JP2001236676A - Optical head and optical information medium recording/ reproducing device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect plural laser beams with a common photodetecting element using an optical head provided with plural semiconductor laser chips. SOLUTION: A double mirror is arranged having different reflection surfaces that reflect laser beams from plural semiconductor laser chips, thereby reducing inclination of incident beams on a photodetector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head for recording information on or reproducing information from an optical information medium such as an optical disk, and more particularly, to an optical head using a laser module equipped with a plurality of semiconductor laser light sources. The present invention relates to a head and an optical information medium recording / reproducing apparatus using the same.

[0002]

2. Description of the Related Art An optical information recording / reproducing apparatus such as an optical disk apparatus is required to have various functions in addition to miniaturization and thinning.

For example, a compact disk-recordable (CD-R), which has become popular as a writable optical disk, and a DVD (Digital Versatile Disc / Digital Video), which has recently been developed as a higher-density writable optical disk.
Disc), there is a remarkable demand for recording and reproducing both optical disks with the same small optical head. The laser wavelength suitable for recording and reproducing CD-R is about 780 nm, while the laser wavelength suitable for recording and reproducing DVD is about 660 nm.
nm, it is necessary to mount both a laser light source having a wavelength of about 780 nm and a laser light source having a wavelength of about 660 nm on the same optical head. Then, for example, Japanese Patent Laid-Open No. 10-261
No. 240 and Japanese Unexamined Patent Application Publication No. 11-25501 disclose a CD semiconductor laser chip having a wavelength of about 780 nm and a wavelength of about 6 nm.
A compact optical head that houses a 60 nm DVD semiconductor laser chip in a single package and combines a photodetector that receives a laser beam for a CD and a photodetector that receives a laser beam for a DVD in a single package is proposed. Have been.

Usually, beams emitted from different light emitting points are imaged at different positions by a lens system. Therefore, even in these optical heads, beams emitted from two semiconductor laser chips are imaged at different positions on the optical disk surface. And the reflected beams are imaged at different locations on the photodetector surface. Therefore, in FIG. 4 of JP-A-10-261240 and FIG. 5 of JP-A-11-25501,
The shapes of a photodetector for receiving a laser beam for CD having a wavelength of about 780 nm and a laser for receiving a laser beam for DVD having a wavelength of about 660 nm are shown. In the second embodiment of Japanese Patent Application Laid-Open No. H11-25501, as shown in FIG. 16, one laser beam is emitted by using a diffraction means 31 such as a Wollaston prism, a polarization selective hologram, or a wavelength selective hologram. There is disclosed a technique for changing the traveling direction so that the imaging positions of two laser beams on the surface of the photodetector 10 are matched to use a common photodetector.

[0005]

However, in the above-mentioned conventional example, a photodetector for receiving a laser beam for CD and a photodetector for receiving a laser beam for DVD are provided inside one photodetector. Not only will the size of the photodetector be increased, but also a signal processing circuit for CD for processing the output signal of the photodetector for CD and a signal for DVD for processing the output signal of the photodetector for DVD. There is a problem that a processing circuit is required.

Further, in the conventional example in which the photodetecting element is used in common, one laser beam has no effect and the other laser beam changes the traveling direction, such as a Wollaston prism, a polarization selective hologram, and a wavelength selective hologram. There is a problem that special diffraction means is required, and the cost of optical components of the optical head increases.

An object of the present invention is to provide an optical head for recording information on or reproducing information from an optical information medium using a plurality of laser light sources, without using expensive optical parts. An object of the present invention is to provide an optical head capable of sharing a photodetector for receiving a beam and an optical information medium recording / reproducing apparatus using the same.

[0008]

In order to achieve the above object, a plurality of laser light sources such as semiconductor laser chips having different wavelengths and a plurality of laser beams emitted from the laser light source are transmitted to an optical information medium such as an optical disk. Optical irradiating means such as a focus lens for irradiating as a spot, optical separating means such as a mirror for separating the reflected beam reflected from the optical information medium from the optical path from the laser light source to the information medium, and optical separating means An optical head having a photodetector such as a photodetector for detecting the reflected beam, and an optical information recording / reproducing apparatus using the same, wherein the optical separating means includes a plurality of laser beams which reflect laser beams of different wavelengths. Multiple reflecting surfaces, and multiple reflecting surfaces are connected to each other so as to reflect multiple laser beams incident from different directions in almost the same direction. Not a line, was so.

Further, the plurality of laser light sources are a plurality of semiconductor laser chips, which are housed in the same package.

Further, the plurality of laser light sources are a plurality of semiconductor laser light sources formed on the same semiconductor substrate.

The optical separating means is a wedge-shaped flat plate in which a plurality of optical surfaces into and out of which the beam enters and exits are not parallel to each other.
Reflection films reflecting different wavelengths were formed on a plurality of optical surfaces.

Further, the optical separating means is a block-shaped flat plate having a plurality of optical surfaces into and out of which a beam enters and exits, and has a plurality of non-parallel reflecting surfaces inside the block-shaped flat plate; Formed a reflective film that reflects different wavelengths.

A laser package containing a plurality of semiconductor laser light sources such as semiconductor laser chips having different wavelengths, a collimating lens for converting a plurality of laser beams emitted from the semiconductor laser light source into a parallel light beam, and a plurality of parallel light beams. An optical head having a focus lens that focuses the laser beam as an optical spot on an optical information medium such as an optical disc as a light spot, and a photodetector such as a photodetector that detects a reflected beam from the optical information medium, and using the same. The optical information recording / reproducing apparatus has a mirror between the collimating lens and the focus lens for guiding the reflected beam reflected by the optical information medium to the photodetector. The surfaces are wedge-shaped flat plates that are not parallel to each other, and a reflective film that reflects different wavelengths is Form was.

Further, a laser package containing a plurality of semiconductor laser light sources such as a plurality of semiconductor laser chips having different wavelengths, and a collimator for converging a plurality of laser beams emitted from the semiconductor laser light source to an optical information medium such as an optical disk as a light spot. An optical head having a condenser lens such as a lens system or a finite type focus lens combining a lens and a focus lens, and a light detecting means such as a photodetector for detecting a reflected beam from an optical information medium; and In the optical information medium recording and reproducing apparatus used, between the laser package and the condenser lens, having a mirror for guiding the reflected beam reflected by the optical information medium to the photodetector,
The mirror is a block-shaped flat plate in which a plurality of optical surfaces from which a beam enters and exits are parallel to each other, and has a plurality of non-parallel reflecting surfaces inside the block-shaped flat plate, and the plurality of reflecting surfaces reflect different wavelengths. A film was formed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a basic configuration of an optical head using the present invention. Reference numeral 1a denotes a DVD semiconductor laser chip which emits a laser beam 2a having a wavelength of λa = 660 nm, and 1b denotes a CD, CD-R or CD-RW semiconductor laser chip which emits a laser beam 2b having a wavelength of λb = 780 nm. I do. Reference numeral 3 denotes a laser package, which is a semiconductor laser chip 1a.
And 1b. Reference numeral 4 denotes a collimating lens which converts the laser beam for DVD 2a and the laser beam for CD 2b into parallel light beams. Reference numeral 5 denotes a focus lens having a substrate thickness of 0.6 mm.
DVD with a wavelength of 660 nm and a numerical aperture of 0.6
Optical disc, substrate thickness 1.2mm, wavelength used is 780
A lens with a variable entrance pupil diameter, a hologram element added to the entrance side, or a hologram element or ring on the entrance side lens surface suitable for both CD optical disks with a numerical aperture of about 0.5 nm. And the like with a band groove added.
Reference numeral 6 denotes a DVD optical disc, a CD optical disc, or a C
This shows a DR optical disk and a CD-RW optical disk. 7
Is a composite element in which a polarizing four-divided diffraction grating and a quarter-wave plate are laminated and integrated, and the polarizing four-divided grating is arranged facing the semiconductor laser chip side. Polarization 4
The split diffraction grating is made of, for example, a birefringent optical crystal plate or a liquid crystal plate. When the incident light is an ordinary ray, it transmits without diffracting, and when the incident light is an extraordinary ray, it functions as a diffraction grating. The four-division grating is divided into four parts in order to detect a focus shift detection signal and a track shift detection signal using a laser beam reflected by the optical disk 6.
Reference numeral 8 denotes a wedge-shaped double mirror according to the present invention, which reflects a laser beam having a wavelength of
A dielectric laminated film transmitting a laser beam of b = 780 nm is deposited, and a wavelength λa = 660 is provided on the optical surface 8b.
A dielectric laminated film that transmits a laser beam of nm and reflects a laser beam of wavelength λb = 780 nm is deposited.
Also, the optical surfaces 8a and 8b are not parallel but inclined wedge-shaped. 9 is a detection lens and 10 is a photodetector. The laser beam reflected by the wedge-shaped double mirror 8 is
The light is focused on the light receiving surface of the photodetector 10 by the detection lens 9.

In the embodiment shown in FIG. 1, as an example, a semiconductor laser chip 1a for DVD is arranged on the optical axis of a collimating lens 4 indicated by reference numeral 11.

The laser beam 2a emitted from the semiconductor laser chip 1a is converted into a parallel light beam parallel to the optical axis 11 by the collimator lens 4, and becomes a light spot 12a on the optical disk 6 by the focus lens 5. The laser beam 2a reflected by the optical disk 6 is converted into a parallel light beam parallel to the optical axis 11 by the focus lens 5, and the wedge-shaped double mirror 8
Incident on the optical surface 8a. The optical surface 8a is arranged at 45 degrees to the optical axis 11, and the laser beam 2a
Reflected by the optical surface 8a in a direction perpendicular to the optical axis 11,
The light is focused by the detection lens 9 at a position 13a on the photodetector 10. On the other hand, the laser beam 2 b emitted from the semiconductor laser chip 1 b is converted into a parallel light beam inclined by θ with respect to the optical axis 11 by the collimator lens 4, and becomes a light spot 12 b on the optical disk 6 by the focus lens 5.
The inclination angle θ of the laser beam 2b is approximately θ = d /, where, for example, the distance between the light emitting point of the semiconductor laser chip 1a and the light emitting point of the semiconductor laser chip 1b is d, and the focal length of the collimating lens 4 is fc. fc, d = 300 μm
And when fc = 17 mm, θ = 0.176 radians =
1.0 degrees. The laser beam 2 b reflected by the optical disk 6 is converted into a parallel light beam inclined by θ with respect to the optical axis 11 by the focus lens 5, and is converted into an optical surface 8 of the wedge-shaped double mirror 8.
After passing through a, the light is reflected by the optical surface 8b, passes through the optical surface 8a again, and is focused by the detection lens 9 to a position indicated by 13b on the photodetector 10. The optical surface 8b of the wedge-shaped double mirror 8 is inclined with respect to the optical surface 8a, and thus has the effect of canceling the inclination angle θ of the laser beam 2b. Then, the traveling direction of the laser beam 2b reflected by the wedge-shaped double mirror 8 is in the same direction as the laser beam 2a, so that the focusing position 13b of the laser beam 2b is the same as the focusing position 13a of the laser beam 2b. can do.

FIG. 2 shows an optical surface 8b of the double wedge mirror 8.
FIG. 4 is a diagram for explaining the action of canceling the tilt angle θ of the laser beam 2b. 21 indicates a normal line of the optical surface 8a,
When the laser beam 2b enters the optical surface 8a, the incident angle is i, the refraction angle is γ, the refractive index of the wedge-shaped double mirror 8 is n,
Then, from the law of refraction, sini = n * sinγ. Reference numeral 22 also indicates the normal to the optical surface 8a, and the laser beam 2
When b exits the optical surface 8a, n * sin γ ′ = sini ′, where γ ′ is the incidence angle and i ′ is the emission angle. Dotted line 23 indicates a plane parallel to optical surface 8a and optical surface 8b
Is inclined α with respect to the surface 23. The dotted line 24 indicates the normal of the surface 23, 25 indicates the normal of the optical surface 8b, and the normal 25 is inclined by α from the normal 24. The laser beam 2b is applied to the optical surface 8b
, The incident angle is γ + α and the reflection angle is γ′-α
Since the angle of incidence and the angle of reflection are equal according to the law of reflection, γ
+ Α = γ′−α or α = (γ′−γ) / 2. For example, when n = 1.5 and the inclination angle of the laser beam 2b is θ =
If it is 1.0 degree, i = 45 degrees-θ = 44 degrees and γ = 2
7.588 degrees, while i '= 45 degrees to γ' = 28.12
6 degrees. From this, α = (γ′−γ) /2=0.2
69 degrees. Therefore, the optical surface 8 of the wedge-shaped double mirror 8
By setting the angle between b and the optical surface 8b to 0.269 degrees, the tilt angle θ of the laser beam 2b can be canceled.

In this embodiment, for example, when the laser beams 2a and 2b emitted from the semiconductor laser chips 1a and 1b are incident on the composite element 7 composed of a polarizing four-division grating and a quarter-wave plate, for example, The light is incident as a light beam, and the polarized diffraction grating portion is transmitted as it is without being diffracted, and is converted into circularly polarized light by the quarter-wave plate of the composite element 7. The laser beams 2a and 2b reflected by the optical disk become extraordinary rays by the quarter-wave plate of the composite element 7, and are diffracted by the polarizing four-division diffraction grating.

FIG. 3 shows an example of a diffraction grating pattern of a four-divided diffraction grating in the composite element 7, and boundary lines 31 and 32 are shown.
Is divided into four regions. The circle 33 indicates the laser beam 2a or 2b, and four +
The light is separated into first-order diffracted light and four -1st-order diffracted lights. In the diffraction gratings of the four regions, the directions of the grating grooves are different, but the intervals between the grating grooves are equal. Therefore, the eight ± first-order diffracted lights have different diffraction directions but the same diffraction angles. When such eight diffracted lights are condensed on the light receiving surface of the photodetector 10 by the detection lens 9, they converge as eight spots on a concentric circle centered on the position 13a or 13b.

FIG. 4 shows a light receiving surface of the photodetector 10. 4
The eight black quarter circles indicated by 1a
Shows a laser beam 2a having a wavelength λa reflected by and divided by a 4-division diffraction grating, and is located on the circumference of a circle 42a centered on the position 13a. The eight unfilled quarter circles 41b indicate the laser beam 2b of the wavelength λb reflected by the optical disk 6 and separated by the four-division grating, and are on the circumference of the circle 42b centered on the position 13b. The centers of circles 42a and 42b coincide. Reference numerals 43a and 43b denote photodetectors for obtaining a defocus detection signal. The photodetectors 43a and 43b are opposed to each other and are formed as a set of four sets, each of which has a laser beam 41a having a wavelength λa or a wavelength λa. λb
Of the laser beam 41b. As the defocus detection method, a knife edge method (Fouco method) using a four-divided beam is used, and a defocus detection signal can be obtained by calculating the difference between the output signals of the two light receiving elements in each set. However, in the present embodiment, the light receiving elements are connected to each other by a conductive thin film 44 of aluminum or the like as shown in the figure, and the output signals from the A terminal and the B terminal of the wire bonding pad 45 are subjected to a difference operation to obtain a defocus. Obtain a detection signal. Reference numeral 46 denotes four photodetectors for obtaining a track shift detection signal and an information reproduction signal, which are connected to the C terminal, the D terminal, the E terminal, and the F terminal of the pad 45.

FIG. 5 is a block diagram of a signal operation circuit for obtaining a focus shift detection signal, a track shift detection signal, and an information reproduction signal. Reference numeral 51 denotes a differential circuit for subtracting output signals from the A terminal and the B terminal of the wire bonding pad 45 shown in FIG. 4, and outputs a defocus detection signal 52. 53-1 is an addition circuit for adding the output signals from the C terminal and the D terminal, and 53-2 is an addition circuit for adding the output signals from the E terminal and the F terminal. 53-
3 is an output signal of the addition circuit 53-1 and the addition circuit 53-2.
And a push-pull type track shift detection signal 54 when an optical disc having a guide groove or the like is used. 53-4 is an addition circuit 5
An addition circuit for adding the output signal of 3-1 and the output signal of the addition circuit 53-2 outputs an information reproduction signal 55.
56-1 is an addition circuit for adding the output signals from the C terminal and the E terminal, and 56-2 is an addition circuit for adding the output signals from the D terminal and the F terminal. Reference numeral 56-3 denotes a differential circuit for subtracting the output signal of the addition circuit 56-1 and the output signal of the addition circuit 56-2, and a phase difference type track shift detection signal when an optical disk having guide pits or the like is used. 57 is output. These focus shift detection signals and track shift detection signals are supplied to the lens actuator, and the focus lens 5 attached to the lens actuator is driven in the optical axis direction and the disk radial direction, thereby performing automatic focus control and track following control. Can be achieved.

FIGS. 9A and 9B show the structure of an optical disk apparatus using this embodiment, wherein FIG. 9A is a top view and FIG. 9B is a side view. Reference numeral 91 denotes a housing of the optical disk device. Reference numeral 92 denotes a motor, which is attached to the housing 91 of the optical disk device.
The optical disk 6 is rotated via the shaft 93. 94
Denotes an optical head, in which the optical components shown in FIG. 1 are stored. Reference numeral 95 denotes a package containing the semiconductor laser chips 1a and 1b shown in FIG. Reference numeral 96 denotes a lens actuator to which the focus lens 5 shown in FIG. 1 is attached. 97 is an access mechanism attached to the optical head 94, and 98 is a rail attached to the housing 91 of the optical disk device. The optical head 94 has an access mechanism 97.
This allows the disk 6 to move on the rail 98 in the radial direction of the disk 6. The laser beam emitted from the semiconductor laser chip mounted on the package 95 is emitted from the optical head 94 via the focus lens of the lens actuator 96 and is applied to the rotating optical disc 6. The reflected beam again enters the optical head 94 via the focus lens, and is received by the photodetector 10 shown in FIG. 1 to obtain a focus shift detection signal, a track shift detection signal, and an information reproduction signal.

FIG. 10 shows the structure of the lens actuator 96 used in this embodiment. 2A is a top view as viewed from the direction of the optical disk 6. FIG. 101 is a lens holder,
The focus lens 5 and the coil 104 are attached, and are held on the holding table 103 by the spring 102. A magnet 105 is provided beside the spring 102, and the magnet 105 and the holder 103 are fixed to the optical head housing. (B) is a side sectional view of the lens actuator 96 as viewed from the lateral direction. A solid line 106 indicates the surface of the optical head housing for fixing the magnet 105, the holding table 103, and the like. Lens holder 1
Reference numeral 01 has a box-shaped structure so as to be light and to increase the rigidity of a portion for holding the focus lens 5. In particular, the horizontal plate portion 107 is essential for increasing rigidity. The laser beams 2a and 2b are made incident from the right side of the drawing, that is, from the circumferential direction of the disk, and are reflected by the mirror. When the defocus detection signal 52 shown in FIG. 5 is applied to the coil 104, the electromagnetic force generated between the coil 104 and the magnet 105 causes
The lens holder 101 moves in the vertical direction on the paper surface of FIG. 10B, and the focus control can be achieved. Also,
When the push-pull type track shift detection signal 54 or the phase difference type track shift detection signal 57 is supplied to the coil 104, the electromagnetic force generated between the coil 104 and the magnet 105 causes
The lens holder 101 moves in the vertical direction on the paper surface of FIG. 10A to achieve tracking control.

Referring to FIG. 6, another embodiment of the present invention will be described. FIG. 6 shows a basic configuration of another optical head using the present invention. Reference numeral 61a denotes a DVD semiconductor laser chip which emits a laser beam 62a having a wavelength λa = 660 nm.
b denotes a semiconductor laser chip for CD, CD-R, and CD-RW, which emits a laser beam 62b having a wavelength λb = 780 nm. Reference numeral 63 denotes a block-shaped flat plate or prism type double mirror according to the present invention, the outer shape of which is, for example, a cubic shape. Optical surfaces 63c and 63 on which the laser beam enters and exits
Since d is parallel, the diverging laser beams 62a and 62
Unnecessary aberration such as coma does not occur in 2b.
Inside the double mirror 63, a reflection surface 63a on which a dielectric laminated film that reflects a laser beam having a wavelength λa = 660 nm and transmits a laser beam having a wavelength λb = 780 nm is deposited, and a laser beam having a wavelength λa = 660 nm is transmitted. Wavelength λb =
It has a reflecting surface 63b on which a dielectric laminated film that reflects a 780 nm laser beam is deposited, and the reflecting surfaces 63a and 63b are not parallel but inclined. Reference numeral 64 denotes a rising mirror. Numeral 65 denotes a four-division diffraction grating which is divided into four parts as shown in FIG. 2 in order to detect a focus shift detection signal and a track shift detection signal using a laser beam reflected by an optical disk. ing. Reference numeral 66 denotes a finite focus lens, which controls the laser beam 62a emitted from the semiconductor laser chip 61a and the semiconductor laser chip 61.
The laser beam 62b emitted from b is focused on the optical disk surface. As described above, the focus lens 66 is suitable for both DVD optical disks and CD optical disks and has a variable entrance pupil diameter, a lens with a hologram element added on the incident side, and a hologram on the lens surface on the incident side. An element or an annular groove can be used. Reference numeral 67 denotes a photodetector, which indicates a point 68 at which the convergence positions of the laser beams 62a and 62b when there is no 4-division diffraction grating 65.
a and 68b. Reflecting surface 63a inside double mirror 63
And 63b are tilted, so that the laser beams 62a and 6b
The virtual focusing positions 68a and 68b of 2b can be matched. The light receiving surface of the photodetector 67 has a shape as shown in FIG. 4 described above, and the virtual focusing positions 68a and 68b on the surface of the photodetector 67 correspond to the positions 13a and 13b in FIG. A four-division diffraction grating 65 and a photodetector 68 for obtaining a focus shift detection signal, a track shift detection signal, and an information reproduction signal.
Is the same as the operation described in the above embodiment,
Omitted.

FIG. 7 shows the reflecting surface 6 inside the double mirror 63.
It is a figure explaining operation of 3a and 63b. The laser beam 62a emitted from the semiconductor laser chip 61a forms an image at the focal point 71a by the focus lens 66, is reflected by the disk 72, and is focused by the focus lens 66 toward the point 61a. The laser beam 62b emitted from the semiconductor laser chip 61b is
6 forms an image on the focal point 71b, reflects off the disk 72,
The light is focused toward the point 61b by the focus lens 66. When these reflected beams are separated by a normal mirror 73 having one reflecting surface, the laser beam 62a
Focusing on 4a, laser beam 62b focuses on point 74b. The distance between the convergence points 74a and 74b is equal to the distance between the semiconductor laser chips 61a and 61b, for example, about 300 μm. Therefore, a dedicated light receiving element for receiving the laser beam 62a and a dedicated light receiving element for receiving the laser beam 62b are required. On the other hand, when the double mirror 63 of the present invention is used, the laser beam 62a transmits through the reflecting surface 63b, is reflected by the reflecting surface 63a, and is focused on a point 68a, and the laser beam 62b is reflected on the reflecting surface 63b, and is focused on a point 68b. I do. The reflecting surfaces 63a and 63b are not parallel as shown in the drawing, but are inclined with respect to each other. By appropriately setting the angle between the reflecting surfaces 63a and 63b, the focal points 63a and 63b can be matched. .
Moreover, since the optical surfaces 63c and 63d on which the laser beam enters and exits are parallel, the divergent laser beam 62a
Unnecessary aberrations such as coma do not occur in the lens 62b.

In the above embodiment, the laser light source is one in which a plurality of semiconductor laser chips are arranged in parallel or they are housed in the same package.
The laser oscillation regions having different wavelengths may be provided in one semiconductor laser chip as shown in FIG. FIG.
Reference numeral 81 denotes a two-laser chip in which two laser oscillation regions are formed by a semiconductor process. Each laser oscillation region emits a laser beam 82a and a laser beam 82b. The two semiconductor laser chips 1a and 1 explained in FIG.
b and the two semiconductor laser chips 61a described in FIG.
By using the two laser chips 81 instead of the laser module 61b, a laser module that is easier to assemble can be realized.

[0029]

As described above, according to the present invention, a new expensive optical component is used in an optical head for recording or reproducing information on an optical information medium using a plurality of laser light sources. It is possible to realize an optical head that can use a common photodetector for receiving a plurality of laser beams without using a laser beam, and an optical information medium recording / reproducing apparatus using the same.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical head according to a first embodiment.

FIG. 2 is a view for explaining the principle in the first embodiment.

FIG. 3 is a configuration diagram of a diffraction grating portion in FIG.

FIG. 4 is a configuration diagram of a photodetector in FIG.

FIG. 5 is a configuration diagram of a signal operation circuit in FIG. 1;

FIG. 6 is a configuration diagram of an optical head according to a second embodiment.

FIG. 7 is a view for explaining the principle in the second embodiment.

FIG. 8 is a configuration diagram of another semiconductor laser chip in the present embodiment.

FIG. 9 is a configuration diagram of an optical disk device using the present embodiment.

FIG. 10 is a configuration diagram of a lens actuator in FIG. 9;

[Explanation of symbols]

 1a, 1b semiconductor laser chip 3 laser package 4 collimator lens 5 focus lens 6 optical disk 8 wedge double mirror 9 detection lens 10 photodetector 61a, 61b semiconductor laser chip 66 focus lens 63… Double mirror 67… Photodetector

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D119 AA05 AA41 BA01 CA09 DA01 DA05 EA02 EA03 EC45 EC47 FA05 FA08 JA17 JA64 KA02 KA17 KA21 KA22

Claims (7)

[Claims] 1. A plurality of laser light sources having different wavelengths, an optical irradiation means for irradiating an optical information medium with a plurality of laser beams emitted from the laser light source as a light spot, and a reflection reflected by the optical information medium An optical head comprising: an optical separating means for separating a beam from an optical path from the laser light source toward the information medium; and a light detecting means for detecting the reflected beam separated by the optical separating means, and using the same. In an optical information recording / reproducing apparatus, the optical separating means includes a plurality of reflecting surfaces for reflecting laser beams of different wavelengths, and reflects the plurality of laser beams incident from different directions in substantially the same direction. An optical head, wherein the plurality of reflecting surfaces are not parallel to each other, and an optical information medium recording / reproducing apparatus using the same. 2. The optical head according to claim 1, wherein the plurality of laser light sources are a plurality of semiconductor laser chips and housed in the same package. An optical head and an optical information medium recording / reproducing apparatus using the same. 3. The optical head according to claim 1, wherein the plurality of laser light sources are a plurality of semiconductor laser light sources formed on the same semiconductor substrate. And an optical information recording / reproducing apparatus using the same. 4. An optical head according to claim 1, 2 or 3, and an optical information recording / reproducing apparatus using said optical head, wherein said optical separating means comprises a plurality of optical surfaces through which a beam enters and exits. Are wedge-shaped flat plates that are not parallel to each other, and reflection films that reflect different wavelengths are formed on the plurality of optical surfaces, and an optical information recording / reproducing apparatus using the same. 5. The optical head according to claim 1, 2 or 3, and an optical information recording / reproducing apparatus using the same, wherein the optical separating means comprises a plurality of optical surfaces through which a beam enters and exits. Are block-shaped flat plates parallel to each other, have a plurality of non-parallel reflective surfaces inside the block-shaped flat plate, and a reflective film that reflects different wavelengths is formed on the plurality of reflective surfaces. An optical head and an optical information recording / reproducing apparatus using the same. 6. A laser package accommodating a plurality of semiconductor laser light sources having different wavelengths, a collimator lens for converting a plurality of laser beams emitted from the semiconductor laser light source into a parallel light beam, and a plurality of parallel laser light beams. An optical head having a focus lens that focuses as an optical spot on an optical information medium as a light spot, and a light detection unit that detects a reflected beam from the optical information medium, and an optical information medium recording / reproducing apparatus using the same, A mirror for guiding a reflected beam reflected by the optical information medium to the photodetector between the collimator lens and the focus lens, the mirror including a wedge having a plurality of optical surfaces into and out of which the beams enter and exit; Wherein the plurality of optical surfaces are provided with reflection films for reflecting different wavelengths. De and the optical information medium recording and reproducing apparatus using the same. 7. A laser package accommodating a plurality of semiconductor laser light sources having different wavelengths, a condenser lens for focusing a plurality of laser beams emitted from the semiconductor laser light source as an optical spot on an optical information medium, and An optical head having light detection means for detecting a reflected beam from an information medium, and an optical information medium recording / reproducing apparatus using the same, wherein the optical information medium is reflected between the laser package and the condenser lens. A mirror for guiding the reflected beam to the photodetector, the mirror is a block-shaped flat plate having a plurality of optical surfaces into and out of which the beam enters and exits,
An optical head comprising: a plurality of non-parallel reflecting surfaces inside the block-shaped flat plate; and a reflecting film reflecting different wavelengths formed on the plurality of reflecting surfaces. Optical information medium recording / reproducing device.