JPH01173331A - Tracking control structure for optical card - Google Patents

Abstract

PURPOSE:To suppress the adjusting width of tracking adjustment to be small by always holding the scanning direction of an optical card and the direction of a track to be parallel with an angle correcting means. CONSTITUTION:A motor 15 is driven and a carriage 12 is displaced in an x- direction. Then, the scanning of an optical head 32 is executed to an optical card 1. Simultaneously, based on a prescribed tracking control principle, a tracking control mechanism 32a is driven and necessary tracking operation is executed. During the operation, displacement quantity DELTAx in the x-direction and displacement quantity DELTAy in a tracking direction are inputted to a CPU34 and a deviation angle theta is obtained based on a correcting table 39. Next, by exciting a solenoid 30, a pressing board 23 is caused to rise up through a cam- follower 26 and a turn table 17 is made free. Then, a motor 21 is driven in order to revolve the turn table 17 by the necessary angle theta. Thus, the control is executed so that the deviation angle goes to be zero and an over burden is removed to a tracking actuator 32.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a structure for suitably controlling the tracking of an optical head on a recording medium having a linear track, such as an optical card.

<Prior Art> Conventionally, various tracking control structures have been used to make an optical head follow a track provided on the side of a recording medium. The required tracking adjustment is performed by relatively scanning the optical head along the scanning direction and adjusting the position of the optical head in a direction perpendicular to the scanning direction. However, for recording media with linear tracks such as optical cards, the amount of control when performing tracking control tends to be large due to manufacturing errors and distortions of the optical card itself. When attempting to increase the access speed due to the increased burden on the structured recording medium, there is a problem in that the followability of the optical head tends to be insufficient, making it impossible to increase the access speed.

However, the inventors have found that the amount of tracking control tends to increase because the scanning direction of the optical head with respect to the optical card is not necessarily parallel to the tracks of the optical card.

<Problems to be solved by the invention> In view of the problems of the prior art and the inventor's knowledge,
A main object of the present invention is to provide a tracking control structure with excellent followability in a device that accesses a recording medium such as an optical card.

<Means for Solving the Problems> According to the present invention, an object of the present invention is to provide a tracking control structure in an apparatus for reading from or writing to an optical card, in which the optical head is connected to the optical card. means for relatively scanning in a direction along a track of the optical card; means for adjusting tracking of the optical head in a direction perpendicular to the scanning direction with respect to the track of the optical card; This is achieved by providing a tracking control structure for an optical card characterized by comprising means for correcting the angle with respect to the direction.

Effect> Since the scanning direction and the track direction can always be kept parallel to each other by the angle correction means, it is possible to keep the adjustment range of tracking adjustment small.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an optical card 1 to which the present invention is applied.
A plurality of rows of tracks 3 that are parallel to each other are formed in a part of the area 2 . Along this track 3 (X direction) or by switching track 3 (X direction)
, exchanges information with truck 3.

Figure 2 shows the track 3 and optical head light beams 4a and 4b.
Δx=x2−xl along the X direction while the light beams 4a and 4b are scanned from point A to B.
During the displacement, the light beam also moves in the X direction Δ'! ='12
−yl displacement, i.e. with respect to the scanning direction 6, the light beam 4a,
The locus 5 of 4b forms an angle θ. Therefore, as the light beam is scanned in the X direction, the displacement in the X direction, that is, the tracking error increases proportionally. Furthermore, as the scanning speed of the light beam in the X direction increases, the displacement speed in the X direction, that is, the increasing speed of tracking error increases proportionally, and a high response speed is required for the tracking control structure of the optical head. Become so.

3 and 4 show an embodiment of an optical card access device to which an optical card tracking control structure constructed based on the present invention is applied in order to cope with such problems.

A carriage 12 is supported for linear movement along a pair of parallel rails 11. A threaded rod 14 driven by a motor 15 and supported by a bearing 13 is screwed into a nut 12a fixed to the carriage 12, and by rotating the motor 15 forward and backward, the carriage 1 is rotated.
2 can be moved along the axial direction of the rail 11.

A rotary encoder 16 is attached to the motor 15 for providing information corresponding to the position of the carriage 12 in the X direction.

A turntable 17 is supported on the upper surface of the carriage 12 so as to be rotatable about a vertical rotational axis 18, and a recess 19 provided in the center of the turntable 17 is supported.
An optical card 1 is placed inside. turntable 17
An arcuate end face 20 is formed on one side, and this arcuate end face 20 frictionally engages with a rubber roller 22 attached to an output shaft of a motor 21 fixed to the carriage 12 or other fixed part. is engaged in.

Guide blocks 25 are protruded from the left and right sides of the carriage 12, and a pair of guide holes formed vertically in each of these guide blocks 25 have guide holes fixed integrally with the presser plate 23. A rod 24 penetrates from above, and a cam follower 26 is fixed to its protruding lower end. A compression coil spring 27 is wound around the outer periphery of the guide rod 24 between the cam follower 26 and the guide block 25, and constantly urges the presser plate 23 downward. Directly below the carriage 12, a pair of levers 29 are supported so as to be able to rotate up and down on pivot shafts 28, and one end 29b of these levers 29 is connected to a plunger of a solenoid 30 via a common pivot. 31, and the other ends of these levers 29 forming cam surfaces 29a are adapted to come into contact with the cam followers 26, respectively.

An optical head 32 is disposed directly above the optical card 1, and the optical head is provided with a tracking control mechanism 32a. Further, a control unit 33 for controlling each of the above-mentioned parts includes a rotary encoder 16, a solenoid 30, a motor 21, and a tracking control mechanism 32.
connected to a.

FIG. 4 specifically shows the structure of the control unit 33, which includes a CPU 34 consisting of a microprocessor or the like. The displacement amount ΔX in the scanning direction is input from the rotary encoder 16 to the CPU 34, and the tracking driver 3
Tracking control mechanism 32 of optical head 32 via 5
When the signal sent for a is digitized by the AD converter 36, the displacement Δy in the racking direction becomes CP
It is input to U34. By applying these ΔX and Δy to the three correction tables, the CPU 34 calculates the angular deviation θ. This angular deviation θ is tanθ
It may be given as -Δy/ΔX. C.P.
U34 also drives solenoid 30 and motor 21 via drivers 37,38.

Next, the operation of this embodiment will be explained.

First, by driving the motor 15, the carriage 12
is displaced in the X direction, and the optical head 3 is moved relative to the optical card 1.
Perform 2 scans. At the same time, the tracking control mechanism 32a is driven to perform a required tracking operation based on a predetermined tracking control principle. Meanwhile, the amount of displacement Δ in the X direction
The amount of displacement Δy in the X and trunking directions is CP, respectively.
The deviation angle θ is input to U34 and based on the correction table 39.
is required. Next, by energizing the solenoid 30, the presser plate 23 is raised via the cam follower 26, thereby freeing the turntable 17, and in order to rotate the turntable 17 by a required angle θ, the motor 2
Drive 1. In this way, it is possible to control the deviation angle θ to be 0, thereby eliminating an excessive burden on the tracking actuator 32a.

<Effects of the Invention> According to the present invention, it is possible to increase the tolerance for card manufacturing errors or scanning v1 mechanism operation errors, and the burden on the tracking actuator or tracking control mechanism can be reduced. , the manufacturing cost of the card or the tracking control mechanism can be reduced. Moreover, the access speed is increased, and the reliability of tracking control can be further improved.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an optical card to which the present invention is applied. FIG. 2 is an explanatory diagram for explaining the operating principle of the present invention. FIG. 3 is an exploded perspective view showing one embodiment of the tracking control mechanism based on the present invention. FIG. 4 is a block diagram specifically showing the configuration of the control unit. 1... Optical card 2... Area 3... Track 4a, 4b... Light beam 5... Trajectory
6...Scanning direction 10...Optical card access device 11...Rail 12...Carriage 12a
... Nut 13 ... Bearing 14 ... Threaded rod
15...Motor 16...Rotary encoder 17...Turntable 18...Rotation axis 19...
- Concave portion 20... Arc-shaped end surface 21... Motor 22... Roller 23... Holding plate
24... Guide rod 25... Guide block 26
...Cam follower 27...Compression coil spring 28...
・Pivot 29...Lever 29a...Cam surface 2
9b...One end 30...Solenoid 31...
・Plunger 32...Optical head 32a...Tracking control mechanism

Claims (2)

[Claims] (1) A tracking control structure in a device for reading from or writing to an optical card, comprising means for relatively scanning an optical head in a direction along a track of the optical card; A tracking control for an optical card, comprising: means for adjusting the tracking of the track of the optical card in a direction perpendicular to the scanning direction; and means for adjusting the angle of the scanning direction with respect to the direction of the track. structure. (2) The scanning means has a carriage that carries the optical card, the tracking adjustment means has a tracking adjustment mechanism provided on the optical head, and the angle correction means is on the carriage. The optical card tracking control structure according to claim 1, further comprising a turntable that supports the optical card.