JP2011248312A - Optical element and optical device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element that is used for an optical coupling between an optical fiber and a light receiving/emitting element in an optical device using an optical fiber, ensuring a low profile of the optical device.SOLUTION: Optical elements 20a, 20b comprise a first light incident/emitting face 21 facing light receiving/emitting elements 11, 12, a second light incident/emitting face 22 facing an optical fiber 10, and a light reflection face 23. The light reflection face 23 reflects the light incident from one of the first and second light incident/emitting faces 21, 22 to the other of the first and second light incident/emitting faces 21, 22. The second light incident/emitting face 22 has a lens surface portion 22a having a positive optical power.

Description

  The present invention relates to an optical element and an optical device including the same. In particular, the present invention relates to an optical element used for optical coupling between an optical fiber and a light receiving and emitting element in an optical apparatus using an optical fiber, and an optical apparatus including the same.

  In recent years, optical devices using optical fibers have attracted a great deal of attention as devices capable of realizing high-speed data transfer. In this optical device, light corresponding to the input data is emitted from the light emitting element. The emitted light propagates through the optical fiber, is guided to the light receiving element, and is converted into an electric signal again in the light receiving element. In this optical apparatus, it is necessary to optically couple the light receiving element or the light emitting element and the optical fiber. The coupling between the light emitting / receiving element and the optical fiber is performed by an optical element called an optical interconnector.

  Incidentally, in general, the optical axis of the light emitting / receiving element mounted on the circuit board is parallel to the normal direction of the circuit board. For this reason, for example, when optical coupling between an optical fiber and a light receiving and emitting element is performed using a condensing lens, the end of the optical fiber is provided perpendicular to the circuit board, and the optical fiber and the optical fiber are received and received. It is necessary to dispose a condensing lens between the light emitting element. Further, the optical fiber cannot be bent with a high curvature. Therefore, there is a problem that the height of the optical device becomes large and it is difficult to reduce the height of the optical device.

  On the other hand, in the optical device described in Patent Document 1 below, a low profile is achieved by using a refractive optical system and arranging an optical fiber parallel to the circuit board. Specifically, as shown in FIG. 9, the optical device 200 described in Patent Document 1 includes a connector 201. The connector 201 has a connector body 202 made of a transparent resin and formed integrally. The connector body 202 has a convex lens-shaped light receiving surface 202 a that receives light from the optical element 204 provided on the circuit board 203. Further, the connector main body 202 is formed with an optical fiber bottomed hole 202 c in which the tip of the optical fiber 205 is inserted and fixed in parallel with the circuit board 203. Further, the connector main body 202 is formed with a reflection surface 202b for guiding the light from the optical element 204 to the tip of the optical fiber 205 inserted into the optical fiber bottomed hole 202c. A reflective film (not shown) is formed on the reflective surface 202b.

JP 2007-121973 A

  Since the optical device 200 employs a refractive optical system, the optical fiber 205 can be disposed in parallel with the circuit board. Therefore, the height of the optical device 200 can be reduced. However, in the optical device 200, the connector main body 202 is made of resin, and the light receiving surface 202a is formed in a convex lens shape. Unlike FIG. 9, actually, the light receiving surface that receives light from the optical element 204 is received. The distance between 202a and the optical element 204 becomes long, and there is a problem that it is difficult to sufficiently reduce the height.

  The present invention has been made in view of such points, and an object thereof is an optical element used for optical coupling between an optical fiber and a light emitting / receiving element in an optical device using an optical fiber, An object of the present invention is to provide an optical element that can be reduced in height.

  The first optical element according to the present invention is an optical device including a light emitting / receiving element and an optical fiber having an optical axis at a tip portion perpendicular to the optical axis of the light receiving / emitting element. The present invention relates to an optical element made of glass used for bonding. The first optical element according to the present invention includes a first light input / output surface, a second light input / output surface, and a light reflecting surface. The first light entrance / exit surface faces the light emitting / receiving element. The second light entrance / exit surface faces the optical fiber. The light reflecting surface reflects light incident from one of the first and second light input / output surfaces to the other side of the first and second light input / output surfaces. The second light entrance / exit surface has a lens surface portion having a positive optical power.

  In the first optical element according to the present invention, a lens surface portion having positive optical power is formed on the second light entrance / exit surface on the optical fiber side. For this reason, it is possible to reduce the beam diameter on the first light entrance / exit surface on the light emitting / receiving element side. Furthermore, since the first optical element according to the present invention is made of glass, the refractive index of the optical element can be increased. Accordingly, the distance between the first light entrance / exit surface and the light emitting / receiving element can be shortened. Therefore, by using the first optical element according to the present invention, the height of the optical device can be reduced.

  In the present invention, the “light emitting / receiving element” is a general term for a light receiving element and a light emitting element. That is, the “light emitting / receiving element” includes “light receiving element” and “light emitting element”.

  In the present invention, “optical coupling between the optical fiber and the light receiving / emitting element” means that the light emitted from the optical fiber is focused on the light receiving surface of the light receiving element, or the light from the light emitting element is To focus on the end face.

  In the present invention, “light entrance / exit surface” is a general term for “light entrance surface” and “light exit surface”. That is, the “light entrance / exit surface” includes a “light entrance surface” and a “light exit surface”.

  The 2nd optical element which concerns on this invention is related with the optical element made from glass used for the optical coupling | bonding of an optical fiber and a light emitting / receiving element. The second optical element according to the present invention has first and second light entrance / exit surfaces and a light reflection surface. The light reflecting surface reflects light incident from one of the first and second light input / output surfaces to the other side of the first and second light input / output surfaces. The second light entrance / exit surface has a lens surface portion having a positive optical power.

  By disposing the second optical element according to the present invention so that the second light incident / exit surface faces the optical fiber, the first optical element on the light emitting / receiving element side is the same as the first optical element according to the present invention. The light beam diameter on the light entrance / exit surface can be reduced. In addition, since the second optical element according to the present invention is also made of glass, the refractive index of the optical element can be increased. Accordingly, the distance between the first light entrance / exit surface and the light emitting / receiving element can be shortened. Therefore, the height of the optical device can be reduced by using the second optical element according to the present invention.

  In the first or second optical element according to the present invention, the lens surface portion is preferably formed in a shape such that light incident from the lens surface portion is focused on the first light entrance / exit surface. In this case, the light emitting / receiving element can be disposed immediately above the first light entrance / exit surface of the optical element. In other words, the clearance between the first light entrance / exit surface and the light emitting / receiving element can be made zero. Therefore, by using the optical element having this configuration, the height of the optical device can be further reduced.

  In the first or second optical element according to the present invention, each of the first and second light entrance / exit surfaces preferably has a lens surface portion having a positive optical power. In this case, the distance between the first light input / output surface portion and the light emitting / receiving element can be further shortened. Therefore, by using the optical element having this configuration, the height of the optical device can be further reduced.

  It is preferable that the refractive index (nd) with respect to each d line of the first and second optical elements according to the present invention is 1.75 or more. In this case, light can be largely refracted at each of the first and second light entrance / exit surfaces. Therefore, the distance between the first light entrance / exit surface and the light emitting / receiving element can be further shortened.

  The “d line” is a light beam having a wavelength of 588 nm.

  In the first or second optical element according to the present invention, it is preferable that a plurality of lens surface portions are formed in an array. In this case, a plurality of optical fibers can be optically coupled to the light emitting / receiving element with one optical element.

  In the first or second optical element according to the present invention, the optical element preferably further includes a reflection suppressing film formed on each of the first and second light entrance / exit surfaces. In this case, the light reflectivity at the first and second light incident surfaces can be reduced. Therefore, by using the first or second optical element according to the present invention, the light propagation loss in the optical device can be reduced.

  In the first or second optical element according to the present invention, the optical element is preferably formed by a mold press. In that case, the optical element can be manufactured at low cost. Moreover, since the ridgeline part and corner | angular part of an optical element become R chamfering shape, it becomes difficult to produce a crack and a chip | tip in a ridgeline part or a corner | angular part.

  In the first or second optical element according to the present invention, the optical element has first and second light entry / exit surfaces and a light reflection surface as side surfaces, and the second light entry / exit surface and the light reflection surface It is preferable that the corner | angular part comprised is substantially triangular prism shape formed in the chamfering shape. In this case, since the optical element can be reduced in height and weight, by using this optical element, the optical device can be further reduced in height and weight. In addition, when the optical element is fixed to the folder, the surface formed at the corner formed by the second light entrance / exit surface and the light reflecting surface is used as a contact surface with respect to the folder, so that the optical element and the folder And positioning with ease.

  In the first or second optical element according to the present invention, it is more preferable that a corner portion constituted by the first light entrance / exit surface and the light reflection surface is formed in a chamfered shape. In this case, since the optical element can be further reduced in size and weight, the optical device can be further reduced in size and weight by using this optical element.

  In the first or second optical element according to the present invention, irregularities are formed in a portion other than the portion located on at least one of the first and second light entry / exit surfaces and the light reflection surface. Is preferred. In this configuration, when the first and second light entrance / exit surfaces and the light reflection surface are bonded to the folder, the adhesive is applied to a portion other than the portion located on the optical path. By this, it can suppress that an adhesive agent flows in into the part located on an optical path. In addition, the optical element and the folder can be positioned by forming, in the folder, irregularities having a shape corresponding to the irregularities formed on at least one of the first and second light entrance / exit surfaces and the light reflecting surface. It becomes easy.

  The optical device according to the present invention includes a light emitting / receiving element, an optical fiber, and an optical element made of glass. The optical axis of the tip of the optical fiber is perpendicular to the optical axis of the light emitting / receiving element. The optical element optically couples the light emitting / receiving element and the optical fiber. The optical element includes a first light entrance / exit surface, a second light entrance / exit surface, and a light reflection surface. The first light entrance / exit surface faces the light emitting / receiving element. The second light entrance / exit surface faces the optical fiber. The light reflecting surface reflects light incident from one of the first and second light input / output surfaces to the other side of the first and second light input / output surfaces. The second light entrance / exit surface has a lens surface portion having a positive optical power.

  That is, the optical device according to the present invention includes the first or second optical element according to the present invention. For this reason, in the optical device according to the present invention, the height dimension can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, it is an optical element used for the optical coupling | bonding of an optical fiber and a light emitting / receiving element in the optical apparatus using an optical fiber, Comprising: The optical element which can make an optical apparatus low-profile can be provided.

It is a schematic diagram of the optical apparatus which concerns on one Embodiment of this invention. 1 is a schematic perspective view of an optical element according to an embodiment of the present invention. It is a partial schematic diagram of the optical apparatus according to the first comparative example. It is a schematic diagram of a part of an optical device according to a second comparative example. It is a partial schematic diagram of the optical apparatus which concerns on a 3rd comparative example. It is a partial schematic diagram of the optical apparatus which concerns on a 4th comparative example. It is a schematic diagram of a part of the optical device according to the first modification. It is a schematic diagram of a part of an optical device according to a second modification. 1 is a schematic cross-sectional view of an optical device described in Patent Document 1. FIG. It is a schematic diagram of the optical apparatus which concerns on a 3rd modification. It is a schematic perspective view of the optical element in the 4th modification. FIG. 10 is a schematic exploded perspective view of a part of an optical device according to a fourth modification. It is a schematic-drawing side view of a part of optical device concerning the 4th modification. FIG. 14 is a schematic view taken along arrow XIV in FIG. 13.

  Hereinafter, preferred embodiments of the present invention will be described by taking the optical device shown in FIGS. However, the optical devices shown in FIGS. 1, 7, and 8 are merely examples. The optical device according to the present invention is not limited to the optical device shown in FIGS.

(First embodiment)
FIG. 1 is a schematic diagram of an optical device according to the first embodiment. FIG. 2 is a schematic perspective view of the optical element according to the first embodiment.

  The optical device 1 shown in FIG. 1 includes a light emitting element 11 and a light receiving element 12 provided on a circuit board 13, and an optical fiber 10. The light emitting element 11 is an element that emits light according to data input from a control unit (not shown). The light emitting element 11 can be configured by, for example, a surface emitting laser capable of emitting light in the vertical direction with respect to the circuit board 13.

  The light receiving element 12 receives the light emitted from the light emitting element 11 and transmitted through the optical fiber 10, and outputs an electrical signal corresponding to the received light. The light receiving element 12 can be configured by, for example, a pin type photodiode that has a low dark current and can respond at high speed.

  The light emitting element 11 and the light receiving element 12 are optically connected via the optical fiber 10. Specifically, one end portion 10a of the optical fiber 10 is optically coupled by a glass optical element 20a. On the other hand, the other end 10b of the optical fiber 10 is optically coupled by a glass optical element 20b.

  Each of the optical elements 20 a and 20 b has a function of refracting the optical axis and a function of focusing incident light on the optical fiber 10 or the light receiving element 12. Therefore, the light emitted from the light emitting element 11 is refracted, focused on the optical fiber 10 having the optical axis A3 perpendicular to the optical axis A1 of the light emitting element 11, and enters the optical fiber 10. The light emitted from the optical fiber 10 is refracted and focused on the light receiving surface 12a of the light receiving element 12 having the optical axis A2 perpendicular to the optical axis A3 of the optical fiber 10.

  The optical element 20a and the optical element 20b have substantially the same configuration. Therefore, here, the configuration of the optical elements 20a and 20b will be described with reference to FIGS.

  The optical elements 20a and 20b are formed in a substantially triangular prism shape. Specifically, the optical elements 20a and 20b are formed in a triangular prism shape whose end faces are right-angled isosceles triangles. However, in the present invention, the optical element is not necessarily formed in a triangular prism shape whose end face is a right-angled isosceles triangle. The shape of the optical element is such that the first and second light incident / exit surfaces and the light reflecting surface reflect light incident from one of the first and second light incident / exit surfaces on the light reflecting surface. As long as it is provided so as to exit from the other of the two light entrance / exit surfaces, there is no particular limitation. For example, the optical element may be formed in a triangular prism shape having a triangular end face whose apex angle is not a right angle, or may be formed in a polygonal shape.

  The corners and ridges of the optical elements 20a and 20b are preferably formed in an R chamfer shape. By doing so, it becomes difficult to produce a crack and a chip | tip in the corner | angular part and ridgeline part of optical element 20a, 20b. The optical elements 20a and 20b in which corners and ridges are formed in an R chamfered shape can be formed by, for example, a mold press.

  The optical elements 20 a and 20 b have a first light entrance / exit surface 21, a second light entrance / exit surface 22, and a light reflection surface 23. The first light entrance / exit surface 21 faces the light emitting element 11 or the light receiving element 12. The second light entrance / exit surface 22 faces the end surface of the optical fiber 10.

  As shown in FIG. 1, on the first and second light entrance / exit surfaces 21, 22, the reflection suppressing films 24, 25 (in FIG. 2, the drawing of the reflection suppressing films 24, 25 is omitted. .) Is formed. The reflection suppressing films 24 and 25 reduce the light reflectivity at the first and second light entrance / exit surfaces 21 and 22. The antireflection films 24 and 25 are composed of, for example, a dielectric laminated film in which a high refractive index layer having a relatively high refractive index and a low refractive index film having a relatively low refractive index are alternately laminated. be able to. The high refractive index layer can be formed of, for example, titanium oxide. The low refractive index film can be formed of silicon oxide or the like.

  In the present embodiment, among the first and second light input / output surfaces 21 and 22, the second light input / output surface 22 facing the optical fiber 10 has a plurality of lens surface portions 22a formed in an array. Yes. In the present embodiment, an example in which the plurality of lens surface portions 22a are arranged in a straight line will be described. However, in the present invention, the arrangement of the plurality of lens surface portions 22a is not limited to a straight line. In the present invention, the plurality of lens surface portions may be arranged in a matrix. Further, only one lens surface portion may be formed on the second light entrance / exit surface.

  The light reflecting surface 23 is formed in a planar shape. In the light reflecting surface 23, the light incident from one of the first and second light entering / exiting surfaces 21, 22 is reflected by the light reflecting surface 23 and is emitted from the other of the first and second light entering / exiting surfaces 21, 22. It is provided as follows. Specifically, in the present embodiment, the light reflecting surface 23 is configured such that the light incident from one of the first and second light entrance / exit surfaces 21 and 22 is totally reflected by the light reflecting surface 23 and thus the first and second light beams. It is provided so as to exit from the other of the entrance / exit surfaces 21 and 22. For this reason, it is not necessary to separately provide a light reflecting film on the light reflecting surface 23. Therefore, the optical elements 20a and 20b can be easily manufactured.

  Further, when the light reflecting film is provided, the light reflecting film may be deteriorated by the laser light from the light emitting element 11. In particular, when the light emitted from the light emitting element 11 is high-power laser light, the light reflecting film is likely to deteriorate. On the other hand, in this embodiment, since the light reflecting film is not formed on the light reflecting surface 23, it is possible to suppress a decrease in light reflectance on the light reflecting surface 23 due to the deterioration of the light reflecting film. .

  Specifically, in order to cause total reflection to the air (refractive index 1.0) on the light reflecting surfaces 23 of the optical elements 20a and 20b, the optical element 20a at the wavelength of light from the light emitting element 11 is used. 20b may be provided so as to satisfy sin θ ≧ 1 / n, where n is the refractive index of 20b and θ is the incident angle of light from the light emitting element 11.

  For example, when the refractive index of the optical elements 20a and 20b at the wavelength of light from the light emitting element 11 is 1.75, the light reflecting surface 23 may be provided so that θ is about 34.9 ° or more. When the refractive index of the optical elements 20a and 20b at the wavelength of light from the light emitting element 11 is 1.6, the light reflecting surface 23 may be provided so that θ is about 38.7 ° or more.

  Thus, the critical angle of total reflection on the light reflecting surface 23 decreases as the refractive index of the optical elements 20a and 20b at the wavelength of light from the light emitting element 11 increases. Therefore, by increasing the refractive index of the optical elements 20a and 20b at the wavelength of light from the light emitting element 11, the degree of freedom in designing the optical elements 20a and 20b is improved. Therefore, the refractive index of the optical elements 20a and 20b at the wavelength of light from the light emitting element 11 is preferably higher. The refractive index of the optical elements 20a and 20b at the wavelength of light from the light emitting element 11 is preferably 1.70 or more, and more preferably 1.75 or more. Normally, when the refractive index of the optical elements 20a and 20b with respect to the d-line is high, the refractive index of the optical elements 20a and 20b at the wavelength of light from the light emitting element 11 also increases. For this reason, it is preferable that the refractive index (nd) with respect to d line | wire of the optical elements 20a and 20b is 1.75 or more, and it is more preferable that it is 1.80 or more.

  In this embodiment, more specifically, the refractive index of the optical elements 20a and 20b with respect to the d-line is 1.806, the refractive index at a wavelength of 850 nm is 1.790, and the refractive index at a wavelength of 1050 nm is 1. The refractive index at 784, the wavelength 1310 nm is 1.779, the refractive index at the wavelength 1550 nm is 1.775, and the light reflecting surface 23 is provided so that the incident angle is 45 °. Each of the first and second light entrance / exit surfaces 21 and 22 is provided with an incident angle of 90 °.

  The lens surface portion 22a has a positive optical power. Specifically, in the present embodiment, the lens surface portion 22a is formed in a convex shape and is a refracting surface that refracts light. More specifically, in the present embodiment, the lens surface portion 22a is aspheric. Here, "aspherical surface" refers to a surface having a rotational symmetry axis among non-spherical surfaces.

  However, in the present invention, the lens surface portion is not particularly limited as long as it has a positive optical power. The lens surface portion may be, for example, a free curved surface that does not have a rotational symmetry axis. Further, the lens surface portion may be constituted by a Fresnel lens surface in which a plurality of lens surfaces are discontinuously arranged, or may be constituted by a diffraction surface that diffracts light.

  As in the present embodiment, when the lens surface portion is a refracting surface formed in a convex shape, the optical element can be easily manufactured. On the other hand, when the lens surface portion is constituted by a diffractive surface or a Fresnel lens surface, the height of the lens surface portion can be suppressed. It is also easy to achieve higher positive optical power.

  On the other hand, no lens surface portion is formed on the first light entrance / exit surface 21. In the present embodiment, the first light entrance / exit surface 21 is formed in a planar shape.

  Next, the operation of the optical device 1 will be described mainly with reference to FIG.

  When a signal is input to the light emitting element 11 from a control unit (not shown), the light emitting element 11 emits light corresponding to the input signal. Here, specifically, the light emitting element 11 emits radiated light.

  The light from the light emitting element 11 enters the optical element 20a from the first light incident / exit surface 21 (light incident surface) of the optical element 20a, is reflected by the light reflecting surface 23, and is then reflected by the second light incident / exit surface 22. Out of the optical element 20a from the lens surface portion 22a. Here, as described above, the light emitted from the light emitting element 11 is radiated light, and the first light entrance / exit surface 21 is formed in a planar shape. For this reason, the light propagating in the optical element 20a becomes divergent light. When the light is emitted from the optical element 20 a, the light is refracted by the lens surface portion 22 a having a positive optical power, becomes focused light, and is focused on the end surface of the optical fiber 10.

  The focused light propagates through the optical fiber 10 and is emitted from the end face of the end portion 10b as divergent light. The emitted light enters from the lens surface portion 22a of the second light entrance / exit surface 22 of the optical element 20b, is reflected by the light reflecting surface 23, and then exits from the first light entrance / exit surface 21. Here, in the present embodiment, the lens surface portion 22a has positive optical power. For this reason, the light incident on the optical element 20b becomes focused light. Then, the light is further refracted at the first light entrance / exit surface 21 formed in a planar shape, and is focused on the light receiving surface 12 a of the light receiving element 12.

  The light receiving element 12 outputs an electrical signal corresponding to the light received on the light receiving surface 12a. Through the above steps, an electrical signal corresponding to the signal input to the light emitting element 11 is output from the light receiving element 12.

  As described above, in the optical elements 20a and 20b of this embodiment, the light incident from one of the first and second light entrance / exit surfaces 21 and 22 is reflected by the light reflecting surface 23 and refracted. Therefore, by using the optical elements 20 a and 20 b, the optical fiber 10 can be arranged to be inclined with respect to the optical axes of the light emitting element 11 and the light receiving element 12. For example, the optical fiber 10 can be disposed perpendicular to the optical axes of the light emitting element 11 and the light receiving element 12. Further, in the optical elements 20a and 20b of the present embodiment, a lens surface portion 22a having a positive optical power is formed on the second light entrance / exit surface 22 on the optical fiber 10 side. For this reason, the beam diameter at the first light entrance / exit surface 21 on the light receiving element 12 or the light emitting element 11 side can be reduced. Furthermore, since the optical elements 20a and 20b are made of glass, the refractive index can be increased. Accordingly, the distance between the first light entrance / exit surface 21 and the light receiving element 12 or the light emitting element 11 can be shortened. Therefore, the height of the optical device 1 can be reduced.

  Hereinafter, this reason will be described in more detail.

  FIG. 3 is a schematic diagram of a part of the optical device according to the first comparative example. In the optical device shown in FIG. 3, the optical fiber 101 and the light receiving element 102 are optically coupled by a lens 103 having no reflecting surface. For this reason, it is necessary to arrange | position the edge part 101a of the optical fiber 101 so that an optical axis may correspond with the optical axis of the light receiving element 102. FIG. Therefore, the lens 103 and the end portion 101 a of the optical fiber 101 are arranged in the optical axis direction of the light receiving element 102. Therefore, it is difficult to reduce the height of the optical device.

  FIG. 4 is a schematic diagram of a part of the optical device according to the second comparative example. In the optical device shown in FIG. 4, a refractive optical system is configured by providing the reflecting member 104 on the lens 103. For this reason, in the optical device shown in FIG. 4, the optical axis of the end 101 a of the optical fiber 101 can be arranged perpendicular to the optical axis of the light receiving element 102 at a location different from the optical axis of the light receiving element 102. It is possible to reduce the height. However, it is necessary to arrange the light receiving element 102, the lens 103, and the reflecting member 104 in the optical axis direction of the light receiving element 102. For this reason, it is impossible to sufficiently reduce the height of the optical device.

  FIG. 5 is a schematic diagram of a part of the optical device according to the third comparative example. In the optical device shown in FIG. 5, a prism 106 is arranged instead of the lens 103 and the reflecting member 104. Of the light input / output surfaces 106a and 106b of the prism 106, a lens surface portion 106b1 having a positive optical power is provided on the light input / output surface 106b on the light receiving element 102 side. In this optical device, since only the prism 106 needs to be disposed in the optical axis direction of the light receiving element 102, the height of the optical device can be reduced.

  However, in the optical device shown in FIG. 5, the light input / output surface 106a on the optical fiber 101 side is formed in a flat shape. For this reason, the light incident on the prism 106 propagates in the prism 106 as divergent light. Therefore, the beam diameter increases as it propagates through the prism 106. Therefore, for example, as shown in FIG. 5, a part of the light incident from the light entrance / exit surface 106a may not be propagated to the light entrance / exit surface 106b. In order to ensure that the light incident from the light entrance / exit surface 106a propagates to the light entrance / exit surface 106b, the prism 106 needs to be enlarged. However, when the prism 106 is enlarged, the optical device is enlarged.

  Further, in order to ensure that the light incident from the light entrance / exit surface 106a propagates to the light entrance / exit surface 106b, the spot diameter of the light incident on the light entrance / exit surface 106a of the prism 106 is reduced as shown in FIG. It is also possible. However, even in this case, the light beam diameter at the light entrance / exit surface 106b, which is the light exit surface, increases. For this reason, the distance from the light entrance / exit surface 106b to a focus becomes long. Therefore, the height of the optical device cannot be sufficiently reduced.

  For example, if the optical power of the lens surface portion 106b1 is increased, the distance from the light entrance / exit surface 106b to the focal point can be shortened, but the lens surface portion 106b1 and the light receiving element 102 may interfere with each other in position. For example, when the lens surface portion 106b1 is formed of a refracting surface, since the curvature of the lens surface portion 106b1 is increased, it is difficult to manufacture an optical element. In particular, when an optical element is to be manufactured by a mold press, it is more difficult to manufacture the optical element.

  On the other hand, in this embodiment, as shown in FIG. 1, the lens surface portion 22a is formed on the second light entrance / exit surface 22 on the optical fiber 10 side. For this reason, the light beam diameter becomes smaller as it propagates through the optical element 20b. Therefore, the light beam diameter on the first light entrance / exit surface 21 on the light receiving element 12 side is reduced. In addition, since the light incident on the first light entrance / exit surface 21 is focused light, the focal length is further shortened by being refracted when the light is emitted from the optical element 20b. In particular, in the present embodiment, the optical element 20b is made of glass and has a high refractive index, and therefore has a very short focal length. Accordingly, the distance between the first light entrance / exit surface 21 of the optical element 20b and the light receiving surface 12a of the light receiving element 12 can be shortened. Similarly, on the light emitting element 11 side, the distance between the light emitting element 11 and the first light entrance / exit surface 21 of the optical element 20a can be shortened. Therefore, the height of the optical device 1 can be reduced.

  Furthermore, the number of components of the optical device 1 can be reduced by using the optical elements 20a and 20b having both a so-called prism function and a lens function as in this embodiment.

  In the optical elements 20a and 20b of the present embodiment, a plurality of lens surface portions 22a are formed in an array. For this reason, a plurality of optical fibers 10 can be optically coupled to the light receiving element 12 and the light emitting element 11 by one optical element 20a, 20b. Compared with the case where an optical element is provided for each optical fiber, the optical device can be miniaturized, and the alignment of the optical element is facilitated.

  Hereinafter, modifications of the embodiment will be described. In the following description, members having substantially the same functions as those in the above embodiment are referred to by the same reference numerals, and description thereof is omitted.

(First modification)
FIG. 7 is a schematic diagram of a part of the optical device according to the first modification.

  In the present embodiment, the lens surface portion 22 a is formed in a shape such that light incident from the lens surface portion 22 a is focused on the first light entrance / exit surface 21. For this reason, as shown in FIG. 7, the light receiving element 12 can be disposed immediately below the first light entrance / exit surface 21 of the optical element 20b. Similarly, the light emitting element 11 can be disposed immediately below the first light entrance / exit surface 21 of the optical element 20a. Therefore, the height of the optical device can be further reduced.

(Second modification)
FIG. 8 is a schematic diagram of a part of the optical device according to the second modification.

  In the above-described embodiment, the case where the lens surface portion 22a is formed only on the second light input / output surface 22 on the optical fiber 10 side of the first and second light input / output surfaces 21 and 22 has been described. However, the present invention is not limited to this configuration. For example, as shown in FIG. 8, a lens surface portion 22a is formed on the second light entrance / exit surface 22 on the optical fiber 10 side, and also on the first light entrance / exit surface 21 on the light receiving element 12 and light emitting element 11 side. A lens surface portion 21a having a positive optical power is formed. In this modification, the distance between the first light entrance / exit surface 21 and the focal point can be further shortened. Therefore, the height of the optical device can be further reduced.

(Third Modification)
FIG. 10 is a schematic diagram of an optical device according to a third modification.

  In the first embodiment, the case where each of the optical elements 20a and 20b is formed in a substantially triangular prism shape having the first and second light entrance / exit surfaces 21 and 22 and the light reflection surface 23 as side surfaces will be described. did. However, in the present invention, the shape of the optical element is not limited to this. The optical element may have any shape as long as it has the first and second light entrance / exit surfaces and the light reflection surface.

  For example, as shown in FIG. 10, in each of the optical elements 20a and 20b, a corner portion constituted by the first light entrance / exit surface 21 and the light reflection surface 23, the second light entrance / exit surface 22 and the light reflection. Each of the corners formed by the surface 23 may be chamfered.

  By forming the corner portion constituted by the second light entrance / exit surface 22 and the light reflection surface 23 in a chamfered shape, the dimension along the y direction of the optical elements 20a, 20b can be reduced. Therefore, the height of the optical device can be further reduced.

  On the other hand, by forming the corner portion constituted by the first light entrance / exit surface 21 and the light reflection surface 23 in a chamfered shape, the dimension along the x direction of the optical device can be reduced.

  Further, by forming at least one of the corners in a chamfered shape, the optical elements 20a and 20b, and thus the optical device can be reduced in weight.

  In addition, it is formed in each of a corner portion constituted by the first light entrance / exit surface 21 and the light reflection surface 23 and a corner portion constituted by the second light entrance / exit surface 22 and the light reflection surface 23. In addition, by using the flat portions 26 and 27 perpendicular to the x direction or the y direction as contact surfaces of the optical element with respect to the folder, the optical elements 20a and 20b can be easily positioned.

  In addition, in this modification, the example in which the plane part was formed in the corner | angular part formed in the chamfering shape was demonstrated. However, the surface of the corner formed in the chamfered shape may be a curved surface.

(Fourth modification)
FIG. 11 is a schematic perspective view of an optical element according to a fourth modification. FIG. 12 is a schematic exploded perspective view of a part of the optical device according to the fourth modification. FIG. 13 is a schematic side view of a part of the optical device according to the fourth modification. FIG. 14 is a schematic view of the XIV in FIG.

  As shown in FIG. 11, in the optical element 20 c in the present modification, a line convex portion 22 b is formed in a portion other than the portion located on the optical path of the second light entrance / exit surface 22. The convex portion 22 b is formed from one end portion to the other end portion in the width direction of the second light entrance / exit surface 22.

  As shown in FIGS. 12 to 14, the optical element 20 c is attached to the folder 30. Specifically, a concave portion 30a1 having a shape corresponding to the shape of the convex portion 22b is formed on the contact surface 30a of the folder 30. And the 2nd light entrance / exit surface 22 and the contact surface 30a of the optical element 20c are contact | abutting so that the convex part 22b and the recessed part 30a1 may fit. The second light entrance / exit surface 22 and the contact surface 30a are bonded to each other by an adhesive 28 applied to a portion 22c of the second light entrance / exit surface 22 that is separated from the portion located on the optical path by the convex portion 22b. Has been.

  By providing the convex portion 22b as in this modification, it is possible to suppress the adhesive 28 from flowing into a portion located on the optical path. Further, the positioning of the optical element 20c with respect to the folder 30 is facilitated by the convex portion 22b and the concave portion 30a1.

  In addition, in this modification, although the convex part 22b was formed, it may replace with the convex part 22b or may form a recessed part with the convex part 22b. Even in that case, the flow of the adhesive 28 to the portion located on the optical path can be suppressed.

  From the viewpoint of more effectively suppressing the flow of the adhesive 28 to the portion located on the optical path, it is preferable to provide a plurality of irregularities.

  Moreover, the shape of the unevenness to be formed is not particularly limited. For example, a convex or concave portion of a line having a trapezoidal cross section or a semicircular cross section, a cylindrical shape, a conical shape, or a convex or concave portion having a truncated cone shape may be provided.

  Moreover, although the example which provides an unevenness | corrugation in the 2nd light entrance / exit surface 22 was demonstrated in this modification, you may provide an unevenness | corrugation in the 1st light entrance / exit surface 21 or the light reflection surface 23. FIG. Further, two or more of the first and second light entrance / exit surfaces 21 and 22 and the light reflection surface 23 may be provided with unevenness.

DESCRIPTION OF SYMBOLS 1 ... Optical apparatus 10 ... Optical fiber 10a, 10b ... End 11 of optical fiber ... Light emitting element 12 ... Light receiving element 12a ... Light receiving surface 13 of light receiving element ... Circuit board 20a, 20b, 20c ... Optical element 21 ... First light Entry / exit surface 21a ... Lens surface portion 22 ... Second light entrance / exit surface 22a ... Lens surface portion 22b ... Convex portion 23 ... Light reflection surfaces 24, 25 ... Antireflection films 26, 27 ... Planar portion 28 ... Adhesive 30 ... Folder 30a ... Contact surface 30a1 ... concave portion

Claims (12)

An optical device comprising a light emitting / receiving element and an optical fiber having a distal end optical axis perpendicular to the optical axis of the light receiving / emitting element, and made of glass optics used for optical coupling between the light receiving / emitting element and the optical fiber An element,
A first light entrance / exit surface facing the light emitting / receiving element;
A second light entrance / exit surface facing the optical fiber;
A light reflecting surface that reflects light incident from one of the first and second light input / output surfaces to the other side of the first and second light input / output surfaces;
With
The second light entrance / exit surface is an optical element having a lens surface portion having a positive optical power. An optical element made of glass used for optical coupling between an optical fiber and a light emitting / receiving element,
First and second light entrance and exit surfaces;
A light reflecting surface that reflects light incident from one of the first and second light input / output surfaces to the other side of the first and second light input / output surfaces;
An optical element in which the second light entrance / exit surface has a lens surface portion having a positive optical power.   The optical element according to claim 1, wherein the lens surface portion is formed in a shape such that light incident from the lens surface portion is focused on the first light entrance / exit surface.   The optical element according to claim 1, wherein each of the first and second light entrance / exit surfaces has a lens surface portion having a positive optical power.   The optical element as described in any one of Claims 1-4 whose refractive index (nd) with respect to d line | wire is 1.75 or more.   The optical element according to any one of claims 1 to 5, wherein a plurality of the lens surface portions are formed in an array.   The optical element according to any one of claims 1 to 6, further comprising a reflection suppressing film formed on each of the first and second light entrance / exit surfaces.   The optical element according to claim 1, which is formed by a mold press.   The first and second light entry / exit surfaces and the light reflection surface are used as side surfaces, and a corner formed by the second light entry / exit surface and the light reflection surface is formed in a chamfered shape. The optical element according to claim 1, which has a triangular prism shape.   The optical element according to claim 9, wherein a corner portion formed by the first light entrance / exit surface and the light reflection surface is chamfered.   The unevenness | corrugation is formed in parts other than the part located on the at least 1 optical path of the said 1st and 2nd light entrance / exit surface and the said light reflection surface, It is any one of Claims 1-10. Optical elements. A light emitting / receiving element;
An optical fiber in which the optical axis of the tip is perpendicular to the optical axis of the light emitting and receiving element;
An optical element made of glass that optically couples the light emitting / receiving element and the optical fiber;
With
The optical element includes light incident from one of the first light input / output surface facing the light emitting / receiving element, the second light input / output surface facing the optical fiber, and the first and second light input / output surfaces. And a light reflecting surface that reflects the other side of the first and second light entrance / exit surfaces, and the second light entrance / exit surface has a lens surface portion having a positive optical power.

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