Laser assembly and manufacturing method thereof, laser module, optical engine and augmented reality glasses

Abstract

The invention relates to a laser assembly, a method for manufacturing the same, a laser module, an optical engine, and augmented reality glasses, and provides a laser assembly configured so that a predetermined interval is maintained between a base for a laser element and a substrate for an optical waveguide. This laser module is provided with: a plurality of laser element bases on which laser elements are provided on the main surfaces; an optical waveguide substrate provided with an optical waveguide layer on a main surface; a plurality of spacing films disposed at positions corresponding to the laser element susceptor on the bonding surface of the optical waveguide substrate so as to be separated from each other; and a plurality of metal laminated films that bond the bonding surfaces of the plurality of laser element bases and the bonding surface of the optical waveguide substrate, the plurality of metal laminated films having a plurality of first metal films and a plurality of second metal films, the plurality of first metal films being disposed on the plurality of spacer films, respectively, and the plurality of second metal films being disposed on the plurality of spacer films. The second metal film is disposed on the bonding surface of the plurality of laser element susceptors and is composed of a metal that can be eutectic with the metal constituting the first metal film.

Description

Technical Field

[0001] The invention relates to a laser component and a manufacturing method thereof, a laser module, an optical engine and extended reality glasses. Background Art

[0002] XR (extended reality) glasses such as AR (Augmented Reality) glasses and VR (Virtual Reality) glasses are expected to be small wearable devices. In wearable devices such as AR glasses and VR glasses, miniaturization is the key to popularization in order to equip various functions within the size of ordinary glasses.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2021 / 149450 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] Patent Document 1 discloses an integrated optical device that achieves miniaturization by joining a base that holds a laser element and a substrate having an optical waveguide on its surface so that the light emission position of the laser element and the position of the optical waveguide are aligned with high precision via a metal layer.

[0008] In the structure in which the base and the substrate are bonded via the metal layer, the bonding strength is improved compared to the structure in which the base and the substrate are bonded using an adhesive, and the temperature dependency of the bonding strength is also suppressed.

[0009] Fig.15 This is a schematic plan view for explaining the integrated optical device disclosed in Patent Document 1. Fig.16A and Fig. 16B The following is a schematic perspective view of a base for holding a laser element (laser element base) and a substrate having an optical waveguide on its surface (optical waveguide substrate) before being joined, as disclosed in Patent Document 1. Fig.16A This is a three-dimensional schematic diagram of the base that holds the laser element. Fig. 16B It is a schematic perspective view of a substrate having an optical waveguide on its surface.

[0010] Regarding the reference numerals in the drawings, the same reference numerals are used for the same components as those of the laser unit according to the present embodiment described later, and the description thereof will be appropriately omitted below.

[0011] The integrated optical device shown in the figure includes: three laser elements 30-1, 30-2, and 30-3; three separate bases 20 (20-1, 20-2, and 20-3) that are arranged separately from each other, and the laser elements 30 are respectively placed on the main surfaces 21-1, 21-2, and 21-3 of the bases 20; an optical waveguide layer 50 that has an optical waveguide path 51 that conducts laser light emitted from the laser elements 30-1, 30-2, and 30-3; a substrate 40, and the optical waveguide layer 50 is provided on the surface of the substrate 40; and a metal film that joins the bases 20 (20-1, 20-2, and 20-3) and the substrate 40.

[0012] In the integrated optical device shown in the figure, the metal film has a three-layer structure, which is composed of a metal layer 74 (74-1, 74-2, 74-3) arranged on the respective bonding surfaces 22 (22-1, 22-2, 22-3) of a plurality of separate bases 20, a metal layer 172 formed continuously in a strip shape on the bonding surface 42 of the substrate 40, and a metal layer 173 formed continuously in a strip shape in an overlapping manner on the metal layer 172.

[0013] By joining the base holding the laser element and the substrate provided with the optical waveguide via metal bonding in this way, the light emission position of the laser element and the incident port position of the optical waveguide can be precisely positioned.

[0014] During the bonding, the metal film formed on the base and the substrate is melted at a high temperature, and a predetermined pressure is applied to make the base and the substrate contact, so as to form a metal bond and complete the bonding. Here, when the metal film is melted at a high temperature to form a metal bond, there is a concern that the molten metal will leak out from the gap between the base and the substrate because it is pressed in with a predetermined pressure. Since the bonding surface is a flat surface, the molten metal flows easily. In the case where the molten metal leaks out from the gap, it is possible to form a metal ball, or contact with other metal components to form a current bypass, in which case it will cause equipment failure and performance degradation.

[0015] The present invention is completed in view of the above situation, and its purpose is to provide a laser component and a manufacturing method thereof, a laser module, an optical engine and augmented reality glasses that are configured to maintain a predetermined interval between a base for a laser element and a substrate for an optical waveguide.

[0016] Solutions for solving problems

[0017] The present invention provides the following solutions in order to solve the above-mentioned problems.

[0018] A first aspect of the present invention is a laser module, comprising: a plurality of laser elements; a plurality of laser element bases having a main surface and a bonding surface, the plurality of laser elements being respectively arranged on the main surface; an optical waveguide substrate having a main surface and a bonding surface, an optical waveguide layer having an optical waveguide path being provided on the main surface of the optical waveguide substrate, the optical waveguide path transmitting laser light emitted from the plurality of laser elements; a plurality of spacer films being arranged at positions on the bonding surface of the optical waveguide substrate that are spaced apart from each other and correspond to the plurality of laser element bases one by one; and a plurality of metal laminated films that bond the bonding surfaces of the plurality of laser element bases and the bonding surface of the optical waveguide substrate, the plurality of metal laminated films having a plurality of first metal films and a second metal film, the plurality of first metal films being respectively arranged on the plurality of spacer films, and the second metal film being arranged on the bonding surface of the plurality of laser element bases and being composed of a metal that can form a eutectic with the metal constituting the first metal film.

[0019] Based on the laser component of Scheme 1, in Scheme 2 of the present invention, the first metal film is composed of Sn or an alloy containing Sn, and the second metal film is composed of a metal selected from the group consisting of Au, Si, Al, Ni, Zn, Pt and their alloys.

[0020] In the laser component of aspect 1 or 2, in aspect 3 of the present invention, the spacer film has a thickness of 0.1 μm or more.

[0021] In the laser component according to any one of the first to third aspects, in the fourth aspect of the present invention, the spacer film is made of a metal selected from the group consisting of Ta, Ti, Ni, Ta / Pt, Ti / Pt, and Ni / Pt.

[0022] In the laser component according to any one of the first to third aspects, in aspect 5 of the present invention, the spacer film is made of an oxide.

[0023] In a sixth aspect of the present invention, in any one of the laser modules of aspects 1 to 5, the second metal film is formed to have a larger area than the first metal film.

[0024] In any one of the laser modules of the first to sixth aspects, in a seventh aspect of the present invention, an antireflection film is provided on the bonding surface of the optical waveguide substrate, and the spacer film is formed on the antireflection film.

[0025] In the laser module according to any one of the first to seventh aspects, in the eighth aspect of the present invention, the optical waveguide layer is a planar lightwave circuit made of a glass material.

[0026] In the laser module of any one of the first to seventh aspects, in aspect 9 of the present invention, the optical waveguide layer is a planar lightwave circuit composed of a lithium niobate film.

[0027] A tenth aspect of the present invention is a laser module, wherein the laser component according to any one of the eighth and ninth aspects is housed in a package.

[0028] Aspect 11 of the present invention is an optical engine comprising the laser module of aspect 10 and a light scanning mirror for scanning light emitted from the laser module.

[0029] Solution 12 of the present invention is an extended reality glasses, which includes the optical engine of Solution 11.

[0030] Scheme 13 of the present invention is a method for manufacturing a laser component, which comprises the following steps: a step of manufacturing a substrate for an optical waveguide, in which a plurality of spacer films and a first metal film are sequentially formed on a bonding surface of the substrate for an optical waveguide; a step of manufacturing a base for a laser element, in which a second metal film is formed on a bonding surface of the base for a laser element; and a bonding step, which is performed after the step of manufacturing the substrate for an optical waveguide and the step of manufacturing the base for a laser element, in which the base for a laser element and the substrate for an optical waveguide are eutectically bonded.

[0031] Based on the manufacturing method of the laser component of Scheme 13, in Scheme 14 of the present invention, in the process of manufacturing the optical waveguide substrate, the spacer film and the first metal film are formed using a photoresist mask having a plurality of holes, the plurality of holes corresponding to patterns of a plurality of the spacer films separately arranged on the bonding surface of the optical waveguide substrate, and in the bonding process, active alignment bonding is used to eutectically bond the first metal film of the optical waveguide substrate and the second metal film of the laser element base.

[0032] Effects of the Invention

[0033] According to the laser module of the present invention, it is possible to provide a laser module configured to maintain a predetermined distance between the laser element base and the optical waveguide substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic plan view of a portion of the laser module according to the present embodiment.

[0035] Figure 2 yes Figure 1 The laser assembly shown is a schematic cross-sectional view taken along line AA′.

[0036] Figure 3AThis is a schematic perspective view of the laser element base before the laser element base and the optical waveguide substrate are bonded together.

[0037] Figure 3B This is a schematic perspective view of the optical waveguide substrate before the laser element base and the optical waveguide substrate are bonded together.

[0038] Figure 4 yes Figure 1 The laser assembly shown is a schematic cross-sectional view taken along line BB'.

[0039] Figure 5A 1 is a schematic diagram showing a step of bonding a laser element base and an optical waveguide substrate, and is a diagram showing the state before bonding.

[0040] Figure 5B 1 is a schematic diagram showing a step of bonding a laser element base and an optical waveguide substrate, and is a diagram showing the state after bonding.

[0041] Figure 6 It means Figure 5B The features shown are schematic diagrams of the junction of different features.

[0042] Fig. 7A This is a schematic cross-sectional view showing an example of a laser module in which an antireflection film is provided on the bonding surface of the optical waveguide substrate.

[0043] Figure 7B This is a schematic cross-sectional view showing an example of a laser module in which an antireflection film is provided on the bonding surface of the optical waveguide substrate.

[0044] Figure 8 1 is a schematic plan view of the laser module according to the present embodiment.

[0045] Fig. 9 Use XZ plane to Figure 8 The laser module shown is partially broken away to show a cross section of a laser unit disposed inside.

[0046] Fig.10 The laser module is a schematic plan view showing a state where a cover is removed from a laser module housing a laser unit. The laser unit has an optical waveguide substrate including an optical waveguide layer composed of a lithium niobate film.

[0047] Fig.11 It is observed from the emission surface of visible laser and near-infrared laser Fig.10 A schematic top view of the laser assembly is shown.

[0048] Fig.12 This is a conceptual diagram for explaining the XR glasses of this embodiment.

[0049] Fig.13This is a conceptual diagram showing a situation in which an image is directly projected onto the retina using laser light emitted from a laser module according to an embodiment.

[0050] Fig.14A This is a flow chart of the process of manufacturing an optical waveguide substrate.

[0051] Fig. 14B This is a flow chart of the process of manufacturing a laser element base.

[0052] Fig. 14C It is a flow chart of the joining process.

[0053] Fig.15 It is a schematic top view of a part of the integrated optical device.

[0054] Fig.16A It is loaded with Fig.15 The integrated optical device shown is a schematic three-dimensional view of a laser element base for three laser elements included in the laser element base.

[0055] Fig. 16B yes Fig.15 A schematic perspective view of a substrate for an optical waveguide included in the integrated optical device shown.

[0056] Description of Reference Numerals

[0057] 20. Base for laser element; 30. Laser element; 40, 140. Optical waveguide substrate; 50, 150. Optical waveguide layer; 100, 100B. Laser component; 110. Package; 1000, 1001, 2000. Laser module; 5001. Optical engine; 10000. XR glasses. DETAILED DESCRIPTION

[0058] The following description will describe the embodiments in detail with reference to the accompanying drawings as appropriate. The drawings used in the following description sometimes enlarge the characteristic parts for convenience so that the characteristics are easy to understand, and the size ratios of the components are sometimes different from the actual ones. The materials, dimensions, etc. illustrated in the following description are examples, and the present invention is not limited thereto, and can be implemented by appropriately changing within the scope of achieving the effects of the present invention.

[0059] 〔Laser components〕

[0060] Figure 1 It is a schematic plan view of a portion of the laser module according to the present embodiment. Figure 2 yes Figure 1 The laser assembly shown is a schematic cross-sectional view taken along line AA′. Figure 3A and Figure 3B This is a schematic three-dimensional diagram of each before the laser element base and the optical waveguide substrate are bonded together. Figure 3A This is a three-dimensional schematic diagram of a base for a laser element. Figure 3B This is a schematic perspective view of a substrate for an optical waveguide. Figure 4 yes Figure 1 The laser assembly shown is a schematic cross-sectional view taken along line BB'.

[0061] Figure 1 The laser assembly 100 shown includes: a plurality of laser elements 30 (30-1, 30-2, 30-3); a plurality of laser element bases 20 (20-1, 20-2, 20-3) having a main surface 21 (21-1, 21-2, 21-3) and a bonding surface 22 (22-1, 22-2, 22-3), and the plurality of laser elements 30 (30-1, 30-2, 30-3) are respectively arranged on the main surface 21 (21-1, 21-2, 21-3); an optical waveguide substrate 40 , which has a main surface 41 and a bonding surface 42, and an optical waveguide layer 50 is provided on the main surface 41, and the optical waveguide layer 50 has an optical waveguide path 51 that conducts lasers emitted from a plurality of laser elements 30 (30-1, 30-2, 30-3); a plurality of spacing films 72 (72-1, 72-2, 72-3) that are separately arranged at positions corresponding to a plurality of laser element bases 20 (20-1, 20-2, 20-3) on the bonding surface 42 of the optical waveguide substrate 40; and a plurality of metal stacks The plurality of metal laminated films 70 (70-1, 70-2, 70-3) are connected to the bonding surfaces 22 (22-1, 22-2, 22-3) of the plurality of laser element bases 20 (20-1, 20-2, 20-3) and the bonding surface 42 of the optical waveguide substrate 40. The plurality of metal laminated films 70 (70-1, 70-2, 70-3) include a plurality of first metal films 73 (73-1, 73-2, 73-3) and a second metal film 74 (74-1, 74-2, 74-3). The metal films 73 (73-1, 73-2, 73-3) are respectively arranged on multiple spacer films 72 (72-1, 72-2, 72-3), and the second metal film 74 (74-1, 74-2, 74-3) is arranged on the bonding surfaces 22 (22-1, 22-2, 22-3) of multiple laser element bases 20 (20-1, 20-2, 20-3), and is composed of a metal that can form a eutectic with the metal constituting the first metal film 73 (73-1, 73-2, 73-3).

[0062] <Laser element and laser element base>

[0063] As the laser element 30, various laser elements can be used. For example, commercially available laser diodes (hereinafter sometimes referred to as LD) such as red light, green light, blue light, near infrared light, and ultraviolet light can be used. Red light (R) can use light with a peak wavelength of more than 630nm and less than 830nm, green light (G) can use light with a peak wavelength of more than 500nm and less than 550nm, and blue light (B) can use light with a peak wavelength of more than 380nm and less than 500nm. In addition, near infrared light can use light with a peak wavelength of more than 830nm and less than 2000nm.

[0064] exist Figure 1 In the laser assembly 100 shown, for convenience, the laser elements 30-1, 30-2, and 30-3 are respectively set as LDs emitting red light, LDs emitting green light, and LDs emitting blue light for explanation. The laser elements 30-1, 30-2, and 30-3 can be mounted on separate laser element bases 20-1, 20-2, and 20-3 in the form of bare chips (chips not packaged), for example. Figure 1 Although the number of laser elements shown is three, this is just an example, and any number of laser elements may be used.

[0065] The laser element bases 20 - 1 , 20 - 2 , and 20 - 3 are made of, for example, aluminum nitride (AlN), aluminum oxide (Al 2 O 3 ), silicon (Si), or the like.

[0066] Metal films 75 and 76 are provided between the laser element base 20 and the laser element 30 (see Figure 2 ). The laser element base 20 and the laser element 30 are connected by means of metal films 75 and 76. As a method for forming the metal films 75 and 76, there is no limitation as long as a known method can be used, and known methods such as sputtering, evaporation, and coating of a paste-formed metal can be used. The metal films 75 and 76 may, for example, contain one or more metals selected from the group consisting of gold (Au), platinum (Pt), silver (Ag), lead (Pb), indium (In), nickel (Ni), titanium (Ti) and tantalum (Ta), tungsten (W), an alloy of gold (Au) and tin (Sn), a tin (Sn)-silver (Ag)-copper (Cu) solder alloy (SAC), SnCu, InBi, SnPdAg, SnBiIn, and PbBiIn, and may be composed of one or more metals selected from the group.

[0067] <Optical waveguide layer and optical waveguide substrate>

[0068] The optical waveguide layer 50 has at least an optical waveguide path that guides the laser light emitted from the laser element. The optical waveguide layer is not particularly limited, and for example, a known structure can be adopted. Examples of the optical waveguide layer are shown below.

[0069] The optical waveguide layer 50 is a layer that performs the function of a planar lightwave circuit (PLC). The optical waveguides 51-1, 51-2, and 51-3 correspond to the core of an optical fiber.

[0070] The optical waveguide layer 50 is formed on the optical waveguide substrate 40 , and as described above, the laser element 30 is mounted on the laser element base 20 .

[0071] The optical waveguide substrate 40 and the laser element base 20 are eutectic bonded and integrated. This eutectic bonding enables accurate optical axis arrangement and also enables miniaturization.

[0072] The optical waveguide substrate 40 is made of, for example, silicon (Si). The optical waveguide layer 50 is formed on the main surface 41 in a manner integral with the optical waveguide substrate 40 by using a well-known semiconductor process including photolithography and dry etching used in forming a fine structure such as an integrated circuit. Figure 1 As shown, the optical waveguide layer 50 is provided with the same number of optical waveguides (cores) 51-1, 51-2, 51-3 as the number of laser elements 30-1, 30-2, 30-3 and a cladding 52 surrounding the optical waveguides 51-1, 51-2, 51-3. The thickness of the cladding 52 and the width direction dimensions of the optical waveguides 51-1, 51-2, 51-3 are not particularly limited. For example, the optical waveguides 51-1, 51-2, 51-3 having a width direction dimension of about several microns are arranged in the cladding 52 having a thickness of about 50 μm.

[0073] The optical waveguides 51-1, 51-2, 51-3 and the cladding 52 are made of, for example, a glass material (e.g., quartz glass). In this case, the optical waveguide layer 50 is sometimes referred to as a quartz-based PLC. The refractive index of the optical waveguides 51-1, 51-2, 51-3 is higher than the refractive index of the cladding 52 by a predetermined value. Thus, light incident on the optical waveguides 51-1, 51-2, 51-3 is totally reflected at the interface between each optical waveguide and the cladding 52 and propagates in each optical waveguide. Inclusions such as germanium (Ge) are doped in the optical waveguides 51-1, 51-2, 51-3 in an amount corresponding to the predetermined value described above.

[0074] like Figure 1 As shown, the optical waveguides 51-1, 51-2, and 51-3 are mutually combined into one optical waveguide on the front side of the emission surface 64 reaching the optical waveguide layer 50. That is, the optical waveguides 51-1, 51-2, and 51-3 are successively combined as they go forward in the x direction, and are combined into one optical waveguide 51-4. In order to prevent light leakage from the optical waveguides 51-1, 51-2, and 51-3, the optical waveguides 51-1, 51-2, and 51-3 are preferably connected to the optical waveguide 51-4 at a curvature radius greater than a predetermined curvature radius.

[0075] By eutectic bonding of the optical waveguide substrate 40 and the laser element base 20, each optical waveguide and each corresponding laser element are relatively arranged in the following state: the optical axis is accurately aligned in such a way that the center of the incident port of each optical waveguide 51-1, 51-2, 51-3 of the optical waveguide layer 50 is roughly consistent with the optical axis of the output light emitted from the corresponding laser element 30-1, 30-2, 30-3.

[0076] like Figure 2 As shown, the incident surface 50A of the optical waveguide layer 50 is arranged to be opposite to the emission surface 30A (30-1A) of the laser element 30. In detail, the emission port 31-1 of the laser element 30-1 is opposite to the incident port 51-1A of the waveguide 51-1. In the x-direction and the z-direction, the optical axis of the red light emitted from the laser element 30-1 substantially overlaps with the center of the incident port 51-1A. Similarly, the emission port of the laser element 30-2 is opposite to the incident port of the waveguide 51-2. In the x-direction and the z-direction, the optical axis of the green light emitted from the laser element 30-2 substantially overlaps with the center of the incident port. The emission port of the laser element 30-3 is opposite to the incident port of the waveguide 51-3. In the x-direction and the z-direction, the optical axis of the blue light emitted from the laser element 30-3 substantially overlaps with the center of the incident port.

[0077] like Figure 1 As shown, the red light, green light, and blue light emitted from the laser elements 30-1, 30-2, and 30-3 are respectively incident on the optical waveguides 51-1, 51-2, and 51-3 and then propagate in each optical waveguide. The red light and green light propagating in the optical waveguides 51-1 and 51-2 are combined at the confluence position 57-1. The combined red light and green light are combined with the blue light propagating in the optical waveguide 51-3 at the confluence position 57-2. The RGB light combined at the confluence position 57-2 propagates in the optical waveguide 51-4, reaches the emission surface 64, and is emitted from the emission surface 64.

[0078] <Joint portion between laser element base and optical waveguide substrate>

[0079] The plurality of individual laser element bases 20 - 1 , 20 - 2 , and 20 - 3 and the optical waveguide substrate 40 are bonded to each other via a plurality of metal laminate films 70 ( 70 - 1 , 70 - 2 , and 70 - 3 ).

[0080] The plurality of metal stacked films 70 (70-1, 70-2, 70-3) includes a plurality of first metal films 73 (73-1, 73-2, 73-3) and a plurality of second metal films 74 (74-1, 74-2, 74-3). The metal stacked films 70 are electrically and spatially separated from adjacent laser element bases.

[0081] Before joining, Figure 3B As shown, a plurality of first metal films 73 (73-1, 73-2, 73-3) are disposed on a plurality of spacer films 72 (72-1, 72-2, 72-3), and a plurality of spacer films 72 (72-1, 72-2, 72-3) are disposed on the bonding surface 42 of the optical waveguide substrate 40 in a manner separated from each other. Figure 3A As shown, the plurality of second metal films 74 (74-1, 74-2, 74-3) are disposed on the respective bonding surfaces 22-1, 22-2, 22-3 of the plurality of laser element bases 20 (20-1, 20-2, 20-3).

[0082] When the portion where the laser element base and the optical waveguide substrate are bonded is referred to as a bonding portion, the bonding portion is composed of the metal laminate film 70 and the spacer film 72 , and the bonding is achieved by eutectic bonding of the first metal film 73 and the second metal film 74 .

[0083] As a preferred eutectic bonding, Au—Sn bonding can be cited. As the materials of the first metal film 73 and the second metal film 74, a combination that forms an Au—Sn bonding when bonded is preferred.

[0084] In the eutectic bond formed between the first metal film 73 and the second metal film 74, the degree of eutecticization (alloying) varies depending on the conditions, and sometimes a structure is formed in which a relatively large amount of non-eutecticized portions of one or both of the first metal film 73 and the second metal film 74 remain, or a structure in which the first metal film 73 and the second metal film 74 are alloyed as a whole to form a eutectic layer.

[0085] The metal stacked film 70 is not a film formed continuously but a separate film arranged separately. Since it is a separate film, the occurrence of capacitive coupling is suppressed, and crosstalk is suppressed.

[0086] Figure 5A and Figure 5B is a schematic diagram showing the bonding process of the laser element base and the optical waveguide substrate. Figure 5A Before joining, Figure 5B Indicates after joining.

[0087] In the bonding of the laser element base 20 and the optical waveguide substrate 40, as shown in FIG. Figure 5AAs shown, the metal film M1, the spacer film Sp, and the metal film M2 constituting the joint portion are formed in advance. That is, the spacer film Sp is formed on the joint surface 42 of the optical waveguide substrate 40, and then the metal film M1 is formed on the spacer film Sp. On the other hand, the metal film M2 is formed in advance on the joint surfaces 22 (22-1, 22-2, 22-3) of the laser element bases 20-1, 20-2, and 20-3. In addition, the metal film M1, the spacer film Sp, and the metal film M2 become the first metal film 73, the spacer film 72, and the second metal film 74 after joining, but since the morphology changes before and after joining through melting and joining (although the spacer film is generally almost unchanged), different reference numerals are marked.

[0088] Next, the joint is heated by a known method such as laser irradiation to melt the metal film M1, and the laser element base and the optical waveguide substrate are pressed in or one of them to be joined by eutectic bonding. The metal film M1 and the metal film M2 are a combination of metals that can be eutectic bonded. The joint after bonding is composed of the spacer film 72, the first metal film 73, and the second metal film 74. Since the joint is formed by temporarily melting the metal film and then forming a bond and solidifying, although it is difficult to accurately illustrate its shape, a diagram that can capture its characteristics as much as possible is used for explanation.

[0089] Figure 5B 1 is a diagram showing an example of a characteristic bonding portion. After the metal film M1 disposed on the spacer film Sp is melted, the laser element is pressed into the base 20, so that a part of the metal film M1 is diffused onto the bonding surface 42 around the spacer film Sp to form the first metal film 73. Figure 5B In the example shown, the second metal film 74 is formed to have an area larger than the area of ​​the first metal film 73 formed by diffusion. That is, when viewed from the direction connecting the bonding surface 42 and the bonding surface 22 (y direction), the second metal film 74 is formed to have an area larger than the area of ​​the first metal film 73 so as to cover the first metal film 73. Figure 6 Other characteristic examples are described below.

[0090] In the laser module 100 of the present embodiment, since the spacer film 72 is provided on the bonding surface 42 of the optical waveguide substrate 40, even if press-fitting is performed during the bonding process, the spacer S (see FIG. Figure 2) can also maintain a predetermined size. In the case where the metal film M1 is completely melted during the bonding process, the gap S becomes very small. In this case, the melted metal film M1 is squeezed out from the space between the laser element base 20 and the optical waveguide substrate 40. In contrast, in the laser module 100 of the present embodiment, the gap S is maintained at a thickness greater than the gap film 72 by providing the gap film 72, and as a result, the melted metal film M1 is suppressed from being squeezed out from the space between the laser element base 20 and the optical waveguide substrate 40.

[0091] When the metal films M1 and M2 are formed on the respective bonding surfaces, a seed layer is sometimes formed. Since the seed layer is very thin compared to the thickness of the metal films M1 and M2, when the optical waveguide substrate 40 and the laser element base 20 are heated and pressed into place, the gap between the optical waveguide substrate 40 and the laser element base 20 cannot be maintained, and the melted metal film M1 is squeezed out from between them.

[0092] The gap S between the laser element base 20 and the optical waveguide substrate 40 depends on the thickness of the spacer film and the amount of the metal films M1 and M2, and is about 0.2 μm to 1.2 μm as an example. The gap volume between the laser element base 20 and the optical waveguide substrate 40 can be determined based on the volume of the molten metal.

[0093] The thickness of the spacer film 72 can be determined based on the volume of the metal films M1 and M2. The volume of the metal films M1 and M2 is set such that the metal film M1 does not overflow from the space between the laser element base 20 and the optical waveguide substrate 40 when melted, and is the volume required to make the eutectic bonding between the laser element base 20 and the optical waveguide substrate 40 have the desired strength.

[0094] Examples of the material of the spacer film 72 include aluminum oxide (Al2O3), titanium oxide (TiO x ), tantalum oxide (TaO x ), silicon oxide (SiO x ) and other oxides, Ti, Ta and other metals.

[0095] Rare metals such as Ti and Ta can be used as materials for so-called seed films. Therefore, when the spacer film 72 is made of rare metals such as Ti and Ta, the material used is the same as that of the seed film. However, since the seed film is usually used with a thickness of about several tens of nm, in the case of the spacer film 72, in order to sufficiently ensure the spacing S, it is preferred that the thickness be set to be 0.1 μm or more, and more preferably 0.2 μm or more. By ensuring that the spacing S that can form the space (gap) between the laser element base 20 and the optical waveguide substrate 40 is maintained to a degree that the volume of the space (gap) is larger than the volume of the metal film M1 melted during bonding, the metal films M1 and M2 can be left in the space (gap).

[0096] In this case, from the viewpoint of material cost, the upper limit of the thickness of the spacer film 72 is approximately 0.4 μm.

[0097] On the other hand, when the spacer film 72 is made of an oxide such as aluminum oxide, the thickness of the spacer film 72 is preferably set to 0.1 μm or more, and more preferably to 0.2 μm or more, for the purpose of providing the spacer film 72, as in the case of being made of a rare metal. On the other hand, although the upper limit can be relaxed from the viewpoint of material cost, if it is too thick, deformation due to internal stress may be a concern, so the upper limit of the thickness of the spacer film 72 is preferably set to 1 μm, for example. It is preferable to select a material with low internal stress.

[0098] At least a portion of the first metal film 73 is disposed on the spacer film 72. The first metal films 73-1, 73-2, and 73-3 are disposed separately from each other.

[0099] By using the photomask used in forming the spacer film 72 (72-1, 72-2, 72-3) as it is when forming the first metal film 73 (73-1, 73-2, 73-3), each of the first metal films 73-1, 73-2, 73-3 having the same size as the spacer film can be stacked on each of the spacer films 72-1, 72-2, 72-3. In addition, by using a photomask having a smaller hole size than the photomask used in forming the spacer film 72 (72-1, 72-2, 72-3) when forming the first metal film 73 (73-1, 73-2, 73-3), the first metal film 73 having a smaller size than the spacer film 72 can be stacked.

[0100] Since the first metal film 73 is melted when the laser element base and the optical waveguide substrate are bonded, due to the difference in size between the first metal film 73 and the spacer film 72, a portion of the first metal film 73 is disposed not only on the spacer film 72 but also on the bonding surface 42 around the spacer film 72 (see Figure 5B , Figure 6).

[0101] The first metal film 73 is preferably made of Sn or an alloy containing Sn such as Sn—Ag—Cu (SAC).

[0102] The thickness of the first metal film 73 formed in advance on the spacer film 72 before being bonded to the laser element base can be set to about 0.2 μm to 0.6 μm, for example.

[0103] When forming the first metal film 73 on the spacer film 72, a seed film of a metal film selected from the group consisting of Ta, Ti, Ni, Ta / Pt, Ti / Pt and Ni / Pt can be used. Here, the metal film of Ta / Pt, Ti / Pt and Ni / Pt is a double-layer film of a Ta film, a Ti film or a Ni film and a Pt film, and the Pt film in the double-layer film is arranged on the side directly in contact with the first metal film 73. By inserting the Pt film, it can be expected that the bonding strength between the first metal film 73 and the seed film is enhanced. For example, from the viewpoint that the metal of the first metal film 73 does not flow out from the gap during bonding, it is preferred to form the first metal film 73 into a small area, but if the first metal film 73 becomes smaller, the bonding strength between it and the seed film is weakened. By inserting the Pt film, it can be expected that the decrease in bonding strength is suppressed.

[0104] Since the Sn film and the alloy film containing Sn do not form a eutectic alloy with the Ta film, Ti film, or Ni film, the interface between the Sn film and the Ta film, Ti film, or Ni film can be recognized by an electron microscope image, but peeling occurs at the interface during peeling. On the other hand, since the Sn film and the alloy film containing Sn form a eutectic alloy with the Pt film, there is a case where the interface between the Sn film and the alloy film containing Sn and the Pt film is not clear and cannot be recognized by an electron microscope image.

[0105] The second metal film 74 is preferably made of a metal that can form a eutectic alloy with Sn, for example, a metal selected from the group consisting of Au, Si, Al, Ni, Zn, Pt, and alloys thereof. The second metal film 74 is most preferably an Au film that forms a strong eutectic alloy with Sn.

[0106] The thickness of the second metal film 74 formed in advance on the bonding surface 22 of the laser element base 20 before bonding to the optical waveguide substrate 40 can be set to, for example, about 0.2 μm to 1.0 μm.

[0107] The second metal film 74 is formed to have a larger area than the spacer film 72 , and is formed to cover the spacer film 72 when viewed from a direction perpendicular to the film.

[0108] Preferably, the second metal film 74 is formed to have a larger area than the first metal film 73 , and is formed to cover the first metal film 73 when viewed from a direction perpendicular to the film.

[0109] Each film is formed before bonding the laser element base and the optical waveguide substrate. At this time, the second metal film 74 only needs to be formed in advance to have a larger area than the spacer film 72 and in advance to have a larger area than the first metal film 73 .

[0110] When forming the second metal film 74 on the bonding surface 22 of the laser element base 20, a seed film of a metal film selected from the group consisting of Ta, Ti, Ta / Pt and Ti / Pt can be used. Here, the metal film of Ta / Pt and Ti / Pt is a double-layer film of a Ta film or a Ti film and a Pt film, and the Pt film in the double-layer film is arranged on the side directly contacting the second metal film 74. By inserting the Pt film, it can be expected that the bonding strength between the second metal film 74 and the seed film will be enhanced.

[0111] Figure 6 The film structure of the metal laminate film 70 and the spacer film 72 constituting the junction is shown. Figure 5B Examples of different features of the construction shown.

[0112] Figure 6 The example shown is similar to Figure 5B The same point is that the metal film M1 disposed on the spacer film Sp is melted and then pressed into the laser element base 20, so that the metal film M1 is partially diffused to the bonding surface 42 around the spacer film Sp to form the first metal film 73, but Figure 5B The difference is that the second metal film 74 is formed to have an area substantially the same as that of the first metal film 73 .

[0113] Fig. 7A and Figure 7B The antireflection film 81 is provided on the bonding surface 42 of the optical waveguide substrate 40 . Fig. 7A , Figure 7B Respectively Figure 5B , Figure 6 In the case of this structure, the spacer film 72 is formed on the anti-reflection film 81 .

[0114] The anti-reflection film 81 is a film for preventing the incident light or the emitted light from the optical waveguide layer 50 from being reflected in the direction opposite to the direction from which the incident light or the emitted light enters the respective surfaces from the incident surface 50A or the emission surface 64, thereby improving the transmittance of the incident light or the emitted light. The anti-reflection film 81 is, for example, a multilayer film formed by alternately stacking a plurality of types of dielectrics with a predetermined thickness corresponding to the wavelengths of red light, green light, and blue light as the incident light. Examples of the dielectric include titanium oxide (TiO2), tantalum oxide (Ta2O5), silicon oxide (SiO2), and aluminum oxide (Al2O3).

[0115] The emission surface 30A of the laser element 30 and the incident surface 50A of the optical waveguide layer 50 are arranged at a predetermined interval. The incident surface 50A is opposite to the emission surface 30A, and there is a gap between the emission surface 30A and the incident surface 50A in the x direction. The size of the gap in the y direction is, for example, greater than 0 μm and less than or equal to 5 μm, based on the fact that the laser module 100 is used for XR glasses and the amount of light obtained by the XR glasses.

[0116] 〔Laser module〕

[0117] Figure 8 1 is a schematic plan view of the laser module according to the present embodiment. Fig. 9 Use XZ plane to Figure 8 The laser module shown is partially broken away to show a cross section of a laser unit arranged inside.

[0118] exist Figure 8 In the laser module 1000 shown, the laser assembly 100 of the above embodiment is disposed on the upper surface 180 a of the base 180 and is housed in the package 110 .

[0119] Preferably, in the laser module 100 housed in the package 110, the laser element base 20 and the optical waveguide substrate 40 are bonded so that the bottom surface 20b of the laser element base 20 and the bottom surface 43 of the optical waveguide substrate 40 are located on substantially the same plane. In the laser module 100, since the laser element base 20 and the optical waveguide substrate 40 are bonded by eutectic bonding of metals, the occurrence of misalignment due to the heating process is significantly suppressed compared to a structure bonded by an adhesive.

[0120] In addition, the substantially same plane mentioned here allows a slight deviation between the bottom surface 20b of the laser element base 20 and the bottom surface 43 of the optical waveguide substrate 40. Specifically, a deviation of 20 μm or less is allowed with respect to the thickness of the optical waveguide substrate 40 along the z direction, but the smaller the deviation, the better, more preferably 10 μm or less, and even more preferably 5 μm or less.

[0121] When the laser element base 20 and the optical waveguide substrate 40 are joined in such a manner that the bottom surface 20 b of the laser element base 20 and the bottom surface 43 of the optical waveguide substrate 40 are located on substantially the same plane with each other, the heat generated during the operation of the laser element 30 can be efficiently dissipated by utilizing both the bottom surface 20 b of the laser element base 20 and the bottom surface 43 of the optical waveguide substrate 40.

[0122] Furthermore, when the laser element base 20 and the optical waveguide substrate 40 are joined in such a manner that the bottom surface 20 b of the laser element base 20 and the bottom surface 43 of the optical waveguide substrate 40 are located on substantially the same plane with each other, since both the bottom surface 20 b of the laser element base 20 and the bottom surface 43 of the optical waveguide substrate 40 can be joined on one plane, which is the upper surface 180 a of the base 180, the joining strength can be maintained high, thereby realizing a laser component 100 with excellent impact resistance.

[0123] In this way, in a structure in which the laser element base 20 and the optical waveguide substrate 40 are bonded so that the bottom surface 20 b of the laser element base 20 and the bottom surface 43 of the optical waveguide substrate 40 are located on substantially the same plane, heat dissipation and impact resistance can be improved.

[0124] The package 110 may include not only the laser module of the above-described embodiment but also known components, such as a photoreceiver (photodetector: PD).

[0125] When a PD is included, the optical output variation of the laser element can be checked by observing the current flowing through the PD. In addition, the current flowing through the PD can be monitored to control the drive current of the laser element so that the output is constant.

[0126] The package body 110 includes a main body 102 having a cavity configuration and a cover 105 covering the main body 102 .

[0127] The main body 102 has a bottom portion on which components housed therein are placed, and a side wall portion 102 a arranged to surround these components from the side.

[0128] A light transmission window 101 is formed in the side wall portion 102 a arranged in the direction in which the laser light is emitted. The light transmission window 101 is capable of optically transmitting the laser light L emitted from the laser element 30 .

[0129] A light transmission window (opening) 101 is formed in the side wall portion 102a of the storage portion 107 near the emission portion of the laser L emitted from the laser module 1000. The opening 101 is formed with the position of the side wall portion 102a intersecting with the optical axis of the emitted laser as the approximate center. The opening 101 is covered by the glass plate 220 from the outside of the side wall portion 102a without a gap. In other words, the storage portion 107 is hermetically sealed by the glass plate 220 in addition to the cover 105. Although the glass plate 220 is used for airtight sealing, it is not limited to the glass plate as long as it is a material that can transmit laser light. An anti-reflection film not shown in the figure can also be provided on both plate surfaces of the glass plate 220.

[0130] The electrode portion 108 is arranged near the front side in the x direction of the storage portion 107, that is, at the rear in the x direction. The upper surface of the electrode portion 108 is located below the upper surface of the storage portion 107. The bottom surface of the electrode portion 108 is located at substantially the same height as the bottom surface of the storage portion 107. On the upper surface of the electrode portion 108, a plurality of external electrode pads 210 are provided at intervals in the y direction.

[0131] The bottom surface 20b of the laser element base 20 and the bottom surface 43 of the optical waveguide substrate 40 only need to be bonded to the upper surface 180a (one inner surface) of the base 180 via the adhesive layer 182. The adhesive layer 182 uses a material in which a filler is mixed in a resin to improve thermal conductivity. As a resin constituting the adhesive layer 182, for example, epoxy resin can be cited. In addition, as a filler that improves the thermal conductivity of the resin, copper powder, aluminum powder, aluminum oxide powder, etc. can be used.

[0132] In order to maintain a certain level of thermal conductivity, the adhesive layer 182 preferably has a thermal conductivity of 0.5 W / m·K or more, more preferably 1 W / m·K or more, and still more preferably 4 W / m·K or more.

[0133] In this way, by bonding the laser element base 20 and the optical waveguide substrate 40 of the laser module to the upper surface 180a of the base 180 in the package 110, the heat generated by the operation of the laser element 30 can be efficiently dissipated from the bottom surface 20b of the laser element base 20 and the bottom surface 43 of the optical waveguide substrate 40 toward the base 180. Furthermore, by bonding the bottom surface 20b of the laser element base 20 and the bottom surface 43 of the optical waveguide substrate 40 using an adhesive layer composed of a resin mixed with a filler, the heat can be efficiently transferred from the bottom surface 20b of the laser element base 20 and the bottom surface 43 of the optical waveguide substrate 40 toward the base 180.

[0134] Next, a case where the optical waveguide layer included in the laser module is composed of a lithium niobate film (LiNbO3) is described. In contrast to the quartz-based PLC described above, the optical waveguide layer in this case may be referred to as an LN-based PLC.

[0135] exist Fig.10 1 is a schematic plan view showing a state where a cover is removed from a laser module housing a laser unit, wherein the laser unit has an optical waveguide substrate including an optical waveguide layer composed of a lithium niobate film. Fig.11 Observed from the emission surface of the laser element Fig.10 A schematic top view of the laser assembly is shown.

[0136] There are cases where the same reference numerals are given to components common to the above-mentioned laser assembly and laser module, and description thereof is omitted. Fig.10 , in which a laser assembly includes a near-infrared laser element in addition to an RGB laser element as an example of a laser element. Since near-infrared laser is invisible, it can be used for eye tracking. The above-mentioned laser assembly may also be configured to include a near-infrared laser element.

[0137] exist Fig.10 In the laser module 2000 shown, the laser component 100B is housed in a package 110, and the laser component 100B includes a laser element 30 (30-1, 30-2, 30-3), a laser element base 20 (20-1, 20-2, 20-3) for respectively mounting the laser elements 30 (30-1, 30-2, 30-3), a near-infrared laser element 35, a laser element base 20-4 for mounting the near-infrared laser element 35, an optical waveguide substrate 140 having an LN-based PLC 150 formed on the main surface, and a joint portion, in which the joint surface of the laser element base 20 and the laser element base 20-4 and the joint surface of the optical waveguide substrate 140 are composed of a metal stacked film of a spacer film and a eutectic bond.

[0138] The near-infrared laser element 35 is mounted on the laser element base 20 - 4 similarly to the laser element 30 , and the LN-based PLC 150 is formed on the optical waveguide substrate 140 .

[0139] The laser module 2000 includes an LN-based PLC 150 in the package 110 . The LN-based PLC 150 includes an optical waveguide 151 ( 151 - 1 , 151 - 2 , 151 - 3 ) that guides the laser light emitted from the laser element 30 and an optical waveguide 152 that guides the near-infrared laser light emitted from the near-infrared laser element 35 .

[0140] In the laser module 2000 as well, the optical waveguide substrate 140 on which the LN-based PLC 150 is formed is eutectically bonded and integrated with the laser element base 20 on which the laser element 30 is mounted and the laser element base 20 - 4 on which the near-infrared laser element 35 is mounted.

[0141] This eutectic bonding enables accurate optical axis arrangement and also achieves miniaturization.

[0142] Examples of the optical waveguide substrate 140 include a sapphire substrate, a Si substrate, and a thermally oxidized silicon substrate.

[0143] When the optical waveguides 151 and 152 are formed of a lithium niobate (LiNbO3) film, there are no particular restrictions as long as the refractive index is lower than that of the lithium niobate film, but as a substrate capable of forming a single-crystal lithium niobate film as an epitaxial film, a sapphire single-crystal substrate or a silicon single-crystal substrate is preferred. The crystal orientation of the single-crystal substrate is not particularly limited, but for example, since the c-axis oriented lithium niobate film has a three-dimensional symmetry, it is desirable that the underlying single-crystal substrate also has the same symmetry, and in the case of a sapphire single-crystal substrate, a c-plane substrate is preferred, and in the case of a silicon single-crystal substrate, a (111)-plane substrate is preferred.

[0144] In the laser module 2000, the optical waveguide layer (LN-based PLC) 150 includes: an optical waveguide film 150A including an optical waveguide 151 and an optical waveguide 152; and a waveguide cladding film 150B formed on the optical waveguide film 150A in a manner of covering the optical waveguide 151 and the optical waveguide 152. The refractive index of the waveguide cladding film 150B is lower than the refractive index of the optical waveguide film 150A. The waveguide cladding film 150B is, for example, SiInO, SiO2, Al2O3, MgF2, La2O3, ZnO, HfO2, MgO, Y2O3, CaF2, In2O3, etc., or a mixture thereof.

[0145] The lithium niobate film (optical waveguide film 150A) is, for example, a c-axis oriented lithium niobate film. The lithium niobate film is, for example, an epitaxial film grown epitaxially on the optical waveguide substrate 140. An epitaxial film is a single crystal film whose crystal orientation is aligned using a base substrate. An epitaxial film is a film having a single crystal orientation in the z direction and the xy in-plane direction, and the crystals are aligned and oriented in the x-axis direction, the y-axis direction, and the z-axis direction. Whether the film formed on the optical waveguide substrate 140 is an epitaxial film can be proved by, for example, confirming the peak intensity and pole of the orientation position by performing 2θ-θ X-ray diffraction.

[0146] The composition of lithium niobate is Li x Nb y O z. A is an element other than Li, Nb, and O. x is greater than or equal to 0.5 and less than or equal to 1.2, preferably greater than or equal to 0.9 and less than or equal to 1.05. y is greater than or equal to 0 and less than or equal to 0.5. z is greater than or equal to 1.5 and less than or equal to 4.0, preferably greater than or equal to 2.5 and less than or equal to 3.5. Elements of A are, for example, K, Na, Rb, Cs, Be, Mg, Ca, Sr, Ba, Ti, Zr, Hf, V, Cr, Mo, W, Fe, Co, Ni, Zn, Sc, and Ce, and two or more of these elements may be combined.

[0147] The thickness of the lithium niobate film is, for example, 2 μm or less. The thickness of the lithium niobate film is the thickness of the portion excluding the ridge portion. If the thickness of the lithium niobate film is too thick, the crystallinity may be reduced.

[0148] The thickness of the lithium niobate film is, for example, about 1 / 10 or more of the wavelength of the light used. If the thickness of the lithium niobate film is thin, the confinement of light is weakened, and light leaks to the optical waveguide substrate 140 and the waveguide cladding film 150B.

[0149] The optical waveguide 151 and the optical waveguide 152 are paths for light to be transmitted inside. The optical waveguide 151 and the optical waveguide 152 are ridges protruding from the first surface 150AA of the planar layer 150Aa of the optical waveguide film 150A. Hereinafter, the optical waveguide 151-1, the optical waveguide 151-2, the optical waveguide 151-3, and the optical waveguide 152 are sometimes referred to as the ridge 151-1, the ridge 151-2, the ridge 151-3, and the ridge 152, respectively. The first surface 150AA is the upper surface of the portion (planar layer 150Aa) of the optical waveguide film 150A other than the ridge portion. The optical waveguide film 150A is composed of the ridges 151-1, 151-2, 151-3, 152, and the planar layer 150Aa.

[0150] Fig.11 The cross-sectional shape of the ridges 151-4 and 152 shown is a rectangle, but any shape that can conduct light may be used, for example, a trapezoid, a triangle, a semicircle, etc. The width Wa in the y direction is preferably 0.3 μm or more and 5.0 μm or less, and the height of the ridge (the protrusion height Ha protruding from the first surface 150AA) is preferably 0.1 μm or more and 1.0 μm or less, for example.

[0151] like Fig.10As shown, the optical waveguide 151-1, the optical waveguide 151-2, and the optical waveguide 151-3 are mutually combined into one optical waveguide on the front side of the emission surface reaching the optical waveguide layer 150. That is, the optical waveguide 151-1, the optical waveguide 151-2, and the optical waveguide 151-3 are successively combined as they go forward in the x direction, and are combined into one optical waveguide 151-4. In order to prevent light leakage from the optical waveguide 151-1, the optical waveguide 151-2, and the optical waveguide 151-3, the optical waveguide 151-1, the optical waveguide 151-2, and the optical waveguide 151-3 are preferably connected to the optical waveguide 151-4 with a curvature radius greater than a predetermined curvature radius.

[0152] like Fig.10 As shown, the red light, green light, and blue light emitted from the laser elements 30-1, 30-2, and 30-3 are transmitted in each ridge after being incident on each ridge 151-1, 151-2, and 151-3. The blue light and green light transmitted in the ridge 151-3 and the ridge 151-2 are combined at a predetermined confluence position 157-1 that is behind the confluence position 157-2 in the x direction. The combined blue light and green light are combined with the red light transmitted in the ridge 151-1 at the confluence position 157-2. The RGB light combined at the confluence position 157-2 is transmitted in the ridge 151-4, reaches the emission surface, and is emitted from the emission surface.

[0153] Furthermore, the near-infrared light emitted from the laser element 35 propagates through the ridge 152 , reaches the emission surface, and is emitted from the emission surface.

[0154] Each of the optical waveguides 151-1, 151-2, 151-3, and 152 included in the LN-based optical waveguide layer 150 may be a Mach-Zehnder optical waveguide, and in this case, a known Mach-Zehnder optical modulator such as an electrode (not shown) for applying an electric field to the optical waveguide is provided.

[0155] 〔XR glasses〕

[0156] The XR glasses of this embodiment include the laser module of the above-mentioned embodiment mounted on the glasses.

[0157] XR glasses (glass) are glasses-type terminals. XR is a general term for virtual reality (VR: Virtual Reality), augmented reality (AR: Augmented Reality), and mixed reality (Mixed Reality).

[0158] exist Fig.12 A conceptual diagram of XR glasses for illustrating the present embodiment is shown in FIG.

[0159] Fig.12The XR glasses 10000 shown in the figure have a laser module 1001 mounted on a frame 10010. Reference numeral L denotes image display light.

[0160] exist Fig.12 In this specification, the laser module 1001, the light scanning mirror 3001, and the optical system 2001 connecting the laser module 1001 and the light scanning mirror 3001 are collectively referred to as an optical engine 5001. As the laser module 1001, any of the laser modules of the above-described embodiments is used.

[0161] As the light source of the laser module 1001 , for example, a light source including RGB laser elements of a red laser element 30 - 1 , a green laser element 30 - 2 , and a blue laser element 30 - 3 and a near-infrared laser element 35 can be used.

[0162] As the light source of the laser module 1001 , for example, a light source including RGB laser elements of a red laser element 30 - 1 , a green laser element 30 - 2 , and a blue laser element 30 - 3 and a near-infrared laser element 35 can be used.

[0163] like Fig.13 As shown, the laser irradiated from the laser module 1001 installed on the eyeglass frame is reflected by the light scanning reflector 3001, and its reflected light is reflected by the reflector 4001 that reflects in the direction of the human eyeball E, enters the human eyeball E, and can directly project an image (image) onto the retina M.

[0164] By including an eye tracking mechanism, an image can be directly projected onto the retina while performing eye tracking. As the eye tracking mechanism, a known mechanism can be used.

[0165] The light scanning mirror 3001 is, for example, a MEMS mirror. In order to project a 2D image, it is preferably a two-axis MEMS mirror that vibrates so as to reflect laser light while changing angles in the horizontal direction (X direction) and the vertical direction (Y direction).

[0166] The optical system 2001 for optically processing the laser light emitted from the laser module 1001 includes a collimator lens 2001a, a stop 2001b, and an ND filter 2001c. This optical system is an example, and other configurations are also possible.

[0167] The optical engine 5001 includes a laser driver 1100, a light scanning mirror driver 1200, and a video controller 1300 for controlling these drivers.

[0168] [Manufacturing method of laser component]

[0169] exist Figures 14A to 14CA flowchart of an example of a method for manufacturing a laser module is shown in FIG.

[0170] The method for manufacturing a laser module includes a step of manufacturing an optical waveguide substrate, a step of manufacturing a laser element base, and a step of bonding the optical waveguide substrate and the laser element base obtained in the respective steps.

[0171] like Fig.14A As shown, in the optical waveguide substrate manufacturing process, a plurality of optical waveguide layers are first formed on a wafer. The plurality of optical waveguide layers are optical waveguide layers ( Figure 1 The optical waveguide layer 50).

[0172] Next, the wafer is diced to cut out a plurality of optical waveguide substrate rod members having optical waveguide layers on their main surfaces. The plurality of optical waveguide substrate rod members cut out can each include the optical waveguide layers in the number obtained by dividing the total number of laser modules to be obtained from the wafer by the number of optical waveguide substrate rod members.

[0173] Next, a stacked film of a spacer film and a first metal film is formed on the joint surface of each optical waveguide substrate rod member using a photolithography technique. Specifically, a plurality of optical waveguide substrate rod members are arranged, and films are simultaneously formed on the joint surfaces of these optical waveguide substrate rod members using a photoresist mask having a plurality of holes corresponding to the patterns of a plurality of spacer films disposed separately from each other, and the spacer film and the first metal film are sequentially formed, and a stacked film of the spacer film and the first metal film is formed for each hole.

[0174] like Fig. 14B As shown, in the laser element base manufacturing process, first, a wafer is diced to cut out a plurality of laser element base rod members.

[0175] Next, a plurality of rod members for laser element bases are arranged, and the second metal film is simultaneously formed on each joint surface. At this time, the second metal film may be formed on the entire joint surface of each rod member for laser element bases, or may be formed on a smaller area than the joint surface. Since the rod member for laser element bases is later cut into laser element bases for each laser element, the second metal film may be formed as a continuous film for each rod member for laser element bases.

[0176] Next, a plurality of laser elements are provided on the main surface of each laser element base rod member.

[0177] Next, each laser element base rod member is cut into laser element bases corresponding to the respective laser elements.

[0178] like Fig. 14CAs shown, the laser element base produced in the laser element base producing step is individually joined to the joining surface of the optical waveguide substrate rod member produced in the optical waveguide substrate producing step.

[0179] Active calibration bonding can be used for bonding. Specifically, current is supplied to an electrode provided on a laser element base, and the laser is oscillated in a state of being electrically connected to the laser element. In this state, the position is adjusted while approaching the entrance of the optical waveguide path of the optical waveguide substrate rod member. Then, the light intensity is observed at the exit using a light sensor, and the position where the intensity is the highest is found, and the laser element base and the optical waveguide substrate rod member are eutectic bonded at this position. Eutectic bonding can be implemented, for example, by irradiating a YAG laser to melt the metal formed on the bonding surface.

[0180] Next, after all the laser element bases are bonded to each laser element base, the optical waveguide substrate rod members are cut for each laser module.

[0181] This completes the laser assembly.

Claims

1. A laser assembly, characterized in that: The laser assembly includes: Multiple laser elements; A base for a plurality of laser elements, which has a main surface and a bonding surface, wherein the plurality of laser elements are respectively arranged on the main surface; an optical waveguide substrate having a main surface and a bonding surface, wherein an optical waveguide layer having an optical waveguide is provided on the main surface of the optical waveguide substrate, the optical waveguide guiding the laser beams emitted from the plurality of laser elements; a plurality of spacer films which are arranged at positions on the bonding surface of the optical waveguide substrate corresponding to the plurality of laser element bases in a one-to-one manner; and a plurality of metal laminated films that bond the bonding surfaces of the plurality of laser element bases and the bonding surface of the optical waveguide substrate, The plurality of metal stacked films include a plurality of first metal films and a second metal film, the plurality of first metal films being respectively arranged on the plurality of spacer films, and the second metal film being arranged on the bonding surface of the plurality of laser element bases and being composed of a metal that can form a eutectic with the metal constituting the first metal film.

2. The laser assembly according to claim 1, characterized in that The first metal film is composed of Sn or an alloy containing Sn, and the second metal film is composed of a metal selected from the group consisting of Au, Si, Al, Ni, Zn, Pt, and alloys thereof.

3. The laser assembly according to claim 1, characterized in that The spacer film has a thickness of 0.1 μm or more.

4. The laser assembly according to claim 1, characterized in that The spacer film is made of a metal selected from the group consisting of Ta, Ti, Ni, Ta / Pt, Ti / Pt, and Ni / Pt.

5. The laser assembly according to claim 1, characterized in that The spacer film is made of oxide.

6. The laser assembly according to claim 1, characterized in that The second metal film is formed to have a larger area than the first metal film.

7. The laser assembly according to claim 1, characterized in that An antireflection film is provided on the bonding surface of the optical waveguide substrate, and the spacer film is formed on the antireflection film.

8. The laser assembly according to any one of claims 1 to 7, characterized in that: The optical waveguide layer is a planar lightwave circuit made of glass material.

9. The laser assembly according to any one of claims 1 to 7, characterized in that: The optical waveguide layer is a planar lightwave circuit composed of a lithium niobate film.

10. A laser module, characterized in that: The laser assembly according to claim 8 is housed in a package.

11. A laser module, characterized in that: The laser module according to claim 9 is housed in a package.

12. An optical engine, characterized in that: The optical engine includes: The laser module according to claim 10; and A light scanning mirror scans the light emitted from the laser module.

13. An optical engine, characterized in that: The optical engine includes: The laser module according to claim 11; and A light scanning mirror scans the light emitted from the laser module.

14. An extended reality glasses, characterized in that: The extended reality glasses include the optical engine described in claim 12.

15. An extended reality glasses, characterized in that: The extended reality glasses include the optical engine described in claim 13.

16. A method for manufacturing a laser component, characterized in that: The manufacturing method has the following steps: an optical waveguide substrate manufacturing step in which a plurality of spacer films and a first metal film are sequentially formed on a bonding surface of the optical waveguide substrate; a laser element base manufacturing step of forming a second metal film on a bonding surface of the laser element base; and A bonding step is performed after the optical waveguide substrate manufacturing step and the laser element base manufacturing step, and in this bonding step, the laser element base and the optical waveguide substrate are eutectically bonded.

17. The method for manufacturing a laser component according to claim 16, characterized in that: In the optical waveguide substrate manufacturing step, the spacer film and the first metal film are formed using a photoresist mask having a plurality of holes corresponding to patterns of a plurality of the spacer films provided separately from each other on the bonding surface of the optical waveguide substrate. In the bonding step, the first metal film of the optical waveguide substrate and the second metal film of the laser element base are eutectic bonded using active alignment bonding.

Images