WO2010047147A1

WO2010047147A1 - Semiconductor laser module and method for manufacturing the same

Info

Publication number: WO2010047147A1
Application number: PCT/JP2009/059977
Authority: WO
Inventors: 泰雄天野; 直樹松嶋; 達朗井手
Original assignee: 株式会社日立製作所
Priority date: 2008-10-24
Filing date: 2009-06-01
Publication date: 2010-04-29
Also published as: JP2010103323A

Abstract

It is necessary to determine, with extremely high precision, the distance between a laser light source and a collimating lens to obtain collimated light or a laser beam close to that in a semiconductor light emitting device. A collimating lens is fixed to a lens can case, and is bonded and fixed between a cylindrical surface of the lens can case and that of a cap of a semiconductor laser diode with an ultraviolet curable resin. At that time, a gap is arranged on the cylindrical section of the semiconductor laser diode and that of the lens can case, and the size of the gap is set such that the cylindrical sections are not in contact with each other when positional adjustment is made in a Z direction. The positional adjustment in the Z direction is made by moving the lens can case in the Z direction, while having the semiconductor laser diode emit light and measuring a spot diameter on a screen. On the side surface of a lens can case, slits are arranged at same intervals on the circumference. When the spot diameter on the screen is at a desired dimension, the ultraviolet curable resin is applied to the slit sections and is cured by ultraviolet.

Description

Semiconductor laser module and manufacturing method thereof

The present invention relates to a semiconductor laser module for obtaining collimated light or convergent light close to collimated light from a semiconductor laser diode.

In recent years, as represented by optical communication and DVD optical pickups, semiconductor lasers have been actively used for both industrial and consumer use. In recent years, with the development of green laser diodes in addition to visible red and blue light, devices that use the three light sources R, G, and B as an image have been developed. For example, a micro projector device is considered as one of the devices. A schematic diagram of the structure is shown in FIG. In the case 21, a green semiconductor laser module 22, a red semiconductor laser module 23, a blue semiconductor laser module 24, a prism 25, a drive mirror called a MEMS 26, and a screen 27 are arranged as shown in the figure. As will be described later, the laser beam collimated from each semiconductor laser module or adjusted so as to be focused on the screen passes through the prism 25 and the MEMS 26 and is focused on the screen 27 at one point. It has been adjusted. Various colors can be expressed by controlling the intensity of each of R, G, and B from the light collected at one point. A color moving image is expressed by reflecting the light collected at one point so that the MEMS 26 scans in the rotation direction and the tilt direction. In order to focus the laser beams of R, G, and B at one point when adjusting the optical axis in this configuration, each

semiconductor laser module

22, 23, 24 is adjusted with respect to the case 21, In order to adjust to collimated light emitted from each semiconductor laser module or light condensed on the screen 27, it is possible to adjust each semiconductor laser module alone. Next, adjustment of this collimation or convergent light will be described. FIG. 3 shows an example of a semiconductor laser module. The semiconductor laser module 20 includes a semiconductor laser diode 31, a collimating lens 32, and a lens can case 33 for holding the lens. The semiconductor laser element 34 in the semiconductor laser diode 31 is mounted on a heat sink 35 and sealed with a transparent glass 36 and a cylindrical cap 37 provided in the laser irradiation direction. The beam shape of the laser light 39 emitted in such a configuration is changed by the collimating lens 32. If the semiconductor laser diode 31 is moved in the XY direction 38a, the beam also moves in the XY direction, and if it is moved in the Z direction 38b, the beam divergence angle can be changed. Here, the specs differ from those in other fields, such as focusing the spot on a distant screen such as this micro projector and maintaining the smallest spot shape as much as possible even if the distance to the screen is changed to some extent. Is done. In other words, the laser beam can be adjusted to parallel light to make the same spot diameter at any distance, but in order to make the spot diameter as small as possible, it is necessary to shorten the distance between the semiconductor laser element as the light source and the collimating lens. There is. Conversely, if the distance between the semiconductor laser element and the collimating lens is shortened, it can be calculated that the adjustment sensitivity in the Z direction 38b for making parallel light becomes higher and the position adjustment becomes very difficult. An example of the calculation result is shown in FIG. FIG. 4 shows a result of calculating the moving distance of the collimator lens 32 for each spot diameter and for each of R, G, and B when the laser spot is applied to a screen 1 m ahead and the spot diameter changes from φ0.8 to φ1.0. is there. That is, for example, when the beam diameter is φ1.5, the blue laser diode needs to be 0.5 μm, that is, the adjustment of the collimator lens in the Z direction needs to be ± 0.5 μm or less.
Many proposals have been made on such a fine adjustment mechanism in the Z direction of the collimator lens (see, for example, Patent Document 1). In Patent Document 1, an adhesive is interposed as an elastic body between a substrate that holds a semiconductor laser that is an optical element and a substrate that holds a lens that is an optical component, and the distance between both substrates is compressed. Set with a screw. With this configuration, it is easy to finely adjust the variation in the distance between the two substrates due to the combination of the adhesive and the screw, and positioning can be performed with high accuracy and the yield is increased.

Japanese Patent Laid-Open No. 9-54233

As described above, it can be easily estimated that it is difficult to assemble the fixing member of the collimating lens with mechanical accuracy in order to position the gap between the semiconductor laser and the collimating lens at ± 0.5 μm. In addition, the stopping method applied with a force in the Z direction moves when the force is applied, and this is also difficult to assemble and adjust. Furthermore, adjusting the dimension in the Z direction with the screw mechanism is, for example, when using a screw with a pitch of 0.5 mm, screw control at 1/1000 rotation is required to adjust 0.5 μm. I have to say that it is difficult. Also, when fixing with adhesive, if the cure shrinkage rate of the adhesive is 2%, even if the adhesive is bonded with a thickness of 0.1 mm, it moves 2 μm, and the general fixing method satisfies the specifications. I can't.

An object of the present invention is to provide a method of positioning and fixing with high accuracy by adjusting the collimator of a semiconductor laser module in the Z direction.

In order to achieve the above object, according to the present invention, a collimating lens is fixed to a lens can case, and is bonded and fixed with an ultraviolet curable resin between a cylindrical surface of the semiconductor laser diode cap. At this time, a gap is provided between the cylindrical portion of the semiconductor laser diode and the cylindrical portion of the lens can case so that they do not contact each other when the position in the Z direction is adjusted. The position adjustment in the Z direction is performed by causing the semiconductor laser diode to emit light and moving the lens can case in the Z direction while measuring the spot diameter on the screen. In addition, slits are provided at equal intervals on the side of the lens can case. When the spot diameter on the screen reaches a desired dimension, an ultraviolet curable resin is applied to the slit portion and cured with ultraviolet rays.

According to the present invention, by fixing at the slit portion, the curing shrinkage force of the UV curable resin does not work in the Z direction, and no change in the Z direction occurs due to the curing shrinkage of the UV curable resin. As a result, adjustment and fixing can be performed with high accuracy.

It is a figure which shows the semiconductor laser module concerning the 1st Example of this invention. It is a schematic diagram of the structure of the micro projector concerning the Example of this invention. It is a figure which shows an example of the semiconductor laser module concerning one Example of this invention. It is a figure which shows the simulation result which shows the adjustment sensitivity concerning one Example of this invention. It is a figure which shows the whole collimating-lens assembly adjustment apparatus concerning one Example of this invention. It is a figure which shows the example concerning which it adhere | attached without providing a slit concerning a prior art. It is a figure which shows the application | coating method of the adhesive agent of this invention. It is a figure which shows the application | coating method of the adhesive agent of this invention. It is a figure which shows the semiconductor laser module concerning the 2nd Example of this invention. It is a figure which shows the semiconductor laser module concerning the 3rd Example of this invention.

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

FIG. 1 is an overall view showing a completed product of the semiconductor laser module 20 based on the first embodiment of the present invention. FIG. 5 is a diagram for explaining a method for adjusting and assembling the semiconductor laser module 20 of the present invention. In FIG. 1, the semiconductor laser module 20 includes a semiconductor laser diode 31 and a lens can case 33 to which a collimating lens 32 is bonded and fixed (in the present invention, this bonding and fixing method does not matter). A slit 14 is provided, and the slit 14 is bonded and fixed to the cap 37 portion of the semiconductor laser diode 31 with an ultraviolet curing adhesive 15. This assembly method will be described with reference to FIG. In FIG. 5, the semiconductor laser diode 31 is fixed to a laser diode fixing jig 51. On the other hand, the lens can case 33 to which the collimating lens 32 is fixed is fixed to a lens can case fixing jig 52, and the lens can case fixing jig 52 is fixed to a fine movement XYZ stage 53. Further, an optical axis evaluation device 55 is located at a distance (for example, 1 m) on the vibration isolator 54 same as the laser diode fixing jig 51 and the lens can case fixing jig 52. In such a series of collimating lens assembly adjusting devices 50, the semiconductor laser diode 31 emits light (the light emission control device is not shown), and the beam position and beam diameter of the laser light 39 are monitored through the optical axis evaluation device 55. Adjust while evaluating.

The adjustment method will be explained in detail. The lens can case 33 to which the collimating lens 32 is attached can be finely moved in the XY direction 38 a and the Z direction 38 b by the fine coarse movement XYZ stage 53. The XY direction 38a (radial direction) relates to the adjustment of the beam position, and the Z direction 38b (axial direction) relates to the adjustment of the beam size. In this state, the laser light 39 is evaluated while the lens can case 33 is finely moved by the fine coarse movement XYZ stage 53. In the present invention, a piezo element applied to a fine movement XYZ stage is used, and the resolution is 0.1 μm or less, which is sufficient for the position control of 0.5 μm targeted in the present invention. Furthermore, since there is a gap in the radial dimension between the cap 37 of the semiconductor laser diode 31 and the lens can case 33, they do not come into contact at this stage, and therefore, they are not stressed by the adjustment and are released from the jig. Even when the adjustment is performed, the position shift due to the stress release at the time of adjustment does not occur.

After the desired beam shape is obtained in this way, the UV curable adhesive 15 (not shown in FIG. 5 and will be described in detail later) is applied to the lens can case 33 from the slit 14 provided in the lens can case 33 in advance. It is applied between the semiconductor laser diode 31 and irradiated with ultraviolet rays (not shown) as it is to cure the ultraviolet curing adhesive 15. Since the ultraviolet curing adhesive 15 is cured in a short time, the work efficiency is high, the thermal distortion is small, and the precision adjustment jig is not heated, and is suitable for the bonding of the present invention.

) More detailed explanation about adhesion. FIG. 6 shows a case where the ultraviolet curing adhesive 15 is applied to the open end portion of the lens can case 33 and cured without the slit being provided in the lens can case 33. In this case, the adhesive 15 is applied to the end of the lens can case 33 in the Z direction. When the adhesive is cured, it shrinks not a little due to its nature. In the case of the ultraviolet curable adhesive 15, it is generally about 2%. When curing shrinkage occurs in the state shown in FIG. 6, shrinkage also occurs in the Z direction, causing a dimensional change in the Z direction of the width 61 of the adhesive in the Z direction, and the lens can case 33 is formed by the semiconductor laser diode 31. However, it will fluctuate from the adjusted position. For example, when an adhesive is applied with a width of 0.5 mm, a change of 10 μm occurs due to curing shrinkage, and the adjustment specification is not satisfied. Further, when an adhesive is applied to the radial gap 62 between the lens can case 33 and the cap portion 37 of the semiconductor laser diode, which has little relation to the dimensional change in the Z direction, ultraviolet rays are bonded in the case of an ultraviolet curable adhesive. If the adhesive does not reach the adhesive and the adhesive is not cured, or if a thermosetting adhesive is used instead of the ultraviolet curable adhesive, the above-described adverse effects due to thermal distortion occur, and it cannot be fixed with high accuracy.

Next, a method of applying the ultraviolet curable adhesive to the slit 14 according to the present embodiment will be described with reference to FIGS. 7A and 7B. The ultraviolet curable adhesive 15 is preferably applied only in the

circumferential directions

71a and 71b of the slit 14 as shown in FIG. 7A. The adhesive applied to the circumferential adhesive portion in this way hardly exerts a force in the Z direction on the lens can case 33 when the adhesive is cured. There is almost no movement. When the adhesive is applied to the entire slit 14 as shown in FIG. 7B, the resin located in the Z direction of the slit exerts a force in the direction of moving the lens can case with respect to the semiconductor laser diode during curing. By applying to both

ends

72a and 72b, the shrinking directions are opposite to each other and cancel each other, so that they can be bonded almost without moving as a whole.

FIG. 8 shows a second embodiment of the present invention. In this embodiment, one end of the slit shape 14a of the lens can case 33 is extended to the open end of the lens can case 33, and a portion between the slits 14a of the lens can case 33 is formed as a protruding connection portion 14b. It is. Others are the same as those in the second embodiment, and a description thereof will be omitted.

By making the slit into such a shape, the shrinkage described in the first embodiment reduces the rigidity in the radial direction of the connecting portion 14b and easily bends, so that the shrinkage of the ultraviolet curable adhesive 15 can be easily absorbed. . Moreover, the area of the part which does not have influence in the Z direction is larger than that in Example 1, and a better result than Example 1 was obtained in terms of ease of application of adhesive or strength.

FIG. 9 shows a third embodiment of the present invention. In this embodiment, the slit shape of the lens can case 33 is further widened and the size of the remaining portion of the lens can case 33 is narrowed, that is, the base side of the connecting portion is thick, and the ultraviolet curable adhesive 15 This is a thinned tip portion 14c to which is bonded. Others are the same as those in the second embodiment, and a description thereof will be omitted.

In the present embodiment, such a shape makes the connecting portion 14b more easily bent in the radial direction than in the second embodiment, and more easily absorbs the shrinkage of the ultraviolet curable adhesive 15. Further, the area of the portion having an influence on the Z direction is reduced due to the shrinkage described in the first embodiment, and even if the adhesive is applied to the end portion 91 of the slit, the influence on the Z direction is small, and the adhesive is applied. The ease of handling has been further improved.

Since the semiconductor laser modules shown in the first to third embodiments are adjusted to highly accurate collimated light or convergent light determined by design specifications by the module itself, for example, the light source of the micro projector shown in FIG. To adjust the optical axis, only the semiconductor laser modules are adjusted so that the remaining three light sources are adjusted to one point.
While the above description has been made with reference to exemplary embodiments, it will be apparent to those skilled in the art that the invention is not limited thereto and that various changes and modifications can be made within the spirit of the invention and the scope of the appended claims.

Since visible semiconductor lasers, particularly green semiconductor laser diodes, are being developed, it is expected that development of devices that display images using microprojectors and other visible light semiconductor laser diodes will become active in the future. It seems to be industrially advantageous to use a module obtained by an inexpensive method according to the present invention as a mechanism for focusing on a screen far from the light source or adjusting collimated light.

14 Slit 15 UV Effect Adhesive 20 Semiconductor Laser Module 21 Case 22 Green Semiconductor Laser Module 23 Red Semiconductor Laser Module 24 Semiconductor Laser Module 25 Prism 26 MEMS
27 Screen 31 Semiconductor Laser Diode 32 Collimating Lens 33 Lens Can Case 34 Semiconductor Laser Element 35 Heat Sink 36 Transparent Glass 37 Cap

38a XY Direction

38b Z Direction 39 Laser Light 50 Collimating Lens Assembly Adjusting Device 51 Laser Diode Fixing Tool 52 Lens Can Case Fixing Tool 53 Fine Coarse XYZ Stage 54 Vibration Isolation Table 55 Optical Axis Evaluation Device 56 Monitor 61 Adhesive Z Width 62 Gap 71 Slit Radial Portion 72 Slit Z Direction Portion 91 Slit Remaining End

Claims

A semiconductor laser diode for generating laser light;
A collimating lens for converting the laser light into collimated light;
A lens can case that holds the collimating lens and is arranged around the semiconductor laser diode;
In the semiconductor laser module comprising an adhesive for fixing the semiconductor laser module and the lens can case,
A semiconductor laser characterized in that an ultraviolet curable adhesive, which is the adhesive, fixes the semiconductor laser diode and the lens can case between the semiconductor laser diode and the lens can case in the radial direction. module.
In claim 1,
The lens can case has a plurality of slits arranged in the circumferential direction thereof,
The ultraviolet curable adhesive connects a portion between a plurality of slits of the lens can case and the semiconductor laser diode.
In claim 1,
The slit has a shape opened to an end surface of the lens can case opposite to the collimator lens, and the ultraviolet curable adhesive is connected using a portion between the slits of the lens can case as a connection portion. A semiconductor laser module.
In claim 3,
The semiconductor laser module according to claim 1, wherein a portion of the connection portion that connects the ultraviolet curable adhesive is thinner than the lens can case main body side of the connection portion.
A semiconductor laser module according to claim 1;
A microprojector comprising: a drive mirror that reflects the collimated light emitted from the semiconductor laser module so as to scan on a screen.
A step of holding a semiconductor laser diode for generating laser light with a first jig;
Holding the lens can case having a collimating lens with a second jig;
Moving and positioning the held collimating lens relative to the held semiconductor laser diode; and
Applying an ultraviolet curable adhesive between the semiconductor laser diode and the lens can case;
A step of irradiating ultraviolet rays through a slit provided in the lens can case in a state where the collimator lens is held at the positioned position, and curing the applied ultraviolet curable adhesive. Production method.
In claim 6,
The method of manufacturing a semiconductor laser module, wherein the ultraviolet curable adhesive is applied between the lens can case and the semiconductor laser diode in a radial direction.
In claim 7,
The slits are a plurality of slits arranged in the circumferential direction of the lens can case,
The method of manufacturing a semiconductor laser module, wherein the ultraviolet curable adhesive connects a portion between a plurality of slits of the lens can case and the semiconductor laser diode.
In claim 6,
The slit is a shape opened to the end surface of the lens can case opposite to the collimator lens,
A method of manufacturing a semiconductor laser module.
In claim 9,
The method of manufacturing a semiconductor laser module, wherein the slit has a shape in which an open portion of an end surface of the lens can case is wider than the opposite side.