Optical element assembly, method for manufacturing an optical element assembly, optical module, optical engine, and XR glasses

Abstract

The present invention provides a method for manufacturing optical element assemblies that enables high-precision alignment even when the elements are miniaturized. [Solution] An optical element assembly comprising a plurality of laser diodes and an optical waveguide layer having an optical waveguide for guiding the laser light emitted from the plurality of laser diodes, wherein the optical waveguide layer has alignment markers, the alignment markers are provided on the outermost surface of the optical waveguide layer and are located inward from the outer edge of the optical waveguide layer.

Description

Technical Field

[0001] The present invention relates to an optical element assembly, a method for manufacturing the optical element assembly, an optical module, an optical engine, and XR glasses.

Background Art

[0002] Optical element assemblies for XR glasses, such as AR (Augmented Reality) glasses and VR (Virtual Reality) glasses that have a plurality of laser diodes, are expected to be compact wearable devices. For wearable devices such as AR glasses and VR glasses, miniaturization to fit all functions into a normal eyeglass-type size is the key to widespread adoption.

[0003] As an optical element assembly, a configuration in which a light-emitting assembly on which a light-emitting element is formed and an optical waveguide assembly on which an optical waveguide is formed are joined is known (for example, Patent Document 1). In Patent Document 1, in order to align the position of the active layer of the light-emitting element with the optical waveguide, a protrusion is provided on the light-emitting element assembly, and a groove that fits with the protrusion of the light-emitting element assembly is provided on the optical waveguide assembly.

[0004] The optical element assembly of Patent Document 1 is described as having a configuration in which the active layer and the optical waveguide are aligned when the protrusion of the light-emitting element assembly and the groove of the optical waveguide assembly are fitted together.

Prior Art Literature

Patent Documents

[0005]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0006] However, in the optical element assembly described in Patent Document 1, alignment is achieved through the shaping of two components. However, the shaping of protrusions and grooves has limitations in meeting the recent miniaturization of optical element assemblies, and other means for aligning the light-emitting element and waveguide are needed. In addition, some optical element assemblies have been designed to provide alignment markers on the surface where the waveguide outlet is located. However, when alignment markers are provided on the surface where the waveguide outlet is located, the optical waveguide layer on which the optical waveguide is provided has been miniaturized along with the miniaturization of the optical element assembly, so the alignment markers need to be made smaller. However, if the alignment markers are made smaller, they are difficult to find when observing from the exit surface side of the optical waveguide, which limits the ability to meet the miniaturization requirements.

[0007] The present invention has been made in view of the above circumstances, and aims to provide an optical element assembly that can be aligned with high precision even when the elements are miniaturized, a method for manufacturing an optical element assembly that can be aligned with high precision even when the elements are miniaturized, an optical module equipped with the optical element assembly, an optical engine, and XR glasses. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides the following means.

[0009] [1] An optical element assembly according to one aspect of the present invention comprises a laser diode and The device comprises an optical waveguide layer having an optical waveguide for guiding laser light emitted from the laser diode, wherein the optical waveguide layer has alignment markers, the alignment markers are provided on the outermost surface of the optical waveguide layer and are located inward from the outer edge of the optical waveguide layer.

[0010] In the optical element assembly of [2][1], the alignment marker may be a metal film.

[0011] In the optical element assemblies of [3] [1] and [2], the metal film may be an Au film or a Ta film.

[0012] In the optical element assemblies of [4][1] to [3], the alignment marker may be a recess.

[0013] The optical element assemblies of [5][1] to [4] may further include a base on which the laser diode is mounted on the main surface, an optical waveguide substrate on which the optical waveguide layer is provided on the main surface, and a plurality of metal films that join the base and the optical waveguide substrate.

[0014] The optical element assemblies of [6][1] to [5] include a plurality of laser diodes, and the base is composed of a plurality of bases, on which a laser diode may be mounted.

[0015] In the optical element assemblies of [7][1] to [6], the base and the optical waveguide substrate are Si substrates, and the core of the optical waveguide layer may be composed of SiO2.

[0016] In the optical element assemblies of [8][1] to [7], the base and the optical waveguide substrate are SiO2 substrates, and the core of the optical waveguide layer may be made of SiN.

[0017] In the optical element assemblies of [9][1] to [8], the base and the optical waveguide substrate are sapphire substrates, and the core of the optical waveguide layer may be composed of LiNbO3.

[0018]

[10] An optical module according to one aspect of the present invention may contain any of the optical element assemblies [1] to [9] within a package.

[0019]

[11] An optical engine according to one aspect of the present invention comprises the light source module of

[10] , and an optical scanning mirror that reflects light emitted from the light source module while changing the angle thereof to display an image.

[0020]

[12] XR glasses according to one aspect of the present invention are mounted with the optical engine of

[11] .

[0021]

[13] A method for manufacturing an optical element assembly according to one aspect of the present invention includes a bonding step of bonding a laser diode assembly to an optical waveguide chip on which an optical waveguide layer having alignment markers is formed, wherein the alignment markers are provided at positions inward from an outer peripheral edge on the outermost surface of the optical waveguide layer, and in the bonding step, the laser diode assembly is bonded to the optical waveguide chip while performing alignment by observing the optical waveguide layer in plan view.

[0022]

[14] The method for manufacturing an optical element assembly of

[13] further includes a dicing step and an alignment marker forming step before the bonding step, wherein in the dicing step, the optical waveguide substrate on which the optical waveguide layer is formed is diced to form the optical waveguide chip, and in the alignment marker forming step, the alignment markers are formed on the optical waveguide chip.

[0023]

[15] The method for manufacturing an optical element assembly of

[13] and

[14] further includes a bar cutting step and an alignment marker forming step before the bonding step, and further includes a dicing step after the bonding step, wherein in the bar cutting step, a bar member for optical waveguide is cut out from the wafer of the optical waveguide substrate on which the optical waveguide layer is formed, in the alignment marker forming step, the alignment markers are formed on the bar member for optical waveguide, and in the dicing step, the bar member for optical waveguide to which a plurality of the laser diode assemblies are bonded may be diced.

[0024] The method for manufacturing the optical element assembly according to any one of

[16] and

[13] to

[15] may include forming a thin film of gold or tantalum on the optical waveguide layer in the alignment marker forming step. [Advantageous Effects of Invention]

[0025] According to the present invention, which has been made in view of the above circumstances, it is possible to provide an optical element assembly that is accurately aligned even when elements are miniaturized, a method for manufacturing an optical element assembly that enables high-precision alignment even for miniaturized elements, an optical module including the optical element assembly, an optical engine, and XR glasses. [Brief Description of Drawings]

[0026] [Figure 1] 1 is a perspective view showing an example of the configuration of an optical element assembly according to an embodiment of the present invention. [Figure 2] 2 is a plan view of the optical element assembly of FIG. 1. [Figure 3] 3 is a cross-sectional view taken along line A-A' of the optical element assembly shown in FIG. 1. [Figure 4] FIG. 4(a) is a perspective view of a plurality of laser diode assemblies in FIG. 1, and FIG. 4(b) is a perspective view of the optical waveguide substrate in FIG. 1. [Figure 5] FIGS. 5(a) and 5(b) are cross-sectional views showing modified examples of the structure of an optical waveguide substrate and an optical waveguide layer on which alignment markers usable in an optical element assembly according to an embodiment of the present invention are formed. [Figure 6] FIG. 6(a) is a plan view showing an example of the configuration of an optical waveguide chip that can be used in the method for manufacturing an optical element assembly according to an embodiment of the present invention, and FIG. 6(b) is a side view of the optical waveguide chip observed from the side. [Figure 7] FIG. 7 is a schematic diagram for explaining the configuration of the method for manufacturing an optical element assembly according to an embodiment of the present invention, and is a perspective view showing a state of the bonding step. [Figure 8]This is a schematic diagram illustrating the configuration of a manufacturing method for an optical element assembly according to one embodiment of the present invention, and is a cross-sectional view showing the bonding process. [Figure 9] Figure 9(a) and a modified example of the method for manufacturing an optical element assembly according to one embodiment of the present invention are shown. [Figure 10] This is a plan view showing an example of the configuration of an optical module according to one embodiment of the present invention. [Figure 11] Figure 10 is a cross-sectional view of the optical module. [Figure 12] Figure 10 is a plan view illustrating the internal configuration of the optical module within the package. [Figure 13] Figure 12 is a schematic plan view of the configuration as seen from the emission surface. [Figure 14] This is a conceptual diagram illustrating an XR glasses relating to one embodiment of the present invention. [Figure 15] This is a conceptual diagram showing how an image is projected directly onto the retina by laser light emitted from an optical module according to one embodiment of the present invention. [Modes for carrying out the invention]

[0027] The embodiments will be described in detail below, with reference to the figures as appropriate. The drawings used in the following description may be enlarged for convenience to clearly illustrate the features, and the dimensional ratios of each component may differ from those in reality. The materials, dimensions, etc., exemplified in the following description are examples only, and the present invention is not limited to them. It is possible to modify and implement the invention as appropriate within the scope of achieving its effects.

[0028] [Optical element assembly] An optical element assembly according to one embodiment of the present invention comprises a laser diode and an optical waveguide layer having an optical waveguide for guiding laser light emitted from the laser diode, wherein the optical waveguide layer has alignment markers, which are provided on the outermost surface of the optical waveguide layer and are located inward from the outer edge of the optical waveguide layer.

[0029] Figure 1 is a perspective view showing an example of the configuration of an optical element assembly according to one embodiment of the present invention. Figure 2 is a plan view of the optical element assembly of Figure 1. Figure 3 is a cross-sectional view of the optical element assembly shown in Figure 1 along line AA'.

[0030] The optical element assembly shown in Figures 1 to 3 comprises, for example, a plurality of laser diode assemblies 3 (3-1, 3-2, 3-3) as laser diodes, and an optical waveguide substrate 40 on its main surface having an optical waveguide layer 50 having an optical waveguide 51 for guiding the laser light emitted from the plurality of laser diode assemblies 3. Figures 1 to 3 show an example in which three laser diode assemblies are formed, but the present invention is not limited to this example.

[0031] In this embodiment, when a component indicated by reference numeral ○ is described in a manner that distinguishes it from components indicated by reference numeral ○-1, ○-2, and ○-3, the reference numerals ○-1, ○-2, and ○-3 are used to distinguish and explain each component. However, for features common to all components, only reference numeral ○ is used, and the components are described collectively. In this embodiment, the base 20 is also referred to as a subcarrier. The laser diode 30 is also referred to as a laser diode.

[0032] The optical element assembly 100 shown in Figure 1 comprises three laser diodes 30, three bases 20 (20-1, 20-2, 20-3) on which each of the three laser diodes 30 is mounted on a main surface 21-1, 21-2, 21-3 and spaced apart from each other, an optical waveguide layer 50 having at least an optical waveguide 51 for guiding the laser light emitted from the three laser diodes 30 (30-1, 30-2, 30-3), an optical waveguide substrate 40 on which the optical waveguide layer 50 is provided on the main surface, and bases 20 (20-1, The bases 20-2, 20-3) and the optical waveguide substrate 40 are joined by a metal film M, the metal film M (72, 73, 74) is placed between the base-side joining surfaces 22 (22-1, 22-2, 22-3) of the base 20 (20-1, 20-2, 20-3) and the joining surface 42 of the optical waveguide substrate 40, with the metal film M (72, 73, 74) being placed between the base-side joining surfaces 22 (22-1, 22-2, 22-3) of the base 20 (20-1, 20-2, 20-3) and the optical waveguide substrate 40, respectively, and spaced apart from each other, thereby joining the bases 20-1, 20-2, 20-3 and the optical waveguide substrate 40.

[0033] <Laser diode and base for laser diode> In the optical element assembly 100 shown in Figure 1, the laser diodes 30-1, 30-2, and 30-3 are a laser diode that emits red light, a laser diode that emits green light, and a laser diode that emits blue light, respectively. The laser diodes 30-1, 30-2, and 30-3 can each be mounted on individual bases 20-1, 20-2, and 20-3 as, for example, bare chips (unpackaged chips). Subcarriers 20-1, 20-2, and 20-3 are composed of, for example, aluminum nitride (AlN) and silicon (Si).

[0034] A first metal layer 75 and a second metal layer 76 are provided between the subcarrier 20 and the laser diode 30 (see Figure 3). The subcarrier 20 and the laser diode 30 are connected via the first metal layer 75 and the second metal layer 76. While known methods can be used to form the first metal layer 75 and the second metal layer 76, known techniques such as sputtering, vapor deposition, and coating of paste-formed metal are available. The first metal layer 75 and the second metal layer 76 may consist of one or more metals selected from the group consisting of, for example, 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.

[0035] <Optical waveguide layer and optical waveguide substrate> As shown in Figures 1 to 3, the optical waveguide layer 50 is formed on the optical waveguide substrate 40. In this embodiment, a structure in which optical waveguide substrates 40 are stacked on top of each other may be referred to as an optical waveguide chip 45. Examples of optical waveguide substrates 40 include sapphire substrates, Si substrates, and thermal silicon oxide substrates. When the optical waveguide of the optical waveguide layer 50 is formed with a lithium niobate (LiNbO3) film, the substrate is not particularly limited as long as it has a lower refractive index than the lithium niobate film, but a sapphire single crystal substrate or a silicon single crystal substrate is preferred as a substrate on which a single crystal lithium niobate film can be formed as an epitaxial film. The crystal orientation of the single crystal substrate is not particularly limited, but for example, a c-axis oriented lithium niobate film has threefold symmetry, so it is desirable that the underlying single crystal substrate also has the same symmetry. 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.

[0036] The optical waveguide layer 50 has at least an optical waveguide that guides the laser light emitted from the laser diode. There are no particular restrictions on this optical waveguide layer; for example, known configurations can be used. Examples of optical waveguide layers are shown below.

[0037] The optical waveguide layer 50 is referred to as a PLC (Planar lightwave circuit). Furthermore, the optical waveguides 51-1, 51-2, and 51-3 are sometimes referred to as cores 51-1, 51-2, and 51-3.

[0038] The optical waveguide layer 50 is defined by an incident surface 50A located on the laser diode assembly 3 side, an exit surface 50B facing the incident surface 50A, and side surfaces 50C and 50D connecting the incident surface 50A and the exit surface 50B. In this embodiment, the incident surface 50A, the exit surface 50B, and the side surfaces 50C and 50D may be collectively referred to as the outer peripheral edge. The optical element assembly 100 according to this embodiment has an alignment marker AM located on the outermost surface of the optical waveguide layer 50 and inward from the outer peripheral edge of the optical waveguide layer 50. Here, "inward from the outer peripheral edge of the optical waveguide layer 50" means that the alignment marker AM does not come into contact with any of the incident surface 50A, the exit surface 50B, or the side surfaces 50C and 50D. The alignment marker AM is provided at a distance of, for example, 50 μm or more from the incident surface 50A, the exit surface 50B, and the side surfaces 50C and 50D.

[0039] As described above, the alignment marker AM is provided on the outermost surface of the optical waveguide layer 50. Therefore, even when the optical element assembly 100 is miniaturized, its size can be increased compared to when it is formed on the exit surface 50B or the incident surface 50A, where miniaturization is highly demanded. The alignment marker AM is located outside in the width direction of any of the cores 51-1 to 51-3 formed in the optical waveguide layer 50, and is located on the incident surface 50A side of the confluence position 57-1. More specifically, an example is shown in which the end of the alignment marker AM on the exit surface 50B side is located on the incident surface 50A side of the midpoint between the incident surface 50A and the confluence position 57-1.

[0040] The distances between the alignment marker AM and the respective entrance ports 51A-1, 51A-2, and 51A-3 of the cores 51-1, 51-2, and 51-3 in the x, y, and z directions are precisely known. By observing the optical waveguide layer 50 in a plan view, the coordinate positions of the alignment marker AM can be determined, thereby allowing for the determination of the coordinate positions of the entrance ports 51A-1, 51A-2, and 51A-3. Furthermore, determining the coordinate positions of the alignment marker AM by observing the optical waveguide layer 50 in a plan view includes a configuration in which the optical waveguide layer 50 is observed in a plan view while simultaneously being observed from other directions, as will be described in detail later using Figure 7.

[0041] From the viewpoint of ease of detection, the area of ​​the alignment marker AM when the optical waveguide layer 50 is viewed in plan view is preferably 20 μm or more in pattern width. The shape of the alignment marker AM can be arbitrarily set, but Figures 1 and 2 show an L-shaped structure consisting of a rectangle extending in the x-direction where multiple laser diode assemblies 3 are lined up and a rectangle extending in the y-direction, which is the direction from the incident surface 50A to the exit surface 50B. That is, all the sides constituting the alignment marker AM shown in Figures 1 and 2 are parallel to either the incident surface 50A, the exit surface 50B, or the sides 50C, 50D. With such a structure, the alignment marker AM is easy to detect, and the relative positional relationship with the cores 51-1, 51-2, and 51-3 can be easily detected. Thus, it is preferable that the alignment marker AM is composed of sides parallel to either the incident surface 50A, the exit surface 50B, or the sides 50C, 50D.

[0042] The alignment marker AM is, for example, a metal film. Any metal film that is resistant to oxidation is acceptable, but it is preferably an Au film mainly composed of gold, a Ta film mainly composed of tantalum, a Ni film mainly composed of nickel, or a Ti film mainly composed of titanium, with Au or Ta being preferred. The metal film may also be composed of an alloy of the above metal elements. In this embodiment, "main component" means 50 wt% or more in the metal film, and it is preferably 90 wt% or more or 99 wt% or more.

[0043] The alignment marker AM only needs to be located on the outermost surface of the optical waveguide layer 50. That is, as long as no other members are provided on the alignment marker AM in the stacking direction of the optical waveguide layer 50, it may be formed as a metal film directly on the flat optical waveguide layer 50 as shown in Figures 1 and 2, or it may be formed after removing the region on the optical waveguide layer 50 in which the alignment marker AM is provided, so that the entire surface of the optical waveguide chip 45 in the z direction is flat, or it may be formed after removing the region on the optical waveguide layer 50 in which the alignment marker AM is provided, so that only the region on the optical waveguide chip 45 in which the alignment marker AM is located is recessed.

[0044] The optical waveguide layer 50 is formed on the optical waveguide substrate 40, and as described above, the laser diode 30 is mounted on the subcarrier 20. The optical waveguide substrate 40 and the subcarrier 20 are integrated by a metal joint. This metal joint enables precise optical axis alignment and also allows for miniaturization.

[0045] The optical waveguide layer 50 is fabricated on the upper surface 41, integrally with the optical waveguide substrate 40, by semiconductor processes including known photolithography and dry etching used when forming fine structures such as integrated circuits. As shown in Figure 2, the optical waveguide layer 50 is provided with the same number of cores 51-1, 51-2, 51-3 as the laser diodes 30-1, 30-2, 30-3, and a cladding 52 surrounding the cores 51-1, 51-2, 51-3. The thickness of the cladding 52 and the width dimensions of the cores 51-1, 51-2, 51-3 are not particularly limited. For example, cores 51-1, 51-2, 51-3 with width dimensions of several microns are arranged in a cladding 52 with a thickness of about 50 μm.

[0046] Cores 51-1, 51-2, 51-3 and cladding 52 are made of, for example, quartz. Hereinafter, this will be referred to as quartz-based PLC. The refractive index of cores 51-1, 51-2, and 51-3 is higher than that of cladding 52 by a predetermined value. As a result, light incident on each of cores 51-1, 51-2, and 51-3 propagates through each core while undergoing total internal reflection at the interface between each core and cladding 52. Cores 51-1, 51-2, and 51-3 are doped with impurities such as germanium (Ge) in an amount corresponding to the aforementioned predetermined value.

[0047] As shown in Figures 1 to 3, cores 51-1, 51-2, and 51-3 are brought together into one just before reaching the exit port 64 of the optical waveguide layer 50. That is, cores 51-1, 51-2, and 51-3 merge sequentially as they move forward in the x-direction, and merge into a single core 51-4. To prevent light leakage from cores 51-1, 51-2, and 51-3, it is preferable that each of cores 51-1, 51-2, and 51-3 is connected to core 51-4 with a radius of curvature greater than or equal to a predetermined radius of curvature.

[0048] Cores 51-1 to 51-3 are composed of a material with a higher refractive index than the cladding that constitutes the regions of the optical waveguide layer 50 other than cores 51-1 to 51-4. The cladding is, for example, SiInO, SiO2, Al2O3, MgF2, La2O3, ZnO, HfO2, MgO, Y2O3, CaF2, In2O3, or mixtures thereof. The core is composed of, for example, lithium niobate, SiO2, SiN, etc. The composition of lithium niobate is Li x NbA y O z The formula is as follows: A is an element other than Li, Nb, or O. x is between 0.5 and 1.2, preferably between 0.9 and 1.05. y is between 0 and 0.5. z is between 1.5 and 4.0, preferably between 2.5 and 3.5. The 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.

[0049] Through a metal junction between the optical waveguide substrate 40 and the subcarriers 20, the optical axes of the optical waveguide layers 50 are precisely aligned so that the center of the entrance of each core 51-1, 51-2, 51-3 of the optical waveguide layer 50 almost coincides with the optical axis of the light emitted from the corresponding laser diodes 30-1, 30-2, 30-3, with each core and its corresponding laser diode positioned opposite each other.

[0050] As shown in Figure 3, the incident surface 50A of the optical waveguide layer 50 is positioned to face the exit surface 31 of the laser diode 30. More specifically, the exit surface 31-1 of the laser diode 30-1 faces the incident port 51A-1 of the optical waveguide 51-1. In the x and z directions, the optical axis of the red light emitted from the laser diode 30-1 and the center of the incident port 51A-1 approximately coincide. Similarly, the exit surface 31-2 of the laser diode 30-2 faces the incident port 51A-2 of the optical waveguide 51-2. In the x and z directions, the optical axis of the green light emitted from the laser diode 30-2 and the center of the incident port 51A-2 approximately coincide. The exit surface 31-3 of the laser diode 30-3 faces the incident port 51A-3 of the optical waveguide 51-3. In the x and z directions, the optical axis of the blue light emitted from the laser diode 30-3 and the center of the entrance port 51A-3 substantially overlap. With this configuration and arrangement, at least a portion of the red, green, and blue light emitted from the laser diodes 30-1, 60-2, and 60-3 can be incident on the optical waveguides 51-1, 51-2, and 51-3.

[0051] As shown in Figure 2, the red, green, and blue light emitted from the laser diodes 30-1, 30-2, and 30-3 are incident on cores 51-1, 51-2, and 51-3, respectively, and then propagate through each core. The red and green light propagating through cores 51-3 and 51-2 are combined at a predetermined confluence point 57-1 located behind confluence point 57-2 in the y-direction. The combined red and green light and the blue light propagating through 51-2 combine at confluence point 57-2. The RGB light combined at confluence point 57-2 propagates through core 51-4, reaches the output port 64, and is emitted from the output port 64.

[0052] Figure 4(a) shows an enlarged view of the configuration of the laser diode 30 formed on the base 20. The laser diode 30 is formed on the base 20 together with an active layer 35 corresponding to the emission part and electrode parts such as the cathode and anode that are electrically connected to the active layer 35. In Figure 4(a), the widthwise centers of the emission part are indicated by the symbols C30-1 to C30-3. For alignment in the x-direction, the widthwise centers C30-1 to C30-3 are aligned with the entrance ports 51A-1 to 51A-3.

[0053] <Joint part> The three individual bases 20-1, 20-2, and 20-3 and the optical waveguide substrate 40 are joined via a metal film M. Figure 4(b) shows a perspective view of the optical waveguide substrate 40. The metal film M is placed between the base-side joining surfaces 22-1, 22-2, and 22-3 of the three individual bases 20-1, 20-2, and 20-3, and the three substrate-side joining portions 42-1, 42-2, and 42-3 on the joining surface 42 of the optical waveguide substrate 40, which are spaced apart from each other and correspond to the base-side joining surfaces 22-1, 22-2, and 22-3. By placing the metal film M only on the spaced-apart substrate-side joining portions 42-1, 42-2, and 42-3, and by having a separated film rather than a continuously formed film, the occurrence of capacitive coupling is suppressed and crosstalk is prevented.

[0054] For convenience, the metal film M shown in Figures 2 and 3 is depicted as a three-layer structure, reflecting the fabrication process of the metal film M (or, more precisely, the bonding process between the base and the optical waveguide substrate). Furthermore, when describing the metal film M, each of the three layers may also be explained individually. In other words, for convenience, the metal film M shown in the figure is depicted as consisting of three layers: a first metal film 74 (74-1, 74-2, 74-3) placed on the base-side bonding surfaces 22-1, 22-2, 22-3 of the individual bases 20-1, 20-2, 20-3; a second metal film 72 (72-1, 72-2, 72-3) placed on the substrate-side bonding portions 42 of the optical waveguide substrate 40, which are spaced apart from each other and correspond to the base-side bonding surfaces 22-1, 22-2, 22-3; and a eutectic layer 73 placed between the first metal film 74 and the second metal film 72. In actual bonding, if the first and second metal films are sufficiently thin, an alloy layer (eutectic layer) is formed, and the first and second metal films do not remain. On the other hand, if either the first or second metal film is thick, the thicker metal film may eutectic only on the surface side, leaving the base side or optical waveguide substrate side intact, while the other metal film may eutectic completely. However, it becomes difficult to clearly distinguish between the layers (distinguish between interfaces). Thus, in actual bonding, the film structure of the metal film M differs depending on the conditions of the metal film M fabrication process, and the figure conceptually depicts the characteristic surfaces of the film structure. For example, the structure may be one or both of the first metal film 74 and the second metal film 72 remaining relatively intact, or the entirety of the first metal film 74 and the second metal film 72 may be alloyed to form a eutectic layer.

[0055] The first metal film 74 is formed, for example, over the entire joining surface 22 of the base 20, or over the entire surface except for the edges. The first metal film 74 and the second metal film 72 are aligned to overlap, and when laser light is shone on the subcarrier 20, or directly through the subcarrier, they are heated and the first metal film 74 and the second metal film 72 melt. When the first metal film 74 and the second metal film 72 are in contact with each other and heated by laser light, the components of the second metal film 72 eutectic and diffuse into the first metal film 74.

[0056] The second metal film 72, which is placed at the substrate-side bonding portions 42-1, 42-2, and 42-3, is preferably made of Sn or an alloy containing Sn such as Sn-Ag-Cu. The first metal film 74, which is placed at the base-side bonding surfaces 22-1, 22-2, and 22-3, is preferably made of a metal that can eutectic with Sn, and may include, for example, one selected from the group consisting of Au, Si, Al, Ni, Pb, Zn, and Pt, or an alloy thereof. Note that the three-layer structure of the metal film M shown in Figures 2 and 3 may be in the reverse order. That is, the second metal film 72 may be placed on the base 20 side and the first metal film 74 may be provided on the optical waveguide substrate 40 side. These metal films are formed by sputtering, vapor deposition, or the like.

[0057] In the optical element assembly 10 according to this embodiment, since the alignment marker AM is provided on the outermost surface of the optical waveguide layer 50, extending inward from the outer edge, the element can be miniaturized without worrying about the influence of the alignment marker size on the emission surface. Furthermore, even when the element is miniaturized, the alignment marker AM can be easily detected by viewing the optical waveguide layer 50 in plan view, and the laser diode assembly 3 can be precisely aligned based on the coordinate components of the alignment marker AM.

[0058] In the above embodiment, the alignment marker AM is exemplified as a metal film provided on the optical waveguide layer 50. However, the present invention is not limited to the above example, and the alignment marker AM may be a metal film provided in a region where a part of the optical waveguide layer 50 has been removed, as shown in Figure 5(a). In such a configuration, after forming the optical waveguide layer 50, the region for forming the alignment marker AM can be removed by etching, and then the alignment marker AM can be formed by deposition, sputtering, CVD, etc. Also, as shown in Figure 5(b), the alignment marker AM may be a recess. Although the configuration in which the alignment marker AM is a recess is more difficult to detect than the configuration in which the alignment marker AM is a metal film, it is possible to detect the outline as a dark line by observation from above, and this embodiment can be implemented even with such a configuration.

[0059] [Manufacturing method for optical element assemblies] The following describes a method for manufacturing an optical element assembly according to one embodiment of the present invention, using the method for manufacturing the optical element assembly 100 according to the above embodiment as an example. The method for manufacturing an optical element assembly according to one embodiment of the present invention includes a bonding step of bonding a laser diode assembly to an optical waveguide chip 45 on which an optical waveguide layer 50 having an alignment marker AM is formed. The optical waveguide chip 45 is a chip-shaped component in which an optical waveguide layer 50 is laminated on an optical waveguide substrate 40. The alignment marker AM is provided on the outermost surface of the optical waveguide layer 50, inward from the outer edge. In the bonding step, the laser diode assembly is bonded to the optical waveguide chip 45 while aligning the optical waveguide layer 50 while observing it in a planar view.

[0060] The method for manufacturing an optical element assembly according to this embodiment includes, for example, an alignment marker formation step and a bonding step.

[0061] (Alignment marker formation process) In the alignment marker formation process, alignment markers AM are formed on the outermost surface of the optical waveguide layer 50, inward from the outer edge. The alignment marker formation process may be performed on the optical waveguide substrate in wafer form, on a bar-shaped optical waveguide substrate, or on a chip made from a bar-shaped component. In this embodiment, the case in which alignment markers AM are formed on an optical waveguide chip 45, which is a chipped component, will be described as an example.

[0062] Figure 6(a) is a plan view showing an example of the configuration of an optical waveguide chip that can be used in a method for manufacturing an optical element assembly according to one embodiment of the present invention, and Figure 6(b) is a view of the optical waveguide chip from the side. As shown in Figures 6(a) and 6(b), the optical waveguide chip 45 comprises an optical waveguide substrate 40 and an optical waveguide layer 50 formed on the optical waveguide substrate 40. An optical waveguide 51 is formed inside the optical waveguide layer 50. In the example shown in Figure 5, an alignment marker AM is provided on the outside in the width direction of the optical waveguide chip 45 relative to the optical waveguide 51, but the alignment marker AM may also be provided at a position overlapping with the optical waveguide 51, and may be provided between the entrance ports 51A-1 and 51A-2 in the width direction, or between the entrance ports 51A-2 and 51A-3.

[0063] The alignment marker AM formation process can be carried out by sputtering, CVD (chemical vapor deposition), vapor deposition, etc. Techniques such as photomasking, vapor deposition, sputtering, lift-off, and etching can be utilized to form the alignment marker AM in a predetermined shape.

[0064] (Joining process) Next, the optical waveguide layer 50 is aligned while being observed in a plan view, and the laser diode assembly 3 is joined to the optical waveguide chip 45. In the manufacturing method of the optical element assembly according to this embodiment, alignment is performed using two optical systems: an optical system for detecting laser output and an optical system for reading markers. This is because the coordinates of the alignment marker AM can be identified with sufficient accuracy within this range.

[0065] Figures 7 and 8 are schematic diagrams illustrating the configuration of a manufacturing method for an optical element assembly according to one embodiment of the present invention, showing the bonding process. Alignment is performed based on the coordinates of the alignment marker AM identified by observing the optical waveguide layer 50 in a plan view, and the relative coordinates, which are the relative positional relationship between the entrance ports 51A-1 to 51A-3 and the alignment marker AM, which are known in advance. Therefore, first, the coordinates of the alignment marker AM are read by an optical system for marker reading. Next, the coordinates of the entrance ports 51A-1 to 51A-3 are determined based on the coordinates of the alignment marker AM.

[0066] Next, the laser diode assembly 3 is aligned so that the coordinates and the active layer 35 face each other, more specifically, so that the widthwise centers C30-1 to C30-3 and the entrance ports 51A-1 to 51A-3 face each other. With the alignment complete, the substrate-side joints 42-1 to 42-3 of the optical waveguide substrate 40 and the base-side joint surfaces 22-1 to 22-3 of the laser diode assembly 3 are brought into contact.

[0067] With the laser diode assembly 3 aligned, laser light is shone from the laser 90 onto the subcarrier 20, and the first metal film 74, the second metal film 72, and the third metal film (eutectic film) 73 are softened or melted by heat transfer from the subcarrier 20. As described above, after the alignment is performed, the laser light may be shone on the laser diode assembly 3 and the optical waveguide substrate 40 while they are fixed in place to prevent movement, thereby bonding them together. Alternatively, the laser diode assembly 3 and the optical waveguide substrate 40 may be fine-tuned while the laser light is shone on to achieve precise alignment. To achieve precise alignment, a preliminary adjustment process may be performed before shone the laser light from the laser 90, or while fine-tuning during shone, in which each laser diode 30-1 to 30-3 is made to emit light, the output of the laser light passing through the cores 51-1 to 51-3 and out of the output port 64 is identified by an optical system for laser output detection, and the intensity of each color component is checked while fine-tuning is performed. The optical system for detecting laser output is, for example, arranged perpendicular to the surface of the emission surface 50B so as to face the emission port 64.

[0068] As the laser 90, any known laser capable of heating the first metal film 74 and the second metal film 72 to a temperature at which they eutectic can be used, but it is preferable to use a laser capable of emitting laser light with a wavelength of 1064 nm or longer, such as a YAG laser. When irradiating with a short-wavelength laser light during the bonding process, the metal film M is indirectly heated via the base 20.

[0069] In the manufacturing method of the optical element assembly according to this embodiment, by providing the alignment marker AM on the outermost surface of the optical waveguide layer 50, it is possible to miniaturize the optical element assembly and achieve high-precision alignment.

[0070] Some optical devices have extremely thin optical waveguide layers, sometimes only a few micrometers thick. Therefore, as described below, forming alignment markers on the incident or exit surface of the optical waveguide layer and performing alignment by observation with a side-view optical system is difficult to achieve in terms of miniaturization. For example, removing a portion of the optical waveguide layer to create a blank region or embedding a thin metal film may be difficult due to the thickness of the optical waveguide layer. Furthermore, even with sufficient thickness, the thickness of a metal film detectable by side-view optical system observation is typically 10 micrometers or more, and depositing such a thick metal film can be difficult. Especially when metal film deposition must be done using a dry process, depositing a metal film of detectable thickness is not practical. Additionally, plating processes may be necessary to facilitate optical detection, or damage may occur after deposition, making it difficult to maintain the desired shape. Insufficient shape maintenance affects the accuracy of alignment.

[0071] In contrast, according to this embodiment, even when it is difficult to form an identifiable alignment marker on the incident or exit surface due to the thickness of the optical waveguide layer, an alignment marker AM of sufficient size can be easily formed without hindering the miniaturization of the element by forming it on the outermost surface of the optical waveguide layer and observing it from a direction perpendicular to the surface of the optical waveguide layer 50.

[0072] Figures 9(a) and 9(b) show modified examples of the manufacturing method for an optical element assembly according to one embodiment of the present invention. The timing of forming the alignment marker AM is not limited to after the optical waveguide substrate has been chipped, as in the above configuration, but may be performed before chipping. Here, the optical waveguide chip 45 is obtained by dicing (dicing) through a process of forming an optical waveguide layer having a plurality of optical waveguides on a wafer (optical waveguide layer formation process), cutting out a plurality of optical waveguide bar members B having an optical waveguide layer from the wafer (bar member cutting process), and depositing a plurality of second metal films 72 (first metal film deposition process). As shown in Figure 9(a), the alignment marker AM may be formed by performing the alignment marker formation process after the bar member cutting process and before the dicing process. Also, as shown in Figure 9(b), the alignment marker formation process may be performed after the dicing process. Thus, the alignment marker formation process can be performed at any stage before the bonding process. Furthermore, if the alignment marker formation process is performed before the dicing process, the bonding process may be performed before the dicing process. That is, multiple diode assemblies may be bonded to a bar member, which is made up of multiple optical waveguides that will later become part of separate optical waveguide chips 45, and then diced. This manufacturing method can reduce the number of steps required to produce the elements that will become multiple optical element assemblies. Also, in this case, if at least one alignment marker AM is provided on one bar member B, the relative coordinates of all the entrances on the bar member B with respect to the alignment marker AM can be determined, so it is not necessary to form alignment markers in all regions that will become separate chips. Alternatively, alignment marker AM may be formed in regions that will become separate chips at the wafer stage before the bar member cutting process and after the optical waveguide layer formation process.

[0073] [Optical Module] Figure 10 is a schematic plan view of the optical module of this embodiment. Figure 11 is a schematic cross-sectional view of the optical module shown in Figure 10, cut in the XZ plane. The optical module 1000 shown in Figure 10 houses the optical element assembly according to the above embodiment within a package 110. The optical element assembly shown in Figure 10 is also referred to as a laser assembly.

[0074] The package 110 may contain known components other than the optical element assembly according to the above embodiment. For example, a photodetector (PD) can be housed within it. By incorporating a photodiode (PD), it is possible to check fluctuations in the optical output of the laser diode by observing the current flowing through the PD. Furthermore, by monitoring the current flowing through the PD, the drive current of the laser diode can be controlled to keep the output constant.

[0075] Package 110 comprises a main body 102 having a cavity structure and a cover 105 that covers the main body 102. The main body 102 has a bottom portion on which the components to be housed inside are placed, and wall portions (side wall portions) 102a arranged to surround those components from the sides. A light-transmitting window 101 is formed in the wall portion (side wall portion) 102a, which is positioned in the direction from which the laser light is emitted, allowing the laser light L emitted from the laser diode 30 to pass through optically.

[0076] A light-transmitting window (aperture) 101 is formed in the side wall portion 102a of the housing portion 107, near the laser beam L emitted from the optical module 1000. The aperture 101 is formed approximately at the point where it intersects with the optical axis of the laser beam emitted from the side wall portion 102a. The aperture 101 is completely covered from the outside of the side wall portion 102a by a glass plate 220. In other words, the housing portion 107 is hermetically sealed by the glass plate 220 in addition to the cover 105. Although a glass plate 220 is used for hermetically sealing, it is not limited to a glass plate as long as it is a material that can transmit laser light. Anti-reflective coatings (not shown) may be provided on both surfaces of the glass plate 220.

[0077] The electrode section 108 is positioned towards the front of the housing section 107 in the x-direction, i.e., towards the rear in the x-direction. The upper surface of the electrode section 108 is located below the upper surface of the housing section 107. The bottom surface of the electrode section 108 is located at approximately the same height as the bottom surface of the housing section 107. Multiple external electrode pads 210 are provided on the upper surface of the electrode section 108 at intervals in the y-direction.

[0078] As shown in Figure 10, a base 180 is provided at a predetermined position at the bottom of the housing section 107 for installing an optical module including a laser diode 30, a subcarrier 20 on which it is mounted, and a PLC 50 and an optical waveguide substrate 40 on which it is formed. This optical module is mounted on the base 180. In other words, this optical module is located in the internal space of the housing section 107. This optical module is formed such that the bottom surface (base bottom surface) 20b of the subcarrier (base) 20 and the bottom surface (substrate bottom surface) 43 of the optical waveguide substrate 40 are located on substantially the same plane S. Therefore, in this optical module, both the subcarrier 20 and the optical waveguide substrate 40 are joined to the upper surface 180a (one inner surface) of the base 180.

[0079] The bottom surface (base bottom surface) 20b of the subcarrier 20 and the bottom surface (substrate bottom surface) 43 of the optical waveguide substrate 40 should be joined to the top surface 180a (one inner surface) of the base 180 via an adhesive layer 182. This adhesive layer 182 uses a material in which a filler is mixed with resin to enhance thermal conductivity. Examples of resins that make up the adhesive layer 182 include epoxy resin. In addition, copper powder, aluminum powder, alumina powder, etc., can be used as fillers to improve the thermal conductivity of the resin. Furthermore, in order to maintain a certain level of thermal conductivity, the thermal conductivity of the adhesive layer 182 is preferably 0.5 W / m·K or higher, preferably 1 W / m·K or higher, and even more preferably 4 W / m·K or higher.

[0080] In this way, by joining both the subcarrier 20 of the optical module and the optical waveguide substrate 40 to the upper surface 180a of the base 180 of the package 110, the heat generated by the operation of the laser diode 30 can be efficiently dissipated toward the base 180 from both the bottom surface (base bottom surface) 20b of the subcarrier 20 and the bottom surface (substrate bottom surface) 43 of the optical waveguide substrate 40. Furthermore, by joining both the bottom surface 20b of the subcarrier 20 and the bottom surface 43 of the optical waveguide substrate 40 using an adhesive layer made of resin mixed with filler, heat can be efficiently propagated toward the base 180 from both the bottom surface 20b of the subcarrier 20 and the bottom surface 43 of the optical waveguide substrate 40.

[0081] Figure 12 is a conceptual diagram of an optical module equipped with an optical waveguide layer having an optical waveguide, and shows a plan view illustrating the internal configuration of the package in the optical module of Figure 10. Figure 13 is a schematic plan view of the optical module shown in Figure 12 as seen from the exit surface. Components common to the optical element assembly described above may be given the same reference numerals and their descriptions may be omitted. Figure 12 shows an example in which the optical element assembly has a near-infrared laser diode in addition to an RGB laser diode. Since near-infrared lasers are invisible, they can be used for eye tracking.

[0082] In the optical module 2000 shown in Figure 12, an optical element assembly 100B is housed in a package 110, comprising an RGB laser diode 30 and a base 20 on which the RGB laser diode 30 is mounted, a near-infrared laser diode 30-4 and a base 20-4 on which the near-infrared laser diode 30-4 is mounted, an optical waveguide substrate 140 on which PLC 150 is formed on the main surface, and metal films 72, 73, and 74 that join the base 20 and base 20-4 to the optical waveguide substrate 140.

[0083] The near-infrared laser diode 30-4 is mounted on the subcarrier 20-4, similar to the laser diode 30, and the PLC 150 is formed on the optical waveguide substrate 140.

[0084] The optical module 2000 includes a PLC 150 within the package 110, which includes optical waveguides 151 (151-1, 151-2, 151-3) for guiding the laser light emitted from the laser diode 30, and an optical waveguide 152 for guiding the near-infrared laser light emitted from the near-infrared laser diode 30-4. In the optical module 2000, the optical waveguide substrate 140 on which the PLC 150 is formed, the subcarrier 20 on which the laser diode 30 is mounted, and the subcarrier 20-4 on which the near-infrared laser diode 30-4 is mounted are metal-bonded and integrated. This metal joint allows for precise optical axis alignment and enables miniaturization.

[0085] Examples of optical waveguide substrates 140 include sapphire substrates, Si substrates, and thermally oxidized silicon substrates.

[0086] In the optical module 200, the PLC 150 includes an optical waveguide film 150A having optical waveguides 151 and 152, and a waveguide cladding film 150B formed on the optical waveguide film 150A so as to cover the optical waveguides 151 and 152. The waveguide cladding film 150B has a lower refractive index than the optical waveguide film 150A. The optical waveguide film 150A corresponds to the core described above, and the waveguide cladding film 150B corresponds to the cladding described above.

[0087] When the optical waveguide film 150A is constructed from a lithium niobate film, for example, a c-axis oriented lithium niobate film can be used. 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 by the underlying substrate. An epitaxial film is a film that has a single crystal orientation in the z direction and in the xy plane, and in which the crystals are aligned in the x, y, and z axis directions. Whether the film formed on the optical waveguide substrate 140 is an epitaxial film can be proven, for example, by checking the peak intensity and poles at the orientation position in 2θ-θ X-ray diffraction.

[0088] The thickness of the optical waveguide film 150A is, for example, 2 μm or less. The thickness of the lithium niobate film refers to the thickness of the portion other than the ridge. If the lithium niobate film is too thick, there is a risk of reduced crystallinity. Furthermore, the thickness of the optical waveguide film 150A is, for example, about 1 / 10 or more of the wavelength of the light used. If the thickness of the optical waveguide film 150A is too thin, the confinement of light will be weak, and light will leak into the optical waveguide substrate 140 and the waveguide cladding film 150B.

[0089] Optical waveguides 151 and 152 are paths through which light propagates. Optical waveguides 151 and 152 are ridges protruding from the first surface 150AA of the slab layer 150Aa of the optical waveguide film 150A. Hereinafter, optical waveguides 151-1, 151-2, 151-3, and 152 may be referred to as ridges 151-1, 151-2, 151-3, and 152, respectively. The first surface 150AA is the upper surface of the part of the optical waveguide film 150A other than the ridges (slab layer 150Aa). The optical waveguide film 150A consists of ridges 151-1, 151-2, 151-3, and 152 and the slab layer 150Aa.

[0090] The cross-sectional shapes of ridges 151-4 and 152 shown in Figure 11 are rectangular, but any shape that can guide light is acceptable, such as a trapezoid, triangle, or semicircle. 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 (protrusion height Ha from the first surface 150AA) is preferably, for example, 0.1 μm or more and 1.0 μm or less.

[0091] As shown in Figure 12, optical waveguides 151-1, 151-2, and 151-3 are joined together just before reaching the output surface of the PLC 150. That is, optical waveguides 151-1, 151-2, and 151-3 merge sequentially as they move forward in the x-direction, converging into a single optical waveguide 151-4. To prevent light leakage from optical waveguides 151-1, 151-2, and 151-3, it is preferable that optical waveguides 151-1, 151-2, and 151-3 are each connected to optical waveguide 151-4 with a radius of curvature greater than or equal to a predetermined radius of curvature.

[0092] Through a metal junction between the optical waveguide substrate 140 and the subcarrier 20, the optical axes of the PLC50 are precisely aligned so that the center of the entrance of each ridge 151-1, 151-2, 151-3, and 152 of the PLC50 and the optical axis of the light emitted from the corresponding laser diodes 30-1, 30-2, 30-3, and 30-4 are nearly aligned and optically connected. Each ridge and its corresponding laser diode are positioned opposite each other.

[0093] The entrance ports of each optical waveguide 151-1, 151-2, 151-3, and 152 face the exit ports of each laser diode 30-1, 30-2, 30-3, and 30-4, and the light emitted from the exit ports of each laser diode 30-1, 30-2, 30-3, and 30-4 is positioned to enter each entrance port, so that each laser diode 30-1, 30-2, 30-3, and 30-4 is optically connected to each optical waveguide 151-1, 151-2, 151-3, and 152.

[0094] As shown in Figure 12, the red, green, and blue light emitted from the laser diodes 30-1, 30-2, and 30-3 are incident on the respective entry points of the optical waveguides (ridges) 151-1, 151-2, and 151-3, and then propagate through each ridge. The red and green light propagating through ridges 151-3 and 151-2 are combined at a predetermined confluence point 157-1 located behind confluence point 157-2 in the x-direction. The combined red and green light and the blue light propagating through 151-2 are combined at confluence point 57-2. The RGB light combined at confluence point 57-2 propagates through ridge 151-4, reaches the exit surface, and is emitted from the exit surface. Furthermore, the near-infrared light emitted from the near-infrared laser diode 30-4 propagates along the ridge 152, reaches the emission surface, and is emitted from the emission surface.

[0095] Each of the optical waveguides 151-1, 151-2, 151-3, and 152 in the PLC150 may be a Mach-Zehnder type optical waveguide.

[0096] [XR Glasses] The XR glasses according to this embodiment have the optical module according to the above embodiment mounted on the glasses. XR glasses are glasses-type devices, and XR is a general term for virtual reality (VR), augmented reality (AR), and mixed reality.

[0097] Figure 14 shows a conceptual diagram illustrating the XR glasses according to this embodiment. The XR glasses 10000 shown in Figure 14 have an optical module 1001 mounted on a frame 10010. The symbol L represents the image display light.

[0098] In Figure 14, the optical module 1001, the optical scanning mirror 3001, and the optical system 2001 connecting the optical module 1001 and the optical scanning mirror 3001 are collectively referred to as the optical engine 5001 in this specification. The optical module 1001 can be any of the optical modules according to the above embodiment. The optical engine is also referred to as the optical engine module.

[0099] For example, the light source in the optical module 1001 can be one that includes RGB laser diodes, such as a red laser diode 30-1, a green laser diode 30-2, and a blue laser diode 30-3, and a near-infrared laser diode 30-4.

[0100] For example, the light source in the optical module 1001 can be one that includes RGB laser diodes, such as a red laser diode 30-1, a green laser diode 30-2, and a blue laser diode 30-3, and a near-infrared laser diode 30-4.

[0101] Figure 15 is a conceptual diagram showing how an image is projected directly onto the retina by laser light emitted from an optical module such as XR glasses shown in Figure 14. As shown in Figure 15, the laser light emitted from the optical module 1001 attached to the eyeglass frame is reflected by the optical scanning mirror 3001, and the reflected light is reflected by a mirror 4001 that reflects towards the human eyeball E, enters the human eyeball E, and can project an image (video) directly onto the retina M. By incorporating an eye-tracking mechanism, images are projected directly onto the retina while eye tracking is performed. A known eye-tracking mechanism can be used.

[0102] The optical scanning mirror 3001 is, for example, a MEMS mirror. To project a 2D image, it is preferable to use a two-axis MEMS mirror that vibrates to reflect laser light by changing the angle in the horizontal (X direction) and vertical (Y direction).

[0103] The optical system 2001 for optically processing the laser light emitted from the optical module 1001 includes a collimator lens 2001a, a slit 2001b, and an ND filter 2001c. This optical system is an example, and other configurations are also possible.

[0104] The optical engine 5001 includes a laser driver 1100, an optical scanning mirror driver 1200, and a video controller 1300 that controls these drivers.

[0105] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various omissions, substitutions, modifications, and changes are possible within the scope of the gist of the present invention as described in the claims. These embodiments and their variations are included in the scope and gist of the invention, as well as in the scope of the invention and its equivalents as described in the claims. [Explanation of symbols]

[0106] 3,3-1,3-2,3-3 Laser Diode Assembly 10 Optical element assembly 20, 20-1, 20-2, 20-3, 20-4 Base (subcarrier) 20b Bottom (base bottom) 21-1, 21-2, 21-3 Main surface 22,22-1, 22-2, 22-3 Base side joint surface (joint surface) 30, 30-1, 30-2, 30-3 Laser Diodes 30 Laser Diodes 30 RGB laser diodes 30-1 Red laser diode 30-2 Green laser diode 30-3 Blue laser diode 31, 31-1, 31-2, 31-3 Exit surface 35 Active layer 30-4 Near-infrared laser diode 40 Optical waveguide substrate 41 Top side 42 Joint surface 42, 42-1, 42-2, 42-3 Substrate-side bonding area 43 Bottom (bottom of board) 45 Optical waveguide chips 50 Optical waveguide layer 50A entrance surface 50B Output surface 50C, 50D side 51 Optical waveguide 51-1, 51-2, 51-3 Optical waveguide (core) 51A-1,51A-2,51A-3 Inlet 52 Clad 57-1,57-2 Merging position 64 Outlet 72,72-1, 72-2, 72-3 Second metal film 72, 73 and 74 Metal film 73 Third metal film (eutectic film) 74,74-1, 74-2, 74-3 First metal film 75 1st metal layer 76 Second metal layer 90 Lasers 100,100B Optical Element Assembly 101 Light-transmitting window (opening) 101 Aperture 102 Main Unit 102a Wall part (side wall part) 105 Cover 107 Storage Unit 108 Electrode section 110 packages 140 Optical waveguide substrate 151,151-1, 151-2, 151-3 Optical waveguide 151-1, 151-2, 151-3 Optical waveguides (ridges) 152 Optical waveguide (ridge) 157-1,157-2 Merging position 180 base 180a top 182 Adhesive layer 210 External electrode pads 220 glass plate 1000,1001 Optical Modules 1100 Laser Driver 1200 Optical Scanning Mirror Driver 1300 Video Controller 2000 Optical Module 2001 Optical system 2001a Collimator lens 2001b Slit 2001c ND filter 3001 Optical scanning mirror 4001 Mirror 5001 Optical Engine 10000 XR Glasses 10010 Frame B. Bar member for optical waveguide (bar member) C30-1,C30-2,C30-3 Width center L laser light

Claims

1. Laser diode and The system comprises an optical waveguide layer having an optical waveguide for guiding the laser light emitted from the laser diode, The optical waveguide layer has alignment markers, The alignment marker is provided on the outermost surface of the optical waveguide layer and is located inward from the outer edge of the optical waveguide layer, in an optical element assembly.

2. The optical element assembly according to claim 1, wherein the alignment marker is a metal film.

3. The optical element assembly according to claim 2, wherein the metal film is an Au film or a Ta film.

4. The optical element assembly according to claim 1, wherein the alignment marker is a recess.

5. A base on which the laser diode is mounted on the main surface, An optical waveguide substrate having the optical waveguide layer provided on its main surface, The optical element assembly according to claim 1, further comprising a plurality of metal films that join the base and the optical waveguide substrate.

6. The laser diodes are provided in multiple locations, The aforementioned base is composed of multiple bases, The optical element assembly according to claim 5, wherein the laser diode is mounted on each of the plurality of bases.

7. The optical waveguide substrate is a Si substrate, The core of the optical waveguide layer is SiO ２ The optical element assembly according to claim 5.

8. The optical waveguide substrate is SiO ２ It is a circuit board, The optical element assembly according to claim 5, wherein the core of the optical waveguide layer is SiN.

9. The optical waveguide substrate is a sapphire substrate, The core of the optical waveguide layer is LiNbO ３ The optical element assembly according to claim 5.

10. An optical module comprising an optical element assembly according to any one of claims 1 to 9 housed in a package.

11. The light source module according to claim 10, An optical engine comprising: a light scanning mirror that reflects light emitted from the aforementioned light source module at a different angle to display an image.

12. XR glasses equipped with the optical engine described in claim 11.

13. The process includes a bonding step of bonding a laser diode assembly to an optical waveguide substrate on which an optical waveguide layer having alignment markers is formed. The alignment marker is provided on the outermost surface of the optical waveguide layer, in a position inward from the outer edge. A method for manufacturing an optical element assembly, comprising the following steps: in the bonding step, aligning the optical waveguide layer while observing it in a planar view, and bonding the laser diode assembly to the optical waveguide chip.

14. The process further includes a dicing step and an alignment marker formation step prior to the aforementioned joining step. In the dicing process, the optical waveguide substrate on which the optical waveguide layer is formed is diced to form an optical waveguide semiconductor chip. The method for manufacturing an optical element assembly according to claim 13, wherein in the alignment marker formation step, an alignment marker is formed on the optical waveguide semiconductor chip.

15. The process further comprises a bar cutting process and an alignment marker formation process before the aforementioned joining process, and a dicing process after the aforementioned joining process. In the bar cutting process, a bar member for optical waveguides is cut from the wafer of the optical waveguide substrate on which the optical waveguide layer is formed. In the alignment marker formation step, an alignment marker is formed on the optical wave guide bar member. The method for manufacturing an optical element assembly according to claim 13, wherein in the dicing step, the optical waveguide bar member to which a plurality of laser diode assemblies are joined is diced.

16. A method for manufacturing an optical element assembly according to claim 14 or 15, wherein in the alignment marker formation step, a thin film of gold or tantalum is formed on the optical waveguide layer.

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