JP2004312046A - Semiconductor laser system and optical pickup system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it unlikely for a laser beam with a short-wavelength, to be misregistered from a predetermined position, and to make it less likely to be influenced by aberrations caused by optical elements, in a semiconductor laser system and an optical pickup system. <P>SOLUTION: A red outgoing beam from a semiconductor laser system 1 travels along a red-light optical axis 9, and an infrared outgoing beam travels along the infrared optical axis 10, that is almost parallel with the red-light optical axis 9, and is converted by a collimator lens 3 into parallel beams after transmitting a diffraction grating 2. Further, after passing through a beam splitter 4, these beams enter an object lens 5 and are condensed by the object lens 5 to an information recording medium 6. The red-light optical axis 9, i.e., the optical axis for the light having the shortest wavelength coincides with those of the collimator lens 3 and the objective lens 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical pickup device capable of reproducing or recording an optical recording medium having a different format such as a compact disk (CD) and a digital video disk (DVD), or a semiconductor laser device used for the optical pickup device.

  At present, a near-infrared semiconductor laser having a wavelength of 780 nm is used as a reproducing apparatus for a CD (compact disk). On the other hand, a red semiconductor laser having a shorter wavelength of 650 nm is used for recording / reproducing a DVD (digital video disk), which is an optical recording medium having a higher recording density, in order to reduce a light spot. Conventionally, for example, an optical pickup device described in Patent Literature 1 has been known as an optical pickup device capable of recording and reproducing two types of optical disks having different standards with one device. Hereinafter, this conventional optical pickup device will be described with reference to the drawings.

  As shown in FIG. 12, a conventional optical pickup device includes an integrated unit 101 which is a so-called semiconductor laser device having a laser diode mounted in a housing 116, a collimator lens 113, a 45 ° mirror 114, and an objective lens 115. Have been. The laser beams L1 and L2 emitted from the integrated unit 101 become parallel beams through a collimator lens 113, and the laser beams L1 and L2 are bent at a right angle by a 45 ° mirror 114, and are passed through an objective lens 115 to a disk surface (not shown). The integrated unit 101, the collimator lens 113, the 45 ° mirror 114, and the objective lens 115 are disposed so as to focus on the image. The return light from the disk surface passes through the objective lens 115, is bent at a right angle by the 45 ° mirror 114, and returns to the integrated unit 101 through the collimator lens 113.

As shown in FIG. 13, the internal structure of this integrated unit 101 is such that a laser diode 103 having a wavelength of 650 nm and a laser diode 104 having a wavelength of 780 nm are mounted via a LOP 108 on a photodiode IC 102 on which a photodetector 105 is formed. Further, a microprism 106 is mounted, and a hologram plate 107 is arranged on the microprism 106. The laser beams L1 and L2 are reflected by the microprism 106 and pass through the hologram plate 107, and the return light from the disk surface passes through the hologram plate 107, is diffracted, and enters the photodetector 105.
JP-A-11-149652

  Generally, with respect to an optical pickup device, the smaller the oscillation wavelength of the laser beam, the more easily the influence of aberrations related to optical components such as a lens and the smaller the spot size on the disk surface. Easier to receive.

  However, in the conventional integrated unit 101 shown in FIGS. 12 and 13, the arrangement relationship between the two laser diodes 103 and 104 having different emission wavelengths and the casing 116 is unknown, and Depending on the arrangement, for example, when assembling or adjusting the optical pickup device, the arrangement deviation or the optical axis deviation from a predetermined position is likely to occur particularly for laser light having a short wavelength. There has been a problem that the light spot is not connected.

  In the conventional optical pickup device shown in FIGS. 12 and 13, the arrangement relationship between the two laser diodes 103 and 104 having different emission wavelengths, the collimator lens 113 and the objective lens 115 is unknown. When the focal length is reduced by making the collimator lens 113 and the objective lens 115 smaller in order to realize a laser beam, depending on the arrangement of the two laser diodes 103 and 104, the laser light, particularly a laser beam having a short wavelength, may be used. Under the influence of the aberration of 115, problems such as the laser beam not being focused on the disk surface and the deformation of the light spot occur, and as a result, for example, information on the disk surface cannot be read correctly.

  In view of the above-described problems, the present invention provides a semiconductor laser device in which a short-wavelength laser light is less likely to be displaced from a predetermined position or an optical axis shift, and the short-wavelength laser light is caused by It is an object of the present invention to provide an optical pickup device which is less susceptible to the influence of the information and can correctly read the information on the disk surface.

  In order to solve the above problem, a semiconductor laser device of the present invention is a semiconductor laser device including at least two semiconductor laser elements having different oscillation wavelengths, a light receiving element, and an optical branching element, wherein the oscillation wavelengths are different. At least two semiconductor laser elements and a light-receiving element are arranged on a table placed in the same housing, and the table has a square shape when viewed from a direction perpendicular to an optical axis of light emitted from the semiconductor laser element. The semiconductor laser device is mounted on a side surface of the table, and the light receiving element is mounted on an upper surface of the table. At least two semiconductor laser devices having different oscillation wavelengths are integrated on one chip. A semiconductor laser array element, wherein the optical branching element is disposed as a cap on the upper part of the housing, and is formed of at least two semiconductor laser elements having different oscillation wavelengths. The light emission of a semiconductor laser device in which the optical axis of the emitted light is almost parallel at least up to the optical element arranged outside the housing, and whose oscillation wavelength is shortest when viewed from the direction of the optical axis emitted from the housing. A point is located at substantially the center of the housing, and return light branched from the return light emitted from at least two semiconductor laser elements having different oscillation wavelengths and reflected by the information recording medium is branched by the light branching element. Are directly incident on the light receiving element.

  With this configuration, since the light emitting point of the semiconductor laser element having the shortest oscillation wavelength is located substantially at the center of the housing, the optical axis of the shortest wavelength light source having the strictest assembly adjustment margin can be easily adjusted, and Since the optical axes of the light emitted from at least two semiconductor laser elements having different wavelengths are all substantially parallel, for example, the same condensing means can be used when configuring an optical pickup device.

  Preferably, the light splitting element is a hologram element, and the hologram surface and the upper surface of the light receiving element are parallel.

  According to the semiconductor laser device of the present invention, in such a configuration, when the housing is viewed from the direction of light emitted from at least two semiconductor laser elements having different oscillation wavelengths, the outer shape is formed by combining a rectangle and an arc. Accordingly, the rotation of the housing can be easily adjusted, and the rotation can be easily adjusted when the semiconductor laser device is incorporated in, for example, an optical pickup device.

  Another semiconductor laser device according to the present invention is a semiconductor laser including at least two semiconductor laser elements having different oscillation wavelengths, a light receiving element, a reflector that reflects light emitted from the semiconductor laser element, and a light splitting element. An apparatus, wherein at least two semiconductor laser elements having different oscillation wavelengths, a light receiving element, and the reflector are arranged in the same housing, and the at least two semiconductor laser elements having different oscillation wavelengths are integrated on one chip. The optical branching element is disposed as a cap on the upper part of the housing, and the optical axes of the light emitted from the at least two semiconductor laser elements having different oscillation wavelengths are all at least the housing. All are almost parallel up to the optical element arranged outside the body, and the reflector is moved from the direction of the optical axis emitted from the housing. Of the apparent light-emitting points of the semiconductor laser device viewed from above, the light-emitting point of the semiconductor laser device having the shortest oscillation wavelength is located substantially at the center of the housing, and at least two semiconductor lasers having different oscillation wavelengths Among the return light emitted from the element and reflected by the information recording medium, all the return light branched by the optical branching element enters the light receiving element.

  With this configuration, since the light emitting point of the semiconductor laser element having the shortest oscillation wavelength is located substantially at the center of the housing, the optical axis of the shortest wavelength light source having the strictest assembly adjustment margin can be easily adjusted, and Since the optical axes of the light emitted from at least two semiconductor laser elements having different wavelengths are all substantially parallel, for example, the same condensing means can be used when configuring an optical pickup device.

  The light receiving element is formed on a substrate, and the at least two semiconductor laser elements having different oscillation wavelengths are mounted on a bottom of a groove formed on the substrate, and the reflector is formed on one side surface of the groove. Is preferred.

  Another semiconductor laser device according to the present invention, having such a configuration, has a sliding portion in the housing, so that the rotation of the housing can be easily adjusted, so that the semiconductor laser device can be easily incorporated into an optical pickup device, for example. Rotation adjustment can be performed.

  Still another semiconductor laser device according to the present invention is a semiconductor including at least two semiconductor laser elements having different oscillation wavelengths, a light receiving element, a reflector that reflects light emitted from the semiconductor laser element, and a light branching element. A laser device, wherein the at least two semiconductor laser elements having different oscillation wavelengths, the light receiving element, the reflector, and the light branching element are disposed in a same housing, and the at least two semiconductor laser elements having different oscillation wavelengths are A semiconductor laser array element integrated on one chip, the casing is sealed, and a cap for transmitting light emitted from at least two semiconductor laser elements having different oscillation wavelengths is provided on the casing. The optical axes of light emitted from at least two semiconductor laser devices having different oscillation wavelengths are all disposed at least in the housing. Of the apparent emission points of the semiconductor laser element viewed through a reflector from the direction of the optical axis emitted from the casing, the oscillation wavelength is substantially parallel to all the optical elements arranged in the section. A light-emitting point for the shortest semiconductor laser element is located substantially at the center of the housing, and the light branching of return light emitted from at least two semiconductor laser elements having different oscillation wavelengths and reflected by an information recording medium is performed. Each of the return lights branched by the element enters the light receiving element.

  With this configuration, since the light emitting point of the semiconductor laser element having the shortest oscillation wavelength is located substantially at the center of the housing, the optical axis of the shortest wavelength light source having the strictest assembly adjustment margin can be easily adjusted, and Since the optical axes of the light emitted from at least two semiconductor laser elements having different wavelengths are all substantially parallel, for example, the same condensing means can be used when configuring an optical pickup device.

  It is preferable that the reflector and the light splitting element are configured by a common prism.

  More preferably, the cap doubles as a quarter-wave plate.

  In any of the semiconductor laser devices according to the present invention, at least two semiconductor laser elements having different oscillation wavelengths are integrated on one chip in such a configuration, so that the number of components can be reduced.

  In any of the semiconductor laser devices according to the present invention, each of the light emitting points of at least two semiconductor laser elements having different oscillation wavelengths falls within a circle having a diameter of 150 μm. The amount can be kept within 150 μm, and the influence of the displacement of the components can be minimized.

  In any of the semiconductor laser devices of the present invention, with such a configuration, the optical branching element is disposed on the housing, so that the inside of the housing can be sealed by the optical branching element, and the semiconductor mounted in the housing. The laser element and the like can be protected, and the reliability of the semiconductor laser element can be improved.

  In any of the semiconductor laser devices according to the present invention, the oscillation wavelength of the semiconductor laser element is any one of the 780 nm band, the 650 nm band, and the 400 nm band. It is possible to support reproduction or recording of an HD-DVD standard disc using a light source.

An optical pickup device of the present invention is an optical pickup device including any one of the semiconductor laser devices of the present invention described above, and an optical element that guides light emitted from the semiconductor laser device to an optical recording medium, wherein the plurality of semiconductor lasers are provided. The optical axis of the laser beam for the semiconductor laser element having the shortest oscillation wavelength among the laser elements passes substantially through the optical center of the optical element.

  With this configuration, since the optical axis of the laser light relating to the semiconductor laser element having the shortest oscillation wavelength passes substantially through the optical center of the optical element, the laser light having the shortest oscillation wavelength is less likely to be affected by the aberration due to the optical element. .

  According to the optical pickup device of the present invention, the optical axis of the light having the shortest oscillation wavelength out of the reflected light from the recording medium passes through substantially the optical center of the optical element so that the reflected light from the recording medium can be reduced. The one having the shortest oscillation wavelength can be made hard to be affected by the aberration by the optical element.

  Preferably, the optical element is a lens.

  According to the optical pickup device of the present invention, the oscillation wavelength of the semiconductor laser element is any one of the 780 nm band, the 650 nm band, and the 400 nm band. It is possible to support reproduction or recording of the HD-DVD standard disc to be used.

  As described above, according to the semiconductor laser device of the present invention, in the optical axis adjustment of the shortest wavelength light source having the strictest assembly adjustment margin, the shortest is obtained only by adjusting the center of the housing with respect to the optical axis of the condensing means. The light source of the wavelength can be automatically made coincident with the optical axis center of the optical pickup, thereby simplifying the assembling process.

  Further, according to the optical pickup device of the present invention, it is possible to prevent the laser beam having the shortest wavelength from being focused on the information recording medium, or to prevent the light spot from being deformed. Can read.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a configuration of an optical pickup device using a semiconductor laser device 1 of the present invention. When the information recording medium 6 is a DVD standard disk, the red emission light (wavelength 650 nm band) from the semiconductor laser device 1 passes through the diffraction grating 2 along the red optical axis 9 (dashed line), and then passes through the collimator lens 3. Is converted into a parallel light beam. Further, after passing through the beam splitter 4, the parallel light beam enters the objective lens 5 and is condensed on the information recording medium 6 by the objective lens 5. The reflected light from the information recording medium 6 follows the above-described path in reverse, is deflected by the beam splitter 4 and guided to the light receiving element 8 through the condenser lens 7, and the reproduced signal and various servo signals are detected. On the other hand, when the information recording medium 6 is a disc of the CD standard, the infrared emission light (wavelength 780 nm band) from the semiconductor laser device 1 follows the infrared light optical axis 10 (dotted line) substantially parallel to the red light optical axis 9. Incident on the diffraction grating 2 and is diffracted and split into a 0th-order diffracted light (main beam) and ± 1st-order diffracted light (sub-beam). Subsequently, the light is converted into a parallel light beam by the collimator lens 3, passes through the beam splitter 4, enters the objective lens 5, and is condensed on the information recording medium 6 by the objective lens 5. The reflected light from the information recording medium 6 follows the above-described path in reverse, is deflected by the beam splitter 4 and guided to the light receiving element 8 through the condenser lens 7, and the reproduced signal and various servo signals are detected.

  In this optical pickup device, the red light optical axis 9, that is, the optical axis for the light having the shortest wavelength coincides with the optical axes of the collimator lens 3 and the objective lens 5. That is, the red light optical axis 9 passes through the optical centers of the collimator lens 3 and the objective lens 5.

  Further, of the reflected light from the information recording medium 6, the optical axis of the red light coincides with the optical axes of the objective lens 5 and the condenser lens 7.

  With this configuration, the red light optical axis 9 of the semiconductor laser element having the shortest oscillation wavelength passes through the optical center of the collimator lens 3 and the objective lens 5, so that the red light is hardly affected by the aberration by the collimator lens 3 and the objective lens 5. Accordingly, it is possible to prevent the red light from being out of focus on the information recording medium 6 and to prevent the light spot of the red light from being deformed. As a result, the information on the information recording medium 6 can be correctly read. .

  Further, since the red light optical axis 9 and the infrared light optical axis 10 are substantially parallel, the red light and the infrared light should be used as the collimator lens 3, the objective lens 5, and the condenser lens 7 without distinction. Can be.

  Further, according to this configuration, of the reflected light from the recording medium, the red light optical axis 9 having the shortest oscillation wavelength passes through the optical centers of the objective lens 5 and the condensing lens 7 so that the reflected light from the information recording medium 6 Therefore, it is possible to reduce the influence of the aberration of the optical element with respect to the red light, so that the reflected light with respect to the red light can be reliably guided to the light receiving element 8 via the condenser lens 7.

  Hereinafter, the configuration of the semiconductor laser device 1 will be described in detail.

  FIG. 2 is a cross-sectional view of the semiconductor laser device 1, and FIG. 3 is a drawing of the semiconductor laser device 1 as viewed from the optical axis direction. A semiconductor laser array element 11 in which a semiconductor laser element capable of emitting red light and infrared light is formed on a single chip via a heat sink 12 is disposed inside the housing 14. Further, an APC (auto power control) light receiving element 15 for receiving the emitted light (backlight) 18 from the semiconductor laser array element 11 is arranged. Further, in the direction of the outgoing light (front light) 17 of the semiconductor laser array element 11, a cap 13 that transmits almost 100% of red light and infrared light is disposed. The reliability is ensured by sealing the light receiving element 11 with the light receiving element 15. The housing 14 has a terminal 16 for driving the semiconductor laser array element 11 and outputting a signal from the light receiving element 15. 1 and 2, the wiring between the semiconductor laser array element 11, the APC light receiving element 15 and the terminal 16 is not shown in order to avoid complexity.

  On the other hand, when the semiconductor laser device 1 is viewed from the optical axis direction of the outgoing light (front light) 17, the outermost shape is a circular arc as shown in FIG. , And the infrared light emitting point 20 is located at a distance of 150 μm or less. In FIG. 3, the intersection of two orthogonal dashed lines represents the center of the housing 14. This is the same for FIGS. 6, 8 and 11 described below.

  As described above, in the present embodiment, when the housing 14 is viewed from the optical axis direction, the light emitting point 19 of the red light which is the shortest wavelength light source used is located at the center of the housing 14, thereby assembling. In the optical axis adjustment of the shortest wavelength light source having the strictest adjustment margin, simply adjusting the center of the housing 14 with respect to the light condensing means, the shortest wavelength light source automatically matches the optical axis center of the optical pickup. This has the effect that the assembly process is further simplified. Further, when the housing 14 is viewed from the direction of the emitted light (front light), the outermost shape is circular, so that a rotation adjustment step is easily introduced when the semiconductor laser device 1 of the present embodiment is incorporated into the optical pickup device. It also has the effect that it can be done.

  In the present embodiment, the configuration using the infinite optical system using the collimator lens 3 has been described. However, the configuration is also applicable to a configuration using a finite optical system that does not use the collimator lens 3.

  Further, in the present embodiment, as the outer shape of the semiconductor laser device 1, a projection whose side is a surface obtained by cutting a part of a cylindrical surface may be formed, and the housing is viewed from the direction of light emitted from the semiconductor laser element. The outer shape at that time may be a shape formed by combining a rectangle and an arc. With such a configuration, the rotation of the housing can be easily adjusted.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIGS. Elements having the same functions as in the first embodiment are denoted by the same reference numerals.

  FIG. 4 is a diagram showing a configuration of an optical pickup device using the semiconductor laser device 1 of the present invention. When the information recording medium 6 is a DVD standard disk, the red emission light (wavelength 650 nm band) from the semiconductor laser device 1 enters the collimator lens 3 along the red light optical axis 9 and is converted into a parallel light beam. Further, the parallel light beam is converged on the information recording medium 6 by the objective lens 5. The reflected light from the information recording medium 6 follows the above-described path in reverse, and returns to the semiconductor laser device 1 as incident light. On the other hand, when the information recording medium 6 is a disc of the CD standard, the infrared emission light (wavelength 780 nm band) from the semiconductor laser device 1 is collimated along the infrared light optical axis 10 substantially parallel to the red light optical axis 9. 3 and is converted into a parallel light beam. Further, the parallel light beam is converged on the information recording medium 6 by the objective lens 5. The reflected light from the information recording medium 6 follows the above-described path in reverse, and returns to the semiconductor laser device 1 as incident light.

  In this optical pickup device, the red optical axis 9, that is, the optical axis for the light having the shortest wavelength, coincides with the optical axes of the collimator lens 3 and the objective lens 5. That is, the red light optical axis 9 passes through the optical center of the collimator lens 3 and the objective lens 5, the red light optical axis 9 and the infrared light optical axis 10 are substantially parallel, and the interval between them is 150 μm or less. That is, in the collimator lens 3 and the objective lens 5, the red optical axis 9 and the infrared optical axis 10 fall within a circle having a diameter of 150 μm.

  With this configuration, the influence of the aberration by the collimator lens 3 and the objective lens 5 on the red light and the infrared light can be suppressed to a minimum.

  Hereinafter, the configuration of the semiconductor laser device 1 will be described in detail.

  FIG. 5 is a cross-sectional view of the semiconductor laser device 1, and FIG. 6 is a drawing of the semiconductor laser device 1 viewed from the optical axis direction. A semiconductor laser array element 11 in which a semiconductor laser element capable of emitting red light and infrared light is formed on a single chip via a heat sink 12 is disposed inside the housing 14. Further, an APC (auto power control) light receiving element 15 for receiving the emitted light (backlight) 18 from the semiconductor laser array element 11 is arranged. Further, in the direction of the outgoing light (front light) 17 of the semiconductor laser array element 11, the diffraction grating 2 that generates 0-order diffracted light and ± 1st-order diffracted light with respect to infrared light, and return light from the information recording medium 6. A hologram element 23 in which a hologram 21 for diffracting or condensing the light 22 to the light receiving element 8 is integrated is arranged as a cap. The hologram element 23 and the housing 14 seal the semiconductor laser array element 11 and the light receiving elements 15 and 8 to ensure reliability. The light receiving element 8 receives the return light 22 diffracted or condensed by the hologram 21, and detects a reproduction signal and various servo signals. The housing 14 has terminals 16 for driving the semiconductor laser array element 11 and outputting APC signals, reproduction signals, and various servo signals from the light receiving elements 15 and 8. In FIG. 5, an Au wire or the like is usually used between the semiconductor laser array element 11, the light receiving element 8, the APC light receiving element 15 and the terminal 16, but their wiring is not shown in order to avoid complexity. .

  On the other hand, when the semiconductor laser device 1 is viewed from the optical axis direction of the outgoing light (front light) 17, the outermost shape is a combination of a rectangle and an arc as shown in FIG. Is located substantially at the center of the housing 14, and the emission point 20 of the infrared light is located at a distance of 150 μm or less.

  As described above, in the present embodiment, two semiconductor laser elements having different oscillation wavelengths are integrated in the same casing 14, and the light receiving element 8 for detecting a reproduction signal and various servo signals, and the optical branch By arranging and integrating the hologram element 23 as an element in the housing 14, there is an effect that the configuration of the optical pickup can be significantly reduced in size and thickness. Further, when the housing 14 is viewed from the optical axis direction, the light emitting point 19 of the red light, which is the shortest wavelength light source used, is located at the center of the housing 14, so that the light of the shortest wavelength light source having the strictest assembly adjustment margin is obtained. In the axis adjustment, only by adjusting the center of the housing 14 with respect to the light condensing means, the light source of the shortest wavelength automatically matches the optical axis center of the optical pickup, so that the assembling process is further simplified. Also have. When the housing 14 is viewed from the direction of the emitted light (front light) 17, the outermost shape is a combination of a rectangle and a circle, and the semiconductor laser device 1 of the present embodiment is incorporated in an optical pickup device. In some cases, the X and Y directions and the rotation are easily adjusted. Therefore, there is an effect that the optical pickup assembly adjustment process is simplified and the assembly yield is further improved.

(First Modification)
In addition, as a configuration of the semiconductor laser device, a configuration as shown in FIG. 7 may be used instead of the configuration as shown in FIG. Even when this configuration is used, the configuration of the optical pickup is exactly the same as that of FIG. 4 (the semiconductor laser device 1 of FIG. 4 may be replaced with the configuration of FIG. 7). In FIG. 7, an etching groove is formed on the silicon substrate 24 on which the light receiving element 8 is formed, as shown in a cross-sectional view showing the details around the semiconductor laser element in FIG. 9, and red light (650 nm wavelength band) is formed at the bottom. And a semiconductor laser array element 11 in which a semiconductor laser element capable of emitting infrared light (wavelength band of 780 nm) is integrated on one chip. A reflection mirror 28 is formed on one side surface of the etching groove, and light (front light) 17 emitted from the semiconductor laser array element 11 is reflected by the reflection mirror 28 and extracted to the upper part of the silicon substrate 24. The silicon substrate 24 is disposed inside the housing 14 having a sliding portion, and a hologram element 23 in which the diffraction grating 2 and the hologram 21 are integrated is disposed above the silicon substrate 24. That is, by sealing the silicon substrate 24 with the housing 14 and the hologram element 23, the silicon substrate 24 is protected and reliability is ensured. The housing 14 has a terminal 16 for driving the semiconductor laser array element 11 and outputting a signal from the light receiving element 8. In the operation of the semiconductor laser device, first, when the information recording medium 6 is a DVD standard disk, red light is emitted from the semiconductor laser device along the red light optical axis 9. The return light from the information recording medium 6 is diffracted / condensed by the hologram 21 in the semiconductor laser device shown in FIG. 7, the ± 1st-order diffracted light is guided to the light receiving element 8, and the reproduced signal and various servo signals are detected. On the other hand, when the information recording medium 6 is a CD standard disc, infrared light is incident on the diffraction grating 2 along an infrared light optical axis 10 substantially parallel to the red light optical axis 9, and the 0th-order diffracted light and ± 1st-order A folding light is generated. These lights pass through the hologram 21 and are emitted from the semiconductor laser device. The return light from the information recording medium 6 is diffracted / condensed by the hologram 21 in the semiconductor laser device shown in FIG. 7, the ± 1st-order diffracted light is guided to the light receiving element 8, and the reproduced signal and various servo signals are detected.

  On the other hand, when the semiconductor laser device of FIG. 7 is viewed from the optical axis direction of the emitted light (front light), the outermost shape is rectangular as shown in FIG. The point 26 is located substantially at the center of the housing 14, and the apparent emission point 27 of the infrared light via the reflection mirror 28 is located at a distance of 150 μm or less.

  Also in this configuration, as described with reference to FIGS. 4 to 6, two semiconductor laser elements having different oscillation wavelengths are integrated in the same casing 14, and a light receiving element 8 for detecting a reproduction signal and various servo signals is further provided. In addition, by arranging / integrating the hologram element 23, which is a light splitting element, in the housing 14, there is an effect that the configuration of the optical pickup can be significantly reduced in size and thickness. Further, when the housing 14 is viewed from the optical axis direction, the apparent light emitting point 26 of the red light, which is the shortest wavelength light source used, is located at the center of the housing 14, so that the shortest wavelength light source having the strictest assembly adjustment margin is provided. In the optical axis adjustment of the above, the light source of the shortest wavelength automatically matches the optical axis center of the optical pickup simply by adjusting the center of the housing 14 with respect to the condensing means, so that the assembling process is further simplified. It also has the effect. Further, the housing 14 is provided with a sliding portion 25 so that rotation adjustment during assembly adjustment can be easily performed. By performing rotation adjustment along the sliding portion 25, an apparent light emitting point of red light is obtained. Since the rotation of the semiconductor laser device can always be adjusted with 26 as the center of rotation, the optical axis can be adjusted very easily and easily. Therefore, the assembly yield is also improved.

(Second Modification)
Further, as the configuration of the semiconductor laser device, a configuration as shown in FIG. 10 may be used instead of the configuration as shown in FIG. Even when this configuration is used, the configuration of the optical pickup is exactly the same as that of FIG. 4 (the semiconductor laser device 1 of FIG. 4 may be replaced with the configuration of FIG. 10). In FIG. 10, one semiconductor laser device capable of emitting red light (wavelength band of 650 nm) and infrared light (wavelength band of 780 nm) via the heat sink 12 is mounted on a silicon substrate 24 on which the light receiving element 8 is formed. A semiconductor laser array element 11 integrated on a chip is mounted. Further, a prism 29 having a function of reflecting the emitted light (front light) 17 from the semiconductor laser array element 11 and reflecting the return light from the information recording medium 6 to guide the light to the light receiving element 8 is provided above the light receiving element 8. Is arranged. The silicon substrate 24 is disposed inside a housing 14 having a terminal 16 for driving the semiconductor laser array element 11 and outputting a signal from the light receiving element 8, and has a cap and ４ on its upper part. The wave plate 30 is arranged. That is, reliability is ensured by sealing the silicon substrate 24 with the housing 14 and the cap and quarter-wave plate 30. First, when the information recording medium 6 is a DVD standard disc, red light is emitted from the semiconductor laser array element 11, reflected by the prism 29, and transmitted through the cap and quarter-wave plate 30. Then, the light is emitted from the semiconductor laser device shown in FIG. The return light from the information recording medium 6 is refracted / incident on the prism 29 and is repeatedly reflected to be guided to the light receiving element 8, where a reproduction signal and various servo signals are detected. Here, the cap and quarter-wave plate are used to reduce the influence of return optical noise. On the other hand, when the information recording medium 6 is a CD standard disk, infrared light is emitted from the semiconductor laser array element 11, reflected by the prism 29, and transmitted through the cap and quarter-wave plate 30, and the semiconductor light shown in FIG. Emitted from the laser device. The return light from the information recording medium 6 is refracted / incident on the prism 29 and is repeatedly reflected to be guided to the light receiving element 8, where a reproduction signal and various servo signals are detected.

  On the other hand, when the semiconductor laser device of FIG. 10 is viewed from the optical axis direction of the outgoing light (front light), the outermost shape is rectangular as shown in FIG. 26 is located substantially at the center of the housing 14, and the apparent light emitting point 27 of the infrared light via the reflection mirror 28 is located at a distance of 150 μm or less.

  Also in this configuration, as described with reference to FIGS. 4 to 6, two semiconductor laser elements having different oscillation wavelengths are integrated in the same casing 14, and a light receiving element 8 for detecting a reproduction signal and various servo signals is further provided. Also, by arranging / integrating the prism 29 as a reflector and the cap and quarter-wave plate 30 in the housing 14, the configuration of the optical pickup can be significantly reduced in size and thickness. Have. Further, when the housing 14 is viewed from the optical axis direction, the apparent light emitting point 26 of the red light, which is the shortest wavelength light source used, is located at the center of the housing 14, so that the shortest wavelength light source having the strictest assembly adjustment margin is provided. In the optical axis adjustment of the above, the light source of the shortest wavelength automatically matches the optical axis center of the optical pickup simply by adjusting the center of the housing 14 with respect to the condensing means, so that the assembling process is further simplified. It also has the effect. Therefore, the assembly yield is also improved.

  Note that the application example described in the first embodiment can be similarly applied to the present embodiment.

  In the semiconductor laser device and the optical pickup device according to the above embodiment, one or two of the two semiconductor laser devices having an oscillation wavelength of 780 nm band, 650 nm band, or 400 nm band (390 nm to 420 nm) are used. In particular, if a semiconductor laser having a wavelength of 400 nm is used, an HD-DVD compatible optical recording medium can be recorded or reproduced.

  In the semiconductor laser device and the optical pickup device according to the above embodiment, three or more semiconductor laser elements may be mounted. In this case, if the emission point of each semiconductor laser element falls within a circle having a diameter of 150 μm, the shift amount of the optical axis emitted from each semiconductor laser element can be kept within 150 μm, and the displacement of the component parts can be reduced. The effect can be minimized. If the optical axis of each semiconductor laser element falls within a circle having a diameter of 150 μm, the deviation of the optical axis emitted from each semiconductor laser element can be kept within 150 μm, and the collimator lens 3 and the objective lens 5 Can minimize the influence of aberration.

  A semiconductor laser device and an optical pickup device according to the present invention are a semiconductor laser device and an optical pickup device capable of supporting reproduction or recording of a CD standard disk or a DVD standard disk, and an HD-DVD standard disk using a blue light source. Especially useful.

1 is a side view schematically showing an optical pickup device according to a first embodiment of the present invention. Sectional view of the semiconductor laser device Top view of the semiconductor laser device Side view schematically showing an optical pickup device according to Embodiment 2 of the present invention. Sectional view of the semiconductor laser device Top view of the semiconductor laser device Sectional view relating to a first modification of the semiconductor laser device. Top view related to a first modified example of the semiconductor laser device Sectional view showing details around a semiconductor laser element in a first modified example of the semiconductor laser device. Sectional view relating to a second modification of the semiconductor laser device. Top view related to a second modified example of the semiconductor laser device Schematic diagram of a conventional optical pickup device A perspective view schematically showing the optical pickup device.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Semiconductor laser device 2 Diffraction grating 3 Collimator lens 4 Beam splitter 5 Objective lens 6 Information recording medium 7 Condensing lens 8 Light receiving element 9 Red light optical axis 10 Infrared light optical axis 11 Semiconductor laser array element 12 Heat sink 13 Cap 14 Housing 15 Light receiving element 16 Terminal 17 Outgoing light (front light)
18 Outgoing light (backlight)
Reference Signs List 19 Red light emission point 20 Infrared light emission point 21 Hologram 22 Return light 23 Hologram element 24 Silicon substrate 25 Sliding part 26 Apparent light emission point of red light 27 Apparent light emission point of infrared light 28 Reflection mirror 29 Prism 30 cap and 1/4 wavelength plate

Claims (13)

A semiconductor laser device including at least two semiconductor laser elements having different oscillation wavelengths, a light receiving element, and an optical branching element,
At least two semiconductor laser elements and light receiving elements having different oscillation wavelengths are arranged on a table mounted in the same housing,
The table has a square shape when viewed from a direction perpendicular to the optical axis of light emitted from the semiconductor laser element,
The semiconductor laser element is mounted on a side surface of the table, and the light receiving element is mounted on an upper surface of the table, respectively.
At least two semiconductor laser devices having different oscillation wavelengths are semiconductor laser array devices integrated on one chip,
The light branching element is disposed as a cap on the upper part of the housing,
The optical axes of the light emitted from the at least two semiconductor laser elements having different oscillation wavelengths are all substantially parallel to at least the optical element arranged outside the housing, and the direction of the optical axis emitted from the housing. The emission point of the semiconductor laser device having the shortest oscillation wavelength as viewed from is located substantially at the center of the housing,
The return light emitted from at least two semiconductor laser elements having different oscillation wavelengths and reflected by the information recording medium, and the return light branched by the optical branching element is directly incident on the light receiving element. Semiconductor laser device. At least two semiconductor laser elements having different oscillation wavelengths, a light receiving element,
A reflector that reflects light emitted from the semiconductor laser element, and a semiconductor laser device including an optical branching element,
At least two semiconductor laser elements having different oscillation wavelengths, a light receiving element, and the reflector are arranged in the same casing,
At least two semiconductor laser elements having different oscillation wavelengths are configured as a semiconductor laser array element integrated on one chip,
The light branching element is disposed as a cap on the upper part of the housing,
The optical axes of the light emitted from the at least two semiconductor laser elements having different oscillation wavelengths are all substantially parallel at least up to the optical element disposed outside the housing, and the optical axis of the light emitted from the housing is Of the apparent light emitting points of the semiconductor laser element viewed from the direction through the reflector, the light emitting point of the semiconductor laser element having the shortest oscillation wavelength is located substantially at the center of the housing,
The return light branched by the light branching element among the return light emitted from at least two semiconductor laser elements having different oscillation wavelengths and reflected by the information recording medium is incident on the light receiving element. Semiconductor laser device. A semiconductor laser device including at least two semiconductor laser elements having different oscillation wavelengths, a light receiving element, a reflector that reflects light emitted from the semiconductor laser element, and an optical branch element,
At least two semiconductor laser elements and light-receiving elements and the reflector and the light branching element having different oscillation wavelengths are arranged in the same casing,
At least two semiconductor laser elements having different oscillation wavelengths are configured as a semiconductor laser array element integrated on one chip,
A cap that seals the casing and transmits light emitted from at least two semiconductor laser elements having different oscillation wavelengths is disposed on an upper portion of the casing,
The optical axes of the light emitted from the at least two semiconductor laser elements having different oscillation wavelengths are all substantially parallel at least up to the optical element disposed outside the housing, and the optical axis of the light emitted from the housing is Of the apparent light emitting points of the semiconductor laser element viewed from the direction through the reflector, the light emitting point of the semiconductor laser element having the shortest oscillation wavelength is located substantially at the center of the housing,
The return light branched by the light branching element among the return light emitted from at least two semiconductor laser elements having different oscillation wavelengths and reflected by the information recording medium is incident on the light receiving element. Semiconductor laser device. 2. The outer shape of the casing as viewed from the direction of light emitted from at least two semiconductor laser elements having different oscillation wavelengths is a shape formed by combining a rectangle and an arc. Semiconductor laser device. 2. The semiconductor laser device according to claim 1, wherein the light splitting element is a hologram element, and the hologram surface and an upper surface of the light receiving element are parallel. The light receiving element is formed on a substrate, and the at least two semiconductor laser elements having different oscillation wavelengths are mounted on a bottom of a groove formed on the substrate,
3. The semiconductor laser device according to claim 2, wherein said reflector is formed on one side surface of said groove. 7. The semiconductor laser device according to claim 6, wherein said housing has a sliding portion. 4. The semiconductor laser device according to claim 3, wherein the reflector and the light splitting element are configured by a common prism. 9. The semiconductor laser device according to claim 8, wherein the cap doubles as a quarter-wave plate. The semiconductor laser device according to claim 1, wherein respective light emitting points of at least two semiconductor laser elements having different oscillation wavelengths fall within a circle having a diameter of 150 μm. An optical pickup device comprising: the semiconductor laser device according to any one of claims 1 to 10; and an optical element that guides light emitted from the semiconductor laser device to an optical recording medium.
An optical pickup device in which an optical axis of a laser beam with respect to a semiconductor laser element having the shortest oscillation wavelength among the plurality of semiconductor laser elements passes substantially through an optical center of the optical element. 12. The optical pickup device according to claim 11, wherein an optical axis of light having the shortest oscillation wavelength of the light reflected from the optical recording medium passes substantially through an optical center of the optical element. 13. The optical pickup device according to claim 11, wherein the optical element is a lens.

Images