JP2009009634A - Optical pickup, optical information recording device, optical information recording method, optical information reproducing device, optical information reproducing method, and optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup, an optical information recording device, and an optical information recording method which can record or reproduce information stably with simple constitution. <P>SOLUTION: An objective lens 40 is driven so that a servo light beam Ls1 is focused for a reflection film 104 reflecting at least a part of a light beam Lb0 formed on an optical disk 100 in which a record mark RM is formed by dividing a light beam LB0 into a light beam Lb1 and a servo light beam Ls1 and projecting a light beam Lb1, by changing a convergence state of the light beam Lb1, the light beam Lb1 is made to project to a position being different from a servo focus Fs of the servo light beam Ls1 in the depth direction through the objective lens 40. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical pickup, an optical information recording apparatus, an optical information recording method, an optical information reproducing apparatus, an optical information reproducing method, and an optical information recording medium. For example, information is recorded on a recording medium using a light beam. The present invention is suitable for use in an optical information recording / reproducing apparatus that reproduces the information from the recording medium.

  Conventionally, as an optical information recording / reproducing apparatus, an optical disk apparatus using a disk-shaped optical disk as an information recording medium has been widely used. As an information recording medium, a CD (Compact Disc), a DVD (Digital Versatile Disc), and a Blu are generally used. -Ray Disc (registered trademark, hereinafter referred to as BD) or the like is used.

  In such an optical disc apparatus, various kinds of information such as various contents such as music contents and video contents, or various data for a computer are recorded on the optical disc. In particular, in recent years, the amount of information has increased due to higher definition of video and higher sound quality of music, and an increase in the number of contents to be recorded on one optical disc has been demanded. It has been demanded.

Therefore, as one of the techniques for increasing the capacity of an optical disk, there has been proposed one in which information is recorded by forming a minute hologram in a recording medium by interfering with two light beams. (For example, refer to Patent Document 1).
JP 2006-78834 A (FIG. 1)

  However, the optical disc apparatus having such a configuration requires high-level control such that the focal positions of two types of light beams are simultaneously adjusted at a location where information on the rotating and vibrating optical disc is to be recorded, and the configuration becomes complicated and stable. There is a problem that it is difficult to record or reproduce the recorded information.

  The present invention has been made in consideration of the above points, and an optical pickup, an optical information recording apparatus, an optical information recording method, an optical information reproducing apparatus, and an optical information capable of stably recording or reproducing information with a simple configuration. A reproduction method and an optical information recording medium capable of stably recording or reproducing information are proposed.

  In order to solve this problem, in the present invention, an optical pickup that irradiates an optical information recording medium on which a recording mark is formed by irradiating light having a predetermined intensity or more with emitted light emitted from a light source. A first light separation unit that separates the emitted light into a first light and a second light, an objective lens that collects the first light and the second light and irradiates the optical information recording medium; An objective lens driving unit that drives the objective lens to focus the second light on a reflective layer that is formed on the optical information recording medium and reflects at least a part of the second light, and convergence of the first light By changing the state, the focal point of the first light is separated from the focal point of the second light by an arbitrary distance in the depth direction in which the objective lens approaches and separates from the optical information recording medium. Target depth at which the first light should be irradiated with the focus of light Was provided a focus movement unit to match the.

  Thereby, it is possible to perform recording or reading of information with respect to the optical information recording medium by irradiating the first light, so that it is not necessary to provide two optical paths corresponding to two kinds of beams, and one kind of light. Optical components can be omitted for the amount of the beam, and advanced control such as adjusting the focal positions of the two types of light beams at the same time is not necessary, and the optical components necessary for the control can be omitted.

  Furthermore, in the present invention, when irradiating the emitted light emitted from the light source to the optical information recording medium on which the recording mark is formed by irradiating the light having a predetermined intensity or more, the emitted light is changed to the first light. The light is separated into the light and the second light, and the first light and the second light having the intensity or higher are collected and irradiated to the optical information recording medium, and formed on the optical information recording medium. The objective lens is moved closer to the optical information recording medium by driving the objective lens so as to focus the second light on the reflective layer that reflects at least a part thereof, and changing the convergence state of the first light. In the depth direction, the focus of the first light is separated from the focus of the second light by an arbitrary distance, and the focus of the first light is set to a target depth to be irradiated with the first light. I tried to match.

  Thereby, since the recording mark can be formed by irradiating the first light, it is not necessary to provide two optical paths corresponding to the two types of beams, and the optical components can be omitted by one type of the light beams. In addition, advanced control such as adjusting the focal positions of the two types of light beams at the same time is unnecessary, and optical components necessary for the control can be omitted.

  In the present invention, when irradiating the light emitted from the light source to the optical information recording medium on which the recording mark is formed by irradiating the light having a predetermined intensity or more, the emitted light is changed to the first light. The light is separated into light and second light, the first light and the second light are collected and irradiated onto the optical information recording medium, and formed on the optical information recording medium, and reflects at least part of the second light. The depth at which the objective lens approaches and separates from the optical information recording medium by driving the objective lens so as to focus the second light on the reflecting layer and changing the convergence state of the first light. A focal point moving unit that, in a direction, separates the focal point of the first light from the focal point of the second light by an arbitrary distance, and adjusts the focal point of the first light to a target depth to be irradiated with the first light; The reflected light beam formed by reflecting the first light on the recording mark is received.

  As a result, information can be read from the optical information recording medium based on the reflected light beam generated by irradiating the first light, so there is no need to provide two optical paths corresponding to the two types of beams. Optical components can be omitted for the number of types of light beams, and advanced control such as adjusting the focal positions of the two types of light beams at the same time is unnecessary, and optical components necessary for the control can be omitted. .

  Further, in the present invention, a resin having an organometallic compound and having photoreactivity is cured by a photoreaction caused by irradiation with a predetermined initialization light, and the predetermined recording light is condensed when information is recorded. As a result, the temperature in the vicinity of the focal point of the recording light rises, the organometallic compound is altered to form a recording mark, and the information is based on the return light in response to irradiation with a predetermined reading light during information reproduction. And a reflection layer that reflects at least a part of servo light having the same wavelength as that of the recording light irradiated to adjust the position of the recording light in the recording layer to an arbitrary position.

  Thereby, a recording mark can be formed on the recording layer by light irradiation, and the position of the recording mark in the depth direction can be determined by the servo light with reference to the reflective layer.

  According to the present invention, it is possible to perform recording or reading of information on the optical information recording medium by irradiating the first light. Therefore, it is not necessary to provide two optical paths corresponding to two types of beams. Optical components can be omitted for the different types of light beams, and advanced control such as adjusting the focal positions of the two types of light beams at the same time is unnecessary, and optical components necessary for the control can be omitted. Thus, it is possible to realize an optical pickup capable of stably recording or reproducing information with a simple configuration.

  Further, according to the present invention, since the recording mark can be formed by irradiating the first light, it is not necessary to provide two optical paths corresponding to the two types of beams, and an optical component is provided for one type of light beam. In addition, it is not necessary to perform advanced control such as adjusting the focal positions of two types of light beams at the same time, and optical components necessary for the control can be omitted. Thus, information can be stably provided with a simple configuration. An optical information recording apparatus and an optical information recording method capable of recording or reproducing data can be realized.

  Furthermore, according to the present invention, since information can be read from the optical information recording medium based on the reflected light beam generated by irradiating the first light, it is necessary to provide two optical paths corresponding to the two types of beams. The optical components can be omitted for one type of light beam, and advanced control such as adjusting the focal positions of the two types of light beams at the same time is unnecessary, and the optical components required for the control are omitted. Thus, it is possible to realize an optical information reproducing apparatus and an optical information reproducing method capable of stably recording or reproducing information with a simple configuration.

  Furthermore, according to the present invention, the recording mark can be formed on the recording layer by light irradiation, and the position of the recording mark in the depth direction can be determined by the servo light with reference to the reflective layer, and thus stable. In addition, an optical information recording medium capable of recording or reproducing information can be realized.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) Configuration of Optical Disc (1-1) Layer Structure of Optical Disc First, an optical disc 100 used as an optical information recording medium in the present invention will be described. As shown in the external view in FIG. 1, the optical disc 100 as a whole is formed in a disk shape having a diameter of about 120 [mm], similar to the conventional CD, DVD, and BD, and a hole 100H is formed in the central portion. ing.

  Further, as shown in the cross-sectional view of FIG. 2, the optical disc 100 has a recording layer 101 for recording information in the center, and is configured so that the recording layer 101 is sandwiched from both sides by substrates 102 and 103. Yes.

  Incidentally, the thickness t1 of the recording layer 101 is about 0.3 [mm], and the thicknesses t2 and t3 of the substrates 102 and 103 are both about 0.6 [mm].

  The substrates 102 and 103 are made of, for example, a material such as polycarbonate or glass, and both of them transmit light incident from one surface to the opposite surface with high transmittance. Further, the substrates 102 and 103 have a certain degree of strength and play a role of protecting the recording layer 101. In addition, about the surface of the board | substrates 102 and 103, unnecessary reflection may be made to be prevented by anti-reflective coating.

  The optical disc 100 also has a reflective film 104 as a reflective layer on the boundary surface between the recording layer 101 and the substrate 103. The reflective film 104 is made of a dielectric multilayer film or the like, and reflects the servo light beam Ls1 made of blue laser light having a wavelength of 405 [nm] used for reproduction processing and recording processing.

  The reflection film 104 forms a guide groove for tracking servo. Specifically, a spiral track is formed by lands and grooves similar to a general BD-R (Recordable) disk or the like. . This track is given an address consisting of a series of numbers for each predetermined recording unit, and the track on which information is recorded or reproduced can be specified by the address.

  Note that pits or the like may be formed on the reflective film 104 (that is, the boundary surface between the recording layer 101 and the substrate 103) instead of the guide grooves, or the guide grooves and pits may be combined.

  When the servo light beam Ls1 is irradiated from the substrate 102 side, the reflection film 104 reflects this toward the substrate 102 side. Hereinafter, the light beam reflected at this time is referred to as a servo reflected light beam Ls2.

  The servo reflected light beam Ls2 is used to align the servo light focus Fs of the servo light beam Ls1 collected by a predetermined objective lens OL with a target track (hereinafter referred to as a target track) in an optical disc apparatus, for example. It is assumed that it is used for position control of the objective lens OL (that is, focus control and tracking control).

  In practice, when information is recorded on the optical disc 100, the servo light beam Ls1 is condensed by the position-controlled objective lens OL and focused on the target track of the reflective film 104 as shown in FIG.

  In addition, the light beam Lb1 made of blue laser light having a wavelength of 405 [nm], which is shared by the servo light beam Ls1 and the optical axis Lx and is collected by the objective lens OL1, passes through the substrate 102 and in the recording layer 101. A position corresponding to the desired track is focused. At this time, the focal point Fb of the light beam Lb1 is located closer to the servo light focal point Fs on the common optical axis Lx with respect to the objective lens OL, that is, on the “near side”.

  At this time, in the recording layer 101, when the light beam Lb1 is the recording light beam Lb1w used during the recording process, the portion where the recording light beam Lb1w is condensed and has a predetermined intensity or more (that is, A recording mark RM is formed around the focal point Fb. For example, when the wavelength λ of the light beam Lb is 405 [nm], the numerical aperture NA of the objective lens OL is 0.5, and the refractive index n of the objective lens OL is 1.5, the diameter RMr = 1 [μm. ], A recording mark RM having a height RMh = 10 [μm] is formed.

  Further, the optical disc 100 is designed such that the thickness t1 (= 0.3 [mm]) of the recording layer 101 is sufficiently larger than the height RMh of the recording mark RM. For this reason, the optical disc 100 records the recording mark RM while switching the distance from the recording reflective film 104 in the recording layer 101 (hereinafter referred to as the depth), so that FIGS. As shown in FIG. 2, multilayer recording can be performed in which a plurality of mark recording layers are stacked in the thickness direction of the optical disc 100.

  In this case, the depth of the recording mark RM is changed by adjusting the depth of the focal point Fb of the recording light beam Lb1w in the recording layer 101 of the optical disc 100. For example, in the optical disc 100, when the distance p3 between the mark recording layers is set to about 15 [μm] in consideration of the mutual interference between the recording marks RM, about 20 mark recording layers are formed in the recording layer 101. can do. The distance p3 may be set to various values other than about 15 [μm] in consideration of the mutual interference between the recording marks RM.

  On the other hand, when the information is reproduced, the optical disc 100 is focused so that the servo light beam Ls1 collected by the objective lens OL1 is focused on the target track of the reflective film 104, as in the case of recording the information. The position of the objective lens OL is controlled.

  Further, in the optical disc 100, a position where the focal point Fb of the reading light beam Lb1r condensed through the same objective lens OL corresponds to the “front side” of the target track in the recording layer 101 and becomes the target depth. (Hereinafter, this is referred to as a target mark position).

  At this time, the recording mark RM recorded at the position of the focal point Fb reflects the reading light beam Lb1r due to the difference in refractive index from the surroundings, and the reflected light beam is reflected from the recording mark RM recorded at the target mark position. Lb2 is generated.

  As described above, the optical disc 100 uses the servo light beam Ls1 for position control and the light beam Lb1w for recording when information is recorded, so that the position where the focal point Fb is irradiated in the recording layer 101, that is, the reflective film. A recording mark RM is formed as the information at a target mark position in front of the target track in 104 and at a target depth.

  In addition, when recorded information is reproduced, the optical disc 100 uses the servo light beam Ls1 for position control and the read light beam Lb1r to record data recorded at the position of the focus Fb, that is, the target mark position. A reflected light beam Lb2 is generated from the mark RM.

(1-2) Configuration of Recording Layer Next, the configuration of the recording layer 101 described above will be described.

  As shown in FIG. 4, the recording layer 101 is made of a photopolymerizable photopolymer, and an uncured resin 101a made of a uniformly dispersed monomer and a photopolymerization initiator is sandwiched between the substrates 102 and 103. For example, the initialization light Lp1 is irradiated from an initialization light source 110 made of a high pressure mercury lamp, a high pressure meta-hara lamp, a solid laser, a semiconductor laser, or the like, and the uncured resin 101a is polymerized.

  The uncured resin 101a is composed of, for example, a radical polymerization compound and a photopolymerization initiator, or is composed of a cation polymerization compound and a cation generation type photopolymerization initiator. In addition, the photopolymerizable resin, photocrosslinkable resin, and photopolymerization initiator, of which the photopolymerization initiator, in particular, adjusts the wavelength at which photopolymerization easily occurs to a desired wavelength by appropriately selecting the material. It is possible.

  Further, a small amount of an organometallic compound and / or an inorganic metal compound is mixed in the uncured resin 101a, and a photopolymerization reaction, a photocrosslinking reaction, or both reactions are caused by irradiation with the initialization light Lp1. Has been made.

  As described above, the optical disc 100 is formed in a thin plate shape as a whole and is configured to substantially transmit light. The resin in the recording layer 101 is polymerized and / or crosslinked by the initialization process, and further, the recording layer A small amount of an organometallic compound is contained in 101.

  In the recording layer 101, when a light beam Lb1 having a predetermined intensity or more at the time of recording processing is condensed at a target mark position in the recording layer 101, a recording mark RM is formed. This is because the light beam Lb1 is condensed in the recording layer 101 and the temperature locally rises, whereby the organometallic compound is thermally changed and denatured, and a metal compound such as fluoride or oxide, or pure It is considered that a new metal is precipitated and agglomerated.

  That is, in the recording layer 101, the portion of the resin containing the organometallic compound that has been locally heated to a high temperature by condensing the recording light beam Lb1w is altered, and the metal compound or pure metal is deposited. It is assumed that the refractive index changes and the reflectance is improved.

  In practice, the uncured resin 101a is, for example, an acrylic ester monomer (p-cumylphenol ethylene oxide-added acrylic ester) and a urethane bifunctional acrylate oligomer of 40:60 (weight ratio) and an oligomer weight ratio of 2%. (Bis (η-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium, which is a metal compound and a photopolymerization initiator) (Ciba Specialty Chemicals Irg-784, hereinafter referred to as Irg-784) is produced by mixing and degassing in a dark room.

The recording layer 101 is sandwiched between the substrate 102 and the substrate 103 on which the reflective film 104 is formed in a state where the uncured resin 101a is spread on the substrate 102, and then initialized by a high-pressure mercury lamp. It is produced by irradiating 60 [min] of initialization light Lp1 (with a power density of 30 mW / cm ^{2 at a} wavelength of 365 [nm]) by the light source 110 and photocuring.

  In this initialization process, the recording layer 101 is initialized (precured) when the resin undergoes polymerization, crosslinking, or both in the interior due to the occurrence of a photopolymerization reaction and / or a photocrosslinking reaction as a whole. The As a result, the refractive index of the recording layer 101 changes as a whole as compared with that before irradiation of the initialization light. Incidentally, the recording layer 101 is almost transparent in the photocured state, and transmits the irradiated light at a high rate.

  Thus, in the vicinity of the target position in the recording layer 101, when the recording light beam Lb1w is condensed and locally heated, a recording mark RM having a portion having a locally higher reflectance than the surrounding area is formed. Will be formed and information will be recorded. As a result, when the read light beam Lb1r is irradiated to the recording mark RM, the reflected light beam Lb2 having high luminance can be detected. Incidentally, it is difficult to visually confirm the recording mark RM.

  On the other hand, when the reading light beam Lb1r is irradiated to a portion where the recording mark RM is not recorded (that is, an unrecorded portion), a very weak reflected light beam Lb2 is detected. That is, when the optical information recording / reproducing apparatus 20 reproduces information from the optical disc 100, it can be seen that the detected intensity of the reflected light beam Lb2 varies greatly depending on the presence or absence of the recording mark RM.

  This is because, for example, the optical disk apparatus 20 can record information on the optical disk 100 by associating the code “0” or “1” with the presence or absence of the recording mark RM, and when the information is reproduced, the target position at that time This indicates that it is possible to determine with high accuracy whether or not the recording mark RM is recorded, that is, whether the code “0” or “1” is recorded as information.

  As described above, the optical disc apparatus 20 uses the optical disc 100 to focus the recording light beam Lb1w on the recording layer 101 in which the organometallic compound is blended and is photocured in advance to increase the temperature. Information recording in which pure metal is deposited to form the recording mark RM can be performed. In addition, the optical disc apparatus 20 can perform information reproduction by detecting the reflected light beam Lb2 having a high luminance by irradiating the recording mark RM with the reading light beam Lb1r.

(2) Configuration of Optical Disc Device Next, the optical disc device 20 corresponding to the optical disc 100 described above will be described. As shown in FIG. 5, the optical disc apparatus 20 is configured to perform overall control by a control unit 21.

  The control unit 21 is mainly configured by a CPU (Central Processing Unit) (not shown), reads various programs such as a basic program and an information recording program from a ROM (Read Only Memory) (not shown), and stores them in a RAM (Random) (not shown). Various processes such as an information recording process are executed by expanding in (Access Memory).

  For example, when the control unit 21 receives an information recording command, recording information, and recording address information from an external device (not shown) with the optical disc 100 loaded, the control unit 21 supplies the driving command and recording address information to the driving control unit 22. The recording information is supplied to the signal processing unit 23. Incidentally, the recording address information is information indicating an address at which the recording information is to be recorded among the addresses given to the recording layer 101 of the optical disc 100.

  The drive control unit 22 drives and controls the spindle motor 24 in accordance with the drive command to rotate the optical disc 100 at a predetermined rotation speed, and controls the sled motor 25 to drive the optical pickup 26 with the moving shafts 25A and 25B. Are moved to a position corresponding to the recording address information in the radial direction of the optical disc 100 (that is, the inner circumferential direction or the outer circumferential direction).

  The signal processing unit 23 generates a recording signal by performing various signal processing such as predetermined encoding processing and modulation processing on the supplied recording information, and supplies the recording signal to the optical pickup 26.

  The optical pickup 26 performs focus control and tracking control based on the control of the drive control unit 22 (FIG. 4), so that a track indicated by recording address information in the recording layer 101 of the optical disc 100 (hereinafter referred to as a target track). The recording mark RM is recorded in accordance with the recording signal from the signal processing unit 23 (details will be described later).

  When the control unit 21 receives, for example, an information reproduction command and reproduction address information indicating the address of the recording information from an external device (not shown), the control unit 21 supplies the drive command to the drive control unit 22 and also reproduces the reproduction processing command. Is supplied to the signal processing unit 23.

  As in the case of recording information, the drive control unit 22 controls the spindle motor 24 to rotate the optical disc 100 at a predetermined rotational speed, and controls the sled motor 25 to control the optical pickup 26 for reproduction addressing. Move to a position corresponding to the information.

  The optical pickup 26 performs focus control and tracking control based on the control of the drive control unit 22 (FIG. 4), thereby reading out the track indicated by the reproduction address information (that is, the target track) in the recording layer 101 of the optical disc 100. The irradiation position of the light beam Lb1r is aligned, and a light beam having a predetermined light amount is irradiated. At this time, the optical pickup 26 detects the reflected light beam Lb2 generated from the recording mark RM of the recording layer 101 in the optical disc 100, and supplies a detection signal corresponding to the amount of light to the signal processing unit 23 ( Details will be described later).

  The signal processing unit 23 generates reproduction information by performing various signal processing such as predetermined demodulation processing and decoding processing on the supplied detection signal, and supplies the reproduction information to the control unit 21. In response to this, the control unit 21 sends the reproduction information to an external device (not shown).

  As described above, the optical disc apparatus 20 controls the optical pickup 26 by the control unit 21 to record information at the target mark position in the recording layer 101 of the optical disc 100 and reproduce information from the target mark position. ing.

(3) Configuration of Optical Pickup Next, the configuration of the optical pickup 26 will be described. As shown in FIG. 6, the optical pickup 26 has a servo optical system 30 for servo control and an information optical system 50 for reproducing or recording information.

  The optical pickup 26 separates the light beam Lb0 emitted from the laser diode 31 into a servo light beam Ls1 and a light beam Lb1 (reading light beam Lb1r or recording light beam Lb1w) by the polarization beam splitter 34. The optical pick-up 26 is adapted to make the servo light beam Ls1 and the light beam Lb1 enter the same objective lens 40 via the servo optical system 30 and the information optical system 50, respectively, and irradiate the optical disc 100, respectively.

  That is, the laser diode 31 can emit blue laser light having a wavelength of about 405 [nm]. In practice, the laser diode 31 emits a light beam Lb0 having a predetermined amount of light, which is a divergent light, based on the control of the control unit 21 (FIG. 5) and makes it incident on the collimator lens 32. The collimator lens 32 converts the light beam Lb0 from diverging light to parallel light and makes it incident on the half-wave plate 33.

  The polarization direction of the light beam Lb0 is rotated by a predetermined angle by the half-wave plate 33, so that, for example, the p-polarized component is approximately 80% and the s-polarized component is approximately 20%. 34S.

  The polarization beam splitter 34 reflects or transmits the light beam on the reflection / transmission surface 34S at a different rate depending on the polarization direction of the light beam Lb0. For example, the reflection / transmission surface 34S transmits almost all the p-polarized light beam and reflects almost all the s-polarized light beam.

  The polarization beam splitter 34 reflects the light beam Lb0 made of s-polarized light as the servo light beam Ls1, and transmits the light beam Lb0 made of p-polarized light as the light beam Lb1.

(3-1) Optical Path of Servo Light Beam As shown in FIG. 7, the servo optical system 30 irradiates the optical disk 100 with the servo light beam Ls1 separated by the polarization beam splitter 34 through the objective lens 40, and The servo reflected light beam Ls2 reflected by the optical disc 100 is received by the photodetector 43.

  That is, in the servo optical system 30, the servo light beam Ls 1 reflected by the polarization beam splitter 34 enters the polarization beam splitter 36. The polarization beam splitter 36 reflects the servo light beam Ls 1 composed of s-polarized light and makes the servo light beam Ls 1 incident on the quarter-wave plate 37.

  The quarter-wave plate 37 converts the servo light beam Ls1 composed of s-polarized light into, for example, left-circularly polarized light and enters the non-polarized beam splitter 38. The non-polarizing beam splitter 38 is configured to transmit and reflect the light beam at a rate of about 50%, for example, so that the servo light beam Ls1 is reflected and incident on the objective lens 40.

  The objective lens 40 collects the servo light beam Ls1 and irradiates it toward the reflective film 104 of the optical disc 100. At this time, as shown in FIG. 2, the servo light beam Ls1 passes through the substrate 102 and the recording layer 101 and is reflected by the reflective film 104, and travels in the opposite direction to the servo light beam Ls1. The servo reflected light beam Ls2 is as follows.

  Thereafter, the servo reflected light beam Ls2 is converted into parallel light by the objective lens 40 and then incident on the non-polarizing beam splitter 38. The non-polarizing beam splitter 38 reflects the servo reflected light beam Ls <b> 2 at a ratio of about 50% by the reflection / transmission surface 38 </ b> S and makes it incident on the quarter-wave plate 37.

  The quarter-wave plate 37 converts the servo reflected light beam Ls2 composed of right-handed circularly polarized light into p-polarized light, and enters the polarizing beam splitter 36. The polarization beam splitter 36 transmits the servo reflected light beam Ls 2 made of p-polarized light and enters the multi-lens 41.

  The multi-lens 41 converges the servo reflected light beam Ls2 and gives astigmatism by the cylindrical lens 42, and then irradiates the photodetector 43 with the servo reflected light beam Ls2.

  By the way, in the optical disc apparatus 20, since the surface blur etc. in the rotating optical disc 100 may occur, the relative position of the target track with respect to the objective lens 40 may vary.

  For this reason, in order to cause the servo light focus Fs (FIG. 2) of the servo light beam Ls1 to follow the target track, the servo focus Fs is in a focus direction that is a close direction or a separation direction with respect to the optical disc 100 and an inner peripheral side direction of the optical disc 100. Alternatively, it is necessary to move in the tracking direction which is the outer peripheral side direction.

  Therefore, the objective lens 40 can be driven in the biaxial direction of the focus direction and the tracking direction by the biaxial actuator 40A.

  In the servo optical system 30 (FIG. 7), the focused state when the servo light beam Ls1 is collected by the objective lens 38 and applied to the reflection film 104 of the optical disc 100 is in the focused state. The optical positions of the various optical components are adjusted so as to be reflected in the focused state when the light is condensed and irradiated onto the photodetector 43.

  As shown in FIG. 8, the photodetector 43 has four detection areas 43A, 43B, 43C, and 43D that are divided in a lattice pattern on the surface irradiated with the servo reflected light beam Ls2. Incidentally, the direction (vertical direction in the figure) indicated by the arrow a1 corresponds to the traveling direction of the track when the servo light beam Ls1 is applied to the reflective film 104 (FIG. 3).

  The photodetector 43 detects a part of the servo reflected light beam Ls2 by the detection areas 43A, 43B, 43C, and 43D, respectively, and generates detection signals SDAs, SDBs, SDCs, and SDDs according to the detected light amount, respectively. These are sent to the signal processing unit 23 (FIG. 4).

  The signal processing unit 23 performs focus control by a so-called astigmatism method, calculates a focus error signal SFEs according to the following equation (1), and supplies this to the drive control unit 22.

  The focus error signal SFEs represents the amount of deviation between the servo light focus Fs of the servo light beam Ls1 and the reflective film 104 of the optical disc 100.

  The signal processing unit 23 performs tracking control by a so-called push-pull method, calculates a tracking error signal STEs according to the following equation (2), and supplies the tracking error signal STEs to the drive control unit 22.

  The tracking error signal STEs represents the amount of deviation between the servo light focus Fs and the target track on the reflective film 104 of the optical disc 100.

  The drive control unit 22 generates a focus drive signal SFDs based on the focus error signal SFEs, and supplies the focus drive signal SFDs to the biaxial actuator 40A, so that the servo light beam Ls1 is aligned with the reflective film 104 of the optical disc 100. The objective lens 40 is feedback-controlled (that is, focus control) so as to focus.

  Further, the drive control unit 22 generates a tracking drive signal STDs based on the tracking error signal STEs, and supplies the tracking drive signal STDs to the biaxial actuator 40A, whereby the servo light beam Ls1 is reflected on the reflective film 104 of the optical disc 100. The objective lens 40 is feedback controlled (that is, tracking control) so as to focus on the target track.

  Thus, the servo optical system 30 irradiates the reflection film 104 of the optical disc 100 with the servo light beam Ls1 and supplies the light reception result of the servo reflected light beam Ls2 that is the reflected light to the signal processing unit 23. . In response to this, the drive control unit 22 performs focus control and tracking control of the objective lens 40 so that the servo light beam Ls1 is focused on the target track of the reflective film 104.

(3-2) Optical Path of Light Beam On the other hand, in the information optical system 30, as shown in FIG. 9 corresponding to FIG. 6, the optical beam 100 is irradiated to the optical disc 100 through the objective lens 40 and reflected on the optical disc 100. The reflected light beam Lb2 thus formed is received by the photodetector 59.

  That is, in the information optical system 50, the light beam Lb1 transmitted through the polarization beam splitter 34 is incident on the quarter wavelength plate 52 via an LCP (Liquid Crystal Panel) 51 that corrects spherical aberration and the like.

  The quarter-wave plate 52 converts the light beam Lb1 from p-polarized light to, for example, right-circularly polarized light and enters the relay lens 53.

  The relay lens 53 converts the light beam Lb1 from parallel light into convergent light by the movable lens 53A, converts the light beam Lb1 that has become divergent light after convergence into the convergent light again by the fixed lens 53B, and makes it incident on the mirror 54. .

  Here, the movable lens 53A is moved in the optical axis direction of the light beam Lb1 by an actuator (not shown). In practice, the relay lens 53 can change the convergence state of the light beam Lb1 emitted from the fixed lens 53B by moving the movable lens 53A by an actuator based on the control of the control unit 21 (FIG. 5). ing.

  The mirror 54 reflects the light beam Lb1, thereby reversing the polarization direction of the circularly polarized light beam Lb1 (for example, from right circularly polarized light to left circularly polarized light) and deflecting the traveling direction thereof, thereby providing a non-polarizing beam splitter. 38 is incident. The non-polarizing beam splitter 38 transmits about 50% of the light beam Lb1 through the reflection / transmission surface 38S, and enters the objective lens 40.

  The objective lens 40 collects the light beam Lb1 and irradiates the optical disc 100 with it. At this time, the light beam Lb1 passes through the substrate 102 and is focused in the recording layer 101 as shown in FIG.

  Here, the position of the focal point Fb of the light beam Lb1 is determined by the convergence state when the light beam Lb1 is emitted from the fixed lens 53B of the relay lens 53. That is, the focal point Fb moves in the focusing direction in the recording layer 101 according to the position of the movable lens 53A.

  Specifically, the information optical system 50 is designed so that the moving distance of the movable lens 53A and the moving distance of the focal point Fb of the light beam Lb1 are substantially proportional to each other. For example, the movable lens 53A is moved by 1 [mm]. The focal point Fb of the light beam Lb1 is moved by 30 [μm].

  In practice, in the information optical system 50, the depth of the focal point Fb (FIG. 2) of the light beam Lb1 in the recording layer 101 of the optical disc 100 is controlled by the control unit 21 (FIG. 5) controlling the position of the movable lens 53A. d1 (that is, the distance from the reflective film 104) is adjusted so that the focal point Fb matches the target mark position.

  In this way, the information optical system 50 irradiates the light beam Lb1 through the servo-controlled objective lens 40 by the servo optical system 30, thereby matching the tracking direction of the focal point Fb of the light beam Lb1 with the target mark position, Further, by adjusting the depth d1 of the focal point Fb in accordance with the position of the movable lens 53A in the relay lens 53, the focus direction of the focal point Fb is made to coincide with the target mark position.

  The light beam Lb1 is condensed at the focal point Fb by the objective lens 40 during the recording process for recording information on the optical disc 100, and forms a recording mark RM at the focal point Fb.

  On the other hand, when the recording mark RM is recorded at the focal point Fb during the reproduction process for reading the information recorded on the optical disc 100, the light beam Lb1 is read from the reading light beam Fb1r condensed at the focal point Fb. The light is reflected as a reflected light beam Lb2 by the RM and enters the objective lens 40. At this time, the reflection direction of the circularly polarized light of the reflected light beam Lb2 is reversed (for example, from left circularly polarized light to right circularly polarized light) due to reflection by the recording mark RM.

  On the other hand, when the recording mark RM is not recorded at the focal point Fb, the light beam Lb1 diverges again after converging at the focal point Fb, is reflected by the reflective film 104, and enters the objective lens 40 as a reflected light beam Lb2. . At this time, the reflected light beam Lb2 is reflected by the reflecting film 104 so that the rotation direction of the circularly polarized light is reversed (for example, from left circularly polarized light to right circularly polarized light).

  The objective lens 40 converges the reflected light beam Lb2 to some extent, and enters the non-polarizing beam splitter 38. The non-polarizing beam splitter 38 transmits about 50% of the reflected light beam Lb 2 and enters the mirror 54.

  The mirror 54 reflects the reflected light beam Lb2, thereby inverting the polarization direction of the circularly polarized light beam Lb1 (for example, from right circularly polarized light to left circularly polarized light) and deflecting the traveling direction thereof, so that the relay lens 53 Incident to

  The relay lens 53 converts the reflected light beam Lb <b> 2 into parallel light and enters the quarter wavelength plate 52. The quarter wavelength plate 52 converts the reflected light beam Lb2 made of circularly polarized light into linearly polarized light (for example, left circularly polarized light to s polarized light), and enters the polarizing beam splitter 34 via the LCP 51.

  The polarization beam splitter 34 reflects the reflected light beam Lb2 made of s-polarized light by the polarization plane 34S and makes it incident on the multi lens 57. The multi lens 57 condenses the light beam Lb 2 and irradiates the photodetector 59 through the pinhole plate 58.

  Here, as shown in FIG. 10, the pinhole plate 58 is disposed so that the focal point of the reflected light beam Lb2 collected by the multi-lens 57 (FIG. 9) is located in the hole 58H. The light beam Lb2 is passed as it is.

  On the other hand, as shown in FIG. 10, the pinhole plate 58 has a focal point that is reflected from the surface of the substrate 102 in the optical disc 100, the recording mark RM that exists at a position different from the target mark position, the reflective film 104, and the like. Different light (hereinafter referred to as stray light LN) is substantially blocked. As a result, the photodetector 59 hardly detects the amount of stray light LN.

  As a result, the photodetector 75 generates the detection signal SDb corresponding to the light amount of the reflected light beam Lb2 without being affected by the stray light LN, and supplies it to the signal processing unit 23 (FIG. 5). .

  In this case, the reproduction detection signal SDb accurately represents information recorded on the optical disc 100 as the recording mark RM. For this reason, the signal processing unit 23 generates reproduction information by performing predetermined demodulation processing, decoding processing, and the like on the reproduction detection signal SDb, and supplies the reproduction information to the control unit 21.

  Incidentally, the non-polarizing beam splitter 38 reflects about 50% of the light beam passing therethrough and transmits the remaining about 50%, so that it transmits about 50% of the servo reflected light beam Ls2 and enters the information optical system 50. It will be. The transmitted servo reflected light beam Ls2 (hereinafter referred to as unnecessary servo reflected light LsN) is incident on the polarization beam splitter 34 through the mirror 54, the relay lens 53, the quarter wavelength plate 52, and the LCP 51 sequentially. The

  At this time, the unnecessary servo reflected light LsN is p-polarized light, and the unnecessary servo reflected light LsN is transmitted by the reflection / transmission film 34S of the polarization beam splitter 34. Therefore, the unnecessary servo reflected light LsN is not guided to the photodetector 59. .

  The reflected light beam Lb2 reflected by the non-polarizing beam splitter 38 (hereinafter referred to as unnecessary return light LbN) is incident on the servo optical system 30 and is polarized through the quarter-wave plate 37 and the polarizing beam splitter 36. The light enters the beam splitter 34. At this time, since the unnecessary return light LbN is s-polarized light, the unnecessary return light LbN is reflected by the reflection / transmission film 34S of the polarization beam splitter 34 and is not guided to the photodetector 59.

  As described above, the information optical system 50 receives the blue reflected light beam Lb 2 incident on the objective lens 38 from the optical disc 100 and supplies the light reception result to the signal processing unit 23.

(4) Operation and Effect In the above configuration, the optical pickup 26 of the optical disc device 20 converts the light beam Lb0 that is the emitted light into the light beam Lb1 that is the first light and the second light by the first separation unit. An optical information recording medium on which a recording mark is formed by separating light into a certain servo light Lb2, condensing the light beam Lb1 and the servo light Ls1 through the objective lens 40, and irradiating light with a predetermined intensity or higher. The objective lens 40 is driven so that the servo light Ls1 is focused on the reflective film 104 that is irradiated on a certain optical disk 100 and reflects at least a part of the servo light Ls1 formed on the optical disk 100, and the light. By changing the convergence state of the beam Lb1, the servo light Ls1 is focused in the depth direction in which the objective lens 40 approaches and separates from the optical disc 100. The focal point Fb of the light beam Lb1 is separated from the servo light focal point Fs, which is a point, by an arbitrary distance (depth d1 of the focal point Fb), and the focal point Fb is set to the target depth at the target mark position where the light beam Lb1 is to be irradiated. I tried to match.

  As a result, the optical pickup 26 can position the focal point Fb of the light beam Lb1 at the target mark position with reference to the reflective film 104. The optical pickup 26 forms the recording mark RM at the target mark position of the optical disc 100, thereby recording the recording layer of the optical disc 100. 101 can record information. Here, in the method of forming a recording mark RM made of a hologram by irradiating two light beams from both sides of the conventional optical disc 100, the recording mark RM is formed only at a position where the two light beams match. Therefore, it is difficult to stably form the recording mark RM. On the other hand, the optical pickup 26 only needs to irradiate one light beam Lb1 in accordance with the target mark position of the optical disc 100, so that the recording mark RM can be formed stably and the configuration of the optical pickup 26 can be simplified. can do.

  Further, in the optical pickup 26, the light beam Lb1 and the servo light beam Ls1 are merged by the light guide unit and guided to the objective lens 40, and the light beam Lb1 follows the reflected light beam Lb2 obtained by reflecting the light beam Lb1 by the optical disc 100. Returning to the first optical path (mirror 54, relay lens 53, quarter wavelength plate 52, LCP 51, and polarization beam splitter 34), servo reflected light Ls2 formed by reflecting the servo light beam Ls1 by the reflective film 104 is servo-reflected. It returns to the 2nd optical path (1/4 wavelength plate 37, polarization beam splitter 36, and polarization beam splitter 34) which light Ls2 followed, and it reflects from the 1st optical path and the 2nd optical path by the 1st and 2nd separation part. A photo detector that separates the light beam Lb2 or the servo reflected light beam Ls2 and receives the reflected light beam Lb2. The detector 59 or the servo reflected light beam Ls2 is guided to the photodetector 43 that receives the light.

  As a result, the optical pickup 26 can cause the light beam Lb1 and the reflected light beam Lb2 to follow the same first optical path. Therefore, the change in the convergence state generated in the light beam Lb1 can be canceled by the return optical path, and the photodetector It is not necessary to reflect the change in the convergence state in the reflected light beam Lb2 received at 59. For this reason, the optical pickup 26 does not need to be provided with an optical component for correcting the change in the convergence state, and the configuration can be simplified.

  Further, the optical pickup 26 uses a non-polarizing beam splitter 38 that transmits and reflects the light beam Lb1 and the servo light beam Ls1 at a predetermined ratio as a light guide unit, and the first light separation unit and the second light separation unit are The polarization beam splitters 34 and 36 for separating the light beam using the difference in polarization direction are used.

  As a result, the optical pickup 26 can irradiate the optical disk 100 with both the light beam Lb1 and the servo light beam Ls1 through the same objective lens 40, and utilizes the difference in polarization direction to cause the light beam Lb1 and the reflected light beam Lb2, In addition, the servo light beam Ls1 and the servo reflected light beam Ls2 can be separated and guided to the photodetectors 59 and 43, and the servo optical system 30 and the information optical system 50 can be configured with a small number of optical components.

  The polarization beam splitter 34 separates the light beam Lb0 so that the ratio of the light beam Lb1 is higher than that of the servo light beam Ls1, so that the light beam Lb1 has a predetermined intensity or more at which the recording mark RM is formed. While the recording mark RM is formed on the optical disc 100, the recording mark RM can be prevented from being formed by suppressing the servo light beam Ls below a predetermined intensity at which the recording mark RM is not formed.

  In addition, the optical disk 100 is irradiated with a predetermined initialization light Lp1 on an uncured resin 101A, which is a photoreactive resin containing an organometallic compound, and the uncured resin 101A is cured by a photoreaction to record information. Sometimes, the light beam Lb1w, which is a predetermined recording light, is condensed, whereby the temperature in the vicinity of the focal point Fb of the light beam Lb1 rises and the organometallic compound is altered to form a recording mark RM. The recording layer 101 that reproduces the information based on the reflected light beam Lb2 in response to the irradiation with the reading light beam Lb1r and the recording light beam Lb1w in the recording layer 101 are irradiated to adjust the position to an arbitrary position. A reflective film 104 that is a reflective layer that reflects at least a part of the servo light beam Lb1 having the same wavelength as the recording light beam Lb1w. It was so.

  As a result, the optical disc 100 can form the recording mark RM by a simple process of simply irradiating the recording layer 101 with the recording light beam Lb1w on the optical disc device 20, thereby simplifying the configuration of the optical disc device 20. be able to.

  According to the above configuration, the optical disc apparatus 20 separates the light beam Lb0 into the light beam Lb1 and the servo light beam Ls1, and irradiates the light beam Lb1 to form the recording mark RM, thereby forming the light beam formed on the optical disc 100. The objective lens 40 is driven so that the servo light beam Ls1 is focused on the reflective film 104 that reflects at least a part of Lb0, and the convergence state of the light beam Lb1 is changed, thereby passing the objective lens 40 through the objective lens 40. Thus, by irradiating the light beam Lb1 at a position different from the servo light focus Fs of the servo light beam Ls1 in the depth direction, the recording mark RM can be formed at an arbitrary target mark position based on the reflective film 104. Thus, an optical pickup, an optical information recording apparatus, and an optical information capable of stably recording or reproducing information with a simple configuration. Recording method, an optical information reproducing apparatus and an optical information reproducing method and an optical information recording medium capable of performing recording or reproduction of stably information can be realized.

(5) Other Embodiments In the above-described embodiment, the case where the optical disk device 20 has the optical pickup 26 having the configuration shown in FIG. 6 has been described. However, the present invention is not limited to this. For example, an optical pickup 29 configured as shown in FIG. 11 may be provided.

  In this optical pickup 29, a quarter wavelength plate 39 is provided in front of the objective lens 40 (that is, between the non-polarizing beam splitter 38 and the objective lens 40) instead of the quarter wavelength plates 37 and 52. As a result, the number of wave plates ¼ can be reduced and the configuration of the optical pickup 29 can be simplified.

  Further, in the optical pickup 29, since each optical component is arranged so that the optical path of the information optical system 50 having a large number of optical components is longer than the optical path of the servo optical system 30, the optical path length of the servo optical system 30 is increased. The entire length of the optical pickup 29 can be reduced by shortening the overall optical path length and reducing the overall optical path length.

  In the above-described embodiment, the case where the present invention is applied to the optical disc apparatus 20 in which the recording mark RM is formed in the recording layer 101 due to the alteration of the organometallic compound has been described. Not limited to this, a hologram is formed in advance on the entire recording layer 101 whose refractive index changes due to light irradiation, and the recording mark RM is formed by destroying the hologram by irradiation with the light beam Lb1. The present invention may be applied to such an optical disc apparatus.

  Furthermore, in the above-described embodiment, the case where the reflective film 104 is made of a reflective film that reflects almost all of the blue laser light has been described. However, the present invention is not limited to this, and the blue laser light is distributed at a certain ratio. It may be formed as a reflection / transmission film that reflects and transmits (for example, 1: 1). Thereby, even if the optical disk 100 is a case where the board | substrate 102 is damaged, for example, it becomes possible to read information by irradiating the light beam Lb1 from the board | substrate 103 side.

  Further, in the above-described embodiment, the case where the reflective film 104 is provided between the substrate 103 on the opposite side of the objective lens 40 and the recording layer 101 has been described, but the present invention is not limited to this, For example, as shown in FIG. 12, the reflective film 104x may be provided between the substrate 102 on the objective lens 40 side and the recording layer 101.

  In this case, the reflection film 104 is formed as a reflection / transmission film 104x that reflects, for example, 50% of the light having a wavelength to be used (blue laser light), thereby reflecting the servo light beam Ls1 to generate the servo reflection light beam Ls2. Can be generated.

  Also, as shown in FIG. 13, two recording layers 101A and 101B may be provided on the optical disc 100, and a reflective film 104y may be formed on the boundary surface between the recording layers 101A and 101B. At this time, the reflection film 104y is formed as a total reflection film, for example, and the optical disc device 20 has two objective lenses 40x and 40y, and two light beams Lb1 are emitted from the two objective lenses 40x and 40y to the recording layer 101A. And two target mark positions in 101B may be irradiated.

  At this time, the optical disc apparatus 20 can use only one servo light beam Ls1 and irradiate the same track of the different recording layers 101a and 101b with the two light beams Lb1 by simultaneously controlling the objective lenses 40x and 40y. . In the figure, the reflected light beam Lb2 is omitted for convenience.

  The optical disk device 20 may use two servo light beams Ls2 (not shown) and irradiate two light beams Lb1 on different tracks of different recording layers 101a and 101b.

  As a result, the optical disc apparatus 20 can perform two recording processes or reproduction processes in parallel by the two light beams Lb via the two objective lenses 40x and 40y. Speed can be improved.

  Further, in the optical disc 100, the reflective film 104y is used as a transmissive reflective film 104z (not shown), so that, for example, the light beam Lb1 is irradiated only from the substrate 102 side to form the recording marks RM on the recording layers 101A and 101B. Can do.

  In this optical disc 100, the reflective film 104y is provided at substantially the center of the optical disc 100, and both sides thereof have a symmetrical structure. Therefore, the physical characteristics such as the thermal contraction rate on both sides of the reflective film 104y are centered. They can be matched, and the occurrence of warpage can be suppressed.

  Further, in the above-described embodiment, the case where the recording mark is formed by the alteration of the organometallic compound contained in the recording layer 101 has been described. However, the present invention is not limited to this. The recording mark may be formed by raising the temperature to a temperature equal to or higher than the glass transition point of 101 to form a cavity.

  Further, in the above-described embodiment, the case where the recording mark RM is formed on the disc-shaped optical disc 100 has been described. However, the present invention is not limited to this, and for example, optical information recording in a cube shape (cuboid). The recording mark RM may be recorded on the medium.

  Further, in the above-described embodiment, the optical pickup 26 as the optical pickup is constituted by the polarization beam splitter 34 as the first light separation unit, the objective lens 40 as the objective lens, and the relay lens 53 as the focus moving unit. Although the case where it comprises is described, this invention is not restricted to this, The optical pick-up of this invention is comprised by the 1st light separation part which consists of other various structures, an objective lens, and a focus moving part. You may do it.

  Furthermore, in the above-described embodiment, the polarizing beam splitter 34 as the first light separation unit, the objective lens 40 as the objective lens, the biaxial actuator 40A as the objective lens driving unit, and the relay as the focus moving unit. Although the case where the optical disk device 20 as an optical information recording device is configured by the lens 53 has been described, the present invention is not limited to this, and the first light separation unit having various other configurations, the objective lens, The optical information recording apparatus of the present invention may be configured by the objective lens driving unit and the focus moving unit.

  Furthermore, in the above-described embodiment, the polarizing beam splitter 34 as the first light separation unit, the objective lens 40 as the objective lens, the biaxial actuator 40A as the objective lens driving unit, and the relay as the focus moving unit. Although the case where the optical disc apparatus 20 as the optical information reproducing apparatus is configured by the lens 53 and the photodetector 59 as the light receiving unit has been described, the present invention is not limited to this, and the first light having various other configurations. You may make it comprise the optical information reproducing | regenerating apparatus of this invention with a isolation | separation part, an objective lens, an objective lens drive part, a focus moving part, and a light-receiving part.

  Further, in the above-described embodiment, the case where the optical disc 100 as the optical information recording medium is configured by the recording layer 101 as the recording layer and the reflective film 104 as the reflective layer has been described. However, the present invention is not limited to this, and the optical information recording medium of the present invention may be configured by a recording layer having various other configurations and a reflective layer.

  The present invention can be used in an optical disc apparatus that records or reproduces a large amount of information such as video content and audio content on a recording medium such as an optical disc.

1 is a schematic diagram showing an external configuration of an optical disc. It is a basic diagram which shows the internal structure of an optical disk. It is an approximate line figure used for explanation of formation of a recording mark. It is an approximate line figure used for explanation of initialization of an optical disc. It is a basic diagram which shows the structure of an optical disk device. It is a basic diagram which shows the structure of an optical pick-up. It is a basic diagram with which it uses for description of the optical path of a servo light beam. It is a basic diagram which shows the structure of the detection area | region in a photodetector. It is a basic diagram with which it uses for description of the optical path of a light beam. It is a basic diagram with which it uses for description of the selection of the light beam by a pinhole. It is a basic diagram which shows the structure of the optical pick-up by other embodiment. It is a basic diagram which shows the structure (1) of the optical disk by other embodiment. It is a basic diagram which shows the structure (2) of the optical disk by other embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 20 ... Optical disk apparatus, 21 ... Control part, 26 ... Optical pick-up, 30 ... Servo optical system, 31 ... Laser diode, 34, 36 ... Polarizing beam splitter, 37, 52 ... 1/4 wavelength plate , 38... Non-polarizing beam splitter, 40... Objective lens, 43 and 59... Photo detector, 50. , Ls2: servo reflected light beam, 100: optical disk, 101: recording layer, 102, 103: substrate, 104: reflective film.

Claims (19)

In an optical pickup that emits emitted light emitted from a light source to an optical information recording medium on which a recording mark is formed by irradiation with light having a predetermined intensity or more,
A first light separation unit for separating the emitted light into first light and second light;
An objective lens that collects the first light and the second light and irradiates the optical information recording medium;
An objective lens driving unit that drives the objective lens to focus the second light on a reflective layer that is formed on the optical information recording medium and reflects at least a part of the second light;
By changing the convergence state of the first light, the focus of the first light is changed from the focus of the second light in the depth direction in which the objective lens approaches and separates from the optical information recording medium. An optical pickup comprising: a focal point moving unit that separates the first light beam by an arbitrary distance and adjusts the focal point of the first light to a target depth to be irradiated with the first light. The first light and the second light are combined and guided to the objective lens, and the first light is reflected by the first information light reflected by the optical information recording medium. A light guide unit that returns the second reflected light, which is returned to the first optical path followed by the second light and is reflected by the reflective layer, to the second optical path traced by the second light;
A first light receiving portion for receiving the first reflected light;
A second light receiving portion for receiving the second reflected light;
Either the first reflected light or the second reflected light is separated from the first optical path or the second optical path, and guided to the corresponding first light receiving section or the second light receiving section. A second light separation unit,
The first light separation unit includes:
Separating the other of the first reflected light or the second reflected light from the first optical path or the second optical path and guiding it to the corresponding first light receiving part or the second light receiving part. The optical pickup according to claim 1, wherein The light guide is
A non-polarizing beam splitter that transmits and reflects the first light and the second light at a predetermined ratio;
The first light separation unit and the second light separation unit are
The optical pickup according to claim 2, comprising a polarization beam splitter that separates the light using a difference in polarization direction. The first light separation unit includes:
By separating the emitted light so that the ratio of the first light is higher than that of the second light, the first light is set to be higher than the intensity, while the second light is set to be less than the intensity. The optical pickup according to claim 1, wherein: The focal point moving part is
The optical pickup according to claim 4, comprising a relay lens in which a fixed lens and a movable lens moving in the optical axis direction of the first light are combined. A quarter-wave plate is provided between the objective lens and the light guide unit and converts the first light and the second light, which are linearly polarized light, into circularly polarized light. 3. The optical pickup according to 3. The first light and the second light which are provided between the first light separation unit and the light guide unit and between the second light separation unit and the light guide unit, respectively, and are linearly polarized light. The optical pickup according to claim 3, further comprising two quarter-wave plates for converting light into circularly polarized light. The optical pickup according to claim 2, further comprising a pinhole plate for removing stray light reflected at a position different from the focal point of the first light, in a stage preceding the first light receiving unit. In an optical information recording apparatus for irradiating light emitted from a light source to an optical information recording medium on which a recording mark is formed by irradiation with light having a predetermined intensity or more,
A first light separation unit that separates the emitted light into first light having the above-described intensity and second light;
An objective lens that collects the first light and the second light and irradiates the optical information recording medium;
An objective lens driving unit that drives the objective lens to focus the second light on a reflective layer that is formed on the optical information recording medium and reflects at least a part of the second light;
By changing the convergence state of the first light, the focus of the first light is changed from the focus of the second light in the depth direction in which the objective lens approaches and separates from the optical information recording medium. An optical information recording apparatus comprising: a focal point moving unit that separates the first light beam by an arbitrary distance and adjusts the focal point of the first light to a target depth to be irradiated with the first light. In an optical information reproducing apparatus for irradiating light emitted from a light source to an optical information recording medium on which a recording mark is formed by being irradiated with light having a predetermined intensity or more,
A first light separation unit for separating the emitted light into first light and second light;
An objective lens that collects the first light and the second light and irradiates the optical information recording medium;
An objective lens driving unit that drives the objective lens to focus the second light on a reflective layer that is formed on the optical information recording medium and reflects at least a part of the second light;
By changing the convergence state of the first light, the focus of the first light is changed from the focus of the second light in the depth direction in which the objective lens approaches and separates from the optical information recording medium. And a focal point moving unit that adjusts the focal point of the first light to a target depth to be irradiated with the first light;
An optical information reproducing apparatus comprising: a light receiving portion that receives a reflected light beam formed by reflecting the first light on the recording mark. In an optical information recording method of irradiating emitted light emitted from a light source to an optical information recording medium on which a recording mark is formed by irradiation with light having a predetermined intensity or more,
A first light separation step of separating the emitted light into a first light having a strength equal to or higher than the intensity and a second light;
An irradiation step of condensing the first light and the second light and irradiating the optical information recording medium;
An objective lens driving step for driving the objective lens to focus the second light on a reflective layer formed on the optical information recording medium and reflecting at least a part of the second light;
By changing the convergence state of the first light, the focus of the first light is changed from the focus of the second light in the depth direction in which the objective lens approaches and separates from the optical information recording medium. And a focal point moving step for adjusting the focal point of the first light to a target depth to be irradiated with the first light. In an optical information reproducing method of irradiating an optical information recording medium on which a recording mark is formed by irradiating light having a predetermined intensity or more with an emitted light emitted from a light source,
A first light separation step for separating the emitted light into first light and second light;
An irradiation step of condensing the first light and the second light and irradiating the optical information recording medium;
An objective lens driving step for driving the objective lens to focus the second light on a reflective layer formed on the optical information recording medium and reflecting at least a part of the second light;
By changing the convergence state of the first light, the focus of the first light is changed from the focus of the second light in the depth direction in which the objective lens approaches and separates from the optical information recording medium. And a focal point moving step for adjusting the focal point of the first light to a target depth to be irradiated with the first light;
And a light receiving step of receiving a reflected light beam formed by reflecting the first light on the recording mark. A resin containing an organometallic compound and having photoreactivity is cured by a photoreaction caused by irradiation of predetermined initialization light, and the recording is performed by collecting predetermined recording light during information recording. The temperature in the vicinity of the focal point of the light rises, the organometallic compound is altered to form a recording mark, and the information is reproduced based on the return light in response to irradiation with a predetermined reading light when reproducing the information. A recording layer;
An optical information comprising: a reflective layer that reflects at least a part of servo light having the same wavelength as that of the recording light irradiated to adjust the position of the recording light in the recording layer to an arbitrary position. recoding media. The recording layer is
The optical information recording medium according to claim 13, wherein when the initialization light is irradiated, the optical metal is cured by a photoreaction and the organometallic compound is photochemically changed by the initialization light. The optical information recording medium according to claim 13, further comprising two protective layers sandwiching the recording layer and the reflective layer. The reflective layer is
The optical information recording medium according to claim 13, wherein all of the recording light is reflected. The reflective layer is
14. The optical information recording medium according to claim 13, wherein irregularities representing positions in a direction parallel to the reflective layer in the optical information recording medium are formed. The recording layer is
The optical information recording medium according to claim 13, comprising two layers sandwiching the reflective layer. The recording layer is
The optical information recording medium according to claim 13, wherein the recording mark is formed by forming a cavity when recording the information.

Images