JPH03122831A - Optical pickup - Google Patents

Abstract

PURPOSE:To shorten time until the track servo of an access end is made stable when the high-speed access is performed by providing a mechanism to engage a linking member when the track servo is turned OFF. CONSTITUTION:The mechanism is provided to engage the linking member when the track servo is turned OFF. Namely, when a track servo signal is turned OFF, a switch 55 reacts and is closed and piezoelectric elements 53 and 54 are deformed. Then, a linking member 45 is engaged by being pressed. By the engagement of this linking member 45, the deformation of a track leaf spring 43 is inhibited and the movement of a lens holder in a track direction is inhibited. Thus, with simple construction and further even if the high-speed access is performed, the time can be shortened until the track servo is made stable after the end of the access.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention comprises a set of track leaf springs whose proximal ends are attached to the base side and are flexible in the tracking direction; It has a connecting member that connects the distal ends, a pair of focus plate springs having a proximal end attached to the connecting member, a distal end attached to the lens holder, and flexible in the focusing direction, and a track servo on/off switch. This invention relates to an optical pickup that turns on/off a track servo using a signal.

(Background of the Invention) Next, a conventional example will be explained using the drawings. Fig. 4 is a plan view illustrating the main parts of a conventional optical pickup, and Fig. 5 is a plan view illustrating the main parts of a conventional optical pickup.
It is a front view in a figure.

In these figures, reference numeral 1 denotes a base of an optical pickup that is movable in the radial direction (track direction) of a recording medium (not shown) and driven by a drive source (for example, a linear motor) (not shown). In this base 1,
Center yoke portion 2a.

A substantially square-shaped first yoke 2 consisting of side yoke portions 2b and 2c is attached. Further, in parallel with this first yoke 2, a center yoke portion 3a.

A substantially V-shaped second yoke 3 consisting of side yoke portions 3b and 3c is attached.

Side yoke portions 2 of these first and second yokes 2 and 3
Magnet 4.5, 6.7 for b, 2c, 3b, 3c
are attached to each.

By attaching these magnets 4 to 7, a magnetic circuit is formed in the first yoke 2 and the second yoke 3.

A lens holder 8 holds an objective lens 9 that focuses a laser beam onto a recording medium. This lens holder 8
Holes 8a and 8b are formed on both sides. Further, a focus coil 10 is wound around the circumferential surface of the lens holder 8. The lens holder 8 has a center yoke portion 2a of the first yoke 2 loosely fitted into the hole 8a, and a hole 8b.
The center yoke portion 3a of the second yoke 3 is disposed so as to loosely fit therein.

11 and 12 are support columns provided on the base 1. 1
Reference numeral 3.14 designates a pair of track leaf springs whose proximal ends are attached to the base side and are flexible in the tracking direction, and reference numeral 15 designates a connecting member that connects the tip ends of the pair of track leaf springs 13 and 14. Reference numerals 16 and 17 designate a pair of focus leaf springs whose base ends are attached to the connecting member 15 and whose distal ends are attached to the lens holder 8, and which are flexible in the focusing direction.

Further, four track coils 18, 19, 20, and 21 are attached to the corners of the focus coil 10.

Next, the operation of the above configuration will be explained. First, focusing will be explained. The focus servo is controlled (on/off) by the focus servo on/off signal. When the focus servo is turned on and the focus control circuit supplies current to the focusing coil 10, an electromagnetic force is generated in the focus coil 10 that moves the lens holder 8 in the focus direction.
The lens holder 8 moves in the focusing direction against the urging force of the focus plate springs 16 and 17, and focusing is performed. Then, when the supply of current is stopped, the lens holder 8 returns to its original position due to the biasing force of the focus plate springs 16 and 17.

Next, tracking will be explained. This tracking is also controlled (on/off) of the track servo by the track servo on/off signal. Then, when the track servo is turned on and the tracking control circuit supplies current to the track coils 18, 19, 20, and 21, the track coils 18, 19, and 20.
An electromagnetic force is generated to move the lens holder 8 in the track direction, and the lens holder 8 moves in the track direction against the urging force of the track plate springs 13 and 14, thereby performing tracking. Then, when the supply of current is stopped, the lens holder 8 returns to its original position due to the biasing force of the track leaf springs 13 and 14.

Finally, during so-called access servo, which displaces the entire optical pickup in the radial direction (track direction) of the recording medium, an access control circuit (not shown) is provided on the base 1 or drives a near motor to move the entire optical pickup to the desired location on the recording medium. move it onto the track.

(Problems to be Solved by the Invention) In the conventional example with the above configuration, when the access servo is operating, the track servo signal is off, and the track servo is not operating. For this reason, for example, the sixth
As shown in the figure and FIG. 7, when the optical pickup accesses in the direction of arrow 1 or the direction of arrow 2, the lens holder 8 moves due to inertia and is deviated from the optical axis. Therefore, there is a problem in that it takes time for the track servo to stabilize when the track servo signal is turned on after access is completed. The higher the speed of access, the greater the optical axis deviation, and the longer it takes for the track servo to stabilize.

In addition, in order to solve such problems, the objective lens 9
There is also a type of optical pickup that is equipped with a sensor that detects the position of the (lens holder 8) and applies a servo so that the objective lens 9 always aligns with the optical axis during access (when the track servo signal is off). be. There is also an optical pickup in which the position of the objective lens 9 is detected using a low frequency component of a track error signal without providing a special sensor.

However, such an optical pickup requires a servo that can counteract the acceleration during access, resulting in problems such as an increase in the size of the optical pickup and a slow access time.

The present invention has been made in view of the above-mentioned problems, and its purpose is to have a simple configuration, and even with high-speed access.
To provide an optical pickup that takes a short time to stabilize a track servo after access is completed.

(Means for Solving the Problems) The present invention to solve the above problems includes a set of track leaf springs whose proximal ends are attached to the base side and are flexible in the tracking direction; It has a connecting member that connects the distal ends, a pair of focus plate springs having a proximal end attached to the connecting member, a distal end attached to the lens holder, and flexible in the focusing direction, and a track servo on/off switch. An optical pickup in which a track servo is turned on and off by a signal is provided with a mechanism for locking the connecting member when the track servo is turned off.

(Function) In the optical pickup of the present invention, when the track servo is off, the connecting member is locked by the mechanism that locks the connecting member, and the lens holder is prohibited from moving in the track direction.

(Example) Next, one embodiment of the present invention will be described using the drawings.

FIG. 1 is a front view illustrating the main parts of an optical pickup according to a first embodiment of the present invention, FIG. 2 is a plan view of FIG. 1,
FIG. 3 is a configuration diagram illustrating the second embodiment.

First, a first embodiment will be described using FIGS. 1 and 2. In these figures, 31 is provided movably in the radial direction (track direction) of a recording medium (not shown),
This is the base of an optical pickup driven by a drive source (for example, a linear motor) not shown. This base 3
1 includes a center yoke portion 32a and a side yoke portion 32b.
, 32c is attached to the first yoke 32 having a substantially square shape. Also, in parallel with this first yoke 32, a center yoke portion 33a, side yoke portions 33b, 33
A second yoke 33 having a substantially Y-shape is attached.

The side yoke parts 32b, 32c, 33b, 33c of these first and second yokes 32.33 have magnets 3
4, 35, 36.3.7 are attached respectively. By attaching these magnets 34 to 37, a magnetic circuit is formed in the eleventh yoke 32 and the second yoke 33.

38 is a lens holder that holds an objective lens 39 that focuses a laser beam onto a recording medium.

This lens holder 38 has holes 38a on both sides.

38b is formed. Furthermore, a focus coil 40 is wound around the circumferential surface of the lens holder 38. The lens holder 38 has the first yoke 32 in the hole 38a.
The center yoke portion 32a of the second yoke 33 is loosely fitted into the hole 38b, and the center yoke portion 33a of the second yoke 33 is loosely fitted into the hole 38b.

41 and 42 are support columns provided on the base 31.

Reference numerals 43 and 44 designate a pair of track leaf springs whose proximal ends are attached to the base side and are flexible in the tracking direction, and 45 represents a connecting member that connects the distal ends of the pair of track leaf springs 43 and 44. Reference numerals 46 and 47 designate a pair of focus leaf springs whose base ends are attached to the connecting member 45 and whose distal ends are attached to the lens holder 38, and which are flexible in the focusing direction.

Furthermore, four track coils 48, 49, 50, and 51 are attached to the corners of the focus coil 40.

52 is a piezoelectric element support column provided on the base 31, 53
．． A piezoelectric element 54 is attached to the piezoelectric element support column 52 and bends so as to press the connecting member 45 when a voltage is applied.

55 is a switch that closes in response to an off signal of the track servo on/off signal, and 56 is a power source.

Next, the operation of the above configuration will be explained. First, focusing will be explained. The focus servo is controlled (on/off) by the focus servo on/off signal. Then, when the focus servo is turned on and the focus control circuit supplies current to the focusing coil 40, an electromagnetic force is generated in the focus coil 40 that moves the lens holder 38 in the focus direction, and the lens holder 38 is moved by the focus leaf spring. Focusing is performed by moving in the focus direction against the urging force of 46 and 47. Then, when the current supply is stopped, the biasing force of the focus leaf springs 46 and 47 causes the lens holder 3 to
8 returns to the original position.

Next, tracking will be explained. This tracking is also controlled (on/off) of the track servo by the track servo on/off signal. Then, when the track servo is turned on and the tracking control circuit supplies current to the track coils 48, 49, 50, and 51, the track coils 48, 49, and 50,
An electromagnetic force is generated that moves the lens holder 38 in the track direction, and the lens holder 38 is moved by the track leaf springs 43 and 44.
Tracking is performed by moving in the track direction against the urging force of . Then, when the supply of current is stopped, the lens holder 38 is
returns to its original position.

Finally, during so-called access servo, which displaces the entire optical pickup in the radial direction (track direction) of the recording medium, an access control circuit (not shown) is provided on the base 31 or drives a near motor to move the entire optical pickup to the desired location on the recording medium. move it onto the track. At this time, the track servo signal is off. Therefore, the switch 55 closes in response, the piezoelectric elements 53 and 54 are deformed as shown by the two-dot chain line in FIG. 1, and the connecting member 45 is pressed and locked. This locking of the connecting member 45 prevents the track leaf springs 43 and 44 from deforming.
Movement of the lens holder 38 in the track direction is prohibited.

According to the above configuration, even if the optical pickup performs high-speed access, the lens holder 38 is prohibited from moving in the track direction, so even if the track servo is applied after access is completed, the lens holder stabilizes in a short time. Furthermore, the configuration is simple.

Furthermore, since the lens holder 38 is prohibited from moving in the track direction during access, damage to the optical pickup can be reduced even if a sudden shock is applied to the optical pickup from the outside.

Next, a second embodiment of the present invention will be described using FIG. In this embodiment, the same parts as those in the first embodiment are given the same reference numerals, and their explanation will be omitted.

In the figure, 61 and 62 are rotatably provided on the support column 63, and have first and second ends that can hold the connecting member 45 at one end.
This is a holding member. At the other ends of these clamping members 61.62, in a direction opposite to the clamping direction of the clamping members 61.62,
A spring 63 is provided to bias the holding member 6162. An electromagnet 64 is provided at the other end of the second holding member and is activated when the track servo on/off signal is turned off. 65 is a ferromagnetic material provided at the other end of the first holding member.

Next, the operation of the above configuration will be explained. When the track servo on/off signal is on, the electromagnet 64 is not activated, and the urging force of the spring 63 releases the connection member 45 from being held by the first and second holding members 61 and 62. Next, when the track servo on/off signal is off,
The electromagnet 64 is activated, and the first and second clamping members 61 and 62 clamp the connecting member 45 against the biasing force of the spring 63, and the connecting member 45 is locked. In this embodiment as well, the same effects as in the first embodiment can be obtained.

(Effects of the Invention) As described above, according to the present invention, by providing a mechanism for locking the connecting member when the track servo is turned off,
It is possible to realize an optical pickup with a simple configuration, and moreover, even when high-speed access is performed, it takes a short time for the track servo to stabilize after the access is completed.

[Brief explanation of drawings]

FIG. 1 is a front view illustrating the main parts of an optical pickup according to a first embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a configuration diagram illustrating a second embodiment. Figure 4 is a plan view explaining the main parts of a conventional optical pickup, Figure 5 is a front view of Figure 4, Figure 6 is a diagram explaining the problem, and Figure 7 is a diagram explaining the problem. be. In these figures, 1.31...Base 13.14, 33.34...Track leaf spring 15.3
5... Connecting member 16.17, 369.37... Focus leaf spring complementary color 6 Fig. 7 Fig. 15 Connection member

Claims (1)

[Scope of Claims] A set of track leaf springs (43, 44) whose proximal ends are attached to the base (31) side and are flexible in the tracking direction; and the set of track leaf springs (43, 44). a connecting member (45) that connects the distal ends of the connecting member (45); a pair of focus plates that are flexible in the focusing direction, the proximal end of which is attached to the connecting member (45), the distal end of which is attached to the lens holder (38); Spring (46, 47)
What is claimed is: 1. An optical pickup that turns on/off a track servo using a track servo on/off signal, characterized in that the optical pickup is provided with a mechanism for locking the connecting member (45) when the track servo is turned off.