JP2006114157A - Optical integrated device, optical pickup device, and optical information recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve S/N of a RF signal in an optical information recording and reproducing device which is adaptable to a BD(high density optical information recording medium by blue-light), a DVD, and a CD. <P>SOLUTION: This apparatus has two wavelength light receiving and emitting integrated element 3A and one wavelength light receiving and emitting integrated element 3B, wherein the two wavelength light receiving and emitting integrated element 3A is constituted of a first wavelength light source corresponding to the BD, a two wavelength light source part 3SA having a second wavelength light source corresponding to the DVD of longer wavelength, a micro-prism, and a two wavelength light receiving part PDA by which return light from a medium is guided and detected, and the one wavelength light receiving and emitting integrated element 3B is constituted of a third wavelength corresponding to a CD medium having longer wavelength than the first and the second wavelength, a micro-prism, and a one wavelength light receiving part PDB by which return light from the medium is guided and detected, the light receiving part PDA of the two wavelength light receiving and emitting integrated element 3A has constitution having a light receiving element PD13 for RF signal separately from a light receiving element for taking out a servo signal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical integrated device, an optical pickup device, and an optical information recording / reproducing device, and in particular, to three types of optical information recording media in which different first wavelengths, second wavelengths, and third wavelengths are used. The present invention relates to an optical integrated device for performing recording or / and reproduction, an optical pickup device including the optical integrated device, and an optical information recording / reproducing device.

In recent years, an optical information recording / reproducing apparatus using, for example, a Blu-ray Disc of a high-density optical information recording medium (hereinafter referred to as BD) compatible with blue laser light has been remarkably widespread. In the optical information recording / reproducing apparatus for recording or / and reproducing the BD, recording or / and reproducing for the CD (Compact Disc) and the DVD (Digital Versatile Disc) of the optical information recording medium in other formats is also possible. An optical information recording / reproducing apparatus that can be used has been put into practical use.
Since these CDs, DVDs, and BDs use three types of laser beams of about 780 nm, about 650 nm, and about 405 nm, respectively, in the recording / reproducing apparatus for these three types of optical information recording media, In particular, wavelength light having a large difference between CD and BD is handled.

  This three-wavelength optical information recording / reproducing apparatus includes, for example, a configuration in which three types of pickups that are substantially independent from each other corresponding to each of these wavelengths are incorporated, or a two-wavelength pickup for CD and DVD, for example. It is configured to incorporate a Blu-ray pickup that is substantially independent from this.

Further, as another configuration of the optical information recording / reproducing apparatus corresponding to the three wavelengths, one light emitting / receiving element is configured for two short wavelengths out of the three wavelengths, and independently of these two wavelengths, a longer wavelength is formed. Proposals have been made for a configuration in which one light emitting and receiving element for another wavelength is provided (see, for example, Patent Document 1), or an objective lens corresponding to three wavelengths. In contrast, light sources having three independent wavelengths are proposed. Have been proposed (see, for example, Patent Document 2), in which the wavelength light from these is made to coincide with the axis of a common objective lens.
JP 2004-103145 A Japanese Patent Application Laid-Open No. 2004-6005

As described above, an optical pickup and an optical information recording / reproducing apparatus capable of recording and / or reproducing optical information with compatibility with respect to three types of optical information recording media corresponding to wavelengths, for example, BD, CD, and DVD Various applications and proposals have been made.
However, in these, there is a problem that the S / N becomes low in the recording detection of, for example, BD corresponding to a short wavelength, that is, RF (high frequency) signal reproduction detection.
This is because the return light of each wavelength from the optical information recording medium is detected by a required divided photodiode, a tracking servo signal and a focusing servo signal are obtained by calculation, and the sum of the detection signals from these divided photodiode elements. Since the RF signal is the RF signal, the noise signal is the sum of the noise signals in each photodiode element, and the noise becomes large, and the photodiode itself has low sensitivity to short wavelengths, so that the S / N of the RF signal is reduced. Will decrease.

  The present invention provides an optical light emitting / receiving device, an optical pickup device, and an optical information recording / reproducing device that can take a simple configuration and improve the S / N ratio of an RF signal.

  An optical integrated device according to the present invention includes a two-wavelength light receiving / emitting integrated element and a one-wavelength light receiving / emitting integrated element, and the two-wavelength light receiving / emitting integrated element has a first wavelength light corresponding to the first optical information recording medium. A two-wavelength light source unit having a light source and a second wavelength light source corresponding to the second optical information recording medium having a longer wavelength than the first wavelength light; a microprism; And a two-wavelength light receiving portion that is detected by introducing return light of the first and second wavelength light from the first and second optical information recording media. A one-wavelength light source unit for a third wavelength light corresponding to a third optical information recording medium having a longer wavelength than the first and second wavelengths, and the third optical information recording medium from the third optical information recording medium. A two-wavelength light receiving and emitting integrated circuit, comprising a one-wavelength light receiving portion that is detected by introducing return light of a wavelength. The light-receiving portion of the child, and a light receiving element for servo signal output, the light receiving element separately, characterized by comprising a light receiving element of the high-frequency recording information detection only.

  An optical pickup device according to the present invention includes an objective lens and an optical integrated device, and the optical integrated device includes a two-wavelength light receiving / emitting integrated element and a one wavelength light receiving / emitting integrated element. The element includes a light source of first wavelength light corresponding to the first optical information recording medium, and a light source of second wavelength light corresponding to the second optical information recording medium having a longer wavelength than the first wavelength light. A two-wavelength light source unit including: a microprism; and two wavelengths detected by introducing the return light of the first and second wavelength light from the first and second optical information recording media by the microprism The one-wavelength light receiving / emitting integrated element has one wavelength of the third wavelength light corresponding to the third optical information recording medium having a longer wavelength than the first and second wavelengths. Return light of the third wavelength from the light source unit and the third optical information recording medium is introduced. A single-wavelength light receiving portion to be detected, and the light-receiving portion of the two-wavelength light receiving and emitting integrated element is separate from the light receiving element for servo signal extraction and the light receiving element and is dedicated to detecting high-frequency recording information. And a light receiving element.

  An optical information recording / reproducing apparatus according to the present invention includes a rotation driving device that rotates and drives a first optical information recording medium, a second optical information recording medium, and a third optical information recording medium, and an optical pickup device. The optical pickup device includes an objective lens and an optical integrated device, and the optical integrated device includes a two-wavelength light receiving / emitting integrated element and a one wavelength light receiving / emitting integrated element. The light receiving / emitting integrated element includes a two-wavelength light receiving / emitting integrated element and a one-wavelength light receiving / emitting integrated element, and the two-wavelength light receiving / emitting integrated element includes a first wavelength light source corresponding to the first optical information recording medium, A two-wavelength light source unit having a light source of a second wavelength light corresponding to a second optical information recording medium having a longer wavelength than the first wavelength light; a microprism; The first and second wavelengths of light from the second optical information recording medium; A single-wavelength light receiving / emitting integrated element having a longer wavelength than the first and second wavelengths, and a third optical information recording unit having a longer wavelength than the first and second wavelengths. A one-wavelength light source unit for the third wavelength light corresponding to the medium, and a one-wavelength light receiving unit for detecting the return light of the third wavelength from the third optical information recording medium. The light receiving unit of the two-wavelength light receiving / emitting integrated element includes a light receiving element for extracting a servo signal and a light receiving element dedicated to high-frequency recording information detection separately from the light receiving element. Recording or / and reproduction on a recording medium is performed.

Further, the present invention is the optical integrated device described above, and further in the optical integrated device in the optical pickup device and the optical information recording / reproducing device described above, wherein the first optical information recording medium is an optical disc compatible with blue laser light, The second optical information recording medium is a DVD (Digital Versatile Disc), and the third optical information recording medium is a CD (Compact Disc).
The present invention also relates to the above-described optical integrated device, and further to the optical integrated device in the above-described optical pickup device and optical information recording / reproducing device, wherein the two-wavelength light source unit of the two-wavelength light receiving and emitting integrated element is the first optical device. A first semiconductor laser unit that emits a laser beam having a wavelength and a second semiconductor laser unit that emits a laser beam having the second wavelength are stacked, and the two-wavelength light receiving unit includes A light receiving element for extracting servo signals common to the second wavelength light and a light receiving element dedicated for detecting the high frequency recording information are provided.
Furthermore, the present invention is the above-described optical integrated device, and further the optical integrated device in the above-described optical pickup device and optical information recording / reproducing device, wherein the two-wavelength light source section of the two-wavelength light receiving and emitting integrated element is the first optical device. A first semiconductor laser section that emits laser light having a wavelength and a second semiconductor laser section that emits laser light having the second wavelength are arranged close to each other, and the first semiconductor laser section of the two-wavelength light receiving section is formed. And a light receiving element for extracting a servo signal for the second wavelength light and a light receiving element dedicated for detecting the high-frequency recording information are juxtaposed in correspondence with the first and second semiconductor laser units arranged close to each other. It is characterized by that.

  Further, the present invention is the above-described optical pickup device and optical information recording / reproducing device, wherein the objective lens includes the first wavelength light, the second wavelength light from the two-wavelength light receiving and emitting integrated element, and 1 It is characterized by comprising a three-wavelength compatible objective lens common to the third wavelength light from the wavelength receiving / emitting integrated element.

As described above, the optical integrated device according to the present invention has two light receiving / emitting integrated element configurations including a two-wavelength light receiving / emitting integrated element and a one wavelength receiving / emitting integrated element. Since the first and second wavelength lights having a short wavelength are paired, the optical design in the two-wavelength light receiving / emitting integrated element, for example, the design of the microprism is easy to take. In spite of the two light receiving / emitting element configurations of the element and the one-wavelength light receiving / emitting integrated element, an optical integrated device having excellent optical characteristics can be configured.
The single-wavelength light receiving / emitting integrated element can be constituted by the single-wavelength light receiving / emitting integrated element which has been sufficiently researched and developed as a CD recording / reproducing apparatus, so that the design and manufacture can be simplified. .

Further, in the above-described configuration, in the two-wavelength light receiving / emitting integrated element, that is, the light receiving / emitting integrated element that handles two short wavelengths, it is dedicated to the detection of the high frequency recording information signal (RF signal) separately from the light receiving element for extracting the servo signal. By providing the light receiving element, the S / N ratio of the RF signal can be improved.
That is, in a normal configuration, a light receiving element for taking out a servo signal, specifically, a tracking error signal for tracking servo and focusing servo, and a photodiode as a light receiving element for obtaining a focusing error signal are used as these signals. Therefore, the RF signal is obtained by the sum of signals from these divided photodiodes. For this reason, the total noise including noise components included in each signal component, for example, noise components accompanying amplification of these signals, becomes the noise component of the RF signal, and the photoelectric conversion efficiency of the photodiode of the light receiving element for short wavelengths is increased. Since the signal component of the RF signal is small and S / N is low.
On the other hand, the present invention has a configuration in which, apart from the light receiving element for obtaining the servo signal detection signal, a light receiving element dedicated to high frequency recording information detection is provided for the above-described two wavelengths. Further, for example, the light receiving element dedicated to detection of high-frequency recording information can be a single light receiving element that does not depend on a split photodiode, so that the amount of RF signal can be sufficiently increased. N can be improved.

  As described above, the light receiving element dedicated to the detection of the high frequency recording information is formed in the light receiving portion having the light receiving element for taking out the servo signal in the two-wavelength light receiving and emitting integrated element relating to the first and second two wavelengths. In the present invention, the light receiving elements are formed on a common semiconductor substrate. In this way, the light receiving elements can be formed at the same time, and the structure is simplified. The necessity of a special manufacturing method and manufacturing process by providing a light receiving element dedicated to high-frequency recording information detection is avoided.

  In the optical pickup apparatus and the optical information recording / reproducing apparatus according to the present invention, the objective lens is constituted by a common objective lens set for the first to third wavelength lights. In addition to simplification of design and manufacturing, it is possible to further simplify the configuration, improve the number of parts, assembling accuracy, etc., reduce the size and weight, and further reduce the cost by simplifying assembly manufacturing.

Further, according to the optical integrated device, the optical pickup device, and the optical information recording / reproducing device according to the present invention, the first optical information recording medium using the short wavelength light, for example, a BD such as a Blu-ray disc, the second light, etc. For the information recording medium DVD, the push-pull method can be applied to the tracking servo without using the heterodyne method with a complicated arithmetic circuit, and in this case, the DC offset can be easily corrected. is there. That is, when the push-pull method is applied, a DC offset due to a shift of the objective lens for the field of view of the optical information recording medium with respect to the disc, a disc skew, etc. occurs in the tracking error signal. Usually, a correction circuit for correcting this CD offset is provided.
On the other hand, in the configuration of the present invention, the first optical information recording medium, for example, BD, the second optical information recording medium is recorded on the DVD and / or reproduced from the above two-wavelength light receiving / emitting integrated element. Or the second wavelength light is emitted to irradiate each of the first or second optical information recording media, and at the same time, the third wavelength light of the long wavelength light from the one-wavelength light receiving / emitting integrated element. The first or second optical information recording medium is irradiated, and the return light having the third wavelength is detected in the one-wavelength light emitting / receiving integrated element. In this case, since the third wavelength light is a long wavelength light, the RF signal is not read from the first or second optical information recording medium, and the offset component is corrected by the third wavelength light. The push-pull signal that has not been made can detect the E signal and the F signal of only the offset component, and the first or second of the short wavelength can be detected by performing balance control of these E signal and F signal, that is, tracking control. The DC offset correction of the push-pull signal for obtaining the tracking error signal for the first or second optical information recording medium having the wavelength of can be performed.
As described above, according to the configuration of the present invention, the push-pull method with simplified offset correction can be applied to the detection of the tracking error signal of the first or / and second optical information recording medium. is there.

  Embodiments of an optical integrated device, an optical pickup device, and an optical information recording / reproducing device according to the present invention will be described with reference to the drawings with embodiments of the optical information recording / reproducing device according to the present invention. However, the optical integrated device, the optical pickup device, and the optical information recording / reproducing device according to the present invention are not limited to the illustrated embodiments.

FIG. 1 is a block diagram showing an example of an embodiment of an optical information recording / reproducing apparatus 10 according to the present invention.
The optical information recording / reproducing apparatus 10 can exchange and detach an optical information recording medium M having three types of formats, and rotates and drives the optical information recording medium M on the same axis. And at least an optical pickup device 2 according to the present invention.
The optical information recording medium M according to the three types of formats includes a BD, for example, a Blu-ray disc using blue laser light having a first wavelength of, for example, about 405 nm, and a second optical information recording medium. DVD using a red laser beam having a wavelength of 2, for example, about 650 nm, and a near-infrared laser beam having a third wavelength, for example, about 780 nm, which is longer than the first and second wavelengths of the third optical information recording medium It depends on the optical disc CD.

  In this example, the optical pickup device 2 applies the above-described first to third wavelength lights to be applied to the first to third optical information media of the optical information recording medium M that is exchanged and attached to the rotation driving unit 1. The optical integrated device 3 according to the present invention for taking out and receiving the return light from the optical information recording medium M, the objective lens assembly 4 and the beam splitter 20 are provided.

The optical integrated device 3 is a two-wavelength light receiving / emitting integrated element that receives two wavelengths of the first and second wavelengths, for example, 405 nm wavelength light and 650 nm wavelength light, and receives return light from the optical information recording medium M 3A, a third wavelength light, for example, a 780 nm wavelength light, and a one-wavelength light receiving / emitting integrated element 3B that receives the return light from the optical information recording medium.
On the other hand, the objective lens structure 4 having the objective lens 41 corresponding to, for example, three wavelengths common to the first, second, and third wavelength lights is disposed.
In the objective lens structure 4, the optical axis 11 at the reference position is selected on an axis perpendicular to the surface of the optical information recording medium M.
In the example shown in the drawing, the objective lens structure 4 is configured such that, for example, an objective lens 41 corresponding to three wavelengths and a liquid crystal type spherical aberration correcting element 6 are arranged on a common optical axis 11 so that aberration correction is optimal for three wavelengths. It is made into a structured.

  The first wavelength light emitted from the two-wavelength light receiving / emitting integrated element 3A and the third wavelength light emitted from the one-wavelength light receiving / emitting integrated element 3B are respectively reflected by the beam splitter 20 on the optical axis 11 described above. The second wavelength light emitted perpendicularly to the optical information recording medium M and emitted from the two-wavelength light receiving / emitting integrated element 3A is on the optical axis 11 or on the optical axis close to and parallel to the optical axis 11. Irradiation is performed perpendicular to the optical information recording medium M.

Further, on the optical path of the three-wavelength light, for example, in the objective lens structure 4, a quarter-wave plate 7 is disposed between the objective lens 41 and the spherical aberration correction element 6.
The objective lens structure 4 is controlled to move in the axial direction for focusing adjustment and to move the optical information recording medium M in the radial direction for tracking adjustment by, for example, a biaxial actuator.
A collimating lens 8A is disposed between the first and second short-wavelength two-wavelength light emitting / receiving integrated elements 3A and the beam splitter 20.

The two-wavelength light receiving and emitting integrated element 3A includes a two-wavelength light source unit 3SA having light sources 3SA1 and 3SA2 for the first and second wavelength lights in the package 5A, and a plurality of light receiving and detecting first and second wavelength lights. The semiconductor substrate 9 having the two-wavelength light receiving portion PDA formed by arranging the photodiodes and the microprism PRSA.
The microprism PRSA is disposed, for example, on the semiconductor substrate 9 having the two-wavelength light receiving unit PDA, with the vertically rising mirror surface thereof facing the light source unit 3SA.

  2A and 2B show a schematic cross-sectional view of an example of the two-wavelength light emitting / receiving integrated element 3A and a schematic plan view in a state where the package 5A is excluded. In this example, the two-wavelength light source unit 3SA of the two-wavelength light emitting / receiving integrated element 3A includes a light source 3SA1 by a first semiconductor laser unit that emits laser light having a first wavelength, for example, 405 nm, and a laser having a second wavelength, for example, 650 nm. For example, it has a one-chip configuration in which a light source 3SA2 using a second semiconductor laser that emits light is stacked.

  The two-wavelength light receiving unit PDA includes two light-receiving elements PDA11 and PDA12 that use a common servo signal for the first and second wavelength lights, for example, photodiodes, and a dedicated RF signal detection unit between them. That is, a light receiving element PD13, for example, a photodiode dedicated to high-frequency recording information detection is formed on a semiconductor substrate 9A, for example, a Si substrate, together with an integrated circuit associated with the two-wavelength light receiving / emitting integrated element.

The first wavelength light and the second wavelength light from the two-wavelength light source unit 3SA are reflected by the rising mirror surface of the microprism PRSA and emitted onto the optical axis 11 of the objective lens 41 described above. Then, the return light of the laser light from the optical information recording medium M is introduced into the light receiving unit PDA through the mirror surface of the microprism PRSA.
The light source unit 3SA and the corresponding light receiving elements PD11, PD12, PD13 are arranged in a direction along the tangential direction of the disk of the optical information recording medium M, for example. In FIG. 2B, Rc and Tc indicate the respective center positions corresponding to the radial direction and the tangential direction in the optical information recording medium M intersecting with the optical axis 11, and at the center Rc in the radial direction, along the tangential direction. Arranged.
Then, by selecting the arrangement position of each light receiving element PD11, PD12, PD13, the thickness of the microprism PRSA, the reflectance of the surface on the array side of the light receiving element and the surface facing this, etc., the return light with respect to each light receiving element The amount of received light is optimized.

  As shown in FIG. 3, each of the light receiving elements PD11 and PD12 can be composed of, for example, an eight-divided photodiode by dividing elements a to h and a four-divided photodiode by dividing i to l. The light receiving element PD13 is configured by, for example, a photodiode having a single configuration that does not depend on a divided configuration.

  In the two-wavelength light receiving / emitting integrated element 3A having this configuration, the microprism PRSA is thinned due to its optical design by forming the light receiving element PD13 dedicated to the two-wavelength light receiving section RF. It can be directly disposed on the substrate 9A without etching through a submount and etched.

In this configuration, by operating either the first wavelength light source 3SA1 or the second wavelength light source 3SA2 of the light source unit 3SA, the first wavelength, for example, 405 nm light or the second wavelength, for example, 650 nm light is emitted. Then, for example, the light beam is emitted so as to coincide with the optical axis 11 of the objective lens 41 corresponding to the three wavelengths, and the collimating lens 8A and the beam splitter 20 are moved straight, so that the spherical aberration correcting element 6, the quarter wavelength plate 7, and the objective lens 41. The optical information recording medium M is irradiated through.
Then, the return light of the irradiation light is introduced into the two-wavelength light receiving unit PDA in the two-wavelength light receiving / emitting integrated element 3A, and, as will be described later, by the calculation of the detection output signal by the PD11 and PD12, PD21 and PD22, The king error signal and the focusing error signal are derived, and the RF signal is detected by the RF dedicated PD 13 and PD 23.

4A and 4B show a schematic sectional view of another example of the two-wavelength light emitting / receiving integrated element 3A and a schematic plan view in a state where the package 5A is excluded. In this example, the light source 3SA1 by the first semiconductor laser part that emits the laser light of the first wavelength that constitutes the two-wavelength light source part 3SA of the two-wavelength light receiving and emitting integrated element 3A and the laser light of the second wavelength are emitted. This is a case where the light source 3SA2 by the second semiconductor laser unit is formed in close proximity to each other on the semiconductor substrate 9A.
In this case, the light receiving elements PD11 and PD21 for extracting the servo signal are formed for the first and second wavelength lights of the two-wavelength light receiving part PDB, respectively, and PD12 and PD22 are formed in parallel with each other. Is the case. The light receiving elements PD13 and PD23 dedicated to RF detection, that is, dedicated to high frequency recording information detection are formed between them, the light sources 3SA1 and 3SA2 are juxtaposed, and the corresponding PD11 and PD12 are juxtaposed. PD12 and PD22 are placed close to each other.

In this configuration, the light source 3SA1 having the first wavelength and the light receiving elements PD11, PD13, and PD12 corresponding to the first wavelength are radial on the optical information recording medium M that is orthogonal to the optical axis 11 described above. The light source 3SA2 of the second wavelength and the light receiving elements PD21, PD23, and PD22 are linearly arranged on one straight line in the tangential direction centered on the straight line Rc corresponding to the center of the direction. Arranged.
That is, in this case, since the wavelength is short, the first wavelength light having the most stringent optical design and high accuracy, for example, the wavelength corresponding to the BD (Blu-ray disc), is the wavelength of the microprism PRSA. The above-mentioned radial center is reflected so that it is reflected by the mirror surface and coincides with the optical axis 11 described above toward the optical information recording medium M and its return light is introduced into the corresponding light receiving elements PD11, PD13, PD12. It is desirable to arrange them on a straight line in the tangential direction at Rc.
In this case, the second wavelength light having a second wavelength, for example, a wavelength corresponding to the DVD, is reflected by the mirror surface of the microprism PRSA and coincides with the optical axis close to and parallel to the optical axis 11 described above, thereby optical information. It is arranged on a straight line in the tangential direction so as to be directed to the recording medium M and so that its return light is introduced into the corresponding light receiving elements PD21, PD23, PD22.

  Also in this case, as shown in FIG. 3, PD11 and PD21 are configured in 8 divisions, PD12 and PD22 are configured in 4 divisions, and PD13 and PD23 dedicated to RF detection have a single configuration, for example. Can do.

  On the other hand, the one-wavelength light emitting / receiving integrated element 3B generates laser light of the third wavelength in the package 5B, as shown in FIGS. 5A and 5B in schematic cross-sectional views and a schematic plan view in a state where the package 5A is excluded. It comprises a light source unit 3SB having a light source 3SB3 by a semiconductor laser, a micro prism PRSB, and a one-wavelength light receiving unit PDB for receiving and detecting a third wavelength light. In this case, the semiconductor laser is mounted via the submount 12 selected at a required height.

In the one-wavelength light receiving section PDB, light-receiving elements PDA31 and PDA32 by two photodiodes for servo signal extraction are formed on a semiconductor substrate 9B, for example, a Si substrate, together with an integrated circuit associated with the one-wavelength light receiving / emitting integrated element.
The microprism PRSB is disposed on the one-wavelength light receiving unit PDA with the rising mirror surface facing the light source unit 3SB.
In the semiconductor substrate 9B, the light source 3SA3 and the light receiving elements PD31 and PD32 are centered on the straight line Rc corresponding to the radial direction orthogonal to the optical information recording medium of the optical axis 11 described above, and the optical axis 11 of the optical information recording medium M. They are arranged on a straight line corresponding to the intersecting tangential direction.

Then, a laser beam having a third wavelength of 780 nm from the light source unit 3SA is introduced into the beam splitter 20 in a direction perpendicular to the optical axis 11 by the microprism, and is bent and matched with the optical axis 11 to thereby produce spherical aberration. The optical information recording medium M is irradiated through the correction element 6, the quarter-wave plate 7 and the objective lens 41.
The return light is introduced into the one-wavelength light receiving unit PDA in the one-wavelength light receiving / emitting integrated element 3B, and, as will be described later, the tracking error signal and the focusing error signal are derived by calculating the detection output signal by the PD31 and PD32. The RF signal is detected by the light receiving element PD33 dedicated to detecting high-frequency recording information dedicated to RF.

  As shown in FIG. 6, the light receiving elements PDB31 and PDB32 of the one-wavelength light receiving / emitting integrated element 3B can have a four-divided configuration having four-divided elements a3 to d3 and i3 to l3.

In the above-described configuration, first, a case where a CD is used as the optical information recording medium M and recording or / and reproduction with respect to the CD will be described.
In this case, the two-wavelength light emitting / receiving integrated element 3A is not operated, and the one-wavelength light receiving / emitting integrated element 3B is operated to irradiate the CD of the optical information recording medium with the laser beam having the third wavelength of 780 nm as described above. Then, the return light is received by the photodiodes PD31 and PD32 shown in FIG. For example, in reproduction, as shown in FIGS. 7A, 7B, and 7C, the reproduction signal (RFsignal) of the recorded information is obtained by the sum of the dividing elements. For example, the focus error signal (Focus Error) is obtained by the differential spot size method. For example, a tracking error signal is obtained by a normal push-pull method. In FIG. 7, symbols a <b> 3 to d <b> 3 and i <b> 3 to l <b> 3 indicate detection outputs by the divided elements a <b> 3 to d <b> 3 and i <b> 3 to l <b> 3 of the photodiodes PD <b> 31 and PD <b> 32 in FIG.

In the above-described configuration, when a DVD is used as the optical information recording medium M, a 405 nm laser light source 3SA1 of the two-wavelength light source unit 3SA, a one-wavelength light source unit 3SB, and a laser light source 3SA2 having a wavelength of 650 nm, for example. Is operated and recording or reproduction is performed.
Then, the return light detects an RF signal without any calculation by the photodiode PD13 or PD23 shown in FIG. 3 according to the configuration of FIG. 2 or FIG.
Then, as shown in FIG. 8A and FIG. 8B by the photodiodes PD11 and PD12 or PD21 and PD22, for example, a focus error signal (Focus Error) is obtained by the differential spot size method, for example, DPD (Differential Phase Detector). ) Method can be used to obtain a tracking error signal.
In FIG. 8, symbols a to d and i to l indicate detection outputs by the respective divided elements a2 to d2 and i2 to l2 of the photodiodes PD21 and PD22 of FIG.

When a BD, for example, a Blu-ray disc is used as the optical information recording medium M, the laser light source 3SA1 having the light source 405 nm of the two-wavelength light source unit 3SA of the two-wavelength light receiving / emitting integrated element 3A is operated, and the other 650 nm The light source 3SA2 is turned off, and recording or reproduction with respect to the Blu-ray disc is performed by the first wavelength light.
Also in this case, the RF signal is detected by the photodiode PD13 dedicated to high-frequency recording information detection, and the photodiodes PD11 and PD12 shown in FIG. The focus error signal can be obtained by the operation shown, that is, for example, by the operating spot size method, and the tracking error signal can be obtained by, for example, the DPD method.

As described above, in recording or / and reproduction of a BD such as a Blu-ray disc and a DVD, the tracking error signal can be detected by the DPD method described above. In the present invention, for example, the photodiode shown in FIG. The push-pull method using PD11 (PD21) or / and PD12 (PD22) can be used, and in this case, offset correction by shifting the objective lens by visual field swing in the radial direction of the optical information recording medium can be easily performed. It can be done.
That is, according to the configuration of the present invention, this offset correction is performed without using an offset correction circuit as usual, for example, with the emission of the first wavelength light or the second h long light, In operation, a 780 nm laser beam corresponding to the CD of the long wavelength third wavelength light is emitted, and irradiated to the BD or DVD of the optical information recording medium M together with the first or second wavelength. The return light is detected by the light receiving unit PDB of the one-wavelength light receiving / emitting integrated element 3B. At this time, since the third wavelength light has a long wavelength, the RF information signal of the BD or DVD is A push-pull signal can be taken out without detection. At this time, a push-pull signal that is not subjected to offset correction becomes an offset signal. That is, for example, the DC offset can be corrected by correcting the balance of the E signal by a3 + b3 + k3 + l3 and the F signal by c3 + d3 + i3 + j3 of PD31 and PD32 in FIG. 7 by tracking control.

  As described above, according to the configuration of the present invention, detection is performed by providing a light receiving element dedicated to high-frequency recording information detection separately from the light receiving unit for extracting the servo signal for the first and second light beams having the short wavelength. The amount of RF signal can be increased, and the S / N of reproduction can be improved by reducing noise.

In addition, according to the configuration of the present invention, the three-wavelength optical integrated device 3 that enables recording or / and reproduction with respect to three types of CD, DVD, and BD (Blu-ray disc), and thus the optical pickup device 2. In the optical information recording / reproducing apparatus 10, the two-wavelength light receiving / emitting integrated element 3A is integrated with respect to the BD requiring optically strict conditions in recording / reproducing and the first and second wavelength lights corresponding to the DVD corresponding thereto. However, when the optical design of the Blu-ray disc is optimized or selected close to this, conditions for comparatively good conditions are set for the DVD.
With respect to the CD, since this is the single one-wavelength light emitting / receiving integrated element 3B, it is possible to apply a technique that has been sufficiently researched and developed in the conventional CD recording / reproducing apparatus. This is advantageous in actual production.

  Further, according to the configuration of the present invention, when recording or / and reproducing for DVD and BD, it is possible to obtain a push-pull DC offset correction signal by simultaneously using CD-compatible wavelength light. .

  In addition, according to the configuration described above, since the structure is a single objective lens structure, the structure is simplified, and the positional relationship with each wavelength light, simplification of axis alignment, etc., reduction in size and weight are achieved, and mass productivity is achieved. Can be improved and the price can be reduced.

  Further, as in the above-described configuration, the beam splitter 20 is used in the pickup device and the optical information recording / reproducing device, and the third wavelength light, for example, 780 nm CD-compatible light is aligned with other light. In some cases, the optical path length for the third wavelength light can be arbitrarily selected, so that aberration correction can be reliably performed.

  Needless to say, the optical integrated device 3, the optical pickup device 2, and the optical information recording / reproducing device 10 according to the present invention are not limited to the above-described embodiments. For example, the format is based on a Blu-ray disc. An optical integrated device, an optical pickup device, and an optical information recording / reproducing device for other blue light-compatible BDs, CDs, DVDs, and the like, which are limited to short wavelength discs, can also be used.

It is a block diagram of an example of the optical information recording / reproducing apparatus by this invention. FIG. A is a schematic cross-sectional view of an example of a two-wavelength light receiving / emitting integrated element of the optical integrated device according to the present invention, and FIG. B is a schematic plan view in a state where the package is excluded. It is a pattern figure of an example of the 2 wavelength light-receiving part of an example of the 2 wavelength light receiving / emitting integrated element of the optical integrated device by this invention. FIG. A is a schematic cross-sectional view of another example of the two-wavelength light receiving / emitting integrated element of the optical integrated device according to the present invention, and FIG. B is a schematic plan view with the package removed. FIG. A is a schematic cross-sectional view of an example of a single-wavelength light receiving / emitting integrated element of the optical integrated device according to the present invention, and FIG. B is a schematic plan view in a state where the package is excluded. It is a pattern diagram of an example of the 1 wavelength light receiving part of an example of the 1 wavelength light receiving / emitting integrated element of the optical integrated device by this invention. A, B, and C are diagrams showing an example of a method for deriving and calculating a high-frequency recording information signal, a focus error signal, and a tracking error signal in one operation state of the optical information recording / reproducing apparatus according to the present invention. A and B are diagrams showing a calculation method for deriving a focus error signal and a tracking error signal in one operation state of the optical information recording / reproducing apparatus according to the present invention, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotation drive part of optical information recording medium, 2 ... Optical pick-up apparatus, 3 ... Optical integrated device, 3A ... 2 wavelength receiving / emitting integrated element, 3B ... 1 wavelength receiving / emitting integrated element, 3SA ... 2 Wavelength light source unit, 3SB: 1 wavelength light source unit, 4 ... Objective lens structure, 5A, 5B ... Package, 6 ... Aberration correction element, 7 ... 1/4 wavelength plate, 8A ... Collimator lens, 9A, 9B ... Semiconductor substrate, 12 ... Submount, 20 ... Beam splitter, 41 ... Objective lens for 3 wavelengths, PRSA, PRSB ... Micro prism, PDA ... 2 wavelength light receiving part, PDB ... 1 wavelength light Light receiving part, PD11, PD12, PDP21, PD22, PD31, PD32... Light receiving element for extracting servo signals, PD13.

Claims (14)

A two-wavelength light receiving and emitting integrated element and a one wavelength light emitting and receiving integrated element;
The two-wavelength light emitting / receiving integrated element includes a light source of a first wavelength light corresponding to the first optical information recording medium and a second light source corresponding to a second optical information recording medium having a longer wavelength than the first wavelength light. A two-wavelength light source unit having a light source of the wavelength light, a microprism, and return light of the first and second wavelength light from the first and second optical information recording media is introduced by the microprism. A two-wavelength light receiving portion detected by
The one-wavelength light receiving and emitting integrated element includes a one-wavelength light source unit for third wavelength light corresponding to a third optical information recording medium having a longer wavelength than the first and second wavelengths, and the third optical information. A one-wavelength light receiving portion that is detected by introducing the return light of the third wavelength from the recording medium,
The optical integrated circuit characterized in that the light receiving section of the two-wavelength light receiving / emitting integrated element includes a light receiving element for extracting a servo signal and a light receiving element dedicated to high frequency recording information detection separately from the light receiving element. apparatus. The first optical information recording medium is an optical disc compatible with blue laser light;
The second optical information recording medium is a DVD (Digital Versatile Disc);
2. The optical integrated device according to claim 1, wherein the third optical information recording medium is a CD (Compact Disc). The two-wavelength light source unit of the two-wavelength light receiving and emitting integrated element includes a first semiconductor laser unit that emits the laser beam having the first wavelength, and a second semiconductor laser unit that emits the laser beam having the second wavelength. Is made up of
2. The two-wavelength light receiving section includes a light receiving element for extracting a servo signal common to the first and second wavelength lights and a light receiving element dedicated for detecting the high-frequency recording information. The optical integrated device described in 1. The two-wavelength light source unit of the two-wavelength light receiving and emitting integrated element includes a first semiconductor laser unit that emits the laser beam having the first wavelength, and a second semiconductor laser unit that emits the laser beam having the second wavelength. Are in close juxtaposition,
The first and second semiconductors in which the light receiving element for taking out the servo signals for the first and second wavelength light of the two-wavelength light receiving part and the light receiving element dedicated for detecting the high-frequency recording information are juxtaposed, respectively. The optical integrated device according to claim 1, wherein the optical integrated device is arranged side by side corresponding to the laser unit. An objective lens and an optical integrated device;
The optical integrated device has a two-wavelength light receiving / emitting integrated element and a one wavelength receiving / emitting integrated element,
The two-wavelength light emitting / receiving integrated element includes a light source of a first wavelength light corresponding to the first optical information recording medium and a second light source corresponding to a second optical information recording medium having a longer wavelength than the first wavelength light. A two-wavelength light source unit having a light source of the wavelength light, a microprism, and return light of the first and second wavelength light from the first and second optical information recording media is introduced by the microprism. A two-wavelength light receiving portion detected by
The one-wavelength light receiving and emitting integrated element includes a one-wavelength light source unit for third wavelength light corresponding to a third optical information recording medium having a longer wavelength than the first and second wavelengths, and the third optical information. A one-wavelength light receiving portion that is detected by introducing the return light of the third wavelength from the recording medium,
The pick-up apparatus, wherein the light receiving portion of the two-wavelength light receiving / emitting integrated element includes a light receiving element for extracting a servo signal and a light receiving element dedicated to high-frequency recording information detection separately from the light receiving element. .   The objective lens is compatible with the three wavelengths common to the first wavelength light, the second wavelength light from the two-wavelength light receiving and emitting integrated element, and the third wavelength light from the one wavelength receiving and emitting integrated element. The pickup apparatus according to claim 5, comprising an objective lens. The first optical information recording medium is an optical disc compatible with blue laser light;
The second optical information recording medium is a DVD (Digital Versatile Disc);
6. The optical pickup device according to claim 5, wherein the third optical information recording medium is a CD (Compact Disc). The two-wavelength light source unit of the two-wavelength light receiving and emitting integrated element includes a first semiconductor laser unit that emits the laser beam having the first wavelength, and a second semiconductor laser unit that emits the laser beam having the second wavelength. Is made up of
6. The two-wavelength light receiving section has a light receiving element for extracting a servo signal common to the first and second wavelength lights and a light receiving element dedicated for detecting the high frequency recording information. The optical pickup device described in 1. The two-wavelength light source unit of the two-wavelength light receiving and emitting integrated element includes a first semiconductor laser unit that emits the laser beam having the first wavelength, and a second semiconductor laser unit that emits the laser beam having the second wavelength. Are in close juxtaposition,
The first and second semiconductors in which the light receiving element for taking out the servo signals for the first and second wavelength light of the two-wavelength light receiving part and the light receiving element dedicated for detecting the high-frequency recording information are juxtaposed, respectively. 6. The optical pickup device according to claim 5, wherein the optical pickup device is arranged in parallel to correspond to the laser unit. A first optical information recording medium, a second optical information recording medium, a third optical information recording medium, a rotation driving device that is rotationally driven by being exchanged and attached, and an optical pickup device;
The optical pickup device includes an objective lens and an optical integrated device,
The optical integrated device has a two-wavelength light receiving / emitting integrated element and a one wavelength receiving / emitting integrated element,
The two-wavelength light emitting / receiving integrated element includes a light source of a first wavelength light corresponding to the first optical information recording medium and a second light source corresponding to a second optical information recording medium having a longer wavelength than the first wavelength light. A two-wavelength light source unit having a light source of the wavelength light, a microprism, and return light of the first and second wavelength light from the first and second optical information recording media is introduced by the microprism. A two-wavelength light receiving portion detected by
The one-wavelength light emitting / receiving integrated element includes a one-wavelength light source unit for third wavelength light corresponding to a third optical information recording medium having a longer wavelength than the first and second wavelengths, a microprism, and the third prism. A one-wavelength light receiving portion that is detected by introducing the return light of the third wavelength from the optical information recording medium,
The light receiving portion of the two-wavelength light receiving and emitting integrated element comprises a light receiving element for extracting a servo signal and a light receiving element dedicated to high frequency recording information detection separately from the light receiving element,
An optical information recording / reproducing apparatus for performing recording or / and reproduction on the respective optical information recording media.   The objective lens is compatible with the three wavelengths common to the first wavelength light, the second wavelength light from the two-wavelength light receiving and emitting integrated element, and the third wavelength light from the one wavelength receiving and emitting integrated element. The optical information recording / reproducing apparatus according to claim 10, comprising an objective lens. The first optical information recording medium is an optical disc compatible with blue laser light;
The second optical information recording medium is a DVD (Digital Versatile Disc);
11. The optical information recording / reproducing apparatus according to claim 10, wherein the third optical information recording medium is a CD (Compact Disc). The two-wavelength light source unit of the two-wavelength light receiving and emitting integrated element includes a first semiconductor laser unit that emits the laser beam having the first wavelength, and a second semiconductor laser unit that emits the laser beam having the second wavelength. Is made up of
11. The two-wavelength light receiving section has a light receiving element for extracting a servo signal common to the first and second wavelength lights and a light receiving element dedicated for detecting the high frequency recording information. 2. An optical information recording / reproducing apparatus according to 1. The two-wavelength light source unit of the two-wavelength light receiving and emitting integrated element includes a first semiconductor laser unit that emits the laser beam having the first wavelength, and a second semiconductor laser unit that emits the laser beam having the second wavelength. Are in close juxtaposition,
The first and second semiconductors in which the light receiving element for taking out the servo signals for the first and second wavelength light of the two-wavelength light receiving part and the light receiving element dedicated for detecting the high-frequency recording information are juxtaposed, respectively. The optical information recording / reproducing apparatus according to claim 10, wherein the optical information recording / reproducing apparatus is arranged side by side corresponding to the laser unit.

Images