JPH0836770A - Mechanism for driving information detecting head in optical information recorder/reader - Google Patents

Abstract

PURPOSE:To provide a mechanism for driving information detecting head in which the entirety of the mechanism can be further reduced in size, simplified and the durability and reliability can be remarkably improved in an optical information recorder/reader in which an objective lens movable part is controlled to be moved independently in focusing and tracking directions. CONSTITUTION:A yoke 18 is integrally fixed to an objective lens holder 1, and magnets 2a, 2b are mounted inside the yoke 18. A balance block 5 mounting a balance weight 4 is similarly integrated with a yoke 19 and the magnets 2a, 2b. A holding member for so holding a lens movable part 50 and a balance movable part 51 as to be independently movable in two directions is mounted at hinge suspension coupling parts 6a, 6b, 7a, 7b. A driving coil fixed to a skew base is disposed at a part designated by a broken line. A current is supplied to the coil to allow the part 50 to be move in tracking and focusing directions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system in which information recorded in a track shape on a recording medium is scanned and read by a light spot condensed by an objective lens, and information is recorded on the recording medium. Information recording / reading device, more specifically, a direction perpendicular to the information track corresponding to the movement of the recording medium by detecting the relative position of the information track on the recording medium and the surface of the information track. The present invention relates to an information detection head drive mechanism that always keeps tracking and focusing in optimum states by causing the objective lens to follow each other in two directions perpendicular to the above.

[0002]

2. Description of the Related Art An optical information recording / reading device for reading or recording information from a CD, a mini disc, etc. is put to practical use. The optical information recording / reading device, after accessing the target track at high speed, prevents misreading and keeps a predetermined S / N against the shake of the disc and the like so that the target track does not come off. An automatic tracking mechanism that adjusts the tracking direction (perpendicular to the track direction) and the focusing direction (perpendicular to the surface of the recording medium) so that the light spot of the specified size is always maintained on the recording medium. It is equipped with an automatic focus adjustment mechanism. The conventional optical information recording / reading device has a moving part of the objective lens equipped with the above-mentioned automatic tracking mechanism and automatic focus adjustment mechanism when the posture of use of the device is changed or when excessive acceleration or impact is applied to the device itself from the outside. However, there was a problem that blur and stable operation were lost, and normal reading and writing of information could not be performed. This has been an important problem since the number of CDs and the like has increased in recent years as vehicles and portable types.

Therefore, it is possible to operate in all azimuth postures while accurately maintaining the azimuth of the objective lens of the movable part, and to operate stably against external fluctuations and impacts. A movable device (including an automatic tracking mechanism and an automatic focus adjustment mechanism) such as an optical pickup has been proposed (Japanese Patent Application No. 62-175885). This is to bring the movable part into a mass equilibrium state with respect to the movable tracking direction and the focusing direction, thereby eliminating the influence of external impact and the movement posture, and enabling stable movement in all azimuth postures.

[0004]

By the way, since the recording media in CDs, mini-disc devices, etc. are becoming more and more compact in recent years, miniaturization and simplification of the movable device are also required. In order to achieve downsizing and simplification, many members are connected to the movable part, and the movement of these members following the movable part not only damages the reliability of the movable device and causes a failure, but also This is contrary to miniaturization and simplification. The movable device such as the optical pickup proposed above has a structure in which a current is supplied to the movable portion, and the lead wire of the drive coil is connected to the movable portion. It does not have a shape, and in order to ensure stable operation, it is necessary to secure a space portion beyond the range where the leader line bends. Further, the durability of the leader line itself becomes a problem with respect to repeated bending of the leader line.

Further, since the current is supplied to the movable part, the supporting structure of the movable part is complicated, and it is disadvantageous to integrate the respective parts with plastic for simplifying the structure, resulting in further miniaturization. Will be difficult. An object of the present invention is to solve the above-mentioned drawbacks, to further reduce the size and simplification of the entire mechanism, and to provide an optical information recording / reading device capable of greatly improving the durability and reliability of the device. It is to provide an information detection head drive mechanism.

[0006]

In order to achieve the above object, an information detecting head driving mechanism in an optical information recording / reading apparatus according to the present invention condenses track-recorded information on a recording medium by an objective lens. A device for scanning and reading with a light spot, or reproducing or recording information, wherein a direction perpendicular to the information track is detected by detecting a relative position between the information track and the light spot on the recording medium, In an optical information recording / reading device that independently controls the position of the objective lens in two directions perpendicular to the surface of the information track, the objective lens holder that holds the objective lens functions as a yoke. The lens movable part in which the magnet is fixed to the yoke function part which is designed as a single body and the objective lens holder that holds the objective lens and the quality are The balance block part in which the magnet is fixed to the yoke function part formed by designing the function of the yoke in the same balance block as a single body, the lens movable part and the balance block part in the two directions. A holding member that movably supports each other independently, and a skewer that fixes the holding member and a drive coil that faces the magnetic circuit formed by the yoke and the magnet at a predetermined position. Drive coil fixed to the skew base, the yoke identical objective lens holder and the yoke identical balancing block, and the yoke by means of electromagnetic force action by the magnet. It is configured such that the integral objective lens holder and the balance block portion of the same yoke are independently controlled to move in the two directions in the opposite directions.

[0007]

According to the above construction, it is possible to further reduce the size and simplify the entire mechanism as compared with the conventional optical information recording / reading device. In addition, the durability and reliability of the device are greatly improved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of an information detecting head driving mechanism in an optical information recording / reading device according to the present invention, in which only a lens movable portion and a balance movable portion are extracted and shown. The lens movable portion 50 is a substantially U-shaped yoke 18.
A substantially circular objective lens holder 1, which is the same body as the yoke 18, an objective lens 3 incorporated in the objective lens holder 1, and magnets 2a and 2b mounted inside the yoke 18. And the hinge suspension coupling portions 6a and 6b having a rectangular parallelepiped shape that are provided so as to project from the side portion of the yoke 18.

On the other hand, the balance movable portion 51 includes a substantially U-shaped yoke 19, a substantially circular balance block 5 which is the same body as the yoke 19, and a balance weight 4 mounted on the balance block 5. , Magnets 2c and 2d attached to the inside of the yoke 19, and rectangular hinge suspension coupling portions 7a and 7b projecting from the sides of the yoke 19 are integrally formed. Yoke 18, magnets 2a, 2
b, the space between the magnets 2a and 2b, the yoke 19, the magnets 2c and 2d, and the magnet 2c.
And 2d form magnetic circuits M1 and M2, respectively. The lens movable part 50 and the balance movable part 51 are
The drive coil 8 shown in FIG. 2 is inserted at the drive coil insertion position P shown by the dotted line, which is incorporated in the positional relationship shown in FIG. The drive coil 8 includes a focusing coil 9 and tracking coils 10a and 10b, and is fixed to a skew base 40 (see FIG. 6) described later.

When a current is passed through the focusing coil 9 with the drive coil 8 positioned at the drive coil insertion position P, the current and the magnetic field in the space formed by the magnetic circuit M1 on the lens movable portion 50 side (direction of current) The lens movable portion 50 receives an electromagnetic force in the focusing direction, which is a direction perpendicular to the current direction and the magnetic field direction, and moves. At the same time, the current flowing through the focusing coil 9 on the balance movable portion 51 side is in the opposite direction to the current flowing on the lens movable portion 50 side. The balance movable unit 51 receives and moves the electromagnetic force in the focusing direction opposite to the electromagnetic force received by the lens movable unit 50.

When a current is passed through the tracking coil 10a, this current and the magnetic circuit M1 on the lens movable portion 50 side are also provided.
By the action of the magnetic field (the direction perpendicular to the direction of the electric current) in the space created by the lens movable unit 50, the lens movable unit 50 receives the electromagnetic force and moves in the tracking direction which is the direction perpendicular to the direction of the electric current and the direction of the magnetic field. At the same time, the current flowing in the tracking coil 10b on the balance movable portion 51 side is the tracking coil 1
Since it is in the opposite direction to the current applied to 0a, the balance movable part 5
By the action of the magnetic field in the space created by the magnetic circuit M2 on the first side, the balance movable portion 51 receives and moves the electromagnetic force in the tracking direction opposite to the electromagnetic force received by the lens movable portion 50. The focusing direction and the tracking direction can be driven independently of each other.

FIG. 3 is a partially cutaway view of a hinge suspension (holding member) for movably supporting the lens movable portion and the balance movable portion of FIG. 1 independently in two directions, a focusing direction and a tracking direction. FIG. Through-hole 16 of lens movable part coupling parts 12a and 12b
a, 16b and balance movable part coupling parts 14a, 14b
The hinge suspension coupling portions 6a, 6b, 7a, 7b of FIG. 1 are inserted into the through holes 17a, 17b of
Lens movable part coupling part 12 of hinge suspension 13
a, 12b and balance movable part coupling parts 14a, 14b
The lens movable portion 50 and the balance movable portion 51 are fixed to the.

The hinge suspension 13 is integrally formed of a plastic material. Lens movable part coupling part 12a, 1
2b and the end portions of the upper surfaces of the balance movable portion coupling portions 14a, 14b are connected to the upper end portions of the side members 20, 21, 22, 23 by thin-walled hinge portions 29, 30, 31, 32 shown in FIG. Also, thin hinge portions 33a, 33b, 34a, 34b, 35a, 35 are provided at the end portions of the upper surfaces of the central support portions 39a, 39b connected to the skew base coupling portion 15.
They are connected by b, 36a and 36b. Further side member 2
The end portions of the upper surfaces of 0, 21, 22, 23 are hinge portions 25,
26, 27 and 28 are connected to the end portions of the side surfaces of the support members 11a and 11b. FIG. 4 is a plan view of the hinge suspension 13, in which a hinge similar to the hinge portions 26 to 36b is provided in the lower portion of the hinge suspension 13 and the lower surfaces of the lens movable portion coupling portions 12a and 12b and the balance movable portion coupling portions 14a and 14b. End and side members 20, 2
The lower end portions of 1, 22, 23 are connected to the upper end portions of the support members 11c, 11d similarly to the upper end portions.

FIG. 5 is a plan view of the skew base 40, and FIG. 6 is a rear view of the skew base 40. Objective lens holder housing 4 made of plastic integrally
2. The balance block accommodating portion 41 is formed with the hinge suspension fixing portion 45 at the center. Hinge suspension accommodating portions 43 and 44 are formed above and below the hinge suspension fixing portion 45, and fixing holes 46a, 46b and 46 are formed.
It is fixed to a carriage (information detection head drive mechanism transport unit) (not shown) for positioning the track selected by c. When the skew base 40 is viewed from the back side, the drive coil 8 is fixed near the frame around the hinge suspension fixing portion 45 as shown in FIG.
The end portion of the leader line is drawn to the outermost frame portion. Since the drive coil 8 is fixed to the skew base 40, its leader line does not move.

FIG. 7 is a plan view showing a state in which a hinge suspension in which a lens movable portion and a balance movable portion are combined is incorporated in a skew base. The hinge suspension in which the lens movable portion and the balance movable portion are combined is incorporated with the skew base 40 in the direction of arrow A in FIG. 1 with the back surface of the skew base in FIG. 6 facing downward. The rear surface of the fixing portion 45 and the upper surface of the skew base coupling portion 15 are fixed by welding. Each accommodation section 41, 42,
Each of the lens movable portion 50, the balance movable portion 51, and the hinge suspension 13 housed in 43 and 44 has a clearance so as to be movable to the maximum movement position in the tracking direction. It is also possible to move to the maximum movement position in the focusing direction.

8A and 8B are schematic views for explaining the operation of the information detecting head driving mechanism in the focusing direction according to the present invention. FIG. 8A is a non-driving state, and FIG. The figure shows the state of moving in the fixed amount focusing direction. A focusing state is detected by a sensor (not shown). For example, assuming that a disc 55 such as a CD is located under the information detection head drive mechanism, the focus is dislocated by a slight swell of the CD.
When the surface such as D approaches the lens movable portion as shown by the arrow B, a current is passed through the focusing coil 9 so as to move away the lens movable portion in order to hold a predetermined light spot. Therefore, the lens movable unit 50 is driven upward as indicated by an arrow C while keeping the objective lens surfaces parallel to each other,
It is moved to the position of (b). At the same time, the balance movable portion 51 is moved downward while keeping its upper surface parallel. At this time, the hinge suspension parts 52 and 53 follow the hinge part as a fulcrum.

9A and 9B are schematic views for explaining the operation of the information detecting head driving mechanism according to the present invention in the tracking direction. FIG. 9A shows a state in which the information detecting head driving mechanism is not driven, and FIG. Each of the states is moving in the tracking direction. Tracking is detected independently of the focusing state by a sensor (not shown). For example, when a disk such as a CD moves in the direction of arrow D due to slight undulations or shaft wobbling, the lens is moved to the track being accessed. A current is passed through the tracking coils 10a and 10b so that the parts follow each other. Therefore, as shown in (b), the lens movable unit 50 is moved in the direction of arrow D while keeping the objective lens surfaces parallel. At the same time, the balance movable portion 51 is moved in the direction opposite to the arrow D while keeping its upper surface parallel. At this time, the hinge suspension parts 52 and 53 follow the hinge part as a fulcrum.

In the above embodiment, an example was described in which the lens movable portion and the balance movable portion were individually driven by electromagnetic forces to drive them in opposite directions. However, only the lens movable portion or only the balance movable portion is driven. Similar results can be obtained by driving.

[0019]

As described above, according to the present invention,
In an information detection head drive mechanism, which is capable of moving a lens movable portion independently in two directions, a tracking direction and a focusing direction, and having a mass balance function in the tracking direction and the focusing direction of the lens movable portion, A magnet and a yoke are integrally provided on the movable part of the lens, and the drive coil is fixed to the skewer base which is a base.
Since the magnetic circuit side formed by the magnet and the yoke is movable, it is possible to further reduce the size and simplify the entire mechanism. Since the drive coil is fixed to the skew base and the leader portion does not move, the reliability of the circuit operation of the feedback system for automatic tracking and automatic focusing can be improved.

Further, since the magnet and the yoke are integrated with the objective lens holding frame, the lead wire of the drive coil is not drawn out from the movable portion unlike the conventional case.
The movable parts are easily integrated, and the manufacturing process is further simplified. Further, it is not necessary to take the space of the leader line in consideration of the movement of the movable part having the mass balance function with respect to the skew base, so that the movable part and the mass balance function part are separated in the tracking direction and the focusing direction. It is possible to further reduce the cost by reducing the restrictions on the design of the holding member that supports the holding member so as to be movable in two directions and the connecting structure with the skewer base that fixes the holding member. Furthermore, assembling the yoke with a separate piece from the objective lens holder may cause partial resonance, so making it a single body is good for the function as an actuator (characteristically), and the number of parts is large. There are advantages such as less.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a lens movable part and a balance movable part of an information detection head driving mechanism in an optical information recording / reading device according to the present invention.

FIG. 2 is a perspective view of a drive coil fixed at a predetermined position with respect to the lens movable portion and the balance movable portion of FIG.

FIG. 3 is a partially cutaway perspective view of a hinge suspension.

FIG. 4 is a plan view of the hinge suspension of FIG.

FIG. 5 is a plan view of the skew base.

FIG. 6 is a rear view of the skew base in which the drive coil is incorporated.

FIG. 7 is a plan view of a hinge suspension in which a lens movable portion and a balance movable portion are coupled to a skew base.

FIG. 8 is a view of the information detection head driving mechanism for the present invention.
It is a schematic diagram for explaining operation in the Casing direction, (a)
Shows a state where the lens is not driven, and (b) shows a state where the lens movable part is moving in the focusing direction by a certain amount.

9A and 9B are schematic diagrams for explaining the operation in the tracking direction of the information detection head drive mechanism according to the present invention, in which FIG. 9A is a state in which the lens is not driven, and FIG. The respective moving states are shown.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Objective lens holder 2 ... Magnet 3 ... Objective lens 4 ... Balance weight 5 ... Balance block 6 and 7 ... Hinge suspension coupling part 8 ... Drive coil 9 ... Focusing coil 10 ... Tracking coil 11 ... Support member 12 ... Lens movable Part connection part 13 ... Hinge suspension (holding member) 14 ... Balance movable part connection part 15 ... Skew base connection part 16, 17 ... Through hole 18, 19 ... Yoke 20, 21, 22, 23 ... Side member 25-38 ... Hinge part 40 ... Skew base 41 ... Balance block accommodating part 42 ... Objective lens holder accommodating part 43, 44 ... Hinge suspension accommodating part 45 ... Hinge suspension fixing part 46 ... Information detecting head drive mechanism fixing hole 50 ... Lens movable part 51 ... Balance movable part (balance block part) 52, 53 ... Hinge suspension Pensions 54 ... skew - base - the scan unit

Claims (1)

[Claims] 1. An apparatus for reading, reproducing, or recording information recorded on a recording medium in a track shape by scanning with a light spot condensed by an objective lens, the information track on the recording medium. And an optical spot for detecting the relative position of the light spot and independently controlling the movement of the position of the objective lens in two directions of a direction perpendicular to the information track and a direction perpendicular to the surface of the information track. In the dynamic information recording / reading apparatus, a lens movable portion in which a magnet is fixed to a yoke function portion formed by designing a function as a yoke of an objective lens holder for holding the objective lens, and the objective lens. The function as a yoke is designed in the balance block that has the same mass as the objective lens holder that holds the Balance block part, a holding member that supports the lens movable part and the balance block part so as to be movable independently of each other in the two directions, and a magnetic member formed by the yoke and the magnet while fixing the holding member. A skew base for fixing the drive coil facing the circuit at a predetermined position, and the drive coil fixed to the skew base and the yaw.
The objective lens holder and the yoke are the same-balanced block and the yoke by the action of electromagnetic force by the magnet.
The optical information recording / reading device is characterized in that the objective lens holder of the same body and the balance block portion of the same body of the yoke are controlled to move independently of each other in the two directions in opposite directions. Information detection head drive mechanism in.