JP2001167465A - Optical head and optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make plural divided light receiving parts of a light receiving means properly receivable return light of respective laser beams emitted from these light sources of a light emitting means wherein respective light sources emitting the laser beams corresponding to different kinds of plural optical recording media are housed within the same package. SOLUTION: This device is provided with a light emitting means wherein the relative positional relation between a first light source and a second light source is set so that the line connecting the spot position of a first laser beam irradiating the optical recording medium to the spot position of a second laser beam irradiating the optical recording medium crosses so as to be nearly orthogonal to the recording track of the optical recording medium and the light receiving means having plural light receiving parts divided by a dividing line nearly parallel to a projected line when the line connecting the spot position of the first laser beam irradiating the optical recording medium to the spot position of the second laser beam irradiating the optical recording medium is projected on the light receiving means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head corresponding to a plurality of different types of optical recording media, and to record and / or reproduce signals on a plurality of different types of optical disks using such an optical head. The present invention relates to an optical disk device.

[0002]

2. Description of the Related Art Conventionally, a CD (Compact) has been used as an optical recording medium.
Disc) or a read-only optical disc called CD-R (C
Ompact Disc-Recordable) has been put into practical use. These optical discs have been widely used because of their excellent mass productivity, low production cost, and relatively stable reproduction or recording of information.

Incidentally, in such an optical disk, the recording capacity has been actively increased in recent years. In such a situation, the recording capacity has been dramatically increased while keeping the outer diameter dimension the same as that of a CD, and a DVD capable of storing data for one movie with image quality comparable to that of a current television broadcast.
(Digital Versatile Disc / Digital Video Disc) has been developed and put to practical use. In order to increase the recording density and increase the recording capacity, this DVD is
Recording and reproduction of information are performed using a laser having a shorter wavelength than a laser used for the above.

In an optical disk apparatus using an optical disk as a recording medium, information can be recorded on and reproduced from the DVD, and a CD or CD-R
In addition, an optical head having a so-called compatible optical head capable of recording and reproducing information has been developed.

[0005]

In an optical head capable of supporting both a CD, a CD-R, and a DVD, a CD or a CD must be used in order to reduce the size of the head and the manufacturing cost. It is desirable that the optical system for -R and the optical system for DVD are made as common as possible.

To meet such demands, CDs and CDs
An optical head provided with a so-called two-wavelength semiconductor laser that selectively emits both laser light corresponding to -R and laser light corresponding to DVD has been developed.

In the two-wavelength semiconductor laser, a light source that emits laser light corresponding to a CD or CD-R and a light source that emits laser light corresponding to a DVD are arranged in close proximity to each other, and are housed in the same package. Configuration. Further, in this optical head, in order to enable detection of a tracking error signal and a focus error signal corresponding to both a CD, a CD-R, and a DVD, the return of each laser beam reflected and returned from these optical disks is performed. A light receiving element for receiving light is provided. The light receiving element has a plurality of light receiving sections divided so that return light of each laser light reflected and returned from the optical disk is irradiated to a predetermined position.

However, in an optical head having such a two-wavelength semiconductor laser, when the distance between light sources deviates from a predetermined design value, return light of each laser beam emitted from these light sources is transmitted to the light receiving element. In some cases, the light receiving unit divided into a plurality of parts cannot properly receive light.

For this reason, in this optical head, a CD or C
The focus error signal and the tracking error signal corresponding to both the D-R and the DVD cannot be detected. When this optical head is mounted on the optical disk device,
There has been a problem that focusing control for focusing the objective lens on the signal recording surface of the optical disk and tracking control for causing the spot of the laser beam to follow a recording track on the signal recording surface of the optical disk cannot be properly performed.

In view of the foregoing, the present invention has been proposed in view of the above-mentioned circumstances, and includes a light source in which the light sources for emitting laser beams corresponding to a plurality of different types of optical recording media are housed in the same package. An optical head of the emitting unit, which enables the return light of each laser beam emitted from these light sources to be appropriately received by a plurality of divided light receiving units of the light receiving unit, and a type using such an optical head. It is an object of the present invention to provide an optical disk device capable of appropriately performing recording and / or reproduction of signals on a plurality of optical disks having different types.

[0011]

An optical head according to the present invention that achieves this object is an optical head corresponding to a plurality of different types of optical recording media, and a first light source for emitting a first laser beam. And a second laser having a different wavelength from the first laser light
A light emitting means in which a second light source for emitting the laser light is housed in the same package; and a light collecting means for focusing the laser light emitted from the light emitting means on a signal recording surface of the optical recording medium. A beam splitter that separates the laser light emitted from the light emitting means into a laser light applied to the optical recording medium and a laser light reflected from the optical recording medium and returned, and reflected and returned from the optical recording medium. Light receiving means for receiving incoming laser light. A straight line connecting the spot position of the first laser light irradiated on the optical recording medium and the spot position of the second laser light irradiated on the optical recording medium is substantially aligned with the recording track of the optical recording medium. The relative positional relationship between the first light source and the second light source is set to be orthogonal. Further, the light receiving means projects a straight line connecting the spot position of the first laser light irradiated on the optical recording medium and the spot position of the second laser light irradiated on the optical recording medium onto the light receiving means. Sometimes, a plurality of light receiving sections divided by a dividing line substantially parallel to the projected straight line is provided.

As described above, in the optical head according to the present invention, even if an error occurs in the distance between the first light source and the second light source of the light emitting means, the first light emitted from the first light source can be obtained. The return light from the optical recording medium irradiated with the laser light and the return light from the optical recording medium irradiated with the second laser light emitted from the second light source are irradiated on the optical recording medium. When a straight line connecting the spot position of the first laser light and the spot position of the second laser light is projected on the light receiving means, a plurality of light receiving sections divided by a dividing line substantially parallel to the projected straight line Can be appropriately irradiated to the divided portions. Thus, the optical head can appropriately detect a light receiving signal for generating a focus error signal and a tracking error signal corresponding to a plurality of different types of optical recording media.

According to another aspect of the present invention, there is provided an optical disc apparatus for recording and / or reproducing signals on and from a plurality of different types of optical discs. An optical head corresponding to a plurality of optical disks different from each other, and signal processing means for generating a reproduction signal and a control signal based on a signal detected by the optical head.
The optical head is a light source in which a first light source that emits a first laser light and a second light source that emits a second laser light having a different wavelength from the first laser light are housed in the same package. An emitting unit, a condensing unit for condensing a laser beam emitted from the light emitting unit on a signal recording surface of the optical disc, and a laser beam emitted from the light emitting unit and reflected from the optical disc and the laser beam applied to the optical disc. And a beam splitter that separates it into laser light that returns
Light receiving means for receiving the laser light reflected back from the optical disk. The light emitting means includes: a spot position of the first laser beam irradiated on the optical disc;
The relative positional relationship between the first light source and the second light source is set such that a straight line connecting the spot position of the second laser beam irradiated on the optical disc is substantially orthogonal to the recording track of the optical disc. I have. Further, the light receiving means, when projecting a straight line connecting the spot position of the first laser light irradiating the optical disc and the spot position of the second laser light irradiating the optical disc onto the light receiving means, It is characterized by having a plurality of light receiving sections divided by a dividing line substantially parallel to the projected straight line.

As described above, in the optical disk apparatus according to the present invention, even if an error occurs in the distance between the first light source and the second light source of the light emitting means in the optical head, the light is emitted from the first light source. Return light from the optical disc irradiated with the first laser light and return light from the optical disc irradiated with the second laser light emitted from the second light source,
When a straight line connecting the spot position of the first laser beam and the spot position of the second laser beam irradiated on the optical disc is projected on the light receiving means, the straight line is divided by a dividing line substantially parallel to the projected straight line. It is possible to appropriately irradiate the divided portions of the plurality of light receiving units. Thus, in this optical disc device, the optical head appropriately detects a light receiving signal for generating a focus error signal and a tracking error signal corresponding to a plurality of different types of optical recording media. And / or reproduction of a signal with respect to the optical disc can be appropriately performed.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 and 2 show an example of the configuration of an optical head to which the present invention is applied.

The optical head 1 has a thickness of, for example, 1.2 m.
CD-R (Compact Dis
c-Recordable) and a DVD (Digital Versatile Disposable) consisting of two 0.6 mm thick disc substrates bonded together.
c / Digital Video Disc), which is an optical head corresponding to two types of optical discs 2 for recording and reproducing information by using laser beams having different wavelengths. FIG.
The optical head 1 is connected to the signal recording surface 2a of the optical disk 2.
FIG. 2 is a schematic plan view seen from a direction substantially perpendicular to FIG.
The optical head 1 is connected to the signal recording surface 2a of the optical disk 2.
FIG. 2 is a schematic side view as viewed from a direction substantially parallel to.

The optical head 1 has a two-wavelength semiconductor laser 3 for emitting two different types of laser light.
And a grating 4 that divides the laser light emitted from the two-wavelength semiconductor laser 3 into a plurality of beams, a beam splitter 5 disposed in an optical path of the laser light that has passed through the grating 4, and transmitted through the beam splitter 5. A collimator lens 6 that collimates the laser light, a quarter-wave plate 7 disposed in the optical path of the laser light that has been collimated by the collimator lens 6, and a laser that has passed through the quarter-wave plate 7 Light is applied to the signal recording surface 2 of the optical disc 2
a, a Foucault prism 9 through which return light reflected from the signal recording surface 2a of the optical disk 2 is transmitted, and a light receiving element 10 which receives laser light transmitted through the Foucault prism 9 And

The optical head 1 is provided with a mirror 11 in an optical path between the beam splitter 5 and the collimator lens 6. As a result, the laser beam transmitted through the beam splitter 5 is bent by being reflected by the mirror 11, and is irradiated substantially perpendicularly to the signal recording surface 2a of the optical disk 2 located above the optical head 1. It will be.

The two-wavelength semiconductor laser 3 is a light-emitting element utilizing recombination light emission of a semiconductor, and has a thickness of, for example, 1.2 mm.
A laser beam of about 780 nm (hereinafter, referred to as a first laser beam), which is an optimal wavelength for a CD-R comprising a single disk substrate, and two disk substrates having a thickness of 0.6 mm are attached. A laser beam having a wavelength of about 650 nm (hereinafter, referred to as a second laser beam), which is an optimal wavelength corresponding to the combined DVD, is selectively emitted. Specifically, as shown in FIG. 3, when the optical disc 2 is a CD-R, the two-wavelength semiconductor laser 3 has a first light emitting point A that emits a laser beam corresponding to the optical disc 2. A laser chip 12 and a second laser chip 13 having a second light emitting point B for emitting a laser beam corresponding to the optical disk 2 when the optical disk 2 is a DVD. Then, the two-wavelength semiconductor laser 3 is connected to the first laser chip 12 and the second laser chip 12.
The laser chip 13 is arranged on a base 14, and the base 14 is housed inside a package member 15. In the two-wavelength semiconductor laser 3,
The first laser chip 12 as one laser chip
And the second laser chip 13 may be integrally formed.

In this two-wavelength semiconductor laser 3, the first
The laser chip 12 and the second laser chip 13 are arranged at positions close to each other on the base 14, and the distance t between the first light emitting point A and the second light emitting point B is 80 μm or more. It is about 200 μm. Therefore,
The first laser light and the second laser light emitted from the two-wavelength semiconductor laser 3 irradiate the optical disc 2 through substantially the same optical path.

The first laser chip 12 and the second laser chip 13 are arranged on a base 14 in a plane substantially parallel to the signal recording surface 2a of the optical disk 2. Therefore, the first laser light and the second laser light are emitted from the two-wavelength semiconductor laser 3 in a direction substantially parallel to the signal recording surface 2a of the optical disk 2.

The grating 4 is, as shown in FIG.
The diffraction grating is a diffraction grating that diffracts the laser light emitted from the two-wavelength semiconductor laser 3 and divides the laser light into a plurality of light beams including three light beams of zero-order light and ± first-order light. Then, the laser light split by the grating 4 enters the beam splitter 5. It should be noted that, of the laser beams split by the grating 4, light beams other than the zero-order light and the ± first-order light are omitted in the following description.

The beam splitter 5 reflects the laser light emitted from the two-wavelength semiconductor laser 3 and guides it to the optical disk 2, and transmits the return light reflected and returned from the optical disk 2 and guides it to the light receiving element 10. . And
The divergent laser light reflected by the beam splitter 5 is collimated by a collimator lens 6 and passes through a quarter-wave plate 7, as shown in FIG.

When the laser light emitted from the two-wavelength semiconductor laser 3 has polarization, the beam splitter 5 uses a polarization beam splitter to return light returning from the optical disk 2 by two wavelengths. The return to the semiconductor laser 3 can be prevented.

The quarter-wave plate 7 gives a phase difference of π / 2 to the passing laser light. The laser light that has passed through the 波長 wavelength plate becomes circularly polarized when irradiating the optical disc, and becomes linearly polarized when reflected and returned from the optical disc. Then, the laser light that has passed through the 波長 wavelength plate is focused on the signal recording surface 2 a of the optical disk 2 by the objective lens 8.

The objective lens 8 is movably supported by a biaxial actuator (not shown). The objective lens 8 is moved by a biaxial actuator on the basis of a tracking error signal and a focus error signal generated by return light from the optical disk 2 received by the light receiving element 10 described later, thereby moving the optical disk. 2 and the optical disk 2
Is moved in two radial directions. The objective lens 8 focuses the laser light emitted from the two-wavelength semiconductor laser 3 so that the laser light is always focused on the signal recording surface 2a of the optical disk 2, and also focuses the focused laser light. The optical disk 2 is made to follow a recording track formed on the signal recording surface 2a of the optical disk 2.

Here, the laser light focused on the signal recording surface 2a of the optical disk 2 is applied to the first laser chip 12
Position A1 of the first laser beam emitted from the
A straight line (a straight line indicated by a broken line in FIG. 1) connecting the spot position B1 of the second laser light emitted from the second laser chip 13 to the signal recording surface 2a of the optical disc 2
Irradiation is performed so as to be substantially perpendicular to the upper recording track, specifically, at an angle in the range of 90 ° ± 10 °. That is, in the two-wavelength semiconductor laser 3, a straight line connecting the spot position A1 of the first laser beam and the spot position B1 of the second laser beam focused on the signal recording surface 2a of the optical disk 2 is formed by the optical disk. The first laser chip 12 and the second laser chip 12 are arranged at an angle of 90 ° ± 10 ° with respect to the recording track on the signal recording surface 2a.
And a laser chip 13 are arranged on a base 14.

In the two-wavelength semiconductor laser 3, the direction in which the light emitting point A of the first laser chip 12 and the light emitting point B of the second laser chip 13 are aligned as shown in FIG. The direction is substantially perpendicular to a straight line connecting the light spot position A1 and the second laser light spot position B1.

In the following description, the optical disk 2
The spot position A1 of the first laser beam and the spot position B1 of the second laser beam focused on the signal recording surface 2a of FIG.
Is indicated by an arrow X, and the direction of a recording track on the signal recording surface 2a of the optical disc 2 is indicated by an arrow Y.

The laser light focused on the signal recording surface 2a of the optical disk 2 is reflected by the signal recording surface 2a and passes through the objective lens 8 to become parallel light. The return light reflected from the optical disk 2 and returned is 1
The light passes through the collimator lens 6 via the 波長 wavelength plate 7 to be converged light, and passes through the beam splitter 5. Then, the return light transmitted through the beam splitter 5 is
The light enters the Foucault prism 9.

As shown in FIG. 1, the Foucault prism 9 detects the focus error signal by the Foucault method, so that the return light reflected from the optical disc 2 and returned is further divided into the 0th order by the grating 4 described above. The light is divided into four in a direction substantially perpendicular to the direction of division of the light and the ± first-order light. In other words, the returning light reflected and returned from the optical disc 2 passes through the Foucault prism 9 and thereby the spot position A1 of the first laser light focused on the signal recording surface 2a of the optical disc 2 described above. The light beam is divided into four portions substantially perpendicular to the direction X of the straight line connecting the spot position B1 of the second laser beam. Then, the return light split by the Foucault prism 9 enters the light receiving element 10.

As shown in FIGS. 4 and 5, the light receiving element 10 returns the first laser beam reflected by the signal recording surface 2a of the optical disc 2 (CD-R) and the optical disc 2
A light receiving unit 16 for receiving return light of the second laser light reflected on the signal recording surface 2a of the (DVD);
A voltage conversion circuit for converting the current from 6 into a voltage,
These are configured as an integrated element. FIG. 5 is an enlarged plan view of a main part of the light receiving section 16 of the light receiving element 10 shown in FIG.

In the light receiving element 10, the light receiving section 16
Is a light receiving unit C that receives the + 1st-order light, which is a sub-beam, of the 0th-order light and ± 1st-order light split by the grating 4, and four light-receiving units that receive the 0th-order light, which is the main beam. D, E, F, and G, and a light-receiving unit H that receives −1-order light that is a sub-beam. These six light receiving sections C, D, E, F, G, and H correspond to the first laser light spot position A1 and the second laser light spot focused on the signal recording surface 2a of the optical disk 2 described above. The light receiving portions G and H are arranged along a direction corresponding to a direction X of a straight line connecting the position B1, and a pair of light receiving portions G and H are arranged so as to sandwich the four light receiving portions D, E, F and G. Have been.

Further, 4 which receives the 0-order light which is the main beam.
The two light receiving portions D, E, F, and G are straight lines connecting the spot position A1 of the first laser beam and the spot position B1 of the second laser beam focused on the signal recording surface 2a of the optical disk 2 described above. Are projected on the light receiving unit 16, the light receiving units D1 and D2, the light receiving units E1 and E2, and the light receiving units F1 and F2, which are divided by a dividing line ZZ 'substantially parallel to the projected straight line.
It has light receiving sections G1 and G2. In other words, the four light receiving units D, E, F, and G determine the spot position A1 of the first laser light and the spot position B1 of the second laser light emitted from the second laser chip 13. Each is divided into two in the direction corresponding to the direction X of the connecting straight line.

The light receiving element 10 is connected to the optical disk 2 (CD-
The return light of the first laser light reflected by the signal recording surface 2a of R) is received by the light receiving units C and H, and a light receiving signal for generating the tracking error signal TR1 by the three-beam method is detected. The return light of the first laser light reflected by the signal recording surface 2a of the optical disk 2 (CD-R) is received by the light receiving units D, E, F, and G, and the reproduction signal RF1 is received.
And a light receiving signal for generating a focus error signal FE1 by the Foucault method.

More specifically, the light receiving sections C and D of the light receiving element 10
1, D2, E1, E2, F1, F2, G1, G2, H, and SC1, SD1, SD2, SE1, SE2, and SF, respectively.
1, SF2, SG1, SG2, and SH1, the reproduction signal RF1, the focus error signal FE1, and the tracking error signal TR1 are respectively obtained by the following arithmetic expressions.

RF1 = SD1 + SD2 + SE1 + SE2
+ SF1 + SF2 + SG1 + SG2FE1 = (SD1 +
SE1 + SF2 + SG2)-(SD2 + SE2 + SF1
+ SG1) TR1 = SC1-SH1 The light receiving element 10 receives the return light of the second laser light reflected on the signal recording surface 2a of the optical disk 2 (DVD) by the light receiving units D, E, F, and G. , DPD method (Differe
The light receiving signal for generating the tracking error signal by the ntial phase detection) and the light receiving signal for generating the focus error signal by the Foucault method are detected.

Specifically, the light receiving sections C and D of the light receiving element 10
The light receiving signals based on the second laser light received by 1, D2, E1, E2, F1, F2, G1, G2, H are SC1 ', SD1', SD2 ', SE1', SE, respectively.
2 ', SF1', SF2 ', SG1', SG2 ', SH
Assuming 1 ′, the reproduction signal RF2, the focus error signal FE2, and the tracking error signal TR2 are respectively obtained by the following arithmetic expressions.

RF2 = SD1 '+ SD2' + SE1 '+
SE2 '+ SF1' + SF2 '+ SG1' + SG2 'FE2 = (SD1' + SE1 '+ SF2' + SG2 ')
− (SD2 ′ + SE2 ′ + SF1 ′ + SG1 ′) TR2 = (SD1 + SE1 + SF2 + SG2) − (SD
2 + SE2 + SF1 + SG1) Here, in the optical head 1, the optical disk 2 (CD-R)
The return light of the first laser light reflected on the signal recording surface 2a of the optical disk 2 and the return light of the second laser light reflected on the signal recording surface 2a of the optical disk 2 (DVD) are main beams. In the four light receiving portions D, E, F, and G for receiving the zero-order light, the spot position A1 of the first laser light focused on the signal recording surface 2a of the optical disk 2 and the signal recording surface 2a When a straight line connecting the spot position B1 of the second laser light condensed thereon is projected on the light receiving unit 16, the light received by the split line ZZ 'substantially parallel to the projected straight line Adjustments are made so that the light is emitted to the portions D1 and D2, the light receiving portions E1 and E2, the light receiving portions F1 and F2, and the divided portions of the light receiving portions G1 and G2.

In this case, in the two-wavelength semiconductor laser 3, the first light emitting point A of the first laser chip 12 for emitting the first laser light shown in FIG. 3 and the second light emitting point A for emitting the second laser light An error occurs in the interval t between the laser chip and the second light emitting point B, and the four light receiving units D, E, and
Spot position A of the first laser beam applied to F and G
2 and the first laser light spot focused on the signal recording surface 2a of the optical disk 2 even if the distance t 'between the second laser light spot position B2 and the second laser light spot position B2 deviates from a predetermined design value. When a straight line connecting the position A1 and the spot position B1 of the second laser beam is projected on the light receiving unit 16, the light receiving unit D1, which is divided by a dividing line ZZ 'substantially parallel to the projected straight line D2, the light receiving sections E1 and E2, the light receiving sections F1 and F2, and the divided portions of the light receiving sections G1 and G2 can be appropriately irradiated.

That is, in the optical head 1, the four light receiving portions D, E, F, and G are arranged so that the first laser beam spot position A 1 focused on the signal recording surface 2 a of the optical disk 2 and the light receiving portions D, E, F, G The laser light is divided into two in a direction corresponding to a direction X of a straight line connecting the two laser light spot positions B1.

For this reason, in the optical head 1, the first spot position A2 of the first laser light and the second spot of the second laser light applied to the four light receiving portions D, E, F, and G are provided. Even if the distance t 'from the position B2 deviates from the predetermined design value, the first spot position A2 and the second spot position B2 are not condensed on the signal recording surface 2a of the optical disc 2 by the first spot position. Of the laser beam spot position A1 and the second
Direction X of the straight line connecting the laser beam spot position B1
Will be shifted along.

Thus, in the optical head 1, the return light from the optical disk 2 irradiated with the first laser light emitted from the first laser chip 12 of the two-wavelength semiconductor laser 3, and the second laser chip The second emitted from
The return light from the optical disk 2 irradiated with the laser light is received by the light receiving portions D1, D2 and the light receiving portions E1, E of the light receiving element 10.
2. It is possible to appropriately irradiate the divided portions of the light receiving units F1 and F2 and the light receiving units G1 and G2.

Therefore, in this optical head 1, the CD
-A light receiving signal for generating a focus error signal and a tracking error signal corresponding to both the optical disc 2 of both R and DVD can be appropriately detected, and when mounted on an optical disc device to be described later, focusing control and Tracking control can be appropriately performed.

In the optical head 1, as described above, the spot position A 1 of the first laser beam emitted from the first laser chip 12 and the second laser beam emitted from the second laser chip 13 A straight line connecting the spot position B1 of the laser beam (a straight line indicated by a broken line in FIG. 1) has an angle of 90 ° ± 10 ° with respect to a recording track on the signal recording surface 2a of the optical disc 2. , A relative positional relationship between the first laser chip 12 and the second laser chip 13 is set.

In this case, a tolerance of about ± 10 ° with respect to the orthogonal direction of the recording track affects the detection of a light receiving signal for generating a reproduction signal, a focus error signal, and a tracking error signal in the light receiving element 10. Never.

The return light of the first laser light and the second light
Although the description has been given of the example in which the return light of the laser light is received and the focus error signals FE1 and FE2 are generated by the Foucault method, the optical head 1 to which the present invention is applied is limited to the above example. Instead, for example, a light receiving signal for generating the focus error signals FE1 and FE2 may be detected by a knife edge method, a differential concentric circle method, or the like.

In this case, the four light receiving portions C, D, F, and G of the light receiving element 10 are located at the spot position A 1 of the first laser light emitted from the first laser chip 12 and the second laser chip 13. When a straight line connecting the spot position B1 of the second laser light emitted from the laser beam is projected onto the light receiving section 16, a dividing line ZZ 'substantially parallel to the projected straight line
Receiving units D1, D2 and E1, E divided by
2. It can be composed of light receiving units F1, F2 and light receiving units G1, G2.

The four light receiving portions C, D, F, and G divided only by these dividing lines ZZ 'are used for the first laser beam irradiated on the four light receiving portions D, E, F, and G. In order to position the light spot position A2 and the second laser light spot position B2, these light receiving portions D, E, F, and G are divided by dividing lines orthogonal to the dividing line ZZ '. It may be configured to be divided into four.

The optical head 1 configured as above is
As shown in FIG. 7, a CD-R (Compact Disc-Reco
rdable) and a DVD (Digital Versatile Disc / Dig) consisting of two 0.6 mm thick disc substrates bonded together.
It is mounted on an optical disc device 20 corresponding to two types of optical discs 2 such as an ital Video Disc,
Recording and / or reproduction of information is performed using the laser light and the second laser light.

This optical disk device 20 is used for the optical disk 2
A spindle motor 21 for rotating the optical disk 2, and irradiating a laser beam onto the signal recording surface 2 a of the optical disk 2 mounted on the spindle motor 21,
Optical head 1 for detecting return light from the optical head 1, a signal processing circuit 22 for generating a reproduction signal and a control signal based on a light receiving signal detected by the optical head 1, and a control from the signal processing circuit 22 A focus / track servo mechanism 23 for performing focusing control and tracking control based on a signal;
And a spindle motor 21, a focus / track servo mechanism 23 and an access mechanism 2 based on a signal generated by a signal processing circuit 22 for moving the optical disc 2 to a predetermined recording track in the radial direction of the optical disc 2.
And a system controller 25 for controlling the control unit 4.

The spindle motor 21 is driven and controlled by the system controller 25, and rotates the optical disk 2 at a predetermined speed.

The optical head 1 has a signal recording surface 2 of an optical disk 2 that is rotated by driving a spindle motor 21.
A laser beam is irradiated onto the signal a, and return light reflected on the signal recording surface 2a of the optical disk 2 is detected and output to the signal processing circuit 22. At this time, the optical head 1 selectively emits the above-described first laser light and second laser light depending on the type of the optical disc 2 that is rotated.

The signal processing circuit 22 demodulates a reproduction signal and a control signal obtained based on the light receiving signal detected by the optical head 1 in a signal demodulation section and corrects an error in an error correction section.

The reproduced signal demodulated and error-corrected by the signal processing circuit 22 is sent to an external computer 27 or the like via an interface 26 if the signal is for data storage of a computer. If the reproduced signal is an audio / visual signal, the D / A, A / D converter 2
The digital-to-analog conversion is performed by the D / A conversion unit 8 and is transmitted to the audio device 29.

The various control signals demodulated by the signal processing circuit 5 are output to the system controller 25. The system controller 25 drives the focus / track servo mechanism 23 based on the focus error signal and the tracking error signal from the control signals.
Under the control of the system controller 25, the focus / track servo mechanism 23 moves the two-axis actuator of the optical head 1 in two directions, ie, the direction in which the optical head 1 approaches and separates from the optical disk 2 and the radial direction of the optical disk 2, to perform focusing control and Perform tracking control.

The access mechanism 24 moves the optical head 1 in the radial direction of the optical disk 2 based on a signal supplied from the system controller 25, and moves the optical head 1 to a position on a predetermined recording track of the optical disk 2. Let it.

The optical disk device 2 configured as described above
At 0, by mounting the optical head 1 to which the present invention is applied, it is possible to appropriately perform focusing control and tracking control, and to appropriately perform signal recording and / or reproduction with respect to the optical disc 2.

[0060]

As described above in detail, according to the present invention, light is emitted from the first light source even if an error occurs in the distance between the first light source and the second light source of the light emitting means. The optical recording medium is irradiated with the return light from the optical recording medium irradiated with the laser light and the return light from the optical recording medium irradiated with the second laser light emitted from the second light source. First
When a straight line connecting the spot position of the laser light and the spot position of the second laser light is projected onto the light receiving means, a plurality of light receiving portions divided by a dividing line substantially parallel to the projected straight line are obtained. The divided portions can be appropriately irradiated.

Therefore, in the optical head to which the present invention is applied, a light receiving signal for generating a focus error signal and a tracking error signal corresponding to a plurality of different types of optical recording media such as a CD-R and a DVD is appropriately detected. can do.

Further, in the optical disk device to which the present invention is applied, by providing such an optical head, it is possible to appropriately record and / or reproduce signals on a plurality of different types of optical disks.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing one configuration example of an optical head to which the present invention is applied.

FIG. 2 is a schematic side view showing a configuration of the optical head.

FIG. 3 is a perspective plan view showing a configuration example of a two-wavelength semiconductor element constituting the optical head.

FIG. 4 is a schematic plan view showing a configuration example of a light receiving element constituting the optical head.

FIG. 5 is an enlarged plan view of a main part of a light receiving unit of the light receiving element.

FIG. 6 is an enlarged plan view of a main part showing four light receiving units D, E, F, and G;

FIG. 7 is a block diagram showing a configuration of an optical disk device on which the optical head is mounted.

[Explanation of symbols]

1 optical head, 2 optical disk, 2a signal recording surface,
3 2 wavelength semiconductor laser, 4 grating, 5 beam splitter, 6 collimator lens, 71/4 wavelength plate, 8 objective lens, 9 Foucault prism, 10 light receiving element, 11 mirror, 12 first laser chip, 1
3 Second laser chip, 14 bases, 15 package member, 16 light receiving section, 20 optical disk device

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01S 5/022 H01S 5/022 5/40 5/40 F-term (Reference) 5D118 AA26 BA01 BB02 BF02 BF03 CD02 CD03 CD08 CF02 CF03 CF08 CG04 CG07 CG09 CG24 CG26 CG33 CG36 DA17 5D119 AA04 AA41 BA01 DA01 DA05 EA02 EA03 EB14 EC40 EC41 EC46 EC47 FA05 FA08 JA22 KA02 KA16 KA17 KA20 LB04 LB09 5F073 AB06 BA05 EA29 FA23

Claims (20)

[Claims] 1. An optical head corresponding to a plurality of different types of optical recording media, comprising: a first light source for emitting a first laser light; and a second laser having a different wavelength from the first laser light. A light emitting unit in which a second light source for emitting light is housed in the same package; and a condensing unit for condensing laser light emitted from the light emitting unit on a signal recording surface of the optical recording medium. A beam splitter that separates a laser beam emitted from the light emitting unit into a laser beam applied to the optical recording medium and a laser beam reflected from the optical recording medium and returned; Light receiving means for receiving laser light reflected back from the optical recording medium, wherein the light emitting means irradiates the optical recording medium with a spot position of the first laser light applied to the optical recording medium. On The relative positional relationship between the first light source and the second light source is set such that a straight line connecting the spot position of the second laser light is substantially orthogonal to the recording track of the optical recording medium. And the light receiving means is configured to irradiate the first optical recording medium with the first light.
When a straight line connecting the spot position of the laser light and the spot position of the second laser light applied to the optical recording medium is projected on the light receiving means, a division substantially parallel to the projected straight line is obtained. An optical head having a plurality of light receiving sections divided by lines. 2. The light emitting means, wherein the distance between the first light source and the second light source is 80 μm to 200 μm.
2. The optical head according to claim 1, wherein 3. The optical head according to claim 1, further comprising a quarter-wave plate between said light emitting means and said optical recording medium. 4. An optical head according to claim 1, further comprising a Foucault prism between said beam splitter and said light receiving means. 5. The light receiving means includes: a plurality of light receiving units divided only by a dividing line substantially parallel to the projected straight line;
2. The optical head according to claim 1, wherein a light receiving signal for generating a focus error signal is detected. 6. The light receiving means includes: a plurality of light receiving units divided only by dividing lines substantially parallel to the projected straight line;
2. The optical head according to claim 1, wherein a light receiving signal for generating a reproduction signal from the optical recording medium is detected. 7. A diffraction grating is provided between the light emitting means and the beam splitter for dividing laser light emitted from the light emitting means into a plurality of light beams including a main beam and a sub beam. The light receiving means has a pair of light receiving sections on both sides in a direction substantially perpendicular to the projected straight line of the plurality of light receiving sections, and the pair of light receiving sections is formed of a plurality of light beams divided by the diffraction grating. 2. The optical head according to claim 1, wherein a light receiving signal for generating a tracking error signal is detected by receiving the sub beam. 8. The light emitting means is configured to form a straight line connecting the spot of the first laser light applied to the optical recording medium and the spot of the second laser light applied to the optical recording medium. The relative positional relationship between the first light source and the second light source is set so as to be at an angle of 90 ° ± 10 ° with respect to a recording track of the optical recording medium. The optical head according to claim 1, wherein 9. A laser beam emitted from the light emitting means in a direction substantially parallel to a signal recording surface of the optical recording medium is directed between the beam splitter and the focusing means toward the focusing means. The optical head according to claim 1, further comprising a deflecting member for deflecting the light. 10. The light emitting means, wherein the first light source and the second light source are arranged in a plane substantially parallel to a signal recording surface of the optical recording medium. The optical head according to claim 1. 11. An optical disc apparatus for recording and / or reproducing signals on and from a plurality of different types of optical discs, comprising: a spindle motor for driving the optical disc to rotate; and an optical head corresponding to the plurality of different kinds of optical discs. Signal processing means for generating a reproduction signal and a control signal based on a signal detected by the optical head, wherein the optical head comprises: a first light source for emitting a first laser beam; A light emitting means in which a second light source for emitting a second laser light having a different wavelength from that of the laser light is housed in the same package; and the laser light emitted from the light emitting means is transmitted to a signal recording surface of the optical disk. A condensing means for converging the laser light on the optical disc, and a laser light emitted from the light emitting means, A beam splitter that separates the laser light reflected from the disk back into a laser beam; and a light receiving unit that receives the laser light reflected back from the optical disk. The light emitting unit irradiates the optical disk. The first laser light is irradiated on the optical disc by arranging the first laser light so that a straight line connecting the spot position of the second laser light and the second laser light is substantially orthogonal to a recording track of the optical disc. The relative positional relationship between the light source and the second light source is set, and the light receiving unit is configured to irradiate the first optical disc onto the first optical disc.
When a straight line connecting the spot position of the laser light and the spot position of the second laser light applied to the optical disc is projected on the light receiving means, a dividing line substantially parallel to the projected straight line is used. An optical disc device having a plurality of divided light receiving units. 12. The light emitting means, wherein the distance between the first light source and the second light source is 80 μm to 200 μm.
12. The optical disk device according to claim 11, wherein m is m. 13. The optical disk device according to claim 11, wherein the optical head includes a quarter-wave plate between the light emitting unit and the optical disk. 14. The optical disk device according to claim 11, wherein said optical head includes a Foucault prism between said beam splitter and said light receiving means. 15. A light receiving means for detecting a light receiving signal for generating a focus error signal by a plurality of light receiving sections divided by only a dividing line substantially parallel to the projected straight line. The optical disk device according to claim 11. 16. The light receiving means detects a light receiving signal for generating a reproduction signal from the optical disk by a plurality of light receiving sections divided only by a dividing line substantially parallel to the projected straight line. The optical disk device according to claim 11, wherein: 17. A diffraction grating for splitting a laser beam emitted from the light emitting unit into a plurality of light beams including a main beam and a sub-beam, between the light emitting unit and the beam splitter. And the light receiving means has a pair of light receiving portions on both sides in a direction substantially perpendicular to the projected straight line of the plurality of light receiving portions, and the pair of light receiving portions is divided by the diffraction grating. 12. The optical disk device according to claim 11, wherein a light receiving signal for generating a tracking error signal is detected by receiving the sub-beam of the plurality of light beams. 18. The light emitting means, wherein a straight line connecting the spot of the first laser light irradiated on the optical disc and the spot of the second laser light irradiated on the optical disc is formed on the optical disc. 12. The relative positional relationship between the first light source and the second light source is set so as to have an angle of 90 ° ± 10 ° with respect to a recording track. Optical disk device. 19. The optical head, comprising: a laser beam emitted from the light emitting unit in a direction substantially parallel to a signal recording surface of the optical disc between the beam splitter and the focusing unit. 12. The optical disk device according to claim 11, further comprising a deflecting member for deflecting light toward the optical disk. 20. The light emitting means, wherein the first light source and the second light source are arranged in a plane substantially parallel to a signal recording surface of the optical disk. 12. The optical disk device according to item 11.