JP2001110082A - Optical pickup and optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a stray light that is caused when the light transmitted through a light separating means is reflected on the light projection plane of the light separating means from being generated and to secure the stable operations of an optical pickup and an optical disk device. SOLUTION: A reflection preventing treatment is applied on a light projection plane of a light separating means where the light beam that is emitted from a light source and transmitted through the light separating means is projected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk such as a magneto-optical disk (hereinafter referred to as "optical disk").
1. Field of the Invention The present invention relates to an optical pickup for recording and / or reproducing a signal from and to an optical disc device provided with the optical pickup.

[0002]

2. Description of the Related Art Conventionally, as an optical pickup for a magneto-optical disk, for example, an optical pickup configured as shown in FIG. 10 has been put to practical use.

The optical pickup 1 shown in FIG.
For example, the optical pickup is configured as an optical pickup for a mini-disc (MD), and is an astigmatism correction plate sequentially disposed in an optical path of a light beam emitted from a semiconductor laser element 2 as a light source and traveling toward an optical disk D. 3a, the grating 3b, the beam splitter 4, the collimator lens 5, the rising mirror 6, the objective lens 7, and the woras sequentially arranged in the optical path of the return light from the optical disc D separated by the separation film 4a of the beam splitter 4. A ton prism 8a, a multi-lens 8b, and a photodetector 9 are provided, and these optical components are individually mounted.

In the optical pickup 1 having such a configuration, the light beam emitted from the semiconductor laser element 2 is corrected for astigmatism by the astigmatism correction plate 3a, and is then combined with the main beam by the grating 3b. The light beam is split into three light beams of one side beam, and each of the light beams enters the beam splitter 4.

A part of the light beam incident on the beam splitter 4 passes through the separation film 4 a of the beam splitter 4, is converted into parallel light by a collimator lens 5, and the light path is bent by a rising mirror 6. The light is converged by the objective lens 7 and irradiated onto the signal recording surface of the optical disc D. At this time, 3
Each of the divided light beams forms three spots on the signal recording surface of the optical disc D.

[0006] The light beam irradiated on the signal recording surface of the optical disc D is caused by the magnetic Kerr effect.
Of the magnetization of the portion of the signal recording surface irradiated with the light beam when reflected on the signal recording surface (recording state)
, The plane of polarization is rotated.

The return light beam reflected on the signal recording surface of the optical disk D is again supplied to the objective lens 7, the rising mirror 6,
The light enters the beam splitter 4 via the collimator lens 5.

A part of the return light beam incident on the beam splitter 4 is reflected by the separation film 4a of the beam splitter 4, and is incident on the Wollaston prism 8a.

The Wollaston prism 8a is a prism formed by laminating two uniaxial crystals, and refracts incident light due to the difference in the azimuth of the optical axes of the two uniaxial crystals at the junction surface of the two uniaxial crystals. The light is split into three light beams of p-polarized light, s-polarized light, and p + s-polarized light having different angles (polarization directions of the beam splitter 4 with respect to the separation film 4a). The return light that has entered the Wollaston prism 8a is divided into three by the Wollaston prism 8a, and is given astigmatism by the multi-lens 8b and the optical path length is extended. And signal detection is performed.

Here, of the return light received by the light receiving surface of the photodetector 9, a magneto-optical signal is detected based on the p-polarized light and the s-polarized light split by the Wollaston prism 8a. . That is, the polarization plane is rotated and reflected on the signal recording surface of the optical disk D, and the Wollaston prism 8 is rotated.
The return light separated into the p-polarized light and the s-polarized light by a is received by the light receiving surface of the photodetector 9, so that the magnetization state (recording state) of the signal recording surface of the optical disc D is changed to light. Will be detected as a change in intensity.

The return light received on the light receiving surface of the photodetector 9 is divided by the Wollaston prism 8a and p + is given astigmatism by the multi-lens 8b.
Based on the s-polarized light, a focus error signal is detected by a so-called astigmatism method. Further, based on two side beams split by the grating 3b, of the return light received by the light receiving surface of the photodetector 9,
A tracking error signal is detected by a so-called three spot method.

In the optical pickup 1, a light beam from the semiconductor laser element 2 forms a spot at a correct position on the signal recording surface of the optical disk D for accurate detection of a magneto-optical signal, thereby obtaining an accurate spot. The objective lens 7 is finely moved based on a predetermined servo signal so that a recorded signal is reproduced.

That is, the spot of the light beam is
A tracking servo for finely moving the objective lens 7 along the radial direction of the optical disk D so as to follow the recording track of the optical disk D is performed based on the tracking error signal, and a light beam is projected on the signal recording surface of the optical disk D. In order to properly form a spot, the objective lens 7
Is finely moved in the direction of moving toward and away from the signal recording surface of the optical disc D along the optical axis.
This is performed based on the focus error signal.

[0014]

By the way, in the optical pickup 1 having such a configuration, the recording information written on the optical disk D is read by a plurality of optical components individually mounted. In addition, it is difficult to reduce the size, the number of components is large, and the manufacturing process of each component, the assembling process of the optical pickup, and the optical adjustment process are complicated, and the cost is increased.

The present invention has been proposed in view of the above-mentioned conventional situation, and effectively realizes miniaturization of an optical pickup, enables reduction of manufacturing cost, and further improves reliability. It is an object of the present invention to provide an optical pickup to be operated and an optical disk device provided with the optical pickup.

[0016]

An optical pickup according to the present invention is an optical pickup for recording and / or reproducing signals by irradiating a signal recording surface of an optical disk with a light beam, comprising: an integrated optical element; Light focusing means for focusing the light beam and irradiating the signal recording surface of the optical disk with the light beam. The integrated optical element includes a light source that emits a light beam that irradiates a signal recording surface of the optical disk, a photodetector that receives a return light beam reflected by the signal recording surface of the optical disk, and one of the main detectors. Has an opening in the surface,
A package member for accommodating the light source and the photodetector therein, respectively, provided on a main surface having an opening of the package member, for transmitting a light beam emitted from the light source, and An optical member that transmits a return light beam toward the light source; and a light separating unit that is provided integrally with the optical member and separates a light beam emitted from the light source and a return light beam toward the photodetector. .

In the optical pickup according to the present invention, the optical member is provided on the optical path of a return light beam separated by the light separating means and traveling toward the photodetector to generate a focus error signal. Is formed integrally, and the light separating means is provided with an anti-reflection treatment on a light emitting surface from which a light beam emitted from the light source and transmitted through the light separating means is emitted. It is characterized by having.

In the optical pickup according to the present invention as described above, each optical element is integrated and integrated, and the focus error signal generating means is formed integrally with the light separating means. As a result, the number of parts can be reduced.

In this optical pickup,
Since the light source and the photodetector are integrally formed, for example, provided on one substrate, the number of lead wires for signal extraction can be reduced, the assembly work can be simplified, and the assembly cost can be reduced. In addition to this, mutual alignment between the light source and the photodetector becomes unnecessary.

Further, in this optical pickup, since the light exit surface of the light separating means is subjected to an antireflection treatment, generation of stray light is eliminated and stable operation can be ensured.

The optical pickup of the present invention is an optical pickup for irradiating a signal recording surface of an optical disk with a light beam to record and / or reproduce a signal.
An integrated optical element that emits a first light beam and a second light beam, and a light focusing unit that focuses the first light beam emitted from the integrated optical element and irradiates the first light beam onto a signal recording surface of the optical disk A first light beam receiving the second light beam emitted from the integrated optical element and controlling an output of a light beam emitted from a light source provided in the integrated optical element according to the power of the second light beam. And a photodetector.

The integrated optical element includes a light source for emitting a light beam for irradiating the signal recording surface of the optical disk, and a second light detecting device for receiving a return light beam reflected on the signal recording surface of the optical disk. And a package member that has an opening in one main surface portion and accommodates the light source and the second photodetector therein, respectively, and is provided on a main surface portion having an opening portion of the package member, An optical member for transmitting a light beam emitted from the light source and transmitting a return light beam toward the second photodetector; and a light beam provided integrally with the optical member and emitted from the light source. And a light separating means for separating the light beam into a first light beam and a second light beam, and separating the first light beam and the return light beam toward the second photodetector.

In the optical pickup of the present invention, the optical member is located on an optical path of a return light beam which is separated by the light separating means and travels toward the second photodetector. A focus error signal generating means for generating the light beam is integrally formed, and the light separating means is provided with an antireflection treatment on a light emitting surface from which the second light beam transmitted through the light separating means is emitted. It is characterized by having been done.

In the optical pickup according to the present invention as described above, each optical element is integrated and integrated, and the focus error signal generating means is formed integrally with the optical member, so that the overall size can be reduced. In addition, the number of parts can be reduced.

In this optical pickup,
Since the light source and the photodetector are integrally formed, for example, provided on one substrate, the number of lead wires for signal extraction can be reduced, the assembly work can be simplified, and the assembly cost can be reduced. In addition to this, mutual alignment between the light source and the photodetector becomes unnecessary.

Further, in this optical pickup, since the anti-reflection treatment is applied to the light exit surface of the light separating means, stray light does not occur and stable operation can be ensured.

Also, an optical disk device of the present invention irradiates a signal recording surface of an optical disk with a light beam and detects return light from the signal recording surface of the optical disk, and an optical detection device provided with the optical pickup. A signal processing circuit for generating a reproduction signal based on a detection signal from the optical disc, wherein the optical pickup comprises an integrated optical element, and a light converging means for converging the light beam and irradiating the light beam on a signal recording surface of the optical disc. And

The integrated optical element includes a light source for emitting a light beam for irradiating the signal recording surface of the optical disk, a photodetector for receiving a return light beam reflected on the signal recording surface of the optical disk, A package member that has an opening in one main surface portion and accommodates the light source and the photodetector therein, respectively, is provided on a main surface portion having an opening portion of the package member, and is emitted from the light source. An optical member that transmits a light beam and transmits a return light beam directed to the photodetector; and a light beam emitted from the light source and return light directed to the photodetector, which is provided integrally with the optical member. Light separating means for separating the light from the beam.

In the optical disc apparatus according to the present invention, the optical member is provided on the optical path of a return light beam separated by the light separating means and traveling toward the photodetector to generate a focus error signal. Is formed integrally, and the light separating means is provided with an anti-reflection treatment on a light emitting surface from which a light beam emitted from the light source and transmitted through the light separating means is emitted. It is characterized by having.

In the optical disk apparatus according to the present invention as described above, the optical elements of the integrated optical element are integrated and integrated, and the focus error signal generating means is formed integrally with the optical member. Thus, the size of the device can be reduced, and the number of components can be reduced.

Further, in this optical disk device, the light source and the photodetector of the integrated optical element are integrally formed, for example, provided on one substrate, so that the number of lead wires for signal extraction is reduced. In addition to reducing the number of light sources and simplifying the assembling work, the assembling cost is reduced, and the alignment between the light source and the photodetector is not required.

Further, in this optical disk device,
Since the light emission surface of the integrated optical element is subjected to the anti-reflection treatment, stray light is not generated, and stable operation can be ensured.

Also, an optical disk apparatus of the present invention irradiates a signal recording surface of an optical disk with a light beam and detects return light from the signal recording surface of the optical disk, and a first optical pickup provided in the optical pickup. Control means for controlling the output of the light beam emitted from the light source provided in the optical pickup based on the detection signal from the photodetector, and based on the detection signal from the second photodetector provided in the optical pickup. And a signal processing circuit for generating a reproduction signal. The optical pickup includes an integrated optical element for emitting a first light beam and a second light beam, and the first optical beam emitted from the integrated optical element.
A light converging means for converging the light beam and irradiating the signal recording surface of the optical disc with a second light beam emitted from the integrated optical element, and receiving the second light beam according to the power of the second light beam. A first light detector for controlling an output of a light beam emitted from a light source included in the integrated optical element.

The integrated optical element includes a light source for emitting a light beam for irradiating the signal recording surface of the optical disk, and a second light detecting device for receiving a return light beam reflected on the signal recording surface of the optical disk. And a package member that has an opening in one main surface portion and accommodates the light source and the second photodetector therein, respectively, and is provided on a main surface portion having an opening portion of the package member, An optical member for transmitting a light beam emitted from the light source and transmitting a return light beam toward the second photodetector; and a light beam provided integrally with the optical member and emitted from the light source. And a light separating means for separating the light beam into a first light beam and a second light beam, and separating the first light beam and the return light beam toward the second photodetector.

In the optical disc apparatus of the present invention, the optical member is located on an optical path of a return light beam which is separated by the light separating means and travels toward the second photodetector. A focus error signal generating means for generating the light beam is integrally formed, and the light separating means is provided with an antireflection treatment on a light emitting surface from which the second light beam transmitted through the light separating means is emitted. It is characterized by having been done.

In the above-described optical disk apparatus according to the present invention, in the above-described optical disk apparatus according to the present invention, each optical element of the integrated optical element is integrated and integrated, and a focus error signal generating means is provided. Are formed integrally with the optical member, so that the overall size can be reduced and the number of parts can be reduced.

Further, in this optical disk device, the light source and the photodetector of the integrated optical element are integrally formed and provided on, for example, one substrate, so that the number of lead wires for signal extraction is reduced. In addition to reducing the number of light sources and simplifying the assembling work, the assembling cost is reduced, and the alignment between the light source and the photodetector is not required.

Further, in this optical disk device,
Since the light emission surface of the integrated optical element is subjected to the anti-reflection treatment, stray light is not generated, and stable operation can be ensured.

[0039]

FIG. 1 shows an entire configuration of an example of an optical disk apparatus to which the present invention is applied. This optical disk device 1
Reference numeral 0 denotes a spindle motor 12 as a driving means for rotating and driving an optical disk such as a magneto-optical disk (hereinafter, referred to as an optical disk 11), and an optical disk 11 rotationally driven by the spindle motor 12, as shown in FIG.
An optical pickup 20 for irradiating a light beam to the signal recording surface of the optical disk 11, receiving a return light beam reflected by the signal recording surface of the optical disk 11, and reading a recording signal recorded on the signal recording surface of the optical disk 11, A control unit 13 for controlling the spindle motor 12 and the optical pickup 20 is provided.

The control unit 13 includes the optical disk controller 1
4, the signal processing circuit 15, and the APC (Auto-Power-Contr
ol) A circuit 16, an interface 17, a head access control unit 18, and a servo control unit 19 are provided.

The optical disk controller 14 controls the drive of the spindle motor 12 at a predetermined number of rotations.
The operation of each unit in the control unit 13 is controlled.

The signal processing circuit 15 includes the optical pickup 2
0 demodulates the recording signal read from the optical disk 11 and corrects the error, and sends it out to an external computer or the like via the interface 17. Thus, an external computer or the like can receive a signal recorded on the optical disk 11 as a reproduction signal.

The APC circuit 16 includes an optical pickup 20
The power of the light source is controlled so that the light receiving power of the light beam emitted from the light source is measured at a predetermined value.

The head access control section 18 controls the optical pickup 20 under the control of the optical disk controller 14.
Is moved to a predetermined recording track on the signal recording surface of the optical disk 11 by, for example, a track jump or the like.

Under the control of the optical disk controller 14, the servo control section 19 moves the objective lens held by the biaxial actuator of the optical pickup 20 to the signal recording surface of the optical disk 11 at this moved predetermined position. The optical disc 11 is moved in two axial directions, that is, in a separating direction (focusing) and a direction along the radial direction of the optical disc 11 (tracking direction), and focus servo and tracking servo are performed.

As shown in FIG. 2, the optical pickup 20 integrates a plurality of optical elements including a light source and a photodetector, and focuses a light beam emitted from the integrated optical element 30. Objective lens 21 as light focusing means for irradiating the signal recording surface of optical disc 11 with light
To bend the optical path of the light beam emitted from the integrated optical element 30 to the objective lens 21 and to bend the optical path of the return light beam reflected by the signal recording surface of the optical disk 11 to the integrated optical element 30. And a FAPC (Front Auto-Power-Control) photodetector 23 that receives another light beam emitted from the integrated optical element 30.

Among the light beams emitted from the light source of the integrated optical element 30, the light beam transmitted through the first beam splitter film 76 is guided to the optical disk, while the light beam reflected and separated by the first beam splitter film 76. The beam passes through the end face of the compound prism 70, exits the integrated optical element 30, and is guided to the FAPC photodetector 23. And F
The APC photodetector 23 measures the received light power of the received second light beam, and controls the laser drive current of the semiconductor laser element 31 as a light source so that the received light power has a predetermined value. This is Auto-Power-Control.

At this time, if an aperture (not shown) is provided in front of the FAPC photodetector so as to make the light incident on the FAPC photodetector 23 have a range equivalent to the spread angle incident on the objective lens 21, the laser can be used. Stable Auto-Power unaffected by divergence angle variation and output power dependence of divergence angle
-Control output is obtained.

The integrated optical element 30 is, as shown in FIG.
A semiconductor laser element 31 as a light source; a triangular prism 32 having a function of bending an optical path of a light beam emitted from the semiconductor laser element 31;
An optical member 61 made of a transparent material that transmits the laser beam whose optical path is bent by the optical fiber 2 and transmits the return light beam reflected on the signal recording surface of the optical disk 11.
And a light beam directed to the optical disk 11 and the optical disk 11
A composite prism 70 as a light separating means having a function of separating a return light beam reflected by the signal recording surface of
A photodetector IC 62 as a photodetector that receives the return light beam is provided.

Here, the semiconductor laser element 31, the triangular prism 32, and the photodetector IC 62 are provided on a substrate 37 provided in a resin package 36, as shown in FIG. Also, the resin package 36
Is provided with an opening 36a in one main surface thereof, and the resin package 36 having the opening 36a provided therein.
An optical member 61 is bonded to the main surface of the substrate with an adhesive or the like so as to close the opening 36a. further,
A composite prism 70 is bonded on the optical member 61 by an adhesive or the like. That is, the integrated optical element 30 is configured as an integrated element in which the above members are integrated. The integrated optical element 30 is fixed and held on an optical base movably supported in a radial direction of the optical disk 11 along a guide shaft (not shown).

The semiconductor laser element 31 is a light emitting element utilizing the recombination light emission of a semiconductor, and emits a laser beam (light beam) for irradiating the signal recording surface of the optical disk 11.

The triangular prism 32 has an inclined surface (reflective surface 32 a) inclined at an inclination angle of about 45 degrees with respect to the substrate 37, and the semiconductor laser device 31 moves the reflective surface 32 a from the semiconductor laser device 31 to the substrate 37. The light beam emitted in a substantially parallel direction is reflected, and its optical path is bent by about 90 degrees.

The composite prism 70 is, as shown in FIG.
First to fifth five members 71, 72, 73, 74, 7
5 are joined and integrated with an adhesive or the like, and are joined on the optical member 61.

The first member 71 is formed substantially perpendicular to the substrate 37 and an inclined surface 71a inclined at an inclination angle of about 45 degrees with respect to the substrate 37 disposed in the resin package 36. It is composed of a triangular prism having an end face 71b. The second member 72 is bonded to the first member 71 with the inclined surface 71a as a bonding surface via an adhesive. Here, the end face 71b serves as a light emitting end face when the light beam reflected and separated by the first beam splitter film 76 is emitted from the integrated optical element 60 toward the FAPC photodetector 23.

However, the first beam splitter film 76
The light beam reflected and separated by the FPC is converted to a FAPC photodetector 23.
When the light beam is emitted from the integrated optical element 60 toward the end surface, there is a problem that the light beam is reflected by the end face 71b. The light beam reflected by the end face 71b becomes unnecessary stray light, and this stray light hinders stable photodetection by the photodetector IC 62.

Therefore, in the present invention, this end face 71b is
Anti-reflection treatment is applied. As a method of performing the antireflection treatment on the end face 71b, specifically, for example, the first member 71
Forming a non-reflection coating film, a light absorbing film, or the like on the end surface 71b, but is not limited thereto as long as the reflection on the end surface 71b can be suppressed.

FIG. 6 shows a wavelength-reflectance characteristic curve of the antireflection coating film. FIG. 7 shows a wavelength-reflectance characteristic curve of the light absorbing film. As is clear from FIGS. 6 and 7, the reflectance of the non-reflection coating film and the light absorbing film for the light beam having a wavelength of 800 nm or less is 1% or less.

Therefore, by performing an anti-reflection treatment using a non-reflective coating film or a light absorbing film on the end surface 71b which is the light exit end surface of the composite prism 70, reflection on the end surface 71b is suppressed, and generation of stray light is prevented. The integrated optical element 60 can be operated stably.

The second member 72 has a pair of inclined surfaces 72a, 72b inclined at an inclination angle of about 45 degrees with respect to the substrate 37 provided in the resin package 36, and has a parallelogram cross section. Consisting of prisms. The first beam splitter film 76 is formed on one inclined surface 72a of the second member 72, and the other inclined surface 72b is formed on the other inclined surface 72b.
A second beam splitter film 77 is formed. Each of the first beam splitter film 76 and the second beam splitter film 77 is formed of a dielectric multilayer film. And
The first beam splitter film 76 is configured as a partial polarization type beam splitter, and the second beam splitter film 77 is configured as a non-polarization split type beam splitter.

The first beam splitter film 76 transmits a part of the light beam directed to the optical disk 11, reflects a part of the return light beam from the optical disk 11, and reflects the light beam directed to the optical disk 11 and the light beam from the optical disk 11. Has a function of separating the light beam from the return light beam. The first beam splitter 76 is configured as a partially-polarized beam splitter, and varies the transmittance according to the polarization direction of the incident light, so that the rotation angle of the polarization plane of the return light beam is changed. The effect of increasing the so-called car rotation angle can be exhibited.

The second beam splitter film 77 transmits through the first beam splitter film 76, transmits a part of the return light beam passing through the second member 72, and reflects another part, It has the function of separating the return light beam.

The second member 72 in which the first and second beam splitter films 76 and 77 are formed on a pair of inclined surfaces 72a and 72b, respectively, is one of the inclined surfaces on which the first beam splitter film 76 is formed. The first member 71 is joined to the inclined surface 71a of the first member 71 via an adhesive, with 72a serving as a joining surface for the first member 71. Also, the second member 72
The third member 73 is bonded via an adhesive with the other inclined surface 72b on which the second beam splitter film 77 is formed as a bonding surface.

The third member 73 has a pair of inclined surfaces 73 a and 73 b in which artificial quartz or the like is inclined at an inclination angle of about 45 degrees with respect to the substrate 37 provided in the resin package 36. Is a half-wave plate shaped so as to form a parallelogram. As shown in FIG. 8, the third member 73 made of the half-wave plate has an optical axis azimuth in which the rotation φ in the plane is about 20 ° and the angle between one inclined surface 73a and the optical axis. It is desirable that θ be set to be about 13.8 °. As described above, in the optical axis direction of the third member 73 made of a half-wave plate, the rotation φ in the plane is about 20 °, and the angle θ between the one inclined surface 73a and the optical axis is about 13.8. °, the phase shift due to the refractive index difference corresponding to the difference in the incident position of each part of the return light beam obliquely incident on the third member 73 can be corrected. it can.

The third member 73 made of this half-wave plate is
It has a function of rotating the polarization plane of the return light beam reflected by the signal recording surface of the optical disk 11 and transmitted through the first and second beam splitters 76 and 77 by 45 °.

The third member 73 made of the half-wave plate is
The second beam splitter film 77 of the second member 72 is formed by using one of the inclined surfaces 73a as a bonding surface to the second member 72.
Is bonded via an adhesive to the other inclined surface 72b on which is formed. The third member 7 made of the half-wave plate
In No. 3, a fourth member 74 is bonded via an adhesive with the other inclined surface 73b as a bonding surface.

The fourth member 74 has a pair of inclined surfaces 74a, 74b inclined at an inclination angle of about 45 degrees with respect to the substrate 37 disposed in the resin package 36, and has a parallelogram cross section. Consisting of prisms. A polarization beam splitter film 78 is formed on the other inclined surface 74b of the fourth member 74.

The polarization beam splitter film 78 is made of a dielectric multilayer film, and completely separates incident light according to its polarization direction by the multiple interference effect. That is, the polarizing beam splitter film 78 is designed to transmit almost 100% of the P-polarized light component parallel to the incident surface and reflect almost 100% of the S-polarized light component perpendicular to the incident surface.

A return light beam whose polarization plane is rotated by 45 ° by transmitting through a third member 73 made of a half-wave plate is transmitted to a fourth member 74 of the polarization beam splitter film 78.
Incident on the lens. In the composite prism 70, as described above, the polarization plane is changed to 4 by the third member 73.
By making the return light beam rotated by 5 ° incident on the polarization beam splitter film 78 and separating it by polarization, it is possible to detect a magneto-optical signal (MO) by so-called 45 ° MO differential detection.

The fourth member 74 in which the polarization beam splitter film 78 is formed on the other inclined surface 74 b is formed by using the one inclined surface 74 a as a joining surface to the third member 73 and using the other inclined surface of the third member 73. It is joined to the surface 73b via an adhesive. The fifth member 75 is bonded to the fourth member 74 via an adhesive with the other inclined surface 74b on which the polarizing beam splitter film 78 is formed as a bonding surface.

The fifth member 75 has a pair of inclined surfaces 75a, 75b inclined at an inclination angle of about 45 degrees with respect to the substrate 37 provided in the resin package 36, and has a parallelogram cross section. Consisting of prisms. The other inclined surface 75b of the fifth member 75 is a reflection surface that reflects the return light beam transmitted through the polarization beam splitter film 78.

The fifth member 75 has one inclined surface 75.
“a” is a bonding surface to the fourth member 74, and is bonded via an adhesive to the other inclined surface 74 b of the fourth member 74 on which the polarizing beam splitter film 78 is formed.

The composite prism 70 constructed as described above
In the above, the first beam splitter film 76 formed on one inclined surface 72a of the second member 72 has a function of separating the light beam heading for the optical disk 11 and the light beam returning from the optical disk 11.

In the composite prism 70,
A second member 72 formed on the other inclined surface 72b of the second member 72
The beam splitter film 77, the third member 73 made of a half-wave plate, and the polarization beam splitter film 78 formed on the other inclined surface 74b of the fourth member 74 were separated by the beam splitter film 40a. It has a function of splitting the return light beam.

Further, in the composite prism 70, the other inclined surface 75b of the fifth member 75 is
2a, which has a function of reflecting the return light transmitted through the polarization beam splitter film 78.

Since the composite prism 70 is formed by joining and integrating the components having the above functions, it contributes to the miniaturization of the optical pickup, and also reduces the number of parts and the parts and assembly costs. can do.

The composite prism 70 configured as described above is composed of flat first to fifth members 71, 72, and 7.
Since it is obtained by sequentially stacking 3, 74, and 75, and obliquely cutting and laminating a stacked body obtained by stacking them, manufacturing is very easy.

In this composite prism 70,
Since the first beam splitter film 76 and the second beam splitter film 77 are both formed on the inclined surfaces 72a and 72b of the second member, which is a single member, the first beam splitter film 76 and the second beam splitter film 77 The distance between the second beam splitter film 77 and the second beam splitter film 77 can be accurately controlled without being affected by uncertain factors such as the thickness of the adhesive. Therefore, in the optical pickup using the composite prism 70, the optical path length of the light beam emitted from the semiconductor laser element 31 and transmitted through the first beam splitter film 76 is reflected by the first beam splitter film 76, The optical path length of the return light reflected by the second beam splitter film 77 and received by the light receiving section of the photodetector IC 62 is made to exactly match the optical path length, and a focus error signal (FE)
Can be appropriately detected.

Further, in the composite prism 70, since an anti-reflection treatment is applied to an end face 71b which is a light emission end face of the Auto-Power-Control light beam, reflection on the end face 71b is suppressed, and generation of stray light is suppressed. Is prevented, and the integrated optical element 60 can be operated stably.

The optical member 61 is formed, for example, by molding a transparent plastic material or glass into a parallel plate. The optical member 61 is reflected by the triangular prism 32 and located on the first optical path L1 which is the optical path of the light beam traveling toward the composite prism 70. A coupling lens 64 as a means is integrally formed.

The optical member 61 has a second optical path L 2, which is an optical path of a return light beam toward the photodetector IC 62, separated by the composite prism 70.
The optical path of the return light beam reflected by the second beam splitter film 77 of the composite prism 70 (hereinafter, the third optical path L
Three. ), A cylindrical lens 65 as a focus error signal generating means is integrally formed.

Further, in the optical member 61, of the second optical path L2, the optical path of the return light beam reflected by the polarization beam splitter film 78 of the composite prism 70 (hereinafter, referred to as a fourth optical path L4). Top and fifth of composite prism 70
A concave lens 66 as a beam diameter adjusting means is integrally formed on the optical path (hereinafter, referred to as a fifth optical path L5) of the return light beam reflected by the inclined surface 75b of the member 75.

The grating 63 is a diffraction grating for diffracting incident light. For example, a portion of the lower surface 61b of the optical member 61 (surface joined to the resin package 36) through which a light beam passes, that is, a first optical path Built on L1.

The coupling lens 64 is for converting the divergence angle of the light beam emitted from the semiconductor laser device 31. For example, the coupling lens 64 is provided for the upper surface 561a of the optical member 61.
It is formed as a convex lens on the portion where the light beam passes (the surface to which the composite prism 70 is bonded), that is, on the first optical path L1.

The optical pickup is a semiconductor laser device 3
1 is a first optical path L1 which is an optical path of a light beam emitted from
Coupling lens 6 for converting the divergence angle of the light beam
By arranging 4, the divergent light beam emitted from the semiconductor laser element 31 can be narrowed down to some extent and guided to the objective lens 21. Therefore, by using the coupling lens 64 in the optical pickup, it is possible to use a finite magnification objective lens as the objective lens 21 while securing the light intensity of the laser light required for recording. The optical pickup can be further miniaturized by using a finite magnification objective lens as the objective lens 21, and a means for converting divergent light into parallel light like a collimator lens is not required, and the number of parts is reduced. Can be reduced.

The cylindrical lens 65 imparts astigmatism to the incident light and adjusts the optical path length. For example, the second lens splitter film 77 on the upper surface 61 a of the optical member 61 is provided. Is formed on the portion where the return light beam reflected by the light is transmitted, that is, on the third optical path L3. The cylindrical lens 65 imparts astigmatism to the return light beam reflected by the second beam splitter film 77 in order to enable detection of a focus error signal by a so-called astigmatism method.

The concave lens 66 is the second lens of the composite prism 70.
The optical path length of the return light beam reflected by the beam splitter film 77, transmitted through the optical member 61 through the third optical path L3, and received by the light receiving portion of the photodetector IC 62, and the polarization beam splitter film of the composite prism 70 The optical path length of the return light beam reflected by the second light path 78, transmitted through the optical member 61 through the fourth optical path L4, and received by the light receiving section of the photodetector IC 62, and the fifth path of the composite prism 70
Is reflected by the inclined surface 75b of the member 75, passes through the optical member 61 through the fifth optical path L5, and adjusts the deviation from the optical path length of the return light beam received by the light receiving section of the photodetector IC 62. This is to enable the return light beam to form an appropriate spot on the light receiving portion of the photodetector IC 62.

The concave lens 66 is formed, for example, at a position where the return light beam reflected by the polarization beam splitter film 78 is transmitted, that is, on the fourth optical path L 4 and the fifth member 7.
It is integrally formed on the upper surface 61a of the optical member 61 over a portion where the return light beam reflected by the fifth inclined surface 75b is transmitted, that is, on the fifth optical path L5.

The return light reflected by the polarizing beam splitter film 78 of the composite prism 70 and the return light reflected by the inclined surface 75b of the fifth member 75 of the composite prism 70 pass through the concave lens 66, respectively. Spread. Thereby, the optical path length of each return light beam received by the light receiving portion of the photodetector IC 62 is adjusted, and the spot of each return light beam is appropriately formed on the light receiving portion of the photodetector IC 62.

The photodetector IC 62 includes a return light beam reflected by the second beam splitter film 77 of the composite prism 70 and a return light beam transmitted through the second beam splitter film 77 and reflected by the polarization beam splitter film 78. Through the polarizing beam splitter film 78,
A photodetector for receiving the return light beam reflected by the inclined surface 75a of the fifth member 75; and a voltage conversion circuit for converting a current from the photodetector to a voltage. It is configured as

The photo detector section of the photo detector IC 62 has five light receiving sections F to J as shown in FIG. One of the light receiving units F to J of the light receiving units F to J
Is divided by two split lines that cross vertically and horizontally,
Further, it is divided into four light receiving portions F1, F2, F3, and F4.

The photodetector section irradiates the signal recording surface of the optical disc 11 with the light receiving section divided by the grating 63 by these light receiving sections. Each of the polarization split return light beams is received. That is, the third optical path L3
The return light beams that have reached the photodetector IC 62 through the light detectors F, G, and H of the photodetector unit are respectively received by the light receiving units F, G, and H. The return light beam received by the section I and reaching the photodetector IC 62 through the fifth optical path L5 is received by the light receiving section J of the photodetector section.

The current value based on the amount of return light received by each light receiving unit of the photodetector unit is converted into a voltage value by a voltage conversion circuit, and is received as a light receiving signal by, for example, the signal demodulator 15 of the optical disk device described above. Supplied.

Here, each light receiving section F1, F2, F3, F4 of the photo detector section of the photo detector IC 62
The light receiving signals based on the light received by G, H, I, J are respectively SF1, SF2, SF3, SF4, SG, S
Assuming that H, SI, and SJ, the magneto-optical signal MO, the pit reproduction signal Pit, the focus error signal FE, and the tracking error signal TE are respectively obtained by the following arithmetic expressions.

MO = SI-SJ Equation 1 Pit = SI + SJ Equation 2 FE = (SF1 + SF3)-(SF2 + SF4) Equation 3 TE = SG-SH Equation 4 Configuration as above In an optical pickup having an integrated optical element 60, a grating 63 as a light splitting unit, a coupling lens 64 as a light beam adjusting unit, a hologram 65 as a focus error signal generating unit, and a concave lens as a beam diameter adjusting unit Since 66 is formed integrally with the optical member 61, it is not necessary to separately provide these as individual optical elements. Therefore,
In this optical pickup, the number of components is reduced and the size of the entire device is reduced because these components are not provided as individual optical elements.
Further, when assembling the optical pickup, it is not necessary to individually position the light splitting means, the light beam adjusting means, the focus error signal generating means and the beam diameter adjusting means, so that the assembling work can be simplified. become.

Also, in this optical pickup,
Since the members except the objective lens 21 and the rising mirror 22 are integrated and configured as an integrated optical element 60, only the integrated optical element 60, the objective lens 21, and the rising mirror 22 are assembled during assembly. It suffices to assemble while aligning, so that the assembling work can be simplified and the assembling cost can be reduced.

Further, in this optical pickup, since the anti-reflection processing is performed on the light exit surface of the compound prism 70, generation of unnecessary stray light based on the light reflected on the light exit surface can be suppressed.

[0097]

According to the integrated optical device of the present invention,
Since the integrated optical elements are integrated and integrated with each other, and the focus error signal generating means is formed integrally with the optical member, the overall size can be reduced and the number of parts can be reduced. Will be done.

Further, in the optical pickup according to the present invention, the light source and the photodetector of the integrated optical element are integrally formed and provided on, for example, one substrate, so that the lead wire for extracting the signal is provided. , The assembly work is simplified, the assembly cost is reduced, and the mutual alignment between the light source and the photodetector is not required.

Further, in the optical pickup according to the present invention, since the anti-reflection treatment is performed on the light exit surface of the integrated optical element, it is possible to suppress the generation of unnecessary stray light based on the light reflected on the light exit surface. And can operate stably.

In the optical disk apparatus according to the present invention, the integrated optical element is formed by integrating each optical element and the focus error signal generating means is formed integrally with the optical member. And miniaturization of the optical disk device is realized,
The number of parts can be reduced.

Further, in the optical disk device according to the present invention, the light source and the photodetector of the integrated optical element are integrally formed and provided on, for example, one substrate, so that a lead wire for extracting a signal is provided. , The assembly work is simplified, the assembly cost is reduced, and the mutual alignment between the light source and the photodetector is not required.

Further, in the optical disk device according to the present invention, since the light exit surface of the integrated optical element is subjected to antireflection processing, it is possible to suppress the generation of unnecessary stray light based on the light reflected on the light exit surface. And can operate stably.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of an optical disc device according to the present invention.

FIG. 2 is a perspective view schematically showing one configuration example of an optical pickup provided in the optical disk device.

FIG. 3 is a schematic view showing an example of an integrated optical element provided in the optical pickup.

FIG. 4 is a diagram illustrating a positional relationship among a semiconductor laser element, a triangular prism, and a photodetector IC included in the integrated optical element.

FIG. 5 is an exploded side view showing a composite prism included in the integrated optical element.

FIG. 6 is a diagram showing a relationship between a light beam wavelength and a reflectance of a non-reflection coating film.

FIG. 7 is a diagram showing a relationship between a light beam wavelength and a reflectance of a light absorbing film.

FIG. 8 is a diagram illustrating an optical axis direction of a third member (half-wave plate) of the composite prism.

FIG. 9 is a photodetector I included in the integrated optical element.
It is a top view which shows C typically.

FIG. 10 is a perspective view schematically showing one configuration example of a conventional optical pickup.

[Explanation of symbols]

10 optical disk device, 11 optical disk, 20
Optical pickup, 21 objective lens, 22 rising mirror, 23 photodetector for AFPC, 30 integrated optical element

Claims (10)

[Claims] 1. An optical pickup for irradiating a signal recording surface of an optical disc with a light beam to record and / or reproduce a signal, comprising: an integrated optical element; A light focusing means for irradiating a recording surface of the optical disk, wherein the integrated optical element emits a light beam for irradiating the signal recording surface of the optical disk, and a return light beam reflected by the signal recording surface of the optical disk. A photodetector for receiving light, a package member having an opening in one main surface thereof and accommodating the light source and the photodetector therein, respectively, provided on a main surface having an opening of the package member. An optical member that transmits a light beam emitted from the light source and transmits a return light beam toward the photodetector; and an optical member provided integrally with the optical member; Light separating means for separating a light beam emitted from a source and a returning light beam toward the photodetector, wherein the optical member includes return light separated by the light separating means and traveling toward the photodetector. Located on the beam path,
Focus error signal generating means for generating a focus error signal is integrally formed. Further, the light separating means has a light emitting surface on which a light beam emitted from the light source and transmitted through the light separating means is emitted. An optical pickup characterized by being subjected to anti-reflection treatment. 2. The optical pickup according to claim 1, wherein the anti-reflection treatment is performed by a non-reflection coating film formed integrally with the light separating means. 3. The optical pickup according to claim 1, wherein the anti-reflection processing is performed by a light absorbing film formed integrally with the light separating means. 4. A return light transmitted between the integrated optical element and the light focusing means, while reflecting a light beam from the integrated optical element toward the light focusing means and passing through the light focusing means. 2. The optical pickup according to claim 1, further comprising a reflection member for reflecting the light toward the integrated optical element. 5. An optical pickup for irradiating a signal recording surface of an optical disk with a light beam to record and / or reproduce a signal, wherein the integrated pickup emits a first light beam and a second light beam. An optical element; a light focusing means for focusing the first light beam emitted from the integrated optical element to irradiate the signal recording surface of the optical disk; and a second light beam emitted from the integrated optical element. A first photodetector that receives light and controls an output of a light beam emitted from a light source included in the integrated optical element in accordance with the power of the second light beam; A light source for emitting a light beam for irradiating the signal recording surface of the optical disc, a second photodetector for receiving a return light beam reflected on the signal recording surface of the optical disc, and an opening in one main surface portion Inside, on A package member accommodating the light source and the second photodetector, respectively, provided on a main surface having an opening of the package member, and transmitting a light beam emitted from the light source; An optical member that transmits a return light beam toward the photodetector; and an optical member that is provided integrally with the optical member and separates the light beam emitted from the light source into a first light beam and a second light beam. And a light separating means for separating a first light beam and a return light beam toward the second light detector, wherein the optical member has the second light separated by the light separating means. Focus error signal generating means for generating a focus error signal is formed integrally on the optical path of the return light beam toward the detector, and the light separating means further comprises: The light emitting surface of the second light beam transmitted through the means for emitting an optical pickup characterized in that the anti-reflection treatment is applied. 6. The optical pickup according to claim 5, wherein said anti-reflection treatment is performed by a non-reflection coating film formed integrally with said light separating means. 7. A first light beam from the integrated optical element is reflected between the integrated optical element and the light focusing means to be directed to the light focusing means and transmitted through the light focusing means. 6. The optical pickup according to claim 5, further comprising a reflecting member for reflecting the returning light and directing the returning light toward the integrated optical element. 8. A divergence angle of a second light beam incident on the first photodetector between the integrated optical element and the first photodetector, the divergence angle of the second light beam incident on the light converging means. 6. The optical pickup according to claim 5, further comprising: an optical aperture control unit that makes the divergence angle of the one light beam substantially equal. 9. An optical pickup for irradiating a signal recording surface of an optical disk with a light beam and detecting return light from the signal recording surface of the optical disk, and based on a detection signal from a photodetector provided in the optical pickup. A signal processing circuit for generating a reproduction signal, the optical pickup comprising: an integrated optical element; and a light focusing means for focusing the light beam and irradiating the signal recording surface of the optical disc with the integrated optical element. The element includes a light source that emits a light beam for irradiating the signal recording surface of the optical disc, a photodetector that receives a return light beam reflected on the signal recording surface of the optical disc, and an opening in one main surface. A package member that contains therein the light source and the photodetector, respectively, and is provided on a main surface having an opening of the package member, An optical member that transmits a light beam emitted from a light source and transmits a return light beam toward the photodetector; and an optical member that is provided integrally with the optical member and that detects the light beam emitted from the light source and the light detection. Light separating means for separating the return light beam toward the detector, and the optical member is located on the optical path of the return light beam toward the photodetector separated by the light separating means,
Focus error signal generating means for generating a focus error signal is integrally formed. Further, the light separating means has a light emitting surface on which a light beam emitted from the light source and transmitted through the light separating means is emitted. An optical disc device, which has been subjected to anti-reflection processing. 10. An optical pickup for irradiating a signal recording surface of an optical disk with a light beam and detecting return light from the signal recording surface of the optical disk, and detecting the light from a first photodetector provided in the optical pickup. Control means for controlling an output of a light beam emitted from a light source provided in the optical pickup based on the signal; and a reproduction signal generated based on a detection signal from a second photodetector provided in the optical pickup. A signal processing circuit, wherein the optical pickup comprises: an integrated optical element that emits a first light beam and a second light beam; and an optical element that focuses the first light beam emitted from the integrated optical element. A light focusing means for irradiating a signal recording surface of the optical disk, and a second light beam emitted from the integrated optical element is received, and the power of the second light beam is reduced. A first light detector for controlling the output of a light beam emitted from a light source included in the integrated optical element, wherein the integrated optical element emits a light beam for irradiating a signal recording surface of the optical disk. A light source; a second photodetector for receiving a return light beam reflected by the signal recording surface of the optical disc; and an opening in one main surface portion, wherein the light source and the second photodetector are inside. And a package member for accommodating each of the devices, and a return light beam provided on a main surface portion having an opening of the package member, transmitting a light beam emitted from the light source, and traveling toward the second photodetector. An optical member that transmits light, a light beam emitted from the light source is separated into a first light beam and a second light beam, and the first light beam Up Light separating means for separating the return light beam toward the second photodetector, wherein the optical member has a light of the return light beam separated by the light separating means and traveling toward the second photodetector. Focus error signal generation means for generating a focus error signal is formed integrally on the road, and a second light beam transmitted through the light separation means is emitted to the light separation means. An optical disc device, wherein an anti-reflection process is performed on a light emitting surface.