JP4172358B2 - Optical pickup device, optical disk device, focus error detection method, and tracking error detection method - Google Patents

Description

  The present invention relates to an integrated optical member used for recording and reproduction of an optical disc, an optical pickup device using the integrated optical member, an optical disc device using the optical pickup device, a focus error detection method for the optical pickup device, and a tracking error It relates to a detection method.

  Conventional optical pickups have been devised to separate the light-emitting light source side and the detection optical system by using many types of beam splitters. However, as a result of increasing market demand for downsizing the optical pickup, an attempt has been made to provide an optical unit in which the light source and the detection optical system are accommodated in the same package.

  In order to realize this optical unit, an optical member formed with a diffraction grating was used. As for a specific example of this optical member, a detailed technical disclosure is made in (Patent Document 1). Thus, by realizing the optical member, the optical pickup has been greatly reduced in size, and a small-sized optical disk device equipped with a small-sized optical pickup has spread to the market.

  However, the progress of miniaturization and the widespread use of optical disk devices have included the following new problems. For example, as a matter of course, the light emitting light source, the detection element, and the optical member come closer to each other by downsizing. In addition, the use of light for a long time and the expansion of recording applications increase the light output of the light-emitting light source and increase the use temperature. Furthermore, as seen in the widespread use of notebook PCs, the environmental temperature that is housed and used in smaller housings is further expanding.

  As described above, when the operating temperature range is expanded, the influence of the thermal expansion coefficient of each component constituting the optical unit is brought to the surface. For example, if the size and position of the optical member on which the diffraction grating is formed are affected, the cause of error and offset in servo control increases.

An integrated optical member capable of realizing a signal detection operation without being affected by a detection optical system due to such a change in operating temperature, an optical pickup device using the integrated optical member, and the optical pickup device The optical disk device used is described in (Patent Document 2).
Japanese Patent Laid-Open No. 10-154344 JP 2002-175634 A

  In recent years, optical disc apparatuses have been diversified, and it is possible to record / reproduce with a single apparatus for CDs (Compact Disks) and DVDs (Digital Versatile Disks). The wavelength of the laser beam used for CD recording / reproduction is different from that for DVD recording / reproduction, and in order to perform both recording / reproduction, two types of laser light sources having different wavelengths are used. In such an apparatus, it is necessary to accurately perform a signal detection operation for recording / reproducing a CD and a signal detection operation for recording / reproducing a DVD. It is necessary to be able to do without being affected by fluctuations.

The present invention has been made to solve the above-described problems. In an apparatus for recording / reproducing data on a CD and a DVD, the detection optical system is not affected by fluctuations in the operating temperature, and the influence of crosstalk. It is an object of the present invention to provide a focus error detection method and a tracking error detection method together with an optical pickup device capable of realizing a detection operation of a signal that is not easily received, and an optical disk device using the optical pickup device.

The present invention has been made in order to solve the above-described problem, and has a dividing surface for extracting a light beam necessary for tracking control and focus control from reflected light emitted from a light source for CD and reflected by CD. Diffracted by a hologram for CD having, a DVD hologram having a split surface for extracting a light beam necessary for tracking control and focus control from reflected light emitted from a light source for DVD and reflected by DVD, and DVD hologram A light receiving means for receiving the converted light and converting it into an electrical signal, the light receiving means for extracting a light beam necessary for focus control in a division line parallel to the radial direction of the DVD and in the tangential direction of the DVD. It is formed by five divided regions that receive the diffracted light of the region divided by the parallel dividing lines, and the detection signal of the light receiving means. Provided is an optical pickup device characterized in that a focus error signal (FE) is calculated by a relational expression of FE = (IA1 + IA2) − (IB1 + IB2 + IB3) when the codes are IA1, IA2, IB1, IB2, and IB3, respectively. Is.

  According to the present invention, the detection optical system is not affected by fluctuations in the operating temperature, a signal detection operation that is not easily affected by crosstalk can be realized, and the emission of laser light emitted from the light source can be realized. Even if the pattern is displaced, the signal detection operation can be performed accurately.

  According to the optical pickup device of the present invention, the detection optical system is not affected by fluctuations in the operating temperature, a signal detection operation that is not easily affected by crosstalk can be realized, and the signal is emitted from the light source. Even if a deviation occurs in the laser light emission pattern, the signal detection operation can be performed accurately.

  In addition, according to the optical disk device of the present invention, the detection optical system is not affected by fluctuations in the operating temperature, a signal detection operation that is not easily affected by crosstalk can be realized, and the signal is emitted from the light source. Even if a deviation occurs in the emission pattern of the laser beam, the signal detection operation can be performed accurately, and information can be recorded and reproduced on the optical disk.

  In addition, according to the focus error detection method of the optical pickup device of the present invention, the detection signal drift and offset caused by the change in use temperature are canceled, and the detection optical system is not affected by the change in use temperature. A focus error detection method for the pickup device can be realized.

  Further, according to the tracking error detection method of the optical pickup device of the present invention, the detection optical system is not affected by the fluctuation of the use temperature because the drift or offset of the detection signal caused by the change of the use temperature is canceled. A tracking error detection method for a pickup device can be provided, and a tracking error detection method for an optical pickup device that is not affected even if a deviation occurs in the emission pattern of a laser beam emitted from a light source. Can do.

According to a first aspect of the present invention, there is provided a CD hologram having a split surface for extracting a light beam necessary for tracking control and focus control from reflected light emitted from a CD light source and reflected by a CD; Receives a DVD hologram having a split surface for extracting a light beam necessary for tracking control and focus control from reflected light emitted from a DVD light source and reflected by the DVD, and light diffracted by the DVD hologram. Light receiving means for converting into an electrical signal, and the light receiving means is divided by a dividing line parallel to the radial direction of the DVD and a dividing line parallel to the tangential direction of the DVD for extracting a light beam necessary for focus control. Formed by five divided regions for receiving the diffracted light of the formed region, and the detection signals of the light receiving means are respectively IA1 and IA In this optical pickup device, when 2, IB1, IB2, and IB3 are set, a focus error signal (FE) is calculated by a relational expression of FE = (IA1 + IA2) − (IB1 + IB2 + IB3) .

According to a second aspect of the present invention, there is provided a CD hologram having a split surface for extracting a light beam required for tracking control and focus control from reflected light emitted from a CD light source and reflected by a CD; Receives a DVD hologram having a split surface for extracting a light beam necessary for tracking control and focus control from reflected light emitted from a DVD light source and reflected by the DVD, and light diffracted by the DVD hologram. A light receiving means for converting into an electrical signal, and the light receiving means is divided by a dividing line parallel to the radial direction of the DVD and a dividing line parallel to the tangential direction of the DVD for extracting a light beam necessary for tracking control. Tracking control that takes into account the deviation of the diffracted light in the selected area and the emission pattern of the laser light emitted from the DVD light source It is formed by eight regions that receive the diffracted light of the region divided by the dividing line parallel to the tangential direction of the DVD for extracting the necessary light flux, and the detection signals of the light receiving means are respectively IC, IE, IG , ID, IF, IH, Iα, Iβ, the tracking error signal (TE) is set to TE = (IC + Iα) − (ID + Iβ) −k {(IE + IG) − (IF + IH)} (where k is an operation setting) The optical pickup device is calculated by a relational expression (constant determined accordingly) .

According to a third aspect of the present invention, in the optical pickup device according to the first or second aspect, the CD hologram includes a central region divided into three by two dividing lines parallel to the radial direction of the CD. It is divided into two arcuate regions separated in the tangential direction, and the central region is further divided into substantially D-shaped regions further divided into two by dividing lines parallel to the tangential direction of the CD. Thus, the entire area of the CD hologram is divided into two arched areas and two substantially D-shaped areas and divided into approximately four equal areas .

According to a fourth aspect of the present invention, in the optical pickup device according to the third aspect, in each of the two arcuate regions, separation gratings that diffract in the same direction as the substantially D-shaped region are formed. Features.

According to a fifth aspect of the present invention, in the optical pickup device according to any one of the first to fourth aspects, the hologram for CD guides the luminous flux of the light emitting element of the light source for CD to the CD and from the CD. It is formed on any one of a plurality of optical surfaces formed inside an integrated optical member having a function of separating a necessary light beam from reflected light .

According to a sixth aspect of the present invention, in the optical pickup device according to any one of the first to fifth aspects, the light receiving means for receiving the light diffracted by the CD hologram and converting it into an electrical signal is provided for the CD. Diffracted light of the first arcuate region with respect to the first arcuate region, the second arcuate region, and the first substantially D-shaped region and the second substantially D-shaped region obtained by separating the hologram in the tangential direction , Two light receiving means for receiving the diffracted light of the second arcuate region, three light receiving means for receiving the diffracted light of the first substantially D-shaped region, And three light receiving means for receiving diffracted light in the substantially D-shaped region .

According to a seventh aspect of the present invention, in the optical pickup device according to the sixth aspect, the light receiving means for receiving the light diffracted by the CD hologram and converting it into an electric signal, The detection signals of the two light receiving means that receive the diffracted light are IA4 and IB4, respectively, and the detection signals of the two light receiving means arranged in the reverse order of receiving the diffracted light of the second arcuate region are IA5 and IB5, respectively. Then, the focus error signal (FE) is calculated by a relational expression of FE = (IA4 + IA5) − (IB4 + IB5) .

According to an eighth aspect of the present invention, in the optical pickup device according to the sixth aspect, the light receiving means for receiving the light diffracted by the hologram for CD and converting it into an electric signal, wherein the first substantially D-shaped The detection signals of the three light receiving means for receiving the diffracted light in the region are respectively IC, IE, and IG, and the detection signals of the three light receiving means for receiving the diffracted light in the second substantially D-shaped region are respectively ID , IF, IH, the tracking error signal (TE) is calculated by the relational expression TE = IC-ID-k {(IE + IG)-(IF + IH)} (where k is a constant determined according to the operation setting). characterized in that it.

According to a ninth aspect of the present invention, there is provided an optical disc apparatus using the optical pickup device according to any one of the first to ninth aspects.

The invention according to claim 10 of the present invention is required for tracking control and focus control from the reflected light emitted from the light source for CD and reflected by the CD for recording and reproducing information by irradiating the CD with laser light. Tracking control among a hologram for CD having a split surface for extracting a luminous flux and a reflected light emitted from a light source for DVD for recording and reproducing information by irradiating a DVD with laser light and reflected by the DVD And a DVD hologram having a dividing surface for extracting a light beam necessary for focus control, and the DVD hologram includes a dividing line parallel to the radial direction of the DVD for extracting the light beam necessary for focus control. A region divided by a dividing line parallel to the tangential direction of the DVD is formed, and the light diffracted by the DVD hologram is received. The light receiving means for converting into an electric signal is a diffracted light of a region divided by a dividing line parallel to the radial direction of the DVD and a dividing line parallel to the tangential direction of the DVD for extracting a light beam necessary for focus control. A focus error detection method for an optical pickup device formed by five light receiving means for receiving a light beam, and a dividing line parallel to the radial direction of the DVD and a DVD tanger for extracting a light beam necessary for focus control. When the detection signals of the five light receiving means for receiving the diffracted light of the region divided by the dividing line parallel to the local direction are IA1, IA2, IB1, IB2, and IB3, the focus error signal (FE) is FE = (IA1 + IA2) − (IB1 + IB2 + IB3) This is a focus error detection method characterized in that it is calculated by the relational expression .

The invention according to claim 11 of the present invention is necessary for tracking control and focus control from the reflected light emitted from the light source for CD for recording and reproducing information by irradiating the CD with laser light and reflected by the CD. Tracking control among a hologram for CD having a split surface for extracting a luminous flux and a reflected light emitted from a light source for DVD for recording and reproducing information by irradiating a DVD with laser light and reflected by the DVD And a DVD hologram having a dividing surface for extracting a light beam necessary for focus control, and the DVD hologram has a dividing line parallel to the radial direction of the DVD for extracting the light beam necessary for tracking control. And the area divided by the dividing line parallel to the tangential direction of the DVD and the emission pattern of the laser light emitted from the DVD light source In order to extract the light flux necessary for tracking control in consideration of this, an area divided by a dividing line parallel to the tangential direction of the DVD is formed, and the light diffracted by the DVD hologram is received as an electric signal. The light receiving means for converting into a diffracted light of a region divided by a dividing line parallel to the radial direction of the DVD and a dividing line parallel to the tangential direction of the DVD for extracting a light beam necessary for tracking control, Receiving the diffracted light of the region divided by the dividing line parallel to the tangential direction of the DVD for extracting the light flux necessary for tracking control considering the deviation of the emission pattern of the laser light emitted from the light source 8 A tracking error detection method for an optical pickup device formed by a single light receiving means, which extracts a light beam necessary for tracking control. Therefore, the deviation of the diffraction pattern of the region divided by the dividing line parallel to the radial direction of the DVD and the dividing line parallel to the tangential direction of the DVD and the emission pattern of the laser light emitted from the DVD light source are considered. The detection signals of the eight light receiving means for receiving the diffracted light of the region divided by the dividing line parallel to the tangential direction of the DVD for extracting the light flux necessary for the tracking control are respectively IC, IE, IG, ID , IF, IH, Iα, Iβ, the tracking error signal (TE) is set to TE = (IC + Iα) − (ID + Iβ) −k {(IE + IG) − (IF + IH)} (where k corresponds to the operation setting) The tracking error detection method is characterized in that it is calculated by a relational expression of (constant constant).

  With the above configuration of the present invention, the detection optical system is not affected by fluctuations in the operating temperature, a signal detection operation that is not easily affected by crosstalk can be realized, and laser light emitted from the light source can be realized. Even if a deviation occurs in the emission pattern, it is possible to realize an optical pickup device that can accurately detect a signal.

  According to the present invention, it is possible to provide a tracking error detection method for an optical pickup device in which drift or offset of a detection signal caused by a change in use temperature is canceled and the detection optical system is not affected by the change in use temperature. In addition, it is possible to provide a tracking error detection method for an optical pickup device that is not affected even when a deviation occurs in the emission pattern of laser light emitted from a light source.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration of an optical pickup device according to an embodiment of the present invention.

  This embodiment is based on the premise that it can be used for both CD and DVD. Laser light with a wavelength of 780 nm is used for CD and laser light with a wavelength of 660 nm is used for DVD.

  The laser light emitted from the DVD laser module 1 is reflected by the reflecting mirror 2 to change the traveling direction, and is converted from divergent light to parallel light by the collimator lens 3. The parallel light is transmitted through the beam splitter 4 and its traveling direction is changed by the rising prism 5. The beam splitter 4 is formed with a multilayer film for transmitting the DVD laser light and reflecting the CD laser light. The rising prism 5 is formed with a multilayer film for reflecting both the DVD laser light and the CD laser light with high reflectivity. The light reflected by the rising prism 5 passes through the DVD hologram 6, is condensed by the objective lens 7, and is applied to the optical disk 8.

  The light reflected by the optical disk 8 passes through the objective lens 7, the DVD hologram 6, and the rising prism 5, is reflected by the beam splitter 4, is collected by the lens 9, and then enters the integrated optical member 20. . Although details of the structure of the integrated optical member 20 will be described later, the light enters the light receiver 60 from the integrated optical member 20.

  On the other hand, the laser light emitted from the light source 10 for CD is transmitted through the integrated optical member 20, converted into parallel light by the lens 9, and reflected by the beam splitter 4. Thereafter, the light is reflected by the rising prism 5 to change the traveling direction, passes through the DVD hologram 6, is condensed by the objective lens 7, and is applied to the optical disk 8.

  The light reflected by the optical disk 8 passes through the objective lens 7, the DVD hologram 6, and the rising prism 5, is reflected by the beam splitter 4, is collected by the lens 9, and then enters the integrated optical member 20. . Although details of the structure of the integrated optical member 20 will be described later, the light enters the light receiver 60 from the integrated optical member 20.

  FIG. 2 shows the configuration of the integrated optical member 20.

  FIG. 2 shows each light guide member constituting the integrated optical member 20 in an exploded state, and the integrated optical member 20 is constituted by first to fifth light guide members. As the material of each light guide member, a highly transmissive resin material or optical glass is used. In particular, the optical glass of SFL-1.6 and BK-7 has a high refractive index, so that the design margin of the diffraction grating and the film can be increased, and the wavelength shift at the time of transmission hardly occurs. Among them, BK-7-1.5 is convenient because it is easily available and has excellent workability.

Next, each light guide member will be described. The first light guide member 21 is formed in a parallel plate shape. A first diffraction grating 22 is formed on the surface where the first light guide member 21 faces the exit of the laser light source 10. This is because main and sub beams (hereinafter collectively referred to as three beams) used for tracking control are generated using the diffracted 0th order light and ± 1st order light.

Further, a light absorption film 23 is formed on the entire surface except the region through which the light beam passes on the emission surface of the first light guide member 21. The composition of the light absorption film 23 is formed of, for example, a multilayer film of Si, Ti, and SiO ₂ . This is because unnecessary light such as irregular reflection or stray light is not introduced into the optical path of the integrated optical member 20 and the light beam.

  The second light guide member 25 is formed in a substantially triangular prism shape having a substantially right triangle cross section. A wavelength selection film 27 is formed in a required region on the inclined surface 26 of a substantially right triangle. The wavelength selection film 27 is for separating the outward light for CD and the backward light for DVD, and has a function of transmitting the outward light for CD and reflecting the backward light for DVD. Since the laser beam for CD and the laser beam for DVD have different wavelengths, the wavelength selection film 27 can separate them.

  The third light guide member 30 is formed in a plate shape having parallel planes facing each other, the first inclined surface 31 and the second inclined surface 32 form parallel planes facing each other, and a broadband polarization separation film 33 is formed on the first inclined surface 31. Has been. The broadband polarization separation film 33 is for separating the outward light for CD and the backward light for CD, and has a function of transmitting the outward light for CD and reflecting the backward light for CD. Since the forward light for CD and the return light for CD have different polarization states, both can be separated by the broadband polarization separation film 33.

  The fourth light guide member 35 is formed in a substantially trapezoidal column shape having a substantially trapezoidal cross section. Each surface has a first inclined surface 36, a second inclined surface 37, a transmitting surface 38, and an emitting surface 39. The first slope 36 and the second slope 37 are parallel planes facing each other, and a CD hologram 40 is formed in a predetermined region of the first slope 36. Further, an APC reflection film 41 is provided on the upper surface of the CD hologram 40. The function of the CD hologram 40 will be described later.

  With respect to the fourth light guide member 35, the forward light for CD is transmitted from the second inclined surface 37 to the transmission surface 38, and the backward light for CD is reflected by the second inclined surface 37 and then passes through the CD hologram 40 to be APC reflected. After being reflected by the film 41 and again reflected by the second inclined surface 37, it is emitted from the emission surface 39. Similarly, DVD return light is also emitted from the exit surface 39.

  The fifth light guide member 45 is formed in a substantially triangular prism shape having a right triangle cross section. Each surface is a slope 46, a first surface 47, and a second surface 48. The first surface 47 and the second surface 48 intersect at a right angle and become the reference surface of the integrated optical member 20. A light absorption film 49 is formed on the slope 46.

  FIG. 3 shows optical paths of the DVD laser light and the CD laser light until they enter the light receiver 60.

  Necessary connections are made to the leads 18, and the laser element 13 emits diffused light 101 for CD from a light emitting point 19. The diffused light 101 enters the first light guide member 21. In the first light guide member 21, unnecessary disturbance light and light that has spread beyond a predetermined diffusion angle are absorbed by the light absorption film 23, and the diffused light 101 is transmitted by the first diffraction grating 22 to the three-beam CD outward light 102. Convert to

The forward light 102 for CD enters the second light guide member 25 from the first light guide member 21. The forward light 102 for CD that has traveled through the second light guide member 25 reaches the slope 26. Most of the light amount of the forward light 102 for the CD passes through the wavelength selection film 27 and enters the third light guide member 30. Further, the light beam passes through the first inclined surface 31 of the third light guide member 30 and further passes through the transmission surface 38 of the fourth light guide member 35, and the path is changed toward the optical disk 6 by the beam splitter 4 and the rising prism 5. Then, it becomes convergent light by the objective lens 7 and enters the optical disk 8.

  The return light 104 reflected from the recording layer of the optical disk 8 enters the transmission surface 38 of the fourth light guide member 35 through the objective lens 7 and the rising prism 5 in reverse order. The return light 104 for CD is reflected by the broadband polarization separation film 33 and proceeds to the CD hologram 40 of the third light guide member 35. In the CD hologram 40, the return-path reflected diffracted light 105 for CD mainly includes + 1st order diffracted light. The return-path reflected diffracted light 105 for CD is reflected again by the broadband polarization separation film 33 of the third light guide member 30 and is emitted from the emission surface 39 toward the light receiver 60.

  On the other hand, the return light 110 for DVD is reflected by the wavelength selection film 27 formed on the slope 26 of the second light guide member 25, passes through the third light guide member 30 and the fourth light guide member 35, and exits. The light is emitted from 39 toward the light receiver 60.

  FIG. 4 is an overall perspective view of the light receiver 60. An OE element 63 is accommodated in a package 61 having an incident port 62. The signal terminal of the OE element 63 is connected to the lead terminal 64 and guided to the outside of the package 61. Further, a flexible cable 65 is connected to the lead terminal 64 and used for inspection and mounting.

  Next, the DVD hologram 6 and the CD hologram 40 will be described.

  The DVD hologram 6 is provided immediately below the objective lens 7, and the DVD backward light passing through the DVD hologram 6 forms an image on the OE element 63 in the light receiver 60. The CD hologram 40 is provided in a predetermined region of the first inclined surface 36 of the fourth light guide member 35, and the CD return light passing through the CD hologram 40 forms an image on the OE element 63 in the light receiver 60. To do.

  FIG. 5 shows a division pattern of the CD hologram 40 and a pattern 201 of the OE element 63 provided in the light receiver 60. Further, the pattern of the OE element 63 viewed from the incident port 62 is shown.

  In FIG. 5, reference numeral 70 denotes a diffraction grating that functions as the CD hologram 40. The diffraction grating 70 is divided into a grating A71, a grating B72, a grating C73, and a grating D74.

  Specifically, the diffraction grating 70 is divided into three parts by two parting lines parallel to the radial (radius) direction (X axis) of the optical disc, and is divided into arcs thereof in the tangential (track tangent: Y axis) direction. One of the separated regions is a lattice A71, and the other is a lattice B72. The regions where the reflected diffracted light of the grating A71 forms an image are the light receiving means 201A5 and the light receiving means 201B5 provided at the center of the light receiving means 201. The region where the reflected diffracted light of the grating B72 forms an image is the light receiving means 201A4 and the light receiving means 201B4 provided at the lower center of the light receiving means 201. That is, these become main beams for focus detection.

  Further, the remaining divided area, that is, the central divided area, is further divided into two by dividing lines parallel to the tangential (track tangent: Y axis) direction of the optical disc, which are a lattice C73 and a lattice D74, respectively. That is, the area | region of the grating | lattice C73 and the grating | lattice D74 is formed in a substantially D shape.

  Further, a separation grating A75 corresponding to the grating C73 is provided in the area of the grating A71, and similarly, a separation grating B76 corresponding to the grating C73 is provided in the area of the grating B72. Further, a separation grating C77 corresponding to the grating D74 is provided in the area of the grating A71, and a separation grating D78 corresponding to the grating D74 is provided in the area of the grating B72.

The grating C73, the separation grating A75, and the separation grating B76 are diffracted in the same direction, that is, the position of the same OE element, and the grating D74, the separation grating C77, and the separation grating D78 are in the same direction, that is, the same OE element. A separation grating D78 is formed from each separation grating A75 so as to be diffracted to the position. Each of the separation grating A75 to the separation grating D78 has the same area and diffracted optical power conditions.

  As described above, since the grating C73, the separation grating A75, and the separation grating B76 are diffracted in the same direction, the diffracted light from the main beam grating C73 enters the light receiving means 201C and is separated from the main beam separation grating A75. Diffracted light from the grating B76 also enters the light receiving means 201C. Similarly, the diffracted light of the sub beam of ± 1st order light is incident on the light receiving means 201E and 201G, respectively.

  Further, since the grating D74, the separation grating C77, and the separation grating D78 are diffracted in the same direction, the diffracted light from the main beam grating D74 is incident on the light receiving means 201D, and the main beam separation grating C77 and the separation grating D78 The diffracted light by is also incident on the light receiving means 201D. Similarly, the diffracted light of the sub beam of ± 1st order light is incident on the light receiving means 201F and 201H, respectively. These six types of light receiving areas are detected as three beams for tracking control.

When the detected current subjected to OE conversion is represented by symbol I, IA5, IB5, IA4, IB4, etc. are obtained by the respective light receiving means. Therefore, the detection current can be logically configured as follows for focus detection. That is, as a focus error (hereinafter abbreviated as FE) detection logic,
FE = (IA4 + IA5) − (IB4 + IB5) (Formula 1)
Is obtained.

Further, the light receiving means 201A4 and the light receiving means 201A5 can be connected on the OE element 63. As a result, the sum of both light receiving means can be newly expressed as IA. Similarly, when the light receiving means 201B4 and the light receiving means 201B5 are connected, the sum of both light receiving means can be newly expressed as IB. Therefore, by substituting it into (Equation 1),
FE = IA−IB (Formula 2)
Is obtained.

  Using the FE detection logic according to (Equation 2) has the following effects. Originally, the grating A 71 and the grating B 72 are arcuate regions facing the tangential direction of the diffraction grating 70. Therefore, if the integrated optical member 20 is thermally expanded due to the influence of the heat generated by the laser element 13, the grating A71 and the grating B72 are arranged away from the center of the CD hologram 40. It is easy to cause a large change in position. However, the light receiving means 201A4, B4, A5, and B5 that receive the diffracted light from the grating A71 and the grating B72 are arranged in reverse order to take the sum, and the difference of the reverse order sums (tagged differential) is used as the FE detection logic. Therefore, the drift or offset of the detection signal caused by the above-described position change can be canceled by (Formula 2).

Similar to the FE detection logic described above, detection currents based on six types of lattice regions can be logically configured. That is, as tracking error (hereinafter abbreviated as TE) detection logic,
TE = IC−ID−k {(IE + IG) − (IF + IH)} (Formula 3)
(Where k is a constant determined according to the operation setting).

  Using the TE detection logic according to (Equation 3) has the following effects. First, since the light receiving means 201C and 201D detect the main beam, the first term and the second term of (Equation 3) are normal TE detection.

Next, the third term expressed in brackets of (Equation 3) is the grating C73 and the grating D74 of the diffraction grating 70.
Is obtained by obtaining the sum of the sub beam detection currents obtained from Therefore, similarly to the above-described FE detection logic, the drift or offset of the detection signal caused by the above-described position change is canceled by (Formula 3).

  In particular, since the grating A71 and the grating B72 are divided into arcuate regions, the incident shape of the diffracted light with respect to the sensor areas of the light receiving means 201A5, the light receiving means 201B5, the light receiving means 201A4, and the light receiving means 201B4 which are two-part light receiving means Light can be distributed without waste. Similarly, since the grating C73 and the grating D74 are divided into D-shaped regions, the incident shape can be distributed without waste to the sensor area of the light receiving means 201H from the light receiving means 201C which is an independent light receiving means. .

  Furthermore, since the area of the grating A71 to the grating D74 is configured to divide the entire region of the diffraction grating 70 into four equal parts, the diffraction grating 70 can be easily formed.

In addition, by configuring the diffraction grating as described above,
(IA5 + IB5) + (IA4 + IB4) ≈ (IC + ID) (Formula 4)
The optical power can be supplied in a well-balanced manner for RF signal detection and FE and TE signal detection.

The constant k is
k = (IC + ID) / (IE + IF + IG + IH) (Formula 5)
The amplification degree when OE conversion is performed in each light receiving means is adjusted so that normally k≈1.0. The three beams formed by the first diffraction grating 22 are formed in such a ratio that the optical power of the zeroth-order main beam is 10 and the optical power of the ± first-order subbeams is 1. Therefore, satisfying the condition of k≈1.0 after substituting the ratio of the optical power into the respective light receiving means in the above (Equation 5), compared with the amplification degree of the light receiving means 67A, 67B, the light receiving means 67E, 67F. , 67G, and 67H can be set to about 5 times.

  In (Equation 5), since the optical power of the sub beam of ± 1st order light is incident on the peripheral region of the diffraction grating 70, in addition to the optical power of the grating C73 and the grating D74, the optical power of the separation grating A75 to the separation grating D78. Is added, so the denominator increases. As a result, the amplification degree of the light receiving means 201E, 201F, 201G, and 201H can be set much lower than five times. Therefore, it is possible to realize a signal detection operation that is not easily affected by crosstalk.

  FIG. 6 shows a focus detection division pattern among the division patterns of the DVD hologram 6.

  The DVD hologram 6 is divided into two by a dividing line parallel to the radial direction of the optical disc, further divided into two by a dividing line parallel to the tangential direction, and is divided into four. The light diffracted by each divided area forms an image on a predetermined area on the light receiving means 201. The diffracted lights 411 and 412 generated by the divided area 311 and the divided area 312 shown in FIG. 6A form an image on the areas 511 and 512 on the light receiving means 201A2 and 201B1. Further, the diffracted lights 413 and 414 generated by the divided areas 313 and 314 are imaged on the areas 513 and 514 on the light receiving means 201A1 and 201B1.

  Further, the diffracted light 421 by the divided regions 321 and 323 shown in FIG. 6B forms an image on the region 521, and the diffracted light 422 by the divided regions 322 and 324 forms an image on the region 522.

These images are formed in any one of the light receiving means 201A1, 201A2, 201B1, 201B2, and 201B3 located at the center of the light receiving means 201, and the detection signals of the light receiving means are IA1, IA2, IB1, IB2, and IB3, respectively. When the focus error signal (FE) is
FE = (IA1 + IA2) − (IB1 + IB2 + IB3) (Formula 6)
Is calculated by the relational expression

  FIG. 7 shows a tracking detection division pattern among the division patterns of the DVD hologram 6.

  The DVD hologram 6 is divided into two by a dividing line parallel to the radial direction of the optical disc, further divided into two by a dividing line parallel to the tangential direction, and is divided into four. The light diffracted by each divided area forms an image on a predetermined area on the light receiving means 201. The diffracted light 431 by the divided region 331 shown in FIG. 7 forms an image on the region 531 on the light receiving unit 201β, and the diffracted light 432 by the divided region 332 forms an image on the region 532 on the light receiving unit 201α. Further, the diffracted light 433 by the divided region 333 forms an image on the region 533 of the light receiving unit 201D, and the diffracted light 434 by the divided region 334 forms an image on the region 534 on the light receiving unit 201C.

  FIG. 8 shows an example in which the focus detection division pattern and the tracking detection division pattern are formed as one DVD hologram 6.

  In FIG. 8, the DVD hologram 6 is divided into four zones, each of which is divided into four zones by a dividing line parallel to the radial direction of the optical disc and a dividing line parallel to the tangential direction. The tracking detection division pattern and the focus detection division pattern are formed for each zone.

  In the present embodiment, in order to cope with the change in the far field pattern (hereinafter abbreviated as “FFP”) of the laser light emitted from the laser light source of the DVD laser module 1 after the above-described division pattern is formed. The division pattern is formed.

  It has been confirmed that when the temperature of the laser light source rises due to laser light emission, the FFP of the emitted laser light deviates from that of the initial light emission. FIG. 9 shows a division pattern for making it possible to detect a tracking error even when such FFP deviation occurs.

  As shown in FIG. 9A, a divided area 351 and a divided area 352, which are areas divided by a dividing line parallel to the tangential direction of the DVD, sandwich a center line 353 in the radial direction of the DVD. Symmetrically formed, the diffracted light from the divided area 351 forms an image on the light receiving means 201H, and the diffracted light from the divided area 352 forms an image on the light receiving means 201G.

When the detection signals of the light receiving means 201C, 201E, 201G, 201D, 201F, 201H, 201α, and 201β are respectively IC, IE, IG, ID, IF, IH, Iα, and Iβ, the tracking error signal (TE) is
TE = (IC + Iα) − (ID + Iβ) −k {(IE + IG) − (IF + IH)} (Expression 7)
(Where k is a constant determined according to the operation setting)
Thus, a tracking error corresponding to the FFP shift can be detected.

  FIGS. 9B and 9C show an example in which a larger number of the above-described divided regions 351 and 352 are formed symmetrically across the center line in the radial direction of the DVD.

  FIG. 9B shows a case where a larger number of divided areas similar to the divided areas 351 and 352 shown in FIG. 9A are formed. FIG. 9C shows the area shown in FIG. Of the divided areas, only the part from the peripheral part is defined as a divided area 351 and a divided area 352. In any case, by forming a large number of divided areas 351 and 352, even if there are scratches on the optical disk, the influence of the reflected light from the optical disk due to the scratches can be dispersed, and the FFP can be displaced. Corresponding tracking error detection can be performed accurately.

FIG. 10 shows a state in which the tracking error balance is improved by the above-described means when an FFP shift occurs. FIG. 10 shows a case where the light beam spread in a plane parallel to the PN junction surface of the light emitting element is 14.1 deg and the light beam spread in a plane perpendicular to the PN junction surface of the light emitting element is 16.3 deg. In the example, the tracking error balance caused by the FFP deviation (Δθ _// ) is improved by the above-described means.

  INDUSTRIAL APPLICABILITY The present invention can be used as an optical pickup device used for recording and reproduction of an optical disc, and an optical disc device using the optical pickup device, and the detection optical system is not affected by fluctuations in operating temperature, and the cross It is possible to realize an optical pickup device capable of realizing a signal detection operation that is hardly affected by the talk, and an optical disk device using the optical pickup device.

The figure which shows the structure of the optical pick-up apparatus which concerns on embodiment of this invention. The figure which shows the structure of an integrated optical member The figure which shows the optical path in the integrated optical member until it enters the light receiver Overall perspective view of the receiver The figure which shows the division | segmentation pattern of the hologram for CD, and the pattern of the OE element provided in the light receiver The figure which shows the division pattern for focus detection among the division patterns of the hologram for DVD The figure which shows the division pattern for tracking detection among the division patterns of the hologram for DVD The figure which shows an example of the division | segmentation pattern of the hologram for DVD The figure which shows the division | segmentation pattern for enabling tracking error to be detected even if the shift | offset | difference of FFP of the emitted laser beam arises The figure which shows a mode that tracking error detection is improved when the shift | offset | difference of FFP of the emitted laser beam arises.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 DVD laser module 2 Reflecting mirror 3 Collimating lens 4 Beam splitter 5 Rising prism 6 DVD hologram 7 Objective lens 8 Optical disk 9 Lens 10 CD light source 11 Semiconductor laser 13 Laser element 18 Lead 19 Light emitting point 20 Integrated optical member 21 First light guide member 22 First diffraction grating 23 Light absorption film 25 Second light guide member 26 Slope 27 Wavelength selection film 30 Third light guide member 31 First slope 32 Second slope 33 Broadband polarization separation film 35 Fourth light guide Member 36 First slope 37 Second slope 38 Transmission surface 39 Outgoing surface 40 CD hologram 41 APC reflection film 45 Fifth light guide member 46 Slope 47 First surface 48 Second surface 49 Light absorption film 60 Light receiver 61 Package 62 Incident Port 63 OE element 64 Lead terminal 65 Flexible cable 70 times Lattice 71 lattice A
72 lattice B
73 lattice C
74 Grid D
75 Separation grid A
76 Separation grid B
77 Separation grid C
78 Separation grid D
80 Coupling member 101 Diffused light 102 Forward light for CD 104 Return light for CD 105 Reflected diffracted light for CD 110 Return light for DVD 201A1, 201A2, 201A4, 201A5, 201B1, 201B2, 201B3, 201B4, 201B5, 201C, 201D, 201E, 201F, 201G, 201H, 201α, 201β Light receiving means 311, 312, 313, 314, 321, 322, 323, 324, 331, 332
, 333, 334, 351, 352 Divisional area 353 Center line 411, 412, 413, 414, 421, 422, 431, 432, 433, 434
Diffracted light 511,512,513,514,521,522,531,532,533,534
region

Claims (11)

A CD hologram having a split surface for extracting a light beam necessary for tracking control and focus control from the reflected light emitted from the CD light source and reflected by the CD;
A DVD hologram having a split surface for extracting light flux necessary for tracking control and focus control from the reflected light emitted from the DVD light source and reflected by the DVD;
A light receiving means for receiving light diffracted by the hologram for DVD and converting it into an electrical signal;
With
The light receiving means receives diffracted light of a region divided by a dividing line parallel to the radial direction of the DVD and a dividing line parallel to the tangential direction of the DVD for extracting a light beam necessary for the focus control. When the detection signals of the light receiving means are IA1, IA2, IB1, IB2, and IB3, respectively, the focus error signal (FE) is FE = (IA1 + IA2) − (IB1 + IB2 + IB3).
An optical pickup device characterized by being calculated by the following relational expression . A CD hologram having a split surface for extracting a light beam necessary for tracking control and focus control from the reflected light emitted from the CD light source and reflected by the CD;
A DVD hologram having a split surface for extracting light flux necessary for tracking control and focus control from the reflected light emitted from the DVD light source and reflected by the DVD;
A light receiving means for receiving light diffracted by the hologram for DVD and converting it into an electrical signal;
With
The light receiving means extracts a light beam necessary for the tracking control, diffracted light of a region divided by a dividing line parallel to the radial direction of the DVD and a dividing line parallel to the tangential direction of the DVD, and for DVD 8 pieces of diffracted light received in a region divided by a dividing line parallel to the tangential direction of the DVD to extract a light beam necessary for tracking control in consideration of a deviation of the emission pattern of the laser light emitted from the light source When the detection signals of the light receiving means are IC, IE, IG, ID, IF, IH, Iα, Iβ, respectively, the tracking error signal (TE)
TE = (IC + Iα) − (ID + Iβ) −k {(IE + IG) − (IF + IH)} (where k is a constant determined according to the operation setting)
An optical pickup device characterized by being calculated by the following relational expression . The hologram for CD is divided into a central region divided into three by two dividing lines parallel to the radial direction of the CD and two arcuate regions separated in the tangential direction, and the central region is further divided into tangential CDs. It is divided into substantially D-shaped regions that are further divided into two by a dividing line parallel to the direction, and the entire region of the CD hologram is divided into two arcuate regions and two substantially D-shaped regions by an H-shaped dividing line. 3. The optical pickup device according to claim 1, wherein the optical pickup device is divided into approximately four equal areas. 4. The optical pickup device according to claim 3, wherein a separation grating that diffracts in the same direction as the substantially D-shaped region is formed in each of the two arcuate regions. The CD hologram has a plurality of optical surfaces formed inside an integrated optical member having a function of guiding a light beam emitted from a light emitting element of a light source for CD to a CD and separating a necessary light beam from reflected light from the CD. the optical pickup apparatus according to claim 1, characterized in that formed on either 4. The light receiving means for receiving the light diffracted by the CD hologram and converting it into an electrical signal includes a first arcuate region and a second arcuate region obtained by separating the CD hologram in a tangential direction, and a first approximately Two light receiving means for receiving the diffracted light of the first arcuate region and two of receiving the diffracted light of the second arcuate region for the D-shaped region and the second substantially D-shaped region Light receiving means, three light receiving means for receiving diffracted light of the first substantially D-shaped region, and three light receiving means for receiving diffracted light of the second substantially D-shaped region. The optical pickup device according to claim 1, wherein: Light receiving means for receiving light diffracted by the CD hologram and converting it into an electrical signal, wherein the detection signals of the two light receiving means for receiving the diffracted light of the first arcuate region are respectively IA4 and IB4 When the detection signals of the two light receiving means arranged in reverse order for receiving the diffracted light of the second arcuate region are IA5 and IB5, respectively, the focus error signal (FE) is
FE = (IA4 + IA5) − (IB4 + IB5)
7. The optical pickup device according to claim 6, wherein the optical pickup device is calculated by the following relational expression. Light receiving means for receiving light diffracted by the hologram for CD and converting it into an electrical signal, each of the detection signals of the three light receiving means for receiving diffracted light of the first substantially D-shaped region, respectively. When the detection signals of the three light receiving means that receive the diffracted light of the second substantially D-shaped region are ID, IF, and IH, respectively, and IC, IE, and IG, the tracking error signal (TE)
TE = IC-ID-k {(IE + IG)-(IF + IH)}
(Where k is a constant determined according to the operation setting)
7. The optical pickup device according to claim 6, wherein the optical pickup device is calculated by the following relational expression. 9. An optical disk device using the optical pickup device according to claim 1. It has a dividing surface for extracting light beams necessary for tracking control and focus control from the reflected light emitted from the light source for CD for irradiating the CD with laser light to record and reproduce information and reflected by the CD. CD hologram,
It has a dividing surface for extracting light beams necessary for tracking control and focus control from reflected light emitted from a DVD light source for irradiating a DVD with laser light and recording and reproducing information. A DVD hologram,
In the DVD hologram, a region divided by a dividing line parallel to the radial direction of the DVD and a dividing line parallel to the tangential direction of the DVD for extracting a light beam necessary for focus control is formed,
The light receiving means for receiving the light diffracted by the DVD hologram and converting it into an electrical signal is for extracting a light beam necessary for the focus control and a dividing line parallel to the radial direction of the DVD and the tangential direction of the DVD A focus error detection method for an optical pickup device formed by five light receiving means for receiving diffracted light in a region divided by a dividing line parallel to
Five light receiving means for receiving diffracted light in a region divided by a dividing line parallel to the radial direction of the DVD and a dividing line parallel to the tangential direction of the DVD for extracting a light beam necessary for the focus control When the detection signals of IA1, IA2, IB1, IB2, and IB3 are respectively, the focus error signal (FE) is
FE = (IA1 + IA2) − (IB1 + IB2 + IB3)
A focus error detection method characterized in that it is calculated by the following relational expression. It has a dividing surface for extracting light beams necessary for tracking control and focus control from the reflected light emitted from the light source for CD for irradiating the CD with laser light to record and reproduce information and reflected by the CD. CD hologram,
It has a dividing surface for extracting light beams necessary for tracking control and focus control from reflected light emitted from a DVD light source for irradiating a DVD with laser light and recording and reproducing information. A DVD hologram,
The DVD hologram includes an area divided by a dividing line parallel to the radial direction of the DVD and a dividing line parallel to the tangential direction of the DVD for extracting a light beam necessary for tracking control, and the DVD light source. A region divided by a dividing line parallel to the tangential direction of the DVD for extracting a light beam necessary for tracking control in consideration of a deviation of an emission pattern of the laser light emitted from the DVD,
The light receiving means for receiving the light diffracted by the DVD hologram and converting it into an electric signal is for extracting a light beam necessary for the tracking control and a dividing line parallel to the radial direction of the DVD and the tangential direction of the DVD In the tangential direction of the DVD for extracting the luminous flux necessary for tracking control considering the deviation of the diffracted light of the region divided by the dividing line parallel to the laser beam and the emission pattern of the laser light emitted from the DVD light source. A tracking error detection method for an optical pickup device formed by eight light receiving means for receiving diffracted light in a region divided by parallel dividing lines,
Diffraction light of a region divided by a dividing line parallel to the radial direction of the DVD and a dividing line parallel to the tangential direction of the DVD for extracting the light flux necessary for the tracking control, and emitted from the light source for DVD The eight light receiving means for receiving the diffracted light in the region divided by the dividing line parallel to the tangential direction of the DVD for extracting the light flux necessary for the tracking control considering the deviation of the emission pattern of the laser light. When the detection signals are IC, IE, IG, ID, IF, IH, Iα, Iβ, respectively, the tracking error signal (TE)
TE = (IC + Iα) − (ID + Iβ) −k {(IE + IG) − (IF + IH)}
(Where k is a constant determined according to the operation setting)
A tracking error detection method characterized in that it is calculated by the relational expression:

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