JP2001291259A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of converging an optical spot on an optical recording disk in an excellent state for all laser beams by correcting chromatic aberration, in an optical pickup device using laser beams of different wavelengths. SOLUTION: In the optical pickup device 1, since a second laser beam L2 has a longer wavelength compared with a first laser beam L1, a second laser beam source 12 is arranged more backward than a first laser beam source 11, by a distance L correcting that deviation of a focal position of a collimator lens 23 which is caused by chromatic aberration between the first and second laser beams L1, L2. In addition, as to the second laser beam source 12 arranged at a position off the optical axis center L0 of the collimator lens 23, the optical axis center L20 is set obliquely relative to the optical axis center L0 of the collimator lens 23, making the intensity center of the light quantity of the second laser beam L2 coincide with the center of a light flux L5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device using a plurality of laser light sources for emitting laser beams having different wavelengths. More specifically, the present invention relates to an arrangement structure of each laser light source.

[0002]

2. Description of the Related Art Conventionally, as an optical recording disk (optical recording medium), a CD (compact disk) having a thickness of 1.2 mm has been mainly used, but with the practical use of a red laser diode having a short wavelength. Thus, a DVD (digital versatile disk) having a thickness of 0.6 mm, which is about the same size as a CD and has a large capacity, is being commercialized. That is, since the size of the light spot formed on the disk surface of the optical recording medium is proportional to the square of the wavelength, a CD using a 780 nm infrared infrared AlGaAs laser diode is used.
Than 635/630 nm band red light AlG
A DVD using an aInP-based laser diode can realize high-density recording because the wavelength is shorter.

[0003] However, from the viewpoint of utilizing existing data, it is important that a DVD drive device can reproduce data from a CD optical recording disk (hereinafter, referred to as a CD disk). Here, the wavelength is 635
/ Nm band red laser light, by operating the aperture of the objective lens with respect to the optical recording disk to change the depth of focus, it is basically possible to record and play back DVD-based disks,
CD-based discs can be played. For example, DVD
In the case of a system disk, information is reproduced with NA = 0.6,
In the case of a D-system disc, information is reproduced with NA = 0.45. However, the red laser beam of 635/630 nm
Among D-type discs, it corresponds to the absorption band of the organic dye used for CD-R (write-once CD that can be rewritten only once),
With red laser light having a wavelength of 635/630 nm band, CD-
Reproduction of information from R is not possible.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 10-69670, one optical pickup device has
A first laser light source that emits a first laser light, and a second laser light source that emits a second laser light having a different wavelength from the first laser light.
Are formed on a common substrate, and the laser light emitted from these laser light sources is guided on a common optical path.

According to the optical pickup device having such a configuration, it is possible to reproduce a signal from a DVD using the first laser light having a short wavelength, and to reproduce a CD using the second laser light having a long wavelength. A signal can be reproduced from a system disk. Further, since the first laser light and the second laser light are guided on a common optical path, the objective lens and the photodetector can be shared. Therefore, in such an optical pickup device, the optical system can be simplified.

[0006]

However, when the collimating lenses are used in the optical pickup device using the two-wavelength laser light, the characteristics of the light emitted from the collimating lens due to the chromatic aberration of these laser lights. Therefore, there is a problem that the light spot cannot be converged on the optical recording disk in a favorable state for one of the laser beams.

In view of the above problems, an object of the present invention is to provide an optical pickup device using laser beams having different wavelengths, by correcting chromatic aberration according to the position of a laser light source, thereby improving the irrespective of any laser beam. It is an object of the present invention to provide a configuration capable of converging a light spot on an optical recording disk in a proper state.

[0008]

According to the present invention, at least a first laser light source for emitting a first laser light and a second laser light having a wavelength longer than the first laser light are provided. A second laser light source that emits the first laser light, and a first laser light that is emitted from the first and second laser light sources.
And a collimating lens into which the second laser light is incident, wherein the second laser light source is configured to output the first laser light and the second laser light in an optical axis direction to the collimating lens. The collimator lens is disposed behind the first laser light source by a distance capable of correcting a shift of a focal position of the collimator lens due to chromatic aberration.

Since the second laser light has a longer wavelength than the first laser light, if the first laser light source and the second laser light source are arranged at the same position in the optical axis direction of the collimating lens. In addition, the light spot cannot be converged in an excellent state on the optical recording medium due to a shift of the focal position of the collimator lens caused by the chromatic aberration between the first laser light and the second laser light. However, in the present invention, the second laser light source that emits the second laser light having a longer wavelength is disposed behind the first laser light source by a distance for correcting this deviation. For this reason, since the focal positions of the collimator lenses coincide in both the first and second laser beams, the collimator lens converts both the first and second laser beams into optimal parallel light beams. Therefore, both the first and second laser beams converge as a light spot in an excellent state on the optical recording medium.

In the present invention, of the first and second laser light sources, the laser light source disposed at a position deviated from the center of the optical axis of the collimating lens is the optical axis of the laser light emitted from the laser light source. It is preferable that the center is disposed so as to be inclined with respect to the center of the optical axis of the collimating lens. When two laser light sources are used, at least one of the laser light sources is disposed at a position off the optical axis center of the collimator lens. In such a case, if the centers of the optical axes of the two laser beams are made parallel, the intensity center of one of the laser beams deviates from the center of the light beam, and the objective lens moves following the track.
Depending on the moving direction, an imbalance occurs in the change in the amount of light, and the pickup characteristics deteriorate. However, according to the present invention, with respect to the laser light source disposed at a position deviated from the optical axis center of the collimating lens, the optical axis center of the laser light emitted from the laser light source is inclined with respect to the optical axis of the collimating lens. Since it is located in
The center of the intensity of the light amount of the laser beam can be made to coincide with the center of the light beam. Therefore, when the objective lens moves following the track, stable pickup characteristics can be obtained regardless of the moving direction.

In the present invention, the first and second laser light sources are, for example, semiconductor lasers formed on a common semiconductor substrate. With this configuration, high positional accuracy of the first laser light source and the second laser light source is ensured by a mask used in a semiconductor process when manufacturing these laser light sources. Therefore, the positions of the first laser light source and the second laser light source do not vary due to the assembly accuracy.

In the present invention, each of the first and second laser light sources may be a semiconductor laser formed on another semiconductor substrate.

In this case, it is preferable that the first and second laser light sources are mounted such that their polarization planes are substantially orthogonal to a common light source support plate. With this configuration, the degree of freedom in designing the reflection / transmission characteristics of the beam splitter used for polarization separation is increased, and the optical pickup can be manufactured with stable quality.

In the present invention, when the first and second laser light sources are mounted on a common light source support plate, for example, the first and second laser light sources may be mounted on a common light source support plate. The active layer is mounted on the opposite surface such that the active layer faces the opposite side of the support plate. With this configuration, since the first laser light source and the second laser light source are mounted with the light source support plate interposed therebetween, the interval between the emission optical axes can be reduced to approximately the thickness of the light source support plate. In addition, the dimensional accuracy of the interval is high. If a conductive light source support plate is used, the light source support plate can be used as a common cathode electrode by die-bonding the light source support plate with a junction.

In the present invention, the first and second laser light sources are arranged on the opposite surface of a common light source support plate.
A configuration may be adopted in which the active layers are respectively mounted so as to face the light source support plate. With this configuration, since the first laser light source and the second laser light source are mounted with the light source support plate interposed therebetween, the interval between the emission optical axes can be reduced to approximately the thickness of the light source support plate. In addition, the dimensional accuracy of the interval is high. Further, since the active layer is formed at a position shifted from the center in the thickness direction of the semiconductor laser, if the active layer is directed toward the light source support plate for both of the two laser light sources, the two laser light sources Between the light emitting points can be made as narrow as possible. Further, since the light emitting point is close to the light source support plate, there is an advantage that the heat radiation efficiency from the semiconductor laser to the light source support plate is improved.
Furthermore, if a conductive material is used as the light source support plate, the light source support plate can be used as a common anode electrode by die-bonding the light source support plate at a junction down.

In the present invention, the first and second laser light sources have a cross section H including a connecting plate portion and a pair of side plate portions extending in opposite directions from both sides of the connecting plate portion.
It is preferable that the common light source supporting plate is mounted on opposite surfaces of the connecting plate portion. In such a light source support plate, the light source support plate has an H-shaped cross section due to the side plate portion. Therefore, the connecting plate portion is formed to reduce the distance between the first laser light source and the second laser light source. Even when the light source support plate is made thin, the light source support plate has sufficient strength.

[0017]

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

[First Embodiment] FIG. 1 is a schematic configuration diagram showing an example of an optical pickup device according to a first embodiment of the present invention. FIG. 2 is an enlarged view showing the direction of the center of the optical axis of the laser light source arranged in the light source unit of the optical pickup device.

In FIG. 1, the optical pickup device 1 of the present embodiment has 635 nm (or 650 nm) and 780 nm.
Signals can be reproduced from both DVD and CD discs using a laser beam of nm.

More specifically, the optical pickup device 1 of this embodiment has a wavelength of 635 nm (or 650 nm).
m), a light source unit 10 for emitting the first laser light L1 and the second laser light L2 having a wavelength of 780 nm. The first and second laser beams L1 and L2 emitted from the light source unit 10 are guided to a DVD or CD system disk as the optical recording disk 2 (optical recording medium) via a common optical system 20. The return light L3 from the optical recording disk 2 is also guided to a common photodetector 21 (photodiode or phototransistor) via a common optical system 20.

The common optical system 20 includes a beam splitter 2 for guiding return light L3 from the optical recording disk 2 to the photodetector 21 for both the first and second laser beams L1 and L2.
2, a collimating lens 23 for converting the first and second laser beams L1 and L2 emitted from the beam splitter 22 into a parallel light beam, and applying the light emitted from the collimating lens 23 to the disk surface of the optical recording disk 2. And a converging objective lens 24.

The optical pickup device 1 configured as described above
In reproducing the signal from the DVD as the optical recording disk 2, the light source unit 10 outputs
A first laser beam L1 of 5 nm (or 650 nm) is emitted. The first laser light L1 emitted from the light source unit 10 passes through the beam splitter 22 and then enters the collimator lens 23. Collimating lens 23
The first laser light L1 incident on the collimator lens 2
3 converts the light beam into a substantially parallel light beam. The first laser beam L1 converted into a parallel light beam is converged by the objective lens 24 as a light spot on the DVD disk surface.

The return light L3 of the first laser light L1 reflected by the DVD disk surface is guided to the photodetector 21 through the common optical system 20. That is, the return light L3 from the DVD 2 passes through the objective lens 24 and the collimator lens 23, is reflected by the polarization reflection surface of the beam splitter 22, and is condensed on the photodetector 21. The light receiving signal detected by the light receiving surface of the photodetector 21 is subjected to signal reproduction processing by a control device (not shown).

On the other hand, as the optical recording disk 2, C
When reproducing a signal from a D-system disc, the light source unit 10 outputs a second laser beam L2 having a wavelength of 780 nm.
Is emitted. Similarly to the first laser light L1, the second laser light L2 emitted from the light source unit 10 also passes through the beam splitter 22, and then enters the collimator lens. The second laser light L2 incident on the collimator lens 23 is converted by the collimator lens 23 into a substantially parallel light beam. The second laser light L2 converted into a parallel light flux is converged by the objective lens 24 as a light spot on the disk surface of the CD.

The return light L3 of the second laser light L2 reflected on the disk surface of the CD disk is
0 and is guided to the photodetector 21, and a light-receiving signal detected on a light-receiving surface of the photodetector 21 is transmitted to a control device (not shown).
Performs a process for signal reproduction.

In the optical pickup device 1, the light source unit 10 has a wavelength of 635 nm (or 650 nm).
AlGaI that emits the first laser light L1 (red light)
First laser light source 1 composed of an nP-based laser diode
1 and a second laser light source 12 composed of an AlGaAs laser diode for emitting a second laser light L2 (infrared light) having a wavelength of 780 nm. These first
The second laser light source 11 and the second laser light source 12 are both mounted on a metal light source support plate 30, and the light source support plate 30 is fixed to a metal stem 36 in a common package 35. It is stored in.

In the present embodiment, the first laser light source 11 and the second laser light source 12 are semiconductor lasers formed on a common semiconductor substrate by a semiconductor process such as various crystal growth techniques or photolithography techniques. A semiconductor chip in which these two semiconductor lasers are integrally formed is mounted on the light source support plate 30.

In this embodiment, of the first and second laser light sources 11 and 12, the second laser light L2 having a longer wavelength is used.
Is disposed behind the first laser light source 11 by a distance corresponding to the distance L as the position of the emission end face in the direction of the optical axis center L0 of the collimating lens 23. I have. Here, the distance L is set to a value that corrects the shift of the focal position of the collimator lens 23 due to the chromatic aberration between the first laser light L1 and the second laser light L2.

Further, in the light source unit 10, as shown in an enlarged view in FIG.
2, the first laser light source 11 is disposed on the optical axis center L0 of the collimator lens 23, and the second laser light source 1
Reference numeral 2 is disposed at a position deviated from the optical axis center L0 of the collimating lens 23. Therefore, the second laser light source 12
As for the optical axis center L20 of the second laser light L0 emitted from the laser light source 12,
Are arranged obliquely with respect to the optical axis center L0. That is, the emission end face of the second laser light source 12 is inclined by the angle α with respect to the emission end face of the first laser light source 11.

The optical pickup device 1 configured as described above
, The second laser light L2 is the first laser light L1
Since the first laser light source 11 and the second laser light source 12 are arranged at the same distance in the optical axis direction of the collimator lens 23, the first laser light L1 and the second laser light The light spot cannot be converged on the optical recording disk 2 in a good state due to a shift of the focal position of the collimator lens 23 due to the chromatic aberration of the laser beam L2. However, in the present embodiment, the distance L for correcting this deviation is
However, the second laser light source 12 is disposed behind the first laser light source 11. Therefore, the collimating lens 2 is used for both the first and second laser beams L1 and L2.
3 are coincident with each other, the collimator lens 23
Converts both the first and second laser beams L1 and L2 into optimal parallel light beams. Therefore, both the first and second laser beams L1 and L2 converge on the optical recording disk 2 as light spots in a favorable state.

The first and second laser light sources 11,
Reference numeral 12 denotes a semiconductor laser formed on a common semiconductor substrate. Therefore, the first and second laser light sources 11,
Regarding 12, since a high positional accuracy is ensured by a mask used in a semiconductor process when manufacturing these laser light sources, the positions of the first and second laser light sources 11 and 12 may vary depending on assembly accuracy. Absent. Therefore, high accuracy can be ensured in the distance L between the light sources 11 and 12.

Further, in the optical pickup device 1,
When the configuration using two laser light sources 11 and 12 and guiding them to the common optical system 20 is adopted, at least one of the laser light sources is disposed at a position deviated from the optical axis center L0 of the collimator lens 23. You. In such a case, the optical axis centers L10, L of the two laser beams L1, L2
When the laser beam 20 is made parallel, the intensity center of one laser beam deviates from the center of the light beam, and when the objective lens moves following the track, an imbalance occurs in the change in the light amount depending on the moving direction. As a result, the pickup characteristics deteriorate. However, in this embodiment, the second collimator lens 23 is located at a position off the optical axis center L0.
Since the laser light source 12 is disposed so that the optical axis center L20 of the second laser light L2 emitted from the laser light source is oblique to the optical axis center L0 of the collimating lens 23, In the laser light L2, the intensity center of the light amount can be made to coincide with the center of the light beam L5. Therefore, when the objective lens 24 moves following the track, stable pickup characteristics can be obtained regardless of the moving direction.

The center L1 of the optical axis of the first laser beam L1
0 may be inclined obliquely with respect to the optical axis center L0 of the collimating lens 23.

[Second Embodiment] FIG. 3 is a schematic configuration diagram of a main part of an optical pickup device according to a second embodiment of the present invention. Note that, in this embodiment and any of the embodiments described later, the basic configuration as an optical pickup device is the same as that of the first embodiment, and the corresponding portions are denoted by the same reference numerals and description thereof. Is omitted.

In FIG. 3, similarly to the first embodiment, the optical pickup device 1 of the present embodiment emits a first laser beam L1 having a wavelength of 635 nm (or 650 nm) and a second laser beam L2 having a wavelength of 780 nm. It has a light source unit 10 for emitting light. The first and second laser beams L1 and L2 emitted from the light source unit 10 pass through a common optical system 20 to an optical recording disk (not shown) D.
Guided to a VD or CD disc. Further, return light from the optical recording disk 2 is also guided to a common photodetector 21 via a common optical system 20.

The light source unit 10 has a wavelength of 635.
a first laser light source 11 composed of a laser diode that emits a first laser light L1 (red light) having a wavelength of 780 nm (or 650 nm), and a second laser light L2 having a wavelength of 780 nm.
(Infrared light) and a second laser light source 12 composed of a laser diode. These first and second
Are mounted on a metal light source support plate 30 and housed in a common package 35.

In this embodiment, as in the first embodiment, of the first and second laser light sources 11 and 12, the second laser light source 12 that emits the second laser light L2 having a long wavelength has a chromatic aberration. Is disposed behind the first laser light source 10 by a distance L that corrects the shift of the focal position of the collimator lens 23 due to the above. For this reason, in this embodiment, after both the first and second laser beams L1 and L2 pass through the collimate lens 23, they are converted into good parallel light beams.

Also in this embodiment, as in the first embodiment,
Regarding the second laser light source 12 disposed at a position deviated from the optical axis center L0 of the collimating lens 23, the optical axis center L of the second laser light L2 emitted from this laser light source
Reference numeral 20 is disposed so as to be oblique with respect to the optical axis center L0 of the collimating lens 23. Therefore, as described with reference to FIGS. 1 and 2, the intensity center of the light amount of the second laser beam L2 can be made to coincide with the center of the light beam L5 emitted from the objective lens 24. Therefore, when the objective lens 24 moves following the track, stable pickup characteristics can be obtained regardless of the moving direction.

Further, in this embodiment, the first laser light source 1
Each of the first and second laser light sources 12 is a semiconductor laser formed on a separate semiconductor substrate. Here, since the first and second laser light sources 11 and 12 are mounted on respective surfaces adjacent to each other with respect to a common light source support plate 30, the first and second laser light sources 11 and 12 are The first and second laser beams L1 and L2 respectively emit laser beams whose polarization planes are substantially orthogonal to each other.

Therefore, in this embodiment, the degree of freedom in designing the reflection / transmission characteristics of the beam splitter 22 used for polarization separation is increased, and the optical pickup device 1 can be manufactured with stable quality. Such an effect is more remarkable as the difference between the wavelengths of the first laser light L1 and the second laser light L2 is larger.

Third Embodiment FIGS. 4A and 4B are plan views of the inside of a light source unit 10 used in an optical pickup device 1 according to a third embodiment of the present invention, as viewed from the light emitting side. FIG. 3 is a cross-sectional view of the inside of the light source unit as viewed from a second laser light source 12 side.

4A and 4B, even in the optical pickup device 1 of this embodiment, the light source unit 10
35 nm (or 650 nm) first laser light L1
A first laser light source 11 composed of a laser diode that emits (red light), and a second laser light source 12 composed of a laser diode that emits a second laser light L2 (infrared light) having a wavelength of 780 nm. are doing. These first and second laser light sources 11 and 12 are both mounted on a metal light source support plate 30 and have a common package 35.
Is housed inside.

Although not shown, in this embodiment, as described in the first embodiment, the first and second laser light sources 1
Of the first and second lasers 12 and 12, the second laser light source 12 that emits the second laser light L2 having a long wavelength has a first laser distance L for correcting a shift of the focal position of the collimator lens 23 due to chromatic aberration. It is arranged behind the light source 12. Therefore, the first and second laser beams L1, L2
Are transmitted through the collimate lens 23 and then converted into good parallel light beams.

In this embodiment, the first laser light source 11 and the second
The laser light sources 12 are semiconductor lasers formed on separate semiconductor substrates, respectively, and are mounted on a common light source support plate 30. The light source support plate 30 is
1 and a cross section H including a pair of side plate portions 32 and 33 extending in opposite directions from both sides of the connection plate portion 31 and standing upright.
And a first and second laser light source 1
Reference numerals 1 and 12 are mounted on the opposite surfaces of the connection plate portion 31 of the light source support plate 30, respectively. The first and second laser light sources 11 and 12 are connected to the connecting plate 3 of the light source support plate 30.
The active layers 110 and 120 are mounted on the connecting plate 31 so that the active layers 110 and 120 face the side opposite to the side of the first side. In addition, behind the first and second laser light sources 11 and 12, light receiving elements 41 and 42 for controlling the amount of light for receiving the laser light L25 emitted from the rear end face and monitoring the amount of emitted light are arranged. Have been.

The optical pickup device 1 configured as described above
, The first and second laser light sources 11 and 12 are respectively mounted on the surface of the common light source support plate 30 opposite to the connecting plate portion 31. For this reason, the first laser light source 1
The first active layer 110 and the active layer 12 of the second laser light source 12
The interval of 0 can be reduced to approximately the thickness of the light source support plate 30, and the dimensional accuracy of the interval is high.

The first and second laser light sources 11,
12 is mounted so that the active layers 110 and 120 face the opposite side of the connection plate portion 31 of the light source support plate 30, respectively, and since the light source support plate 30 is made of a conductive material, First and second laser light sources 11 and 12
Is die-bonded to the light source support plate 30 in a junction-up manner, so that the light source support plate 30 can be used as a common cathode electrode.

Further, the light source support plate 30 includes a side plate portion 32,
33, the light source support plate 30 is formed even when the connecting plate portion 31 is configured to be thin in order to reduce the distance between the first and second laser light sources 11 and 12.
Has sufficient strength.

Fourth Embodiment FIGS. 5A and 5B are plan views of the inside of a light source unit 10 used in an optical pickup device 1 according to a fourth embodiment of the present invention, as viewed from the light emitting side. FIG. 3 is a cross-sectional view of the inside of the light source unit as viewed from a second laser light source 12 side.

5A and 5B, in the optical pickup device 1 of this embodiment, the light source unit 10 has a wavelength of 6 nm.
35 nm (or 650 nm) first laser light L1
A first laser light source 11 composed of a laser diode that emits (red light), and a second laser light source 12 composed of a laser diode that emits a second laser light L2 (infrared light) having a wavelength of 780 nm. are doing. These first and second laser light sources 11 and 12 are both mounted on a metal light source support plate 30 and have a common package 35.
Is housed inside.

Although not shown, in this embodiment, as described in the first embodiment, the first and second laser light sources 1 are also used.
Of the first and second lasers 12 and 12, the second laser light source 12 that emits the second laser light L2 having a long wavelength has a first laser distance L for correcting a shift of the focal position of the collimator lens 23 due to chromatic aberration. It is arranged behind the light source 12. Therefore, the first and second laser beams L1, L2
Are transmitted through the collimate lens 23 and then converted into good parallel light beams.

In this embodiment, the first laser light source 11
And the second laser light source 12 are semiconductor lasers formed on separate semiconductor substrates, respectively, and are mounted on a common light source support plate 30. Also in the present embodiment, as in the third embodiment, the light source support plate 30
It has an H-shaped cross section including a pair of side plate portions 32, 33 extending in opposite directions from both sides of the connection plate portion 31, respectively, and is provided with first and second laser light sources 11, 12,
Are mounted on the surfaces of the light source support plate 30 on the opposite sides of the connection plate portion 31 respectively. Further, in the present embodiment, the first and second laser light sources 11 and 12 are mounted on the connection plate 31 so that the active layers 110 and 120 face the connection plate 31 of the light source support plate 30. In addition, behind the first and second laser light sources 11 and 12, light receiving elements 41 and 42 for controlling the amount of light for receiving the laser light L25 emitted from the rear end face and monitoring the amount of emitted light are arranged. Have been.

The optical pickup device 1 configured as described above
Since the first and second laser light sources 11 and 12 are respectively mounted on the surface of the common light source support plate 30 on the side opposite to the connecting plate portion 31, the active layer 110 and the first laser light source 11 The distance between the active layers 120 of the second laser light source 12 can be reduced to about the thickness of the light source support plate 30, and the dimensional accuracy of the distance is high.

Further, the first and second laser light sources 11,
Reference numeral 12 denotes the active layer 1 on the connection plate portion 31 of the light source support plate
Since the laser light sources 10 and 120 are mounted so as to face each other, the interval between the light emitting points between the two laser light sources 11 and 12 can be reduced as much as possible. That is, in the first and second laser light sources 11 and 12, the respective active layers 110 and 120 are formed at positions shifted from the center in the thickness direction of the chip to one side. When the active layers 110 and 120 are directed toward the connection plate portion 31 of the light source support plate 30, the distance between the active layers 110 and 120 between the first laser light source 11 and the second laser light source 12 is minimized. can do. Further, according to this structure, since the light emitting points of the semiconductor lasers 11 and 12 are close to the connecting plate portion 31 of the light source support plate 30, the heat radiation efficiency from the semiconductor lasers 11 and 12 to the light source support plate 30 is improved. is there.

In this embodiment, since the light source support plate 30 is made of a conductive material, the light source support plate 30 is electrically conductive.
Die bonding at junction down to
By insulating the light source support plate 30 from the stem 36 by the insulator 50, the light source support plate 30 can be used as a common anode electrode.

Further, the light source support plate 30 includes a side plate portion 32,
33, the light source support plate 30 is formed even when the connecting plate portion 31 is configured to be thin in order to reduce the distance between the first and second laser light sources 11 and 12.
Has sufficient strength.

[Other Embodiments] In the third and fourth embodiments, since the distance between the first laser light source 11 and the second laser light source 12 is small, the deviation of the emission optical axis of these laser light sources is caused. In some cases, the difference between the peak of the light amount distribution and the center of the light beam due to the above can be ignored. If such a difference cannot be ignored, one of the two surfaces of the connecting plate portion 31 of the light source support plate 30 is inclined. As described with reference to FIGS. 1 and 2, the laser light emitted from the laser light source disposed at a position deviated from the center of the optical axis of the collimator lens. By arranging the axis center so as to be oblique to the optical axis of the collimating lens, the first and second laser light sources 11 and
The center of the intensity of the light quantity distribution of No. 12 and the center of the light beam L5 may be matched.

In the above embodiment, the information is used for reproducing and recording information from optical recording disks having different thicknesses. However, the present invention is applied to an optical pickup device used for one type of optical recording disk drive. The invention may be applied. For example, a CD-R can sufficiently reflect near-infrared light having a wavelength of about 780 nm, but has little reflection and is absorbed in a visible region having a wavelength of about 650 nm. Therefore, recording can be performed with a small optical power by using the visible region around the wavelength of 650 nm. In this case, it is necessary to generate a light spot on the recording surface and simultaneously irradiate light having a wavelength that provides a sufficient reflectance for performing focus / tracking servo. Therefore, using an objective lens that has been subjected to aberration correction for condensing light of different wavelengths on the same recording surface, a laser light source having a longer wavelength is used when recording and reproducing by simultaneously turning on two laser light sources. By turning on, an optical pickup device capable of performing recording with a small optical power can be realized, and the present invention may be applied to such an apparatus.

Further, in the above-described second, third, and fourth embodiments, the laser light sources are formed as separate semiconductor chips, respectively. In this case, a laser light source is formed via a semiconductor substrate on which a light receiving element for controlling the amount of light is formed. The present invention may be applied to an optical pickup device having a configuration in which a laser light source is mounted on a light source support plate.

[0059]

As described above, in the optical pickup device according to the present invention, the second laser light source emits laser light having a longer wavelength than the first laser light source.
The first laser light source is disposed behind the first laser light source by a distance for correcting a shift of the focal position of the collimator lens due to chromatic aberration. For this reason, the focal positions of the collimating lenses coincide in both the first and second laser beams,
The collimating lens converts both the first and second laser beams into an optimal parallel light beam. Therefore, the first and second
Are converged as light spots on the optical recording medium in a favorable state.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of an optical pickup device according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged view showing a direction of a laser light source arranged in a light source unit of the optical pickup device shown in FIG.

FIG. 3 is a schematic configuration diagram of a main part of an optical pickup device according to a second embodiment of the present invention.

FIGS. 4A and 4B are plan views of a light source unit used in an optical pickup device according to Embodiment 3 of the present invention, as viewed from an emission side, and the inside of the light source unit is a second laser. It is sectional drawing seen from the light source side.

FIGS. 5A and 5B are plan views of a light source unit used in an optical pickup device according to Embodiment 4 of the present invention, as viewed from an emission side, and a second laser showing the inside of the light source unit. It is sectional drawing seen from the light source side.

[Explanation of symbols]

 Reference Signs List 1 optical pickup device 2 optical recording disk (optical recording medium) 10 light source unit 11 first laser light source 12 second laser light source 20 common optical system 21 photodetector 22 beam splitter 23 collimating lens 24 objective lens 30 metal Light source support plate 31 Connecting plate portion of light source support plate 32, 33 Side plate portion of light source support plate 35 Package 36 Stem 41, 42 Light receiving element for controlling light amount L Distance between first laser light source and second laser light source L0 Collimating lens L1 First laser light L2 Second laser light L3 Return light from optical recording disk L5 Light flux emitted from objective lens L10 Optical axis center of first laser light L20 Light of second laser light Axis center

Claims (8)

[Claims] At least a first laser light source that emits a first laser light, a second laser light source that emits a second laser light having a longer wavelength than the first laser light, and the first laser light source And a collimating lens on which the first and second laser lights emitted from the second laser light source enter, wherein the second laser light source is arranged in the optical axis direction of the collimating lens. The light is arranged behind the first laser light source by a distance capable of correcting a shift of a focal position of the collimating lens caused by chromatic aberration between the first laser light and the second laser light. Pickup device. 2. The method of claim 1, wherein the first and second
Of the laser light sources, the laser light source arranged at a position deviated from the optical axis center of the collimating lens is such that the optical axis center of the laser light emitted from the laser light source is oblique to the optical axis center of the collimating lens. An optical pickup device characterized by being arranged to be: 3. The optical pickup device according to claim 1, wherein the first and second laser light sources are semiconductor lasers formed on a common semiconductor substrate. 4. The optical pickup device according to claim 1, wherein the first and second laser light sources are semiconductor lasers formed on different semiconductor substrates, respectively. 5. The method according to claim 4, wherein
Wherein the laser light sources are mounted such that their polarization planes are substantially orthogonal to a common light source support plate. 6. The method according to claim 4, wherein
An optical pickup device, wherein the laser light sources are mounted such that the active layer is located on the opposite side to the side of the common light source support plate. . 7. The method according to claim 4, wherein
An optical pickup device, wherein the laser light sources are mounted such that the active layer is located on the side of the light source support plate on the surface opposite to the common light source support plate. 8. The method of claim 4, wherein the first and second
The laser light source is a common light source support plate having an H-shaped cross section including a connecting plate portion and a pair of side plate portions extending in opposite directions from both sides of the connecting plate portion, respectively, on opposite sides of the connecting plate portion. An optical pickup device mounted on a surface.