OPTICAL MODULE AND METHOD OF MANUFACTURING OPTICAL MODULE

An optical module includes a substrate including a main surface, an optical component including a bottom surface, and a first side surface and a second side surface each extending in a direction intersecting the bottom surface and facing each other, and an adhesion portion fixing the optical component to the substrate. The optical component is mounted on the substrate such that the bottom surface faces the main surface. In this optical module, the adhesion portion includes a plurality of first adhesion portions provided along the first side surface and a plurality of second adhesion portions provided along the second side surface.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority from Japanese Patent Application No. 2022-126513, filed on Aug. 8, 2022, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an optical module and a method of manufacturing an optical module.

BACKGROUND

JP2019-082508A discloses an optical module including a substrate to which photoelectric conversion elements are attached and a lens component disposed on the substrate.

SUMMARY

In one aspect, the present disclosure provides an optical module that includes a substrate including a main surface, an optical component including a bottom surface, and a first side surface and a second side surface each extending in a direction intersecting the bottom surface and facing each other, the optical component being mounted on the substrate such that the bottom surface faces the main surface, and an adhesion portion fixing the optical component to the substrate. In this optical module, the adhesion portion includes a plurality of first adhesion portions provided along the first side surface and a plurality of second adhesion portions provided along the second side surface

DETAILED DESCRIPTION

Problems to be Solved By the Present Disclosure

In the optical module described in JP2019-082508A, an optical component such as a lens component is mounted on a substrate with an adhesive or the like. In this case, one point along each side surface of the optical component is often fixed by an adhesive. Miniaturization is advanced in such an optical module, and it is becoming insufficient to fix the lens component on the substrate by the adhesive at one point for each side surface, and thus the optical component may be detached from the substrate when the optical module is connected to another optical module or the like.

Effects of the Present Disclosure

According to the present disclosure, an optical component is reliably fixed to a substrate in an optical module.

Description of Embodiments of Present Disclosure

First, the contents of embodiments of the present disclosure will be listed and explained.

[1] An optical module according to an embodiment of the present disclosure includes a substrate including a main surface, an optical component including a bottom surface, and a first side surface and a second side surface each extending in a direction intersecting the bottom surface and facing each other, the optical component being mounted on the substrate such that the bottom surface faces the main surface, and an adhesion portion fixing the optical component to the substrate. In this optical module, the adhesion portion includes a plurality of first adhesion portions provided along the first side surface and a plurality of second adhesion portions provided along the second side surface.

In this optical module of [1], the first adhesion portions are provided at a plurality of locations along the first side surface, and the second adhesion portions are provided at a plurality of locations along the second side surface. In this embodiment, the total area in which the optical component and the substrate are adhered to each other can be increased by the first adhesion portions and the second adhesion portions. According to this optical module, the optical component can be more firmly adhered to the substrate, and thus the optical component can be reliably fixed to the substrate. In addition, this optical module is provided with a plurality of first adhesion portions and a plurality of second adhesion portions, and thus a region where the optical component is adhered to the substrate is configured to be divided into a large number of regions. As a result, stress acting on the optical component during curing of the adhesion portion is dispersed. According to this optical module, deformation of the optical component can be suppressed.

[2] In the optical module according to [1] above, the plurality of first adhesion portions and the plurality of second adhesion portions may be disposed to be line-symmetric with respect to a center line. The center line passes through a center of the optical component in a direction in which the first side surface and the second side surface face each other and extends in a direction parallel to an optical axis of the optical component. In this embodiment, the optical component can be more stably fixed to the substrate by the first adhesion portions and the second adhesion portions. Therefore, the optical component can be more reliably fixed to the substrate in this optical module.

[3] In the optical module according to [1] or [2] above, the plurality of first adhesion portions may be provided between the main surface and at least one of a portion of the first side surface close to the bottom surface and a portion of the bottom surface close to the first side surface. The plurality of second adhesion portions may be provided between the main surface and at least one of a portion of the second side surface close to the bottom surface and a portion of the bottom surface close to the second side surface. In this embodiment, the adhesion portions are easily provided along the first side surface and the second side surface even in a state in which the optical component is disposed on the substrate and the position of the optical component is determined. Therefore, deformation of the optical component can be easily suppressed in this optical module while the adhesive force between the substrate and the optical component is easily improved.

[4] In the optical module according to any one of [1] to [3] above, the main surface of the substrate may be provided with a first uneven portion in at least a part of a portion where the main surface is in contact with the adhesion portion. In this embodiment, the adhesion portion flows into depressions of the first uneven portion, and an adhesion area where the adhesion portion and the substrate are in contact with each other can be increased. Therefore, the optical component can be more reliably fixed to the substrate in this optical module.

[5] In the optical module according to [4] above, an arithmetical mean roughness Ra of the first uneven portion may be equal to or greater than 0.4 μm and equal to or less than 0.7 μm. When the arithmetic mean roughness Ra of the first uneven portion is 0.4 μm or more, the adhesion portion easily flows into depressions of the first uneven portion, and the adhesion area in which the adhesion portion and the substrate are in contact with each other can be more reliably increased. In addition , when the arithmetic mean roughness Ra of the first uneven portion is 0.7 μm or less, it is possible to prevent the optical axis of the optical component from being deviated when the optical component is disposed on the main surface of the substrate. Therefore, it is possible to reliably fix the optical component to the substrate in this optical module while suppressing deviation of the optical axis or the like. The term “arithmetic mean roughness Ra” as used herein means a value measured in accordance with JIS B0601-2001.

[6] In the optical module according to any one of [1] to [5] above, the bottom surface of the optical component may be provided with a second uneven portion in at least a part of a portion where the bottom surface is in contact with the adhesion portion. In this embodiment, the adhesion portion flows into depressions of the second uneven portion, and an adhesion area where the adhesion portion and the optical component are in contact with each other can be increased. Therefore, the optical component can be more reliably fixed to the substrate in this optical module.

[7] In the optical module according to any one of [1] to [6] above, the first side surface and the second side surface of the optical component each may be provided with a third uneven portion in at least a part of a portion where the first side surface or the second side surface is in contact with the adhesion portion. In this embodiment, the adhesion portion flows into depressions of the third uneven portion, and an adhesion area where the adhesion portion and the optical component are in contact with each other can be increased. Therefore, the optical component can be more reliably fixed to the substrate in this optical module.

[8] In the optical module according to any one of [1] to [7] above, the first side surface and the second side surface may be inclined such that a distance between the first side surface and the second side surface decreases away from the bottom surface of the optical component. The adhesion portion may be provided on the inclined first side surface and the inclined second side surface. In this embodiment, it is possible to increase an adhesion area where the first adhesion portion and the first side surface are in contact with each other and an adhesion area where the second adhesion portion and the second side surface are in contact with each other. Therefore, the optical component can be more reliably fixed to the substrate in this optical module.

[9] A method of manufacturing an optical module according to an embodiment of the present disclosure includes preparing a substrate including a main surface, preparing an optical component including a bottom surface, and a first side surface and a second side surface each extending in a direction intersecting the bottom surface and facing each other, disposing the optical component on the main surface of the substrate such that the bottom surface faces the main surface, and fixing the optical component to the substrate by applying a first adhesive to a plurality of portions along the first side surface, by applying a second adhesive to a plurality of portions along the second side surface, and by curing the first adhesive and the second adhesive. According to this manufacturing method, it is possible to increase an adhesion area where the adhesive and the optical component are in contact with each other and an adhesion area where the adhesive and the substrate are in contact with each other. In addition, since the number of portions to which the adhesive is applied is increased, the stress acting on the optical component when the adhesive is cured is dispersed. Therefore, deformation of the optical component can be suppressed. As described above, according to the method of manufacturing an optical module, it is possible to manufacture an optical module in which deformation of an optical component is suppressed while the optical component is reliably fixed to the substrate.

[10] In the method of manufacturing an optical module according to [9] above, in the fixing, the first adhesive may be applied between the main surface and at least one of a portion of the first side surface close to the bottom surface and a portion of the bottom surface close to the first side surface, the second adhesive may be applied between the main surface and at least one of a portion of the second side surface close to the bottom surface and a portion of the bottom surface close to the second side surface, and the first adhesive and the second adhesive may be applied to be line-symmetric with respect to a center line. The center line passes through a center of the optical component in a direction in which the first side surface and the second side surface face each other and extends in a direction parallel to an optical axis of the optical component. In this embodiment, the optical component can be more stably fixed to the substrate by the first adhesive and the second adhesive. According to the method of manufacturing an optical module, the optical component can be more reliably fixed to the substrate.

Details of Embodiments of Present Disclosure

Specific examples of an optical module and a method of manufacturing an 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, but 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 redundant description is omitted.

FIG.1is a perspective view of an optical module according to one embodiment. As shown inFIG.1, an optical module1includes a cable3including a plurality of optical fibers2(seeFIG.2), and a connector module4attached to a tip of cable3. Connector module4is a connector extending along a longitudinal direction X (also referred to as an X direction), and has a front end4aand a rear end4bin the X direction. Rear end4bis located on the opposite side of front end4ain the X direction. Connector module4has an electrical connector at front end4a,cable3is connected to rear end4b,and optical fibers2of cable3are inserted into connector module4from rear end4b.In the following description, a width direction of connector module4is referred to as a Y direction, and a height direction of connector module4is referred to as a Z direction. The Z direction is orthogonal to the X direction and the Y direction.

FIG.2is an exploded perspective view of optical module1shown inFIG.1. As shown inFIGS.1and2, connector module4of optical module1includes a first lens module5, a fitting spring6, a metal member7, a plug8, a metal housing9, a resin housing10, a front cap11, a substrate20, and a second lens module30.

First lens module5is an optical component that holds a plurality of optical fibers2constituting cable3and is connectable to second lens module30along the X direction. First lens module5is a resin member having a substantially rectangular parallelepiped shape. First lens module5has a front end surface5aperpendicular to the X direction and a pair of guide holes5b.First lens module5is configured such that the tip of each optical fiber2of cable3inserted from the rear end surface (not shown) of first lens module5is exposed from front end surface5a.

Guide holes5bare holes for positioning provided so as to sandwich the plurality of optical fibers2exposed on front end surface5a,and each extends in first lens module5along the X direction. When first lens module5is connected to second lens module30, a pair of guide pins30cof second lens module30are inserted into the pair of guide holes5b,thereby positioning first lens module5with respect to second lens module30.

Fitting spring6is a member that maintains a connection state between first lens module5and second lens module30when first lens module5is connected to second lens module30. Fitting spring6is configured to hold a rear end5cof first lens module5and a rear end30dof second lens module30and press them against each other to maintain the connection state.

Metal member7is connected to cable3and holds substrate20. Metal member7includes a flat plate portion7aextending in a direction perpendicular to the X direction and a pair of support portions7bextending from flat plate portion7ain the X direction. An opening is formed in flat plate portion7a,and optical fibers2are inserted through the opening. A recess7cis formed in each of the pair of support portions7b.Metal member7holds substrate20by fitting a rear end20aof substrate20into recess7c.

Plug8covers and protects a plurality of terminals (not shown) provided on a front end20bof substrate20, and is connected to a connector provided on another substrate (not shown). Plug8includes an insertion port which is located between rear end4band front end4ain the X direction. Plug8is attached to substrate20by inserting front end of substrate20from the insertion port of plug8.

Metal housing9has a housing upper portion9aand a housing lower portion9b.Substrate20and second lens module30are disposed and protected inside metal housing9constituted by housing upper portion9aand housing lower portion9b.

Front cap11is fitted to the opening on the front side of resin housing10to close the opening. Front cap11has a through hole corresponding to plug8. Therefore, by inserting plug8into the through hole of front cap11, front cap11can be fitted to the opening on the front side of resin housing10.

Next, substrate20and second lens module30in optical module1will be described in detail with reference toFIGS.2,3,4and5A to5E.FIG.3is a top view of substrate20on which second lens module30of optical module1is loaded when viewed from above.FIG.4is a cross-sectional view showing a shape of a first uneven portion22of substrate20.FIGS.5A to5Eillustrate cross-sectional views each showing an example of a shape of a second uneven portion36of second lens module30, whereinFIG.5Ais a view showing an example of second uneven portion36having a rectangular shape,FIG.5Bis a view showing an example of a second uneven portion36A (modification of second uneven portion36) having a corrugated shape,FIG.5Cis a view showing an example of a second uneven portion36B (modification of second uneven portion36) having a trapezoidal shape,FIG.5Dis a view showing an example of a second uneven portion36C (modification of second uneven portion36) including holes each having a circular cross section, andFIG.5Eis a view showing an example of a second uneven portion36D (modification of second uneven portion36) including holes each having an inverted trapezoidal shape inverse to second uneven portion36B. As shown inFIG.3, second lens module30is mounted on substrate20by the plurality of adhesion portions40in optical module1.

As shown inFIG.3, substrate20is a member in which a metal wiring pattern (not shown) is formed on a surface of a dielectric substrate having a substantially rectangular flat plate shape. Substrate20is held by metal member7. Second lens module30is fixed on a main surface21of substrate20by the plurality of adhesion portions40which will be described later.

As shown inFIG.4, main surface21of substrate20may be provided with first uneven portion22that includes protrusions22aeach having a rectangular cross-section in at least a part of a portion where main surface21is in contact with adhesion portion40. The arithmetic mean roughness Ra of first uneven portion22is, for example, 0.4 μm or more. The arithmetic mean roughness Ra of first uneven portion22may be, for example, 0.7 μm or less. As a portion of adhesion portion40flows into depressions22bof first uneven portion22, the contact area between main surface21of substrate20and adhesion portion40increases. The cross-sectional shape of each protrusion22aof first uneven portion22is not limited to a rectangular shape, and may be another shape such as a corrugated shape (a wave shape) or a trapezoidal shape. InFIG.4, the uneven shape is shown in an emphasized manner.

Second lens module30is an optical component configured to be optically coupled to each tip of the plurality of optical fibers2of cable3held by first lens module5. As shown inFIGS.3andFIGS.5A to5E, second lens module30has a bottom surface31, a first side surface32, a second side surface33, a front end surface34, and a rear end surface35. First side surface32and second side surface33each extend in a direction perpendicular to bottom surface31, and face each other. Front end surface34and rear end surface35each extend in a direction perpendicular to bottom surface31, face each other, and are perpendicular to first side surface32and second side surface33. Second lens module30is mounted on substrate20such that bottom surface31faces main surface21of substrate20.

As shown inFIG.5A, bottom surface31of second lens module30may be provided with second uneven portion36that includes protrusions36aeach having a rectangular cross section in at least a part of a portion where bottom surface31is in contact with adhesion portion40. The height of the protrusion36aof second uneven portion36from bottom surface31(the depth of the depressions36b) may be, for example, from 10 μm to 50 μm. As a portion of adhesion portion40flows into the depressions36bof second uneven portion36, the contact area between bottom surface31of second lens module30and adhesion portion40increases. The shape of second uneven portion36may be another shape, and may be, for example, a shape of modification (one of second uneven portion36A and second uneven portion36B) shown inFIG.5BandFIG.5C, respectively. Second uneven portion36A has a corrugated shape (a wave shape), and second uneven portion36B includes protrusions36ceach having a trapezoidal shape. Accordingly, like second uneven portion36, the contact area between bottom surface31of second lens module30and adhesion portion40is increased in the modification ofFIGS.5B and5C.

Further, the shape of second uneven portion36may be a shape of modification (one of second uneven portion36C and second uneven portion36D) shown inFIG.5DandFIG.5E, respectively. Second uneven portion36C includes depressions36deach having a circular shape, and second uneven portion36D includes depressions36eeach having an inversed trapezoidal shape inverse to protrusion36cof second uneven portion36B. Accordingly, the contact area between bottom surface31of second lens module30and adhesion portion40increases in the modification ofFIGS.5D and5Eand further adhesion portion40that has entered the depressions36d,36eof second uneven portion36C or second uneven portion36D is less likely to come off from the depressions due to the anchor effect. Thus, second lens module30ofFIG.5DorFIG.5Ecan be more reliably fixed to substrate20.

As shown inFIG.2, second lens module30further includes a plurality of light incidence/emission portions30a,a mirror surface30b, and a pair of guide pins30c.Each of the plurality of light incidence/emission portions30ahas an optical axis extending in the X direction on a plane parallel to main surface21of substrate20(see alsoFIGS.5A to5E). The plurality of light incidence/emission portions30aare disposed along the Y direction orthogonal to the X direction on a plane parallel to main surface21. The optical signal emitted from each of the plurality of optical fibers2is incident into second lens module30through a corresponding light incidence/emission portion30a.When light emitting devices (not shown) are provided on substrate20, an optical signal emitted from each light emitting device is emitted from each of the plurality of light incidence/emission portions30avia mirror surface30b, and is incident on each tip of optical fibers2held by first lens module5.

Mirror surface30bis a reflection surface forming an angle of approximately 45 degrees with respect to the X direction and the Z direction. Mirror surface30bis an optical structure for reflecting the light emitted from optical fiber2held by first lens module5by 90° toward light-receiving device (not shown) provided on substrate20. When light emitting devices (not shown) are provided on substrate20, mirror surface30breflects an optical signal propagating in a vertical direction from each light emitting device by 90° toward each optical fiber2. By inserting the pair of guide pins30cinto the pair of guide holes5bof first lens module5, alignment in optical coupling between first lens module5and second lens module30is performed.

Referring back toFIG.3, adhesion portions40will be described. Each adhesion portion40is a member for fixing second lens module30to substrate20. Adhesion portion40is, for example, a thermosetting adhesive. After adhesion portion40is injected into a predetermined position, adhesion portion40is cured by applying heat to fix predetermined members to each other by adhesion. The plurality of adhesion portions40includes two first adhesion portions41, two second adhesion portions42, and two third adhesion portions43. First adhesion portions41are provided at two locations along first side surface32between main surface21of substrate20and a portion of bottom surface31of second lens module30close to first side surface32. Second adhesion portions42are provided at two locations along second side surface33between main surface21of substrate20and a portion of bottom surface31of second lens module30close to second side surface33. Third adhesion portions43are provided between main surface21of substrate20and bottom surface31of second lens module30and along each side surface of front end surface34and rear end surface35. That is, first adhesion portions41, second adhesion portions42, and third adhesion portions43are in contact with main surface21of substrate20and bottom surface31of second lens module30to fix them.

First adhesion portions41and second adhesion portions42are disposed to be line-symmetric with respect to a center line L. The center line L passes through a center of second lens module30in a direction in which first side surface32and second side surface33face each other and extends in a direction parallel to an optical axis of second lens module30. Accordingly, second lens module30is stably fixed to main surface21of substrate20. One of the two first adhesion portions41may be in contact with the other first adhesion portion41. In this case, when viewed from a direction perpendicular to first side surface32, two first adhesion portions41may have two mountain-like shapes, and the bottom portions of the two mountain-like shapes may be in contact with each other, for example. The same applies to two second adhesion portions42.

Next, a method of manufacturing optical module1will be described with reference toFIG.3. In the method of manufacturing optical module1, first, substrate20having main surface21is prepared. Second lens module30having bottom surface31, first side surface32, second side surface33, front end surface34, and rear end surface35is also prepared.

Subsequently, second lens module30is disposed on main surface21of substrate20such that bottom surface31faces main surface21. At this time, the disposition and posture of second lens module30are adjusted such that the optical axis of second lens module30is aligned with the optical axis of another optical component (first lens module5) to be connected to second lens module30in a process to be described later.

Subsequently, when the adjustment of second lens module30is completed, the first adhesive is applied to a plurality of portions (corresponding to first adhesion portions41) along first side surface32, and the second adhesive is applied to a plurality of portions (corresponding to second adhesion portions42) along second side surface33. Each of the first adhesive and the second adhesive is, for example, a thermosetting epoxy-based adhesive, and is applied to a predetermined portion using a dispenser or the like. The first adhesive and the second adhesive are cured by being heated in a process to be described later to become first adhesion portions41and second adhesion portions42, respectively, and fix second lens module30to substrate20.

The first adhesive may be applied between main surface21and a portion of first side surface32close to bottom surface31, and may be applied between main surface21and a portion of bottom surface31close to first side surface32. That is, the first adhesive may be applied between main surface21and at least one of a portion of first side surface32close to bottom surface31and a portion of bottom surface31close to first side surface32. The second adhesive may be applied between main surface21and a portion of second side surface33close to bottom surface31, and may be applied between main surface21and a portion of bottom surface31close to second side surface33. That is, the second adhesive may be applied between main surface21and at least one of a portion of second side surface33close to bottom surface31and a portion of bottom surface31close to second side surface33. In the example shown inFIG.3, the first adhesive is applied between main surface21and a portion of bottom surface31close to first side surface32, and the second adhesive is applied between main surface21and a portion of bottom surface31close to second side surface33. When the adhesive is applied as described above, it is preferable that the first adhesive and the second adhesive are applied to be line-symmetric with respect to center line L of second lens module30. As shown inFIG.3, another adhesive may be applied between main surface21and a portion of bottom surface31close to front end surface34, and another adhesive may be applied between main surface21and a portion of bottom surface31close to rear end surface35. When the adhesive is applied along front end surface34, the adhesive is applied so that the adhesive does not spread to the plurality of light incidence/emission portions30aor the pair of guide pins30c.

Subsequently, when the application of the adhesive such as the first adhesive and the second adhesive is completed, the adhesive such as the first adhesive and the second adhesive is cured. At the time of curing, in the case where the first adhesive, the second adhesive, and the like are thermosetting adhesives, the adhesives such as the first adhesive and the second adhesive can be cured by applying heat. The cured adhesives such as the first adhesive and the second adhesive become first adhesion portions41, second adhesion portions42, and third adhesion portions43, respectively, to fix second lens module30to substrate20.

Subsequently, when the attachment of second lens module30to substrate20is completed, as shown inFIG.2, first lens module5holding the tip portions of the plurality of optical fibers2constituting cable3is connected to second lens module30fixed to substrate20. Thereafter, fitting spring6is set so that the connected first lens module5and second lens module30are fitted into fitting spring6, thereby maintaining the connection state between first lens module5and second lens module30. At this time, second lens module30is firmly fixed to substrate20by the adhesion portions41to43in which the adhesives applied to a plurality of portions are cured. Thus, even if the fitting force of fitting spring6is strong or an external force is applied from first lens module5, second lens module30is not easily separated from substrate20.

Subsequently, first lens module5, second lens module30, substrate20, and the like are interposed between housing upper portion9aand housing lower portion9b,and substrate20and the like are disposed inside metal housing9. Then, metal housing9is disposed inside resin housing10, and front cap11is fitted into the opening of resin housing10. By the manufacturing method described above, optical module1described above is obtained.

Modification

Modification of second lens module30and adhesion portions40(second lens modules30A and30B; and adhesion portions40A and40B) will now be described with reference toFIGS.6and7.FIG.6is a top view of substrate20viewed from above on which second lens module30A according to a first modification is loaded.FIG.7is a side view of second lens module30B according to a second modification. Hereinafter, differences from second lens module30and adhesion portions40of optical module1according to the embodiment will be mainly described, and other descriptions may be omitted.

First, second lens module30A and adhesion portions40A according to the first modification will be described with reference toFIG.6. Second lens module30A has a first side surface32A and a second side surface33A as shown inFIG.6. First side surface32A and second side surface33A are provided with a third uneven portion37aand a third uneven portion37bat portions where first side surface32A and second side surface33A are in contact with adhesion portions40A. Third uneven portions37ais provided on first side surface32A, and third uneven portion37bis provided on second side surface33A.

Adhesion portions40A include two first adhesion portions41A and two second adhesion portions42A. One first adhesion portion41A of the two first adhesion portions41A is provided at a depression of third uneven portion37aclose to front end surface34, and between main surface21and a portion of bottom surface31close to first side surface32A. Another first adhesion portion41A is provided at another depression of third uneven portion37aclose to rear end surface35, and between main surface21and a portion of bottom surface31close to first side surface32A. Accordingly, the contact area between first adhesion portions41A and first side surface32A increases.

One second adhesion portion42A of the two second adhesion portions42A is provided at a depression of third uneven portion37bclose to front end surface34, and between main surface21and the portion of bottom surface31close to second side surface33A. Another second adhesion portion42A is provided at another depression of third uneven portion37bclose to rear end surface35, and between main surface21and a portion of bottom surface31close to second side surface33A. Accordingly, the contact area between second adhesion portions42A and second side surface33A increases.

Next, second lens module30B and adhesion portions40B according to the second modification will be described with reference toFIG.7. Second lens module30B has a first side surface32B and a second side surface33B as shown inFIG.7. First side surface32B and second side surface33B are inclined such that a distance between first side surface32B and second side surface33B decreases gradually away from bottom surface31. That is, front end surface34of second lens module (a cross-section of second lens module30B parallel to front end surface34) has a trapezoidal shape. An angle formed by first side surface32B and bottom surface31and an angle formed by second side surface33B and bottom surface31are, for example, from 70 degrees to 90 degrees.

Similar to adhesion portions40and40A, adhesion portions40B includes two first adhesion portions41B and two second adhesion portions42B. One first adhesion portion41B of the two first adhesion portions41B is provided between main surface21and a portion of first side surface32B close to bottom surface31, and between main surface21and a portion of bottom surface31close to first side surface32B, and is close to front end surface34. Another first adhesion portion41B (not shown) is provided between main surface21and a portion of first side surface32B close to bottom surface31, and between main surface21and a portion of bottom surface31close to first side surface32B, and is close to rear end surface35.

One second adhesion portion42B of the two second adhesion portions42B is provided between main surface21and a portion of second side surface33B close to bottom surface31, and between main surface21and portion of bottom surface31close to second side surface33B, and is close to front end surface34. Other second adhesion portion42B (not shown) is provided between main surface21and a portion of second side surface33B close to bottom surface31, and between main surface21and a portion of bottom surface31close to second side surface33B, and is close to rear end surface35. Since first side surface32B and second side surface33B are inclined surfaces as described above, it is easy to provide first adhesion portions41B and second adhesion portions42B on each side surface. Thus, the contact area between first adhesion portions41B and first side surface32B and the contact area between second adhesion portions42B and second side surface33B can be increased.

As described above, in optical module1according to the embodiments of the present disclosure, first adhesion portions41,41A, and41B are provided at a plurality of locations along first side surfaces32,32A, and32B, and second adhesion portions42,42A, and42B are provided at a plurality of locations along second side surfaces33,33A, and33B. Accordingly, a total area in which substrate20and second lens module30,30A, or30B are adhered to each other by first adhesion portion41,41A, or41B and second adhesion portion42,42A, or42B can be increased. According to optical module1, second lens modules30, and30B can be more firmly adhered to substrate20, and second lens modules30,30A, and30B can be reliably fixed to substrate20. Further, in optical module1, a plurality of first adhesion portions41,41A, and41B and a plurality of second adhesion portions42,42A, and42B are provided, and a region where second lens modules30,30A, and30B are adhered to substrate20is divided into a plurality of regions. Accordingly, when adhesion portions40,40A, and40B are cured, stress acting on each of second lens modules30,30A, and30B is dispersed. According to optical module1, deformation of each of second lens modules30,30A, and30B can be suppressed.

In optical module1, the plurality of first adhesion portions41,41A,41B and the plurality of second adhesion portions42,42A,42B are disposed to be line-symmetric with respect to center line L. Center line L passes through the center of second lens modules30,30A,30B in a direction in which first side surfaces32,32A,32B and corresponding second side surfaces33,33A,33B face each other, and extends in a direction parallel to the optical axis of second lens modules30,30A,30B. Accordingly, second lens modules30,30A, and30B may be more stably fixed to substrate20by first adhesion portions41,41A, and41B and second adhesion portions42,42A, and42B. Therefore, in optical module1, second lens module30,30A, or30B can be more reliably fixed to substrate20.

In optical module1, the plurality of first adhesion portions41,41A, and41B are provided between main surface21and respective portions of bottom surface31close to first side surfaces32,32A, and32B, and the plurality of second adhesion portions42,42A, and42B are provided between main surface21and respective portions of bottom surface31close to second side surfaces33,33A, and33B. Accordingly, even in a state where second lens modules30,30A,30B are disposed on substrate20and second lens modules30,30A,30B are positioned, adhesion portions40,40A,40B can be easily provided along first side surfaces32,32A,32B and second side surfaces33,33A,33B. Therefore, in optical module1, it is possible to easily improve the adhesive force between substrate20and second lens module30,30A, or30B and to easily suppress the deformation of second lens module30,30A, or30B.

In optical module1, main surface21of substrate20is provided with first uneven portion22at least a part of a portion where main surface21is in contact with adhesion portion40. As a result, adhesion portion40flows into the depressions22bof first uneven portion22, and an adhesion area where adhesion portion40and substrate20contact each other can be increased. Therefore, in optical module1, second lens module30can be more reliably fixed to substrate20.

In optical module1, the arithmetic mean roughness Ra of first uneven portion22is equal to or greater than 0.4 μm and equal to or less thna 0.7 μm. When the arithmetic mean roughness Ra of first uneven portion22is 0.4 μm or more, adhesion portion40easily flows into the depressions22bof first uneven portion22, and the adhesion area in which adhesion portion40and substrate20are in contact with each other can be more reliably increased. On the other hand, when the arithmetic mean roughness Ra of first uneven portion22is 0.7 μm or less, it is possible to prevent the optical axis of second lens module30from being deviated when second lens module30is disposed on main surface21of substrate20. Therefore, in optical module1, it is possible to reliably fix second lens module30to substrate20while suppressing deviation of the optical axis or the like.

In, in optical module1, bottom surface31of second lens module30is provided with second uneven portion36at least a part of a portion where bottom surface31is in contact with adhesion portion40. Accordingly, adhesion portion40flows into the depressions36bof second uneven portion36, and an adhesion area where adhesion portion40and second lens module30are in contact with each other can be increased. Therefore, in optical module1, second lens module30can be more reliably fixed to substrate20.

A method of manufacturing optical module1according to the embodiment of the present disclosure includes preparing substrate20having main surface21, preparing second lens module30having bottom surface31, first side surface32, and second side surface33, disposing second lens module30on main surface21of substrate20such that bottom surface31faces main surface21, and fixing second lens module30to substrate20by applying a first adhesive to a plurality of portions along first side surface32, by applying a second adhesive to a plurality of portions along second side surface33, and by curing the first adhesive and the second adhesive. Thus, the contact area between the adhesive and second lens module30and the contact area between the adhesive and substrate20can be increased. In addition, since the number of portions to which the adhesive is applied is increased, stress acting on second lens module30when the adhesive is cured, is dispersed. Therefore, deformation of second lens module30can be suppressed. As described above, according to the method of manufacturing optical module1, it is possible to manufacture optical module1in which the deformation of second lens module30is suppressed while second lens module30is reliably fixed to substrate20.

In the method of manufacturing optical module1according to an embodiment of the present disclosure, in the fixing, the first adhesive may be applied between main surface21and at least one of a portion of first side surface32close to bottom surface31and a portion of bottom surface31close to first side surface32, the second adhesive may be applied between main surface21and at least one of a portion of second side surface33close to bottom surface31and a portion of bottom surface31close to second side surface33, and the first adhesive and the second adhesive may be applied to be line-symmetric with respect to center line L of second lens module30. In this method, second lens module30is more stably fixed to substrate20by the first adhesive and the second adhesive. According to the method of manufacturing optical module1, second lens module30can be more reliably fixed to substrate20.

Although the embodiments of the present disclosure have been described in detail above, the present invention is not limited to the above-described embodiments and can be applied to various embodiments. Although the first modification and the second modification have been described with reference toFIGS.6and7, but a part of these modifications may be applied to the embodiment, or both the first modification and the second modification may be applied to the embodiment. In the above-described embodiment, two adhesion portions are provided along one side surface, but the present invention is not limited thereto. That is, three or more adhesion portions (e.g., first adhesion portion41) may be provided along one side surface (e.g., first side surface32).