Optical module and method for manufacturing an optical module

Abstract

To provide an optical module that suppresses an increase in coupling loss.SOLUTION: An optical module is provided, comprising an optical component, a substrate with a principal surface for mounting the optical component, a mount provided on the principal surface of the substrate and configured to have the optical component mounted thereon, and at least one measurement reference part provided on the principal surface of the substrate at a distance from the mount and provided with a reference point to be used as a height reference when measuring the mounting height of the optical component.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to an optical module and a method for manufacturing an optical module. [Background Art]

[0002] Patent Document 1 discloses an optical component including a substrate on which a photoelectric conversion element is mounted, and a lens component disposed on the substrate. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2019-82508 [Summary of the Invention] [Problems to be Solved by the Invention]

[0004] In the optical module described in Patent Document 1, an optical component such as a lens component is mounted on a substrate so as to cover the photoelectric conversion element. Since this optical component is optically connected to another optical module, it is necessary to adjust the height position and tilt thereof with high accuracy during mounting. In this case, the height position and tilt of the optical component are adjusted with reference to the upper surface portion of the substrate, and it is conceivable to use a mounting region (formed by, for example, gold plating) having a uniform thickness in the upper surface portion of the substrate as a reference point. However, when the mounting region is used as the reference point, the mounting region cannot be used as the reference point after the optical component is disposed on the substrate, which makes it difficult to adjust the height position and tilt of the optical component with high accuracy. As a result, the optical module has insufficient mounting accuracy of the optical component, and connection loss when connected to another optical module may increase.

[0005] An object of the present disclosure is to provide an optical module and a method for manufacturing an optical module that can suppress an increase in connection loss. [Means for Solving the Problems]

[0006] This disclosure relates, in one aspect, to an optical module comprising: an optical component; a substrate having a main surface on which the optical component is mounted; a mounting section provided on the main surface of the substrate and configured for mounting the optical component; and at least one measurement reference section provided on the main surface of the substrate at a position away from the mounting section, including a reference point that serves as a height reference when measuring the mounting height of the optical component. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an optical module that suppresses the increase in connection loss. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view showing an optical module according to one embodiment. [Figure 2] Figure 2 is an exploded perspective view of the optical module shown in Figure 1. [Figure 3] Figure 3 is a top view of the substrate on which the second lens module of the optical module is mounted, viewed from above. [Figure 4] Figure 4 is a top view of the substrate shown in Figure 3, viewed from above. [Figure 5] Figure 5 is a cross-sectional view of the substrate shown in Figure 4. [Figure 6] Figure 6 is a cross-sectional view showing the adjustment of the mounting height of the second lens module in the optical module. [Figure 7] Figure 7 is a top view showing modified examples of the groove on the substrate shown in Figure 4, where (a) shows an example where the groove is linear in shape, and (b) shows an example where the groove is rectangular in shape and surrounds the mounting area. [Modes for carrying out the invention]

[0009] [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and explained. [1] An optical module according to one embodiment of the present disclosure comprises an optical component, a substrate having a main surface on which the optical component is mounted, a mounting section provided on the main surface of the substrate and configured for mounting the optical component, and at least one measurement reference section provided on the main surface of the substrate at a position away from the mounting section and including a reference point that serves as a height reference when measuring the mounting height of the optical component.

[0010] In this optical module, a measurement reference section is provided on the main surface of the substrate, separate from the mounting section where optical components are mounted. This section includes a reference point that serves as a height reference for measuring the mounting height of the optical components. In this case, the height position of the optical components can be adjusted with high precision using the measurement reference section when placing the optical components on the substrate, resulting in an optical module with high mounting accuracy. As a result, this optical module can suppress the increase in connection loss when connecting optical components to other optical components.

[0011] [2] In the optical module described in [1] above, the mounting section has a mounting surface on which optical components are mounted, and the measurement reference section has a reference surface including a reference point, and the mounting surface and the reference surface may have a predetermined positional relationship in the thickness direction of the substrate. In this case, since the mounting surface and the reference surface have a predetermined positional relationship (e.g., height relationship), the mounting height of the optical components mounted on the mounting surface can be adjusted with high precision using the reference point included in the reference surface as a reference. As a result, this optical module can more reliably suppress the increase in connection loss.

[0012] [3] In the optical module described in [2] above, the mounting surface and the reference surface may be in a positional relationship such that they are at the same height in the thickness direction of the substrate. In this case, the mounting height of the optical components mounted on the mounting surface can be adjusted with high precision using a reference point included in the reference surface as a reference, without considering the difference in height between the mounting surface and the reference surface in the thickness direction of the substrate. As a result, this optical module can more reliably suppress the increase in connection loss. Hereinafter, "the mounting surface and the reference surface are at the same height" means that, when the thickness of the mounting part or measurement reference part is taken as 100%, the difference between the height of the mounting surface and the height of the reference surface in the thickness direction of the substrate is within 5%.

[0013] [4] In the optical module described in [2] or [3] above, the mounting section has a first metal foil layer formed on the main surface of the substrate and a first metal plating layer formed on the first metal foil layer, and the measurement reference section has a second metal foil layer formed on the main surface of the substrate and a second metal plating layer formed on the second metal foil layer, the surface of the first metal plating layer may include the mounting surface and the surface of the second metal plating layer may include the reference surface. In this case, the thickness of the mounting section and the thickness of the measurement reference section can be adjusted more reliably and accurately, and the mounting height of the optical components mounted on the mounting section can be adjusted with high precision using the measurement reference section as a reference. As a result, this optical module can more reliably suppress the increase in connection loss.

[0014] [5] In any of the optical modules described in [1] to [4] above, at least one measurement reference section may include a plurality of measurement reference sections, and the plurality of measurement reference sections may be arranged on the main surface of the substrate so as to surround the mounting section. In this case, since the plurality of measurement reference sections are provided so as to surround the mounting section, not only the height position of the optical component but also its inclination can be adjusted with high precision after the optical component is placed on the substrate, resulting in an optical module with higher mounting precision. As a result, this optical module can further suppress the increase in connection loss.

[0015] [6] In the optical module according to any one of [1] to [5] above, the optical module further comprises a solder resist layer formed on the main surface of the substrate to fill a space between the mounting portion and the measurement reference portion, wherein the solder resist layer may be provided with a groove separating the mounting portion and the measurement reference portion. In this case, when an optical component disposed on the mounting portion is fixed using an adhesive, excess adhesive flows into the groove, thereby preventing excess adhesive from reaching the measurement reference portion. Therefore, the mounting height of the optical component mounted on the mounting portion can be more reliably adjusted with high accuracy based on the measurement reference portion. Accordingly, according to this optical module, an increase in connection loss can be more reliably suppressed.

[0016] [7] In the optical module according to any one of [1] to [6] above, the measurement reference portion may have a circular shape when viewed from a direction perpendicular to the main surface of the substrate, and the groove may be formed to surround the measurement reference portion. In this case, when adjusting the mounting height of the optical component using a laser measuring device that emits circular laser light, the area of the measurement reference portion can be easily made close to the cross-sectional area of the laser light. Therefore, according to this optical module, the measurement reference portion can be easily reduced in size, which makes it possible to reduce the size of the entire module. Further, since the periphery of the measurement reference portion is surrounded by the groove, adhesive can be more reliably prevented from reaching the measurement reference portion. Therefore, according to this optical module, it is possible to reduce the size of the module while suppressing an increase in connection loss.

[0017] [8] In the optical module according to any one of [1] to [7] above, the optical component may have a plurality of light input / output units each having an optical axis extending in a first direction on a plane parallel to the main surface, and the plurality of light input / output units may be arranged along a second direction intersecting the first direction on a plane parallel to the main surface. In this case, the optical component and another optical component can be easily connected such that the optical axis of the present optical component aligns with the optical axis of the other optical component having an optical axis extending in the first direction. Therefore, according to this optical module, an increase in connection loss when the optical component is connected to another optical component can be easily suppressed.

[0018] [9] A method for manufacturing an optical module according to an embodiment of the present disclosure includes the steps of: preparing an optical component and a substrate; forming a mounting portion for mounting the optical component on a main surface of the substrate; forming at least one measurement reference portion including a reference point serving as a height reference when measuring the mounting height of the optical component at a position on the main surface of the substrate that is separated from the mounting portion; and arranging the optical component on the mounting portion and adjusting the height of the optical component with the height of the measurement reference portion as the height reference. In this case, the height of the optical component can be adjusted by providing the measurement reference portion provided separately from the mounting portion on which the optical component is mounted. Therefore, according to this method for manufacturing an optical module, when arranging the optical component on the substrate, the height position of the optical component can be adjusted with high accuracy, so that an optical module with high mounting accuracy can be obtained.

[0019]

[10] In the method for manufacturing an optical module according to [9] above, in the step of forming the mounting portion, a first metal foil layer is formed on the main surface of the substrate, and a first metal plating layer is formed on the first metal foil layer; in the step of forming the measurement reference portion, a second metal foil layer is formed on the main surface of the substrate, and a second metal plating layer is formed on the second metal foil layer; the first metal foil layer and the second metal foil layer may be formed in the same process, and the first metal plating layer and the second metal plating layer may be formed in the same process. In this case, the mounting portion and the measurement reference portion can be formed through the same process, and it is easier to more reliably adjust the heights of the mounting portion and the measurement reference portion to be the same. This makes it possible to more easily adjust the mounting height of the optical component mounted on the mounting portion.

[0020] [Details of Embodiments of the Present Disclosure] Specific examples of the optical module and the method for manufacturing the optical module according to the present disclosure will be described below with reference to the drawings. The present invention is not limited to these examples, is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims. In the description of the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted.

[0021] Figure 1 is a perspective view showing an optical module according to one embodiment. As shown in Figure 1, the optical module 1 comprises a cable 3 containing a plurality of optical fibers 2 (see Figure 2) and a connector module 4 attached to the end of the cable 3. The connector module 4 is a connector that extends along the longitudinal direction X (also referred to as the X direction) and has a front end 4a and a rear end 4b in the X direction. The rear end 4b is located on the opposite side of the front end 4a in the X direction. The connector module 4 has an electrical connector at the front end 4a, the cable 3 is connected to the rear end 4b, and the optical fibers 2 of the cable 3 are inserted into the connector module 4 from the rear end 4b. In the following description, the width direction of the connector module 4 is referred to as the Y direction, and the height direction of the connector module 4 is referred to as the Z direction. The Z direction is perpendicular to the X direction and the Y direction.

[0022] Figure 2 is an exploded perspective view of the optical module 1 shown in Figure 1. As shown in Figures 1 and 2, the optical module 1 includes a connector module 4 comprising a first lens module 5, a second lens module 6 (optical component), a substrate 7, a mating spring 8, a metal member 9, a plug 10, a metal housing 11, a resin housing 12, and a front cap 13.

[0023] The first lens module 5 is an optical component that holds multiple optical fibers 2 constituting the cable 3 and can be connected to the second lens module 6 along the X direction. The first lens module 5 is a resin member having a substantially rectangular parallelepiped shape. The first lens module 5 has a front end surface 5a perpendicular to the X direction and a pair of guide holes 5b. The first lens module 5 is configured such that the tips of each optical fiber 2 of the cable 3 inserted from the rear end surface (not shown) of the first lens module 5 are exposed from the front end surface 5a.

[0024] The guide holes 5b are positioning holes provided to sandwich the multiple optical fibers 2 exposed on the front end surface 5a, and extend within the first lens module 5 along the X direction. When connecting the first lens module 5 to the second lens module 6, the pair of guide pins 6c of the second lens module 6 are inserted into the pair of guide holes 5b, thereby positioning the first lens module 5 relative to the second lens module 6.

[0025] The second lens module 6 is an optical component configured to be optically coupled to each end of a plurality of optical fibers 2 of the cable 3 held by the first lens module 5. The second lens module 6 is mounted to the substrate 7, for example, by being fixed with an adhesive. The second lens module 6 has a plurality of optical input / output sections 6a (see also Figure 3), a mirror surface 6b, and a pair of guide pins 6c. Each of the plurality of optical input / output sections 6a has an optical axis extending in the X direction on a plane parallel to the main surface 7a of the substrate 7 (see also Figure 5). The plurality of optical input / output sections 6a are arranged along the Y direction, which is perpendicular to the X direction, on a plane parallel to the main surface 7a. Optical signals emitted from each of the plurality of optical fibers 2 are incident into the interior of the second lens module 6 from the corresponding optical input / output section 6a. If a light-emitting element (not shown) is provided on the substrate 7, the light signal emitted from the light-emitting element is emitted from a plurality of light input / output sections 6a via the mirror surface 6b and incident on the tip of the optical fiber 2 held in the first lens module 5.

[0026] The mirror surface 6b is a reflective surface that forms an angle of approximately 45 degrees with respect to the X and Z directions. The mirror surface 6b is an optical structure for reflecting light emitted from the optical fiber 2 held by the first lens module 5 at a 90-degree angle toward a photodetector (not shown) provided on the substrate 7. If a light-emitting element (not shown) is provided on the substrate 7, the mirror surface 6b reflects the optical signal propagating perpendicularly from the light-emitting element toward the optical fiber 2 at a 90-degree angle. A pair of guide pins 6c are inserted into a pair of guide holes 5b of the first lens module 5 to align the optical coupling between the first lens module 5 and the second lens module 6.

[0027] The substrate 7 is a dielectric substrate having a roughly rectangular flat plate shape, on which a metallic wiring pattern (not shown) is formed on the surface. The substrate 7 is held by a metal member 9. On the main surface 7a of the substrate 7 (see also Figure 5), a mounting section 20, a measurement reference section 30, a solder resist layer 40, and grooves 50 are provided, which will be described later.

[0028] The mating spring 8 is a component that maintains the connection between the first lens module 5 and the second lens module 6 when the first lens module 5 is connected to the second lens module 6. The mating spring 8 is configured to maintain the connection by sandwiching the rear end 5c of the first lens module 5 and the rear end 6d of the second lens module 6 and pressing them against each other.

[0029] The metal member 9 is connected to the cable 3 and is a member that holds the substrate 7. The metal member 9 has a flat plate portion 9a extending in a direction perpendicular to the X direction and a pair of support portions 9b extending in the X direction from the flat plate portion 9a. An opening is formed in the flat plate portion 9a, and the optical fiber 2 is inserted through this opening. Each of the pair of support portions 9b has a recess 9c formed in it. The metal member 9 holds the substrate 7 by fitting the rear end 7b of the substrate 7 into the recess 9c.

[0030] The plug 10 covers and protects a plurality of terminals (not shown) provided on the front end 7c of the circuit board 7, and is connected to a connector provided on another circuit board (not shown). The plug 10 is attached to the circuit board 7 by inserting the front end 7c of the circuit board 7 into the insertion opening on the rear end 4b side of the plug 10 in the X direction.

[0031] The metal housing 11 has an upper housing 11a and a lower housing 11b. The second lens module 6 and the substrate 7 are arranged and protected inside the metal housing 11, which is formed by the upper housing 11a and the lower housing 11b.

[0032] The front cap 13 fits into the opening on the front side of the resin housing 12, closing the opening. The front cap 13 has a through hole that corresponds to the plug 10. Therefore, by inserting the plug 10 through the through hole of the front cap 13, the front cap 13 can be fitted into the opening on the front side of the resin housing 12.

[0033] Next, the second lens module 6 and the substrate 7 in the optical module 1 will be described in detail with reference to Figures 3, 4, and 5. Figure 3 is a top view of the substrate 7 on which the second lens module 6 is mounted, viewed from above. Figure 4 is a top view of the substrate 7, viewed from above. Figure 5 is a cross-sectional view of the substrate 7. As shown in Figures 3 to 5, in the optical module 1, the second lens module 6 is mounted on the main surface 7a of the substrate 7. As shown in Figure 4, the main surface 7a of the substrate 7 is provided with a mounting section 20, a plurality of measurement reference sections 30, a solder resist layer 40, and a plurality of grooves 50.

[0034] The mounting section 20 is the part on which the second lens module 6 is mounted. As shown in Figures 4 and 5, the mounting section 20 is provided on the main surface 7a of the substrate 7 and has a rectangular shape when viewed from a direction perpendicular to the main surface 7a. The mounting section 20 has a first metal foil layer 21 formed on the main surface 7a of the substrate 7 and a first metal plating layer 22 formed on the first metal foil layer 21. The first metal foil layer 21 is formed from, for example, copper foil, and the first metal plating layer 22 is formed from, for example, gold plating. A light-receiving element or a light-emitting element (neither shown) is provided on the mounting surface 20a of the mounting section 20 (the surface of the first metal plating layer 22). The mounting surface 20a and the light-receiving element or light-emitting element are electrically connected by a gold wire (not shown), etc. That is, the light-receiving element or light-emitting element is electrically connected to the wiring pattern of the substrate 7 via the gold wire, the first metal plating layer 22, and the first metal foil layer 21. The mounted second lens module 6 is fixed to the mounting surface 20a with adhesive.

[0035] Each of the multiple measurement reference sections 30 is a reference section used when measuring the mounting height of the second lens module 6. As shown in Figures 4 and 5, each measurement reference section 30 is provided on the main surface 7a of the substrate 7 at a distance from the mounting section 20. The measurement reference section 30 may be located at a distance of at least 1 mm in a straight line from the mounting section 20. The multiple measurement reference sections 30 are provided at four locations on the main surface 7a, for example, so as to surround the mounting section 20. The measurement reference sections 30 are all formed to have a circular shape when viewed from a direction perpendicular to the main surface 7a, and for example, the diameter of the measurement reference section 30 is 100 μm or more and 1 mm or less.

[0036] As shown in Figure 5, the measurement reference section 30 has a second metal foil layer 31 formed on the main surface 7a of the substrate 7 and a second metal plating layer 32 formed on the second metal foil layer 31. The second metal foil layer 31 is formed from, for example, copper foil, and the second metal plating layer 32 is formed from, for example, gold plating. The reference surface 30a of the measurement reference section 30 (the surface of the second metal plating layer 32) includes a reference point that serves as a height reference when measuring the mounting height of the second lens module 6. The mounting height of the second lens module 6 can be measured and adjusted using the reference surface 30a by the manufacturing method described later.

[0037] As shown in Figure 4, the solder resist layer 40 is an insulating layer formed on the main surface 7a of the substrate 7 to fill the space between the mounting section 20 and the measurement reference section 30. The solder resist layer 40 protects the wiring pattern of the substrate 7 and can be formed from, for example, a photosensitive resin ink.

[0038] Each of the multiple grooves 50 is configured to prevent leaked adhesive used when fixing the second lens module 6 from reaching the nearby measurement reference section 30. Each groove 50 is formed in the solder resist layer 40 and separates the mounting section 20 from the measurement reference section 30. Each groove 50 is formed in four locations in the solder resist layer 40, for example, surrounding each of the four measurement reference sections 30. When viewed from a direction perpendicular to the main surface 7a, each groove 50 has a circular shape that is concentric with the corresponding measurement reference section 30. The grooves 50 do not have to be concentric with the measurement reference section 30. The depth of the grooves 50 in the thickness direction of the substrate 7 is the same as the thickness of the solder resist layer 40, as shown in Figure 5. The depth of the grooves 50 in the thickness direction of the substrate 7 may be shorter than the thickness of the solder resist layer 40. The width of the grooves 50 is not particularly limited as long as it can prevent leaked adhesive, but for example it may be 100 μm or more and 1 mm or less.

[0039] Here, the positional relationship between the mounting surface 20a of the mounting section 20 and the reference surface 30a of the measurement reference section 30 will be explained using Figures 4 and 5. The mounting surface 20a and the reference surface 30a are set to have a predetermined height relationship in the thickness direction (Z direction) of the substrate 7. In the example shown in Figure 5, for example, the mounting surface 20a and the reference surface 30a are at the same height. Here, "the mounting surface 20a and the reference surface 30a are at the same height" means that, when the thickness of the mounting section 20 or the measurement reference section 30 is set to 100%, the difference between the height of the mounting surface 20a and the height of the reference surface 30a in the thickness direction of the substrate 7 is within 5%. By setting such a positional relationship in advance, the mounting height of the second lens module 6 can be easily measured or adjusted in the manufacturing method described later. The mounting surface 20a and the reference surface 30a may have other predetermined positional relationships in the thickness direction of the substrate 7 (positional relationships in which the mounting surface 20a and the reference surface 30a are not at the same height). For example, if the thickness of the mounting section 20 or the measurement reference section 30 is set to 100%, the deviation of the height of the mounting surface 20a and the height of the reference surface 30a in the thickness direction of the substrate 7 may be within a range of 10%.

[0040] Next, the manufacturing method of the optical module 1 will be described. First, a second lens module 6 having a plurality of light input / output sections 6a, a mirror surface 6b, and a pair of guide pins 6c, and a substrate 7 having a substantially rectangular flat dielectric substrate on which a metallic wiring pattern is formed are prepared.

[0041] Next, a mounting section 20 for mounting the second lens module 6 is formed on the main surface 7a of the substrate 7 (see Figures 4 and 5). In the process of forming the mounting section 20, a first metal foil layer 21 is formed on the main surface 7a of the substrate 7, and a first metal plating layer 22 is formed on the formed first metal foil layer 21. The first metal foil layer 21 is formed from, for example, copper foil, and the first metal plating layer 22 is formed by electroless gold plating using gold on this copper foil. The first metal plating layer 22 is, for example, 1 μm to 10 μm thick and is thinner than the first metal foil layer 21. The mounting section 20 is formed to have a rectangular shape when viewed from a direction perpendicular to the main surface 7a.

[0042] Furthermore, at least one measurement reference section 30 is formed on the main surface 7a of the substrate 7, at a position away from the mounting section 20, including a reference point that serves as a height reference when measuring the mounting height of the second lens module 6. In the step of forming the measurement reference section 30 according to this embodiment, a second metal foil layer 31 is formed at the four corners of the main surface 7a so as to surround the mounting section 20, and a second metal plating layer 32 is formed on the four formed second metal foil layers 31. The second metal foil layer 31 is formed from, for example, copper foil, and the second metal plating layer 32 is formed by electroless gold plating using gold on this copper foil. The second metal plating layer 32 is, for example, 1 μm or more and 10 μm or less, and is thinner than the second metal foil layer 31. Each of the measurement reference sections 30 is formed to have a circular shape when viewed from a direction perpendicular to the main surface 7a.

[0043] The mounting section 20 and the measurement reference section 30 described above may be formed in separate processes, but preferably, the mounting section 20 and the measurement reference section 30 may be created in the same process. In this case, the first metal foil layer 21 and the second metal foil layer 31 may be formed in the same process, and the first metal plating layer 22 and the second metal plating layer 32 may be formed in the same process (plating). In this case, since the mounting section 20 and the measurement reference section 30 are formed through the same process, it is easier to reliably adjust the heights of the mounting section 20 and the measurement reference section 30 to be the same. Furthermore, in the formed mounting section 20 and measurement reference section 30, it is easy to ensure that the mounting surface 20a and the reference surface 30a have a positional relationship in which they are at the same height in the thickness direction of the substrate 7.

[0044] Next, once the mounting section 20 and the measurement reference section 30 are formed, a solder resist layer 40 is formed on the main surface 7a to fill the gap between the mounting section 20 and the measurement reference section 30. The solder resist layer 40 is formed, for example, by applying a photosensitive resin ink and exposing it to light.

[0045] Next, the solder resist layer 40 is etched to form grooves 50. For etching the solder resist layer 40, for example, a laser processing method may be used. Alternatively, the solder resist layer 40 may be formed in such a way that a predetermined area of ​​the main surface 7a of the substrate 7 is exposed during the process of forming the solder resist layer 40, thereby forming the grooves 50 at that predetermined area. The grooves 50 are formed at four locations in the solder resist layer 40 so as to surround each of the measurement reference sections 30 provided at the four corners. When viewed from a direction perpendicular to the main surface 7a, the grooves 50 are formed to have a circular shape that is concentric with the corresponding measurement reference section 30. The depth of the grooves 50 in the thickness direction of the substrate 7 matches the thickness of the solder resist layer 40. The depth of the grooves 50 in the thickness direction of the substrate 7 may be shorter than the thickness of the solder resist layer 40.

[0046] Next, the second lens module 6 is placed on the formed mounting section 20, and the height of the second lens module 6 is adjusted based on the height position of the measurement reference section 30. Here, the method for adjusting the mounting height of the second lens module 6 will be specifically explained using Figure 6. Figure 6 is a cross-sectional view of the optical module 1 when adjusting the mounting height of the second lens module 6.

[0047] First, the second lens module 6 is placed in a predetermined position on the mounting section 20. At this time, as shown in Figure 3, the measurement reference sections 30 are positioned at the four corners of the second lens module 6. After this placement, a curable adhesive is applied between the second lens module 6 and the substrate 7 and partially cured to temporarily fix the second lens module 6 to the substrate 7. Alternatively, the adhesive may be applied in advance between the second lens module 6 and the mounting section 20, and then partially cured after the positioning in the planar direction is completed.

[0048] Next, as shown in Figure 6, a distance measuring device K is prepared and placed above the measurement reference unit 30, and the distance T1 (also referred to as distance T1) between the distance measuring device K and the measurement reference unit 30 (reference surface 30a) is measured. The distance measuring device K is, for example, a laser measuring device that emits a circular laser beam. At this time, the distance measuring device K measures the distance T1 at each of the measurement reference units 30 provided at the four corners. The distance measuring device K may calculate the average value of the measured distance T1 and store the measurement data, or it may store the measurement data individually as the distance T1 corresponding to each measurement reference unit 30. The distance measuring device K may also store the height corresponding to this distance T1 as height zero.

[0049] Next, once the measurement of distance T1 is complete, the distance measuring device K is placed above the mounting unit 20, and the distance T2 (also referred to as distance T2) between the distance measuring device K and the upper surface 6e of the second lens module 6 is measured. When measuring this distance T2, the distance measuring device K measures the distance (distance T2) to each of the measurement points L (see Figure 3) provided at the four corners of the upper surface 6e of the second lens module 6. The distance measuring device K may calculate the average value of the measured distances T2 and store the measurement data, or it may store the measurement data individually as distance T2 corresponding to each measurement point L.

[0050] Next, the difference between distance T1 and distance T2 (T1-T2) is calculated. In this embodiment, the mounting surface 20a and the reference surface 30a have a predetermined positional relationship, such as being at the same height in the thickness direction of the substrate 7. Therefore, the difference between distance T1 and distance T2 (T1-T2) becomes the mounting height of the second lens module 6. If distance T1 is set to a height of zero, the measured distance T2 becomes the mounting height of the second lens module 6. Furthermore, if the mounting surface 20a and the reference surface 30a have other predetermined positional relationships in the thickness direction of the substrate 7, the mounting height of the second lens module 6 from the mounting section 20 can be measured by adding or subtracting the difference in height between the mounting surface 20a and the reference surface 30a in the thickness direction of the substrate 7 to the difference between distance T1 and distance T2 (T1-T2). As a result, the mounting height of the second lens module 6 from the mounting section 20 can be measured without measuring the distance between the distance measuring device K and the mounting section 20.

[0051] Furthermore, the distance measuring device K measures the distance T2 between itself and each of the multiple measurement reference units 30, and the inclination of the main surface 7a of the substrate 7 can be measured from the difference between the multiple measured distances T2. In addition, the distance measuring device K measures the distance T2 between itself and each of the four measurement points L (see Figure 3) at the corners of the upper surface 6e of the second lens module 6, and the inclination of the upper surface 6e of the second lens module 6 can be measured from the difference between the multiple measured distances T2. Alternatively, the distance measuring device K may calculate the height of the four corners of the second lens module 6 from the difference between the distance T2 to the measurement points L at the four corners of the second lens module 6 and the distance T1 to the (closest) measurement reference unit 30 corresponding to each measurement point L. The position and inclination of the second lens module 6 may then be adjusted so that these four corner heights match.

[0052] Next, once the mounting height and inclination of the second lens module 6 on the substrate 7 are adjusted to a predetermined range, the adhesive that was temporarily holding the second lens module 6 in place is further cured to fix the second lens module 6 to the substrate 7. This completes the mounting of the second lens module 6 onto the substrate 7.

[0053] Next, as shown in Figure 3, the first lens module 5, which holds the ends of the multiple optical fibers 2 constituting the cable 3, is connected to the second lens module 6 mounted on the substrate 7. Then, a mating spring 8 is fitted into the connected first lens module 5 and second lens module 6 to maintain the connection between the first lens module 5 and the second lens module 6.

[0054] Next, the substrate 7 is sandwiched between the upper part 11a and lower part 11b of the housing, along with the first lens module 5 and the second lens module 6, and the substrate 7 is placed inside the metal housing 11. After that, the metal housing 11 is placed inside the resin housing 12, and the front cap 13 is fitted into the opening of the resin housing 12. The optical module 1 is obtained by the above manufacturing method.

[0055] As described above, in the optical module 1 according to this embodiment, a measurement reference section 30 is provided on the main surface 7a of the substrate 7, separate from the mounting section 20 on which the second lens module 6 is mounted, and includes a reference point that serves as a height reference when measuring the mounting height of the second lens module 6. This allows the height position of the second lens module 6 to be adjusted with high precision using the measurement reference section 30 when mounting the second lens module 6 on the substrate 7, resulting in an optical module 1 with high mounting accuracy. Therefore, with the optical module 1, it is possible to suppress the increase in connection loss when the second lens module 6 is connected to the first lens module 5 (multiple optical fibers 2).

[0056] Furthermore, in the optical module 1, the mounting section 20 has a mounting surface 20a on which the second lens module 6 is mounted, and the measurement reference section 30 has a reference surface 30a that includes a reference point, and the mounting surface 20a and the reference surface 30a have a predetermined positional relationship in the thickness direction of the substrate 7. Since the mounting surface 20a and the reference surface 30a have a predetermined positional relationship (e.g., height relationship), the mounting height of the second lens module 6 mounted on the mounting surface 20a can be adjusted with high precision based on the reference point included in the reference surface 30a. As a result, the optical module 1 can more reliably suppress the increase in connection loss.

[0057] Furthermore, in the optical module 1, the mounting surface 20a and the reference surface 30a may have a positional relationship where they are at the same height in the thickness direction of the substrate 7. In this case, the mounting height of the second lens module 6 mounted on the mounting surface 20a can be adjusted with high precision based on a reference point included in the reference surface 30a, without considering the difference in height between the mounting surface 20a and the reference surface 30a in the thickness direction of the substrate 7. As a result, the optical module 1 can more reliably suppress the increase in connection loss.

[0058] Furthermore, in the optical module 1, the mounting section 20 has a first metal foil layer 21 formed on the main surface 7a of the substrate 7 and a first metal plating layer 22 formed on the first metal foil layer 21, and the measurement reference section 30 has a second metal foil layer 31 formed on the main surface 7a of the substrate 7 and a second metal plating layer 32 formed on the second metal foil layer 31, the surface of the first metal plating layer includes the mounting surface 20a and the surface of the second metal plating layer 32 includes the reference surface 30a. With this configuration, the thickness of the mounting section 20 and the thickness of the measurement reference section 30 can be adjusted more reliably and accurately, and the mounting height of the second lens module 6 mounted on the mounting section 20 can be adjusted with high precision based on the measurement reference section 30. As a result, the optical module 1 can more reliably suppress the increase in connection loss.

[0059] Furthermore, the optical module 1 includes a plurality of measurement reference sections 30, which are arranged on the main surface 7a of the substrate 7 so as to surround the mounting section 20. This allows for high-precision adjustment of not only the height position but also the tilt of the second lens module 6 after it has been placed on the substrate 7, resulting in an optical module 1 with higher mounting accuracy. Thus, the optical module 1 can further suppress the increase in connection loss.

[0060] Furthermore, the optical module 1 includes a solder resist layer 40 formed on the main surface 7a of the substrate 7, filling the space between the mounting section 20 and the measurement reference section 30. The solder resist layer 40 has a groove 50 that separates the mounting section 20 and the measurement reference section 30. As a result, when fixing the second lens module 6 placed on the mounting section 20 using adhesive, the adhesive preferentially flows into the groove 50, preventing the adhesive from reaching the measurement reference section 30. Therefore, the mounting height of the second lens module 6 mounted on the mounting section 20 can be adjusted more reliably and with higher precision using the measurement reference section 30 as a reference. Thus, the optical module 1 can more reliably suppress the increase in connection loss.

[0061] Furthermore, in the optical module 1, the measurement reference section 30 may have a circular shape when viewed from a direction perpendicular to the main surface 7a of the substrate 7, and the groove 50 may be formed to surround the measurement reference section 30. This makes it easier to bring the area of ​​the measurement reference section 30 closer to the cross-sectional area of ​​the laser beam when measuring distance using a laser measuring instrument that emits a circular laser beam. Therefore, with the optical module 1, it is easier to miniaturize the measurement reference section 30, and thus it is possible to miniaturize the entire module. In addition, since the area around the measurement reference section 30 is surrounded by the groove 50, it is possible to more reliably prevent adhesive from reaching the measurement reference section 30. Therefore, with the optical module 1, it is possible to miniaturize the module while suppressing an increase in connection loss.

[0062] Furthermore, in the optical module 1, the second lens module 6 has a plurality of optical input / output sections 6a, each having an optical axis extending in the X direction on a plane parallel to the main surface 7a, and the plurality of optical input / output sections 6a are arranged along the Y direction, which is perpendicular to the X direction, on a plane parallel to the main surface 7a. In this case, the first lens module 5 and the second lens module can be easily connected so that the optical axes between the optical fiber 2, which has an optical axis extending in the X direction, and the second lens module 6 coincide. Therefore, with the optical module 1, the increase in connection loss when the first lens module 5 and the second lens module are connected can be easily suppressed.

[0063] Furthermore, the manufacturing method of the optical module 1 according to this embodiment includes the steps of: preparing the second lens module 6 and the substrate 7; forming a mounting section 20 on the main surface 7a of the substrate 7 for mounting the second lens module 6; forming at least one measurement reference section 30 on the main surface 7a of the substrate 7, at a position away from the mounting section 20, which includes a reference point that serves as a height reference when measuring the mounting height of the second lens module 6; and mounting the second lens module 6 on the mounting section 20 and adjusting the height of the second lens module 6 using the height of the measurement reference section 30 as a height reference. This makes it possible to adjust the height of the second lens module 6 by providing a measurement reference section 30 that is separate from the mounting section 20 on which the second lens module 6 is mounted. Therefore, according to the manufacturing method of the optical module 1, the height position of the second lens module 6 can be adjusted with high precision after the second lens module 6 is placed on the substrate 7, and an optical module 1 with high mounting precision can be obtained.

[0064] Furthermore, in the manufacturing method of the optical module 1, in the step of forming the mounting section 20, a first metal foil layer 21 is formed on the main surface 7a of the substrate 7, and a first metal plating layer 22 is formed on the first metal foil layer 21. In the step of forming the measurement reference section 30, a second metal foil layer 31 is formed on the main surface 7a of the substrate 7, and a second metal plating layer 32 is formed on the second metal foil layer 31. The first metal foil layer 21 and the second metal foil layer 31 may be formed in the same process, and the first metal plating layer 22 and the second metal plating layer 32 may be formed in the same process. This makes it possible to form the mounting section 20 and the measurement reference section 30 through the same process, and makes it easier to adjust the heights of the mounting section 20 and the measurement reference section 30 to be identical more reliably. Thus, according to the manufacturing method of the optical module 1, it becomes possible to more easily adjust the mounting height of the second lens module 6 mounted on the mounting section 20.

[0065] [Differentiation] Here, a modified example of the groove 50 will be described using Figure 7. Figure 7 is a top view showing modified examples (groove 50A, groove 50B) of the groove 50 on the substrate 7 shown in Figure 4, where (a) shows an example where the groove is linear (groove 50A), and (b) shows an example where the groove is rectangular and surrounds the mounting area (groove 50B). In the following, we will mainly describe the differences from the groove 50 of the optical module 1 according to one embodiment, and other descriptions may be omitted.

[0066] As shown in part (a) of Figure 7, grooves 50A are formed in four locations on the solder resist layer 40, separating each of the four measurement reference sections 30 from the mounting section 20. When viewed from a direction perpendicular to the main surface 7a, all grooves 50A have a linear shape and extend inclined with respect to the width direction of the substrate 7. Groove 50B is formed in one location on the solder resist layer 40, separating the measurement reference section 30 from the mounting section 20, as shown in part (b) of Figure 7. When viewed from a direction perpendicular to the main surface 7a, groove 50B has a rectangular frame shape surrounding the mounting section 20. An optical module equipped with grooves 50A or groove 50B according to such a modified example can achieve the same effects as groove 50 of the optical module 1 described above. In addition, groove 50A can be miniaturized by shortening its length.

[0067] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments and can be applied to various embodiments. For example, although the shape of the groove 50 has been illustrated with examples, including modified examples, the groove 50 may have other shapes as long as it can separate the mounting portion 20 and the measurement reference portion 30. Also, although the measurement reference portion 30 has been illustrated as being made of metal, the measurement reference portion 30 may be made of other materials as long as its height position can be measured by a distance measuring device K such as a laser distance measuring device. Furthermore, although four measurement reference portions 30 were provided in the above embodiments, at least one measurement reference portion 30 is sufficient to adjust the mounting height of the second lens module 6, and the number of measurement reference portions 30 is not particularly limited. [Explanation of Symbols]

[0068] 1… Optical module 2… Fiber optic 3… Cable 4…Connector module 4a...front end 4b…Rear end 5…First lens module 5a...front end surface 5b... Guide hole 5c…rear end 6…Second lens module 6a...Light input / output section 6b... Mirror surface 6c… Guide pin 6d...rear end 6e…Top surface 7…Circuit board 7a…main surface 7b…Rear end 7c…front end 8…Matching spring 9…Metal components 9a...Flat plate part 9b...Support part 9c…recess 10...plug 11…Metal casing 11a... Top of the enclosure 11b...Bottom of the cabinet 12… Resin casing 13…Front cap 20…Implementation Section 20a…Implementation side 21...First metal foil layer 22…First metal plating layer 30...Measurement reference section 30a...Reference plane 31…Second metal foil layer 32…Second metal plating layer 40... Solder Resist Layer 50,50A,50B…Groove K…Distance measuring device L…Measurement point T1... Distance between distance measuring device K and measurement reference unit 30 T2…Distance between the distance measuring instrument K and the upper surface 6e of the second lens module 6

Claims

1. Optical components, A substrate having a main surface on which the optical components are mounted, A mounting section provided on the main surface of the substrate and configured to mount the optical components, The substrate includes at least one measurement reference section, which is provided on the main surface of the substrate at a location away from the mounting section and includes a reference point that serves as a height reference when measuring the mounting height of the optical component, Equipped with, The mounting portion has a mounting surface on which the optical component is mounted, The measurement reference section has a reference plane that includes the reference point, The mounting surface and the reference surface have a predetermined positional relationship in the thickness direction of the substrate. The mounting portion includes a first metal foil layer formed on the main surface of the substrate and a first metal plating layer formed on the first metal foil layer. The measurement reference section comprises a second metal foil layer formed on the main surface of the substrate and a second metal plating layer formed on the second metal foil layer. The surface of the first metal plating layer includes the mounting surface, The surface of the second metal plating layer includes the reference surface, and the optical module.

2. The mounting surface and the reference surface are in a positional relationship such that they are at the same height in the thickness direction of the substrate. The optical module according to claim 1.

3. The at least one measurement reference unit includes a plurality of measurement reference units, The plurality of measurement reference units are arranged on the main surface of the substrate so as to surround the mounting unit. The optical module according to claim 1 or claim 2.

4. The substrate further comprises a solder resist layer formed on the main surface of the substrate so as to fill the space between the mounting portion and the measurement reference portion. The solder resist layer has a groove formed between the mounting portion and the measurement reference portion. The optical module according to claim 1 or claim 2.

5. The measurement reference section, when viewed from a direction perpendicular to the main surface of the substrate, has a circular shape. The groove is formed so as to surround the measurement reference portion. The optical module according to claim 4.

6. The optical component has a plurality of light input / output portions, each having an optical axis extending in a first direction on a plane parallel to the main surface, and the plurality of light input / output portions are arranged along a second direction intersecting the first direction on the plane parallel to the main surface. The optical module according to claim 1 or claim 2.

7. The process of preparing optical components and substrates, A step of forming a mounting section for mounting the optical component on the main surface of the substrate, A step of forming at least one measurement reference portion on the main surface of the substrate at a position away from the mounting portion, which includes a reference point that serves as a height reference when measuring the mounting height of the optical component, A step of mounting the optical component on the mounting section and adjusting the height of the optical component using the height of the measurement reference section as the height reference, Equipped with, In the process of forming the mounting portion, a first metal foil layer is formed on the main surface of the substrate, and a first metal plating layer is formed on the first metal foil layer. A method for manufacturing an optical module, comprising the step of forming the measurement reference section, in which a second metal foil layer is formed on the main surface of the substrate and a second metal plating layer is formed on the second metal foil layer.

8. The first metal foil layer and the second metal foil layer are formed in the same process, The first metal plating layer and the second metal plating layer are formed in the same process. A method for manufacturing an optical module according to claim 7.

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