JPS63204520A - Driver for objective lens - Google Patents

Abstract

PURPOSE:To fix wires on a holding means without using a hole by forming wire fitting grooves on the holding body, and under the state that the wires are arranged in the grooves, fixing the wires on the groove by a fixing means. CONSTITUTION:The wires 20 are fixed to the lower parts of both sides of the holding body 2 which are rectangular to both sides. Thereby, the holding body 2 is integratedly supported as a movable part by inserting four wires 20 into a block 25 mounted on a base 10. Namely, the objective lens driver 30 supports the objective lens 1 by fixing the wires 20 to the fitting grooves 6 so that the lens 1 can be driven in two direction, i.e. focus and track directions. Since the fitting grooves 6 are formed integratedly with the holding body 2, the fitting grooves can be easily and straight formed. Consequently, hole working causing the rise of price can be omitted.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is applied to, for example, an optical disk device that converges light onto an information recording medium to optically read information. The present invention relates to an objective lens driving device.

(Prior Art) In general, in this type of optical disk device, in order to accurately read information from an information recording medium, it is necessary to focus light on the information recording medium against "warpage" and "shake" of the recording medium. It is necessary to perform focus control to control the distance between the objective lens that emits light and the track position of the information recording medium on which information is written, and tracking control to control the objective lens to follow the center of the information track. be. Therefore, the objective lens must be held movably in the focus direction and the tracking direction.

Incidentally, the above-mentioned optical disk device is provided with an optical head as a device for optically reading information by converging light onto an information recording medium.

This optical head is provided with an objective lens driving device that holds the objective lens movably in the focusing direction and the tracking direction, and performs focus control and tracking control of the objective lens. In this objective lens driving device, as shown in FIG. 5, a holder 2 holding an objective lens 1 is movably supported by four wires 20 provided on a flat surface. In this case, the wire 20 is fitted into through holes 5, 5 formed in a part of the holder 2, and is bonded and fixed.

However, in the objective lens drive device 30, it is difficult to process the through hole 5 formed in the holder 2, which increases the cost.
Since the wire 20 is bent, distortion occurs in the wire 20, and the objective lens 1 tends to tilt, resulting in low accuracy in reading information and poor performance.

(Problems to be Solved by the Invention) This invention requires high costs because it is difficult to process the through holes to be drilled in the holder, and the holes are bent during the process of forming the through holes, so the wire This eliminates the disadvantages of distortion that causes the objective lens to tilt, resulting in low information reading accuracy and poor performance, making it possible to manufacture an objective lens drive device at a low cost, and preventing the objective lens from tilting. It is an object of the present invention to provide an objective lens driving device that can improve performance.

[Structure of the Invention] (Means for Solving the Problems) An objective lens driving device of the present invention includes an objective lens that focuses light onto an information recording medium, a holder that holds the objective lens, and a holder that holds the objective lens. In an objective lens driving device having a plurality of mutually parallel wires supporting a holder, the attachment formed on the holder and in which the wires are provided is a groove, and the attachment is in a state where the wire is arranged in the groove. and a fixing means for fixing the wire to the holder.

(Function) The present invention provides an objective lens that includes an objective lens that focuses light onto an information recording medium, a holder that holds this objective lens, and a plurality of mutually parallel wires that support this holder. In the drive device, the wire is attached to the holder by providing a groove in the holder, and with the wire placed in the groove, the wire and the holder are fixed by a fixing means, thereby attaching the wire to the holder without using a hole. and the wire are fixed.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 shows a schematic configuration of an optical disk device to which the present invention is applied. That is, the optical disc (information recording medium) 31 is driven by a spindle motor (not shown).
It is designed to be rotated at a constant linear velocity with respect to an optical head, which will be described later.

The optical disc 31 has a donut-shaped information recording layer made of tellurium or bismuth on the surface of a circular substrate made of glass or plastic, for example.

On the back side of the optical disc 31, an optical head 32 is provided as a gap for condensing light onto the optical disc 31 and optically reading information. This optical head 32 includes a semiconductor laser oscillator 33 as a light source, a half prism 34, a condensing lens 35, a reflecting mirror 3G, an objective lens 1, a cylindrical lens 37, information reproduction, track positional deviation, and focus direction blurring. It is composed of an optical system including a photodetector 38 for detecting.

By focusing the laser beam from the semiconductor laser oscillator 33 on the information recording layer of the optical disk 31 through an optical system such as the objective lens 1, the spiral grooves carved on the optical disk 31 can be Guide the imaging point to a predetermined position.

Therefore, information is read by irradiating laser light onto the optical disk 31 and detecting the reflected light by the photodetector 38 to recognize the presence or absence of bits. Note that when information is written by the optical head 32, the information recording layer on the optical disk 31 is melted by the heat of the laser beam to form bits.

In order to guide the laser beam to a predetermined position, an optical system detects defocus and track positional deviation, and a drive device (actuator) to be described later is driven via a servo circuit (not shown) to move the objective lens 1. Control is performed to eliminate blur in the focus direction and track position deviation.

FIG. 1 shows a schematic configuration of a driver 30 for driving the objective lens 1. As shown in FIG. That is, the objective lens 1
is fixed to a holder 2, and a focusing coil (driving coil in the focusing direction) 3 is wound around the holder 2, and two pairs of track coils (driving coils in the tracking direction) are wound on both sides of the holder 2. A coil) 4 is provided to form an integral movable part.

Furthermore, as shown in FIGS. 2(a) and 2(b), on the upper parts of both sides perpendicular to both side surfaces of the holding body 2, the mounting plate 6.6 is formed by injection molding of the plastic of the holding body 2. Sometimes it is integrally formed, and this installation is done by groove 6.
．． 6, two wires 20° 20 made of non-metallic fibers, for example, carbon fibers are distributed, and then the wires 20
and the holding body 2 are fixed.

In addition, at the lower part of both sides perpendicular to both side surfaces of the holding body 2,
The wires 20.20 are secured in the same manner as described above. Therefore, as shown in FIG. 1, the holder 2 is integrally supported as a movable part by having the other ends of the four wires 20 drilled into a block 25 attached to the base 10-1. It is configured to

That is, the objective lens drive drawing 30 is configured to support the objective lens 1 so that it can be driven in two directions: focus and track, by attaching and fixing the wire 20 to the groove 6. In this case, by integrally forming the mounting groove 6 on the holder 2, the mounting groove 6 can be easily formed, and the mounting groove 6 can be formed straight. This eliminates the need for hole machining, which is a cost issue, and can therefore be made cheaper than the conventional objective lens drive Im.

Furthermore, yokes lla, 11b, and 11c made of a magnetic material (e.g., Fe) are erected and integrally formed on the base 10, and a pair of magnets is provided on the inner wall surface of each of the yokes 11a and 11b. 12a and 12b are mounted facing each other, and the focus coil 3 and track coil 4 are wound around the outer periphery of the yoke 11G to form a magnetic circuit. Therefore, when a current 1 flows through the focus coil 3 and the track coil 4, as shown in FIG. 3(a).
In accordance with Fleming's left-hand rule, a force in the direction of arrow F is generated at the position shown by the dashed-dotted line due to the magnetic field shown by arrow B in FIG. Therefore, the movable part is moved by the force of the focus coil 3 acting in the focusing direction and the force of the easy coils 1 to 4 acting in the tracking direction.
A phenomenon occurs in which each of the book wires 20 is bent and moved in the direction indicated by the arrow F in the figure. At this time, the movement of the movable part is controlled by the wire 20 provided on the block 25.
It is suppressed by silicone rubber in a pipe (not shown) that is inserted, so that when this vibration system resonates, the vibration is extended by 111 m.

On the other hand, 13 is a printed circuit board (PC board) attached to the outer wall surface of the yoke 11a set up on the base 10, and the pattern of this printed circuit board 13 includes a focusing coil 3.
Lead wire 3L led out from both ends of the track coil 4
Lead wires 4L led out from both ends of the wire are soldered to each other, and further lead wires 14 are soldered to each other through the patterned copper foil for electrical connection. When current is supplied to the focus coil 3 or the track coil 4 through the lead wires 14, 3L, and 4L, the magnet 128.
Due to electromagnetic interaction with the lens 12b, the objective lens 1 and the holder 2 can be moved integrally in the focus direction or the track direction.

As described above, by forming a groove in the holder to attach the wire, and after placing the wire in this groove, fixing the wire and the holder using heat caulking or adhesive, the holder can be moved by the wire. It was designed to be supported.

That is, by forming a groove in the holder for attaching the wire, the wire and the holder can be fixed without using holes. In this +1 case, the groove for attaching the wire can be formed integrally when the holder is formed by injection molding of plastic, so it is easy to form the groove. As a result, costs can be reduced, and the driving position of the objective lens can be manufactured at low cost.

Furthermore, the mounting groove can be formed straight.

Therefore, since the wire can be attached without being distorted, the tilt of the objective lens can be prevented from cross-crossing, and the performance of the objective lens driving device can be improved, such as improving the accuracy of reading information.

[Effect of the Invention 1] As detailed above, according to the present invention, it is possible to manufacture an objective lens driving device at low cost, and
It is possible to provide an objective lens driving device that can prevent the objective lens from tilting and improve performance.

[Brief explanation of the drawing]

Figure 1 shows the drive 1 of an objective lens, which is an example of this invention.
FIG. 2 is a perspective view of a main part showing a schematic configuration of a movable part, FIG. 3 is a diagram showing an example of a magnetic field generated in a drive coil, and FIG. 4 is a diagram to which this invention is applied. FIG. 1 is a schematic configuration diagram of an optical disk device. FIG. 5 is a schematic PR configuration diagram of a conventional objective lens driving device. DESCRIPTION OF SYMBOLS 1... Objective lens, 2... Holder, 3... Focus coil, 4... Track coil, 6... Installation groove, 12a, 12b... Magnet, 2o... Wire, 30... Objective lens drive device, 31... Optical disk (information recording medium), 32... Optical head, 33
...Semiconductor laser oscillator. Applicant's representative Patent attorney Takehiko Suzue, 1 Figure 1 (a) Figure 2 (a) (b) 3 Figure 4 Figure 1a Figure 5

Claims (3)

[Claims] (1) An objective lens that focuses light onto an information recording medium;
An objective lens driving device having a holder for holding the objective lens and a plurality of mutually parallel wires supporting the holder, comprising: a mounting groove formed in the holder and in which the wires are provided; 1. An objective lens driving device comprising: fixing means for fixing the wire to a holder in a state in which the wire is disposed in the mounting groove. (2) The objective lens driving device according to claim 1, wherein the fixing means fixes the wire by thermally deforming the mounting groove. (3) The objective lens driving device according to claim 1 or 2, wherein the fixing means fixes the wire with an adhesive.