JP5550353B2 - Lens array and optical module having the same - Google Patents

Description

  The present invention relates to a lens array and an optical module including the same, and more particularly to a lens array suitable for optically coupling a plurality of light emitting elements and an end face of an optical transmission body, and an optical module including the same.

  In recent years, application of so-called optical interconnection has become widespread as a technique for transmitting signals at high speed within a system apparatus or between apparatuses or between optical modules. Here, the optical interconnection refers to a technology in which an optical component is handled as if it were an electrical component and mounted on a mother board or a circuit board used for a personal computer, a vehicle, an optical transceiver, or the like.

  Optical modules used for such optical interconnections include, for example, internal connections between media converters and switching hubs, optical transceivers, medical equipment, test equipment, video systems, high-speed computer clusters, and other parts within equipment. There are various uses such as.

  In this type of optical module, light including communication information emitted from a light emitting element is coupled to an end face of an optical fiber as an example of an optical transmission body via a lens, thereby allowing communication information via the optical fiber to be transmitted. It was supposed to send.

  In addition, the optical module includes a light receiving element that receives light including communication information propagated through the optical fiber and emitted from the end face of the optical fiber together with the light emitting element so as to support bidirectional communication. There was also.

  Heretofore, in such an optical module, there has been a problem that an appropriate transmission of communication information may be hindered due to a change in the light output characteristics of the light emitting element due to the influence of temperature or the like. It was.

  So far, in this type of optical module, there are various techniques for monitoring (monitoring) light (particularly intensity or light quantity) emitted from the light emitting element in order to stabilize the output characteristics of the light emitting element. It was proposed.

  For example, Patent Document 1 discloses an optical element including a reflection surface (reflection surface portion) for reflecting a part of light emitted from the light emitting element around the lens surface (transmission surface portion) to the light receiving element side as monitor light. Is disclosed.

  In Patent Document 2, a total reflection mirror that totally reflects laser light emitted from a surface emitting laser to the optical fiber side, and a part of the laser light emitted from the surface emitting laser is reflected to the PD side as monitor light. An optical unit having an optical surface in which a notch portion to be connected is provided is disclosed.

JP 2008-151894A Japanese Patent Laying-Open No. 2006-344915 (refer to FIGS. 16A and 16B in particular)

  However, the configuration described in Patent Document 1 has a problem that it is difficult to effectively apply multi-channel optical communication in a compact configuration. That is, in recent years, a demand for a lens array in which a plurality of lenses are aligned in a predetermined alignment direction is increasing as a small optical component that realizes multi-channel optical communication. In this type of lens array, a light emitting device in which a plurality of light emitting elements are aligned is arranged so that each light emitting element faces each lens surface on the incident side of the lens array, and a plurality of optical fibers are arranged in the lens array. Multi-channel optical communication by arranging the light emitted from each light emitting element to face each lens surface on the emission side and optically coupling the light emitted from each light emitting element to the end surface of each optical fiber by each lens of the lens array ( Send). Even in such a lens array, it is very important to monitor the light emitted from the light emitting element from the viewpoint of securing the stability of optical communication. Not only are each formed with a very small diameter, but the lenses adjacent to each other are formed with a very narrow pitch. It has been difficult to form a reflecting surface for reflecting monitor light around the periphery.

  In addition, the configuration described in Patent Document 2 has a problem that it is difficult to manufacture because the positional accuracy of the boundary between the total reflection mirror and the notch is required.

  Accordingly, the present invention has been made in view of such problems, and provides a lens array that can reliably obtain monitor light and can be easily manufactured, and an optical module including the lens array. It is intended to do.

In order to achieve the above object, the lens array according to claim 1 of the present invention is characterized in that a plurality of light emitting elements are formed in alignment and light emitted from at least one of the plurality of light emitting elements is monitored. Between the photoelectric conversion device having at least one first light receiving element for receiving the monitor light and an optical transmission body, and optically connecting the plurality of light emitting elements and the end face of the optical transmission body A lens array that can be coupled, and is formed on a first surface of the lens array body facing the photoelectric conversion device so as to be aligned in a predetermined alignment direction corresponding to the plurality of light emitting elements. A plurality of first lens surfaces on which light emitted from each light emitting element is incident, and an end surface of the optical transmission body in the lens array body, and are formed perpendicular to the first surface. 2 is formed so as to be aligned along the alignment direction of the first lens surface, and the light for each of the plurality of light emitting elements respectively incident on the plurality of first lens surfaces is transmitted to the optical transmission body. A plurality of second lens surfaces that are respectively emitted toward the end surface of the lens array, and the first surface of the lens array body, and the monitor light incident from the inner side of the lens array body is the first light receiving light. The first lens surface and the second lens surface are arranged on at least one third lens surface that emits light toward the element, and on a third surface that faces the first surface of the lens array body. A recess formed to be located on the optical path to be connected and a part of the inner surface of the recess, and away from the second surface as the distance from the first surface increases with respect to the second surface. It has a tilt angle A first optical surface on which light for each of the plurality of light emitting elements incident on the plurality of first lens surfaces is incident from an incident direction perpendicular to the second surface, and an inner surface of the recess And forming a portion facing the first optical surface and having a predetermined inclination angle with respect to the second surface, and after being incident on the first optical surface, Between the first optical surface and the first optical surface in the lens array body, the second optical surface on which the light of each of the plurality of light emitting elements that has traveled toward the second lens surface is incident A total reflection surface arranged on the optical path of the light for each of the plurality of light emitting elements and totally reflecting the light for each of the plurality of light emitting elements incident on the first lens surface toward the first optical surface And disposed on or in the vicinity of the first optical surface, The light of each of the plurality of light emitting elements incident on one optical surface is reflected to the third lens surface side with a predetermined reflectance and transmitted to the second optical surface side with a predetermined transmittance. In this case, the first reflection / transmission layer that reflects at least one of the light of each of the plurality of light emitting elements as the monitor light, and the downward movement into the upwardly open space formed by the concave portion, and without gaps. When the tilt angle of the first optical surface is θ [°], the tilt angle of the second optical surface is 180−θ. [°], an optical path between the total reflection surface on the incident side of the light for each of the plurality of light emitting elements with respect to the first optical surface and the first optical surface, and for each of the plurality of light emitting elements The optical path on the exit side of the light with respect to the second optical surface is positioned on the same straight line. There to that point.

According to the first aspect of the present invention, the light of each light emitting element incident on the first lens surface is separated from the second lens surface side and the third lens surface side by the first reflection / transmission layer. The monitor light that has been split into the first and second lens surfaces can be emitted to the first light-receiving element side by the third lens surface, so that the monitor light can be reliably obtained, and By adopting the first reflection / transmission layer having a certain area as a configuration for obtaining such monitor light, it is possible to facilitate the manufacturing of the lens array. Further, the optical path between the total reflection surface on the incident side with respect to the first optical surface and the first optical surface and the optical path on the emission side with respect to the second optical surface can be positioned on the same straight line, Moreover, such an optical path arrangement can be easily realized by setting the lens array body and the filler to the same refractive index. As a result, with a simple configuration, when it is confirmed that the light incident on the second lens surface is deviated from the center of the second lens surface during product inspection, dimensional adjustment is performed to eliminate this. The number of necessary portions can be reduced, and the position of the second lens surface can be easily determined during the design, thereby contributing to further facilitation of manufacturing. In addition, the plurality of light incident on the first lens surface is disposed on an optical path of light for each of the plurality of light emitting elements between the first lens surface and the first optical surface in the lens array body. And a total reflection surface that totally reflects the light for each light emitting element toward the first optical surface, and the first lens surface and the third lens surface are facing the photoelectric conversion device. Since it arrange | positions on a surface (1st surface), the compact design which is reasonable when the light for each light emitting element which injected into the 1st lens surface advances to the recessed part side is attained. Further, the first optical surfaces (surfaces inclined to the second surface) that face each other and form a part of the inner surface of the recess formed in the third surface that faces the first surface. The concave portion is formed in a cross-sectional shape (substantially V-shaped) that gradually expands toward the third surface by the second optical surface (a surface that is 180 degrees different from the first optical surface). As a result, the prism has substantially the same cross-sectional shape (substantially triangular) as the concave portion.

  The lens array according to claim 2 is characterized in that, in claim 1, the optical transmission body is further formed so as to emit light toward the lens array main body, and the second lens surface includes: The photoelectric conversion device includes a second light receiving element that receives the light emitted from the optical transmission body, and is formed so that the light emitted from the optical transmission body is incident thereon. A fourth lens surface is formed at a position facing the second light receiving element to emit light emitted from the optical transmission body incident from the inner side of the lens array body toward the second light receiving element. The light emitted from the optical transmission body incident on the second lens surface on or near the second optical surface is reflected to the fourth lens surface side with a predetermined reflectance and is predetermined. Second reflection to transmit with a transmittance of Lies in the transmission layer is formed.

  According to the second aspect of the present invention, the light emitted from the optical transmission body can be coupled to the second light receiving element by the second reflection / transmission layer and the fourth lens surface. With this configuration, bidirectional optical communication (for example, BiDi: bi-directional) can be handled, and convenience can be improved.

Further, features of the lens array according to claim 3, in claim 1, further pre Symbol the first reflective / transmissive layer, a first optical plate parallel predetermined refractive index on the first optical surface A second optical plate having the same refractive index as that of the first optical plate parallel to the second optical surface is disposed on or in the vicinity of the second optical surface; The optical plate includes an optical path inside the filler of the light for each of the plurality of light emitting elements generated by being refracted when the light for each of the plurality of light emitting elements is incident on the first optical plate, and the first optical plate. The optical path on the exit side with respect to the second optical surface is eliminated from the direction perpendicular to the optical path length direction with respect to the optical path in the predetermined range on the incident side with respect to the first optical surface, and the incident side with respect to the first optical surface is The optical path is adjusted so as to be positioned on the same straight line as the predetermined range of the optical path.

  According to the third aspect of the present invention, the first reflection / transmission layer is directly formed on the first optical surface by forming the first reflection / transmission layer on the first optical plate. Compared with the case where it does, the 1st reflection / transmission layer can be formed easily. Further, even when the first optical plate is arranged on the optical path of the light for each light emitting element in this way, the influence of refraction (optical path deviation) by the first optical plate is reduced to the second optical plate. Since it can be eliminated by the plate, it is possible to ensure linearity between the light path on the incident side with respect to the first optical surface and the light path on the output side with respect to the second optical surface.

Furthermore, features of the lens array according to claim 4, in claim 2, further pre Symbol the first reflective / transmissive layer, a first optical predetermined refractive index parallel to the first optical surface The second reflection / transmission layer is formed on a second optical plate having the same refractive index as that of the first optical plate parallel to the second optical surface, and the second reflection / transmission layer is formed on the second optical plate. The optical plate includes an optical path inside the filler of the light for each of the plurality of light emitting elements generated by being refracted when the light for each of the plurality of light emitting elements is incident on the first optical plate, and the first optical plate. The optical path on the exit side with respect to the second optical surface is eliminated from the direction perpendicular to the optical path length direction with respect to the optical path in the predetermined range on the incident side with respect to the first optical surface, and the incident side with respect to the first optical surface is The optical path is adjusted so as to be positioned on the same straight line as the predetermined range of the optical path.

  According to the fourth aspect of the present invention, the first reflective / transmissive layer is formed directly on the first optical surface by forming the first reflective / transmissive layer on the first optical plate. Compared with the case where it does, the 1st reflection / transmission layer can be formed easily. Further, the second reflection / transmission layer is formed on the second optical plate, so that the second reflection / transmission layer is formed on the second optical surface as compared with the case where the second reflection / transmission layer is formed directly on the second optical surface. / The transmission layer can be easily formed. Further, even when the first optical plate is arranged on the optical path of light for each light emitting element, the influence of refraction (optical path deviation) by the first optical plate is eliminated by the second optical plate. Therefore, it is possible to ensure linearity between the light path on the incident side with respect to the first optical surface and the light path on the emission side with respect to the second optical surface.

  The lens array according to claim 5 is characterized in that, in claim 3 or 4, the filler is made of a translucent adhesive, and the first optical plate and the second optical plate are , And is adhered to the lens array body by the filler.

  According to the fifth aspect of the present invention, the filler can also serve as an adhesive that bonds the first optical plate and the second optical plate to the lens array body, thereby reducing costs. it can.

  Further, the lens array according to claim 6 is characterized in that in any one of claims 3 to 5, the first optical plate further includes the first optical sheet via a first adhesive sheet having a predetermined refractive index. The second optical plate is affixed to the second optical surface via a second adhesive sheet having the same refractive index as that of the first adhesive sheet. is there.

  According to the sixth aspect of the invention, the first optical plate and the second optical plate can be more stably fixed to the lens array body.

The lens array according to a seventh aspect is characterized in that, in any one of the first to sixth aspects, the inclination angle of the first optical surface is 135 [°], and the second The tilt angle of the optical surface is 45 [°], the total reflection surface is formed parallel to the second optical surface, and the optical axis on each lens surface formed on the first surface is The optical axis on the second lens surface is formed perpendicular to the second surface, and the optical axis on the second lens surface is formed perpendicular to the second surface.

According to the seventh aspect of the present invention, the shape of the lens array body can be made suitable for further simplification of design and measurement of dimensional accuracy.

Furthermore, the optical module according to an eighth aspect is characterized in that the lens array according to any one of the first to seventh aspects and the photoelectric conversion device according to the first or second aspect are provided.

According to the eighth aspect of the present invention, monitor light can be obtained reliably and manufacturing can be facilitated.

  According to the present invention, monitor light can be obtained with certainty and manufacturing can be facilitated.

1 is a schematic configuration diagram showing an outline of an optical module together with a longitudinal sectional view of the lens array in a first embodiment of a lens array and an optical module including the same according to the present invention. Plan view of the lens array shown in FIG. Left side view of the lens array shown in FIG. Right side view of the lens array shown in FIG. Bottom view of the lens array shown in FIG. In the modification of 1st Embodiment, the schematic block diagram which shows the outline | summary of an optical module with the longitudinal cross-sectional view of a lens array Plan view of the lens array shown in FIG. Left side view of FIG. Right side view of FIG. Bottom view of FIG. In 2nd Embodiment of the lens array which concerns on this invention, and an optical module provided with the same, the schematic block diagram which shows the outline | summary of an optical module with the longitudinal cross-sectional view of a lens array In 3rd Embodiment of the lens array which concerns on this invention, and an optical module provided with the same, the schematic block diagram which shows the outline | summary of an optical module with the longitudinal cross-sectional view of a lens array The bottom view of the lens array shown in FIG. In the modification of 3rd Embodiment, the schematic block diagram which shows the outline | summary of an optical module with the longitudinal cross-sectional view of a lens array In 4th Embodiment of the lens array which concerns on this invention, and an optical module provided with the same, the schematic block diagram which shows the outline | summary of an optical module with the longitudinal cross-sectional view of a lens array In 5th Embodiment of the lens array which concerns on this invention, and an optical module provided with the same, the schematic block diagram which shows the outline | summary of an optical module with the longitudinal cross-sectional view of a lens array

(First embodiment)
Hereinafter, a first embodiment of a lens array and an optical module including the same according to the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic configuration diagram showing an outline of an optical module 1 in the present embodiment together with a longitudinal sectional view of a lens array 2 in the present embodiment. FIG. 2 is a plan view of the lens array 2 shown in FIG. FIG. 3 is a left side view of the lens array 2 shown in FIG. FIG. 4 is a right side view of the lens array 2 shown in FIG. FIG. 5 is a bottom view of the lens array 2 shown in FIG.

  As shown in FIG. 1, the lens array 2 in the present embodiment is arranged between a photoelectric conversion device 3 and an optical fiber 5.

  Here, the photoelectric conversion device 3 emits (emits) laser beams L having the same wavelength toward the surface facing the lens array 2 in the semiconductor substrate 6 in a direction perpendicular to the surface (upward direction in FIG. 1). The light emitting elements 7 constitute a vertical cavity surface emitting laser (VCSEL). In FIG. 1, the light emitting elements 7 are aligned and formed along the direction perpendicular to the paper surface in FIG. 1. Further, the photoelectric conversion device 3 is a surface facing the lens array 2 in the semiconductor substrate 6, and the output of the laser light L emitted from each light emitting element 7 in the vicinity of the left part in FIG. A plurality of first light receiving elements 8 having the same number as the light emitting elements 7 for receiving the monitor light M for monitoring (for example, intensity and light quantity) are provided. The first light receiving elements 8 are aligned and formed in the same direction as the light emitting elements 7, and the positions in the alignment direction coincide with each other between the elements 7 and 8 corresponding to each other. That is, the first light receiving elements 8 are formed at the same pitch as the light emitting elements 7. The first light receiving element 8 may be a photodetector. Further, although not shown, the photoelectric conversion device 3 outputs the output of the laser light L emitted from the corresponding light emitting element 7 based on the intensity and the light amount of the monitor light M received by each first light receiving element 8. A control circuit for controlling is connected. For example, such a photoelectric conversion device 3 is arranged to face the lens array 2 so that a contact portion to the lens array 2 (not shown) is in contact with the lens array 2. The photoelectric conversion device 3 is attached to the lens array 2 by a known fixing means.

  Further, the same number of the optical fibers 5 in the present embodiment as the light emitting elements 7 and the first light receiving elements 8 are arranged. In FIG. Has been. The optical fibers 5 are aligned with the light emitting elements 7 at the same pitch. Each optical fiber 5 is attached to the lens array 2 by a known fixing means in a state where the portion on the end face 5a side is held in the multi-core collective connector 10.

  The lens array 2 optically couples each light emitting element 7 and the end face 5a of each optical fiber 5 in a state of being arranged between the photoelectric conversion device 3 and the optical fiber 5 as described above. ing.

  The lens array 2 will be described in more detail. As shown in FIG. 1, the lens array 2 has a lens array main body 4, and the lens array main body 4 is formed in a trapezoidal outer shape in the longitudinal section. Moreover, as shown in FIG. 2, the planar shape is formed in a substantially rectangular shape, and as shown in FIGS. 3 and 4, the side surface shape is formed in a rectangular shape.

  As shown in FIGS. 1 and 5, the lens array 2 has the same number of light emitting elements 7 on the lower end surface 4 a (plane) of FIG. 1 facing the photoelectric conversion device 3 in the lens array body 4 as the first surface. A plurality of (eight) planar circular first lens surfaces (convex lens surfaces) 11 are provided. The plurality of first lens surfaces 11 are formed so as to be aligned in a predetermined alignment direction corresponding to the light emitting element 7 (the vertical direction in FIG. 1 and the vertical direction in FIG. 5). The first lens surfaces 11 are formed at the same pitch as the light emitting elements 7. The optical axis OA (1) on each first lens surface 11 coincides with the central axis of the laser light L emitted from each light emitting element 7 corresponding to each first lens surface 11. Is desirable.

  As shown in FIG. 1, the laser light L emitted from each light emitting element 7 corresponding to each first lens surface 11 is incident on each first lens surface 11. Each first lens surface 11 collimates the incident laser light L for each light emitting element 7 and then advances it into the lens array body 4.

  As shown in FIGS. 1 and 3, the lens array 2 has a first end face 4b (plane) in FIG. 1 facing the end face 5a of the optical fiber 5 in the lens array body 4 as the second face. The same number of second lens surfaces (convex lens surfaces) 12 as the lens surfaces 11 are provided. The plurality of second lens surfaces 12 are formed so as to be aligned in the same direction as the alignment direction of the first lens surfaces 11. Each second lens surface 12 is formed at the same pitch as the first lens surface 11. The optical axis OA (2) on each second lens surface 12 is desirably arranged coaxially with the central axis of the end surface 5a of each optical fiber 5 corresponding to each second lens surface 12. .

  As shown in FIG. 1, each such second lens surface 12 is incident on each first lens surface 11 corresponding to each second lens surface 12 to enter the optical path inside the lens array body 4. The laser light L for each light-emitting element 7 that has traveled through is incident with its central axis aligned with the optical axis OA (2) on each second lens surface 12. Then, each second lens surface 12 emits the laser beam L for each incident light emitting element 7 toward the end surface 5 a of each optical fiber 5 corresponding to each second lens surface 12.

  In this way, each light emitting element 7 and the end face 5 a of each optical fiber 5 are optically coupled via the first lens surface 11 and the second lens surface 12.

  Further, as shown in FIGS. 1 and 5, the same number of first light receiving elements 8 as the number of the first light receiving elements 8 in the lower end surface 4a of the lens array body 4 with respect to the first lens surface 11 as shown in FIG. 3, the same number of light emitting elements 7, optical fibers 5, first lens surfaces 11, and second lens surfaces 12 as the third lens surfaces 13 are formed. Each third lens surface 13 is formed to align in a predetermined alignment direction corresponding to the first light receiving element 8, that is, in the same direction as the alignment direction of the first lens surface 11. The third lens surfaces 13 are formed at the same pitch as the first light receiving elements 8. It is desirable that the optical axis OA (3) on each third lens surface 13 coincides with the central axis of the light receiving surface of each first light receiving element 8 corresponding to each third lens surface 13.

  As shown in FIG. 1, monitor light M for each light emitting element 7 corresponding to each third lens surface 13 is incident on each third lens surface 13 from the inside of the lens array body 4. To do. Each third lens surface 13 emits the incident monitor light M for each light emitting element 7 toward each first light receiving element 8 corresponding to each third lens surface 13.

  Furthermore, as shown in FIGS. 1 and 4, the lens array body 4 has a total reflection surface 4d at the upper right end in FIG. 1, and the total reflection surface 4d has its upper end at its lower end. It is formed in the inclined surface located in the left side in FIG. 1 (namely, the recessed part 14 side mentioned later) rather than a part. The total reflection surface 4d is disposed on the optical path of the laser light L for each light emitting element 7 between the first lens surface 11 and the first optical surface 14a of the concave portion 14 described later.

  As shown in FIG. 1, the laser beam L for each light emitting element 7 after being incident on each first lens surface 11 has a critical angle or more from the lower side in FIG. Incident at an incident angle. The total reflection surface 4d totally reflects the incident laser light L for each light emitting element 7 toward the left side in FIG.

  A reflective film made of Au, Ag, Al or the like may be coated on the total reflection surface 4d.

  Further, as shown in FIGS. 1 and 2, a concave portion 14 is formed on the upper end surface 4c (plane) of FIG. 1 in the lens array body 4 as the third surface, and the first lens surface 11 and the second lens. A recess is formed so as to be positioned on the optical path connecting the surface 12. The upper end surface 4c is formed in parallel to the lower end surface 4a.

  Here, as shown in FIG. 1, the recess 14 has a first optical surface 14 a that forms a part of the inner surface (the right side surface of the recess 14 in FIG. 1). The first optical surface 14a is an inclined surface having a predetermined inclination angle with respect to the left end surface 4b, the upper end portion of which is located on the right side (that is, the total reflection surface 4d side) in FIG. Is formed.

  As shown in FIG. 1, the laser light L for each light emitting element 7 totally reflected by the total reflection surface 4d is incident on the first optical surface 14a at a predetermined incident angle. However, the incident direction of the laser light L for each light emitting element 7 on the first optical surface 14a is perpendicular to the left end surface 4b.

  Moreover, as shown in FIG. 1, the recessed part 14 is a part of the inner surface, and opposes the left side of FIG. 1 with respect to the first optical surface 14a (the left side surface of the recessed part 14 in FIG. 1). And the second optical surface 14b has a predetermined inclination angle with respect to the left end surface 4b.

  However, in the present embodiment, the inclination angle of the second optical surface 14b with respect to the left end surface 4b as a reference (0 °) is the inclination angle of the first optical surface 14a with respect to the left end surface 4b as θ [°]. Then, it is expressed as 180−θ [°]. That is, in the present embodiment, the first optical surface 14a and the second optical surface 14b have a line-symmetric shape with respect to a symmetry axis AS perpendicular to the lower end surface 4a indicated by a two-dot chain line in FIG. .

  Further, as shown in FIG. 1, a thin first reflection / transmission layer 17 having a uniform thickness is disposed on the first optical surface 14a. The surface of the first reflective / transmissive layer 17 on the first optical surface 14a side is in close contact with the first optical surface 14a.

  Furthermore, as shown in FIG. 1, the first reflection / transmission layer 17 is formed on the first optical plate 15 (the lower surface in FIG. 1) over the first optical surface 14a. Is arranged. Here, as shown in FIG. 1, the first optical plate 15 is formed in a flat plate shape having a uniform thickness parallel to the first optical surface 14 a and the first optical plate 15. It is formed with a predetermined refractive index according to the material. The size of the first optical plate 15 in the direction perpendicular to the paper surface in FIG. 1 is such that all of the laser light L for each light emitting element 7 can enter.

  Also, as shown in FIG. 1, a second optical plate 16 is disposed on the second optical surface 14b, and the second optical plate 16 is a surface on the second optical surface 14b side. Is in close contact with the second optical surface 14b. As shown in FIG. 1, the second optical plate 16 is formed in a flat plate shape having a uniform thickness parallel to the second optical surface 14 b and has the same refraction as the first optical plate 15. Is formed at a rate. The size of the second optical plate 16 in the direction perpendicular to the plane of FIG. 1 is such that all of the laser light L for each light emitting element 7 can enter. Note that the second optical plate 16 may be made of the same material as the first optical plate 15. In the present embodiment, the second optical plate 16 is formed to have the same air conversion length as that of the first optical plate 15.

  Further, as shown in FIG. 1, in the space formed by the concave portion 14, a filler 18 having the same refractive index as that of the lens array body 4 covers the first optical plate 15 and the second optical plate 16 from substantially above. Thus, the recess 14 is filled with no gap.

  Furthermore, in this embodiment, the filler 18 is made of a translucent adhesive, and the first optical plate 15 and the second optical plate 16 are attached to the lens array body 4 by the adhesive force of the filler 18. It is glued. As the filler 18 serving also as such an adhesive, an ultraviolet curable resin or a thermosetting resin having the same refractive index as the lens array body 4 can be used. As a more specific example, when the lens array body 4 is formed of ARTON (registered trademark) manufactured by JSR as a cyclic olefin resin, the filler 18 is manufactured by TEX Co., Ltd. as a UV curable resin. A1754B can be used. In both ARTON and A1754B, the refractive index for light with a wavelength of 850 nm calculated based on the refractive index for the d-line and the Abbe number disclosed by the manufacturer is 1.50. However, the material of the filler 18 and the lens array body 4 is not limited to these.

  The first reflection / transmission layer 17, the first optical plate 15, the filler 18 and the second optical plate 16 thus arranged in the recess 14 are each for each light emitting element 7 as shown below. The laser beam L is provided with a spectroscopic function and an optical path adjusting function for coupling the end face 5a of the optical fiber 5 to the first light receiving element 8.

  That is, first, as shown in FIG. 1, the laser light L for each light emitting element 7 incident on the first optical surface 14a is incident on the first reflection / transmission layer 17 immediately thereafter. The first reflection / transmission layer 17 reflects the incident laser light L for each light emitting element 7 to the third lens surface 13 side with a predetermined reflectance, and also has the first transmittance with a predetermined transmittance. The light is transmitted to the optical plate 15 side.

  At this time, as shown in FIG. 1, the first reflection / transmission layer 17 is a part of each of the laser beams L incident on the first reflection / transmission layer 17 (the reflectance component). Light) is reflected toward each third lens surface 13 corresponding to each monitor light M as monitor light M for each light emitting element 7 corresponding to each light emitting element 7.

  Then, the monitor light M for each light emitting element 7 reflected by the first reflection / transmission layer 17 in this way travels inside the lens array body 4 toward the third lens surface 13 side. The light is emitted from each third lens surface 13 toward each corresponding first light receiving element 8.

Here, for example, when the first reflection / transmission layer 17 is formed by coating a single layer film of Cr on the first optical plate 15 using a known coating technique, for example, The reflectance of the reflective / transmissive layer 17 can be 30%, and the transmittance can be 30% (absorption rate 40%). The first reflection / transmission layer 17 may be formed of a single layer film of a single metal other than Cr such as Ni or Al. Further, when the first reflective / transmissive layer 17 is formed by coating a known dielectric multilayer film made of TiO ₂ , SiO ₂ or the like on the first optical plate 15 using a known coating technique. For example, the reflectance of the first reflective / transmissive layer 17 can be 20% and the transmittance can be 80%. In addition to this, the reflectance and transmittance of the first reflection / transmission layer 17 are as long as the monitor light M having an amount of light that is considered sufficient for monitoring the output of the laser light L can be obtained. A desired value can be set according to the material, thickness, etc. of one reflection / transmission layer 17. Further, a coating technique such as inconel deposition may be used for coating the first reflective / transmissive layer 17. Further, for example, the first reflection / transmission layer 17 may be configured by a glass filter.

  On the other hand, the laser beam L for each light emitting element 7 transmitted by the first reflection / transmission layer 17 passes through the first optical plate 15 and then enters the filler 18. Then, the laser light L for each light emitting element 7 incident on the filler 18 travels on the optical path inside the filler 18 toward the second lens surface 12 side.

  At this time, since the filler 18 is formed to have the same refractive index as that of the lens array body 4, the optical path of the laser light L for each light emitting element 7 in the filler 18 is different from that of the total reflection surface 4 d and the first. It is maintained parallel to the optical path of the laser beam L connecting the optical surface 14a.

  This will be described in detail. First, the first optical surface 14 a, the interface between the first reflection / transmission layer 17 and the first optical plate 15, and the interface between the first optical plate 15 and the filler 18 are provided. The following equations (1) and (2) based on Snell's law are established on the assumption that they are parallel to each other.

n ₁ sin θ ₁ = n ₂ sin θ ₂ (1)
n ₂ sin θ ₂ = n ₁ sin θ ₃ (2)

However, in the formulas (1) and (2), n ₁ is the refractive index of the lens array body 4 and the filler 18, and n ₂ is the refractive index of the first optical plate 15. These n ₁ and n ₂ are both based on light of the same wavelength. Further, θ ₁ in the expression (1) is an incident angle of the laser light L for each light emitting element 7 with respect to the first optical surface 14a. Further, θ ₂ in the equations (1) and (2) is an emission angle of the laser light L for each light emitting element 7 from the interface between the first reflection / transmission layer 17 and the first optical plate 15. The incident angle of the laser beam L for each light emitting element 7 with respect to the interface between the first optical plate 15 and the filler 18. However, since the thickness (dimension in the optical path direction) of the first reflection / transmission layer 17 is extremely thin as compared with the lens array body 4, the first optical plate 15, and the filler 18, the first The refraction of the laser light L in the reflection / transmission layer 17 is ignored. Further, θ ₃ in the expression (2) is an emission angle of the laser light L for each light emitting element 7 from the interface between the first optical plate 15 and the filler 18. References (0 °) of θ _{1 to} θ ₃ are all set in the surface normal direction of the first optical surface 14a.

  Here, since the right side of the formula (1) and the left side of the formula (2) are common, the following formula is derived.

n ₁ sin θ ₁ = n ₁ sin θ ₃ (3)

Then, from the equation (3), θ ₃ = θ ₁ is obtained. This means that the optical path of the laser light L for each light emitting element 7 inside the filler 18 is parallel to the optical path of the laser light L connecting the total reflection surface 4d and the first optical surface 14a. It is none other than what is shown.

  Thus, the laser light L for each light emitting element 7 that has traveled on the optical path in the filler 18 while maintaining parallelism to the optical path of the laser light L connecting the total reflection surface 4d and the first optical surface 14a is As shown in FIG. 1, after passing through the second optical plate 16, it enters the second optical surface 14 b and returns to the optical path inside the lens array body 4.

  At this time, it is assumed that the interfaces of the second optical surface 14b and the filler 18 and the second optical plate 16 are parallel to each other, and the second optical surface b is line-symmetric with the first optical surface 14a. The following equations (4) and (5) are established based on Snell's law.

n ₁ sin θ ₁ = n ₂ sin θ ₂ (4)
n ₂ sin θ ₂ = n ₁ sin θ ₄ (5)

However, in the expressions (4) and (5), n ₁ is the refractive index of the lens array body 4 and the filler 18 as in the expressions (1) to (3). Further, n ₂ is the refractive index of the second optical plate 16, and this n ₂ is also the refractive index of the first optical plate 15, as described in the description of the expressions (1) and (2). is there. Further, θ ₁ in the equation (4) is an incident angle of the laser light L for each light emitting element 7 with respect to the interface between the filler 18 and the second optical plate 16, and this θ ₁ is the first optical plate 15. This is also the emission angle of the laser light L for each light emitting element 7 from the interface between the filler 18 and the filler 18 as described in the description of the expression (3). Further, θ ₂ in the expressions (4) and (5) is an emission angle of the laser light L for each light emitting element 7 from the interface between the filler 18 and the second optical plate 16, and the second optical The incident angle of the laser light L for each light emitting element 7 with respect to the surface 14b (in other words, the interface between the second optical plate 16 and the second optical surface 14b). This θ ₂ is an emission angle of the laser light L for each light emitting element 7 from the interface between the first reflection / transmission layer 17 and the first optical plate 15, and the first optical plate 15 and the filler It is also the incident angle of the laser light L for each light emitting element 7 with respect to the interface with 18 as described in the explanation of the expressions (1) and (2). Further, θ ₄ in the equation (5) is an emission angle of the laser light L for each light emitting element 7 from the second optical surface 14b. Note that the reference (0 °) of θ ₁ , θ _2, and θ _{4 in} the equations (4) and (5) are all in the surface normal direction of the second optical surface 14b.

  Here, since the right side of the equation (4) and the left side of the equation (5) are common, the following equation is derived.

n ₁ sin θ ₁ = n ₁ sin θ ₄ (6)

Then, from the equation (6), θ ₄ = θ ₁ is obtained. This means that the optical path of the laser light L for each light emitting element 7 after the second optical surface 14b is parallel to the optical path of the laser light L for each light emitting element 7 inside the filler 18. It is none other than what is shown.

  Here, the optical path of the laser light L for each light emitting element 7 inside the filler 18 is parallel to the optical path of the laser light L connecting the total reflection surface 4d and the first optical surface 14a. As mentioned above. From this, first, the optical path of the laser light L for each light emitting element 7 after the second optical surface 14b is parallel to the optical path of the laser light L connecting the total reflection surface 4d and the first optical surface 14a. It can be said that.

  Furthermore, the first optical surface 14a and the second optical surface 14b are axisymmetric, the first optical plate 15 and the second optical plate 16 have the same air conversion length, and the reflection / transmission layer 17. If the thickness of the first optical surface 14a is negligible and the laser light L for each light emitting element 7 is incident on the first optical surface 14a from a direction perpendicular to the axis of symmetry AS, the laser light after the second optical surface 14b is considered. It can be said that the L optical path is located on the same straight line with respect to the optical path of the laser light L connecting the total reflection surface 4d and the first optical surface 14a.

That is, in the present embodiment, the laser light L for each light emitting element 7 incident on the first optical surface 14 a at the incident angle θ ₁ is refracted at the refraction angle θ ₂ when entering the first optical plate 15. 1, and by this refraction, the optical path of the laser beam L for each optical element 7 connecting the total reflection surface 4d and the first optical surface 14a, and the optical path inside the filler 18 In the meantime, a deviation (so-called lateral deviation) in a direction perpendicular to the optical path length direction (lateral direction in FIG. 1) occurs. However, in the present embodiment, the laser light L for each light emitting element 7 that has traveled the optical path in the filler 18 is refracted at the refraction angle θ ₂ when entering the second optical plate 16 and is shown in FIG. after traveling to the lower left, by being emitted at emission angle theta ₁ from the second optical surface 14b, it is possible to eliminate lateral displacement. This is because the optical path of the laser light L for each light-emitting element 7 after the second optical surface 14b is caused by the second optical plate 16 to connect the total reflection surface 4d and the first optical surface 14a. That is, the optical path of the laser beam L is adjusted so as to be positioned on the same straight line with respect to the optical path.

  The laser light L for each light emitting element 7 that has returned from the second optical surface 14b onto the optical path inside the lens array body 4 in this way passes through the second lens surface along the optical path inside the lens array body 4. After traveling toward the side 12, the light is emitted by the second lens surfaces 12 toward the end surfaces 5 a of the corresponding optical fibers 5.

  According to the above configuration, the laser light L for each light emitting element 7 incident on the first lens surface 11 is caused to be on the second lens surface 12 side and each third lens by the first reflection / transmission layer 17. The monitor light M that is dispersed on the surface 13 side and dispersed on each third lens surface 13 side can be emitted to each first light receiving element 8 side by each third lens surface 13. As a result, the monitor light M can be reliably obtained, and the first reflection / transmission layer 17 having a certain area and easy to form is employed as a configuration for obtaining such monitor light M. Thus, the lens array 2 can be easily manufactured.

  Further, according to the present embodiment, an optical path in a predetermined range on the incident side with respect to the first optical surface 14a (an optical path between the total reflection surface 4d and the first optical surface 14a) and an emission with respect to the second optical surface 14b. Since the linearity with the optical path on the side can be ensured, for example, during product inspection, the laser light L for each light emitting element 7 incident on each second lens surface 12 is emitted from each of the two lens surfaces 12. When it is confirmed that the center is deviated from the center, it is possible to reduce the number of places that require dimensional adjustment to correct this. The dimension adjustment can include changing the shape of the mold. Specifically, in the case of a design in which the linearity between the light path on the incident side with respect to the first optical surface 14a and the light path on the output side with respect to the second optical surface 14b cannot be secured, In order to correct the axial deviation of the incident light within an allowable limit, it may be necessary to reset the optimum inclination angle separately on both optical surfaces 14a and 14b of the concave portion 14 independently. On the other hand, in this embodiment, if the total reflection direction in the total reflection surface 4d is perpendicular to the left end surface 4b and the line symmetry of both the optical surfaces 14a and 14b is ensured, both the optical surfaces. There is no need for complicated and complicated dimensional adjustments such that the inclination angles that have no correlation with each other at 14a and 14b are appropriately set by trial and error. Further, if the linearity between the light path on the incident side with respect to the first optical surface 14a and the light path on the output side with respect to the second optical surface 14b can be ensured, the position of the second lens surface 12 can be easily determined at the time of design. can do.

  Thereby, it can contribute to the simplification of the manufacture of the lens array 2 further.

  As described above, if the first reflection / transmission layer 17 is formed by coating a single metal single layer film or a dielectric multilayer film on the first optical plate 15, the first reflection / transmission layer 17 is formed. / Since the structure and manufacturing process of the transmission layer 17 can be simplified, further ease of manufacturing can be realized. Furthermore, since the first reflection / transmission layer 17 can be formed extremely thin (for example, 1 μm or less) by coating, the laser light L for each light emitting element 7 is transmitted through the first reflection / transmission layer 17. (Lateral deviation of the laser beam L caused by refraction) can be reduced to a negligible level. Thereby, the linearity of the optical path on the incident side with respect to the first optical surface 14a and the optical path on the output side with respect to the second optical surface 14b can be ensured with higher accuracy.

  Furthermore, the inclination angle of the first optical surface 14a is preferably set to 130 ° to 140 ° (more preferably 135 °) counterclockwise in FIG. 1 with the left end surface 4b as a reference (0 °). Further, the inclination angle of the second optical surface 14b is set to 40 ° to 50 ° (more preferably 45 °) counterclockwise in FIG. 1 with the left end surface 4b as a reference (0 °). However, the symmetry between the first optical surface 14a and the second optical surface 14b is maintained. Further, the total reflection surface 4d is formed in parallel to the second optical surface 14b. In this way, the laser light L for each light emitting element 7 incident on the total reflection surface 4d is totally reflected toward the concave portion 14 side, and the laser light L incident on the first optical surface 14a is second reflected. It is possible to design without any difficulty in separating the light into the lens surface 12 side and the third lens surface 13 side. In particular, when the inclination angle of the first optical surface 14a is 135 °, and the inclination angles of the second optical surface 14b and the total reflection surface 4d are 45 °, the design and dimensional accuracy of each surface 14a, 14b, 4d. Measurement is further simplified.

  Furthermore, the lower end surface 4a and the left end surface 4b are formed perpendicular to each other, and the optical axis OA (1) on the first lens surface 11 and the optical axis OA (3) on the third lens surface 13 are defined. The optical axis OA (2) on the second lens surface 12 may be formed perpendicular to the left end surface 4b. In this way, the dimensional accuracy required for the lens array 2 in order to secure the optical path connecting the light emitting element 7 and the first light receiving element 8 and the optical path connecting the light emitting element 7 and the end face 5a of the optical fiber 5 is improved. It can be mitigated and further ease of manufacture can be realized. That is, for example, when the optical axis OA (3) on the third lens surface 13 is configured to have an acute inclination with respect to the optical axis OA (1) on the first lens surface 11, for example. 1 may cause the monitor light M emitted from the third lens surface 13 not to be coupled to the first light receiving element 8 due to a slight dimensional error in the vertical direction in FIG. On the other hand, if the optical axis OA (1) on the first lens surface 11 and the optical axis OA (3) on the third lens surface 13 are formed in parallel to each other as in the present embodiment, Even if a slight dimensional error in the vertical direction in FIG. 1 occurs in the lens array 2, the monitor light M emitted from the third lens surface 13 only has a beam diameter larger or smaller than the design value. Each first light receiving element 8 receives light appropriately. If the optical axis OA (2) on the second lens surface 12 is configured to have an angle other than a right angle with respect to the optical axis OA (1) on the first lens surface 11, The laser light L emitted from the second lens surface 12 may not be coupled to the end surface of the optical fiber 5 due to a slight dimensional error in the lateral direction in FIG. On the other hand, if the optical axis OA (1) on the first lens surface 11 and the optical axis OA (2) on the second lens surface 12 are formed perpendicular to each other as in this embodiment, Even if a slight dimensional error in the lateral direction in FIG. 1 occurs in the lens array 2, the laser beam L emitted from the second lens surface 12 only has a slightly larger or smaller beam diameter than the design value. Thus, it is properly coupled to the end face of the optical fiber 5.

  In addition to the above configuration, in the present embodiment, as shown in FIGS. 1 and 2, when the recess 14 is viewed from the surface normal direction of the upper end surface 4 c (upward in FIG. 1), the recess 14 The bottom surface (lower end surface in FIG. 1) 14e and all the side surfaces 14a to 14d are formed in a shape that falls within the range indicated by the outer shape of the opening 14f in the recess 14. In other words, the recess 14 is formed so that the projection surface in the surface normal direction of the upper end surface 4c for each of the bottom surface 14e and all the side surfaces 14a to 14d is within the range indicated by the outer shape of the opening 14f. Has been. As shown in FIG. 2, the opening 14f is formed in a rectangular shape elongated in the vertical direction in FIG. 2, and is surrounded by the upper end surface 4c on all sides. Further, the side surfaces 14c and d other than the first optical surface 14a and the second optical surface 14b are formed perpendicular to the upper end surface 4c. According to such a configuration, the concave portion 14 can be formed in a shape that can ensure releasability from the mold, so that efficient production of the lens array 2 using the mold is realized. Can do.

  Note that the third lens surface 13 and the first light receiving elements 8 corresponding to the third lens surfaces 13 do not necessarily have to be provided in the same number as the light emitting elements 7, and at least one set may be provided. In this case, in the first reflection / transmission layer 17, the laser light having the corresponding third lens surface 13 out of the laser light L for each light emitting element 7 incident on each first lens surface 11. Only L is reflected as the monitor light M, and the other laser light L is reflected but not used as the monitor light M.

  Further, the first optical plate 15 and the second optical plate 16 may be formed of an inexpensive material such as BK7 or white plate glass.

  Furthermore, the refractive index difference of the first optical plate 15 with respect to the lens array body 4 is such that the incident angle of the laser light L for each light emitting element 7 with respect to the first optical plate 15 does not exceed the critical angle. Any difference is sufficient. For example, as described above, assuming that the inclination angle of the first optical surface 14a (also the inclination angle of the first optical plate 15) is 135 ° and the refractive index of the lens array body 4 is 1.64. The refractive index of the first optical plate 15 may be 1.16 or more.

(Modification)
Next, a modified example of the present embodiment will be described with reference to FIGS. 6 to 10 with a focus on differences from the configuration of FIG.

  Note that portions that are the same as or similar to the configuration in FIG. 1 will be described using the same reference numerals.

  FIG. 6 is a schematic configuration diagram showing an outline of the optical module 21 in the present modification example together with a longitudinal sectional view of the lens array 22 in the present modification example. FIG. 7 is a plan view of the lens array 22 shown in FIG. 8 is a left side view of FIG. FIG. 9 is a right side view of FIG. FIG. 10 is a bottom view of FIG.

  In the present modification, as one of the differences from the configuration of FIG. 1, when the photoelectric conversion device 3 and the optical fiber 5 are fixed to the lens array 22, the positioning of the photoelectric conversion device 3 and the optical fiber 5 is mechanical. Means are taken to do it automatically.

  That is, as shown in FIGS. 6 and 10, in the present modification, the first lens surface 11 and the second lens surface 12 are first counterbore portions that are recessed in the lower end surface 4 a of the lens array body 4. 23 is formed on the bottom surface 23a (the first surface in this modification). The bottom face 23a of the first counterbore part 23 is formed in parallel to the lower end face 4a. As shown in FIG. 10, the width of the first counterbore 23 in the vertical direction in FIG. 10 (hereinafter referred to as the lens alignment direction) is slightly smaller than the outermost lens surfaces 11 and 13 in the lens alignment direction. The width is formed so as to reach the outside. In this modification, the width of the lens array body 4 in the lens alignment direction is formed larger than the width of the first counterbore 23 in the lens alignment direction, and accordingly, as shown in FIG. In addition, the lower end surface 4 a extends to both outer sides in the lens alignment direction with respect to the first counterbore portion 23. As shown in FIG. 10, each extending portion extending from the first counterbore portion 23 in the lower end surface 4 a toward both outer sides in the lens alignment direction has a positioning structure of the photoelectric conversion device 3 as a positioning structure. A total of four planar circular fitting hole portions 24 are formed with two counterbore portions 23 interposed therebetween. In these fitting holes 24, fitting pins (not shown) that penetrate the semiconductor substrate 6 are fitted in a state where the semiconductor substrate 6 is in contact with the extended portion of the lower end surface 4 a. Accordingly, the photoelectric conversion element device 3 can be mechanically positioned when the photoelectric conversion element device 3 is fixed to the lens array 22.

  Further, as shown in FIGS. 6 and 8, in the present modification, the second lens surface 12 is a bottom surface 26a of the second counterbore portion 26 provided in the left end surface 4b of the lens array 4 (this embodiment). 2nd surface). The bottom face 26a of the second counterbore part 26 is formed in parallel to the left end face 4b. As shown in FIG. 8, the width of the second counterbore portion 26 in the lens alignment direction is formed to be slightly outside the lens surface 12 formed on the outermost side in the lens alignment direction. As shown in FIG. 8, in this modification, the left end surface 4 b extends to both outer sides in the lens alignment direction with respect to the second counterbore portion 26, and these extended portions have As shown in FIG. 8, the optical fiber 5 has a positioning structure in which a total of two fitting pins 27 are provided so as to sandwich the second counterbore portion 26 therebetween. These fitting pins 27 are adapted to be fitted into fitting holes (not shown) formed in the connector 10 in a state where the connector 10 is in contact with each extending portion of the left end surface 4b. As a result, the optical fiber 5 can be mechanically positioned when the optical fiber 5 is fixed to the lens array 22.

  Even in the configuration of this modification, it is possible to achieve the same excellent effects as in FIG. In this modification, the photoelectric conversion element device 3 and the optical fiber 5 can be easily positioned with respect to the lens array 22 by using the positioning structures 24 and 27. Can be easily fixed to the lens array 22.

  Further, as shown in FIG. 6, in this modification, the side surface of the recess 14 is formed to extend vertically upward from the upper end portions of the first and second optical surfaces 14a and 14b.

  Instead of the fitting hole 24 described above, a through hole having the same diameter as the fitting hole 24 that penetrates the lens array body 4 may be formed. The positioning structure of the optical fiber 5 may be a fitting hole or a through hole on the lens array body 4 side and a fitting pin on the optical fiber 5 side. Similarly, in the positioning structure of the photoelectric conversion element device 3, the lens array body 4 side may be a fitting pin, and the photoelectric conversion element device 3 side may be a fitting hole or a through hole. Note that the positioning of the optical fiber 5 and the photoelectric conversion device 3 is not limited to mechanical positioning, for example, by an optical method by optically recognizing a mark formed on the lens array body 4. You may make it perform.

  As a modification other than such a modification, although not shown, the reflective / transmissive layer 17 may be formed on the surface of the first optical plate 15 on the filler 18 side. In this case, the first optical plate 15 is disposed in close contact with the first optical surface 14a, and the reflection / transmission layer 17 is disposed in the vicinity of the first optical surface 14a. become.

  In the configuration of FIG. 1, an antireflection film (AR coating) may be formed on the surface of the first optical plate 15 on the filler 18 side.

(Second Embodiment)
Next, a lens array according to a second embodiment of the present invention and an optical module including the lens array will be described with reference to FIG. 11 with a focus on differences from the first embodiment.

  Note that the same or similar parts as those in the first embodiment will be described using the same reference numerals.

  FIG. 11 is a schematic configuration diagram showing an outline of the optical module 30 in the present embodiment together with a longitudinal sectional view of the lens array 31 in the present embodiment.

  As shown in FIG. 11, the difference between the configuration of the present embodiment and the first embodiment is that the first optical plate 15 is interposed through the first adhesive sheet 32 of a predetermined refractive index having a uniform thickness. The second optical plate 16 is attached to the first optical surface 14a, and the second optical plate 16 is connected to the second adhesive sheet 33 having the same refractive index as that of the first adhesive sheet 32 having a uniform thickness. It exists in being affixed on the optical surface 14b. In the present embodiment, the first reflection / transmission layer 17 is positioned between the first optical plate 15 and the first adhesive sheet 32 and in the vicinity of the first optical surface 14a. Has been placed. Moreover, in this embodiment, the 1st adhesive sheet 32 and the 2nd adhesive sheet 33 are formed so that air conversion length may become equal mutually.

  According to such a configuration, the first optical plate 15 and the second optical plate 16 can be more stably fixed to the lens array body 4. In addition, since both the adhesive sheets 32 and 33 are formed to have the same refractive index, the influence of refraction when the laser light L for each light emitting element 7 enters the first adhesive sheet 32 is affected by each light emitting element. It can be eliminated by refraction when the laser beam L for every seven is incident on the second adhesive sheet 33. Therefore, as in the first embodiment, the optical path between the total reflection surface 4d of the laser light L for each light emitting element 7 and the first optical surface 14a and the optical path on the emission side with respect to the second optical surface 14b Linearity can be ensured.

  Further, preferably, the first and second adhesive sheets 32 and 33 are configured such that the difference in refractive index from the lens array body 4 is 0.35 or less (more preferably 0). In this way, since the Fresnel reflection of the laser light L for each light emitting element 7 at the interface between the lens array main body 4 and each adhesive sheet 32, 33 can be suppressed, generation of stray light and reduction in coupling efficiency are suppressed. can do.

  In addition, as each adhesive sheet 32 and 33, the thin index (for example, 20 micrometers) refractive index matching film etc. which have adhesiveness like the Yodogawa Paper Mill's Fitwell (trademark) can be used, for example.

  Moreover, the modification applied to 1st Embodiment is applicable as it is also in this embodiment.

(Third embodiment)
Next, a lens array according to a third embodiment of the present invention and an optical module including the lens array will be described with reference to FIGS. 12 and 13 with a focus on differences from the first embodiment.

  Note that the same or similar parts as those in the first embodiment will be described using the same reference numerals.

  FIG. 12 is a schematic configuration diagram showing an outline of the optical module 35 in the present embodiment together with a longitudinal sectional view of the lens array 36 in the present embodiment. FIG. 13 is a bottom view of the lens array 36 shown in FIG.

  As shown in FIGS. 12 and 13, the difference between the configuration of the present embodiment and the first embodiment is that the configuration of the present embodiment can be applied not only to transmission of optical signals but also to reception. is there.

  That is, in the present embodiment, laser beams having the same wavelength are emitted from the end face 5 a of each optical fiber 5 toward the lens array 36, and the laser light emitted from each of these optical fibers 5. Is a laser beam having a wavelength different from that of the laser beam L for each light emitting element 7. As a more specific means, a plurality of light emitting elements (not shown) of the same number as the optical fiber 5 are arranged on the end face opposite to the end face 5a in the optical fiber 5, and the light emitted from these light emitting elements corresponds. What is necessary is just to make it enter into the optical fiber 5, respectively.

  The laser light emitted from each optical fiber 5 in this way is input to each second lens surface 12 corresponding to each optical fiber.

  As shown in FIG. 12, in the present embodiment, the photoelectric conversion device 3 is a surface facing the lens array 36 in the semiconductor substrate 6, at a position in the vicinity of the left part of FIG. 12 with respect to the first light receiving element 8. A plurality of second light receiving elements 37 that receive the laser light emitted from each optical fiber 5 are provided. The plurality of second light receiving elements 37 are formed at the same number and the same pitch as the second lens surfaces 12 along the same direction as the alignment direction of the second lens surfaces 12. Each second light receiving element 37 may be a photodetector.

  Further, as shown in FIGS. 12 and 13, the laser light emitted from each optical fiber 5 incident from the inner side of the lens array body 4 is placed at a position facing each second light receiving element 37 on the lower end surface 4a. A plurality of fourth lens surfaces 38 that are emitted toward the second light receiving elements 37 are formed. The plurality of fourth lens surfaces 38 are formed at the same number and the same pitch as the second lens surfaces 12 along the same direction as the alignment direction of the second lens surfaces 12 (the vertical direction in FIG. 13). .

  Furthermore, as shown in FIG. 12, a second reflection / transmission layer 40 is disposed between the second optical surface 14 b and the second optical plate 16. The second reflection / transmission layer 40 is in close contact with the second optical surface 14b in a state of being formed entirely on the second optical plate 16 (the lower surface in FIG. 12).

  Here, the laser light emitted from each optical fiber 5 incident on each second lens surface 12 is incident on the second reflection / transmission layer 40. The second reflection / transmission layer 40 reflects the incident laser light to each fourth lens surface 38 side with a predetermined reflectance and transmits the laser light with a predetermined transmittance.

  According to such a configuration, the laser light emitted from each optical fiber 5 passes through each second lens surface 12, second reflection / transmission layer 40, and each fourth lens surface 38, so that the second Since it can couple | bond with the light receiving element 37, it can respond | correspond effectively to bidirectional | two-way optical communication.

  Note that the second reflective / transmissive layer 40 may be formed by the same material and method as the first reflective / transmissive layer 17.

  Further, from the viewpoint of ease of design, it is desirable that the optical axis OA (4) on the fourth lens surface 38 is perpendicular to the lower end surface 4a.

(Modification)
Next, a modification of the present embodiment will be described with reference to FIG. 14 with a focus on differences from the configuration of FIG.

  As shown in FIG. 14, the difference between the configuration of this modification and the configuration of FIG. 12 is that, in this modification, the first optical plate 15 is replaced with the first adhesive sheet 32 as in the second embodiment. The second optical plate 16 is attached to the second optical surface 14b via the second adhesive sheet 33, and the second optical plate 16 is attached to the first optical surface 14a.

  In addition, the modification applied to the first embodiment can also be applied as it is in the present embodiment.

(Fourth embodiment)
Next, a fourth embodiment of the lens array and the optical module including the lens array according to the present invention will be described with reference to FIG. 15 focusing on differences from the first embodiment.

  Note that the same or similar parts as those in the first embodiment will be described using the same reference numerals.

  FIG. 15 is a schematic configuration diagram showing an outline of the optical module 42 in the present embodiment together with a longitudinal sectional view of the lens array 43 in the present embodiment.

  As shown in FIG. 15, the difference between the configuration of the present embodiment and the first embodiment is that, in the present embodiment, the first reflective / transmissive layer 17 is directly formed on the first optical surface 14a by coating or the like. In addition, the first optical plate 15 and the second optical plate 16 are not provided.

  According to such a configuration, the laser light L for each light emitting element 7 after passing through the first reflection / transmission layer 17 travels straight toward the second lens surface 12 without being refracted. . Even in such a configuration, linearity between the light path on the incident side with respect to the first optical surface 14a and the light path on the output side with respect to the second optical surface 14b can be ensured as in the first embodiment.

  According to the present embodiment, it is necessary to form the first reflection / transmission layer 17 directly on the lens array body 4, but the number of parts can be reduced.

  Note that the modification applied to the first embodiment can also be applied to this embodiment as it is.

(Fifth embodiment)
Next, a fifth embodiment of the lens array and the optical module including the same according to the present invention will be described with reference to FIG. 16 focusing on differences from the third embodiment.

  Note that the same or similar parts as those in the third embodiment will be described using the same reference numerals.

  FIG. 16 is a schematic configuration diagram showing an outline of the optical module 45 in the present embodiment together with a longitudinal sectional view of the lens array 46 in the present embodiment.

  As shown in FIG. 16, the difference between the configuration of the present embodiment and the first embodiment is that in the present embodiment, the first reflective / transmissive layer 17 is formed directly on the first optical surface 14a, and The second reflection / transmission layer 40 is formed directly on the second optical surface 14b, and further does not have the first optical plate 15 and the second optical plate 16.

  Note that the modification applied to the first embodiment can also be applied to this embodiment as it is.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the characteristics of the present invention.

  For example, the lens array body 4 may be formed of a light-transmitting material (for example, glass) other than the resin material.

  Further, the present invention may be applied to an optical transmission body other than the optical fiber 5 such as a sheet-like optical waveguide.

DESCRIPTION OF SYMBOLS 1 Optical module 2 Lens array 3 Photoelectric conversion apparatus 4 Lens array main body 5 Optical fiber 5a End surface 7 Light emitting element 8 1st light receiving element 11 1st lens surface 12 2nd lens surface 13 3rd lens surface 14 Recessed part 14a 1st 1 optical surface 14b second optical surface 17 first reflective / transmissive layer 18 filler

Claims (8)

A photoelectric conversion apparatus in which a plurality of light emitting elements are aligned and at least one first light receiving element for receiving monitor light for monitoring light emitted from at least one of the plurality of light emitting elements is formed; A lens array disposed between the optical transmission body and capable of optically coupling the plurality of light emitting elements and an end face of the optical transmission body,
A first surface of the lens array body facing the photoelectric conversion device is formed so as to be aligned in a predetermined alignment direction corresponding to the plurality of light emitting elements, and light emitted from each of the plurality of light emitting elements is incident on the first surface. A plurality of first lens surfaces to be
The lens array body is formed so as to be aligned with the second surface that faces the end surface of the optical transmission body and is perpendicular to the first surface along the alignment direction of the first lens surface. A plurality of second lens surfaces that respectively emit light for each of the plurality of light emitting elements respectively incident on the plurality of first lens surfaces toward an end surface of the optical transmission body;
At least one third lens surface formed on the first surface of the lens array body and emitting the monitor light incident from the inside of the lens array body toward the first light receiving element;
A recess formed to be recessed in a third surface facing the first surface of the lens array body so as to be positioned on an optical path connecting the first lens surface and the second lens surface;
The plurality of first lenses are formed so as to form a part of the inner surface of the recess and to have an inclination angle with respect to the second surface that is away from the second surface as the distance from the first surface increases. A first optical surface on which light for each of the plurality of light emitting elements incident on the surface is incident from an incident direction perpendicular to the second surface;
The concave portion is a part of the inner surface and forms a portion facing the first optical surface, and is formed to have a predetermined inclination angle with respect to the second surface. A second optical surface on which light for each of the plurality of light emitting elements that has traveled toward the second lens surface after being incident is incident;
The plurality of light emitting elements arranged on the optical path of the light for each of the plurality of light emitting elements between the first lens surface and the first optical surface in the lens array main body and incident on the first lens surface A total reflection surface that totally reflects light for each element toward the first optical surface;
The light for each of the plurality of light emitting elements, which is disposed on or near the first optical surface and is incident on the first optical surface, is reflected to the third lens surface side with a predetermined reflectance and is predetermined. A first reflection / transmission layer that transmits to the second optical surface side at a transmittance of at least one of the plurality of light emitting elements and reflects as at least one of the monitor light as the monitor light;
The lens array body and the filler having the same refractive index, which are filled with no gap by moving downward into the upwardly open space formed by the recess,
When the tilt angle of the first optical surface is θ [°], the tilt angle of the second optical surface is expressed as 180−θ [°],
The optical path between the total reflection surface on the incident side of the light for each of the plurality of light emitting elements with respect to the first optical surface and the first optical surface, and the second optical of the light for each of the plurality of light emitting elements. A lens array, wherein the light path on the emission side with respect to the surface is positioned on the same straight line. The optical transmission body is formed to emit light toward the lens array body,
The second lens surface is formed so that light emitted from the optical transmission body is incident thereon,
The photoelectric conversion device includes a second light receiving element that receives light emitted from the optical transmission body,
First light that is emitted from the optical transmission body that is incident from the inside of the lens array body at a position facing the second light receiving element on the first surface is emitted toward the second light receiving element. 4 lens surfaces are formed,
On the second optical surface or in the vicinity thereof, the light emitted from the optical transmission body incident on the second lens surface is reflected to the fourth lens surface side with a predetermined reflectance and is The lens array according to claim 1, wherein a second reflection / transmission layer that transmits light with transmittance is formed. The first reflective / transmissive layer is formed on a first optical plate having a predetermined refractive index parallel to the first optical surface;
A second optical plate having the same refractive index as that of the first optical plate parallel to the second optical surface is disposed on or in the vicinity of the second optical surface,
The second optical plate is formed in the inside of the filler of the light for each of the plurality of light emitting elements generated by being refracted when the light for each of the plurality of light emitting elements is incident on the first optical plate. A deviation in the direction perpendicular to the optical path length direction between the optical path and a predetermined range of optical paths on the incident side with respect to the first optical surface is eliminated, and the optical path on the output side with respect to the second optical surface is the first optical surface. 2. The lens array according to claim 1, wherein the optical path is adjusted so as to be positioned on the same straight line as a predetermined range of the optical path on the incident side with respect to the surface. The first reflective / transmissive layer is formed on a first optical plate having a predetermined refractive index parallel to the first optical surface;
The second reflection / transmission layer is formed on a second optical plate having the same refractive index as that of the first optical plate parallel to the second optical surface,
The second optical plate is formed in the inside of the filler of the light for each of the plurality of light emitting elements generated by being refracted when the light for each of the plurality of light emitting elements is incident on the first optical plate. A deviation in the direction perpendicular to the optical path length direction between the optical path and a predetermined range of optical paths on the incident side with respect to the first optical surface is eliminated, and the optical path on the output side with respect to the second optical surface is the first optical surface. 3. The lens array according to claim 2, wherein the optical path is adjusted so as to be positioned on the same straight line as the optical path of a predetermined range on the incident side with respect to the surface. The filler is made of a translucent adhesive,
The lens array according to claim 3 or 4, wherein the first optical plate and the second optical plate are bonded to the lens array body by the filler. The first optical plate is attached to the first optical surface via a first adhesive sheet having a predetermined refractive index,
The second optical plate is attached to the second optical surface via a second adhesive sheet having the same refractive index as that of the first adhesive sheet. The lens array according to any one of the above. The inclination angle of the first optical surface is 135 [°],
The inclination angle of the second optical surface is 45 [°],
The total reflection surface is formed in parallel with the second optical surface;
An optical axis on each lens surface formed on the first surface is formed perpendicular to the first surface;
The lens array according to any one of claims 1 to 6, wherein an optical axis on the second lens surface is formed perpendicular to the second surface.   An optical module comprising the lens array according to any one of claims 1 to 7 and the photoelectric conversion device according to claim 1 or 2.

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