WO2017115413A1 - Optical transmission module and endoscope - Google Patents

Abstract

An optical transmission module 1 is provided with: an optical element 10; an optical fiber 20 wherein an end surface is a sloped reflecting surface 20SA; a holding member 40 having an end portion of the optical fiber 20 embedded therein; and a wiring board 50, wherein the optical element 10 is mounted on a first main surface 50SA, the holding member 40 is bonded to a second main surface 50SB, and a through hole H50 to be an optical path is formed. The holding member 40 is formed of a transparent resin, a bottom surface 40SA of the holding member 40 is in contact with the second main surface 50SB of the wiring board 50, and an angle θ of the reflecting surface 20SA with respect to a main surface 10SA of the optical element 10 is fixed to an angle at which light guided in the optical fiber 20 is to be optically coupled to the optical element 10.

Description

Optical transmission module and endoscope

The present invention includes an optical element, a wiring board on which the optical element is mounted, and an optical fiber that transmits an optical signal in which an optical axis is disposed in parallel to the main surface of the wiring board. And an endoscope including the light transmission module.

The endoscope has an image sensor such as a CCD at the rigid tip of the insertion portion. In recent years, use of an imaging device having a high pixel number for an endoscope has been studied. When an image sensor with a high number of pixels is used, the amount of signal transmitted from the image sensor to the signal processing device (processor) increases.

In order to minimize the invasiveness of an optical transmission module disposed at the rigid tip of an endoscope, downsizing, in particular, reduction in diameter is an important issue. For this reason, optical signal transmission through a thin optical fiber by an optical signal using an optical transmission module is preferable in place of electric signal transmission through a metal wiring by an electric signal.

An optical transmission module of an endoscope disclosed in Japanese Patent Application Laid-Open No. 2015-104387 includes an optical element, a wiring board, a holding member (ferrule) 40, and an optical fiber. In this optical transmission module, the optical element, the wiring board, and the holding member are arranged in the thickness direction of the optical element.

On the other hand, the diameter of the optical transmission module can be reduced by reflecting the end face of the optical fiber. For example, in Japanese Patent Laid-Open No. 10-325917, an end face of an optical fiber embedded in a holding part is processed into a reflecting surface, and light reflected by the reflecting surface is reflected in the optical axis direction of the optical fiber. An optical receiver that receives light with light receiving elements arranged in parallel is disclosed.

However, in an optical transmission module in which the end face of the optical fiber is a reflection surface, it is necessary to accurately define the angle formed by the main surface of the optical element and the reflection surface of the optical fiber, that is, the rotation direction of the optical fiber. For example, an adjustment process is necessary in which the optical fiber is rotated while the light is actually guided to find the rotation angle with the largest amount of light, and is fixed at the rotation angle. For this reason, although the optical transmission module which used the end surface of the optical fiber as a reflective surface is thin diameter, since the complicated adjustment process was performed, there existed a possibility that manufacture might not be easy.

Furthermore, in the optical fiber adjustment process, not only the rotation direction but also in-plane positioning adjustment with respect to the optical element is necessary.

Japanese Patent Laying-Open No. 2015-104387 Japanese Patent Laid-Open No. 10-325917

Embodiments of the present invention are intended to provide an optical transmission module that is easy to manufacture, and an endoscope that includes the optical transmission module at a rigid distal end portion of an insertion portion.

An optical transmission module according to an embodiment of the present invention includes an optical element that includes a light-emitting element or a light-receiving element, a core and a clad, a circular cross section, and a reflective surface with an inclined end surface; A holding member in which an end of the optical fiber is embedded; a first main surface; and a second main surface opposite to the first main surface, wherein the optical element is disposed on the first main surface. And a wiring board in which the holding member is bonded to the second main surface, and a through hole serving as an optical path is formed. The holding member is made of a transparent resin, and the holding The bottom surface of the member is in contact with the second main surface of the wiring board, and the angle of the reflection surface with respect to the main surface of the optical element is an angle at which light guided through the optical fiber is optically coupled to the optical element. It is fixed to.

An endoscope according to another embodiment includes an optical element that includes a light-emitting element or a light-receiving element, a core and a clad, a circular cross section, and a reflecting surface having an inclined end surface, A holding member in which an end of the optical fiber is embedded; a first main surface; and a second main surface opposite to the first main surface, wherein the optical element is disposed on the first main surface. And a wiring board in which the holding member is bonded to the second main surface, and a through hole serving as an optical path is formed. The holding member is made of a transparent resin, and the holding The bottom surface of the member is in contact with the second main surface of the wiring board, and the angle of the reflection surface with respect to the main surface of the optical element is an angle at which light guided through the optical fiber is optically coupled to the optical element. The optical transmission module fixed to the head is provided at the rigid tip of the insertion portion.

According to the embodiment of the present invention, it is possible to provide an optical transmission module that is easy to manufacture, and an endoscope that includes the optical transmission module at a rigid distal end portion of an insertion portion.

It is an exploded view of the optical transmission module of 1st Embodiment. FIG. 2 is a cross-sectional view along the optical axis direction of the optical transmission module according to the first embodiment, that is, along the line II-II in FIG. It is sectional drawing of the optical transmission module of 1st Embodiment of the optical axis orthogonal direction. It is sectional drawing of an optical axis orthogonal direction for demonstrating the structure of the optical transmission module of the modification 1 of 1st Embodiment. It is sectional drawing of an optical axis orthogonal direction for demonstrating the structure of the optical transmission module of the modification 2 of 1st Embodiment. It is sectional drawing of an optical axis orthogonal direction for demonstrating the structure of the optical transmission module of the modification 3 of 1st Embodiment. It is a perspective view of the optical transmission module of the modification 4 of 1st Embodiment. It is sectional drawing of an optical axis orthogonal direction for demonstrating the structure of the optical transmission module of the modification 4 of 1st Embodiment. It is sectional drawing of an optical axis orthogonal direction for demonstrating the structure of the optical transmission module of the modification 5 of 1st Embodiment. It is a perspective view of the optical transmission module of the modification 6 of 1st Embodiment. It is an exploded view of the optical transmission module of 2nd Embodiment. It is an exploded view of the optical transmission module of the modification 1 of 2nd Embodiment. It is an exploded view of the optical transmission module of the modification 2 of 2nd Embodiment. It is an exploded view of the optical transmission module of the modification 3 of 2nd Embodiment. It is an exploded view of the optical transmission module of the modification 4 of 2nd Embodiment. It is an external view of the endoscope of 3rd Embodiment.

<First Embodiment>
As shown in FIGS. 1 to 3, the optical transmission module 1 of this embodiment includes an optical element 10, an optical fiber 20, a cable 30, a holding member 40, and a wiring board 50. The optical element 10 and the cable 30 are joined to the wiring board 50, and the holding member 40 in which the end of the optical fiber 20 is embedded is adhered. Since the light emitting surface 10SA of the optical element 10 and the optical axis of the optical fiber 20 are arranged in parallel, the optical transmission module 1 has a small diameter.

Note that all the drawings are schematic, and it should be noted that the relationship between the thickness and width of each part, the ratio of the thickness of each part, and the like are different from the actual ones. In some cases, there are portions in which the dimensional relationships and ratios are different. Moreover, illustration of some components may be omitted. In FIG. 1 and the like, the left side, that is, the tip direction (X-axis value increasing direction) of the optical fiber 20 is referred to as “front”, and the direction of the optical fiber 20 relative to the optical element 10, that is, the Z-axis value increasing direction is “ It is said "on."

The light emitted upward from the optical element 10 enters the side surface of the optical fiber 20 through the through hole H50 of the wiring board 50, is reflected by the reflecting surface 20SA, and the optical path is bent 90 degrees, and the inside of the core 21 is reflected. It is guided backward. The bottom surface 40SA of the holding member 40 in which the end of the optical fiber 20 is embedded is brought into contact with the second main surface 50SB of the wiring board 50, so that the rotation angle of the optical fiber 20 is guided through the optical fiber 20. Is fixed at an angle θ at which light is efficiently optically coupled with the optical element 10.

The optical element 10 is, for example, a VCSEL (Vertical / Cavity / Surface / Emitting / LASER: vertical cavity surface emitting laser) type light-emitting element having a light-emitting unit 11 that outputs light of an optical signal to the light-emitting surface 10SA. For example, the ultra-compact optical element 10 having a planar view size of 250 μm × 300 μm has a light emitting unit 11 having a diameter of 20 μm and a bonding bump 12 for supplying a driving signal to the light emitting unit 11 on the light emitting surface 10SA. . The optical element 10 emits light in a direction perpendicular to the light emitting surface 10SA.

The bonding bumps 12 have a height of 10 μm to 100 μm and are, for example, stud bumps, plating bumps, ball bumps, or the like made of gold or solder.

The optical fiber 20 having a circular cross section is, for example, MMF (Multi Mode Fiber) that is easy to align. The core 21 that transmits light has a diameter of 50 μm, and the cladding 22 that covers the outer periphery of the core 21 has a diameter of 125 μm. For example, the core 21 has a refractive index of 1.50 to 1.60, and the refractive index is 0.01 or more higher than that of the cladding 22.

The end of the optical fiber 20 is embedded in the holding member 40. The holding member 40 is made of a transparent resin having the same refractive index as that of the clad 22 of the optical fiber 20. Note that the transparent resin may be light-shielding at other wavelengths, for example, visible light wavelengths, as long as the transmittance at the wavelength of the optical signal is high.

For example, a liquid ultraviolet curable resin or a thermosetting resin is poured into a mold that is arranged so that the outer peripheral surface of the end portion of the optical fiber 20 is in contact with the bottom surface, and the optical fiber 20 is cured. The end portion is embedded in the holding member 40.

When the end of the optical fiber 20 is cut obliquely together with the holding member 40, the end surface of the optical fiber 20 is processed into an inclined reflecting surface 20SA. The inclination angle θ of the reflecting surface 20SA is an angle with respect to the bottom surface 40SA of the holding member 40. As will be described later, the inclination angle θ is appropriately set in the relative positional relationship with the optical element 10.

Of course, the end portion of the optical fiber 20 on which the reflecting surface 20SA is formed in advance may be arranged on the bottom surface of the mold with the rotation angle defined, and embedded in the holding member 40 made of a curable resin.

Further, even if a holding member having a bottom surface having an angle θ with respect to the reflecting surface 20SA of the optical fiber 20 is manufactured by grinding / polishing a part of the resin body in which the optical fiber 20 on which the reflecting surface 20SA is formed is embedded. Good.

If a part of the outer peripheral surface of the clad 22 is exposed on the bottom surface 40SA of the holding member 40, the optical path length does not increase even if the optical fiber 20 is embedded in the holding member 40.

In addition, when the outer peripheral surface of the clad is not exposed on the bottom surface of the holding member, it is preferable to perform grinding / polishing in order to shorten the optical path length.

Further, a reflective film may be provided on the reflective surface 20SA. For example, light can be reflected more efficiently by disposing a reflective film made of gold or aluminum having a high reflectivity by sputtering.

The wiring board 50 has a first main surface 50SA and a second main surface 50SB facing the first main surface 50SA. An electrode 51 bonded to the bonding bump 12 of the optical element 10 is disposed on the first main surface 50SA of the wiring board 50. The second main surface 50SB is provided with a bonding electrode 52 that is electrically connected to the bonding bump 12 via a through wiring (not shown) or the like. The cable 30 is bonded to the bonding electrode 52 of the wiring board 50 by, for example, solder 54.

For the substrate of the wiring board 50, a resin substrate, a ceramic substrate, a glass epoxy substrate, a glass substrate, a silicon substrate, or the like is used. The wiring board 50 is particularly preferably an FPC (Flexible printed circuit) substrate based on polyimide or the like from the viewpoint of miniaturization and flexibility.

An underfill material, a side fill material, or the like is injected as a sealing member 19 between the optical element 10 and the wiring board 50. An electronic component 59 such as a chip capacitor or an IC is mounted on the second main surface 50SB of the wiring board 50.

The wiring board 50 has a through hole H50 serving as an optical path through which light emitted from the light emitting unit 11 passes. The second main surface 50SB of the wiring board 50 is bonded with an adhesive 45 made of resin, for example, with the bottom surface of the holding member 40 in contact therewith. On the other hand, the optical element 10 is mounted on the first main surface 50SA of the wiring board 50 in a state where the light emitting portion 11 is disposed at a position facing the through hole H50 of the wiring board 50. The light emitting surface 10SA of the optical element 10 is arranged in parallel with the first main surface 50SA and the second main surface 50SB of the wiring board 50.

For this reason, when the bottom surface 40SA of the holding member 40 is fixed in contact with the second main surface 50SB of the wiring board 50, the angle θ of the reflection surface 20SA with respect to the light emitting surface (main surface) 10SA of the optical element 10 becomes light. The light guided through the fiber 20 is automatically fixed at an angle θ at which the optical element 10 is optically coupled. For this reason, the optical transmission module 1 is easy to manufacture.

Note that the optical coupling angle θ means an angle at which the amount of light is efficiently reflected at 80% or more when the amount of light when the light is reflected most efficiently is 100%.

For example, if the inclination angle is 45 degrees, the light emitted from the light emitting portion 11 of the optical element 10 perpendicularly to the light emitting surface 10SA is bent 90 degrees at the reflecting surface 20SA. If the inclination angle θ is not less than 35 degrees and not more than 55 degrees, the light can be efficiently guided to the core 21 of the optical fiber 20.

The entire optical transmission module 1 including the end of the optical fiber 20 may be covered with a light shielding resin. The light shielding resin prevents light leakage from the optical element 10 and improves the reflection efficiency because the inclined surface 20SA is also covered with the light shielding resin.

Since the rotation direction of the optical fiber 20 with respect to the optical element 10 is automatically defined, the optical transmission module 1 does not require a complicated adjustment process and is easy to manufacture.

<Modification of First Embodiment>
Next, optical transmission modules 1A to 1F of Modifications 1 to 6 of the first embodiment will be described. Since the optical transmission modules 1A to 1F are similar to the optical transmission module 1 and have the same effects, the same reference numerals are given to components having the same functions, and the description thereof is omitted. In the following drawings, hatching indicating the material of the constituent elements is omitted.

<Variation 1 of the first embodiment>
In the optical transmission module 1A of the present modification shown in FIG. 4, the optical element 10A is a light receiving element such as a photodiode (PD). For example, an optical element made of a photodiode converts light incident from the vertical direction to the light receiving surface 10SA into an electrical signal and outputs the electrical signal. For example, an ultra-small light receiving element having a planar view size of 350 μm × 300 μm includes a light receiving unit 11A having a diameter of 100 μm, and a bonding bump 12 for outputting a received electric signal electrically connected to the light receiving unit 11A, On the light receiving surface 10SA.

The optical transmission module 1 </ b> A is fixed in a state where the bottom surface 40 </ b> SA of the holding member 40 is in contact with the second main surface 50 </ b> SB of the wiring board 50 in the same manner as the optical transmission module 1, thereby The angle θ with respect to the light receiving surface (main surface) 10SA is automatically fixed to an angle at which the light guided through the optical fiber 20 is efficiently optically coupled with the optical element 10A. For this reason, the optical transmission module 1A is easy to manufacture.

<Modification 2 of the first embodiment>
In the optical transmission module 1B of this modification shown in FIG. 5, the width L40 of the bottom surface 40SA of the holding member 40B in the longitudinal direction of the optical fiber 20, that is, the direction orthogonal to the optical axis (Y-axis direction) is Is the same.

When the light guided through the core 21 of the optical fiber 20 is reflected by the reflecting surface 20SA, the optical path is bent in the direction of the light receiving unit 11A (downward direction: Z-axis value decreasing direction) and enters the clad 22. Since the light guided through the core 21 is reflected at the interface with the clad 22, the optical path does not spread. However, when the light is reflected by the reflecting surface 20SA and enters the clad 22 from the core 21, the optical path is widened. The size of the optical path, that is, the width L20 when observed from the optical path direction, increases or decreases depending on the numerical aperture (NA) of the optical fiber 20 or the like.

For example, in the optical fiber 20 in which the refractive index of the core 21 is 1.48 and the diameter is 50 μm, the refractive index of the cladding 22 is 1.46, the diameter is 125 μm, and NA = 0.2, the optical path size at the bottom surface 40SA is shown. The width L20 is 67 μm. When the diameter of the core 21 is 62.5 μm, the width L20 is 86 μm.

That is, when the outer peripheral surface of the cladding 22 is exposed to the bottom surface 40SA, the optical loss increases even if the width L40 of the bottom surface 40SA of the holding member 40B is the same as the outer diameter R20 of the cladding 22. Absent. The optical transmission module 1B can be easily reduced in diameter by reducing the width L40.

<Modification 3 of the first embodiment>
In the optical transmission module 1C of the present modification shown in FIG. 6, a notch N40 is formed at the intersection of the bottom surface 40SA and the side surface 40SS of the holding member 40C, and the notch N40 is filled with the adhesive 45. .

Since the adhesive 45 is filled in the cutout N40, the spread of the fillet is small. For this reason, the diameter of the optical transmission module 1C can be easily reduced.

<Modification 4 of the first embodiment>
The optical transmission module 1D of this modification shown in FIGS. 7 and 8A has a wall surface when observed from a direction parallel to the optical axis of the optical fiber 20 on the side formed by the bottom surface 40SA of the holding member 40D and one side surface 40SS. A notch N40D having a curved shape is formed. The adhesive 45D filled in the notch N40D is transparent and has a refractive index substantially the same as that of the cladding 22.

As shown in FIG. 8A, since the holding member 40D has a cutout N40D formed on only one side surface, the shape when viewed from a direction parallel to the optical axis is “tears”.

The optical transmission module 1D can be easily reduced in diameter. Since the refractive index of the adhesive 45D is the same as the refractive index of the clad 22, the optical loss increases even if the width L40 of the bottom surface 40SA of the holding member 40D is smaller than the width L20 of the optical path at the bottom surface 40SA. There is no.

<Modification 5 of the first embodiment>
In the optical transmission module 1 </ b> E of this modification shown in FIG. 8B, the holding member 40 </ b> E has a “bell shape” whose upper surface is curved along the outer shape of the optical fiber 20.

That is, the shape of the holding member 40E in the region that does not become the optical path of the optical fiber 20 can be changed as appropriate in order to reduce the diameter.

<Modification 6 of the first embodiment>
In the optical transmission module 1F of the present modification shown in FIG. 9, the notch N40F is not formed in the portion of the side surface 40SS of the holding member 40F that faces the end surface.

Therefore, there is no possibility that the excessively applied adhesive 45 enters the optical path. That is, as long as the holding member 40F can be fixed to the wiring board 50, the adhesive 45 may be disposed only on a part of the side surface of the holding member.

<Second Embodiment and Modifications of Second Embodiment>
Next, the optical transmission module 1G of the second embodiment and the optical transmission modules 1H to 1K of the modifications 1 to 4 of the second embodiment will be described. Since the optical transmission modules 1G to 1K are similar to the optical transmission modules 1 and 1A to 1F and have the same effects, components having the same function are denoted by the same reference numerals and description thereof is omitted.

In order to guide light to the optical fiber 20 efficiently, not only the rotation angle θ but also the positioning in the in-plane direction (XY plane direction) with respect to the optical elements 10 and 10A is important. For example, it is preferable to arrange the center of the reflecting surface 20SA of the optical fiber 20 directly above the light emitting unit 11. In the optical transmission module 1G of the second embodiment and the optical transmission modules 1H to 1K of the first to fourth modifications of the second embodiment, the in-plane positioning is automatically performed by the holding member coming into contact with the positioning member. Is called.

Hereinafter, an optical transmission module having the optical element 10 as a light emitting element will be described as an example, but an optical transmission module having the optical element 10A as a light receiving element has the same effect.

Second Embodiment
The optical transmission module 1G shown in FIG. 10 has a recess T60 in which the end of the holding member 40 is inserted and fitted into the positioning member 60 disposed on the second main surface 50SB of the wiring board 50.

The positioning member 60 is made of, for example, ceramic, Si (silicon), glass, resin, or metal. The recess T60 has a groove shape with an opening on the bottom surface of the positioning member 60. The inner dimension of the recess T60 is substantially the same as the outer dimension of the holding member 40 to be inserted. Here, “substantially the same” means that both dimensions are substantially the same so that the outer peripheral surface of the holding member 40 and the wall surface of the recess T60 are in contact with each other. For example, the inner dimension of the recess T60 is made larger than the outer dimension of the holding member 40 by 1 μm to 5 μm.

The holding member 40 has its bottom surface 40SA in contact with the second main surface 50SB of the wiring board 50, whereby the rotation direction is automatically defined, and the end portion is fitted with the recess T60 of the positioning member 60. Positioning in the in-plane direction (XY direction) is automatically performed.

For this reason, the optical transmission module 1G is easier to manufacture than the optical transmission module 1 or the like.

<Modification Example 1 of Second Embodiment>
As shown in FIG. 11, in the optical transmission module 1H of this modification, there is a hole H60 on the upper surface of the recess T60 of the positioning member 60H. The hole H <b> 60 is located immediately above the light emitting unit 11 of the optical element 10.

When positioning the positioning member 60H on the wiring board 50 on which the optical element 10 is mounted, it is necessary to perform positioning in the in-plane direction (XY direction).

In the optical transmission module 1H, the light emitting portion 11 of the optical element 10 disposed on the first main surface 50SA of the wiring board 50 is viewed from above through the hole H60 of the positioning member 60H and the through hole H50 of the wiring board 50. I can observe. For example, the optical alignment can be accurately performed by adjusting the position of the positioning member 60H to the position where the light emitting unit 11 is located at the center of the hole H60.

<Modification 2 of the second embodiment>
As shown in FIG. 12, in the optical transmission module 1I of the present modification, the positioning member 60I has an L-shaped wall shape and has markers 65 (65A, 65B) on the upper surface. The marker 65 indicates the positional relationship with the light element 11 directly above the optical element 10.

That is, the marker 65A indicates the position of the optical fiber 20 in the optical axis direction (X direction), and the marker 65B indicates the position of the optical fiber 20 in the optical axis orthogonal direction (Y direction). The intersection of the extension line of the marker 65A and the extension line of the marker 65B is directly above the light emitting unit 11 of the optical element 10.

The optical transmission module 1I can be easily aligned by adjusting and fixing the position of the positioning member 60I with reference to the marker 65.

<Modification 3 of the second embodiment>
As shown in FIG. 13, in the optical transmission module 1J of this modification, the positioning member is a bump 53 (53A, 53B) disposed on the second main surface of the wiring board 50J. That is, the position in the in-plane direction is automatically defined by the end of the holding member 40 coming into contact with the bump 53 of the wiring board 50J.

The light transmission module 1J has a small diameter because it does not have a large positioning member.

The wiring board 50J is provided with a first bump 53A that is an optical axis direction (X direction) positioning member and a second bump 53B that is an optical axis orthogonal direction (Y direction) positioning member. Yes. In the case of positioning in the optical axis direction or the direction orthogonal to the optical axis, the first bump 53A or the second bump 53B may be provided.

In addition, when the height of the bump 53 is low, the bump 53 may be constituted by a two-step bump.

<Modification 4 of the second embodiment>
As shown in FIG. 14, in the optical transmission module 1K of the present modification, the positioning member is an electronic component 59 (59A, 59B) mounted on the second main surface 50SB of the wiring board 50K. That is, the holding member 40 has its end portion in contact with the electronic component 59 of the wiring board 50K, so that the position in the in-plane direction is automatically defined.

The electronic component 59 (59A, 59B) is bonded to an electrode pad provided when the wiring board 50K is manufactured. The electronic component 59 for forming the electric circuit is a component necessary for the optical transmission module 1K, and a function of a positioning member is added to the electronic component 59. The electronic component 59 has a necessary and sufficient height for positioning.

In the optical transmission module 1K, it is not necessary to arrange a positioning-dedicated bump on the wiring board 50K. Since the area of the second main surface 50SB of the wiring board 50K can be reduced, the optical transmission module 1K has the effect of the optical transmission module 1J and has a smaller diameter.

The positioning member may be at least one of the bump 53 and the electronic component 59. That is, for example, positioning in the direction perpendicular to the optical axis may be performed by the bumps 53 and positioning in the optical axis direction may be performed by the electronic component 59. The positioning member may be a plurality of electronic components of different types.

In the optical transmission module 1G of the second embodiment and the optical transmission modules 1H to 1K of the first to fourth modifications of the second embodiment, the holding members 40A to 40F of the first modification to the first modification of the first embodiment It goes without saying that the same effect is obtained by using the holding members having the same configuration.

<Third Embodiment>
Next, an endoscope 9 according to a third embodiment will be described.

As shown in FIG. 15, the endoscope 9 includes an insertion portion 9B in which any one of the light transmission modules 1 to 1K is disposed at the rigid distal end portion 9A, and an operation disposed at the proximal end side of the insertion portion 9B. A unit 9C and a universal cord 9D extending from the operation unit 9C. For example, an optical signal transmitted from the optical transmission module 1 disposed in the hard tip portion 9A and guided by the optical fiber 20 inserted through the insertion portion 9B is, for example, an optical transmission disposed in the operation portion 9C. It is converted into an electrical signal by the module 1X.

Since the endoscope 9 has the light transmission modules 1 to 1K having a small diameter, the hard tip portion 9A has a small diameter. Furthermore, the endoscope 9 is easy to manufacture because it includes the light transmission modules 1 to 1K.

The present invention is not limited to the above-described embodiments and modifications, and various modifications, combinations, and applications are possible without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1, 1A-1K ... Optical transmission module 9 ... Endoscope 10 ... Optical element 20 ... Optical fiber 20SA ... Reflecting surface 30 ... Cable 40 ... Holding member 45 ... -Adhesive 50 ... Wiring board 59 ... Electronic component 60 ... Positioning member 65 ... Marker

Claims (13)

An optical element comprising a light emitting element or a light receiving element;
An optical fiber having a core and a clad, having a circular cross section, and a reflecting surface having an inclined end surface;
A holding member in which an end of the optical fiber is embedded;
A first main surface and a second main surface opposite to the first main surface, the optical element being mounted on the first main surface, and the holding on the second main surface; An optical transmission module comprising a wiring board having a member bonded thereto and a through hole serving as an optical path;
The holding member is made of a transparent resin,
The bottom surface of the holding member is in contact with the second main surface of the wiring board, and the angle of the reflection surface with respect to the main surface of the optical element is such that light guided through the optical fiber is optically coupled to the optical element. An optical transmission module characterized by being fixed at an angle. The optical transmission module according to claim 1, wherein a part of the outer peripheral surface of the clad is exposed on the bottom surface of the holding member. 3. The optical transmission module according to claim 1, wherein the bottom surface of the holding member is larger than an optical path on the bottom surface of the light. The optical transmission module according to claim 3, wherein a width of the bottom surface of the holding member is the same as an outer diameter of the clad. A cutout is formed in the holding member,
The optical transmission module according to claim 1, wherein the holding member is fixed to the wiring board by a transparent adhesive injected into the notch. The said notch is formed in one side surface side of the said holding member, and the wall surface when observed from the direction parallel to the optical axis of the said optical fiber is curvilinear. Optical transmission module. The optical transmission module according to claim 5 or 6, wherein the notch of the holding member is not formed in a portion facing the end surface. 8. The optical transmission according to claim 1, wherein a positioning member with which the holding member abuts is disposed on the second main surface of the wiring board. 9. module. 9. The optical transmission module according to claim 8, wherein the positioning member has a recess into which an end of the holding member is inserted. There is a hole in the upper surface of the concave portion of the positioning member,
The optical transmission module according to claim 9, wherein the hole is located immediately above the light emitting part or the light receiving part of the optical element. The optical transmission module according to claim 9, wherein the positioning member includes a marker indicating a positional relationship with a light emitting part or a light receiving part of the optical element. The optical transmission module according to claim 8, wherein the positioning member is at least one of a bump and an electronic component with which an end of the holding member is in contact. An endoscope comprising the optical transmission module according to any one of claims 1 to 12 at a rigid distal end portion of an insertion portion.

Images