JP2012069213A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup device that is realized as a downsized device.SOLUTION: An optical pickup device includes: a first object lens which collects light from a first light source; a second object lens which collects light from a second light source; a lens holder which holds the first object lens and the second object lens; a focusing coil which is fixed to the lens holder, and which drives the lens holder in a focusing direction; a focusing magnet which provides a uniform magnetic field over the focusing coil; a main yoke 13 which includes iron as a base material and is covered with plating mainly containing nickel and phosphorus, and which elastically supports the lens holder; sub-yokes 14 and 15 which include iron as a base material and are covered with plating mainly containing nickel and phosphorus, and which support the focusing magnet; and a base 4 which is formed by welding the main yoke 13 and the two sub-yokes 14 and 15. A welded portion 16 of the base 4 includes about 90% of iron, about 9% of nickel, and about 1% of phosphorus.

Description

  The present invention relates to an optical pickup device capable of recording on or reproducing a plurality of types of optical disks.

  An optical pickup device capable of recording on or reproducing a plurality of types of optical discs may require a plurality of objective lenses. For example, recording on BD (Blu-Ray Disk, hereinafter simply referred to as BD), DVD (Digital Versatile Disk, hereinafter simply referred to as DVD), CD (Compact Disk, hereinafter simply referred to as CD), or recording BD, DVD, CD. In the case of an optical pickup device that can be reproduced, two objective lenses are usually required, that is, an objective lens for BD and an objective lens for DVD / CD.

  Further, the optical pickup device has a base that supports the components constituting the optical pickup device. The base is formed from a plurality of yokes.

JP-A-8-335374

  In the above conventional configuration, since the optical pickup device has a plurality of objective lenses, in order to reduce the size of the optical pickup device, each component constituting the optical pickup device is reduced in size and the base material thickness of the yoke is reduced. It must be thinned.

  However, when the thinned yoke is welded to form a base on which the components constituting the optical pickup device are mounted, there is a problem that the yoke is deformed and the device cannot be reduced in size.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an optical pickup device capable of downsizing the device.

  The present invention has been made to solve the above-described problem, and includes a first objective lens that condenses the light from the first light source, a second objective lens that condenses the light from the second light source, A lens holder for holding one objective lens and a second objective lens; a focus coil fixed to the lens holder for driving the lens holder in the focus direction; a focus magnet for applying a uniform magnetic field to the focus coil; A first yoke that is covered with a plating containing phosphorus as a main component and elastically supports the lens holder, and a second yoke that is covered with a plating containing iron and nickel and phosphorus as the main components and supports the focus magnet. A base formed by welding the first yoke and the two second yokes, and the welded portion of the base is composed of about 90% iron, about 9% nickel, and about 1% phosphorus. This An optical pickup apparatus according to claim.

  According to the present invention, the strength of the joint portion between the yokes can be secured without deforming the first yoke and the second yoke. As a result, an optical pickup device that can reduce the size of the device can be realized.

1 is an external view showing an optical pickup device in Embodiment 1 of the present invention. FIG. 2 is a detail view of a main part of the optical pickup device according to the first embodiment of the present invention. The figure which shows a mode that the main yoke and sub yoke in Embodiment 1 of this invention are joined. The figure which shows the phosphorus density | concentration in plating and welding strength in Embodiment 1 of this invention The figure which shows the plating thickness and welding strength in Embodiment 1 of this invention The figure which shows the constituent material ratio of each position of the welding part in Embodiment 1 of this invention.

  The invention according to claim 1 is a first objective lens that condenses light from the first light source, a second objective lens that condenses light from the second light source, a first objective lens, and a second objective lens. A lens holder that holds the lens, a focus coil that is fixed to the lens holder and drives the lens holder in the focus direction, a focus magnet that applies a uniform magnetic field to the focus coil, and a plating mainly composed of iron and nickel and phosphorus. A first yoke that elastically supports the lens holder that is covered, a second yoke that is covered with an iron-based plating mainly composed of nickel and phosphorus, and that supports the focus magnet, a first yoke, and two second yokes A base formed by welding the yoke, and the welded portion of the base is composed of about 90% iron, about 9% nickel, and about 1% phosphorus. Thereby, the strength of the joint portion between the yokes can be ensured without deforming the first yoke and the second yoke. As a result, an optical pickup device that can reduce the size of the device can be realized.

  The invention described in claim 2 is characterized in that the first yoke and the second yoke are made of iron and plated with nickel of about 97% and phosphorus concentration of about 3% or less. . Accordingly, when welding the first yoke and the second yoke, no metal other than the first yoke and the second yoke is required as a welding material, and the structure of the joint portion between the first yoke and the second yoke is provided. The composition ratio of the material can easily be about 90% iron, about 9% nickel, and about 1% phosphorus.

  The invention described in claim 3 is characterized in that the plating thickness of the first yoke and the second yoke is about 3 μm. As a result, when the first yoke and the second yoke are welded, the constituent ratio of the constituent material of the joint portion between the first yoke and the second yoke is efficiently set to about 90% iron, about 9% nickel, about 1 phosphorus. %.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings.

  FIG. 1 is an external view showing an optical pickup device according to Embodiment 1 of the present invention. In FIG. 1, 1 is a first objective lens, 2 is a second objective lens, 3 is a lens holder, 4 is a base, 5 is a suspension, 6 is a suspension holder, 7 and 8 are focus coils, and 9 and 10 are focus magnets. , 11 and 12 are focus magnets.

  The optical pickup device has two light sources that emit laser light having a first wavelength and laser light having a second wavelength. A first light source that emits a laser beam having a first wavelength emits a laser beam having a wavelength of 400 nm to 415 nm and is used to record or reproduce a BD. On the other hand, the second light source that emits laser light having the second wavelength emits laser light having a wavelength of 640 nm to 800 nm. When the wavelength of the emitted laser light is 660 nm, it is used for recording on a DVD or reproducing the DVD. Further, when the wavelength of the emitted laser light is 780 nm, it is used for recording on a CD or reproducing the CD.

  The first objective lens 1 condenses the laser light having the first wavelength emitted from the first light source on the recording surface of the optical disc. The second objective lens 2 condenses the laser light having the second wavelength emitted from the second light source on the recording surface of the optical disc. The first objective lens and the second objective lens are made of a material such as glass or resin.

  The lens holder 3 holds the first objective lens 1 and the second objective lens 2 so that the lens surface faces the optical disk. The suspension 5 is provided so as to sandwich the lens holder 3 and elastically connects the lens holder 3 and the suspension holder 6. The suspension holder 6 is attached to the upper surface of the base 4 and supports the lens holder 3 so as to be movable within a predetermined range with respect to the base 4. The base 4 holds components such as a magnet necessary for moving the lens holder 3 within a predetermined range.

  The focus coils 7 and 8 are wound in a substantially ring shape, and the focus coil 7 and the focus coil 8 are positioned so as to sandwich the lens holder 3, and each is fixed to the side surface of the lens holder 3. The focus magnets 9 and 10 are magnets having a function of applying a uniform magnetic field to the focus coil 7, and the focus coil 7 is located between the focus magnet 9 and the focus magnet 10. The focus magnets 11 and 12 are magnets having a function of applying a uniform magnetic field to the focus coil 8, and the focus coil 8 is located between the focus magnet 11 and the focus magnet 12.

  FIG. 2 is a detailed view of a main part of the optical pickup device according to the first embodiment of the present invention, and shows the relationship between the main yoke, the sub yoke, and the focus magnet. In FIG. 2, 13 is a main yoke, 14 and 15 are sub-yokes, 14a, 14b, 14c, 15a, 15b and 15c are standing portions, and 16 is a welded portion. In the first embodiment, the first yoke is the main yoke 13, and the second yoke is the sub-yokes 14 and 15.

  The base 4 includes a main yoke 13 and sub yokes 14 and 15. The main yoke 13 has a substantially rectangular shape, and the sub-yoke 14 is disposed on one side surface 13 a that forms the main yoke 13. The sub yoke 15 is disposed on a side surface 13b different from the side surface 13a on which the sub yoke 14 is disposed. The main yoke 13 supports the lens holder 3 via the suspension 5 and the suspension holder 6 shown in FIG. The sub-yoke 14 has three standing portions 14a, 14b, 14c that rise vertically from the bottom surface, and the focus magnets 9, 10 are fixed to the standing portions 14a, 14c located at both ends, respectively. Similarly, the sub-yoke 15 has three standing portions 15a, 15b, and 15c that rise vertically from the bottom surface, and the focus magnets 11 and 12 are fixed to the standing portions 15a and 15c located at both ends, respectively.

  The main yoke 13 and the sub yokes 14 and 15 are joined by welding. The upper surface of the main yoke 13 and the lower surfaces of the sub yokes 14 and 15 are overlapped, and heat is applied to form the welded portion 16.

  In the first embodiment, the welded portion 16 is formed by irradiating laser light onto the boundary between a predetermined surface of the main yoke 13 and the surfaces of the sub yokes 14 and 15 adjacent to the predetermined surface. Three welds 16 are formed between the main yoke 13 and the sub yoke 14, and three welds 16 are also formed between the main yoke 13 and the sub yoke 15.

  3A and 3B are diagrams showing a state in which the main yoke and the sub yoke are joined in Embodiment 1 of the present invention. FIG. 3A shows a state in which the main yoke and the sub yoke are brought close to each other, and FIG. FIG. 3C shows a state in which the yoke and the sub yoke are brought into contact with each other, and FIG. 3C shows a state in which the main yoke and the sub yoke are joined. In FIG. 3, 13c is a surface and 14d is a surface. In FIG. 3, the vertical direction of the paper corresponds to the thickness direction of the main yoke and the sub yoke.

  The main yoke 13 is covered with a plating mainly composed of nickel and phosphorus using iron as a base material. Similarly to the main yoke 13, the sub yokes 14 and 15 are covered with a plating containing iron and nickel and phosphorus as main components. The thickness of the plating mainly composed of nickel and phosphorus is about 3 μm to 5 μm for both the main yoke 13 and the sub yokes 14, 15, and the thickness of the main yoke 13 and the sub yokes 14, 15 is about 0.4 mm to 0.6 mm. It is. Although FIG. 3 shows the relationship between the main yoke 13 and the sub yoke 14, the relationship between the main yoke 13 and the sub yoke 14 is the same.

  As shown in FIG. 3A, the upper surface of the main yoke 13 and the lower surface of the sub yoke 14 are positioned parallel to each other so that the sub yoke 14 comes into contact with a predetermined position of the main yoke 13. Next, as shown in FIG. 3B, the sub yoke 14 is brought into contact with a predetermined position of the main yoke 13 and fixed so that the positional relationship between the main yoke 13 and the sub yoke 14 does not shift. Thereafter, as shown in FIG. 3C, a laser beam is irradiated toward the boundary line between the surface 13c, which is a predetermined surface of the main yoke 13, and the surface 14d of the sub yoke 14 adjacent to the surface 13c to form the welded portion 16. To do.

  Next, features of the present invention will be described.

  FIG. 4 is a diagram showing the phosphorus concentration during welding and the welding strength in the first embodiment of the present invention. The welding strength of the main yoke and the sub yoke when the plating thickness of the main yoke is 5 μm and the plating thickness of the sub yoke is 5 μm. Is shown. The phosphorus concentration in the plating shown on the horizontal axis is the phosphorus concentration in the plated portion of the sub yoke, and the welding strength shown on the vertical axis is the tensile strength of the welded portion of the main yoke and the sub yoke. The phosphorus concentration in the plated portion of the main yoke is shown as a parameter on the right side in the figure.

  According to FIG. 4, when the phosphorus concentration in the plated portion of the main yoke 13 is 0%, the weld strength between the main yoke 13 and the sub yoke 14 is highest when the phosphorus concentration in the plated portion of the sub yoke 14 is 5% or less. It is. When the phosphorus concentration in the plated portion of the main yoke 13 is 3% to 11%, the weld strength between the main yoke 13 and the sub yoke 14 is highest when the phosphorus concentration in the plated portion of the sub yoke 14 is 3% or less. It is.

  From these results, when the phosphorus concentration in the plated portion of the main yoke is 11% or less, the weld strength between the main yoke 13 and the sub yoke 14 becomes the highest because the phosphorus concentration in the plated portion of the sub yoke 14 is 3% or less. Is the time.

  FIG. 5 is a diagram showing the plating thickness and welding strength in the first embodiment of the present invention, and shows the welding strength of the main yoke and the sub yoke when the phosphorus concentration of the main yoke is 3% and the phosphorus concentration of the sub yoke is 3%. It is shown. The plating thickness shown on the horizontal axis is the plating thickness at the plating portion of the sub yoke, and the welding strength shown on the vertical axis is the tensile strength of the welding portion between the main yoke and the sub yoke. The plating thickness at the plating portion of the main yoke is shown as a parameter on the right side in the figure.

  According to FIG. 5, when the plating thickness at the plating portion of the main yoke 13 is 3 μm, the welding strength between the main yoke 13 and the sub yoke 14 is highest when the plating thickness at the plating portion of the sub yoke 14 is 1 μm to 7 μm. is there. Further, when the plating thickness at the plating portion of the main yoke 13 is 5 μm, the welding strength between the main yoke 13 and the sub yoke 14 is highest when the plating thickness at the plating portion of the sub yoke 14 is 1 μm to 5 μm. Further, when the plating thickness at the plating portion of the main yoke 13 is 7 μm to 13 μm, the welding strength between the main yoke 13 and the sub yoke 14 is highest when the plating thickness at the plating portion of the sub yoke 14 is 3 μm.

  From these results, when the plating thickness at the plating portion of the main yoke is 3 μm to 13 μm, the welding strength between the main yoke 13 and the sub yoke 14 is highest when the plating thickness at the plating portion of the sub yoke 14 is 3 μm. is there.

  FIG. 6 is a diagram showing the constituent material ratio at each position of the welded portion in the first embodiment of the present invention, FIG. 6 (a) is an enlarged view of the welded portion, and FIG. 6 (b) is the welded portion. The constituent material ratio of each position is shown. Moreover, in FIG.6 (b), a horizontal axis shows each position of a welding part, and a vertical axis | shaft shows the component ratio of a constituent material. In FIG. 6, A is a region, which indicates the component analysis portion shown in FIG.

  The welded portion 16 shown in FIG. 6A is formed by irradiating a laser beam toward the boundary between the main yoke 13 and the sub yoke 14. The main yoke 13 in FIG. 6A is covered with a plating mainly composed of nickel and phosphorus using iron as a base material, and the plated portion is formed with a plating thickness of 3 μm and a phosphorus concentration of 3%. The sub yoke 14 in FIG. 6A is also covered with a plating mainly composed of iron and nickel and phosphorus as the main yoke 13, and the plated portion is formed with a plating thickness of 3 μm and a phosphorus concentration of 3%. Has been.

  FIG. 6B shows the measurement of the constituent material ratio at each position in the region A shown in FIG. The region A is a welded portion 16 formed by irradiating a laser beam toward the boundary line between the surface 13c, which is a predetermined surface of the main yoke 13 shown in FIG. 3C, and the surface 14d of the sub yoke 14 adjacent to the surface 13c. Is part of. Further, the measurement position 30 μm shown on the horizontal axis of FIG. 6B corresponds to the detection start surface of the welded portion 16, and the measurement position 130 μm indicates the position entering 100 μm from the detection start surface of the welded portion 16.

  In FIG. 6B, the constituent ratio of the constituent materials is a constant value in the measurement position range of 30 μm to 70 μm. This is caused by irradiating the laser beam toward the boundary between the main yoke and the sub-yoke to dissolve the surface layer portion of the main yoke including the plated portion and the surface layer portion of the sub-yoke including the plated portion. That is, this is because the surface layer portion of the main yoke including the plated portion and the surface layer portion of the sub yoke including the plated portion are once dissolved and recombined at a position corresponding to a measurement position range of 30 μm to 70 μm. Therefore, the composition ratio of the constituent material constituting the welded portion 16 is shown in the measurement position range of 30 μm to 70 μm shown in FIG. 6, and specifically, composed of 90% iron, 9% nickel, and 1% phosphorus. Has been.

  As described above, the main yoke 13 that is covered with a plating containing iron and nickel and phosphorus as the main components and elastically supports the lens holder 3, and the iron and nickel and phosphorus as the main components. And the base yoke 4 formed by welding the main yoke 13 and the two sub yokes 14 and 15, and the welded portion 16 of the base 4 is made of iron. By being composed of about 90%, nickel about 9%, and phosphorus about 1%, the strength of the joint between the yokes can be secured without deforming the main yoke 13 and the sub-yokes 14 and 15. As a result, an optical pickup device that can reduce the size of the device can be realized. If the composition ratios of iron, nickel, and phosphorus are about 90%, about 9%, and about 1%, respectively, the effects of the present invention can be obtained.

  Further, as shown in FIG. 4, the main yoke 13 and the sub yokes 14 and 15 are made of iron, and the main yoke 13 and the sub yokes 14 and 15 are subjected to a plating process of about 97% nickel and a phosphorus concentration of about 3% or less. Thus, when the main yoke 13 and the sub yoke 14 are welded, another metal other than the main yoke 13 and the sub yokes 14 and 15 is not required as a welding material, and the constituent material of the joint portion between the main yoke 13 and the sub yokes 14 and 15 is used. Can be easily set to about 90% iron, about 9% nickel, and about 1% phosphorus.

  Furthermore, as shown in FIG. 5, when the main yoke 13 and the sub yokes 14 and 15 have a plating thickness of about 3 μm, the main yoke 13 and the sub yokes 14 and 15 are welded when the main yoke 13 and the sub yokes 14 and 15 are welded. It is possible to efficiently make the composition ratio of the constituent material of the joint of about 90% iron, about 9% nickel, and about 1% phosphorus.

  The present invention secures the strength of the joint portion between the yokes without deforming the first yoke and the second yoke, so that it can be applied to an optical pickup device capable of recording on or reproducing a plurality of types of optical disks. Is possible.

DESCRIPTION OF SYMBOLS 1 1st objective lens 2 2nd objective lens 3 Lens holder 4 Base 5 Suspension 6 Suspension holder 7, 8 Focus coil 9, 10, 11, 12 Focus magnet 13 Main yoke 13a, 13b Side surface 13c surface 14 Sub yoke 14a, 14b, 14c Standing portion 14d Surface 15 Sub yoke 15a, 15b, 15c Standing portion 16 Welded portion

Claims (3)

A first objective lens for condensing light from the first light source;
A second objective lens that collects light from the second light source;
A lens holder for holding the first objective lens and the second objective lens;
A focus coil fixed to the lens holder and driving the lens holder in a focus direction;
A focus magnet for applying a uniform magnetic field to the focus coil;
A first yoke that is covered with a plating containing iron as a base material and nickel and phosphorus as main components and elastically supports the lens holder;
A second yoke for supporting the focus magnet covered with a plating containing iron and nickel and phosphorus as main components;
A base formed by welding the first yoke and the two second yokes;
The welded portion of the base is composed of approximately 90% iron, approximately 9% nickel, and approximately 1% phosphorous.   2. The optical pickup device according to claim 1, wherein the first yoke and the second yoke are made of iron and plated with nickel of about 97% and a phosphorus concentration of about 3% or less.   3. The optical pickup device according to claim 2, wherein the first yoke and the second yoke have a plating thickness of about 3 [mu] m.

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