JPH02177134A - Optical recording medium driving device - Google Patents

Abstract

PURPOSE:To diminish mass of inertia which acts on a movable part of a separated optical system and to highly speed up access time and also to improve the durability of each part of the device by providing an autofocus means to a part except an objective lens. CONSTITUTION:A fixed part 12 is constituted of a light source 1, a collimator lens 4, a beam splitter 11, two convex lenses 31 and 32 for autofocus and a photodetector, while a movable part 16 is constituted of two optical path changing mirrors 34 and 35 and the objective lens 14. Then, when the autofocus means consisting of the convex lenses 31 and 32 and an actuator 33 is disposed to the fixed part 12 of the separated optical system, the weight of the movable part 16 can be reduced at least by the weight of a member constituting the autofocus means. By this method, the mass of inertia for acting on the movable part 16 is diminished, thus enabling the high speed access time and improving the durability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical recording medium drive device equipped with a separating optical system, and particularly to the arrangement of an autofocus means provided in the optical system.

[Conventional technology]

Conventionally, the image forming apparatus has been configured to include at least a light source, a fixed part that is set at a fixed position with respect to an optical recording medium drive part, and at least an objective lens.

An optical recording medium drive device is known that includes a separation optical system including a movable section that is movable in the tracking direction of the optical recording medium set in the optical recording medium drive section.

7 and 8 show an optical recording medium drive device equipped with a conventionally known swing arm type separating optical system (NIKKEI ELECTRONIC51988, 4).
, 18, pp. 211-224).

FIG. 7 is a perspective view of this optical recording medium drive device, showing a light source 1, a collimator lens 4 that transforms a diffused beam 2 emitted from the light source 1 into a parallel beam 3, and reflected light from an optical recording medium 5. 6, and optical recording medium 5.
A fixed part 12 is fixed at a fixed position on the substrate 13 and includes a beam splitter 11 that guides the reflected light 6 from the photodetectors 7 to 10. Note that the photodetector 7 is a photodetector for detecting a focus error, the photodetector 8 is a photodetector for detecting a tracking error, and the photodetectors 9 and 10 are photodetectors for detecting a Kerr rotation angle.

On the other hand, a movable part 16 consisting of an objective lens 14 and a parallelogram prism 15 is rotatably supported at one end on the substrate 13, and is moved in the tracking control direction of the optical recording medium 5 (in the direction of arrows A and H). ) is mounted on a swing arm 17 that rotates.

An actuator 18 for autofocus is provided around the objective lens 14.
The condensing position of the light beam narrowed down by the optical recording medium 5 is controlled in the optical axis direction by following the fluctuation of the recording surface of the optical recording medium 5.

The autofocus actuator 18 is.

As shown in FIG. 8, it consists of a lens drive coil 19 attached to the objective lens 14 and a magnet 20 placed around it.

A galvanometer mirror 21 is set between the fixed part 12 and the movable part 16, and an optical path connecting the two parts is constructed.

In addition to the above-mentioned swing arm type optical recording medium drive device equipped with a one-separation optical system, there is also an optical recording medium drive device in which the movable part is mounted on a carriage that moves along a guide rail extending in the tracking direction of the optical recording medium. So-called linear optical recording medium drive devices have also been known.

In the optical recording medium drive described above, the optical system is separated into the fixed part 12 and the movable part 16, so the movable part is lighter compared to an optical recording medium drive of the type that transports all the optical devices as one. Therefore, the average access time can be increased, and durability can be improved by reducing the load on the movable part and its supporting part.

[Problem to be solved by the invention]

However, in the conventional optical recording medium driving device described above, since the objective lens 14 is provided with an actuator 18 for autofocusing, the weight of the movable part 16 cannot be sufficiently reduced, and therefore, the access time can be increased and The problem remains that it is not possible to sufficiently improve durability by reducing the burden on the movable parts and their supporting parts.

Therefore, the present invention further promotes weight reduction of the movable part,
It is an object of the present invention to provide an optical recording medium drive device with even shorter access time and excellent durability.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides an autofocus means for tracking the condensing position of a light beam narrowed down by an objective lens to fluctuations in the recording surface of an optical recording medium. It was provided near the rotation center of the swing arm of an optical recording medium drive device having a fixed part of the system or a swing arm type separation optical system.

[Effect]

When the autofocus means is disposed in the fixed part of the separation optical system, the weight of the movable part can be reduced by at least the weight of the members constituting the autofocus means. Therefore, when the movable part is driven at high speed, the inertial mass that acts on the movable part becomes small, making it possible to further speed up the access time. Furthermore, since the inertial mass acting on the movable part is small, the burden on the movable part and its supporting parts is reduced, and durability can be further improved.

Also, in the swing arm type separation optical system.

Since an inertial mass proportional to the square of the distance from the center of rotation to the center of gravity acts, if the autofocus means is installed near the center of rotation of the swing arm, the center of gravity can be moved closer to the center of rotation, and the center of gravity can be moved closer to the center of rotation. The inertial mass can be reduced. Therefore, it is possible to speed up access time and improve durability.

Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is an optical configuration diagram of the optical recording medium drive device according to the first embodiment, and FIG. 2 is an optical configuration diagram showing the operating principle of the optical system shown in FIG. 1 rearranged in a plane. In these figures, 31 and 32 are convex lenses for autofocus, 33 is an actuator for autofocus, and 3
Reference numerals 4 and 35 indicate optical path changing mirrors, and other members similar to those shown in FIG. 7 are designated by the same reference numerals. In addition, in these figures, illustrations of photodetectors that are not the subject of the present invention are omitted to simplify the drawings.
x

As shown in these figures, the optical recording medium driving device of this embodiment includes a light source 1 and a collimator lens 4.

The fixed part 12 includes a beam splitter 11, two convex lenses 31 and 32 for autofocus, and a photodetector (not shown).

Furthermore, a movable section 16 is constituted by two optical path changing mirrors 34 and 35 and an objective lens 14, and this movable section 16 is mounted on a swing arm 17 that rotates around an axis XX. .

The autofocus actuator 33 is provided on the first convex lens 31, which is disposed close to the light source, of the two autofocus convex lenses 31 and 32 described above.

A diffused beam 2 emitted from a light source 1 passes through a collimator lens 4 and is converted into a parallel beam 3, which is then sent to a beam splitter 1.
1. The light passes through convex lenses 31 and 32 for autofocus, a galvanometer mirror 21, and optical path changing mirrors 34 and 35, enters the objective lens 14, and is focused on the recording surface of an optical recording medium (not shown).

When the light beam narrowed down by the objective lens 14 is focused on the recording surface of the optical recording medium, the reflected light from the optical recording medium is returned to the beam splitter 11 through the opposite optical path. In this case, the light beam once narrowed down by the second convex autofocus lens 32 passes through the first convex autofocus lens 31 and becomes a parallel light beam again,
The light is reflected by the beam splitter 11 and guided to a photodetector (not shown).

When the relative distance between the optical recording medium and the objective lens 14 increases during driving, the reflected light from the optical recording medium that has passed through the autofocus convex lenses 31 and 32 becomes a convergent light beam. The deviation of this convergent light beam from the parallel light beam is detected by a photodetector (not shown), and the autofocus actuator 3
3 to operate the first autofocus convex lens 31 in the direction of returning the light beam to a parallel beam, the light emitted from the objective lens 14 can be focused again on the recording surface of the optical recording medium.

On the other hand, when the relative distance between the optical recording medium and the objective lens I4 becomes smaller than the in-focus position, the reflected light from the optical recording medium that has passed through the autofocus convex lenses 31 and 32 becomes a diffused light flux. Therefore, by detecting the amount of deviation of the diffused light beam from the parallel light beam with a photodetector and driving the autofocus actuator 33, the light emitted from the objective lens 14 is directed onto the recording surface of the optical recording medium in the same manner as described above. You can refocus.

As a means for detecting the amount of deviation of the reflected light from the optical recording medium from the parallel light beam, in addition to using a photodetector as described above, any known method such as the astigmatism detection method or the knife detection method can be used. Means can be used.

In the optical recording medium drive device of the above embodiment, since the autofocus convex lenses 31 and 32 and the autofocus actuator 33 are provided on the fixed part 12 of the separate optical system, installation of an autofocus means on the objective lens 14 is omitted. Therefore, the weight of the movable portion 16 can be reduced by at least the weight of the members constituting the autofocus means. Therefore, the inertial mass acting on the movable part 16 can be reduced, and the access time can be further increased and the durability of the movable part 16 and its support part can be further improved.

Next, a second embodiment of the present invention will be described based on FIG.

FIG. 3 is an optical configuration diagram showing the operating principle of the optical system of the optical recording medium drive device according to the second embodiment rearranged in a plane, and the same members as shown in FIG. 2 are the same. The sign is displayed.

As shown in this figure, in the optical recording medium driving device of this embodiment, the actuators 33 for autofocus 1 to focus are arranged close to the objective lens 14 of the two autofocus convex lenses 31 and 32. second convex lens 32
It is characterized by the fact that it is provided in For other configurations,
This is the same as the first embodiment.

The optical recording medium drive device of this embodiment also has the same functions and effects as those of the first embodiment.

Next, a third embodiment of the present invention will be described based on FIG.

FIG. 4 is an optical configuration diagram showing the operating principle of the optical system of the optical recording medium drive device according to the third embodiment rearranged in a plane, and the same members as shown in FIG. 2 are the same. The sign is displayed.

As shown in this figure, the optical recording medium drive device of this embodiment has one convex focusing lens 3 in the fixed part 12.
1 is arranged, and this convex lens 31 is provided with an actuator 33 for autofocus. For other configurations, i′i? This is the same as the first embodiment of Book J.

The optical recording medium drive device of this embodiment also has the same functions and effects as those of the first embodiment.

Next, a fourth embodiment of the present invention will be described based on FIG. 5.

FIG. 5 is an optical configuration diagram of an optical recording medium drive device according to a fourth embodiment, in which the same members as shown in FIG. 1 are denoted by the same reference numerals.

As shown in this figure, the optical recording medium drive device of this embodiment has one autofocus convex lens 31 between two optical path changing mirrors 34 and 35 arranged in a movable part 16.
is arranged, and this convex lens 31 is provided with a seven-couple unit 33 for autofocusing. These autofocus convex lens 31 and autofocus actuator 33 can be placed at any position between the two optical path changing mirrors 34 and 35, but when the swing arm 17 is driven, the autofocus actuator 33 acts on the movable part 16. In order to reduce the inertial mass, it is preferable to arrange it as close to the first optical path changing mirror 34, which is arranged as close to the axis XX as possible.

The other configurations are the same as those of the first embodiment.

In the optical recording medium driving device of this embodiment, the autofocus convex lens 31 and the autofocus actuator 33 are arranged between the two optical path changing mirrors 34 and 35, so when the autofocus actuator is provided in the objective lens 14, Compared to the above, the center of gravity of the movable part [6] can be moved closer to the axis x--x of the swing arm I7.

Therefore, it is possible to reduce the inertial mass acting on the movable portion 16, and it is possible to speed up access time and improve durability.

In the circuit configuration of this embodiment, two autofocus convex lenses are arranged coaxially between the two optical path changing mirrors 34 and 35, and one of these two autofocus convex lenses is connected to the autofocus actuator 33. It can also be driven by.

Next, a fifth embodiment of the present invention will be described based on FIG. 6.

FIG. 6 is a plan view of the optical recording medium drive device according to the fifth embodiment, in which 41 is a guide rail extending in the tracking control direction of the optical recording medium, and 42 is an optical system along the guide rail 41. Reference numeral 43 indicates a carriage for transporting the movable part, and a fixed table on which the fixed part of the optical system is mounted, and other members similar to those shown in FIG. 1 are denoted by the same reference numerals.

As shown in this figure, the optical recording medium drive device of this embodiment applies the present invention to a so-called linear separating optical system that moves the movable part 16 along the guide rail 41 in the tracking control direction of the optical recording medium 5. The fixed table 43
Two convex lenses 31 and 32 for autofocus are coaxially arranged on the fixed part 12 mounted on the fixed part 12, and an actuator 33 for autofocus is provided on the first convex lens 31 disposed close to the light g1. .

The optical recording medium drive device of this embodiment also has the same functions and effects as the optical recording medium drive device of the first embodiment described above.

Note that in the component configuration of this embodiment, an actuator 33 for autofocus is provided on the second convex lens 32 disposed close to the objective lens 14, and one convex lens for autofocus is disposed coaxially on the fixed part 12. However, this autofocus convex lens can also be driven by an autofocus actuator.

The optical recording medium drive device of the present invention can be applied not only to an optical disk drive device but also to an optical card instant drive device for driving a card-shaped optical recording medium.

〔Effect of the invention〕

As explained above, the optical recording medium drive device of the present invention includes:
Since the autofocus means is provided in a part other than the objective lens, the inertial mass acting on the movable parts of the separation optical system can be reduced, further speeding up the access time and further improving the durability of each part of the device. can be achieved.

[Brief explanation of the drawing]

FIG. 1 is an optical configuration diagram of the optical recording medium drive device according to the first embodiment, FIG. 2 is an optical configuration diagram showing the operating principle of the optical system shown in FIG. 1 rearranged in a plane, and FIG. FIG. 4 is an optical configuration diagram showing the operating principle of the optical system of the optical recording medium driving device according to the second embodiment arranged in a plane, and FIG. FIG. 5 is an optical configuration diagram of the optical recording medium drive device according to the fourth embodiment, and FIG. 6 is an optical configuration diagram showing the operating principle in rearranged format. FIG. 7 is a plan view and a perspective view of an optical recording medium drive device equipped with a conventionally known swing arm type optical system. FIG. 8 is a sectional view showing an example of autofocus means. I: light source, 4: collimator lens, 5: optical recording medium, 7
~10: Photodetector, 11: Beam splitter, 12: Fixed part, 13: Substrate, 14: Objective lens, 15: Parallelogram prism, 16: Movable part, 17: Swing arm, 1
8: Actuator. 19: Lens drive coil, 20: Magnet l-. 21: Galvanometer mirror, 31. 32: Convex lens for autofocus, 33 Nio-1-focus actuator, 34, 35: Optical path changing mirror 41: Guide rail, 4
2: Carriage, 43: Fixed table. 1st, 5 1: Light source, 16: Possible #7 tatami ll: Himushuuri 7 12: Fixed 4p 14: Laptop, 8th, convex lens. , 33: fang-ni car〃also side a7+any7 14wJ jI5 Figure 2 Figure 3 Figure 6/

Claims (8)

[Claims] (1) An optical recording medium configured to include at least a light source and provided at a fixed position relative to the optical recording medium drive unit, and an optical recording medium configured to include at least an objective lens and attached to the optical recording medium drive unit. In the optical recording medium drive device, the optical recording medium drive device includes a separation optical system comprising a movable part that is movable in a tracking control direction, and records the converging position of the light beam narrowed by the objective lens on the optical recording medium. An optical recording medium driving device characterized in that an autofocus means for controlling in the optical axis direction in accordance with surface fluctuations is provided in a portion other than the objective lens. (2) In the optical recording medium driving device according to claim 1, the movable part is mounted on a swing arm whose one end is rotatably supported and which rotates the objective lens in a tracking control direction of the optical recording medium. An optical recording medium drive device characterized by: (3) The optical recording medium drive device according to claim 1, wherein the movable part is mounted on a carriage that moves along a guide rail extending in a tracking control direction of the optical recording medium. Media drive. (4) The optical recording medium driving device according to claim 2, wherein the autofocus means is provided near the center of rotation of the swing arm. (5) The optical recording medium driving device according to claim 2 or 3, wherein the autofocus means is provided on the fixed portion. (6) In the optical recording medium drive device according to claim 1,
Two convex lenses are disposed coaxially as the autofocus means on the optical path from the light source to the objective lens, and an actuator is provided on one of the two convex lenses to drive it in the optical axis direction. Features of optical recording medium drive device. (7) In the optical recording medium drive device according to claim 1,
An optical recording medium driving device characterized in that a convex lens is disposed as the autofocus means on the optical path from the light source to the objective lens, and an actuator for driving the convex lens in the optical axis direction is provided on the convex lens. (8) The optical recording medium drive device according to claim 6 or 7, wherein the actuator is composed of a lens drive coil attached to the convex lens and a magnet arranged around the lens drive coil. Optical recording medium drive device.