Optical inspection device and optical fiber structure

Abstract

Provided is an optical inspection device that can be inserted into a tubular body and that can improve the SN ratio when receiving reflected light from an inspection subject. An optical inspection device (1) is provided with a light source (23), a light-emitting optical fiber (2), a light-receiving optical fiber (3), and a light detection unit (33), the light-emitting optical fiber (2) having a first light guide unit (22) that transmits light emitted from the light source (23), and a first light-emitting unit (21) that irradiates the light transmitted by the first light guide unit (22) as irradiation light to an object to be inspected. The light-receiving optical fiber (3) has a first light-receiving unit (31) that receives reflected light obtained by reflecting the irradiation light by the object to be detected, and a second light-guiding unit (32) that transmits the reflected light received by the first light-receiving unit (31), and the light-detecting unit (33) detects the reflected light propagating through the second light-guiding unit (32). The optical fiber structure (10) is formed in such a manner that the first light-emitting section (21) and the first light-receiving section (31) are separated from each other with a light-shielding member (4) comprising a non-translucent material interposed therebetween.

Description

Technical Field

[0001] This invention relates to an optical inspection device and an optical fiber structure. Background Technology

[0002] Optical inspection devices that illuminate a target object with light and detect its reflected light are used in various fields, including the medical field. They are configured to transmit light emitted from a light source to a light-emitting unit via an optical fiber, illuminate the target object from the light-emitting unit, and transmit the reflected light from the target object received by the light-receiving unit to a light-detecting unit via an optical fiber. The light detected by the light-detecting unit is then processed to inspect the target object.

[0003] For example, Patent Document 1 describes a laser flowmeter comprising a flowmeter body, an irradiation fiber and a light-receiving fiber connected to the flowmeter body, and a probe with the front ends of the irradiation fiber and the light-receiving fiber fixed in parallel. Laser light is irradiated from the flowmeter body through the irradiation fiber into biological tissue, and scattered light within the biological tissue is transmitted as blood flow information back to the flowmeter body via the light-receiving fiber. The fiber probe used in this laser flowmeter is configured to have a reflective fixing plate with fixing units for fixing to the biological tissue. The irradiation fiber and the light-receiving fiber are fixed in parallel on the reflective surface of the reflective fixing plate to form the probe, so that the laser light output from the irradiation fiber and the scattered light within the biological tissue are reflected on the reflective surface of the reflective fixing plate.

[0004] Furthermore, Patent Document 2 discloses a medical system comprising: a catheter including a distal component for performing medical surgery on tissue within a cavity of a patient's organ, the distal component including an optical fiber configured to guide illumination light (transmitted light) to interact with the tissue in the cavity and to guide reflected light (return light) after interaction with the tissue; a light source configured to generate illumination light; a detector configured to measure reflected light; a circulator configured to couple illumination light from the light source to the optical fiber and reflected light from the optical fiber to the detector; and a processor configured to identify contact between the distal component and the tissue based on the reflected light measured by the detector and to show the identified contact to the user.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 10-118039 Patent Document 2: Japanese Patent Application Publication No. 2022-126610 Summary of the Invention

[0006] The problem that the invention aims to solve In surgeries and other procedures, when temporarily blocking blood flow within a blood vessel, a balloon catheter is inserted into the vessel to inflate and seal the flow. Additionally, in non-medical fields, such as water supply systems, a balloon is inserted into the pipe to inflate and stop the flow of water (balloon-type water-stopping method). In these methods, it is considered to place light-emitting and light-receiving optical fibers inside the balloon catheter and balloon, and to detect the closure of the blood vessel or pipe by utilizing the difference in light reflectivity between the vessel wall and blood, or the difference in light reflectivity caused by the presence or absence of water between the vessel wall and the balloon.

[0007] However, the laser flowmeter described in Patent Document 1 is a laser flowmeter that measures blood flow by fixing a reflective fixing plate to the surface of biological tissues such as the body surface, and does not specifically envision being inserted into a thin tube such as a blood vessel.

[0008] Furthermore, the medical system described in Patent Document 2 consists of a single optical fiber, which uses a circulator to separate the illumination light emitted from the light source from the reflected light from the object being detected. As with this medical system, when only one optical fiber is used to transmit the illumination light and reflected light, reflected light (hereinafter referred to as Fresnel reflected light) is generated due to Fresnel reflection at the fiber tip. This Fresnel reflected light becomes significantly noisier than the reflected light reflected from the object being detected, thus resulting in a reduced signal-to-noise ratio (SNR).

[0009] The purpose of this invention is to provide an optical inspection device and an optical fiber structure that, for example, can be inserted into a tubular body, especially a thin tubular body such as a blood vessel, when the object to be inspected is a tubular body, and can prevent noise caused by Fresnel reflection light and improve the signal-to-noise ratio when receiving reflected light reflected from the object to be inspected.

[0010] Methods for solving problems The inventors of this application discovered the following, thereby completing the present invention: using an optical fiber for transmitting light emitted from a light source and an optical fiber for transmitting reflected light received from a detection object (inspection object), and fixing the first light-emitting part of the optical fiber for transmitting light emitted from the light source and the first light-receiving part of the optical fiber for receiving light in a parallel configuration separated by a light-shielding member containing a non-transparent material, preferably configured such that the light-shielding member has a size equal to or greater than the length and outer diameter of the first light-receiving part, thereby the first light-receiving part of the optical fiber for receiving light will not directly receive the illumination light emitted from the first light-emitting part of the optical fiber for transmitting light, but can effectively receive the reflected light, thereby improving the SN ratio when receiving reflected light.

[0011] To achieve the above objectives, the main components of the present invention are as follows.

[0012] (1) An optical inspection device comprising: a light source; at least one light-emitting optical fiber having a first light guide portion for transmitting light emitted from the light source and a first light-emitting portion for irradiating a test object with light transmitted in the first light guide portion as irradiation light; at least one light-receiving optical fiber having a first light-receiving portion for receiving reflected light after the irradiation light emitted from the first light-emitting portion is reflected by the test object and a second light guide portion for transmitting reflected light received by the first light-receiving portion; and a light detection unit for detecting reflected light propagating in the second light guide portion of the light-receiving optical fiber, wherein the light-emitting optical fiber and the light-receiving optical fiber are configured to form an optical fiber structure by means of a light-shielding member comprising a non-transparent material separating the first light-emitting portion and the first light-receiving portion.

[0013] (2) The optical inspection device according to (1) above, wherein the light-shielding member has a size equal to or greater than the length and outer diameter of the first light-receiving part.

[0014] (3) The optical inspection device according to (1) or (2) above, wherein the irradiation light is emitted from the side of the first light-emitting part.

[0015] (4) An optical inspection apparatus according to any one of (1) to (3) above, wherein the length of the first light-receiving portion of the light-receiving optical fiber is longer than the length of the first light-emitting portion of the light-emitting optical fiber.

[0016] (5) An optical inspection apparatus according to any one of (1) to (4) above, wherein the front end of the first light-receiving part of the light-receiving optical fiber is located at a position that protrudes further forward than the front end of the first light-emitting part of the light-emitting optical fiber.

[0017] (6) The optical inspection device according to any one of (1) to (5) above, wherein the light-emitting optical fiber and the light-receiving optical fiber are made of quartz optical fiber or plastic optical fiber.

[0018] (7) An optical fiber structure comprising: at least one light-emitting optical fiber having a first light guide portion for transmitting light emitted from a light source and a first light-emitting portion for irradiating a detection object with light transmitted in the first light guide portion as irradiation light; and at least one light-receiving optical fiber having a first light-receiving portion for receiving reflected light after the irradiation light emitted from the first light-emitting portion is reflected by the detection object and a second light guide portion for transmitting reflected light received by the first light-receiving portion, wherein the light-emitting optical fiber and the light-receiving optical fiber are configured to be isolated from the first light-emitting portion and the first light-receiving portion by a light-shielding member comprising a non-transparent material to form an optical fiber structure.

[0019] (8) The optical fiber structure according to (7) above, wherein the light-shielding component has a size equal to or greater than the length and outer diameter of the first light-receiving part.

[0020] The effects of the invention According to the present invention, an optical inspection device and an optical fiber structure can be provided, for example, when the object to be inspected is a tubular body, especially a thin tubular body such as a blood vessel, it can be inserted into such a tubular body, and can prevent noise caused by Fresnel reflection light and improve the SN ratio when receiving reflected light reflected from the object to be inspected. Attached Figure Description

[0021] Figure 1 This is a top view schematically showing the configuration of the optical inspection device and the fiber optic structure of the first embodiment.

[0022] Figure 2 This diagram shows the positional relationship between the optical fiber structure and the tube when the optical fiber structure of the optical inspection device of the first embodiment is inserted into the tube that is being inspected. Figure 2 (a) is an enlarged longitudinal section view of the main part of the optical fiber structure. Figure 2 (b) is in Figure 2 The cross-sectional view of (a) cut along line I-I' shows the light path of the illumination light emitted from the first light-emitting part and the reflected light from the tube received by the first light-receiving part.

[0023] Figure 3 This is a top view showing the structure of the optical fiber structure in the second embodiment.

[0024] Figure 4 This is a top view showing the structure of the optical fiber structure in other embodiments.

[0025] Figure 5 This diagram illustrates the positional relationship between the optical fiber structure and the tube when the optical fiber structure of another embodiment of the optical inspection device is inserted into the tube being inspected. Figure 5 (a) is an enlarged longitudinal section view of the main part of the optical fiber structure. Figure 5 (b) is in Figure 5 The cross-sectional view of (a) cut along line II-II' shows the light path of the irradiated light emitted from the first light-emitting part and the reflected light from the tube received by the first light-receiving part.

[0026] Figure 6 This is a cross-sectional view showing the arrangement of the light-emitting optical fiber, the light-receiving optical fiber, and the light-shielding component that constitute the optical inspection device and optical fiber structure of the third embodiment.

[0027] Figure 7This is a cross-sectional view showing the arrangement of the light-emitting optical fiber, the light-receiving optical fiber, and the light-shielding component in the optical inspection device and optical fiber structure constituting the fourth embodiment.

[0028] Figure 8 This is a longitudinal cross-sectional view of the first light-emitting section of an optical fiber used for light emission in various modes. Figure 8 (a) indicates the case where the first light-emitting part is formed by creating a rough surface on the cladding of the light-emitting optical fiber. Figure 8 (b) indicates the case where the first light-emitting part is formed by removing the entire cladding of the light-emitting optical fiber radially and forming a light-diffusing resin layer on the surface of the removed cladding. Figure 8 (c) indicates the case where the first light-emitting part is formed by removing a portion of the cladding of the light-emitting optical fiber in the radial direction and forming a light-diffusing resin layer on the surface of the removed cladding. Figure 8 (d) indicates the case where a coreless fiber or an optical diffusion fiber is fused to the front end of the optical fiber used for light emission.

[0029] Figure 9 This is a longitudinal cross-sectional view of the first light-emitting section of an optical fiber used for light emission in various modes. Figure 9 (a) indicates the case where the core and the leading edge of the cladding of the light-emitting optical fiber are cut into a conical shape to form the first light-emitting part. Figure 9 (b) indicates the case where the core and cladding of the light-emitting optical fiber are cut at an angle to form the first light-emitting part.

[0030] Figure 10 This is a longitudinal cross-sectional view of the first light-receiving section of an optical fiber used for receiving light in various ways. Figure 10 (a) indicates the case where the first light-receiving part is formed by creating a rough surface on the cladding of the light-receiving optical fiber. Figure 10 (b) indicates the case where the core of the light-receiving fiber is retained, and the first light-receiving part is formed by removing the cladding.

[0031] Figure 11 This is a longitudinal cross-sectional view of the first light-receiving section of an optical fiber used for receiving light in various ways. Figure 11 (a) indicates the case where the first light-receiving part is formed by creating a rough surface on the cladding of the light-receiving optical fiber. Figure 11 (b) indicates the case where the first light-receiving part is formed by removing the entire cladding of the light-receiving optical fiber radially and forming a light-diffusing resin layer on the surface of the removed cladding. Figure 11 (c) indicates the case where a portion of the cladding of the light-receiving optical fiber is removed radially, and a light-diffusing resin layer is formed on the surface of the removed cladding to create the first light-receiving portion. Figure 11 (d) indicates the case where a coreless fiber or an optical diffusion fiber is fused to the front end of the optical fiber used for receiving light. Detailed Implementation

[0032] Next, several embodiments of the optical inspection device and fiber optic structure of the present invention will be described below.

[0033] <First Implementation> Figure 1 This is a schematic top view illustrating the optical inspection device of the first embodiment. Additionally, Figure 2 This diagram shows the positional relationship between the optical fiber structure and the tube when the optical fiber structure of the optical inspection device of the first embodiment is inserted into the tube that is the object to be inspected. Figure 2 (a) is an enlarged longitudinal section view of the main part of the optical fiber structure. Figure 2 (b) is in Figure 2 The cross-sectional view of (a) cut along line I-I' shows the light path of the illumination light emitted from the first light-emitting part and the reflected light from the tube received by the first light-receiving part.

[0034] like Figure 1 As shown, the optical inspection device 1 includes a light source 23, at least one light-emitting optical fiber 2, at least one light-receiving optical fiber 3, and a light detection unit 33. The light-emitting optical fiber 2 has a first light guide section 22 for transmitting light emitted from the light source 23, and a first light-emitting section 21 for irradiating the object under inspection 6 with light transmitted in the first light guide section 22 as irradiation light Lt. The light-receiving optical fiber 3 has a first light-receiving section 31 for receiving reflected light Lt' after the irradiation light Lt emitted from the first light-emitting section 21 is reflected by the object under inspection 6, and a second light guide section 32 for transmitting the reflected light Lt' received by the first light-receiving section 31. The light detection unit 33 detects the reflected light Lt' propagating in the second light guide section 32 of the light-receiving optical fiber 3. Here, the optical inspection device 1 may also include a display section 34 for displaying a detection value such as the intensity of the reflected light Lt' detected by the light detection unit 33. It should be noted that the display unit 34 may also be configured to not only display the detected value of the intensity of the reflected light Lt', but also to perform a prescribed process on the reflected light Lt' and display the result of the process.

[0035] In addition, such as Figure 2 As shown in (a) and (b), the light-emitting optical fiber 2 and the light-receiving optical fiber 3 are configured to form an optical fiber structure 10, with the first light-emitting part 21 and the first light-receiving part 31 separated by a light-shielding member 4 containing a non-transparent material. At this time, the first light-emitting part 21 and the first light-receiving part 31 are fixedly connected in a side-by-side configuration separated by the light-shielding member 4.

[0036] Therefore, as Figure 2As shown in (a), the first light-emitting part 21 of the light-emitting optical fiber 2 and the first light-receiving part 31 of the light-receiving optical fiber 3 are arranged side by side, separated by a light-shielding member 4, and the light-shielding member 4 has a size equal to or greater than the length P3 and outer diameter D2 of the first light-receiving part 31, thereby... Figure 2 As shown in (b), when the illumination light Lt illuminates the detection object 6, the reflected light Lt' obtained by the detection object 6 after one or more reflections enters the first light-receiving section 31. Furthermore, it is possible to effectively suppress the direct entry of the illumination light Lt emitted from the first light-emitting section 21 into the first light-receiving section 31. Therefore, it is expected to reduce the noise in the detection value of the intensity of the reflected light Lt' entering the first light-receiving section 31 caused by the entry of the illumination light Lt. In addition, by constructing the light-emitting fiber 2 and the light-receiving fiber 3 from different optical fibers, it is expected to prevent noise caused by Fresnel reflection. Moreover, by reducing and preventing these noises, it is expected to improve the signal-to-noise ratio (SN ratio) when receiving the reflected light Lt' reflected from the detection object 6.

[0037] [About the structure of the optical fiber structure] The optical fiber structure 10 includes a light-emitting optical fiber 2 and a light-receiving optical fiber 3, and the light-emitting optical fiber 2 and the light-receiving optical fiber 3 are arranged in a configuration where a first light-emitting part 21 and a first light-receiving part 31 are separated by a light-shielding member 4 containing a non-transparent material, thus forming the optical fiber structure 10. Figure 1 The fiber optic structure 10 shown includes a light-emitting fiber 2, a light-receiving fiber 3, and a light-shielding component 4. By using different fibers to construct the light-emitting fiber 2 and the light-receiving fiber 3, the fiber optic structure 10 is expected to prevent noise on the reflected light Lt' caused by Fresnel reflection.

[0038] (Optical fiber for light emission) The optical fiber 2 for emitting light has a first light guide section 22 for transmitting light emitted from the light source 23, and a first light-emitting section 21 for irradiating the object 6 with the light transmitted in the first light guide section 22 as irradiation light Lt. This allows light emitted from the light source 23 to be transmitted through the first light guide section 22 with minimal loss. Furthermore, by transmitting light from the light source 23 with less loss, it is expected that more light can be emitted as irradiation light Lt from the first light-emitting section 21 onto the inner surface of the tube that becomes the object 6.

[0039] Here, the light-emitting optical fiber 2 is configured to transmit light from the light source 23 in at least the first light guide section 22. As an example of the light-emitting optical fiber 2, it can be described as an optical fiber with a core-cladding structure having a core-cladding structure at its center when viewed in a cross-section perpendicular to the fiber axis direction X. In this case, the first light guide section 22 of the light-emitting optical fiber 2 is preferably composed of an optical fiber whose cladding has not been removed. By using an optical fiber with an unremoved cladding to form the first light guide section 22, it is expected that light from the light source 23 will be transmitted with less loss. On the other hand, the first light-emitting section 21 of the light-emitting optical fiber 2 can be formed in a shape where part or all of the cladding has been removed. By using an optical fiber with a shape where part or all of the cladding has been removed to form the first light-emitting section 21, it is expected that light from the light source 23 emitted from the portion with the removed cladding will be emitted as illumination light Lt. It should be noted that the light-emitting optical fiber 2 is not limited to a fiber shape; it can also be in the form of an optical waveguide formed on a substrate or the like.

[0040] From the viewpoint of reducing the loss of reflected light Lt' by shortening the optical path up to the detection object 6, it is preferable that the first light-emitting part 21 of the light-emitting fiber 2 is configured such that the illumination light Lt emits light approximately perpendicularly to the fiber axis direction X of the light-emitting fiber 2. From this viewpoint, it is preferable that the illumination light Lt emitted from the first light-emitting part 21 is emitted from the side of the first light-emitting part 21.

[0041] In addition, the portion of the first light-emitting part 21 of the light-emitting optical fiber 2 that emits at least illumination light Lt may also be a portion that has undergone at least any of the following processes (a) to (d).

[0042] (a) Surface roughening treatment using hydrofluoric acid, organic solvents, etc. (b) Pattern forming process using lasers (c) Coating the portion of the coating that has been removed with a transparent resin containing light-diffusing substances such as titanium dioxide. (d) Fusion splice the coreless fiber or optically diffused fiber to the front end. Preferably, the portion where the coreless optical fiber or optical diffusion optical fiber is fused together by (d) to the front end is coated with a transparent resin having a high refractive index. In this case, the transparent resin used in the coating process preferably has a higher refractive index than the quartz glass constituting the cladding 27 of the quartz optical fiber, for example, when the light-emitting optical fiber 2 is formed of quartz optical fiber.

[0043] Furthermore, from the viewpoint of ensuring mechanical strength, the portions of the optical fiber 2 that have undergone (a) roughening treatment or (b) patterning treatment can be further coated with transparent resin. The refractive index of the transparent resin used in this case is not particularly limited.

[0044] The material of the light-emitting optical fiber 2 is not particularly limited, but from the viewpoint of easy insertion into a tubular body or the like, which is the object of detection 6, it is preferable to use a quartz optical fiber or a plastic optical fiber. Quartz optical fiber has tensile strength, therefore, by using quartz optical fiber as the light-emitting optical fiber 2, even if the tubular body, which is the object of detection 6, has a small diameter, the light-emitting optical fiber 2 can be inserted deep into the internal space of the tubular body. Furthermore, since plastic optical fiber is flexible, by using plastic optical fiber as the light-emitting optical fiber 2, even if the tubular body, which is the object of detection 6, has a highly curved portion, the light-emitting optical fiber 2 can be inserted into the highly curved portion.

[0045] The outer diameter D1 of the light-emitting optical fiber 2 is preferably set according to the object 6 to be detected by the optical inspection device 1. For example, when the object 6 to be detected is the inner wall of a blood vessel, from the viewpoint of easy installation into a narrow tube such as a balloon catheter inserted into a blood vessel, the outer diameter D1 of the light-emitting optical fiber 2 is preferably 250 μm or less.

[0046] (Optical fiber for receiving light) The light-receiving optical fiber 3 has a first light-receiving section 31 that receives the reflected light Lt' after the illumination light Lt emitted from the first light-emitting section 21 is reflected by the object being inspected 6, and a second light-guiding section 32 that transmits the reflected light Lt' received by the first light-receiving section 31. Therefore, it is expected that the reflected light Lt' from the inner surface 6a, etc., of the tube that is the object being inspected 6 can be received from the first light-receiving section 31, and transmitted in the second light-guiding section 32 with minimal loss, and reflected in the inspection results via the light detection section 33, etc., as described later.

[0047] Here, the light-receiving optical fiber 3 is configured to transmit reflected light Lt' in at least the second light guide section 32. As an example of the light-receiving optical fiber 3, an optical fiber with the same core-cladding structure as the light-emitting optical fiber 2 described above can be used. In this case, the second light guide section 32 of the light-receiving optical fiber 3 is preferably composed of an optical fiber whose cladding has not been removed. By using an optical fiber whose cladding has not been removed to form the second light guide section 32, it is expected that the reflected light Lt' will be transmitted with less loss. On the other hand, the first light-receiving section 31 of the light-receiving optical fiber 3 can be formed in a shape where part or all of the cladding has been removed. By using an optical fiber whose cladding has been partially or completely removed to form the first light-receiving section 31, it is expected that the reflected light Lt' will be received from the portion where the cladding has been removed.

[0048] The first light-receiving part 31 of the light-receiving optical fiber 3 may also be a light-receiving part whose surface, at least the part receiving the reflected light Lt', has undergone roughening treatment using hydrofluoric acid, organic solvents, or the like. It should be noted that the light-receiving optical fiber 3 is not limited to an optical fiber in the shape of a fiber, and may also be an optical fiber in the form of an optical waveguide formed on a substrate or the like.

[0049] In addition, the portion of the first light-receiving section 31 of the light-receiving optical fiber 3 that receives at least reflected light Lt' may also be a portion that has undergone at least any of the following processes (a) to (d).

[0050] (a) Surface roughening treatment using hydrofluoric acid, organic solvents, etc. (b) Pattern forming process using lasers (c) Coating the portion of the coating that has been removed with a transparent resin containing light-diffusing substances such as titanium dioxide. (d) Fusion splice the coreless fiber or optically diffused fiber to the front end. Preferably, the portion where a coreless optical fiber or an optical diffusion fiber is fused together by fusion splicing to the front end via (d) is coated with a transparent resin having a high refractive index. In this case, the transparent resin used in the coating process preferably has a higher refractive index than the quartz glass constituting the cladding 37 of the quartz optical fiber, for example, when the light-receiving optical fiber 3 is formed of a quartz optical fiber.

[0051] Furthermore, from the viewpoint of ensuring mechanical strength, the portions of the optical fiber 3 used for receiving light that have undergone (a) roughening treatment or (b) patterning treatment can be further coated with transparent resin. The refractive index of the transparent resin used in this case is not particularly limited.

[0052] The material of the light-receiving optical fiber 3 is not particularly limited, but from the viewpoint of easy insertion into a tubular body or the like, which is the object of detection 6, it is preferable to make it from quartz optical fiber or plastic optical fiber. Quartz optical fiber has tensile strength, so by using quartz optical fiber as the light-receiving optical fiber 3, even if the tubular body, which is the object of detection 6, has a small diameter, the light-receiving optical fiber 3 can be inserted deep into the internal space of the tubular body. Furthermore, since plastic optical fiber is flexible, by using plastic optical fiber as the light-receiving optical fiber 3, even if the tubular body, which is the object of detection 6, has a highly curved portion, the light-receiving optical fiber 3 can be inserted into the highly curved portion. Here, when the light-emitting optical fiber 2 is made of quartz optical fiber, it is preferable that the light-receiving optical fiber 3 is made of plastic optical fiber. Furthermore, when the light-emitting optical fiber 2 is made of plastic optical fiber, it is preferable that the light-receiving optical fiber 3 is made of quartz optical fiber. Thus, by using different materials to construct the light-emitting optical fiber 2 and the light-receiving optical fiber 3, combining the high tensile strength of quartz optical fiber and the high flexibility of plastic optical fiber, it is possible to adjust the tension and flexibility when a lateral force is applied to the optical fiber structure 10. Furthermore, by adjusting the tension and flexibility when applying lateral force to the fiber optic structure 10, it is expected that the installation of the fiber optic structure 10 into a narrow tube, particularly a balloon catheter or similar device inserted into a blood vessel, will become easier.

[0053] exist Figure 1In the optical examination device 1 shown, the length P3 of the first light-receiving portion 31 of the light-receiving optical fiber 3 is configured to be equal to the length P2 of the first light-emitting portion 21 of the light-emitting optical fiber 2. In particular, in the optical examination device 1 in which the optical fiber structure 10 is inserted into a blood vessel, the length P2 of the first light-emitting portion 21 and the length P3 of the first light-receiving portion 31 can both be set to the same length within the range of 5 mm to 50 mm, and as an example, it can be set to 30 mm.

[0054] The outer diameter D2 of the light-receiving optical fiber 3 is preferably set according to the inspection object 6 of the optical inspection device 1, similar to that of the light-emitting optical fiber 2. For example, from the viewpoint of easily installing the optical fiber structure 10 in a narrow-diameter tube, the outer diameter D2 of the light-receiving optical fiber 3 is preferably 250 μm or less. Furthermore, in Figure 1 In the optical inspection device 1 shown, the outer diameter D2 of the light-receiving optical fiber 3 is configured to be the same as the outer diameter D1 of the light-emitting optical fiber 2.

[0055] From the viewpoint that the reflected light Lt', which illuminates the first light-receiving section 31 from a wider direction, propagates to the light-detecting section 33, thereby increasing the amount of light received in the light-detecting section 33, the light-receiving optical fiber 3 is preferably an optical fiber with a high numerical aperture. As an example, the light-receiving optical fiber 3 may also be an optical fiber with a higher numerical aperture than the light-emitting optical fiber 2.

[0056] (Light-shielding components) The light-shielding component 4, comprising a non-transparent material, is disposed between the first light-emitting portion 21 of the light-emitting optical fiber 2 and the first light-receiving portion 31 of the light-receiving optical fiber 3, which are arranged side-by-side. At this time, the light-emitting optical fiber 2 and the light-receiving optical fiber 3 are configured such that the first light-emitting portion 21 and the first light-receiving portion 31 are separated by the light-shielding component 4 containing the non-transparent material, thus forming the optical fiber structure 10. In this way, by arranging the light-shielding component 4 such that the first light-emitting portion 21 and the first light-receiving portion 31 are separated by the light-shielding component 4, and fixing the first light-emitting portion 21 and the first light-receiving portion 31 in a side-by-side configuration, the light-shielding component 4 effectively prevents the illumination light Lt emitted from the first light-emitting portion 21 from directly entering the first light-receiving portion 31. Furthermore, through the fixed connection of the aforementioned component, the optical fiber structure 10 can be easily installed into the tube and inserted into the detection object 6 without changing the positional relationship between the light-shielding component 4 and the first light-emitting portion 21 and the first light-receiving portion 31.

[0057] Here, it is preferable that the light-shielding member 4 is configured to have dimensions equal to or greater than the length and outer diameter of the first light-receiving part 31. More specifically, such as Figure 2As shown in (a), preferably, the length dimension P1 of the light-shielding member 4 along the fiber axis direction X of the light-receiving fiber 3 is the same as, or larger than, the length dimension P3 of the first light-receiving portion 31 along the fiber axis direction X of the light-receiving fiber 3. Furthermore, as... Figure 2 As shown in (b), when viewed from a cross-section perpendicular to the fiber axis direction X of the light-receiving fiber 3, the width W of the light-shielding member 4 is preferably the same as or larger than the outer diameter D2 of the light-receiving fiber 3. By configuring the light-shielding member 4 in this way, when illumination light Lt is irradiated onto the detection object 6, the light directly from the first light-emitting part 21 toward the first light-receiving part 31 is blocked. At this time, the reflected light Lt' obtained by one or more reflections from the detection object 6 enters the first light-receiving part 31, effectively suppressing the direct entry of illumination light Lt emitted from the first light-emitting part 21 into the first light-receiving part 31, thereby reducing the noise in the detected value of the intensity of the reflected light Lt' caused by the entry of illumination light Lt. Furthermore, by reducing this noise, an increase in the SN ratio of the detection light detected by the light detection unit 33 can be expected.

[0058] The shape of the light-shielding member 4 is not particularly limited as long as it can block the illumination light Lt that directly enters the first light-receiving part 31 from the first light-emitting part 21. Therefore, the shape of the light-shielding member 4 can be cylindrical, prism-shaped, plate-shaped, etc. In particular, when the shape of the light-shielding member 4 is plate-shaped, the surface of the light-shielding member 4 can be flat or at least partially curved. On the other hand, when viewed in a cross section perpendicular to the fiber axis direction X of the light-receiving fiber 3, the shape of the light-shielding member 4 can be as follows: Figure 2 (b) shows a rectangle. It should be noted that in this specification, the same direction X is used to represent the fiber axis direction of the light-emitting fiber 2 and the fiber axis direction of the light-receiving fiber 3, but these fiber axis directions may be different.

[0059] The material of the light-shielding component 4 can be a material that blocks the transmission of the irradiating light Lt. In this case, the light-shielding component 4 can block the transmission of the irradiating light Lt either by reflecting it or by absorbing it. Here, metals and resins can be used as materials for the light-shielding component 4 to block the transmission of the irradiating light Lt, and a structure in which at least the surface portion of the light-shielding component 4 is made of metal or resin can be adopted. Therefore, resin can be coated onto the surface portion of a transparent material such as an optical fiber, or metal plating can be applied.

[0060] The fixed connection between the light-shielding component 4 and the first light-emitting part 21 and the first light-receiving part 31 is preferably made in a manner that does not obstruct the light emission from the first light-emitting part 21 and the light reception from the first light-receiving part 31. As a means of fixing the above-mentioned components, in addition to bonding with adhesive, methods such as fixing the vicinity of the first light-emitting part 21 and the first light-receiving part 31 with heat-shrink tubing or similar tubes, or riveting with rings or similar means can also be used to fix the vicinity of the first light-emitting part 21 and the first light-receiving part 31. Furthermore, the fixed connection between the light-shielding component 4 and the first light-emitting part 21 and the first light-receiving part 31 can be made to a part of the area having the light-shielding component 4, or it can be made to the entire area.

[0061] It should be noted that, from the viewpoint of making it easier to install the optical fiber structure 10 into the tube and insert it into the object to be detected 6, it may also have a fixing part 5 that fixes the portion of the light-emitting optical fiber 2 and the light-receiving optical fiber 3 that are not provided with the light-shielding component 4.

[0062] [Regarding the structure of optical inspection devices] like Figure 1 As shown, the optical inspection device 1 includes at least a light source 23, a light-emitting optical fiber 2, a light-receiving optical fiber 3, and a light detection unit 33. The light-emitting optical fiber 2 and the light-receiving optical fiber 3 are arranged in a configuration where the first light-emitting unit 21 and the first light-receiving unit 31 are separated by a light-shielding member 4 containing a non-transparent material, forming an optical fiber structure 10. That is, in addition to the structure of the optical fiber structure 10 described above, the optical inspection device 1 also includes at least a light source 23 and a light detection unit 33.

[0063] In this context, light source 23 is the source of the illuminating light Lt. The light emitted from light source 23 can be light containing a single wavelength component, such as laser light, or light containing multiple wavelength components.

[0064] The wavelength of the light emitted from the light source 23 is preferably selected from wavelengths that can propagate through the light-emitting optical fiber 2 and the light-receiving optical fiber 3, depending on the material of the object being detected 6 and the medium located between the first light-emitting part 21 and the object being detected 6. For example, in the case of inserting a balloon catheter with an internally configured optical fiber structure 10 into a blood vessel to inflate the balloon and thereby close the blood flow, the wavelength of the light emitted from the light source 23 is preferably a wavelength that is more absorbed by blood, i.e., a wavelength in the visible region (wavelengths of 400 nm to 700 nm).

[0065] In addition, the light emitted from the light source 23 can be a continuous wave that emits light through CW oscillation, or a pulse wave that emits light through pulse oscillation.

[0066] The light detection unit 33 detects the reflected light Lt' propagating in the second light guide section 32 of the light-receiving optical fiber 3. The light detection unit 33, for example, is composed of a light sensor, which measures the intensity of the reflected light Lt' and reads out the electrical signal corresponding to that intensity. From the viewpoint of being able to detect the intensity of the reflected light Lt' for each wavelength component, multiple light detection units 33 can be provided. In this case, the light detection unit 33 can also be configured to include multiple light sensors corresponding to each wavelength component.

[0067] Display unit 34 is a part that displays the detected value of the intensity of the reflected light Lt' detected by light detection unit 33. Display unit 34 is configured to display the detected value of the intensity of the received light to the measurer based on the electrical signal based on light detection unit 33. Here, in the case where there are multiple light detection units 33, multiple display units 34 may also be provided for each light detection unit 33.

[0068] It should be noted that the optical inspection device 1 may also include a light detection unit and a display unit (not shown) at the light branch point from the light source 23 on the light source side of the light-emitting fiber 2. Therefore, by detecting the returned light from the light-emitting fiber 2, the amount of loss in the light-emitting fiber 2 and the light-receiving fiber 3 can be predicted. Furthermore, by predicting this amount of loss, an improvement in the inspection accuracy based on the optical inspection device 1 can be expected.

[0069] [Applications of optical inspection devices and fiber optic structures] The optical inspection device 1 and the fiber optic structure 10 can be widely used for inspection by detecting the reflected light Lt' reflected by the object 6 when irradiating the object 6 with irradiation light Lt from the first light receiving part 31.

[0070] As one example, it can be used for the following purposes: when temporarily blocking blood flow in a blood vessel during surgery, a balloon catheter with an internal fiber optic structure 10 is inserted into the blood vessel and the balloon is inflated to block the blood flow. Thus, based on the difference in light reflectivity between the blood vessel wall and the blood, the presence or absence of blood between the blood vessel wall and the balloon can be detected. Furthermore, by detecting the presence or absence of blood between the blood vessel wall and the balloon, it is expected that while appropriately blocking blood flow in the blood vessel, damage to the blood vessel caused by over-inflation of the balloon can be avoided. In this case, the fiber optic structure 10 can also be inserted into medical catheters.

[0071] In another example, it can be used for temporarily stopping water flow in pipes in water supply projects, etc. This is achieved by inserting an airbag containing an internal fiber optic structure 10 into the pipe, causing the airbag to inflate and thus stopping the water flow. The presence or absence of water between the pipe wall and the airbag can be detected based on the difference in light reflectivity caused by the presence or absence of water between them. Furthermore, by detecting water between the pipe wall and the airbag in this way, it is expected that water flow in the pipe can be appropriately stopped without causing damage to the pipes or the airbag due to excessive inflation of the airbag.

[0072] <Second Implementation Method> Figure 3 This is a top view showing the construction of the optical fiber structure in the second embodiment. It should be noted that... Figure 3 The components shown are in relation to Figure 1 When the components of the optical inspection device 1 and the fiber optic structure 10 shown are the same, the same reference numerals are used.

[0073] exist Figure 1 In the optical inspection device 1 shown, the length P2 of the first light-emitting part 21 of the light-emitting optical fiber 2 is equal to the length P3 of the first light-receiving part 31 of the light-receiving optical fiber 3, but it is not limited to this. For example, such as Figure 3 As shown in the optical inspection device 1A, the length P3 of the first light-receiving section 31A of the light-receiving optical fiber 3A can also be configured such that the length P3 of the first light-emitting section 21A of the light-emitting optical fiber 2A is longer than the length P2 of the first light-emitting section 21A of the light-emitting optical fiber 2A. By configuring the first light-emitting section 21A and the first light-receiving section 31A in this way, reflected light Lt' can be received over a wider range of the light-receiving optical fiber 3A, thereby increasing the amount of light received by the light detection section 33.

[0074] In particular, in the optical inspection device 1A in which the fiber optic structure 10A is inserted into a blood vessel, the length dimension P2 of the first light-emitting part 21A can be in the range of 5 mm to 40 mm, and the length dimension P3 of the first light-receiving part 31A can be in the range of 10 mm to 50 mm. As an example, the length dimension P2 of the first light-emitting part 21A can be set to 20 mm, and the length dimension P3 of the first light-receiving part 31A can be set to 30 mm. Here, from the viewpoint of effectively increasing the reflected light Lt' of the first light-receiving part 31A, it is preferable that the length dimension P3 of the first light-receiving part 31A is in the range of 1.5 times to 4.0 times that of the length dimension P2 of the first light-emitting part 21A.

[0075] exist Figure 3In the optical inspection device 1A, preferably, the front end 3a of the first light-receiving section 31A of the light-receiving optical fiber 3A is located further forward than the front end 2a of the first light-emitting section 21A of the light-emitting optical fiber 2A. Therefore, in the optical fiber structure 10A, the protrusion 15 protruding from the front end 3a of the first light-receiving section 31A can also receive reflected light Lt' from the side where the first light-emitting section 21A is located. Furthermore, by receiving the reflected light Lt' from the side where the first light-emitting section 21A is located through this protrusion 15, the amount of light received by the first light-receiving section 31A can be further increased. From the viewpoint of preventing the illumination light Lt from diffracting from the front end 2a of the first light-emitting part 21A to the first light-receiving part 31A, it is more preferable that the front end 3a of the first light-receiving part 31A of the light-receiving optical fiber 3A is located at a position that protrudes further forward than the front end 4a of the light-shielding member 4, and the front end 4a of the light-shielding member 4 is located at a position that protrudes further forward than the front end 2a of the first light-emitting part 21A of the light-emitting optical fiber 2A.

[0076] In addition, optical inspection devices can also be used as... Figure 4 As shown in the optical inspection device 1A', in the fiber optic structure 10A', the length P3 of the first light-receiving portion 31A' of the light-receiving fiber 3A' is longer than the length P2 of the first light-emitting portion 21A' of the light-emitting fiber 2A'. Therefore, it is expected that the amount of light received in the first light-receiving portion 31A' will be further increased. In this optical inspection device 1A', it is preferable that the light-shielding member 4, disposed between the first light-emitting portion 21A' and the first light-receiving portion 31A', is positioned where light directly from the first light-emitting portion 21A' toward the first light-receiving portion 31A' is blocked. Therefore, it is preferable that the length of the light-shielding member 4 in the optical inspection device 1A' is the same as or longer than the length P2 of the first light-emitting portion 21A'.

[0077] On the other hand, optical inspection devices can also be like Figure 5 As shown in the optical inspection device 1B, the first light-receiving part 31B has a smaller length and outer diameter than the first light-emitting part 21B. More specifically, as... Figure 5 As shown in (a), the optical inspection device 1B can also be configured such that the length P3 of the first light-receiving part 31B of the light-receiving optical fiber 3B is shorter than the length P2 of the first light-emitting part 21B of the light-emitting optical fiber 2B. Furthermore, as... Figure 5As shown in (b), the optical inspection device 1B can also be configured such that, when viewed in a cross-section perpendicular to the fiber axis direction X of the light-receiving fiber 3B, the outer diameter D2 of the light-receiving fiber 3 is smaller than the outer diameter D1 of the light-emitting fiber 2. That is, one or both of the length and outer diameter of the first light-emitting part 21B can be configured to be larger than the first light-receiving part 31B. In this case, by having the light-shielding member 4 with dimensions equal to or greater than the length and outer diameter of the first light-receiving part 31, light directly from the first light-emitting part 21 toward the first light-receiving part 31 can be blocked. Preferably, the light-shielding member 4 has dimensions equal to the length and outer diameter of the first light-receiving part 31. Thus, for example, compared to the case where the light-shielding member 4 has dimensions equal to the length and outer diameter of the first light-receiving part 21B, the range of the irradiated light Lt blocked by the light-shielding member 4 can be reduced. Furthermore, since the area of ​​the illumination light Lt blocked by the light-shielding component 4 becomes narrower, the illumination range of the illumination light Lt becomes wider, and thus it is expected that the amount of reflected light Lt' reflected by the object being tested 6 will increase.

[0078] <Third Implementation Method> Figure 6 This is a cross-sectional view showing the arrangement of the light-emitting optical fiber, the light-receiving optical fiber, and the light-shielding component in the optical inspection device and optical fiber structure constituting the third embodiment. It should be noted that... Figure 6 The components shown are in relation to Figure 1 When the components of the optical inspection device 1 and the fiber optic structure 10 shown are the same, the same reference numerals are used.

[0079] exist Figure 1 The optical inspection device 1 shown depicts an optical fiber structure 10 with one light-emitting optical fiber 2 and one light-receiving optical fiber 3, but is not limited to this. For example, such as Figure 6 As shown in the optical inspection device 1C, the fiber optic structure 10C may also include two or more light-receiving optical fibers 3, each having a first light-receiving section 31. Therefore, by using multiple light-receiving optical fibers 3, the fiber optic structure 10C can receive more reflected light Lt'. Furthermore, by receiving more reflected light Lt' through these multiple light-receiving optical fibers 3, it is expected that the amount of reflected light Lt' propagating to the light detection section 33 will further increase.

[0080] Furthermore, the optical fiber structure 10 of the optical inspection device 1 may also include two or more light-receiving optical fibers 3 each having a first light-receiving section 31. This allows more illumination light Lt to reach the object being inspected 6. Moreover, due to the increased amount of illumination light Lt reaching the object being inspected 6, even when the reflectivity of the illumination light Lt in the object being inspected 6 is low, it is expected that the intensity of the reflected light Lt' will be sufficient to obtain high-precision detection results in the optical detection section 33.

[0081] In addition, the optical fiber structure 10 of the optical inspection device 1 may also have two or more light-emitting optical fibers 2 and two or more light-receiving optical fibers 3.

[0082] Here, one or more light-emitting optical fibers 2 and one or more light-receiving optical fibers 3 can be configured to form an optical fiber structure 10, with the first light-emitting part 21 and the first light-receiving part 31 separated by one or more light-shielding members 4 containing a non-transparent material. For example, in Figure 6 In the optical inspection device 1C, on one side of the light-emitting optical fiber 2 ( Figure 6 The first light-receiving part 31 is arranged side by side with the first light-emitting part 21, separated from the first light-emitting part 21 by the light-shielding member 4, and on the other side of the light-emitting optical fiber 2 ( Figure 6 The first light-receiving part 31 is also isolated from the first light-emitting part 21 by the light-shielding member 4 on the lower side, and an optical fiber structure 10C can be formed in which the first light-emitting part 21 and the first light-receiving part 31 are fixedly connected in a side-by-side configuration.

[0083] <Fourth Implementation> Figure 7 This is a cross-sectional view showing the arrangement of the light-emitting optical fiber, the light-receiving optical fiber, and the light-shielding component in the optical inspection device and optical fiber structure constituting the fourth embodiment. It should be noted that... Figure 7 The components shown are in relation to Figure 1 When the components of the optical inspection device 1 and the fiber optic structure 10 shown are the same, the same reference numerals are used.

[0084] exist Figure 1 In the optical inspection device 1 shown, the shape of the light-shielding component 4 is as follows: Figure 2 As shown in (b), a rectangular shape is illustrated when viewed in a cross-section perpendicular to the fiber axis direction X of the light-receiving fiber 3, but this is not a limitation. The shape of the light-shielding member 4, when viewed in a cross-section perpendicular to the fiber axis direction X of the light-receiving fiber 3, can be at least partially curved, for example, it can be circular or elliptical. In this case, the shape of the light-shielding member 4 is either cylindrical or ellipsoidal. On the other hand, as... Figure 7As shown in the optical inspection apparatus 1D, the shape of the light-shielding member 4D can be at least along one or both of the light-emitting optical fiber 2 and the light-receiving optical fiber 3. For example, the shape of the light-shielding member 4D can be configured to have concave surfaces 41, 41' at least in the portion facing one or both of the light-emitting optical fiber 2 and the light-receiving optical fiber 3. Thus, the shape of the light-shielding member 4D is along the shape of the light-emitting optical fiber 2 or the light-receiving optical fiber 3, at least in the portion having concave surfaces 41, 41'. In this way, the shape of the light-shielding member 4D is along the shape of the light-emitting optical fiber 2 or the light-receiving optical fiber 3, at least in the portion having concave surfaces 41, 41', thereby making it easier to arrange the light-emitting optical fiber 2 or the light-receiving optical fiber 3 at a desired position on the outer peripheral surface of the light-shielding member 4D.

[0085] Here, the 4D light-shielding component is as follows: Figure 7 As shown, preferably, an inclined surface 42, which is radially inclined towards the light-emitting optical fiber 2, is provided between the concave surface 41 facing the first light-emitting part 21 and the side surface 43 of the light-shielding member 4D. Furthermore, preferably, the light-shielding member 4D has an inclined surface 42', which is radially inclined towards the light-receiving optical fiber 3, between the concave surface 41' facing the first light-receiving part 31 and the side surface 43 of the light-shielding member 4D. With such inclined surfaces 42 and 42', when the illumination light Lt is irradiated onto the detection object 6, the light directly from the first light-emitting part 21 toward the first light-receiving part 31 is blocked, and the illumination light Lt from the first light-emitting part 21 toward directions other than the first light-receiving part 31 is difficult to block by the light-shielding member 4D. Furthermore, since the illumination light Lt is difficult to block by the light-shielding member 4D with inclined surfaces 42 and 42', a larger proportion of the illumination light from the light-emitting optical fiber 2 is reflected by the detection object 6 as reflected light Lt', thus it is expected that the first light-receiving part 31 will receive more reflected light Lt'.

[0086] <Other Implementation Methods> In the above embodiment, the first light guide portion 22 of the light-emitting optical fiber 2 is composed of an optical fiber whose cladding has not been removed, and the first light-emitting portion 21 of the light-emitting optical fiber 2 is formed in a shape in which part or all of the cladding of the optical fiber has been removed, but is not limited to this method.

[0087] For example, such as Figure 8As shown in (a) the light-emitting optical fiber 2E, the first light-emitting portion 21E of the light-emitting optical fiber 2E can also be formed in a shape where a portion of the cladding 27 of the optical fiber is removed, and a rough surface 27a is formed on the surface of the removed cladding 27. In this way, by forming the rough surface 27a on the surface of the cladding 27, irradiation light Lt can be irradiated from the first light-emitting portion 21E in various directions, such as a direction inclined relative to the optical fiber axis X of the light-emitting optical fiber 2E. Here, forming the rough surface 27a on the surface of the removed cladding 27 in the first light-emitting portion 21E can be achieved through surface roughening treatment using hydrofluoric acid, organic solvents, etc., or pattern forming treatment using lasers, etc. Furthermore, the portion of the light-emitting optical fiber 2E with the rough surface 27a formed tends to have low mechanical strength due to its thin wire diameter; therefore, from the viewpoint of improving the mechanical strength of this portion, the portion with the rough surface 27a can also be coated with a transparent resin (not shown). The refractive index of the transparent resin used in this case is not particularly limited.

[0088] In addition, such as Figure 8 (b) The light-emitting fiber 2F, Figure 8 As shown in (c) the light-emitting optical fiber 2F', the first light-emitting portion 21F of the light-emitting optical fiber 2F (or the first light-emitting portion 21F' of the light-emitting optical fiber 2F) is formed in a shape in which all or part of the cladding 27 of the optical fiber is removed, i.e., in the radial direction of the light-emitting optical fiber 2F (or the light-emitting optical fiber 2F'). A light-diffusing resin layer 25 with light-diffusing properties is formed on the surface of the core 26 (or the removed cladding 27), and a rough surface 25a can be formed on the surface of the light-diffusing resin layer 25 as needed. In this way, by forming a light-diffusing resin layer 25 on the surface of the core 26 or the cladding 27, light-diffusing light Lt can be irradiated from the first light-emitting portion 21F (or the first light-emitting portion 21F') in various directions, such as a direction inclined relative to the optical fiber axis direction X of the light-emitting optical fiber 2F (or the light-emitting optical fiber 2F'). By irradiating the object 6 with illumination light Lt in various directions, the paths of the reflected light Lt' become diverse, thus making it expected that the reflected light Lt' can be easily received at the first light-receiving part 31. Here, the light-diffusing resin layer 25 formed on the surface of the core 26 or the cladding 27 is preferably made of a transparent resin containing a light-diffusing substance such as titanium dioxide, and the light-diffusing resin layer 25 can be formed by coating the removed portion of the cladding 27 with transparent resin, etc. In addition, the rough surface 25a formed on the surface of the light-diffusing resin layer 25 can be formed by surface roughening treatment using hydrofluoric acid, organic solvents, etc., or by pattern forming treatment using laser, etc.

[0089] In addition, such as Figure 8As shown in (d) the light-emitting optical fiber 2G, the first light-emitting portion 21G of the light-emitting optical fiber 2G can also be formed by fusion splicing a coreless optical fiber or an optical diffusion optical fiber 28 to the front end portion of an optical fiber having a core 26 and a cladding 27. In this case, the fusion spliced ​​portion of the coreless optical fiber or the optical diffusion optical fiber 28 tends to have low mechanical strength. Therefore, from the viewpoint of improving the mechanical strength of the fusion spliced ​​portion, at least the fusion spliced ​​portion can be covered with a transparent or opaque resin layer 29. Here, from the viewpoint of extracting more irradiation light Lt from the coreless optical fiber or the optical diffusion optical fiber 28, the resin layer 29 covering the fusion spliced ​​portion preferably contains a transparent resin, and more preferably, from the viewpoint of improving the SN ratio of the extracted irradiation light Lt, it contains a transparent resin with a high refractive index. Here, for example, if the optical fiber fused to the coreless optical fiber or the optical diffusion optical fiber 28 contains a silica optical fiber, the transparent resin with a high refractive index preferably has a higher refractive index than the silica glass constituting the cladding 27 of the silica optical fiber. Furthermore, when the resin layer 29 comprises a transparent resin, the transparent resin may also contain light-diffusing substances such as titanium dioxide. Moreover, considering the possibility of balloon rupture, the material constituting the resin layer 29 is preferably a material used in medical applications.

[0090] In addition, especially as Figure 3 As shown, when the front end 3a of the first light-receiving section 31A of the light-receiving fiber 3A is located further forward than the front end 2a of the first light-emitting section 21A of the light-emitting fiber 2A, the first light-guiding section 22 of the light-emitting fiber 2 can, for example, be as follows: Figure 9 As shown in (a) the light-emitting optical fiber 2H, the first light-emitting portion 21H of the light-emitting optical fiber 2H is composed of an inclined surface 21a formed by obliquely cutting the core 26 and cladding 27 of the optical fiber. Furthermore, for example, as... Figure 9 As shown in (b) the light-emitting optical fiber 2I, the first light-emitting part 21I of the light-emitting optical fiber 2I can be composed of an inclined surface 21a in which the core 26 and cladding 27 of the optical fiber are cut into a conical shape concentric with the core 26.

[0091] On the other hand, in the above embodiment, the second light guide portion 32 of the light receiving optical fiber 3 is composed of an optical fiber whose cladding has not been removed, and the first light receiving portion 31 of the light receiving optical fiber 3 is formed in a shape in which part or all of the cladding of the optical fiber has been removed, but is not limited to this method.

[0092] For example, such as Figure 10As shown in (a) of the light-receiving optical fiber 3J, the first light-receiving section 31J of the light-receiving optical fiber 3J may also be formed with a portion of the cladding 37 of the optical fiber removed, and a rough surface 34a is formed on the surface of the removed cladding 37. In this way, by forming a rough surface 34a on the surface of the cladding 37, the first light-receiving section 31J can receive reflected light Lt' from various directions, such as the direction inclined relative to the optical fiber axis X of the light-receiving optical fiber 3J. Furthermore, by receiving reflected light Lt' from various directions by the first light-receiving section 31J, it is expected that the possibility of receiving reflected light Lt' in the first light-receiving section 31J can be increased.

[0093] In addition, such as Figure 10 As shown in (b) the light-receiving optical fiber 3K, the first light-receiving part 31K of the light-receiving optical fiber 3K can be a shape in which the entire cladding 37 of the optical fiber is removed.

[0094] In addition, such as Figure 11 As shown in (a) of the light-receiving optical fiber 3L, the first light-receiving portion 31L of the light-receiving optical fiber 3L can be formed such that a portion of the cladding 37 of the optical fiber is removed, and a rough surface 37a is formed on the surface of the removed cladding 37. Thus, by forming a rough surface 37a on the surface of the cladding 37, reflected light Lt' irradiated to the first light-receiving portion 31L can be received from various directions, such as a direction inclined relative to the optical fiber axis X of the light-receiving optical fiber 3L. Here, forming the rough surface 37a on the surface of the removed cladding 37 in the first light-receiving portion 31L can be achieved through surface roughening treatment using hydrofluoric acid, organic solvents, etc., or pattern forming treatment using a laser, etc. Furthermore, the portion of the light-receiving optical fiber 3L with the rough surface 37a tends to have low mechanical strength due to its thin wire diameter; therefore, from the viewpoint of improving the mechanical strength of this portion, the portion with the rough surface 37a can also be coated with a transparent resin (not shown). The refractive index of the transparent resin used in this case is not particularly limited.

[0095] In addition, such as Figure 11 (b) 3M optical fiber for receiving light Figure 11As shown in (c) the light-receiving optical fiber 3M', the first light-receiving portion 31M of the light-receiving optical fiber 3M (or the first light-receiving portion 31M' of the light-receiving optical fiber 3M) is formed in the thickness direction of the cladding 37 of the optical fiber, that is, in the radial direction of the light-receiving optical fiber 3M (or the light-receiving optical fiber 3M'), in a shape in which all or part of it is removed. Furthermore, a light-diffusing resin layer 35 with light-diffusing properties is formed on the surface of the core 36 (or the removed cladding 37), and a rough surface 35a can be formed on the surface of the light-diffusing resin layer 35 as needed. In this way, by forming a light-diffusing resin layer 35 on the surface of the core 36 or the cladding 37, light-diffusing light Lt can be irradiated from the first light-receiving portion 31M (or the first light-receiving portion 31M') in various directions, such as a direction inclined relative to the optical fiber axis direction X of the light-receiving optical fiber 3M (or the light-receiving optical fiber 3M'). By irradiating the object 6 with illumination light Lt in various directions, the paths of the reflected light Lt' become diverse, thus making it expected that the reflected light Lt' can be easily received at the first light-receiving part 31. Here, the light-diffusing resin layer 35 formed on the surface of the core 6 or the cladding 37 is preferably made of a transparent resin containing a light-diffusing substance such as titanium dioxide. The formation of this light-diffusing resin layer 35 can be performed by coating the removed portion of the core 36 or the cladding 37 with transparent resin, etc. In addition, the formation of a rough surface 35a on the surface of the light-diffusing resin layer 35 can be performed by surface roughening treatment using hydrofluoric acid, organic solvents, etc., or by pattern formation treatment using a laser, etc.

[0096] In addition, such as Figure 11 As shown in the light-receiving optical fiber 3N (d), the first light-receiving portion 31N of the light-receiving optical fiber 3N can also be formed by fusion splicing a coreless optical fiber or an optical diffusion optical fiber 38 to the front end portion of an optical fiber having a core 36 and a cladding 37. In this case, the portion of the coreless optical fiber or optical diffusion optical fiber 38 that is fused together tends to have low mechanical strength. Therefore, from the viewpoint of improving the mechanical strength of the fused portion, at least the fused portion can be covered with a transparent or opaque resin layer 39. Here, from the viewpoint of allowing more reflected light Lt' to be incident on the coreless optical fiber or optical diffusion optical fiber 38, the resin layer 39 covering the fused portion preferably contains a transparent resin, and more preferably, from the viewpoint of improving the SN ratio of the incident reflected light Lt', it contains a transparent resin with a high refractive index. Here, for example, if the optical fiber to which the coreless optical fiber or optical diffusion optical fiber 38 is fused together is made of silica optical fiber, the transparent resin with a high refractive index preferably has a higher refractive index than the silica glass constituting the cladding 37 of the silica optical fiber. Furthermore, when the resin layer 39 comprises a transparent resin, the transparent resin may also contain light-diffusing substances such as titanium dioxide. Moreover, considering the possibility of balloon rupture, the material constituting the resin layer 39 is preferably a material used in medical applications.

[0097] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and includes all the concepts and methods contained in the claims, and various changes can be made within the scope of the present invention.

[0098] [Explanation of reference numerals in the attached figures] 1, 1A, 1A', 1C, 1D Optical inspection devices 10, 10A, 10A', 10C fiber optic structures 15. Protrusion 2, 2A, 2A', 2E, 2F, 2F', 2G~2I optical fibers for light emission 2a Front end of the optical fiber for light emission 21, 21A, 21A', 21E, 21F, 21F', 21G~21I First Light-Emitting Part 21a Inclined surface 22, 22A, 22A' First Light Guide Section 23 Light Source 25, 35 light-diffusing resin layers Rough surfaces of 25a and 35a light-diffusing resin layers 26. Core of optical fiber for light emission 27. Cladding of optical fiber for light emission 27a Rough surface of the cladding of an optical fiber for light emission 28, 38 coreless optical fiber or optically diffused optical fiber 29, 39 (transparent or opaque) resin layers 3, 3A, 3A', 3J~3M, 3M', 3N optical fibers for receiving light 3a The front end of the optical fiber for receiving light 31, 31A, 31A', 31J~31M, 31M', 31N First Light Receiving Section 32, 32A, 32A' Second light guide section 33 Optical Detection Department 34 Display Section 36. Core of optical fiber for receiving light 37. Cladding of optical fiber for receiving light 37a Rough surface of the cladding of an optical fiber for light emission 4. 4D light-shielding components 4a Front end of the light-shielding component 41, 41' Concave surfaces of light-shielding components 42, 42' Inclined surfaces of the light-shielding components 43, 43' Side of the light-shielding component 5. Fixing part 6. Detection Objects 6a The inner surface of the tube to be tested Lt Irradiation Light Lt' reflected light Length dimension of P1 light-shielding component Length of the first light-emitting part of P2 Length of the first light-receiving part of P3 W is the width dimension of the light-shielding component. D1 is the outer diameter of the optical fiber that emits light. D2 Light-receiving optical fiber outer diameter X fiber axis direction

Claims

1. An optical inspection device, comprising: light source; At least one light-emitting optical fiber, the light-emitting optical fiber having a first light guide portion for transmitting light emitted from the light source, and a first light-emitting portion for illuminating the object to be detected as light transmitted in the first light guide portion; At least one optical fiber for receiving light, the optical fiber having a first light-receiving section for receiving reflected light after the illumination light emitted from the first light-emitting section is reflected by the detection object, and a second light-guiding section for transmitting the reflected light received by the first light-receiving section; and The optical detection unit detects reflected light propagating in the second light guide section of the light-receiving optical fiber. In the optical inspection device The light-emitting optical fiber and the light-receiving optical fiber are configured to form an optical fiber structure by separating the first light-emitting part and the first light-receiving part through a light-shielding component containing a non-transparent material.

2. The optical inspection device according to claim 1, wherein, The light-shielding component has dimensions equal to or greater than the length and outer diameter of the first light-receiving part.

3. The optical inspection device according to claim 1, wherein, The illumination light is emitted from the side of the first light-emitting part.

4. The optical inspection device according to claim 1, wherein, The length of the first light-receiving section of the light-receiving optical fiber is longer than the length of the first light-emitting section of the light-emitting optical fiber.

5. The optical inspection device according to claim 1, wherein, The front end of the first light-receiving part of the light-receiving optical fiber is located at a position that protrudes further forward than the front end of the first light-emitting part of the light-emitting optical fiber.

6. The optical inspection device according to any one of claims 1 to 5, wherein, The light-emitting optical fiber and the light-receiving optical fiber are made of quartz optical fiber or plastic optical fiber.

7. An optical fiber structure, which possesses: At least one light-emitting optical fiber, the light-emitting optical fiber having a first light-guiding section for transmitting light emitted from a light source, and a first light-emitting section for illuminating the object being detected as illumination light by the light transmitted in the first light-guiding section; and At least one optical fiber for receiving light, the optical fiber having a first light-receiving part for receiving reflected light after the illumination light emitted from the first light-emitting part is reflected by the detection object, and a second light-guiding part for transmitting the reflected light received by the first light-receiving part. The light-emitting optical fiber and the light-receiving optical fiber are configured to form an optical fiber structure by separating the first light-emitting part and the first light-receiving part through a light-shielding component containing a non-transparent material.

8. The optical fiber structure according to claim 7, wherein, The light-shielding component has dimensions equal to or greater than the length and outer diameter of the first light-receiving part.

Images