JP2001160230A - Optical head device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical head device having a use lens detecting mechanism capable of always well maintaining use lens detecting sensitivity without being affected by a mounting posture. SOLUTION: The optical head device 1 has the use lens detecting mechanism 20 for detecting which of objective lenses 101 and 103 exists in an operating position. The use lens detecting mechanism 20 has a light reflection surface 21 formed at a lens holder 102 in order to reflect part of a laser beam while the objective lens 103 is used and a photodetector 22 mounted at a holder supporting unit 105 in order to receive the reflected light reflected by the light reflection surface 21. The major axis direction MJ of an FFP of the laser beam L aligns to a direction where the light reflection surface 21 is installed. Then, even if the light reflection surface 21 formed at the lens holder 10 is moved by the mounting posture, the photodetector 22 may be always irradiated with the reflected laser beam L21 of a sufficient light quantity and therefore the use lens detection is eventually executed with the always good detection sensitivity without being affected by the mounting posture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical head device for performing recording and reproducing operations on disks such as CDs and DVDs. More specifically, the present invention relates to an improvement in a used lens detecting mechanism for detecting which objective lens is switched to an operating position in an optical head device of a type in which an objective lens is switched according to a disc to be reproduced. is there.

[0002]

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

FIG. 6 shows a CD objective lens and a DVD.
1 shows a partial cross section of an objective lens driving mechanism called an axial sliding rotation method in an optical head device provided with an objective lens for use. As shown in this figure, an objective lens driving mechanism 100 includes a lens holder 102 holding a CD objective lens 101 and a DVD objective lens (not shown).
And a holder support unit 105 having a sliding shaft 104 that supports the lens holder 102 so as to be movable in the axial direction and rotatable around 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.

[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.

A holder support unit 105 for supporting the lens holder 102 is fixedly mounted on a mounting frame 110 on the side of the optical head device main body. The laser light L from the laser light source on the optical head 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 mechanism 100 for switching and using two objective lenses is provided with a used lens detecting mechanism 120 for detecting which objective lens is used. I have.

The used lens detecting mechanism 120 includes a light reflecting surface 121 capable of reflecting a part of the laser light,
An optical detection mechanism including a light receiving element 122 capable of receiving the laser light reflected by the light receiving element 122. The light reflecting surface 121 is a CD
Lens holder 102 directly below the objective lens 101 for use
The light receiving element 122 is attached to the frame 110 side. In a state in which the CD objective lens 101 is used, a part of the laser light incident thereon is reflected by the light reflecting surface 121,
The light receiving element 122 is irradiated through an opening 107 formed in the outer peripheral wall 106 of the holder support unit 105.

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.

Here, the used lens detecting mechanism of this configuration has the following problems. That is, the holder support unit 105 that supports the lens holder 102 on which the light reflecting surface 121 is formed is the frame 1 on the optical head device main body side.
10 and fixed. Therefore, frame 11
When the mounting position or mounting angle of the holder support unit 105 with respect to the lens holder 102 changes, the lens holder 102
Side light-reflecting surface 121 and frame 110 side light-receiving element 1
The relative position of the light receiving surface 22 to the light receiving surface changes.

For example, in order to correct an aberration caused by a processing error or the like of the objective lens, a laser optical axis L0 of the objective lens is used.
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.

If the mounting angle of the holder support unit 105 to the frame 110 is finely adjusted in this manner, the relative positions of the light reflecting surface 121 and the light receiving element 122 constituting the used lens detecting mechanism slightly shift. That is, when the inclination angle of the reflecting surface 121 changes in the vertical direction with respect to the reflected light L2 in the case where the relative positional relationship is appropriate,
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 amount of light received by the light receiving element 122 at the fixed position 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 large, and it may be impossible to detect the switching of the objective lens based on the amount of light received by the light receiving element.

Therefore, one of the present applicants first described in
Japanese Patent Application Publication No. 154337 proposes a configuration in which the light receiving element 122 is attached to the holder support unit 105. According to this configuration, even if the mounting angle of the holder support unit 105 with respect to the frame 110 changes, the light reflecting surface 121 and the light receiving element 1 constituting the lens detection mechanism to be used.
22 does not change, the light reflecting surface 1
The amount of movement of the light reflected by 21 on light receiving element 122 is small. Therefore, even if the mounting angle of the holder supporting unit supporting the lens holder is finely adjusted for correcting the aberration of the objective lens, the switching of the objective lens can always be detected accurately.

[0014]

However, there is a point to be further improved in such a used lens detecting mechanism. That is, since the lens holder is slidable along the sliding axis, the direction of gravity acting on the lens holder differs depending on the mounting posture of the optical head device with respect to a CD / DVD reproducing device or the like. For this reason, for example, when the optical head device is mounted so that the sliding axis is horizontal, and when the optical head device is mounted so that the sliding axis is vertical, the lens holder is The amount of falling under its own weight along the distance is substantially zero in the former case, but becomes a non-negligible amount in the latter case.

As a result, the position of the light reflecting surface for detecting the used lens formed on the lens holder changes relative to the light receiving element. In particular, since the far field pattern of the laser beam is elliptical, for example,
When the light reflecting surface is positioned in the short axis direction of the ellipse, etc., the light reflecting surface is not irradiated with a sufficient amount of laser light, and the light receiving surface is moved by the light reflecting surface to detect the lens. Therefore, there is a high possibility that the necessary amount of light cannot be received. When such a situation occurs, the detection sensitivity decreases, and accurate detection cannot be expected.

An object of the present invention is to propose an optical head device in which the detection sensitivity of a used lens detecting mechanism does not vary depending on the mounting posture.

[0017]

SUMMARY OF THE INVENTION The present invention provides a laser light source, a plurality of objective lenses for converging light emitted from the laser light source on an optical recording medium, a lens holder holding these objective lenses, A holder support unit having a sliding shaft that supports a lens holder so as to be movable in the axial direction and rotatable around the axis, and a used lens detection mechanism that detects which of the plurality of objective lenses is in the operating position In the optical head device having the above, the used lens detection mechanism is configured to be capable of reflecting a laser beam emitted from the laser light source and a non-reflective lens according to a rotation angle position of the lens holder accompanying the switching of the objective lens. A light-reflecting surface formed on the lens holder, and a light-receiving unit for receiving light reflected by the light-reflecting surface so as to move between different positions. Includes and is characterized by the wide direction of the far field pattern of the emitted laser beam is coincident with the moving direction of the lens holder along the sliding axis.

In a typical configuration, when the rotational position of the lens holder is a position capable of reflecting the emitted laser light, the light reflecting surface does not reflect the effective light beam of the objective lens,
This is a position where the peripheral light beam is reflected, and the wide direction of the far field pattern of the emitted laser light coincides with the direction in which the light reflecting surface exists.

Here, if the light reflecting surface is any one of a curved surface and a diffusing surface, the light reflected on the light reflecting surface can be guided to the light receiving portion as a divergent light flux. As a result,
Compared with the case where parallel light is guided to the light receiving unit, it is possible to suppress a change in detection sensitivity due to a change in the relative position between the light reflecting surface and the light receiving unit.

It is preferable that the light reflecting surface is disposed in a lens barrel for guiding the emitted laser light to the smallest diameter objective lens among the plurality of objective lenses. With this configuration, the light reflecting surface can be made closer to the center side of the laser output light beam, the effective area of the light reflecting surface can be increased, and more reflected light amount can be provided for the peripheral light amount attenuation of the laser output light. Obtainable. Therefore, even if the light reflecting surface moves, the light reflecting surface can be prevented from deviating from the emitted laser beam.

Further, in the present invention, it is desirable that the light receiving section is attached to the holder supporting unit.

If the area of the light receiving portion of the light receiving element is smaller than the cross-sectional area of the light reflected by the light reflecting surface, the light receiving surface is located at a position where the light reflecting surface does not reflect the laser output light. It becomes difficult for stray light to enter the element, and erroneous detection due to an increase in unnecessary light reception amount can be suppressed.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical head device for reproducing a CD / DVD to which the present invention is applied will be described below with reference to the drawings. Since the overall configuration of the objective lens driving mechanism is the same as that of the above-described shaft sliding / rotating type (see FIG. 3), corresponding portions are denoted by the same reference numerals and description thereof is omitted.

As shown in FIGS. 1 and 2, the objective lens driving mechanism 2 of the optical head device 1 of this embodiment is also of an axial sliding rotation type, and the objective lens 101 for CD and the objective lens 103 for DVD are used. The apparatus includes a held lens holder 102 and a holder support unit 105 having a sliding shaft 104 that supports the lens holder 102 so as to be movable in the axial direction and rotatable around the axis. Lens holder 102
A magnetic driving circuit for focusing and a magnetic driving circuit for tracking (both are not shown) are formed between the magnetic disk drive 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 L as shown in the figure,
Switching of the objective lens is performed. 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 tracking magnetic drive circuit is driven to move the lens holder 102 to the sliding shaft 10.
The objective lens held by the lens holder 102 is tracked while being rotated about the axis 4.

Also in the optical head device 1 of this embodiment, a holder support unit 105 that supports the lens holder 102
Is attached and fixed to an attachment frame (head base) 110 on the side of the optical head device main body via an attachment angle (tilt) adjustment screw or the like.

The laser light source 4 on the optical head device body side
Out of the objective lenses 101 and 103 held in the lens holder 102 of the objective lens driving device 1 via the optical pickup optical system including the collimator lens 112, the rising mirror 111, and the like. Is guided to the objective lens on the side held at the position, and through the objective lens, the disk CD or DVD to be reproduced
Is focused on the recording surface of.

A used lens detecting mechanism 20 for detecting which one of the two objective lenses 101 and 103 is used includes a light reflecting surface 21 capable of reflecting a part of the laser light, The optical type is provided with a light receiving element 22 capable of receiving the laser light reflected by the light reflecting surface 21.

As shown in FIG. 2, the light reflecting surface 21 is an end surface of a lens barrel 23 that defines a laser beam passage formed in a lens holder 102 immediately below a small-diameter objective lens, in this example, a DVD objective lens 103. Of the laser light, and is inclined at 45 degrees to the optical axis of the laser light.

On the other hand, the light receiving element 22 includes a cup-shaped yoke 24 which is a component of the holder support unit 105.
Is attached to the peripheral wall 24a. That is, the light receiving element 22 is mounted at a height position facing the light reflecting surface 21 from outside the opening 24b opened in the yoke peripheral wall portion irradiated with the laser light L21 reflected by the light reflecting surface 21.

Therefore, when the laser light L is guided to the objective lens 103, 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, where the light receiving surface of the light receiving element 22 is received. Irradiate 22a. In this manner, while the DVD objective lens 103 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 CD objective lens 101 in the lens holder 102. That is, from the state where the DVD objective lens 103 is in the operating position as shown in FIG.
When the lens holder 102 is rotated by 90 degrees, the CD objective lens 101 is switched to the operating position, and the state shown in FIG. 3 is obtained.

FIG. 3 is a sectional view when the CD objective lens 101 is in the operating position. As you can see from this figure,
A light reflecting surface is not formed in a portion of the lens holder 102 directly below the CD objective lens 101. Therefore, when the CD objective lens 101 is in the operating position, the light receiving element 22 attached to the peripheral wall 24 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.

Here, in the optical head device 1 of the present embodiment, by adjusting the polarization direction of the laser light source 4, the far field pattern (hereinafter, FF) of the emitted laser light L is adjusted.
Called P. ) Is set so that the wide direction coincides with a certain direction of the light reflecting surface.

As described above, in the optical head device 1 of the present embodiment, when the mounting posture is changed, the lens holder 102 slidably supported along the axial direction 104a with respect to the sliding shaft 104 causes the gravitational force. Of the lens holder 102 changes accordingly.
The initial position at 04a also slightly fluctuates. As a result,
The light reflecting surface 21 of the used lens detecting mechanism 20 formed on the lens holder 102 also moves, and the relative position of the light receiving element 22 with respect to the light receiving surface changes.

However, in this example, as shown in FIG. 4A, the major axis direction MJ of the FFP of the laser light L is
Since the light reflecting surface 21 coincides with a certain direction, the light reflecting surface 21 can be sufficiently placed in the passage area of the laser light L. That is, D formed on the lens holder 102
Since the distance between the VD aperture stop 27 and the edge of the FFP can be widened, the laser light can be reflected over a wide width and guided to the light receiving element 22 side.

As a result, even if the light reflecting surface 21 moves up and down as indicated by the dashed line in FIG. 4A, the light amount required for performing an accurate detection operation on the light receiving element 22 is obtained. Laser reflected light can be guided. Therefore,
The use lens detection mechanism 20 can always accurately detect the use lens without being affected by the mounting posture of the optical head device 1.

On the other hand, as shown in FIG.
If the minor axis direction MI of the elliptical FFP of the laser light L coincides with a certain direction of the light reflecting surface 21, the light reflecting surface 21 cannot be sufficiently entered into the laser light passage area, and is reflected here. Laser light has a narrow width. For this reason, when the light reflecting surface 21 moves up and down, there is a high possibility that the reflected laser light deviates from the light receiving surface 22 a of the light receiving element 22. Therefore, there is a possibility that the amount of received light necessary to secure a predetermined detection sensitivity may not be obtained, and that there is a possibility that an accurate detection of the used lens cannot be performed. In this example, as described above, such an adverse effect does not occur.

In this embodiment, the light reflecting surface 21 of the used lens detecting mechanism 20 is disposed immediately below the small-diameter objective lens, that is, the DVD objective lens 103. Since the aperture stop of the small-diameter lens is small, the light reflecting surface 21 can be arranged at a position closer to the center side of the laser light. As a result, FIG.
Similarly to the case described with reference to the above, even if the mounting posture of the optical head device changes and the lens holder 104 moves, a sufficient amount of laser light can be received by the light reflecting surface 21 mounted thereon. 22 can be reflected.

Further, in this embodiment, the light receiving element 22 constituting a detection mechanism for detecting the used objective lens is attached to the holder support unit 105.
Therefore, for example, even if the tilt angle of the objective lens with respect to the optical axis is adjusted in order to correct the aberration of the objective lens, the light reflecting surface 21 and the light receiving element 22 constituting the detection mechanism 20 can be adjusted.
There is no change in the relative positional relationship of.

For example, the holder supporting unit 105 is attached and fixed to the frame 110 side 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 position where the light reflected by the light reflecting surface 21 is incident on the light receiving surface 22a of the light receiving element 22 fluctuates little, and the light is always accurately irradiated. No failures occur.

In general, 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 the present 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, as in the conventional case, the holder supporting unit 105 is moved to the frame 1 on the optical head device body side.
Unlike the case where the inspection of the detecting means can be performed only after the optical head device has been attached and fixed, there is an advantage that a defect or the like of the detecting mechanism 20 can be found on the upstream side of the manufacturing process of the optical head device. is there.

(Other Embodiments) In the above example, the light reflecting surface 21 of the detection mechanism 20 is a flat surface as shown in FIG. Instead, a light reflecting surface 21A having a concave curved surface as shown in FIG. 5B may be used. By doing so, the reflected laser light L2 reflected by the light reflecting surface 21A
1 can be applied to the light receiving surface 22a of the light receiving element 22 as diffused light. As a result, the width A of the reflected laser light on the light receiving surface 22a can be made wider than the reflection width a on the planar light reflecting surface 21, and the detection sensitivity caused by the change in the relative position between the light reflecting surface 21 and the light receiving surface 22a. Degradation can be suppressed.

Of course, a light reflecting surface having a convex curved surface may be employed instead of the concave curved surface. Alternatively, the reflected laser light can be used as diffused light by using a light reflecting surface having a diffusing surface as a reflecting surface.

[0046]

As described above, in the optical head device of the present invention, the wide direction of the far-field pattern of the emitted laser light is made to coincide with the direction of the light reflecting surface for detecting the lens to be used. Therefore, the light reflecting surface for detecting the used lens formed on the lens holder that slides along the sliding axis moves along the sliding axis, and the relative position with respect to the light receiving element for detecting the used lens fluctuates. However, the required amount of laser light can always be reflected to the light receiving element. Therefore,
Even if the position of the lens holder fluctuates due to the mounting posture of the optical head device, the used lens can be always detected with high detection sensitivity.

In the present invention, a light reflecting surface for detecting a lens to be used is disposed in a lens barrel for guiding a laser beam to a small-diameter objective lens. Even when this configuration is employed, even if the position of the lens holder on which the light reflecting surface is formed fluctuates along the sliding axis, the detection sensitivity of the used lens detection mechanism can be maintained satisfactorily.

Further, according to the present invention, by forming the light reflecting surface of the used lens detecting mechanism as a curved surface or a diffusing surface, it is possible to irradiate the light receiving element with diffused light having a width wider than the laser light reflection width on the light reflecting surface. Like that. If the width of the reflected laser beam for detecting the used lens is made wider in this manner, the detection sensitivity of the used lens detecting mechanism is reduced even if the relative position between the light reflecting surface formed on the lens holder and the light receiving element changes. Can be suppressed.

Further, in the present invention, the area of the light receiving portion of the light receiving element is made smaller than the sectional area of the light reflecting surface. Therefore, when the light reflecting surface is at a position where the emitted laser light is not reflected, stray light hardly enters the light receiving element, and erroneous detection due to an unnecessary increase in the amount of received light can be suppressed.

[Brief description of the drawings]

FIG. 1 is a partial perspective view showing a part of an objective lens driving mechanism in an optical head device to which the present invention is applied.

FIG. 2 is a cross-sectional configuration diagram showing a state when a DVD objective lens is used in the objective lens driving mechanism of FIG. 1;

FIG. 3 is a cross-sectional configuration diagram showing a state when a CD objective lens is used in the objective lens driving mechanism of FIG. 1;

FIG. 4 is an FF of laser light in the optical head device of FIG.
It is explanatory drawing which shows the relationship between P and the moving direction of the light reflection surface for use lens detection, and the effect by that.

FIG. 5 is an explanatory diagram for explaining a modification of the light reflection surface of the used lens detection mechanism in the optical head device of FIG. 1;

FIG. 6 is a partial sectional view mainly showing a detection mechanism for detecting which objective lens is being used in a conventional objective lens driving device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical head device 2 Object lens drive mechanism 101 Object lens for CD 102 Lens holder 102c Moving direction of lens holder (moving direction of light reflection surface) 103 Object lens for DVD 104 Sliding axis 104a Axis 105 Holder support unit 20 Detection of used lens Mechanism 21 Light reflecting surface 22 Light receiving element 22a Light receiving surface 110 Frame L side of optical head device main body L Laser light L21 Reflected light MJ Long axis direction of FFP of laser beam MI Short axis direction of FFP of laser beam

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[Procedure amendment]

[Submission date] December 15, 1999 (1999.12.
15)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

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FIG.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

[Procedure amendment 4]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

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[Procedure amendment 5]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Tohru Hotta 5329 Shimosuwa Town, Suwa County, Nagano Prefecture Inside Sankyo Seiki Seisakusho Co., Ltd. (72) Inventor Ikuo Kasuga 5329 Shimo Suwa Town, Suwa County, Nagano Prefecture Sankyo Seiki Seisakusho (72) Inventor Toshihiko Okina 5329 Shimosuwa Town, Suwa County, Nagano Prefecture Inside Sankyo Seiki Seisakusho Co., Ltd. (72) Inventor Akira Kinoshita 70 Yanagicho, Yuki-ku, Kawasaki City, Kanagawa Prefecture Toshibauchi Corporation (72) Inventor Hideo Kurosawa 70, Yanagicho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture (72) Inventor Hidenori Sai 70, Yanagimachi, Kawasaki-shi, Kanagawa Prefecture Toshibauchi, Inc. (72) Inventor Masayuki Shinoda 70, Yanagicho, Sakai-ku, Kawasaki City, Kanagawa Prefecture Shares Company Toshiba F-term (reference) 5D118 AA14 AA26 BA01 BB01 BB07 CD06 CF30 DC03 EA02 FA07 5D119 AA41 BA01 BB01 BB04 JA49 JA57 KA14 LB03 </ S> </ s> </ s>

Claims (6)

[Claims] 1. A laser light source, a plurality of objective lenses for converging light emitted from the laser light source on an optical recording medium, a lens holder holding these objective lenses, and the lens holder being movable in an axial direction. And an optical head device having a holder support unit having a sliding shaft rotatably supported about an axis, and a used lens detection mechanism for detecting which of the plurality of objective lenses is in the operating position. The used lens detection mechanism moves between a position where the laser beam emitted from the laser light source can be reflected and a position where the laser beam cannot be reflected according to the rotation angle position of the lens holder accompanying the switching of the objective lens. A light-reflecting surface formed on the lens holder; and a light-receiving unit for receiving light reflected by the light-reflecting surface. An optical head apparatus characterized by wide direction of the far field pattern of Heather light is coincident with the moving direction of the lens holder along the sliding axis. 2. The light reflecting surface according to claim 1, wherein when the rotation position of the lens holder is a position at which the emitted laser light can be reflected, the light reflecting surface does not reflect the effective light beam of the objective lens but reflects the peripheral light beam. An optical head device, wherein a position of the far-field pattern of the emitted laser light corresponds to a direction of the light reflecting surface. 3. The optical head device according to claim 1, wherein the light reflecting surface is any one of a curved surface and a diffusing surface. 4. The light reflecting surface according to claim 1, wherein the light reflecting surface is disposed in a lens barrel that guides the emitted laser light to the smallest diameter objective lens among the plurality of objective lenses. An optical head device comprising: 5. The optical head device according to claim 1, wherein the light receiving unit is attached to the holder support unit. 6. The optical head device according to claim 1, wherein an effective area of a light detecting section of the light receiving section is smaller than a sectional area of the light reflecting surface.