JP3780845B2 - Opto-electronic module and optical head or optical disk apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical head for recording information on or reproducing information from an optical information medium such as an optical disk, and an optical information medium recording / reproducing apparatus using the optical head.
[0002]
[Prior art]
2. Description of the Related Art In recent years, optical information recording / reproducing apparatuses such as optical disk apparatuses have been used for various purposes and are mounted on various devices. For the mounting, optical heads used therefor can be made thin and easy to manufacture. It is also important. In order to realize a thin optical head, for example, in Japanese Patent Laid-Open No. 06-076340, a light emitting / receiving unit in which a semiconductor laser, a photodetector, an electronic circuit, and the like are housed in one package, and an optical head using the same are disclosed. It is shown. In the light emitting / receiving unit shown in FIG. 1 of the publication, a semiconductor laser element is disposed in a recess formed in a silicon substrate, and the laser beam is reflected by the inclined surface of the end of the recess and emitted almost perpendicularly to the silicon substrate surface. Further, a photodetection element and an electronic circuit are formed on the surface of the silicon substrate, and a laser beam reflected by the optical disk is received by the photodetection element, and an output of the photodetection element is converted into an electric signal by the electronic circuit. The light-emitting / receiving unit has a rectangular flat package type ceramic substrate, and leads to supply power to the semiconductor laser element, photodetection element, and electronic circuit on the silicon substrate, and to take out the output signal of the electronic circuit. The lines are on both sides of the package in the longitudinal direction. Since there is no lead wire in the short direction of the package, as shown in FIG. 2 of the same publication, when the light emitting / receiving unit is attached to the optical head so that the short direction of the package is the thickness direction of the optical head, the optical head is thinned. can do. As described above, a module in which a plurality of elements are housed in a package having a substantially rectangular shape that is long in one direction and having lead wires or lead terminals on both sides in the longitudinal direction is suitable for thinning an optical head and an optical disk device. Yes.
[0003]
However, it is difficult to obtain sufficient performance with a module in which a photodetecting element and an electronic circuit are formed on the same silicon substrate as in the above example. When an electronic circuit is formed on a silicon substrate, the depth of the pn junction region on the silicon surface is about 1 μm, and the shallower the speed, the higher the speed. On the other hand, in order to obtain sufficient light receiving sensitivity of the photodetecting element, the depth of the pn junction region on the silicon surface needs to be several μm to 10 μm, and the deeper the light receiving sensitivity becomes. Therefore, when the photodetecting element and the electronic circuit are formed on the surface of the silicon substrate as in the conventional example described above, it is difficult to form a high-speed electronic circuit with a high light receiving sensitivity of the photodetecting element.
[0004]
Further, since the output current of the photodetecting element is on the order of μA, the electronic circuit needs to amplify a minute current with low noise. On the other hand, the driving current of the semiconductor laser is about several tens mA to 100 mA, and noise is likely to be generated in the vicinity due to the large driving current of the semiconductor laser. Therefore, when an electronic circuit such as an amplifier and a laser driving circuit are mixed on the same semiconductor substrate, noise is easily mixed into the electronic circuit.
[0005]
Therefore, as one method for solving the above problems, the electronic circuit and the light detection element are manufactured on separate wafers, and the electronic circuit board and the light detection element substrate cut out from each wafer are arranged in a package. It is conceivable to connect by wire bonding or the like. According to this method, a high-speed electronic circuit can be realized by using a silicon wafer having a shallow pn junction region, and a light detection element having high light receiving sensitivity can be realized by using a silicon wafer having a deep pn junction region. .
[0006]
[Problems to be solved by the invention]
However, in the above-described solution, there are cases where the optical head and the optical disk apparatus cannot be sufficiently thinned.
[0007]
As an example, in the light-emitting / receiving unit disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 06-076340, the electronic circuit has the simplest six preamplifier configurations that simply convert the outputs of the six photodetecting elements into electric signals. Think about the case. After the electronic circuit and the photodetecting element are manufactured on separate silicon wafers, the electronic circuit board and the photodetecting element substrate are arranged side by side in the longitudinal direction in the package. The outputs of the six light receiving elements are connected to the electronic circuit board from the light detecting element substrate by a metal wire by a wire bonding apparatus. The connection between the outside of the package and the light receiving element substrate on which the semiconductor laser element is mounted is the three power lines of the laser power line, the light detecting element power line, and the ground line. Good. On the other hand, the connection between the outside of the package and the electronic circuit board requires 6 preamplifier output signal lines, 8 power supply lines for the electronic circuit, and 8 ground lines, so there are 8 lead wires on the electronic circuit board side of the package. It becomes. Considering the work of soldering lead wires to flexible cables, etc., there is a limit to the minimum distance between lead wires, so if the number of lead wires on one side is large, the width of the package becomes large and the optical head and optical disk device are thin. Cannot be achieved sufficiently.
[0008]
An object of the present invention is to provide a light receiving element, an electronic circuit that performs processing such as amplification of an electric signal output from the light receiving element, a laser light source, a laser control circuit for controlling the light emission amount of the laser light source, and the like in one package. The optical-electronic module housed in the optical head and the optical head or optical disk apparatus using the same are high-speed and high-speed electronic circuits of the light detection element, which can reduce noise, and are thin in the optical head and optical disk apparatus. It is an object of the present invention to provide an opto-electronic module suitable for manufacture, and an optical head or an optical disc apparatus using the same.
[0009]
[Means for Solving the Problems]
  Above purposeCan be achieved by the invention described in the claims..
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
[0022]
FIG. 1 shows a basic configuration of an optical disc apparatus 1 using the present invention, in which (a) on the upper left side is a top view seen from above, and (b) on the upper right side is seen from the direction of arrow B in (a). The side view, (c) in the lower stage is a side view seen from the direction of arrow C in (a), and the parts denoted by the same numbers indicate the same parts. Reference numeral 2 denotes an optical disk, 3 denotes a motor, which is fixed to the optical disk apparatus 1 and rotates the optical disk 2 via a rotating shaft 4. An optical head 5 can be moved in the radial direction of the optical disk 2 on the rail 7 by an access mechanism 6 constituted by a voice coil motor and a pulley. In the optical head 5, a laser module 8, a collimating lens 9, a mirror prism 10, and a lens actuator 11 are incorporated. A semiconductor laser chip 13 that emits a laser beam 12 is incorporated in the laser module 8. The lens actuator 11 is provided with a composite element 14 and a focus lens 15 in which a quarter-wave plate and a polarization diffraction grating are combined.
[0023]
The upper part (a) of FIG. 2 shows the structure of the laser module 8, and the lower part (b) is a sectional view. Reference numeral 21 denotes a package formed of a material having good thermal conductivity such as aluminum nitride, and a plurality of lead wires 22 are penetrated to transmit an electric signal. The package 21 is sealed with a light transmissive glass plate 23. Inside the package 21 is a light receiving element substrate 24 such as silicon and an electronic circuit substrate 28. A recess 25 is formed in the substantially central portion of the light receiving element substrate 24 by etching or the like, and the inclined surface of the recess 25 is a mirror surface 25 'having an angle of about 45 degrees. The semiconductor laser chip 13 is mounted in the recess 25. Four light receiving elements 26 are formed on the upper side of the recess 25, and four sets of two-divided light receiving elements 27 are formed on the lower side. Six amplifiers 29 are formed on the electronic circuit board 28.
[0024]
In FIG. 2 (a), for the purpose of explanation, the ten lead wires 22 are provided on the left side from the upper side to the lower side 22-1, 22-2,. Serial numbers 22-6, 22-7,..., 22-10 are assigned. The pads on the right side of the light receiving element substrate 24 are assigned serial numbers 30-1, 30-2,..., 30-4 from the top to the bottom. Serial numbers 31-1, 31-2, ..., 31-9 are assigned downward. Further, the pads on the right side of the electronic circuit board 28 are given serial numbers 32-1, 32-2,..., 32-9 from the top to the bottom, and the pads on the left side of the electronic circuit board 28 are assigned from the top. Numbering serial numbers 33-1, 33-2, ..., 33-5 downward. These pads and lead wires are connected with metal wires as shown in FIG. 2A using a wire bonding apparatus. The lead wire 22-6 on the right side of the package 21 is an electrically common ground line for the light receiving element substrate 24 and the electronic circuit board 28, and is connected to the pad 30-1 on the right side of the light receiving element substrate 24. The pad 31-1 is also connected to the pad 32-1 on the right side of the electronic circuit board 28. The applied voltage required to operate the light receiving elements 26 and 27 on the light receiving element substrate 24 is supplied from the right lead wire 22-7 of the package 21 through the right pad 30-2 of the light receiving element substrate 24. Electric power necessary for causing the semiconductor laser chip 13 disposed on the light receiving element substrate 24 to emit light is supplied to the semiconductor laser chip 13 from the lead wire 22-8 on the right side of the package 21. The electric power required to operate the amplifier 29 of the electronic circuit board 28 is supplied from the left lead wire 22-5 of the package 21 through the left pad 33-5 of the electronic circuit board 28.
[0025]
When an electrical signal is supplied to the semiconductor laser chip 13 from the lead wire 22-8 on the right side of the package 21, the semiconductor laser chip 13 emits the laser beam 12 in the left direction on the paper surface. The laser beam 12 emitted from the semiconductor laser chip 13 in the left direction in the drawing is reflected by the mirror surface 25 ′ in FIG. 2B, passes through the glass plate 23, and is emitted from the laser module 8. In FIG. 1C, the laser beam 12 emitted from the laser module 8 becomes a parallel light beam by the collimating lens 9, is reflected by the mirror prism 10, and enters the composite element 14 and the focus lens 15 incorporated in the lens actuator 11. . In this embodiment, when the laser beam 12 emitted from the semiconductor laser chip 13 is incident on a composite element 14 having a polarizing quadrant diffraction grating and a quarter-wave plate, for example, the laser beam 12 is incident and polarized as an ordinary ray. The diffractive grating part is transmitted without being diffracted, and becomes circularly polarized light by the quarter wave plate of the composite element 7. The laser beam 12 reflected by the optical disk passes through the quarter-wave plate of the composite element 7 again, and becomes an extraordinary ray, and is diffracted by the polarizing quadrant diffraction grating. FIG. 3 shows an example of a diffraction grating pattern of a four-part diffraction grating in the composite element 14, which is divided into four regions by boundary lines 37 and 38. A circle 12 represents a laser beam reflected by the optical disk, and is divided into four + 1st order diffracted lights and four −1st order diffracted lights by a four-part diffraction grating. The diffraction gratings in the four regions have different grating groove directions, but the intervals between the grating grooves are equal. Therefore, the eight ± 1st-order diffracted lights have different diffraction directions but equal diffraction angles. The eight diffracted lights are respectively collected by the collimator lens 9 and focused as eight spots on the surface of the light receiving element substrate 24 in the laser module 8, and are collected as four light receiving elements 26 and four sets of two-divided light receiving elements 27. Is received.
[0026]
The detection signals of the four light receiving elements 26 are sent from the pads 31-2, 31-3, 31-4, 31-5 on the left side of the light receiving element substrate 24 to the pads 32-2, 32 on the right side of the electronic circuit board 28. -3, 32-4, and 32-5, each of which is amplified by four amplifiers 29 from the top of the electronic circuit board 28 and converted into an electrical signal, and the pad 33-1 on the left side of the electronic circuit board 28 , 33-2, 33-3, and 33-4 through the lead wires 22-1, 22-2, 22-3, and 22-4 on the left side of the package 21. From the detection signals of the four light receiving elements 26, a track deviation detection signal and an information reproduction signal can be obtained. The two-divided light receiving element 27 is a light detecting element for obtaining a defocus detection signal, and one two-divided light receiving element 27 is composed of two elongated light detecting elements facing each other. As the defocus detection method, a knife edge method (Fucault method) is used, and a defocus detection signal can be obtained by calculating the difference between the output signals of two light receiving elements in each group. In this embodiment, four sets of two-divided light receiving elements 27 are connected with conductive thin films such as aluminum as shown in the figure, and detection signals having the same polarity are combined. Two signals for detecting defocus are supplied from pads 31-6 and 31-7 to pads 32-6 and 32-7 on the right side of the electronic circuit board 28, and two signals are respectively provided on the lower side of the electronic circuit board 28. Are amplified by the amplifier 29 and converted into an electric signal. Two signals for defocus detection are connected to pads 32-8 and 32-9 on the right side of the electronic circuit board 28, and from there, pads 31-8 and 31-9 on the left side of the light receiving element substrate 24. Are connected to pads 30-3 and 30-4 on the right side of the light receiving element substrate 24 through conductive thin films 34 and 35 such as aluminum, and lead wires 22-9 and 22-10 on the right side of the package 21 are connected. Output through.
[0027]
FIG. 4 is a block diagram of a signal calculation circuit for obtaining a defocus detection signal, a track shift detection signal, and an information reproduction signal. Two signals for defocus detection output from the lead wires 22-9 and 22-10 on the right side of the package 21 shown in FIG. 2A are connected to the a terminal and the b terminal shown in FIG. 41-1 is a differential circuit for subtracting the output signals from the a terminal and b terminal, and outputs a defocus detection signal 42-1. Reference numeral 41-2 denotes an adding circuit for adding output signals from the a terminal and the b terminal, and outputs a sum signal 42-2 used for stabilizing the detection sensitivity of the defocus detection signal. A signal obtained by dividing the defocus detection signal 42-1 by the sum signal 42-2 becomes a stable defocus detection signal that does not depend on the reflectance change of the optical disk or the output fluctuation of the semiconductor laser. The four signals output from the left lead wires 22-1, 22-2, 22-3, and 22-4 of the package 21 shown in FIG. 2A are the c terminal, d terminal, and e shown in FIG. Terminal and f terminal. Reference numeral 43-1 denotes an adding circuit for adding output signals from the c terminal and the d terminal, and 43-2 denotes an adding circuit for adding output signals from the e terminal and the f terminal. 43-3 is a differential circuit for subtracting the output signal of the adder circuit 43-1 and the output signal of the adder circuit 43-2, and a push-pull type track deviation detection signal when an optical disc having a guide groove or the like is used. 44 is output. 43-4 is an adder circuit for adding the output signal of the adder circuit 43-1 and the output signal of the adder circuit 43-2, and outputs an information reproduction signal 45-1. Reference numeral 45-2 denotes an inverted output of the information reproduction signal 45-1, which is used to remove noise mixed in the wiring. Reference numeral 46-1 denotes an adding circuit for adding output signals from the c terminal and the e terminal, and 46-2 denotes an adding circuit for adding output signals from the d terminal and the f terminal. 46-3 is a differential circuit for subtracting the output signal of the adder circuit 46-1 and the output signal of the adder circuit 46-2, and the output signal 47 is used when an optical disc having guide pits is used. A track deviation detection signal can be obtained. By supplying these focus error detection signals and track error detection signals to the coil of the lens actuator 11, and driving the focus lens 15 attached to the lens actuator 11 in the optical axis direction and the disk radial direction, automatic focus control or Track following control can be achieved. Therefore, information can be recorded and recorded on the optical disk 2 by modulating the light intensity of the laser beam 12 emitted from the semiconductor laser chip 13 with the information recording signal. Further, by keeping the light intensity of the laser beam 12 emitted from the semiconductor laser chip 13 constant, the information recorded on the optical disc 2 can be reproduced from the information reproduction signal 45-1.
[0028]
Further, the laser module 50 shown in the second embodiment of FIG. 5 can be used instead of the laser module 8 shown in the first embodiment. The longitudinal direction of the package 51 of the laser module 50 has a circular shape, and rotation adjustment can be easily performed when the laser module 51 is attached to the optical head. Similar to the laser module 8 described with reference to FIG. 2, a plurality of lead wires 22 are passed through a package 51 formed of a material having good thermal conductivity such as aluminum nitride in order to transmit an electric signal. Inside the package 51 is a light receiving element substrate 54 made of silicon or the like and an electronic circuit substrate 28. A recess 25 is formed in the substantially central portion of the light receiving element substrate 24 by etching or the like, and the semiconductor laser chip 13 is mounted in the recess 25. Four light receiving elements 26 are formed on the upper side of the recess 25, and four sets of two-divided light receiving elements 27 are formed on the lower side. Six amplifiers 29 are formed on the electronic circuit board 28. The light receiving element substrate 54 is made smaller than the light receiving element substrate of the first embodiment, and the lead wires 22-6, 22-9, and 22-10 on the right side of the package 51 are extended in the direction of the electronic circuit board 28 in the package 51. The electronic substrate 28 is directly connected with a metal wire. Thereby, a part of the input or output of the electronic circuit board 28 arranged on the left side of the package can be connected to the lead wire on the right side of the package.
[0029]
Although the shape of the light receiving element of the first and second embodiments is different from the shape of the light receiving element of the light emitting and receiving unit disclosed in the above-mentioned Japanese Patent Laid-Open No. 06-076340, the light receiving element is connected to the electronic circuit. Since the number of signal lines is six, the laser module of the present invention can be changed by changing the shape of the light receiving element, the diffraction grating, and the signal processing method shown in FIG. 4 shown in the first and second embodiments. It can be applied to the light emitting / receiving unit disclosed in Japanese Patent Laid-Open No. 06-076340. It is also possible to form the signal processing circuit shown in FIG. 4 on the electronic circuit board 28 of the first embodiment or the second embodiment using today's highly integrated technology of electronic circuits.
[0030]
Next, a third embodiment of the present invention will be described with reference to FIGS.
[0031]
FIG. 6 is a side view of an optical disc apparatus 61 using the present invention. 62 denotes an optical disk. Specifically, a laser wavelength suitable for recording and reproduction is about 780 nm and a substrate thickness of 1.2 mm is a CD-ROM disk or CD-R disk or a laser wavelength suitable for recording and reproduction. A DVD disk having a substrate thickness of about 660 nm and a substrate thickness of 0.6 mm is shown. An optical head 65 can be moved in the radial direction of the optical disk 2 on the rail 7 by an access mechanism 6 constituted by a voice coil motor and a pulley. In the optical head 65, a two-laser module 68, a collimating lens 9, a mirror prism 10, and a lens actuator 11 are incorporated. The two laser module 68 incorporates a semiconductor laser chip 63a that emits a laser beam 62a having a wavelength of about 660 nm and a semiconductor laser chip 63b that emits a laser beam 62b having a wavelength of about 780 nm. The lens actuator 11 is provided with a composite element 14 and a focus lens 15 in which a quarter-wave plate and a polarization diffraction grating are combined.
[0032]
FIG. 7 shows the structure of the two laser module 68. Reference numeral 71 denotes a package having a plurality of lead wires 72 penetrating in order to transmit an electrical signal. Inside the package 71 is a light receiving element substrate 74 and an electronic circuit substrate 78. A concave portion 75 is formed by etching or the like in the substantially central portion of the light receiving element substrate 74, and the semiconductor laser chip 63a and the semiconductor laser chip 63b are mounted on the concave portion 75. Eight light receiving element groups 76 are formed on the lower side of the recess 75, and four sets of two divided light receiving element groups 77 are formed on the upper side. Eight amplifiers 79 are formed on the electronic circuit board 78. For the purpose of explanation, the 14 lead wires 72 include 72-1, 72-2,..., 72-7 from the upper left side to the lower side, 72-8, 72-9 from the upper right side to the lower side. ..., serial number 72-14.
[0033]
FIG. 8 is an enlarged view of the light receiving element substrate 74. For the sake of explanation, the pads on the right side of the light receiving element substrate 74 are assigned serial numbers A1, A2, A5, A6 from the top to the bottom, and the pads on the left side of the light receiving element substrate 74 are directed from the top to the bottom. B1, B2,..., B11 are given serial numbers. FIG. 9 is an enlarged view of the electronic circuit board 78. For purposes of illustration, the pads on the right side of the electronic circuit board 78 are numbered serially C1, C2,..., C11 from top to bottom, and the pads on the left side of the electronic circuit board 78 are top to bottom. The serial numbers D1, D2,... Further, in order to identify the eight amplifiers 79, M1 to M7 serial numbers are assigned to the amplifiers that convert the signals of the pads C3 to C9 into electric signals, and the amplifiers that add the output signals of the amplifiers M4 to M7 are M8. And The four pads A1, A2, A5, A6 on the right side of the light receiving element substrate 74 in FIG. 8 are the lead wires 72-8, 72-9, 72-13, 72- on the right side of the package 71 shown in FIG. 14 is connected with a metal wire by a wire bonding apparatus. The semiconductor laser chip 63a and the semiconductor laser chip 63b arranged on the light receiving element substrate 74 in FIG. 8 are connected to the lead wires 72-11 and 72-10 on the right side of the package 71 shown in FIG. Has been. The pads B1 to B11 on the left side of the light receiving element substrate 74 in FIG. 8 are connected to the pads C1 to C11 on the right side of the electronic circuit board 78 in FIG. 9 by metal wires as shown in FIG. Yes. The pads D1 to D7 on the left side of the electronic circuit board 78 of FIG. 9 are connected to the left lead wires 72-1 to 72-7 of the package 71 shown in FIG. The lead wire 72-13 on the right side of the package 71 is an electrically common ground line for the light receiving element substrate 74 and the electronic circuit board 78, and is connected to the pad A5 on the right side of the light receiving element substrate 74. The left side pad B10 of 74 is also connected to the right side pad C10 of the electronic circuit board 78. The applied voltage required to operate the light receiving elements 76 and 77 of the light receiving element substrate 74 or the amplifier 79 of the electronic circuit board 78 is passed from the lead wire 72-9 on the right side of the package 71 through the pad A2 on the right side of the light receiving element substrate 74. The light is supplied to the light receiving elements 76 and 77, and further supplied from the left pad B1 of the light receiving element substrate 74 to the amplifier 79 through the right pad C1 of the electronic circuit board 78. Electric power necessary for causing the semiconductor laser chip 63a or the semiconductor laser chip 63b disposed on the light receiving element substrate 74 to emit light is supplied from the lead wire 72-11 or 72-10 on the right side of the package 71.
[0034]
When a DVD disk is inserted into the optical disk device 61, an electrical signal is supplied from the lead wire 72-11 on the right side of the package 71 to the semiconductor laser chip 63a, and the semiconductor laser chip 63a has a wavelength of about A 660 nm laser beam 62a is emitted. The inclined surface of the recess 75 is a mirror surface 75 ′ having an angle of about 45 degrees, and the laser beam 62 a emitted from the semiconductor laser chip 63 a is reflected by a point 81 a on the mirror surface 75 ′ and emitted from the two laser module 68. In FIG. 6, the laser beam 62 a emitted from the two laser module 68 becomes a parallel light beam by the collimator lens 9, is reflected by the mirror prism 10, and enters the composite element 14 and the focus lens 15 incorporated in the lens actuator 11. The laser beam 63 a reflected by the optical disk 62 is separated into four + 1st order diffracted lights and four −1st order diffracted lights by the four-divided diffraction grating of the composite element 14, and is condensed by the collimator lens 9. Are focused as eight spots on the surface of the light receiving element substrate 74. 8 indicates four spots of + 1st order diffracted light focused on the surface of the light receiving element substrate 74, and the four spots 82a are received by the lower four light receiving elements 84a of the light receiving element group 76, respectively. Detection signals from the four light receiving elements 84a are sent to pads B6, B7, B8, and B9, respectively. Reference numeral 83 a denotes four spots of −1st order diffracted light focused on the surface of the light receiving element substrate 74, and the four spots 83 a are respectively received by the two sets of light receiving elements 85 a on the lower side of the light receiving element group 77. The output terminals of the two sets of light receiving elements 85a are connected as shown in the figure and synthesized into two detection signals, and the two detection signals are sent to pads B3 and B4. On the other hand, when a CD-ROM disc or CD-R disc is inserted into the optical disc device 61, an electrical signal is supplied from the lead wire 72-10 on the right side of the package 71 to the semiconductor laser chip 63b. 8 emits a laser beam 62b having a wavelength of about 785 nm in the left direction of the drawing. The laser beam 62b emitted from the semiconductor laser chip 63b is reflected at the point 81b on the mirror surface 75 ′ and emitted from the two laser module 68. The laser beam 62b follows the same path as the laser beam 62a described above, and is separated into four + 1st order diffracted lights and four −1st order diffracted lights by the four-part diffraction grating of the composite element 14, and a light receiving element inside the two laser module 68. Focus as 8 spots on the surface of the substrate 74. 8b shows four spots of + 1st order diffracted light focused on the surface of the light receiving element substrate 74. The four spots 82b are respectively received by the upper four light receiving elements 84b of the light receiving element group 76. The detection signals of the four light receiving elements 84b are sent to the pads B6, B7, B8, and B9, respectively. Reference numeral 83 b denotes four spots of −1st order diffracted light focused on the surface of the light receiving element substrate 74, and the four spots 83 b are respectively received by the two sets of light receiving elements 85 b on the upper side of the light receiving element group 77. The output terminals of the two sets of light receiving elements 85b are connected as shown in the figure, combined with two detection signals, and the two detection signals are sent to pads B3 and B4. Reference numeral 86 denotes a monitor light receiving element for detecting the amount of light emitted from the semiconductor laser chip 63a or 63b. The amount of light emitted from the semiconductor laser chip 63a or 63b is detected by, for example, attaching the glass plate 23 shown in FIG. 2B to the package 71 and receiving the laser beam reflected by the glass plate 23. The detection signal of the monitor light receiving element 86 is sent to the pad B5.
[0035]
Four detection signals of the + 1st order diffracted light 82a or 82b received by the light receiving element group 76 are sent from the pads B6, B7, B8, and B9 to the pads C6, C7, C8, and C9 in FIG. 9, and the amplifiers M4, M5, and It is converted into an electric signal by M6 and M7, and is outputted from the lead wires 72-4, 72-5, 72-6 and 72-7 in FIG. 7 via the pads D4, D5, D6 and D7. If these four output signals are input to, for example, the c terminal, d terminal, e terminal, and f terminal of the circuit shown in FIG. 4 of the first embodiment, a push-pull type when an optical disk having a guide groove or the like is used. A track shift detection signal 47 in the case of using an optical disc having a track shift detection signal 44 and guide pits can be obtained. The output signals of the amplifiers M4 to M7 are added by the amplifier M8 and output from the lead wire 72-3 via the pad D3. In this embodiment, the distance between the light receiving element group 76 and the amplifier 79 can be made very short, so that noise mixed in the information reproduction signal output from the amplifier M8 can be reduced. The four detection signals of the first-order diffracted light 83a or 83b received by the light receiving element group 77 in FIG. 8 are sent from the pads B3 and B4 to the pads C3 and C4 in FIG. 9, and converted into electric signals by the amplifiers M1 and M2. Then, the signals are output from the lead wires 72-1 and 72-2 in FIG. 7 via the pads D1 and D2. If these two output signals are input to the terminals a and b of the circuit shown in FIG. 4 of the first embodiment, for example, the defocus detection signal 42-1 and the sum signal 42-2 can be obtained. The detection signal of the monitor light receiving element 86 in FIG. 8 is sent from the pad B5 to the pad C5 in FIG. 9, and is converted into an electric signal by the amplifier M3. The output terminal of the amplifier M3 is connected to the pad C11, the pad C11 is connected to the pad B11 of the light receiving element substrate 74 of FIG. 8, and the pad B11 and the pad A6 are connected by a conductive thin film 95 such as aluminum. The pad A6 is connected to the lead wire 72-14 shown in FIG. Therefore, the monitor detection signal output from the amplifier M3 is output from the lead wire 72-14 on the opposite side of the electronic circuit board 78 via the light receiving element substrate 74. Further, since the amount of semiconductor laser light is large when information is recorded, the output signals of the amplifiers M1 to M7 in FIG. 9 may be saturated. Therefore, the gains of the amplifiers M1 to M7 are switched by the gain switching signal from the pad C2. The pad C2 is connected to the pad B2 of the light receiving element substrate 74 of FIG. 8, the pad B2 and the pad A1 are connected by a conductive thin film 96 such as aluminum, and the pad A1 is the lead wire 72-8 of FIG. Connected with. Therefore, a gain switching signal for switching the gains of the amplifiers M1 to M7 is input via the light receiving element substrate 74 from the lead wire 72-8 on the side opposite to the electronic circuit substrate 78. Normally, the output signal line output from the above-mentioned amplifier, the input signal line that controls the amplifier, the power supply line to the amplifier, and the circuit ground line are usually connected to the lead wire closer to the electronic circuit board. It is. However, in a two-laser module such as an optical head used in an optical disk device, if many lead wires are arranged on one side, the optical head becomes thick. According to this embodiment, the output signal line output from the amplifier, the input signal line for controlling the amplifier, the power supply line to the amplifier, and the ground line of the circuit are connected to the lead wire on the side opposite to the electronic circuit board. By connecting, the number of lead wires on both sides can be made uniform, which is effective in reducing the thickness of an optical head, an optical disk device, or the like.
[0036]
  Next, a fourth embodiment will be described with reference to FIGS. Reference numeral 108 in FIG. 10 denotes a two-laser module with a laser control circuit obtained by adding a laser control circuit board 104 to the two-laser module 68 shown in FIG. The package 71 is the same as that shown in FIG. 7, the photodetecting element substrate 74 is the same as that shown in FIG. 8, and the electronic circuit board 78 is the same as that shown in FIG. FIG. 11 is an enlarged view of the laser control circuit board 104. For the purpose of illustration, the pads on the left side of the laser control circuit board 104 are numbered serially as E1, E2,..., E6 from the top to the bottom. F1, F2,..., F7 are assigned serial numbers from the bottom to the bottom. A lead wire 72-13 on the right side of the package 71 shown in FIG. 10 is an electrically common ground line for the light receiving element substrate 74, the electronic circuit board 78, and the laser control circuit board 104. The laser control circuit board 104 shown in FIG. To the right side pad F6. This common ground line is connected from the pad F6 to the right pad A5 of the light receiving element substrate 74 shown in FIG. 8 through the pad E5, and further from the left pad B10 of the light receiving element substrate 74 to the right pad of the electronic circuit board 78. It is also connected to C10. The applied voltage required to operate the light receiving elements 76 and 77 of the light receiving element substrate 74 or the amplifier 79 of the electronic circuit board 78 and the electronic circuit on the laser control circuit board 104 is the right lead of the package 71 shown in FIG. The line 72-9 is connected to the pad F2 on the right side of the laser control circuit board 104 shown in FIG. This applied voltage line is connected from the pad F2 to the pad A2 on the right side of the pad light receiving element substrate 74 shown in FIG. 8 through the pad E2, and is supplied to the light receiving elements 76 and 77. Further, the pad B1 on the left side of the light receiving element substrate 74 is supplied. To the amplifier 79 through the pad C1 on the right side of the electronic circuit board 78. The lead wire 72-11 on the right side of the package 71 shown in FIG. 10 is connected to the right pad F4 of the laser control circuit board 104 shown in FIG. 11, and causes the semiconductor laser chip 63a or the semiconductor laser chip 63b to emit light. A laser light quantity signal is supplied. Reference numeral 111 denotes a laser driving current amplifying circuit that amplifies a laser light amount signal from several tens mA to about 100 mA. The lead wire 72-10 on the right side of the package 71 shown in FIG. 10 is connected to the right pad F3 of the laser control circuit board 104 shown in FIG. 11, and is used to select the semiconductor laser chip 63a or the semiconductor laser chip 63b. A laser selection signal is provided. A switch circuit 113 for laser selection connects the output current of the current amplifier 111 to the pad E3 or the pad E4 according to the laser selection signal. The pad E3 is connected to the semiconductor laser chip 63b arranged on the light receiving element substrate 74 shown in FIG. 8, and the pad E4 is connected to the semiconductor laser chip 63a arranged on the light receiving element substrate 74 shown in FIG. Therefore, according to the laser selection signal input to the lead wire 72-10, either of the semiconductor laser chips 63a or 63b is caused to emit light with a light amount corresponding to the laser light amount signal input to the lead wire 72-11. it can. Further, the lead wire 72-12 on the right side of the package 71 shown in FIG. 10 is connected to the pad F5 on the right side of the laser control circuit board 104 shown in FIG. A signal is input. The high frequency superposition circuit 112 inputs a high frequency transmission current to the current amplifier when the high frequency superposition on / off signal is on. Therefore, the amount of light emitted from the semiconductor laser chip 63a or 63b can be modulated at a high frequency in accordance with the high frequency superimposed on / off signal input to the lead wire 72-11, and the noise of the semiconductor laser can be reduced. . The detection signal of the monitor light-receiving element 86 shown in FIG. 8 is converted into an electric signal by the amplifier M3 of the electronic circuit board 78, and then passes through the conductive thin film 95 of the light-receiving element substrate 74 from the pad A6 in FIG. Sent to pad E6. The pad E6 and the pad F7 are connected by a conductive thin film 105 such as aluminum, and the pad F7 is connected to the lead wire 72-14 of FIG. Therefore, the detection signal for monitoring output from the amplifier M3 is output from the lead wire 72-14 on the opposite side of the electronic circuit board 78 via the light receiving element board 74 and the laser control circuit board 104. Further, since the amount of semiconductor laser light is large when information is recorded, the output signals of the amplifiers M1 to M7 in FIG. 9 may be saturated. Therefore, the gains of the amplifiers M1 to M7 are switched by the gain switching signal from the pad C2. The pad C2 of FIG. 9 is connected to the pad E1 of the laser control circuit board 104 shown in FIG. 11 from the pad A1 via the light receiving element substrate 74. The pad E1 and the pad F1 are connected by a conductive thin film 106 such as aluminum, and the pad F1 is connected to the lead wire 72-8 in FIG. Therefore, a gain switching signal for switching the gains of the amplifiers M1 to M7 is input from the lead wire 72-8 opposite to the electronic circuit board 78 via the laser control circuit board 104 and the light receiving element board 74. In the optical disk device, in order to reduce the noise of the semiconductor laser during information reproduction, a current of several tens of mA is modulated to a high frequency of about several hundred MHz and supplied to the semiconductor laser chip. When recording information, a current of about 100 mA is modulated to about several tens of MHz according to the recorded information and supplied to the semiconductor laser chip. On the other hand, since the detection current output from the light receiving element is on the order of μA, an amplifier or the like formed on the electronic circuit board must convert a minute current into a voltage signal with low noise. For this reason, when an electronic circuit such as an amplifier and a laser control circuit are mixed on the same substrate, noise tends to be mixed into the electronic circuit such as an amplifier. According to the present embodiment, the electronic circuit board, the light receiving element board, and the laser control board are arranged in this order in the package, and the electronic circuit board and the laser control board are separated from each other, so that noise mixed in the electronic circuit can be reduced. In addition, since the electronic circuit board, the light receiving element board, and the laser control board are arranged in the longitudinal direction of the package, it is effective in reducing the thickness of the optical head, the optical disk device, and the like. Furthermore, by connecting the output signal line output from the above-mentioned amplifier, the input signal line for controlling the amplifier, the power supply line to the amplifier and the ground line of the circuit to the lead wire on the side opposite to the electronic circuit board, Since the number of lead wires on both sides can be made uniform, an effect can be obtained by reducing the thickness of an optical head, an optical disk device or the like.As another embodiment, a light receiving element substrate on which a light receiving element is formed, an electronic circuit board that performs processing such as amplification of an electric signal output from the light receiving element, and a plurality of lead wires that output or input the electric signal ( Or connection line ) Or lead terminal ( Or connection terminal ) An opto-electronic module comprising a light receiving element substrate and an electronic circuit board housed in a package, the package having a long shape in one direction having a long side and a short side, and lead wires on both sides of the short side Or it has a lead terminal, arranges the light receiving element substrate and the electronic circuit board side by side in the direction of the long side of the package, and part of the electrical connection line to the electronic circuit board is the side where the electronic circuit board is arranged Connected to lead wire or lead terminal on opposite side. Alternatively, a package in which a plurality of connection lines or connection terminals for outputting or inputting electric signals are provided on opposite sides, a light receiving element substrate having a light receiving element, and an electronic circuit that electronically processes the electric signal output from the light receiving element In an opto-electronic module having a substrate, a part of an electrical connection line to the electronic circuit board is connected to the connection line or the connection terminal on the side opposite to the side on which the electronic circuit board is arranged did. In another embodiment, a semiconductor laser element is mounted on the light receiving element substrate. In another embodiment, a plurality of semiconductor laser elements having different oscillation wavelengths are mounted on the light receiving element substrate. In another embodiment, a laser control circuit board, a light receiving element board, and an electronic circuit board for controlling the amount of light emitted from the semiconductor laser element are arranged in the long side direction of the package in this order. In another embodiment, a light receiving element substrate on which a light receiving element is formed, an electronic circuit board that performs processing such as amplification of an electric signal output from the light receiving element, and a plurality of lead wires that output or input an electric signal or In an optoelectronic module comprising a light receiving element substrate and an electronic circuit board in a package, the package has a long shape in one direction having a long side and a short side, on both sides of the short side. It has a lead wire or lead terminal, the light receiving element substrate and the electronic circuit board are arranged side by side in the direction of the long side of the package, and a part of the electrical connection line to the electronic circuit board is arranged on the side where the electronic circuit board is arranged The light receiving element substrate was relayed and connected to the lead wire or lead terminal on the opposite side. In another embodiment, a semiconductor laser element is mounted on the light receiving element substrate. In another embodiment, a plurality of semiconductor laser elements having different oscillation wavelengths are mounted on the light receiving element substrate. In another embodiment, a laser control circuit board for controlling the amount of light emitted from the semiconductor laser element, a light receiving element board, and an electronic circuit board are arranged side by side in the direction of the long side of the package. A part of the electrical connection line was connected to the lead wire or the lead terminal on the laser control circuit board side by relaying the light receiving element substrate and the laser control circuit board. In another embodiment, a light emitting and receiving element substrate on which a light receiving element is formed and further mounted with a semiconductor laser element, an electronic circuit board that performs processing such as amplification of an electric signal output from the light receiving element, and light emission of the semiconductor laser element Laser control times to control the amount of light And a package having a plurality of lead wires or lead terminals for outputting or inputting electric signals, and the package is long in one direction having a long side and a short side, and the plurality of lead wires or lead terminals are short. The laser control circuit board, the light emitting / receiving element substrate, and the electronic circuit board are arranged in the long side direction in this order. In another embodiment, a part of the electrical connection line to the electronic circuit board is connected to the side lead wire or lead terminal on which the laser control circuit board is arranged, or the electrical connection line to the laser control circuit board is connected. A part was connected to the side lead wire or lead terminal on which the electronic circuit board was placed. In another embodiment, a part of the electrical connection line to the electronic circuit board is relayed to the side lead wire or lead terminal on which the laser control circuit board is arranged, and the light emitting / receiving element substrate and / or the laser control circuit board is relayed. Or a part of the electrical connection line to the laser control circuit board is connected to the side lead wire or the lead terminal on which the electronic circuit board is arranged by relaying the light emitting / receiving element substrate and / or the electronic circuit board.
[0037]
【The invention's effect】
As described above, according to the present invention, a light-receiving element, an electronic circuit that electronically processes an electrical signal output from the light-receiving element, a photo-electronic module in which a laser light source and the like are housed in one package, and In an optical head or an optical disk apparatus using the same, the light receiving sensitivity of the light detection element can be increased, the speed of the electronic circuit can be increased, or the noise can be reduced. An opto-electronic module suitable for reducing the thickness of the apparatus, and an optical head or an optical disk apparatus using the same can be realized.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an optical disc apparatus according to a first embodiment of the present invention.
FIG. 2 is a block diagram of the laser module in FIG.
FIG. 3 is a grating pattern diagram of the diffraction grating in FIG.
FIG. 4 is a block diagram of an electronic circuit in the first embodiment.
FIG. 5 is a block diagram of a laser module according to a second embodiment of the present invention.
FIG. 6 is a configuration diagram of an optical disc apparatus according to a third embodiment of the present invention.
7 is a block diagram of the two-laser module in FIG.
8 is a configuration diagram of the light receiving element substrate in FIG. 7;
FIG. 9 is a block diagram of the electronic circuit board in FIG.
FIG. 10 is a configuration diagram of a two-laser module according to a fourth embodiment of the present invention.
11 is a block diagram of the laser control circuit board in FIG.
[Explanation of symbols]
1, 61 ... Optical disk device
2,62 ... optical disc
5,65 ... Optical head
8, 50 ... Laser module
68, 108 ... 2 laser modules
21, 51, 71 ... package
22, 72 ... Lead wire
13, 63a, 63b ... Semiconductor laser chip
24, 74 ... Light-receiving element substrate
26, 27, 76, 77... Light receiving element
28, 78 ... Electronic circuit board
29,79… Amplifier
104 ... Laser control circuit board
34, 35, 36, 95, 96 105, 106 ... conductive thin film

Claims (9)

  A light-receiving element substrate on which the light-receiving element is formed, an electronic circuit board that performs processing such as amplification of an electric signal output from the light-receiving element, a package having a plurality of lead wires or lead terminals for outputting or inputting the electric signal, and In the opto-electronic module in which the light receiving element substrate and the electronic circuit board are housed in the package, the package has a long shape in one direction having a long side and a short side, and is formed on both sides of the short side. The light receiving element substrate and the electronic circuit board are arranged side by side in the direction of the long side of the package, and a part of the electrical connection line to the electronic circuit board is An optical-electronic module, wherein the light receiving element substrate is relayed and connected to a lead wire or a lead terminal opposite to the side on which the electronic circuit substrate is disposed.   2. The opto-electronic module according to claim 1, wherein a semiconductor laser element is mounted on the light receiving element substrate.   3. The opto-electronic module according to claim 2, wherein a plurality of semiconductor laser elements having different oscillation wavelengths are mounted on the light receiving element substrate.   4. The opto-electronic module according to claim 3, wherein a laser control circuit board for controlling the amount of light emitted from the semiconductor laser element, the light receiving element board, and the electronic circuit board are arranged side by side in the long side direction of the package. And a part of the electrical connection line to the electronic circuit board is connected to the lead wire or lead terminal on the laser control circuit board side through the light receiving element board and the laser control circuit board. An opto-electronic module characterized by that.   An optical head using the opto-electronic module according to claim 1.   An optical disc apparatus using the optical head according to claim 5.   A light-emitting / receiving element substrate on which a light-receiving element is formed and further mounted with a semiconductor laser element, an electronic circuit board that performs processing such as amplification of an electric signal output from the light-receiving element, and the amount of light emitted from the semiconductor laser element are controlled And a package having a plurality of lead wires or lead terminals for outputting or inputting electric signals, the package having a long shape in one direction having a long side and a short side. Wires or lead terminals are arranged on both sides of the short side, arranged in the direction of the long side in the order of the laser control circuit board, the light emitting and receiving element substrate, and the electronic circuit board, and connected to the electronic circuit board Some of the electrical connection lines are connected to the light emitting / receiving element substrate and / or the laser control circuit board on the side lead wire or lead terminal on which the laser control circuit board is disposed. Or a part of the electrical connection line to the laser control circuit board is connected to the light emitting / receiving element substrate and / or the side lead wire or the lead terminal on which the electronic circuit board is disposed. An optoelectronic module characterized in that it is connected via an electronic circuit board.   An optical head using the optical-electronic module according to claim 7.   An optical disk apparatus using the optical head according to claim 8.

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