JPH1139693A - Integrated optical element, optical pickup device and recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deal with two kinds of optical disks with different standards by also light receiving return light of respective light beams from two light emitting elements emitting the light beams having different wavelengths with two light receiving elements. SOLUTION: An integrated optical element 11 is provided with first, second laser diodes 17, 19 respectively emitting light beams with different wavelengths to receive the return light of respective light beams by first, second photodetectors 13, 14 also. Thus, a regenerative signal and a control signal are read out from optical disks with different optimum wavelengths such as a CD and a CD-ROM, and the constitution is simplified. At this time, when the first laser diode 17 emits the light beam of the wavelength 780 nm, and the second laser diode 19 emits the light beam of the wavelength 650 nm, by using two optical thin films respectively having wavelength dependency, the light receiving amount of the first photodetector 13 is nearly equalized with the same of the second photodetector 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated optical element in which a light emitting element and a light receiving element corresponding to two kinds of optical disks are integrated and integrated, and an optical pickup device and a recording / reproducing apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, CDs have been used as optical recording media.
(Compact Disc), a read-only optical disk,
A write-once optical disc called a CD-R (Compact Disc-Recordable) is widely used.

[0003] In this CD or CD-R, recording tracks are formed at a pitch of about 1.6 µm on a disk having a diameter of 12 cm, and optimum reproduction and recording characteristics for a light beam having a wavelength of about 780 nm. It is standardized to exhibit

On the other hand, as an optical recording medium suitable for multimedia use, a DVD (Digital Versatile Disc / Digi
An optical disc called “tal Video Disc” has been developed and put into practical use. This DVD is a disk (diameter 12 cm) of the same size as a CD or CD-R, but uses a light beam with a wavelength of about 650 nm and an objective lens with an NA of about 0.6 to achieve a narrow pitch. And a shorter pit length are realized, and the recording capacity is remarkably increased as compared with a CD or a CD-R.

[0005] With the development of a new optical disk as described above, a recording / reproducing apparatus is compatible with the new optical disk and has compatibility with a conventional optical disk. Things are desired.

In response to such demands, a recording / reproducing apparatus capable of supporting both CDs, CD-Rs and DVDs has been proposed.
There has been proposed a recording / reproducing apparatus including an optical system for CD or CD-R and an optical system for DVD.

[0007]

However, such a recording / reproducing apparatus requires an output terminal corresponding to each optical pickup device, and
The number of components of the optical system increases, which leads to an increase in the size of the device.

Therefore, the present invention can cope with two kinds of optical discs having different standards by integrating and integrating two light emitting elements and light receiving elements which emit light beams of different wavelengths. It is an object of the present invention to provide an integrated optical element capable of reducing the number of components and realizing the miniaturization of the device, and an optical pickup device and a recording / reproducing device using the same.

[0009]

An integrated optical element according to the present invention has two inclined surfaces, and a prism provided on first and second light receiving elements, and two prisms of the prism. First and second light emitting elements for emitting light beams having different wavelengths toward the inclined surface are provided.

This integrated optical element has a first optical path branching film on one inclined surface of the prism and a second optical path branching film on the other inclined surface of the prism.

Further, the integrated optical element has a semi-transmissive film between the first and second light receiving elements and the bottom surface of the prism, and a highly reflective film on the upper surface of the prism.

According to this integrated optical element, the light beam emitted from the first light emitting element is reflected by the first optical path branching film provided on one inclined surface of the prism and travels toward the optical recording medium. Then, the return light from the optical recording medium passes through the first optical path branching film and enters the prism,
Part of the light passes through the semi-transmissive film and is received by the first light receiving element. Then, the other part is reflected by the semi-transmissive film, further reflected by the highly reflective film, and travels to the second light receiving element. A part of the return light heading for the second light receiving element is transmitted through the semi-transmissive film and received by the second light receiving element.

The light beam emitted from the second light emitting element is reflected by the second optical path branching film provided on the other inclined surface of the prism and travels toward the optical recording medium. Then, return light from the optical recording medium passes through the second optical path branching film, enters the prism, and partially passes through the semi-transmissive film and is received by the second light receiving element. Then, the other part is reflected by the semi-transmissive film, further reflected by the highly reflective film, and travels to the first light receiving element. A part of the return light heading for the first light receiving element is transmitted through the semi-transmissive film and received by the first light receiving element.

An optical pickup device according to the present invention integrates an integrated optical element, a light beam emitted from the integrated optical element, irradiates the collected light beam onto an optical recording medium, and integrates return light from the optical recording medium. An objective lens to be introduced into the optical element.

The integrated optical element of the optical pickup device has two inclined surfaces, and a prism provided on the first and second light receiving elements and a prism provided on the two inclined surfaces. First and second light-emitting elements for emitting light beams of different wavelengths toward each other;
First and second optical path branching films provided on the two inclined surfaces,
A semi-transmissive film is provided between the first and second light receiving elements and the bottom surface of the prism, and a highly reflective film is provided on the upper surface of the prism.

According to this optical pickup device, the light beam emitted from the first light emitting element of the integrated optical element is
The light is reflected by the first optical path branching film provided on one of the inclined surfaces of the prism, condensed by the objective lens, and irradiated on the signal recording surface of the optical recording medium.

The return light from the optical recording medium toward the prism through the objective lens passes through the first optical path branching film, enters the prism, and partially passes through the semi-transmissive film to form the first light. The light is received by the light receiving element. Then, the other part is reflected by the semi-transmissive film, further reflected by the highly reflective film, and travels to the second light receiving element. A part of the return light heading for the second light receiving element is transmitted through the semi-transmissive film and received by the second light receiving element.

The light beam emitted from the second light emitting element of the integrated optical element is reflected by the second optical path branching film provided on the other inclined surface of the prism, and is condensed by the objective lens to be condensed. Irradiation is performed on the signal recording surface of the recording medium.

The return light from the optical recording medium toward the prism through the objective lens passes through the second optical path branching film and enters the prism, and a part of the light passes through the semi-transmissive film and passes through the second light path branching film. The light is received by the light receiving element. Then, the other part is reflected by the semi-transmissive film, further reflected by the highly reflective film, and travels to the first light receiving element. A part of the return light heading for the first light receiving element is transmitted through the semi-transmissive film and received by the first light receiving element.

The recording / reproducing apparatus according to the present invention comprises an integrated optical element, and a light beam emitted from the integrated optical element, which is condensed and irradiated on a signal recording surface of an optical recording medium.
Objective lens for introducing return light from the optical recording medium into the integrated optical element, driving means for driving the optical recording medium, objective lens supporting means for movably supporting the objective lens in two axial directions, and optical recording medium A signal processing circuit for generating a reproduction signal and a control signal based on a signal detected from the return light from the optical disc, and a direction in which the objective lens support means is brought into or out of contact with the optical recording medium in the radial direction based on the control signal. And a moving means for moving the object.

The integrated optical element of the recording / reproducing apparatus has a prism having two inclined surfaces and provided on the first and second light receiving elements, and a prism directed to the two inclined surfaces of the prism. First and second light emitting elements for emitting light beams having different wavelengths, first and second optical path branching films provided on two inclined surfaces of the prism, and first and second light receiving elements And a semi-transmissive film provided between the bottom surfaces of the prisms, and a highly reflective film provided on the upper surface of the prism.

According to this recording / reproducing apparatus, the light beam emitted from the first light emitting element of the integrated optical element is reflected by the first optical path branching film provided on one inclined surface of the prism, and the objective lens And is radiated on the signal recording surface of the optical recording medium driven by the driving means.

The return light from the optical recording medium to the prism through the objective lens passes through the first optical path branching film and enters the prism, and a part of the light passes through the semi-transmissive film and enters the first prism. The light is received by the light receiving element. Then, the other part is reflected by the semi-transmissive film, further reflected by the highly reflective film, and travels to the second light receiving element. A part of the return light heading for the second light receiving element is transmitted through the semi-transmissive film and received by the second light receiving element.

The light beam emitted from the second light emitting element of the integrated optical element is reflected by the second optical path branching film provided on the other inclined surface of the prism, and is condensed by the objective lens. The light is irradiated onto the signal recording surface of the optical recording medium driven by the driving means.

The return light from the optical recording medium toward the prism through the objective lens passes through the second optical path branching film, enters the prism, and partially passes through the semi-transmissive film to form the second light path. The light is received by the light receiving element. Then, the other part is reflected by the semi-transmissive film, further reflected by the highly reflective film, and travels to the first light receiving element. A part of the return light heading for the first light receiving element is transmitted through the semi-transmissive film and received by the first light receiving element.

Further, according to the recording / reproducing apparatus, the signal processing circuit controls the reproduction signal, the focus error signal, the tracking error signal, and the like based on the light receiving signals output from the first and second light receiving elements. And generate a signal. Then, based on the control signal generated by the signal processing circuit, the moving means moves the optical system support means in a radial direction of the optical recording medium or in a direction of coming into contact with or separating from the optical recording medium.

[0027]

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

The recording / reproducing apparatus 1 according to the present invention uses a CD (Co
mpact Disc) or CD-R (Compact Disc-Recordable)
And DVD (Digital Versatile Disc / Digital Video
A recording / reproducing apparatus corresponding to two types of optical discs having different standards such as a disc), a spindle motor 3 for rotating and driving the optical disc 2 and a light beam irradiating a signal recording surface of the optical disc 2 as shown in FIG. An optical pickup device 4 for detecting return light from the optical disk 2; a signal processing circuit 5 for generating a reproduction signal and a control signal based on the return light detected by the optical pickup device 4; From optical disk 2
Focus / track servo mechanism 6 for controlling focusing and tracking by operating a light beam applied to the optical disk, access mechanism 7 for moving optical pickup device 4 in the radial direction of optical disk 2, and signal processing circuit 5
And a system controller 8 for controlling the spindle motor 3, the focus / track servo mechanism 6, and the access mechanism 7 based on the signal generated by the above.

The drive of the spindle motor 3 is controlled by a system controller 8. The spindle motor 3 rotates the optical disc 2 so that the light beam irradiated on the optical disc 2 while moving in the radial direction of the optical disc 2 moves on the optical disc 2 at a predetermined speed.

The optical pickup device 4 irradiates a light beam onto the signal recording surface of the optical disk 2 rotated and driven by the spindle motor 3, detects return light reflected on the signal recording surface of the optical disk 2, and performs a signal processing circuit 5. Output to At this time, the optical pickup device 4 emits a light beam having a wavelength optimal for reproducing the optical disk 2 depending on the type of the optical disk 2 that is driven to rotate. For example, if the optical disk 2 to be rotationally driven is a CD, the optical pickup device 4 emits a light beam having a wavelength of about 780 nm.
A light beam of 0 nm is emitted.

The signal processing circuit 5 demodulates a reproduction signal and a control signal obtained based on the return light detected by the optical pickup device 4 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 5 is sent to an external computer or the like via the interface 9 if it is for data storage of a computer. If the reproduced signal is for audiovisual use, the signal is subjected to digital / analog conversion by the D / A conversion unit of the D / A / A / D converter 10 and transmitted to audiovisual equipment.

The control signal demodulated by the signal processing circuit 5 is output to the system controller 8. The system controller 8 drives the focus / track servo mechanism 6 based on the control signal, and operates a light beam emitted from the optical pickup device 4 onto the signal recording surface of the optical disk 2 to perform focusing control and tracking. Perform control.

The access mechanism 7 causes the optical pickup device 4 to perform a feed operation in the radial direction of the optical disk 2 based on a signal supplied from the system controller 8.

As shown in FIG. 2, the optical pickup device 4 is an integrated optical device in which two light emitting elements and light receiving elements for emitting light beams of different wavelengths are mounted on a semiconductor substrate and sealed in a package. The element 11 and a light beam emitted from the integrated optical element 11 are condensed and irradiated on the signal recording surface of the optical disk 2, and return light reflected on the signal recording surface of the optical disk 2 is reflected by the integrated optical element 11. And an objective lens 30 to be introduced therein.

The objective lens 30 is moved in the radial direction of the optical disk 2 and the optical disk 2 by a lens support member (not shown).
It is supported so as to be movable in two axial directions of coming and going.

The objective lens 30 includes the integrated optical element 11
The focus / track servo mechanism 6 moves the lens support member on the basis of the control signal generated by the signal processing circuit 5 in the radial direction of the optical disk 2 or in the direction in which the optical disk 2 comes into contact with or separates from the optical disk 2. Be moved. The objective lens 30 condenses the light beam emitted from the integrated optical element 11 so that the light beam is always focused on the signal recording surface of the optical disk 2, and also focuses the collected light beam. The track of the optical disk 2 is made to follow.

The integrated optical element 11 is, as shown in FIG.
On a semiconductor substrate 12, first and second photodetectors 13 and 14, which are light receiving elements, are provided. The first and second photodetectors 13 and 14 are divided in a direction corresponding to the radial direction of the optical disc 2 so that each has a plurality of sensor units. The first and second photodetectors 13 and 14 are connected to the signal processing circuit 5 via connection terminals (not shown).

On the semiconductor substrate 12, a prism 15 is provided on the first and second photodetectors 13 and 14. The prism 15 has a bottom surface 15a and a top surface 15b that are parallel to each other, and a bottom surface 15a.
First inclined surface 1 inclined at a predetermined inclination angle with respect to
5c and a second inclined surface 15d inclined at an angle opposite to the first inclined surface 15c with respect to the bottom surface 15a. The first inclined surface 15c and the second inclined surface 15
d is orthogonal to the bottom surface 15a and the top surface 15b.
a and the upper surface 15b are symmetrical with respect to a surface that bisects each of them.

The prism 15 is provided on the semiconductor substrate 12 such that the bottom surface 15 a is in contact with the semiconductor substrate 12 and faces the first and second photodetectors 13 and 14.

On the semiconductor substrate 12, a first laser diode 17 for emitting a light beam toward the first inclined surface 15c of the prism 15 while being supported by the first support substrate 16 is provided. Have been. In this example, the first laser diode 17 is a light emitting element for CD and CD-R, and emits a light beam having a wavelength of about 780 nm.

Further, on the semiconductor substrate 12, a second laser diode 19 for emitting a light beam toward the second inclined surface 15d of the prism 15 while being supported by the second support substrate 18 is provided. Have been. The second laser diode 19 is a light emitting element for DVD in this example, and emits a light beam having a wavelength of about 650 nm.

The first and second laser diodes 17 and 19 are arranged so as to be linearly arranged on the semiconductor substrate 12 with the first and second photodetectors 13 and 14 when projected onto a plane. 1st and 2nd photodetector 1
It is arranged on the side of 3,14.

On the first inclined surface 15c of the prism 15,
As shown in FIG. 4, a first optical path branching film 20 that is semi-transmissive to a light beam emitted from the first laser diode 17 is provided. This first optical path branching film 2
0 reflects a part of the light beam emitted from the first laser diode 17 and makes it incident on the objective lens 30, and transmits a part of the return light reflected on the signal recording surface of the optical disk 2. , Into the prism 15.

The second inclined surface 15d of the prism 15
Is provided with a second optical path branching film 21 which is semi-transmissive to the light beam emitted from the second laser diode 19. The second optical path branching film 21 reflects a part of the light beam emitted from the second laser diode 19 and makes it incident on the objective lens 30, and the return light reflected on the signal recording surface of the optical disk 2. Are transmitted through the prism 15 and enter the prism 15.

The light beam emitted from the first laser diode 17 and the light beam emitted from the second laser diode 19 are provided on the bottom surface 15 a of the prism 15 at least at positions facing the first and second photodetectors 13 and 14. Semi-transmissive film 2 having a semi-permeability for both of the light beams to be transmitted
2 are provided. Also, the upper surface 15b of the prism 15
On the high reflection film 2 having a high reflectance for both the light beam emitted from the first laser diode 17 and the light beam emitted from the second laser diode 19
3 are provided.

The semiconductor substrate 12 on which the prism 15, the first and second photodetectors 13 and 14, and the first and second laser diodes 17 and 19 are mounted has a package member 24 having an opening 24a on the upper surface side. Housed inside. The opening 2 of the package member 24
By closing the cover glass 4a with the cover glass 25, these prisms 15 and the first and second photodetectors 1 are removed.
3, 14, first and second laser diodes 17, 19
And the like are packaged as an integrated optical block so as to be shielded from the outside air.

The integrated optical element 11 configured as described above
Is supported by an integrated optical element support member (not shown) so as to be movable in the radial direction of the optical disc 2. The integrated optical element 11 is fed in the radial direction of the optical disk 2 by the access mechanism 7 moving the integrated optical element support member based on a signal supplied from the system controller 8.

Next, an operation of reading a reproduction signal and a control signal from the optical disk 2 by the recording / reproducing apparatus 1 configured as described above will be described.

First, the case where a CD is used as the optical disk 2 will be described with reference to FIGS. 5A and 5B.

When a drive voltage is supplied and an external signal is input to the system controller 8, the system controller 8 drives the spindle motor 3 to rotate, thereby rotating the optical disk 2 chucked by the spindle motor 3, and As shown in FIG. 5A, a light beam having a wavelength of about 780 nm is emitted from the first laser diode 17 provided in the integrated optical element 11 of the optical pickup device 4.

The light beam emitted from the first laser diode 17 is applied to the first optical path branching film 20 provided on the first inclined surface 15c of the prism 15. Part of the light beam applied to the first optical path branching film 20
Is reflected by the optical path branching film 20 and enters the objective lens 30.

The light beam incident on the objective lens 30 is condensed by the objective lens 30 and is focused and irradiated on the signal recording surface of the rotating optical disc 2. Optical disk 2
The return light of the light beam including the signal component reflected by the signal recording surface is again condensed by the objective lens 30 and travels to the integrated optical element 11.

The return light of the light beam directed toward the integrated optical element 11 is again irradiated on the first optical path branching film 20 provided on the first inclined surface 15c of the prism 15. A part of the return light of the light beam applied to the first optical path branching film 20 is the first light.
And enters the prism 15 from the first inclined surface 15c.

The return light of the light beam entering the prism 15 from the first inclined surface 15c is refracted at the time of incidence and travels toward the first photodetector 13. A part of the return light of the light beam toward the first photodetector 13 is the prism 1
5 and the first and second photodetectors 1
The light passes through the semi-transmissive film 22 provided between 3 and 14, and another part is reflected by the semi-transmissive film 22.

Return light of the light beam transmitted through the semi-transmissive film 22 is received by the first photodetector 13 as shown in FIG. On the other hand, the return light of the light beam reflected by the semi-transmissive film 22 is reflected on the upper surface 15 b of the prism 15.
The light is further reflected by the high reflection film 23 provided to the second photodetector 14. A part of the return light of the light beam directed to the second photodetector 14 passes through the semi-transmissive film 22 and is received by the second photodetector 14.

First and second photodetectors 13, 1
The return lights of the light beams respectively received by 4 are output to the signal processing circuit 5 as light reception signals. The signal processing circuit 5 generates a reproduction signal, a focus error signal, and a tracking error signal by performing arithmetic processing based on these light receiving signals.

Next, a case where a DVD is used as the optical disk 2 will be described with reference to FIGS. 6A and 6B.

When a drive voltage is supplied and an external signal is input to the system controller 8, the system controller 8 drives the spindle motor 3 to rotate, thereby rotating the optical disk 2 chucked by the spindle motor 3, and As shown in FIG. 6A, a light beam having a wavelength of about 650 nm is emitted from the second laser diode 19 provided in the integrated optical element 11 of the optical pickup device 4.

The light beam emitted from the second laser diode 19 is applied to the second optical path branching film 21 provided on the second inclined surface 15d of the prism 15. Part of the light beam applied to the second optical path branching film 21
Is reflected by the optical path branching film 21 and enters the objective lens 30.

The light beam incident on the objective lens 30 is condensed by the objective lens 30 and is focused and irradiated on the signal recording surface of the rotating optical disc 2. Optical disk 2
The return light of the light beam including the signal component reflected by the signal recording surface is again condensed by the objective lens 30 and travels to the integrated optical element 11.

The return light of the light beam directed toward the integrated optical element 11 is again irradiated on the second optical path branching film 21 provided on the second inclined surface 15d of the prism 15. A part of the return light of the light beam applied to the second optical path branching film 21 is the second light.
And enters the prism 15 from the second inclined surface 15d.

The return light of the light beam that has entered the prism 15 from the second inclined surface 15 d is refracted at the time of incidence and travels toward the second photodetector 14. The return light of the light beam toward the second photodetector 14 is partially
5 and the first and second photodetectors 1
The light passes through the semi-transmissive film 22 provided between 3 and 14, and another part is reflected by the semi-transmissive film 22.

The return light of the light beam transmitted through the semi-transmissive film 22 is received by the second photodetector 14, as shown in FIG. On the other hand, the return light of the light beam reflected by the semi-transmissive film 22 is reflected on the upper surface 15 b of the prism 15.
The light is further reflected by the high reflection film 23 provided on the substrate. Then, the return light of the light beam reflected by the high reflection film 23 is received by the first photodetector 13.

First and second photodetectors 13, 1
The return lights of the light beams respectively received by 4 are output to the signal processing circuit 5 as light reception signals. The signal processing circuit 5 generates a reproduction signal, a focus error signal, and a tracking error signal by performing arithmetic processing based on these light receiving signals.

Here, the focus error signal FCS1 obtained by receiving the return light of the light beam emitted from the first laser diode 17 by the first and second photodetectors 13 and 14, and the second laser diode A method of calculating a focus error signal FCS2 obtained by the first and second photodetectors 13 and 14 receiving the return light of the light beam emitted from 19 will be described.

The first and second photodetectors 1
As described above, the optical discs 3 and 14 are divided in a direction corresponding to the radial direction of the optical disc 2 such that each of the optical discs 3 has a plurality of sensor units. As shown in FIG. 7, the first photodetector 13 of the integrated optical element 11 of this example is divided into four parts in a direction corresponding to the radial direction of the optical disk 2, and the four sensor units a, b, c, and d are divided into four parts. Have. The second photodetector 14 is divided into four parts in a direction corresponding to the radial direction of the optical disk 2, and the four sensor units e, f, and
g and h.

The focus error signal FCS1 obtained by receiving the return light of the light beam emitted from the first laser diode 17 by the first and second photodetectors 13 and 14 is transmitted to each of the sensor units a and b. ,
The received light signals output by c, d and e, f, g, h are as, bs, cs, ds, es, fs, gs, hs, respectively.
Then, it is obtained by the following arithmetic expression.

FCS1 = ｛(as + ds) − (bs + c)
_{s)} - K 1 {(} es + hs) - (fs + gs)} where K ₁ is a semi-permeable semipermeable membrane 22 provided between the bottom surface 15a and the first and second photodetectors 13 and 14 of the prism 15 Is a coefficient for correcting the difference in the amount of received light between the first photodetector 13 and the second photodetector 14 due to the following equation. For example, when the transmittance of the semi-transmissive film 22 at a wavelength of 780 nm is 50%, K ₁ = 2. .

The focus error signal FCS2 obtained by receiving the return light of the light beam emitted from the second laser diode 19 by the first and second photodetectors 13 and 14 is obtained by the following equation. Can be

FCS2 = ｛(es + hs) − (fs + g)
_{s)} - K 2 {(} as + ds) - (bs + cs)} where K ₂ is a coefficient for correcting the difference in the received light amount of the first photo-detector 13 by a semipermeable semipermeable membrane 22 and the second photodetector 14 And, for example, a wavelength of 650
When the transmittance of the semi-transmissive film 22 in nm is 60%,
K ₁ = 2.5.

The focus error signals FCS1 and FCS2 generated as described above are output to the system controller 8 as described above. Then, the system controller 8 drives the focus / track servo mechanism 6 based on these signals to move the lens support member in the direction of coming and coming from the optical disk 2, thereby performing focusing control.

As shown in FIG. 8, the semi-transmissive film 22 includes a first optical thin film 22a located on the first photo detector 13 and a second optical thin film 22b located on the second photo detector 14. And may be composed of In this case, the first optical thin film 22a is the first optical thin film 22a.
Has a wavelength dependence such that it functions as a semi-transmissive film with respect to the light beam emitted from the laser diode 17 and functions as a highly transparent film with respect to the light beam emitted from the second laser diode 19. The second optical thin film 22b functions as a semi-transmissive film for a light beam emitted from the second laser diode 19, and the first laser diode 17
It is desirable to use an optical thin film having wavelength dependency so as to function as a highly transparent film for the light beam emitted from the light source.

For example, when the first laser diode 17 emits a light beam having a wavelength of 780 nm and the second laser diode 19 emits a light beam having a wavelength of 650 nm, the first optical thin film 22a and the second optical Thin film 22
By using an optical thin film having wavelength dependency as shown in FIG. 9 as b, the light receiving amounts of the first photodetector 13 and the second photodetector 14 can be made substantially equal.

That is, as the first optical thin film 22a,
When the wavelength of the light beam is 650 nm, almost 100% is transmitted, and when the wavelength is 780 nm, about 50% is transmitted and about 50%.
%, The optical thin film 22b is used as the second optical thin film 22b. When the wavelength of the light beam is 650 nm, the optical thin film transmits about 50%, reflects about 50%, and when the wavelength of the light beam is 780 nm, transmits almost 100%. Is used, the first photodetector 13 and the second photodetector 1
4 can be made substantially equal.

In the recording / reproducing apparatus 1, the semi-transmissive film 22 of the integrated optical element 11 is configured as described above, and the light receiving amounts of the first photo detector 13 and the second photo detector 14 are made equal to each other, thereby obtaining the focus error signal FCS1. And the coefficients K ₁ and K ₂ of the calculation formula for calculating FCS2 can be set to 1, so that the signal processing circuit 5 can be simplified, the return light can be used as much as the light receiving signal, and the SN ratio can be maximized. Can be improved.

As described above, the integrated optical element 11 according to the present invention includes the first and second laser diodes 17 and 19 for emitting light beams having different wavelengths, respectively.
Since the return light of each light beam is received by the first and second photodetectors 13 and 14, both the read signal and the control signal can be read from optical disks having different optimum wavelengths such as CD, CD-R and DVD. And the number of components such as connection terminals can be reduced. Therefore, the optical pickup device 4 including the integrated optical element 11 and the recording / reproducing device 1 including the optical pickup device 4 can be simplified in configuration and can be downsized as a whole. .

In the optical pickup device according to the present invention, a diffraction grating 31 is provided between the integrated optical element 11 and the objective lens 30 as shown in FIG. And a plurality of sub beams.

As described above, the optical pickup device is provided with the diffraction grating 31 between the integrated optical element 11 and the objective lens 30, and separates the light beam emitted from the integrated optical element 11 into a main beam and a plurality of sub-beams. Accordingly, a three-beam method for detecting a difference between return lights of two sub-beams, or a DPP method (Differential Push-Pulse method) for subtracting a coefficient multiple of a push-pull signal of two sub-beams from a push-pull signal of a main beam.
Pull) allows a tracking error signal to be obtained.

When the diffraction grating 31 is provided between the integrated optical element 11 and the objective lens 30 as described above, the return light of the main beam and the sub beam is further separated by the diffraction grating 31 and separated. When the reflected light beams interfere with each other, accurate reproduction signals and track error signals may not be obtained. Therefore, in such an optical pickup device, the third light receiving section 32 for obtaining the reproduction signal and the tracking error signal is provided, and the third light receiving section 32 is provided between the objective lens 30 and the diffraction grating 31.
A third optical path branching film 33 for reflecting the return light and irradiating the second light receiving section 32 with the first optical path branching film 33 is provided.
It is desirable that only the focus error signal be obtained from the second photodetectors 13 and 14.

As a method of obtaining a tracking error signal, the first and second photodetectors 13 and 14 of the integrated optical element 11 are added to a direction corresponding to the radial direction of the optical disk 2 so as to be applied to a recording track of the optical disk 2. Along the direction, a high-frequency signal is obtained from the sum of the received light signals output by the sensor units, and the sum of the received light signals output by the sensor units located on one diagonal line and the sensor unit located on the other diagonal line A diagonal difference signal is obtained from a difference from the sum of the received light signals output by the DUT, and a phase of the diagonal difference signal is detected with reference to a high-frequency signal.
etection).

In the optical pickup device shown in FIG. 10, the DPD method may be used as a method for obtaining a tracking error signal. As described above, if the DPD method is used, a tracking error signal can be appropriately obtained without providing the diffraction grating 31. Further, the light beam transmitted through the diffraction grating 31
When a tracking error signal is obtained by the method D, the tracking error signal is obtained using the third light receiving unit 32. In this case, the third light receiving section 32 may be divided into a direction corresponding to the radial direction of the optical disc 2 and a direction along the recording track of the optical disc 2.

Although the integrated optical element, optical pickup device, and recording / reproducing device for recording / reproducing a signal on / from a CD, CD-R, and DVD have been described above, the present invention applies to other optical recording media. It is needless to say that the present invention can be applied to an integrated optical element for recording / reproducing a signal, an optical pickup device, and a recording / reproducing device.

[0084]

The integrated optical element according to the present invention is provided with first and second light-emitting elements for emitting light beams of different wavelengths, respectively, and the first and second light-emitting elements return the light beams of the respective light beams together. Since the light is received by the light receiving element,
It is possible to cope with two types of optical discs having different standards such as CD, CD-R and DVD, and to reduce the number of components such as output terminals.

Further, the optical pickup device according to the present invention is provided with first and second light-emitting elements for emitting light beams of different wavelengths, respectively, and returns the first and second light beams of the respective light beams together. Since it has an integrated optical element that receives light with a light receiving element,
A read signal and a control signal can be read from two types of optical disks having different standards such as VD, the number of components can be reduced, and the size can be reduced.

Further, in the recording / reproducing apparatus according to the present invention, the optical pickup device is provided with first and second light emitting elements for emitting light beams of different wavelengths, respectively. Since an integrated optical element for receiving light by the first and second light receiving elements is provided, C
It is possible to play back two types of optical discs having different standards, such as D, CD-R and DVD, without impairing their playback characteristics, to reduce the number of components and to downsize.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a recording / reproducing apparatus according to the present invention.

FIG. 2 is a configuration diagram showing an optical pickup device according to the present invention.

FIG. 3 is a longitudinal sectional view showing an integrated optical element according to the present invention.

FIG. 4 is a longitudinal sectional view of a main part showing the integrated optical element.

5A and 5B are diagrams showing a state in which a light beam is emitted from a first light emitting element of the integrated optical element, FIG. 5A is a longitudinal sectional view of the integrated optical element, and FIG. FIG.

6A and 6B are diagrams showing a state in which a light beam is emitted from a second light emitting element of the integrated optical element, FIG. 6A is a longitudinal sectional view of the integrated optical element, and FIG. FIG.

FIG. 7 is a plan view of the integrated optical element.

FIG. 8 is a longitudinal sectional view of a main part showing another example of the integrated optical element according to the present invention.

FIG. 9 is a diagram showing the wavelength dependence of a first optical thin film and a second optical thin film constituting a semi-transmissive film of the integrated optical element.

FIG. 10 is a configuration diagram showing another example of the optical pickup device according to the present invention.

[Explanation of symbols]

1 recording / reproducing device, 2 optical disk, 3 spindle motor, 4 optical pickup device, 5 signal processing circuit,
6 focus / track servo mechanism, 8 system controller, 11 integrated optical element, 12 semiconductor substrate,
DESCRIPTION OF SYMBOLS 13 1st photodetector, 14 2nd photodetector, 15, prism, 17 1st laser diode, 19 2nd laser diode, 20 1st optical path branch film, 21 2nd optical path branch film, 22 semi-transmissive film ,
23 high reflection film,

Claims (7)

[Claims] A first light-emitting element provided on a substrate; and a first light-receiving element and a second light-receiving element provided between the first and second light-emitting elements and provided on the substrate. A first and a second surface parallel to each other, and a third light beam which is inclined with a predetermined inclination angle with respect to the first and the second surface and emitted from the first light emitting element. Face and first
And a fourth surface which is inclined at a predetermined inclination angle with respect to the second surface and irradiated with a light beam emitted from the second light emitting element, wherein the first surface has the first and the second surfaces. A prism provided on the substrate so as to face the second light receiving element; and a light beam provided on the third surface of the prism and emitted from the first light emitting element directed to the optical recording medium. First optical path branching means for reflecting and returning light from the optical recording medium to enter the prism; and provided on a fourth surface of the prism and emitted from the second light emitting element. A second optical path branching means for reflecting the light beam toward the optical recording medium and transmitting the return light from the optical recording medium to enter the prism; a first surface of the prism; And a second light receiving element. Integrated optical device comprising a semipermeable membrane which is, a high reflection film provided on the second surface of the prism. 2. The semi-transmissive film is located on the first light-receiving element, functions as a semi-transmissive film for a light beam emitted from the first light-emitting element, and includes a second light-emitting element. A first wavelength-dependent semi-transmissive film that functions as a highly transparent film for a light beam emitted from the element, and light that is located on the second light-receiving element and emitted from the second light-emitting element A second wavelength-dependent semi-transmissive film that functions as a semi-transmissive film for the light beam and functions as a high-transmittance film for the light beam emitted from the first light emitting element. The integrated optical element according to claim 1. 3. The first and second light receiving elements are respectively divided into a direction corresponding to a radial direction of the optical recording medium and a direction corresponding to a direction along a recording track so as to have a plurality of light receiving portions. 2. The integrated optical element according to claim 1, wherein a tracking error signal is detected based on return light from the optical recording medium received by the plurality of light receiving units. 4. An integrated optical element, and a light beam emitted from the integrated optical element is condensed and irradiated onto a signal recording surface of an optical recording medium, and return light from the optical recording medium is reflected by the integrated optical element. And an objective lens to be introduced into the element, wherein the integrated optical element comprises: a first and a second light emitting element provided on a substrate; A first and a second light receiving element, a first and a second plane parallel to each other, and a first and a second plane, which are inclined at a predetermined inclination angle with respect to the first and the second plane. A third surface to be irradiated with the emitted light beam;
And a fourth surface which is inclined at a predetermined inclination angle with respect to the second surface and irradiated with a light beam emitted from the second light emitting element, wherein the first surface has the first and the second surfaces. A prism provided on the substrate so as to face the second light receiving element; and a light beam provided on the third surface of the prism and emitted from the first light emitting element directed to the optical recording medium. First optical path branching means for reflecting and returning light from the optical recording medium to enter the prism; and provided on a fourth surface of the prism and emitted from the second light emitting element. A second optical path branching means for reflecting the light beam toward the optical recording medium and transmitting the return light from the optical recording medium to enter the prism; a first surface of the prism; And a second light receiving element. A semipermeable membrane that is, the optical pickup device characterized in that it comprises a high reflection film provided on the second surface of the prism. And a third light receiving element for receiving a part of the return light from the optical recording medium. A return light from the optical recording medium is provided between the integrated optical element and the objective lens. A third optical path branching means for reflecting a part of the light toward the third light receiving element and transmitting the remaining light to the integrated optical element is provided, between the integrated optical element and the third optical path branching means. Wherein diffraction means for separating a light beam emitted from the integrated optical element toward a signal recording surface of the optical recording medium into a main beam and a plurality of sub-beams is provided. 5. The optical pickup device according to 4. 6. An integrated optical element, and a light beam emitted from the integrated optical element is condensed and irradiated on a signal recording surface of an optical recording medium, and return light from the optical recording medium is reflected by the integrated optical element. An objective lens to be introduced into the element, a driving unit for driving the optical recording medium, an objective lens supporting unit for movably supporting the objective lens in two axial directions, and detection from light returned from the optical recording medium. A signal processing circuit for generating a reproduction signal and a control signal based on the received signal, and moving the objective lens support means in a radial direction of the optical recording medium or in a direction of coming into contact with or separating from the optical recording medium based on the control signal. A moving unit, wherein the integrated optical element is provided on the substrate so as to be located between the first and second light emitting elements and the first and second light emitting elements provided on the substrate. First and second light receiving elements, first and second surfaces parallel to each other, and a light beam inclined from the first and second surfaces at a predetermined inclination angle and emitted from the first light emitting element A third surface to be irradiated with
And a fourth surface which is inclined at a predetermined inclination angle with respect to the second surface and irradiated with a light beam emitted from the second light emitting element, wherein the first surface has the first and the second surfaces. A prism provided on the substrate so as to face the second light receiving element; and a light beam provided on the third surface of the prism and emitted from the first light emitting element directed to the optical recording medium. First optical path branching means for reflecting and returning light from the optical recording medium to enter the prism; and provided on a fourth surface of the prism and emitted from the second light emitting element. A second optical path branching means for reflecting the light beam toward the optical recording medium and transmitting the return light from the optical recording medium to enter the prism; a first surface of the prism; And a second light receiving element. And the semi-transmissive film which is a recording and reproducing apparatus, characterized in that it comprises a high reflection film provided on the second surface of the prism. 7. The signal processing circuit according to claim 1, wherein the signal processing circuit outputs the second light emitted from the first light emitting element based on a value based on a light reception signal emitted from the first light emitting element and received by the first light receiving element. By subtracting a constant multiple of the value based on the light receiving signal received by the light receiving element, or
From the value based on the light receiving signal emitted from the light emitting element and received by the second light receiving element, is a constant multiple of the value based on the light receiving signal emitted from the second light emitting element and received by the first light receiving element. 7. The recording / reproducing apparatus according to claim 6, wherein a focus control signal for performing control for moving the objective lens support member in a direction of coming into contact with and separating from the optical recording medium is generated by subtracting.