WO2007114372A1 - Optical pickup and information device - Google Patents

Optical pickup and information device Download PDF

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Publication number
WO2007114372A1
WO2007114372A1 PCT/JP2007/057208 JP2007057208W WO2007114372A1 WO 2007114372 A1 WO2007114372 A1 WO 2007114372A1 JP 2007057208 W JP2007057208 W JP 2007057208W WO 2007114372 A1 WO2007114372 A1 WO 2007114372A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
light receiving
return light
optical
recording
Prior art date
Application number
PCT/JP2007/057208
Other languages
French (fr)
Japanese (ja)
Inventor
Naoharu Yanagawa
Masataka Izawa
Takehisa Okuyama
Original Assignee
Pioneer Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pioneer Corporation filed Critical Pioneer Corporation
Priority to JP2008508677A priority Critical patent/JP4695688B2/en
Publication of WO2007114372A1 publication Critical patent/WO2007114372A1/en

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1381—Non-lens elements for altering the properties of the beam, e.g. knife edges, slits, filters or stops
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
    • G11B7/127—Lasers; Multiple laser arrays
    • G11B7/1275—Two or more lasers having different wavelengths
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B2007/0003—Recording, reproducing or erasing systems characterised by the structure or type of the carrier
    • G11B2007/0006—Recording, reproducing or erasing systems characterised by the structure or type of the carrier adapted for scanning different types of carrier, e.g. CD & DVD
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B2007/0003—Recording, reproducing or erasing systems characterised by the structure or type of the carrier
    • G11B2007/0009—Recording, reproducing or erasing systems characterised by the structure or type of the carrier for carriers having data stored in three dimensions, e.g. volume storage
    • G11B2007/0013—Recording, reproducing or erasing systems characterised by the structure or type of the carrier for carriers having data stored in three dimensions, e.g. volume storage for carriers having multiple discrete layers

Definitions

  • the present invention relates to a technical field of an optical pickup that irradiates a laser beam when data is recorded or reproduced on an information recording medium such as a DVD, and an information device including the optical pickup.
  • a multi-layer optical disk or the like that optically records or reproduces an information signal (data) using a laser beam or the like, such as a dual-layer Blu-ray or a dual-layer DVD.
  • Information recording media have been developed.
  • the signal from the selected recording layer may be deteriorated due to the influence of spherical aberration. It tends to narrow the interval.
  • the return light from the multi-layer optical disc is caused by so-called interlayer crosstalk, so that the desired recording layer (hereinafter referred to as “one of the appropriate ones” is selected.
  • Reflected light (hereinafter referred to as “recording layer”) reflected by another recording layer other than one recording layer (hereinafter referred to as “one return light” where appropriate). (Also called “stray light” as appropriate) is also contained at a high level. Therefore, for example, the SZN ratio of signal components such as playback signals may be reduced.
  • a signal component of one return light and a stray light component in a multilayer optical disc are in a trade-off relationship.
  • the stray light component can be lowered to a relatively low level to reduce the effect of stray light, but at the same time, the signal component of one return light is also reduced.
  • the level will be relatively low and the SZN ratio will also decrease.
  • the area of the light-receiving region is increased, it is possible to bring the signal component of one return light to a relatively high level. At the same time, the stray light component also becomes a relatively high level. The technical problem will be that the ratio will also decrease.
  • Non-Patent Document 1 describes a double-layer Blu-ray Disc.
  • the following describes a technique for avoiding the incidence of stray light to a light receiving element by separating the push-pull signal from the signal light by a hologram element in a tracking method during recording or reproduction.
  • Non-Patent Document 2 in order to reduce the influence of stray light contained in signal components from each recording layer of a multilayer information recording medium, it is fixed in a confocal optical system. It describes a technique for spatial filtering (spatial removal) using a pinhole.
  • Patent Document 1 a technique for separating reflected light from each recording layer with high accuracy by utilizing the difference in the angle of the optical axis of the return light of each recording layer force of a two-layer type optical disc. It is described.
  • Non-Patent Document 3 describes, for example, an optical pickup of a multi-layer information recording medium provided with a plurality of light receiving means respectively corresponding to orthogonal optical axes.
  • Patent Document 1 Japanese Patent Laid-Open No. 2005-228436
  • Non-Patent Document 1 "Development of 1-beam tracking system suitable for double-layer Blu-ray disc” Matsushita Electric Industrial Co., Ltd. AV Core Technology Development Center Opto Device Group IEICE Technical Report CPM2005-149 ( 2005-10)) The Institute of Electronics, Information and Communication Engineers ⁇ 31-34
  • Non-Patent Document 2 "3D Multi-layer Bit Recording Memory” Yoshimasa Kawada (Faculty of Engineering, Shizuoka University) Laser Symposium 2005
  • Non-Special Reference 3 “SONY Experimental 3 ⁇ 4etup” ISOM (International Symposium on Optical Memory) Lecture 2004
  • Non-Patent Document 1 As shown in FIG. 14, in a light receiving element for receiving a focus error signal or an RF signal, stray light (“ (See the overlap between Stray light ”and“ Transmitted beam ”), and the SZN ratio of the signal component of the return light from the desired recording layer is reduced due to stray light. There will be technical problems.
  • an optimum pinhole for example, Z, is selected depending on the position of the recording layer or the position where tracking is performed. Since the position in the axial direction changes, there arises a technical problem that it becomes difficult to appropriately spatially filter the influence of stray light.
  • Patent Document 1 Alternatively, according to Patent Document 1 and the like described above, a technical problem arises that it is difficult to manage or control various aberrations. Alternatively, when the recording layer is changed, a technical problem arises that it is necessary to optimize the position in the z-axis direction of the light receiver or the condensing lens that collects the return light.
  • the present invention has been made in view of, for example, the conventional problems described above.
  • an information recording medium such as a multilayer optical disk
  • data can be reproduced with higher accuracy while reducing the influence of stray light.
  • an optical pickup is an optical pickup that performs at least one of recording and reproduction of data on a recording medium including a plurality of recording layers, and a light source that irradiates laser light; An optical system that guides the irradiated laser light to one of the plurality of recording layers, and return light that is reflected by each of the plurality of recording layers due to the guided laser light.
  • a light receiving means for receiving light, a pinhole having a predetermined opening for selectively allowing at least one return light reflected on the one recording layer out of the return light to pass through and receiving the light receiving means, A variable-focus lens for condensing the one return light at a predetermined opening, and first control means for applying a predetermined voltage to the variable-focus lens so as to collect the one return light.
  • the laser light emitted from the light source is applied to one of the plurality of recording layers by an optical system such as an objective lens, a beam splitter, or a prism. Guided and condensed. At the same time, one return light reflected on one recording layer is received by the light receiving means. Therefore, the focused laser beam guided to one recording layer is It is possible to reproduce information pits and marks formed in one recording layer. Therefore, it is possible to reproduce predetermined information with the optical disc power. Alternatively, the focused laser beam can form information pits and marks in one recording layer. Therefore, it is possible to record predetermined information on the optical disc.
  • an optical system such as an objective lens, a beam splitter, or a prism. Guided and condensed.
  • one return light reflected on one recording layer is received by the light receiving means. Therefore, the focused laser beam guided to one recording layer is It is possible to reproduce information pits and marks formed in one recording layer. Therefore, it is possible to reproduce predetermined information with the optical disc power.
  • the focused laser beam can form information pits
  • a predetermined voltage is applied to the variable focus lens under the control of the first control means, so that one return light is focused at a predetermined pinhole position.
  • the “pinhole” according to the present invention includes an opening having a predetermined size, that is, a so-called hole, and spatially filters the laser light by passing through the opening. Means a possible member. Therefore, a given pinhole selectively passes one return light, that is, passes one return light at a relatively high level and spatially filters (spatially removes) stray light. Can be realized more effectively.
  • “selectively receiving one return light” means that the signal level of one return light is received at a relatively high level compared to the signal level of the other return light. It means to do. It may mean that it includes both one return light and the other return light.
  • the size of the pinhole opening may be as large as possible including the return light component, or the signal to noise ratio (Signal to Noise Ratio) may be the best. It may be arbitrarily selectable depending on the usage method. Subsequently, for example, an RF signal corresponding to the data is calculated based on one return light by the calculation means.
  • the stray light when one return light is focused at an opening of a predetermined pinhole, at this condensing point position, only the return light including the maximum amount of one return light component is present. Optionally, it can pass through this predetermined pinhole opening.
  • the stray light since the stray light is not focused, the light diameter of the stray light beam is increased at a predetermined pinhole position. Therefore, since the stray light spreads at the position of the pinhole and cannot pass through the opening of the predetermined pinhole, the stray light component can be spatially filtered to the maximum extent.
  • One aspect of the optical pickup of the present invention further includes second control means for controlling a relative positional relationship between the predetermined opening and the light receiving means.
  • a spatial positional relationship between the predetermined pinhole and the light receiving means (PD) (specifically, a positional relationship in the X-axis, y-axis, or z-axis direction)
  • PD light receiving means
  • the second control means includes a Z-axis direction that is an optical axis direction, an X-axis direction orthogonal to the Z-axis direction, and the Z-axis direction and the Z-axis direction.
  • the relative positional relationship may be controlled based on the Y-axis direction that is orthogonal to the X-axis direction.
  • one return light is controlled based on the control of the relative positional relationship between the predetermined pinhole and the light receiving means (PD) on the optical axis (so-called Z-axis direction). It is possible to more precisely realize that the stray light is spatially filtered (spatial removal) by selectively passing the light.
  • another optical pickup of the present invention is an optical pickup that performs at least one of data recording and reproduction with respect to a recording medium including a plurality of recording layers, and includes laser light.
  • the optical system that guides the irradiated laser light to one recording layer of the plurality of recording layers and the guided laser light.
  • a second control means for controlling a relative positional relationship on the optical axis with respect to the pinhole, the predetermined opening, and the light receiving means, based on the received one return light, Corresponding to the data Comprising operation means you calculating the RF signal.
  • laser light emitted from a light source is emitted from a plurality of recording layers by an optical system such as an object lens, a beam splitter, or a prism. It is guided to one recording layer and condensed. At the same time, one return light reflected on one recording layer is received by the light receiving means. Therefore, the laser beam that is guided and condensed to one recording layer can reproduce information pits and marks formed on the one recording layer. Therefore, it is possible to reproduce predetermined information on the optical disc power.
  • the focused laser beam can form information pits and marks in one recording layer. Therefore, it is possible to record predetermined information on the optical disc.
  • a spatial positional relationship between the predetermined pinhole and the light receiving means (PD) (specifically, the X axis, the y axis, Or the positional relationship in the z-axis direction) is controlled. Based on the control of this positional relationship, it is possible to achieve high accuracy to selectively pass one return light and spatially filter (spatial removal) stray light. Subsequently, an RF signal corresponding to the data is calculated by the calculation means based on the one return light.
  • Another aspect of the optical pickup of the present invention includes a variable-focus lens that condenses the one return light at the predetermined opening, and the variable focus so that the one return light is emitted.
  • First control means for applying a predetermined voltage to the lens.
  • a predetermined voltage is applied to the variable focus lens so that one return light is focused at a predetermined pinhole position. Yes. Therefore, a given pinhole selectively passes one return light, that is, passes one return light at a relatively high level and spatially filters (spatially removes) stray light. Can be realized more effectively.
  • the light receiving means includes a first light receiving element for receiving the one return light
  • the first control means receives light with the first light receiving element.
  • the predetermined voltage is applied based on the returned light.
  • under the control of the first control means at least the condensing point position determined with high accuracy based on, for example, the signal level of one return light received by the first light receiving element.
  • a predetermined voltage corresponding to can be applied to the variable focus lens.
  • the light receiving means includes a first light receiving element for receiving the one return light, and the second control means receives light with the first light receiving element. Based on the returned light, the relative positional relationship between the predetermined opening and the light receiving means is controlled.
  • the second control means under the control of the second control means, at least based on, for example, the signal level of one return light received by the first light receiving element, the predetermined pinhole and the light receiving means It is possible to control the relative positional relationship with high accuracy.
  • the light receiving means is provided in the other recording layer of the plurality of recording layers due to the first light receiving element and the guided laser beam.
  • a second light receiving element for receiving the reflected stray light wherein the first light receiving element is disposed relatively close to the optical axis of the laser light, and the second light receiving element is relative to the optical axis. It may be configured to be placed far away.
  • the first light receiving element that can receive one return light more efficiently by being arranged, for example, on the inner peripheral side, and (ii), for example, the outer peripheral side
  • the effects of stray light can be quantitatively or qualitatively determined. It is possible to grasp with higher accuracy.
  • the pinhole includes a third light receiving element for receiving the one return light on an irradiation surface on which the return light is irradiated. 1
  • the control means applies the predetermined voltage based on the one return light received by the third light receiving element.
  • a predetermined voltage corresponding to can be applied to the variable focus lens.
  • the pinhole is irradiated with the return light.
  • a second light receiving element for receiving the one return light, and the second control means is configured to perform the predetermined operation based on the one return light received by the third light receiving element. The relative positional relationship between the opening and the light receiving means is controlled.
  • the second control means under the control of the second control means, based on, for example, the signal level of at least one return light received by the third light receiving element, the predetermined pinhole and the light receiving means It is possible to control the relative positional relationship with high accuracy.
  • the pinhole is formed on the irradiation surface on which the return light is irradiated due to the third light receiving element and the guided laser light.
  • At least a fourth light receiving element for receiving stray light reflected by the other recording layer, and the third light receiving element is disposed relatively close to the optical axis of the laser beam.
  • the fourth light receiving element may be arranged relatively far from the optical axis.
  • the effect of stray light can be reduced effectively and quantitatively or qualitatively. It is possible to grasp with higher accuracy.
  • Another aspect of the optical pickup of the present invention further includes calculation means for calculating an RF signal corresponding to the data based on the received one return light, and the one return light is provided.
  • An operation coefficient is calculated based on a difference between one corresponding signal component and another signal component corresponding to stray light reflected in another recording layer of the plurality of recording layers, and the calculation coefficient is Based on this, it further comprises third control means for controlling the computing means so as to compute the RF signal.
  • the influence of stray light is grasped quantitatively or qualitatively.
  • the calculation coefficient is such that the stray light component is substantially zero.
  • the shape and area of the light receiving means based on optical characteristics such as refractive index or physical characteristics such as magnetic, electrical or structural characteristics.
  • optical characteristics such as refractive index or physical characteristics such as magnetic, electrical or structural characteristics.
  • the “physical characteristic” according to the present invention may be a distance between a pinhole and a light receiving means, for example.
  • the “physical property” may be, for example, the diameter of the opening of the pinhole. Therefore, this light receiving means can receive one return light while effectively reducing the influence of stray light.
  • the light receiving means is divided into at least two parts in line symmetry or point symmetry.
  • the light receiving means for example, based on the one return light (signal level) received by the light receiving means divided into at least two parts in line symmetry or point symmetry, for example, under the control of the first control means described above.
  • the influence of stray light is reduced by a predetermined pinhole. Therefore, it is possible to improve the SZN ratio of the signal component of one return light and reproduce the data recorded on the multilayer optical disk with higher accuracy.
  • By reducing the effect of stray light it is possible to improve the SZN ratio of the signal component of one return light, and to record or reproduce data on a multilayer optical disc with higher accuracy.
  • an information device records the data by irradiating the optical disc with the above-described optical pickup of the present invention (including various aspects thereof) and the laser beam. Or recording / reproducing means for performing reproduction.
  • the light source, the optical system, the light receiving means, A predetermined pinhole, a variable focus lens, first control means, and calculation means are provided. Therefore, by reducing the influence of stray light, the SZN ratio of the signal component of one return light can be improved, and the data recorded on the multilayer optical disk can be reproduced with higher accuracy. In addition, by reducing the influence of stray light, the SZN ratio of the signal component of one return light can be improved and data can be recorded on the multilayer optical disk with higher accuracy.
  • another optical pickup of the present invention includes a light source, an optical system, a light receiving means, a predetermined pinhole, a second control means, and a calculation means. Therefore, by reducing the influence of stray light, the SZN ratio of the signal component of one return light can be improved, and the data recorded on the multilayer optical disk can be reproduced with higher accuracy. By reducing the effect of stray light, it is possible to improve the SZN ratio of the signal component of one return light and to record data on a multilayer optical disc with higher accuracy.
  • the information device of the present invention includes a light source, an optical system, a light receiving means, a predetermined pinhole, a variable focus lens, a first or second control means, a computing means, and a recording / reproducing means. Therefore, by reducing the influence of stray light, the SZN ratio of the signal component of one return light can be improved, and the data recorded on the multilayer optical disk can be reproduced with higher accuracy. In addition, by reducing the effect of stray light, the SNR ratio of the signal component of one return light can be improved, and data can be recorded on a multilayer optical disk with higher accuracy.
  • FIG. 1 is a block diagram showing a basic configuration of an information recording / reproducing apparatus and a host computer according to an embodiment of an information recording apparatus of the present invention.
  • FIG. 2 is a block diagram schematically showing a more detailed configuration of the pickup 100 in the information recording / reproducing apparatus 300 in the example.
  • FIG. 3 is a schematic diagram schematically showing a confocal optical system according to the present example.
  • FIG. 4 is a schematic diagram schematically showing one specific example of an optical element for selecting one return light according to the present embodiment.
  • FIG. 5 is a schematic diagram schematically showing another specific example of a light receiving element that receives one return light according to the present embodiment.
  • FIG. 6 is a schematic diagram schematically showing another specific example (No. 1) of the optical element for selecting one return light according to the present embodiment.
  • FIG. 7 is a schematic diagram schematically showing another specific example (No. 2) of the optical element for selecting one return light according to the present embodiment.
  • FIG. 8 is a graph schematically showing a process of calculating a desired signal component based on signal components received at the inner and outer peripheral portions of the light receiving element according to the present embodiment.
  • FIG. 9 is a schematic diagram schematically showing another specific example (No. 3) of the optical element for selecting one return light according to the present embodiment.
  • FIG. 10 is a schematic diagram schematically showing another specific example (No. 4) of the optical element for selecting one return light according to the present embodiment.
  • FIG. 11 is a block diagram schematically showing a more detailed structure of the pickup 100 in the information recording / reproducing apparatus 300 in the second example.
  • FIG. 12 is a schematic diagram schematically showing a confocal optical system according to a second example.
  • FIG. 13 is another schematic diagram schematically showing the confocal optical system according to the second example.
  • FIG. 14 is a plan view of a light receiving means according to a comparative example.
  • the present embodiment is an example in which the information recording apparatus according to the present invention is applied to an information recording / reproducing apparatus for an optical disc.
  • FIG. 1 is a block diagram showing the basic configuration of the information recording / reproducing apparatus and the host computer according to the embodiment of the information recording apparatus of the present invention.
  • the information recording / reproducing apparatus 300 has a function of recording recording data on the optical disc 100 and a function of reproducing recording data recorded on the optical disc 100.
  • the information recording / reproducing apparatus 300 is an apparatus that records information on the optical disc 100 and reads information recorded on the optical disc 100 under the control of a CPU (Central Processing Unit) 314 for driving.
  • a CPU Central Processing Unit
  • the information recording / reproducing apparatus 300 includes an optical disc 100, an optical pickup 301, a signal recording / reproducing unit 302, an address detecting unit 303, a CPU (drive control unit) 314, a spindle motor 306, a memory 307, and a data input / output control unit 308. And a bus 309.
  • the host computer 400 includes a CPU (host control means) 401, a memory 402, and operation control. Means 403, operation buttons 404, display panel 405, data input / output control means 406, and bus 407 are provided.
  • CPU host control means
  • memory main memory
  • operation control Means 403, operation buttons 404, display panel 405, data input / output control means 406, and bus 407 are provided.
  • the information recording / reproducing apparatus 300 may be configured to be communicable with an external network by housing the host computer 400 provided with communication means such as a modem in the same casing.
  • the CPU (host control means) 401 of the host computer 400 provided with communication means such as i-link directly controls the information recording / reproducing apparatus 300 via the data input / output control means 308 and the bus 309. By doing so, you may be able to communicate with an external network.
  • the optical pickup 301 performs recording / reproduction on the optical disc 100, and includes a semiconductor laser device and a lens. More specifically, the optical pickup 301 irradiates the optical disc 100 with a light beam such as a laser beam at a first power as a read light during reproduction, and modulates with a second power as a write light at the time of recording. Irradiate while letting go.
  • a light beam such as a laser beam at a first power as a read light during reproduction
  • a second power as a write light at the time of recording. Irradiate while letting go.
  • the signal recording / reproducing means 302 records or reproduces the optical disc 100 by controlling the optical pickup 301 and the spindle motor 306. More specifically, the signal recording / reproducing means 302 is constituted by, for example, a laser diode driver (LD dryer) and a head amplifier.
  • the laser diode driver drives a semiconductor laser (not shown) provided in the optical pickup 301.
  • the head amplifier amplifies the output signal of the optical pickup 301, that is, the reflected light of the light beam, and outputs the amplified signal.
  • the signal recording / reproducing means 302 determines the optimum laser power by OPC pattern recording and reproduction processing together with a timing generator (not shown) under the control of the CPU 314 during OPC (Optimum Power Control) processing.
  • a semiconductor laser (not shown) provided in the optical pickup 301 is driven so that the above can be performed.
  • the signal recording / reproducing means 302, together with the optical pickup 301 constitutes an example of the “recording / reproducing means” according to the present invention.
  • the address detection unit 303 also detects an address (address information) in the optical disc 100 for the reproduction signal power output by the signal recording / reproducing means 302, for example, including a pre-format address signal.
  • the CPU (drive control means) 314 controls the entire information recording / reproducing apparatus 300 by giving instructions to various control means via the bus 309. It should be noted that the software for operating CPU314 The software or firmware is stored in the memory 307. In particular, the CPU 314 constitutes an example of “control means” according to the present invention.
  • the spindle motor 306 rotates and stops the optical disc 100 and operates when accessing the optical disc. More specifically, the spindle motor 306 is configured to rotate and stop the optical disc 100 at a predetermined speed while receiving spindle servo from a servo unit or the like (not shown).
  • the memory 307 includes general data processing and OPC in the information recording / reproducing apparatus 300 such as a buffer area for recording / reproducing data and an area used as an intermediate buffer when converted into data used by the signal recording / reproducing means 302. Used in processing.
  • the memory 307 has a program for operating as a recorder device, that is, a ROM area in which firmware is stored, a buffer for temporarily storing recording / playback data, a variable necessary for the operation of the firmware program, and the like.
  • the RAM area to be stored is configured.
  • Data input / output control means 308 controls external data input / output to / from information recording / reproducing apparatus 300, and stores and retrieves data in / from data buffer on memory 307. Connected to the information recording / reproducing apparatus 300 via an interface such as SCSI or ATAPI!
  • the drive control command issued from the external host computer 400 (hereinafter referred to as a host as appropriate) is the data input / output control means. It is transmitted to CPU 314 via 308. Similarly, recording / reproduction data is transmitted / received to / from the host computer 400 via the data input / output control means 308.
  • the CPU (host control means) 401, the memory 402, the data input / output control means 406, and the bus 407 are substantially the same as the corresponding components in the information recording / reproducing apparatus 300. It is.
  • the operation control means 403 receives and displays an operation instruction for the host computer 400. For example, the operation control means 403 transmits an instruction by the operation button 404 to the CPU 401 for recording or reproduction. Based on the instruction information from the operation control means 403, the CPU 401 transmits a control command (command) to the information recording / reproducing apparatus 300 via the data input / output means 406 to control the entire information recording / reproducing apparatus 300. You may comprise as follows. Similarly, the CPU 401 sends a command requesting the information recording / reproducing apparatus 300 to send the operation status to the host. I can believe.
  • the CPU 401 displays the operation state of the information recording / reproducing apparatus 300 on the display panel 405 such as a fluorescent tube or LCD via the operation control means 403. Can output
  • One specific example of using the information recording / reproducing apparatus 300 and the host computer 400 in combination as described above is a household device such as a recorder device that records and reproduces video.
  • This recorder device is a device that records video signals from broadcast receiver tuners and external connection jacks on a disc, and outputs the video signals reproduced from the disc to an external display device such as a television.
  • the program stored in the memory 402 is executed by the CPU 401 to operate as a recorder device.
  • the information recording / reproducing apparatus 300 is a disk drive (hereinafter referred to as a drive as appropriate)
  • the host computer 400 is a personal computer workstation.
  • the host computer such as a personal computer and the drive are connected via SCSI / ATAPI data input / output control means 308 (406), and the application such as writing software installed in the host computer controls the disk drive. To do.
  • FIG. 2 is a block diagram schematically showing a more detailed configuration of the pickup 100 in the information recording / reproducing apparatus 300 according to the present embodiment.
  • the optical pickup 301 includes a hologram laser 101, a diffraction grating 102, a spherical aberration correction element 103, a collimator lens 104, a half mirror 105, an objective lens 108, and an actuator unit 109.
  • a driver 119 to be controlled.
  • the hologram laser 101 constitutes one specific example of the “light source” of the present invention, and a laser chip, a substrate, a light receiving element, or a hologram capable of emitting laser light LB having a plurality of wavelengths (not shown). It has elements and the like.
  • the laser chip and the light receiving element are arranged on the same substrate, and the hologram element is provided facing the laser beam LB output side of the substrate.
  • the laser chip may emit a laser beam LB corresponding to the type of the optical disc 100 having a plurality of types.
  • the hologram laser 11 may have functions as a plurality of light sources and detectors.
  • the hologram laser 101 including a laser chip and a light receiving element as a whole, a configuration including a plurality of laser chips and a plurality of light receiving elements separately may be adopted!
  • the diffraction grating 102 diffracts the laser light emitted from the hologram laser 101 into 0th-order light, + first-order diffracted light, and first-order diffracted light.
  • the spherical aberration correcting element 103 performs optimal spherical aberration correction according to the substrate thickness of the optical disc 100.
  • the collimator lens 104 converts the incident laser light LB into substantially parallel light and causes the half mirror 105 to radiate humans.
  • the half mirror 105 transmits 100% of the laser beam LB incident from the hologram laser 101 side as it is, and also reflects the laser beam LB (that is, the reflection of the laser beam LB from the optical disc 100) on which the side force of the optical disc 100 is also incident. Light) is transmitted by 90% and reflected by 10%. 10% of the reflected light reflected by the half mirror 105 is condensed on the photodetector 114 via the condenser lens 112 and the hologram element 113.
  • the aperture limiting element 106 includes, for example, a liquid crystal shirt, and the numerical aperture (NA: Numerical value) of the objective lens 108 on the laser beam LB emission side according to the substrate thickness (in other words, the type) of the optical disc 100. Let Aperture) change substantially! ,.
  • the pinhole 117 is a member that has an opening having a predetermined size, a so-called hole, and is capable of spatially filtering laser light by passing through the opening.
  • the objective lens 108 constitutes a specific example of the “optical system” of the present invention.
  • the objective lens 108 collects the incident laser beam LB and irradiates it on the recording surface of the optical disc 100.
  • the actuator unit 109 constitutes another specific example of the “optical system” of the present invention, and has a drive mechanism for changing the arrangement position of the objective lens 108. More specifically, the actuator unit 109 determines the position of the objective lens 108 in the focus direction (Z direction, FIG. Left and right direction).
  • the objective lens Z position sensor 110 is an absolute or relative position in the Z direction of the objective lens (that is, an absolute or relative position in the direction along the optical axis of the laser beam LB or in the focus direction). Further, the objective lens Z position sensor 110 outputs the measured position of the objective lens in the Z direction to a disc determination unit 314b described later.
  • the condensing lens 112 fluoresces the reflected light reflected by the half mirror 105.
  • the hologram element 113 is disposed between the condensing lens 112 and the condensing point of the reflected light collected by the condensing lens 112.
  • the hologram element 113 divides the reflected light spot formed on the hologram element 113 into a plurality of divided spot areas, and collects a part of the reflected light in each spot area in the photodetector 114. Shine.
  • the photo detector 114 constitutes a specific example of the “light receiving means” of the present invention, and receives a part of the reflected light in a plurality of spot regions collected by the hologram element 113 and transmits the light. Detect the intensity level.
  • the photodetector 114 outputs the detected light intensity level and the like to the calculation unit 314c described later.
  • the CPU 314 includes a pinhole position control unit 314a and a disk determination unit 31 therein.
  • the pinhole position control unit 314a includes the driver 119 and the pinhole 117.
  • the position in the Z-axis direction is controlled.
  • the disc determination unit 314b is configured to detect the objective lens output from the objective lens Z position sensor 110.
  • V discriminate the type (or substrate thickness) of the optical disc 100.
  • the calculation unit 314c constitutes one specific example of the “calculation means” of the present invention, and is a photo detector.
  • the amount of the signal component actually generated is calculated.
  • one return light according to the present embodiment is selectively used as a light receiving means.
  • a specific example of an optical element that receives light hereinafter, appropriately referred to as “an optical element that selects one return light” will be described.
  • FIG. 3 is a schematic diagram schematically showing the confocal optical system according to the present embodiment.
  • the optical axis direction in FIG. 3 and FIG. 4 described later is shown as the Z-axis direction.
  • the confocal position is generally different for each recording layer.
  • the “confocal position” according to the present embodiment is a laser beam irradiated, focused on one recording layer, and focused again by a reflected light collecting lens that is scattered or reflected. It is a position.
  • the condensing position and the confocal position in one recording layer may have a conjugate relationship.
  • the return light focused and scattered or reflected by the laser beam LB force L 1 layer by the actuator unit 109 and the objective lens 108 is reflected by the condenser lens 112. Again, focusing is performed at the confocal position “XI” in the Z-axis direction.
  • the laser beam LB is focused on the L2 layer by the actuator unit 109 and the objective lens 108, and the returned light that is scattered or reflected is again returned to the Z-axis direction by the condenser lens 112. Is focused at the confocal position “X2”.
  • a specific example of “one return light” according to the present invention is “return light focused on and scattered or reflected on the L1 layer” or “return light focused on and scattered or reflected on the L2 layer”. It is composed of “light”.
  • the condensing point position and the confocal position in each recording layer are generally associated one-to-one. According to this confocal optical system, it is possible to perform fine adjustment at the time of designing the optical path with higher accuracy. Therefore, it is preferable to cope with time-series changes in the confocal position.
  • FIG. 4 is a schematic diagram schematically showing one specific example of the optical element for selecting one return light according to the present embodiment.
  • the actuator unit 109 and the objective lens are controlled under the control of the CPU 314. 108, the laser beam LB is focused on the L2 layer, and the scattered or reflected return light is focused again at the confocal position “X2” in the Z-axis direction by the condenser lens 112.
  • the pin hole 117 whose position can be changed in the Z-axis direction is provided. Then, under the control of the pinhole position control unit 314a, the opening of the pinhole 117 and the confocal position “X2” can be substantially matched. It should be noted that the position of the pinhole 117 can be changed not only in the Z-axis direction but also in the X-axis direction and the Y-axis direction orthogonal to the Z-axis direction.
  • the stray light component such as the return light from the L2 layer is spatially filtered by the pinhole 117 located at the confocal position “XI”.
  • the actions that can be performed can be generally described in the same manner.
  • FIG. 5 is a schematic diagram schematically showing another specific example of the light receiving element that receives one return light according to the present embodiment.
  • a surface is a view of the pinhole as viewed from the side irradiated with the return light
  • B surface is a view of the pinhole as viewed from the light receiving element 114a side.
  • the pinhole 117 may include, for example, a light receiving region divided into four on the surface irradiated with the return light. Therefore, the return light is This return light can be received before passing through the control panel 117. As a result, compared with the case where light is received by the light receiving element 114a after passing through the return light pinhole 117, the position of the pinhole 117 is controlled based on the signal level of stray light, or by a liquid crystal lens described later. It is possible to appropriately control the focal point position.
  • the pinhole 117 may be provided with a light receiving area divided into two in an inner peripheral area and an outer peripheral area in addition to or instead of the light receiving area divided into four.
  • FIG. 6 is a schematic diagram schematically showing another specific example (No. 1) of the optical element for selecting one return light according to the present embodiment. Note that, in other specific examples (part 1), the same reference numerals are given to the configurations that are substantially the same as the configurations in the above-described specific example, and description thereof will be omitted as appropriate.
  • the laser beam LB force is focused on the L2 layer and scattered by the actuator unit 109 and the objective lens 108 under the control of the CPU 314.
  • the reflected return light is focused again at the confocal position “X2” in the Z-axis direction by the condenser lens 112.
  • the pinhole 117a whose position is fixed in the Z-axis direction and the liquid crystal lens 118 (that is, one specific example of a variable focus lens capable of changing the focal position) ).
  • the confocal position of the return light can be adjusted in the Z-axis direction by the liquid crystal lens 118, so that the opening of the pinhole 117a and the confocal position “X2” are substantially coincident. It is possible to Refer to pages 57 to 58 of Applied Physics 63rd No. 1 (1994) for the detailed mode of the liquid crystal lens (liquid crystal layer) that constitutes a specific example of the variable focus lens. Please refer to pages 59 to 62 of Applied Physics No. 63 ⁇ No. 1 (1994) for more detailed aspects of the electro-optic lens that constitutes the variable focus lens.
  • the SZN ratio of the signal component of the return light from the desired recording layer is improved by significantly reducing the influence of stray light, and the multilayer type More accurate playback or recording of data during playback or recording on an optical disc Can be realized.
  • FIG. 7 is a schematic diagram schematically showing another specific example (No. 2) of the optical element for selecting one return light according to the present embodiment.
  • FIG. 8 is a graph schematically showing a process of calculating a desired signal component based on signal components received at the inner and outer peripheral portions of the light receiving element according to the present embodiment.
  • the same reference numerals are given to the configurations that are substantially the same as the configurations in the above-described specific example, and the description thereof will be omitted as appropriate.
  • the inner peripheral part of the light receiving element 114a is selectively, that is, The return light from the L2 layer is received at a relatively high level.
  • the outer peripheral portion of the light receiving element 114a selectively receives stray light (for example, return light from the L1 layer) at a relatively high level.
  • the optical system is based on the signal component from the L2 layer corresponding to the return light from the L2 layer and the signal component from the L1 layer corresponding to the stray light from the L1 layer.
  • first light receiving element configured by the inner peripheral portion of the light receiving element 114a
  • second light receiving element configured by the outer peripheral portion of the light receiving element 114a. Let's make a concrete example of this.
  • the signal component may be at least one of an RF signal, a wobble signal, and an address signal (LPP).
  • the signal component may be a control signal for performing focus servo or tracking servo.
  • the inner periphery of the light receiving element 114a (“PD (Photo Detector) in FIG. 8” Inner circumference
  • the signal component detected at the outer periphery of the light receiving element 114a (see “PD outer periphery” in FIG. 8) is offset (subtracted) from the signal component detected at
  • PD outer periphery in FIG. 8
  • the process of offsetting this signal component is expressed as the following equation (1).
  • ⁇ is a variable coefficient.
  • the coefficient “ ⁇ ” is optimized to minimize stray light from other layer forces depending on the position change of the light receiving element in the ⁇ axis direction and the size of the pinhole. This optimization is performed on an individual basis based on experimental, theoretical, empirical, simulation, etc.
  • the signal component detected at the inner periphery of the light receiving element 114a is expressed by the following equation (2), and the signal component detected at the outer periphery of the light receiving element 114a is expressed by the following equation (3) Consider the case indicated by).
  • L2 is a signal component corresponding to the return light from the L2 layer
  • L1 is a signal component corresponding to the return light from the L1 layer.
  • the coefficient “K” is set to “2 ⁇ 5 (2/5)”, so that the following equation (la ) And the ideal signal component in the return light from the L2 layer can be calculated.
  • the ideal signal component in the return light of the L2 layer can be calculated.
  • the ideal signal component in the return light of the L1 layer can be calculated.
  • part 2 of the optical element that selects one return light according to the present embodiment in addition to significantly reducing the influence of stray light, stray light Quantitatively or qualitatively grasping the effects of noise and using them actively, it is possible to calculate the ideal signal component in the desired return light. It is possible to realize data reproduction or recording with higher accuracy.
  • an ideal signal component in the desired return light based on the degree of the influence of stray light can be calculated with higher accuracy.
  • the radius of the inner periphery of the light receiving element is relatively If the light diameter of the return light is relatively small (that is, the amount of the return light irradiated to the light receiving element is relatively small), the light receiving element You may make it make the radius of an inner peripheral part relatively small.
  • FIG. 9 is a schematic diagram schematically showing another specific example (part 3) of the optical element for selecting one return light according to the present embodiment.
  • the same reference numerals are given to the configurations substantially the same as the configuration in the above-described specific example, and the description thereof will be omitted as appropriate.
  • the confocal position of the return light from a desired recording layer such as the L2 layer is made substantially the same as that of the light receiving element 114b. It is possible to selectively receive the return light from a desired recording layer, such as a relatively high level.
  • the shape and area of the light receiving element 114b are optical characteristics or physical (magnetic or electrical) characteristics in an optical element such as the hologram element 113 and an optical system such as the condenser lens 112, for example. It is possible to specify based on this.
  • the shape and area of the light receiving element 114b can be defined based on various characteristics of the optical element and the optical system so that stray light such as return light from the L1 layer is not irradiated. It is.
  • the SZN ratio of the signal component of the return light from the desired recording layer is improved, and the multilayer light When reproducing or recording on a disk, it is possible to achieve data reproduction or recording with higher accuracy.
  • FIG. 10 is a schematic diagram schematically showing another specific example (No. 4) of the optical element for selecting one return light according to the present embodiment.
  • the same reference numerals are given to the configurations that are substantially the same as the configurations in the one specific example described above, and the description thereof will be omitted as appropriate.
  • the hologram element 113 determines the condensing point position of the signal light corresponding to the RF signal out of the return light from the desired recording layer such as the L2 layer, for example. Set to approximately the same position as 14r. Therefore, in the RF light receiving element 114r, the signal light corresponding to the RF signal out of the return light from the desired recording layer is selectively, that is, a relatively high level. Light can be received.
  • the focus position of the signal light corresponding to the focus error signal (FE signal) or tracking error signal (TE signal) out of the return light from the desired recording layer can be set as the FEZTE light receiving element 114f. , Make it almost the same position Therefore, the light receiving element 114f for FEZTE can selectively receive the signal light corresponding to the FE signal or TE signal out of the return light from the desired recording layer, that is, at a relatively high level. It is.
  • the RF light receiving element 114r is arranged at the position where the “+ 1st order light” or “first primary light” is irradiated.
  • stray light such as return light of the L1 layer force can be effectively reduced from irradiating the RF light receiving element 114r.
  • the SZN ratio of the signal component of the return light from the desired recording layer can be improved by effectively reducing the influence of stray light based on the arrangement and roles of the plurality of light receiving elements, and the multilayer When reproducing or recording on a type of optical disc, it is possible to achieve data reproduction or recording with higher accuracy.
  • FIG. 11 is a block diagram schematically showing a more detailed configuration of the pickup 100 in the information recording / reproducing apparatus 300 according to the second embodiment.
  • the optical pickup 301 includes a hologram laser 101, a diffraction grating, and the collimator lens 104 and the condenser lens 112 omitted from the above-described embodiments. 102, spherical aberration correction element 103, half mirror 105, objective lens 108, actuator unit 109, objective lens Z position sensor 110, hologram element 113, photo detector 114, and pinhole 117. . Since these components are generally the same as those in the above-described embodiment, the description thereof is omitted for convenience.
  • Figure 12 shows the confocal optical system according to the second example. It is a schematic diagram shown typically. In FIG. 12, the optical axis direction is shown as the Z-axis direction.
  • the “infinite optical system” according to the present embodiment is a general term for optical pickups in which the light beam incident on the objective lens is parallel light (collimated light). The number of parts increases.
  • the “finite optical system” according to the present embodiment is a general term for pickups in which the light beam incident on the objective lens is a divergent light, and the collimating lens for the forward path and the backward path is not necessary, but the NA of the effective objective lens Therefore, a high objective lens performance is required.
  • the confocal position is generally different for each recording layer.
  • the laser beam LB force is focused on the L2 layer by the actuator unit 109 and the objective lens 108, and the returned light force scattered or reflected by the half mirror 105 is again used in the Z-axis direction. Is focused at the confocal position “X2”.
  • the stray light from the L1 layer is also collected at the position “XI” near the light receiving element with the confocal position “X2” force.
  • a specific example of “one return light” according to the present invention is configured by “return light focused on and scattered or reflected by the L2 layer”. Further, a specific example of “stray light” according to the present invention is configured by “stray light from the L1 layer when focused on the L2 layer”.
  • FIG. 13 is another schematic diagram schematically showing the confocal optical system according to the second example.
  • the optical axis direction is shown as the Z-axis direction.
  • the laser beam LB force is focused on the L1 layer by the actuator unit 109 and the objective lens 108 under the control of the CPU314.
  • the focused, scattered or reflected return light is focused again at the confocal position “X2” in the Z-axis direction by the half mirror 105.
  • the stray light from the L2 layer is collected at the position “XI” where the confocal position “X2” force is also close to the light receiving element.
  • the body example is constituted by “return light focused on the L1 layer and scattered or reflected”.
  • a specific example of “stray light” according to the present invention is configured by “stray light from the L2 layer when focused on the L1 layer”.
  • the condensing point position and the confocal position in each recording layer are generally associated one-to-one. According to the confocal point optical system related to the finite optical system, it is possible to reduce the number of parts when designing the optical path.
  • the optical pickup and the information device according to the present invention can be used for an optical pickup that emits laser light when recording or reproducing data on, for example, an information recording medium such as a DVD. It can be used for information equipment provided with.

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Abstract

An optical pickup (100) is provided with (i) a light source for outputting laser beams; (ii) an optical system (108 or the like) for guiding the outputted laser beams to one of a plurality of recording layers; (iii) a light receiving means (114) for receiving returning beams reflected by the recording layers; (iv) a pin hole (117) having a prescribed opening section which selectively transmits a part of one returning beam reflected by one recording layer, among the returning beams, so as to be received by the light receiving means; (v) a convertible lens (118 or the like) for changing a focal position so that the one returning beam is focused on a prescribed pin hole; (vi) a first control means (314) for controlling the convertible lens by applying a prescribed voltage so as to focus the one returning beam on the prescribed pin hole; and (vii) a calculating means (314c or the like) for calculating RF signals based on the one received returning beam.

Description

明 細 書  Specification
光ピックアップ及び情報機器  Optical pickup and information equipment
技術分野  Technical field
[0001] 本発明は、例えば DVD等の情報記録媒体に対してデータの記録又は再生を行う 際にレーザ光を照射する光ピックアップ、及び当該光ピックアップを備える情報機器 の技術分野に関する。  The present invention relates to a technical field of an optical pickup that irradiates a laser beam when data is recorded or reproduced on an information recording medium such as a DVD, and an information device including the optical pickup.
背景技術  Background art
[0002] 例えば 2層型の Blu-rayや、 2層型の DVD等のように、レーザ光等を用いて光学的 に情報信号 (データ)の記録又は再生を行う、多層型の光ディスク等の情報記録媒体 が開発されている。このような多層型の光ディスクにおいては、記録層と、記録層との 間隔が広いと、球面収差の影響により選択された記録層からの信号が劣化する可能 性があるため、記録層と記録層との間隔を狭くする傾向にある。し力しながら、記録層 と記録層との間隔が狭くなると、所謂、層間クロストークにより、多層型の光ディスクか らの戻り光には、選択された所望の記録層（以下、適宜「一の記録層」と称す）におい て反射する反射光 (以下、適宜「一の戻り光」と称す)の成分だけでなぐ一の記録層 以外の他の記録層にお 、て反射する反射光（以下、適宜「迷光」と称す)の成分も、 高いレベルで含まれている。よって、例えば再生信号等の信号成分の SZN比が低 下する可能性がある。  [0002] For example, a multi-layer optical disk or the like that optically records or reproduces an information signal (data) using a laser beam or the like, such as a dual-layer Blu-ray or a dual-layer DVD. Information recording media have been developed. In such a multi-layer type optical disc, if the distance between the recording layer and the recording layer is wide, the signal from the selected recording layer may be deteriorated due to the influence of spherical aberration. It tends to narrow the interval. However, when the distance between the recording layers becomes narrow, the return light from the multi-layer optical disc is caused by so-called interlayer crosstalk, so that the desired recording layer (hereinafter referred to as “one of the appropriate ones” is selected. Reflected light (hereinafter referred to as “recording layer”) reflected by another recording layer other than one recording layer (hereinafter referred to as “one return light” where appropriate). (Also called “stray light” as appropriate) is also contained at a high level. Therefore, for example, the SZN ratio of signal components such as playback signals may be reduced.
[0003] 詳細には、多層型の光ディスクにおける一の戻り光の信号成分と、迷光の成分とは 、トレードオフの関係にあることが一般的に知られている。即ち、受光手段の受光領 域の面積を小さくした場合、迷光の成分を相対的に低いレベルにさせ、迷光の影響 を小さくすることは可能であるが、同時に、一の戻り光の信号成分も相対的に低いレ ベルになり、 SZN比も低下してしまう。他方、受光領域の面積を大きくした場合、一 の戻り光の信号成分を相対的に高いレベルにさせることは可能である力 同時に、迷 光の成分も相対的に高いレベルになり、やはり、 SZN比も低下してしまうという技術 的な問題点が生じてしまう。  In detail, it is generally known that a signal component of one return light and a stray light component in a multilayer optical disc are in a trade-off relationship. In other words, when the area of the light receiving area of the light receiving means is reduced, the stray light component can be lowered to a relatively low level to reduce the effect of stray light, but at the same time, the signal component of one return light is also reduced. The level will be relatively low and the SZN ratio will also decrease. On the other hand, when the area of the light-receiving region is increased, it is possible to bring the signal component of one return light to a relatively high level. At the same time, the stray light component also becomes a relatively high level. The technical problem will be that the ratio will also decrease.
[0004] そこで、非特許文献 1にお 、ては、 2層型のブルーレイディスク（Blu-ray Disc)の記 録又は再生の際のトラッキング方式において、ホログラム素子によって、プッシュプル 信号を信号光から分離させることで、迷光の受光素子への入射を回避するための技 術について記載されている。 [0004] Therefore, Non-Patent Document 1 describes a double-layer Blu-ray Disc. The following describes a technique for avoiding the incidence of stray light to a light receiving element by separating the push-pull signal from the signal light by a hologram element in a tracking method during recording or reproduction.
[0005] 或 、は、非特許文献 2にお 、ては、多層型の情報記録媒体の各記録層からの信号 成分に含まれる迷光の影響を低減するために、共焦点光学系において、固定したピ ンホールによって、空間的にフィルタリング (空間的に除去)する技術について記載さ れている。  [0005] Alternatively, in Non-Patent Document 2, in order to reduce the influence of stray light contained in signal components from each recording layer of a multilayer information recording medium, it is fixed in a confocal optical system. It describes a technique for spatial filtering (spatial removal) using a pinhole.
[0006] 或いは、特許文献 1においては、 2層型の光ディスクの各記録層力 の戻り光の光 軸の角度の違いを利用して、各記録層からの反射光を高精度に分離する技術につ いて記載されている。  [0006] Alternatively, in Patent Document 1, a technique for separating reflected light from each recording layer with high accuracy by utilizing the difference in the angle of the optical axis of the return light of each recording layer force of a two-layer type optical disc. It is described.
[0007] 或いは、非特許文献 3においては、例えば直交する光軸に夫々対応される、複数 の受光手段を備えた、多層型の情報記録媒体の光ピックアップにっ 、て記載されて いる。  [0007] Alternatively, Non-Patent Document 3 describes, for example, an optical pickup of a multi-layer information recording medium provided with a plurality of light receiving means respectively corresponding to orthogonal optical axes.
[0008] 特許文献 1：特開 2005— 228436号公報  [0008] Patent Document 1: Japanese Patent Laid-Open No. 2005-228436
非特許文献 1 :「2層 Blu-rayディスクに適した 1ビームトラッキング方式の開発」 松下 電器産業 (株) AVコア技術開発センター ォプトデバイスグループ 信学技報 (IEIC E Technical Report CPM2005-149 (2005-10) ) 社団法人電子情報通信学会 ρ31 - 34  Non-Patent Document 1: "Development of 1-beam tracking system suitable for double-layer Blu-ray disc" Matsushita Electric Industrial Co., Ltd. AV Core Technology Development Center Opto Device Group IEICE Technical Report CPM2005-149 ( 2005-10)) The Institute of Electronics, Information and Communication Engineers ρ31-34
非特許文献 2 :「3次元多層ビット記録型メモリ」 川田 善正 (静岡大学工学部） レー ザシンポジウム 2005  Non-Patent Document 2: "3D Multi-layer Bit Recording Memory" Yoshimasa Kawada (Faculty of Engineering, Shizuoka University) Laser Symposium 2005
非特干文献 3：「SONY Experimental ¾etup」 ISOM (International symposium on Optical Memory)講演会 2004  Non-Special Reference 3: “SONY Experimental ¾etup” ISOM (International Symposium on Optical Memory) Lecture 2004
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0009] し力しながら、上述した非特許文献 1によれば、図 14に示されるように、フォーカス エラー信号、又は、 RF信号を受光するための受光素子において、迷光（図 14中の「 Stray light」と「Transmitted beam」との重なりを参照）が入射してしまい、迷光の影響 によって、所望の記録層からの戻り光の信号成分の SZN比が低下してしまうという技 術的な問題点が生じてしまう。 However, according to Non-Patent Document 1 described above, as shown in FIG. 14, in a light receiving element for receiving a focus error signal or an RF signal, stray light (“ (See the overlap between Stray light ”and“ Transmitted beam ”), and the SZN ratio of the signal component of the return light from the desired recording layer is reduced due to stray light. There will be technical problems.
[0010] 或いは、上述した非特許文献 2によれば、共焦点光学系を含む有限光学系におい ては、記録層の位置、又は、トラッキングが行われる位置によって、ピンホールの最適 な、例えば Z軸方向の位置が変化するため、迷光の影響を適切に空間的にフィルタリ ングすることが困難となってしまうという技術的な問題点が生じてしまう。  [0010] Alternatively, according to Non-Patent Document 2 described above, in a finite optical system including a confocal optical system, an optimum pinhole, for example, Z, is selected depending on the position of the recording layer or the position where tracking is performed. Since the position in the axial direction changes, there arises a technical problem that it becomes difficult to appropriately spatially filter the influence of stray light.
[0011] 或いは、上述した特許文献 1等によれば、各種の収差を管理又は制御することが困 難であるという技術的な問題点が生じてしまう。或いは、記録層を変更した際に、受 光器、又は、戻り光を集光する集光レンズの z軸方向の位置を最適化する必要があ るという技術的な問題点が生じてしまう。  [0011] Alternatively, according to Patent Document 1 and the like described above, a technical problem arises that it is difficult to manage or control various aberrations. Alternatively, when the recording layer is changed, a technical problem arises that it is necessary to optimize the position in the z-axis direction of the light receiver or the condensing lens that collects the return light.
[0012] 本発明は、例えば上述した従来の問題点に鑑みなされたものであり、例えば多層 型の光ディスク等の情報記録媒体において、迷光の影響を低減させつつ、データを 、より高精度に再生又は記録することを可能ならしめる光ピックアップ、及びこのような 光ピックアップを備える情報機器を提供することを課題とする。  The present invention has been made in view of, for example, the conventional problems described above. For example, in an information recording medium such as a multilayer optical disk, data can be reproduced with higher accuracy while reducing the influence of stray light. Alternatively, it is an object to provide an optical pickup that enables recording and an information device including such an optical pickup.
課題を解決するための手段  Means for solving the problem
[0013] (光ピックアップ）  [0013] (Optical pickup)
上記課題を解決するために、本発明の光ピックアップは、複数の記録層を備える記 録媒体に対するデータの記録及び再生のうち少なくとも一方を行う光ピックアップで あって、レーザ光を照射する光源と、照射された前記レーザ光を、前記複数の記録 層のうちの一の記録層に導く光学系と、導かれた前記レーザ光に起因して、前記複 数の記録層においてそれぞれ反射する戻り光を、受光する受光手段と、前記戻り光 のうち少なくとも前記一の記録層において反射する一の戻り光を、選択的に通過させ 、前記受光手段に受光させる所定の開口部を有するピンホールと、前記所定の開口 部に前記一の戻り光を集光させる焦点可変レンズと、前記一の戻り光を集光させるよ うに、前記焦点可変レンズに所定の電圧を印加する第 1制御手段と、を備える。  In order to solve the above problems, an optical pickup according to the present invention is an optical pickup that performs at least one of recording and reproduction of data on a recording medium including a plurality of recording layers, and a light source that irradiates laser light; An optical system that guides the irradiated laser light to one of the plurality of recording layers, and return light that is reflected by each of the plurality of recording layers due to the guided laser light. A light receiving means for receiving light, a pinhole having a predetermined opening for selectively allowing at least one return light reflected on the one recording layer out of the return light to pass through and receiving the light receiving means, A variable-focus lens for condensing the one return light at a predetermined opening, and first control means for applying a predetermined voltage to the variable-focus lens so as to collect the one return light. Prepare.
[0014] 本発明の光ピックアップによれば、光源から照射されたレーザ光は、例えば対物レ ンズ、ビームスプリッタ、又は、プリズム等の光学系により、複数の記録層のうちの一の 記録層に導かれ、集光される。と共に、一の記録層において反射する一の戻り光は、 受光手段によって受光される。よって、一の記録層に導かれ、集光されたレーザ光は 、一の記録層に形成された情報ピットやマークを再生することが可能である。よって、 光ディスク力も所定の情報を再生することが可能である。或いは、集光されたレーザ 光は、一の記録層に情報ピットやマークを形成することが可能である。よって、光ディ スクに対して所定の情報を記録することが可能である。 [0014] According to the optical pickup of the present invention, the laser light emitted from the light source is applied to one of the plurality of recording layers by an optical system such as an objective lens, a beam splitter, or a prism. Guided and condensed. At the same time, one return light reflected on one recording layer is received by the light receiving means. Therefore, the focused laser beam guided to one recording layer is It is possible to reproduce information pits and marks formed in one recording layer. Therefore, it is possible to reproduce predetermined information with the optical disc power. Alternatively, the focused laser beam can form information pits and marks in one recording layer. Therefore, it is possible to record predetermined information on the optical disc.
[0015] 特に、本発明によれば、第 1制御手段の制御下で、焦点可変レンズに所定の電圧 が印加されることによって、一の戻り光が所定のピンホールの位置において、合焦点 している。ここに、本発明に係る「ピンホール」とは、所定の大きさを有する開口部、所 謂、穴を備え、当該開口部を通過させることで、レーザ光を空間的にフィルタリングす ることが可能な部材を意味する。従って、所定のピンホールは、一の戻り光を選択的 に通過させ、即ち、一の戻り光を相対的に高いレベルで、通過させ、迷光を空間的に フィルタリング (空間的に除去)することを、より効果的に実現可能である。ここに、本 発明に係る「一の戻り光を選択的に受光する」とは、一の戻り光の信号レベルを、他 の戻り光の信号レベルと比較して、相対的に高いレベルで受光することを意味する。 カロえて、一の戻り光、及び、他の戻り光の両方を含むことを意味するようにしてもよい 。ピンホールの開口部の大きさは、戻り光成分を最大限、含んだ大きさでも良ぐまた は信号の S/N比（Signal to Noise Ratio)が一番良好な大きさにしても良いものとし、利 用方法により任意に選択可能にしても良い。続いて、例えば、演算手段によって、一 の戻り光に基づいて、データに対応される RF信号が演算される。  [0015] In particular, according to the present invention, a predetermined voltage is applied to the variable focus lens under the control of the first control means, so that one return light is focused at a predetermined pinhole position. ing. Here, the “pinhole” according to the present invention includes an opening having a predetermined size, that is, a so-called hole, and spatially filters the laser light by passing through the opening. Means a possible member. Therefore, a given pinhole selectively passes one return light, that is, passes one return light at a relatively high level and spatially filters (spatially removes) stray light. Can be realized more effectively. Here, “selectively receiving one return light” according to the present invention means that the signal level of one return light is received at a relatively high level compared to the signal level of the other return light. It means to do. It may mean that it includes both one return light and the other return light. The size of the pinhole opening may be as large as possible including the return light component, or the signal to noise ratio (Signal to Noise Ratio) may be the best. It may be arbitrarily selectable depending on the usage method. Subsequently, for example, an RF signal corresponding to the data is calculated based on one return light by the calculation means.
[0016] 詳細には、所定のピンホールの開口部において、一の戻り光が合焦点した場合、こ の集光点位置では、一の戻り光の成分を最大限、含んだ戻り光だけが選択的に、こ の所定のピンホールの開口部を通過することができる。他方で、この場合、迷光は、 合焦点していないので、所定のピンホールの位置において、迷光の光束の光径が大 きくなつている。よって、迷光はピンホールの位置で拡がってしまうので、この所定の ピンホールの開口部を通過することができないので、迷光の成分を最大限、空間的 にフィルタリングすることが可能である。  Specifically, when one return light is focused at an opening of a predetermined pinhole, at this condensing point position, only the return light including the maximum amount of one return light component is present. Optionally, it can pass through this predetermined pinhole opening. On the other hand, in this case, since the stray light is not focused, the light diameter of the stray light beam is increased at a predetermined pinhole position. Therefore, since the stray light spreads at the position of the pinhole and cannot pass through the opening of the predetermined pinhole, the stray light component can be spatially filtered to the maximum extent.
[0017] この結果、迷光の影響を低減させることで、一の戻り光の信号成分の SZN比を向 上させ、多層型の光ディスクに記録されたデータを、より高精度に再生することが可 能である。加えて、迷光の影響を低減させることで、一の戻り光の信号成分の SZN 比を向上させ、多層型の光ディスクにデータを、より高精度に記録することが可能で ある。 As a result, by reducing the influence of stray light, it is possible to improve the SZN ratio of the signal component of one return light and to reproduce the data recorded on the multilayer optical disc with higher accuracy. Noh. In addition, by reducing the effect of stray light, the SZN of the signal component of one return light The ratio can be improved and data can be recorded on the multilayer optical disk with higher accuracy.
[0018] 本発明の光ピックアップの一態様は、前記所定の開口部と、前記受光手段との相 対的な位置関係を制御する第 2制御手段を更に備える。  [0018] One aspect of the optical pickup of the present invention further includes second control means for controlling a relative positional relationship between the predetermined opening and the light receiving means.
[0019] この態様によれば、所定のピンホールと、受光手段 (PD)との、例えば、空間的な位 置関係（具体的には、 X軸、 y軸、又は z軸方向における位置関係）を制御する第 2制 御手段による位置関係の制御に基づいて、一の戻り光を選択的に通過させ、迷光を 空間的にフィルタリング (空間的に除去)することを、高精度に実現可能である。  [0019] According to this aspect, for example, a spatial positional relationship between the predetermined pinhole and the light receiving means (PD) (specifically, a positional relationship in the X-axis, y-axis, or z-axis direction) Based on the control of the positional relationship by the second control means that controls ()), it is possible to selectively pass one return light and spatially filter (remove spatially) stray light with high accuracy. It is.
[0020] 上述した第 2制御手段に係る態様は、前記第 2制御手段は、光軸方向である Z軸方 向、前記 Z軸方向と直交する X軸方向、並びに、前記 Z軸方向及び前記 X軸方向と直 交する Y軸方向に基づ 、て、前記相対的な位置関係を制御するように構成してもよ い。  [0020] In the aspect according to the second control means described above, the second control means includes a Z-axis direction that is an optical axis direction, an X-axis direction orthogonal to the Z-axis direction, and the Z-axis direction and the Z-axis direction. The relative positional relationship may be controlled based on the Y-axis direction that is orthogonal to the X-axis direction.
[0021] このように構成すれば、所定のピンホールと、受光手段 (PD)との光軸上 (所謂、 Z 軸方向）での相対的な位置関係の制御に基づいて、一の戻り光を選択的に通過させ 、迷光を空間的にフィルタリング (空間的に除去)することを、より高精度に実現可能 である。  With this configuration, one return light is controlled based on the control of the relative positional relationship between the predetermined pinhole and the light receiving means (PD) on the optical axis (so-called Z-axis direction). It is possible to more precisely realize that the stray light is spatially filtered (spatial removal) by selectively passing the light.
[0022] 上記課題を解決するために、本発明の他の光ピックアップは、複数の記録層を備え る記録媒体に対するデータの記録及び再生のうち少なくとも一方を行う光ピックアツ プであって、レーザ光を照射する光源と、照射された前記レーザ光を、前記複数の記 録層のうちの一の記録層に導く光学系と、導かれた前記レーザ光に起因して、前記 複数の記録層においてそれぞれ反射する戻り光を、受光する受光手段と、前記戻り 光のうち少なくとも前記一の記録層において反射する一の戻り光を、選択的に通過さ せ、前記受光手段に受光させる所定の開口部を有するピンホールと、前記所定の開 口部と、前記受光手段との光軸上での相対的な位置関係を制御する第 2制御手段と 、受光された前記一の戻り光に基づいて、前記データに対応される RF信号を演算す る演算手段と、を備える。  In order to solve the above problems, another optical pickup of the present invention is an optical pickup that performs at least one of data recording and reproduction with respect to a recording medium including a plurality of recording layers, and includes laser light. In the plurality of recording layers, the optical system that guides the irradiated laser light to one recording layer of the plurality of recording layers and the guided laser light. Receiving means for receiving the return light reflected respectively, and a predetermined opening for selectively allowing at least one return light reflected on at least one of the return lights to be reflected by the light receiving means. A second control means for controlling a relative positional relationship on the optical axis with respect to the pinhole, the predetermined opening, and the light receiving means, based on the received one return light, Corresponding to the data Comprising operation means you calculating the RF signal.
[0023] 本発明の他の光ピックアップによれば、光源から照射されたレーザ光は、例えば対 物レンズ、ビームスプリッタ、又は、プリズム等の光学系により、複数の記録層のうちの 一の記録層に導かれ、集光される。と共に、一の記録層において反射する一の戻り 光は、受光手段によって受光される。よって、一の記録層に導かれ、集光されたレー ザ光は、一の記録層に形成された情報ピットやマークを再生することが可能である。 よって、光ディスク力 所定の情報を再生することが可能である。或いは、集光された レーザ光は、一の記録層に情報ピットやマークを形成することが可能である。よって、 光ディスクに対して所定の情報を記録することが可能である。 [0023] According to another optical pickup of the present invention, laser light emitted from a light source is emitted from a plurality of recording layers by an optical system such as an object lens, a beam splitter, or a prism. It is guided to one recording layer and condensed. At the same time, one return light reflected on one recording layer is received by the light receiving means. Therefore, the laser beam that is guided and condensed to one recording layer can reproduce information pits and marks formed on the one recording layer. Therefore, it is possible to reproduce predetermined information on the optical disc power. Alternatively, the focused laser beam can form information pits and marks in one recording layer. Therefore, it is possible to record predetermined information on the optical disc.
[0024] 特に、本発明によれば、第 2制御手段によって、所定のピンホールと、受光手段 (P D)との、例えば、空間的な位置関係（具体的には、 X軸、 y軸、又は z軸方向における 位置関係）が制御される。この位置関係の制御に基づいて、一の戻り光を選択的に 通過させ、迷光を空間的にフィルタリング (空間的に除去)することを、高精度に実現 可能である。続いて、演算手段によって、一の戻り光に基づいて、データに対応され る RF信号が演算される。  [0024] In particular, according to the present invention, for example, a spatial positional relationship between the predetermined pinhole and the light receiving means (PD) (specifically, the X axis, the y axis, Or the positional relationship in the z-axis direction) is controlled. Based on the control of this positional relationship, it is possible to achieve high accuracy to selectively pass one return light and spatially filter (spatial removal) stray light. Subsequently, an RF signal corresponding to the data is calculated by the calculation means based on the one return light.
[0025] この結果、迷光の影響を低減させることで、一の戻り光の信号成分の SZN比を向 上させ、多層型の光ディスクに記録されたデータを、より高精度に再生することが可 能である。加えて、迷光の影響を低減させることで、一の戻り光の信号成分の SZN 比を向上させ、多層型の光ディスクにデータを、より高精度に記録することが可能で ある。  As a result, by reducing the influence of stray light, it is possible to improve the SZN ratio of the signal component of one return light and to reproduce the data recorded on the multilayer optical disk with higher accuracy. Noh. In addition, by reducing the influence of stray light, it is possible to improve the SZN ratio of the signal component of one return light and to record data on a multilayer optical disk with higher accuracy.
[0026] 本発明の他の光ピックアップの一態様は、前記所定の開口部に前記一の戻り光を 集光させる焦点可変レンズと、前記一の戻り光^^光させるように、前記焦点可変レ ンズに所定の電圧を印加する第 1制御手段と、を更に備える。  [0026] Another aspect of the optical pickup of the present invention includes a variable-focus lens that condenses the one return light at the predetermined opening, and the variable focus so that the one return light is emitted. First control means for applying a predetermined voltage to the lens.
[0027] この態様によれば、第 1制御手段の制御下で、焦点可変レンズに所定の電圧が印 カロされることによって、一の戻り光が所定のピンホールの位置において、合焦点して いる。従って、所定のピンホールは、一の戻り光を選択的に通過させ、即ち、一の戻り 光を相対的に高いレベルで、通過させ、迷光を空間的にフィルタリング (空間的に除 去)することを、より効果的に実現可能である。  [0027] According to this aspect, under the control of the first control means, a predetermined voltage is applied to the variable focus lens so that one return light is focused at a predetermined pinhole position. Yes. Therefore, a given pinhole selectively passes one return light, that is, passes one return light at a relatively high level and spatially filters (spatially removes) stray light. Can be realized more effectively.
[0028] 本発明の光ピックアップの他の態様は、前記受光手段は、前記一の戻り光を受光 するための第 1受光素子を含み、前記第 1制御手段は、前記第 1受光素子で受光さ れた前記一の戻り光に基づいて、前記所定の電圧を印加する。 [0029] この態様によれば、第 1制御手段の制御下で、少なくとも、第 1受光素子で受光され た一の戻り光の例えば信号レベルに基づいて、高精度に決定された集光点位置に 対応される所定の電圧を、焦点可変レンズに印加することが可能である。 [0028] In another aspect of the optical pickup of the present invention, the light receiving means includes a first light receiving element for receiving the one return light, and the first control means receives light with the first light receiving element. The predetermined voltage is applied based on the returned light. [0029] According to this aspect, under the control of the first control means, at least the condensing point position determined with high accuracy based on, for example, the signal level of one return light received by the first light receiving element. A predetermined voltage corresponding to can be applied to the variable focus lens.
[0030] 本発明の光ピックアップの他の態様は、前記受光手段は、前記一の戻り光を受光 するための第 1受光素子を含み、前記第 2制御手段は、前記第 1受光素子で受光さ れた前記一の戻り光に基づいて、前記所定の開口部と、前記受光手段との相対的な 位置関係を制御する。  [0030] In another aspect of the optical pickup of the present invention, the light receiving means includes a first light receiving element for receiving the one return light, and the second control means receives light with the first light receiving element. Based on the returned light, the relative positional relationship between the predetermined opening and the light receiving means is controlled.
[0031] この態様によれば、第 2制御手段の制御下で、少なくとも、第 1受光素子で受光され た一の戻り光の例えば信号レベルに基づいて、所定のピンホールと、受光手段との 相対的な位置関係を高精度に制御することが可能である。  [0031] According to this aspect, under the control of the second control means, at least based on, for example, the signal level of one return light received by the first light receiving element, the predetermined pinhole and the light receiving means It is possible to control the relative positional relationship with high accuracy.
[0032] 上述した第 1受光素子に係る態様は、前記受光手段は、前記第 1受光素子、及び 導かれた前記レーザ光に起因して、前記複数の記録層のうちの他の記録層におい て反射する迷光を受光するための第 2受光素子を含み、前記第 1受光素子は、前記 レーザ光の光軸から相対的に近くに配置され、前記第 2受光素子は、前記光軸から 相対的に遠くに配置されるように構成してもよ 、。  [0032] In the aspect related to the first light receiving element described above, the light receiving means is provided in the other recording layer of the plurality of recording layers due to the first light receiving element and the guided laser beam. A second light receiving element for receiving the reflected stray light, wherein the first light receiving element is disposed relatively close to the optical axis of the laser light, and the second light receiving element is relative to the optical axis. It may be configured to be placed far away.
[0033] このように構成すれば、（i)例えば内周側に配置されることで、一の戻り光をより効 率的に受光可能な第 1受光素子、及び、（ii)例えば外周側に配置されることで、迷光 をより効率的に受光可能な第 2受光素子に基づいて、迷光の影響を顕著に効果的に 低減させることに加えて、迷光の影響を定量的又は定性的に、より高精度に把握す ることが可能である。  With this configuration, (i) the first light receiving element that can receive one return light more efficiently by being arranged, for example, on the inner peripheral side, and (ii), for example, the outer peripheral side In addition to significantly reducing the effects of stray light based on the second light-receiving element that can receive stray light more efficiently, the effects of stray light can be quantitatively or qualitatively determined. It is possible to grasp with higher accuracy.
[0034] 本発明の光ピックアップの他の態様は、前記ピンホールは、前記戻り光が照射され る照射面において、前記一の戻り光を受光するための第 3受光素子を有し、前記第 1 制御手段は、前記第 3受光素子で受光された前記一の戻り光に基づいて、前記所定 の電圧を印加する。  [0034] In another aspect of the optical pickup of the present invention, the pinhole includes a third light receiving element for receiving the one return light on an irradiation surface on which the return light is irradiated. 1 The control means applies the predetermined voltage based on the one return light received by the third light receiving element.
[0035] この態様によれば、第 1制御手段の制御下で、少なくとも、第 3受光素子で受光され た一の戻り光の例えば信号レベルに基づいて、高精度に決定された集光点位置に 対応される所定の電圧を、焦点可変レンズに印加することが可能である。  [0035] According to this aspect, under the control of the first control means, at least the condensing point position determined with high accuracy based on, for example, the signal level of the one return light received by the third light receiving element. A predetermined voltage corresponding to can be applied to the variable focus lens.
[0036] 本発明の光ピックアップの他の態様は、前記ピンホールは、前記戻り光が照射され る照射面において、前記一の戻り光を受光するための第 3受光素子を有し、 前記第 2制御手段は、前記第 3受光素子で受光された前記一の戻り光に基づいて 、前記所定の開口部と、前記受光手段との相対的な位置関係を制御する。 In another aspect of the optical pickup of the present invention, the pinhole is irradiated with the return light. A second light receiving element for receiving the one return light, and the second control means is configured to perform the predetermined operation based on the one return light received by the third light receiving element. The relative positional relationship between the opening and the light receiving means is controlled.
[0037] この態様によれば、第 2制御手段の制御下で、少なくとも、第 3受光素子で受光され た一の戻り光の例えば信号レベルに基づいて、所定のピンホールと、受光手段との 相対的な位置関係を高精度に制御することが可能である。  [0037] According to this aspect, under the control of the second control means, based on, for example, the signal level of at least one return light received by the third light receiving element, the predetermined pinhole and the light receiving means It is possible to control the relative positional relationship with high accuracy.
[0038] 上述した第 3受光手段に係る態様は、前記ピンホールは、前記戻り光が照射される 照射面において、前記第 3受光素子、及び導かれた前記レーザ光に起因して、前記 複数の記録層のうちの他の記録層において反射する迷光を受光するための第 4受 光素子を少なくとも有し、前記第 3受光素子は、前記レーザ光の光軸から相対的に近 くに配置され、前記第 4受光素子は、前記光軸から相対的に遠くに配置されるように 構成してちょい。  [0038] In the aspect according to the third light receiving means described above, the pinhole is formed on the irradiation surface on which the return light is irradiated due to the third light receiving element and the guided laser light. At least a fourth light receiving element for receiving stray light reflected by the other recording layer, and the third light receiving element is disposed relatively close to the optical axis of the laser beam. The fourth light receiving element may be arranged relatively far from the optical axis.
[0039] このように構成すれば、（i)例えば内周側に配置されることで、一の戻り光をより効 率的に受光可能な第 3受光素子、及び、（ii)例えば外周側に配置されることで、迷光 をより効率的に受光可能な第 4受光素子に基づいて、迷光の影響を顕著に効果的に 低減させることに加えて、迷光の影響を定量的又は定性的に、より高精度に把握す ることが可能である。  [0039] With this configuration, (i) the third light receiving element that can receive one return light more efficiently by being arranged, for example, on the inner peripheral side, and (ii), for example, the outer peripheral side Based on the fourth light receiving element that can receive stray light more efficiently, the effect of stray light can be reduced effectively and quantitatively or qualitatively. It is possible to grasp with higher accuracy.
[0040] 本発明の光ピックアップの他の態様は、受光された前記一の戻り光に基づいて、前 記データに対応される RF信号を演算する演算手段を更に備え、前記一の戻り光に 対応される一の信号成分と、前記複数の記録層のうちの他の記録層において反射 する迷光に対応される他の信号成分との差分に基づいて、演算係数を算出し、前記 演算係数に基づいて、前記 RF信号を演算するように、前記演算手段を制御する第 3 制御手段を更に備える。  [0040] Another aspect of the optical pickup of the present invention further includes calculation means for calculating an RF signal corresponding to the data based on the received one return light, and the one return light is provided. An operation coefficient is calculated based on a difference between one corresponding signal component and another signal component corresponding to stray light reflected in another recording layer of the plurality of recording layers, and the calculation coefficient is Based on this, it further comprises third control means for controlling the computing means so as to compute the RF signal.
[0041] この態様によれば、迷光の影響を顕著に低減させることに加えて、迷光の影響を定 量的又は定性的に把握し、例えば、迷光成分が概略ゼロとなるような演算係数に基 づいた、所定の演算を施すことで、一の戻り光 (所望とする戻り光）における理想的な 信号成分を算出可能であり、多層型の光ディスクに対する再生又は記録の際に、デ ータの再生又は記録を、より高精度に実現することが可能である。 [0042] 本発明の光ピックアップの他の態様は、前記受光手段の形状及び面積は、前記光 学系、又は前記所定の開口部における光学的な特性、又は物理的な特性に基づい て規定される。 [0041] According to this aspect, in addition to significantly reducing the influence of stray light, the influence of stray light is grasped quantitatively or qualitatively. For example, the calculation coefficient is such that the stray light component is substantially zero. By performing a predetermined calculation based on the above, it is possible to calculate an ideal signal component in one return light (desired return light), and when reproducing or recording data on a multilayer optical disk, Can be reproduced or recorded with higher accuracy. [0042] In another aspect of the optical pickup of the present invention, the shape and area of the light receiving means are defined based on optical characteristics or physical characteristics of the optical system or the predetermined opening. The
[0043] この態様によれば、例えば屈折率等の光学的な特性、又は、例えば磁気的、電気 的又は構造的な特性等の物理的な特性に基づ 、て、受光手段の形状及び面積が 規定される。特に、本発明に係る「物理的な特性」とは、例えばピンホールと、受光手 段との距離であるようにしてもよい。或いは、この「物理的な特性」とは、例えばピンホ ールの開口部の直径であるようにしてもよい。従って、この受光手段によって、迷光の 影響を効果的に低減させつつ、一の戻り光を受光することが可能である。  [0043] According to this aspect, the shape and area of the light receiving means based on optical characteristics such as refractive index or physical characteristics such as magnetic, electrical or structural characteristics. Is defined. In particular, the “physical characteristic” according to the present invention may be a distance between a pinhole and a light receiving means, for example. Alternatively, the “physical property” may be, for example, the diameter of the opening of the pinhole. Therefore, this light receiving means can receive one return light while effectively reducing the influence of stray light.
[0044] 本発明の光ピックアップの他の態様は、前記受光手段は、線対称又は点対称に、 少なくとも 2分割されて 、る。  [0044] In another aspect of the optical pickup of the present invention, the light receiving means is divided into at least two parts in line symmetry or point symmetry.
[0045] この態様によれば、線対称又は点対称に、少なくとも 2分割された受光手段に受光 された一の戻り光（の信号レベル）に基づいた、例えば上述した第 1制御手段の制御 下で、所定のピンホールによって、迷光の影響を低減される。従って、一の戻り光の 信号成分の SZN比を向上させ、多層型の光ディスクに記録されたデータを、より高 精度に再生することが可能である。カロえて、迷光の影響を低減させることで、一の戻り 光の信号成分の SZN比を向上させ、多層型の光ディスクにデータを、より高精度に 記録又は再生することが可能である。  [0045] According to this aspect, for example, based on the one return light (signal level) received by the light receiving means divided into at least two parts in line symmetry or point symmetry, for example, under the control of the first control means described above. Thus, the influence of stray light is reduced by a predetermined pinhole. Therefore, it is possible to improve the SZN ratio of the signal component of one return light and reproduce the data recorded on the multilayer optical disk with higher accuracy. By reducing the effect of stray light, it is possible to improve the SZN ratio of the signal component of one return light, and to record or reproduce data on a multilayer optical disc with higher accuracy.
[0046] (情報機器）  [0046] (Information equipment)
上記課題を解決するために、本発明の情報機器は、上述した本発明の光ピックアツ プ (但し、その各種態様を含む）と、前記レーザ光を前記光ディスクに照射することで 、前記データの記録又は再生を行う記録再生手段とを備える。  In order to solve the above-described problems, an information device according to the present invention records the data by irradiating the optical disc with the above-described optical pickup of the present invention (including various aspects thereof) and the laser beam. Or recording / reproducing means for performing reproduction.
[0047] 本発明の情報機器によれば、上述した本発明の光ピックアップが有する各種利益 と同様の利益を享受しながら、光ディスクに対してデータを記録し、又は光ディスクに 記録されたデータを再生することができる。  [0047] According to the information device of the present invention, while enjoying the same benefits as the various advantages of the optical pickup of the present invention described above, data is recorded on the optical disc, or data recorded on the optical disc is reproduced. can do.
[0048] 本発明のこのような作用及び他の利得は次に説明する実施例から更に明らかにさ れる。  [0048] These effects and other advantages of the present invention will become more apparent from the embodiments described below.
[0049] 以上説明したように、本発明の光ピックアップによれば、光源、光学系、受光手段、 所定のピンホール、焦点可変レンズ、第 1制御手段、及び演算手段を備える。従って 、迷光の影響を低減させることで、一の戻り光の信号成分の SZN比を向上させ、多 層型の光ディスクに記録されたデータを、より高精度に再生することが可能である。加 えて、迷光の影響を低減させることで、一の戻り光の信号成分の SZN比を向上させ 、多層型の光ディスクにデータを、より高精度に記録することが可能である。 [0049] As described above, according to the optical pickup of the present invention, the light source, the optical system, the light receiving means, A predetermined pinhole, a variable focus lens, first control means, and calculation means are provided. Therefore, by reducing the influence of stray light, the SZN ratio of the signal component of one return light can be improved, and the data recorded on the multilayer optical disk can be reproduced with higher accuracy. In addition, by reducing the influence of stray light, the SZN ratio of the signal component of one return light can be improved and data can be recorded on the multilayer optical disk with higher accuracy.
[0050] 以上説明したように、本発明の他の光ピックアップによれば、光源、光学系、受光手 段、所定のピンホール、第 2制御手段、及び演算手段を備える。従って、迷光の影響 を低減させることで、一の戻り光の信号成分の SZN比を向上させ、多層型の光ディ スクに記録されたデータを、より高精度に再生することが可能である。カロえて、迷光の 影響を低減させることで、一の戻り光の信号成分の SZN比を向上させ、多層型の光 ディスクにデータを、より高精度に記録することが可能である。  [0050] As described above, another optical pickup of the present invention includes a light source, an optical system, a light receiving means, a predetermined pinhole, a second control means, and a calculation means. Therefore, by reducing the influence of stray light, the SZN ratio of the signal component of one return light can be improved, and the data recorded on the multilayer optical disk can be reproduced with higher accuracy. By reducing the effect of stray light, it is possible to improve the SZN ratio of the signal component of one return light and to record data on a multilayer optical disc with higher accuracy.
[0051] 或いは、本発明の情報機器によれば、光源、光学系、受光手段、所定のピンホー ル、焦点可変レンズ、第 1若しくは第 2制御手段、演算手段、及び、記録再生手段を 備える。従って、迷光の影響を低減させることで、一の戻り光の信号成分の SZN比 を向上させ、多層型の光ディスクに記録されたデータを、より高精度に再生することが 可能である。加えて、迷光の影響を低減させることで、一の戻り光の信号成分の SZ N比を向上させ、多層型の光ディスクにデータを、より高精度に記録することが可能 である。  [0051] Alternatively, the information device of the present invention includes a light source, an optical system, a light receiving means, a predetermined pinhole, a variable focus lens, a first or second control means, a computing means, and a recording / reproducing means. Therefore, by reducing the influence of stray light, the SZN ratio of the signal component of one return light can be improved, and the data recorded on the multilayer optical disk can be reproduced with higher accuracy. In addition, by reducing the effect of stray light, the SNR ratio of the signal component of one return light can be improved, and data can be recorded on a multilayer optical disk with higher accuracy.
図面の簡単な説明  Brief Description of Drawings
[0052] [図 1]本発明の情報記録装置の実施例に係る情報記録再生装置、及び、ホストコンビ ユータの基本構成を示したブロック図である。  FIG. 1 is a block diagram showing a basic configuration of an information recording / reproducing apparatus and a host computer according to an embodiment of an information recording apparatus of the present invention.
[図 2]本実施例に係る情報記録再生装置 300のうち特にピックアップ 100のより詳細 な構成を概略的に示すブロック図である。  FIG. 2 is a block diagram schematically showing a more detailed configuration of the pickup 100 in the information recording / reproducing apparatus 300 in the example.
[図 3]本実施例に係る共焦点光学系を図式的に示す模式図である。  FIG. 3 is a schematic diagram schematically showing a confocal optical system according to the present example.
[図 4]本実施例に係る、一の戻り光を選択する光学素子の一具体例を図式的に示す 模式図である。  FIG. 4 is a schematic diagram schematically showing one specific example of an optical element for selecting one return light according to the present embodiment.
[図 5]本実施例に係る、一の戻り光を受光する受光素子の他の具体例を図式的に示 す模式図である。 [図 6]本実施例に係る、一の戻り光を選択する光学素子の他の具体例 (その 1)を図 式的に示す模式図である。 FIG. 5 is a schematic diagram schematically showing another specific example of a light receiving element that receives one return light according to the present embodiment. FIG. 6 is a schematic diagram schematically showing another specific example (No. 1) of the optical element for selecting one return light according to the present embodiment.
[図 7]本実施例に係る、一の戻り光を選択する光学素子の他の具体例 (その 2)を図 式的に示す模式図である。  FIG. 7 is a schematic diagram schematically showing another specific example (No. 2) of the optical element for selecting one return light according to the present embodiment.
[図 8]本実施例に係る、受光素子の内周部及び外周部において受光された信号成 分に基づいて、所望となる信号成分を算出する過程を図式的に示すグラフである。  FIG. 8 is a graph schematically showing a process of calculating a desired signal component based on signal components received at the inner and outer peripheral portions of the light receiving element according to the present embodiment.
[図 9]本実施例に係る、一の戻り光を選択する光学素子の他の具体例 (その 3)を図 式的に示す模式図である。 FIG. 9 is a schematic diagram schematically showing another specific example (No. 3) of the optical element for selecting one return light according to the present embodiment.
[図 10]本実施例に係る、一の戻り光を選択する光学素子の他の具体例 (その 4)を図 式的に示す模式図である。  FIG. 10 is a schematic diagram schematically showing another specific example (No. 4) of the optical element for selecting one return light according to the present embodiment.
[図 11]第 2実施例に係る情報記録再生装置 300のうち特にピックアップ 100のより詳 細な構成を概略的に示すブロック図である。  FIG. 11 is a block diagram schematically showing a more detailed structure of the pickup 100 in the information recording / reproducing apparatus 300 in the second example.
[図 12]第 2実施例に係る共焦点光学系を図式的に示す模式図である。  FIG. 12 is a schematic diagram schematically showing a confocal optical system according to a second example.
[図 13]第 2実施例に係る共焦点光学系を図式的に示す他の模式図である。 FIG. 13 is another schematic diagram schematically showing the confocal optical system according to the second example.
[図 14]比較例に係る受光手段の平面図である。 FIG. 14 is a plan view of a light receiving means according to a comparative example.
符号の説明 Explanation of symbols
10 光ディスク  10 Optical disc
100 光ピックアップ  100 optical pickup
101 ホログラムレーザ  101 hologram laser
102 液晶 λ Ζ2板  102 LCD λ Ζ2 plates
103 球面収差補正素子  103 Spherical aberration correction element
104 コリメータレンズ  104 Collimator lens
108 対物レンズ  108 Objective lens
109 ァクチユエータ部  109 Actuator
110 対物レンズ Ζ位置センサ  110 Objective lens Ζ Position sensor
113 ホログラム素子  113 Hologram element
114 フォトディテクタ  114 photodetector
117 (又は 117a) ピンホール 300 情報記録再生装置 117 (or 117a) pinhole 300 Information recording and playback device
302 信号記録再生手段  302 Signal recording and playback means
314 CPU  314 CPU
314a ピンホール位置制御部  314a Pinhole position controller
314b ディスク判別部  314b Disc discriminator
314c 演算部  314c Operation unit
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0054] 以下、本発明を実施するための最良の形態について実施例毎に順に図面に基づ いて説明する。  Hereinafter, the best mode for carrying out the present invention will be described in each embodiment in order with reference to the drawings.
[0055] (1)情報記録再生装置の実施例  (1) Embodiment of information recording / reproducing apparatus
先ず、図 1を参照して、本発明の情報記録装置の実施例の構成及び動作について 詳細に説明する。特に、本実施例は、本発明に係る情報記録装置を光ディスク用の 情報記録再生装置に適用した例である。  First, the configuration and operation of an embodiment of the information recording apparatus of the present invention will be described in detail with reference to FIG. In particular, the present embodiment is an example in which the information recording apparatus according to the present invention is applied to an information recording / reproducing apparatus for an optical disc.
[0056] (1 1)基本構成  [0056] (1 1) Basic configuration
先ず、図 1を参照して、本発明の情報記録装置に係る実施例における情報記録再 生装置 300及び、ホストコンピュータ 400の基本構成について説明する。ここに、図 1 は、本発明の情報記録装置の実施例に係る情報記録再生装置、及び、ホストコンビ ユータの基本構成を示したブロック図である。尚、情報記録再生装置 300は、光ディ スク 100に記録データを記録する機能と、光ディスク 100に記録された記録データを 再生する機能とを備える。  First, the basic configuration of the information recording / reproducing apparatus 300 and the host computer 400 in the embodiment of the information recording apparatus of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing the basic configuration of the information recording / reproducing apparatus and the host computer according to the embodiment of the information recording apparatus of the present invention. The information recording / reproducing apparatus 300 has a function of recording recording data on the optical disc 100 and a function of reproducing recording data recorded on the optical disc 100.
[0057] 図 1を参照して情報記録再生装置 300の内部構成を説明する。情報記録再生装置 300は、ドライブ用の CPU (Central Processing Unit) 314の制御下で、光ディスク 10 0に情報を記録すると共に、光ディスク 100に記録された情報を読み取る装置である  The internal configuration of the information recording / reproducing apparatus 300 will be described with reference to FIG. The information recording / reproducing apparatus 300 is an apparatus that records information on the optical disc 100 and reads information recorded on the optical disc 100 under the control of a CPU (Central Processing Unit) 314 for driving.
[0058] 情報記録再生装置 300は、光ディスク 100、光ピックアップ 301、信号記録再生手 段 302、アドレス検出部 303、 CPU (ドライブ制御手段） 314、スピンドルモータ 306、 メモリ 307、データ入出力制御手段 308、及びバス 309を備えて構成されている。 The information recording / reproducing apparatus 300 includes an optical disc 100, an optical pickup 301, a signal recording / reproducing unit 302, an address detecting unit 303, a CPU (drive control unit) 314, a spindle motor 306, a memory 307, and a data input / output control unit 308. And a bus 309.
[0059] また、ホストコンピュータ 400は、 CPU (ホスト制御手段） 401、メモリ 402、操作制御 手段 403、操作ボタン 404、表示パネル 405、データ入出力制御手段 406、及びバ ス 407を備えて構成される。 [0059] The host computer 400 includes a CPU (host control means) 401, a memory 402, and operation control. Means 403, operation buttons 404, display panel 405, data input / output control means 406, and bus 407 are provided.
[0060] 特に、情報記録再生装置 300は、例えばモデム等の通信手段を備えたホストコンビ ユータ 400を同一筐体内に収めることにより、外部ネットワークと通信可能となるように 構成してもよい。或いは、例えば i— link等の通信手段を備えたホストコンピュータ 40 0の CPU (ホスト制御手段) 401が、データ入出力制御手段 308、及びバス 309を介 して、直接情報記録再生装置 300を制御することによって、外部ネットワークと通信 可能となるように構成してもよ 、。  [0060] In particular, the information recording / reproducing apparatus 300 may be configured to be communicable with an external network by housing the host computer 400 provided with communication means such as a modem in the same casing. Alternatively, for example, the CPU (host control means) 401 of the host computer 400 provided with communication means such as i-link directly controls the information recording / reproducing apparatus 300 via the data input / output control means 308 and the bus 309. By doing so, you may be able to communicate with an external network.
[0061] 光ピックアップ 301は光ディスク 100への記録再生を行うもので、半導体レーザ装 置とレンズから構成される。より詳細には、光ピックアップ 301は、光ディスク 100に対 してレーザービーム等の光ビームを、再生時には読み取り光として第 1のパワーで照 射し、記録時には書き込み光として第 2のパワーで且つ変調させながら照射する。  The optical pickup 301 performs recording / reproduction on the optical disc 100, and includes a semiconductor laser device and a lens. More specifically, the optical pickup 301 irradiates the optical disc 100 with a light beam such as a laser beam at a first power as a read light during reproduction, and modulates with a second power as a write light at the time of recording. Irradiate while letting go.
[0062] 信号記録再生手段 302は、光ピックアップ 301とスピンドルモータ 306とを制御する ことで光ディスク 100に対して記録又は再生を行う。より具体的には、信号記録再生 手段 302は、例えば、レーザダイオードドライバ (LDドライノく)及びヘッドアンプ等に よって構成されている。レーザダイオードドライバは、光ピックアップ 301内に設けられ た図示しない半導体レーザを駆動する。ヘッドアンプは、光ピックアップ 301の出力 信号、即ち、光ビームの反射光を増幅し、該増幅した信号を出力する。より詳細には 、信号記録再生手段 302は、 OPC (Optimum Power Control)処理時には、 CPU31 4の制御下で、図示しないタイミング生成器等と共に、 OPCパターンの記録及び再生 処理により最適なレーザパワーの決定が行えるように、光ピックアップ 301内に設けら れた図示しない半導体レーザを駆動する。特に、信号記録再生手段 302は、光ピッ クアップ 301と共に、本発明に係る「記録再生手段」の一例を構成する。  [0062] The signal recording / reproducing means 302 records or reproduces the optical disc 100 by controlling the optical pickup 301 and the spindle motor 306. More specifically, the signal recording / reproducing means 302 is constituted by, for example, a laser diode driver (LD dryer) and a head amplifier. The laser diode driver drives a semiconductor laser (not shown) provided in the optical pickup 301. The head amplifier amplifies the output signal of the optical pickup 301, that is, the reflected light of the light beam, and outputs the amplified signal. More specifically, the signal recording / reproducing means 302 determines the optimum laser power by OPC pattern recording and reproduction processing together with a timing generator (not shown) under the control of the CPU 314 during OPC (Optimum Power Control) processing. A semiconductor laser (not shown) provided in the optical pickup 301 is driven so that the above can be performed. In particular, the signal recording / reproducing means 302, together with the optical pickup 301, constitutes an example of the “recording / reproducing means” according to the present invention.
[0063] アドレス検出部 303は、信号記録再生手段 302によって出力される、例えばプリフ ォーマットアドレス信号等を含む再生信号力も光ディスク 100におけるアドレス（ァドレ ス情報)を検出する。  The address detection unit 303 also detects an address (address information) in the optical disc 100 for the reproduction signal power output by the signal recording / reproducing means 302, for example, including a pre-format address signal.
[0064] CPU (ドライブ制御手段） 314は、バス 309を介して、各種制御手段に指示を行うこ とで、情報記録再生装置 300全体の制御を行う。尚、 CPU314が動作するためのソ フトウェア又はファームウェアは、メモリ 307に格納されている。特に、 CPU314は、 本発明に係る「制御手段」の一例を構成する。 The CPU (drive control means) 314 controls the entire information recording / reproducing apparatus 300 by giving instructions to various control means via the bus 309. It should be noted that the software for operating CPU314 The software or firmware is stored in the memory 307. In particular, the CPU 314 constitutes an example of “control means” according to the present invention.
[0065] スピンドルモータ 306は光ディスク 100を回転及び停止させるもので、光ディスクへ のアクセス時に動作する。より詳細には、スピンドルモータ 306は、図示しないサーボ ユニット等によりスピンドルサーボを受けつつ所定速度で光ディスク 100を回転及び 停止させるように構成されて 、る。  The spindle motor 306 rotates and stops the optical disc 100 and operates when accessing the optical disc. More specifically, the spindle motor 306 is configured to rotate and stop the optical disc 100 at a predetermined speed while receiving spindle servo from a servo unit or the like (not shown).
[0066] メモリ 307は、記録再生データのバッファ領域や、信号記録再生手段 302で使用出 来るデータに変換する時の中間バッファとして使用される領域など情報記録再生装 置 300におけるデータ処理全般及び OPC処理において使用される。また、メモリ 30 7はこれらレコーダ機器としての動作を行うためのプログラム、即ちファームウェアが格 納される ROM領域と、記録再生データの一時格納用バッファや、ファームウェアプロ グラム等の動作に必要な変数が格納される RAM領域など力 構成される。  [0066] The memory 307 includes general data processing and OPC in the information recording / reproducing apparatus 300 such as a buffer area for recording / reproducing data and an area used as an intermediate buffer when converted into data used by the signal recording / reproducing means 302. Used in processing. The memory 307 has a program for operating as a recorder device, that is, a ROM area in which firmware is stored, a buffer for temporarily storing recording / playback data, a variable necessary for the operation of the firmware program, and the like. The RAM area to be stored is configured.
[0067] データ入出力制御手段 308は、情報記録再生装置 300に対する外部からのデー タ入出力を制御し、メモリ 307上のデータバッファへの格納及び取り出しを行う。情報 記録再生装置 300と、 SCSIや ATAPI等のインターフェースを介して接続されて!、る 外部のホストコンピュータ 400 (以下、適宜ホストと称す)から発行されるドライブ制御 命令は、当該データ入出力制御手段 308を介して CPU314に伝達される。また、記 録再生データも同様にして、当該データ入出力制御手段 308を介して、ホストコンビ ユータ 400に対して送受信される。  Data input / output control means 308 controls external data input / output to / from information recording / reproducing apparatus 300, and stores and retrieves data in / from data buffer on memory 307. Connected to the information recording / reproducing apparatus 300 via an interface such as SCSI or ATAPI! The drive control command issued from the external host computer 400 (hereinafter referred to as a host as appropriate) is the data input / output control means. It is transmitted to CPU 314 via 308. Similarly, recording / reproduction data is transmitted / received to / from the host computer 400 via the data input / output control means 308.
[0068] ホストコンピュータ 400における、 CPU (ホスト制御手段） 401、メモリ 402、データ入 出力制御手段 406、及びバス 407は、これらに対応される、情報記録再生装置 300 内の構成要素と、概ね同様である。  In the host computer 400, the CPU (host control means) 401, the memory 402, the data input / output control means 406, and the bus 407 are substantially the same as the corresponding components in the information recording / reproducing apparatus 300. It is.
[0069] 操作制御手段 403は、ホストコンピュータ 400に対する動作指示受付と表示を行う もので、例えば記録又は再生と 、つた操作ボタン 404による指示を CPU401に伝え る。 CPU401は、操作制御手段 403からの指示情報を元に、データ入出力手段 406 を介して、情報記録再生装置 300に対して制御命令 (コマンド)を送信し、情報記録 再生装置 300全体を制御するように構成してもよい。同様に、 CPU401は、情報記 録再生装置 300に対して、動作状態をホストに送信するように要求するコマンドを送 信することができる。これにより、記録中や再生中といった情報記録再生装置 300の 動作状態が把握できるため CPU401は、操作制御手段 403を介して蛍光管や LCD などの表示パネル 405に情報記録再生装置 300の動作状態を出力することができる [0069] The operation control means 403 receives and displays an operation instruction for the host computer 400. For example, the operation control means 403 transmits an instruction by the operation button 404 to the CPU 401 for recording or reproduction. Based on the instruction information from the operation control means 403, the CPU 401 transmits a control command (command) to the information recording / reproducing apparatus 300 via the data input / output means 406 to control the entire information recording / reproducing apparatus 300. You may comprise as follows. Similarly, the CPU 401 sends a command requesting the information recording / reproducing apparatus 300 to send the operation status to the host. I can believe. As a result, since the operation state of the information recording / reproducing apparatus 300 such as recording or reproduction can be grasped, the CPU 401 displays the operation state of the information recording / reproducing apparatus 300 on the display panel 405 such as a fluorescent tube or LCD via the operation control means 403. Can output
[0070] 以上説明した、情報記録再生装置 300とホストコンピュータ 400を組み合わせて使 用する一具体例は、映像を記録再生するレコーダ機器等の家庭用機器である。この レコーダ機器は放送受信チューナや外部接続端子力ゝらの映像信号をディスクに記録 し、テレビなど外部表示機器にディスクから再生した映像信号を出力する機器である[0070] One specific example of using the information recording / reproducing apparatus 300 and the host computer 400 in combination as described above is a household device such as a recorder device that records and reproduces video. This recorder device is a device that records video signals from broadcast receiver tuners and external connection jacks on a disc, and outputs the video signals reproduced from the disc to an external display device such as a television.
。メモリ 402に格納されたプログラムを CPU401で実行させることでレコーダ機器とし ての動作を行っている。また、別の具体例では、情報記録再生装置 300はディスクド ライブ（以下、適宜ドライブと称す)であり、ホストコンピュータ 400はパーソナルコンビ ユータゃワークステーションである。パーソナルコンピュータ等のホストコンピュータと ドライブは SCSIや ATAPIと ヽつたデータ入出力制御手段 308 (406)を介して接続 されており、ホストコンピュータにインストールされているライティングソフトウェア等の アプリケーションが、ディスクドライブを制御する。 . The program stored in the memory 402 is executed by the CPU 401 to operate as a recorder device. In another specific example, the information recording / reproducing apparatus 300 is a disk drive (hereinafter referred to as a drive as appropriate), and the host computer 400 is a personal computer workstation. The host computer such as a personal computer and the drive are connected via SCSI / ATAPI data input / output control means 308 (406), and the application such as writing software installed in the host computer controls the disk drive. To do.
[0071] (2) 光ピックアップ [0071] (2) Optical pickup
次に、図 2を参照して、本実施例に係る情報記録再生装置 300が備えるピックアツ プ 100のより詳細な構成について説明する。ここに、図 2は、本実施例に係る情報記 録再生装置 300のうち特にピックアップ 100のより詳細な構成を概略的に示すブロッ ク図である。  Next, with reference to FIG. 2, a more detailed configuration of the pickup 100 included in the information recording / reproducing apparatus 300 according to the present embodiment will be described. FIG. 2 is a block diagram schematically showing a more detailed configuration of the pickup 100 in the information recording / reproducing apparatus 300 according to the present embodiment.
[0072] 図 2に示すように、光ピックアップ 301は、ホログラムレーザ 101と、回折格子 102と 、球面収差補正素子 103と、コリメータレンズ 104と、ハーフミラー 105と、対物レンズ 108と、ァクチユエータ部 109と、対物レンズ Z位置センサ 110と、集光レンズ 112と、 ホログラム素子 113と、フォトディテクタ 114と、ピンホール 117と、ピンホール 117の 位置を変化させるァクチユエータ 118と、ピンホール 117の位置の変化を制御するド ライバー 119とを備える。  As shown in FIG. 2, the optical pickup 301 includes a hologram laser 101, a diffraction grating 102, a spherical aberration correction element 103, a collimator lens 104, a half mirror 105, an objective lens 108, and an actuator unit 109. Objective lens Z position sensor 110, condenser lens 112, hologram element 113, photodetector 114, pinhole 117, actuator 118 for changing the position of pinhole 117, and change in the position of pinhole 117. And a driver 119 to be controlled.
[0073] ホログラムレーザ 101は、本発明の「光源」の一具体例を構成しており、図示しない 複数波長のレーザ光 LBを出射可能なレーザチップや基板ゃ受光素子やホログラム 素子などを有して構成されている。レーザチップと受光素子は同一の基板上に配置 されており、ホログラム素子は基板のレーザ光 LBの出力側に対向して設けられてい る。レーザチップは複数種類ある光ディスク 100の種別に応じたレーザ光 LBを放射 するようにしてもよい。ホログラムレーザ 11は、複数の光源及びディテクタとしての機 能を有しているようにしてもよい。或いは、レーザチップ及び受光素子等を一つにまと めて備えるホログラムレーザ 101に代えて、複数のレーザチップや複数の受光素子 を別個に備える構成を採用してもよ!、。 The hologram laser 101 constitutes one specific example of the “light source” of the present invention, and a laser chip, a substrate, a light receiving element, or a hologram capable of emitting laser light LB having a plurality of wavelengths (not shown). It has elements and the like. The laser chip and the light receiving element are arranged on the same substrate, and the hologram element is provided facing the laser beam LB output side of the substrate. The laser chip may emit a laser beam LB corresponding to the type of the optical disc 100 having a plurality of types. The hologram laser 11 may have functions as a plurality of light sources and detectors. Alternatively, instead of the hologram laser 101 including a laser chip and a light receiving element as a whole, a configuration including a plurality of laser chips and a plurality of light receiving elements separately may be adopted!
[0074] 回折格子 102は、ホログラムレーザ 101から射出されたレーザ光を、 0次光と、 + 1 次回折光及び 1次回折光とに回折する。  The diffraction grating 102 diffracts the laser light emitted from the hologram laser 101 into 0th-order light, + first-order diffracted light, and first-order diffracted light.
[0075] 球面収差補正素子 103は、光ディスク 100の基板厚に応じて、最適な球面収差補 正を行う。  The spherical aberration correcting element 103 performs optimal spherical aberration correction according to the substrate thickness of the optical disc 100.
[0076] コリメータレンズ 104は、入射したレーザ光 LBを略平行光にして、ハーフミラー 105 に人射させる。  The collimator lens 104 converts the incident laser light LB into substantially parallel light and causes the half mirror 105 to radiate humans.
[0077] ハーフミラー 105は、ホログラムレーザ 101の側から入射するレーザ光 LBをそのま ま 100%透過し、光ディスク 100の側力も入射するレーザ光 LB (即ち、レーザ光 LB の光ディスク 100からの反射光）を 90%だけ透過し且つ 10%だけ反射する。ハーフミ ラー 105において反射された 10%の反射光は、集光レンズ 112及びホログラム素子 113を介してフォトディテクタ 114に集光される。  The half mirror 105 transmits 100% of the laser beam LB incident from the hologram laser 101 side as it is, and also reflects the laser beam LB (that is, the reflection of the laser beam LB from the optical disc 100) on which the side force of the optical disc 100 is also incident. Light) is transmitted by 90% and reflected by 10%. 10% of the reflected light reflected by the half mirror 105 is condensed on the photodetector 114 via the condenser lens 112 and the hologram element 113.
[0078] 開口制限素子 106は、例えば液晶シャツタ等を備えており、光ディスク 100の基板 厚 (言い換えれば、種類）に応じて、レーザ光 LBの出射側における対物レンズ 108 の開口数（NA： Numerical Aperture)を実質的に変化させるようにしてもよ！、。  The aperture limiting element 106 includes, for example, a liquid crystal shirt, and the numerical aperture (NA: Numerical value) of the objective lens 108 on the laser beam LB emission side according to the substrate thickness (in other words, the type) of the optical disc 100. Let Aperture) change substantially! ,.
[0079] ピンホール 117は、所定の大きさを有する開口部、所謂、穴を備え、当該開口部を 通過させることで、レーザ光を空間的にフィルタリングすることが可能な部材である。  [0079] The pinhole 117 is a member that has an opening having a predetermined size, a so-called hole, and is capable of spatially filtering laser light by passing through the opening.
[0080] 対物レンズ 108は、本発明の「光学系」の一具体例を構成しており、入射するレー ザ光 LBを集光して、光ディスク 100の記録面上に照射する。  The objective lens 108 constitutes a specific example of the “optical system” of the present invention. The objective lens 108 collects the incident laser beam LB and irradiates it on the recording surface of the optical disc 100.
[0081] ァクチユエータ部 109は、本発明の「光学系」の他の具体例を構成しており、対物レ ンズ 108の配置位置を変更するための駆動機構を有している。より具体的には、ァク チユエータ部 109は、対物レンズ 108の位置をフォーカス方向（Z方向であって、図 2 における左右の方向）に移動させる。 The actuator unit 109 constitutes another specific example of the “optical system” of the present invention, and has a drive mechanism for changing the arrangement position of the objective lens 108. More specifically, the actuator unit 109 determines the position of the objective lens 108 in the focus direction (Z direction, FIG. Left and right direction).
[0082] 対物レンズ Z位置センサ 110は、対物レンズの Z方向における絶対的な或いは相対 的な位置（即ち、レーザ光 LBの光軸に沿った方向ないしはフォーカス方向における 絶対的な或いは相対的な位置）を測定する。また、対物レンズ Z位置センサ 110は、 測定された対物レンズの Z方向における位置を、後述のディスク判別部 314bへ出力 する。  The objective lens Z position sensor 110 is an absolute or relative position in the Z direction of the objective lens (that is, an absolute or relative position in the direction along the optical axis of the laser beam LB or in the focus direction). ). Further, the objective lens Z position sensor 110 outputs the measured position of the objective lens in the Z direction to a disc determination unit 314b described later.
[0083] 集光レンズ 112は、ハーフミラー 105において反射された反射光魏光する。  The condensing lens 112 fluoresces the reflected light reflected by the half mirror 105.
[0084] ホログラム素子 113は、集光レンズ 112と集光レンズ 112により集光された反射光の 集光点との間に配置される。ホログラム素子 113は、該ホログラム素子 113上に形成 される反射光のスポットを、複数の分割されたスポット領域に分割し、且つ夫々のスポ ット領域における反射光の一部を、フォトディテクタ 114に集光する。 The hologram element 113 is disposed between the condensing lens 112 and the condensing point of the reflected light collected by the condensing lens 112. The hologram element 113 divides the reflected light spot formed on the hologram element 113 into a plurality of divided spot areas, and collects a part of the reflected light in each spot area in the photodetector 114. Shine.
[0085] フォトディテクタ 114は、本発明の「受光手段」の一具体例を構成しており、ホロダラ ム素子 113により集光される複数のスポット領域における反射光の一部を受光し、そ の光強度レベル等を検出する。フォトディテクタ 114は、検出された光強度レベル等 を、後述の演算部 314cに出力する。 The photo detector 114 constitutes a specific example of the “light receiving means” of the present invention, and receives a part of the reflected light in a plurality of spot regions collected by the hologram element 113 and transmits the light. Detect the intensity level. The photodetector 114 outputs the detected light intensity level and the like to the calculation unit 314c described later.
[0086] また、 CPU314は、その内部にピンホール位置制御部 314aと、ディスク判別部 31Further, the CPU 314 includes a pinhole position control unit 314a and a disk determination unit 31 therein.
4bと、演算部 314cとを備える。 4b and a calculation unit 314c.
[0087] ピンホール位置制御部 314aは、上述したドライバー 119と共に、ピンホール 117の[0087] The pinhole position control unit 314a includes the driver 119 and the pinhole 117.
、例えば Z軸方向の位置を制御する。 For example, the position in the Z-axis direction is controlled.
[0088] ディスク判別部 314bは、対物レンズ Z位置センサ 110より出力される対物レンズの[0088] The disc determination unit 314b is configured to detect the objective lens output from the objective lens Z position sensor 110.
Z方向における絶対的な或いは相対的な位置、及びホログラムレーザ 101から出力 される反射光の検出信号に基づいて、情報記録再生装置 300にローデイングされてBased on the absolute or relative position in the Z direction and the detection signal of the reflected light output from the hologram laser 101, it is loaded into the information recording / reproducing apparatus 300.
V、る光ディスク 100の種類 (或いは、基板厚）を判別する。 V, discriminate the type (or substrate thickness) of the optical disc 100.
[0089] 演算部 314cは、本発明の「演算手段」の一具体例を構成しており、フォトディテクタThe calculation unit 314c constitutes one specific example of the “calculation means” of the present invention, and is a photo detector.
114より出力される光強度レベル等に基づ!/、て、実際に生じて 、る信号成分の量を 算出する。 Based on the light intensity level output from 114, etc., the amount of the signal component actually generated is calculated.
[0090] (3) 一の戻り光を選択的に受光手段に受光させる光学素子の一具体例  [0090] (3) A specific example of an optical element for selectively receiving one return light by the light receiving means
次に、図 3及び図 4を参照して、本実施例に係る一の戻り光を選択的に受光手段に 受光させる光学素子 (以下、適宜、「一の戻り光を選択する光学素子」と称す)の一具 体例について説明する。 Next, referring to FIG. 3 and FIG. 4, one return light according to the present embodiment is selectively used as a light receiving means. A specific example of an optical element that receives light (hereinafter, appropriately referred to as “an optical element that selects one return light”) will be described.
[0091] (3- 1) 共焦点光学系  [0091] (3-1) Confocal optical system
先ず、図 3を参照して、本実施例に係る共焦点光学系について説明する。ここに、 図 3は、本実施例に係る共焦点光学系を図式的に示す模式図である。尚、図 3及び 後述される図 4等における、光軸方向は、 Z軸方向として示されている。  First, the confocal optical system according to the present embodiment will be described with reference to FIG. FIG. 3 is a schematic diagram schematically showing the confocal optical system according to the present embodiment. The optical axis direction in FIG. 3 and FIG. 4 described later is shown as the Z-axis direction.
[0092] 図 3に示されるように、一般的に、記録層毎に共焦点位置が異なる。ここに、本実施 例に係る「共焦点位置」とは、レーザ光が照射され、一の記録層に合焦点され、散乱 又は反射された戻り光力 集光レンズにより、再度、合焦点される位置のことである。 また、一の記録層における集光点位置と、共焦点位置とは、共役な関係にあるともい  As shown in FIG. 3, the confocal position is generally different for each recording layer. Here, the “confocal position” according to the present embodiment is a laser beam irradiated, focused on one recording layer, and focused again by a reflected light collecting lens that is scattered or reflected. It is a position. In addition, the condensing position and the confocal position in one recording layer may have a conjugate relationship.
[0093] 具体的には、 CPU314の制御下で、ァクチユエータ部 109、及び対物レンズ 108 によって、レーザ光 LB力 L1層に合焦点され、散乱又は反射された戻り光が、集光 レンズ 112により、再度、 Z軸方向の共焦点位置「XI」において合焦点される。他方、 CPU314の制御下で、ァクチユエータ部 109、及び対物レンズ 108によって、レーザ 光 LBが、 L2層に合焦点され、散乱又は反射された戻り光が、集光レンズ 112により 、再度、 Z軸方向の共焦点位置「X2」において合焦点される。尚、本発明に係る「一 の戻り光」の一具体例が、「L1層に合焦点され、散乱又は反射された戻り光」又は「L 2層に合焦点され、散乱又は反射された戻り光」によって構成されている。 Specifically, under the control of the CPU 314, the return light focused and scattered or reflected by the laser beam LB force L 1 layer by the actuator unit 109 and the objective lens 108 is reflected by the condenser lens 112. Again, focusing is performed at the confocal position “XI” in the Z-axis direction. On the other hand, under the control of the CPU 314, the laser beam LB is focused on the L2 layer by the actuator unit 109 and the objective lens 108, and the returned light that is scattered or reflected is again returned to the Z-axis direction by the condenser lens 112. Is focused at the confocal position “X2”. A specific example of “one return light” according to the present invention is “return light focused on and scattered or reflected on the L1 layer” or “return light focused on and scattered or reflected on the L2 layer”. It is composed of “light”.
[0094] 以上のように、各記録層における集光点位置と、共焦点位置とは、一般的に、一対 一に夫々対応付けられている。この共焦点光学系によれば、光路の設計の際の微調 整をより高精度に行うことが可能である。従って、共焦点位置の時系列的な変化に対 応することが好ましい。  As described above, the condensing point position and the confocal position in each recording layer are generally associated one-to-one. According to this confocal optical system, it is possible to perform fine adjustment at the time of designing the optical path with higher accuracy. Therefore, it is preferable to cope with time-series changes in the confocal position.
[0095] (3- 2)一の戻り光を選択する光学素子の一具体例  [0095] (3-2) One specific example of optical element for selecting one return light
次に、図 4を参照して、本発明に係る、一の戻り光を選択する光学素子の一具体例 について説明する。ここに、図 4は、本実施例に係る、一の戻り光を選択する光学素 子の一具体例を図式的に示す模式図である。  Next, referring to FIG. 4, a specific example of an optical element for selecting one return light according to the present invention will be described. FIG. 4 is a schematic diagram schematically showing one specific example of the optical element for selecting one return light according to the present embodiment.
[0096] 図 4に示されるように、 CPU314の制御下で、ァクチユエータ部 109、及び対物レン ズ 108によって、レーザ光 LBが、 L2層に合焦点され、散乱又は反射された戻り光が 、集光レンズ 112により、再度、 Z軸方向の共焦点位置「X2」において合焦点される。 特に、本実施例によれば、 Z軸方向に位置を変動可能なピンホール 117を備えて構 成されている。そして、ピンホール位置制御部 314aの制御下で、ピンホール 117の 開口部と、共焦点位置「X2」とを略一致させることが可能である。尚、ピンホール 117 の位置は、 Z軸方向に加えて、 Z軸方向と直交する X軸方向や Y軸方向においても変 動可能であるようにしてもょ 、。 As shown in FIG. 4, the actuator unit 109 and the objective lens are controlled under the control of the CPU 314. 108, the laser beam LB is focused on the L2 layer, and the scattered or reflected return light is focused again at the confocal position “X2” in the Z-axis direction by the condenser lens 112. In particular, according to the present embodiment, the pin hole 117 whose position can be changed in the Z-axis direction is provided. Then, under the control of the pinhole position control unit 314a, the opening of the pinhole 117 and the confocal position “X2” can be substantially matched. It should be noted that the position of the pinhole 117 can be changed not only in the Z-axis direction but also in the X-axis direction and the Y-axis direction orthogonal to the Z-axis direction.
[0097] 具体的には、ピンホール 117において、 L2層力 の戻り光が合焦点した場合、この 共焦点位置「X2」では、 L2層力もの戻り光の成分を最大限含んだ戻り光だけが選択 的に、このピンホール 117の開口部を通過することができる。他方で、この場合、迷光 (例えば L1層からの戻り光）は、合焦点していないので、ピンホール 117の位置にお いて、迷光の光束の光径が大きくなつている。よって、迷光はピンホールの位置で拡 がってしまうので、ピンホール 117の開口部を殆ど又は完全に通過することができな いので、迷光の成分を最大限、空間的にフィルタリング (遮断)することが可能である 。尚、ピンホール 117において、 L1層からの戻り光が合焦点した場合、共焦点位置「 XI」に位置するピンホール 117によって、例えば L2層からの戻り光等の迷光の成分 を空間的にフィルタリングできる作用についても概ね同様に説明することができる。  [0097] Specifically, when the return light of the L2 layer force is focused at the pinhole 117, only the return light including the maximum amount of the return light component of the L2 layer force at the confocal position "X2". Can selectively pass through the opening of this pinhole 117. On the other hand, in this case, since stray light (for example, return light from the L1 layer) is not focused, the diameter of the stray light beam is increased at the position of the pinhole 117. Therefore, since stray light spreads at the pinhole position, it can hardly or completely pass through the opening of the pinhole 117, so that stray light components can be spatially filtered (blocked) to the maximum. Is possible. When the return light from the L1 layer is focused on the pinhole 117, for example, the stray light component such as the return light from the L2 layer is spatially filtered by the pinhole 117 located at the confocal position “XI”. The actions that can be performed can be generally described in the same manner.
[0098] この結果、迷光の影響を顕著に低減させることで、所望の記録層からの戻り光の信 号成分の SZN比を向上させ、多層型の光ディスクに対する再生又は記録の際に、 データの再生又は記録を、より高精度に実現することが可能である。  As a result, the influence of stray light is remarkably reduced, so that the SZN ratio of the signal component of the return light from the desired recording layer is improved, and data is reproduced during reproduction or recording on a multilayer optical disc. Reproduction or recording can be realized with higher accuracy.
[0099] (3- 3)一の戻り光を選択する光学素子の他の具体例  [0099] (3-3) Other Specific Examples of Optical Element for Selecting One Return Light
次に、図 5を参照して、本発明に係る、一の戻り光を受光する受光素子の他の具体 例について説明する。ここに、図 5は、本実施例に係る、一の戻り光を受光する受光 素子の他の具体例を図式的に示す模式図である。尚、「A面」は、ピンホールを、戻り 光が照射される側から見た図であり、「B面」は、ピンホールを、受光素子 114aの側か ら見た図である。  Next, with reference to FIG. 5, another specific example of a light receiving element for receiving one return light according to the present invention will be described. FIG. 5 is a schematic diagram schematically showing another specific example of the light receiving element that receives one return light according to the present embodiment. Note that “A surface” is a view of the pinhole as viewed from the side irradiated with the return light, and “B surface” is a view of the pinhole as viewed from the light receiving element 114a side.
[0100] 図 5中の [八面」に示されるように、ピンホール 117は、戻り光が照射される面におい て、例えば 4分割された受光領域を備えるようにしてもよい。従って、戻り光が、ピンホ ール 117を通過する前に、この戻り光を受光することが可能である。この結果、戻り光 力 ピンホール 117を通過した後に、受光素子 114aによって受光される場合と比較 して、迷光の信号レベルに基づいて、ピンホール 117の位置制御や、後述される液 晶レンズによる集光点位置の制御を、適切に行うことが可能である。或いは、ピンホ ール 117は、 4分割された受光領域に加えて、又は、代えて、内周領域と、外周領域 に 2分割された受光領域を備えるようにしてもょ ヽ。 [0100] As shown in [Eight sides] in FIG. 5, the pinhole 117 may include, for example, a light receiving region divided into four on the surface irradiated with the return light. Therefore, the return light is This return light can be received before passing through the control panel 117. As a result, compared with the case where light is received by the light receiving element 114a after passing through the return light pinhole 117, the position of the pinhole 117 is controlled based on the signal level of stray light, or by a liquid crystal lens described later. It is possible to appropriately control the focal point position. Alternatively, the pinhole 117 may be provided with a light receiving area divided into two in an inner peripheral area and an outer peripheral area in addition to or instead of the light receiving area divided into four.
[0101] (4)他の具体例 その 1  [0101] (4) Other examples 1
次に、図 6を参照して、本実施例に係る、一の戻り光を選択する光学素子の他の具 体例（その 1)について説明する。ここに、図 6は、本実施例に係る、一の戻り光を選 択する光学素子の他の具体例 (その 1)を図式的に示す模式図である。尚、他の具体 例（その 1)において、前述した一の具体例における構成と概ね同様の構成には、同 様の符号番号を付し、それらの説明は適宜省略する。  Next, with reference to FIG. 6, another example (part 1) of the optical element for selecting one return light according to the present embodiment will be described. FIG. 6 is a schematic diagram schematically showing another specific example (No. 1) of the optical element for selecting one return light according to the present embodiment. Note that, in other specific examples (part 1), the same reference numerals are given to the configurations that are substantially the same as the configurations in the above-described specific example, and description thereof will be omitted as appropriate.
[0102] 図 6に示されるように、前述の図 4と概ね同様にして、 CPU314の制御下で、ァクチ ユエータ部 109、及び対物レンズ 108によって、レーザ光 LB力 L2層に合焦点され 、散乱又は反射された戻り光が、集光レンズ 112により、再度、 Z軸方向の共焦点位 置「X2」において合焦点される。特に、本実施例によれば、 Z軸方向に位置が固定さ れたピンホール 117a、及び、液晶レンズ 118 (即ち、焦点位置を変化させることが可 能である、焦点可変レンズの一具体例）を備えて構成されている。そして、 CPU314 の制御下で、液晶レンズ 118によって、戻り光の共焦点位置を Z軸方向において調 節可能であるので、ピンホール 117aの開口部と、共焦点位置「X2」とを略一致にさ せることが可能である。尚、焦点可変レンズの具体例を構成する液晶レンズ (液晶層） の詳細な態様については、応用物理 第 63卷 第 1号 （1994年)の 57ページから 58ページを参照されたい。また、焦点可変レンズを構成する電気光学レンズの更に 詳細な態様については、応用物理 第 63卷 第 1号 （1994年)の 59ページから 62 ページを参照されたい。  [0102] As shown in FIG. 6, in substantially the same manner as in FIG. 4, the laser beam LB force is focused on the L2 layer and scattered by the actuator unit 109 and the objective lens 108 under the control of the CPU 314. Alternatively, the reflected return light is focused again at the confocal position “X2” in the Z-axis direction by the condenser lens 112. In particular, according to the present embodiment, the pinhole 117a whose position is fixed in the Z-axis direction and the liquid crystal lens 118 (that is, one specific example of a variable focus lens capable of changing the focal position) ). Under the control of the CPU 314, the confocal position of the return light can be adjusted in the Z-axis direction by the liquid crystal lens 118, so that the opening of the pinhole 117a and the confocal position “X2” are substantially coincident. It is possible to Refer to pages 57 to 58 of Applied Physics 63rd No. 1 (1994) for the detailed mode of the liquid crystal lens (liquid crystal layer) that constitutes a specific example of the variable focus lens. Please refer to pages 59 to 62 of Applied Physics No. 63 卷 No. 1 (1994) for more detailed aspects of the electro-optic lens that constitutes the variable focus lens.
[0103] この結果、前述した図 4における説明と概ね同様にして、迷光の影響を顕著に低減 させることで、所望の記録層からの戻り光の信号成分の SZN比を向上させ、多層型 の光ディスクに対する再生又は記録の際に、データの再生又は記録を、より高精度 に実現することが可能である。 As a result, in substantially the same manner as described above with reference to FIG. 4, the SZN ratio of the signal component of the return light from the desired recording layer is improved by significantly reducing the influence of stray light, and the multilayer type More accurate playback or recording of data during playback or recording on an optical disc Can be realized.
[0104] 特に、他の具体例にぉ 、ては、共焦点位置を変化させるために、例えばモーター 等の機械的駆動装置を備える必要がな 、ため、光ピックアップの小型化や薄型化を 図ることができる。また、機械的駆動装置を備える必要がないため、光ピックアップの 消費電力を抑えることができると 、う利点も有して 、る。  In particular, in other specific examples, in order to change the confocal position, it is not necessary to provide a mechanical drive device such as a motor, so that the optical pickup is reduced in size and thickness. be able to. In addition, since it is not necessary to provide a mechanical drive device, it is possible to reduce the power consumption of the optical pickup.
[0105] (5)他の具体例 その 2 —  [0105] (5) Other examples 2 —
次に、図 7及び図 8を参照して、本実施例に係る、一の戻り光を選択する光学素子 の他の具体例（その 2)について説明する。ここに、図 7は、本実施例に係る、一の戻 り光を選択する光学素子の他の具体例 (その 2)を図式的に示す模式図である。図 8 は、本実施例に係る、受光素子の内周部及び外周部において受光された信号成分 に基づいて、所望となる信号成分を算出する過程を図式的に示すグラフである。尚、 他の具体例（その 2)において、前述した一の具体例における構成と概ね同様の構成 には、同様の符号番号を付し、それらの説明は適宜省略する。  Next, with reference to FIG. 7 and FIG. 8, another specific example (part 2) of the optical element for selecting one return light according to the present embodiment will be described. FIG. 7 is a schematic diagram schematically showing another specific example (No. 2) of the optical element for selecting one return light according to the present embodiment. FIG. 8 is a graph schematically showing a process of calculating a desired signal component based on signal components received at the inner and outer peripheral portions of the light receiving element according to the present embodiment. In the other specific example (No. 2), the same reference numerals are given to the configurations that are substantially the same as the configurations in the above-described specific example, and the description thereof will be omitted as appropriate.
[0106] 図 7に示されるように、例えば前述したピンホール 117等の光学素子によって、受光 素子 114aの内周部（図 7の下側部の図も参照）は、選択的に、即ち、相対的に高い レベルで L2層からの戻り光を受光する。と共に、受光素子 114aの外周部（図 7の下 側部の図も参照）は、選択的に、即ち、相対的に高いレベルで迷光 (例えば L1層か らの戻り光）を受光する。 CPU314の制御下で、 L2層からの戻り光に対応される L2 層からの信号成分、及び、 L1層からの迷光に対応される L1層からの信号成分に基 づいて、光学系は、レーザ光を L2層又は L1層に導くことが可能である。尚、受光素 子 114aの内周部によって、本発明に係る「第 1受光素子」の一具体例が構成される と共に、受光素子 114aの外周部によって、本発明に係る「第 2受光素子」の一具体 例が構成されるようにしてもょ ヽ。  [0106] As shown in FIG. 7, for example, by the optical element such as the pinhole 117 described above, the inner peripheral part of the light receiving element 114a (see also the lower part of FIG. 7) is selectively, that is, The return light from the L2 layer is received at a relatively high level. At the same time, the outer peripheral portion of the light receiving element 114a (see also the lower side of FIG. 7) selectively receives stray light (for example, return light from the L1 layer) at a relatively high level. Under the control of the CPU 314, the optical system is based on the signal component from the L2 layer corresponding to the return light from the L2 layer and the signal component from the L1 layer corresponding to the stray light from the L1 layer. It is possible to guide light to the L2 or L1 layer. A specific example of the “first light receiving element” according to the present invention is configured by the inner peripheral portion of the light receiving element 114a, and the “second light receiving element” according to the present invention is configured by the outer peripheral portion of the light receiving element 114a. Let's make a concrete example of this.
[0107] また、信号成分は、 RF信号、ゥォブル信号、及び、アドレス信号 (LPP)のうち少なく とも一つであるようにしてもよい。或いは、信号成分は、フォーカスサーボ、又はトラッ キングサーボを行うための制御信号であるようにしてもょ 、。  [0107] Further, the signal component may be at least one of an RF signal, a wobble signal, and an address signal (LPP). Alternatively, the signal component may be a control signal for performing focus servo or tracking servo.
[0108] 詳細には、図 8の上側のグラフに示されるように、 CPU314又は演算部 314cの制 御下で、例えば、受光素子 114aの内周部（図 8中の「PD (Photo Detector)の内周部 」を参照)で検出された信号成分から、受光素子 114aの外周部（図 8中の「PDの外 周部」を参照)で検出された信号成分を差分成分として、オフセット (減算)させること で、迷光の影響のない L2層（又は L1層）からの戻り光における理想的な信号成分を 検出することが可能である。この信号成分のオフセットを行う処理は、次式（1)のよう に表現される。 More specifically, as shown in the upper graph of FIG. 8, under the control of the CPU 314 or the arithmetic unit 314c, for example, the inner periphery of the light receiving element 114a (“PD (Photo Detector) in FIG. 8” Inner circumference The signal component detected at the outer periphery of the light receiving element 114a (see “PD outer periphery” in FIG. 8) is offset (subtracted) from the signal component detected at Thus, it is possible to detect the ideal signal component in the return light from the L2 layer (or L1 layer) that is not affected by stray light. The process of offsetting this signal component is expressed as the following equation (1).
[0109] (所望の信号成分） [0109] (desired signal component)
= (受光素子の内周部の信号成分）一「K」 X (受光素子の外周部の信号成分） = (Signal component of the inner periphery of the light receiving element) One “K” X (Signal component of the outer peripheral part of the light receiving element)
…… 式 (1) ...... Formula (1)
但し、「Κ」は、可変な係数である。特に、受光素子の Ζ軸方向における位置変化や ピンホールの大きさに応じて、係数「Κ」は他の層力 の迷光が最小になるように最適 化される。この最適化は、実験的、理論的、経験的、シミュレーション等に基づいて、 個別具体的に行われる。  However, “Κ” is a variable coefficient. In particular, the coefficient “Κ” is optimized to minimize stray light from other layer forces depending on the position change of the light receiving element in the Ζ axis direction and the size of the pinhole. This optimization is performed on an individual basis based on experimental, theoretical, empirical, simulation, etc.
[0110] より詳細には、受光素子 114aの内周部で検出された信号成分が、次式（2)で示さ れ、受光素子 114aの外周部で検出された信号成分が、次式 (3)で示された場合に ついて考察する。 More specifically, the signal component detected at the inner periphery of the light receiving element 114a is expressed by the following equation (2), and the signal component detected at the outer periphery of the light receiving element 114a is expressed by the following equation (3) Consider the case indicated by).
[0111] (受光素子の内周部の信号成分） [0111] (Signal component of the inner periphery of the light receiving element)
= 「L2」 +「L2」 +「L2」 +「L 1」 +「L2」 +「L2」 +「L 1」  = "L2" + "L2" + "L2" + "L 1" + "L2" + "L2" + "L 1"
= 5 X「L2」 + 2 X「L1」 …… 式（2)  = 5 X "L2" + 2 X "L1" ...... Formula (2)
但し、「L2」は、 L2層からの戻り光に対応される信号成分であり、「L1」は、 L1層か らの戻り光に対応される信号成分である。  However, “L2” is a signal component corresponding to the return light from the L2 layer, and “L1” is a signal component corresponding to the return light from the L1 layer.
[0112] (受光素子の外周部の信号成分） [0112] (Signal component of the outer periphery of the light receiving element)
= 2 X「L2」 + 5 X「L1」 …… 式（3)。 = 2 X “L2” + 5 X “L1” …… Equation (3).
[0113] 従って、上述した式（ 1)、式（2)、及び式（3)に加えて、係数「K」を「2Ζ5 (5分の 2 )」にすることで、次の式（la)が得られ、 L2層からの戻り光における理想的な信号成 分を算出することが可能である。 Therefore, in addition to the above-described equations (1), (2), and (3), the coefficient “K” is set to “2Ζ5 (2/5)”, so that the following equation (la ) And the ideal signal component in the return light from the L2 layer can be calculated.
[0114] (L2層からの戻り光における理想的な信号成分） [0114] (Ideal signal component in the return light from the L2 layer)
= 5 X「L2」+ 2 X「L1」 一 K{2 X「L2」+ 5 X「L1」} = (21/5) X TL2J …… 式（la)。 = 5 X "L2" + 2 X "L1" One K {2 X "L2" + 5 X "L1"} = (21/5) X TL2J Equation (la).
[0115] この結果、（i)受光素子 114aの内周部において、選択的に、即ち、相対的に高い レベルで受光された L2層からの戻り光の信号成分、及び (ii)受光素子 114aの外周 部において、選択的に受光された L1層からの戻り光の信号成分に基づいて、 L2層 力もの戻り光における理想的な信号成分を算出することが可能である。  As a result, (i) the signal component of the return light from the L2 layer selectively received at the inner periphery of the light receiving element 114a, that is, at a relatively high level, and (ii) the light receiving element 114a Based on the signal component of the return light from the L1 layer that is selectively received at the outer periphery, the ideal signal component in the return light of the L2 layer can be calculated.
[0116] 或いは、上述した式（1)、式（2)、及び式（3)に加えて、係数「K」を「5Z2 (2分の 5 )」にすることで、次の式（lb)が得られ、 L1層からの戻り光における理想的な信号成 分を算出することが可能である。  [0116] Alternatively, by adding the coefficient “K” to “5Z2 (5/2)” in addition to the above-described equations (1), (2), and (3), the following equation (lb ) And the ideal signal component in the return light from the L1 layer can be calculated.
[0117] (L1層からの戻り光における理想的な信号成分）  [0117] (Ideal signal component in the return light from the L1 layer)
= 5 X「L2」+ 2 X「L1」 一 K{2 X「L2」+ 5 X「L1」}  = 5 X "L2" + 2 X "L1" One K {2 X "L2" + 5 X "L1"}
= (- T21/2J ) X TLIJ …… 式（lb)。  = (-T21 / 2J) X TLIJ ...... Formula (lb).
[0118] この結果、（i)受光素子 114aの内周部において、選択的に、即ち、相対的に高い レベルで受光された L2層からの戻り光の信号成分、及び (ii)受光素子 114aの外周 部において、選択的に受光された L1層からの戻り光の信号成分に基づいて、 L1層 力もの戻り光における理想的な信号成分を算出することが可能である。  As a result, (i) the signal component of the return light from the L2 layer selectively received at the inner periphery of the light receiving element 114a, that is, at a relatively high level, and (ii) the light receiving element 114a Based on the signal component of the return light from the L1 layer that is selectively received at the outer periphery, the ideal signal component in the return light of the L1 layer can be calculated.
[0119] 以上の結果、本実施例に係る、一の戻り光を選択する光学素子の他の具体例（そ の 2)によれば、迷光の影響を顕著に低減させることに加えて、迷光の影響を定量的 又は定性的に把握し、積極的に利用することで、所望とする戻り光における理想的な 信号成分を算出可能であり、多層型の光ディスクに対する再生又は記録の際に、デ ータの再生又は記録を、より高精度に実現することが可能である。  As a result of the above, according to another specific example (part 2) of the optical element that selects one return light according to the present embodiment, in addition to significantly reducing the influence of stray light, stray light Quantitatively or qualitatively grasping the effects of noise and using them actively, it is possible to calculate the ideal signal component in the desired return light. It is possible to realize data reproduction or recording with higher accuracy.
[0120] 或いは、図 7の下側に示されるように、受光素子の内周部の面積を変化させること で、迷光の影響の度合いに基づいて、所望とする戻り光における理想的な信号成分 をより高精度に算出することが可能である。具体的には、戻り光の光径が相対的に大 きい場合 (即ち、受光素子に照射される戻り光の光量が相対的に多量である場合)、 受光素子の内周部の半径を相対的に大きくしてもよいし、或いは、戻り光の光径が相 対的に小さい場合 (即ち、受光素子に照射される戻り光の光量が相対的に少量であ る場合)、受光素子の内周部の半径を相対的に小さくするようにしてもよい。  [0120] Alternatively, as shown in the lower side of FIG. 7, by changing the area of the inner periphery of the light receiving element, an ideal signal component in the desired return light based on the degree of the influence of stray light Can be calculated with higher accuracy. Specifically, when the light diameter of the return light is relatively large (that is, when the amount of the return light irradiated to the light receiving element is relatively large), the radius of the inner periphery of the light receiving element is relatively If the light diameter of the return light is relatively small (that is, the amount of the return light irradiated to the light receiving element is relatively small), the light receiving element You may make it make the radius of an inner peripheral part relatively small.
[0121] (6)他の具体例 その 3 — 次に、図 9を参照して、本実施例に係る、一の戻り光を選択する光学素子の他の具 体例（その 3)について説明する。ここに、図 9は、本実施例に係る、一の戻り光を選 択する光学素子の他の具体例 (その 3)を図式的に示す模式図である。尚、他の具体 例（その 3)において、前述した一の具体例における構成と概ね同様の構成には、同 様の符号番号を付し、それらの説明は適宜省略する。 [0121] (6) Other specific examples 3 — Next, with reference to FIG. 9, another example (part 3) of the optical element for selecting one return light according to the present embodiment will be described. FIG. 9 is a schematic diagram schematically showing another specific example (part 3) of the optical element for selecting one return light according to the present embodiment. In the other specific example (No. 3), the same reference numerals are given to the configurations substantially the same as the configuration in the above-described specific example, and the description thereof will be omitted as appropriate.
[0122] 図 9に示されるように、ホログラム素子 113によって、例えば L2層等の所望の記録 層からの戻り光の共焦点位置を受光素子 114bと、略同じ位置にすることで、例えば L2層等の所望の記録層からの戻り光を選択的に、即ち、相対的に高いレベルで受 光することが可能である。特に、この受光素子 114bの形状や面積は、例えばホログ ラム素子 113等の光学素子や、集光レンズ 112等の光学系における、光学的な特性 又は物理的 (磁気的や電気的)な特性に基づ 、て規定することが可能である。加えて 、この受光素子 114bの形状や面積は、例えば L1層からの戻り光等の迷光が照射さ れないように、光学素子や光学系における、各種の特性に基づいて規定することも可 能である。 [0122] As shown in FIG. 9, by using the hologram element 113, for example, the confocal position of the return light from a desired recording layer such as the L2 layer is made substantially the same as that of the light receiving element 114b. It is possible to selectively receive the return light from a desired recording layer, such as a relatively high level. In particular, the shape and area of the light receiving element 114b are optical characteristics or physical (magnetic or electrical) characteristics in an optical element such as the hologram element 113 and an optical system such as the condenser lens 112, for example. It is possible to specify based on this. In addition, the shape and area of the light receiving element 114b can be defined based on various characteristics of the optical element and the optical system so that stray light such as return light from the L1 layer is not irradiated. It is.
[0123] この結果、受光素子の形状や面積に基づいて、迷光の影響を効果的に低減させる ことで、所望の記録層からの戻り光の信号成分の SZN比を向上させ、多層型の光デ イスクに対する再生又は記録の際に、データの再生又は記録を、より高精度に実現 することが可能である。  As a result, by effectively reducing the influence of stray light based on the shape and area of the light receiving element, the SZN ratio of the signal component of the return light from the desired recording layer is improved, and the multilayer light When reproducing or recording on a disk, it is possible to achieve data reproduction or recording with higher accuracy.
[0124] (7)他の具体例 その 4  [0124] (7) Other examples 4
次に、図 10を参照して、本実施例に係る、一の戻り光を選択する光学素子の他の 具体例（その 4)について説明する。ここに、図 10は、本実施例に係る、一の戻り光を 選択する光学素子の他の具体例 (その 4)を図式的に示す模式図である。尚、他の具 体例（その 4)において、前述した一の具体例における構成と概ね同様の構成には、 同様の符号番号を付し、それらの説明は適宜省略する。  Next, another specific example (No. 4) of the optical element for selecting one return light according to the present embodiment will be described with reference to FIG. FIG. 10 is a schematic diagram schematically showing another specific example (No. 4) of the optical element for selecting one return light according to the present embodiment. In the other specific examples (No. 4), the same reference numerals are given to the configurations that are substantially the same as the configurations in the one specific example described above, and the description thereof will be omitted as appropriate.
[0125] 図 10に示されるように、ホログラム素子 113によって、例えば L2層等の所望の記録 層からの戻り光のうち RF信号に対応される信号光の集光点位置を RF用受光素子 1 14rと、略同じ位置にする。よって、 RF用受光素子 114rにおいて、所望の記録層か らの戻り光のうち RF信号に対応される信号光を選択的に、即ち、相対的に高いレべ ルで受光することが可能である。 [0125] As shown in FIG. 10, the hologram element 113 determines the condensing point position of the signal light corresponding to the RF signal out of the return light from the desired recording layer such as the L2 layer, for example. Set to approximately the same position as 14r. Therefore, in the RF light receiving element 114r, the signal light corresponding to the RF signal out of the return light from the desired recording layer is selectively, that is, a relatively high level. Light can be received.
[0126] 或いは、所望の記録層からの戻り光のうちフォーカスエラー信号 (FE信号)やトラッ キングエラー信号 (TE信号）に対応される信号光の集光点位置を FEZTE用受光素 子 114fと、略同じ位置にする。よって、 FEZTE用受光素子 114fにおいて、所望の 記録層からの戻り光のうち FE信号又は TE信号に対応される信号光を選択的に、即 ち、相対的に高 、レベルで受光することが可能である。  [0126] Alternatively, the focus position of the signal light corresponding to the focus error signal (FE signal) or tracking error signal (TE signal) out of the return light from the desired recording layer can be set as the FEZTE light receiving element 114f. , Make it almost the same position Therefore, the light receiving element 114f for FEZTE can selectively receive the signal light corresponding to the FE signal or TE signal out of the return light from the desired recording layer, that is, at a relatively high level. It is.
[0127] 或いは、戻り光の「0次光」が照射される位置の代わりに、「 + 1次光」又は「一 1次光 」が照射される位置において、 RF用受光素子 114rを配置することで、例えば L1層 力 の戻り光等の迷光が、 RF用受光素子 114rへ照射されることを効果的に低減さ せることも可會である。  Alternatively, instead of the position where the “0th order light” of the return light is irradiated, the RF light receiving element 114r is arranged at the position where the “+ 1st order light” or “first primary light” is irradiated. Thus, for example, stray light such as return light of the L1 layer force can be effectively reduced from irradiating the RF light receiving element 114r.
[0128] この結果、複数の受光素子の配置や役割に基づいて、迷光の影響を効果的に低 減させることで、所望の記録層からの戻り光の信号成分の SZN比を向上させ、多層 型の光ディスクに対する再生又は記録の際に、データの再生又は記録を、より高精 度に実現することが可能である。  As a result, the SZN ratio of the signal component of the return light from the desired recording layer can be improved by effectively reducing the influence of stray light based on the arrangement and roles of the plurality of light receiving elements, and the multilayer When reproducing or recording on a type of optical disc, it is possible to achieve data reproduction or recording with higher accuracy.
[0129] (8) 第 2実施例に係る光ピックアップ  [0129] (8) Optical pickup according to the second embodiment
次に、図 11を参照して、本実施例に係る情報記録再生装置 300が備えるピックアツ プ 100のより詳細な構成について説明する。ここに、図 11は、第 2実施例に係る情報 記録再生装置 300のうち特にピックアップ 100のより詳細な構成を概略的に示すプロ ック図である。  Next, with reference to FIG. 11, a more detailed configuration of the pickup 100 included in the information recording / reproducing apparatus 300 according to the present embodiment will be described. FIG. 11 is a block diagram schematically showing a more detailed configuration of the pickup 100 in the information recording / reproducing apparatus 300 according to the second embodiment.
[0130] 図 11に示すように、第 2実施例に係る、光ピックアップ 301は、上述した実施例から コリメータレンズ 104と、集光レンズ 112とが省略された、ホログラムレーザ 101と、回 折格子 102と、球面収差補正素子 103と、ハーフミラー 105と、対物レンズ 108と、ァ クチユエータ部 109と、対物レンズ Z位置センサ 110と、ホログラム素子 113と、フォト ディテクタ 114と、ピンホール 117とを備える。これらの構成要素は、上述した実施例 と概ね同じなので、便宜上、説明を省略する。  As shown in FIG. 11, the optical pickup 301 according to the second embodiment includes a hologram laser 101, a diffraction grating, and the collimator lens 104 and the condenser lens 112 omitted from the above-described embodiments. 102, spherical aberration correction element 103, half mirror 105, objective lens 108, actuator unit 109, objective lens Z position sensor 110, hologram element 113, photo detector 114, and pinhole 117. . Since these components are generally the same as those in the above-described embodiment, the description thereof is omitted for convenience.
[0131] (8- 1) 第 2実施例に係る、共焦点光学系 (L2層に合焦点した場合）  [0131] (8-1) Confocal optical system according to Example 2 (when focused on L2 layer)
次に、図 12を参照して、 L2層に合焦点した場合における、第 2実施例に係る共焦 点光学系について説明する。ここに、図 12は、第 2実施例に係る共焦点光学系を図 式的に示す模式図である。尚、図 12における、光軸方向は、 Z軸方向として示されて いる。 Next, with reference to FIG. 12, the confocal optical system according to the second example when focused on the L2 layer will be described. Figure 12 shows the confocal optical system according to the second example. It is a schematic diagram shown typically. In FIG. 12, the optical axis direction is shown as the Z-axis direction.
[0132] ここに、本実施例に係る「無限光学系」とは対物レンズに入射する光束は平行光 (コ リメート光）にしている光ピックアップの総称であり、一般的なものであるが光学部品数 が多くなる。また、本実施例に係る「有限光学系」とは対物レンズに入射する光束が 発散光であるピックアップの総称であり、往路と復路のコリメートレンズが不要になる 反面、実効的な対物レンズの NAが高くなるので、対物レンズの性能は高いものを求 められる。  Here, the “infinite optical system” according to the present embodiment is a general term for optical pickups in which the light beam incident on the objective lens is parallel light (collimated light). The number of parts increases. The “finite optical system” according to the present embodiment is a general term for pickups in which the light beam incident on the objective lens is a divergent light, and the collimating lens for the forward path and the backward path is not necessary, but the NA of the effective objective lens Therefore, a high objective lens performance is required.
[0133] 図 12に示されるように、有限光学系においても、一般的に、記録層毎に共焦点位 置が異なる。具体的には、 CPU314の制御下で、ァクチユエータ部 109、及び対物 レンズ 108によって、レーザ光 LB力 L2層に合焦点され、散乱又は反射された戻り 光力 ハーフミラー 105により、再度、 Z軸方向の共焦点位置「X2」において合焦点さ れる。他方、 L2層に合焦点された場合、 L1層からの迷光（図 12中の点線を参照）が 、共焦点位置「X2」力も受光素子に近い位置「XI」において集光される。尚、本発明 に係る「一の戻り光」の一具体例が、「L2層に合焦点され、散乱又は反射された戻り 光」によって構成されている。また、本発明に係る「迷光」の一具体例が、「L2層に合 焦点された場合における、 L1層からの迷光」によって構成されている。  As shown in FIG. 12, even in a finite optical system, the confocal position is generally different for each recording layer. Specifically, under the control of the CPU 314, the laser beam LB force is focused on the L2 layer by the actuator unit 109 and the objective lens 108, and the returned light force scattered or reflected by the half mirror 105 is again used in the Z-axis direction. Is focused at the confocal position “X2”. On the other hand, when focused on the L2 layer, the stray light from the L1 layer (see the dotted line in FIG. 12) is also collected at the position “XI” near the light receiving element with the confocal position “X2” force. A specific example of “one return light” according to the present invention is configured by “return light focused on and scattered or reflected by the L2 layer”. Further, a specific example of “stray light” according to the present invention is configured by “stray light from the L1 layer when focused on the L2 layer”.
[0134] (8- 2) 第 2実施例に係る、共焦点光学系 (L1層に合焦点した場合）  [0134] (8-2) Confocal optical system according to Example 2 (when focused on L1 layer)
次に、図 13を参照して、 L1層に合焦点した場合における、第 2実施例に係る共焦 点光学系について説明する。ここに、図 13は、第 2実施例に係る共焦点光学系を図 式的に示す他の模式図である。尚、図 13における、光軸方向は、 Z軸方向として示さ れている。  Next, with reference to FIG. 13, the confocal optical system according to the second example when focused on the L1 layer will be described. FIG. 13 is another schematic diagram schematically showing the confocal optical system according to the second example. In FIG. 13, the optical axis direction is shown as the Z-axis direction.
[0135] 図 13に示されるように、 L1層に合焦点した場合の有限光学系においては、 CPU3 14の制御下で、ァクチユエータ部 109、及び対物レンズ 108によって、レーザ光 LB 力 L1層に合焦点され、散乱又は反射された戻り光が、ハーフミラー 105により、再 度、 Z軸方向の共焦点位置「X2」において合焦点される。他方、 L1層に合焦点され た場合、 L2層からの迷光（図 13中の点線を参照）が、共焦点位置「X2」力も受光素 子に近い位置「XI」において集光される。尚、本発明に係る「一の戻り光」の他の具 体例が、「L1層に合焦点され、散乱又は反射された戻り光」によって構成されている 。また、本発明に係る「迷光」の一具体例が、「L1層に合焦点された場合における、 L 2層からの迷光」によって構成されている。 As shown in FIG. 13, in the finite optical system when focused on the L1 layer, the laser beam LB force is focused on the L1 layer by the actuator unit 109 and the objective lens 108 under the control of the CPU314. The focused, scattered or reflected return light is focused again at the confocal position “X2” in the Z-axis direction by the half mirror 105. On the other hand, when focused on the L1 layer, the stray light from the L2 layer (see the dotted line in FIG. 13) is collected at the position “XI” where the confocal position “X2” force is also close to the light receiving element. In addition, other components of “one return light” according to the present invention The body example is constituted by “return light focused on the L1 layer and scattered or reflected”. A specific example of “stray light” according to the present invention is configured by “stray light from the L2 layer when focused on the L1 layer”.
[0136] 以上のように、有限光学系においても、各記録層における集光点位置と、共焦点位 置とは、一般的に、一対一に夫々対応付けられている。この有限光学系に係る共焦 点光学系によれば、光路の設計の際に、部品点数の削減を実現することが可能であ る。 [0136] As described above, also in the finite optical system, the condensing point position and the confocal position in each recording layer are generally associated one-to-one. According to the confocal point optical system related to the finite optical system, it is possible to reduce the number of parts when designing the optical path.
[0137] 本発明は、上述した実施例に限られるものではなぐ請求の範囲及び明細書全体 力 読み取れる発明の要旨或いは思想に反しない範囲で適宜変更可能であり、その ような変更を伴う光ピックアップ及び情報機器もまた本発明の技術的範囲に含まれる ものである。  [0137] The present invention is not limited to the above-described embodiments, but can be appropriately changed within the scope of the claims and the entire specification without departing from the gist or concept of the invention which can be read, and an optical pickup with such a change. In addition, information devices are also included in the technical scope of the present invention.
産業上の利用可能性  Industrial applicability
[0138] 本発明に係る光ピックアップ及び情報機器は、例えば DVD等の情報記録媒体に 対してデータの記録又は再生を行う際にレーザ光を照射する光ピックアップに利用 可能であり、更に当該光ピックアップを備える情報機器に利用可能である。 The optical pickup and the information device according to the present invention can be used for an optical pickup that emits laser light when recording or reproducing data on, for example, an information recording medium such as a DVD. It can be used for information equipment provided with.

Claims

請求の範囲 The scope of the claims
[1] 複数の記録層を備える記録媒体に対するデータの記録及び再生のうち少なくとも 一方を行う光ピックアップであって、  [1] An optical pickup that performs at least one of data recording and reproduction on a recording medium having a plurality of recording layers,
レーザ光を照射する光源と、  A light source that emits laser light;
照射された前記レーザ光を、前記複数の記録層のうちの一の記録層に導く光学系 と、  An optical system for guiding the irradiated laser light to one recording layer of the plurality of recording layers;
導かれた前記レーザ光に起因して、前記複数の記録層にお！/ヽてそれぞれ反射す る戻り光を、受光する受光手段と、  Due to the guided laser beam, the plurality of recording layers! Light receiving means for receiving the return light that is reflected back and forth,
前記戻り光のうち少なくとも前記一の記録層において反射する一の戻り光を、選択 的に通過させ、前記受光手段に受光させる所定の開口部を有するピンホールと、 前記所定の開口部に前記一の戻り光を集光させる焦点可変レンズと、 前記一の戻り光を集光させるように、前記焦点可変レンズに所定の電圧を印加する 第 1制御手段と、  Of the return light, at least one return light reflected by the one recording layer is selectively allowed to pass through, and a pinhole having a predetermined opening for receiving the light by the light receiving means; and the one in the predetermined opening. A variable-focus lens that collects the return light, and a first control unit that applies a predetermined voltage to the variable-focus lens so as to collect the one return light;
を備えることを特徴とする光ピックアップ。  An optical pickup comprising:
[2] 前記所定の開口部と、前記受光手段との相対的な位置関係を制御する第 2制御手 段を更に備えることを特徴とする請求の範囲第 1項に記載の光ピックアップ。  [2] The optical pickup according to [1], further comprising a second control means for controlling a relative positional relationship between the predetermined opening and the light receiving means.
[3] 前記第 2制御手段は、光軸方向である Z軸方向、前記 Z軸方向と直交する X軸方向 、並びに、前記 Z軸方向及び前記 X軸方向と直交する Y軸方向に基づいて、前記相 対的な位置関係を制御することを特徴とする請求の範囲第 2項に記載の光ピックアツ プ。  [3] The second control means is based on a Z-axis direction which is an optical axis direction, an X-axis direction orthogonal to the Z-axis direction, and a Y-axis direction orthogonal to the Z-axis direction and the X-axis direction. 3. The optical pick-up according to claim 2, wherein the relative positional relationship is controlled.
[4] 複数の記録層を備える記録媒体に対するデータの記録及び再生のうち少なくとも 一方を行う光ピックアップであって、  [4] An optical pickup that performs at least one of data recording and reproduction on a recording medium having a plurality of recording layers,
レーザ光を照射する光源と、  A light source that emits laser light;
照射された前記レーザ光を、前記複数の記録層のうちの一の記録層に導く光学系 と、  An optical system for guiding the irradiated laser light to one recording layer of the plurality of recording layers;
導かれた前記レーザ光に起因して、前記複数の記録層にお！ヽてそれぞれ反射す る戻り光を、受光する受光手段と、  Due to the guided laser beam, the plurality of recording layers! A light receiving means for receiving the return light that is reflected in each case;
前記戻り光のうち少なくとも前記一の記録層において反射する一の戻り光を、選択 的に通過させ、前記受光手段に受光させる所定の開口部を有するピンホールと、 前記所定の開口部と、前記受光手段との光軸上での相対的な位置関係を制御す る第 2制御手段と、 Select one return light reflected from at least one recording layer among the return lights. A pinhole having a predetermined opening for allowing the light receiving means to receive light, and a second control for controlling a relative positional relationship between the predetermined opening and the light receiving means on the optical axis. Means,
受光された前記一の戻り光に基づいて、前記データに対応される RF信号を演算す る演算手段と、  An arithmetic means for calculating an RF signal corresponding to the data based on the one return light received;
を備えることを特徴とする光ピックアップ。  An optical pickup comprising:
[5] 前記所定の開口部に前記一の戻り光を集光させる焦点可変レンズと、 [5] A variable focus lens for condensing the one return light at the predetermined opening,
前記一の戻り光を集光させるように、前記焦点可変レンズに所定の電圧を印加する 第 1制御手段と、  First control means for applying a predetermined voltage to the variable focus lens so as to collect the one return light; and
を更に備えることを特徴とする請求の範囲第 4項に記載の光ピックアップ。  The optical pickup according to claim 4, further comprising:
[6] 前記受光手段は、前記一の戻り光を受光するための第 1受光素子を含み、 [6] The light receiving means includes a first light receiving element for receiving the one return light,
前記第 1制御手段は、前記第 1受光素子で受光された前記一の戻り光に基づいて 、前記所定の電圧を印加することを特徴とする請求の範囲第 1項に記載の光ピックァ ップ。  2. The optical pickup according to claim 1, wherein the first control means applies the predetermined voltage based on the one return light received by the first light receiving element. .
[7] 前記受光手段は、前記一の戻り光を受光するための第 1受光素子を含み、  [7] The light receiving means includes a first light receiving element for receiving the one return light,
前記第 2制御手段は、前記第 1受光素子で受光された前記一の戻り光に基づいて The second control means is based on the one return light received by the first light receiving element.
、前記所定の開口部と、前記受光手段との相対的な位置関係を制御することを特徴 とする請求の範囲第 2項に記載の光ピックアップ。 3. The optical pickup according to claim 2, wherein a relative positional relationship between the predetermined opening and the light receiving means is controlled.
[8] 前記受光手段は、前記第 1受光素子、及び導かれた前記レーザ光に起因して、前 記複数の記録層のうちの他の記録層において反射する迷光を受光するための第 2 受光素子を含み、 [8] The light receiving means receives the stray light reflected on the other recording layer among the plurality of recording layers due to the first light receiving element and the guided laser beam. Including a light receiving element,
前記第 1受光素子は、前記レーザ光の光軸から相対的に近くに配置され、前記第 2 受光素子は、前記光軸から相対的に遠くに配置されることを特徴とする請求の範囲 第 6項に記載の光ピックアップ。  The first light receiving element is disposed relatively close to the optical axis of the laser beam, and the second light receiving element is disposed relatively far from the optical axis. The optical pickup according to item 6.
[9] 前記ピンホールは、前記戻り光が照射される照射面において、前記一の戻り光を受 光するための第 3受光素子を有し、 [9] The pinhole has a third light receiving element for receiving the one return light on an irradiation surface irradiated with the return light,
前記第 1制御手段は、前記第 3受光素子で受光された前記一の戻り光に基づいて 、前記所定の電圧を印加することを特徴とする請求の範囲第 1項に記載の光ピックァ ップ。 The optical picker according to claim 1, wherein the first control means applies the predetermined voltage based on the one return light received by the third light receiving element. Up.
[10] 前記ピンホールは、前記戻り光が照射される照射面において、前記一の戻り光を受 光するための第 3受光素子を有し、  [10] The pinhole has a third light receiving element for receiving the one return light on an irradiation surface irradiated with the return light,
前記第 2制御手段は、前記第 3受光素子で受光された前記一の戻り光に基づいて The second control means is based on the one return light received by the third light receiving element.
、前記所定の開口部と、前記受光手段との相対的な位置関係を制御することを特徴 とする請求の範囲第 2項に記載の光ピックアップ。 3. The optical pickup according to claim 2, wherein a relative positional relationship between the predetermined opening and the light receiving means is controlled.
[11] 前記ピンホールは、前記戻り光が照射される照射面において、前記第 3受光素子、 及び導かれた前記レーザ光に起因して、前記複数の記録層のうちの他の記録層に おいて反射する迷光を受光するための第 4受光素子を少なくとも有し、 [11] The pinhole is formed on the other recording layer of the plurality of recording layers due to the third light receiving element and the guided laser beam on the irradiation surface irradiated with the return light. At least a fourth light receiving element for receiving the stray light that is reflected
前記第 3受光素子は、前記レーザ光の光軸から相対的に近くに配置され、前記第 4 受光素子は、前記光軸から相対的に遠くに配置されることを特徴とする請求の範囲 第 9項に記載の光ピックアップ。  The third light receiving element is disposed relatively close to the optical axis of the laser beam, and the fourth light receiving element is disposed relatively far from the optical axis. The optical pickup according to item 9.
[12] 受光された前記一の戻り光に基づいて、前記データに対応される RF信号を演算す る演算手段を更に備え、 [12] The apparatus further comprises computing means for computing an RF signal corresponding to the data based on the received return light.
前記一の戻り光に対応される一の信号成分と、前記複数の記録層のうちの他の記 録層にお 1ヽて反射する迷光に対応される他の信号成分との差分に基づ!ヽて、演算 係数を算出し、前記演算係数に基づいて、前記 RF信号を演算するように、前記演算 手段を制御する第 3制御手段を更に備えることを特徴とする請求の範囲第 1項に記 載の光ピックアップ。  Based on a difference between one signal component corresponding to the one return light and another signal component corresponding to stray light reflected on the other recording layer of the plurality of recording layers. The apparatus further comprises third control means for controlling the calculation means so as to calculate a calculation coefficient and calculate the RF signal based on the calculation coefficient. The optical pickup described in 1.
[13] 前記受光手段の形状及び面積は、前記光学系、又は前記所定の開口部における 光学的な特性、又は物理的な特性に基づ 、て規定されることを特徴とする請求の範 囲第 1項に記載の光ピックアップ。  [13] The shape and area of the light receiving means are defined based on optical characteristics or physical characteristics of the optical system or the predetermined opening. The optical pickup according to item 1.
[14] 前記受光手段は、線対称又は点対称に、少なくとも 2分割されていることを特徴とす る請求の範囲第 1項に記載の光ピックアップ。 14. The optical pickup according to claim 1, wherein the light receiving means is divided into at least two parts in line symmetry or point symmetry.
[15] 請求の範囲第 1項に記載の光ピックアップと、 [15] The optical pickup according to claim 1;
前記レーザ光を前記光ディスクに照射することで、前記データの記録又は再生を行 う記録再生手段と  A recording / reproducing means for recording or reproducing the data by irradiating the optical disc with the laser beam;
を備えることを特徴とする情報機器。  An information device comprising:
PCT/JP2007/057208 2006-03-31 2007-03-30 Optical pickup and information device WO2007114372A1 (en)

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