JPH0684179A - Optical recording/reproduction device - Google Patents

Abstract

PURPOSE:To adjust skew accurately after adjusting the position of the visual field direction of an objective lens and that of the vertical direction to the visual field in an optical recording/reproduction device. CONSTITUTION:A support member 11 where a drive unit 12 where an objective lens 6 is supported so that it can be rocked is mounted to an upper surface is connected to a base member 19 via a spherical surface shaft part 20 and a spherical surface bearing part 21 so that the inclination can be adjusted and the spherical surface center of the spherical surface bearing part 21 is laid out at a main plane center 6a of the objective lens 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing apparatus for recording / reproducing information on / from a disc by a light beam.

[0002]

2. Description of the Related Art An optical recording / reproducing apparatus for recording / reproducing information on / from a disc-shaped recording medium is equipped with an optical pickup which constitutes an optical system for reading information from recording tracks formed on the disc recording medium. There is.

In such an optical pickup, for example, as shown in a simplified form in FIG. 5, the entire device including a semiconductor laser 1 and a photodetector 2 is integrally formed as one unit, and a disc D It is possible to move along the radial direction of. Then, the laser light beam emitted from the semiconductor laser 1 is diffracted by the grating 3 into three laser light beams (in FIG. 5, these three laser light beams are shown by one line for simplification. The polarization beam splitter 4 changes its optical axis direction and makes it enter the collimator lens 5. Then, the laser light beam that is collimated by the collimator lens 5 is made incident on the disc D through the objective lens 6, is modulated in the recording track formed on the disc D, and is reflected.

The reflected laser light beam from the disk D is
The light passes through the objective lens 6 and the collimator lens 5 one after another, returns through the polarization beam splitter 4 without changing its optical axis direction, and is guided to the photodetector 2 through the light receiving lens (concave lens) 7. Then, the detection output obtained from the photodetector 2 is supplied to a signal processing unit (not shown) to form a reproduction information signal, a focus control signal and a tracking control signal. Each of them is supplied to a focus control drive unit 8 and a tracking control drive unit 9 arranged in association with the objective lens 6, whereby the objective lens 6 is moved toward or away from the disc D along its optical axis. A driving operation for focus control is performed to move the objective lens 6 as much as possible, and a driving operation for tracking control is performed to move the objective lens 6 in the radial direction of the disc D which is a direction orthogonal to the optical axis of the objective lens 6. .

In the optical pickup having the objective lens 6 configured as described above, the semiconductor laser 1 emits a high-power laser beam. Then, in order to guarantee the emission power of the semiconductor laser 1 in the recording / erasing mode at the time of access within the field of view peculiar to the optical pickup, the objective lens 6 and the parallel beam incident on the objective lens 6 are assembled when the optical pickup is assembled. The positional relationship of is adjusted. That is, the optical pickup used for recording / erasing such as WO / MO has the maximum emission power in the visual field direction, and therefore the mechanical position is adjusted only in the direction perpendicular to the visual field. Also CD
In an optical pickup used for VD or the like, the mechanical positions of the objective lens 6 and the collimator lens 5 are adjusted in both the visual field direction and the direction perpendicular to the visual field. After the above position adjustment, the tilt of the objective lens 6 with respect to the visual field direction is adjusted,
Guarantees coma.

[0006]

In the conventional optical recording / reproducing apparatus as shown in FIG. 5, the incident beam on the objective lens 6 is constructed within the mechanical precision of the mechanical component having rigidity. , Relatively easy to manage. However, since the objective lens 6 is supported by a suspension composed of a metal leaf spring or a rubber elastic body via a bobbin member, the positional relationship accuracy with respect to other elements cannot be guaranteed. Therefore, the position adjustment as described above is required in the assembly process of the optical pickup.

The above-described adjustment of the coma aberration has heretofore been performed by rotating the objective lens 6 around its principal plane position. However, in the case of WO / MO and the like, since the parameters guaranteed in the field of view are different, there is a problem that the adjustment fluctuates when the objective lens 6 is rotated around the main plane position.

The present invention has been made in view of such circumstances, and optical recording / reproducing is possible in which the skew adjustment can be accurately performed after the position adjustment of the objective lens in the visual field direction and the direction perpendicular to the visual field. The purpose is to provide a device.

[0009]

An optical recording / reproducing apparatus according to a first aspect of the present invention includes a drive unit 12 as a drive member for swingably supporting an objective lens 6, and a drive unit 1 on the upper surface.
2, a support member 11 having a spherical shaft portion 20 on its lower surface, and a spherical bearing portion 21 with which the spherical shaft portion 20 engages are provided, and a base member 19 for connecting the support member 11 so that the inclination thereof can be adjusted. In the optical recording / reproducing apparatus, the center of the spherical surface is located at the main plane center 6a of the objective lens 6.

An optical recording / reproducing apparatus according to a second aspect of the present invention is characterized in that the center of the spherical surface is arranged at the aperture center 6b of the objective lens 6.

[0011]

In the optical recording / reproducing apparatus having the above structure, the position of the center of rotation in the visual field direction during the radial skew rotation adjustment is
By setting the position of the main plane of the objective lens 5 or the center of each of the apertures, even if the skew adjustment is performed after the lens position adjustment, the efficiency that affects the output power of the parallel beam by the lens does not change. As a result, the adjustment parameters are guaranteed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optical recording / reproducing apparatus of the present invention will be described below with reference to the drawings.

FIG. 4 shows an example of the structure of an optical pickup to which this embodiment is applied. In FIG. 4, the drive unit 12 is screwed to the upper surface side of the support member 11. A bobbin 15 to which the objective lens 6 is fixed is attached to the drive unit 12 via a pair of suspensions 14, one end of which is fixed to a mounting portion 13, so that the bobbin 15 can swing vertically and horizontally. A focus control coil 16 and a tracking control coil 17 are attached to both sides of the bobbin 15, and a pair of left and right magnets (not shown) is fixed to the support member 11 so as to face the coils 16 and 17. . The winding directions of the coils 16 and 17 are orthogonal to each other. When the focus control signal is supplied to the focus control coil 16, the objective lens 5 moves in the optical axis direction and the tracking control signal is supplied to the tracking control coil 17. Then, the objective lens 5 moves in a direction orthogonal to the optical axis.

The support member 11 is attached to the movable base member 19 via three screws 18, and the support member 11
A spherical shaft portion 20 is provided on the lower surface side of the. Further, a spherical bearing portion 21 which is in sliding contact with the spherical shaft portion 20 is provided on the upper surface side of the movable base member 19, and the support member 11 is slidably engaged with the spherical shaft portion 20. It is superposed on the movable base member 19.

One screw 1 of the above three screws 18
The head of 8a projects from the lower surface of the movable base member 19, and a coil spring 22 is mounted between the head of the screw 18a and the lower surface of the movable base member.
The support member 11 is urged to move to the movable base member 19 side via. The other two screws 18b
(One of them is not shown) is screwed into the support member 11,
Alternatively, by screwing back, the support member 11 rotates on the spherical bearing portion 21, and the tilt angle of the objective lens 5 is adjusted. Here, as shown in FIG. 1, the center of the spherical bearing portion 21 is located at the center 6a of the main plane of the objective lens 6.

Next, the operation of this embodiment will be described. WO ・ M
In the optical pickup used in the recording / erasing mode such as O, the efficiency of the light intensity emitted from the objective lens 6 is important. As shown in FIG. 2, the beam 31 incident on the objective lens 6 has a position-dependent intensity distribution. In the optical pickup, it is required to guarantee the characteristics in a moving state of about ± 0.5 mm in the tracking direction, which is called a visual field access. The intensity distribution in the radial direction shown in FIG. 2 causes a change in the efficiency of light intensity depending on the visual field position of the objective lens 6. In this case, there is a problem in guaranteeing the optical power in the recording / erasing mode. Therefore, adjustment is performed so that the center of the objective lens and the center of the light intensity coincide with each other as the position where the power fluctuation is smallest when the visual field is accessed.

According to the configuration of this embodiment shown in FIG. 1, after adjusting the position of the objective lens 6 in the visual field direction and in the direction perpendicular to the visual field direction, when adjusting the inclination of the objective lens 6 with the screw 18b, the objective lens 6 is adjusted. Main plane center 6 of lens 6
Since the rotation is performed around a, the position in the perpendicular direction does not change. Therefore, the efficiency of light intensity does not change and the adjustment parameter is guaranteed.

As shown in FIG. 3, the center of the spherical bearing portion 21 may be arranged at the aperture center 6b of the objective lens 6, and substantially the same effect can be obtained. In this case, the objective lens 6
The position of the beam in the direction perpendicular to the incident beam causes a slight error but is within the allowable range.

[0019]

As described above, according to the optical recording / reproducing apparatus of the present invention, the position in the visual field direction of the rotation center during the radial skew rotation adjustment is the center of the main plane of the objective lens or the center of the aperture. Even if the skew is adjusted after the lens position adjustment, the influence of the output power of the parallel beam by the lens does not change, and the adjustment parameter is guaranteed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a positional relationship between a spherical bearing and an objective lens according to an embodiment of an optical recording / reproducing apparatus of the present invention.

FIG. 2 is an explanatory view showing the operation of one embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a positional relationship between a spherical bearing and an objective lens according to another embodiment of the present invention.

FIG. 4 is a partial cross-sectional side view showing the configuration of an example of an optical pickup to which an embodiment of the present invention is applied.

FIG. 5 is a configuration diagram showing an optical system of an example of a conventional optical recording / reproducing apparatus.

[Explanation of symbols]

 6 Objective Lens 6a Main Plane Center 6b Aperture Center 11 Support Member 12 Drive Unit (Drive Member) 19 Base Member 20 Spherical Shaft Part 21 Spherical Bearing Part

Claims (2)

[Claims] 1. A drive member for swingably supporting an objective lens, a support member having an upper surface to which the drive member is attached and a lower surface having a spherical shaft portion, and a spherical bearing portion with which the spherical shaft portion is engaged. An optical recording / reproducing device provided with a base member for connecting the supporting member so that the tilt angle can be adjusted, wherein the center of the spherical surface is arranged at the center of the main plane of the objective lens. . 2. The optical recording / reproducing apparatus according to claim 1, wherein the center of the spherical surface is arranged at the center of the aperture of the objective lens.