JPS62257639A - Information processor - Google Patents

Abstract

PURPOSE:To simplify the magnetic circuit and to obtain a small-sized, light weight titled processor with low cost by using the 1st coil so as to move at elast an objective lens in an optical head in the 1st direction, and using the 2nd coil to move the lens in the 2nd direction orthogonal to the 1st direction. CONSTITUTION:The objective lens 18 is provided in the optical head 5, the objective lens 18 is moved in the optical head 5 vertically, that is, unidirectionally in approaching/parting to/from the information storage medium 1 and moved by an objective lens drive circuit 20 in response to a signal from an out-of-focus detection circuit 19. Further, a head support is moved laterally with the objective lens 18 and moved within the range of recording area of the medium 1 for accessing. As to the track deviation caused by the eccentricity of the medium 1, the optical head 5 is moved for correction.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an information reproducing device, an information recording and reproducing device, etc. that can read at least information from an information storage medium using, for example, focused light. The present invention relates to an information processing device.

(Prior Art) In general, an optical disk device as an information processing VRM uses a collimating lens (condensing lens), a polarizing beam splitter, and a 1/4
After successively passing through the wavelength plate, the laser beam is focused by an objective lens onto an information storage medium having spiral or concentric tracks, and the laser beam reflected from this information storage medium is passed through the objective lens and the quarter-wave plate. , a light leakage beam splitter, and a light projecting lens (condensing lens), and then detected by a photodetector to read the information recorded on the information storage medium and defocus the objective lens relative to the information storage medium. Detection and track deviation detection on the information storage medium.

Further, the objective lens is supported so as to be movable independently in the optical axis direction and the radial direction, and the objective lens is corrected for defocus by moving the objective lens in the optical axis direction based on the defocus detection result. The tracking deviation of the objective lens is corrected by moving the objective lens in its radial direction based on the tracking deviation detection result.

However, the axial coil and magnetic circuit for moving the objective lens in its forward axial direction, and the radial coil and magnetic circuit for moving the objective lens in its radial direction. Because of this configuration, there are problems in that the magnetic circuit becomes complicated, the entire device becomes large and cumbersome, and the cost increases.

In addition, since only the objective lens is moved to correct track deviation, a driving front bridge must be provided in the optical head for this purpose, which increases the weight of the optical head itself and slows down the access time. .

(Problems to be solved by the invention) This invention has a complicated magnetic circuit, and the entire device is large ff.
This eliminates the disadvantages of 1ffl, high cost, heavy optical head itself, and slow access time.It simplifies the magnetic circuit, makes it smaller and lighter, and lowers cost. It is an object of the present invention to provide an information processing device that can shorten access time and that does not cause deterioration in characteristics.

[Structure of the Invention] (Means for Solving the Problems) The information processing device of the present invention focuses light emitted from a light source onto an information storage medium having a track using an objective lens, and collects light from the information storage medium. an optical head that detects the light of the objective lens with a photodetector; a first coil that is connected and integrated with at least the objective lens in the optical head and that corrects the defocus of the objective lens with respect to the information storage medium;
a second coil connected to the optical head by an elastic body and connected to the optical head; - a second coil for correcting a track deviation with respect to the track; by means of a magnetic circuit which moves at least the objective lens in the first direction and also causes the entire optical head to move in a second direction perpendicular to the first direction by passing a current through the second coil. It is composed of

(Operation) The present invention moves at least the objective lens in an optical head in a first direction using a first coil in order to correct defocus of an objective lens with respect to an information storage medium, and the first coil and a second coil connected by an elastic body to move the entire optical head in a second direction perpendicular to the first direction in order to correct a track deviation with respect to the track of the objective lens. This is what I did.

(Actual 1M Example) Hereinafter, a practical example of the present invention will be described with reference to the drawings.

FIG. 4 shows an information recording and reproducing device as an information processing device. In this figure, 1 is a disk-shaped information storage medium, which is placed on a turntable 3 that is rotationally driven by a drive shaft 2. , is pressed from above by a pressing member 4.

This information storage medium 1 has a recording area on at least one side of which is provided a recording layer that can be recorded or reproduced using a laser beam or the like. In this recording area, a tracking guide (track) by a pre-group is formed in a spiral shape or a concentric circle shape.

An optical head 5 is provided below the information storage medium 1, and is attached to a slide portion 7 provided on a fixed portion 6 so as to be slidable along the radial direction of the information storage medium 1.

For access at the start of recording, reproducing, and erasing information, the main CPU 8 creates a program for moving the optical head 5 and operates the drive circuit 10 for moving the optical head via the D/A converter 9, thereby controlling the entire optical head 5. It is designed to move.

Further, at the time of access, the number of tracking guides provided on the information recording tea body 1 is counted, and the current position of the optical head 5 can thereby be confirmed. That is, the output signal of the track deviation detection circuit 11 is binarized by the binarization circuit 12, and when the optical head 5 crosses one tracking guide, one pulse is generated from the binarization circuit 12. This number of pulses is counted by a counter 13 for counting the number of tracks.

Furthermore, after the access is completed, track deviation correction is started. That is, the photodetector 1 inside the optical head 5 will be described later.
The photoelectric signals obtained from 4 are sent to preamplifier array 1, respectively.
5 and is supplied to the track deviation detection circuit 11 via the arithmetic circuit 16, whereby a track deviation detection signal is obtained.

Then, when the analog switch 17 is activated, the signal is supplied to the optical head movement drive circuit 10,
As a result, the entire optical head 5 is moved to perform track deviation correction.

An objective lens 18 is provided within the optical head 5, and this objective lens 18 is arranged in the vertical direction (
The objective lens 18 is movable only in one axial direction (in the axial direction of the objective lens 18), that is, in one axial direction toward and away from the information storage medium 1. Then, it is moved by the objective lens drive circuit 20 in response to a signal from one defocus detection circuit. Furthermore, just before the defocus servo loop is closed, the analog switch 21 is switched, thereby activating the objective lens automatic retraction circuit 22 and moving the objective lens 18 to the initial position.

In addition, in the figure, 23 is a recording signal processing circuit that generates a recording signal according to information recorded on the information storage medium 1;
4 is a recording light generation circuit that amplifies the amount of light emitted according to the signal of the recording signal processing circuit 23; 25 is an erasing light generation circuit that generates predetermined erasing light; and 26 is a reproduction light generation circuit that generates predetermined reproduction light. , 27 is an analog switch, 28 is the optical drive circuit, 29 is an information signal@reading circuit, 30 is a binarization circuit, 31 is a reproduction signal processing circuit that performs modulation, demodulation, error correction, etc. of the information signal, 32 is an interface circuit.

FIG. 1 shows the movable structure of the optical heged 5, and numeral 41 in this figure is a movable hoe mechanism. This movable structure 41 includes permanent magnets 42.42 and yokes 43.43.
The fixed part 6 constitutes a magnetic circuit 46 that shares the objective lens driving magnetic circuit and the optical head driving magnetic circuit, a head support 48, an optical head driving coil (second coil) 49, and an objective lens 18. , an objective lens support spring 50 as an elastic body, an objective lens fixing member 51, and an objective lens drive coil (first coil) 52, and the slide unit slides as a unit during access/track deviation correction. 7, objective lens 18, objective lens fixing member 51, and objective lens drive coil 5
2, the movable part 5 integrally moves in the vertical direction with respect to the optical head drive coil 49 during defocus correction.
It consists of 4.

That is, the slide portion 7 is provided with a head support 48, and the head support 48 is provided with the objective lens 18.
The optical systems except for the optical system are connected and supported as one. Further, the objective lens 18 is mounted on the head support 48 so as to be transferable. Roughly speaking, the information storage medium 1 is arranged above the objective lens 18, and the laser beam led out from the hole 55 of the head support 48 is focused by the objective lens 18 and irradiated onto the information storage medium 1. The laser beam reflected by the storage medium 1 returns to the objective lens 1.
8 and enters the head support 48 through the hole 55. The objective lens 18 is movable in the vertical direction (two directions: a first direction) with respect to the head support 48, and is capable of correcting defocus caused by warping, surface wobbling, etc. of the information storage medium 1. There is.

Further, the head support 48 is movable in the lateral direction (x direction: second direction) together with the objective lens 18, and is configured to move within the range of the recording area of the information storage medium 1 for access. ing.

Furthermore, regarding track deviations caused by eccentricity of the information storage medium 1, etc., the head support 48 and the objective lens 18 are moved together to correct the track deviations, as will be described later. That is, the entire optical head 5 is moved to correct the track deviation. Note that this track misalignment correction requires a high-band response characteristic, but this is made possible by the strength of the magnetic field, the driving force of four-stronger strength due to the number of turns of the optical head drive coil 49, and the reduction of heavy moving parts. Become.

In addition, since defocus correction in two directions and access/track deviation correction in the X direction are performed by the same magnetic circuit 46, the direction of the magnetic field within the gear tooth area 56 that generates the effective magnetic field is oriented in the Y direction. . For this reason, the permanent magnet 42 is provided in an upright state, and the yoke 4 runs around the permanent magnet 42.
3 are arranged so as to surround it. Note that the gap region 56 that generates this effective magnetic field has a uniform magnetic field everywhere within the movement range of the head support 48 to be accessed.

Two magnetic circuits 46a and 46b are provided, which share the magnetic circuit for driving the objective lens and the circuit for driving the optical head, and are arranged in parallel at a predetermined distance with the yoke 43 inside. There is. Since the force that moves the objective lens 18 and the head support 48 is generated within the gap m1a56 that generates the effective magnetic field, the objective lens 18
8 and the head support 48 have two systems of magnetic circuits 46a.

46b, ie between two permanent magnets 42,42. As a result, two systems of magnetic circuits 46a,
Compared to the case where it is placed outside of 46b, it is possible to improve the efficiency in which force is transmitted during movement.

What's more, it's a gear zone that generates an effective magnetic field across the yoke 43! If! A head support 48 is disposed on the opposite side of 56, and the head support 48 connects two systems of magnetic circuits 46a, 46.
It is sandwiched between the yokes 43 and 43 of b. As a result, the head support 48 is surrounded by the high transmittance material that constitutes the yoke 43, and the magnetic field from the gap region 56 is prevented from leaking and reaching the head support 48 or the objective lens 18. ing.

Furthermore, yokes 43.43 sandwiching the head support 48 extend in the direction in which the optical head 5 moves for access, and this yoke 43.43 serves as a guide for sliding the head support 48 and the objective lens 18. It is also used as.

Further, the optical head driving coil 49 is wound so as to surround the guide yoke 43 in a direction along the same plane. Therefore, since the optical head driving coil 49 extends in the Z direction within the gap region 56 having an effective magnetic field in the Y direction, a force acts in the X direction when current is applied.

Further, the head support 48 has a portion on its upper surface that contacts the optical head drive coil 49.
9 is strongly connected. For this reason, the gap area 5
The force received by the four optical head drive coils in the optical head drive coil 6 is directly transmitted to the head support 48, thereby causing the head support 48 to move. Thereby, the optical head driving coil 49 is connected and integrated with the optical head 3.

In addition, two optical head driving coils 49 are arranged so as to sandwich the objective lens 18 between them, and as a result, a stronger force is obtained during driving than in the case where only one optical head driving coil 49 is used. Increases speed.

In the movable part 54, the objective lens 18 is connected to the objective lens driving coil 52 by the objective lens fixing member 51 at its outer peripheral part.
The objective lens 18 is firmly connected and integrated with the objective lens drive coil 52, so that the objective lens 18 moves in conjunction with the objective lens driving coil 52.

Further, the objective lens driving coil 52 and the optical head driving coil 49 are connected to an objective lens supporting spring 50 made of a plate spring.
The coils 52 and 49 are connected to each other, and both coils 52 and 49 are movable independently of each other.

Further, this objective lens driving coil 52 is configured in a saddle shape, and is arranged so as to straddle the head support 48 and the yoke 43. That is, the objective lens driving coil 5
The part located near the objective lens 18 of 2 is the objective lens 1
It is provided along a direction perpendicular to the optical axis direction (two directions) of the objective lens 18 with 8 in between, and has a twisted relationship with a portion located within the gap region 56. Therefore, a part of the objective lens drive coil 52 extends in the X direction within the gap region 56 having an effective magnetic field in the Y direction, and this allows the objective lens 18 to move in the vertical direction (Z direction).

Further, the thickness of the magnetic circuits 46a and 46b is equal to or thicker than the thickness of the optical head 5.

FIG. 2 schematically shows the optical head 5, in which 61
is, for example, a semiconductor laser array (light source) that emits information reproducing light, recording light, and erasing light. The diverging laser light emitted from the semiconductor laser 61 is converted into substantially parallel light by passing through the light transmitting/receiving lens 62 , and then enters the prism 63 . The laser beam entrance surface of this prism 63 is a refracting surface 63a that is inclined with respect to the optical axis. Therefore, when the laser beam is incident, refraction occurs and the spot size of the laser beam is changed in the refracted direction. Ellipse correction of laser light is performed.

Approximately 100% of the laser light incident on the refraction surface 63a of the prism 63 is reflected by the polarized beam splitting surface 64 provided on the other surface of the prism 63, and the 1/4 wavelength plate 70
After passing through the objective lens 18, the light is focused on the information storage medium 1.

The laser light focused on the information storage medium 1 is reflected on the information storage medium 1, passes through the objective lens 18 and the 1/4 wavelength plate 70 again, and then enters the prism 63 where it is reflected onto the polarized beam splitting surface 64. be returned. Here, the laser light becomes linearly polarized light whose vibration direction is rotated by 90 degrees compared to when it is reflected by the polarized beam splitting surface 64 by reciprocating through the quarter-wave plate 70. Therefore, the laser beam returned to the polarized beam splitting surface 64 passes through this polarized beam splitting surface 64, and the three light separating and reflecting members 65 that are superimposed on the polarized beam splitting surface 64 and are adjacent to each other with an inclination After being reflected by surfaces 65a, 65b, and 65c, the beam passes through polarized beam splitting surface 64 again.

Thereafter, the laser beam passes through the light transmitting/receiving lens 62 through an optical path that is substantially similar to the optical path it took when going from the semiconductor laser array 61 to the information storage medium 1, and passes through the light transmitting/receiving lens 62, which is provided close to the semiconductor laser array 61. Proceed toward photodetector 14. In this case, the light separating and reflecting surfaces 65a, 65b, and 65C are provided non-parallel to the polarized beam splitting surface 64.

For this reason, the polarized beam splitting surface 64 and the photodetector 14
Alternatively, between the semiconductor laser array 61 and the semiconductor laser array 61, the optical axis of the laser beam from the light transmitting system from the semiconductor laser array 61 to the information storage medium 1 and the laser beam from the light receiving system from the information storage medium 1 to the photodetector 14 are connected. The optical axes of the two are inclined to each other.

Here, the light separating and reflecting surfaces 65a, 65b, and 65c are arranged so that the laser beam component reflected by at least one surface intersects with the optical axis of the laser beam of the light transmitting system before piercing the photodetector 14. Directions 65a, 65b, and 65c are set.

Further, the boundary line between the light reflection separation surfaces 65b and 65c is set to be substantially parallel to the direction in which the tracking guide of the information storage medium 1 extends or the direction in which the image of the tracking guide projected on the photodetector 14 extends. There is. moreover,
The laser beam component reflected by the light separation reflection surface 65a is used for defocus detection using the principle of the so-called knife etching method.
A photodetection cell 66a for defocus detection on the photodetector 14.

The light is focused between 66b and 66b.

Further, the laser beam components reflected by the light separation reflection surfaces 65b and 65c are used for track deviation detection using the so-called push-pull method, which uses the diffraction pattern of the reflected light of the focused laser beam from the tracking guide. be done. That is, the far field pattern for the condensed spot of the information storage medium 1 is the light separating reflective surface 65b,
65c, and each light is focused on a photodetection cell 67a; 67b for detecting track deviation of the photodetector 14.

Further, the semiconductor laser array 61 and the photodetector 14 are provided on the same mount 68.

Here, the light transmitting and receiving lens 62 includes a lens for collimating the laser light of the light transmitting system emitted from the semiconductor laser 7 ray 61 and a lens for condensing the laser light of the light receiving system onto the photodetector 14. It is also used as. That is, both the laser light from the light transmitting system and the laser light from the light receiving system pass through this light transmitting and receiving lens 62. Since the laser beam is parallel light between the light transmitting and receiving lens 62 and the objective lens 18 when in focus, the laser beam of the light receiving system is on the same plane as the light emitting point of the semiconductor laser array 61 (at the time of focusing). Since the light is focused on the focal plane of the light receiving lens 62, the light emitting point of the semiconductor laser 61 and the light receiving surface of the photodetector 14 are arranged substantially on the same plane.

Further, the mount table 68 is constructed by integrally connecting a semicircular columnar body 68a with a semicircular arc-shaped frame body 68b, and has a rotatable structure as a whole. In this case, the semiconductor laser array 61 is fixed to the semi-cylindrical body 68a of the mount base 68, and its light emitting point is located at the rotation center of the mount base 68, so that when the mount base 68 rotates, the laser of the light transmission system The optical axis of the light does not shift. and,
As shown in FIG. 3(a) or FIG. 3(b), the focus is placed along the rotational direction of the mount 68 (direction along the circumferential direction when the mount 68 is rotated) or along the chordal direction. A photodetection cell 66a for blur detection.

66b is arranged, and when adjusting the assembly of the optical head 5, by rotating only this mount 68, the defocus detection system y4T! i can now do it. Also,
In order to make such adjustment possible, the laser beam moves on the defocus detection light detection cell 668, 66b in accordance with the direction along the circumference of the mount base 68 and the defocus on the information storage medium 1. The directions are substantially parallel to each other. Further, optical detection cells 67a, 67 for detecting track deviation
b is arranged approximately along the radial (radial) direction of the mount base 68, and as the mount base 68 rotates, the track misalignment detection laser light is applied to the track misalignment detection light detection cell 67a.
, 67b.

Note that a photodetection cell 67a for detecting track deviation.

The prism 63.1/4 wavelength plate 6 is used to adjust the unbalance of the optical display of the laser beam irradiated between the 67b and the m ratio of the laser beam used for defocus detection and track deviation detection.
This can be done by simultaneously moving the mount base 68 and the light transmitting/receiving lens 62 in parallel with respect to 5.

Further, the refractive surface 63a of the prism 63 allows the laser light from the light transmitting system and the laser light from the light receiving system to pass through, but this refractive surface 63a does not allow the laser light L from the light transmitting system to pass through. It functions as a refractive surface for correcting the ellipse of the cross-sectional shape. However, it is effective as a refractive surface for improving defocus detection sensitivity against glare from the light receiving system. That is, a plane including the normal line when the laser beam of the light receiving system is refracted by this refraction surface 63a (the optical axis of the incident light of the laser light of the light receiving system refracted by this refraction surface 63a and the optical axis of the emitted light are both A light detection cell 66a for detecting defocus in the direction along the plane (a plane included in the plane) and in the case of defocus.

When the center of the laser beam is parallel to the moving direction on the prism 66b, when the laser beam of the light receiving system, which is parallel light at the time of focusing, passes through the refraction surface 63a, the cross-sectional dimension of the laser beam changes and the laser beam is directed to the prism 63. (The cross-sectional diameter becomes narrower when the light comes out into the air), thereby increasing the effective imaging magnification of the focused spot on the information storage medium 1 onto the photodetector 14, thereby changing the defocus detection sensitivity. (increase).

As described above, since the support springs and coils in each moving system are independent from each other in the objective lens moving system and the optical head moving system, deterioration of characteristics due to mutual influence does not occur.

Further, since the objective lens 18 is surrounded by the objective lens driving coil 52, and the heights of the objective lens 18 and the objective lens driving coil 52 are approximately equal, the force of the coil is easily applied directly to the objective lens 18, and the objective lens 18 is This makes it difficult for the movement of the lens 8 to be delayed or the objective lens 18 to be tilted.

Furthermore, since the magnetic circuit for driving the objective lens for defocus correction and the magnetic circuit for driving the optical head for correcting track deviation and access are shared by the same magnetic circuit 46, the entire magnetic circuit has been simplified and
can be made smaller, lighter, and lower in cost.

Further, since the objective lens drive coil 52 and the four optical head drive coils existing in the effective magnetic field of the gap region 56 of the magnetic circuit 46 are orthogonal to each other, when current is applied to the objective lens drive coil 52 The moving direction of the objective lens 18 and the moving direction of the optical head support 48 when a current is applied to the optical head driving coil 49 are orthogonal to each other. Therefore, when a 7Ii current is applied to the coil in one direction, it does not affect the other drive system (drive direction). Further, for example, when the objective lens 18 moves, the optical head support 48 moves by the force, and conversely, when the optical head support 48 moves, the objective head 18 moves by the force. Movement of one does not mechanically affect the other.

Further, the thickness of the optical head 5 is approximately the same as the thickness of the magnetic circuit 46, or thinner than that, and the magnetic circuit 46a
, 46b, the thickness of the device is defined only by the thickness of the magnetic circuit 46, so the thickness of the optical head 5 can be almost ignored.
Therefore, it can be made extremely thin.

Furthermore, since the magnetic circuit 46 is disposed on the fixed part 6, the movable part, that is, the optical head 5, is light, and high-speed access is facilitated.

Note that the configuration of the optical head is not limited to the above embodiment, and the information storage medium may be used for recording information,
/An optical disc that can be erased in addition to playback may be used.

[Effects of the Invention] As detailed above, according to the present invention, the magnetic circuit can be simplified, and the size and weight can be reduced, and the cost can be reduced.
By reducing the weight, the access time can be shortened, and an information processing device that does not cause deterioration of characteristics can be provided.

[Brief explanation of drawings]

The drawings show a practical example of the present invention; FIG. 1 is a perspective view showing the movable groove of the optical head, FIG. 2 is a perspective view schematically showing the optical head, and FIG. b) is a front view showing different arrangements of photodetection cells, and FIG. 4 is a block diagram showing the configuration of the information recording/reproducing apparatus. 1... Information storage medium, 5... Optical head, 14...
- Photodetector, 18... Objective lens, 42... Permanent magnet, 43... Yoke, 46... Magnetic circuit, 49...
・Second coil (optical head drive coil), 5o...
- Elastic body (spring for supporting objective lens), 52... First coil (lens for driving objective lens), 56... Gap region, 61... Light 3'! (Semiconductor laser array)
.

Claims (7)

[Claims] (1) An optical head that focuses light emitted from a light source onto an information storage medium having a track using an objective lens, and detects the light from the information storage medium using a photodetector; and at least an objective in the optical head. a first coil connected and integrated with the lens for correcting defocus for the information storage medium of the objective lens; connected with the first coil by an elastic body and connected and integrated with the optical head;
a second coil for correcting track deviation with respect to the track; and moving at least the objective lens in the optical head in a first direction by passing a current through the first coil;
An information processing device further comprising: a magnetic circuit that moves the entire optical head in a second direction perpendicular to the first direction by passing a current through the second coil. (2) The information processing apparatus according to claim 1, wherein at least two systems of the magnetic circuit are provided, and an objective lens is present between them. (3) The information processing device according to claim 1, wherein the elastic body is composed of a leaf spring. (4) The first or second coil is firmly connected to an optical head, and as the connected coil moves, the optical head also moves. The information processing device described in the section. (5) The first or second coil is firmly connected to an objective lens, and as the connected coil moves, the objective lens also moves. The information processing device described in the section. (6) One of the first or second coils is wound along a plane, and the other coil is not wound along a single plane, but in a partially twisted relationship. The information processing device according to claim 1, characterized in that the information processing device is configured to be wound. (7) The information processing device according to claim 1, wherein the objective lens is sandwiched between a first coil or a second coil.