JPH11306585A - Composite photodetector and optical disk device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure having plural photodetecting areas and preventing currents occurring in respective photodetecting areas from affecting other photodetecting areas. SOLUTION: A photodetecting unit 16a formed with photodetecting parts A, B, C, D for a focus error signal and the photodetecting parts E, F for a tracking error in a substrate 17 and independently taking out electric signals respectively answering to incident beams from the photodetecting parts A, B, C, D and the photodetecting parts E, F is provided with the photodetecting parts S1, S2 arranged in the substrate 17 between the photodetecting parts A, B, C, D and the photodetecting parts E, F and shielding the currents leaking from the photodetecting parts E, F to the photodetecting parts A, B, C, D.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite photodetector having a plurality of photodetection areas and a CD-ROM using the same.
The present invention relates to an optical disk device capable of optically reading information using a laser disk (LD), a magneto-optical disk (MO), a digital video disk (DVD), or the like as a recording medium.
More specifically, the composite photodetector has a structure in which the current generated in each photodetection area does not affect the other photodetection areas, and the composite photodetector detects a part of the reflected light on the recording medium by a plurality of photodetectors. The present invention relates to an optical disc device that leads to a region and performs so-called tracking control and focus control based on an electric signal obtained from the light detection region.

[0002]

2. Description of the Related Art Optical disk devices are suitable for storing large-capacity programs and data, and are used in various forms. In recent years, there has been a demand for a more compact optical disk device with low manufacturing cost while reproducing optically accurate information and minimizing the number of components constituting the optical disk device.

A conventional optical disk device will be described below. The optical disk device in this example is a magneto-optical disk device using a magneto-optical disk (MO) as a recording medium. FIG. 8 is a diagram showing a configuration of a magneto-optical head device 100 which is a main part of the magneto-optical disk device. As shown in FIG. 8, the magneto-optical head device 100 includes a laser diode 1,
Collimator lens 2, first and second beam splitters 3, 10, objective lens 4, Wollaston prism 6, condensing lenses 8, 11, split photodetector 12, compound prism 15, and light serving as compound photodetector It comprises a detection unit 16 and the like. The light detection unit 16 generates an electric signal corresponding to the projected light. Also, in FIG. 8, the magneto-optical head device 100
It is arranged below.

[0004] Laser light emitted from a laser diode 1 which is a coherent light source provided in the magneto-optical head device 100 is converted into parallel light by a collimator lens 2 and is incident on a first beam splitter 3. Then, the laser beam passes through the first beam splitter 3. The laser beam transmitted through the first beam splitter 3 is
Thus, the light is focused on the magnetic film of the magneto-optical disk 5. The laser light condensed on the magneto-optical disk 5 is reflected by the magneto-optical disk 5 and re-enters the first beam splitter 3.

[0005] The reflected light incident on the first beam splitter 3 is reflected on the light detection unit 16 side and is incident on the second beam splitter 10. Then, the laser light incident on the second beam splitter 10 is separated into light transmitted through the second beam splitter 10 and light reflected on the two-divided photodetector 12 side. The light passing through the second beam splitter 10 is light passing through a servo optical system for detecting a tracking error and a focus error, and the light reflected by the second beam splitter 10 is transmitted to the magneto-optical disk 5. This is for reproducing recorded information.

The light reflected by the second beam splitter 10 toward the two-divided photodetector 12 for reproducing recorded information is condensed by the condenser lens 11 and is incident on the Wollaston prism 6 as an analyzer. Is done. And the light is
The light is split into two approximately equal parts by the Wollaston prism 6 and projected onto the two-segment photodetector 12 to form two beam spots. Then, a magneto-optical signal MO is obtained from a difference between outputs corresponding to the two beam spots. Then, the recorded information based on the magneto-optical signal MO is reproduced.

FIG. 9 is a perspective view showing a servo optical system. As shown in FIG. 9, the servo optical system includes a second beam splitter 10, a compound prism 15, and a light detection unit 1.
6 are included. The compound prism 15 has three deflecting surfaces 15a, 15b, and 15c having different inclination angles.
Are arranged side by side in the left-right direction. The left and right deflecting surfaces 15a and 15c of the composite prism 15 have a taper that deflects the light beam at different angles in the vertical direction. The central deflection surface 15b of the composite prism 15 is formed in a convex shape so as to have a predetermined curvature with respect to the optical axis of the incident light beam.

The light beam transmitted through the second beam splitter 10 and incident on the composite prism 15 having the above-described structure via the condenser lens 8 has three deflecting surfaces 15a, 15b, 15
In c, the light is divided into three, and the light is projected onto the light detection units, which are the light detection areas on the corresponding light detection units 16, to form a beam spot on each light detection unit. The light beam transmitted through the deflecting surface 15a is projected on the light detecting units A and B, the light beam transmitted through the deflecting surface 15b is projected on the light detecting units E and F, and the light beam transmitted through the deflecting surface 15c is detected by the light detecting unit. C, D
Is projected to

[0009] From the light projected on the photodetectors A, B and C, D, a focus error signal FES is obtained by the Foucault method.
Is generated. Further, a tracking error signal TES is generated from the output by the light projected on the light detection units E and F by a push-pull method. Here, for convenience of explanation, the condenser lens 8 is omitted in FIG. In the optical disk device using the magneto-optical head device 100 having the above-described configuration, the tracking error signal TES is obtained, and the laser light follows a predetermined track of the magneto-optical disk 5 so that the focus error signal FES becomes FES = 0. The magnetic head device 100 is controlled to detect the magneto-optical signal MO in a state where the laser beam is always focused on the magneto-optical disk 5. Then, the information recorded on the magneto-optical disk 5 is reproduced based on the magneto-optical signal MO.

[0010]

During normal operation of the magneto-optical head device 100 shown as a conventional example, since the focus error signal FES and the tracking error signal TES are servo-controlled, the focus error signal FES and the tracking error signal are tracked. The value of the error signal TES is almost zero.

However, during the seek operation of the track of the magneto-optical head device 100, only the focus servo is applied and the track servo is not applied, so that the value of the tracking error signal TES is not always zero. At this time,
The photodetectors A, B, for generating the focus error signal FES
Since the photodetectors C and D and the photodetectors E and F for generating the tracking error signal TES are provided on the same photodetector unit 16, the photodetectors are generated by being excited by the light beams projected on the photodetectors E and F. The current may leak from the light detection units E and F to the light detection units A, B, C and D.

Then, the leakage current is detected by the photodetectors A, B,
When added to C and D, the focus error signal FES deviates from the actual value by that amount. In this case, since the magneto-optical head device 100 changes the focus position of the laser beam so as to adjust the FES to zero based on the focus error signal FES deviated from the actual value, the actual focus position deviates from the just focus position. I will.

The present invention has been made in view of the above problems, and a first object of the present invention is to have a plurality of photodetection areas, and a current generated in each photodetection area is transmitted to another photodetection area. An object of the present invention is to provide a composite photodetector having a structure that does not affect the above. Further, a second object of the present invention is to provide the composite photodetector, wherein the tracking control and the focus control are performed by an electric signal obtained from a light detection area of the composite detector based on the reflected light on the recording medium. It is an object of the present invention to provide an optical disk device which has been described above.

[0014]

Means for Solving the Problems In order to solve the first problem, the present invention is characterized by taking the following means. According to the first aspect of the present invention, the first light detection region and the second light detection region having a photoelectric conversion function are formed in the substrate, and the incident light from the first light detection region and the second light detection region respectively. In a composite photodetector capable of independently extracting an electrical signal corresponding to the above, provided in the substrate between the first photodetection region and the second photodetection region, from one photodetection region to the other A current blocking member for blocking a current leaking to the light detection region.

Further, according to the invention described in claim 2, according to claim 1,
In the above-described composite photodetector, the current blocking member is formed in an electrode region that receives a current. In order to solve the second problem, the present invention is characterized by taking the following means.

According to the third aspect of the present invention, recording is performed based on the reflected light beam from the optical disk recording medium while controlling the light beam from the light source to irradiate the track of the optical disk recording medium on which information is recorded. Along with reproducing information, a first light detection region and a second light detection region having a photoelectric conversion function are formed in the substrate, and the first light detection region and the second light detection region are respectively converted into incident light. A composite photodetector that can independently extract the corresponding electrical signal,
A servo optical system that divides a part of the reflected light beam and guides the divided light beam to a first light detection area and a second light detection area of the composite light detector, and an electric power from the first light detection area. The light beam irradiating the optical disk recording medium is controlled to be positioned on the track based on the signal, and the light beam is focused on the optical disk recording medium surface based on the electric signal from the second light detection area. In the optical disk device that is controlled, the composite light detection unit includes:
It is provided in the substrate between the first light detection region and the second light detection region, and has a current blocking member that blocks a current leaking from one light detection region to the other light detection region. Is what you do.

Further, according to the invention described in claim 4, according to claim 3,
In the optical disc device described above, the current interrupting member in the composite photodetector is formed by an electrode region that receives a current, and the electrode region is connected to a predetermined low potential portion and received by the electrode region. A current is emitted to the predetermined low potential portion. According to a fifth aspect of the present invention, in the optical disk device according to the third aspect, the current cutoff member in the composite photodetector is formed by a third photodetection region having a photoelectric conversion function, and the reflected light is reflected by the third photodetection region. An optical system for guiding a part of the beam to the third light detection area, wherein recorded information is reproduced based on an electric signal extracted from the third light detection area. It is.

Each of the above means operates as follows. According to the first aspect of the present invention, since the current blocking member is provided in the substrate between the first light detection area and the second light detection area, one of the light detection areas is used to detect the other light. Leakage current to the area is cut off by the current cutoff member,
It is possible to provide a composite photodetector in which an erroneous electric signal is prevented from being generated from a photodetection region due to the influence of a leakage current.

According to the second aspect of the present invention, since the current interrupting member is formed in the electrode region for receiving a current, by connecting the electrode region to the outside of the composite photodetector, The leakage current flowing from the light detection region can be released to the outside. In the composite photodetector having such a configuration, for example, by connecting the electrode region to the ground, electric charges can be prevented from being accumulated in the electrode region.
Electric charges are accumulated in the electrode region, and the accumulated electric charges are prevented from adversely affecting an electric signal extracted from the first and second photodetection regions.

According to the third aspect of the present invention, the leakage current from one light detection area to the other light detection area is cut off by the current means member, so that the leakage current influences the light detection area from the light detection area. It is possible to provide an optical disk device having a composite photodetector that prevents an erroneous electric signal from being generated. Since such an optical disk device operates based on a normally generated electric signal, it is possible to accurately trace the track of the optical disk recording medium and always focus the light beam on the optical disk recording medium surface.

According to the fourth aspect of the present invention, the current interrupting member in the composite photodetector is formed by an electrode region for receiving a current, and the electrode region is connected to a predetermined low potential portion. By discharging the current received in the electrode region to the predetermined low potential portion, the electric charge is accumulated in the current interruption member, and the accumulated electric charge is extracted from the first and second light detection regions. Is prevented from being adversely affected.

Further, according to the present invention, the leakage current from one of the first light detection area and the second light detection area to the other light detection area is reduced by the third light detection area. It is possible to provide an optical disc having a compound photodetector that is prevented from generating an erroneous electric signal from the photodetection area due to the leakage current by being blocked in the area.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. In the following description of the embodiments, a magneto-optical disk device will be described as an optical disk device. FIG. 1 shows a first embodiment of the present invention, and is a view showing a configuration of a light detection unit 16a used in a magneto-optical head device which is a main part of a magneto-optical disk device.

The photodetection unit 16a is a composite photodetector and is provided in place of the photodetection unit 16 in the conventional magneto-optical head device 100 described with reference to FIGS. . The other configuration of the magneto-optical head device using the light detection unit 16a is the same as that of the magneto-optical head device 100 of the related art, and a description thereof will be omitted.

As shown in FIG. 1, the light detection unit 16a
The light detection units A, B, C, D for generating a focus error signal FES based on the light beam projected on the substrate 17 and the light detection unit E for generating a tracking error signal TES, similarly to the light detection unit 16. , F, light detection areas of the light detection units S1 and S2 are further provided. The photodetectors S1 and S2 are rectangular and provided between the photodetectors A and B and the photodetectors E and F and the photodetectors C and D and the photodetectors E and F, respectively. is there.

FIG. 2 shows the light detection unit 16a shown in FIG.
3 is a cross-sectional view as viewed from the arrow X direction. As shown in FIG. 2, in the light detection unit 16a, the light detection units A, B,
C, D, E, F, S1, and S2 are composed of a semiconductor P layer, and the substrate 17 is composed of a semiconductor N layer. The substrate 17 is supplied with a constant power supply voltage V, and the photodetectors A, B, C, D, E, and F are provided with terminals for detecting electric signals. In addition, the light detection units S1 and S2 are connected to ground, which is a predetermined low potential unit. These photodetectors S1 and S2 correspond to the electrode regions described in claims 2 and 4.

In the magneto-optical head device of the first embodiment, the light beam transmitted through the second beam splitter 10 and passed through the condenser lens 8 and the composite prism 15 is projected on the light detecting section on the light detecting unit 16a. Then, the photodetector absorbs the light energy. The electrons in the photodetection unit 16a are excited by the absorbed energy, so that the P layer where the holes gather is positively charged and the N layer where the electrons gather is negatively charged. Therefore, a voltage is generated at the junction between the P layer and the N layer. The focus error signal FES and the tracking error signal TE are generated based on the output of this voltage generated by the irradiation of each light beam from the terminal of each light detection unit.
The value of S is calculated.

This focus error signal FES is used in a magneto-optical disk drive for a focus servo mechanism which detects the vertical movement of the magneto-optical disk 5 and causes the light spot to follow the magneto-optical disk 5 so that FES = 0. Then, the tracking error signal TES is used for a tracking servo mechanism that detects the lateral swing of the track on the magneto-optical disk 5 and tracks the track. The laser beam is always focused on the magneto-optical disk 5 by the tracking servo mechanism and the focus servo mechanism.
The magneto-optical signal MO including the information recorded in is read out. Then, the magneto-optical disk device reproduces information recorded on the magneto-optical disk 5 based on the magneto-optical signal MO.

On the other hand, the light detectors S1 and S2 are not directly irradiated with the light beam, but the light detectors S1 and S2 are generated in the light detectors E and F and directed toward the light detectors A, B and C and D. And has a function of discharging the leak current flowing to the ground, which is a predetermined low voltage part. By discharging the leakage current to the ground, it is possible to prevent the leakage current from flowing into the photodetectors A, B, C, and D. Light detection unit A,
Since the leakage current does not flow into B, C, and D, the focus error signal FES is correctly calculated based on only the output of the light beams projected on the photodetectors A, B, C, and D, and the magneto-optical head device 100a is correct. The focus position can be maintained.

FIG. 3 is a diagram showing a configuration of a magneto-optical head device 100b of a magneto-optical disk device according to a second embodiment of the present invention. As shown in FIG. 3, the magneto-optical head device 100
b includes a laser diode 1, a collimator lens 2, a beam splitter 3, an objective lens 4, a Wollaston prism 6, a condenser lens 8, a compound prism 15, a light detection unit 16b, and the like. 3, the magneto-optical head device 100b is arranged below the magneto-optical disk 5.

The magneto-optical head device 100b is provided with a photo-detecting section for generating each of the magneto-optical signal MO, the tracking error signal TES, and the focus error signal FES on one photo detecting unit 16b. Reduce the size of the device by reducing the number of photodetectors and optical elements,
This is to reduce the manufacturing cost. Laser light emitted from a laser diode 1 as a coherent light source is converted into parallel light by a collimator lens 2, passes through a beam splitter 3, and is focused on a magnetic film of a magneto-optical disk 5 by an objective lens 4. . The laser light focused on the magneto-optical disk 5 is reflected by the magneto-optical disk 5 and re-enters the beam splitter 3. Then, the reflected light incident on the beam splitter 3 is transmitted to the light detection unit 1.
The light is reflected to the side 6b and enters the Wollaston prism 6, which is an analyzer.

FIG. 4 is a diagram showing a signal detection system of the magneto-optical head device 100b. The figure shows a state in which the light beam emitted from the Wollaston prism 6 is projected on the light detection unit 16b, and is a view as seen from the back side of the light detection unit 16b. As shown in FIG. 4, the reflected light incident on the Wollaston prism 6 is split into two polarized light beams and incident on the composite prism 15. The composite prism 15 is an optical element formed by arranging three deflecting surfaces 15a, 15b, and 15c having different inclination angles in parallel in the left-right direction. The left and right deflecting surfaces 15a and 15c of the composite prism 15 have a taper that deflects the light beam at different angles in the vertical direction. The central deflection surface 15b of the composite prism 15 is formed in a convex shape so as to have a predetermined curvature with respect to the optical axis of the incident light beam.

The two polarized light beams incident on the composite prism 15 having the above-described structure respectively have three deflecting surfaces 15a,
15b and 15c are spatially divided into three, and a total of six light beams are passed through the condenser lens 8 to the light detection unit 16
b is projected on the corresponding photodetector. A beam spot is formed on each light detection unit by the projected light beam. Here, for convenience of explanation, the condenser lens 8 in FIG.
Is omitted.

FIG. 5 is a diagram showing the configuration of the light detection unit 16b. As shown in FIG. 5, the light detection unit 16b
And a photodetector A, B, C, D for generating a focus error signal FES, which is an electric signal, respectively.
Photodetectors E and F for generating tracking error signal TES
And photodetectors G and H for generating a magneto-optical signal MO, and photodetectors S3 and S4.

The light detectors S3 and S4 have a rectangular shape.
They are respectively provided between the light detecting units E and F and the light detecting units A and B and the light detecting unit G, and between the light detecting units E and F and the light detecting units C and D and the light detecting unit H. . The light detection units S3, S
4 is a photodetector E, similar to the photodetectors S1 and S2 described above.
This is to prevent the leakage current generated at F from flowing into the photodetectors A, B, C, and D.

In the light detection unit 16b, the substrate 17 is formed of an N layer of semiconductor similarly to the light detection unit 16a, and the light detection units A, B, C, D, E, F, G, H, S3, and S4 are provided. It is assumed that it is composed of a semiconductor P layer. A constant power supply voltage V is applied to the substrate 17 as in the light detection unit 16a, and the light detection units A, B, C, D, E, F, G,
H is provided with a terminal for detecting an electric signal, and the light detection units S3 and S4 are connected to the ground.
These photodetectors S3 and S4 correspond to the electrode regions described in claims 2 and 4.

A focus error signal FES is obtained from the light beams projected onto the light detection units A, B, C, and D by the Foucault method, which is one of the focus error signal detection methods. A tracking error signal TES is obtained from the projected light beam by a push-pull method, which is one of the tracking error signal detection methods, and a magneto-optical signal MO is generated from the light beams projected to the light detection units G and H. can get.

On the other hand, the light detectors S3 and S4 are not directly irradiated with the light beam, but the light detectors S3 and S4 are generated in the light detectors E and F and directed toward the light detectors A, B and C and D. And has a function of discharging the leakage current flowing to the ground. By discharging the leakage current to the ground, it is possible to prevent the leakage current from flowing into the photodetectors A, B, C, and D. Since no leakage current flows into the photodetectors A, B, C, and D, the focus error signal FES is correctly calculated based on the output of only the light beams projected on the photodetectors A, B, C, and D, Head device 100
b can keep the correct focus position.

FIG. 6 is a view showing a photodetection unit 16c constituting a magneto-optical disk drive according to a third embodiment of the present invention. This light detection unit 16c is used instead of the light detection unit 16b in the above-described magneto-optical head device 100b. As shown in FIG. 6, light detection units A, B, C, and D for generating a focus error signal FES, and light detection units E for generating a tracking error signal TES are provided on a substrate 17 of the light detection unit 16c. F and
Photodetectors G and H for generating magneto-optical signal MO and semiconductor P
Photodetectors S5 and S6 composed of layers are provided.

The light detectors S5 and S6 are connected to the aforementioned S3 and S
As in the case of No. 4, the leakage current generated in the photodetectors E and F is prevented from flowing into the photodetectors A, B, C and D. Other configurations are the same as those of the light detection unit 16b.
The description is omitted. In the light detection unit 16c, the light detection units S5 and S6 are provided so as to surround the light detection units A, B, C, and D, respectively. It has a high function of preventing it from flowing into B, C, and D.

Since no leakage current flows into the photodetectors A, B, C, and D, the focus error signal FES is correctly calculated based on the output of only the light beams projected onto the photodetectors A, B, C, and D. Thus, the magneto-optical head device can maintain a correct focus position. FIG. 7 is a view showing a photodetection unit 16d constituting a magneto-optical disk drive according to a fourth embodiment of the present invention. This light detection unit 16d
Is used instead of the light detection unit 16b in the above-described magneto-optical head device 100b.

As shown in FIG. 7, the light detection unit 16d
In the figure, the photodetectors G and H for generating the magneto-optical signal MO are partially provided so as to surround the photodetectors A, B, C and D. Other configurations are the same as those of the light detection unit 16b, and the description thereof will be omitted. At the time of generating the magneto-optical signal MO, since the focus servo and the track servo are normally applied, a leakage current flows from the other photo-detecting sections into the photo-detecting sections G and H for generating the magneto-optical signal MO, and the leakage current flows. Therefore, no erroneous magneto-optical signal MO is generated. Therefore, unlike the present light detection unit 16d, a light detection unit for preventing leakage current from flowing from the light detection units E and F to the light detection units A, B, C, and D is not newly provided. The configuration may be such that leakage current is prevented from flowing in by devising the shapes of the photodetectors G and H for generating the signal MO.

Since no leakage current flows into the photodetectors A, B, C, and D, the focus error signal FES is correctly calculated based on the output of only the light beams projected on the photodetectors A, B, C, and D. Thus, the magneto-optical head device can maintain a correct focus position. In the light detection unit 16a, the substrate 17 is formed of a semiconductor P layer, and each of the light detection units A, B, C, D, E, F, G, H, S
1, S2, S3, S4, S5, and S6 may be constituted by an N layer of a semiconductor. Further, the light detection units S1, S2, S3, S4, S5, and S5 for preventing leakage current from flowing from the light detection units E and F to the light detection units A, B, C, and D.
The shapes of S6, G, and H are not limited to those shown in FIGS.

In each of the above embodiments, the composite prism 15 is disposed between the Wollaston prism 6 and the condenser lens 8, but the Wollaston prism 6 is disposed between the composite prism 15 and the condenser lens 8. A configuration may be adopted. Here, in the above embodiment, the photodetectors E and F correspond to the first photodetection area, the photodetectors A, B, C and D correspond to the second photodetection area, and the photodetectors G , H correspond to the third light detection area. Also, the light detection units 16a, 1
6b, 16c, and 16d correspond to the composite photodetector, and the photodetectors S1, S2, S3, S4, S5, and S6 correspond to the current blocking members (electrode regions).

[0045]

As described above, claims 1 and 2 are described.
According to the invention described above, it is possible to provide a composite photodetector having a plurality of photodetection regions and having a structure in which a current generated in each photodetection region does not affect other photodetection regions. According to the third to fifth aspects of the present invention, the composite light detector includes the composite light detector, and performs tracking control and focus control with an electric signal obtained from a light detection area of the composite detector based on reflected light from a recording medium. An optical disk device adapted to perform the above operation can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a light detection unit 16a used in a magneto-optical head device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the light detection unit 16a shown in FIG.

FIG. 3 is a diagram showing a configuration of a magneto-optical head device 100b.

FIG. 4 is a perspective view showing a signal detection system of the magneto-optical head device 100b.

FIG. 5 is a diagram illustrating a configuration of a light detection unit 16b.

FIG. 6 is a diagram illustrating a configuration of a light detection unit 16c.

FIG. 7 is a diagram illustrating a configuration of a light detection unit 16d.

FIG. 8 is a diagram showing a configuration of a conventional magneto-optical head device 100.

FIG. 9 is a perspective view showing a servo optical system of a conventional magneto-optical head device 100.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Laser diode 2 Collimator lens 3 First beam splitter 4 Objective lens 5 Magneto-optical disk 6 Wollaston prism 8, 11 Condensing lens 10 Second beam splitter 12 2-split photodetector 15 Composite prism 15a, 15b, 15c Deflection Surface 16, 16a, 16b, 16c, 16d Photodetection unit 17 Substrate 100, 100b Magneto-optical head device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kiyoto Matsui 4-1-1 Kamikadanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Kyoko Tadaki 4 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture No. 1-1, Fujitsu Limited (72) Inventor Kazufumi Uno 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Within Fujitsu Limited (72) Inventor Nobuyuki Kanto, Nakahara-ku, Kawasaki City, Kanagawa Prefecture 4-1-1 Odanaka Fujitsu Limited

Claims (5)

[Claims] 1. A first light detection area and a second light detection area having a photoelectric conversion action are formed in a substrate, and correspond to incident light from the first light detection area and the second light detection area, respectively. In a composite photodetector capable of independently extracting an electric signal, the composite photodetector is provided in a substrate between the first photodetection region and the second photodetection region, and one photodetection region detects the other photodetection. A composite photodetector having a current blocking member for blocking a current leaking to a region. 2. The composite photodetector according to claim 1, wherein the current interrupting member is formed in an electrode region for receiving a current. 3. A method for reproducing recorded information based on a reflected light beam from an optical disk recording medium while controlling a light beam from a light source to irradiate a track of an optical disk recording medium on which information is recorded. A first light detection region and a second light detection region having a photoelectric conversion action are formed in the substrate, and the electric signals corresponding to the incident light are respectively independent from the first light detection region and the second light detection region. And a servo optical system that divides a part of the reflected light beam and guides the divided light beam to a first light detection area and a second light detection area of the composite light detector. Then, based on the electric signal from the first light detection area, control is performed so that the light beam irradiating the optical disc recording medium is positioned on the track, and based on the electric signal from the second light detection area, the light beam is controlled. In the optical disc apparatus, the composite light detection unit is provided in a substrate between the first light detection area and the second light detection area. An optical disc device having a current blocking member for blocking a current leaking from one light detection area to another light detection area. 4. The optical disk device according to claim 3, wherein the current interrupting member in the composite photodetector is formed of an electrode region for receiving a current, and the electrode region is connected to a predetermined low potential portion. An optical disc device configured to emit a current received by the electrode region to the predetermined low potential portion. 5. The optical disc device according to claim 3, wherein the current interrupting member in the composite photodetector is formed in a third photodetection region having a photoelectric conversion function, and a part of the reflected light beam. An optical disc device having an optical system for guiding to the third light detection area, and reproducing recorded information based on an electric signal extracted from the third light detection area.