JP2002163832A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce distortion caused by the variation of temperature of a wiring substrate of a lens-moving body in optical means. SOLUTION: The present device which irradiates light L through the optical means and receives the reflected part of the light L. In addition, the device has a biaxial actuator 12 with the optical means, and the biaxial actuator 12 is provided with at least a wiring substrate 15, a coil body 18 which controls the posture of an objective lens 14 and linear messenger wires 21A to 21D which connect the coil body 18 with the wiring substrate 15. The wiring substrate 15 has on one of its surfaces a print wire or land pattern of prescribed form, material and/or thickness, for connecting the messenger wires 21A to 21D and on its other surface a print wire or land pattern of almost the same form, material and/or thickness as those of the above print wire or land pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device suitable for application to a recording / reproducing device equipped with a biaxial actuator for driving an objective lens. Specifically, a first metal pattern having a predetermined shape, material and / or thickness for joining a support member is provided on one surface of the substrate of the biaxial actuator, and a first metal pattern is provided on the other surface. A supporting member connected to the lens movable body so as to provide a second metal pattern having substantially the same shape, material, and / or thickness as the pattern, so as to offset the warpage of the wiring board due to a change in the operating temperature of the device on the front and back sides; In order to reduce distortion.

[0002]

2. Description of the Related Art In recent years, information recording media such as CDs (Compa
Optical discs such as ct discs and MDs (mini discs) and magneto-optical discs, and recording / reproducing apparatuses are widely used for recording information on these optical discs and reproducing information from the optical discs. These recording / reproducing apparatuses are equipped with an optical pickup device, and irradiate pits and grooves formed on the information recording surface of these optical discs with a light spot to record and reproduce information.

FIG. 5 shows an optical pickup device 1 according to a conventional example.
It is a front view of the partial crushing which shows the example of a 0 structure. The optical pickup device 10 shown in FIG. 5 includes a light emitting / receiving element 3 for irradiating and receiving light L, a wiring board 5 and a lens movable body 6 constituting the biaxial actuator 2. Wiring board 5
And the lens movable body 6 are four messenger wires 21
They are electrically and mechanically connected by A to 21D (the messenger wires 21B and 21C are not shown).
The objective lens 4 is attached to the lens movable body 6. The light emitting / receiving element 3 is attached to the main body substrate 1 below the objective lens 4.
Irradiates light L onto an information recording medium 40 such as an optical disk or a magneto-optical disk through the
(Hereinafter referred to as return light) L.

A wiring board 5 constituting the biaxial actuator 2 is formed with a land pattern for solder bonding, a printed wiring, and the like (not shown). A coil body 8 such as a focus coil or a tracking coil is attached to the lens movable body 6. A predetermined current is supplied to the coil body 8, and a framing between the magnetic body 9 and the magnetic member 9 provided on the main body substrate 1 is performed. The attitude of the objective lens 4 is controlled according to the left-hand rule.

[0005]

According to the conventional optical pickup device 10, a printed wiring or a land pattern 5A is provided on one surface of a wiring board 5 shown in FIG. 6, and four messenger wires 21A are provided. .. 21D. On the other surface of the wiring board 5, a main board fixing margin 1A formed by bending the main board 1 is formed.
Are adhered and fixed. Therefore, the following problem occurs.

When the operating temperature of the device 10 changes, the wiring board 5 shown in FIG. 6 is deformed and the lens posture changes. This deformation is caused by the glass epoxy resin forming the wiring board 5, the printed wiring and the land pattern 5A.
It is thought that this occurs due to the difference in linear expansion coefficient between the copper foils constituting the above. The wiring board 5 warps in a direction away from the main board fixing margin 1A like a bimetal. Therefore, a tensile force is generated on the wiring substrate side, and although the displacement is about several μm, the posture of the objective lens 4 whose position is regulated via the messenger wire changes, and the performance of the optical pickup device may be deteriorated. .

Further, when the method of joining the main board fixing portion 1 A and the wiring board 5 by soldering is adopted, the wiring board 5 shown in FIG. 6 is deformed and a large stress is applied to the solder joint portion 7. In addition, there is a possibility that the fixing failure of the wiring board 5 may be caused due to the solder peeling.

Further, in an information recording medium 40 such as an optical disk or a magneto-optical disk, pits and grooves are reduced as compared with the diameter of a light spot, and information is recorded at a high density. Therefore, there is a possibility that information on adjacent pits or grooves may be picked up as noise due to the displacement of the objective lens 4 (hereinafter also referred to as optical system means) of about several μm.

In view of the above, the present invention has been made to solve such a conventional problem, and is intended to reduce the distortion caused by a change in the temperature of a wiring board applied to a lens movable body to which an optical system is attached. It is an object to provide a pickup device.

[0010]

In order to solve the above-mentioned problems, an optical pickup device according to the present invention is a device for irradiating light through an optical system means and receiving a return of the light. Comprising a two-axis actuator fitted with means, wherein the two-axis actuator comprises at least
A substrate, a coil body for controlling the attitude of the optical system means, and a linear support member for connecting the coil body and the substrate are provided, and the substrate has a predetermined surface for joining the support member to one surface. It is necessary to have a first metal pattern of shape, material and / or thickness, and to have a second metal pattern of the same shape, material and / or thickness as the first metal pattern on the other surface. It is a feature.

[0011] According to the optical pickup device of the present invention, the bimetal structure of the substrate of the biaxial actuator and the metal pattern provided on one surface, and the bimetal structure of the substrate and the metal pattern provided on the other surface are provided. Can be made substantially equal. Therefore, it is possible to cancel the warpage of the substrate due to the change in the operating temperature of the device, and to eliminate the distortion applied to the support member connected to the coil body. This makes it possible to control the attitude of the optical system means with high accuracy while eliminating the influence of the change in operating temperature.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical pickup device according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing a configuration example of an optical pickup device as an embodiment of the present invention. In this embodiment, a first shape, material, and / or thickness for joining a support member to one surface of a substrate of a biaxial actuator is used.
And a second metal pattern having substantially the same shape, material, and / or thickness as the first metal pattern is provided on the other surface, and a metal pattern provided on the substrate and one surface is provided. The bimetal structure and the bimetal structure of the substrate and the metal pattern provided on the other surface are made substantially equal so that the warpage of the wiring board due to a change in the operating temperature of the device is offset on the front and back.

The optical pickup device 100 shown in FIG.
It has an objective lens 14 as an example of the optical system means,
This is a device that irradiates light L onto an information recording medium (not shown) through the objective lens 14 and receives light L (hereinafter referred to as return light) returning from the information recording medium.
The information recording medium is an optical disk, a magneto-optical disk, or the like.

The optical pickup device 100 includes a main substrate 1
It has a one- and two-axis actuator 12 and a light emitting / receiving element 13. The objective lens 14 is a biaxial actuator 12
Attached to. The main body substrate 11 is made of an iron member including a pressed portion. A biaxial actuator 12 is attached to one side of the main body substrate 11, and controls the objective lens 14 so as to be movable in X, Y, and Z directions. An opening 11A is provided in the main body substrate 11, and a light emitting / receiving element 13 is attached to the other side of the main body substrate 11 so as to be aligned with the opening 11A. While irradiating the medium, the medium receives the return light L from the information recording medium.

The biaxial actuator 12 has at least a wiring board 15 and a lens movable body 16. The wiring board 15 is fixed so as to hold a part of the main board 11. Body board fixing margin 11 for fixing wiring board 15
B is formed by making a cut in a predetermined shape in the main body substrate 11 and bending the cut. The main board fixing margin 11B and the wiring board 15 are joined by soldering. On the wiring board 15, a land pattern 5A for solder bonding, which is an example of a first metal pattern, a printed wiring, and the like are formed.

The lens movable body 16 has a frame 17 and a coil 18 of a predetermined shape in addition to the objective lens 14. The frame 17 is, for example, about 15 mm long, about 8 mm wide,
It has an elongated pentagonal column shape with a height of about 3 mm, and three opening portions 17A to 17C are provided inside thereof. The frame 17 is prepared by injection molding a resin. Opening portion (first opening portion) 17A at one end of frame 17
Is mounted with an objective lens 14, and the light emitting / receiving element 1
3 to form an image of the light emitted to the information recording medium, and form an image of the return light from the information recording medium.

The center opening (second opening) 17B has a U
One end of a U-shaped magnetic member 19 is provided to form a magnetic path. The magnetic member 19 includes a permanent magnet 20 and a U-shaped iron member. The U-shaped iron member is formed, for example, by cutting the main substrate 11 into a predetermined shape and bending them. The other end of the opening (third opening) 17C at the other end is provided with the other end of the coil body 18 and the magnetic member 19 so that the attitude of the objective lens 14 is controlled.

One end of the magnetic member 19 (for example, S pole)
Extends from the main body substrate 11 to the inside of the second opening 17B. The other end (N pole) extends from the main body substrate 11 to the inside of the coil body 18 of the third opening 17C. The permanent magnet 20 is bonded to the inner surface of the U-shaped magnetic member 19 at the third opening 17C. A focus coil 81 constituting one side of the coil body 18 is attached to the third opening 17C so as to adjust the focus of the objective lens 14. A tracking coil 82 is attached to one side surface of the focus coil 81 so as to adjust tracking of the light L emitted through the objective lens 14.

Relay terminals 71 are provided on both side surfaces of the frame 17, and the electric wires 32 are connected to the winding start portions of the focus coil 81 and the tracking coil 82 and the terminal portions thereof. Between the relay terminals 71 on both sides of the frame body 17 and the wiring board 15, a linear 4 as an example of a support member is provided.
The messenger wires 21A to 21D are attached. The messenger wires 21 </ b> A, 21 </ b> D and the like and the relay terminal 71 are electrically and mechanically connected by a solder joint 33. Each messenger wire 2
For 1A to 21D, beryllium copper having a thickness of about 90 μm to 100 μm is used so as to exhibit elasticity and conductivity.

As a result, the lens movable body itself can be freely moved in the magnetic field, and current is guided to the focus coil 81 and the tracking coil 82. That is, Fleming's left-hand rule is applied between a power point which is an intersection of a first operation axis formed by the focus coil 81 and a second operation axis formed by the tracking coil 82, and a magnetic field formed by the magnetic member 19 and the permanent magnet 20. Thereby, the lens movable body 16 is made movable.

FIG. 2 is a front view showing a layout example of the printed wirings 23A to 23D on the wiring board 15. The wiring board 15 shown in FIG. 2 has, for example, a horizontal H shape having a width of about 15 mm, a width of about 8 mm, and a thickness of about 1.5 mm, and is made of, for example, glass epoxy resin. . In this wiring board 15, four land patterns 22 joining the four messenger wires 21A to 21D connected to the relay terminal 71 shown in FIG.
A to 22D are arranged at the four corners of the wiring board 15 shown in FIG. 2, and printed wirings 23A to 23D are arranged so as to extend to the land patterns 22A to 22D and the like, and to the terminal portions of the printed wirings 23A to 23D. Are provided with terminals 24A to 24D for external wiring. An opening 25 for bonding is provided at the lower center of the wiring board 15, and the main board fixing portion 11B and the wiring board 15 are fixed by soldering.

FIG. 3 is a sectional view taken along the line X1-X2 showing an example of the structure of the front and back surfaces of the wiring board 15. A predetermined shape, material, and / or thickness as an example of a first metal pattern for joining the four messenger wires 21A to 21D shown in FIG. 1 to one surface of the wiring board 15 shown in FIG. Land patterns 22A to 22D and printed wiring 23
A to 23D, and a second metal pattern having substantially the same shape, material, and / or thickness as the land patterns 22A to 22D and the printed wirings 23A to 23D is provided on the other surface (main body substrate fixing margin side). Printed wirings 26A to 26D for preventing warpage and land pattern 28A as an example
~ 28D.

Each of the land patterns 22A to 22D, 2
8A to 28D and printed wiring 23A to 23D, 26A
26D is composed of a copper foil pattern having a predetermined thickness. The layout of the printed wirings 26A to 26D for preventing warpage and the land patterns 28A to 28D is the same as that of the land patterns 22A to 22D for relay and the printed wiring 2A.
It is almost the same as the layout of 3A to 23D (see FIG. 2). The printed wirings 26A to 26D and the land patterns 28A to 28D are used by being electrically short-circuited by the main board fixing margin 11B.

In FIG. 3, four wires for passing the messenger wires 21A to 21D shown in FIG.
Openings 27A to 27D (openings 27B and 27C are not shown) are provided. These openings 27A, 27D
For example, a circular copper foil having an outer diameter of about w1 and w2, which constitutes the land patterns 22A to 22D of the relay printed wirings 23A to 23D, is arranged on one surface in accordance with the opening position such as. On the other surface of the wiring board 15, land patterns 28 of printed wirings 26A to 26D for preventing warpage are provided.
For example, a circular copper foil pattern having an outer diameter of about w1 and w2 constituting A to 28D is arranged. The land patterns 28A to 28D are provided with openings 29A to 29C.

Here, the diameter of the opening 27A of the land pattern 22A for relay is d1, the diameter of the opening 29A of the land pattern 28A for warpage prevention is d2, and the opening of the land pattern 22D for relay is 22d. The diameter of 27D is d3, and the opening 29D of the land pattern 28D for preventing warpage.
The aperture d2 of the aperture 29A is set to be larger than the aperture d1 of the aperture 27A (d2> d1), and similarly, the aperture 2 is determined by the aperture d3 of the aperture 27D.
The diameter d4 of 9D is set large (d4> d3). This is because the messenger wires 21A to 21D have an elastic function and also have a function of flowing an electric current to the focus coil 81 and the tracking coil 82, so that an insulation distance is secured to the main board fixing margin 11B. That's why. Normally, the main board fixing margin 11B is kept at the ground potential.

Next, an operation example of the optical pickup device 100 will be described. FIG. 4 shows the wiring board 15 and the main board fixing allowance 1.
FIG. 1B is a cross-sectional view illustrating an example of a connection configuration between 1B and the lens movable body 16. In FIG. 4, a damper member 30 made of resin is attached to the right side of the main board fixing margin 11B to regulate the moving range of the lens movable body 16 in the X, Y, and Z directions. The damper member 30 has four opening portions 31.
A to 31D are provided, and the above-described messenger wires 21A to 21D are passed through and used. This is because the messenger wires 21A-
This is for restricting the movement of 21D. Opening 31B, 3
1C is not shown.

On the premise of this, in the optical pickup device 100 shown in FIG. 4, relay land patterns 22A to 22D and printed wirings 23A to 23D provided on one surface of the wiring board 15, and the wiring board 15 The bimetal structure of the wiring board 15 is substantially equal to the land patterns 28A to 28D and the printed wirings 23A to 26D for preventing warpage provided on the other surface of the wiring board 15. That is, when the strain stress due to the bimetal structure of the relay printed wirings 23A to 23D and the like and the wiring board 15 is Fa, and the strain stress due to the bimetal structure due to the printed wiring 26A to 26D and the wiring board 15 for preventing warping is Fb. , Fa = F
The relationship of b is maintained.

In the optical pickup device 100, a predetermined current is supplied to the focus coil 81 to adjust the focus of the objective lens 14, and a predetermined current is also supplied to the tracking coil 82 in the same manner as in the conventional example. 1
4 to adjust the tracking of the light L illuminated therethrough.

When the objective lens 14 is optimally adjusted, the information recording medium is irradiated with light L through the objective lens 14 and receives the return light L from the information recording medium (see FIG. 1). 1). At this time, even when the operating temperature of the device 100 changes, the above-described relationship of Fa = Fb is maintained, so that the warpage of the wiring board 15 can be canceled.

Therefore, since the distortion given to the messenger wires 21A to 21D connected to the lens movable body 16 can be eliminated, the posture of the objective lens 14 can be adjusted with high accuracy while the change in the optical axis due to the change in operating temperature is removed. Can be controlled. As a result, information can be read with high reproducibility and high accuracy from an optical disk or a magneto-optical disk that is increasingly miniaturized and densified. It is possible to provide a highly reliable recording / reproducing device equipped with the optical pickup device 100.

Moreover, since the deformation of the wiring board 15 due to heat can be completely eliminated, the main board fixing allowance 1 can be formed by a solder bonding method.
1B and the wiring board 15 can be joined. Thereby, the assembly of the optical pickup device 100 can be simplified and the cost can be reduced.

[0033]

As described above, according to the optical pickup device of the present invention, one surface of the substrate of the biaxial actuator has a predetermined shape, material and / or thickness for joining the support member. One metal pattern is provided, and a second metal pattern having substantially the same shape, material, and / or thickness as the first metal pattern is provided on the other surface.

With this configuration, the bimetal structure formed by the substrate and the metal pattern provided on one surface can be made substantially equal to the bimetal structure formed by the substrate and the metal pattern provided on the other surface. The warpage of the substrate due to the change in the operating temperature can be canceled. Thus, since the distortion given to the support member connected to the coil body can be eliminated, the posture of the optical system means can be controlled with high accuracy while eliminating the influence of the change in the operating temperature. The present invention is extremely suitable for application to a recording / reproducing apparatus equipped with a biaxial actuator for driving an objective lens.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration example of an optical pickup device 100 as an embodiment of the present invention.

FIG. 2 is a front view showing a layout example of relay land patterns 22A to 22D and printed wirings 23A to 23D on a wiring board 15;

FIG. 3 is a diagram illustrating a configuration example of X1 on the front and back of the wiring board 15;
It is X2 arrow sectional drawing.

FIG. 4 is an enlarged front view of a partially crushed structure showing a connection configuration example of a wiring board 15, a main board fixing margin 11B, a lens movable body 16, and the like.

FIG. 5 is a partially fragmented front view showing a configuration example of an optical pickup device 10 according to a conventional example.

FIG. 6 is a partially fragmented enlarged front view showing a connection configuration example of the lens movable body 6 and the like.

[Explanation of symbols]

 Reference Signs List 12 biaxial actuator 13 light emitting / receiving element 14 objective lens (optical system means) 15 wiring board 16 lens movable body 18 coil body 19 magnetic member 21 messenger wire (supporting member) 71 relay terminal 81 focus coil (coil body) 82 tracking coil (Coil) 100 Optical pickup device

Claims (2)

[Claims] 1. A device for irradiating light through an optical system means and receiving a return of the light, comprising: a two-axis actuator having the optical system means attached thereto; A substrate, a coil body for controlling the attitude of the optical system means, and a linear support member for connecting the coil body and the substrate, wherein the substrate joins the support member to one surface. Predetermined shape, for
It has a first metal pattern of material and / or thickness, and has a second metal pattern of the same shape, material and / or thickness as the first metal pattern on the other surface. Optical pickup device. 2. The substrate has a plurality of openings through which the support member passes, and holes are formed in the first metal pattern and the second metal pattern in accordance with the opening positions of the openings. When the aperture of the aperture of the first metal pattern is d1 and the aperture of the aperture of the second metal pattern is d2, the aperture is determined from the aperture d1 of the aperture. 2. The optical pickup device according to claim 1, wherein the diameter d2 of the section is set large.