JP2005293658A - Optical pickup and optical disc apparatus - Google Patents

Abstract

Provided are an optical pickup and an optical disc apparatus that can easily adjust the light emission intensity of a laser light source when one laser light source is used for both recording and reproduction and the other laser light source is used only for reproduction. For the purpose.
A light receiving sensor that controls the light emission intensity of a laser beam emitted from a light source when the first light source performs both recording and reproduction and the second light source performs only reproduction. Output level adjusting means for setting the output level converted at 102 based on the light receiving level of the second light source within the range of the output level based on the light receiving level of the first light source.
[Selection] Figure 1

Description

  The present invention relates to an optical disk device mounted on an electronic device such as a personal computer, a notebook computer, or a mobile terminal device, and an optical pickup suitably used for the optical disk device.

  Various optical discs such as a DVD (Digital Versatile Disc), a CD-R (writable compact disc), and a CD-RW (rewritable compact disc) have been developed as optical recording media. In a DVD, information is recorded or reproduced by a laser beam having a wavelength of about 650 nm. On the other hand, in CD-R and CD-RW, information is recorded or reproduced by laser light having a wavelength of about 780 nm. An optical disc apparatus that records or reproduces information on a plurality of types of optical discs has been proposed.

  Further, in such an optical disc apparatus that records or reproduces information on a plurality of types of optical discs, a single laser element that emits light beams of different wavelengths is used as a light source of an optical pickup mounted on the optical disc apparatus. A so-called hybrid type two-wavelength semiconductor laser arranged adjacent to a package is described in (Patent Document 1), and a light source having a plurality of wavelengths is integrated on a single semiconductor substrate (so-called monolithic type). A two-wavelength semiconductor laser) is used.

  An example of an optical system of an optical pickup using the above-described hybrid type two-wavelength semiconductor laser as a light source is shown in FIG.

  In FIG. 1, the light emitted from the light source 1 passes through the optical members 4 and 5, enters the collimator lens 100, is reflected by the beam splitter plate 101 (BS plate), and is guided to the rising prism 103. At this time, a part of the emitted light is transmitted through the BS plate 101 and guided to the light receiving sensor 102 that monitors the light amount of the light source 1, and the light emission power of the light source 1 is adjusted by the output of the light receiving sensor 102.

The light from the beam splitter plate 101 is reflected by the surface 103a of the rising prism 103, is further reflected by the surface 103b, passes through the surface 103a, enters the hologram 104 sandwiching the liquid crystal, and is guided to the objective lens 105. It is condensed on the optical disk 106. The light reflected by the optical disk 106 is guided to the rising prism 103 via the objective lens 105 and the hologram, passes through the surface 103a, is reflected by the surface 103b, is further reflected by the surface 103a, and is guided to the beam splitter plate 101. The light is reflected by the beam splitter plate 101, passes through the collimator lens 100, enters the optical member 5, and reaches the light receiving element 2.
JP-A-10-241189

  In the optical pickup described above, the light emission intensity is adjusted independently by the light receiving sensor 102 for each of the two types of laser beams having different wavelengths, that is, the laser beam for CD and the laser beam for DVD. However, the above two types of laser beams have different emission intensity wavelength dependencies, and adjusting each of them independently complicates the adjustment means.

  The present invention has been made in order to solve the above-described problem. In the case where one laser light source is used for both recording and reproduction, and the other laser light source is used only for reproduction, the emission intensity of the laser light source. It is an object of the present invention to provide an optical pickup and an optical disc apparatus that can easily adjust the above.

  The present invention has been made in order to solve the above-described problems. In an optical pickup that records and reproduces information by irradiating an optical disc with laser light using a plurality of light sources that emit laser light having different wavelengths. When the first light source performs both recording and reproduction, and the second light source performs only reproduction, the second light source is converted by a light receiving sensor that controls the emission intensity of the laser light. An optical pickup comprising output level adjusting means for setting an output level based on a light reception level of a light source within a range of a light reception level of a first light source.

  The required light intensity differs between recording and reproduction, and since the first light source performs both recording and reproduction, the emission intensity needs to have a predetermined width. Since the light source performs only reproduction, the emission intensity can be limited to a certain value. For this reason, the output level adjusting means for setting the output level based on the light receiving level of the second light source converted by the light receiving sensor within the range of the output level based on the light receiving level of the first light source has two types. The light emission intensity of the second light source can also be adjusted by performing only the adjustment in the first light source circuit without performing the adjustment in the light source circuit independently.

  According to the present invention, by having the output level adjusting means for setting the output level converted by the light receiving sensor based on the light receiving level of the second light source within the range of the output level based on the light receiving level of the first light source. The light emission intensity of the second light source can also be adjusted by performing only the adjustment in the first light source circuit without separately adjusting in the two types of light source circuits.

  A first invention of the present application is an optical pickup that records and reproduces information by irradiating an optical disc with laser light using a plurality of light sources that emit laser light having different wavelengths. When the second light source performs only reproduction, the output level based on the light reception level of the second light source converted by the light reception sensor that controls the light emission intensity of the laser light is An optical pickup comprising output level adjusting means for setting within an output level range based on the light reception level of the first light source.

  The required light intensity differs between recording and reproduction, and since the first light source performs both recording and reproduction, the emission intensity needs to have a predetermined width. Since the light source performs only reproduction, the emission intensity can be limited to a certain value. For this reason, the output level adjusting means for setting the output level based on the light receiving level of the second light source converted by the light receiving sensor within the range of the output level based on the light receiving level of the first light source has two types. The light emission intensity of the second light source can also be adjusted by performing only the adjustment in the first light source circuit without performing the adjustment in the light source circuit independently.

A second invention of the present application is characterized in that, in the first invention, the output level adjusting means is an optical film whose light transmission characteristics when laser light is transmitted have wavelength dependency. By receiving the laser light transmitted through the optical film having such light transmission characteristics by the light receiving sensor, the output level of the second light source converted by the light receiving sensor is within the range of the output level of the first light source. Can be set to

  According to a third invention of the present application, in the first invention, the output level adjusting means is a photoelectric conversion means for converting into a current value corresponding to the intensity of the laser beam received by the light receiving sensor. By considering the conversion efficiency of the photoelectric conversion means, the current value according to the light reception intensity of the second light source received by the light receiving sensor is set within the range of the current value according to the light reception intensity of the first light source. Can do.

  According to a fourth aspect of the present invention, in the first aspect, the first light source is a CD light source, and the second light source is a DVD light source. As a result, the light emission intensity of the DVD light source can be automatically controlled by adjusting the CD light source circuit without separately adjusting the two types of light source circuits.

  A fifth invention of the present application is an optical disk device using the optical pickups of the first to fourth inventions. By using this optical pickup, it is possible to realize an optical disc apparatus capable of easily adjusting the emission intensity in an optical disc apparatus having two types of light sources having different emission wavelengths.

  FIG. 1 is a diagram showing an optical system configuration of an optical pickup according to an embodiment of the present invention. FIG. 2A shows components of the optical pickup according to the embodiment of the present invention, and FIG. 2B shows a carriage formed by incorporating these components.

  The light source 1 accommodates a CD semiconductor laser that emits laser light having a wavelength of about 780 nm and a DVD semiconductor laser that emits laser light having a wavelength of about 650 nm. In FIG. 1, the optical path of the laser beam for CD is indicated by a broken line, and the optical path of the laser beam for DVD is indicated by a solid line. The optical members 4 and 5 shown in FIG. 1 are fixed in the coupling base 3 shown in FIG.

  The light emitted from the light source 1 passes through the optical members 4 and 5, enters the collimator lens 100, is reflected by the beam splitter plate 101 (BS plate), and is guided to the rising prism 103. At this time, a part of the emitted light is transmitted through the BS plate 101 and guided to the light receiving sensor 102 that monitors the light amount of the light source 1, and the light emission power of the light source 1 is adjusted by the output of the light receiving sensor 102.

  The light from the beam splitter plate 101 is reflected by the surface 103a of the rising prism 103, is further reflected by the surface 103b, passes through the surface 103a, enters the hologram 104 sandwiching the liquid crystal, and is guided to the objective lens 105. It is condensed on the optical disk 106. The light reflected by the optical disk 106 is guided to the rising prism 103 via the objective lens 105 and the hologram, passes through the surface 103a, is reflected by the surface 103b, is further reflected by the surface 103a, and is guided to the beam splitter plate 101. The light is reflected by the beam splitter plate 101, passes through the collimator lens 100, enters the optical member 5, and reaches the light receiving element 2.

  The beam splitter plate 101 is formed with an optical film having a wavelength-dependent transmission characteristic shown in FIG. 3, and the light receiving sensor 102 is transmitted through the optical film through the CD laser light and the DVD laser light. The intensity of the laser beam received by is adjusted.

In the optical pickup according to the embodiment of the present invention, it is assumed that the CD laser beam is used for both reproducing and recording information, and the DVD laser beam is used only for reproducing information. The required laser light intensity differs between information recording and reproduction. Therefore, in order to perform both information reproduction and recording, the intensity of the CD laser light may have a predetermined width. is necessary. On the other hand, the intensity of the DVD laser light used only for reproduction can be limited to a certain value. In the embodiment of the present invention, the optical film having the above-described characteristics is used to adjust the output level corresponding to the light receiving level of the DVD laser light obtained by conversion by the light receiving sensor 102, and thereby the DVD laser. The intensity of the light is set within a predetermined range of the intensity of the laser beam for CD.

  FIG. 4 is a diagram illustrating an example of the wavelength dependence of the light receiving sensitivity of the light receiving sensor 102. In this example, the light receiving sensitivity is set to be maximum in the vicinity of 660 nm which is the wavelength of the DVD laser beam. Thus, based on the wavelength dependence of the light receiving sensitivity of the light receiving sensor 102, the photoelectric conversion means of the light receiving sensor 102 sets the current value according to the light receiving level of the laser beam for DVD, and is converted into the current value. It becomes possible to set the output level of the DVD laser beam within the range of the light receiving level of the CD laser beam.

  FIG. 5 is a block diagram of laser light control in the light receiving sensor 102. FIG. 5A shows a conventional case, and FIG. 5B shows a case of the embodiment of the present invention.

  In the conventional case, laser driver circuits 13 and 14 are connected to the CD laser light source 11 and the DVD laser light source 12, respectively, and the intensity of the laser light emitted from the CD laser light source 11 and the DVD laser light source 12 is as follows. The light-current conversion element 16 of the light receiving sensor 102 converts the current value into a current value corresponding to the received light intensity. The obtained current value is converted into a voltage by the current-voltage conversion circuit 17, and the amplification degree is adjusted by the amplification degree adjuster 19 for each of CD and DVD by the CD / DVD changeover switch 18. As a result, the laser power control circuit 15 controls the intensities of the laser beam for CD and the laser beam for DVD separately and independently.

  On the other hand, in the embodiment of the present invention, laser driver circuits 13 and 14 are connected to the CD laser light source 11 and the DVD laser light source 12, respectively, and emitted from the CD laser light source 11 and the DVD laser light source 12. The intensity of the laser light is converted into a current value by the light-current conversion element 16 of the light receiving sensor 102. The current value obtained here is converted into a voltage by the current-voltage conversion circuit 17, and the output level after conversion of the DVD laser beam is the same as the output level after conversion of the CD laser beam by the above-mentioned means. Since it is preset so as to be within the range, the amplification degree adjuster 19 does not require the CD / DVD changeover switch 18 and does not require a switching operation as in the conventional case, but only for the CD, by the amplification degree adjuster 19. Is adjusted. Thereby, in the embodiment of the present invention, the laser power control circuit 15 adjusts at least one of the intensity of the laser beam for CD and the intensity of the laser beam for DVD only by adjusting the amplification degree only for the CD. be able to.

  FIG. 6 is a diagram showing an optical disc apparatus using an optical pickup according to an embodiment of the present invention. In FIG. 6, reference numeral 200 denotes a casing, and the casing 200 is configured by combining an upper casing portion 200a and a lower casing portion 200b. The upper housing part 200a and the lower housing part 200b are fixed to each other using a spiral or the like. Reference numeral 201 denotes a tray that can be freely moved in and out of the housing 200, 202 is a spindle motor provided in the tray 201, 203 is an optical pickup, and the optical pickup 203 is at least one of an operation for writing information to or reading information from an optical disc. I do. The optical pickup 203 is mounted on a carriage (not shown) held so as to be movable in the radial direction of the optical disc. Reference numeral 204 denotes a bezel provided on the front end surface of the tray 201. The bezel 204 is configured to close the entrance / exit 205 of the tray 201 when the tray 201 is stored in the housing 200.

Reference numerals 206 and 207 denote rails slidably attached to both the tray 201 and the casing 200. The rails 206 and 207 are provided on both sides of the tray 201. A tray 201 is attached in a direction so as to be able to appear and retract.

  An eject switch 208 is provided on the bezel 204 provided on the front end surface of the tray 201. By pressing the eject switch 208, an engagement portion (not shown) provided on the housing 200 and the tray 201 are provided. The engagement with the provided engaging portion (not shown) is released.

  INDUSTRIAL APPLICABILITY The present invention can be used as an optical disk device mounted on an electronic device such as a personal computer, a notebook computer, a mobile terminal device, and an optical pickup suitably used for the optical disk device, and easily adjusts the light emission intensity. An optical disc device that can be performed can be realized.

The figure which shows the optical system structure of the optical pick-up concerning embodiment of this invention The figure which shows the component of the optical pick-up concerning embodiment of this invention The figure which shows the wavelength dependence of the light transmission characteristic of the optical film The figure which shows an example of the wavelength dependence of the light reception sensitivity of a light reception sensor Block diagram of laser light control in light receiving sensor The figure which shows the optical disk apparatus using the optical pick-up in one embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Light receiving element 3 Coupling base 4 Optical member 5 Optical member 11 Laser light source for CD 12 Laser light source for DVD 13, 14 Laser driver circuit 15 Laser power control circuit 16 Light-current conversion element 17 Current-voltage conversion circuit 18 CD / DVD changeover switch 19 Amplification adjuster 100 Collimator lens 101 Beam splitter plate 102 Light receiving sensor 103 Rising prism 103a Surface 103b Surface 104 Hologram 105 Objective lens 106 Optical disk 200 Housing 200a Upper housing portion 200b Lower housing portion 201 Tray 202 Spindle Motor 203 Optical pickup 204 Bezel 205 In / out port 206, 207 Rail 208 Eject switch

Claims (5)

In an optical pickup that records and reproduces information by irradiating an optical disc with laser light using a plurality of light sources that emit laser beams having different wavelengths, the first light source performs both recording and reproduction. When the second light source performs only reproduction, the output level based on the light reception level of the second light source, which is converted by the light reception sensor that controls the light emission intensity of the laser light, is the light reception level of the first light source. An optical pickup comprising output level adjusting means for setting within an output level range based on the above. 2. The optical pickup according to claim 1, wherein the output level adjusting means is an optical film whose light transmission characteristic when laser light is transmitted has wavelength dependency. 2. The optical pickup according to claim 1, wherein the output level adjusting means is a photoelectric conversion means for converting into a current value corresponding to the intensity of the laser beam received by the light receiving sensor. 2. The optical pickup according to claim 1, wherein the first light source is a CD light source, and the second light source is a DVD light source. 5. An optical disc apparatus using the optical pickup according to claim 1.

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