JP3238337B2 - Objective lens driving device for optical pickup device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving device incorporated in an optical pickup device for reproducing a disk such as a CD or a DVD. More specifically, the present invention relates to a detecting means for detecting which objective lens has been switched to an operating position in an objective lens driving device of a type in which an objective lens is switched according to a disk to be reproduced.

[0002]

2. Description of the Related Art As an objective lens driving device in an optical pickup device capable of reproducing different disks such as CDs and DVDs, there is known an objective lens driving device in which a plurality of objective lenses are switched and used in accordance with a disk to be reproduced. I have.

FIG. 3 shows an objective lens for a CD and a DVD.
FIG. 1 shows a partial cross section of an objective lens driving device called an axis sliding rotation system having an objective lens. As shown in this figure, an objective lens driving device 100 includes a lens holder 102 holding a CD objective lens 101 and a DVD objective lens (not shown), an axially movable lens holder 102, And a holder support unit 105 provided with a sliding shaft 104 rotatably supported on the shaft. Lens holder 102 and holder support unit 10
Between 5, a magnetic driving circuit for focusing and a magnetic driving circuit for tracking (both not shown) are formed.

[0004] On the upper surface 102a of the lens holder 102,
The objective lens 101 for CD and the objective lens for DVD are held at an angular interval of, for example, 90 degrees around the shaft hole 102b into which the sliding shaft 104 is inserted. The objective lens is switched by using the tracking magnetic drive circuit to rotate the lens holder 102 and position one objective lens at the operating position on the optical path of the laser light as shown in the figure.

[0005] After switching the objective lens, the magnetic drive circuit for focusing is driven to slide the lens holder 102 in the axial direction of the sliding shaft 104 so that the objective lens held by the lens holder 102 is moved. Focusing can be performed. Further, by driving the magnetic drive circuit for tracking, the lens holder 102 is rotated around the axis of the sliding shaft 104, and the lens holder 1 is rotated.
The tracking of the objective lens held at 02 can be performed.

[0006] The objective lens driving device 100 having this configuration is as follows.
A holder support unit 105 that supports the lens holder 102 is attached and fixed to an attachment frame 110 on the side of the optical pickup device main body. Then, the laser light L from the laser light source on the optical pickup device body side
Is guided to an objective lens (CD objective lens 101 in the figure) held in a lens holder 102 of an objective lens driving device 100 via an optical pickup optical system including a total reflection mirror 111, a collimator lens 112, and the like. Then, the light is condensed on the disk recording surface to be reproduced via an objective lens.

Here, the objective lens driving device 100 that uses two objective lenses by switching between them has a detection mechanism 120 for detecting which objective lens is used.

The detecting mechanism 120 includes an optical detecting mechanism 121 having a light reflecting surface 121 capable of reflecting a part of the laser light and a light receiving element 122 capable of receiving the laser light reflected by the light reflecting surface 121. It is. The light reflecting surface 121 is formed on the side surface of the lens holder 102 directly below the CD objective lens 101, and the light receiving element 122 is mounted on the frame 110 side. In a state where the CD objective lens 101 is used, a part of the laser light incident thereon is reflected by the light reflecting surface 121 and the holder supporting unit 1
The light-receiving element 122 is irradiated through an opening 107 formed in an outer peripheral wall 106 of the light-receiving element 05.

However, since no light reflecting surface is formed immediately below the mounting position of the DVD objective lens, the DV
When the D objective lens is used, reflected light is not detected by the light receiving element 122. Therefore, the used objective lens can be detected based on whether the light receiving element receives the laser beam.

[0010]

However, the detection mechanism having the above configuration has the following problems to be solved.

That is, the holder support unit 1 supporting the lens holder 102 on which the light reflecting surface 121 is formed.
Reference numeral 05 is attached and fixed to the frame 110 on the optical pickup device main body side. Therefore, when the mounting position or mounting angle of the holder supporting unit 105 with respect to the frame 110 changes, the light reflecting surface 121 on the lens holder 102 side and the light receiving element 122 on the frame 110 side
Changes with respect to the light receiving surface.

For example, in order to correct an aberration caused by a processing error or the like of the objective lens, the laser optical axis L0 of the objective lens is corrected.
It is necessary to fine-tune the angle with respect to. Since only the objective lens cannot be tilted with respect to the optical axis L0, the mounting angle of the holder support unit 105 supporting the lens holder 102 holding the objective lens with respect to the frame 110 is finely adjusted.

As described above, when the mounting angle of the holder support unit 105 to the frame 110 is finely adjusted, the light reflecting surface 121 and the light receiving element 12 constituting the light detecting mechanism are adjusted.
The relative position of 2 slightly shifts. That is, when the inclination angle of the reflection surface 121 changes in the up-down direction with respect to the reflected light L2 in the case of an appropriate relative positional relationship, the direction of the reflected light moves up and down as indicated by L21 and L22. When the direction of the reflected light changes, the light receiving element 1 at a fixed position
The amount of light received at 22 decreases. If the change in the inclination angle of the reflection surface 121 is large, the decrease in the amount of reflected light received is also large,
There is a possibility that switching of the objective lens cannot be detected based on the amount of light received by the light receiving element.

An object of the present invention is to always accurately detect switching of an objective lens even if the mounting angle of a holder support unit that supports a lens holder is finely adjusted for correcting aberrations of the objective lens. An object of the present invention is to propose an objective lens driving device of an optical pickup device having a detection mechanism.

[0015]

SUMMARY OF THE INVENTION The present invention comprises a lens holder holding a plurality of objective lenses, and a sliding shaft supporting the lens holder so as to be movable in the axial direction and rotatable about the axis. An optical pickup device having a holder support unit and a detection mechanism for detecting which of the plurality of objective lenses is in the operating position, wherein the support unit is fixed to a mounting frame on the optical pickup device main body side; In the objective lens driving device, the detection mechanism is configured to detect a position between a position where the light from the light source can be reflected and a position where the light from the light source cannot be reflected according to a rotation angle position of the lens holder accompanying the switching of the objective lens. And a light reflecting surface formed on the lens holder, and the holder supporting unit for receiving the reflected light reflected on the light reflecting surface. It is characterized in that a mounted light receiving portion.

In the objective lens driving device according to the present invention, since the light receiving portion, which is a component of the detecting means, is attached to the holder support unit, the attachment position or the attachment angle of the holder support unit with respect to the frame on the optical pickup device body side. Does not change the relative positional relationship between the light reflecting surface and the light receiving unit. Therefore, the light receiving amount required for detection can always be obtained in the light receiving unit, and thus, the switching detection of the objective lens can always be correctly performed based on the light receiving amount of the light receiving unit.

Further, at the stage when the lens holder is assembled to the holder supporting unit, the inspection of the detecting means can be performed. Therefore, unlike the conventional case, the inspection of the detecting means can be performed only after the holder support unit is attached and fixed to the frame on the optical pickup device main body side. There is also an advantage that a defect or the like of the detection means can be found on the side.

Furthermore, the holder supporting unit of the objective lens driving device is generally configured such that the internal space in which the lens holder is supported is substantially shielded and external light cannot enter. Therefore, if the light receiving unit is attached to the holder supporting unit having such a configuration, there is a small possibility that external light enters the light receiving unit, so that there is an advantage that erroneous detection can be reliably avoided.

Here, as the light source of the detecting means, a dedicated light source attached to the holder support unit can be employed. Alternatively, a laser light source on the optical pickup device main body side can be used as the light source of the detection means. In this case, a light reflecting surface may be formed on the lens holder so that a part of the laser light guided from the laser light source to one of the objective lenses can be reflected by the light reflecting surface.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an optical pickup apparatus according to the present invention; Since the entire structure of the objective lens driving device are identical to those of the axial sliding rotating type described above, the same reference numerals are given to corresponding portions, and their explanation is omitted.

(Overall Configuration) As shown in FIGS. 1A and 1B, an objective lens driving device 1 of a shaft sliding and rotating type equipped with a CD objective lens and a DVD objective lens has a CD objective lens. A lens holder 102 holding a lens 101 and a DVD objective lens 103;
And a holder support unit 105 provided with a sliding shaft 104 that supports the shaft in a direction axially and rotatable about the axis. A magnetic driving circuit for focusing and a magnetic driving circuit for tracking (both not shown) are formed between the lens holder 102 and the holder support unit 105.

On the upper surface 102a of the lens holder 102,
The objective lens 101 for CD and the objective lens 103 for DVD are held at an angular interval of, for example, 90 degrees around the shaft hole 102b into which the sliding shaft 104 is inserted. Using the tracking magnetic drive circuit, the lens holder 102
Is rotated to position one objective lens at an operating position on the optical path of the laser light as shown in the figure, thereby switching the objective lens. During the reproducing operation, the objective lens held by the lens holder 102 is focused by driving the focusing magnetic drive circuit to slide the lens holder 102 in the axial direction of the sliding shaft 104. Further, the magnetic drive circuit for tracking is driven to move the lens holder 102 to the sliding shaft 104.
, The tracking of the objective lens held by the lens holder 102 is performed.

In the objective lens driving device 1 of the present embodiment,
A holder support unit 105 that supports the lens holder 102 is attached and fixed to an attachment frame 110 on the side of the optical pickup device main body via an attachment angle (tilt) adjustment screw or the like.

A laser beam L from a laser light source on the optical pickup device main body side passes through an optical pickup optical system including a total reflection mirror 111, a collimator lens 112 and the like, and is transferred to a lens holder 102 of the objective lens driving device 1. Of the held objective lenses 101 and 103, the objective lens 101 is guided to the objective lens held at the operating position, and is condensed on the disk recording surface to be reproduced via the objective lens.

(Detection Mechanism of Objective Lens) A detection mechanism 20 for detecting which one of the two objective lenses 101 and 103 is used can reflect a part of the laser beam. The light reflecting surface 21 and the light reflecting surface 21
And a light receiving element 22 capable of receiving the laser beam reflected by the light source. As shown in FIG. 1B, the light reflecting surface 121 is formed on a part of a side surface 102c that defines a laser light passage path formed in the lens holder 102 immediately below the CD objective lens 101. On the other hand, the light receiving element 22 is attached to the peripheral wall 105a of the holder support unit 105. That is, the light receiving element 22 is mounted so as to block the outside of the opening 105c opened in the peripheral wall portion irradiated with the laser beam L20 reflected by the light reflecting surface 121. The light receiving surface 22a of the light receiving element 22 faces the light reflecting surface 21 via the opening 105c.

Therefore, when the laser light L is guided to the objective lens 101, a part of the light hits the light reflecting surface 21, where it is reflected almost at right angle toward the light receiving element 22, and the light receiving surface of the light receiving element 22 Irradiate 22a. In this way, while the CD objective lens 101 is used, a detection signal indicating that reflected light is received from the light receiving element 22 is obtained.

On the other hand, such a light reflecting surface is not formed immediately below the DVD objective lens 103 in the lens holder 102. That is, when the lens holder 102 is rotated 90 degrees in the direction of the arrow from the state where the CD objective lens 101 is in the operating position as shown in FIG. 1A, the DVD objective lens 103 is switched to the operating position.

FIG. 2 is a sectional view when the DVD objective lens 103 is in the operating position. As can be seen from this figure, the lens holder 1 immediately below the DVD objective lens 103
No light reflection surface is formed in the portion of No. 02. Therefore,
When the DVD objective lens 103 is in the operating position,
The light receiving element 22 attached to the peripheral wall 105a of the lens holding unit 105 does not receive the reflected light. Therefore, it is possible to detect which objective lens is being used based on whether or not the light receiving element 22 has received light.

As described above, in the objective lens driving device 1 of the present embodiment, the light receiving element 22 constituting the detection mechanism for detecting the used objective lens is attached to the holder support unit 105. is there. Therefore, for example, even if the inclination of the objective lens with respect to the optical axis is adjusted in order to correct the aberration of the objective lens, the detection mechanism 20 can be adjusted.
There is no change in the relative positional relationship between the light reflecting surface 21 and the light receiving element 22 constituting.

For example, the holder supporting unit 105 is attached and fixed to the frame 110 via a ball seat, and by adjusting a tilt adjusting screw, the tilt angle of the holder supporting unit 105 with respect to the frame 110 is adjusted with the ball seat as a fulcrum. It is possible. When the tilt adjusting screw is adjusted to correct the aberration of the objective lens, the tilt angle of the holder support unit 105 with respect to the frame 110 changes. Therefore, the objective lenses 101 and 10 held by the lens holder 102 supported by the holder support unit 105
Since the inclination angle of 3 also changes, aberration correction is performed. Even when the tilt angle of the holder support unit 105 is adjusted, the relative positional relationship between the light reflecting surface 21 and the light receiving element 22 constituting the detection mechanism 20 does not change. As a result, the reflected light reflected by the light reflecting surface 21 always accurately irradiates the light receiving surface 22a of the light receiving element 22, so that the light receiving is performed even though the objective lens used is the CD objective lens 101. There is no problem that the amount is insufficient and erroneous detection is performed.

Generally, the holder support unit 10
The opening side of 5 is closed so as to leave the rotational drive range of the objective lenses 101 and 103, and is configured so that dust and the like do not enter inside. Therefore, the peripheral wall 1 of the holder support unit 105
External light can be reliably prevented from entering the light receiving surface 22a of the light receiving element 22 attached to the light receiving element 05c.

Further, in the case where the components of the detection mechanism 20 are mounted only on the objective lens driving device 1 side as in this embodiment, the lens holder 102 is mounted on the holder support unit 105 at the stage of mounting. The inspection of the detection mechanism 20 can be performed. Therefore, unlike the conventional case, the inspection of the detecting means can be performed only after the holder support unit 105 is attached and fixed to the frame 110 on the optical pickup device main body side. There is also an advantage that a defect or the like of the detection mechanism 20 can be found on the upstream side of.

(Other Embodiments) In the above example, a part of the laser light for the optical pickup that is incident on the objective lenses 101 and 103 is used as the detection light source of the detection mechanism 20. Alternatively, a light source dedicated to the detection mechanism may be attached to the holder support unit. For example, in the above example, the holder support unit 1
Instead of the light- receiving element mounted on the light-receiving element 05, a photosensor having a light-emitting element and a light-receiving element may be mounted.

[0034]

As described above, the objective lens driving device of the optical pickup device according to the present invention includes the light receiving section of the detecting means for detecting which of the plurality of objective lenses is used. A configuration is adopted in which it is mounted on the holder support unit side. Therefore, even if the mounting position or the mounting angle of the holder support unit with respect to the frame on the optical pickup device main body side is adjusted for the purpose of correcting the aberration of the objective lens, the relative position of the light reflecting surface and the light receiving unit constituting the detecting means is not affected. There is no change in the positional relationship. Therefore, there is no adverse effect such that the light reflected by the light reflecting surface does not correctly irradiate the light receiving unit, so that the detection operation can always be performed accurately.

[Brief description of the drawings]

FIGS. 1A and 1B are a plan view and a sectional view of an objective lens driving device of an optical pickup device to which the present invention is applied.

FIG. 2 is a cross-sectional view showing a state where a DVD objective lens is switched to an operation position in the objective lens driving device of FIG.

FIG. 3 is a partial cross-sectional view mainly showing a detection mechanism for detecting which objective lens is being used in a conventional objective lens driving device.

DESCRIPTION OF SYMBOLS 1, 100 Objective lens driving device 101 Objective lens for CD 102 Lens holder 103 Objective lens for DVD 104 Sliding axis 105 Holder support unit 20 Detection mechanism 21 Light reflection surface 22 Light receiving element 22a Light receiving surface 110 Optical pickup device Frame on main body side Laser light L2, L20, L21, L22 Reflected light

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-221779 (JP, A) JP-A-2-260244 (JP, A) JP-A 8-138265 (JP, A) JP-A 9-208 161289 (JP, A) JP-A-9-288835 (JP, A) JP-A-4-31416 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 7/09-7 /twenty two

Claims (3)

(57) [Claims] A lens holder holding a plurality of objective lenses; a holder support unit including a slide shaft supporting the lens holder so as to be movable in an axial direction and rotatable around the axis; A detection mechanism for detecting which of the objective lenses is in the operating position, wherein the support unit is fixed to a mounting frame on the side of the optical pickup device main body. The mechanism moves the lens between a position where light from the light source can be reflected and a position where the light from the light source cannot be reflected, in accordance with a rotation angle position of the light source and the lens holder accompanying switching of the objective lens. A light-reflecting surface formed on the holder, and a light-receiving unit attached to the holder support unit for receiving reflected light reflected on the light-reflecting surface; An objective lens driving apparatus for an optical pickup device characterized in that it comprises. 2. An objective lens driving device for an optical pickup device according to claim 1, wherein said light source is mounted on said holder support unit. 3. The light source according to claim 1, wherein the light source is a laser light source on the optical pickup device main body side, and a part of the laser light guided from the laser light source to one of the objective lenses is the light reflecting surface. An objective lens driving device for an optical pickup device, characterized in that the objective lens driving device is capable of reflecting light.