JPS6118261B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the pickup of an optically recorded disc, primarily a video disc player.

The pick-up functions of a player for a disc that optically records information, mainly an optical video disc, include focusing, which focuses a read beam on the disc surface, and tracking, which causes a read beam to follow an information track. Conventionally, focusing was performed by moving the objective lens in the optical axis direction, and tracking was performed by moving a galvanometer mirror to tilt the reading beam incident on the objective lens.

However, in order to move the galvano mirror at a fairly high speed for tracking, a large amount of force is required, and the mechanism of the device becomes large-scale, which inevitably consumes a large amount of power.

SUMMARY OF THE INVENTION An object of the present invention is to provide a small and lightweight pickup device that solves the above-mentioned drawbacks.

The present invention provides a pickup device for driving a lens in the optical axis direction of the lens and in a two-dimensional direction perpendicular to the optical axis direction in order to read information recorded on a recording medium. A coil portion in which a first coil and a second coil for driving in a direction perpendicular to the lens optical axis direction move integrally with the lens, and a portion of both coils intersect with each other in a substantially orthogonal state. That is, both coils are fixed to the lens so that an intersection is formed, and based on a common magnetic flux passing through the intersection and energization of both coils, it acts on the conductors of both coils at the intersection. The lens is driven in the two-dimensional direction using forces that are substantially orthogonal to each other.

A feature of the present invention is that by passing a common magnetic flux through the intersection, the lenses are driven in two-dimensional directions using forces acting on the coils at the intersection that are substantially perpendicular to each other.

The present invention will be explained in detail below based on the drawings.

FIG. 1 is a cross-sectional view of the lens drive mechanism along the optical axis. The lens 12 is attached to a cylindrical lens frame 13 with a flange.
3 is attached via a spring 14 and a damper 15 to a magnetic field generating means 16 consisting of a magnet. The spring 14 bends in the optical axis direction of the lens 12,
The lens 12 is also stretchable in the radial direction, and therefore the lens frame 13 can move in the optical axis direction as well as in the radial direction.

Furthermore, a coil bobbin 17 is attached to the lens frame 13, and a coil having the structure shown in FIG. 2 is formed on this. FIG. 2a is a perspective view of the coil, and FIG. 2b is a view of the coil viewed from the optical axis direction. As shown in the figure, the surface of the bobbin 17 has four coils 18 to 18, which can be printed coils.
21 are provided, and these coils 1
A coil 22 for driving in the optical axis direction is wound on top of the elements 8 to 21.

A magnetic field directed from the outside to the inside is formed in the gap 23 by the magnetic field generating means 16 as shown in FIG. A bobbin 17 to which the lens 12 is fixed by passing a current in an appropriate direction
moves in a direction perpendicular to the lens optical axis, and coil 2
When a current is passed through the coil bobbin 17, the coil bobbin 17 moves in the optical axis direction.

An example of energizing the coils 18 to 21 will be described below.

The coil conducting wire 18-1 of the coil 18 is energized from the top to the bottom of the paper (indicated by a circle).

Therefore, the coil conducting wire 18-2 is energized from the bottom to the top of the paper (indicated by a circle). At this time,
The coil conductor 18-1 of the coil 18 has a direction perpendicular to the lens optical axis according to Fleming's left hand rule,
That is, force A acts approximately in the X-axis direction. On the other hand, a force B approximately in the Y-axis direction similarly acts on the coil conducting wire 18-2.

On the other hand, the coil conducting wire 20-1 of the coil 20 facing the coil 18 is energized from the bottom to the top of the paper. Therefore, the coil conducting wire 20-2 is energized from the top to the bottom of the page. At this time, a force E in the X-axis direction is applied to the coil conductor 20-1, and a force F in the Y-axis direction is applied to the coil conductor 20-2.

Coils 18 and 2 are arranged facing each other as described above.
0 is energized as described above, each coil conductor 18
The forces A, B, E, and F acting on -1, 18-2, 20-1, and 20-2 are combined, and the coil bobbin moves in the Z-axis direction with an inclination of 45 degrees to the X-axis and Y-axis. , as a result, the lens 12 moves in a direction perpendicular to the lens optical axis.

If this Z-axis direction is set to be substantially perpendicular to the tracking direction, the lens 12 can be driven for tracking by supplying tracking signals to the coils 18 and 20.

On the other hand, regarding the coil 19, the coil conductor 19-
Regarding 1, energize from the bottom of the page to the top. Therefore, the coil conducting wire 19-2 is energized from top to bottom in the drawing. At this time, the coil conductor 19
-1 has a force C in the Y-axis direction, and the coil conductor 19-2
A force D in the X-axis direction and the opposite direction acts on each of them.

Similarly, regarding the coil 21, the coil conductor 21-
Regarding 1, the current is applied from the top to the bottom of the page. Therefore, a current flows through the coil conducting wire 21-2 from the bottom to the top of the page. As a result, a force G in the Y-axis direction is applied to the coil conductor 21-1.
A force H in a direction opposite to the X-axis direction acts on -2.

When the coils 19 and 21 are energized in the above direction, the coil conductors 19-1 and 21
-1 in the Y-axis direction, and forces D and H in the opposite direction to the X-axis direction, acting on the coil conductors 19-2 and 21-2, respectively.
The resultant force moves the lens 12 in the W-axis direction perpendicular to the Z-axis direction. Therefore, if the W-axis direction is set substantially in the track direction, the lens 12 can be moved in the track direction by passing the time base collector signal to the coils 19 and 21.

Further, in this embodiment, the lens can be moved in the Y-axis direction in FIG. 3 by sending a tracking signal to the coils 18 to 21 in the above-mentioned direction. In this case, coil conductors 19-2 and 20-
The forces D and E in opposite directions acting on each of the coil conductors 18-1 and 21-2 and the forces A and H in opposite directions acting on each of the coil conductors 18-1 and 21-2 cancel each other out, resulting in the movement of the lens 12. are unrelated forces, and the lens 12 can be moved in the Y-axis direction by the combined force of the forces B, C, F, and G in the Y-axis direction. If the pickup device is installed so that the Y-axis direction is substantially perpendicular to the information tracking direction of the disk, the lens 12 can be driven for tracking.

In the above description, it is clear that movement in the opposite direction with respect to the Z-axis direction and the W-axis direction or the Y-axis direction is possible by uniformly reversing the energization direction.

As described above, the present invention moves the coil for driving the lens optical axis direction (first coil) and the driving coil in the direction perpendicular to the lens optical axis direction (second coil) integrally with the lens. At the same time, both coils were arranged so that a part of both coils intersected each other in a state of almost perpendicularity (crossing part), and a common magnetic flux was passed through this crossing part. The lens is driven in the two-dimensional direction of the lens optical axis direction and the direction perpendicular to the lens optical axis direction by using mutually orthogonal forces that act on both coils at the intersection when electricity is applied. , its characteristic structure is that the first and second coils are fixed to the lens so as to move integrally with the lens, and a common magnetic flux is passed through the intersection.

With such a configuration, the magnetic field generating means of the present invention is extremely simple and compact, and as a result, the pickup device can be made compact.

It should be noted that the present invention is not limited to the above-described embodiments, and can of course be used not only for video disc playback devices but also for example for disc playback devices on which music information is recorded.

[Brief explanation of the drawing]

Figure 1 is a diagram showing an example of a mechanism for moving the lens in each direction, Figures 2 a and b are perspective views and diagrams of the coil that moves the lens in each direction, and diagrams seen from the optical axis direction, Figure 3 is the lens FIG. 4 shows a cross-sectional view perpendicular to the optical axis of the drive mechanism. 12...lens, 13...lens frame, 14...
Spring, 15... Damper, 16... Magnetic field generating means, 17... Coil bobbin, 18-21... Coil, 22... Coil, 23... Gap, 18-
1, 18-2, 19-1, 19-2, 20-1,
20-2, 21-1, 21-2...Coil conductor wire.

Claims (1)

[Claims] 1. In a pick-up device that drives a lens in a two-dimensional direction in the direction of the optical axis of the lens and in a direction perpendicular to the direction of the optical axis of the lens in order to read information recorded on a recording medium, the optical axis of the lens is A first coil for directional driving and a second coil for driving in a direction perpendicular to the lens optical axis direction move integrally with the lens, and parts of both coils are substantially orthogonal to each other. Both coils are fixed to the lens so that an intersecting coil portion, that is, an intersection is formed, and based on the common magnetic flux passing through the intersection and the energization of both coils, the coils at the intersection are A pickup device that drives the lens in the two-dimensional direction using forces acting on conductive wires that are substantially orthogonal to each other.