JP4385982B2 - Optical device - Google Patents

Description

  The present invention relates to an optical device that constitutes an optical pickup apparatus that performs recording or reproduction on an information recording medium such as an optical disk, and relates to an optical device having a function corresponding to information recording media of a plurality of standards.

  Conventionally, various optical discs have been proposed as information recording media. As such an optical disc, an optical disc of “DVD” (Digital Versatile Disc) standard having a recording capacity approximately seven times that of an optical disc of “CD” (Compact Disc) standard has been rapidly spread in recent years.

  Furthermore, optical disc standards on which a user can record information signals, such as so-called “DVD-RAM”, “DVD-R”, “DVD-RW”, “+ R”, “+ RW”, are also personal computers (PCs). ) And recording media for video recorders are rapidly spreading.

  On the other hand, with regard to “CD” standard optical discs, the standard of optical discs on which information signals can be recorded by the user, such as so-called “CD-R”, has been widely used. In addition, “BD” (Blu-ray Disc) corresponding to high-definition video signals has been proposed as an optical disc standard that allows users to record information signals from the beginning of the proposal.

  As described above, as an information recording medium, an optical disk using a light beam of 650 nm wavelength band that is “DVD” standard, an optical disk using a light beam of 780 nm wavelength band that is “CD” standard, and a light beam of another wavelength band. Any of the optical disks to be used is required to have a function that allows the user to record an information signal.

  In an optical pickup device that records or reproduces information with respect to an optical disc, an optical device including a high-power semiconductor laser light source that supports information recording is used on the assumption that the optical disc can be recorded. Furthermore, in order to realize high-speed recording / reproduction, it is required to further increase the output of the semiconductor laser light source and to increase the bandwidth of the circuit for processing the output signal from the light receiving element.

  Further, such an optical device is required to support a plurality of standard optical discs and maintain good characteristics in the recording / reproducing operation for each standard optical disc. Further, with the diversification of the use of optical discs, highly portable optical disc devices are required. With respect to optical pickup devices and optical devices constituting the optical pickup devices, while maintaining high performance, the size and weight can be reduced. Simplification and lower prices are required.

  From the standpoint of ensuring reliability while meeting the demands of miniaturization, weight reduction, simplification, and cost reduction, an optical device that constitutes an optical pickup device is a light receiving device that incorporates a circuit unit that performs amplification and computation. The “PDIC”, which is an element, and a semiconductor laser light source are integrated, and further, an optical path conversion element such as an optical path conversion mirror, an optical path branching element, and a hologram element having a lens function are integrated in this “PDIC”. An optical device has been proposed.

  For example, Patent Document 1 describes an optical device previously proposed by the present applicant. This optical device is, for example, an optical device corresponding to a plurality of optical discs of “CD” standard and “DVD” standard. As shown in FIG. Both the light in the 780 nm band of the “CD” standard and the light in the 650 nm band of the “DVD” standard can be received by a plurality of light receiving elements 103 arranged on the same light receiving element substrate 102 to perform signal detection. It is possible. The plurality of light receiving elements 103 includes a plurality of light receiving portions that receive return light of the main beam from the optical disc, and a plurality of light receiving portions that receive return light of the sub beam from the optical disc. The hologram element 101 is divided into two regions 101L and 101R having different diffraction directions at the center, and diffracts incident light in different directions and guides the light to each light receiving unit.

  The optical device also includes a semiconductor laser light source 104 that emits light in the 780 nm band of the “CD” standard on the light receiving element substrate 102 as a light emitting function. The light emitted from the semiconductor laser light source 104 is reflected by the optical path conversion mirror 105 disposed on the light receiving element substrate 102 and is emitted to the optical disc side through the hologram element 101. In this optical path conversion mirror 105, a part of the light emitted from the semiconductor laser light source 104 is transmitted. The light transmitted through the optical path conversion mirror 105 is received by the front monitor light receiving element 106 in order to control the amount of emitted light. The front monitor light receiving element 106 is also disposed on the light receiving element substrate 102.

  In this optical device, a plurality of light receiving elements 103 for performing signal detection include an element that receives return light from an optical disk of “CD” standard, and an element that receives return light from an optical disk of “DVD” standard. Are common elements.

  Further, the applicant of the present application has proposed an optical device in which the light receiving surface is further divided as shown in FIG. 7 as an improvement of the optical device. That is, in this optical device, when a “DVD” double-layer disc is used, the sub-beam light receiving unit 107 that is easily affected by an offset or the like due to the irradiation of unnecessary light is returned to the sub-beam when the “DVD” is reproduced. It is divided into a light receiving portion 107a that receives light and a light receiving portion 107b that receives the return light of the sub-beam during “CD” reproduction. In order to cancel out the unnecessary light component, a differential operation is performed in a circuit unit including a plurality of subtractors 108 with respect to outputs of the divided and adjacent light receiving units 107a and 107b. Unnecessary light is canceled by this differential calculation because the light receiving portions 107a and 107b are irradiated with substantially the same amount of light.

  That is, at the time of “DVD” reproduction, a normal sub push-pull signal (Normal SubPP) is generated by subtraction in the first subtractor 108a for the output from the light receiving unit 107a receiving the return light of the sub beam, and the sub beam A cancel signal is generated by subtraction in the second subtractor 108b for the output from the light receiving unit 107b that does not receive the return light. Then, the third subtracter 108c generates a sub push-pull (OC-SubPP) signal from which the offset is removed by subtracting a cancel signal from the normal sub push-pull signal (Normal SubPP).

  At the time of “CD” reproduction, a normal sub push-pull signal (Normal SubPP) is generated by subtraction in the second subtractor 108b for the output from the light receiving unit 107b receiving the return light of the sub beam, and the sub beam A cancel signal is generated by subtraction in the first subtractor 108a for the output from the light receiving unit 107a that does not receive the return light. Then, the third subtracter 108c generates a sub push-pull (OC-SubPP) signal from which the offset is removed by subtracting a cancel signal from the normal sub push-pull signal (Normal SubPP).

  In this optical device, the sub-push pull (OC−) in which the offset is removed in any case by switching the polarity of subtraction in the third subtractor 108c between “DVD” reproduction and “CD” reproduction. SubPP) signal can be obtained. Therefore, if there is a signal for determining whether “DVD” is being reproduced or “CD” is being reproduced, the polarity of subtraction in the third subtractor 108 c can be automatically switched based on this signal. It is.

  Patent Document 2 also describes an optical device previously proposed by the present applicant. As shown in FIG. 8, this optical device has two semiconductor laser light sources 104 a and 104 b for “DVD” and “CD” on a light receiving element substrate 102.

  In this optical device, a tilting mirror 105a is provided as an optical path conversion mirror so that light emitted from each of the semiconductor laser light sources 104a and 104b enters the objective lens 109, respectively. The tilting mirror 105a is driven in a direction suitable for each state during “DVD” reproduction and “CD” reproduction. That is, at the time of “DVD” reproduction, only the “DVD” semiconductor laser light source 104 a is driven, and the emitted light from the “DVD” semiconductor laser light source 104 a is reflected by the tilting mirror 105 a to be reflected on the objective lens 109. Incident. During the “CD” reproduction, only the “CD” semiconductor laser light source 104b is driven, and the emitted light from the “CD” semiconductor laser light source 104b is reflected by the tilting mirror 105a and is reflected on the objective lens 109. Incident.

  The tilting mirror 105a is driven using the driving current or voltage of each of the semiconductor laser light sources 104a and 104b, so that it is not necessary to separately supply a switching drive signal from the outside.

International Publication No. WO2004 / 003901 Pamphlet JP 2004-86954 A

  By the way, in the above-described conventional optical device, as shown in FIG. 6, the return light of the sub beam at the time of “DVD” reproduction and the return light of the sub beam at the time of “CD” reproduction are received by the same light receiving element. In this case, since the return lights having different wavelengths are diffracted at different angles in the hologram element 101, it is necessary to sufficiently increase the light receiving area of the light receiving element in order to receive both return lights. If the light receiving area of the light receiving element is increased, the amount of unnecessary light received, such as flare generated in a “double layer DVD” or an objective lens corresponding to two wavelengths, is relatively increased. Then, an offset (tracking offset: TEoffset) or the like of the tracking error signal generated based on the return light of the sub beam increases, leading to deterioration in servo operation accuracy and a decrease in the dynamic range of the circuit unit. .

  As shown in FIG. 7, when the light receiving element that receives the return light of the sub beam at the time of “DVD” reproduction and the light receiving element that receives the return light of the sub beam at the time of “CD” reproduction are divided, The problem of a relative increase in the amount of unnecessary light received can be avoided. However, in this optical device, it is necessary to switch the polarity of subtraction in the circuit unit according to the standard of the optical disk to be used, and it is possible to supply a predetermined control signal for such polarity switching from the outside. Necessary. Then, this optical device loses versatility as an optical device, and the number of wires between the optical device and an external device increases, so that it is difficult to reduce the size of the device configuration. .

  Here, as described in Patent Document 2, it is conceivable to use the driving voltage of the semiconductor laser light source as a switching signal. However, in particular, the drive of the semiconductor laser light source in the optical device for recording and reproduction includes a lot of non-direct current high-frequency components such as using a complicated drive waveform called strategy during recording and using high-frequency weight during reproduction. Since a driving voltage having a waveform is used, there is a problem that it is difficult to secure a stable operation of the circuit unit when such a laser driving system is connected to a circuit unit that requires a high S / N ratio.

  Further, in an optical device compatible with both the “CD” and “DVD” standards, a circuit used when recording / reproducing with respect to an “CD” standard optical disk and a circuit used when recording / reproducing with respect to an “DVD” standard optical disk Can be separated at least in part. In this case, the circuit unit corresponding to one of the standards is not used at the time of recording / reproducing with respect to the optical disk of the other standard. Therefore, if power is always supplied to both circuit units, the current consumption becomes excessive. In particular, in a portable device (mobile device) that requires power saving, a problem arises that the operating time by the battery is shortened due to excessive current consumption.

  In such a case, it is conceivable to cut off the power supply to a part of the circuit portion by a control signal supplied from the outside (so-called sleep function). However, if the control signal is supplied from the outside in this way, the number of wirings between the optical device and the external device increases, and it becomes difficult to reduce the size of the device configuration.

  Therefore, the present invention has been proposed in view of the above-described circumstances, and in an optical device having a function corresponding to a plurality of information recording media of a plurality of standards, “double layer DVD” and an objective lens corresponding to two wavelengths. The tracking error signal offset caused by unnecessary light such as flare generated in the above is suppressed, the servo operation is highly accurate and a high dynamic range is secured, and the operation of the circuit section and the execution of the sleep operation are performed. For this reason, it is no longer necessary to supply a control signal from the outside, so that versatility as an optical device is ensured, and the number of wirings to and from an external device does not increase, thereby enabling downsizing of the device configuration. Furthermore, it is possible to prevent the laser drive system and the circuit unit from being directly electrically connected, and to stabilize the operation of the circuit unit and maintain a high S / N ratio. And an object thereof is to provide an optical device adapted.

  In order to solve the above-described problems and achieve the above object, an optical device according to the present invention has any one of the following configurations.

[Configuration 1]
In an optical device having a light emitting / receiving function and used for recording or reproduction of an information recording medium, a semiconductor laser light source that emits light of a first wavelength, a light receiving element for monitoring that detects the amount of light emitted from the semiconductor laser light source, and information a first of the first region and a signal-detecting light-receiving element which have a second region for receiving light of a second wavelength different from the first wavelength for receiving light wavelength incident from the recording medium, monitor A determination means for determining whether or not the semiconductor laser light source is driven based on an output from the light receiving element, and an output signal from the first area and an output from the second area with respect to an output signal from the signal detecting light receiving element While performing an operation that cancels the signal, the polarity of each output signal in this operation is switched based on the determination result by the determination means, thereby being used for recording or reproduction on the information recording medium. And a circuit portion for performing an operation of subtracting an output signal corresponding to the recording or the light of the other wavelengths that are not used for reproduction from the output signal on the information recording medium corresponding to the light of a wavelength, a semiconductor laser light source, a monitor light-receiving element, signal detection light-receiving element, the circuit portion and the determination means is characterized in that it is provided with monolithically integrated.

[Configuration 2]
In the optical device having the configuration 1, at least two of the monitoring light receiving element, the signal detecting light receiving element, the circuit unit, and the determination unit are provided on the same light receiving element substrate. .

[Configuration 3]
In the optical device having the configuration 1 or the configuration 2, an optical path conversion mirror having a reflection surface that reflects a part of the forward emitted light from the semiconductor laser light source to perform optical path conversion and transmits the remaining part of the forward emitted light. The monitor light-receiving element receives light transmitted through the reflection surface of the optical path conversion mirror, out of the forward light emitted from the semiconductor laser light source.

[Configuration 4]
In the optical device having the configuration 1 or the configuration 2, the light-receiving element for monitoring receives backward emitted light from the semiconductor laser light source.

[Configuration 5 ]
In the optical device having any one of Configurations 1 to 4 , the circuit unit records on the information recording medium with light having one of the first wavelength and the second wavelength based on the determination result by the determination unit. Alternatively, the amplification factor for the output signal from the signal detection light-receiving element is switched between when the reproduction is performed and when the information recording medium is recorded or reproduced with the light of the other wavelength among the wavelengths. It is characterized by this.

  In the optical device according to the present invention, the semiconductor laser light source, the light receiving element for monitoring, the light receiving element for signal detection, the circuit unit, and the determining unit are integrally integrated, and the circuit unit is determined by the determining unit. The operation is switched according to the determination result of whether or not the semiconductor laser light source is driven. For example, the light receiving element that receives the return light of the sub beam at the time of “DVD” reproduction and the light receiving element that receives the return light of the sub beam at the time of “CD” reproduction. And the relative increase in the amount of received unnecessary light can be avoided, and there is no need to supply a control signal for switching the polarity of subtraction in the circuit section from the outside.

  Therefore, this optical device has versatility as an optical device, and the number of wires between the optical device and an external device does not increase, so that the apparatus configuration can be reduced in size.

  Further, in this optical device, since the laser drive system and the circuit unit are not directly electrically connected, the operation of the circuit unit and the high S / N ratio can be maintained.

  That is, the present invention relates to a tracking error signal generated by unnecessary light such as “double layer DVD” or flare generated in an objective lens corresponding to two wavelengths in an optical device having a function corresponding to information recording media of a plurality of standards. The offset is suppressed, the servo operation is highly accurate and a high dynamic range is secured, and it is not necessary to supply a control signal from the outside for switching the operation of the circuit section or executing the sleep operation. As a result, versatility as an optical device is ensured, and the number of wires between the external devices is not increased, so that the size of the device can be reduced. Further, the laser drive system and the circuit unit are electrically connected. To provide an optical device which is prevented from being directly connected to stabilize the operation of a circuit unit and to maintain a high S / N ratio. It is those that can be.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[First Embodiment]
In this embodiment, the optical device according to the present invention is used as a main part of an optical pickup apparatus compatible with optical discs of a plurality of standards such as “CD” standard and “DVD” standard, for example.

  FIG. 1 is a perspective view showing a configuration of a main part of an optical pickup apparatus using the optical device according to the first embodiment of the present invention.

  As shown in FIG. 1, this optical device diffracts incident light by a hologram element 1 to diffract light having a first wavelength of “CD” standard 780 nm band and a second wavelength “DVD”. Any of the standard 650 nm band light can be received by a plurality of light receiving elements 3 arranged on the same light receiving element substrate 2 and signal detection can be performed. The plurality of light receiving elements 3 include a plurality of light receiving portions 3a, 3b, 3c, and 3d that receive the return light of the main beam from the optical disc, and a plurality of light receiving portions 3e, 3f, and 3g that receive the return light of the sub beam from the optical disc. , 3h.

  Note that the hologram element 101 is divided into two regions 1L and 1R having different diffraction directions at the center, and divides incident light into different directions and diffracts them in different directions, thereby receiving the light receiving portions 3a and 3b on one side. , 3e, 3f and the other light receiving portions 3c, 3d, 3g, 3h, respectively.

  In addition, this optical device includes a semiconductor laser light source 4 that emits light in the 780 nm band for the “CD” standard, which is the first wavelength, on the light receiving element substrate 2 as a light emitting function. The semiconductor laser light source 4 is disposed on the light receiving element substrate 2 via a submount 4a. The light emitted from the semiconductor laser light source 4 is reflected by the optical path conversion mirror element 5 disposed on the light receiving element substrate 2 and is emitted to the optical disc side through the grating element 7 and the hologram element 1. In this optical device, the emitted light is split by the grating element 7 into a main beam and a pair of sub beams. The emitted light is condensed and irradiated onto the information recording surface of the optical disc by an optical pickup device optical system (not shown).

  Note that the 650 nm band light of the “DVD” standard, which is the second wavelength, is emitted from a semiconductor laser light source (not shown) installed outside the optical device, and is applied to the information recording surface of the optical disk by the optical pickup device optical system. Condensed and irradiated.

  The optical path conversion mirror element 5 is a prism having a prism shape in which a slope portion on one end side is a reflection surface. In this optical path conversion mirror element 5, a part of the light emitted from the semiconductor laser light source 4 passes through the slope portion and enters the optical path conversion mirror element 5. The light incident on the optical path conversion mirror 5 is received by the front monitor light receiving element 6 which is a monitor light receiving element in order to control the amount of emitted light. The front monitor light receiving element 6 is also disposed on the light receiving element substrate 2.

  In driving the semiconductor laser light source 4, APC (Automatic Power Control) that constantly monitors the amount of emitted light and controls the amount of emitted light to a constant amount is essential. The front monitor light receiving element 6 is used to perform this APC.

  The light detection output from the front monitor light receiving element 6 is obtained only when the “CD” standard semiconductor laser light source 4 emits light, and the external “DVD” standard semiconductor laser light source emits light. This cannot be obtained when the semiconductor laser light source 4 for “CD” standard is turned off. This is because light emitted from the “DVD” standard semiconductor laser light source does not reach the front monitor light-receiving element 6. Therefore, the presence or absence of the light detection output from the front monitor light receiving element 6 serves as an index for discriminating whether the optical disc of the “CD” standard or the “DVD” standard is being used.

  Then, the return light having the first wavelength and the second wavelength reflected by the information recording surface of the optical disc is emitted from the semiconductor laser light source 4 to the optical device and emitted from the optical path conversion mirror element 5. In the opposite direction, as described above, the light is branched by the hologram element 1, receives a lens action, and is received by the plurality of light receiving elements 3 on the light receiving element substrate 2.

  Return light from the optical disk of the main beam is received by a plurality of light receiving elements 3a, 3b, 3c, 3d for signal detection. The plurality of light receiving elements 3a, 3b, 3c, 3d receive both the main beam return light from the “CD” standard optical disc and the main beam return light from the “DVD” standard optical disc. The plurality of light receiving elements 3a, 3b, 3c, and 3d that receive the return light of the main beam are each divided into a plurality of light receiving regions, and independent light detection outputs can be obtained from each region. Yes. These light detection outputs are sent to the circuit unit 10 described later.

  In this optical device, the return light from the sub-beam optical disc is received by a plurality of light receiving elements 3e, 3f, 3g, 3h for detecting a tracking error signal. Each of the plurality of light receiving elements 3e, 3f, 3g, and 3h receives the sub beam return light from the "CD" standard optical disc and the sub beam return light from the "DVD" optical disc. It is divided into areas. An independent photodetection output can be obtained from each of these divided areas. These light detection outputs are sent to the circuit unit 10 described later.

  This optical device is a “PDIC” which is a light receiving element substrate 2 in which a plurality of light receiving elements 3 are formed and a circuit portion 10 is built in a package 8 made of a lead frame which is a wiring board made of metal and a resin casing. Is installed and configured. The lead frame can be divided into a planar substrate obtained by patterning a plurality of electrodes on the surface of an insulator or a metal plate subjected to insulation processing, or a metal plate divided into a plurality of portions electrically separated by punching. What was comprised can also be used. A plurality of terminal pins 9 connected to the electrodes on the lead frame protrude from the package 8.

  A circuit unit 10 is formed on the light receiving element substrate 2. The circuit unit 10 amplifies and calculates the light detection output output from each light receiving element 3 to generate a reproduction signal and various error signals. By using this reproduction signal, it is possible to reproduce the signal from the optical disc, and it is possible to perform various servo operations by using various error signals.

  FIG. 2 is a block diagram showing the relationship between the light receiving element and the circuit unit in the first embodiment of the optical device according to the present invention.

  In this optical device, as shown in FIG. 2, the light detection output S <b> 1 from the front monitor light receiving element 6 is input to a determination circuit 11 serving as a determination unit constituting the circuit unit 10. In this determination circuit 11, the light detection output S1 is compared with a half value of a level corresponding to the average amount of light emitted from the semiconductor laser light source 4 during reproduction of the “CD” standard optical disc as a saddle value, and a binarized signal. S2 is output. This binarized signal S2 is a signal indicating whether or not the semiconductor laser light source 4 is driven. The binarized signal S2 is sent to the offset cancel circuit 12 that constitutes the circuit unit 10.

  In each of the plurality of light receiving elements 3e, 3f, 3g, and 3h that receive return light from the sub-beam optical disc, an area 13 that receives sub-beam return light from the "CD" standard optical disc and a "DVD" standard Only one of the areas 14 for receiving the return light of the sub beam from the optical disk exclusively receives the return light from the optical disk. These regions 13 and 14 are electrically separated, and each independently generates a light detection output.

  The output S3 from the region 13 for receiving the return light of the sub beam from the “CD” standard optical disc passes through the IV converter 15 to become a voltage output V1 and is sent to the offset cancel circuit 12. Further, the output S4 from the region 14 for receiving the return light of the sub-beam from the “DVD” standard optical disc passes through the IV converter 16 and becomes a voltage output V2, which is sent to the offset cancel circuit 12.

  FIG. 3 is a block diagram showing a configuration of an offset cancel circuit in this optical device.

  As shown in FIG. 3, the offset cancellation circuit 12 performs a differential operation on the outputs from the divided regions 13 and 14 by a plurality of subtractors 12 a, 12 b, and 12 c in order to cancel unnecessary light components. Do. Unnecessary light is canceled by this differential calculation because the regions 13 and 14 are irradiated with substantially the same amount of light.

  That is, at the time of “CD” reproduction shown in FIG. 3A, the first subtractor 12a subtracts the output from the region 13 of each of the light receiving elements 3e, 3f, 3g, 3h receiving the return light of the sub beam. Thus, a normal sub push-pull signal (Normal SubPP) is generated, and the output from the region 14 of each of the light receiving elements 3e, 3f, 3g, 3h not receiving the sub-beam return light is subtracted by the second subtractor 12b. Thus, a cancel signal is generated. Then, the third subtracter 12c subtracts the cancel signal from the normal sub push-pull signal (Normal SubPP), thereby generating a sub push-pull (OC-SubPP) signal S5 from which the offset is removed.

  Then, at the time of “DVD” reproduction shown in FIG. 3B, the subtractor 12b subtracts the output from the region 14 of each of the light receiving elements 3e, 3f, 3g, 3h receiving the return light of the sub beam. Thus, a normal sub push-pull signal (Normal SubPP) is generated, and the output from the region 13 of each of the light receiving elements 3e, 3f, 3g, 3h not receiving the sub-beam return light is subtracted by the first subtractor 12a. Thus, a cancel signal is generated. Then, the third subtracter 12c subtracts the cancel signal from the normal sub push-pull signal (Normal SubPP), thereby generating a sub push-pull (OC-SubPP) signal S5 from which the offset is removed.

  In this circuit unit 10, the sub push-pull (OC) from which the offset is removed in any case by switching the polarity of subtraction in the third subtractor 12 c between “CD” reproduction and “DVD” reproduction. -SubPP) signal S5 can be obtained. In the offset cancel circuit 12, the polarity of subtraction in the third subtractor 12c is automatically switched based on the binarized signal S2 indicating whether or not the semiconductor laser light source 4 is driven.

  As described above, this optical device does not need to supply a control signal for switching the polarity of subtraction in the third subtractor 12c from the outside, and has a preferable function as a general-purpose component.

  This optical device can also be applied to a reproduction-only optical pickup device, and can also perform a recording operation by modulating the optical output with the semiconductor laser light source 4 having a sufficiently high output. In addition, by further increasing the output of the semiconductor laser light source 4 and widening the circuit portion, it is possible to cope with high speed.

[Second Embodiment]
In this embodiment, in the above-described optical device, the sleep mode operation is switched based on the binarized signal S2 indicating whether or not the semiconductor laser light source 4 is driven.

  FIG. 4 is a block diagram showing the relationship between the light receiving element and the circuit unit in the second embodiment of the optical device according to the present invention.

  In the circuit unit 10 of this optical device, as shown in FIG. 4, the light detection output S <b> 1 from the front monitor light receiving element 6 is input to the determination circuit 11 constituting the circuit unit 10. In this determination circuit 11, the light detection output S1 is compared with a half value of a level corresponding to the average amount of light emitted from the semiconductor laser light source 4 during reproduction of the “CD” standard optical disc as a saddle value, and a binarized signal. S2 is output. This binarized signal S2 is a signal indicating whether or not the semiconductor laser light source 4 is driven. The binarized signal S2 is sent to the “CD” recording / reproducing dedicated circuit 17, the “DVD” recording / reproducing dedicated circuit 18 and the signal output stage circuit 19 which constitute the circuit unit 10.

  The “CD” recording / reproducing dedicated circuit 17 receives the output S3 from the region 13 for receiving the return light of the sub beam from the “CD” standard optical disc, and performs current-voltage conversion and amplification. The “CD” recording / reproducing dedicated circuit 17 needs to be operated only during recording / reproducing of the “CD” standard optical disc.

  The “DVD” recording / reproducing dedicated circuit 18 receives the output S4 from the area 14 that receives the return light of the sub-beam from the “DVD” standard optical disc, and performs current-voltage conversion and amplification. This “DVD” recording / reproducing dedicated circuit 18 needs to operate only when recording / reproducing the “DVD” standard optical disc.

  Therefore, when recording or reproducing is performed on one of the optical discs “CD” and “DVD”, power supply to the circuit corresponding to the other optical disc is cut off, and so-called sleep mode is achieved. It is desirable to plan.

  In this circuit unit 10, the “CD” recording / reproducing dedicated circuit 17 is powered only during recording / reproducing of the “CD” standard optical disc based on the binarized signal S 2 indicating whether or not the semiconductor laser light source 4 is driven. It is configured to control an internal power switch circuit so as to be supplied. The dedicated circuit 18 for recording / reproducing “DVD” is also supplied with power only during recording / reproducing of the “DVD” standard optical disk based on the binarized signal S2 indicating whether or not the semiconductor laser light source 4 is driven. In addition, it is configured to control an internal power switch circuit.

  Further, in this circuit unit 10, the signal output stage circuit 19 also switches the signal path inside based on the binarized signal S <b> 2 indicating whether or not the semiconductor laser light source 4 is driven.

  Further, in this signal output stage circuit 19, based on the binarized signal S2 indicating whether or not the semiconductor laser light source 4 is driven, recording and reproduction of the “CD” standard optical disk and recording and reproduction of the “DVD” standard optical disk are performed. Depending on the time, the amplification gain may be switched by switching the internal constant.

[Third Embodiment]
The optical device according to the present invention is not limited to the configuration using the front monitor light-receiving element 6 as the monitor light-receiving element as in the above-described embodiments, and receives the light beam emitted behind the semiconductor laser light source 4. You may comprise using the light-receiving element for a monitor.

  FIG. 5 is a perspective view showing a configuration of a main part of an optical pickup apparatus using the optical device according to the third embodiment of the present invention.

  In this optical device, as shown in FIG. 5, a monitor light receiving element 20 for receiving a light beam emitted behind the semiconductor laser light source 4 is provided as a monitor light receiving element instead of the front monitor light receiving element 6. ing. The monitoring light receiving element 20 is disposed on a submount 4a to which the semiconductor laser light source 4 is attached.

  An output signal from the monitoring light receiving element 20 is connected to the circuit unit 10 on the light receiving element substrate 12 through wire bonding. In this case, it is desirable that the circuit unit 10 is disposed on the light receiving element substrate 2 in the vicinity of the submount 4a.

  This optical device also has a circuit configuration similar to that shown in FIGS. 2 to 4 except that the above-described front light-receiving element 6 is replaced with the light-receiving element 20 for monitoring. It is not necessary to supply a control signal for switching the polarity of operation in the operation, switching the sleep mode operation, or switching the amplification gain from the outside, and has a preferable function as a general-purpose component.

  The optical device according to the present invention is not limited to an optical pickup device that performs compatible reproduction or recording of an optical disc of “CD” standard and an optical disc of “DVD” standard, and a plurality of wavelengths in the same device. The present invention is applicable to an information recording / reproducing apparatus that uses a light source. Further, the present invention can be applied not only to information recording / reproduction, but also to light receiving / emitting devices such as communication and information processing using a plurality of wavelengths.

It is a perspective view which shows the structure of the principal part of the optical pick-up apparatus using the optical device in the 1st Embodiment of this invention. It is a block diagram which shows the relationship between the light receiving element and circuit part in 1st Embodiment of the optical device which concerns on this invention. It is a block diagram which shows the structure of the offset cancellation circuit in the said optical device. It is a block diagram which shows the relationship between the light receiving element and circuit part in 2nd Embodiment of the optical device which concerns on this invention. It is a perspective view which shows the structure of the principal part of the optical pick-up apparatus using the optical device in the 3rd Embodiment of this invention. It is a perspective view which shows the structure of the principal part of the optical pick-up apparatus using the conventional optical device. It is a block diagram which shows the relationship between the light receiving element and circuit part in the conventional optical device. It is a perspective view which shows the other example of a structure of the principal part of the optical pick-up apparatus using the conventional optical device.

Explanation of symbols

3a, 3b, 3c, 3d Light receiving element for main beam 3e, 3f, 3g, 3h Light receiving element for sub beam 4 Semiconductor laser light source 5 Optical path conversion mirror element 6 Light receiving element for front monitor 10 Circuit unit 11 Determination circuit 12 Light receiving element substrate 20 Monitor Light receiving element S2 binarized signal

Claims (5)

In an optical device having a light emitting / receiving function and used for recording or reproduction of an information recording medium,
A semiconductor laser light source that emits light of a first wavelength;
A light-receiving element for monitoring that detects the amount of light emitted from the semiconductor laser light source;
The first region and the signal detection light-receiving to have the said first second region for receiving light of a wavelength different from a second wavelength for receiving the light of said first wavelength incident from the information recording medium Elements,
Determining means for determining whether or not the semiconductor laser light source is driven based on an output from the light receiving element for monitoring ;
For the output signal from the signal detection light-receiving element, an operation for canceling the output signal from the first region and the output signal from the second region is performed, and the polarity of each output signal in this calculation is By switching based on the determination result by the determination means, the other wavelength not used for recording or reproduction on the information recording medium from the output signal corresponding to the light of one wavelength used for recording or reproduction on the information recording medium A circuit unit that performs an operation of subtracting an output signal corresponding to the light of
With
The semiconductor laser light source, the monitor light-receiving element, wherein the signal-detecting light-receiving element, the circuit portion and the determination means, an optical device characterized by being provided with monolithically integrated. 2. The optical device according to claim 1, wherein at least two of the monitor light-receiving element, the signal detection light-receiving element, the circuit unit, and the determination unit are provided on the same light-receiving element substrate. . An optical path conversion mirror having a reflecting surface that reflects a part of the forward emitted light from the semiconductor laser light source and performs optical path conversion and transmits the remaining part of the forward emitted light,
The light according to claim 1, wherein the light-receiving element for monitoring receives light that has passed through a reflection surface of the optical path conversion mirror among light emitted forward from the semiconductor laser light source. device. The optical device according to claim 1, wherein the light-receiving element for monitoring receives backward emission light from the semiconductor laser light source. The circuit unit performs recording or reproduction on the information recording medium with light of one of the first wavelength and the second wavelength based on a determination result by the determination unit, and The amplification factor for the output signal from the signal detection light-receiving element is switched between when the information recording medium is recorded or reproduced with light of the other wavelength among the wavelengths. The optical device according to any one of claims 1 to 4 .

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