JPH03280225A - Objective lens drive device - Google Patents

Abstract

PURPOSE:To easily attain positioning at the time of fixing a driving coil on a lens holder, to remove the probability of contact between the driving coil and an inner york and to prevent the coil from being disconnected by forming a projected shape on the inside of a hollow part penetrated through a lens holder. CONSTITUTION:An objective lens 21 is fixed to the lens holder 22 and a focus coil 23 and a tracking coil 24 stuck and united with each other are fixed on the hollow part of the lens holder 22. The projected part 22a extruded around the coil 23 is formed on the inside of the hollow part of the lens holder 22, and at the time of fixing the coils 23, 24 on the lens holder 22, their positioning is executed by using the protected part 22a as a stopper. When the lens holder 22 is moved in the vertical direction Y to the optical axis, the projected part 22a is used as the stopper of the inner york 27a and prevents the coil 23 from being touched with the york 27a, so that the coil 23 is not disconnected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an objective lens driving device that forms part of an optical pickup that projects a light spot onto a disk to perform recording and reproduction.

BACKGROUND OF THE INVENTION FIG. 6 is an exploded perspective view showing the structure of a conventional objective lens driving device. The objective lens 1 is fixed to a lens holder 2, and a focusing coil 3 and a tracking coil 4, which are bonded and integrated, are fixed to a through-hole of the lens holder 2.

The four wires 6 arranged in parallel have both ends soldered to a base board 9 fixed to the base 6 and a holder board 10 fixed to the lens holder 2, respectively.

Thereby, the lens holder 2 is supported in a cantilevered manner. A magnet 8 is fixed to the yoke 7, and this yoke 7
The base 5, which is a fixing member, is attached to the yoke 7, and the inner yoke T& provided on the yoke 7 enters the focus coil lv3 with a gap. As a result, the focus coil 1 attached to the lens holder 2 is inserted into the magnetic gap formed between the magnet 8 and the inner yoke 7a.
0 and a part of the tracking coil 11 are inserted. The center axis of the focus coil 3 is aligned with the objective lens 10.
The lens holder 2 is wound parallel to the optical axis, and when a current flows through it, the lens holder 2 moves in the optical axis direction (two directions in the figure). In addition, the tracking coil Iv4 is wound as an effective part in the magnetic gap so that a current flows in the optical axis direction, and when the current flows, the lens holder 2 moves in a direction perpendicular to the optical axis (Y direction in the figure). Moving. As described above, the objective lens driving device drives the objective lens two-dimensionally in the optical axis direction and in the direction perpendicular to the optical axis direction by passing current through both coils.

FIG. 6 is an exploded perspective view of the focusing coil 3, tracking coil 4, and lens holder 2 in the conventional example shown in FIG. The tracking coil 4 is bonded to the outer peripheral surface of the focus coil 3, and the focus coil 3 and the tracking coil 4 are fixed to the inner surface of the hollow penetrating portion of the lens holder 2.

Problems to be Solved by the Invention However, in the above conventional configuration, the focus coil 3
When fixing the tracking coil 4 (hereinafter referred to as the drive coil) to the lens holder 2, it is difficult to position the through-hole of the lens holder 2 in the penetrating direction, and the contact between the liquid adhesive and the lens holder 2 and the drive coil may be difficult. There is a problem in that the movable range of the lens holder 2 becomes narrow due to the protrusion out of the plane. Furthermore, FIG. 7 is a plan view showing the configuration of parts inside the lens holder of this conventional example.
When the lens holder 2 moves in the direction perpendicular to the optical axis (the Y direction in the figure), the focus coil 3 surrounds the inner yoke 7a.
However, due to frequent contact with the inner yoke 7a, a serious problem arises in that the focus coil 3 is disconnected.

Means for Solving the Problems In order to solve the above problems, the objective lens driving device of the present invention provides a convex shape on the inner surface of the hollow portion through which the lens holder passes, positions the focusing coil and the tracking coil, and uses an adhesive to position the focusing coil and the tracking coil. This convex portion restricts the movable range of the lens holder in the direction perpendicular to the optical axis, thereby preventing contact between the focusing coil and the inner yoke.

Function: By providing a convex shape on the inner surface of the hollow portion through which the lens holder passes, the present invention enables easy positioning when fixing the driving coil to the lens holder, prevents adhesive from flowing out, This convex part restricts the range of movement of the lens holder in the direction perpendicular to the optical axis, eliminating the possibility of contact between the inside of the drive coil and the yoke and preventing the drive coil from breaking. Assembling workability and reliability can be improved.

EXAMPLE Hereinafter, an objective lens driving device of the present invention will be explained with reference to the drawings.

A first embodiment of the present invention will be described using FIG. 1, FIG. 2, and FIG. 3. FIG. 1 is an exploded perspective view showing the configuration of an objective lens driving device of the present invention.

The objective lens 21 is fixed to a lens holder 22, and a focusing coil 23 and a tracking coil/v24, which are bonded and integrated, are fixed to the hollow part of the lens holder 22. The four parallel wires 26 are soldered at both ends to a base substrate 29 fixed to the base 25 and to a holder substrate 3o fixed to the lens holder 22, respectively. Thereby, the lens holder 22 is supported in a cantilevered manner. A magnet 28 is fixed to a yoke 27, the base 25, which is a fixing member, is attached to the yoke 27, and an inner yoke 27a provided on the yoke 26 is inserted into the focus coil 23 with a gap. . FIG. 2 is a diagram showing details of fixing the focusing coil 23 and tracking coil/l/24 to the lens holder 22 in this embodiment. The tracking coil 24 is glued to the outer peripheral surface of the focus coil 1V23.

This focus carp) v23 and tracking carp/L
/24 is the inner surface of the hollow part of the lens holder 22, and the convex portion 22 protruded from this inner surface to the periphery of the focus coil /1/23 with a slight margin of the thickness of the focus coil 23.
The position is determined by relying on point a.

Furthermore, after positioning, the adhesive is applied from the gap between the contact surfaces of the lens holder 22 and the focus coil/l/23, but the convex portion 22a prevents the adhesive from flowing out due to variations in the amount of adhesive applied. can. FIG. 3 is a plan view showing the structure of parts inside the lens holder of this embodiment. When the lens holder 22 moves in a direction perpendicular to the optical axis (Y direction in the figure), the convex portion 22a formed as described above moves against the inner yoke 27.
&'s inner yoke 27a and focus coil 2
3 and eliminates the occurrence of disconnection of the focus carp/L'23.

As described above, according to this embodiment, when fixing the focusing coil and the tracking coil to the lens holder, the coils can be positioned easily and reliably, and the adhesive can be prevented from flowing out from the lens holder. , it is possible to solve the problem of a reduction in the movable range of the lens holder due to adhesive extrusion. Furthermore, when the lens holder is driven in a direction perpendicular to the optical axis, the convex part is placed very close to the focus coil and acts as a stopper to prevent contact between the inner yoke and the focus coil, ensuring that the focus coil is It is possible to prevent the coil from breaking due to contact with the yoke.

The second embodiment of the present invention will be described with reference to FIG. 4 regarding the differences from the first embodiment. FIG. 4 is a diagram showing details of how the focusing coil and tracking coil of this embodiment are fixed to the lens holder. The difference from the first embodiment is that one side of the hollow part of the lens holder is removed, creating a U-shaped hollow part. The tracking coil 24 is bonded to the outer peripheral surface of the focus coil/l/23, and the focus coil 23 and the tracking coil 2
4 is inserted from the inner surface of the U-shaped hollow part of the lens holder 22 with a little margin than the thickness of the focus coil μ 23, and is positioned and bonded by relying on the convex portion 22a protruding around the lens holder 230.

In this embodiment as well, the same effects as in the first embodiment can be obtained.

As mentioned above, the first effect is as follows. According to the second embodiment, by providing a convex shape on the inner surface of the hollow portion through which the lens holder passes, it is possible to easily position the drive coil by relying on the convex portion when fixing it to the lens holder. This prevents the adhesive from flowing out from the adhesive surface between the lens holder and the drive coil, and by making this convex part contact the inner yoke and restricting the range of movement of the lens holder in the direction perpendicular to the optical axis, the drive coil and This objective lens driving device can achieve a number of excellent effects with a simple configuration, such as eliminating the possibility of contact with the inner yoke and preventing disconnection of the driving coil.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing the configuration of an objective lens drive device in an embodiment of the present invention, and FIGS. 2 and 4 show details of the fixed state of the drive coil and lens holder in each embodiment of the present invention. 3 is a plan view showing the configuration of parts inside a part of the lens holder of the present invention. FIG. 6 is an exploded perspective view showing the configuration of a conventional objective lens drive device. FIG. 7 is an exploded perspective view showing details of fixing the drive coil of the objective lens drive device and the lens holder, and FIG. 7 is a plan view showing the configuration of parts inside a part of the conventional lens holder. 11...Solder, 21...Objective lens,
22... Lens holder, 23... Focus coil, 24... Tracking coil, 26... Base, 26... Wire, 27... ... Yoke, 28 ... Magnet, 29 ... Base board, 30 ... Holder board, 31 ... Solder.

Claims (1)

[Scope of Claims] An objective lens for projecting a light spot onto an optical disk; a lens holder; driving means for driving the objective lens and the lens holder; a fixing member and a supporting member; the supporting member is fixed to the lens holder and the fixing member, respectively; and the driving means includes a focusing coil whose central axis is parallel to the optical axis of the objective lens, and a focusing coil whose central axis is parallel to the optical axis of the objective lens; It consists of a tracking coil whose axis is perpendicular to the optical axis and a magnetic circuit having a magnetic gap, and when the previously formed focus coil and tracking coil are inserted and fixed into the hollow part of the lens holder, An objective lens drive device, characterized in that the focusing coil is fixed to a convex portion protruding from an inner surface, and the convex portion restricts a movable range of the lens holder in a direction perpendicular to the optical axis.