JPH0720935Y2 - Semiconductor laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a semiconductor laser device used for an optical head or the like.

[Prior Art] Recently, in an optical head of an optical information recording / reproducing apparatus, a high frequency superposition module (hereinafter referred to as HFM) is used for noise reduction of an LD (laser diode) which is a semiconductor laser light source. In the semiconductor laser device having such a configuration, when the LD and the HFM are separately configured, electromagnetic waves (500 to 900 MH) emitted from the lead portion of the LD and the HFM are generated.
There is a problem that z) leaks from the gap of the LD mounting part etc.
There is a problem that the standard of electromagnetic wave regulation such as CCi cannot be satisfied.

Japanese Utility Model Application Laid-Open No. 60-92855 was devised in view of the above problems. In the technique described in this publication, as shown in FIG. 3, a light output stabilizing circuit 1 and a high frequency superimposing circuit 2 are housed in the same shield case 3, and a semiconductor laser 4 and a photodetector 5 are built in. The package 6 is in close contact with the shield case 3. According to this structure, the electromagnetic waves radiated from the high frequency superposition circuit (HFM) 2 can be effectively shielded.

[Problems to be Solved by the Invention] Therefore, the above-mentioned conventional technique has the following problems.

(1) Since two shield cases 3 and 6 (specifically, reference numeral 6 is a metal package) are required, the shield case portion is complicated and large, resulting in high cost and poor workability during assembly.

(2) Since the large-scale shield case 3 is required, space efficiency is extremely poor.

(3) Although the electromagnetic wave radiated from the high frequency superposition circuit (HFM) 2 can be shielded, the electromagnetic wave radiated from the lead portion of the semiconductor laser 4 is shielded because the metal package 6 of the semiconductor laser 4 is not a shield case. I can't reliably shield.

(4) Since the high frequency superposition circuit 2 part and the semiconductor laser 4 part are arranged separately, the assembly workability and space efficiency are extremely poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a semiconductor laser device capable of reliably shielding electromagnetic waves radiated from an HFM with a simple and compact structure. And

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a collimator lens frame, a semiconductor laser attached to the center of the end face of the collimator lens frame, and a lead portion for inserting the semiconductor laser. A hole is formed, one surface of which has a heat-dissipating plate that is in surface contact with the end surface of the semiconductor laser, and a bottom surface that has a hole for inserting the lead portion of the semiconductor laser. Case-shaped case that is in surface contact with the surface,
A high frequency superposed substrate that is in surface contact with the bottom surface of the case and is soldered to the lead portion of the semiconductor laser, and is in surface contact with the other surface or side surface of the heat dissipation plate over the entire circumference of the edge, and is outside the case. A semiconductor laser device was constructed from a box-shaped electromagnetic shield cover covering the surface.

[Operation] According to the above configuration, electromagnetic waves radiated from the HFM and the semiconductor laser lead portion can be reliably shielded with a simple and compact configuration.

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

(First Embodiment) FIGS. 1 (a), (b) and (c) show a first embodiment of a semiconductor laser device 10 according to the present invention, and FIG. 1 (a) is an exploded view of the device. Perspective view, FIG. 1 (b) is a front sectional view,
FIG. 1 (c) is a sectional view of a main part.

In the figure, reference numeral 11 denotes a pickup body, and a collimator frame 12 is fixed to the pickup body 11 via a fixing screw. A cylindrical collimator adjustment frame 14 is screwed to the axial center of the collimator frame 12 so as to be adjustable in the axial direction. Denoted by 15 is a collimator lens.

An LD (laser diode) 16, which is a semiconductor laser light source, is fixed to the center of the upper surface of the collimator frame 12 via a fixing screw 17, and the heat radiation made by applying nickel plating to an iron material on the upper surface of this LD 16 The plate 18 'is mounted in direct contact. The HFM case 20 is directly placed and fixed on the upper surface of the heat sink 18 '.

A hole for inserting the lead portion of the LD 16 is formed in the heat sink 18 ′ and the HFM case 20, and the HFM board (module) 19 is disposed in a state of being in surface contact with the bottom of the HFM case 20. The lead portion of the LD 16 is tightly fitted and soldered to the HFM board 19.

The lead wires of the HFM board 19 are led out to the outside through a feedthrough capacitor (EMI) 20a as shown in FIG. 1 (c).

Reference numeral 21 denotes an HFM cover (electromagnetic shield cover), which has a box shape. The HFM cover 21 covers (covers) the outer surface of the HFM case 20, the lower surface of the flange 21b is brought into surface contact with the upper surface of the heat sink 18 ', and the four corners or the entire circumference of the flange 21b are soldered by the solder 50. To do. With this configuration, the electromagnetic waves emitted from the HFM substrate 19 and the LD lead portion 16a can be shielded.

According to the above configuration, since it is not necessary to surround the LD 16 with the heat dissipation plate 18 ', the heat dissipation plate can be downsized, so that the heat escape during the soldering work can be reduced and the efficiency of the soldering work can be improved. In addition to that, there is an advantage that the device can be downsized. Further, the electromagnetic wave radiated from the lead portion 16a of the LD 16 and the HFM substrate 19 can be shielded very effectively and surely by the peripheral surface cover portion 21a of the HFM cover 21 extending to the upper surface of the heat sink 18 '.

Further, the flange portion 21b of the HFM cover 21 comes into surface contact with the upper surface of the heat dissipation plate 18 ', and the edge portion of the flange portion 21b is soldered, so that the shield becomes more reliable.

Further, since the lead wire of the HFM board 19 is led to the outside through the EMI filter or the feedthrough capacitor, electromagnetic waves do not leak from the lead wire to the outside.

(Second Embodiment) FIGS. 2A and 2B show a second embodiment of the present invention. The feature of this embodiment is that the LD 16 is not directly contacted with the upper surface of the collimator frame 12 but is held by this LD support plate 25, and the LD 16 is directly contacted with the LD support plate 25 at the center of the upper surface of the collimator frame 12 and the LD 16 The LD 16 is fixed by directly mounting the heat radiating plate 18 'on the upper surface of the LD, and the heat radiating plate 18' and the LD supporting plate 25 are screwed to the collimator frame 12 by screws 26.

According to such a configuration, since the LD 16 is held by the LD support plate 25, the LD 16 does not have to be a rectangular shape advantageous for screwing, that is, a rectangular shape, and can be a round shape, and moreover, a device. It has the advantages of downsizing and improving the efficiency of soldering work for shielding. Other configurations, operations, and effects are the same as those in the first embodiment, and therefore their explanations are omitted.

According to the experiments of the applicant, the configuration of each of the above embodiments
Frequency emitted from HFM board (module) 19: 500 to 90
It has been confirmed that electromagnetic waves at 0 MHz can be reduced by about 20 dB.

[Advantages of the Invention] As described above, according to the semiconductor laser device of the present invention, the size can be reduced to an extremely simple and compact structure, and the electromagnetic shield cover can make surface contact over the entire periphery of the edge. It has the effect of reliably eliminating the gap and ensuring the electromagnetic shield.

[Brief description of drawings]

1 (a), (b) and (c) are an exploded perspective view, a sectional view and a sectional view of an essential part, respectively, showing a first embodiment of the present invention, and FIGS. 2 (a) and (b) are respectively the same. FIG. 3 is an exploded perspective view and a sectional view showing a second embodiment of the invention, and FIG. 12 …… Collimator frame 16 …… LD (semiconductor laser light source) 18 ′ …… Heat dissipation plate 19 …… HFM substrate 20 …… HFM case 21 …… HFM cover 21a …… Circumferential cover 25 …… LD support plate

Claims (1)

[Scope of utility model registration request] 1. A collimator lens frame, a semiconductor laser attached to a central portion of an end surface of the collimator lens frame, and a hole for inserting a lead portion of the semiconductor laser, one surface of which is a surface with respect to an end surface of the semiconductor laser. A heat dissipation plate in contact with the semiconductor laser; a box-shaped case having a bottom surface formed with a hole for inserting the lead portion of the semiconductor laser, the bottom surface being in surface contact with the other surface of the heat dissipation plate; Of the high frequency superposed substrate which is in surface contact with the bottom surface of the semiconductor laser and is soldered to the lead portion of the semiconductor laser, and the outer surface of the case which is in surface contact with the other surface or side surface of the heat dissipation plate over the entire circumference of the edge portion. And a box-shaped electrode shield cover.