JP2012099655A - Laser unit and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser unit which improves thermal conductivity from a frame laser to a laser holder and positioning accuracy of the frame laser relative to the laser holder.SOLUTION: A laser unit 1 includes a frame laser 2, in which a semiconductor laser chip 22 is mounted on a surface 21a of a substrate 21 and a frame part 24 is integrally formed with the substrate 21 so as to enclose the semiconductor laser chip 22, and a laser holder 3 where an installation surface 31a, on which the frame laser 2 is placed, is provided. The frame laser 2 is placed so that a rear surface 21b of the substrate 21 contacts with the installation surface 31a. In the laser holder 3, a recessed part 31b is formed on the installation surface 31a and a resin part 4 is formed on the recessed part 31b with a filled resin.

Description

  The present invention relates to a laser unit including a frame laser on which a semiconductor laser chip is mounted, and to an electronic apparatus including such a laser unit.

  In general, an optical disk apparatus that records and reproduces information on an optical disk includes a semiconductor laser chip that irradiates the optical disk with a laser. In recent years, in order to increase the recording speed when information is recorded on an optical disk, the amount of heat generated by increasing the output of a semiconductor laser chip has increased. If the semiconductor laser chip heated to high temperature is continuously used, the light emission efficiency and life of the semiconductor laser chip may be deteriorated and reliability may be lowered. Therefore, in the optical disk device, it is required to increase the heat dissipation from the semiconductor laser chip.

  Further, if the position where the semiconductor laser chip is mounted is shifted, there is a problem that the optical axis of the irradiated laser is shifted. Therefore, a technique for fixing a semiconductor laser chip or a laser holder on which the semiconductor laser chip is mounted to an optical disk device has been studied (for example, see Patent Document 1).

  Currently, a CAN type semiconductor laser device is used in an optical disk device. In a CAN type semiconductor laser device, a semiconductor laser chip is mounted on a pedestal and sealed with a can-like container, and a glass window is provided on the laser emission surface. In an optical disk apparatus, since it is necessary to focus the laser on a minute point on the recording surface of the optical disk, the wavefront of the glass window that transmits the laser must be accurately aligned. The problem is that glass windows with small wavefront aberrations are expensive because they are difficult to manufacture.

  In recent years, a semiconductor laser device called a frame laser is sometimes used to reduce the cost of the optical disk device. Here, the frame laser is a product in which a semiconductor laser chip is mounted on a substrate and resin is outsert-molded on the substrate so as to surround the semiconductor laser chip, and does not have a glass window or a sealing structure. It is cheap.

  However, in the frame laser, there is a problem that dust easily adheres because the semiconductor laser chip is exposed to the outside. When dust adheres to the semiconductor laser chip, it has a great influence on the emitted laser, so it is important to protect the frame laser from dust. Therefore, a frame laser having a dustproof member that covers the semiconductor laser chip has been studied (for example, see Patent Document 2).

JP 2008-176890 A JP 2007-12138 A

  In the optical head described in Patent Document 1, the bottom surface of the laser holder is fixed to the housing with an adhesive. Accordingly, when fixing the laser holder, there is a possibility that the laser holder may be tilted by the adhesive, and there is a problem that the positioning accuracy of the semiconductor laser deteriorates.

  Further, the optical head device described in Patent Document 2 has a problem that it is expensive because a dustproof member is required.

  The present invention has been made to solve the above problems, and can improve the thermal conductivity from the frame laser to the laser holder, and can improve the positioning accuracy of the frame laser with respect to the laser holder. An object of the present invention is to provide a laser unit that can be used.

  It is another object of the present invention to provide an electronic device with improved reliability by including a laser unit with improved thermal conductivity and positioning accuracy.

  A laser unit according to the present invention includes a frame laser in which a semiconductor laser chip is mounted on a surface of a substrate and a frame portion is integrally formed on the substrate so as to surround the semiconductor laser chip, and an installation in which the frame laser is mounted. A laser unit provided with a surface, wherein the frame laser is mounted so that the back surface of the substrate and the installation surface are in contact with each other, and the laser holder has a recess formed on the installation surface In the recess, a resin portion is formed of a filled resin.

  According to this configuration, the thermal conductivity from the frame laser to the laser holder can be improved by bringing the back surface of the substrate into close contact with the installation surface. Moreover, the positioning accuracy of the frame laser with respect to the laser holder can be improved by suppressing the tilt when mounting the frame laser.

  In the laser unit according to the present invention, the laser holder includes a resin filling port applied to filling the resin into the concave portion.

  According to this configuration, since the resin can be filled after the frame laser is placed on the laser holder, the positioning accuracy can be further improved.

  In the laser unit according to the present invention, the resin portion is formed of a heat radiating resin, and the semiconductor laser chip and the resin portion are arranged at positions facing each other with the substrate interposed therebetween. .

  According to this configuration, the thermal conductivity can be further improved by disposing the resin portion formed of the heat radiating resin at a position close to the semiconductor laser chip.

  In the laser unit according to the present invention, the laser holder includes a dustproof portion provided on a surface side of the substrate, and the dustproof portion is formed so as to cover the semiconductor laser chip.

  According to this configuration, dust can be prevented from adhering to the semiconductor laser chip by covering the semiconductor laser chip with the dustproof portion.

  An electronic apparatus according to the present invention includes the laser unit according to the present invention.

  According to this configuration, by providing the laser unit with improved thermal conductivity and positioning accuracy, an electronic device with improved reliability can be provided.

  According to the present invention, the thermal conductivity from the frame laser to the laser holder can be improved by bringing the back surface of the substrate into close contact with the installation surface. Moreover, the positioning accuracy of the frame laser with respect to the laser holder can be improved by suppressing the tilt when mounting the frame laser.

  In addition, according to the present invention, it is possible to provide an electronic apparatus with improved reliability by including a laser unit with improved thermal conductivity and positioning accuracy.

It is a perspective view which shows the frame laser of the laser unit which concerns on embodiment of this invention. It is a perspective view from the diagonal front which shows the laser holder of the laser unit which concerns on embodiment of this invention. It is a perspective view from the slanting back which shows the laser holder of the laser unit which concerns on embodiment of this invention. It is a front view which shows schematic structure of the laser unit which concerns on embodiment of this invention. It is sectional drawing in the arrow AA of FIG. 3A. It is sectional drawing in the arrow BB of FIG. 3A. It is a perspective view from the diagonal front which shows the laser unit which concerns on embodiment of this invention. It is a perspective view from diagonally backward which shows the laser unit which concerns on embodiment of this invention. It is a schematic sectional drawing which shows the process of filling a recessed part with resin. It is a perspective view from diagonally backward which shows the modification of a laser holder. It is sectional drawing in the arrow CC of FIG. 6A. It is sectional drawing of the laser unit to which the modification of a laser holder is applied. It is a schematic block diagram which shows a laser integrated unit provided with the laser unit which concerns on embodiment of this invention. It is explanatory drawing which shows the structure of the optical system of the laser integrated unit shown in FIG.

  The laser unit according to the embodiment of the present invention has a configuration in which a frame laser is combined with a laser holder. In the following, first, each of the frame laser and the laser holder will be described based on the drawings, and then a laser unit in which the frame laser and the laser holder are combined will be described.

  FIG. 1 is a perspective view showing a frame laser of a laser unit according to an embodiment of the present invention.

  In the frame laser 2, a semiconductor laser chip 22 is mounted on a surface 21 a of a substrate 21 via a submount 23, and a frame portion 24 is integrally formed on the substrate 21 so as to surround the semiconductor laser chip 22.

  The semiconductor laser chip 22 is a laser diode that emits red and infrared lasers, and is arranged so that the end surface on the emission side is closer to the end portion (the emission end portion 21 c) of the substrate 21. Note that the present invention is not limited to this, and for example, a laser diode that emits a blue laser beam may be used.

  In the following, for explanation, the direction in which the laser is emitted from the semiconductor laser chip 22 is referred to as an emission direction X, the thickness direction of the substrate 21 is referred to as a height direction Z, and is orthogonal to the emission direction X and the height direction Z. This direction is called the width direction Y. Further, in the height direction Z, the front surface 21a side with respect to the substrate 21 may be referred to as the upper side, and the back surface 21b side with respect to the substrate 21 may be referred to as the lower side.

  The substrate 21 is a square lead frame made of metal, and is provided with an extension 25 that protrudes from both side surfaces in the width direction Y. The extension 25 is formed with a frame locking surface 25a perpendicular to the emission direction X and a frame positioning surface 25b perpendicular to the width direction Y. Moreover, in this Embodiment, although the board | substrate 21 is formed with the copper (Cu) alloy which gave silver (Ag) plating, this invention is not limited to this.

  Further, the substrate 21 is provided with a pin terminal 26 on the opposite side of the emission end portion 21c in the emission direction X, and the pin terminal 26 is used to connect the laser unit 1 and the outside. In the emission direction X, the emission end 21c side with respect to the substrate 21 may be referred to as the front, and the pin terminal 26 side with respect to the substrate 21 may be referred to as the rear. The back surface 21b of the substrate 21 is uniformly flat.

  The frame portion 24 is integrally formed with resin on the front surface 21 a and the side surface of the substrate 21, and protects the semiconductor laser chip 22 and the pin terminal 26. The frame portion 24 is formed so as to be higher than the semiconductor laser chip 22 in the height direction Z. Note that the frame portion 24 is not formed on the emission end portion 21 c (in front of the semiconductor laser chip 22) and above the semiconductor laser chip 22.

  2A is a perspective view from an oblique front showing the laser holder of the laser unit according to the embodiment of the present invention, and FIG. 2B is an oblique rear view showing the laser holder of the laser unit according to the embodiment of the present invention. FIG.

  The laser holder 3 is a holder for fixing the frame laser 2 to a laser integrated unit 6 (see FIG. 8) described later. The laser holder 3 includes a placement part 31, a connection part 32, and a dustproof part 33.

  The placement unit 31 is provided with an installation surface 31a parallel to the back surface 21b of the substrate 21, and a recess 31b lower than the installation surface 31a is formed in a part of the installation surface 31a. That is, when the board | substrate 21 is mounted in the installation surface 31a, a clearance gap is made between the recessed part 31b and the back surface 21b. Further, the mounting portion 31 is provided with a groove-shaped resin filling port 31c connected to the concave portion 31b from the rear. Details of the resin filling port 31c will be described later with reference to FIG.

  The dustproof unit 33 is disposed above the placement unit 31. Details of the dustproof portion 33 will be described later with reference to FIGS. 3A to 3C.

  The connecting portion 32 is formed so as to connect the front end portion of the mounting portion 31 and the front end portion of the dustproof portion 33, and includes an emission port 32 a through which the laser emitted from the semiconductor laser chip 22 passes. A holder locking surface 32 b perpendicular to the emission direction X is formed on the inner side surface of the coupling portion 32 in order to position the frame laser 2. Further, the connecting portion 32 is provided with an adhesive portion 32 c that contacts the surface 21 a of the substrate 21 and / or the frame portion 24.

  A holder positioning surface 34 perpendicular to the width direction Y is provided on the side surface of the laser holder 3.

  3A is a front view showing a schematic configuration of the laser unit according to the embodiment of the present invention, FIG. 3B is a cross-sectional view taken along arrow AA in FIG. 3A, and FIG. It is sectional drawing in the arrow BB. FIG. 4A is a perspective view from an oblique front showing a laser unit according to an embodiment of the present invention, and FIG. 4B is a perspective view from an oblique rear showing a laser unit according to an embodiment of the present invention.

  The laser unit 1 according to the embodiment of the present invention includes a frame laser 2 in which a semiconductor laser chip 22 is mounted on a surface 21 a of a substrate 21 and a frame portion 24 is integrally formed on the substrate 21 so as to surround the semiconductor laser chip 22. And a laser holder 3 provided with an installation surface 31a on which the frame laser 2 is placed. The frame laser 2 is placed so that the back surface 21b of the substrate 21 and the installation surface 31a are in contact with each other, and the laser holder 3 has a recess 31b formed in the installation surface 31a, and the recess 31b is made of a filled resin. Resin portion 4 is formed.

  According to this configuration, the thermal conductivity from the frame laser 2 to the laser holder 3 can be improved by bringing the back surface 21b of the substrate 21 into close contact with the installation surface 31a. Moreover, the positioning accuracy of the frame laser 2 with respect to the laser holder 3 can be improved by suppressing the tilt when the frame laser 2 is placed.

  In the laser unit 1, a frame laser 2 is inserted from the rear of the laser holder 3 toward the front. Here, the frame locking surface 25a and the holder locking surface 32b that are parallel to each other come into contact with each other, thereby positioning the frame laser 2 with respect to the laser holder 3 in the emission direction X. Further, by aligning the positions of the frame positioning surface 25b and the holder positioning surface 34 in the width direction Y, the frame laser 2 is positioned in the width direction Y with respect to the laser holder 3.

  When positioning the frame laser 2, the frame laser 2 can be reliably fixed to the laser holder 3 by applying an adhesive to the bonding portion 32 c.

  The dustproof portion 33 described above is configured to be positioned above the semiconductor laser chip 22 when the laser holder 3 and the frame laser 2 are combined. Further, it is desirable that the dustproof portion 33 is larger than the semiconductor laser chip 22 in plan view.

  As described above, the laser holder 3 includes the dustproof portion 33 provided on the surface 21 a side of the substrate 21. The dustproof part 33 is formed so as to cover the semiconductor laser chip 22. According to this configuration, dust can be prevented from adhering to the semiconductor laser chip 22 by covering the semiconductor laser chip 22 with the dustproof portion 33.

  As described above, the laser holder 3 includes the resin filling port 31c applied to filling the resin into the recess 31b. According to this configuration, since the resin can be filled after the frame laser 2 is placed on the laser holder 3, the positioning accuracy can be further improved.

  In the present embodiment, the resin portion 4 is formed of a heat-dissipating resin, and the semiconductor laser chip 22 and the resin portion 4 are disposed at positions facing each other with the substrate 21 interposed therebetween. According to this configuration, the thermal conductivity can be further improved by disposing the resin portion 4 formed of the heat radiating resin at a position close to the semiconductor laser chip 22. That is, the recess 31 b is formed at a position below the semiconductor laser chip 22, and the heat generated in the semiconductor laser chip 22 is transmitted to the laser holder 3 through the heat radiating resin having excellent thermal conductivity.

The heat radiation resin is mainly composed of a heat conductive resin such as olefin resin, PPS (Polyphenylene Sulfide) resin, polyamide (Polyamide) resin, silicon resin, or epoxy resin, and is made of silver (Ag) or the like. A filler made of metal, ceramics such as aluminum oxide (Al ₂ O ₃ ) or aluminum nitride (AlN), carbon fiber, or glass is contained. The thermal conductivity of the heat radiation resin is, for example, 3 [W / mK] when the main component is an olefin resin and the filler is aluminum oxide (Al ₂ O ₃ ).

  In addition, this invention is not limited to this, For example, you may fill the resin part 4 with adhesive agents, such as an ultraviolet curable resin and a thermosetting resin. By curing and shrinking the adhesive, the resin portion 4 for fixing the frame laser 2 and the laser holder 3 can be formed.

  FIG. 5 is a schematic cross-sectional view showing a process of filling the recess with resin.

  When filling the recess 31 b with resin, the frame laser 2 is placed and positioned on the laser holder 3. By providing the groove-shaped resin filling port 31c, a gap is formed between the back surface 21b of the substrate 21 and the installation surface 31a so as to connect to the recess 31b. The resin is injected into the recess 31b from the nozzle 5 inserted into the resin filling port 31c. When filling the resin, it is desirable to press the frame laser 2 against the laser holder 3 from above.

  6A is a perspective view from a diagonally rear side showing a modified example of the laser holder, and FIG. 6B is a cross-sectional view taken along arrows CC in FIG. 6A. FIG. 7 is a cross-sectional view of a laser unit to which a modification of the laser holder is applied.

  In the modification, the resin filling port 31c (through hole) is formed so as to be connected to the recess 31b from below. Even with this configuration, the resin can be filled after the frame laser 2 is placed on the laser holder 3.

  FIG. 8 is a schematic configuration diagram showing a laser integrated unit including the laser unit according to the embodiment of the present invention.

  The electronic apparatus according to the embodiment of the present invention includes a laser unit 1. According to this configuration, by providing the laser unit 1 with improved thermal conductivity and positioning accuracy, an electronic device with improved reliability can be provided.

  The electronic device is, for example, a three-wavelength optical pickup device. The three-wavelength optical pickup device performs recording / reproduction of optical disks such as BD, DVD, and CD.

  The laser integrated unit 6 is applied to, for example, the above-described three-wavelength optical pickup device and the like. The first laser unit 1a that irradiates red and infrared lasers and the second laser unit 1b that irradiates blue light lasers. And each laser is switched and emitted from an emission window (not shown).

  The laser integrated unit 6 includes a dichroic beam splitter 61 that reflects light of a specific wavelength and transmits light of other wavelengths. Note that what wavelength is reflected by the dichroic beam splitter 61 may be appropriately selected depending on the wavelength of the laser emitted from the first laser unit 1a and the second laser unit 1b. The relationship between the laser irradiated from the first laser unit 1a and the second laser unit 1b and the dichroic beam splitter 61 will be described in detail with reference to FIG.

  FIG. 9 is an explanatory diagram showing the configuration of the optical system of the laser integrated unit shown in FIG.

  The red laser La emitted from the first laser unit 1 a passes through the dichroic beam splitter 61 and is emitted from the laser integrated unit 6. The blue laser Lb emitted from the second laser unit 1b is reflected by the dichroic beam splitter 61, guided in the same direction as the red laser La, and emitted from the laser integrated unit 6.

DESCRIPTION OF SYMBOLS 1 Laser unit 2 Frame laser 21 Board | substrate 21a Front surface 21b Back surface 22 Semiconductor laser chip 23 Submount 24 Frame part 25 Extension part 26 Terminal pin 3 Laser holder 31 Mounting part 31a Installation surface 31b Recessed part 31c Resin filling port 32 Connection part 32c Adhesive part 33 Dust proof part 4 Resin part 6 Laser integrated unit (an example of electronic equipment)

Claims (5)

A semiconductor laser chip is mounted on the surface of the substrate, a frame laser in which a frame portion is integrally formed on the substrate so as to surround the semiconductor laser chip, and a laser holder provided with an installation surface on which the frame laser is mounted A laser unit comprising:
The frame laser is placed so that the back surface of the substrate and the installation surface are in contact with each other,
The laser holder has a recess formed on the installation surface,
The laser unit is characterized in that a resin portion is formed of a filled resin in the recess. The laser unit according to claim 1,
The laser unit is provided with a resin filling port applied to filling the concave portion with resin. The laser unit according to claim 1 or 2,
The resin part is made of heat dissipation resin,
The laser unit, wherein the semiconductor laser chip and the resin portion are arranged to face each other with the substrate interposed therebetween. The laser unit according to any one of claims 1 to 3, wherein
The laser holder includes a dustproof portion provided on the surface side of the substrate,
The dust unit is formed so as to cover the semiconductor laser chip.   An electronic apparatus comprising the laser unit according to any one of claims 1 to 4.

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