WO2007142108A1

WO2007142108A1 - Method of manufacturing light-emitting device

Info

Publication number: WO2007142108A1
Application number: PCT/JP2007/061055
Authority: WO
Inventors: Naoyuki Tokuchi; Yoshihiro Someno; Yuji Taga; Akira Kanno
Original assignee: Alps Electric Co., Ltd.
Priority date: 2006-06-06
Filing date: 2007-05-31
Publication date: 2007-12-13
Also published as: JP2009200064A

Abstract

[PROBLEMS] To provide a method of manufacturing a light-emitting device capable of, particularly, properly and easily positioning the light-emitting surfaces of light-emitting elements at the same height. [MEANS FOR SOLVING THE PROBLEMS] Surface emitting lasers (12, 13) are so secured by means of a tool (30) that the light-emitting surfaces (12b, 13b) of the surface emitting lasers (12, 13) are in contact with the facing flat surface (30a) of the tool (30). With the light emitting surfaces (12b, 13b) positioned at the same height, the jig (30) is moved near a base (50), and the surface emitting lasers (12, 13) are joined to the base (50) with molten solder (53). The solder (53) is hardened to secure the surface emitting lasers (12, 13) onto the base (50).

Description

Method for manufacturing light emitting device

Technical field

TECHNICAL FIELD [0001] The present invention relates to a manufacturing method of a light emitting device used for a hologram reproducing device, for example.

[0002] As described in the following patent document, in reproduction of hologram data, when reproduction reference light is incident on a recording medium on which hologram data is recorded, the reproduction reference light is It is diffracted by the interference fringes of the data, and reproduced light is emitted. Then, the content of the hologram data contained in the reproduction light is read out by an imaging device such as a CCD or a CMOS sensor.

By the way, as described in the following patent document, the light emitting device that emits the reproduction reference light includes, for example, a surface on which a plurality of surface emitting lasers (VCSEL: Vertical Cavity Surface Emitting Laser) are arranged. A light emitting laser array is used.

[0004] The advantage of using a plurality of surface emitting lasers in this way is that the wavelength band of the reproduction reference light can be widened easily and inexpensively. In other words, a wide range of wavelength bands can be obtained by combining a plurality of surface emitting lasers having different wavelength bands of the reproduction reference light. In the case of a surface emitting laser array having such a wide wavelength band, when a plurality of holographic data is recorded in a wide wavelength band by wavelength multiplexing, the entire wavelength band should be covered. Is possible. Therefore, each hologram data can be reproduced appropriately.

[0005] In addition, when hologram data recorded with a wavelength band cannot be reproduced with a wavelength band due to, for example, anisotropic thermal expansion of a recording medium, the hologram data must be reproduced with a different wavelength β. In the case of a surface emitting laser, it is possible to appropriately reproduce the hologram data by switching to a surface emitting laser having the wavelength.

Patent Document 1: JP 2005-331864 A Patent Document 2: Japanese Unexamined Patent Publication No. 2006-58726

Patent Document 2: JP 2003-233293 A

Disclosure of the invention

Problems to be solved by the invention

[0006] However, in the process of manufacturing the surface emitting laser, the surface emitting laser has a thickness variation.

[0007] When the surface emitting laser has a variation in thickness, the following problems occur.

As shown in FIG. 15, two surface emitting lasers 2 and 3 are installed on a substrate 1 to form a surface emitting laser array 6.

A lens 4 is provided between the surface emitting laser array 6 and the recording medium 5. With this lens 4, the reproduction reference beams 2a and 3a emitted from the surface emitting lasers 2 and 3 are adjusted to parallel beams.

[0010] By the way, since the thicknesses of the surface emitting lasers 2 and 3 are not necessarily the same, the heights of the light emitting surfaces (surfaces of the light emitting portions) 2b and 3b of the surface emitting lasers 2 and 3 viewed from the substrate 1 are as follows. Is different. That is, the distance HI between the light emitting surface 2b of the surface emitting laser 2 and the principal point 4a of the lens 4 is different from the distance H2 between the light emitting surface 3b of the surface emitting laser 3 and the principal point 4a of the lens 4. It will be.

For this reason, as shown in FIG. 15, for example, the distance between the light emitting surface 3b and the principal point 4a of the lens 4 is H2 so that the reproduction irradiation light 3a of the surface emitting laser 3 becomes parallel light. In this case, since the distance HI between the light emitting surface 2b and the principal point 4a is shorter than the distance H2, the other reproduction reference light 2a is diffused light. On the contrary, when the distance HI is set so that the irradiation light 2a of the surface emitting laser 2 becomes parallel light, the reproduction irradiation light 2a of the surface emitting laser 2 becomes focused light. When the reproduction irradiation light is diffused light or focused light, the entire hologram data 7 is not irradiated with the reproduction irradiation light as parallel light. As a result, the incident angle of the reproduction irradiation light with respect to each interference fringe of the hologram is different, resulting in a problem that the hologram data 7 cannot be reproduced.

[0012] Even when the surface emitting lasers have the same thickness, the thickness of the adhesive layer interposed between the surface emitting laser and the substrate for fixing the surface emitting laser on the substrate varies. As a result, the height position of the light emitting surface of the surface emitting laser may vary.

Therefore, the present invention is for solving the above-described conventional problems, and in particular, it is possible to suppress variation in height of each light emitting surface of a plurality of light emitting elements more appropriately and easily than before. The purpose is to provide a method for manufacturing an efficient light emitting device.

Means for solving the problem

[0014] The present invention provides a method of manufacturing a light-emitting device in which a plurality of light-emitting elements are provided on a substrate, wherein the light-emitting surfaces of the plurality of light-emitting elements are aligned at the same height on the substrate. The element is adhered to the substrate via an adhesive,

Then, the adhesive is cured, and the light emitting element is fixed on the substrate.

[0015] Thereby, even if the thickness of the plurality of light emitting elements varies (at least one light emitting element is formed with a film thickness different from that of the other light emitting elements), the light emitting elements of the light emitting elements can be appropriately and easily formed. Each light emitting surface can be adjusted to the same height. In addition, since the bonding process and the fixing process are performed at a time with the light emitting surfaces of the respective light emitting elements being set to the same height, the manufacturing process can be simplified without individually bonding and fixing the light emitting elements. When the light emitting device manufactured by the manufacturing method of the present invention is used for a hologram reproducing device, a hologram reproducing device having a highly accurate reproducing function can be manufactured.

[0016] In the present invention, a plurality of the light emitting elements are attached to a jig, the light emitting surfaces are made to have the same height, and the light emitting elements are placed on a substrate via an adhesive while maintaining the same height. It is preferable that the jig is removed after the adhesive is cured and the adhesive is cured. In addition, since the height alignment of each light emitting surface and the subsequent adhesion process to the adhesive and the fixing process can be performed using the jig, the light emitting element can be positioned on the substrate with high accuracy. They can be fixed together and the manufacturing process can be simplified.

In the present invention, it is preferable to have the following steps.

(a) preparing the jig in which an opposing surface facing each light emitting surface is formed as the same plane, and bringing each light emitting surface of the plurality of light emitting elements into contact with the opposing surface; Holding the light emitting surface of the element on the same plane; (b) fixing the light emitting element to the jig while maintaining the state;

(c) The jig is opposed to the substrate, and the reference surface on the substrate and the opposed surface of the jig are maintained in a parallel state, while the substrate and the light emitting element are interposed via the adhesive. A process of adhering;

(d) curing the adhesive while maintaining the parallel state, and fixing the light emitting element on the substrate;

By using the jig described above, it is possible to manufacture a light emitting device in which the light emitting surfaces of the plurality of light emitting elements are adjusted to the same height more easily and with higher accuracy.

[0018] Further, the present invention provides a method for manufacturing a light emitting device in which a plurality of light emitting elements are provided on a substrate.

Prepare a jig in which the opposed surfaces facing the respective light emitting surfaces of the plurality of light emitting elements are formed in the same plane, and bring each light emitting element into contact with the opposed surface of the jig from the light emitting surface side before In a state where the light-emitting element is fixed to the jig, the light-emitting element is brought into close contact with the substrate through an adhesive, and then the adhesive is cured to fix the light-emitting element onto the substrate. The fixed state between the element and the jig is released, and the jig is removed.

[0019] Thereby, the variation in height of the light emitting surfaces of the plurality of light emitting elements can be more easily and appropriately suppressed than in the past.

In the present invention, electrodes are provided on the surface opposite to the light emitting surface of the light emitting element and the surface of the substrate, respectively, and the electrode on the opposite surface of the light emitting element and the substrate surface are provided. It is preferable that a groove is formed in at least one of the electrodes on the surface, and the adhesive is provided on the electrode excluding the groove. Further, the electrodes may be divided into small electrodes by the grooves, or the grooves may be formed in a lattice shape. This groove can function as an escape groove for releasing, for example, excess adhesive and air when the light emitting element is adhered onto the substrate.

In the present invention, electrodes are provided on the surface opposite to the light emitting surface of the light emitting element and the surface of the substrate, respectively, and a conductive adhesive is used as the adhesive. Light emission It is preferable that the element side electrode and the substrate side electrode are electrically connected via the conductive adhesive.

At this time, it is preferable to use solder for the conductive adhesive. Thereby, the substrate side electrode and the light emitting element side electrode can be easily connected to each other. In addition, when using a solder, the substrate side electrode and the light emitting element side electrode can be firmly bonded by metal bonding, for example, when the jig is removed, the film thickness of the adhesive layer varies, Thermal contraction and thermal expansion due to environmental temperature changes and the like can be suppressed as much as possible, and fluctuations in the height of each light emitting surface of the light emitting element can be appropriately suppressed after manufacturing.

In the present invention, it is preferable that a conductive paste containing an organic component is used for the conductive adhesive, and the organic component is removed by heat treatment when the conductive adhesive is cured. If organic components are contained even after curing, for example, when the jig is removed, the thickness of the adhesive layer may fluctuate, and thermal shrinkage and thermal expansion may easily occur due to environmental temperature changes after manufacturing. By removing the organic component, it is possible to appropriately suppress the fluctuation of the height of each light emitting surface of the light emitting element after manufacturing.

In the present invention, it is preferable that the adhesive is interspersed between each light emitting element and the substrate. When the entire surface between the substrate and the light emitting element is closely attached with the adhesive, air holes that are sealed at the interface between the substrate and the adhesive, the interface between the light emitting element and the adhesive, or the like are likely to be generated. . In such a case, the adhesion between the substrate and the light emitting element is likely to be lowered due to the thermal contraction or thermal expansion of the air present in the pores due to environmental temperature change or the like. In addition, when the light emitting element and the substrate are brought into close contact with each other, excess adhesive may spread around the light emitting element. Therefore, the above problem can be solved by interspersing the adhesive.

[0025] In addition, the jig is provided with a suction hole, and the light emitting surface of the light emitting element is brought into contact with the opposing surface of the jig and then sucked to bring the light emitting element into the jig. It is fixed. Thereby, each light emitting element can be easily fixed to and detached from the jig.

The invention's effect

[0026] According to the present invention, even if the thickness of the plurality of light emitting elements varies, it is possible to appropriately and easily match the light emitting surfaces of the light emitting elements to the same height. Therefore, the present invention When the light emitting device manufactured by this manufacturing method is used for a hologram reproducing device, a hologram reproducing device having a highly accurate reproducing function can be manufactured.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a conceptual diagram in which hologram data is reproduced from a recording medium by a hologram reproducing device.

2 to 5 are process diagrams (all partial sectional views cut from the thickness direction) showing the first embodiment of the present invention.

FIG. 6 is a partial plan view of the surface emitting laser and jig shown in FIG. 2 as viewed from directly above. 7 and 8 are process drawings showing a second embodiment of the method for manufacturing a light emitting device according to the present invention.

9 to 11 are views showing a substrate electrode structure suitable for the second embodiment and a manufacturing method thereof. Further, FIG. 9 is a partially enlarged cross-sectional view taken along the line AA shown in FIG. 11 and viewed from the direction of the arrow, and FIG. 10 shows the surface emitting laser, the substrate, and the substrate after the process of FIG. FIG. 11 is a partially enlarged plan view of the substrate and the adhesive shown in FIG. 9 as viewed from directly above.

FIG. 12 and FIG. 13 are diagrams showing electrode structures of other substrates suitable for the second embodiment. In other words, Fig. 12 is a partially enlarged plan view of the electrodes and adhesive (solder) of another substrate viewed from directly above, and Fig. 13 is a surface emitting laser bonded on the substrate shown in Fig. 12. It is the fragmentary sectional view which cut | disconnected in the thickness direction along the B_B line | wire and was seen from the arrow direction in the state.

FIG. 14 is a conceptual diagram for explaining the irradiation state of reproduction reference light when the surface emitting laser array manufactured according to the first or second embodiment is incorporated in a hologram reproduction apparatus.

A hologram reproducing apparatus 10 shown in FIG. 1 includes a surface emitting laser array 14 in which a plurality of surface emitting lasers (light emitting elements) 12 and 13 are formed on a substrate 50, a lens array 17, a CCD, a CMOS sensor, and the like. The image pickup device 18, the pinhole filter 19, and an installation unit (not shown) for installing the recording medium 20 are configured.

[0029] Hologram data 21 is recorded on the recording medium 20 by a hologram recording device (not shown). The hologram data 21 appears as interference fringes. Figure 1 shows the horodala. Only one hologram data 21 is shown. Actually, a large number of hologram data 21 are recorded on the recording medium 20 by wavelength multiplexing or angle multiplexing.

Now, the reproduction reference beam 22 is irradiated toward the recording medium 20 from the surface emitting laser 12 of the hologram reproducing apparatus shown in FIG. The diameter of the reproduction reference beam 22 is expanded by the microlens 15 and further collimated by the collimator lens 16.

[0031] The reproduction reference beam 22 is applied to the recording medium 20 at an irradiation angle θ1. When the reproduction reference light 22 is irradiated onto the hologram data 21, the light is diffracted by the interference fringes satisfying the Bragg conditional expression, and the reproduction light (diffracted light) 23 is directed from the recording medium 20 toward the image sensor 18. Released. At this time, the reproduction light 23 reaches the image sensor 18 through a pinhole 19a provided in the pinhole filter 19. In the image sensor 18, the contents of the hologram data 21 are reproduced. The reason why the pinhole filter 19 is provided is that, when the reproduction reference light 22 is irradiated onto the recording medium 20, when the reproduction light of a plurality of hologram data is emitted from the recording medium 20, one of the reproduction lights 23 is provided in order for the image sensor 18 to receive light appropriately. By providing the pinhole filter 19, a plurality of the hologram data 21 can be appropriately reproduced.

In the embodiment of the present invention, the light emitting surfaces of the plurality of surface emitting lasers 12 and 13 installed on the substrate 50 are formed at the same height as viewed from the reference plane in the optical design of the light emitting device. Has been. Hereinafter, a method for manufacturing the surface emitting laser array 14 in the embodiment of the present invention will be described.

In the first embodiment of the present invention, as shown in FIG. 2, the light emitting portions 12a and 13a are formed on the surface sides of the surface emitting lasers 12 and 13, and the light emitting portions are exposed. The surfaces become the light emitting surfaces 12b and 13b of the surface emitting lasers 12 and 13, respectively. Further, surface electrodes 31 and 32 are formed on the light emitting surfaces 12b and 13b. Further, back surface electrodes (light emitting element side electrodes) 33 and 34 are formed on the surfaces of the surface emitting lasers 12 and 13 opposite to the light emitting surfaces 12b and 13b, that is, on the back surfaces 12c and 13c.

In the case of a general surface emitting laser, strictly speaking, the light emitting portions 12a and 13a are exposed and the surface opposite to the surface (the light emitting surfaces 12b and 13b in FIG. 2) is “light emitting”. Sometimes referred to as “face”. However In the present embodiment, the surface on which the light emitting portions 12a and 13a of the surface emitting lasers 12 and 13 are exposed will be described as the “light emitting surface” of each surface emitting laser 12 and 13.

In the present embodiment, it is preferable that the surface of the light emitting units 12 and 13 (light emitting surface) is processed to be a flat surface. In addition, it is more preferable that the surface of the light emitting units 12 and 13 and at least a part of the surface around the surface are processed into a flat surface. Further, as shown in FIG. It is most preferable that the surface is processed. In FIG. 2, the surfaces of the surface electrodes 31 and 32 are formed in the same plane as the light emitting surfaces 12b and 13b. For example, the surface electrodes 31 and 32 protrude on the surfaces (light emitting surfaces) of the light emitting portions 12 and 13. It may be provided.

In the following description, unless otherwise specified, as shown in FIG. 2, the surface of the surface electrodes 31 and 32 is planarized so as to be flush with the light emitting surfaces 12b and 13b, ie, The entire surface of the surface emitting lasers 12 and 13 will be described as “light emitting surfaces 12b and 13b”.

[0037] The thickness of the surface emitting laser 12 is H3, and the thickness of the surface emitting laser 13 is H4, and the thicknesses are H3 and H4. Here, the thickness dimension refers to the thickness dimension from the light emitting surfaces 12b and 13b to the back electrodes 33 and 34 (in this case, the thickness of the back electrodes 33 and 34 may be excluded). In the present embodiment, when the thickness dimensions H3 and H4 are different, the effects of the present invention are appropriately exhibited. However, it goes without saying that there is no problem in using the manufacturing method of the present embodiment even if the thickness dimensions H3 and H4 of the surface emitting lasers 12 and 13 are the same.

In the first embodiment, first, a jig 30 is prepared in which a surface 30 a facing the light emitting surfaces 12 b and 13 b of the surface emitting lasers 12 and 13 is formed. In this specification, the “jig” refers to a tool for carrying the surface emitting lasers 12 and 13 to a predetermined position on the substrate 50 while being attracted by a suction force. The facing surface 30a of the jig 30 is formed in a flat shape so that the light emitting surfaces 12b and 13b are aligned on the same plane C when the surface emitting lasers 12 and 13 are attracted to the jig 30. The material of the jig 30 is not particularly limited, but is transparent or transparent so that the light emitting surfaces 12b and 13b of the surface emitting lasers 12 and 13 can be seen from the surface 30c side of the jig 30. It is preferable that it is translucent. Further, in the present embodiment, as shown in FIG. 6, the planar shape of the jig 30 is a rectangular shape, and the planar area of each surface emitting laser 12, 13 is It is larger than the total area of plane areas. The planar shape of the jig 30 is not particularly limited.

[0039] In the jig 30, suction holes 30b, 30b are formed at positions facing a part of the light emitting surfaces 12b, 13b of the surface emitting lasers 12, 13, and a suction mechanism (not shown) It is provided as a body or separate body. Then, by sucking air from the suction holes 30b and 30b in a state where the light emitting surfaces 12b and 13b are in contact with the facing surface 30a of the jig 30, the surface emitting lasers 12 and 13 are controlled by the treatment. It is fixed to the opposing surface 30a of the tool 30 by suction. However, another fixing method may be used.

Here, the “contact” includes not only the case where the entire light emitting surfaces 12b and 13b are completely in contact with the facing surface 30a, but also the case where there is a slight gap. That is, it is sufficient that at least a part of the light emitting surfaces 12b and 13b and the facing surface 30a are in contact with each other and the surface emitting lasers 12 and 13 are fixed by the jig 30. For example, as described above, when the surface electrodes 31 and 32 are formed to protrude on the light emitting surfaces 12b and 13b, there is a step between the light emitting surfaces 12b and 13b and the surfaces of the surface electrodes 31 and 32. Arise. In this case, strictly speaking, in the present embodiment, the light emitting surfaces 12b, 13 and the opposing surface 30a are not completely in contact with each other and a gap is generated.

[0041] The surface emitting lasers 12 and 13 are fixed to the jig 30 in a state where the light emitting surfaces 12b and 13b of the surface emitting lasers 12 and 13 are in contact with the facing surface 30a.

[0042] When the jig 30 is made of a transparent or translucent member, the surface emitting lasers 12 and 13 can be easily positioned on the jig 30. For example, when the jig 30 is transparent or translucent, a positioning mark portion 40 is provided on the surface 30c or the opposed surface 30a of the jig 30 as shown in FIG. Positioning mark portions 41 are provided on the light emitting surfaces 12b and 13b, respectively. Here, the mark portions 40, 41 are on the imaginary line D parallel to the Y direction (length direction) shown in the figure and on the imaginary line E parallel to the X direction (direction perpendicular to the Y direction shown in the figure, width direction). The surface emitting lasers 12 and 13 are positioned with respect to the jig 30 so that they are aligned in a straight line. Thereby, the surface emitting lasers 12 and 13 can be accurately positioned in the X direction and the Y direction shown in the drawing.

Next, in the step shown in FIG. 3, the substrate 50 is placed on the base 54. Surface of the substrate 50 Substrate-side electrodes 51 and 52 are formed at positions facing the surface-emitting lasers 12 and 13, and solder 53 is applied as a conductive adhesive on the substrate-side electrodes 51 and 52.

[0044] For the solder 53, an alloy mainly containing tin (Sn) is particularly preferably used. In this case, Sn accounts for 50% by mass or more, more preferably 90% by mass or more of the total solder particles. The metal that forms an alloy with Sn includes gold (Au), silver (Ag), copper (Cu), nickel (Ni), bismuth, depending on the purpose of the melting point of the solder or the electrical conductivity. One or more of (Bi), antimony (Sb), zinc (Zn), indium (In) force can be selected. For example, gold, silver, and copper have high electrical conductivity, so Sn—Au, Sn—Ag, Sn—Cu, Sn—Ag—Cu alloys, etc., form solder with high electrical conductivity, but have a melting point. It is as high as 200 to 300 ° C. In addition, the solder made of Sn_Bi alloy has excellent workability with a low melting point of 60-200 ° C, and hardly damages the substrate and the surface emitting laser. In particular, Sn_Bi has a melting point of about 140 ° C and is optimal as a low melting point solder.

In the present embodiment, Sn—Au solder is preferably used for the solder 53.

As shown in the process of FIG. 3, if the thickness of the surface emitting lasers 12 and 13 varies, a difference occurs in the distance between the surface emitting lasers 12 and 13 and the substrate 50 through the solder 53. For this reason, in order to properly fix the surface emitting lasers 12 and 13 and the substrate 50 with the solder 53, the coating amount (film thickness) of the solder 53 is set to the film thickness required for the conventional solder connection and the interval. Set the thickness to take into account the difference (approximately 10 to 30 / im).

Then, the surface emitting lasers 12 and 13 fixed to the jig 30 are opposed to the substrate 50.

Next, the solder 53 is heated and melted by laser irradiation or the like. The light emitting surfaces 12b and 13b described above are in the same height state, that is, while the surface 54a of the base 54, which is a reference surface for the height, and the opposing surface 30a of the jig 30 are kept in a parallel state, the treatment is performed. The tool 30 is gradually brought closer to the substrate 50.

Then, as shown in FIG. 4, the surface emitting lasers 12 and 13 are pressed against the solder 53 simultaneously, and the space between the surface emitting lasers 12 and 13 and the substrate 50 is passed through the solder 53 in a molten state. And adhere. In the present embodiment, the surface emitting laser 12 is thinner than the surface emitting laser 13. Therefore, as shown in FIG. 4, in the state where the surface emitting lasers 12 and 13 and the substrate 50 are in close contact with each other through the solder 53, the distance H6 between the surface emitting laser 12 and the substrate 50 is as follows. The distance H5 between the substrates 50 is larger. However, in this embodiment, since the thickness of the solder 53 is made thicker than before, the solder 53 can be appropriately interposed not only in the narrow interval H5 but also in the wide interval H6.

Then, the solder 53 is cured while maintaining the above state. The hardening of the solder 53 is gradually promoted as the temperature decreases. If it is desired to accelerate the hardening of the solder 53, the solder 53 may be forcibly cooled by a cooling mechanism (not shown).

Thus, the surface emitting lasers 12 and 13 can be fixed on the substrate 50 via the solder 53. Then, suction from the suction holes 30b and 30b of the jig 30 is stopped, the fixed state between the jig 30 and the surface emitting lasers 12 and 13 is released, and the jig 30 is removed.

Then, as shown in FIG. 5, the surface electrodes 31 and 32 of the surface emitting lasers 12 and 13 and the substrate side electrodes 55 and 56 formed on the surface of the substrate 50 are electrically connected by, for example, a wire 57 Connect (wire bonding).

Further, the back electrodes 33 and 34 of the surface emitting lasers 12 and 13 and the substrate-side electrodes 51 and 52 of the substrate 50 are also electrically connected by solder 53.

According to the manufacturing method of the present embodiment described above, the light emitting surfaces 12b and 13b of the surface emitting lasers 12 and 13 can be formed at the same height when viewed from the reference surface. Here, the “same height” includes an error of about ± 2 / im.

In the present embodiment, by using the jig 30 having the opposing surface 30a formed on the same plane C, it is possible to easily and appropriately attach the surface emitting lasers 12 and 13 onto the substrate 50. Noh. That is, the same plane C that does not need to be adjusted individually for the height positions of the light emitting surfaces 12b and 13b of the surface emitting lasers 12 and 13 is maintained parallel to the reference surface (for example, the surface 54a shown in FIG. 3). However, the surface emitting lasers 12 and 13 need only be brought into close contact with the substrate 50 via the solder 53. Further, the height alignment of each light emitting surface 12b, 13b and the adhesion process of each surface emitting laser 12, 13 to the substrate 50 can be performed at the same time. Surface emitting lasers 12 and 13 are simultaneously placed on the substrate 50 Since it can be fixed, the manufacturing process can be simplified.

It should be noted that the reference planes at the height positions of the light emitting surfaces 12b and 13b of the surface emitting lasers 12 and 13 can be arbitrarily set depending on the optical design of the light emitting device. For example, in the case of the present embodiment, the reference surface is the front surface 54a (the back surface of the substrate 50) 54a of the base 54 shown in FIG. In this case, the surface emitting lasers 12 and 13 are fixed to the substrate 50 after adjusting the jig 30 so that the opposing surface 30a (same plane C) of the jig 30 and the surface 54a are parallel to each other. Is done. As a result, the height from the surface 54a (reference surface) to each light emitting surface 12b, 13b becomes the same height, so that the optical design using the surface 54a reference surface (for example, surface emission with the surface 54a as a reference). It is possible to calculate the optimum distance from the light emitting surfaces 12b and 13b of the lasers 12 and 13 to the lens 16. The optical design may be performed using the surface of the substrate 50 as a reference plane.

[0057] Since the solder 53, which is a metal material, is used as the conductive adhesive in the steps of FIGS. 2 to 5, the surface emitting lasers 12, 13 and the substrate 50 (to be precise, the solder 53 and the The back surface electrodes 33 and 34 of the surface emitting lasers 12 and 13, the solder 53 and the substrate side electrodes 51 and 52 of the substrate 50, and the inside of the solder 53) are firmly bonded by metal bonding.

[0058] As the conductive adhesive, a conductive adhesive containing an organic component may be used. However, in that case, when the jig 30 is removed and the pressing state in the direction of the substrate 50 by the jig 30 is released, or the height of the adhesive layer varies slightly due to environmental temperature changes, the light emission The height of the surfaces 12b and 13b from the reference surface may vary. For this reason, when using a conductive adhesive containing organic components, the above factors need to be considered.

[0059] For example, when a conductive paste containing an organic component is used for the conductive adhesive, the organic component can be removed by heat treatment when the conductive adhesive is cured. Examples of the conductive paste include metal resinates and those having metal particles and an organic vehicle (an organic solvent and a resin binder). In this case, the organic component contained in the conductive paste is thermally decomposed and evaporated during the heat treatment. As a result, the adhesive layer is finally formed of only metal, and a strong metal bond is formed between the surface emitting lasers 12 and 13 and the substrate 50. When using a metal resinate or the like, the organic component is removed during the heat treatment, so the film thickness when the conductive adhesive is applied onto the substrate 50 and the heat treatment are used. The film thickness of the subsequent adhesive layer varies greatly. Therefore, it is necessary to adjust the coating amount (film thickness) of the conductive adhesive in consideration of the film thickness reduction amount and the intervals H5 and H6 shown in FIG.

[0060] Further, when the conductive paste as described above is used, even if several mass% of the organic component remains in the adhesive layer, as the conductive adhesive, for example, an anisotropic conductive paste ( Compared to the case of using ACP) or anisotropic conductive film (ACF), the film thickness variation of the adhesive layer when the jig 30 is removed can be reduced.

[0061] In the steps of FIGS. 2 to 5, the method is for manufacturing one surface emitting laser array 14. However, a large number of surface emitting lasers are fixed on a large substrate, and then the substrate is attached to each substrate. Cutting may be performed for each surface emitting laser array 14.

In the process of FIG. 2, solder 53 is applied to the entire surface of the substrate-side electrodes 51 and 52 on the substrate 50. However, when solder 53 is applied to the entire surface of the substrate-side electrodes 51 and 52, as shown in FIG. 4, the solder 53 interposed between the surface emitting laser 13 having a large thickness and the substrate 50 has a thickness of The pressure is applied more than the solder 53 interposed between the thin surface emitting laser 12 and the substrate 50, and there is a possibility that excess solder 53 flows out from the periphery of the surface emitting laser 13 and adheres to an unexpected location. Further, when the substrate 50 and the surface emitting lasers 12 and 13 are brought into close contact with each other via the solder 53, the solder 53 and the surface emitting lasers 12, 13 are disposed between the solder 53 and the substrate 50. A closed hole is easily formed between the two. When the holes are formed, the air existing in the holes is thermally expanded or compressed due to a change in environmental temperature or the like, so that the space between the solder 53 and the surface emitting lasers 12 and 13 and the solder 53 and the substrate 50 are increased. There is a risk of reducing the adhesion between the two.

As means for solving these problems, a second embodiment as shown in FIGS. 7 and 8 can be considered. In the present embodiment, a plurality of spherical solders 60 are scattered on the substrate-side electrodes 51 and 52 on the substrate 50. The shape of the solder 60 is not limited to a spherical shape.

As shown in FIG. 7, after the solder 60 is scattered on the substrate side electrodes 51, 52, the solder 60 is melted.

Then, as shown in FIG. 8, the surface emitting lasers 12 and 13 and the substrate 50 are interposed via the solder 60. Adhere closely. At this time, the solder 60 interposed between the thick surface emitting laser 13 and the substrate 50 is more crushed than the solder 60 interposed between the thin surface emitting laser 12 and the substrate 50.

Then, the solder 60 is cured in the state of FIG. 8, and the jig 30 is removed.

[0066] In the above electrode structure, the solder 60 is scattered between the surface-emitting laser 13 and the substrate 50 even when the solder 60 is crushed by interspersing the solder 60. 0 can be avoided. Further, it is difficult to form a sealed hole between the surface emitting lasers 12 and 13 and the solder 60, or between the substrate 50 and the solder 60, and the adhesion between the surface emitting lasers 12 and 13 and the substrate 50 is strengthened. I can do it.

[0067] Further, in the step of FIG. 7, the size of the solder 60 may be different. Further, if at least one solder 60 is in close contact between the surface emitting laser 12 and the substrate 50 and between the surface emitting laser 13 and the substrate 50, conductivity can be ensured.

In addition, FIGS. 9 to 11 show a structure of a substrate side electrode suitable for the second embodiment. In this structure, the substrate-side electrode 51 is provided with a lattice-like groove 51a. The groove 51a does not divide the electrode 51, and a part of the layer of the electrode 51 is left on the bottom surface of the groove 51a. The substrate side electrode 52 is similarly provided with a groove, but only the substrate side electrode 51 will be described here.

[0069] A plurality of grooves 51a are provided in a straight line in the width direction (X direction in the drawing) and in the length direction (Y direction in the drawing) orthogonal to the width direction. The shape of the groove 51a is not limited to the shape shown in FIGS. 9 and 11, but it is formed in a shape that can be removed from at least one side surface 5 lb of the electrode 51 (a shape that leads to the side surface 51b). Is preferred.

Then, spherical solder 61 is scattered on the surface 51c (convex surface) of the electrode 51 excluding the groove 51a.

Thereafter, the solder 61 is melted, and the surface emitting laser 12 and the substrate 50 are brought into close contact with each other through the solder 61. At this time, the solder 61 is crushed as shown in FIG. In the embodiment with this electrode structure, since the electrode 51 remains on the bottom surface of the groove 51a, the groove 51a is also excellent in solder wettability. Therefore, a part of the crushed solder 61 overflows from the surface 51c and escapes into the groove 51a. In this way, the groove 51a overflows It can function as an escape groove for the solder 61. The groove 5 la also functions as an air escape groove when the solder 61 is crushed, so that a hole in which air is sealed is created between the solder 61 and the electrode 51.

Then, the solder 61 is cured, and the surface emitting laser 12 is fixed on the substrate 50.

Further, another structure of the substrate side electrode suitable for the second embodiment will be described with reference to FIGS.

In this structure, the electrode 51 is divided into a plurality of small electrodes 51d by forming the groove 51e.

[0074] Then, solder 62 is scattered on the surface of each small electrode 51d. Next, the solder 62 is melted and the surface emitting laser 12 and the substrate 50 are brought into close contact with each other through the solder 62, and then the solder 62 is cured to fix the surface emitting laser 12 on the substrate 50. To do.

By the way, in this substrate side electrode structure, the surface of the substrate 50 is exposed in the groove 51e between the small electrodes 51d. Since the surface of the substrate 50 has poor solder wettability, the solder 62 hardly flows onto the substrate 50 when the solder 62 is crushed. (However, as in the case of the groove 51a, the groove 51e has a sufficient function as an air escape groove.)

Therefore, in the structure of the present electrode, it is effective to use, for example, a solder adhesive containing solder and an organic component (resin) as the conductive adhesive. As the organic component, for example, a thermosetting resin is used, which is separated from the solder by heating to cause thermosetting. At this time, as shown in FIG. 13, the resin 65 mainly escapes into the groove 51e. The solder 66 stays between the small electrode 51d and the back electrode 33 of the surface emitting laser 12, and the small electrode 51d and the back electrode. Adhere 33. In this way, the force S can be used to cause the groove 51e to function as a relief groove for the resin 65.

As described above, according to each of the above embodiments, the light emitting surfaces 121) and 13b of the plurality of surface emitting lasers 12 and 13 attached to the surface emitting laser array 14 are formed at the same height when viewed from the reference surface. I can do it.

In each of the above embodiments, the same effect can be obtained even if grooves are formed in the back surface electrodes 33 and 34 of the force-emitting lasers 12 and 13 in which the grooves 51a and 51e are formed in the substrate 50. it can.

Therefore, as shown in FIG. 14, the light emitting surfaces 12b, 13 of the plurality of surface emitting lasers 12, 13 are provided. The distances H7 and H8 between b and the principal point 16a of the lens 16 can be made equal. Accordingly, both the reproduction reference light 22 emitted from the surface emitting laser 12 and the reproduction reference light 71 emitted from the surface emitting laser 13 can be adjusted to parallel light by the lens 16. Therefore, even if the surface emitting lasers 12 and 13 for obtaining a wavelength capable of reproducing the hologram data 21 are switched, it is possible to obtain the reproduction reference beams 22 and 71 having a certain light intensity or more with parallel light. Program data 21 can be reproduced properly. As described above, if the hologram reproducing device 10 is manufactured using the surface emitting laser array 14 manufactured according to the present embodiment, the reproduction reference light can be obtained as parallel light having a certain light intensity or more in a wide wavelength band. Therefore, it is possible to manufacture a hologram reproducing apparatus having an excellent hologram reproducing function.

By the way, there are cases where the surface of the element of the surface emitting lasers 12 and 13 is clearly formed as an uneven surface and the surface of the element is not formed as a flat surface. In this case, if the light emitting surfaces 12b and 13b are positioned on the convex surface (outermost surface), the light emitting surfaces 12b and 13b may be brought into contact with the facing surface 30a of the jig 30.

However, when the light emitting surfaces 12b and 13b are located on the concave surface, the concave surface cannot be brought into contact with the facing surface 30a. Therefore, the convex surface which is the outermost surface of the surface emitting laser ( The light emitting surface is not positioned) and the opposed surface 30a of the jig 30 is brought into contact with the opposing surface 30a. In such a case, even if the manufacturing method of the present embodiment is used, the variation in the height dimension between the convex surface of each of the surface emitting lasers 12 and 13 and the surface of the concave portion is caused by the light emitting surface 12b of the surface emitting lasers 12 and 13. , 13b remains as a variation in height. However, the heights of the light emitting surfaces 12b and 13b from the reference surface due to the accumulation of variations in the height dimensions H3 and H4 of the surface emitting lasers 12 and 13 and the variation in the thickness of each adhesive layer compared to the conventional ones. There is no error.

Therefore, as described above, even when the surface of the surface emitting lasers 12 and 13 is clearly formed as an uneven surface, the variation in the height of the light emitting surfaces 12b and 13b is significantly reduced as compared with the conventional case. It is possible. The variation of the height dimension at this time is about ± 2 zm.

[0083] When the variation is wider than the above, when the surface emitting lasers 12 and 13 are attracted and fixed to the jig 30, the surface emitting lasers 12b and 13b of the surface emitting lasers 12 and 13 are set to the same height. It is necessary to fix the surface emitting lasers 12 and 13 to the jig 30 in a suitable state. [0084] In each of the above embodiments, there are two surface emitting lasers 12 and 13 provided on the substrate 50. However, more surface emitting lasers may be mounted. In such a case, when the film thickness of at least one surface emitting laser is different from the film thickness of other surface emitting lasers, it is effective to apply the manufacturing method according to this embodiment.

In FIG. 7 and subsequent figures, the conductive adhesive may be solder or a conductive paste containing an organic component. In a strong conductive paste, the organic component is preferably removed by heat treatment during curing.

In the present embodiment, the hologram reproducing device 10 has been described as an example of use of the surface emitting laser array 14, but is not limited to the hologram reproducing device. This is applicable to applications where a plurality of surface emitting lasers are used and the surface of each surface emitting laser is required to have the same height.

Further, although the surface emitting laser is used as the “light emitting element”, it is not limited to the surface emitting laser.

[0088] Further, in the process of applying a conductive adhesive such as the solder 53 of Fig. 3, it is easy to apply the conductive adhesive on the substrate side electrodes 51 and 52. Although it is preferable, it may be applied to the back electrodes 33 and 34 of the surface emitting lasers 12 and 13, or may be applied to both the substrate side electrodes 51 and 52 and the back electrodes 33 and 34. Also good.

[0089] The form of the conductive adhesive is not particularly limited, such as a paste, a film, or a powder.

[0090] The method for forming the conductive adhesive on the substrate-side electrodes 51, 52 is not particularly limited, such as screen printing, an ink jet method, a sputtering method, or the like.

Further, in the present embodiment, the force with which the surface electrodes 31 and 32 are provided on the light emitting surfaces 12b and 13b of the surface emitting lasers 12 and 13, respectively, on the back surfaces 12c and 13c of the surface emitting lasers 12 and 3, respectively. Two electrodes may be provided. In such a case, the surface emitting lasers 12 and 13 are fixed on the substrate 50 by forming small electrodes corresponding to the respective electrodes on the substrate 50 and bringing the electrodes' small electrodes into close contact with each other with a conductive adhesive. .

[0092] Further, the force by which the surface-emitting lasers 12 and 13 and the substrate 50 are fixed with a conductive adhesive such as solder. This is because the electrodes are electrically connected. Therefore, the surface emitting laser If it is not necessary to connect the boards 12 and 13 to the board 50, it is possible to use an adhesive other than the conductive adhesive.

Brief Description of Drawings

FIG. 1 is a conceptual diagram for reproducing hologram data from a recording medium by a hologram reproducing device. FIG. 2 is a process diagram showing a method for manufacturing a light emitting device (surface emitting laser array) according to a first embodiment of the present invention. (Partial sectional view cut from the thickness direction),

[FIG. 3] The next process diagram of FIG. 2 (partial sectional view cut from the thickness direction),

[FIG. 4] The next process diagram of FIG. 3 (partial sectional view cut from the thickness direction),

[FIG. 5] Next process diagram of FIG. 4 (partial sectional view cut from the thickness direction),

FIG. 6 is a partial plan view of the surface emitting laser and jig shown in FIG.

FIG. 7 is a process chart showing a second embodiment of the present invention,

[FIG. 8] Process diagram following FIG.

FIG. 9 is a process diagram showing a manufacturing method using a substrate-side electrode suitable for the second embodiment (the substrate and the adhesion as seen from the direction of the arrow cut in the thickness direction along the line AA shown in FIG. 11) (Partial enlarged sectional view of the agent (solder)),

FIG. 10 is a process diagram subsequent to FIG. 9 (partially enlarged sectional view of the substrate, the surface emitting laser and the adhesive (solder) showing a state where the surface emitting laser and the substrate are joined after the process of FIG. 9);

[FIG. 11] Partial enlarged plan view of the substrate and adhesive (solder) shown in FIG.

FIG. 12 is an enlarged plan view of a part of another electrode substrate and an adhesive (solder) suitable for the second embodiment as seen from directly above.

FIG. 13 is a partial sectional view of the substrate in which a surface emitting laser is bonded to the substrate shown in FIG. 12, the adhesive (solder), and the surface emitting laser cut in a thickness direction force;

FIG. 14 is a conceptual diagram for explaining the irradiation state of reproduction reference light when the surface-emitting laser array produced by the production method according to the present embodiment is incorporated in a hologram reproduction apparatus. FIG. Conceptual diagram showing the irradiation state of the reproduction reference beam emitted from the light emitting laser.

[0094] 10 Hologram reproduction device , 13 surface emitting laser

b, 13b Light emitting surface

Surface emitting laser array

Lens array

Image sensor

Pinhole filter

recoding media

Hologram data

, 71 Playback reference light

Reproduction light

jig

a Opposing surface

Back electrode (light emitting element side electrode), 41 Mark

Substrate

Substrate side electrode

a, e groove

, 60, 61, 62, 66 Solder (conductive adhesive) base

Wire

Resin

Coplanar

Claims

The scope of the claims

[1] A method for manufacturing a light emitting device in which a plurality of light emitting elements are provided on a substrate,

With the light emitting surfaces of the plurality of light emitting elements aligned at the same height on the substrate, the light emitting elements are adhered to the substrate via an adhesive,

Thereafter, the adhesive is cured, and the light emitting element is fixed on the substrate.

[2] A plurality of the light emitting elements are attached to a jig, the light emitting surfaces are set to the same height, and the light emitting elements are adhered to the substrate with an adhesive while maintaining the same height. 2. The method for manufacturing a light emitting device according to claim 1, wherein the jig is removed after the adhesive is cured.

[3] The method for manufacturing a light-emitting device according to claim 2, comprising the following steps.

(a) preparing the jig in which an opposing surface facing each light emitting surface is formed as the same plane, and bringing each light emitting surface of the plurality of light emitting elements into contact with the opposing surface; Holding the light emitting surface of the element on the same plane;

(b) fixing the light emitting element to the jig while maintaining the state;

(e) releasing the fixed state between the light emitting element and the jig and removing the jig

[4] The jig is provided with a suction hole, and the light emitting surface of the light emitting element is brought into contact with the opposing surface of the jig, and then the light emitting element is fixed to the jig by suction. The manufacturing method according to claim 3, characterized by the above.

[5] A method for manufacturing a light-emitting device in which a plurality of light-emitting elements are provided on a substrate,

Prepare a jig in which the opposed surfaces facing the respective light emitting surfaces of the plurality of light emitting elements are formed in the same plane, and bring each light emitting element into contact with the opposed surface of the jig from the light emitting surface side. The light emitting device is fixed on the jig, and the light emitting element is adhered to the substrate with an adhesive. Thereafter, the adhesive is cured, the light emitting element is fixed on the substrate, the fixing state between the light emitting element and the jig is released, and the jig is removed. Manufacturing method of light emitting device.

[6] Electrodes are respectively provided on a surface opposite to the light emitting surface of the light emitting element and a surface of the substrate, and a groove is provided on at least one of the electrode on the opposite surface and the electrode on the substrate surface. 7. The method for manufacturing a light emitting device according to claim 1, wherein the adhesive is provided on the electrode excluding the groove.

[7] At least one of the electrode on the opposite surface of the light emitting element and the electrode on the substrate surface is divided into a plurality of small electrodes by the groove, and the contact is formed on the plurality of small electrodes excluding the groove. 7. The method for manufacturing a light emitting device according to claim 6, wherein an adhesive is provided.

8. The method for manufacturing a light emitting device according to claim 6 or 7, wherein the grooves are formed in a lattice shape.

[9] The conductive adhesive is used for the adhesive, 1, 2, 3, 5, 6,

A method for manufacturing a light emitting device according to 7 or 8 above.

10. The method for manufacturing a light emitting device according to claim 9, wherein solder is used for the conductive adhesive.

[11] The method for manufacturing a light-emitting device according to claim 9, wherein a conductive paste containing an organic component is used as the conductive adhesive, and the organic component is removed by a heat treatment when the conductive adhesive is cured. .

12. The method for manufacturing a light emitting device according to claim 1, wherein the adhesive is scattered between each light emitting element and the substrate.

[13] The jig is provided with a suction hole, the exposed surface of the light emitting element b is brought into contact with the opposing surface of the jig, and then sucked to attach the light emitting element to the jig. The manufacturing method according to claim 5, wherein the method is fixed to.