JP2015097588A - Optical transmission module and endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical transmission module 1 in which stress is not applied to an optical fiber 50 and which can transmit an optical signal in a stable manner.SOLUTION: An optical transmission module 1 includes: an optical element 10 having a light emitting part 11 for converting an electric signal to an optical signal; a holding member 40 having a through-hole 40H disposed so that the light emitting part 11 is opposed to the through-hole 40H; and an optical fiber 50 for transmitting the optical signal. The leading end of the optical fiber 50 is inserted into the through-hole 40H of the holding member 40, and freely moves inside the through-hole 40H.

Description

  The present invention provides an optical transmission module comprising: an optical element that generates an optical signal; an optical fiber that transmits the optical signal; and a holding member having a through-hole into which the optical fiber is inserted; and the optical transmission The present invention relates to an endoscope having a module.

  The endoscope has an image pickup device such as a CCD at a rigid distal end portion of an elongated 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 large number of pixels is used, the amount of signal transmitted from the image sensor to the signal processing device (processor) increases. Therefore, instead of electric signal transmission via metal wiring using electric signals, optical signals are used. Optical signal transmission through a thin optical fiber is preferred. For optical signal transmission, an E / O module (electric-optical converter) that converts an electric signal into an optical signal and an O / E module (optical-electric converter) that converts an optical signal into an electric signal are used. .

  For example, Japanese Patent Laid-Open No. 2013-025092 discloses an optical element that inputs or outputs an optical signal, a substrate on which the optical element is mounted, and an optical fiber insertion that transmits an optical signal that is input and output from the optical element. An optical transmission module is disclosed that includes a holding portion having a through hole and arranged side by side in the thickness direction of the optical element.

  Here, the optical fiber is not strong in the longitudinal direction. For this reason, when the flexible insertion part of an endoscope deform | transforms, when tensile stress / compressive stress is repeatedly applied to a longitudinal direction, it may be damaged or broken. In addition, the other member in the insertion portion and the optical fiber may be entangled, and the optical fiber may be damaged or torsional stressed. If the optical fiber is broken, it becomes difficult to transmit optical signals.

JP 2013-025092 A

  Embodiments of the present invention provide an optical transmission module capable of transmitting an optical signal stably without applying stress to the optical fiber, and an optical signal stably without applying stress to the optical fiber. An object of the present invention is to provide an endoscope having a light transmission module capable of transmitting.

An endoscope according to an embodiment of the present invention includes an insertion portion in which a rigid distal end portion, a bending portion for changing the direction of the rigid distal end portion, and a flexible flexible portion are connected, and an insertion portion of the insertion portion. An optical fiber that transmits an optical signal inserted therethrough, and
The rigid tip has an imaging element, an optical element having a light emitting part that converts an electrical signal output from the imaging element into the optical signal, a through hole, and the light emitting part and the through hole are opposed to each other. A holding member, a first main surface, and a second main surface, wherein the optical element and the first main surface are joined, and the holding member and the second main surface are joined together. The surface is joined, and a wiring board having a hole at a position facing the through hole and the light emitting part is disposed,
The optical fiber has a distal end inserted into the through hole of the holding member, and moves inside the through hole with deformation of the curved portion, and at least the distal end of the optical fiber or the through hole A lubricating layer is disposed on either of the first locking member for preventing the optical fiber from being pulled out from the through hole, and a second member for preventing contact between the optical fiber and the optical element. A stop member.

An endoscope according to another embodiment includes an insertion portion in which a rigid distal end portion, a bending portion for changing the direction of the rigid distal end portion, a flexible soft portion are connected, and an interior of the insertion portion. An optical fiber for transmitting the inserted optical signal,
The rigid tip has an imaging element and an optical element having a light emitting part that converts an electrical signal output from the imaging element into an optical signal, and a through hole. The light emitting part and the through hole are arranged to face each other. A holding member, and
The tip of the optical fiber is inserted into the through hole of the holding member, and the optical fiber moves freely within the through hole.

An optical transmission module according to another embodiment includes an optical element having a light emitting unit that converts an electric signal into an optical signal, a through hole, and the light emitting unit and the through hole are arranged so as to face each other. A member, and an optical fiber that transmits the optical signal,
The tip of the optical fiber is inserted into the through hole of the holding member, and the optical fiber moves freely within the through hole.

  According to the embodiment of the present invention, no stress is applied to the optical fiber, and the optical transmission module capable of stably transmitting the optical signal and the optical signal stably without applying the stress to the optical fiber. It is possible to provide an endoscope having a light transmission module capable of transmitting

It is sectional drawing of the optical transmission module of 1st Embodiment. It is sectional drawing of the optical transmission module of 1st Embodiment. It is sectional drawing of the optical transmission module of the modification 1 of 1st Embodiment. It is sectional drawing of the optical transmission module of the modification 2 of 1st Embodiment. It is sectional drawing of the optical transmission module of the modification 3 of 1st Embodiment. It is sectional drawing of the optical transmission module of the modification 4 of 1st Embodiment. It is a perspective view of the endoscope of a 2nd embodiment. It is sectional drawing which shows operation | movement of the bending part of the endoscope of 2nd Embodiment. It is sectional drawing which shows operation | movement of the bending part of the endoscope of 2nd Embodiment.

<First Embodiment>
The optical transmission module 1 according to the first embodiment will be described with reference to FIGS. 1 and 2. The optical transmission module 1 of this embodiment is an E / O module that converts an electrical signal into an optical signal and transmits the optical signal.

  The optical transmission module 1 includes an optical element 10, a wiring board 20, a holding member (also referred to as a ferrule) 40, and an optical fiber 50. In the optical transmission module 1, the optical element 10, the wiring board 20, and the holding member 40 are arranged side by side in the thickness direction (Z direction) of the optical element 10.

  The optical element 10 is a surface emitting laser chip having a light emitting unit 11 that outputs light of an optical signal. For example, the ultra-small optical element 10 having a planar size of 250 μm × 300 μm has a light emitting part 11 having a diameter of 20 μm and an electrode 12 for supplying a driving signal to the light emitting part 11 on the main surface.

  On the other hand, for example, the optical fiber 50 having a diameter of 125 μm includes a core having a diameter of 50 μm for transmitting light and a clad covering the outer periphery of the core.

  The distal end portion of the optical fiber 50 is inserted into the through hole 40H of the substantially rectangular parallelepiped holding member 40 bonded onto the optical element 10. By inserting the optical fiber 50 into the through hole 40H, the light emitting portion 11 of the optical element 10 and the optical fiber 50 are positioned. The major feature of the optical transmission module 1 is that the optical fiber 50 is not fixed to the holding member 40.

  The flat wiring board 20 having the first main surface 20SA and the second main surface 20SB has a hole 20H serving as an optical path. The optical element 10 is flip-chip mounted on the first main surface 20SA in a state where the light emitting portion 11 is disposed at a position facing the hole 20H of the wiring board 20. That is, the wiring board 20 has a plurality of electrodes 12 of the optical element 10 and an electrode pad 21 to which each is bonded. As the base of the wiring board 20, an FPC board, a ceramic board, a glass epoxy board, a glass board, a silicon board, or the like is used.

  For example, Au bumps that are the electrodes 12 of the optical element 10 are ultrasonically bonded to the electrode pads 21 of the wiring board 20. In addition, although adhesives, such as an underfill material and a side fill material, may be inject | poured into a junction part, it is preferable to provide the insertion part for the air in the through-hole 40H to go in and out.

  Solder paste or the like may be printed on the wiring board 20 and the optical element 10 may be placed at a predetermined position, and then the solder may be melted and mounted by reflow or the like. The wiring board 20 transmits an electrode pad (not shown) connected to the image sensor 90 (FIG. 8) and the metal wiring 90M (FIG. 8) and an electric signal transmitted from the image sensor 90 to the electrode pad 21. It has wiring (not shown). Further, the wiring board 20 may include a processing circuit for converting an electric signal transmitted from the image sensor 90 into a drive signal for the optical element 10.

  As already described, the holding member 40 is formed with a cylindrical through hole 40H having an inner diameter slightly larger than the outer diameter of the optical fiber 50 to be inserted. For example, the inner diameter of the through hole 40H is made larger by 1 μm to 5 μm than the outer diameter of the optical fiber 50.

  The through hole 40H may have a prismatic shape as long as the optical fiber 50 can be held by the wall surface in addition to the cylindrical shape. The material of the holding member 40 is a metal member such as ceramic, Si, glass, or SUS. The holding member 40 may have a substantially cylindrical shape or a substantially conical shape.

  The holding member 40 is joined to the second main surface 20SB of the wiring board 20 via the adhesive layer 30 in a state where the through hole 40H is disposed at a position facing the hole 20H of the wiring board 20. For example, the adhesive layer 30 made of a thermosetting resin is not disposed in a region where the through hole 40H and the hole 20H are opposed to each other.

  And in the optical transmission module 1 of embodiment, the optical fiber 50 by which the front-end | tip part was inserted in the through-hole 40H is not being fixed to the holding member 40. FIG. For this reason, the optical fiber 50 freely moves inside the through hole 40H.

  As shown in FIG. 2, when a tensile stress PS is applied to the optical fiber 50, the tip surface 50SA moves rearward, that is, toward the inlet side of the through hole 40H. Conversely, when compressive stress is applied to the optical fiber 50, the distal end surface 50SA moves forward, that is, toward the optical element.

  As will be described later, the length D of the holding member 40, that is, the length (depth) D of the through hole 40H is set based on the maximum value of the force (deformation amount) that may be applied to the optical fiber 50. Is done.

  In the optical transmission module 1, in order for the optical fiber 50 to move smoothly through the through hole 40H, the sliding characteristics between the outer peripheral surface of the optical fiber 50 and the wall surface of the through hole 40H are good. Is preferred. For example, the friction coefficient μ between the optical fiber 50 and the through hole 40H is preferably 0.5 or less.

  Here, the friction coefficient μ is a static friction coefficient measured according to JIS K7218. If the friction coefficient μ is 0.5 or less, a large stress is not applied to the optical fiber 50.

  For example, when both are made of glass, the friction coefficient μ is as high as about 0.7. In order to reduce the friction coefficient μ, the surface roughness of the contact surface is adjusted to an appropriate value, or unevenness is provided on the contact surface so as to make contact with a plurality of points / lines instead of surface contact.

In the optical transmission module 1, even if a force is applied to the optical fiber 50, the stress is released by moving inside the through hole 40 </ b> H, so that the optical fiber 50 is not damaged or broken.
The optical transmission module 1 can transmit an optical signal stably without applying a large stress to the optical fiber 50.

<Modification>
Next, optical transmission modules 1A to 1D according to modifications of the first embodiment will be described. Since the optical transmission modules 1A to 1D of the modification are similar to the optical transmission module 1, the same reference numerals are given to components having the same functions, and description thereof will be omitted.

  As will be described below, the light transmission modules 1A to 1D have the effects of the light transmission module 1, and each has a unique effect.

<Modification 1>
As shown in FIG. 3, in the optical transmission module 1A of Modification 1, the optical element 10A and the holding member 40A are disposed on one side of the wiring board 20A. The electrode 12A of the optical element 10A and the electrode pad 21A of the wiring board 20A are connected by a wire bonding wiring 49.

  The holding member 40A having a recess in which the optical element 10A is accommodated is joined to the wiring board 20A via an adhesive layer (not shown) so that the through hole 40H faces the light emitting part 11 of the optical element 10A.

  Since the optical fiber 50 is not fixed to the holding member 40A, the optical fiber 50 freely moves inside the through hole 40H.

  The optical transmission module 1A is not required to be provided with a hole serving as an optical path in the wiring board, and is easy to manufacture because the two elements need only be aligned with the optical element 10A and the holding member 40A.

<Modification 2>
As already described, the friction coefficient μ between the optical fiber 50 and the holding member 40 is preferably 0.5 or less. However, the material of the optical fiber 50 is limited to glass or resin. For this reason, the choice of the material of the holding member 40 is limited. Further, when the surface roughness or the like of the contact surface is adjusted, peeling may occur due to sliding.

  As shown in FIG. 4, in the optical transmission module 1 </ b> B according to the second modification, the lubricating layer 42 is disposed on the wall surface of the through hole 40 </ b> H of the holding member 40 or the outer peripheral surface of the tip portion of the optical fiber 50.

  The material of the lubricating layer 42 is selected from, for example, solid lubricating materials such as fluororesin, graphite, and molybdenum disulfide. In addition, a liquid lubricant or a powder lubricant may be used for the lubricant layer 42 depending on the application.

  The lubricating layer 42 may cover the surface of the holding member 40 other than the wall surface of the through hole 40H. Further, the lubricating layer 42 may cover the surface other than the tip of the optical fiber 50, or may cover the through hole 40H and the optical fiber 50.

  In the case where there is a firing step / heating step in the step of providing the lubricating layer 42, the holding member 40 may be manufactured by performing processing after the lubricating layer 42 is provided on the member having the through hole 40H. Further, a hollow cylindrical solid lubricant may be inserted into the through hole 40H, or the optical fiber 50 may be inserted through the hollow cylindrical solid lubricant.

  In the optical transmission module 1B, the friction coefficient μ can be set to 0.5 or less regardless of the materials of the optical fiber 50 and the holding member 40.

  In the optical transmission module 1B, it is not difficult to reduce the friction coefficient μ between the optical fiber 50 and the holding member 40 to 0.2 or less by the lubricating layer 42, and the stress applied to the optical fiber 50 is reduced. It can be reduced more.

<Modification 3>
As already described, the length D of the through hole 40H is set according to the force (deformation amount) applied to the optical fiber 50. However, depending on the specifications of the endoscope, the length of the rigid tip portion 81 is limited, and a sufficient length D may not be ensured. In addition, unexpected stress may be applied. When the optical fiber 50 is removed from the through hole 40H, the optical signal cannot be transmitted.

  As illustrated in FIG. 5, the optical transmission module 1 </ b> C according to the third modification includes a first locking member 52 that prevents the optical fiber 50 from being removed from the through hole 40 </ b> H.

  The first locking member 52 has a string-like member 52A and a fixing member 52B. One end of the string-like member 52A is fixed to the holding member 40A, and the other end is fixed to the fixing member 52B. The fixing member 52B is fixed to the optical fiber 50.

  The length of the string-like member 52A is set so as not to be removed from the through hole 40H even if the optical fiber 50 is pulled backward.

  The optical transmission module 1 </ b> C can continuously transmit an optical signal even when an unexpected tensile stress is applied to the optical fiber 50.

<Modification 4>
As already described, the length D of the through hole 40H is set according to the force (deformation amount) applied to the optical fiber 50. However, unexpected stress may be applied. When the distal end surface 50SA of the optical fiber 50 and the optical element 10 come into contact with each other, the light emitting unit 11 and the optical fiber 50 are damaged and an optical signal cannot be transmitted.

  As illustrated in FIG. 6, the optical transmission module 1 </ b> D of Modification 4 includes a second locking member 54 that prevents contact between the optical fiber 50 and the optical element 10.

  The second locking member 54 is a donut-shaped member disposed in the opening of the hole of the first main surface 20SA of the wiring board 20. Since there is the second locking member 54 whose inner diameter is smaller than the outer diameter of the optical fiber 50, there is no possibility that the optical fiber 50 and the optical element 10 will contact each other.

  Note that the first locking member may have the function of the second locking member. For example, the contact between the optical fiber 50 and the optical element 10 can be prevented by the fixing member 52B shown in FIG. 5 coming into contact with the holding member 40A.

Second Embodiment
Since the endoscope 2 according to the second embodiment includes the light transmission modules 1, 1 </ b> A to 1 </ b> D that have already been described, the same components are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 7, the endoscope 2 of this embodiment includes an insertion portion 80, an operation portion 84 disposed on the proximal end side of the insertion portion 80, and a universal cord extending from the operation portion 84. 92 is an electronic endoscope including a connector 93 disposed on the base end side of the universal cord 92.

  In the insertion portion 80, a hard tip portion 81, a bending portion 82 for changing the direction of the hard tip portion 81, and a flexible elongated soft portion 83 are sequentially connected.

  The rigid tip 81 is an E / O module that converts an image pickup optical unit (not shown), an image pickup device 90 (FIG. 4), and an image pickup signal (electric signal) from the image pickup device 90 (FIG. 4) into an optical signal. An optical transmission module 1 is provided. The image sensor 90 is a CMOS (Complementary Metal Oxide Semiconductor) image sensor, a CCD (Charge Coupled Device), or the like.

  As already described, the optical transmission module 1 includes the optical element 10, the wiring board 20, the holding member 40, and the optical fiber 50 in which the tip portion is inserted into the through hole 40 </ b> H of the holding member 40.

  The operation unit 84 is provided with an angle knob 85 for operating the bending portion 82 and an O / E module 91 which is an optical transmission module for converting an optical signal into an electric signal. The connector 93 has an electrical connector portion 94 that is connected to a processor (not shown), and a light guide connection portion 95 that is connected to a light source. The light guide connection portion 95 is connected to an optical fiber bundle that guides illumination light to the hard tip portion 81. In the connector 93, the electrical connector portion 94 and the light guide connecting portion 95 may be integrated.

  In the endoscope 2, the imaging signal is converted into an optical signal by the optical transmission module 1 of the rigid distal end portion 81 and transmitted to the operation unit 84 via the optical fiber 50 inserted through the insertion unit 80. Then, the optical signal is converted again into an electrical signal by the O / E module 91 provided in the operation unit 84 and transmitted to the electrical connector unit 94 via the metal wiring 50M through which the universal cord 92 is inserted. That is, a signal is transmitted through the thin optical fiber 50 in the thin insertion portion 80, and the metal wire 50M thicker than the optical fiber 50 is inserted in the universal cord 92 that is not inserted into the body and has a small outer diameter restriction. Is transmitted through.

  In the case where the O / E module 91 is disposed in the connector portion 94, the universal cord 92 may be inserted through the optical fiber 50 to the electrical connector portion 94. When the O / E module 91 is disposed in the processor, the optical fiber 50 may be inserted up to the connector 93.

  Stress may be applied to the optical fiber 50 inserted through the insertion portion 80 of the endoscope 2 when the insertion portion 80 is deformed. There is a possibility that the optical fiber 50 may be subjected to a large stress, in particular, due to the bending operation of the bending portion 82.

  As shown in FIG. 8, the path length L through which the optical fiber 50 is inserted when the bending portion 82 is in the straight state (A) is L0. On the other hand, when the bending portion 82 is bent in the (B) direction, the path length L is shortened, so that there is a possibility that compressive stress is applied to the optical fiber 50. On the other hand, when the bending portion 82 is bent in the (C) direction, the path length L becomes long, and thus there is a possibility that tensile stress is applied to the optical fiber 50.

  Here, as shown in FIG. 9, the case where the bending portion 82 is bent in the (B) direction and the bending angle is an angle φ will be described. As a premise, even if the scope is curved, the length of the scope center (x = 0) remains L0. When the insertion path of the optical fiber 50 is separated from the center line O of the bending portion 82 by the shift amount x, the path length L decreases from L0 to L1.

L1 = L0−ΔL (Formula 1)
However, ΔL = 2πx (φ / 360)

  That is, ΔL depends on the shift amount x and the bending angle φ. For example, when the deviation amount x = 5 mm and the bending angle φ = 180 degrees, ΔL≈15 mm. The maximum bending angle φmax of the bending portion 82 varies depending on the specification, but may be 360 degrees or more.

  Conversely, when the bending portion 82 is bent in the (C) direction, the path length L increases by ΔL.

  For this reason, the length D of the holding member 40, that is, the length D of the through hole 40H described in FIG. 1 and the like is set to 2 × ΔLmax or more based on the shift amount x and the maximum bending angle φmax. . ΔLmax is the amount of deformation at the maximum bending angle φmax. The length D is preferably 5 mm + ΔLmax or less so as not to increase the length of the hard tip portion 81.

  As shown in FIG. 1, the length of the optical fiber 50 of the optical transmission module 1 is such that when the bending portion 82 is in a straight state (A), the distal end surface 50SA of the optical fiber 50 is It is designed to be positioned approximately at the center of the through hole 40H.

  In the endoscope 2, the stress is released because the optical fiber 50 moves inside the through hole 40 </ b> H of the holding member 40 with the deformation of the bending portion 82. In the endoscope 2, since a large stress is not applied to the optical fiber 50, there is no possibility that the optical fiber 50 is broken or broken. For this reason, the endoscope 2 can transmit an optical signal stably.

  The endoscope 2 according to the embodiment can use any of the light transmission modules 1A to 1D according to the modified example instead of the light transmission module 1 according to the first embodiment, and further, the light transmission module 1A according to the modified example. A 1D configuration may be combined.

  Below, an example of the endoscope of the embodiment is shown.

An insertion portion 80 in which a hard tip portion 81, a bending portion 82 for changing the direction of the hard tip portion 81, and a flexible soft portion 83 are connected, and light inserted through the inside of the insertion portion 80 An optical fiber 50 for transmitting a signal,
In the rigid tip 81,
An image sensor 90;
An optical element 10 having a light emitting unit 11 that converts an electrical signal output from the imaging element 90 into an optical signal;
A holding member 40 having a through hole 40H and disposed so that the light emitting portion 11 and the through hole 40H face each other;
It has a first main surface 20SA and a second main surface 20SB, the optical element 10 and the first main surface 20SA are joined, the holding member 40 and the second main surface 20SB are joined, A wiring board 20 having a hole at a position facing the through hole 40H and the light emitting unit 11 is disposed,
The optical fiber 50 is inserted into the through hole 40H of the holding member 40, and moves inside the through hole 40H as the bending portion 82 is deformed.
A lubricating layer 42 is disposed on at least one of the tip portion of the optical fiber 50 or the through hole 40H,
A first locking member 52 for preventing the optical fiber 50 from being pulled out of the through hole 40H;
An endoscope comprising a second locking member 54 that prevents contact between the optical fiber 50 and the optical element 10.

  That is, 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-1D ... Optical transmission module 2 ... Endoscope 10 ... Optical element 10A ... Optical element 12 ... Electrode 20 ... Wiring board 20H ... Hole 21 ... Electrode pad 30 ... Adhesive layer 40 ... Holding member 40H ... Through hole 42 ... Lubricating layer 50 ... Optical fiber 52 ... First locking member 54 ... Second engagement Stop member 80 ... insertion part 81 ... hard tip part 82 ... bending part 83 ... soft part 84 ... operation part 90 ... imaging element 91 ... O / E module

Claims (14)

An insertion portion in which a hard tip portion, a bending portion for changing the direction of the hard tip portion, and a flexible soft portion are connected,
An optical fiber that transmits an optical signal inserted through the insertion portion, and
In the hard tip,
An image sensor;
An optical element having a light emitting unit that converts an electrical signal output by the imaging element into the optical signal;
A holding member having a through-hole and disposed so that the light-emitting portion and the through-hole face each other;
A first main surface and a second main surface; the optical element and the first main surface are bonded; the holding member and the second main surface are bonded; And a wiring board having a hole at a position facing the hole and the light emitting part,
The optical fiber has a distal end inserted into the through hole of the holding member, and moves inside the through hole in accordance with the deformation of the curved portion,
A lubricating layer is disposed at least at one of the tip of the optical fiber or the through hole,
A first locking member for preventing the optical fiber from being removed from the through hole;
An endoscope comprising: a second locking member that prevents contact between the optical fiber and the optical element. An insertion portion in which a hard tip portion, a bending portion for changing the direction of the hard tip portion, and a flexible soft portion are connected,
An optical fiber that transmits an optical signal inserted through the insertion portion, and
In the hard tip,
An image sensor;
An optical element having a light emitting unit that converts an electrical signal output by the imaging element into an optical signal;
A holding member having a through-hole and disposed so that the light-emitting portion and the through-hole face each other; and
An endoscope, wherein a tip portion of the optical fiber is inserted into the through hole of the holding member, and the optical fiber moves freely within the through hole.   The endoscope according to claim 2, wherein a tip of the optical fiber is positioned at a central portion of the through hole when the bending portion is in a straight state.   A first main surface and a second main surface; the optical element and the first main surface are bonded; the holding member and the second main surface are bonded; The endoscope according to claim 3, further comprising a wiring board having a hole at a position facing the hole and the light emitting unit.   The endoscope according to claim 3, wherein a coefficient of friction μ between the optical fiber and the through hole is 0.5 or less.   The endoscope according to claim 5, wherein a lubricating layer is disposed on at least one of a tip portion of the optical fiber and the through hole.   The endoscope according to claim 3, further comprising a first locking member that prevents the optical fiber from being pulled out of the through hole.   The endoscope according to claim 3, further comprising a second locking member that prevents contact between the optical fiber and the optical element. An optical element having a light emitting unit for converting an electrical signal into an optical signal;
A holding member having a through-hole and disposed so that the light-emitting portion and the through-hole face each other;
An optical fiber for transmitting the optical signal,
The optical transmission module is characterized in that a tip end portion is inserted into the through hole of the holding member, and the optical fiber moves freely in the through hole.   A first main surface and a second main surface; the optical element and the first main surface are bonded; the holding member and the second main surface are bonded; The optical transmission module according to claim 9, further comprising a wiring board having a hole at a position facing the hole.   The optical transmission module according to claim 9, wherein a friction coefficient μ between the optical fiber and the through hole is 0.5 or less.   The optical transmission module according to claim 11, wherein a lubricating layer is disposed on at least one of a tip portion of the optical fiber and the through hole.   The optical transmission module according to claim 9, further comprising a first locking member that prevents the optical fiber from being pulled out of the through hole.   The optical transmission module according to claim 9, further comprising a second locking member that prevents contact between the optical fiber and the optical element.

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