JPH10143934A - Magneto-optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a small-sized, inexpensive magneto-optical pickup device having high light utility high reliability and durability, and capable of obtaining an information signal of a sufficient S/N ratio. SOLUTION: A laser diode 3, error signal detecting photodiodes 4, 5 and an information signal detecting phtodiode 6 are provided inside a casing 1. In such a case, the inside of the casing 1 is sealed by a cover glass 7 provided with a hologram element 8, and a polarizing prism 9 containing a polarized light separation film 9a with reflectance and transmissivity different by a P polarization and an S polarization and a synthetic prism 11 integrating a Wollaston prism 10 are provided integrally on the cover glass 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a sound and image file, a document file, an external memory device for a computer, etc., and repeatedly records and reproduces information by a magneto-optical effect using a light beam. The present invention relates to a magneto-optical pickup device of a magneto-optical recording / reproducing device that can perform the above-described operations.

[0002]

2. Description of the Related Art In recent years, among optical recording / reproducing apparatuses, a magneto-optical recording / reproducing apparatus, which is one of systems capable of repeatedly recording and reproducing information, has attracted attention. In the magneto-optical pickup device, as a basic component of the magneto-optical recording / reproducing device, in particular, the miniaturization technology is regarded as the most important.

[0003] As a conventional magneto-optical pickup device which is miniaturized, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 5-205339. Hereinafter, a conventional magneto-optical pickup device will be described with reference to FIG.

FIG. 5A is a conceptual side view showing the structure of a conventional magneto-optical pickup device, and FIG. 5B is an enlarged plan view of a light receiving element portion.

In FIGS. 5 (a) and 5 (b), reference numerals 15 and 16 denote photodiodes formed on a silicon substrate 17, and three photodiodes A each divided in a direction perpendicular to the arrangement direction thereof. ~ C and D ~ F. 1
Reference numeral 8 denotes a polarizing film provided on the entire upper surface of the silicon substrate 17, which transmits only P-polarized light and reflects S-polarized light.
Reference numeral 19 denotes a prism (microprism) having a trapezoidal cross section provided above the photodiodes 15 and 16 on the polarizing film 18, and a non-polarizing film 20 having a reflectance and a transmittance of 50%, respectively, on the slope thereof. Is formed. 21
Is a quarter wave plate provided on the upper surface of the prism 19, and a total reflection film 22 is formed on the upper surface thereof. 23
Is another silicon substrate provided on the polarizing film 18,
It is arranged at a position facing the slope of the prism 19.
Numeral 24 denotes a laser diode provided on the silicon substrate 23, the polarization plane of which is 4
Emit light tilted by 5 °. 25 is a silicon substrate 23
This is another photodiode provided above, and is disposed at a position opposite to the side of the laser diode 24 toward the non-polarizing film 20. Reference numeral 26 denotes an objective lens arranged above the slope of the prism 19.

The basic operation of the conventional magneto-optical pickup device constructed as described above will be described. Light 27 emitted from the laser diode 24 is incident on the non-polarizing film 20, and only 50% of the light 27 is directed upward. Is reflected to The light 27 reflected by the non-polarizing film 20 is condensed on a magneto-optical recording medium (magneto-optical disk) 28 by an objective lens 26, and the polarization plane is rotated by a magnetic signal recorded on the magneto-optical recording medium 28. Is done. The light 27 reflected by the magneto-optical recording medium 28 passes through the objective lens 26 again and enters the non-polarizing film 20, and only 50% of the light 27 transmits through the non-polarizing film 20. The light 27 transmitted through the non-polarizing film 20 is
9 and enter the polarizing film 18. Of the light 27 incident on the polarizing film 18, only the P-polarized light component
Is transmitted to the photodiode 15, and the S-polarized light component is reflected. The S-polarized light component of the light 27 reflected by the polarizing film 18 travels in the prism 19 and
Is transmitted to the total reflection film 22, is reflected by the total reflection film 22, and passes through the quarter-wave plate 21 again. That is, the S-polarized light component of the light 27 reciprocates in the quarter-wave plate 21 and changes to P-polarized light. The light 27 reflected by the total reflection film 22 travels through the prism 19 and is incident on the polarizing film 18. Since the light 27 has been changed to P-polarized light as described above, it passes through the polarizing film 18 and The light enters the diode 16. Therefore, the magneto-optical signal RF is expressed as RF = (A + B +
C)-(D + E + F).

When the magneto-optical pickup device and the magneto-optical recording medium 28 are in focus, light 27 is focused on the total reflection film 22 as shown in FIG. , 16 have the same diameter, so that the focus error signal FE becomes FE = (A
+ C + E)-(B + D + F).

On the other hand, light 27 emitted in the direction opposite to the direction from laser diode 24 to non-polarizing film 20.
By detecting the change in the amount of light 27 incident on the photodiode 25 and received by the photodiode 25, the change in the amount of light 27 emitted from the laser diode 24 can be known.

[0009]

However, in the above-described configuration, the function of reflecting the light 27 emitted from the laser diode 24 and the function of transmitting the reflected light from the magneto-optical recording medium 28 depend on the reflectance and the reflectance. Since the transmittance is performed by the non-polarizing film 20 which does not affect the polarization direction of the light, both the reflectance and the transmittance are as low as 50%, and the expensive laser diode 24 having low light use efficiency and high radiation output is required. Not only that, the transmittance of the polarization component rotated by a minute angle due to the magnetic signal recorded on the magneto-optical recording medium 28, that is, the transmittance of the magneto-optical signal component is similarly poor, so that a sufficient SN ratio of the magneto-optical signal is obtained. Cannot be obtained, and good performance as a magneto-optical pickup device cannot be secured.

Further, an expensive quarter-wave plate 21 and another silicon substrate 23 for arranging the laser diode 24 and the photodiode 25 are required, so that the number of parts as the magneto-optical pickup device is large, and the cost is low. Is difficult.

The present invention solves the above-mentioned problems of the conventional magneto-optical pickup device, and provides an inexpensive and small-sized magneto-optical recording and reproducing device which has good light use efficiency, a good SN ratio, and is inexpensive. The purpose is to provide.

[0012]

In order to achieve the above object, a magneto-optical pickup device according to the present invention comprises a light emitting element,
A light-receiving element for detecting an information signal and a light-receiving element for detecting an error signal, a light-collecting element that irradiates light emitted from the light-emitting element onto the information recording medium, and is provided in an optical path between the light-emitting element and the light-collecting element; A prism having a transmission / reflection surface that guides light emitted from the light-emitting element to the light-collecting element, transmits part of the light reflected by the information recording medium, and transmits the light again through the light-collecting element, and a part of the prism. A compound prism integrally provided with an analyzer that splits light reflected (transmitted) by the transmission / reflection surface into a plurality of lights having at least two orthogonal polarization components and guides the light to an information signal detecting light receiving element; A direction different from the direction in which the light emitted from the element is guided to the compound prism, and the light reflected by the information recording medium, transmitted again through the light-collecting element, and transmitted (reflected) through the transmission / reflection surface of the compound prism, returns to the light-emitting element. What A light branching element for branching and leading to an error signal detecting light receiving element; a light emitting element, an information signal detecting light receiving element and an error signal detecting light receiving element are integrally provided inside the housing; An optical branching element is mounted so as to seal the inside of the housing, and a composite prism is integrally formed on the upper surface of the optical branching element.

In this way, an inexpensive and compact magneto-optical pickup device for a magneto-optical recording and reproducing device can be obtained. Also P
By using a polarization separation film having different reflectance and transmittance between the polarized light and the S-polarized light, the light use efficiency is high and a sufficient SN ratio of the information signal can be secured. In addition, an expensive wave plate is not required, and cost can be reduced with one silicon substrate. In addition, the monitor photodiode detects the change in the radiation intensity of the light emitted from the laser diode, and the change in the amount of light emitted by the laser diode is small, resulting in good recording / reproduction performance of the magneto-optical pickup device. Can be obtained.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a conceptual side view showing a configuration of a magneto-optical pickup device according to a first embodiment of the present invention, and FIG. 2 is a light emitting element and an information signal detecting device according to the first embodiment. It is a top view of a light receiving element and a light receiving element part for error signal detection.

1 and 2, reference numeral 1 denotes a housing made of, for example, an epoxy resin or a metal such as iron or copper, and a silicon substrate 2 is provided inside the housing.
On the silicon substrate 2, a laser diode 3 that emits, for example, P-polarized light as a light emitting element, photodiodes 4 and 5 for detecting an error signal, and a photodiode and a diode 6 for detecting an information signal as a light receiving element are provided. . The laser diode 3 has, for example, a concave portion having a substantially 45-degree slope by etching or the like in a part of the silicon substrate 2, and a light-emitting chip is mounted therein, so that light emitted from the light-emitting chip hits the 45-degree slope. , And emits P-polarized light, for example. The error signal detecting photodiodes 4 and 5 are
As shown in FIG. 2, the information signal detecting photodiode 6 is composed of six divided portions 4a to 4f and 5a to 5f, respectively. It consists of portions 6a and 6b which are divided substantially in the same direction. Reference numeral 7 denotes a cover glass, which is made of, for example, a resin such as polycarbonate or optical glass, and is provided on a part of the surface opposite to the surface facing the laser diode 3, in a region through which radiated light from the laser diode 3 passes. A hologram element 8 as a light branching element is provided by etching or molding. The hologram element 8 has a lens effect such that the focal positions of the ± 1st-order diffracted lights diffracted at an angle of substantially 5 to 20 degrees are different. The cover glass 7 is positioned so that the ± 1st-order diffracted lights diffracted by the hologram element 8 are guided to the error signal detecting photodiodes 4 and 5, respectively, and is adhered so as to seal the inside of the housing 1. , Is fixed to the upper surface of the housing 1. Reference numeral 9 denotes a polarizing prism formed by joining optical glass having a substantially triangular cross section and optical glass having a substantially parallelogram cross section by optical bonding. For example, a polarization separation film 9a is provided on the bonding surface so that the transmittance of P-polarized light is substantially 70%, the reflectance is substantially 30%, and the reflectance of S-polarized light is substantially 100%. I have. The inclined surface 9b substantially parallel to the bonding surface on which the polarization separation film 9a is provided is inclined toward the inside of the housing 1, and substantially reflects the light reflected on the bonding surface on which the polarization separation film 9a is provided. It is configured to bend only once. 10
For example, two members of, for example, quartz or lithium niobate having a substantially triangular cross section have optical axes orthogonal to each other, and their optical axes are substantially the same as the polarization direction of the light reflected by the inclined surface 9 b of the polarizing prism 9. A Wollaston prism as an analyzer joined by optical bonding so as to form an angle of 45 degrees. The Wollaston prism 10 separates the light reflected by the inclined surface 9b of the polarizing prism 9 into two lights having polarization components orthogonal to each other and emits the light, and guides the light to the portions 6a and 6b of the information signal detecting photodiode 6. It is configured as follows. The polarizing prism 9 and the Wollaston prism 10 are integrated by optical bonding to form the composite prism 1.
1. In the composite prism 11, light emitted from the laser diode 3 and transmitted through the hologram element 8 on the cover glass 7 by bonding or the like on the cover glass 7 is incident on the bonding surface of the polarizing prism 9 on which the polarization separation film 29 is provided. Fixed in position. An objective lens 12 is provided above the polarizing prism 9 and is made of, for example, a resin such as acrylic or polycarbonate or an optical glass as a light-collecting element. The transmitted light is focused on the magneto-optical disk 13 and
It has the function of transmitting the light reflected by the magneto-optical disk 13 again and returning it to the polarizing prism 9.

The basic operation of the magneto-optical pickup device according to the first embodiment configured as described above will be described. The P-polarized light emitted from the laser diode 3 passes through the hologram element 8 on the cover glass 7 and enters the polarizing prism 9. In the polarization separating film 9a provided on the bonding surface of the polarizing prism 9, substantially 70% of the P-polarized light is transmitted and emitted from the polarizing prism 9, and the objective lens 12
Is condensed on the magneto-optical disk 13. On the magneto-optical disk 13, the direction of polarization of the light is substantially rotated by about 0.5 degrees by the recorded magnetic signal, and a slight S-polarized component as a magneto-optical signal is obtained and the light is reflected. The reflected light passes through the objective lens 13 again, enters the polarizing prism 9, and returns to the polarization separation film 9a. The polarization splitting film 9a transmits substantially 70% of the P-polarized light, and reflects substantially 30% of the P-polarized light and substantially 100% of the S-polarized light component (magneto-optical signal). Of these, substantially 30% of the P-polarized light and S-polarized light components (magneto-optical signals) reflected by the polarization separation film 9a are reflected by the slope 9b and bend the optical path by substantially 90 degrees to exit the polarizing prism 9. Incident on the Wollaston prism 10, is separated into two lights having polarization components orthogonal to each other, exits the Wollaston prism 10, and is guided to the portions 6a and 6b of the information signal detecting photodiode 6. Accordingly, the portions 6a, 6a of the information signal detecting photodiode 6
If the signal obtained in b is denoted by the same reference,

[0017]

## EQU1 ## An information signal RF is obtained by differential detection of RF = 6a-6b.

On the other hand, substantially 7
The 0% P-polarized light exits the polarizing prism 9 and enters the hologram element 8 of the cover glass 7. Here, the light is diffracted substantially at a diffraction angle of 5 to 20 degrees. For example, the + 1st-order diffracted light enters the error signal detecting photodiode 4, and
The first-order diffracted light enters the error signal detecting photodiode 5. At this time, due to the lens effect of the hologram element 8, for example, the + 1st-order diffracted light is focused at a position closer to the cover glass 7 than the photodiode 4 for detecting an error signal.
The -1st-order diffracted light is focused at a position farther from the error signal detecting photodiode 5. Therefore, when the magneto-optical pickup device and the magneto-optical disk 13 are in focus, the hologram element 8 of the cover glass 7 is so adjusted that the diameters of the light spots on the error signal detecting photodiodes 4 and 5 are the same. When the distance between the magneto-optical pickup device and the magneto-optical disk 13 changes, the light spot on the error signal detecting photodiodes 4 and 5 is set. Vary in size to different sizes. Therefore,

[0019]

FE = ｛(4a + 4c + 4d + 4f) + (5b
+ 5e)｝-｛(4b + 4e) + (5a + 5c + 5d +
5f) The focus error signal FE is obtained by the differential detection of｝.

The error signal detecting photodiode 4
Dividing line 4g separating portions 4a-4c and 4d-4f, and portions 5a-5c of photodiode 5 for error signal detection
A dividing line 5g for dividing the optical disk 1
3 is arranged so that the directions of the information tracks are parallel to each other, and when there is no displacement of the information tracks of the magneto-optical disk 13 with respect to the magneto-optical pickup apparatus, the error signal detecting photodiode 4 , 5
By setting the positional relationship between the hologram element 8 of the cover glass 7 and the error signal detecting photodiodes 4 and 5 so that the upper light spot is on each of the division lines 4g and 5g, the magneto-optical pickup device is provided. When the information track on the magneto-optical disk 13 is misaligned, the spots on the error signal detecting photodiodes 4 and 5 are directed in the direction orthogonal to the information tracks on the magneto-optical disk 13, that is, with the dividing lines 4g and 5g. They move in opposite directions in orthogonal directions. Therefore,

[0021]

## EQU3 ## TE = ｛(4a + 4b + 4c) + (5a + 5b)
+ 5c)｝-｛(4d + 4e + 4f) + (5d + 5e +
5f) The tracking error signal TE is obtained by the differential detection of｝.

As described above, according to the magneto-optical pickup device of the first embodiment, the laser diode 3, the error signal detecting photodiodes 4, 5 and the information signal detecting pho and diode are provided inside the housing 1. By disposing the silicon substrate 2 provided with 6, directly forming the cover glass 7 on the housing 1, and integrally forming the composite prism 11 on the cover glass 7, the size of the magneto-optical pickup device can be reduced. be able to. Further, by using the polarization separation film 9a having different reflectance and transmittance between the P-polarized light and the S-polarized light, the light use efficiency is high and a sufficient SN ratio of the information signal can be secured.

Further, since an expensive wavelength plate is not required and only one silicon substrate 2 is used, the cost can be reduced.

Further, by adopting a structure in which the inside of the housing 1 is sealed with the cover glass 7, the reliability performance against temperature and humidity and the durability can be improved. (Second Embodiment) Next, a second embodiment of the magneto-optical pickup device of the present invention will be described with reference to FIG. 3 differs from FIG. 1 in that the light emitted from the laser diode 3 is S-polarized light, and the transmission / reflection characteristic of the polarization separation film 9a of the polarizing prism 9 is, for example, the reflectance of S-polarized light is substantially 70%. And the transmittance of P-polarized light is substantially 100%, and the light emitted from the laser diode 3 and reflected by the polarization separation film 9a of the polarizing prism 9 is guided to the objective lens 12. That is, Since the light irradiating the magneto-optical disk 13 is S-polarized, the magneto-optical signal becomes a P-polarized component. Therefore, of the light reflected by the magneto-optical disk 13 and transmitted through the objective lens 12 again, the polarization separation film of the polarizing prism 9 is formed. Substantially 30% of the S-polarized light and the P-polarized light component (magneto-optical signal) transmitted through 9a are reflected by the slope 9b and guided to the Wollaston prism 10. On the other hand, substantially 70% of the S-polarized light reflected by the polarization separation film 9a is guided to the hologram element 8 of the cover glass 7, and
Hereinafter, by the same operation as that of the first embodiment, each signal of the information signal RF, the focus error signal FE, and the tracking error signal TE is obtained. Further, while reducing the size and cost of the magneto-optical pickup device, The light use efficiency can be increased, and a sufficient SN ratio of the information signal can be secured. (Third Embodiment) Next, a third embodiment of the magneto-optical pickup device of the present invention will be described with reference to FIG. Note that the components denoted by the same reference numerals as those in the first embodiment are substantially the same, and the description thereof will be omitted. The basic operation of the magneto-optical pickup device is the same as that of the first embodiment, and the description thereof is omitted.

As is clear from FIG. 4, the third embodiment differs from the first embodiment in that the thickness of the cover glass 7 is increased and the surface of the cover glass 7 facing the laser diode 3 is changed. 3 and silicon substrate 2
In the vicinity of the laser diode 3 above, a monitoring photodiode 14 for receiving light newly emitted from the laser diode 3 and reflected on the surface of the cover glass 7 facing the laser diode 3 is provided. The light radiated from the laser diode 3 and reflected by the surface of the cover glass 7 facing the laser diode 3 reaches only the monitor photodiode 14 and includes the error signal detection photodiodes 4 and 5 and the information signal detection photo. It is configured not to reach the diode 6.

Generally, the radiation intensity of the light radiated from the laser diode 3 changes due to environmental changes such as temperature and humidity. On the other hand, since the reflectance of the surface of the cover glass 7 facing the laser diode 3 is substantially constant,
If the radiation intensity of the light emitted from the laser diode 3 changes, the light reflected on the surface of the cover glass 7 facing the laser diode 3 also changes in intensity accordingly. Therefore, by monitoring the change in the intensity of light emitted from the laser diode 3 by the monitoring photodiode 14 and reflected by the surface of the cover glass 7 facing the laser diode 3, the emission intensity of the light emitted from the laser diode 3 is monitored. Can be detected. Further, by controlling the amount of radiation of the laser diode 3 so as to keep the output of the monitoring photodiode 14 constant, recording / reproduction of the magneto-optical pickup device caused by a change in the radiation intensity of the light radiated from the laser diode 3 is performed. Performance degradation can be prevented.

As described above, according to the magneto-optical pickup of the third embodiment, as in the case of the first embodiment, light utilization is achieved while reducing the size and cost of the magneto-optical pickup device. Not only can the efficiency be increased and a sufficient SN ratio of the information signal can be ensured, but also the change in the radiation intensity of the light radiated from the laser diode 3 can be detected by the monitoring photodiode 14, so that the laser diode 3 The change in the light amount is small due to the control of the amount of emitted light, so that a good recording / reproducing performance of the magneto-optical pickup device resulting therefrom can be obtained.

The hologram element 8 is formed of a cover glass 7
May be provided in a region of the surface facing the laser diode 3 through which light emitted from the laser diode 3 passes.

The polarizing prism 9 is formed by joining optical glass having a substantially triangular cross section and optical glass having a substantially parallelogram cross section by optical bonding. You may comprise three and join.

When these three optical glasses are bonded, instead of attaching the Wollaston prism 10 to the lower surface of the polarizing prism 9 as shown in FIG. 1, a portion corresponding to the parallelogram in FIG. 1 is formed. The composite prism 11 may be configured by sandwiching the Wollaston prism 10 between the triangular optical glasses.

Alternatively, instead of attaching the Wollaston prism 10 to the lower surface of the polarizing prism 9 as shown in FIG. 1, the inclined surface 9b of the parallelogram optical glass shown in FIG. The prism 10 may be attached. In that case, a reflection type thing is used for the Wollaston prism 10. In this case, the light reflected by the polarization separation film 9a, which is a transmission / reflection surface, passes through the slope 9b, is reflected by the Wollaston prism 10, and changes the direction by 90 degrees.
It goes to the information signal detecting photodiode 6. At the time of the reflection, the light branches.

The analyzer may be, for example, a plate-like polarization diffraction element (polarization hologram) made of lithium niobate.

The analyzer may be a reflection type polarization diffraction element, which is joined to the inclined surface 9b of the polarization prism 9.

[0034]

As is apparent from the above description,
According to the magneto-optical pickup device of the present invention, the size of the magneto-optical pickup device can be reduced.

[Brief description of the drawings]

FIG. 1 is a conceptual side view showing a configuration of a magneto-optical pickup device according to a first embodiment of the present invention.

FIG. 2 is a plan view of a light-emitting element and a light-receiving element in the embodiment.

FIG. 3 is a conceptual side view showing a configuration of a magneto-optical pickup device according to a second embodiment of the present invention.

FIG. 4 is a conceptual side view showing a configuration of a magneto-optical pickup device according to a third embodiment of the present invention.

5A is a schematic side view showing a configuration of a conventional magneto-optical pickup device, and FIG. 5B is an enlarged plan view of a light receiving element portion.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 housing 2 silicon substrate 3 laser diode 4, 5 error signal detecting photodiode 6 information signal detecting photodiode 7 cover glass 8 hologram element 9 polarizing prism 9 a polarizing separation film 9 b slope 10 Wollaston prism 11 compound prism 12 objective lens 13 Magneto-optical disk 14 Photodiode for monitor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayuki Nagata 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (9)

[Claims] A light-emitting element; a light-receiving element for detecting an information signal; a light-receiving element for detecting an error signal; a light-collecting element that irradiates light emitted from the light-emitting element onto an information recording medium; Provided in the optical path between the light collection elements,
A prism having a transmission / reflection surface that guides light emitted from the light emitting element to the light collecting element, and transmits part of light reflected by the information recording medium and transmitted through the light collecting element again and partially reflects the light. And an analyzer in which light reflected by the transmission / reflection surface of the prism is split into a plurality of lights having at least two orthogonal polarization components and guided to the information signal detecting light receiving element. A prism, and guides the light emitted from the light emitting element to the composite prism, and reflects the light reflected by the information recording medium, transmitted again through the light-collecting element, and transmitted through the transmitting / reflecting surface of the composite prism to the light-emitting element. A light branching element for branching in a direction different from the returning direction to the light receiving element for error signal detection, wherein the light emitting element, the information signal detecting light receiving element and the light A light receiving element for signal detection is integrally provided, and the light splitting element is sealed on the upper surface of the housing so as to seal the inside of the housing, and the composite prism is further integrated on the upper surface of the light splitting element. The configured magneto-optical pickup device. 2. A light-emitting element, a light-receiving element for detecting an information signal, a light-receiving element for detecting an error signal, a light-collecting element for irradiating light emitted from the light-emitting element onto an information recording medium, and the light-emitting element. Provided in the optical path between the light collection elements,
A prism having a transmission / reflection surface that guides light emitted from the light emitting element to the light collecting element, and transmits part of light reflected by the information recording medium and transmitted through the light collecting element again and partially reflects the light. And an analyzer in which light transmitted through the transmission / reflection surface of the prism is split into a plurality of lights having at least two orthogonal polarization components and guided to the information signal detecting light-receiving element. A prism, and guides the light emitted from the light emitting element to the composite prism, and reflects the light reflected by the information recording medium, transmitted again through the light-collecting element, and reflected by the transmitting / reflecting surface of the composite prism to the light emitting element. A light branching element for branching in a direction different from the returning direction to the light receiving element for error signal detection, wherein the light emitting element, the information signal detecting light receiving element and the light A light receiving element for signal detection is integrally provided, and the light splitting element is sealed on the upper surface of the housing so as to seal the inside of the housing, and the composite prism is further integrated on the upper surface of the light splitting element. The configured magneto-optical pickup device. 3. The magneto-optical pickup device according to claim 1, wherein the light emitting element is a surface emitting laser, and the light receiving element for detecting an information signal and the light receiving element for detecting an error signal are integrally formed on the same substrate. . 4. The magneto-optical pickup device according to claim 1, wherein the transmission / reflection surface of the prism is a polarization separation surface having different reflectance and transmittance between P-polarized light and S-polarized light. 5. The magneto-optical pickup device according to claim 1, wherein the light splitting element is a hologram element having a lens effect. 6. The analyzer is a Wollaston prism,
3. The magneto-optical pickup device according to claim 1, wherein the magneto-optical pickup device is provided on a surface of the prism facing the light emitting element and the signal detecting light receiving element. 7. The magneto-optical pickup device according to claim 1, wherein the analyzer is provided in a plane substantially perpendicular to a surface of the prism facing the light emitting element and the signal detecting light receiving element. 8. The magneto-optical pickup device according to claim 1, wherein the analyzer is provided substantially parallel to the transmission / reflection surface of the prism. 9. A monitoring light receiving element for receiving light radiated from the light emitting element and reflected on a surface of the light splitting element facing the light emitting element, the light receiving element for detecting an information signal and the light receiving element for detecting an error signal. 3. The magneto-optical pickup device according to claim 1, wherein said magneto-optical pickup device is provided on substantially the same plane as said.