JPS60140548A - Optical pickup actuator - Google Patents

Abstract

PURPOSE:To make a device small in size by constituting a coil for tracking with a flexible printed circuit and using it as a bobbin of a coil for focusing to reduce the total thickness of the coil and the bobbin which are inserted to a magnetic gap. CONSTITUTION:A bobbin 7 consists of a flexible printed board where coil patterns 70 for tracking are formed on both faces, and a focusing coil 11 is wound around the bobbin 7. A lens 8 is moved in the direction of an arrow A together with a lens driving plate 4 when a current is flowed to the focusing coil 11, and the lens driving plate 4 is rotated around a shaft 5 to move the lens 8 in the direction of an arrow B when a current is flowed to coil patterns 70 for tracking. Since the total thickness of the coil 11 and the bobbin 7 inserted to the magnetic gap is reduced, the magnetic gap can be made narrower, and the device is made small in size, and the magnetic flux density in the gap part is raised, and the power efficiency of an actuator is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to an optical pickup cutter.

[Prior art and its problems]

The conventional moving coil type actuator.

As shown in FIG. 1, a tracking plane coil 2 is attached to a coil bobbin 1 and a focusing coil 3 is wound around the outer side of the coil bobbin 1, or a focusing coil 3 is wound around a coil bobbin 1 and a tracking plane coil 2 is attached to the outer side of the coil bobbin 1. It was pasted.

The tracking coils are usually 41 to 8 in number, and are connected in 11 rows. Aerial wiring of Tongi Enamelled Wire is not carried out because it lacks reliability. Therefore, it is necessary to connect the coils using a printed circuit board, and a space must be created in the actuator movable section to place the printed circuit board. This space has been an obstacle to miniaturizing the actuator.

[Purpose of the invention]

This invention improves the drawbacks of the conventional device mentioned above.
The purpose is to provide a small and highly reliable optical pickup actuator.

[Low wall of invention]

A tracking coil pattern is formed.

A flexible printed circuit board is used as a bobbin, and a focusing coil is wound around the bobbin and then adhesively hardened to move the lens in the focusing direction and the tracking direction.

〔Effect of the invention〕

All of the tracking coil patterns formed on the flexible printed circuit board are formed in a continuous manner on the flexible printed circuit board, so there is no need to connect the coils to each other.

Usually the lead wire connects the moving part coil and the stationary part.

To prevent the influence of the rigidity of the lead wire from appearing on the imaging characteristics,
Although stranded wires with low rigidity are used, solder joints for the stranded wires can be simultaneously formed on the flexible printed circuit board on which the tracking coil pattern is formed.

Since the flexible printed circuit board for the tracking coil also serves as a bobbin, the total thickness of the coil inserted between the magnetic gap and the bobbin can be reduced. magnetic flux density increases.

The power efficiency of the actuator can be improved.

[Embodiments of the invention]

FIG. 2 is a cross-sectional perspective view showing an example of the invention.

Fig. 3 1al is a plan view thereof, Fig. 3 1al is a side sectional view thereof, Fig. 4 is a partially sectional perspective view of the movable part, and Fig. 5 1a.
1 is a diagram showing a pattern on the front surface of the flexible printed circuit board, and FIG. 5 1al is a pattern on the back surface thereof.

The lens drive plate 4 has a bearing 6 in the center that can freely rotate and slide around a support 5, and a coil bobbin 7 is joined to the bearing 6 so as to form a concentric circle. The lens and drive plate 41 are attached at positions where the lens 8 and counterweight 9 face each other with the bearing 6 in between. The neutral position of the lens shaft moving plate 4 is determined by a damper 10. The bobbin is composed of a flexible printed circuit board with a tracking coil pattern 70 formed on both sides as shown in FIG.
1 is wrapped. The current that enters from the connection part 71 of the tracking coil pattern 70 flows from the front and back connection parts 72 to the pattern on the back side, returns to the front side through the front width connection part 73, and is inserted into the front and back connection parts 74 and 75. Through connection part 7
It reaches 6. The focusing coil 11 is connected to a terminal connection part 77. and connection parts 71, 76.
A lead wire for supplying current to 78 is connected. A magnetic field is applied to the necessary parts by the magnet 12° yoke 13 and center ball 14, and by passing current through the focusing coil 11, the lens 8 moves in the direction of the arrow along with the lens drive plate 4, and the tracking coil pattern 50 By passing a current through.

The lens drive plate 4 rotates around 1'@5, and the lens 8 moves in the direction of arrow B.

As described above, since the bobbin 7 is made up of the flexible printed circuit board I on which the tracking coil pattern 70 is formed, the combined thickness of the bobbin and the coil inserted into the curve of the magnetic gap becomes thin, so the magnetic By narrowing the gap, the magnetic flux density at the gap increases, which improves the power efficiency of the actuator.

Furthermore, since the tracking coil pattern 7o is formed continuously, there is no need for connection using wire rods, and accidents due to poor soldering are reduced.

Furthermore, by providing connection parts 77 and 78 on the flexible printed circuit board (constituting the bobbin 7) as terminals for connecting the lead wire that supplies current to the focus coil and the focus coil, it is possible to use the terminal at another location. This eliminates the need to prepare a space for placing the board, making it possible to downsize.

[Other embodiments of the invention]

In the actual winding example described above, an actuator was described in which a coil bobbin was constructed using a flexible printed circuit board with a pattern as shown in FIG.
The bobbin may be constructed of a flexible printed circuit board as shown in the figure. FIG. 6 shows an example in which a tracking coil pattern is formed only on the back surface, and FIG. 7 shows an example in which the bobbin is constructed from a two-layer flexible printed circuit board.

[Brief explanation of the drawing]

Fig. 1 is a perspective view illustrating a conventional optical pickup actuator, Fig. 2 is a partially sectional perspective view (b) showing an example of the present invention, and Fig. 3 ('al is a plan view thereof. 1b+ is a side sectional view thereof, FIG. 4 is a partially sectional perspective view of the lens driving plate and the bobbin, FIG. 5 (al is a front view showing the surface pattern of the flexible printed circuit board constituting the bobbin, and FIG. 6+al is a front view showing the surface pattern of a flexible printed circuit board constituting a bobbin in another embodiment; FIG. 3 1b+ is a front view showing the back pattern;
FIG. 7(al di) is a front view showing the surface pattern of the flexible printed circuit board constituting the bobbin in another embodiment, and FIG. 7 1bl is a front view showing the back surface pattern. 1.7.・Bobbin, 2...Tracking coil, 3
゜11... Focusing coil, 4... Lens drive plate. 5... shaft, 6... bearing, 8... lens, 9...
Counterweight, 10... Damper, 12... Magnet, 13... Yoke, 14... Center pole. 70...Coil pattern, 71,76.78...Connection part, ? 2, 73, 74.75...Front and back connection part, 77
...Terminal connection. Representative Patent Attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 2 Figure 3 (cL) (b) Figure 4 Figure 5 7Z 73 74 7S Figure 6 (α) (b)

Claims (1)

[Claims] An optical pickup actuator that drives an objective lens or an optical component movable at the same time as the objective lens for focusing and tracking control is equipped with a tracking coil made of a flexible printed circuit, which is formed into a tooth shape for focusing. An optical pickup actuator characterized by being a bobbin for a coil for use.