JPH1074328A - Optical pickup and disk player - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the total sum of the volume which is occupied by luminous fluxes and to reduce the device constitution by mutually intersecting plural luminous fluxes that are emitted from plural light sources and arrive at plural objective lenses arranged in accordance with the sources. SOLUTION: Optical axes of a first optical path defined by a first semiconductor laser 38 and a first objective lens 4 and a second optical path defined by a second semiconductor laser 38a and a second objective lens 5 are mutually crossed at a crossing point X. The point X is located between a beam splitter 28a and a second objective lens 5 on the first path. In the pickup, optical paths are mtutally corssed and superimposed and therefore, the total sum of the volume occupied by the fluxes is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup for writing and reading information signals on and from an optical recording medium such as an optical disk, and a disk provided with the optical pickup for recording and reproducing information signals on and from an optical disk. Belongs to the technical field related to players.

[0002]

2. Description of the Related Art Conventionally, optical recording media such as various optical disks have been proposed as recording media for information signals, and optical pickups for writing and reading information signals on and from such optical recording media have been proposed. I have. Such an optical recording medium includes a transparent substrate made of a transparent material such as polycarbonate, and a signal recording layer formed on one main surface of the transparent substrate.

As shown in FIG. 10, the optical pickup houses a semiconductor laser 103 serving as a light source in a frame (not shown), and as shown in FIG. 11, a light beam emitted from the semiconductor laser 103 is split into a beam splitter 104 and a beam splitter 104. Objective lens 10 incident via reflection mirror 105
6 and a photodetector 107 as a photodetector.

The light beam incident on the objective lens 106 is condensed and irradiated on the signal recording surface of the optical recording medium 101 by the objective lens 106. At this time, this light beam is irradiated onto the optical recording medium 101 from the transparent substrate side of the optical recording medium 101, passes through the transparent substrate, and is condensed on the signal recording surface, which is the surface of the signal recording layer. You. This objective lens 106 is always moved and supported by the biaxial actuator 108, so that a light beam is always focused on a portion of the signal recording surface where an information signal is recorded, that is, on a recording track.

[0005] When the optical recording medium is formed in a disk shape, the recording track is formed in a substantially concentric spiral shape on the main surface of the optical recording medium.

The biaxial actuator 108 is mounted on the base 10
9 has a coil bobbin 111 which is a movable part movably supported via a leaf spring 110. The objective lens 106 is mounted on the coil bobbin 111. On the base 109, a magnetic circuit including a magnet 113 and a yoke 112 is provided. A focus drive coil and a tracking drive coil are attached to the coil bobbin 111. When a drive current is supplied to the focus drive coil, the focus drive coil receives an electromagnetic force from a magnetic circuit, and moves the coil bobbin 111 to the objective lens 106 indicated by an arrow F in FIG.
In the optical axis direction, that is, the focus direction.
When a drive current is supplied to the tracking drive coil, the tracking drive coil receives an electromagnetic force from a magnetic circuit, and moves the coil bobbin 111 perpendicular to the optical axis of the objective lens 106 and the recording track indicated by an arrow T in FIG. In the tracking direction.

In the optical recording medium 106, a light beam having passed through the objective lens 106 is condensed and irradiated, so that an information signal is written or read at a position irradiated with the light beam.

The light beam irradiated on the signal recording surface is reflected by the signal recording surface with its light quantity or polarization direction modulated in accordance with the information signal recorded on the signal recording surface. Return to

The reflected light beam reflected by the signal recording surface is
The light is received by a photodetector 107 via an objective lens 106, a reflection mirror 105, and a beam splitter 104. The photodetector 107 is a light receiving element such as a photodiode, and receives a reflected light beam having passed through the objective lens 106 and converts the light beam into an electric signal. The information signal recorded on the optical recording medium 101 is reproduced based on the electric signal output from the photodetector 107.

Also, based on an electric signal output from the photodetector 107, a focus error signal indicating a distance between a focus point of a light beam by the objective lens 106 and a signal recording surface in an optical axis direction of the objective lens 106, and A tracking error signal is generated which indicates a distance on the signal recording surface between the focal point and a recording track on the signal recording surface. The biaxial actuator 108 is controlled based on the focus error signal and the tracking error signal, and the objective lens 106 is controlled so that these error signals converge to zero.
Move operation.

Meanwhile, in such an optical recording medium, the recording density of information signals has been increased to be used as an auxiliary storage device for a computer and as a recording medium for audio and image signals. .

In order to write and read information signals on an optical recording medium having a high recording density, the objective lens must have a larger NA, that is, a larger numerical aperture, and the light source of the light source must have a larger numerical aperture. It is necessary to make the emission wavelength shorter and to reduce the beam spot formed by converging the light beam on this optical recording medium.

However, when the numerical aperture of the objective lens increases, the inclination of the optical recording medium, the thickness unevenness of the transparent substrate of the optical recording medium, and the defocusing of the light beam on the optical recording medium, that is, the tolerance to defocus. Therefore, it becomes difficult to write and read information signals to and from the optical recording medium.

For example, when the optical recording medium is tilted with respect to the optical axis of the objective lens, that is, when skew occurs, a wavefront aberration occurs in the light beam condensed on the signal recording surface, and an RF signal which is an electric signal output from the photodetector is generated. Output is affected.

This wavefront aberration is equal to the numerical aperture of the objective lens, ie, 3
The third-order coma which occurs in proportion to the power and the inclination angle of the optical recording medium, that is, about the first power of the skew angle is dominant. Therefore, the permissible value for the tilt of the optical recording medium is inversely proportional to the cube of the numerical aperture of the objective lens, that is, it decreases as the numerical aperture increases.

Thickness 1.2 mm, diameter 80 mm or 12
An optical disc, which is constituted by a transparent substrate formed of a 0 mm disc-like polycarbonate and is an optical recording medium generally used widely at present, such as a so-called "compact disc", has an angle of ± 0.5 °. To ± 1 ° may occur.

In such an optical disk, the above-described wavefront aberration occurs in the light beam irradiated on the optical disk, the beam spot on the optical disk has an asymmetric shape, and intersymbol interference is remarkably generated, so that accurate signal reproduction is performed. Becomes difficult.

The amount of such third-order coma is proportional to the thickness of the transparent substrate of the optical disk. Therefore, by reducing the thickness of the transparent substrate to, for example, about 0.6 mm, the third-order coma can be reduced by half. When the coma aberration is to be reduced in this way, as an optical disc, a transparent substrate having a thickness of 1.2 mm and a transparent substrate having a thickness of 0.6 mm are used in combination. It will be.

By the way, when a parallel flat plate having a thickness t is inserted into the optical path of the convergent light beam condensed by the objective lens, t × is related to the thickness t and the numerical aperture NA of the objective lens. (NA) Spherical aberration proportional to ⁴ occurs.

The objective lens is designed to correct this spherical aberration. That is, since the amount of spherical aberration that occurs when the thickness of the transparent substrate differs, the objective lens is
It is designed to be adapted to the thickness of a predetermined transparent substrate.

An optical disk having a transparent substrate having a thickness of 1.2 mm, for example, a "compact disk", using an objective lens designed and adapted to an optical disk having a transparent substrate having a thickness of 0.6 mm, for example. When recording and reproducing information signals on a write-once optical disc or a magneto-optical disc, the difference in the thickness of these transparent substrates, for example, 0.6 mm is the thickness of the transparent substrate that the optical pickup can handle. This greatly exceeds the allowable range of the error. In this case, the objective lens cannot correct the spherical aberration generated due to the difference in the thickness of the transparent substrate, and cannot record and reproduce information signals properly.

In a so-called "CD-R" which is a write-once optical disc having a transparent substrate having a thickness of 1.2 mm, the wavelength dependency at the time of reading an information signal is high, and the recording density of the information signal is high. Information signals cannot be read using a light source whose emission wavelength has been shortened for the sake of realization. That is, the signal recording layer of the so-called “CD-R”
It is formed of an organic dye-based material, and absorbs a light beam having a shorter wavelength, for example, a light beam having a wavelength of 635 nm to 650 nm, and lowers the reflectance. The information signal cannot be read depending on the light flux.

Conventionally, as shown in FIG. 12, a first biaxial actuator 108 for supporting a first objective lens 106 on which a light beam emitted from a first semiconductor laser 103 is incident, and a second semiconductor An optical pickup having a second biaxial actuator 120 that supports a second objective lens 118 on which a light beam emitted from a laser 115 is incident has been proposed. Each semiconductor laser 103,
115 and the biaxial actuators 108 and 120 are arranged on the same frame 114.

The light beam emitted from the first semiconductor laser 103 passes through a first beam splitter 104 and a first reflecting mirror 105 and is incident on a first objective lens 106. Further, the light beam emitted from the second semiconductor laser 115 is incident on the second objective lens 118 via the second beam splitter 116 and the second reflection mirror 117. The first and second objective lenses 106 and 118 have their optical axes parallel to each other.

First and second biaxial actuators 10
Reference numerals 8 and 120 have coil bobbins 111 and 123, which are movable portions supported by base portions 109 and 121 via leaf springs 110 and 122, respectively.
Each of the objective lenses 106 and 118 includes a coil bobbin 111,
123. The magnets 113 and 125 and the yoke 1 are provided on the bases 109 and 121, respectively.
A magnetic circuit consisting of 12, 124 is provided. A focus drive coil and a tracking drive coil are attached to the coil bobbins 111 and 123, respectively. When a drive current is supplied to the focus drive coil, the focus drive coil receives an electromagnetic force from a magnetic circuit and moves the coil bobbins 111 and 123 in the optical axis direction of the objective lenses 106 and 118, that is, in the focus direction. . When a drive current is supplied to the tracking drive coil, the tracking drive coil receives an electromagnetic force from a magnetic circuit, and the coil bobbin 111,
Reference numeral 123 denotes an objective lens 106, 1 indicated by an arrow T in FIG.
18 in a direction perpendicular to the optical axis and the recording track, that is, in the tracking direction.

The light beam emitted from the first semiconductor laser 103 and the light beam emitted from the second semiconductor laser 115 have different wavelengths. Further, the first and second objective lenses 106 and 115 have different numerical apertures.

In a disk player provided with this optical pickup, a first type optical disk 101 having a transparent substrate thickness of, for example, 0.6 mm or a second type optical disk 101 having a transparent substrate thickness of, for example, 1.2 mm The optical disk is held and rotated by a disk table having a central portion mounted on a drive shaft of a spindle motor (not shown). The optical pickup is supported by a guide shaft so as to be movable in the axial direction of the guide shaft as shown by an arrow T in FIG. The optical pickup is moved in the radial direction of the optical disk held on the disk table.

In this optical pickup, when the first type of optical disk 101 is mounted on the disk table, the first semiconductor laser 103 is turned on and the first type of optical disk 101 is turned on.
The first type optical disc 1 via the objective lens 106
01 for writing and reading information signals
When a second type of optical disk is mounted on the disk table, the second semiconductor laser 115 is turned on to write and read information signals to and from the second type of optical disk via the second objective lens 118. .

First and second biaxial actuators 10
Numerals 8 and 120 move the objective lenses 106 and 118 in a focus direction which is an optical axis direction of the objective lenses 106 and 118 and a tracking direction indicated by an arrow T in FIG. 12 which is a direction parallel to the axial direction of the guide shaft. By operating, the objective lenses 106 and 118 follow the recording tracks on the optical disk 101.

[0030]

As described above, in an optical pickup having two semiconductor lasers, two-axis actuators, and two objective lenses, each serving as a light source, the frame 114 has a structure shown in FIG. As indicated by the arrow w, in particular, each objective lens 106, 118
Becomes large in the arrangement direction. This is because each optical path leading to each objective lens 106, 118 has its own occupied volume, that is, the frame 114 is large enough to include at least the total volume occupied by each optical path. It is necessary to have

Accordingly, the present invention has been proposed in view of the above-mentioned circumstances, and a plurality of optical signal recording / reproducing media having different thicknesses of transparent substrates are provided so that information signals can be written and read satisfactorily. An object of the present invention is to provide an optical pickup including a light source and a plurality of objective lenses, the optical pickup having a reduced device configuration.

Another object of the present invention is to solve the problem of providing a disk player which is provided with the optical pickup according to the present invention and whose apparatus configuration is reduced in size.

[0033]

In order to solve the above-mentioned problems, an optical pickup according to the present invention comprises a plurality of light sources,
A plurality of objective lenses are provided with their optical axes parallel to each other corresponding to the plurality of light sources, and receive a light beam emitted from one corresponding light source, and a plurality of objective lenses from each light source to each objective lens. One or a plurality of deflecting optical elements arranged on the optical path excluding at most one of the optical paths and deflecting the optical path; and a direction parallel to the optical axis of these objective lenses and the optical axis. And one or more biaxial actuators that are movably supported in a direction perpendicular to the optical path, and that the plurality of optical paths intersect with each other.

Further, the disc player according to the present invention
A rotation operation mechanism that supports and rotates the optical disk, a plurality of light sources, and a light beam emitted from one corresponding light source that is disposed with the optical axis parallel to each other corresponding to the plurality of light sources. A plurality of objective lenses for condensing a light beam on a signal recording surface of an optical disk supported by the rotation operation mechanism; and One or a plurality of deflecting optical elements arranged and deflecting the optical path, and each objective lens can be moved in a direction parallel to the optical axis of these objective lenses and in a radial direction of the optical disk supported by the rotation operation mechanism. One or a plurality of biaxial actuators supported by the rotary operation mechanism, and detects one of the plurality of light sources according to the detected type of the optical disc supported by the rotation operation mechanism. And control means for turning on the 択的, a plurality of optical paths, some were made and that they are crossing each other.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in the following order with reference to the drawings.

[1] Type of optical recording medium [2] Support of optical pickup [3] Configuration of biaxial actuator (objective lens driving device) [4] Plurality of optical paths [5] Configuration of disk player [6] Plural Other examples of light paths

[1] Type of Optical Recording Medium In this embodiment, an optical pickup and a disk player according to the present invention are used as shown in FIGS. A laser beam is applied to both a first type optical disc 101 which is an optical recording medium and a second type optical disc 102 which is a disc-shaped optical recording medium having a transparent substrate thickness of 1.2 mm. Thus, the optical pickup and the disc player are configured to write and read information signals.

The first type optical disc 101 has a thickness of 0.1 mm.
It has a transparent substrate formed of a disc-shaped polycarbonate having a diameter of 6 mm and a diameter of 120 mm, and a signal recording layer formed on one main surface of the transparent substrate. This first type optical disk 101 is obtained by bonding two first type optical disks 101 together on the signal recording layer side.
A disk having a thickness of 1.2 mm, that is, a double-sided optical disk or a multilayer optical disk is formed.

This first type of optical disk 101 is
The laser beam having a wavelength of 635 nm (or 650 nm) is used to write and read information signals through an objective lens having a numerical aperture (NA) of 0.6. In the signal recording layer, the information signal is recorded along a substantially concentric spiral recording track.

As the optical disc 101 of the first type, for example, a so-called “digital
A "video disc (DVD)" (trade name) has been proposed.

The second type optical disc 102 has a thickness of 1.
It has a transparent substrate formed of a disc-shaped polycarbonate having a diameter of 2 mm, a diameter of 80 mm or 120 mm, and a signal recording layer formed on one main surface of the transparent substrate.

The second type of optical disc 102 is
The information signal is written and read by a laser beam having a wavelength of 780 nm through an objective lens having a numerical aperture of 0.45. In the signal recording layer, the information signal is recorded along a substantially concentric spiral recording track.

Examples of the optical disk 102 of the second type include a so-called “compact disk (CD)” (trade name) and a so-called “CD-R”.
OM "and" CD-R "have been proposed.

As shown in FIG. 5, the first or second type optical discs 101 and 102 are used in a disc player provided with an optical pickup according to the present invention, as shown in FIG.
The rotary operation is performed by a spindle motor 17 mounted on a chassis and constituting a rotary operation mechanism. A disk table 40 constituting a rotation operation mechanism is attached to a drive shaft 42 of the spindle motor 17. The disk table 40 is formed in a substantially disk shape, and has a substantially frustoconical projection 41 at the center of the upper surface. When the central portion of each of the optical disks 101 and 102 is placed on the disk table 40, the projection 41 is fitted into a chucking hole 103 provided in the central portion of the optical disks 101 and 102. It is configured to hold the central portion of That is, the optical disk 10
The center portions 1 and 102 are held on the disk table 40, and are rotated together with the disk table 40 by the spindle motor 17.

[2] Support of Optical Pickup As shown in FIG. 2, the optical pickup has a frame 1 movably supported by a guide shaft 18 and a support shaft 19 arranged on a chassis. You. The guide shaft 18 and the support shaft 19 are arranged parallel to each other, and are arranged parallel to the upper surface of the disk table 40.

As shown in FIG. 1, the frame 1 has a guide hole 13 through which a guide shaft 18 is inserted, and a support groove 15 into which a support shaft 19 is inserted. The frame 1 includes a guide shaft 18 and a support shaft 19.
The optical disk 101, 102 mounted on the disk table 40 has its upper surface portion
In the state where the optical disks 101 and 10 are opposed to the spindle motor 17,
2 in the radial direction. The frame 1 is moved by a sled motor provided on a chassis.

The frame 1 and the spindle motor 17
, That is, the frame 1 and the optical disc 1
The positional relationship between the frame 1 and the frame 102 may be changed by moving the frame 1 with the spindle motor 17 fixed, and conversely, the position may be changed by moving the spindle motor 17 with the frame 1 fixed. Alternatively, both of the frame 1 and the spindle motor 17 may be changed by performing a moving operation.

[3] Configuration of Biaxial Actuator (Objective Lens Driving Device) By the way, the transparent substrates of the optical discs 101 and 102 are formed in the shape of a flat plate, but may have a slight distortion. When the disk is held on the disk table and rotated, so-called surface run-out occurs. That is, the signal recording layers of the optical discs 101 and 102 are periodically moved in the direction of coming and going with respect to the optical pickup when the optical discs 101 and 102 are rotated while their center portions are held. Also, the optical discs 101 and 10
The recording track of No. 2 is formed so that the center of curvature coincides with the center of the transparent substrate, but may have a slight eccentricity. Therefore, when the transparent substrate is rotated while the central portion is held. The optical disks 101 and 102 periodically move in the radial direction.

In order to make a laser beam for writing and reading information signals to and from these optical discs 101 and 102 follow the movement of the recording track due to the surface deflection or eccentricity of such optical discs 101 and 102, the optical pickup is used. , As shown in FIGS. 4 and 7,
First and second biaxial actuators 2 and 3 are provided. These biaxial actuators 2 and 3 are mounted on the upper surface of the frame 1.

The first biaxial actuator 2 moves the first objective lens 4 in the direction of the optical axis of the first objective lens 4, that is, in the focus direction indicated by the arrow F in FIGS. , That is, the arrow T _{1 in} FIG.
7 so as to be movable in a tracking direction indicated by an arrow T in FIG. The first objective lens 4 has a numerical aperture of 0.6.

The second biaxial actuator 3 moves the second objective lens 5 in the optical axis direction of the second objective lens 5, that is, in the focus direction indicated by an arrow F in FIGS. direction perpendicular to the optical axis, i.e., moving operably supported in the tracking direction indicated by arrow in FIG. 1 T ₂ and 7 in the arrow T. The second objective lens 5 has a numerical aperture of 0.45.

The objective lenses 4 and 5 are opposed to the signal recording layers of the optical discs 101 and 102 mounted on the disc table 40, and the frame 1 is moved along the guide shaft so as to be shown in FIG. As indicated by the middle arrow T, the optical disk 101 and 102 are moved along the inner and outer peripheries. The first and second objective lenses 4 and 5 are arranged in a direction substantially perpendicular to the longitudinal direction of the guide shaft, that is, in the circumferential direction of the optical disks 101 and 102 mounted on the disk table. The first and second objective lenses 4 and 5 are supported with their optical axes parallel to each other.

The biaxial actuators 2 and 3 are respectively mounted on bases 23 and 2 fixedly mounted on the frame 1.
Five. The two-axis actuators 2 and 3 have coil bobbins 2b and 3b which are movable parts to which the objective lenses 4 and 5 are attached. The coil bobbins 2b and 3b are formed in a frame shape from a synthetic resin material, and an objective lens mounting hole into which the objective lenses 4 and 5 are fitted is provided in a front end portion. The objective lenses 4 and 5 are fitted and attached to the objective lens mounting holes from above. These coil bobbins 2b, 3b
A pair of leaf spring members 2 which are elastic members
a, 3a, it is supported by the upper base parts 23, 25.

The leaf spring members 2a, 3a are formed in a thin and elongated plate shape from a metal material having appropriate elasticity such as phosphor bronze. These leaf spring members 2a, 3a
The coil bobbins 2b, 3b are supported substantially displaceably with respect to the bases 23, 25.

The coil bobbins 2b and 3b have
A focus drive coil and a tracking drive coil are mounted. The focus drive coil is wound around side surfaces (outer peripheral portions) of the coil bobbins 2b and 3b, and the center axis of the coil is made parallel to the optical axes of the objective lenses 4 and 5. The tracking drive coil is wound in a substantially annular shape, and is attached to the end surface of the coil bobbin 2b, 3b. In this tracking drive coil, the center axis of the coil is parallel to each of the leaf spring members 2a, 3a, and the center axis is in a direction orthogonal to the optical axes of the objective lenses 4, 5.

On the bases 23 and 25, a magnetic circuit comprising magnets 54 and 54 and yokes 24 and 26 is provided. Each of the yokes 24 and 26 is formed of a magnetic material (high magnetic permeability material) such as iron. The yokes 24, 26 are inserted from below into hollow portions in the coil bobbins 2b, 3b, and are located near the tracking drive coil. Magnets 54, 54 are attached to the front surfaces of the yokes 24, 26 by bonding using an adhesive.

In the first biaxial actuator 2,
The first objective lens 4 moves in the optical axis direction of the first objective lens 4, that is, the focus direction indicated by an arrow F in FIG.
And a direction perpendicular to the optical axis, that is, an arrow T in FIG.
Are supported so as to be movable in two directions of the tracking direction shown by the arrow, and are moved and operated in the two directions by the electromagnetic force generated between each drive coil and the magnet 54.

In the second biaxial actuator 3, the second objective lens 5 is connected to the second objective lens 5.
8, that is, a focus direction indicated by an arrow F in FIG. 8 and a direction orthogonal to the optical axis, that is, a tracking direction indicated by an arrow T in FIG. , Each drive coil and magnet 5
It is moved in the two directions by the electromagnetic force generated between the four.

The structure of these two-axis actuators 2 and 3 will be described in more detail. As shown in FIG. 6, these two-axis actuators 2 and 3 are composed of a coil bobbin main body serving as a movable part to which objective lenses 4 and 5 are attached. 69. The coil bobbin main body 69 is formed of a synthetic resin material in a frame shape, and has an objective lens mounting hole 70 in which the objective lenses 4 and 5 are fitted at the front end portion. The objective lenses 4 and 5 are fitted and mounted in the objective lens mounting holes 70 from above. The coil bobbin main body 69 has both side portions supported by the upper fixed block 59 via a pair of leaf springs 65 and 66 serving as elastic members.

The leaf springs 65 and 66 are integrally formed in a thin and elongated plate shape using a suitable elastic metal material such as phosphor bronze. These coil bobbin main body 6
9 and the upper fixed block 59 and the leaf springs 65 and 66 are formed by so-called outsert molding.
The distal end portion and the proximal end portion of the fifth and 66 are connected so as to be buried inside the coil bobbin body 69 and the upper fixed block 59. The base end portions of the leaf springs 65 and 66 protrude rearward from the rear end surface of the upper fixed block 59 as connection terminals. The distal ends of the leaf springs 65 and 66 are connected to a terminal plate embedded in the coil bobbin main body 69 and having a rear end protruding rearward as a connection terminal 81 from a rear end surface of the coil bobbin main body 69. ing.

A bobbin support frame 64 is attached to the lower surface of the coil bobbin main body 69. The bobbin support frame 64 is formed of the same material as the coil bobbin main body 69 in a frame shape that supports both side portions of the coil bobbin main body 69. The bobbin support frame 64 is provided with a pair of positioning projections 83, 83 projecting from the upper surface thereof. It is adhered and fixed by an agent. The bobbin support frame 64 has both side portions via a pair of leaf springs 60 and 61 serving as leaf spring members 2a and 3a.
It is supported by the lower fixed block 58.

The leaf springs 60 and 61 are integrally formed in a thin and elongated plate shape from a metal material having appropriate elasticity such as phosphor bronze. The bobbin support frame 64, the lower fixed block 58, and the leaf springs 60, 61 are formed by so-called outsert molding, so that the distal end portion and the base end portion of each of the leaf springs 60, 61 have the bobbin support frame 64 and the It is connected while being buried inside the lower fixed block 58. The base end portions of these leaf springs 60 and 61 protrude rearward from the rear end surface of the lower fixed block 58 as connection terminals. The distal end portions of the leaf springs 60 and 61 are embedded in the bobbin support frame 64, and the rear end of the distal end portion protrudes rearward as the connection terminal 81 from the rear end surface of the bobbin support frame 64. Connected to the terminal board.

The lower fixed block 58 and the upper fixed block 59 are fixedly disposed on the objective lens driving mechanism support plate 23 and the yoke 25 via the fixed plate 56. That is, the lower fixing block 58 is fixed on the fixing plate 56 by bonding with an adhesive.
The upper fixing block 59 is fixed thereon by bonding with an adhesive, and the fixing plate 56 is further bonded to the objective lens driving mechanism support plate 23 and the yoke 25 with an adhesive or fixed by soldering. Thus, a fixed portion is configured. Positioning projections 57 for projecting the lower fixed block 58 are provided on both sides of the fixed plate 56. A positioning protrusion 82 for positioning the upper fixed block 59 is provided on the upper surface of the lower fixed block 58.

Each of the leaf springs 60, 61, 65, and 66 has a linear portion and crank portions 62, 63, 67, and 68, respectively, and has a base end attached to a fixed portion including fixed blocks 58 and 59. The distal end is attached to the coil bobbin main body 69 or the bobbin support frame 64. The leaf springs 60, 61, 65, 66 make the respective linear portions substantially parallel to each other, and the coil bobbin main body 69 and the bobbin support
4 is supported displaceably with respect to the fixed part.

Then, the crank portions 62, 63, 67, 6
Numeral 8 is provided at the base end portion of each of the leaf springs 60, 61, 65, 66, and is formed to have two 90 ° bent portions in mutually opposite directions. In addition, these leaf springs 60, 6
1, 65, 66, the crank portions 62, 63, 6
A displacement restricting piece 78 is provided so as to surround both the base end side and the halfway part of each of the parts 7 and 68.

A coil winding 72 is attached to the bobbin support frame 64 and the coil bobbin main body 69. The coil winding part 72 is formed in a hollow quadrangular prism shape whose upper side and lower side are open. The coil winding portion 72 is fitted in a through hole provided substantially in the center of the coil bobbin main body 69 and the bobbin support frame 64, and a pair of projecting protrusions provided on the upper surface of the bobbin support frame 64. Are fixed to the coil bobbin main body 69 and the bobbin support frame 64 with an adhesive.

A focus coil 73 and tracking coils 74, 74 are attached to the coil winding section 72. The focus coil 73 is wound around a side surface portion (outer peripheral portion) of the coil winding portion 72, and has a center axis of the coil parallel to the optical axes of the objective lenses 4 and 5. The tracking coils 74, 74 are wound around tracking coil bobbins 75, 75, respectively. The tracking coils bobbins 75, 75 are attached to the front end surface of the coil winding section 72, whereby the coil winding section 7 is wound.
2 attached. These tracking coils 7
4, 74 make the central axes of the coils parallel to each other, make the central axes parallel to the linear portions of the leaf springs 60, 61, 65, 66, and set the central axes to the optical axes of the objective lenses 4, 5. The direction is orthogonal to.

The lead wires at the beginning and end of winding of each of the coils 73, 74, 74 correspond to the four terminal rods 80, 80, 80, 80 projecting rearward from the coil winding part 72. It is connected. And these terminal rods 80, 80,
Reference numerals 80, 80 denote connection terminals 81, 81, of terminal plates embedded in the coil bobbin main body 69 and the bobbin support frame 64, respectively, protruding rearward from rear end surfaces of the coil bobbin main body 69 and the bobbin support frame 64. 81 and 81 are connected by soldering.

Coil bobbin main body 69, bobbin support frame 6
The coil bobbin 4 and the coil winding section 72 constitute the coil bobbins 2 b and 3 b of the biaxial actuators 2 and 3.

Then, a pair of front and rear yokes 24, 24, 24 are provided on the objective lens driving mechanism support plate 23 and the yoke portion 25.
Reference numerals 26 and 26 stand upright with respect to the objective lens drive mechanism support plate 23 and the yoke 25. The objective lens driving mechanism support plate 23, the yoke 25, and the yokes 24, 24, 26, 26 are formed of a magnetic material (high magnetic permeability material) such as iron. The rear yoke 24,
26 is inserted into the hollow portion in the coil winding portion 72 from below. A magnet 54 is attached to the front surfaces of the rear yokes 24 and 26 by bonding using an adhesive. The front yokes 24, 26 are inserted from below into the through holes at the center of the bobbin support frame 64 and the coil bobbin main body 69, and are in front of the coil winding portion 72, that is, in front of the tracking coils 74, 74. Located on the side. The upper ends of the yokes 24, 24, 26, 26 are connected to each other via a connecting plate 55. This continuous plate 55 is attached to each of the yokes 24, 24, 26,
Similarly to 26, it is formed of a magnetic material (high magnetic permeability material) such as iron.

In the first biaxial actuator 2,
The first objective lens 4 has an optical axis direction of the first objective lens 4, that is, a focus direction indicated by an arrow F in FIG.
And a direction perpendicular to the optical axis, that is, an arrow T in FIG.
It is supported so as to be movable in two directions of a first tracking direction indicated by ₁ and is moved in the two directions by the electromagnetic force generated between the coils 73, 74, 74 and the magnet.

Further, in the second biaxial actuator 3, the second objective lens 5 is
1, that is, a focus direction indicated by an arrow F in FIG. 6 and a direction orthogonal to the optical axis, ie, a second tracking direction indicated by an arrow T ₂ in FIG. And the coils 73, 74,
Due to the electromagnetic force generated between the magnet 74 and the magnet 54.
Moved in the direction.

As described above, the recording tracks are formed substantially concentrically on the optical discs 101 and 102 in a spiral shape on the signal recording layer.
In this optical disc, an information signal is written along a recording track. These two-axis actuators 2, 3
Moves the objective lenses 4 and 5 in order to make the objective lenses 4 and 5 follow the displacement of the optical disks 101 and 102. That is, the optical pickup always focuses the light flux transmitted through the objective lenses 4 and 5 at the position where the information signal is written on the signal recording layer of the optical disk.

This optical pickup is opposed to the optical disks 101 and 102 held on the disk table 40 in the chucking holes 103 and rotated by the spindle motor 17.
By performing the movement operation in the radial direction 02, the information signal is written or read to or from the recording track while being moved along the recording track relative to the optical disks 101 and 102. Therefore, in this optical pickup, the focus position of the laser beam by the objective lenses 4 and 5 must follow the displacement of the position of the recording track due to the surface deflection and eccentricity of the optical disk. Therefore, each biaxial actuator 2, 3
The objective lenses 4 and 5 are moved in the focus direction and the tracking direction.

In these two-axis actuators 2 and 3, when the focus drive current is supplied to the focus drive coil, the coil bobbins 2b and 3b are operated to move in the focus direction as shown by the arrow F in FIG. . Further, in these two-axis actuators 2 and 3, when a tracking drive current is supplied to the tracking drive coil, the coil bobbins 2b and 3b are operated to move in the tracking direction as indicated by an arrow T in FIG.

In these two-axis actuators, the focus drive current and the tracking drive current are error signals (focus error signal and tracking error signal) indicating the amount of deviation between the focus position of the laser beam by the objective lenses 4 and 5 and the recording track. Supplied based on Therefore, these two-axis actuators 2 and 3 perform a periodic movement operation on the objective lenses 4 and 5 in synchronization with the rotation cycle of the optical disks 101 and 102.

The laser beam focused on the signal recording layer is
In the signal recording layer, the reflection intensity or the polarization direction is modulated according to the information signal written in the signal recording layer, and reflected. The reflected light fluxes reflected by the signal recording layer return to the objective lenses 4 and 5, respectively, and are received by the photodetectors disposed in the frame 1 through the objective lenses 4 and 5 as described later. This photodetector has a plurality of photodetectors.
From the output signal from this photodetector, the optical disk 10
A read signal, a focus error signal, and a tracking error signal of the information signals from 1, 102 are generated.

[4] Plural Optical Paths As shown in FIG. 5, a light emitting and receiving composite element having a semiconductor laser 38 serving as a first light source and a semiconductor laser chip serving as a second light source, ie, as shown in FIG. A laser coupler 33 is built in. The semiconductor laser chip of the semiconductor laser 38 and the semiconductor laser chip of the laser coupler 33 emit first and second laser beams, respectively, which are linearly polarized coherent lights. These laser beams are divergent beams. The wavelength of the first laser beam emitted from the semiconductor laser 38 is 635 nm or 650 nm, which is the first wavelength. The wavelength of the second laser beam emitted from the semiconductor laser chip of the laser coupler 33 is 780 nm, which is the second wavelength.
It is.

The semiconductor laser 38 is connected to a high-frequency module substrate 37. This high frequency module substrate 37
Is provided with a high-frequency circuit for driving the semiconductor laser 38 at a high frequency of about 300 mHz to 400 MHz in order to prevent the occurrence of return light noise in the semiconductor laser 38.

Further, as shown in FIG. 4, the semiconductor laser 38 is fitted into a mounting hole provided in the frame 1 and is fixed to the frame 1.
As shown in FIG. 5, the first laser beam emitted from the semiconductor laser 38 passes through a diffraction grating, that is, a grating 39, and then enters the flat beam splitter 28. The grating 39 converts the first laser beam into
The laser beam is split into three laser beams of zero-order light and ± first-order light.
The beam splitter 28 is disposed such that its main surface is at an angle of 45 ° to the optical axis of the first laser beam. The beam splitter 28 transmits part of the first laser beam, but reflects the rest. The first laser beam reflected by the beam splitter 28 is incident on a collimator lens 29, and is converted into a first parallel laser beam by the collimator lens 29.

The first parallel laser beam passing through the collimator lens 29 is reflected by the first reflecting mirror 30 and
The light is deflected by 0 ° and is incident on the first objective lens 4. The first objective lens 4 transmits the first parallel laser beam to the first
The light is focused on the signal recording layer of the optical disc 101 of the type.

The first laser beam condensed on the signal recording layer of the first type optical disc 101 is reflected by this signal recording layer, and the first objective lens 4, the first reflection mirror 30, the collimator lens After passing through 29, the light passes through the beam splitter 28 and is received by the photodetector 32.

The laser coupler 33 includes a semiconductor laser chip and first and second photodetectors disposed on the same semiconductor base. The semiconductor laser chip is disposed on the semiconductor base via a heat sink.
Each photodetector is formed on the semiconductor substrate in a state of being divided into a plurality of light receiving surfaces.

In the laser coupler 33, a beam splitter prism is disposed on each photodetector. In the beam splitter prism, the beam splitter surface, which is a slope having a predetermined inclination angle with respect to the upper surface of the semiconductor substrate, is directed toward the semiconductor laser chip.

In this laser coupler 33, the semiconductor laser chip emits a second laser beam toward the beam splitter surface. The second laser beam emitted from the semiconductor laser chip is reflected by the beam splitter surface and emitted vertically upward with respect to the semiconductor substrate.

The second laser beam emitted from the laser coupler 33 is reflected by the bending mirror
The light is deflected by 0 °, further reflected by the second reflection mirror 34 and deflected by 90 °, and is incident on the second objective lens 5. The second laser light beam incident on the second objective lens 5 passes through the transparent substrate of the second type optical disk 102 by the second objective lens 5 to record a signal on the second type optical disk 102. It is focused on the surface of the layer.

The second laser beam condensed on the signal recording layer of the second type optical disc 102 is reflected by this signal recording layer, and is reflected by the second objective lens 5, the second reflecting mirror 34, and the bending. After passing through the mirror 10, the laser coupler 33
Is received by the photodetector.

In this optical pickup, the first optical path from the semiconductor laser 38 to the first objective lens 4 and the second optical path from the laser chip of the laser coupler 33 to the second objective lens 5 are: In frame 1, they cross each other at intersections. This intersection is the first
Is located between the collimator lens 29 and the first reflection mirror 30. The intersection is located between the bending mirror 10 and the second reflection mirror 34 on the second optical path. That is, the intersection of the first and second optical paths is located at a portion of these optical paths that is perpendicular to the optical axis of each of the objective lenses 4 and 5.
In this optical pickup, since the optical paths intersect each other, the total volume occupied by these optical paths is reduced by the overlap of the optical paths.

In this optical pickup, as shown in FIGS. 7 and 8, a first semiconductor laser 38 serving as a first light source and a second semiconductor laser serving as a second light source are provided in the frame 1. 38a may be incorporated. Each of the semiconductor lasers 38 and 38a emits first and second laser beams, which are coherent linearly polarized lights. These laser beams are divergent beams. The wavelength of the first laser beam emitted from the first semiconductor laser 38 is 635 nm or 650 nm, which is the first wavelength. The wavelength of the second laser beam emitted from the second semiconductor laser 38a is 780 nm, which is the second wavelength.

The first laser beam emitted from the first semiconductor laser 38 passes through a grating (not shown),
The light enters the flat beam splitter 28. The grating divides the first laser beam into 0-order light and ± 1st-order light.
The laser beam is branched into a book. Beam splitter 28
Are arranged such that the main surface is at an angle of 45 ° to the optical axis of the first laser beam. This beam splitter 2
8 transmits part of the first laser beam, but reflects the rest. The first laser beam reflected by the beam splitter 28 is reflected by the first reflecting mirror 30 and is deflected by 90 °, and is outside the frame 1 through a through hole provided on the upper surface of the frame 1. It is injected to one side. Then, the first laser beam is incident on the first objective lens 4 supported by the first biaxial actuator 2. The first objective lens 4 focuses the first laser beam on the signal recording layer of the first type optical disc 101.

The first laser beam reflected on the surface of the signal recording layer of the first type optical disc 101 is the first laser beam.
Through the objective lens 4 and the beam splitter 28 of
The light is received by the first photodetector 32.

The second laser beam emitted from the second semiconductor laser 38a is incident on a flat beam splitter 28a. The beam splitter 28a is disposed such that its main surface is at an angle of 45 ° with respect to the optical axis of the second laser beam. This beam splitter 28a
Transmits part of the second laser beam, but reflects the rest. The second laser light flux reflected by the beam splitter 28a is reflected by the second reflection mirror 34 and deflected by 90 °, and passes through the through-hole provided on the upper surface of the frame 1 so as to be outside the frame 1. It is injected to one side. Then, the second laser beam is incident on the second objective lens 5 supported by the second biaxial actuator 3. The second objective lens 5 focuses the second laser beam on the signal recording layer of the second type optical disc 102.

The second laser beam reflected on the surface of the signal recording layer of the second type optical disc 102 is the second laser beam.
Through the objective lens 5 and the beam splitter 28a, and is received by the second photodetector 32a.

The first optical path from the first semiconductor laser 38 to the first objective lens 4 and the second optical path from the second semiconductor laser 38a to the second objective lens 5 The optical axes cross each other at the intersection X. This intersection X is located between the beam splitter 28 and the first reflection mirror 30 on the first optical path. As shown in FIG. 8, the first reflection mirror 30
The laser beam is deflected to enter the first objective lens 4. The intersection X is located between the beam splitter 28a and the second reflection mirror 34 on the second optical path. Second reflection mirror 34
8 is for deflecting the second laser beam and making it incident on the second objective lens 5, as shown in FIG.

In this optical pickup, since the optical paths intersect each other, the total volume occupied by these optical paths is reduced by the overlap of the optical paths. Therefore, in this optical pickup, the size of the frame 1 in the direction of arrangement of the objective lenses 4 and 5 indicated by the arrow W in FIG. 7 can be reduced.

[5] Configuration of Disc Player The disc player according to the present invention is provided with a control circuit serving as control means for determining the type of the optical disk mounted on the disk table. The control circuit controls turning on and off of each of the semiconductor lasers 38 and 38a or the semiconductor laser chip of the laser coupler 33. Further, a signal output from the optical pickup is sent to this control circuit. The control circuit controls each of the semiconductor lasers 38 and 38 according to various signals to be sent.
a, each two-axis actuator 2, 3, spindle motor 1
7 and the sled motor.

When it is determined that the first type of optical disk 101 is mounted on the disk table 40, the control circuit causes the first semiconductor laser 38 to emit light and the semiconductor laser of the laser coupler 33 to emit light. Chips or
The second semiconductor laser 38a is extinguished. At this time, the first laser beam that has passed through the first objective lens 4 is irradiated onto the first type optical disc 101 from the transparent substrate side of the first type optical disc 101, passes through the transparent substrate, and The light is focused on the signal recording layer. First objective lens 4
Is moved by the first biaxial actuator 2 in the optical axis direction of the first objective lens 4 and in the direction orthogonal to the optical axis. The first objective lens 4 is moved and operated by the first biaxial actuator 2 following the displacement of the first type of optical disc 101 in the direction of the optical axis of the first objective lens 4 (so-called surface deflection). As a result, the focal point of the laser beam is always positioned on the signal recording layer. Also,
The first objective lens 4 is moved by the first biaxial actuator 2 by following the displacement of the recording track of the first type optical disc 101 in the direction perpendicular to the optical axis of the first objective lens 4. As a result, the focal point of the first laser beam is always positioned on the recording track.

This optical pickup writes and reads information signals to and from the signal recording layer of the first type optical disk 101 by condensing and irradiating the first laser beam onto the signal recording layer. In writing the information signal, if the first type optical disk 101 is a magneto-optical disk, the magneto-optical disk is irradiated with the first laser beam and the irradiation position of the first laser beam. Is applied with an external magnetic field. By modulating either the optical output of the first laser beam or the intensity of the external magnetic field according to the information signal to be recorded, the information signal is written to the magneto-optical disk. When the first type optical disk 101 is a phase change type disk, the optical output of the first laser beam is modulated according to the information signal to be recorded, thereby writing the information signal to the phase change type disk. Is performed.

In this optical pickup, the first type optical disc 101 has the first type on the signal recording layer.
The laser beam is condensed and irradiated, and the reflected light beam of the laser beam by the signal recording layer is detected, so that an information signal is read from the signal recording layer.

In reading the information signal, if the first type of optical disk 101 is a magneto-optical disk, the change in the polarization direction of the reflected light beam is detected to detect the change.
An information signal is read from the magneto-optical disk.
When the first type optical disk 101 is a phase change type disk or a so-called pit disk,
By detecting a change in the amount of reflected light of the reflected light flux, an information signal is read from the phase change type disk.

That is, the first light focused on the signal recording layer
Is reflected by the signal recording layer and returns to the first objective lens 4 as a reflected light beam. The reflected light flux returning to the first objective lens 4 is
And returns to the first beam splitter 28 via the first reflection mirror 30. The reflected light flux returning to the first beam splitter 28 is transmitted through the first beam splitter 28, is branched to an optical path returning to the first semiconductor laser 38, and is transmitted to the first photodetector 32. Heading.

Since the first beam splitter 28 is a parallel flat plate inclined at an angle of 45 ° with respect to the optical axis of the reflected light beam, it generates astigmatism in the reflected light beam. By detecting the direction and amount of this astigmatism,
A focus error signal is generated. The focus error signal is generated between the focal point of the first laser beam by the first objective lens 4 and the surface of the signal recording layer of the first type optical disc 101 in the optical axis direction of the first objective lens 4. This is a signal indicating the amount and direction of the positional shift. Further, a tracking error signal is generated based on the detection output of the first photodetector 32. The tracking error signal is a position between the focal point of the first laser beam by the first objective lens 4 and the recording track of the first type of optical disc 101 in the direction orthogonal to the optical axis of the first objective lens 4. It is a signal indicating the amount and direction of the displacement. The first biaxial actuator 2 is driven based on the focus error signal and the tracking error signal.

When the first type optical disk 101 is a magneto-optical disk, the first beam splitter 2
Is incident on the first photodetector 32 via a Wollaston prism (not shown). The Wollaston prism converts the reflected light beam into a first polarized light component that is polarized in the polarization direction of the reflected light beam, and a second polarized light component that is polarized in a direction of + 45 ° with respect to the polarization direction of the reflected light beam. The reflected light flux is split into three light fluxes with a third polarization component that is polarized in a direction of −45 ° with respect to the polarization direction of the reflected light flux.

In this case, the first photodetector 32 includes a plurality of photodiodes corresponding to a plurality of light beams split by the Wollaston prism, and converts each of the light beams into a corresponding photo-diode. The light is received by a diode. By arithmetically processing the light detection output from each photodiode of the first photodetector 32, a read signal of the information signal recorded on the magneto-optical disk is generated.

The optical pickup is moved along the guide shaft 18 and the support shaft 19 so that the first objective lens 4 faces the entire area of the signal recording area of the first type optical disc 101. By performing the moving operation, the information signal can be written and read for the entire signal recording area. That is, the optical pickup is moved over the inner and outer peripheries of the first type optical disk 101, and the first type optical disk 101 is rotated to operate the optical pickup 101 to record signals on the first type optical disk 101. Writing and reading of an information signal can be performed for the entire area.

If the control circuit determines that the second type of optical disk 102 is mounted on the disk table, the control circuit switches the semiconductor laser chip of the laser coupler 33 or the second semiconductor laser 38a. Light is emitted and the first semiconductor laser 38 is extinguished. At this time, the second laser beam that has passed through the second objective lens 5 is irradiated onto the second type optical disc 102 from the transparent substrate side of the second type optical disc 102, passes through the transparent substrate, and
The light is focused on the signal recording layer. The second objective lens 5 is moved and operated by the second biaxial actuator 3 in the optical axis direction of the second objective lens 5 and in a direction orthogonal to the optical axis. The second objective lens 5 is moved and operated by the second biaxial actuator 3 following the displacement (so-called surface deflection) of the second type of optical disc 102 in the optical axis direction of the second objective lens 5. As a result, the focal point of the laser beam is always positioned on the signal recording layer. Also, this second
Is moved by the second biaxial actuator 3 to follow the displacement of the recording track of the second type optical disc 102 in the direction orthogonal to the optical axis of the second objective lens 5. As a result, the focal point of the second laser beam is always positioned on the recording track.

This optical pickup writes and reads information signals to and from this signal recording layer by condensing and irradiating the second laser beam onto the signal recording layer of the second type optical disc 102. In writing the information signal, if the second type optical disk 102 is a magneto-optical disk, the magneto-optical disk is irradiated with the second laser beam and the irradiation position of the second laser beam. Is applied with an external magnetic field. By modulating either the optical output of the second laser beam or the intensity of the external magnetic field according to the information signal to be recorded, the information signal is written to the magneto-optical disk. When the second type optical disk 102 is a phase change type disk, the optical output of the second laser beam is modulated according to the information signal to be recorded, thereby writing the information signal to the phase change type disk. Is performed.

In this optical pickup, the second type optical disc 102 has the second type on the signal recording layer.
The laser beam is condensed and irradiated, and the reflected light beam of the laser beam by the signal recording layer is detected, so that an information signal is read from the signal recording layer.

In reading the information signal, when the second type optical disk 102 is a magneto-optical disk, the change in the polarization direction of the reflected light beam is detected to detect
An information signal is read from the magneto-optical disk.
When the second type optical disk 102 is a phase change type disk or a so-called pit disk,
By detecting a change in the amount of reflected light of the reflected light flux, an information signal is read from the phase change type disk.

That is, the second light focused on the signal recording layer
Is reflected by the signal recording layer and returns to the second objective lens 5 as a reflected light beam. The reflected light flux returning to the second objective lens 5 is
And a second reflecting mirror 34, a laser coupler 33,
Alternatively, the process returns to the second beam splitter 28a. The laser coupler 33 or the second beam splitter 28
The reflected light flux returned to the second beam splitter 28a or the second beam splitter 28a
, And is branched to the optical path returning to the second semiconductor laser 38a, and travels toward the first or second photodetector 32a of the laser coupler 33.

The reflected light flux returning to the beam splitter surface of the laser coupler 33 is transmitted through the beam splitter surface and enters the beam splitter prism, whereby it is branched from the optical path returning to the semiconductor laser chip, and is subjected to the first light detection. Is received by the detector. The reflected light beam is reflected by the surface of the first photodetector and the inner surface of the beam splitter prism, and is also received by the second photodetector.
Based on the photodetection output output from each photodetector, a second
A read signal of an information signal recorded on the optical disk 102 of the type, a so-called RF signal, a shift in the optical axis direction between the focal point of the second laser beam by the second objective lens 5 and the surface of the signal recording layer, that is, A focus error signal indicating a focus error, and a shift of the focus point and a recording track formed on the surface of the signal recording layer in a direction perpendicular to the optical axis and the recording track, that is, a tracking error. The tracking error signal shown is calculated.

That is, the read signal is obtained as the sum of the respective photodetection outputs of the respective photodetectors. Further, the focus error signal is obtained as a difference between each light detection output of each light detector. Further, the tracking error signal is a sum of the light detection output from the light receiving surface on one side of the first photodetector and the light detection output from the light receiving surface on the other side of the second photodetector. 1
And the sum of the light detection output from the light receiving surface on one side of the second photodetector and the light detection output from the light receiving surface on the other side of the second photodetector.

Further, the second beam splitter 28a
Since the plane parallel plate is inclined at an angle of 45 ° with respect to the optical axis of the reflected light beam, astigmatism is generated in the reflected light beam. By detecting the direction and amount of the astigmatism, a focus error signal is generated. The focus error signal is generated between the focal point of the second laser beam by the second objective lens 5 and the surface of the signal recording layer of the second type optical disc 102 in the optical axis direction of the second objective lens 5. This is a signal indicating the amount and direction of the positional shift. Further, a tracking error signal is generated based on the detection output of the second photodetector 32a. The tracking error signal is a position between the focal point of the second laser beam by the second objective lens 5 and the recording track of the second type optical disc 102 in the direction orthogonal to the optical axis of the second objective lens 5. It is a signal indicating the amount and direction of the displacement.

The second biaxial actuator 3 is driven based on the focus error signal and the tracking error signal.

The optical pickup is moved along the guide shaft 18 and the support shaft 19 so that the second objective lens 5 faces the entire area of the signal recording area of the second type optical disc 102. By performing the moving operation, the information signal can be written and read for the entire signal recording area. That is, the optical pickup is moved over the inner and outer peripheries of the second type optical disc 102, and the second type optical disc 102 is rotated to thereby perform signal recording on the second type optical disc 102. Writing and reading of an information signal can be performed for the entire area.

Then, in the disk player, the optical disks 101, 1 mounted on the disk table 40 are read.
02, the thickness of the optical disc 101,
The determination can be made by the control circuit based on the amplitude of the RF signal read from 102. That is, when one of the first and second types of optical discs 101 and 102 is mounted on the disc table, the semiconductor laser chip of the laser coupler 33 or the first and second semiconductor lasers 38 and 38a are used. One of the predetermined lights is emitted. At this time, if only the focus servo is operated, the amplitude of the RF signal can be detected and the semiconductor laser chip of the laser coupler 33 or the first and second semiconductor lasers 3 emit light.
8 and 38a, and which of the first and second types of optical discs 101 and 102 is mounted on the disc table based on the amplitude of the detected RF signal. You can determine if there is.

[0117] In the optical pickup shown in FIG. 1, the tracking direction in the second biaxial actuator 3 shown in Fig. 1 arrow T ₂ are, as shown by arrow in FIG theta, and normal line of the recording track ₁ is tilted with respect to the tracking direction in the first biaxial actuator 2 indicated by an arrow T1 in FIG.

[6] Another Example of a Plurality of Optical Paths In this optical pickup, as shown in FIG. 9, the first and second luminous fluxes in the frame 1 are reflected by a reflection mirror in one of these optical paths. It may not be provided. That is, the first laser beam emitted from the first semiconductor laser is incident on the flat beam splitter 28. The beam splitter 28 is disposed such that its main surface is at an angle of 45 ° with respect to the optical axis of the first laser beam. This beam splitter 28 transmits a part of the first laser beam and reflects the rest. The first laser beam reflected by the beam splitter 28 is reflected by the reflection mirror 30 and
Is injected to the outside of the frame 1 through a through hole provided in the upper surface of the frame 1. Then, the first laser beam is incident on the first objective lens 4. The first objective lens 4 transmits the first laser beam to the first type optical disc 10.
The light is focused on the first signal recording layer.

Then, the second laser beam emitted from the second semiconductor laser 38a in the frame 1 is incident on the flat beam splitter 28a. The beam splitter 28a is disposed such that its main surface is at an angle of 45 ° with respect to the optical axis of the second laser beam. The beam splitter 28a transmits a part of the second laser beam and reflects the rest. This beam splitter 28a
The second laser beam reflected by the laser beam is emitted to the outside of the frame 1 through a through hole provided in the upper surface of the frame 1. Then, the second laser beam is incident on the second objective lens 5. This second objective lens 5
Converts the second laser beam into a second type optical disc 102
Is focused on the signal recording layer.

Here, the first semiconductor laser 38
The first optical path leading to the objective lens 4 and the second optical path leading from the second semiconductor laser 38a to the second objective lens 5 have their optical axes crossed at an intersection X. This intersection X is located between the beam splitter 28 and the reflection mirror 30 on the first optical path. The intersection X is located between the beam splitter 28a and the second objective lens 5 on the second optical path.

Also in this optical pickup, since the optical paths intersect each other, the sum of the volumes occupied by these optical paths is reduced by the overlap of the optical paths. Therefore, also in this optical pickup, the size of the frame 1 can be reduced.

Further, the optical pickup according to the present invention includes three or more light sources and three or more objective lenses corresponding to these light sources, and the plurality of light sources are used to convert the plurality of objective lenses to a plurality of objective lenses. It may be configured as forming a plurality of three or more optical paths. Also in this case, the optical paths cross each other, so that the frame can be downsized. As described above, when three or more optical paths are formed, a deflecting optical element such as a reflection mirror is disposed on all the optical paths corresponding to each optical path, or one optical path is provided. It is arranged on all the other optical paths except for the other optical paths.

Further, in the optical pickup according to the present invention, the biaxial actuator may be one in which a plurality of objective lenses are mounted on the same movable part.

[0124]

As described above, in the optical pickup according to the present invention, a plurality of light beams from a plurality of light sources to a plurality of objective lenses disposed corresponding to the plurality of light sources cross each other. ing. Therefore, in this optical pickup, the sum of the volumes occupied by the light beams is reduced by the overlapping of the light beams.

That is, the present invention relates to an optical pickup having a plurality of light sources and a plurality of objective lenses so that an information signal can be written and read to and from an optical recording medium having a transparent substrate having a different thickness. The configuration can be reduced in size.

Further, the present invention can provide a disk player having a compact device configuration by including the optical pickup according to the present invention.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of an optical pickup according to the present invention.

FIG. 2 is a plan view showing a configuration of the optical pickup in the disc player according to the present invention.

FIG. 3 is a longitudinal sectional view showing a configuration of the optical pickup.

FIG. 4 is an exploded perspective view showing a configuration of the optical pickup.

FIG. 5 is a perspective view showing a configuration of an optical system of the optical pickup.

FIG. 6 is an exploded perspective view showing a configuration of a biaxial actuator of the optical pickup.

FIG. 7 is a plan view showing another example of the configuration of the optical pickup according to the present invention in the disc player according to the present invention.

FIG. 8 is a side view showing the configuration of the optical pickup shown in FIG.

FIG. 9 is a side view showing still another example of the configuration of the optical pickup according to the present invention.

FIG. 10 is a plan view showing a configuration of a conventional optical pickup having one objective lens.

11 is a side view showing the configuration of the conventional optical pickup shown in FIG.

FIG. 12 is a plan view showing a configuration of a conventional optical pickup having two objective lenses.

[Explanation of symbols]

2 First biaxial actuator, 3 Second biaxial actuator, 4 First objective lens, 5 Second objective lens, 30 First reflection mirror, 34 Second reflection mirror, 38 First semiconductor laser , 38a second semiconductor laser, 101 first type optical disk, 102 second type optical disk, X optical path intersection

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuya Okushita 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Masami Miike 6-7-1, Kita-Shinagawa, Shinagawa-ku, Tokyo No. 35 Sony Corporation

Claims (8)

[Claims] A plurality of light sources; a plurality of objective lenses disposed so as to have optical axes parallel to each other corresponding to the plurality of light sources, and receiving a light beam emitted from each of the corresponding light sources; One or a plurality of deflecting optical elements disposed on an optical path excluding at most one of a plurality of optical paths from the light source to each of the objective lenses, One or a plurality of biaxial actuators movably supported in a direction parallel to the optical axis of the objective lens and a direction perpendicular to the optical axis, and the plurality of biaxial actuators, wherein the plurality of optical paths cross each other. Optical pickup featured. 2. The optical pickup according to claim 1, wherein the plurality of objective lenses have different numerical apertures. 3. The optical pickup according to claim 1, wherein the plurality of light sources emit light beams having wavelengths different from each other. 4. The optical pickup according to claim 1, wherein the plurality of optical paths intersect with each other at a portion formed in a direction perpendicular to the optical axis of each objective lens. 5. A rotation operation mechanism for supporting and rotating an optical disk, a plurality of light sources, and a plurality of light sources. The light sources are arranged so that their optical axes are parallel to each other. A plurality of objective lenses for receiving a light beam and condensing the light beam on a signal recording surface of an optical disk supported by the rotation operation mechanism; and at least one of a plurality of optical paths from the light sources to the objective lenses, respectively. And one or a plurality of deflecting optical elements deflecting the optical path and supporting each of the objective lenses in a direction parallel to the optical axis of the objective lens and by the rotation operation mechanism. One or more biaxial actuators that are movably supported in the radial direction of the selected optical disc, and the type of the optical disc supported by the rotary operation mechanism is detected and detected. And control means for selectively lighting one of the plurality of light sources in accordance with the type, the plurality of optical paths, disc player, characterized by being crossed with each other. 6. The disc player according to claim 5, wherein the plurality of objective lenses have different numerical apertures. 7. The disk player according to claim 5, wherein the plurality of light sources emit light beams having different wavelengths. 8. The disc player according to claim 5, wherein the plurality of optical paths intersect each other at a portion that is perpendicular to the optical axis of each objective lens.