JPH11176012A - Optical pickup and optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup and an optical disk device of which parts constitution is made simple, which can be easily assembled and of which optical parts can be precisely mounted. SOLUTION: The pickup includes a light receiving and emitting element 21, a light dividing means 22b which divides the light beams emitted from the light source section of the element 21, optical path bending means 22a and 22e which bend the optical paths of the light beams from the means 22b, an optical converging means 23, in which the light beams reflected by optical path bending means 22a and 22e are focused and illuminated on the signal recorded surface of an optical disk 11 that is rotatively driven, and an optical branching means 22c which branches the returning light beams from the signal recorded surface of the disk 11. Moreover, the returning light beams from the signal recorded surface of the disk 11 are branched by the means 22c and made incident on the light receiving section of the element 21 and the means 22c is integrally constituted with the means 22a and 22c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup and an optical disk device for irradiating a surface of a rotating optical disk with light and detecting return light.

[0002]

2. Description of the Related Art Conventionally, an optical pickup for reproducing an optical disk, for example, a compact disk (CD), has
For example, it is configured as shown in FIG.

In FIG. 7, an optical pickup 1 includes, for example, a light receiving / emitting element 2, a coupling lens 3, a rising mirror 4, and an objective lens 5. The light-receiving / emitting element 2 has a known configuration, and is formed by encapsulating a light-emitting element and a light-receiving element in a semiconductor package as an integrated optical block, and is configured, for example, as shown in FIG. The coupling lens 3 is a convex lens in the illustrated case, and is used for appropriately adjusting the length of an optical path by the objective lens 5 described later.

The rising mirror 4 is disposed at an angle of 45 degrees with respect to the optical path from the light emitting / receiving element 2 and bends a light beam emitted from the light emitting / receiving element 2 in a horizontal direction substantially at a right angle.
This is to make the light enter the surface of the optical disk D perpendicularly. The objective lens 5 is a convex lens, and rotates the optical beam from the light emitting / receiving element 2 to an optical disc D
Is formed on a desired track of the signal recording surface. Further, the objective lens 5 is supported by a biaxial actuator (not shown) so as to be movable in a biaxial direction, that is, a focusing direction and a tracking direction.

In FIG. 8, a light emitting / receiving element 2 has a second semiconductor substrate 2b mounted on a first semiconductor substrate 2a, and a laser diode chip 2c mounted on the second semiconductor substrate 2b.

The laser diode chip 2c is provided on the first semiconductor substrate 2a in front of the laser diode chip 2c.
A trapezoidal prism 2d having an inclined surface (light path branch surface) on its side is provided, and a semi-transmissive film (not shown) as a beam splitter is formed on the light path branch surface 2e. The prism 2d has a total reflection film (not shown) formed on its upper surface, and a semi-transmissive film (not shown) formed on its lower surface. The prism 2d reflects the light beam emitted from the laser diode chip 2c upward by the optical path branch surface, and emits the light beam to the outside. The light beam emitted from the light receiving / emitting element 2 is
As shown in FIG. 7, the light enters the objective lens 5 via the coupling lens 3 and the rising mirror 4, and is focused and focused on the signal recording surface of the optical disk D (for example, CD) by the objective lens 5. The return light beam reflected by the optical disk D enters the prism 2d of the light emitting / receiving element 2 via the objective lens 5, the rising mirror 4, and the coupling lens 3, and is sequentially reflected on the bottom and top surfaces of the prism 2d. As a result, the light is emitted below the prism 2d at two places on the bottom surface of the prism 2d.

On the top surface of the first semiconductor substrate 2a, photodetectors 2f and 2g are formed at positions where light emitted from two places on the bottom surface of the prism 2d is received. Each of the photodetectors 2f and 2g includes a light receiving unit appropriately divided for the return light beam, detects an information signal read by the optical disc D, and based on a detection signal from each light receiving unit. The focus error signal FE and the tracking error signal TE are detected.

[0008]

In the above-described optical pickup 1, since the pit depth of the CD is generally set to about λ / 5, the push-pull signal can be detected without any problem. Therefore, the tracking error signal TE is detected by a so-called push-pull method.

On the other hand, for example, in the case of a high-density optical disk, since the pit depth is about λ / 4, the push-pull signal disappears,
The tracking error signal TE is generally detected by a so-called three-beam method by detecting a side beam split by a grating. In this case, a grating is required and
The optical pickup 1 is configured so that the return light beam of the side beam split by the grating does not enter the grating again, and optical means for that purpose is further required.

However, according to the optical pickup having such a configuration, each optical component, ie, the light receiving / emitting element 2, the coupling lens 3, the rising mirror 4, the objective lens,
In some cases, the grating and the like are manufactured as separate components, and are assembled while performing optical adjustment. For this reason, the number of parts increases and the parts cost increases, and at the time of assembling, it is necessary to assemble each optical part with high precision, which increases the assembling time and increases the assembling cost. There was a problem. Furthermore, there is a problem that it is difficult to improve the performance of the optical pickup because there is a limit in the mounting accuracy when assembling parts.

In view of the above, the present invention provides an optical pickup and an optical disk apparatus which can be easily assembled by adopting a simple component configuration, and in which each optical component can be attached with high precision. It is intended to be.

[0012]

According to the present invention, there is provided a light receiving / emitting element, a light splitting means for splitting a light beam emitted from a light source section of the light receiving / emitting element, and a light splitting means. Optical path bending means for bending the optical path of the light beam;
Light focusing means for irradiating the light beam reflected by the optical path bending means so as to be focused on the signal recording surface of the optical disk which is rotationally driven; and light for branching the return light beam from the signal recording surface of the optical disk A return light beam from the signal recording surface of the optical disc, after an optical path is branched by the light branching means, to be incident on a light receiving unit of a light receiving / emitting element at a position different from the light source unit. Further, the above-mentioned optical branching means is achieved by an optical pickup integrated with the optical path bending means.

According to the above arrangement, when reproducing an optical disk, the light beam emitted from the light source unit of the light receiving / emitting element is split into three beams by the light splitting means. The optical disc is focused on the signal recording surface of the optical disc, and the return light beam from the optical disc again enters the light receiving portion of the light receiving / emitting element via the light focusing means and the optical path bending means. Thus, the reproduction signal of the optical disk, the tracking error signal, and the focus error signal are detected based on the detection signal from the light receiving section.

In this case, the return light beam from the optical disk is directly incident on the light receiving portion of the light receiving / emitting element without passing through the light splitting means by branching the optical path by a light branching means such as a hologram element. Therefore, the tracking error signal is detected by a so-called three-beam method. As a result, as compared with the push-pull method, the offset is less affected by the pit depth of the optical disk, is more resistant to lens shift and disk skew, and is less likely to cause offset. This eliminates the need for an offset cancellation circuit, and performs accurate tracking servo.

Further, since the light branching means is formed integrally with the light path bending means, mutual positioning of the light branching means and the light path bending means becomes unnecessary, and the number of parts is reduced. . Therefore, with a simple structure, various optical disks can be accurately reproduced, the number of components is reduced, the assembly is performed easily and with high accuracy, and the cost is reduced.

Further, an optical element for adjusting the optical path length from the light receiving / emitting element to the objective lens is provided. When this optical element is integrally formed with the prism mirror, the number of parts is further reduced. Is done.

If the light splitting means is formed integrally with the prism mirror on the exit surface of the prism mirror where the return light exits, the number of components is further reduced.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. still,
Since the embodiments described below are preferred specific examples of the present invention, various technically preferred limitations are added.
The scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

FIG. 1 shows the configuration of an optical disk device incorporating an optical pickup according to an embodiment of the present invention. In FIG. 1, an optical disk device 10 includes a spindle motor 12 as a driving unit that rotationally drives an optical disk 11, and an optical pickup 13. here,
The spindle motor 12 is driven and controlled by an optical disk drive controller 14 and is rotated at a predetermined rotation speed. The optical disc 11 can select and reproduce a plurality of types of optical discs.

The optical pickup 13 irradiates the signal recording surface of the rotating optical disk 11 with light to record a signal or to detect return light from the signal recording surface. A reproduced signal based on the return light is output to the signal demodulator 15.

As a result, the recording signal demodulated by the signal demodulator 15 is corrected for error through an error correction circuit 16 and sent to an external computer or the like via an interface 17. With this, the external computer etc.
A signal recorded on the optical disk 11 can be received as a reproduction signal.

The optical pickup 13 is connected to a head access control unit 18 for moving the optical pickup 13 to a predetermined recording track on the optical disk 11 by a track jump or the like. Further, a servo circuit 19 for moving the objective lens in the focusing direction and the tracking direction is connected to the biaxial actuator holding the objective lens of the optical pickup 13 at the moved predetermined position.

FIG. 2 shows a first embodiment of the optical pickup according to the present invention. In FIG. 2, an optical pickup 13 includes a light emitting / receiving element 21 and a light emitting / receiving element 21,
The optical system includes a multifunction optical element 22 disposed in an optical path 22 and an objective lens 23 as light focusing means.

The light emitting / receiving element 21 is, as described later,
A semiconductor laser element as a light source section and a photodetector as a light receiving section are integrally formed, and are arranged so as to be shifted in a direction perpendicular to the optical axis.

In the case of the figure, the composite function optical element 22 is basically composed of a prism 22a, and a grating 22b as a light splitting means and a hologram element 2 as a light splitting means are provided on the prism 22a.
2c and a coupling lens 22d are integrally formed and an inclined surface 22e acting as an optical path bending means.
It has.

Here, the prism 22a is basically a right-angle prism, and has an inclined surface 22e which functions as an optical path bending mirror disposed at an angle of 45 degrees with respect to the optical path of the light receiving / emitting element 21. ing. The prism 22a further includes a grating 22b in the optical path on the side of the light emitting / receiving element 21 from the inclined surface 22e.
The hologram element 22c and the coupling lens 22d are provided on the end face on one side.

The grating 22b is a diffraction grating, and divides the incident light beam into a main beam as a zero-order light and a side beam as a plus or minus primary light.

The hologram element 22c is formed as a diffraction grating type element with a hologram surface having a grating formed on the incident side of the substrate. Thereby, the hologram element 22c converts the light beam from the light receiving / emitting element 21 into
As shown in FIG. 3A, the light beam is transmitted as it is, and the return light beam from the optical disk 11 is diffracted as shown in FIG. 3B.

The coupling lens 22d is a convex lens in the case shown, and is used for adjusting the focal length of the objective lens 23 described later.

The objective lens 23 is a convex lens, and forms an image of a light beam reflected by the inclined surface 22e of the multifunctional optical element 22 on a desired track of a signal recording surface of the optical disk 11 which is driven to rotate. . Further, the objective lens 23 is supported by a biaxial actuator (not shown) so as to be movable in biaxial directions, that is, in a tracking direction and a focusing direction.

Here, the light emitting / receiving element 21 will be described in detail. As shown in FIG. 2, the light emitting / receiving element 21 has a semiconductor laser diode chip 21b as a light source unit mounted on a semiconductor substrate 21a and a semiconductor substrate 2 adjacent to the semiconductor laser diode chip 21b.
On 1a, a photodetector 21c as a light receiving unit is formed. As is well known, the photodetector 21c is divided so as to have a light receiving portion for each of the main beam and the two side beams divided into three by the grating 22b, and each light receiving portion is read by an optical disk. The information signal is detected, and the reproduction signal RF, the focus error signal FE, and the tracking error signal TE are obtained based on the detection signal from each light receiving unit.

The optical pickup 13 according to the present embodiment
Is configured as described above, and a case where the optical disk 11 is reproduced will be described.

The light beam from the semiconductor laser diode chip 21b of the light emitting / receiving element 21 first enters the prism 22a of the multifunction optical element 22, and the grating 23
After being divided into a main beam and two side beams, the light is reflected by the inclined surface 22e, exits from the prism 22a, further passes through the hologram element 22c, the coupling lens 22d, and passes through the objective lens 23. It is focused on the signal recording surface of the optical disc 11. At this time, the light beam from the light receiving / emitting element 21 is transmitted to the hologram element 22c.
Is transmitted as it is. The return light from the optical disk 11 is
The light again enters the hologram element 22c via the objective lens 23 and the coupling lens 22d, and is diffracted by the hologram element 22c. As a result, the return light beam deviates from the optical path from the semiconductor laser diode chip 21b of the light receiving / emitting element 21 due to diffraction by the hologram element 22c. Therefore, the return light beam enters the prism 22a, is reflected by the inclined surface 22e, and then directly enters the photodetector 21c of the light emitting / receiving element 21 without passing through the grating 22b. Thereby, based on the detection signal from the photodetector 21c, the reproduction signal RF, the focus error signal FE, and the tracking error signal TE relating to the optical disk 11 are detected, and the recording signal of the optical disk 11 is reproduced.

In this case, the multifunctional optical element 22 described above is used.
Is a prism 22b having a grating 22b as a light splitting means and an inclined surface 22e as an optical path bending means.
a, since the hologram element 22c and the coupling lens 22d as light splitting means are integrally formed with each other, alignment between these optical elements can be performed with high accuracy, and optical position adjustment is not required. Become. Accordingly, the number of parts of the optical pickup 13 is greatly reduced, and the assembling is easily performed, so that the parts cost and the assembling cost are reduced.

FIG. 4 shows a second embodiment of the optical pickup according to the present invention. In FIG. 4, the optical pickup 30 has substantially the same configuration as the optical pickup 13 shown in FIG. 2, but differs in that the coupling lens 22d is omitted. In the drawings, the portions denoted by the same reference numerals as those used in the description of the first embodiment have the same configuration, and thus the duplicate description will be omitted, and the description will focus on the differences.

According to the optical pickup 30 having such a configuration, as compared with the optical pickup 13 shown in FIG. 2, only the correction of the optical path length by the coupling lens 22d is not performed, but other functions are the same. is there. That is, when reproducing the optical disk 11, the light beam from the semiconductor laser diode chip 21b of the light emitting / receiving element 21 first enters the prism 22a of the multifunction optical element 22,
After being divided into a main beam and two side beams by the grating 23, the beam is reflected by the inclined surface 22e, exits from the prism 22a, further passes through the hologram element 22c, passes through the objective lens 23, and passes through the objective lens 23. It is focused on the signal recording surface. At this time, the light beam from the light emitting / receiving element 21 passes through the hologram element 22c as it is.

The return light from the optical disk 11 again enters the hologram element 22c via the objective lens 23,
The light is diffracted by the hologram element 22c. As a result, the return light beam deviates from the optical path from the semiconductor laser diode chip 21b of the light receiving / emitting element 21 due to diffraction by the hologram element 22c. Therefore, the return light beam enters the prism 22a, is reflected by the inclined surface 22e, and then directly enters the photodetector 21c of the light emitting / receiving element 21 without passing through the grating 22b. Thereby, based on the detection signal from the photodetector 21c, the reproduction signal RF, the focus error signal FE, and the tracking error signal TE relating to the optical disk 11 are detected, and the recording signal of the optical disk 11 is reproduced.

Also in this case, similarly, the above-mentioned multifunctional optical element 22 is provided with a grating 2 as a light splitting means.
2b, a prism 22a having an inclined surface 22e as an optical path bending unit, and a hologram element 2 as an optical branching unit
2c are integrally formed with each other, so that alignment between these optical elements can be performed with high accuracy, and
No optical position adjustment is required. Therefore, the number of parts of the optical pickup 30 is significantly reduced, and the assembling is easily performed, so that the parts cost and the assembling cost are reduced.

FIG. 5 shows a third embodiment of the optical pickup according to the present invention. 5, the optical pickup 40 has substantially the same configuration as the optical pickup 13 of FIG. 2, but includes a hologram element 41 attached to the inclined surface 22e of the prism 22a instead of the hologram element 22c. Has a different configuration. In the drawings, the portions denoted by the same reference numerals as those used in the description of the first embodiment have the same configuration, and thus the duplicate description will be omitted, and the description will focus on the differences. In this case, the hologram element 41 is configured to reflect the light beam from the light emitting / receiving element 21 as it is and to reflect the return light beam from the optical disc 11 while diffracting the light beam.

According to the optical pickup 40 having such a configuration, when reproducing the optical disk 11, the light beam from the semiconductor laser diode chip 21 b of the light emitting / receiving element 21 firstly receives the prism 22 a of the multifunction optical element 22.
And is divided into three parts by a grating 23 into a main beam and two side beams.
The light is reflected by the hologram element 41 provided in the lens and emitted from the prism 22a.
Through the objective lens 23 and the optical disk 11
Is focused on the signal recording surface. At this time, the light emitting / receiving element 21
Is reflected by the hologram element 22c as it is.

The return light from the optical disk 11 again enters the prism 22a via the objective lens 23 and the coupling lens 22d, and enters the hologram element 22c provided on the inclined surface 22e.
The light is reflected while being diffracted by 2c. This allows
The return light beam deviates from the optical path from the semiconductor laser diode chip 21b of the light receiving / emitting element 21 due to diffraction by the hologram element 22c. Therefore, the return light beam directly enters the photodetector 21c of the light emitting / receiving element 21 without passing through the grating 22b. Thereby, based on the detection signal from the photodetector 21c, the reproduction signal RF, the focus error signal FE, and the tracking error signal TE relating to the optical disk 11 are detected, and the recording signal of the optical disk 11 is reproduced.

In this case, the multifunctional optical element 22 described above is used.
Is a prism 22b having a grating 22b as a light splitting means and an inclined surface 22e as an optical path bending means.
a, the coupling lens 22d and the hologram element 41 as a light splitting means are integrally formed with each other, so that the alignment between these optical elements can be performed with high accuracy, and the optical position adjustment is not required. Become. Therefore, the number of components of the optical pickup 40 is greatly reduced, and the assembling is facilitated, so that the component cost and the assembly cost are reduced.

FIG. 6 shows a fourth embodiment of the optical pickup according to the present invention. 6, the optical pickup 50 has substantially the same configuration as the optical pickup 40 shown in FIG. 5, but differs in that the coupling lens 22d is omitted. In the drawings, the portions denoted by the same reference numerals as those used in the description of the first embodiment have the same configuration, and thus the duplicate description will be omitted, and the description will focus on the differences.

According to the optical pickup 50 having such a configuration, as compared with the optical pickup 13 shown in FIG. 5, only the correction of the optical path length by the coupling lens 22d is not performed, and other functions are the same. is there. That is, when the optical disk 11 is reproduced or when the optical disk 11 is reproduced, the light beam from the semiconductor laser diode chip 21b of the light emitting / receiving element 21 first enters the prism 22a of the multifunction optical element 22, and 2
3 is divided into a main beam and two side beams by three, and then the hologram element 4 provided on the inclined surface 22e
The light is reflected by 1 and exits from the prism 22a, and is focused on the signal recording surface of the optical disk 11 via the objective lens 23. At this time, the light beam from the light emitting / receiving element 21 is reflected by the hologram element 22c as it is.

The return light from the optical disk 11 again enters the prism 22a via the objective lens 23, enters the hologram element 22c provided on the inclined surface 22e, and is reflected while being diffracted by the hologram element 22c. Is done. As a result, the return light beam deviates from the optical path from the semiconductor laser diode chip 21b of the light receiving / emitting element 21 due to diffraction by the hologram element 22c. Therefore, the return light beam directly enters the photodetector 21c of the light emitting / receiving element 21 without passing through the grating 22b. Thereby, the photodetector 2
Based on the detection signal from 1c, the reproduction signal RF, focus error signal FE, and tracking error signal TE relating to the optical disk 11 are detected, and the recording signal of the optical disk 11 is reproduced.

In this case, similarly, the above-mentioned multifunctional optical element 22 is provided with a grating 2 as a light splitting means.
2b, a prism 22a having an inclined surface 22e as an optical path bending unit, and a hologram element 4 as an optical branching unit
Since the optical elements 1 are integrally formed with each other, alignment between these optical elements is performed with high accuracy, and optical position adjustment is not required. Therefore, the number of parts of the optical pickup 50 is greatly reduced, and the assembling is easily performed, so that the parts cost and the assembling cost are reduced.

In the above embodiment, the multifunctional optical element 22 includes the grating 22b and the hologram element 22.
Although c or 41 and the coupling lens 22d are integrally formed, it is apparent that at least two of these optical elements may be integrally formed.
In this case, with respect to the optical elements formed integrally, mutual alignment is performed with high accuracy, and optical adjustment at the time of assembling is not required, so that component costs and assembly costs are reduced. .

[0048]

As described above, according to the present invention, it is possible to easily assemble by using a simple component structure and to mount each optical component with high accuracy.
An optical pickup and an optical disk device can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an optical disk device incorporating an optical pickup according to the present invention.

FIG. 2 is a schematic side view showing a configuration of a first embodiment of an optical pickup in the optical disk device of FIG. 1;

FIG. 3 is a schematic diagram showing an operation of a hologram element in the optical pickup of FIG.

FIG. 4 is a schematic side view showing a second embodiment of the optical pickup according to the present invention.

FIG. 5 is a schematic side view showing a third embodiment of the optical pickup according to the present invention.

FIG. 6 is a schematic side view showing a third embodiment of the optical pickup according to the present invention.

FIG. 7 is a schematic side view showing an example of a conventional optical pickup.

8 is a schematic sectional view of a light receiving / emitting element in the optical pickup of FIG. 7;

[Explanation of symbols]

10 optical disk device, 11 optical disk, 1
2 ... Spindle motor, 13 ... Optical pickup, 14 ... Optical disk drive controller, 15
... Signal demodulator, 16 ... Error correction circuit, 17 ...
Interface, 18 Head access control unit, 19 Servo circuit, 21 Light emitting / receiving element, 2
2 ... multifunctional optical element, 22a ... prism, 2
2b: grating, 22c: hologram element, 22d: coupling lens, 22e: inclined surface, 23: objective lens, 30, 40, 50 ...
Optical pickup, 41 ... hologram element.

Claims (8)

[Claims] A light receiving / emitting element; a light splitting means for splitting a light beam emitted from a light source unit of the light receiving / emitting element; an optical path bending means for bending an optical path of the light beam from the light splitting means; Light converging means for irradiating the light beam reflected by the optical path bending means so as to be focused on a signal recording surface of a rotationally driven optical disk; and light for branching a return light beam from the signal recording surface of the optical disk. A return light beam from the signal recording surface of the optical disc, after an optical path is branched by the light branching means, to be incident on a light receiving unit of a light receiving / emitting element at a position different from the light source unit. An optical pickup characterized in that the optical branching means is formed integrally with the optical path bending means. 2. The optical pickup according to claim 1, wherein said optical path bending means is a prism mirror. 3. The optical pickup according to claim 1, wherein said light splitting means is a hologram element. 4. The optical pickup according to claim 2, wherein the light splitting means is formed integrally with the prism mirror at an incident surface or a reflection surface of the return light of the prism mirror. 5. An apparatus according to claim 1, further comprising an optical element for adjusting an optical path length from the light receiving / emitting element to the objective lens, wherein the optical element is integrated with the prism mirror. 5. The optical pickup according to 4. 6. The optical element is formed integrally with the prism mirror on the incident surface of the return light of the prism mirror, and the light splitting means is formed integrally on the reflection surface of the return light of the prism mirror. The optical pickup according to claim 5, wherein: 7. The optical pickup according to claim 2, wherein the light splitting means is formed integrally with the prism mirror on the return light emitting surface side of the prism mirror. 8. A driving means for driving the optical disc to rotate, and a light irradiating the rotating optical disc through a light focusing means, and detecting a return light from a signal recording surface from the optical disc through the light focusing means. An optical pickup, a biaxial actuator that supports the light focusing means so as to be movable in two axial directions, a signal processing circuit that generates a reproduction signal based on a detection signal from the optical pickup, and a detection signal from the optical pickup. A servo circuit for moving the light focusing means in two axial directions, wherein the optical pickup comprises: a light receiving and emitting element; and a light dividing means for dividing a light beam emitted from a light source unit of the light receiving and emitting element. An optical path bending means for bending an optical path of a light beam from the light splitting means, and an optical disk rotationally driven by the light beam reflected by the optical path bending means Light focusing means for irradiating the signal recording surface of the optical disk so as to be focused, and light branching means for branching the return light beam from the signal recording surface of the optical disk, and the return light from the signal recording surface of the optical disk. The beam is incident on a light receiving section of a light receiving / emitting element located at a position different from the light source section after the light path is branched by the light branching section. Further, the light branching section includes an optical path bending section. An optical disk device characterized by being integrally formed with the optical disk device.