JP2009252327A - Optical pickup apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup apparatus which prevents vibration during sliding by reducing the number of components. <P>SOLUTION: The optical pickup apparatus 1 includes a base 2 which is provided slidably along guide shafts 31a and 31b and to which a light source (not shown in the figure) is mounted, and an actuator 3 which is disposed on the base 2 and drives objective lenses 17 and 25 focusing light from the light source on the information recording surface of an optical recording medium. Mounted to the base 2 is a sheet metal member 4 obtained by integrally forming a cover part for covering the actuator 3 and an elastic part which presses the guide shaft 31b to a part of the base 2 with elastic force. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical pickup device used for reading information recorded on an optical recording medium and writing information on the optical recording medium.

  Optical disks (optical recording media) such as compact disks (hereinafter referred to as CDs) and digital versatile disks (hereinafter referred to as DVDs) have become widespread. Furthermore, recently, an optical disc capable of recording a large amount of information such as a Blu-ray disc (hereinafter referred to as BD) has been put into practical use. Such reading of information from the optical disk and writing of information to the optical disk are performed using an optical pickup device.

  6A and 6B are schematic plan views showing the configuration of a conventional optical pickup device. FIG. 6A is a view as seen from above, and FIG. 6B is a side view (from the O position in FIG. 6A). FIG. In FIG. 6A, guide shafts 105a and 105b are also shown for convenience of explanation, although they are not members constituting the optical pickup device. Hereinafter, the configuration of the conventional optical pickup device 1 will be described with reference to FIG.

  The optical pickup device 100 includes a slide base 101 and an objective lens actuator 102.

  The slide base 101 is provided with cylindrical bearing portions 101a and 101b at a predetermined interval at one end portion, and a substantially U-shaped bearing portion 101c is provided at the other end portion facing it. A first guide shaft (main shaft) 105a is inserted through the cylindrical bearing portions 101a and 101b. On the other hand, the second guide shaft (secondary shaft) 105b is inserted through the substantially U-shaped bearing portion 101c. Thereby, the slide base 101 is slidably held with respect to the two guide shafts 105a and 105b.

  The slide base 101 includes a light source composed of a semiconductor laser or the like, a light receiving element that receives reflected light emitted from the light source and reflected by the optical disc, and an optical path for the light emitted from the light source to an objective lens 103 described later. Various optical members (all of which are not shown) and the like that are arranged on the optical path where the reflected light reflected by the optical disk reaches the light receiving element are mounted.

  The objective lens actuator 102 focuses the objective lens 103 that collects the light emitted from the light source onto the information recording surface of the optical disc (arranged on the front side of the paper surface in FIG. 6A), for example, in the focus direction and the track. It is a device that can move in the direction. Here, the focus direction is a direction parallel to the direction perpendicular to the information recording surface of the optical disk, and the track direction is a direction parallel to the radial direction of the optical disk and the longitudinal direction of the above-described guide shafts 105a and 105b. Parallel to the direction. Then, by making the objective lens 103 movable in the focus direction or the track direction in this way, the focal position of the objective lens 103 is controlled (focusing control) so that it is always aligned with the information recording surface. The collected light spot is controlled (tracking control) so as to always follow the track of the optical disk.

  Specifically, the objective lens actuator 102 includes an act base 102a, a lens holder 102b that holds the objective lens 103, and a plurality of rod-like elastic support members that support the lens holder 102b so as to be swingable with respect to the act base 102a. 102c and two permanent magnets 102d which are arranged so as to sandwich the lens holder 102b and are erected on the act base 102a.

  Then, by passing an electric current through a focus coil and a track coil (not shown) attached to the lens holder 102b, the lens holder 102b swings due to electromagnetic force action. Thereby, the objective lens actuator 102 allows the objective lens 103 to move in the focus direction and the track direction. Although not shown for convenience of explanation, a part of the objective lens actuator 102 is covered with a cover made of a sheet metal member for the purpose of protecting the rod-like elastic support member 102c, for example. This sheet metal member is fixed to the act base 102a.

  The conventional optical pickup device 100 configured as described above is moved in the radial direction of the optical disk along the guide shafts 105a and 105b by a drive mechanism (not shown), and can access each address of the optical disk rotating at high speed.

Incidentally, in the conventional optical pickup device 100 configured as described above, it is common to provide a vibration preventing member so that the slide base 101 sliding on the guide shafts 105a and 105b does not vibrate (for example, a patent). See references 1 and 2). The vibration preventing member is made of an elastic member and is attached to the slide base 101 with screws or the like. The vibration preventing member is provided so as to push up the auxiliary shaft (second guide shaft 105b) from below by an elastic force. Thereby, a part of slide base 101 (upper part of bearing part 101c) and a countershaft 105b can be secured, and vibration of slide base 101 can be prevented.
Japanese Patent No. 3434673 JP 2000-182338 A

  However, such a mechanism for preventing the vibration of the slide base 101 is indispensable in the optical pickup apparatus 100, but in the conventional configuration, it is separately prepared as a vibration preventing member. For this reason, there are problems that the number of parts increases and the number of manufacturing steps of the optical pickup device 1 increases.

  In view of the above points, an object of the present invention is to provide an optical pickup device that can reduce the number of components and prevent vibration during sliding.

  In order to achieve the above object, the present invention provides a base that is slidable along a guide shaft, to which a light source is attached, and is disposed on the base, and transmits light from the light source to an information recording surface of an optical recording medium. And an actuator that drives an objective lens that focuses light on the base. The base includes a cover portion that covers the actuator, and an elastic portion that presses the guide shaft against a part of the base by an elastic force. And a sheet metal member formed integrally with each other is attached.

  According to this configuration, the protection of the actuator and the vibration prevention of the base are realized by attaching one sheet metal member to the base. That is, according to this configuration, only one member needs to be prepared for members that have been prepared separately as a protective cover and a vibration preventing member. Therefore, it is possible to provide an optical pickup device that can reduce the number of parts and prevent vibration during sliding.

  In the optical pickup device having the above configuration, the sheet metal member is formed to be fixed to the base by a fixing member, and the fixing portion fixed by the fixing member is further integrally formed on the sheet metal member. It is good as well. According to this configuration, since the sheet metal member is fixed by a fixing member such as a screw, the sheet metal member can be firmly fixed. Moreover, the fixing part is formed integrally with the cover part and the elastic part, and can suppress an increase in the number of parts.

  In the optical pickup device having the above configuration, it is preferable that the fixing portion is formed between the cover portion and the elastic portion. According to this structure, it can suppress that the vibration in an elastic part is transmitted to a cover part.

  As a specific configuration of the optical pickup device having the above configuration, the cover portion has a substantially box shape, and the elastic portion and the fixing portion are provided side by side so as to protrude from one side surface of the cover portion. It is good.

  ADVANTAGE OF THE INVENTION According to this invention, the optical pick-up apparatus which can reduce the number of parts and can prevent the vibration at the time of sliding can be provided.

  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 showing the configuration of the optical pickup device of the present embodiment. FIG. 2 is a schematic side view showing the configuration of the optical pickup device of the present embodiment, and is a side view seen from the position A side in FIG. In FIG. 1, for convenience of explanation, guide shafts 31a and 31b that are not members constituting the optical pickup device 1 are also shown.

  The optical pickup device 1 irradiates an optical disk (not shown) (arranged on the front side of the paper with reference to FIG. 1), receives reflected light reflected by the optical disk, and converts the optical signal into an electrical signal. And output. As shown in FIG. 1, the optical pickup device 1 is arranged in a movable state along two guide shafts 31a and 31b extending in a direction parallel to the radial direction of the optical disk. As a result, the optical pickup device 1 can access each address formed on the optical disk rotating at high speed, and can read information recorded on the optical disk and write information on the optical disk. Hereinafter, a detailed configuration of the optical pickup device 1 of the present embodiment will be described.

  As shown in FIG. 1, the optical pickup device 1 of this embodiment includes a slide base 2, an objective lens actuator 3, and a sheet metal member 4. As shown in FIGS. 1 and 2, the cylindrical base portions 2a and 2b are attached to the slide base 2 so that the slide base 2 is slidably attached to the two guide shafts 31a and 31b. A substantially U-shaped bearing portion 2c is provided. Specifically, the cylindrical bearing portions 2a and 2b are provided at one end of the slide base 2 at a predetermined interval, and the substantially U-shaped bearing portion 2c is formed by the cylindrical bearing portions 2a and 2b. It is provided in the vicinity of the other end facing the provided end.

  The slide base 2 is provided with the optical system shown in FIG. FIG. 3 is a schematic diagram showing a configuration of an optical system provided in the optical pickup device 1 of the present embodiment. Further, the two objective lenses 17 and 25 in FIG. 3 are arranged on the slide base 2 in a state where they are mounted on the objective lens actuator 3 arranged on the slide base 2 in detail.

  The optical pickup device 1 of the present embodiment is provided so as to be able to read and write information with respect to three types of optical disks of BD, DVD, and CD. As shown in FIG. 3, there are two types of optical systems: an optical system for BD and an optical system for DVD and CD (hereinafter sometimes referred to as DVD / CD). Hereinafter, the optical system for BD and the optical system for DVD / CD will be described separately with reference to FIG.

  First, an optical system for BD will be described. The BD optical system includes a first semiconductor laser 11, a diffraction element 12, a polarization beam splitter 13, a first collimating lens 14, a quarter wavelength plate 15, a first raising mirror 16, a first An objective lens 17, a first cylindrical lens 18, and a first photo detector 19 are provided. The first semiconductor laser 11 emits laser light having a wavelength of 405 nm, for example.

  Laser light (linearly polarized light) emitted from the first semiconductor laser 11 is divided into a main beam and two sub beams by the diffraction element 12. Thereafter, the light is reflected by the polarization beam splitter 13 and passes through the first collimating lens 14. The first collimating lens 14 is provided so as to be movable in the optical axis direction (the direction indicated by the arrow in FIG. 3) so that spherical aberration can be corrected. In addition, by adjusting the position of the first collimating lens 14, the convergence / divergence state of the light incident on the first objective lens 17 can be changed.

  The laser light that has passed through the first collimating lens 14 is converted into circularly polarized light by the quarter-wave plate 15, reflected by the first rising mirror 16, and its traveling direction toward the optical disk (in FIG. The direction toward the front corresponds to the above). The light reflected by the first raising mirror 16 is condensed on the recording layer of the optical disk by the first objective lens 17.

  Thereafter, the reflected light reflected by the recording layer passes through the first objective lens 17, is reflected by the first rising mirror 16, and is converted into linearly polarized light by the quarter wavelength plate 15. The polarization direction at this time is a direction rotated by 90 degrees with respect to the polarization direction of the linearly polarized light emitted from the first semiconductor laser 11.

  The reflected light that has passed through the quarter-wave plate 15 passes through the first collimating lens 14 and the first polarizing beam splitter 13, is given astigmatism by the first cylindrical lens 18, and is condensed on the first photodetector 19. . The first photodetector 19 converts the received optical signal into an electrical signal and outputs it. The output electric signal is processed into a reproduction RF signal, a focus error signal, a tracking error signal, and the like.

  Next, an optical system for DVD / CD will be described. The optical system for DVD / CD includes a second semiconductor laser 21, a half mirror 22, a second collimating lens 23, a second rising mirror 24, a second objective lens 25, a second cylindrical lens 26, A second photo detector 27. For example, the second semiconductor laser 21 switches and emits a laser beam having a wavelength of 650 nm and a laser beam having a wavelength of 780 nm. As such a two-wavelength laser, a so-called monolithic semiconductor laser or a hybrid semiconductor laser is preferably used.

  Laser light (linearly polarized light) emitted from the second semiconductor laser 21 is reflected by the half mirror 22 and converted into parallel light by the second collimating lens 23. The light converted into parallel light by the second collimating lens 23 is reflected by the second raising mirror 24, and its traveling direction is toward the optical disk (in FIG. 3, the direction toward the front with respect to the paper surface corresponds to this). ). The light reflected by the second raising mirror 24 is condensed on the recording layer of the optical disc by the second objective lens 25.

  Thereafter, the reflected light reflected by the recording layer passes through the second objective lens 25, is reflected by the second rising mirror 24, passes through the second collimator lens 23 and the half mirror 22, and is reflected by the second cylindrical lens 26. Astigmatism is given and the light is condensed on the second photodetector 27. The second photodetector 27 converts the received optical signal into an electrical signal and outputs it. The output electric signal is processed into a reproduction RF signal, a focus error signal, a tracking error signal, and the like.

  Returning to FIG. 1 or FIG. 2, the objective lens actuator 3 arranged on the slide base 2 is equipped with the first objective lens 17 and the second objective lens 25, and these objective lenses are focused in the focus direction (see FIG. 2). And movably in the track direction (see FIG. 1). Thereby, focusing control and tracking control in the optical pickup device 1 are possible. The configuration of the objective lens actuator 3 is the same as the configuration of the objective lens actuator 102 shown in FIG. 6 except that the lens holder holds the two objective lenses 17 and 25. Therefore, the detailed configuration of the objective lens actuator 3 is described here. Description is omitted.

  The sheet metal member 4 firstly protects the objective lens actuator 3 and secondly prevents vibrations that occur when the slide base 2 is slid along the guide shafts 31a and 31b. , Attached to the slide base 2.

  Specifically, the objective lens actuator 3 provided in the optical pickup device 1 has a configuration in which a lens holder that holds the objective lenses 17 and 25 is swingably supported by a rod-like elastic support member (not shown). . In such a configuration, it is necessary to be careful not to touch the rod-like elastic support member. Further, the bearing portion 2c through which the guide shaft 31b serving as the auxiliary shaft of the slide base 2 is inserted is formed in consideration of the dimensional tolerance of parts. For this reason, when the slide base 2 is attached to the guide shafts 31a and 31b and the slide base 2 is slid, vibration (rattle) may occur. The sheet metal member 4 eliminates these problems.

  Hereinafter, the details of the sheet metal member 4 will be described with reference to FIG. FIG. 4 is a schematic perspective view showing the configuration of the sheet metal member 4 provided in the optical pickup device 1 of the present embodiment. As shown in FIG. 4, the sheet metal member 4 is formed by integrally forming a cover portion 41, a fixing portion 42, and an elastic portion 43. For the sheet metal member 4 of the present embodiment, a sheet metal material having a thickness of, for example, about 0.3 mm is used. Moreover, as a material of the sheet metal member 4 of the present embodiment, for example, stainless steel (SUS) is selected, and among them, those having particularly high elasticity are preferably used.

  The cover portion 41 is a portion that is bent into a substantially box shape, and this portion is formed so as to protect the objective lens actuator 3 by covering the objective lens actuator 3. However, the upper surface 41a of the cover portion 41 is provided with a window portion 44 formed by cutting out part of the objective lens 17 and 25 mounted on the objective lens actuator 3 so as not to be covered. .

  The fixed portion 42 and the elastic portion 43 are formed by bending one side surface 41b of the cover portion 41 having a substantially box shape, and are provided side by side in a state protruding from the one side surface 41b. The fixing portion 42 is formed with a notch portion 42a having a substantially tongue shape in plan view so that the sheet metal member 4 can be fixed to the slide base 2 with screws 5 (see FIGS. 1 and 2).

  The elastic part 43 has a bent part 43a that is partially folded back toward the upper side, and has a substantially fishhook shape in side view. The elastic part 43 has elasticity by forming the bent part 43a. FIG. 5 is an explanatory diagram for explaining the function of the elastic portion 43 of the sheet metal member 4. As shown in FIG. 5, the guide shaft 31 b inserted into the bearing portion 2 c formed in a substantially U shape is pressed upward (indicated by an arrow in FIG. 5) by the bent portion 43 a of the elastic portion 43, and the bearing It is pressed against the upper surface of the part 2c. For this reason, even if the slide base 2 slides along the guide shafts 31a and 31b, vibration (rattle) does not occur.

  As described above, the sheet metal member 4 of the present embodiment has the role of protecting the objective lens actuator 3 and the role of preventing vibration when the slide base 2 slides along the guide shafts 31a and 31b. It has a configuration that can be demonstrated with one member. Therefore, the number of parts can be reduced as compared with the conventional configuration in which the members exhibiting the respective functions are separately prepared and assembled. Therefore, workability at the time of manufacturing the optical pickup device can be reduced and workability can be improved.

  Further, in the present embodiment, the sheet metal member 4 is configured to be fixed by screws 5 at a fixing portion 42 formed between the cover portion 41 and the elastic portion 43. Such a configuration is preferable because vibration in the elastic portion 43 is difficult to be transmitted to the cover portion 41. The sheet metal member 4 is preferably fixed to the slide base 2 by using not only the screw 5 but also an engagement portion that engages with the sheet metal member 4 on the slide base 2 and fixing the sheet metal member 4 using the engagement portion. .

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

  For example, in the present embodiment, the sheet metal member 4 is configured by integrally forming the cover portion 41, the fixing portion 42, and the elastic portion 43. However, the present invention is not limited to this configuration, and a configuration without the fixing portion 42 may be employed. In the case of such a configuration, for example, a mechanism for holding the sheet metal member 4 on the slide base 2 may be provided. Even when the fixing portion is formed on the sheet metal member, the fixing portion may not be provided between the cover portion and the elastic portion. However, as described above, it is preferable to form the fixing portion 42 between the cover portion 41 and the elastic portion 43 as in the present embodiment in consideration of prevention of vibration of the cover portion and the like.

  In the present embodiment, the case where the present invention is applied to an optical pickup device corresponding to BD, DVD, and CD has been described. However, it goes without saying that the present invention can also be applied to an optical pickup device corresponding to a single optical disc, or an optical pickup device corresponding to an optical disc corresponding to a plurality of types of optical discs but different from the present embodiment.

  The optical pickup device of the present invention realizes prevention of vibration when the optical pickup device slides by reducing the number of parts, and can be widely applied in the field of optical pickup devices.

These are the schematic plan views which show the structure of the optical pick-up apparatus of this embodiment. These are the schematic side views which show the structure of the optical pick-up apparatus of this embodiment, and are the side views seen from the position A side of FIG. These are the schematic diagrams which show the structure of the optical system with which the optical pick-up apparatus of this embodiment is provided. These are the schematic perspective views which show the structure of the sheet-metal member with which the optical pick-up apparatus of this embodiment is provided. These are explanatory drawings for demonstrating the function of the elastic part of the sheet-metal member with which the optical pick-up apparatus of this embodiment is provided. These are the schematic plan views which show the structure of the conventional optical pick-up apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical pick-up apparatus 2 Slide base 3 Objective lens actuator 4 Sheet metal member 5 Screw (fixing member)
11 First semiconductor laser (light source)
21 Second semiconductor laser (light source)
17 First objective lens 25 Second objective lens 31a First guide shaft (guide shaft)
31b Second guide shaft (guide shaft)
41 Cover part 42 Fixing part 43 Elastic part

Claims (4)

A base that is slidable along the guide axis and to which a light source is attached;
An actuator that is disposed on the base and drives an objective lens that focuses light from the light source on an information recording surface of an optical recording medium; and
In an optical pickup device comprising:
The base is attached with a sheet metal member integrally formed with a cover portion that covers the actuator and an elastic portion that presses the guide shaft against a part of the base by an elastic force. Pickup device. The sheet metal member is formed to be fixed to the base with a fixing member,
The optical pickup device according to claim 1, wherein a fixing portion fixed by the fixing member is further integrally formed on the sheet metal member.   The optical pickup device according to claim 2, wherein the fixing portion is formed between the cover portion and the elastic portion. The cover portion has a substantially box shape,
The optical pickup device according to claim 3, wherein the elastic portion and the fixing portion are provided side by side so as to protrude from one side surface of the cover portion.

Images