JPS6182339A - Pickup device - Google Patents

Abstract

PURPOSE:To reduce the capacity around the optical axis of a lens by moving a coil for driving in the direction of the optical axis of the lens and a print coil for driving in the direction orthogonal to the optical axis as one body together with the lens and forming an intersecting part where parts of both coils cross each other at about right angles. CONSTITUTION:A lens 12 is attached to a cylindrically flanged lens frame 13, and the lens frame 13 is attached to a magnetic field generating means 16 through springs 14 and dampers 15, and the lens frame 13 can be moved in the direction of the optical axis and the radial direction. A coil bobbin 17 is attached to the lens frame 13, and four print coils 18-21 are provided on the surface of the bobbin 17, and a coil 22 for driving in the direction of the optical axis is wound on coils 18-21. Since a magnetic field going from the outside to the inside is formed in a gap 23 by the magnetic field generating means 16, the bobbin 17 to which the lens 12 is fixed is moved in the direction orthogonal to the optical axis of the lens if a current in a proper direction is flowed to coils 18-21, and the coil bobbin 17 is moved in the direction of the optical axis if a current is flowed to the coil 22.

Description

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

The pickup functions of a player for optically recorded information discs, mainly optical video discs, include focusing, which focuses a read beam on the disc surface, and tracking, which causes the 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 deflect the reading beam incident on the objective lens.

However, in order to keep the galvanomirror from moving at a fairly high speed for tracking, a large amount of force is required.
In addition, the mechanism of the device was large-scale, and the power consumption had to be large.

The present invention is a small and lightweight pickup that solves the above-mentioned drawbacks.
The purpose is to provide (share) the equipment.

That is, the present invention provides a big amplifier 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 of the lens in order to read information recorded on a recording medium. A first coil and a second coil consisting of a printed coil for driving in a direction perpendicular to the optical axis of the lens move together with the lens, and parts of both coils intersect with each other in a state substantially orthogonal to each other. The coil part that
That is, both coils are fixed to the lens so that an intersection is formed, and based on a common magnetic flux penetrating the intersection and energization of both coils, mutual interaction acts on the conductors of both coils at the intersection. The lens is driven in the two-dimensional direction using a force substantially perpendicular to the two-dimensional direction.

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

FIG. 1 is a cross-sectional view of the lens drive mechanism taken along the optical axis.

The lens 12 is attached to a lens frame 13 having a cylindrical shape with a flange, and the lens frame I3 is connected to a magnetic field generating means 16 made of magneto via a bone 14 and a damper 15.
It is taken by 1. The spring I4 is bent in the optical axis direction of the lens 12 and has elasticity in the radial direction of the lens 12, so that the lens frame 13 can move in the optical axis direction as well as in the radial direction.

Further, 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 coil bobbin 17. Figure 2(a) is a perspective view of the coil, Figure 2(b)
is a diagram of the coil viewed from the optical axis direction. As shown in the figure, there are four printed coils 18 to 21 on the surface of the bobbin 17.
has been installed. A coil 22 for driving in the optical axis direction is wound over the coils 18 to 21.

A magnetic field directed from the outside to the inside is generated in the gap 23 by the magnetic field generating means 16 as shown in FIG.
21, the bobbin 17 to which the lens 12 is fixed moves in a direction perpendicular to the optical axis of the lens.
Furthermore, when a current is applied to the coil 22, 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 the ■ mark).

Therefore, the coil conductor vA18-2 is energized from the bottom to the top of the paper (indicated by the ■ mark). At this time, a force A acts on the coil conducting wire 18-1 of the coil 18 in a direction perpendicular to the lens optical axis, that is, approximately in the X-axis direction, according to Fleming's left-hand rule. 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 conductor 2 of the coil 2o facing the coil 18
0-1 is energized from the bottom of the page upwards. Therefore, the tile conducting wire 2o-2 is energized from the top to the bottom of the page.

At this time, a force E in the X-axis direction acts on the coil conductor 20-1, and a force F in the Y-axis direction acts on the coil conductor 20-2.

When the coils 18 and 20 arranged opposite to each other are energized as described above, each coil conductor wire 1B-1, 18-2
, 20-1, 20-2, respectively.
E and F are combined, and the coil bobbin moves in the X-axis direction with an inclination of 45 degrees between the X-axis and the Y-axis, and as a result, the lens 12 moves in a direction perpendicular to the lens optical axis. If this X-axis direction is set to a direction almost perpendicular to the trunk direction, the coil 18
The lens 12 can be driven for trunking by supplying tracking signals to and 20.

On the other hand, the coil 19 is energized from the bottom to the top of the drawing with respect to the coil conducting wire 19-1.

Therefore, the coil conducting wire 19-2 is energized from the top to the bottom of the paper. At this time, a force C in the Y-axis direction acts on the coil conducting wire 19-1, and a force in the opposite direction to the X-axis direction acts on the coil conducting wire 19-2.

Similarly, the coil 21 is energized from the top to the bottom of the paper with respect to the coil conductor 2]-1.

Therefore, a current flows through the coil conducting wire 21-2 from the bottom to the top of the paper. As a result, the coil conductor 21-
A force G in the Y-axis direction acts on the coil conductor 21-2, and a force H in the opposite direction to the X-axis direction acts on the coil conductor 21-2.

As described above, when each coil of coils 19 and 21 is energized in the above direction, forces C and G in the Y-axis direction acting on coil conductors 19-1 and 21-1, respectively, and coil conductors 19-2 The combined force of the force in the direction opposite to the X-axis direction and H acting on the lenses 21-2 and 21-2 moves the lens 12 in the W-axis direction perpendicular to the Z-axis direction. Therefore, if this W-axis direction is set in the information track direction, the lens 12 can be driven in the track direction by flowing the time base collector signal to the coils 19 and 21.

Furthermore, in this embodiment, the lens can be driven in the Y-axis direction in FIG. 3 by sending tracking signals to the four coils 18 to 21 in the aforementioned directions. In this case, the forces E, 1ffl and the coil conductors 18-1 in opposite directions acting on each of the coil conductors 19-2 and 20-1,
Forces A and H in opposite directions acting on lenses 1 and 21-2 cancel each other out, resulting in a force that is unrelated to the movement of lens 12, and force B in the Y-axis direction.

The lens 12 can be moved in the Y-axis direction by the combined force of C, F, and G. If the pickup device is installed so that the Y-axis direction is substantially perpendicular to the information track 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, W-axis direction, or Y-axis direction is possible by uniformly reversing the energization direction.

As described above, the present invention moves the coil for driving the lens in the optical axis direction (first coil) and the Prin I coil for driving in the direction perpendicular to the lens optical axis (second coil) integrally with the lens. At the same time, both coils are arranged so that a coil part (crossing part) is formed where a part of both coils intersect with each other in a substantially orthogonal state, and a common magnetic flux is passed through this crossing part. When the lens is removed, 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 using the mutually orthogonal forces that act on both coils at the intersection when energized. The characteristic configuration is that a common magnetic flux passes through the intersection.

With such a configuration, the pick amplifier device of the present invention has the effect that the volume around the lens optical axis can be reduced, and as a result, the pickup device can be significantly downsized.

Furthermore, since a printing coil is used as the second coil, the production of the pickup is significantly facilitated.

Note that the present invention is not limited to the above-mentioned embodiments,
It goes without saying that the present invention can be used not only for video disk playback devices but also for example for disk playback devices on which music information is recorded.

[Brief explanation of drawings]

Fig. 1 is a line diagram showing an example of a mechanism for moving the lens in each direction, Fig. 2 (a) and (b) are a perspective view of the coil without moving the lens in each direction, and a line diagram seen from the optical axis direction; FIG. 3 shows a cross-sectional view of the lens drive mechanism perpendicular to the optical axis.

Claims (1)

[Scope of Claims] In a pickup device that drives a lens in a two-dimensional direction in the optical axis direction of the lens and in a direction perpendicular to the optical axis direction of the lens in order to read information recorded on a recording medium, a pickup device for driving the lens in the optical axis direction A first coil and a second coil consisting of a printed coil for driving in a direction perpendicular to the optical axis of the lens move together with the lens, and parts of both coils intersect with each other in a state substantially orthogonal to each other. The coil part that
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, a mutual effect that acts on the conductors of both coils at the intersection is generated. A pickup device that drives the lens in the two-dimensional direction using substantially orthogonal forces.