JPH05128556A - Optical disk device - Google Patents

Abstract

PURPOSE:To make it possible to detect the amount of displacement of an objective lens in analog mode from the output of an optical device by laying out a projected part integrally installed to a movable body which holds the objective lens at a light passage portion of the optical device. CONSTITUTION:When carrying out control in a tracking direction, a finned portion 115a moves in the direction marked with the arrow E within a gap of a photo-interrupter 110 in proportion to a controlled variable in the tracking direction. Therefore, it is possible to detect the controlled variable as an analog value optically. The finned portion 115a projects to a supporting shaft 103 in parallel so that it may be immune to the amount of movement in the focusing direction. Furthermore, it is possible to detect accurately only the controlled variable in the tracking direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device,
In particular, the present invention relates to an optical disc device including an objective lens driving device section for controlling the position of a light spot focused on an optical information recording medium.

[0002]

2. Description of the Prior Art FIGS.
FIG. 9 is a diagram showing an objective lens driving device section mounted in a conventional optical disk device disclosed in Japanese Patent Laid-Open No. 116618, FIG. 9 is an exploded perspective view of the conventional objective lens driving device section,
FIG. 10 is a perspective view of an assembled state of a conventional objective lens driving device section, FIG. 11 is a horizontal sectional view of FIG. 10, and FIG. 12 is a vertical sectional view of FIG. FIG. 13 is a block diagram showing a tracking direction coupling control system composed of an objective lens drive device section which is a first drive control section and a linear motor which is a second drive control section, and FIG. 14 is a conventional optical disc apparatus. FIG. 5 is a schematic diagram showing frequency characteristics in a tracking direction of a tracking direction coupling control system including an objective lens driving device section which is a first driving control section and a linear motor which is a second driving control section.

In the figure, 20 is a base, 20a is a protrusion provided at the center of the lower surface of the base 20, 21 is an internal hole of the protrusion 20a, and 22 is a lower end fixed to the internal hole 21. Support shafts 23 and 24 are formed on the upper surface of the base 20 so as to form a part of an arc centered on the axis of the support shaft 22 for focus and tracking adjustment, and 25 is the base. Light window provided on the base 20, 2
Reference numeral 6 denotes an objective lens holder formed in a substantially rectangular shape, 27 and 2
Reference numeral 8 is an arcuate portion formed on opposite short sides of the objective lens holder 26, reference numeral 29 is a bearing hole into which the support shaft 22 is fitted, and reference numerals 30 and 31 are provided on the objective lens holder 26. Notches formed on the opposite long sides connecting the respective sides of the portions 27 and 28, and 32 is a narrow space in which the width across the long sides is smaller than the chord width of the arcuate portions 27 and 28. , 33 is a tube portion projecting downward from the objective lens holding body 26, 34 is a lens hole provided at a position spaced apart to one yoke portion 23 side on the longitudinal side of the objective lens holding body 26, and 35 is an objective lens The objective lens is fixedly held in the lens hole 34 by the lens frame 35a.

Reference numerals 36 and 37 denote focus and tracking adjusting magnets provided so as to face the arcuate portions 27 and 28, 38 denotes a focus adjusting coil wound around the outer peripheral surface of the objective lens holder 26, and 39. Four
Reference numerals 0, 41, and 42 denote tracking adjustment coils wound on the outer peripheral surface of the objective lens holder 26 and wound in a rectangular shape.
One side 39a, 40a, 41 of the height direction of 0, 41, 42
a and 42a are arcuate portions 27 of the objective lens holder 26,
It is attached so that it may be located in the side edge of 28.

Reference numeral 43 denotes the tracking adjustment coil 3
A tape body in which 9, 40, 41 and 42 are jointly arranged is wound around the outer circumference of the objective lens holding body 26. Reference numerals 45 and 46 are coil winding grooves provided in the arcuate portions 27 and 28, and 47 and 48 are horizontal yoke portions which are attached so as to face the upper ends of the focus and tracking adjusting magnets 36 and 37.

Reference numeral 50 is an elastic support member attached to a support pin 51 fixed to the base 20, 52 is a rubber mounting member to which an elastic support plate 53 having a small hole 54 at one end is coupled, and 55 is the above. The balancer pin attached to the objective lens holder 26, 55a is the balancer pin 55
Is a small diameter portion at the tip of the collar, and the collar 56 is press-fitted and fixed through the small diameter portion 55a.

Reference numeral 57 is a fitting hole provided in the objective lens holder 26, 58 is a relay board provided on the upper surface of the objective lens holder 26, and 59 is a lead drawn from the relay board 58. The wire, 60 is the yoke portion 24
61 is a terminal plate provided on the outer peripheral surface of the
0 is a through hole.

Next, the operation will be described. The objective lens holder 26 is driven in the vertical direction, which is the axial direction of the support shaft 22, by the forward and reverse currents flowing in the focus adjustment coil 38 and the magnetic fluxes from the focus and tracking adjustment magnets 36 and 37, thereby performing focus adjustment. To do.

The tracking adjustment coils 39 and 4 are also provided.
One side 39a, 40a, 41a, 42 of 0, 41, 42
The objective lens holder 26 is driven to rotate forward and backward around the axis of the support shaft 22 by the forward and reverse currents flowing in a and the magnetic fluxes from the focus and tracking adjustment magnets 36 and 37, and tracking adjustment is performed.

[0010]

However, in the conventional optical disk device configured as described above, as shown in FIG. 13, the midpoint restoring mechanism in the objective lens drive unit, which is the first drive control unit, is used. Since the resonance peak of the resonance frequency F1 is high, there are a plurality of coupling frequencies at which the gain of the first drive control unit and the gain of the second drive control unit are equal, and the frequency characteristic of the coupling control system is unsatisfactory. It could be stable. Further, when the second drive control unit performs the track seek to the information recording medium in the state where the control of the first drive control unit is released, the objective lens in the first drive control unit vibrates in the tracking direction due to disturbance or the like. Therefore, there is a problem that the track seek time may increase.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an optical disk device which realizes a stable tracking direction control system and can reduce the track seek time.

[0012]

In an optical disk device according to the present invention, an optical element composed of a single light source and a single photodetector is provided in a first drive control section which is an objective lens drive section. By arranging a protrusion integrally provided with a movable body holding the objective lens in the light passage portion of the optical element, the displacement amount of the objective lens in the first drive control unit is output from the optical element. It is configured so that it can be detected in an analog manner.

[0013]

In the present invention, the resonance peak of the first drive control unit is reduced by obtaining the speed amount from the displacement amount of the objective lens and feeding it back on the control circuit. Further, the displacement amount of the objective lens is controlled so as to be a predetermined amount at the time of track seek, and the objective lens is fixed in the first drive control unit so as not to cause unnecessary vibration during the track seek.

[0014]

【Example】

Example 1 FIG. 1 is a perspective view of a main part of an objective lens driving device section, which is a first drive control section mounted in an optical disk device in Example 1 of the present invention, and FIG. 2 is an objective lens in Example 1 of the present invention. 3 is an exploded perspective view of the drive unit, FIG. 3 is a first embodiment of the present invention.
4 is a plan view of a main part of the objective lens driving device section in FIG. 4, FIG. 4 is a sectional view taken along the line AA in FIG. 3, FIG. 5 is a sectional view taken along the line BB in FIG. 3, and FIG. FIG. 7 is a schematic diagram showing a lens displacement amount detection unit, FIG. 7 is a block diagram showing an objective lens velocity feedback system in the first embodiment of the present invention, and FIG. 8 is a first drive control unit of the optical disk device in the first embodiment of the present invention. FIG. 3 is a schematic diagram showing frequency characteristics in a tracking direction of a tracking direction coupling control system composed of an objective lens driving device section which is the above and a linear motor which is a second driving control section.

In the figure, reference numeral 100 designates a base, which has a light beam passing hole 100a on its side surface so that a light beam 101 emitted from a light source (not shown) can enter from the side surface. A focus base 102 holds a lower end of a support shaft 103 coated with a fluororesin having a small friction coefficient. Reference numerals 104a and 104b denote focusing magnets vertically magnetized, which are fixed to the focus base 102 together with the focusing yokes 105a and 105b. The focus base 102 is fixed to the base 101 by fixing screws 106a and 106b. It is fixed.

Reference numerals 107a and 107b are tracking magnets polarized in two poles in the left-right direction, and reference numeral 108 is a launching mirror for vertically reflecting the light beam 101 incident from the side surface, which is fixed to the base 100 by adhesion. ing. Reference numeral 109 is a drive current application FPC, 110 is a photo interrupter, and 111 is the photo interrupter 1 described above.
FPC for photointerrupter connected to 10, 112
Is a plate for fixing the photo interrupter, the FPC 109 for applying the drive current and the photo interrupter 1
10 is fixed to the base 100 by screws 113 and 114, respectively.

Reference numeral 115 denotes a lens holder made of a lightweight and highly rigid plastic material or the like, so that the fin portion 115a protruding in parallel with the support shaft 103 is arranged in the gap portion of the photo interrupter 110. It is provided integrally with the lens holder 115. Reference numeral 116 denotes an objective lens fixed to one end of the lens holder 115 in the longitudinal direction, and 117 denotes a balance weight fixed to one end of the lens holder 115 in which the objective lens 116 is not arranged.

Reference numeral 118 is a bearing fixed to the lens holder 115 so as to have an axis parallel to the optical axis of the objective lens 116, and is fitted to the support shaft 103. Reference numeral 119 is a focusing coil fixed to the lens holder 115 so as to be coaxial with the bearing 118.
2 and the focusing yokes 105a and 105b are arranged in the magnetic gap. Reference numeral 120 denotes a movable part FPC fixed to the lens holder 115, and tracking coils 121a and 121b fixed to both side surfaces of the lens holder 115 by adhesion.
The focusing coils 11 are connected to each other.
9 and the tracking coils 121a and 121b have a function of a relay board for supplying a drive current through the lead wires 122a to 122d.

Reference numerals 124a and 124b denote dampers, which are projections 125a and 12 provided on the lens holder 115.
5b and the pin portion 126a provided on the base 100.
To 126d, respectively, and supports the movable portion 123 so as to be slidable and rotatable with respect to the support shaft 103. 12
A cover 7 is fixed to the base 100.

Next, the operation will be described. In the case of correcting the focus shift of the light spot (not shown), a desired current is applied to the focusing coil 119, and the movable portion 1 is moved by the electromagnetic force obtained by the interaction with the magnetic force generated by the focusing magnets 104a and 104b.
23 and by extension, the objective lens 116 is drive-controlled in the direction of arrow C in the figure to control the focusing direction. Also, when correcting the track deviation of the light spot (not shown),
A desired current is applied to the tracking coils 121a and 121b to cause the tracking magnets 107a and 10b to move.
An electromagnetic force obtained by the interaction with the magnetic force generated by 7b causes the movable portion 123 to rotate about the support shaft 103 in the direction of the arrow D in the figure by the electromagnetic force, and serves as a first drive control unit for the objective lens 116. Controls the tracking direction.

When performing track seek or tracking control, a component with a large amplitude mainly at a low frequency is
Follow-up control is performed by the second drive control unit configured by a linear motor.

When controlling the tracking direction,
As shown in FIG. 6, the fin portion 115a is connected to the photo interrupter 110 according to the control amount in the tracking direction.
Since it moves in the direction of the arrow E in the gap, it is possible to optically detect the control amount as an analog amount. Further, since the fin portion 115a projects parallel to the support shaft 103, it is insensitive to the movement amount in the focusing direction, and it is possible to accurately detect only the control amount in the tracking direction. ..

[0023]

As described above, according to the present invention, as shown in FIG. 8, the coupling frequency in the coupling control system can be limited to one, and a stable control system in terms of frequency characteristics can be realized.

Further, since it is possible to suppress the movement of the objective lens in the tracking direction in the first drive control unit when the track is accessed, there is an effect that the track seek time can be shortened.

Further, since the movement of the objective lens in the tracking direction can be detected by a small optical element composed of a single light source and a single photodetector, the objective lens driving device can be downsized. Therefore, there is an effect that a compact and thin optical disk device can be realized.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of an objective lens driving device according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of an objective lens driving device unit according to the first embodiment of the present invention.

FIG. 3 is a plan view of a main part of an objective lens driving device unit according to the first embodiment of the present invention.

4 is a cross-sectional view taken along the line AA in FIG.

5 is a sectional view taken along line BB in FIG.

FIG. 6 is a schematic diagram showing an objective lens displacement position detection unit in the objective lens driving device unit according to the first embodiment of the present invention.

FIG. 7 is a block diagram showing a feedback system of an objective lens speed amount in the objective lens driving device section in the first embodiment of the present invention.

FIG. 8 is a tracking direction of a tracking direction coupling control system including an objective lens driving device unit that is a first driving control unit and a linear motor that is a second driving control unit of the optical disc device according to the first embodiment of the present invention. It is a schematic diagram showing a frequency characteristic of.

FIG. 9 is an exploded perspective view showing a conventional objective lens driving device section.

FIG. 10 is a perspective view of a conventional objective lens driving device unit in an assembled state.

11 is a cross-sectional view of FIG.

12 is a vertical cross-sectional view of FIG.

FIG. 13 is a block diagram showing a combined control system including a first drive control unit and a second drive control unit.

FIG. 14 shows frequency characteristics in a tracking direction of a tracking direction coupling control system including an objective lens driving device section which is a first driving control section and a linear motor which is a second driving control section in a conventional optical disc apparatus. It is a schematic diagram.

[Explanation of symbols]

 100 Base 100a Luminous flux passing hole 101 Light beam 102 Focus base 103 Support shafts 104a, 104b Focusing magnets 105a, 105b Focusing yokes 106a, 106b Fixing screws 107a, 107b Tracking magnet 108 Launch mirror 109 FPC for driving current application 110 Photo Interrupter 111 FPC for photo interrupter 112 Photo interrupter fixing plate 113, 114 Screw 115 Lens holder 115a Fin part 116 Objective lens 117 Balance weight 118 Bearing 119 Focusing coil 120 Movable part FPC 121a, 121b Tracking coil 122a to 122d Lead wire 123 Movable part 123a, 123b Partial movable part 124a , 124b Dampers 125a, 125b Projections 126a to 126d Pins 127 Cover

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[Procedure amendment]

[Submission date] March 16, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

The present invention has been made to solve the above problems, and an object of the present invention is to provide an optical disk device capable of realizing a stable tracking direction control system and reducing the track seek time.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] Figure 8

[Correction method] Change

[Correction content]

FIG. 8 is a tracking direction of a tracking direction coupling control system including an objective lens driving device unit that is a first driving control unit and a linear motor that is a second driving control unit of the optical disc device according to the first embodiment of the present invention. It is a schematic diagram showing a frequency characteristic of.

Claims (2)

[Claims] 1. An objective lens for converging a light beam on an information track on an optical information recording medium, a first drive controller for controlling the drive of the objective lens in a direction crossing the information track, and the first drive. A second drive control unit for controlling the drive of the entire control unit in a direction crossing the information track;
In the optical disc device, which performs follow-up control of the light beam in a direction crossing the information track by combining the first drive control unit and the second drive control unit in terms of frequency characteristics, the first drive control unit Is provided with an optical element composed of a single light source and a single light receiving section, and a projection portion integrally provided with a movable body holding the objective lens is arranged at a light passage portion of the optical element to provide the objective. By detecting the displacement amount of the lens and feeding back the displacement amount and the speed amount obtained from the displacement amount on the control circuit, the gains of the first drive control unit and the second drive control unit become equal. An optical disk device, characterized in that the frequency is limited to one. 2. An objective lens for converging a light beam on an information track on an optical information recording medium, a first drive controller for controlling the drive of the objective lens in a direction crossing the information track, and the first drive. A second drive control unit for controlling the drive of the entire control unit in a direction crossing the information track;
In the optical disc device for performing follow-up control of the light beam in a direction crossing the information track by combining the first drive control unit and the second drive control unit in terms of frequency characteristics, the first drive control unit Is provided with an optical element composed of a single light source and a single light receiving section, and a projection portion integrally provided with a movable body holding the objective lens is arranged at a light passage portion of the optical element to obtain the objective. The displacement amount of the lens is detected, the displacement amount is controlled when the control by the first drive control unit is canceled and the second drive control unit continuously crosses the plurality of information tracks. An optical disk device, characterized in that unnecessary vibration of the objective lens in the first drive control section is suppressed by holding it on a circuit.