JP2001076363A - Hologram element, optical integrated element, optical pickup, and optical information processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To diffuse unintended light in various directions or to restrain its reflection and t reduce the incidence of a stray light to a light receiving element by applying a stray light treatment for reducing the regular reflection of incident light to the incident surface, the exiting surface or the side surface of a laser beam excepting a diffracted pattern. SOLUTION: Laser beams LA, LB emitted from laser diode chips 12A, 12B are diffracted by the light source side hologram 18A of a hologram element 18 and are emitted after being reflected by a right angle prism 15, and return light is diffracted by an objective lens side hologram 18C and is received. Thus, various degrees of unintended diffracted light beams excepting the objective diffracted light beam are generated in an optical integrated element 12, and the unintended diffracted light beams are possibly to be reflected as a stray light by respective surfaces of the hologram element 18 and to make incident on light receiving elements 16A, 16B. Thereupon, the surfaces excepting the holograms 18A, 18C of the hologram element 18 are roughened and are subjected to a stray light treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a hologram element,
The optical integrated device, the optical pickup, and the optical information processing device can be applied to, for example, an optical disk device for reproducing a compact disk, a DVD, and the like. The present invention reduces the incidence of stray light on a light receiving element even in an optical pickup using an optical integrated element by performing a stray light process for reducing the regular reflection of incident light on a hologram element applied to the optical integrated element. To be able to.

[0002]

2. Description of the Related Art Conventionally, in an optical disk apparatus, data recorded on an optical disk is reproduced by irradiating an optical disk with a laser beam of a predetermined wavelength from an optical pickup and receiving the return light.

FIG. 7 is a sectional view showing an optical pickup for accessing a DVD. In the optical pickup 1, the laser diode 2 emits a laser beam LA having a wavelength of 650 [nm] for DVD.

[0004] The beam splitter 3 transmits the laser beam LA emitted from the laser diode 2, and reflects the returning light incident on the laser beam LA by reversely following the optical path of the laser beam LA toward the light receiving element 4.

[0005] The collimator lens 5 converts the laser beam LA arriving from the beam splitter 3 into a substantially parallel light beam and emits it. The collimator lens 5 reversely follows the optical path of the laser beam LA and converts the incoming return light into a convergent light beam. Out. The mirror 6 emits the laser beam LA emitted from the collimator lens 5 toward the DVD 7, and emits the return light incident on the laser beam LA by reversely following the optical path of the laser beam LA toward the collimator lens 5.

The aperture 8 emits the laser beam LA reflected by the mirror 6 with the beam diameter limited to a predetermined value, and the objective lens 9 transmits the laser beam LA emitted from the aperture 8 to the information recording surface of the DVD 7. Focus on

As a result, in the optical pickup 1, return light that changes according to the pit row formed on the information recording surface is obtained, and this return light passes through the objective lens 9, the opening 8, the mirror 6, and the collimator lens 5. The beam enters the beam splitter 3 through the optical path, and is reflected by the beam splitter 3 toward the light receiving element 4.

The multi-lens 10 decomposes the return light emitted from the beam splitter 3 into a plurality of light fluxes required for processing the return light, and emits the light. The light receiving element 4 converts the return light from the plurality of light fluxes. Receives light and outputs the result.
Thus, in the optical disk device, the light receiving element 4
Are processed to perform tracking control and focus control of the objective lens 9 and to reproduce data recorded on the DVD 7.

In such an optical pickup 1,
Due to reflections on optical components such as the laser diode 2, the mirror 6, and the objective lens 9, and reflections on a bonding surface of a base material that adheres and holds these optical components, part of the laser beam LA, return light, and the like are unplanned. May be received by the light receiving surface of the light receiving element 4 following the optical path of the light receiving element 4. Such light (so-called stray light) is light that is not intended to be received by the light receiving element 4. In an optical disc apparatus, when stray light is received by the light receiving element 4, recording and reproduction are performed accordingly. And other characteristics will be degraded.

In the optical pickup 1, since the source of the stray light and the light receiving side of the stray light are separated from each other, the stray light is prevented by the anti-reflection processing of the optical components and the base material on the source side of the stray light. The light is prevented from being incident on the light receiving element 4 so that the optical disk can be securely accessed.

[0011]

In recent years, in this type of optical disk device, an optical pickup is formed by using an optical integrated element in which a light emitting element and a light receiving element are integrated, and the overall structure is simplified accordingly. Some have been made to do so.

In such an optical integrated device, since the light emitting device and the light receiving device are integrated with each other, stray light is generated by the device itself. There is a problem that it is not possible to prevent the light from being incident on the light receiving element depending on the stray light countermeasures based on the premise that the light receiving side of the stray light and the stray light receiving side are separated.

The present invention has been made in view of the above points, and a hologram element capable of reducing the incidence of stray light on a light receiving element even in an optical pickup using an optical integrated element, An optical integrated device, an optical pickup, and an optical information processing device using the same are proposed.

[0014]

According to the first aspect of the present invention, there is provided a hologram element applied to an optical integrated element, wherein an incident surface or an exit surface of a laser beam excluding a diffraction pattern is provided. Alternatively, the side surface is subjected to stray light processing for reducing the regular reflection of incident light.

According to the fifth, ninth, or thirteenth aspect of the present invention, the present invention is applied to an optical integrated device, an optical pickup, or an optical information processing device, and an incident surface or an exit of a laser beam excluding a diffraction pattern in a hologram element. The surface or the side surface is subjected to a stray light treatment for reducing specular reflection of incident light.

According to the first aspect of the present invention, the present invention is applied to a hologram element applied to an optical integrated element, and a regular reflection of incident light is made on an incident surface or an exit surface or a side surface of a laser beam excluding a diffraction pattern. By performing the stray light processing to reduce the light, unintended light incident on the entrance surface, the exit surface, and the side surface of the hologram element is scattered in various directions or the reflection is suppressed. Reduced. Thereby, the incidence of stray light on the light receiving element can be reduced.

According to the fifth, ninth, or thirteenth aspect, the present invention is applied to an optical integrated device, an optical pickup, or an optical information processing device, and a laser beam incident surface excluding a diffraction pattern in a hologram element. Or, on the exit surface, or on the side surface, by performing stray light processing to reduce the regular reflection of the incident light, the incident surface of the hologram element, the exit surface, in unintended light incident on the side surface, is scattered in various directions, or The reflection is suppressed, and the incidence on the light receiving element is reduced. Thereby, the incidence of stray light on the light receiving element can be reduced.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(1) First Embodiment (1-1) Configuration of First Embodiment FIG. 2 is a cross-sectional view showing an optical pickup applied to an optical disk device according to a first embodiment of the present invention. FIG. In the configuration of the optical pickup 11, the same components as those of the optical pickup 1 described above with reference to FIG. 7 are denoted by the corresponding reference numerals, and redundant description will be omitted.

In the optical pickup 11, the optical integrated element 12 emits a laser beam LA having a wavelength of 650 [nm] for DVD when the DVD 13A is loaded in the optical disk device under the control of a control circuit (not shown). On the other hand, when the compact disc 13B is loaded, a laser beam LB having a wavelength of 785 [nm] for the compact disc is emitted. Further, the optical integrated device 12
The return light by the laser beams LA and LB having the wavelengths of 650 [nm] and 785 [nm] is received, and the light reception result is output.

In the optical pickup 11, after the optical paths of the laser beams LA and LB emitted from the optical integrated device 12 are bent by the beam splitter 3, the optical paths are further bent by the mirror 6 and incident on the objective lens 9.
Thereby, the overall shape is reduced in size.
The optical pickup 11 emits the laser beams LA and LB toward the objective lens 9 using divergent light that is closer to parallel light than the collimator lens 5.

Further, the optical pickup 11 has an opening 14 between the objective lens 9 and the mirror 6. The opening 14 is a wavelength-selective opening formed by laminating a transparent dielectric film on a transparent flat plate member. In the central circular area, the laser beam LA for DVD and the laser beam for compact disc are used. While transmitting both LBs, only the DVD laser beam LA is transmitted in the outer region except for the central circular region,
The laser beam LB for the compact disk is shielded.

As a result, this optical pickup 11
The VD laser beam LA irradiates the DVD 13A with a numerical aperture of 0.6, and the compact disk laser beam LB irradiates the compact disk 13B with a numerical aperture of 0.45.

The opening 14 is configured such that the entire end is inclined about 4 degrees with respect to a plane perpendicular to the optical axis of the objective lens 9 so that the end on the collimator lens 5 side is close to the collimator lens 5 side. Accordingly, the laser beam LB emitted from the opening 14 is prevented from becoming stray light and entering the light receiving element of the optical integrated element 12.

FIG. 1 is a sectional view showing the optical integrated device 12 in detail. The optical integrated element 12 is an optical element in which a light source for emitting a laser beam and a light receiving element for receiving return light obtained from an optical disc as an optical information recording medium by irradiation of the laser beam are integrated. In the embodiment, laser diode chips 12A and 12B that emit laser beams LA and LB, respectively, are applied to a light source.

In the optical integrated device 12, the laser diode chips 12A and 12B are housed in a package P.
Further, the laser diode chips 12A, 12B are opposed to the laser diode chips 12A, 12B.
A right-angle prism 15 for raising laser beams LA and LB emitted from 2B is arranged. Further, in the optical integrated device 12, light receiving devices 16A and 16B for DVD and compact disk are respectively housed in a package P,
This package P is sealed by the cover glass 17. In the optical integrated device 12, a hologram element 18 is held on the cover glass 17 by bonding, and the hologram element 18 separates the laser beams LA and LB into predetermined light beams and emits the same. And receive light separately.

That is, taking the compact disk laser beam LB as an example, and omitting the prism 15, the laser beam LA is emitted directly from the laser diode chip 12B, as shown in FIG. The hologram element 18 is formed into a substantially rectangular parallelepiped shape by injection molding a transparent resin. This hologram element 18
A hologram 18A is formed in which a concave portion is formed on the side of the cover glass 17 (FIG. 1), and the laser beam LB that penetrates and enters the concave portion of the cover glass 17 is diffracted. As a result, the hologram element 18 produces the −1 order, 0 order,
The first-order diffracted light is emitted, and tracking control can be performed by a so-called three-spot method.

The hologram element 18 has a hologram 18 on the surface opposite to the cover glass 17 for diffracting return light.
C is created. Here, the hologram 18C divides the return light by two regions 18CA and 18CB having different diffraction angles and receives the light, whereby the light receiving element 16B determines the light reception result between the light beams corresponding to the two regions 18CA and 18CB. By performing the processing, focus control can be performed by the so-called Foucault method.

Thus, in the light receiving element 16B, the light receiving surface for receiving the return light by the main beam is divided into crosses (denoted by A to D), whereby the divided light receiving surfaces A to D are divided. By processing the light receiving results of (1) and (2), it is possible to detect a focus error signal whose signal level changes according to the focus error amount and a reproduction signal whose signal level changes according to the pit train. Also, on both sides of the light receiving surface that receives this main beam,
Light receiving surface E for receiving return light by a so-called side beam
And F are formed, and by processing the light receiving results of the light receiving surfaces E and F, a tracking error signal whose signal level changes according to the tracking error amount can be generated.

The hologram element 18 forms a hologram on the surface opposite to the cover glass 17 with respect to the DVD laser beam LA, and the hologram and the light receiving element 16A have a focus error by a so-called spot size detection method. A signal can be generated, and further, a tracking error signal can be generated by a so-called DPP method.

The holograms 18A and 18
The hologram element 18 in which C is formed is subjected to stray light processing for reducing the regular reflection of incident light on the surface (indicated by the symbol X) on the beam splitter 3 side. 16B.

In this embodiment, the surface of the hologram element 18 on the side of the beam splitter 3 is roughened by machining of a mold used for injection molding or by post-processing after injection molding. The processing is performed.

(1-2) Operation of the First Embodiment In the above configuration, in the optical disk device according to this embodiment, when the DVD 13A is loaded, the optical pickup 11 (FIG. 2) Laser beam LA for DVD with wavelength 650 [nm] from element 12
Is emitted, and this laser beam LA is reflected by the beam splitter 3 and is converted by the collimator lens 5 into divergent light close to a parallel light beam. Further, the light LA emitted from the collimator lens 5 is reflected by the mirror 6, the optical path is bent, and the light is focused on the DVD 13A by the objective lens 9.

The return light obtained by irradiating the DVD 13A with the laser beam LA in this manner is guided to the optical integrated device 12 by following the optical path of the laser beam LA in reverse.
This return light is split into a plurality of light beams by the optical integrated element 12 and received by the built-in light receiving element 16A (FIG. 1).
The objective lens 9 is subjected to tracking control and focus control by processing the received light result, and the data recorded on the DVD 13A is reproduced.

On the other hand, when the compact disk 13B is loaded, the optical disk device uses a wavelength of 785 [n].
m] for compact disc laser beam LB
Is emitted from the optical integrated device 12, and this laser beam L
After B is reflected by the beam splitter 3, it is converted by the collimator lens 5 into divergent light close to a parallel light. Further, the light LB emitted from the collimator lens 5 is reflected by the mirror 6, the optical path is bent, and the light is focused on the compact disk 13B by the objective lens 9. Further, the return light obtained as a result is guided to the optical integrated device 12 in the same manner as in the case of the DVD 13A, and is received and processed there, whereby the tracking control and the focus control of the objective lens 9 are performed. Is reproduced.

Thus, the compact disc 13B
The laser beam LB applied to the aperture 14
Limits the beam diameter, which results in a numerical aperture of 0.45
Thus, the data recorded on the compact disc 13B can be reproduced with a sufficient tilt margin.

Further, in this manner, the optical disks 13A, 1
The laser beams LA and LB applied to the 3B are partially reflected by the opening 14 and cause stray light. In this embodiment, however, the opening 14 is tilted by a small angle. The stray light generated by the reflection at the opening 14 is reflected in a direction that does not enter the light receiving elements 16A and 16B, thereby preventing deterioration of characteristics due to the stray light.

Thus, the laser beams LA and L
B, and light receiving elements 16A and 16B for receiving return light
(FIG. 1), the laser diode chip 12
The laser beams LA and LB emitted from A and 12B are reflected by the right-angle prism 15 and then diffracted and emitted by the hologram element 18A on the light source side of the hologram element 18, and the hologram 18C on the objective lens side is returned.
Is diffracted and received. Thereby, the optical integrated device 1
In No. 2, unintended diffracted light of various orders other than the intended diffracted light is generated, and the unintended diffracted light is reflected on each surface of the hologram element 18 as stray light and enters the light receiving elements 16A and 16B. There is fear. Furthermore, a part is reflected at the interface of the cover glass 17 and the like,
These may also be reflected as stray light on each surface of the hologram element 18 and enter the light receiving elements 16A and 16B.

In the light generated inside the optical integrated device 12 and received by the light receiving elements 16A and 16B,
A stray light countermeasure method based on the premise that the stray light source and the stray light receiving side are separated from each other as in the conventional optical pickup 1 cannot prevent the light receiving elements 16A and 16B from receiving the stray light.

However, in this embodiment, the stray light processing for reducing the regular reflection of the incident light is performed on the exit surface X side of the hologram element 18, and thus the light is generated inside the optical integrated element 12. Of the stray light generated, the component incident on the emission surface X is the light receiving element 16A,
The amount of light incident on 16B can be reduced, and deterioration of various characteristics due to the reception of stray light can be prevented.

Actually, when a hologram is formed on the entrance / exit surface of the hologram element 18 to process a laser beam and return light as in this embodiment, the hologram element 18
In this case, the light receiving elements 16A, 1
It is necessary to ensure an interval between the right-angle prism 6B and the right-angle prism 15, and in such a case, in the stray light incident on the light receiving elements 16A and 16B, the component that is regularly reflected on the exit surface of the hologram element 18 becomes almost.

In this embodiment, the stray light processing is performed by partially roughening the exit surface, so that the hologram is formed by the same molding step as that in the case where no stray light processing is performed, for example, by processing a mold. Element 18 can be made.

Thus, in this embodiment, the reception of stray light can be reliably reduced with a simple configuration, and the deterioration of various characteristics due to the reception of this stray light can be prevented.

(1-3) Effects of the First Embodiment According to the above configuration, stray light processing for reducing the regular reflection of incident light is performed on the exit surface of the hologram element 18 constituting the optical integrated element 12. Therefore, even in an optical pickup using the optical integrated element 12, the light receiving elements 16A and 16B
Incident of stray light can be reduced, and deterioration of various characteristics can be prevented accordingly.

Specifically, deterioration of jitter can be prevented,
Further, it is possible to expand various margins at the time of recording / reproducing, and it is possible to prevent erroneous detection of various control signals when seeking the optical pickup.
Further, there is no need to cancel stray light on the signal processing circuit side, and the configuration of the signal processing circuit can be simplified accordingly.

At this time, the light-emitting element 1 has a simple structure by partially roughening the emission surface and performing stray light processing.
The incidence of stray light on 6A and 16B can be reduced.

(2) Second Embodiment FIG. 4 is a sectional view showing an optical integrated device applied to an optical disk device according to a second embodiment of the present invention in comparison with FIG. In this optical integrated device 22, the incident surface Y side of the hologram device 18 is subjected to stray light processing by roughening processing. The optical disk device has the same configuration as the optical disk device according to the first embodiment except that the portion for performing the stray light processing is different.

According to the configuration shown in FIG. 4, the same effect as in the first embodiment can be obtained even if the incident surface side of the hologram element is subjected to stray light processing by roughening processing.

(3) Third Embodiment FIG. 5 is a sectional view showing an optical integrated device applied to an optical disk device according to a third embodiment of the present invention in comparison with FIG. In the optical integrated device 32, the incident surface Y side and the emission surface X side of the hologram element 18 are subjected to stray light processing by roughening processing. In this optical disk device,
The configuration is the same as that of the optical disk device according to the first embodiment, except that the portion for performing the stray light processing is different.

According to the structure shown in FIG. 5, since the stray light processing is performed by roughening the incident / exit surface side of the hologram element, stray light is incident on the light receiving element further more than in the first embodiment. Can be reduced.

(4) Fourth Embodiment FIG. 6 is a cross-sectional view showing an optical integrated device applied to an optical disk device according to a fourth embodiment of the present invention in comparison with FIG. In the optical integrated device 42, the incident surface Y side and the side surface Z side of the hologram element 18 are subjected to stray light processing by roughening processing. The optical disk device has the same configuration as the optical disk device according to the first embodiment except that the portion for performing the stray light processing is different.

According to the configuration shown in FIG. 6, even if stray light processing is performed by roughening the incident surface side and the side surface of the hologram element,
The same effect as in the first embodiment can be obtained.

(5) Fifth Embodiment In this embodiment, instead of the surface roughening treatment, for example, a black paint which absorbs incident light is attached to perform the stray light treatment. Note that the stray light processing can be selectively performed as needed on the incident surface, the outgoing surface, and the side surface of the hologram element 18.

As in this embodiment, the same effects as in the first embodiment can be obtained by applying a coating material that absorbs incident light and performing stray light processing instead of the surface roughening processing. . In this case, since the stray light processing can be appropriately performed on each surface of the hologram element as needed, the deterioration of the characteristics due to the stray light can be easily prevented.

(6) Sixth Embodiment In this embodiment, instead of the surface roughening treatment, for example, an anti-reflection film or the like is formed so as to improve the transmittance of incident light, or a member is polished. Treat stray light. Note that the stray light processing can be selectively performed as needed on the exit surface and side surface of the hologram element 18 excluding the entrance surface.

As in this embodiment, the same effects as in the first embodiment can be obtained by performing stray light processing so as to improve the transmittance of incident light instead of roughening processing. . In this case, since the stray light processing can be appropriately performed on each surface of the hologram element as needed, the deterioration of the characteristics due to the stray light can be easily prevented.

(7) Other Embodiments In the above embodiment, the hologram element 18
Although various stray light treatments have been described above, the present invention is not limited to this, and the cover glass may be subjected to stray light treatment.

In the above-described embodiment, the optical integrated device having the configuration in which the hologram element 18 is disposed on the cover glass has been described. However, the present invention is not limited to this, and is widely applicable to a configuration in which the cover glass is omitted. can do.

In the above embodiment, the case where the hologram element 18 is formed by injection molding of a transparent resin has been described. However, the present invention is not limited to this. Can also be widely applied.

In the above embodiment, a laser beam is set up by a right angle prism, a focus error signal is generated by a Foucault method and a spot size detection method, and a tracking error signal is generated by a three spot method and a DPP method. However, the present invention is not limited to this, and the present invention is not limited to this. For example, when a surface emitting laser diode is used, an optical integrated device according to various configurations, an optical pickup using the optical integrated device, an optical disk It can be widely applied to equipment.

In the above-described embodiment, the case where a compact disk and a DVD are accessed has been described. However, the present invention is not limited to this, and can be widely applied to a configuration for accessing various optical disks.

[0062]

As described above, according to the present invention, a hologram element constituting an optical integrated element is subjected to stray light processing for reducing the regular reflection of incident light, so that an optical pickup using the optical integrated element can be provided. Also, the incidence of stray light on the light receiving element can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an optical integrated device applied to an optical disc device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing an optical pickup to which the optical integrated device of FIG. 1 is applied.

FIG. 3 is a perspective view for explaining the operation of the optical pickup of FIG. 2;

FIG. 4 is a cross-sectional view showing an optical integrated device applied to an optical disc device according to a second embodiment of the present invention in comparison with FIG.

FIG. 5 is a cross-sectional view showing an optical integrated device applied to an optical disk device according to a third embodiment of the present invention in comparison with FIG.

FIG. 6 is a cross-sectional view showing an optical integrated device applied to an optical disk device according to a fourth embodiment of the present invention in comparison with FIG.

FIG. 7 is a sectional view showing a conventional optical pickup.

[Explanation of symbols]

1, 11,..., Optical pickup, 12, 22, 32, 42
... Optical integrated element, 9 Objective lens, 18 Hologram element, 18A, 18C Hologram

Claims (16)

[Claims] 1. An optical integrated device in which a light source for emitting a laser beam for irradiating an optical information recording medium and a light receiving element for receiving return light obtained from the optical information recording medium by the irradiation of the laser beam are integrated. A hologram element applied to the hologram element, wherein the laser beam and / or the return light is diffracted by a diffraction pattern; A hologram element which has been subjected to a stray light treatment for reducing turbulence. 2. The hologram element according to claim 1, wherein the stray light processing is a processing for roughening a surface. 3. The hologram element according to claim 1, wherein the stray light treatment is a treatment for applying a paint that absorbs incident light. 4. The hologram element according to claim 1, wherein the stray light processing is processing for improving transmittance of incident light. 5. A light source for emitting a laser beam for irradiating an optical information recording medium, a light receiving element for receiving return light obtained from the optical information recording medium by irradiating the laser beam, Placed in the light path,
An optical integrated device having a hologram element that diffracts the laser beam and or the return light by a diffraction pattern, wherein at least the diffraction pattern in the hologram element except for the diffraction pattern on the incident surface or the outgoing surface of the laser beam, An optical integrated device having been subjected to stray light processing for reducing specular reflection of incident light. 6. The optical integrated device according to claim 5, wherein the stray light processing is processing for roughening a surface. 7. The optical integrated device according to claim 5, wherein the stray light treatment is a treatment of applying a paint that absorbs incident light. 8. The optical integrated device according to claim 5, wherein said stray light processing is processing for improving transmittance of incident light. 9. A light source for emitting a laser beam for irradiating an optical information recording medium, a light receiving element for receiving return light obtained from the optical information recording medium by the irradiation of the laser beam, and a light receiving element for receiving the laser beam and the return light. An optical integrated element that is disposed in an optical path and has a hologram element that diffracts the laser beam and / or the return light according to a diffraction pattern; an objective lens that irradiates an optical information recording medium with the laser beam; An optical system that guides the return light to the optical integrated element while guiding the light beam to the objective lens, wherein the hologram element has an incident surface or an exit surface, or a side surface, of the laser beam excluding at least the diffraction pattern. Light stray light treatment for reducing the specular reflection of incident light. Up. 10. The optical pickup according to claim 9, wherein the stray light processing is processing for roughening a surface. 11. The optical pickup according to claim 9, wherein the stray light processing is a processing of applying a paint that absorbs incident light. 12. The optical pickup according to claim 9, wherein said stray light processing is processing for improving transmittance of incident light. 13. A light source for emitting a laser beam for irradiating an optical information recording medium, a light receiving element for receiving return light obtained from the optical information recording medium by irradiation of the laser beam, and a light receiving element for receiving the laser beam and the return light. An optical integrated element that is disposed in an optical path and has a hologram element that diffracts the laser beam and / or the return light according to a diffraction pattern; an objective lens that irradiates the laser beam onto an optical information recording medium; and An optical system that guides the return light to the optical integrated element while guiding the light to the objective lens; and a signal processing circuit that processes a result of receiving the return light in the light receiving element. Incident light or incident surface or exit surface or side surface of the laser beam excluding the diffraction pattern An optical information processing apparatus, wherein stray light processing for reducing specular reflection of light is performed. 14. The stray light processing is a processing for roughening a surface.
An optical information processing apparatus according to claim 1. 15. The optical information processing apparatus according to claim 13, wherein the stray light processing is a processing of applying a paint that absorbs incident light. 16. The optical information processing apparatus according to claim 13, wherein said stray light processing is processing for improving transmittance of incident light.