JPH0298828A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To control the shift quantity of a light beam to be small and to reduce the offset quantity of a position sensor by moving an objective lens is parallel with the aid of a piezoelectric element and adjusting the position of the light beam. CONSTITUTION:In the case that an optional track on an optical disk 8 is selected, the position of the track is roughly adjusted by driving a movable carriage 13 in the direction of an arrow A through a feed mechanism constituted of a permanent magnet and coils 19a and 19b. Next, parallel leaf springs 12a and 12b supporting the objective lens 9 through a lens holder 10 are finely moved in the direction of an arrow D by adjusting a voltage impressed on the laminating type piezoelectric element 15. Then, the position of the tracking direction of a light spot condensed on the optical disk 8 through the parallel movement of the objective lens 9 is finely adjusted. Thus, the change of the shift quantity of reflected light from an information medium caused by the control of the tracking is controlled to be small. Besides, the change of the shift quantity is made unconcerned with the position of the tracking.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical information recording and reproducing device, particularly when writing and reading information to and from an optical disk medium that optically records and reproduces information. The present invention relates to an optical information recording/reproducing device suitable for implementing tracking control with a simple configuration.

[Prior Art] FIG. 7 is a schematic diagram of a conventional optical information recording/reproducing device, particularly illustrating an optical disk device. In the figure, (1) is a space that serves as a base for configuring this optical information recording and reproducing device, and (2) is a space that is fixedly provided to this base (1) and is a light beam for recording or reproducing information. (3) A fixed optical system having a laser light source and optical system (not shown) for emitting the light, and a detector (not shown) for detecting the returning light beam for information reading and various controls;
(4) is the light beam (3) emitted from the fixed optical system (2)
The triangular prism (5) bends the optical path of the triangular prism (4) at right angles, and the arrow mark (5) rotates the reflecting mirror (6) around the axis (7) to adjust the exit angle of the light beam (3) reflected by the triangular prism (4). The galvanometer mirror control unit rotates in direction B to adjust the reflection angle of the light beam (3) from the triangular prism (4), and (8) is a concentric or spiral mirror for optically recording and reproducing information. A well-known optical disc (9) having an information track of the shape of the figure and being rotated by means not shown is fed onto the optical disc (8) via a galvano-mirror control bag fitlffl (5). An objective lens for condensing a light beam (3), (10) a lens holder that holds the objective lens (9), and (11) a permanent lens (not shown) that is wound around the lens-holder (10) and responds to the applied current. The focus coils (12a) and (12b), which drive the objective lens (9) in the focus adjustment direction, that is, in the direction of arrow C, by the electromagnetic force generated between them and the magnet, move in the direction of arrow A on the base (1). A parallel plate spring (14) movably supports a lens holder (]O) which has one end fixed to a freely disposed movable carriage (13) and holds an objective lens (9) at the other end in the focus adjustment direction. This is a triangular prism fixed to a movable carriage (13) to reflect the light beam (3) from the carbano mirror control unit (5) at right angles and guide it to the objective lens (9). Incidentally, the optical disc (8) is arranged so that its information tracks are lined up in the direction of arrow A.

The operation of this configuration will be explained next.

The light beam (3) emitted from the fixed optical system (2) passes through a triangular prism (4), a reflecting mirror (6) and a triangular prism (
14), enters the objective lens (9) along the optical axis of the objective lens (9), and is condensed onto the front disk (8) to form a light spot. The spot ahead is modulated when recording information on the optical disc (8) J:
information according to the modulation is recorded. On the other hand, when reproducing information, the reflected light from the optical disc (8) is modulated according to the information recorded on the optical disc (8), and this reflected light is transmitted from the objective lens (9) to the triangular prism (14), The light is reflected by the mirror (6) and the triangular prism (4), returns to the fixed optical system (2) in the opposite path, and is detected by a photodetector (not shown). Note that regardless of whether information is being read or written, the reflected light from the optical disk (8) is returned to the fixed optical system (2) and used for focus control and tracking control.

When selecting an arbitrary track on the optical disk (8), the movable carriage (13) is driven in the direction of the arrow through a feed mechanism (not shown) to roughly adjust the track position, and then the galvano mirror! IIa+device 1 (5)
, J: is the anti-J11 Mira (6) and the rotation axis (7)
Move the optical disc (8) slightly in the direction of arrow B around the center.
Finely adjust the position of the optical spot focused above in the tracking direction.

In addition, when adjusting the focus of the optical spot on the optical disk (8) by the objective lens (9), by energizing the focus coil (11), the parallel leaf spring (12a) is activated by interaction with a permanent magnet (not shown). (12b
), the movable carriage (1
3) is driven in the direction of arrow C, that is, in the optical axis direction of the objective lens (9), and the lens holder (10) supported by the lens holder (10) is driven in the focal direction of the objective lens (9) held by the lens holder (10). Adjusting the position.

[Problem to be solved by the invention J Since the conventional optical information recording/reproducing device is configured as described above, it is a galvano-mirror system! When precision tracking is performed using the II device (5), the movable carriage (
13), the amount of shift of the light beam re-entering the fixed optical system (2) changes, and the tracking sensor offset of the light beam returning to the fixed optical system (2) becomes thick (produced). At the same time, this tracking
There is a problem in that the sensor offset amount is not a function of the rotation angle of the reflecting mirror (6) but is also affected by the position of the movable carriage (13).

This will be explained with reference to FIG. The explanatory diagram of Fig. T58 shows the details of the optical path of the light beam in the configuration of Fig. 7, and shows the case where the movable carriage (13) is at a position P close to the fixed optical system (2) and the case where the movable carriage (13) is located at a position P close to the fixed optical system (2). This shows a case where the camera is located at a far position Q. In the figure, αp, (2
q is the shift amount of the chief ray, δP, δQ are the tracking amounts,
θ indicates the amount of rotation of the reflecting mirror (6). As shown in the figure, the rotation angle θ of the reflecting mirror (6) is adjusted by the galvanometer mirror control unit (5) when the movable carriage (13) is at position P and when it is at position Q to achieve the same tracking. Suppose that the adjustment is made by the amount δP−δQ. In this case, although the intended purpose of precisely adjusting the light beam to an arbitrary tracking position on the optical disk (8) can be achieved, the light beam is reflected on the optical disk (8) and passes from the objective lens (9) to the triangular prism (14). A fixed optical system (
The tracking sensor offset amount returned to 2) differs between positions P and Q of the movable carriage (13) as αP>αQ. This causes a problem in that the tracking control system is affected by the position of the movable carriage (13) and accurate tracking control cannot be performed.

This invention was made in order to solve the above-mentioned problems, and provides an optical information recording and reproducing device that suppresses changes in tracking sensor offset amount depending on the tracking position, and that is simple, compact, and economical. The purpose is to obtain.

[Means for Solving the Problems] In order to achieve the above object, an optical information recording and reproducing device according to the present invention has an information recording and reproducing position of an information medium on which information is optically recorded and reproduced, that is, a tracking position. an objective lens that condenses a light beam to a target lens, a holding means such as a parallel plate spring that supports the objective lens movably only in the focus adjustment direction, and a holding means such as a parallel plate spring that supports the objective lens so as to be movable only in the focus adjustment direction; The focus adjustment means for adjusting the focus of the light beam with respect to the information recording/reproducing position and the holding means for the objective lens can be moved through an element whose shape changes piezoelectrically in a direction perpendicular to the focus adjustment direction of the objective lens, that is, in the tracking direction. A movable support means for supporting the information medium, and a position adjustment means for controlling the movable support means to adjust the position of the light beam relative to the information recording/reproducing position of the information medium, that is, the tracking position.

[Function] In the above means, the optical information recording/reproducing apparatus of the present invention suppresses changes in the amount of shift of reflected light from the information medium due to tracking control to a small value, and further makes changes in this amount of shift irrelevant to the tracking position. ing.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an optical information recording/reproducing apparatus according to an embodiment of the present invention. The parallel plate springs (12a) and (12b) are installed between the carriage (13) and the lenses are connected by applying voltage.
It is a laminated piezoelectric element that can be moved in the direction of the arrow along with the holder (10) and objective lens (9). In addition to the above, the configuration shown in FIG. 1 differs from the configuration shown in FIG.
This is the point leading to the triangular prism (14) in 3).

FIG. 2 is a perspective view of the movable carriage (13) in FIG. 1, and FIG. 3 is a plan view of the same. In each figure, (17a)
, (17b) moves the movable carriage (13) to the optical disk (
Bearings (18a), (18) in the tracking control direction of
b) a shaft held movably via (19a), (
19b) moves the movable carriage (13) to the shaft (17g), (17b) by electromagnetic force between it and a permanent magnet (not shown).
) for driving in the direction of the arrow, (20
a), (20b) are back yokes (21a), (
21b) and a focus coil (11) to drive the lens-holder (10) in the direction of arrow C and adjust the focus of the objective lens (9) on the optical disk (8).

The operation of this configuration will be explained next.

The light beam (3) emitted from the fixed optical system (2) is reflected by the triangular prism (14) on the movable carriage (13) and passes along the optical axis of the objective lens (9).
) and is focused on the optical disk (8) to form a light spot. This light spot is modulated when recording information, and information corresponding to the modulation is recorded on the optical disk (8). On the other hand, when reproducing information, the optical disc (8) is
) is modulated, and this reflected light passes through the objective lens (
9), returns to the fixed optical system (2) in the reverse path through the triangular prism (14), and is detected by a photodetector (not shown). Note that regardless of whether information is being read or written, the reflected light from the optical disk (8) is returned to the fixed optical system (2) and used for focus control and tracking control.

When selecting an arbitrary track on the optical disk (8), the movable carriage (13) is driven in the direction of arrow A through a feeding mechanism consisting of a permanent magnet (not shown) and coils (19a) and (19b) to track the track. Parallel leaf springs (12a), which support the objective lens (9) via the lens holder (10) by making coarse adjustments in position and then adjusting the voltage applied to the laminated piezoelectric element (15);
12b) in the direction of the arrow to finely adjust the position of the light spot focused on the optical disk (8) in the tracking direction by moving the objective lens (9) in parallel.

In addition, when adjusting the focus of the optical spot on the optical disk (8) by the objective lens (9), the permanent magnet (20
a), (20b) and back yoke (21a), (21
b) parallel leaf springs (12a), (12
b) A movable carriage (
The lens holder (10) supported by the lens holder (13) is driven in the direction of arrow C, that is, in the optical axis direction of the objective lens (9), and the focus direction of the objective lens (9) held by the lens holder (10) is moved. Adjusting the position.

The explanatory diagram in FIG. 4 shows the details of the optical path of the light beam in the configuration shown in FIG. This shows the case where the location Q is far from the location Q.

As shown in the figure, when fine adjustment of the tracking position is performed by applying a voltage to the laminated piezoelectric element (15) whether the movable carriage (13) is at position P or position Q, the movable carriage (13) Regardless of the position of the objective lens (9)
) for the same amount of movement, the same amount of tracking δP−δQ
is obtained. In other words, regardless of the position of the movable carriage (13), the amount of movement of the objective lens (9) by the laminated piezoelectric element (15) may be adjusted to be the same for the same tracking deviation.

As a result, the initial objective of precisely adjusting the light beam to an arbitrary tracking position on the optical disk (8) can be achieved through a control system that controls the voltage applied to the laminated piezoelectric element (15). On the other hand, the tracking sensor offset amount reflected on the optical disk (8) and returned from the objective lens (9) to the fixed optical system (2) through the triangular prism (14) is also Since the control amount of the objective lens (9) is the same, there is little change, and since the tracking control system is not affected by the position of the movable carriage (13), accurate tracking control is possible.

Furthermore, according to the configuration of the present invention, there is no need for a galvanometer/mirror control unit for fine-tuning tracking or a triangular prism for guiding the light beam from the fixed optical system to this unit, making it extremely thin and compact. It can be constructed economically.

In the above embodiment, the movable carriage (13) and the fixed optical system (2) are installed separately, but as shown in the schematic configuration diagram of FIG. The system (two people) may be housed in a movable carriage (13).

In this case as well, fine tracking adjustment is performed using a laminated piezoelectric element (
15) is carried out in exactly the same way as in the case of the configuration of FIG. Further, in the above embodiment, the focus control system includes a focus coil (11), a permanent magnet (20a), (20
b) and back yokes (21a), (2'lb), but as shown in the schematic diagram of FIG.
According to b), a piezoelectric drive system may be used to control focus by driving the objective lens (9) in the direction of arrow C, which is the focus control direction. In this case as well, fine adjustment of tracking is performed through the laminated piezoelectric element (15) in exactly the same way as in the case of the configuration shown in FIG.

Further, in the above embodiment, a configuration using an optical disk as an optical information recording medium was exemplified, but it goes without saying that the present invention can be applied to any device that records and reproduces information using light, such as an optical card. be.

[Effects of the Invention] As described above, according to the present invention, the focusing position of a light beam for reading and writing information to an optical information recording medium is adjusted by moving the objective lens in parallel using a piezoelectric element. Because of this structure, the shift amount of the light beam due to adjustment of the light beam position can be suppressed to a small value, and since the incident light beam is not angled, the amount of position sensor offset due to the rough adjustment position for reading and writing information can be reduced. This has the effect of making it possible to implement an optical information recording/reproducing device with an extremely compact and economical configuration and excellent position adjustment performance.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an optical information recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a diagonal view of the configuration shown in FIG. 1, and FIG. 3 is a plan view of the configuration shown in FIG. 1. , FIG. 4 is an explanatory diagram of the optical path in the configuration of FIG. 1, FIGS. 5 and 6 are schematic configuration diagrams showing modifications of the configuration of FIG. 1, and FIG. 7 is a conventional optical information recording/reproducing device. FIG. 8 is an explanatory diagram of the optical path in the configuration of FIG. 7. In the figure, (2) is a fixed optical system, (8) is an optical disk, (9) is an objective lens, (10) is a lens holder, (
12a), (12b) 4; are parallel leaf springs, (13)
is a movable carriage, and (15) is a laminated piezoelectric element. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent: Patent attorney Masuo Oiwa (2 others) Schematic structure of a modification of the structure shown in Fig. 1. Fig. 5 Procedural amendment (voluntary) 5. Subject of amendment September 4, 1 Column for detailed description of the invention. 6. Contents of amendment 2. Name of the invention Optical information recording and reproducing device 3. Name of person making the amendment (601) Mitsubishi Electric Corporation Representative Moriya Shiki 4 Address of agent 2-2 Marunouchi, Chiyoda-ku, Tokyo 3 or more

Claims (1)

[Claims] An objective lens that focuses a light beam on an information recording/reproducing position of an information medium on which information is optically recorded and reproduced; a holding means that movably supports the objective lens in a focus adjustment direction; A focus adjustment means that is driven in the focus adjustment direction to adjust the focus of the light beam to the information recording/reproducing position, and an element that piezoelectrically changes the shape of the objective lens holding means in a direction perpendicular to the focus adjustment direction of the objective lens. An optical information recording/reproducing apparatus characterized by comprising: a movable support means for movably supporting the movable support means; and a position adjustment means for controlling the movable support means to adjust the position of the light beam with respect to the information recording/reproducing position of the information medium. Device.