JP4400606B2 - Lens holder, objective lens driving device, optical head, and optical recording / reproducing device - Google Patents

Description

  The present invention relates to a lens holder on which an objective lens constituting an optical head for recording or reproducing data on an optical recording medium such as an optical disk is mounted, and the lens holder on which the objective lens is mounted is driven in a focus direction, a tracking direction, or the like. The present invention relates to an objective lens driving device, an optical head including the objective lens driving device, and an optical recording / reproducing apparatus including the optical head.

  Some conventional lens holders are made of a resin molded product including a lens support portion having a lens mounting surface and a bearing portion having a bearing surface provided vertically on the lens mounting surface. In this lens holder, the resin molded product is formed by injecting resin from a gate provided at the end of the bearing portion on the opposite side of the lens support portion (see, for example, Patent Document 1). . Hereinafter, this technique is referred to as a first conventional example.

  In addition, the conventional objective lens driving device is made of a resin molded product, and is formed between a cylindrical barrel portion, a cylindrical bearing portion disposed inside the barrel portion, and the barrel portion and the bearing portion. Some of them have a lens holder provided with a horizontal reinforcing plate and a vertical reinforcing plate connected to the outer peripheral surface of the bearing portion. The lens holder is movable in a direction along a fixed-side support shaft inserted into the bearing portion and in a rotation direction around the support shaft. Moreover, the constriction part is formed in the said reinforcement board in the connection part with respect to the outer peripheral surface of a bearing part. As the mold for injection molding of this lens holder, the one having an open gate is used for each cavity part for molding a vertical reinforcing plate having no constricted portion among the vertical reinforcing plates (for example, , See Patent Document 2). Hereinafter, this technique is referred to as a second conventional example.

Japanese Patent Laying-Open No. 2003-6895 (Claims 1, [0013] to [0018], FIGS. 1 and 2) Japanese Patent Laid-Open No. 10-289454 (Claims 1, [0011] to [0021], FIGS. 1 and 3)

  For example, when an optical recording / reproducing apparatus equipped with an optical head is mounted on an automobile and the automobile is left under a hot summer sun, the temperature in the vicinity of the dashboard where the optical recording / reproducing apparatus is installed is about 70 to 80 ° C. Rise up to. Even in such an extreme situation, the heat generated by the laser diode and various drive circuits tends to be trapped inside the optical recording / reproducing apparatus, and the temperature of each component often reaches around 50 ° C. Therefore, an optical head manufacturer performs an operation test for operating the completed optical head and objective lens driving device in a high temperature (for example, 55 ° C.) environment.

  In recent optical recording / reproducing apparatuses, there is a demand for downsizing, thinning, and weight reduction of the entire apparatus, and along with this, downsizing, thinning, and weight reduction of objective lenses, lens holders, and other parts are required. Progressing. For example, as in the first and second conventional examples described above, the lens holder is made of a resin molded product. In the case of the so-called ultra slim type optical recording / reproducing apparatus, the total thickness of the apparatus is about 9.5 mm, and the total thickness of the optical head is about 4.5 mm.

  As described above, when the above-described operation test is performed on the objective lens driving device including the lens holder that is formed of a resin molded product and is reduced in size, thickness, and weight, the objective lens is in the radial direction (the radius of the optical recording medium). There was a problem of tilting in the direction). As described above, when the objective lens is tilted, the light beam emitted from the laser diode is not correctly applied to the optical recording medium, and there is a possibility that data cannot be recorded or reproduced on the optical recording medium.

  Each of the first and second conventional examples described above relates to a lens holder made of a resin molded product, but solves a problem that occurs during molding. Therefore, the first and second conventional examples described above do not solve the problem caused by the change in the ambient temperature during mounting as described above. The problem to be solved by the present invention does not occur at the stage of the size of the lens holder and the objective lens driving device according to the first and second conventional examples.

  Furthermore, recently, for example, in a DVD (Digital Versatile Disk) player or the like, a laser diode such as a blue laser diode that irradiates a blue light beam having a short wavelength has come to be used. When the wavelength of the light beam to be handled in this way is short, there is a small allowable amount with respect to the mounting accuracy of each component, and thus the influence of the above-described disadvantage is enormous.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a lens holder, an objective lens driving device, an optical head, and an optical recording / reproducing device that can solve the above-described problems. .

In order to solve the above-described problem, a lens holder according to the first aspect of the present invention relates to a lens holder in which an objective lens is mounted at a central portion and elastically supported by a fixed portion so as to be relatively displaceable. A mold having a plurality of gates provided at symmetrical positions via a lens mounting portion on which the objective lens is mounted is integrally molded by injecting resin from the plurality of gates , so that the thinnest portion of the meat is formed. the thickness is not more 0.25mm or more, the thickest thickness of the portion Ri is Do the following resin molding 1.0 mm, the resin molded article corresponding to each of said plurality of gate provided in the mold The plurality of gate traces are formed in the vicinity of the lens mounting portion, and are formed in the vicinity of an objective lens protection member mounting portion for protecting the objective lens .

According to a second aspect of the present invention, an objective lens driving apparatus includes the lens holder according to the first aspect.
An optical head according to a third aspect of the invention is characterized by including the objective lens driving device according to the second aspect.
According to a fourth aspect of the present invention, an optical recording / reproducing apparatus includes the optical head according to the third aspect.

  According to the present invention, a lens holder according to the first aspect of the present invention relates to a lens holder in which an objective lens is mounted at a central portion and is elastically supported by a fixed portion so as to be relatively displaceable. It is made of a resin molded product that is integrally molded by injecting resin from the plurality of gates into a mold provided with a plurality of gates at symmetrical positions via a lens mounting portion on which is mounted. Therefore, even when the lens holder becomes hot, the objective lens mounted on the lens mounting portion hardly tilts in the radial direction, that is, the posture of the objective lens can be kept constant. Thereby, the reliability of the optical head having the objective lens driving device using the lens holder is improved. Therefore, since the light beam emitted from the laser diode constituting this optical head is correctly irradiated to the optical recording medium set in the optical recording / reproducing apparatus equipped with this optical head, data recording or recording on the optical recording medium is possible. Reproduction can be performed appropriately. As a result, the present invention is sufficiently applicable to an optical recording / reproducing apparatus that has been reduced in size, thickness, and weight to an ultra slim type or a lower type, or an optical recording / reproducing apparatus using a laser diode having a short light beam wavelength. Can be applied.

According to the present invention, an objective lens driving device according to a second aspect of the invention includes the lens holder according to the first aspect . Therefore, in an optical recording / reproducing apparatus equipped with an optical head using this objective lens driving device, the objective lens mounted on the lens mounting portion hardly tilts in the radial direction even when the lens holder becomes hot, that is, The posture of the objective lens can be kept constant. Thereby, the reliability of the optical head using this objective lens driving device is improved. Therefore, since the light beam emitted from the laser diode constituting this optical head is correctly irradiated to the optical recording medium set in the optical recording / reproducing apparatus equipped with this optical head, data recording or recording on the optical recording medium is possible. Reproduction can be performed appropriately. As a result, the present invention is sufficiently applicable to an optical recording / reproducing apparatus that has been reduced in size, thickness, and weight to an ultra slim type or a lower type, or an optical recording / reproducing apparatus using a laser diode having a short light beam wavelength. Can be applied.

According to the present invention, an optical head according to a third aspect of the invention includes the objective lens driving device according to the second aspect . Therefore, in the optical recording / reproducing apparatus equipped with this optical head, even when the lens holder becomes high temperature, the objective lens mounted on the lens mounting portion hardly tilts in the radial direction, that is, the posture of the objective lens is kept constant. Can be held. Thereby, the reliability of the optical head is improved. Therefore, since the light beam emitted from the laser diode constituting this optical head is correctly irradiated to the optical recording medium set in the optical recording / reproducing apparatus equipped with this optical head, data recording or recording on the optical recording medium is possible. Reproduction can be performed appropriately. As a result, the present invention is sufficiently applicable to an optical recording / reproducing apparatus that has been reduced in size, thickness, and weight to an ultra slim type or a lower type, or an optical recording / reproducing apparatus using a laser diode having a short light beam wavelength. Can be applied.

According to the present invention, an optical recording / reproducing apparatus according to a fourth aspect of the invention includes the optical head according to the third aspect . Therefore, in this optical recording / reproducing apparatus, even when the lens holder of the objective lens driving device constituting the optical head becomes high temperature, the objective lens mounted on the lens mounting portion hardly tilts in the radial direction, that is, the objective lens Can be held constant. As a result, the reliability of the optical head and thus the optical recording / reproducing apparatus is improved. Therefore, since the light beam emitted from the laser diode constituting the optical head is correctly applied to the optical recording medium set in the optical recording / reproducing apparatus, data recording or reproduction on the optical recording medium is performed appropriately. Can do. As a result, the present invention is sufficiently applicable to an optical recording / reproducing apparatus that has been reduced in size, thickness, and weight to an ultra slim type or a lower type, or an optical recording / reproducing apparatus using a laser diode having a short light beam wavelength. Can be applied.

Embodiment 1 FIG.
FIG. 1 is a schematic perspective view showing a configuration of a lens holder 1 according to Embodiment 1 of the present invention, and FIG. 2 is a schematic perspective view of the configuration of the lens holder 1 shown in FIG. The lens holder 1 is a resin molded product integrally formed by injection molding or extrusion molding using a lightweight and highly rigid synthetic resin as a raw material. Examples of the synthetic resin include liquid crystal polymer (LCP) and polyphenylene sulfide (PPS). As the lens holder 1 of this example, a synthetic resin whose glass resin or carbon is used to enhance the rigidity may be used.

  As shown in FIG. 4, the lens holder 1 has the objective lens 2 mounted at the center of the lens holder 1 and cantilevered on a fixed portion such as a wire base 7 via a suspension wire 6. It is a “lens center type” that is elastically supported so as to be relatively displaceable.

  The lens holder 1 has a rectangular parallelepiped shape as a whole, and the center of the lower surface portion and the center of the front surface portion are opened. The lens holder 1 includes a lens mounting area 11, coil attachment areas 12 and 13, and wire attachment areas 15 and 16. The lens mounting area 11 includes a lens mounting portion 21 for positioning the objective lens 2 (see FIG. 4) in the optical axis direction, and an adhesive 31 for fixing the objective lens 2 to the lens holder 1 (see FIG. 4). Adhesive application portions 22 to 25 to which the objective lens 2 is applied, an aperture 26 that narrows the incident light beam to an effective diameter of the objective lens 2, and an objective lens protection member (for protecting the objective lens 2) And an objective lens protection member mounting portion 27 and 28 to which a not shown) is mounted.

  Of the four adhesive application portions 22 to 25, in the vicinity of the adhesive application portions 22 and 23 located in the vicinity of the front surface of the lens holder 1, the positions are symmetrical, and the adhesive application portion Gate traces 29 and 30 are shown at approximately the same height as 22 and 23, respectively. That is, as a mold for molding the lens holder 1, two gates are provided in the cavity portion of the lens mounting area 11 in the vicinity of the adhesive application portions 22 and 23 and in symmetrical positions. Is used. Note that a plurality of (for example, four) lens holders 1 can be molded from the mold at a time. Hereinafter, this mold is referred to as “main mold”.

  The lens mounting portion 21 is formed around the diaphragm 26. The lens mounting unit 21 positions the objective lens 2 in the optical axis direction together with the flange (not shown) of the objective lens 2 by placing the objective lens 2. The adhesive application portions 22 to 25 are continuous so as to protrude from the outer periphery of the lens mounting portion 21 formed around the aperture 26 and the outer periphery of the aperture 26, and adjacent ones with respect to the center of the aperture 26 are symmetrical to each other. Is formed.

  In addition, an objective lens protection member mounting portion 27 is formed between the adhesive application portion 23 and the adhesive application portion 24, and an objective lens protection member is provided between the adhesive application portion 25 and the adhesive application portion 22. A mounting portion 28 is formed. Although not shown, the objective lens protection member attaching portions 27 and 28 are attached with an objective lens protection member for protecting the objective lens 2. This objective lens protection member is used to prevent the objective lens 2 from colliding with an optical recording medium such as an optical disk while an optical head having an objective lens driving device using the lens holder 1 is operating. It is provided so as to protrude from the upper surface. For this reason, the objective lens protection member is generally made of a soft material so as not to damage the surface of the optical recording medium even if it collides with the optical recording medium.

  As described above, in FIG. 1, among the four adhesive application portions 22 to 25, in the vicinity of the adhesive application portions 22 and 23 located in the vicinity of the front surface of the lens holder 1, Gate traces 29 and 30 are respectively shown at the positions. On the other hand, an objective lens protection member mounting part 27 is formed between the adhesive application part 23 and the adhesive application part 24, and an objective lens protection member is provided between the adhesive application part 25 and the adhesive application part 22. A mounting portion 28 is formed. From these two things, it can be said that the gate marks 29 and 30 are formed in the vicinity of the objective lens protection member attaching portions 27 and 28 formed in the vicinity of the lens mounting portion 21.

Hereinafter, the reason why the gate marks 29 and 30 are formed as described above, that is, the reason for using a mold capable of forming the resin molded product formed with the gate marks 29 and 30 will be described.
(1) First, the reason why the gate marks 29 and 30 are substantially the same height as the adhesive application portions 22 and 23, that is, the step is formed from the upper surface 11a of the lens mounting region 11 and is lowered by one step will be described. .
The mold gate is a part where high-temperature molten resin enters the mold from the molding machine. Therefore, even when taking out the resin molded product from the mold, the resin in the vicinity of the gate and the resin does not harden. It becomes a burr (convex part) as a product and may protrude from the surroundings. Therefore, even when the gate trace 29 or 30 becomes a burr, such a structure is employed so as not to protrude from the uppermost surface of the objective lens.

(2) Next, the reason for configuring the mold so that the gate marks 29 and 30 are formed in the vicinity of the objective lens protection member mounting portions 27 and 28 formed in the vicinity of the lens mounting portion 21 will be described.
If the structure shown in (1) is simply adopted, the thickness of the lens holder 1 must be reduced in order to form the step, which may deteriorate the moldability. is there. In this respect, the objective lens protection member attached to the objective lens protection member attachment portions 27 and 28 is, as described above, the objective lens 2 and the objective lens 2 while the optical head having the objective lens driving device using the lens holder 1 is operating. In order to prevent the optical recording medium such as an optical disk from colliding, it is provided so as to protrude from the uppermost surface of the objective lens. For this reason, the objective lens protection member is generally made of a soft material so as not to damage the surface of the optical recording medium even if it collides with the optical recording medium. Therefore, if the gate traces 29 and 30 are formed in the vicinity of the portion protruding from the upper surface 11a of the lens mounting area 11, even if the gate traces 29 and 30 protrude slightly as burrs, the optical disc or the like The optical recording medium does not collide. Further, by adopting such a structure, the step described in the above (1) can be lowered, and the portion where the lens holder 1 is thin can be reduced.

  In the lens holder 1, the wound drive coils are respectively inserted and fixed in the coil attachment regions 12 and 13. Furthermore, as will be described later with reference to FIGS. 4 and 5 in the second embodiment, the wire attachment regions 15 and 16 are each made of a conductive elastic body and are made of six suspension wires 6 having flexibility. One end side is configured to be fixed by soldering.

  The lens holder 1 is used for an optical recording / reproducing apparatus called a so-called ultra slim type (total thickness of the apparatus; about 9.5 mm, total thickness of the optical head; about 4.5 mm). Accordingly, the entire thickness of the lens holder 1 is about 3.05 mm, the width is about 11 mm, and the depth is about 4.5 mm.

  Moreover, each wall which comprises the lens holder 1 can thinn the thinnest part (minimum thickness part) to about 0.25 mm, and thinnest the thickest part (maximum thickness part) to about 0.7 mm. be able to. The reason why the minimum thickness portion and the maximum thickness portion are defined in this way is that the lens holder 1 cannot be molded with the required mechanical strength when each is thinner than this value. In addition, when the maximum thickness part is 1.0 mm or more, the moldability is good, but when the maximum thickness part is thinner than 1.0 mm, the ultra slim type optical recording / reproducing apparatus is configured. In the case of an optical head, there arises a problem that the present invention attempts to solve, in which the objective lens is inclined in the radial direction. The present invention solves the above problem when the maximum wall thickness of each wall constituting the lens holder 1 is 0.7 mm or more and 1.0 mm or less.

  Here, in the first embodiment, as a mold for molding the lens holder 1, the cavity portion of the lens mounting region 11 is positioned in the vicinity of the adhesive application portions 22 and 23 and in a symmetrical position. The reason why two gates having openings are used will be described.

First, an example of a specific method of the operation test will be described.
(1) For an objective lens driving device including a lens holder on which an objective lens is mounted, the inclination of the objective lens is measured as an initial posture based on the reflected light from the edge of the objective lens by an autocollimator at room temperature.
(2) The objective lens driving device that has undergone the process of (1) is housed together with a jig in a dryer having an internal temperature of about 75 ° C. for about 20 minutes.

(3) The objective lens driving device is taken out of the dryer, and the tilt of the objective lens is measured again by the autocollimator based on the reflected light from the edge of the objective lens.
(4) With respect to the objective lens driving device that has undergone the process of (3), when the temperature of the lens holder is measured with a radiation thermometer and becomes about 55 ° C., the autocollimator is used to reflect the reflected light from the edge of the objective lens. To measure the tilt of the objective lens.

  Next, the lens holder constituting the objective lens driving device to be measured is manufactured by the above-described mold, and any one of the adhesive application portions 22 and 23 is formed in the cavity portion of the lens mounting region 11 shown in FIG. It is manufactured by using a mold (hereinafter referred to as “comparative example”) having one gate opened in the vicinity of one. Here, FIG. 3 shows the result of measuring the tilt of the objective lens by the above-described operation test for the objective lens driving device using the lens holders respectively produced in the present mold and the comparative example.

  As can be seen from FIG. 3, in the case of the comparative example, the objective lens is tilted by about 13.7 minutes in the radial direction by performing the operation test. As a result of earnest examination on this point, the inventors have warped, cracked or distorted the lens holder due to differences in residual stress or resin density when molding the lens holder, and perform the above operation test. At this time, it is considered that this is because the lens holder becomes hot and the warp during the molding tries to return to the original shape.

  On the other hand, in the case of an objective lens driving device in which an objective lens is mounted on a lens holder molded using this mold, the objective lens is inclined only about 1 minute in the radial direction even if the above operation test is performed. . This is considered to be due to the following reasons. First, by providing the gate at a symmetrical position in the present mold, the flow of resin when molding the lens holder becomes symmetrical. Thereby, at the time of molding, the lens holder is less likely to be warped, cracked or distorted due to a difference in residual stress, resin density, or the like. Therefore, even when the lens holder becomes high temperature by performing the operation test, the return amount to the original shape from the warp during the molding is reduced compared to the conventional case.

  As described above, according to the first embodiment of the present invention, even when the lens holder 1 becomes high temperature, the objective lens mounted in the lens mounting area 11 hardly tilts in the radial direction, that is, the objective lens 2 ( (See FIG. 4). Thereby, the reliability of the optical head having the objective lens driving device using the lens holder 1 is improved. Therefore, since the light beam emitted from the laser diode constituting this optical head is correctly irradiated to the optical recording medium set in the optical recording / reproducing apparatus equipped with this optical head, data recording or recording on the optical recording medium is possible. Reproduction can be performed appropriately. As a result, the present invention is sufficiently applicable to an optical recording / reproducing apparatus that has been reduced in size, thickness, and weight to an ultra slim type or a lower type, or an optical recording / reproducing apparatus using a laser diode having a short light beam wavelength. Can be applied.

Embodiment 2. FIG.
FIG. 4 is a schematic perspective view showing the configuration of the objective lens driving device according to Embodiment 2 of the present invention, and FIG. 5 is a schematic perspective view of the configuration of the objective lens driving device shown in FIG. The objective lens driving device of this example includes a lens holder 1 having the configuration described in the first embodiment, an objective lens 2, a yoke base 3, a driving magnet 4, a driving coil 5, and a suspension wire 6. And a wire base 7 and a base substrate 8.

  The objective lens 2 is integrally formed by injection molding or extrusion molding using an olefin resin (for example, cycloolefin), an acrylic resin (for example, PMMA), or a methacrylic resin as a raw material. Some objective lenses 2 are formed by molding using a preform using optical glass as a raw material. The objective lens 2 has a substantially disk shape as a whole, and its lower surface is a spherical or aspherical convex curved surface that forms a lens surface. Although not shown, an annular flange (outer ring portion) is provided on the outer periphery of the lower surface of the objective lens 2. The objective lens 2 is fixed to the lens holder 1 with an adhesive 31. In FIG. 4, the adhesive 31 applied to the adhesive application unit 24 shown in FIG. 1 is not shown. An objective lens protection member 32 is attached to each of the objective lens protection member attachment portions 27 and 28.

  Further, the wound drive coils 5 are respectively inserted and fixed in the coil attachment regions 12 and 13 constituting the lens holder 1. The driving coil 5 is composed of, for example, an FP (fine pattern) coil. The yoke base 3, the drive magnet 4 and the drive coil 5 constitute a magnetic circuit, and each of the focus adjustment direction, tracking adjustment direction and skew adjustment direction with respect to the lens holder 1 on which the objective lens 2 is mounted. The driving force is generated.

  Further, the wire attachment regions 15 and 16 constituting the lens holder 1 are made of a conductive elastic body, and one end side of each of the flexible suspension wires 6 is fixed by soldering at predetermined intervals. . Each other end side of the suspension wire 6 is fixed to a predetermined position of the base substrate 8 attached to the wire base 7 by soldering. Accordingly, the lens holder 1 is cantilevered by the wire base 7 and the base substrate 8 via the suspension wire 6 and is elastically supported so as to be relatively displaceable with respect to the fixed portion including the wire base 7 and the base substrate 8. ing.

  Although not shown, one end of each driving coil 5 is soldered and electrically connected to one end of each of the six suspension wires 6. On the other hand, the other ends of the six suspension wires 6 are electrically connected to a lens driving circuit (not shown). That is, the suspension wire 6 has both a function as an elastic body (support body) for supporting the lens holder 1 and a function as a lead wire for supplying power to the driving coil 5. The suspension wire 6 may be another elastic body such as a leaf spring, a coil spring, or rubber.

  Thus, according to the second embodiment of the present invention, the objective lens driving device is configured using the lens holder 1 according to the first embodiment described above. Therefore, in the optical recording / reproducing apparatus equipped with the optical head using this objective lens driving device, even when the lens holder 1 is heated, the objective lens 2 mounted on the lens holder 1 hardly tilts in the radial direction. That is, the posture of the objective lens 2 can be kept constant. Thereby, the reliability of the optical head using this objective lens driving device is improved. Therefore, since the light beam emitted from the laser diode constituting this optical head is correctly irradiated to the optical recording medium set in the optical recording / reproducing apparatus equipped with this optical head, data recording or recording on the optical recording medium is possible. Reproduction can be performed appropriately. As a result, the present invention is sufficiently applicable to an optical recording / reproducing apparatus that has been reduced in size, thickness, and weight to an ultra slim type or a lower type, or an optical recording / reproducing apparatus using a laser diode having a short light beam wavelength. Can be applied.

Embodiment 3 FIG.
FIG. 6 is a schematic diagram showing a configuration of an optical recording / reproducing apparatus according to Embodiment 3 of the present invention. This optical recording / reproducing apparatus includes an optical head 41 using the objective lens driving apparatus according to the second embodiment, a spindle motor 42, a spindle motor driving circuit 43, a controller 44, a feed motor 45, and a feed motor. A driving circuit 46, a laser driving circuit 47, and a lens driving circuit 48 are roughly configured.

  The spindle motor drive circuit 43 drives the spindle motor 42 under the control of the controller 44 to rotate the optical recording medium 49. The controller 44 controls the spindle motor drive circuit 43, the feed motor drive circuit 46, the laser drive circuit 47, and the lens drive circuit 48 based on the photodetector detection signal supplied from the optical head 41, respectively.

  The feed motor drive circuit 46 drives the feed motor 45 under the control of the controller 44 to move the optical head 41 in the radial direction of the optical recording medium 49. The laser drive circuit 47 generates a laser drive signal for driving a laser diode (not shown) constituting the optical head 41 under the control of the controller 44 and supplies the laser drive signal to the optical head 41. The lens drive circuit 48 generates a lens drive signal for controlling the focusing, tracking, and tilt of the objective lens 2 (see FIG. 4) constituting the optical head 41 under the control of the controller 44, and supplies the lens drive signal to the optical head 41. To do.

  The controller 44 includes a focus servo tracking circuit 51, a tracking servo tracking circuit 52, a skew adjustment circuit 53, and a laser control circuit 54. The focus servo follow-up circuit 51 is a focus for focusing the light beam emitted from the optical head 41 on the data recording surface of the rotating optical recording medium 49 based on the photodetector detection signal supplied from the optical head 41. A servo signal is generated and supplied to the lens driving circuit 48.

  The tracking servo tracking circuit 52 determines the beam spot of the light beam emitted from the optical head 41 with respect to the eccentric signal track of the optical recording medium 49 based on the photodetector detection signal supplied from the optical head 41. A tracking servo signal for tracking is generated and supplied to the lens driving circuit 48. Based on the photodetector detection signal supplied from the optical head 41, the skew adjustment circuit 53 generates a skew adjustment signal for inclining the objective lens 2 (see FIG. 4) constituting the optical head 41 in the radial direction or the tangential direction. Generated and supplied to the lens driving circuit 48. The laser control circuit 54 generates an appropriate laser drive signal based on the recording condition setting data recorded on the optical recording medium 49 extracted from the photodetector detection signal supplied from the optical head 41.

  As described above, according to the third embodiment of the present invention, the optical recording / reproducing apparatus is configured by using the objective lens driving device according to the second embodiment described above. Therefore, in this optical recording / reproducing apparatus, even when the lens holder 1 of the objective lens driving device constituting the optical head 41 becomes high temperature, the objective lens 2 mounted on the lens holder 1 hardly tilts in the radial direction. The posture of the objective lens 2 can be kept constant. As a result, the reliability of the optical head 41 and thus the optical recording / reproducing apparatus is improved. Therefore, since the light beam emitted from the laser diode constituting the optical head 41 is correctly applied to the optical recording medium 49, data can be recorded or reproduced on the optical recording medium 49 appropriately. As a result, the present invention is sufficiently applied to an optical recording / reproducing apparatus that has been reduced in size, thickness, and weight to an ultra slim type or lower type, and an optical recording / reproducing apparatus that uses a laser diode having a short light beam wavelength. Can be applied.

Embodiment 4 FIG.
In the first to third embodiments described above, an example of an optical head provided with only one light source or an optical recording / reproducing apparatus provided with only one optical head has been described. However, the present invention is not limited to this. The present invention can also be applied to an optical head provided with a plurality of light sources and an optical recording / reproducing apparatus provided with a plurality of optical heads. Such an optical head and an optical recording / reproducing apparatus are disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-295982.

As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments, and the design can be changed without departing from the scope of the present invention. Is included in the present invention.
For example, in the above-described first embodiment, as a mold for molding the lens holder 1, the cavity portion of the lens mounting region 11 is positioned in the vicinity of the adhesive application portions 22 and 23 and in a symmetrical position. Although an example is shown in which two gates are used, the present invention is not limited to this. As a mold for molding the lens holder 1, for example, any of the following may be used.

(1) A structure in which two gates are provided in the cavity portion of the lens mounting region 11 in the vicinity of the adhesive application portions 24 and 25 and in symmetrical positions.
(2) In the cavity portion of the lens mounting region 11, two gates are provided in the vicinity of the adhesive application portions 23 and 25 in symmetrical positions.
(3) In the cavity portion of the lens mounting area 11, two gates are provided in the vicinity of the adhesive application portions 22 and 24 in symmetrical positions.
(4) In the cavity portion of the lens mounting region 11, four gates are provided in the vicinity of the adhesive application portions 22 to 25 at symmetrical positions.

It is a schematic perspective view which shows the structure of the lens holder which concerns on Embodiment 1 of this invention. It is the schematic perspective view which looked at the structure of the lens holder shown in FIG. 1 from the back side. It is a figure which shows an example of the result of the operation | movement test of the objective lens drive device which mounts an objective lens in the lens holder shape | molded by this metal mold | die and the metal mold | die of a comparative example, respectively. It is a schematic perspective view which shows the structure of the objective lens drive device which concerns on Embodiment 2 of this invention. It is the schematic perspective view which looked at the structure of the objective-lens drive device shown in FIG. 4 from the back side. It is the schematic which shows the structure of the optical recording / reproducing apparatus which concerns on Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens holder 2 Objective lens 3 Yoke base 4 Driving magnet 5 Driving coil 6 Suspension wire 7 Wire base 8 Base substrate 11 Lens mounting area 11a Upper surface 12, 13 Coil mounting area 15, 16 Wire mounting area 21 Lens mounting part 22 ~ DESCRIPTION OF SYMBOLS 25 Adhesive application part 26 Aperture 27, 28 Objective lens protection member attachment part 29, 30 Gate trace 31 Adhesive 32 Objective lens protection member 41 Optical head 42 Spindle motor 43 Spindle motor drive circuit 44 Controller 45 Feed motor 46 Feed motor drive circuit 47 Laser driving circuit 48 Lens driving circuit 49 Optical recording medium 51 Focus servo tracking circuit 52 Tracking servo tracking circuit 53 Skew adjustment circuit 54 Laser control circuit

Claims (4)

An objective lens is mounted at the center, and is a lens holder that is elastically supported by the fixed portion so as to be relatively displaceable.
A mold provided with a plurality of gates at symmetrical positions via a lens mounting portion on which the objective lens is mounted is integrally molded by injecting resin from the plurality of gates , thickness is not more 0.25mm or more, Ri thickness of the thickest part Do the following resin molding 1.0 mm,
An objective lens protection member for protecting the objective lens, wherein a plurality of gate traces in the resin molded product corresponding to the plurality of gates provided in the mold are formed in the vicinity of the lens mounting portion. A lens holder formed in the vicinity of the mounting portion . An objective lens driving device comprising the lens holder according to claim 1 . An optical head comprising the objective lens driving device according to claim 2 . An optical recording / reproducing apparatus comprising the optical head according to claim 3 .

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