aligned. The reason for aligning the coma aberration directions of the two objective lenses 17 and 25 will be described later.

  The lens holder 32 has through holes (not shown) so that the laser beams emitted from the first laser diode 11 and the second laser diode 21 can enter the first objective lens 17 and the second objective lens 25, respectively. Has been.

  A focus coil (not shown) is wound inside the side wall of the lens holder 32 along the side wall, and is fixed with an adhesive or the like. A pair of tracking coils 34a and 34b are formed on the outside of the side wall of the lens holder 32 facing the permanent magnet 33a, and a pair of tracking coils 34a and 34b are formed on the outside of the side wall facing the permanent magnet 33ba. A pair of tracking coils 34c and 34d are fixed with an adhesive or the like. Further, the tracking coil 34a and the tracking coil 34c, and the tracking coil 34b and the tracking coil 34d are respectively arranged at symmetrical positions. The four tracking coils 34a to 34d are connected by a single line as a whole.

  On the act base 31, a gel box 36 is fixed which is in contact with the outer surface side of the yoke 31 b magnetically attached to the permanent magnet 33 b and is formed in a substantially U shape in plan view. The Further, on the act base 31, a circuit board 37 disposed adjacent to the outer surface of the gel box 36 is erected.

  One end of each conductive wire 35 is connected to the circuit board 37 by soldering at two locations in the vertical direction on both the left and right sides. Insertion holes 36 a and 36 b are formed in the gel box 36. Two wires 35 are inserted through each of the insertion holes 36a and 36b. Each insertion hole 36a, 36b is filled with a gel material mainly composed of silicon. By this gel material, vibration generated in each wire 35 in response to driving of the lens holder 32 is attenuated.

  The other end of the wire 35 is fixed to a wire fixing portion 38 provided on the side wall of the lens holder 32 by soldering. Accordingly, the lens holder 32 is supported by the four wires 35 so as to be swingable with respect to the act base 31. Of the wires 35 fixed to the wire fixing portion 38, the upper two wires are in a state of being electrically connected to the focus coil. The lower two wires 35 are electrically connected to the tracking coils 34a to 34d.

  When focus adjustment and tracking adjustment are performed using the objective lens actuator 30 configured as described above, current is supplied from the circuit board 37 to the focus coil and the tracking coil through the wire 35. The lens holder 32 is displaced in the focus direction and the tracking direction by an electromagnetic action with a magnetic field formed by the permanent magnets 33a and 33b. By adjusting the magnitude and direction of the current supplied to the coils (focus coil, tracking coil), the displacement of the lens holder 32 in the focus direction and the tracking direction is adjusted.

  Referring to FIG. 2, in optical pickup device 1, first laser diode 11, an optical member excluding first objective lens 17 among optical elements constituting an optical system for BD, first photo detector 19, and second photo detector. 27 are mounted on the slide base 2 individually (separately without being united). On the other hand, the optical members excluding the second objective lens 25 among the optical elements constituting the second laser diode 21 and the DVD / CD optical system are mounted on a holder 28 formed of, for example, a resin, and the slide base 2 is mounted. It is mounted on.

  FIG. 5 is a schematic perspective view showing the holder 28 provided in the optical pickup device 1 of the present embodiment and members mounted thereon. The holder 28 is formed in a substantially box shape so that the half mirror 22, the second collimating lens 23, the second raising mirror 24, and the second cylindrical lens 26 can be held therein. A holding part is formed. The second laser diode 21 is fixed to a predetermined outer wall of the holder 28 by, for example, screwing.

  The holder 28 has a through hole (not shown) so that the laser light emitted from the second laser diode 21 can reach the half mirror 22. In addition, a through hole (not shown) is formed in the holder 28 so that the laser light reflected by the optical recording medium and passing through the second cylindrical lens 26 can reach the second photodetector 27. In this embodiment, the holder 28 formed in this way is bonded and fixed after adjusting its position while moving with respect to the slide base 2. That is, in the optical pickup device 1 of the present embodiment, among the optical members that constitute the DVD / CD optical system, the optical member that is not mounted on the objective lens actuator 30 is unitized with the second laser diode 21 and slides. It is to be mounted on the base 2.

  The optical pickup device 1 according to the present embodiment is configured as described above. With this configuration, the wavefront aberration can be easily and appropriately adjusted when the optical pickup device 1 is manufactured. . Hereinafter, an example of a method for adjusting the wavefront aberration during manufacturing in the optical pickup device 1 of the present embodiment will be described.

  When the optical pickup device 1 is manufactured, first, the optical member excluding the first objective lens 17 among the optical members constituting the first laser diode 11 and the optical system for BD is mounted on the slide base 2. At this time, a laser beam is emitted from the first laser diode 11 and the mounting position of each member is adjusted while observing the laser beam reflected by the first rising mirror 16 with, for example, an interferometer or the like. Adjustments for coma and astigmatism are made, and then each member is fixed.

  In addition, the optical member excluding the second objective lens 25 among the optical members constituting the second laser diode 21 and the optical system for DVD / CD is mounted on the holder 28. At this time, the laser beam is emitted from the second laser diode 21 and the attachment position of each member is adjusted while observing the laser beam reflected by the second raising mirror 24 with, for example, an interferometer, etc. Adjustments for coma and astigmatism are made, and then each member is fixed.

  When the above adjustment is completed, the objective lens actuator 30 is then mounted on the slide base 2. The first objective lens 17 held in the lens holder 32 of the objective lens actuator 30 is determined in its orientation and held in the lens holder 32 so that astigmatism generated in the BD optical system can be suppressed. Is done. The direction of astigmatism of the first objective lens 17 is known in advance, and the orientation of the first objective lens 17 is determined so as to suppress astigmatism in relation to astigmatism during the previous adjustment. . The direction of astigmatism of the first objective lens 17 is, for example, irradiating laser light from the reference light source toward the first objective lens 17 and observing the laser light emitted from the first objective lens 17 with an interferometer. By doing so, it can be obtained in advance.

  Further, the second objective lens 25 held by the lens holder 32 of the objective lens actuator 30 has a coma aberration direction that is the same as the coma aberration direction of the first objective lens 17. Retained. The coma aberration direction of each of the first objective lens 17 and the second objective lens 25 is, for example, laser light emitted from the reference light source toward the objective lenses 17 and 25 and emitted from the objective lenses 17 and 25. Can be obtained by observing with an interferometer.

  When the objective lens actuator 30 is mounted on the slide base 2, laser light is emitted from the first laser diode 11. Then, while observing the laser light emitted from the first objective lens 17 with an interferometer, the inclination of the objective lens actuator 30 is adjusted so that the coma aberration is suppressed as much as possible. Thereby, the coma generated in the optical system for BD can be adjusted to the best state.

  Thereafter, the unit that is unitized by being mounted on the holder 28 is mounted on the slide base 2. At this time, the slide base 2 of the holder 28 is configured so that the astigmatism is suppressed while the laser light is emitted from the second laser diode 21 and the laser light emitted from the second objective lens 25 is observed with, for example, an interferometer. Make adjustments to the installation status. In the adjustment, for example, the holder 28 is held by a jig, and the adjustment is performed by moving the holder 28 together with the jig. Note that an adjustment unit may be formed on the slide base 2 and the mounting state of the holder 28 may be adjusted by the adjustment unit.

  The objective lens actuator 30 adjusted to suppress coma and the holder 28 adjusted to suppress astigmatism are finally bonded and fixed. For the adhesive fixation, for example, an adhesive that is cured by UV irradiation is used.

  When the wavefront aberration is adjusted as described above when the optical pickup device 1 is manufactured, coma and astigmatism are appropriately generated not only for the BD optical system but also for the DVD / CD optical system. Can be suppressed. That is, the second objective lens 25 is arranged so that the coma aberration direction is the same as that of the first objective lens 17 when held by the lens holder 32. Therefore, the coma aberration of the laser light emitted from the second objective lens 25 is suppressed by tilting the objective lens actuator 30 so as to suppress the coma aberration of the laser light emitted from the first objective lens 17. Is possible.

  The coma aberration of the laser light emitted from the first objective lens 17 and the coma aberration of the laser light emitted from the second objective lens 25 may have different absolute values. For this reason, in the method of the present embodiment, there is a case where the best state of suppression of coma aberration of the laser light emitted from the second objective lens 25 may not be achieved, but at a level that does not cause a problem when reading or writing information. It is possible to suppress coma.

  Further, astigmatism generated in the DVD / CD optical system can be suppressed by adjusting the arrangement of the holder 28 that unitizes the second laser diode 21 and a part of the DVD / CD optical system. . And since the holder 28 is large in size, adjustment work is easy to perform.

  That is, since the optical pickup device 1 of the present embodiment adjusts the wavefront aberration using the light source actually mounted on the optical pickup device 1 without using the reference light source, the wavefront aberration is appropriately adjusted. Is possible. Further, there is no step of adjusting the tilt of the objective lens mounted on the lens holder 32 of the objective lens actuator 30, and the adjustment of the wavefront aberration is easy because the unitized holder 28 is adjusted.

  The embodiment described above is an example, and the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the object of the present invention.

  In this embodiment, a part of the DVD / CD optical system is mounted on the holder 28 to form a unit. However, the present invention is not limited to this. That is, contrary to the configuration of the present embodiment, a part of the BD optical system is unitized and mounted on the slide base 2, and the DVD / CD optical system is individually arranged on the slide base 2. It does not matter as a configuration.

  In the present embodiment, the second photodetector 27 is not mounted on the holder 28. However, the second photodetector 27 may be mounted on the holder 28.

  In the present embodiment, the optical pickup device 1 is configured to have two optical systems, that is, a BD optical system and a DVD / CD optical system. However, the present invention is not limited to this configuration. . That is, the type of the optical recording medium that is read or written by the optical pickup device may naturally be different from the configuration of the present embodiment. Furthermore, the present invention is also applicable when there are three or more optical systems that guide light emitted from the light source to the recording surface of the optical recording medium.

  According to the present invention, in an optical pickup device having a plurality of optical systems that are selectively used depending on the type of optical recording medium, it is possible to realize a structure capable of easily and appropriately adjusting wavefront aberrations during manufacturing. For this reason, the present invention is useful.

These are the schematic plan views at the time of seeing the optical pick-up apparatus of this embodiment from the upper side. FIG. 2 is a schematic plan view of the optical pickup device of this embodiment as viewed from below. These are the schematic perspective views which show the structure of the collimating lens drive means of this embodiment. These are the schematic perspective views which show the structure of the objective-lens actuator of this embodiment. These are the schematic perspective views which showed the holder with which the optical pick-up apparatus of this embodiment is equipped, and the member mounted in it.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical pick-up apparatus 2 Slide base 11 1st laser diode (light source)
16 First raising mirror 17 First objective lens 21 Second laser diode (light source)
24 Second Raising Mirror 25 Second Objective Lens 28 Holder 30 Objective Lens Actuator 32 Lens Holder

Claims (4)

An optical pickup device having a plurality of optical systems that guide light emitted from a light source to an optical recording medium and guide light reflected by the optical recording medium to a light receiving unit,
An objective lens that is included in each of the plurality of optical systems, and focuses light emitted from the light source onto an information recording surface of the optical recording medium;
A base on which the plurality of optical systems are mounted;
An actuator mounted on the base and holding a plurality of objective lenses, and an actuator that allows the objective lens to move by moving the lens holder;
In each optical system except one of the plurality of optical systems, an optical member that is not mounted on the actuator among optical members that constitute the optical system is unitized with the light source and mounted on the base.
The plurality of objective lenses are mounted on the lens holder with their coma aberration directions aligned in the same direction. The optical system includes a mirror that reflects light emitted from the light source and directs the light in a direction orthogonal to the information recording surface,
The optical member unitized with the light source in the optical system includes the mirror, an optical member disposed while light emitted from the light source reaches the mirror, and light reflected by the optical recording medium. The optical pickup device according to claim 1, wherein the optical pickup device is an optical member disposed between the mirror and the light receiving unit.   The optical pickup device according to claim 1, wherein the number of the optical systems is two.   Of the two optical systems, one is an optical system used for an optical recording medium according to the BD standard, and the other is an optical system used for an optical recording medium according to the CD standard and the DVD standard. The optical pickup device according to claim 3.

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