JP4064263B2 - Optical pickup device and optical disk device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disk device, and more particularly to an optical pickup device having a mechanism system for correcting spherical aberration of an optical pickup.
[0002]
[Prior art]
Optical discs have the advantages of being rewritable, medium replaceable, and large capacity, and many standards such as CD, CD-R, CD-RW, DVD-RW, and DVD-RAM have been used. In recent years, such optical discs are required to have higher recording density, larger capacity, and smaller size.
[0003]
In order to increase the recording signal density in such an optical disc, the spot diameter of the laser beam focused on the disc recording surface is reduced in the optical system (optical pickup) of the optical disc apparatus that records and reproduces the optical disc. There is a need to make it smaller. In order to reduce the spot diameter of the laser, a general technique is to increase the NA (aperture ratio) of the objective lens and shorten the wavelength of the laser emitted from the light source.
[0004]
However, since the spherical aberration in the objective lens increases in proportion to the fourth power of the NA of the objective lens and the thickness of the optically transparent layer of the optical disk, increasing the NA of the objective lens to reduce the laser spot diameter. As a result, there arises a problem that the spherical aberration becomes larger than that of a conventional NA objective lens. For example, the NA of a conventional objective lens is about 0.6, but the spherical aberration when the NA of the objective lens is 0.8 to 0.9 is 3 to 5 times that of NA 0.6. To increase.
[0005]
In order to prevent an increase in the amount of spherical aberration in the objective lens, a method of reducing the thickness of the optically transparent layer of the optical disk can be considered. However, in this case, it is necessary to reduce the variation in the thickness of the optical transparent layer in the same manner, and there is a manufacturing limit. For example, when the thickness of the optically transparent layer of the optical disk used in the case of using a conventional objective lens with an NA of 0.6 is further reduced (by 1/6) to 0.1 mm If the variation in the thickness of the optical transparent layer is not reduced to 1/6 with respect to the variation in the thickness of the conventional optical transparent layer, the spherical aberration will increase. However, it is difficult with the current technology to reduce the thickness of the optical transparent layer to 1/6 and suppress the variation in the thickness of the optical transparent layer to 1/6.
[0006]
Further, as a method of increasing the NA while avoiding an increase in spherical aberration in the objective lens, there is a method of correcting spherical aberration using two correction lenses. In this method, for example, as disclosed in Patent Document 1, one correction lens is used as a correction lens that can move in the optical axis direction, and a plurality of types of optical disks having different optical transparent layer thicknesses are used. Thus, it is possible to correct the spherical aberration by changing the interval between the two correction lenses.
[0007]
However, in the method of Patent Document 1, when the correction lens is moved in the optical axis direction, the correction lens may be tilted or displaced with respect to the optical axis. The ability to correct the aberration of the beam spot is reduced, and good recording and reproduction cannot be performed.
[0008]
For such inclination and displacement of the correction lens, a design clearance is provided between the guide shaft that regulates the moving direction of the head carriage that holds the correction lens and the shaft holder (guide shaft hole) of the head carriage. It is caused by being. In other words, rattling between the guide shaft and the shaft holder causes the inclination and displacement of the correction lens.
[0009]
Although the allowable amount of the correction lens tilt and the positional deviation amount varies depending on the optical design, as an example, the allowable amount of the correction lens inclination is 5 to 10 ′ (minutes) or less, and the feed position deviation amount with respect to the optical axis is as follows. 20 μm or less. Therefore, there is a need for a highly accurate aberration correction lens optical axis direction feed mechanism and guide mechanism.
[0010]
Therefore, for example, Patent Document 2 discloses a technique of a guide mechanism that prevents a rotation moment around a guide shaft that guides the movement of the head carriage from being generated with respect to the head carriage that holds the lens when the lens is moved. Has been. Specifically, in a structure having a lead screw that applies a moving force to the head carriage and an engaging pin for moving the head carriage that is provided on the head carriage and is engaged with the lead screw, at the contact point between the engaging pin and the lead screw. The guide shaft is configured such that the approximate center of the guide shaft is positioned on the substantially extended line in the tangential direction. Thereby, it is possible to reduce lens displacement caused by the rotation of the head carriage around the guide shaft.
[0011]
Further, for example, in Patent Document 3, a countershaft for restricting the rotation of the head carriage is provided, and the countershaft and the recess of the recess are arranged so that the countershaft and the recess on the head carriage side supporting the countershaft are in stable contact. A technique of a guide mechanism that applies a load to a contact portion is disclosed. Thereby, the influence by the play between a countershaft and the recessed part which supports it can be reduced.
[0012]
[Patent Document 1]
JP-A-9-197264 (published July 31, 1997)
[0013]
[Patent Document 2]
Patent No. 2568197 (released on November 7, 1988)
[0014]
[Patent Document 3]
Japanese Patent No. 3324544 (published on September 14, 2000)
[0015]
[Problems to be solved by the invention]
However, the guide mechanism of Patent Document 2 suppresses the generation of rotational moment around the guide shaft in the head carriage and reduces the displacement and tilt of the lens. However, the guide mechanism exists between the guide shaft and the shaft holder. There is a limit to the effect of reducing the displacement and tilt of the lens.
[0016]
For this reason, particularly when the moving direction is reversed, the correction lens 105 moves in a direction opposite to the moving direction of the arm 103 as shown in FIGS. 6A and 6B in the initial minute displacement. There is a problem that the feeding position shift of the correction lens occurs. This positional deviation increases as the distance between the main shaft 101 and the objective lens center position increases.
[0017]
In addition, when a method of indirectly detecting the position of the correction lens 105 based on the number of rotations of a motor (not shown) that drives the lead screw 104 is employed, there is a problem that the position cannot be accurately detected. .
[0018]
In order to improve this phenomenon in the guide mechanism of Patent Document 2, it is conceivable to increase the length of the main shaft or reduce the clearance between the main shaft and the shaft hole.
[0019]
However, since the correction lens 105 is incorporated in the optical pickup device, increasing the length of the main shaft leads to increasing the size of the optical pickup device itself. In addition, there is a manufacturing limit to reducing the clearance between the main shaft and its shaft hole, and there is a limit to improvement.
[0020]
Further, in the conventional guide mechanism as shown in Patent Documents 2 and 3, when this is used as a correction lens feed mechanism in a configuration in which a correction lens movable in the optical axis direction as shown in Patent Document 1 is provided, There are the following problems.
[0021]
In the case of a correction lens driving mechanism using a conventional guide mechanism, as shown in FIGS. 6A and 6B, a correction lens 105 exists between the main shaft 101 and the sub shaft 102. The size of the correction lens driving mechanism is increased. Here, since the correction lens driving mechanism is provided in the housing of the optical pickup, an increase in the size is a big design problem.
[0022]
Further, in the arm 103 that engages with the lead screw and transmits the rotation of the lead screw as the moving force of the correction lens, the position where the load is generated on the arm 103 when the arm moves is outside the space between the main shaft 101 and the sub shaft 102. Located in. For this reason, the load applied to the main shaft 101 and the sub shaft 102 becomes large, which becomes a factor that hinders downsizing of the driving device.
[0023]
That is, in the conventional guide mechanism shown in FIG. 7, when the pressing force of the arm 103 is N, the load applied to the main shaft 101 is N1, and the load applied to the sub shaft 102 is N2, the distance from the pressing point to the main shaft is L1, When the distance between the main shaft and the sub shaft is L2,
The balance of moment is N × L1 = N2 × L2
The balance of power is N1 = N + N2.
It becomes. Therefore, the total load applied to the main shaft 101 and the sub shaft 102 is
N1 + N2 = N × (1 + 2 × L1 / L2)
Thus, since the total load N1 + N2 applied to the main shaft 101 and the sub shaft 102 is larger than the pressing force N, the frictional force also increases accordingly.
[0024]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an optical pickup device including a correction lens driving mechanism that can prevent a shift in the feed position when the moving direction is reversed and is suitable for downsizing, and the optical pickup device. An object of the present invention is to provide an optical disk device having an optical pickup device.
[0025]
[Means for Solving the Problems]
In order to solve the above problems, an optical pickup device according to the present invention includes a light source, an objective lens, and a correction lens that is disposed between the light source and the objective lens and is movable in the optical axis direction of the beam light emitted from the light source. And a lens holding means for holding the correction lens and a sliding holding means for holding the lens holding means so as to be slidable in the optical axis direction. The means is slidably held in a guide hole provided in the sliding holding means, and the guide hole of the sliding holding means has a notch parallel to the optical axis. The lens holding means has a convex part that fits into the notch part.
[0026]
According to the above configuration, the lens holding unit is slidably held in the guide hole of the sliding holding unit, and the correction lens is moved along the optical axis direction by sliding the lens holding unit. Can be made.
[0027]
Further, at this time, the guide hole of the sliding holding means is provided with a notch, and the lens holding means slides and moves with the notch and the convex part fitted together. The rotation around the center of the movement axis can be restricted with a very simple configuration, and the correction lens moving mechanism can be downsized.
[0028]
In the optical pickup device, it is preferable that the sliding holding means has a configuration in which an outer peripheral surface around the optical axis is opened at the notch.
[0029]
According to said structure, since the guide hole of the said slide holding means is an open state in the notch part, it is possible to improve the manufacture precision of a notch part and a convex part rather than the case where it is not an open state. It becomes. Thereby, it is possible to suppress the rotation of the lens holding unit and the inclination with respect to the optical axis direction due to the clearance between the convex portion of the lens holding unit and the notch of the sliding holding unit.
[0030]
Moreover, in the said optical pick-up apparatus, it is preferable that the drive force from a drive source is transmitted via a convex part.
[0031]
Since the outer peripheral surface around the optical axis is opened at the notch provided in the guide hole, the slide holding means has an outer peripheral surface side of the convex portion fitted into the notch, It can be slidably moved in the optical axis direction while being exposed at the notch.
[0032]
Here, according to the above configuration, the driving force for moving the lens holding means is transmitted via the convex portion exposed in the notch, and the driving force can be easily applied to the lens with a simple configuration. It can be transmitted to the holding means. Thereby, the lens holding means can be reduced in size.
[0033]
Further, in the optical pickup device, a lead screw that is arranged in parallel with the optical axis of the beam light emitted from the light source and is rotated by a driving source, and is fixed to a convex portion of the lens holding means, the lead screw, An arm that is engaged to convert the rotation of the lead screw into a linear motion in the optical axis direction and transmits it to the lens holding means, and the contact surface at the contact point between the arm and the lead screw is a convex of the lens holding means. It can comprise so that it may become substantially parallel with respect to the contact surface of a part and the notch part of the said slide holding means.
[0034]
According to said structure, the contact surface in the contact of the said arm and the said lead screw is with respect to the contact surface (rotation control surface) of the convex part of the said lens holding means, and the notch part of the said sliding holding means. By being substantially parallel, the pressing force of the arm acts perpendicularly to the rotation restricting surface. Thereby, the pressing force of the arm acts so as to suppress the rattling on the rotation restricting surface, and the shift at the time of movement of the correction lens can be reduced.
[0035]
In the optical pickup device, the contact point between the arm and the lead screw is lens Perpendicular to the contact surface between the convex part of the holding means and the notch part of the sliding holding means and parallel to the optical axis Above lens It can be configured to be positioned between a plane passing through the contact point between the convex portion of the holding means and the cutout portion of the sliding holding means and a plane parallel to the plane and passing through the axial center of the correction lens.
[0036]
According to the above configuration, the total load applied to the contact portion between the lens holding unit and the sliding holding unit is equal to the pressing force acting at the contact point between the arm and the lead screw, and the range holding unit and the sliding unit are slid. It is possible to suppress such a problem that the load at the contact portion with the moving holding means increases and the frictional force generated when the lens holding means moves is increased.
[0037]
In the optical pickup device, the guide hole of the sliding holding unit and the lens holding unit have a substantially circular cross-sectional shape in a plane perpendicular to the optical axis, and the axial center position of the lens holding unit is The axial center position of the correction lens may be substantially coincident.
[0038]
According to the above configuration, even if the lens holding means is inclined in the optical axis direction due to the clearance between the lens holding means and the guide hole of the sliding holding means, The amount of misalignment of the correction lens held in the optical axis direction can be minimized.
[0039]
Further, according to the above configuration, even if the lens holding unit is rotated around the axis of the lens holding unit when the lens holding unit is moved, the correction lens only rotates around the axis of the correction lens itself. Therefore, the rotation radius of the correction lens in such a case can be minimized, and the shift amount of the correction lens feed position can be minimized.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the optical pickup device of the present invention will be described below with reference to FIGS.
[0041]
2A and 2B are configuration diagrams of the optical pickup device according to the present embodiment, where FIG. 2A is a top view and FIG. 2B is a side view. This optical pickup device includes a light source 1 composed of a semiconductor laser, a hologram 2, a light detection device 3 that receives a signal diffracted by the hologram 2, a collimator lens 4, a movable correction lens (correction lens) 5, and a fixed correction lens. 6, a rising mirror 7, an objective lens 8, an objective lens actuator 9, a motor (driving source) 10, a gear unit 11, an optical pickup housing 20 for attaching optical components integrally and moving in the disk radial direction, etc. Has been.
[0042]
In the optical pickup device, the light generated by the light source 1 passes through the hologram 2 as 0th-order diffracted light, and further passes through the collimating lens 4 to become a parallel light beam. The light that has passed through the collimator lens 4 then passes through the movable side correction lens 5 and the fixed side correction lens 6. At that time, the movable side correction lens 5 is moved, and the distance between the movable side correction lens 5 and the fixed side correction lens 6 is changed, so that the light passing through the movable side correction lens 5 and the fixed side correction lens 6 is collimated. Can be converted to light, convergent light, or divergent light. Thereby, the spherical aberration on the recording surface 41 of the optical disc 40 can be corrected.
[0043]
The light that has passed through the fixed-side correction lens 6 is converged by the objective lens 8 after being deflected by 90 ° by the rising mirror 7 and irradiated onto the optical disc 40. The light irradiated on the optical disc 40 passes through the optical transparent layer of the optical disc 40 and is condensed on the recording surface 41 of the optical disc 40. The objective lens 8 is subjected to focus servo and radial servo by the objective lens actuator 9, so that the positional relationship between the optical disc 40 and the objective lens actuator 9 is kept constant even when there is a surface shake or disturbance of the optical disc 40. It has become.
[0044]
The reflected light from the recording surface 41 of the optical disc 40 then follows the reverse optical path and passes through the objective lens 8, the raising mirror 7, the fixed side correction lens 6, the movable side correction lens 5, and the collimating lens 4. The reflected light is diffracted when it reaches the hologram 2. The light detection device 3 detects a focus servo signal, a radial servo signal, and a spherical aberration signal using the diffracted light.
[0045]
Next, a lens moving mechanism that moves the movable correction lens 5 as a configuration having the characteristic part of the present invention will be described with reference to FIGS. 1 and 3.
[0046]
As shown in FIG. 1, the lens moving mechanism includes a motor 10, a gear unit 11, a lead screw 32, a lens guide shaft (lens holding means) 30, an arm 31, and a guide holder (sliding holding means) 34. ing. The motor 10 is a driving source that provides a driving force for moving the movable correction lens 5. The gear unit 11, the lead screw 32, the lens guide shaft 30, the arm 31, and the guide holder 34 transmit the driving force supplied from the motor 10 to the movable side correction lens 5 and moves the movable side correction lens 5 in the optical axis direction. It is a member for making it.
[0047]
In the lens moving mechanism, the motor 10, the gear unit 11, the lead screw 32, and the guide holder 34 are fixed to the optical pickup housing 20. The lens guide shaft 30 is a member that holds the movable correction lens 5 and is slidably held in a guide hole 34 a formed in the guide holder 34. The arm 31 is integrally attached to the lens guide shaft 30, and converts the rotation of the lead screw 32 into a linear motion and transmits it to the lens guide shaft 30.
[0048]
In the lens moving mechanism configured as described above, when the motor 10 rotates, the gear unit 11 integrally formed with the motor 10 decelerates the rotation speed and rotates the lead screw 32 attached to the final stage of the gear unit 11. Let The lead screw 32 is formed with a spiral feed groove, and an engaging portion provided at one end of the arm 31 is engaged with the feed groove. For this reason, when the lead screw 32 rotates, the engaging portion moves along the feed groove, and the rotation of the lead screw 32 is converted into a linear movement of the arm 31.
[0049]
Since the other end of the arm 31 is attached to the lens guide shaft 30, the linear movement of the arm 31 is transmitted as the movement of the lens guide shaft 30. At this time, the lens guide shaft 30 slides and moves within a guide hole 34a formed in the guide holder 34, and the moving direction is parallel to the optical axis of the light passing through the optical system.
[0050]
As described above, in the lens moving mechanism, the lens guide shaft 30 that holds the movable correction lens 5 is moved by the rotation of the motor 10 to adjust the position of the movable correction lens 5. At this time, for example, assuming that the gear reduction ratio of the gear unit 11 is 1/70 and the pitch of the lead screw 32 is 0.3 mm, the movable side correction lens 5 moves 4.3 μm every time the motor 10 rotates once.
[0051]
The motor shaft of the motor 10 is provided with a magnet (not shown) magnetized with two poles for detecting the rotation speed and a hall element (not shown) for discriminating between the S pole and the N pole. The position of the movable correction lens 5 can be detected by detecting the rotational speed of the motor with these magnets and hall elements.
[0052]
Next, the lens guide shaft 30 and the guide holder 34 in the lens moving mechanism will be described. The movable correction lens 5 is held by a lens guide shaft 30, and the lens guide shaft 30 is held by a guide holder 34 so as to be movable in the optical axis direction.
[0053]
Therefore, as shown in FIGS. 3A and 3B, the guide holder 34 has a guide hole 34a having an axis parallel to the optical axis direction, and the lens guide shaft 30 is in the guide hole 34a. It is slidably held by. Further, both the inner surface of the guide hole 34a of the guide holder 34 and the outer surface of the lens guide shaft 30 have a substantially circular cross-sectional shape perpendicular to the optical axis. Further, the diameter of the inner peripheral surface of the guide hole 34 a of the guide holder 34 is slightly smaller than the diameter of the outer peripheral surface of the lens guide shaft 30 so that the lens guide shaft 30 slides smoothly in the guide hole 34 a of the guide holder 34. Clearance is provided so as to increase.
[0054]
Further, the guide hole 34a of the guide holder 34 is not provided with a completely closed circle but is provided with a notch 34b in a part thereof in the circumferential direction. Further, the lens guide shaft 30 is provided with a convex portion 30a that fits into the cutout portion 34b. That is, the lens guide shaft 30 slides in a state in which the convex portion 30a is fitted to the notch portion 34b of the guide holder 34, so that the rotation of the lens guide shaft 30 around the optical axis is restricted. It has become.
[0055]
In addition, since the guide hole 34a of the guide holder 34 is in an open state at the cutout portion 34b, the manufacturing accuracy of the cutout portion 34b and the convex portion 30a can be improved as compared with the case where the guide hole 34a is not open. That is, the clearance between the convex part 30a and the notch part 34b can be reduced. As a result, it is possible to reduce the amount of inclination of the guide holder 34 relative to the optical axis direction and the amount of rotation around the optical axis due to the clearance between the convex portion 30a and the notch 34b.
[0056]
Here, for example, the lens guide shaft 30 may be formed integrally with the convex portion 30a using a resin material having high slidability (for example, PPS, liquid crystal polymer, etc.), or the lens guide shaft 30 may be formed. It may be made of a metal such as Al or SUS, and the slidability of the convex portion 30a may be improved by a method such as applying a coating having high slidability (for example, DLC coating) on the outer peripheral portion thereof. . Similarly, the slidability of the notch 34b can be improved for the guide holder 34 as well.
[0057]
A lead screw is provided on a surface that is one end of the convex portion 30 a of the lens guide shaft 30. 32 An arm 31 made of an elastic material having an engaging portion for engaging with is attached. The engagement portion provided at the tip of the arm 31 is preferably a rack shape, so that it can be engaged with the feed groove of the lead screw 32 with high accuracy and feed without play can be achieved. The engaging portion is made of a metal or a resin having high slidability, and is formed by bonding or integrally forming with the arm 31.
[0058]
Further, since the arm 31 is attached to one end portion of the convex portion 30 a that restricts the rotation of the lens guide shaft 30, another arm for restricting the rotation of the arm 31 and the lens guide shaft 30 with respect to the lens guide shaft 30 is provided. It is not necessary to attach the members to different places, and the mechanism can be miniaturized.
[0059]
Furthermore, as shown in FIG. 4, the cross section seen from the optical axis direction of the arm 31 is substantially L-shaped. Further, the arm 31 functions as a leaf spring for pressing the engaging portion toward the center of the lead screw 32.
[0060]
The contact portion between the arm 31 and the lead screw 32 is the arm 31 and the lead screw. 32 The contact surface 36 at the contact point (pressing point) is substantially parallel to the contact surface (rotation restricting surface 37) between the convex portion 30a of the lens guide shaft 30 and the notch portion 34b of the guide holder 34. It is configured. As a result, the pressing force of the arm 31 acts perpendicularly to the rotation restricting surface 37. The position where the pressing point is located is a straight line that is perpendicular to the rotation restricting surface 37 and passes through a contact point (rotation restricting portion) between the convex portion 30a of the lens guide shaft 30 and the notch 34b of the guide holder 34, and It is configured to be positioned between a straight line parallel to the straight line and perpendicular to the rotation center of the lens guide shaft 30.
[0061]
In this case, the pressing force of the arm 31 is N, and the load applied to the contact point between the lens guide shaft 30 and the guide holder 34 that is perpendicular to the rotation restricting surface 37 and perpendicular to the rotation center of the lens guide shaft 30 is N1. If the load applied to the rotation restricting part is N2, the balance of force is
N = N1 + N2
Thus, the total load applied to the center position of the lens guide shaft 30 and the rotation restricting portion is equal to the pressing force N. Further, since the N1 and the N2 always act in the same direction, the N1 and the N2 are smaller than the pressing force N. That is, the rotation restricting portion and the convex portion 30a of the lens guide shaft 30 can always be brought into contact with each other with a constant frictional force smaller than the pressing force N.
[0062]
Furthermore, if the distance from the pressing point to the straight line passing through the center of the lens guide axis is L1, and the distance from the pressing point to the straight line passing through the rotation restricting portion is L2,
The moment balance is
N × L1 = N2 × (L1 + L2)
And, when you organize this,
N2 = L1 × N / (L1 + L2)
It becomes.
[0063]
Therefore, by changing the position of the contact portion between the arm 31 and the lead screw 32 and changing the size of L1, the load N2 generated in the rotation restricting portion can be changed. As a guideline for this load, it is more desirable to set the load so that the contact state between the rotation restricting portion and the convex portion 30a of the lens guide shaft 30 is not lost depending on the moving direction of the lens guide shaft.
[0064]
In this embodiment, as shown in FIGS. 1 and 3, the rotation center position of the lens guide shaft 30 and the center position of the movable correction lens 5 are substantially matched.
[0065]
For this reason, even if the lens guide shaft 30 is inclined in the optical axis direction due to the clearance between the lens guide shaft 30 and the guide hole 34 a of the guide holder 34, it is movable within the lens guide shaft 30. The amount of positional deviation of the side correction lens 5 in the optical axis direction can be minimized.
[0066]
Even when the lens guide shaft 30 is rotated when the moving direction is reversed (which may occur when the sliding member constituting the rotation restricting portion is worn due to repeated use over a long period of time), the movable side The correction lens 5 rotates around the center position of the movable side correction lens 5. Therefore, when the lens guide shaft 30 is rotated when the moving direction is reversed, it is movable. ~ side The radius of rotation of the correction lens 5 can be minimized. For this reason, it is possible to minimize the shift amount of the feed position of the movable side correction lens 5 when the moving direction is reversed.
[0067]
The optical pickup device according to the present embodiment is provided as means for reading information from or writing to an optical disk in an optical disk apparatus that records or reproduces information on the optical disk. A configuration example of such an optical disc apparatus is shown in FIG.
[0068]
As shown in FIG. 5, the optical disk apparatus rotates and drives the optical disk 40 by a spindle motor 51, and writes or reads information on the optical disk 40 by the optical pickup apparatus 50 according to the present embodiment. The control of the optical pickup device 50 and the spindle motor 51 is performed by the control unit 52. The control unit 52 controls driving of a signal control unit 52 a that controls a signal for writing or reading information from the optical pickup device 50 to the optical disc 40, a spindle motor 51, a servo system of the optical pickup device 50, and the like. A drive control unit 52b and the like are included.
[0069]
【The invention's effect】
As described above, the optical pickup device of the present invention includes the lens holding unit that holds the correction lens, and the sliding holding unit that holds the lens holding unit so as to be slidable in the optical axis direction. The lens holding means is slidably held in a guide hole provided in the sliding holding means, and the guide hole of the sliding holding means is a notch portion parallel to the optical axis. The lens holding means has a convex part that fits into the notch part.
[0070]
Therefore, the lens holding means is slidably held in the guide hole of the sliding holding means, and the lens holding means is fitted with a notch portion and a convex portion provided in the guide hole of the sliding holding means. Slide and move in the state. For this reason, it is possible to regulate the rotation of the lens holding means around the moving axis center with an extremely simple configuration, and it is possible to reduce the size of the correction lens moving mechanism.
[0071]
In the optical pickup device, it is preferable that the sliding holding means has a configuration in which an outer peripheral surface around the optical axis is opened at the notch.
[0072]
Therefore, the cutout portion and the convex portion are more than in the case where the outer peripheral surface around the optical axis in the cutout portion is not released. Production accuracy As a result, the amount of inclination of the correction lens with respect to the optical axis direction and the amount of rotation around the optical axis due to the clearance between the convex portion and the notch can be reduced.
[0073]
Moreover, in the said optical pick-up apparatus, it is preferable that the drive force from a drive source is transmitted via a convex part.
[0074]
Therefore, the driving force for moving the lens holding means is transmitted through the convex portion exposed at the notch, and the driving force can be easily transmitted to the lens holding means with a simple configuration. it can. As a result, the lens holding means can be reduced in size.
[0075]
Further, in the optical pickup device, a lead screw that is arranged in parallel with the optical axis of the beam light emitted from the light source and is rotated by a driving source, and is fixed to a convex portion of the lens holding means, the lead screw, An arm that is engaged to convert the rotation of the lead screw into a linear motion in the optical axis direction and transmits it to the lens holding means, and the contact surface at the contact point between the arm and the lead screw is a convex of the lens holding means. It can comprise so that it may become substantially parallel with respect to the contact surface of a part and the notch part of the said slide holding means.
[0076]
Therefore, the pressing force of the arm acts perpendicularly to the rotation restricting surface, whereby the pressing force of the arm acts to suppress the rattling on the turning restricting surface, and the correction lens shifts when moving. There is an effect that can be reduced.
[0077]
In the optical pickup device, the contact point between the arm and the lead screw is perpendicular to the contact surface between the convex portion of the holding means and the notch portion of the sliding holding means and parallel to the optical axis. It can be configured to be positioned between a plane passing through the contact point between the convex portion and the cutout portion of the sliding holding means and a plane parallel to the plane and passing through the axial center of the correction lens.
[0078]
Therefore, the total load applied to the contact portion between the lens holding means and the sliding holding means becomes equal to the pressing force acting at the contact point between the arm and the lead screw, and the range holding means and the sliding holding means There is an effect that it is possible to suppress such a problem that the load at the contact portion increases and the frictional force generated when the lens holding means moves is increased.
[0079]
In the optical pickup device, the guide hole of the sliding holding unit and the lens holding unit have a substantially circular cross-sectional shape in a plane perpendicular to the optical axis, and the axial center position of the lens holding unit is The axial center position of the correction lens may be substantially coincident.
[0080]
Therefore, even if the lens holding means is inclined in the optical axis direction due to the clearance between the lens holding means and the guide hole of the sliding holding means, the correction held in the lens holding means. There is an effect that the amount of displacement of the lens in the optical axis direction can be minimized.
[0081]
In addition, even if the lens holding means rotates around the axis of the lens holding means, the correction lens only rotates around the axis of the correction lens itself, thereby minimizing the shift amount of the correction lens feed position. The effect that it can be said.
[Brief description of the drawings]
FIGS. 1A and 1B are a top view and a front view of a main part of a correction lens driving unit mounted on an optical pickup device of the present invention.
FIGS. 2A and 2B are a top view and a side view of main parts of an optical pickup device of the present invention.
FIGS. 3A and 3B are a perspective view and an exploded perspective view of a main part of a correction lens driving unit mounted in the optical pickup device of the present invention. FIGS.
FIG. 4 is a cross-sectional view in a cross section perpendicular to a moving direction of a correction lens driving unit mounted on an optical pickup device of the present invention.
FIG. 5 is a block diagram showing a configuration example of an optical disc apparatus equipped with the optical pickup device of the present invention.
FIGS. 6A and 6B are diagrams illustrating operations at the moment when the moving direction is reversed when a conventional guide mechanism is used. FIGS.
FIG. 7 is a diagram illustrating a pressing force, a load applied to a main shaft, and a sub shaft in a conventional guide structure.
[Explanation of symbols]
1 Light source
5 Movable correction lens (correction lens)
6 Fixed correction lens
8 Objective lens
10 Motor (drive source)
30 Lens guide shaft (lens holding means)
30a Convex
31 arms
32 Lead screw
33 Convex
34 Guide holder (sliding holding means)
34a Guide hole
34b Notch
37 Rotation restriction surface
40 Optical disc

Claims (4)

In an optical pickup device including a light source, an objective lens, and a correction lens that is arranged between the light source and the objective lens and is movable in the optical axis direction of the beam light emitted from the light source.
Lens holding means for holding the correction lens;
Sliding holding means for holding the lens holding means so as to be slidable in the optical axis direction,
The lens holding means is slidably held in a guide hole provided in the slide holding means, and the guide hole of the slide holding means has a notch parallel to the optical axis. The lens holding means has a convex part that fits into the notch part ,
The sliding holding means has an outer peripheral surface around the optical axis opened at the notch,
A lead screw that is arranged in parallel to the optical axis of the beam light emitted from the light source and is rotated by a driving source, and is fixed to the convex portion of the lens holding means, and is engaged with the lead screw to rotate the lead screw. An arm that converts to linear movement in the direction of the optical axis and transmits it to the lens holding means,
The contact surface at the contact point between the arm and the lead screw is configured to be substantially parallel to the contact surface between the convex portion of the lens holding means and the notch portion of the slide holding means. A characteristic optical pickup device. In an optical pickup device including a light source, an objective lens, and a correction lens that is arranged between the light source and the objective lens and is movable in the optical axis direction of the beam light emitted from the light source.
Lens holding means for holding the correction lens;
Sliding holding means for holding the lens holding means so as to be slidable in the optical axis direction,
The lens holding means is slidably held in a guide hole provided in the slide holding means, and the guide hole of the slide holding means has a notch parallel to the optical axis. The lens holding means has a convex part that fits into the notch part,
The sliding holding means has an outer peripheral surface around the optical axis opened at the notch,
A lead screw that is arranged in parallel to the optical axis of the beam light emitted from the light source and is rotated by a driving source, and is fixed to the convex portion of the lens holding means, and is engaged with the lead screw to rotate the lead screw. An arm that converts to linear movement in the direction of the optical axis and transmits it to the lens holding means,
A contact point between the arm and the lead screw is perpendicular to the contact surface between the convex portion of the lens holding means and the cutout portion of the sliding holding means and parallel to the optical axis, and is slidably held with the convex portion of the lens holding means. It is configured to be located between a plane passing through the point closest to the axial center of the correction lens in a contact area with the notch of the means and a plane parallel to the plane and passing through the axial center of the correction lens An optical pickup device characterized by that. The guide hole of the sliding holding means and the lens holding means have a substantially circular cross-sectional shape in a plane perpendicular to the optical axis,
3. The optical pickup device according to claim 1, wherein an axial center position of the lens holding unit and an axial center position of the correction lens substantially coincide with each other. Optical disk apparatus characterized by comprising an optical pickup device according to any one of 3 to the first aspect.

Images