Light irradiation device and in-vivo light irradiation assembly using same

Abstract

Provided is a light irradiation device which is small and has heat dissipation and electrical insulation. The light irradiation device is provided with: a light-emitting element that emits light having a prescribed wavelength; a support body on which the light-emitting element is mounted; an insulated wire electrically connected to the light-emitting element; and an insulating layer that integrally covers the outer surface of a structure including the light-emitting element, the support body, and the insulated wire.

Description

Light irradiation device and in vivo light irradiation assembly using the same

[0001] The present disclosure relates to a light irradiation device and an in-vivo light irradiation assembly using the same.

[0002] Endoscopes are used for in vivo diagnosis and treatment. Treatments that combine endoscopy with laser irradiation are also being performed. In photoimmunotherapy, which has recently attracted attention, if the affected area is located on the body surface or shallow from the body surface, light of a specific wavelength that reacts with a photosensitizer accumulated in cancer cells is irradiated from the body surface. If the affected area is located deep from the body surface, laser light is irradiated to the affected area inside the body by puncturing. Specifically, an optical fiber is inserted into a blood vessel, digestive tract, or other lumen, and laser light of a specific wavelength is irradiated to the affected area inside the body. A deployable balloon light for endoscopic examination has been proposed (see, for example, Patent Document 1).

[0003] Special Publication No. 2022-535144

[0004] The present disclosure provides a compact light irradiation device that has heat dissipation and electrical insulation properties, and is also suitable for use in a laser irradiation device that uses an optical fiber.

[0005] In one embodiment, the light irradiation device includes: a light emitting element that emits light of a predetermined wavelength; a support body on which the light emitting element is mounted; an insulated wire electrically connected to the light emitting element; and an insulating layer that integrally covers an outer surface of a structure including the light emitting element, the support body, and the insulated wire.

[0006] A compact light-emitting device having heat dissipation and electrical insulation properties can be realized.

[0007] FIG. 1 is a diagram showing an example of an in vivo light-illumination assembly using the light-illumination device of the first embodiment. FIG. 2 is a schematic diagram showing an example of the configuration of the light-illumination device of the first embodiment. FIG. 3 is a schematic diagram showing another example of the configuration of the light-illumination device of the first embodiment. FIG. 4 is a perspective view of a light-illumination device main body before being sealed with an insulating layer. FIG. 5 is a schematic diagram of a light-emitting element mounted on a support body. FIG. 6 is a schematic diagram showing an example of lamination of a support body and a light-emitting element. FIG. 7 is a diagram showing an example of an in vivo light-illumination assembly using the light-illumination device of the second embodiment. FIG. 8 is a diagram showing an example of the arrangement of optical elements in the light-illumination device of the second embodiment. FIG. 9 is a schematic diagram of a light-illumination device of the third embodiment. FIG. 10 is a schematic diagram showing an example of a light-emitting element used in the third embodiment. FIG. 11 is a perspective view of the light-emitting element mounting surface side of the support body used in the third embodiment. FIG. 12 is a perspective view of the back side of the support body used in the third embodiment. FIG. 13 is a diagram showing the electrical characteristics and light output characteristics of the light-illumination device of the embodiment. FIG. 14 is a diagram showing the thermal resistance of the light-illumination device of the embodiment.

[0008] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. The following description is intended to embody the technical concept of the present disclosure, and unless otherwise specified, the present disclosure is not limited to the following description. In each drawing, components having the same function may be assigned the same reference numerals. For convenience, the embodiments may be shown separately in consideration of ease of explanation or understanding of the main points, but partial substitution or combination of configurations shown in different embodiments or examples is possible. In the embodiments shown later, differences from the previously shown embodiments will be mainly described, and redundant description of matters common to the previously shown embodiments may be omitted. The size and positional relationship of components shown in each drawing may be exaggerated for clarity.

[0009] First Embodiment FIG. 1 is a diagram illustrating an example of an in vivo light irradiation assembly 100 using a light irradiation device 10 according to the first embodiment. The in vivo light irradiation assembly 100 includes a catheter 50 and a light irradiation device 10 inserted into the catheter 50. The catheter 50 is filled with a refrigerant 51 at least during use. The in vivo light irradiation assembly 100 is used for treatment, diagnosis, sensing, and the like. The light irradiation device 10 is inserted into the catheter 50 in the direction indicated by the white arrow "insertion direction" in the figure and introduced into a living body. Because the light irradiation device 10 is a heat-generating body, a refrigerant 51 is supplied into the catheter 50, and the heat-generating portion is cooled during use. Therefore, the distal end of the light irradiation device 10 is integrally covered with an insulating layer 16. The refrigerant 51 may be, for example, saline, blood, lymph, or the like, and the refrigerant temperature is, for example, approximately 10°C to 36°C. The light irradiation device 10 is inserted into the vicinity of a target site such as an affected area in a living body using a catheter 50, so that it is possible to directly irradiate light onto an affected area such as a tumor, and to inspect and confirm a target site for diagnosis, sensing, etc., without using an optical fiber.

[0010] 2A and 2B are schematic diagrams showing examples of the configuration of the light irradiation device 10 of the first embodiment shown in FIG. In both the light irradiation device 10A of FIG. 2A and the light irradiation device 10B of FIG. 2B, the light-emitting element, the support on which the light-emitting element is mounted, and the insulated wire electrically connected to the light-emitting element are integrally covered with an insulating layer, but the covering state of the insulating layer differs. In the coordinate systems of FIGS. 2A and 2B, the optical axis direction is the Z direction, the direction in which the light-emitting element is mounted on the support is the Y direction, and the direction perpendicular to the Z direction and the Y direction is the X direction. The light irradiation device 10A shown in FIG. 2A includes a light-emitting element 11 that emits light of a predetermined wavelength, an optical component 17 onto which the light emitted from the light-emitting element 11 is incident, a support 12 on which the light-emitting element 11 and the optical component 17 are mounted, an insulated wire 14 electrically connected to the light-emitting element 11, and an insulating layer 16A that integrally covers the outer surface of the structure including the light-emitting element 11, the optical component 17, the support 12, and the insulated wire 14. A space 13 is provided between the light-emitting surface 111 of the light-emitting element 11 and the light-incident surface 171 of the optical component 17. By providing the space 13 and shortening the distance that light emitted from the light-emitting element 11 travels through the insulating layer, the influence of light refraction by the insulating layer can be reduced, making it easier to control the spread of light emitted from the light-emitting element 11. The insulating layer 16A is, for example, a coating formed by applying a polysilazane solution and silicating it (hereinafter referred to as a "polysilazane coating"), and is translucent to the light emitted from the light-emitting element 11. By employing a polysilazane coating, the thickness of the insulating layer can be reduced, improving heat dissipation while ensuring insulation. The light-emitting surface 111 of the light-emitting element 11 and the light-incident surface 171 of the optical component 17 face each other across the space 13. Light emitted from the light-emitting surface 111 passes through the insulating layer 16A, the space 13, and the insulating layer 16A and enters the light-incident surface 171 of the optical component 17. 2A seals the laminated structure along the surface shapes of the support 12 and the components mounted on the support 12. When the light irradiation device 10A is inserted into a catheter 50 for use, the space 13 may be filled with a coolant 51. In this case, light passes through the coolant 51 in the space 13 and enters the light incident surface 171 of the optical component 17.

[0011] In this configuration example, the longitudinal direction of the support 12 is parallel to the Z direction. The light irradiation device 10 of the first embodiment is inserted into the catheter 50 in the +Z direction, and the insulated wires 14 including the first insulated wire 14a and the second insulated wire 14b extend in the -Z direction. The support 12 is made of silicon (Si), aluminum nitride (AlN), silicon nitride (SiN), sapphire (Al ２ O ３ , glass, quartz, ceramics or other insulating material, and the light emitting element 11 is mounted on a light emitting element mounting surface 121 of the support 12 .

[0012] An optical component 17 is mounted on the light-emitting element mounting surface 121 of the support 12 together with the light-emitting element 11, and the light incident surface 171 of the optical component 17 is inclined relative to the light-emitting element mounting surface 121. This allows the light incident surface 171 of the optical component 17 to function as a reflecting surface, and the output light Lout of the light irradiation device 10A is extracted in the direction indicated by the dashed arrow. In the configuration example of FIG. 2A , the optical component 17 is a reflective member that guides the light emitted from the light-emitting element 11 in a direction intersecting the light-emitting element mounting surface 121 of the support 12 (e.g., the +Y direction). This allows the light to be emitted in the circumferential direction of the light irradiation device. The optical component 17 may be a mirror that reflects light incident on the light incident surface 171. The mirror may have a reflective layer made of metal and / or a dielectric multilayer film. This allows for efficient reflection of light.

[0013] The insulated wires 14 include a first insulated wire 14a electrically connected to one electrode (also referred to as the first electrode) of the light-emitting element 11 on the light-emitting element mounting surface 121, which is the first surface of the support 12 on which the light-emitting element 11 is mounted, and a second insulated wire 14b electrically connected to the other electrode (also referred to as the second electrode) of the light-emitting element 11 on the back surface 122 (also referred to as the second surface) opposite the light-emitting element mounting surface 121. The use of the insulated wires enables electrical current to be passed through the light-emitting element 11. One of the features of the light irradiation device 10A is that the electrical connections between the first insulated wire 14a and the second insulated wire 14b and the light-emitting element 11 are integrally sealed with an insulating layer 16A along with the support 12, the light-emitting element 11, and the optical component 17. The thickness of the insulating layer 16A is thinner than the thickness of the light-emitting element 11. By integrally covering the light irradiation device 10A with the insulating layer 16 that is thinner than the light emitting element 11, a small light irradiation device 10A with ensured electrical insulation is realized, which facilitates insertion into the catheter 50. Furthermore, by making the thickness of the insulating layer 16A thinner than the thickness of the light emitting element, the thermal resistance of the insulating layer 16 can be reduced, and heat dissipation can be improved.

[0014] The width of the support 12 in the X direction is a width that allows it to be easily inserted into the catheter 50, but from the viewpoint of widening the cooling area (i.e., heat dissipation area) by the refrigerant 51, it may be set as wide as possible within a range that allows it to be smoothly inserted into the catheter 50. The thickness of the support 12 in the Y direction is a thickness that can stably support the light-emitting element 11 and that allows it to be smoothly inserted into the catheter 50 with the light-emitting element 11 mounted thereon. As an example, the thickness of the support 12 is about 0.075 to 0.3 mm.

[0015] The insulating layer 16A, which integrally seals the support 12 and the components on the support 12, is made of a polysilazane coating or an insulating resin such as an epoxy resin, a silicone resin, an acrylic resin, or a thermoplastic resin. By sealing the components integrally with an insulating layer, i.e., in a single process, the process can be simplified. When using these resins, a biocompatible insulating resin with high thermal conductivity is preferably used for the insulating layer 16A. Examples of such insulating resins include polycarbonate (PC), polyethylene terephthalate (PET), polyimide (PI), polyurethane, and polyesterimide, whose components and compositions have been adjusted to mitigate adverse effects on living organisms. The insulating layer 16A may be a polysilazane coating with a biocompatible resin layer formed on the surface. The insulating layer 16A isolates the electrical connection between the light-emitting element 11 and the first and second insulated wires 14a and 14b from the refrigerant 51. While maintaining this sealed state, the first insulated wire 14a and the second insulated wire 14b are pulled out in the −Z direction from the insulating layer 16A.

[0016] The first insulated wire 14a and the second insulated wire 14b are cooled by the refrigerant 51 and also function as heat dissipation materials. The insulated wire 14 is, for example, an enameled wire, in which metal wiring made of a good conductor such as Cu or Ni is coated with an insulating polyurethane coating. Instead of polyurethane, an insulating resin such as polyester, polyesterimide, polyamideimide, or polyimide may be used. By using the insulating coating, which is the surface coating of the insulated wire 14, as a heat dissipation material, heat generated by the light-emitting element 11 can be dissipated to the outside. When rectangular enameled wires are used as the first insulated wire 14a and the second insulated wire 14b, the resulting wiring is wider, allowing for a larger bonding area with the support 12. Furthermore, for the same circumscribed circle area, the rectangular enameled wire can have a smaller circumscribed circle area than a round enameled wire, thereby enabling a more compact design.

[0017] The light-emitting element 11 is, for example, an edge-emitting laser element that resonates in a direction parallel to the Z-axis. When an edge-emitting laser element is used as the light-emitting element 11, one end face in the resonance direction becomes the light-emitting surface 111. An optical component 17 is disposed on the light-emitting element mounting surface 121 of the support 12 so as to face the light-emitting surface 111 of the light-emitting element 11, and guides the light emitted from the edge-emitting laser element in a direction intersecting with the light-emitting element mounting surface 121. The direction intersecting with the light-emitting element mounting surface 121 is any direction except for directions parallel to the light-emitting element mounting surface 121, but can be, for example, in the range of 50° to 130° with respect to the light-emitting element mounting surface 121. It may also be a direction perpendicular to the light-emitting element mounting surface 121. Here, the "perpendicular" direction does not need to be strictly perpendicular to the light-emitting element mounting surface 121, and includes a range of 90°±5° taking into account manufacturing errors and surface conditions of the support 12 and the optical component 17. Light emitted from the light-emitting element 11 is reflected by the light incident surface 171 of the optical component 17 and is irradiated in a predetermined direction. When a polysilazane coating is used for the insulating layer 16A, the light can also be reflected by the polysilazane coating. The optical component 17 may be configured by combining a first optical element that controls the spread angle of the light emitted from the light-emitting element 11 and a second optical element that has a reflecting function, as long as a predetermined space 13 is maintained between the optical component 17 and the light exit surface 111 of the light-emitting element 11.

[0018] In the configuration example of FIG. 2A , the first insulated wire 14a and the second insulated wire 14b are connected to the top surface of the light-emitting element 11 and the back surface 122 of the support 12, respectively, so as not to interfere with light emission in the Z direction from the light-emitting element 11 and reflection by the optical component 17. A conductive layer 124 is formed on at least a portion of the surface of the support 12. In the example of FIG. 2A , the support 12 has a light-emitting element mounting surface 121, a back surface 122, and a conductive layer 124 formed on at least a portion of a side surface connecting the light-emitting element mounting surface 121 and the back surface 122. As a result, the first insulated wire 14a is electrically connected directly or indirectly to one electrode of the light-emitting element 11 on the light-emitting element mounting surface 121 side of the support 12. The second insulated wire 14b is electrically connected directly or indirectly to the other electrode of the light-emitting element 11 on the back surface 122 of the support 12 via the conductive layer 124 formed on the support 12.

[0019] The light-emitting element 11 and optical component 17 mounted on the support 12 of the light-irradiation device 10B in FIG. 2B, as well as the insulated wire 14 electrically connected to the light-emitting element 11, are configured in the same manner as the light-irradiation device 10A, but differ from the light-irradiation device 10A in the covering state with the insulating layer 16B. The thickness of the insulating layer 16B may be at least partially thicker than the thickness of the light-emitting element 11. In this case, the space between the light-emitting surface 111 of the light-emitting element 11 and the light-incident surface 171 of the optical component 17 may be filled with the insulating layer 16B. Light emitted from the light-emitting surface 111 of the light-emitting element 11 passes through the insulating layer 16B and enters the light-incident surface 171 of the optical component 17. The insulating layer 16B may be made of the same material as the insulating layer 16A described above. By making the insulating layer 16B thick, the entire support 12, light-emitting element 11, optical component 17, and insulated wire 14 can be stably supported, and the optically coupled portions and the electrical connected portions can be reliably prevented from coming into contact with the refrigerant.

[0020] 3 is a perspective view of the light irradiation device body before being sealed with the insulating layer 16 (or 16A or 16B). A predetermined space 13 is provided between the light emission surface 111 of the light emitting element 11 and the light incidence surface 171 of the optical component 17. Light emitted from the light emitting element 11 passes through the space 13 and enters the optical component 17, where it is reflected in a predetermined direction. A conductive layer 124 is formed to cover at least a portion of the light emitting element mounting surface 121 of the support body 12, at least a portion of the side surfaces, and at least a portion of the back surface 122. The top surface of the light emitting element 11 is connected to the first insulated wire 14a, and the bottom surface of the light emitting element 11 is connected to the conductive layer 124 formed on the light emitting element mounting surface 121.

[0021] A portion of the insulating coating of the first insulated wire 14a is removed, and the internal metal wiring is connected to one electrode of the light-emitting element 11. A portion of the insulating coating of the second insulated wire 14b is removed, and the internal metal wiring is electrically connected to the other electrode of the light-emitting element 11. In the example of FIG. 3 , a conductive layer 124 is formed from the light-emitting element mounting surface 121 of the support 12, through the side surface, to the back surface 122, and the internal metal wiring of the second insulated wire 14b is connected to the conductive layer 124 on the back surface 122 of the support 12. This provides an electrical connection between the other electrode of the light-emitting element 11 and the second insulated wire 14b. By providing the conductive layer 124 for electrical connection on the surface of the support 12, the conductive layer 124 can be used as a heat dissipation member.

[0022] As described above, the optical component 17 is mounted on the support 12 and faces the light emission surface 111 of the light emitting element 11. The body of the optical component 17 is formed of a dielectric material such as glass, and a thin silver film is formed on the light incident surface 171, but this example is not limiting. A thin film of aluminum, aluminum alloy, gold, nickel, platinum, or the like may be formed on the light incident surface (i.e., the reflective surface) of the plastic body. A dielectric multilayer film may be formed instead of a metal reflective film. The support 12, the light emitting element 11, the optical component 17, and a portion of the insulated electric wire 14 are covered with a light-transmitting insulating layer 16A or 16B by a dipping method, a spraying method, or the like.

[0023] FIG. 4 is a schematic diagram of the light-emitting element 11 mounted on the support 12. The light-emitting element 11 is, for example, an edge-emitting laser element having a ridge structure. The light-emitting element 11 includes an n-side electrode 113, an n-side semiconductor layer 114, an active layer 115, a p-side semiconductor layer 116, and a p-side electrode 118. The n-side semiconductor layer 114 may include an optical guide layer, a cladding layer, a contact layer, etc., doped with n-type impurities. The p-side semiconductor layer 116 may include an optical guide layer, a cladding layer, a contact layer, etc., doped with p-type impurities. The p-side electrode 118 is electrically connected to the first insulated wire 14a. When an ITO electrode is used as the p-side electrode 118, the p-side electrode 118 may also serve as the cladding layer. The p-side electrode 118 is electrically connected to the second insulated wire 14b via a conductive layer 124 formed on the support 12. 4, the n-side electrode 113 and the first insulated wire 14a are directly connected, but they may be indirectly connected, for example, a second support may be disposed between the n-side electrode 113 and the first insulated wire 14a. As will be described later with reference to FIG. 5, by sandwiching the light-emitting element 11 between two supports 12, heat dissipation can be improved.

[0024] The semiconductor material and its composition of the light-emitting element 11 are designed to emit laser light of a desired wavelength. When the light-emitting element 11 is used as an ultraviolet laser, a violet laser, a blue laser, or a green laser, GaN-based materials such as GaN, InGaN, and AlGaN are used. When the light-emitting element 11 is used as a red laser, an infrared laser, or a near-infrared laser, GaAs-based materials such as GaAs and AlGaAs, or InP-based materials such as InAlGaP and GaInP are used. The ridge width may be wide to ensure the gain of the active layer 115, from the viewpoint of sealing the light-emitting element 11, the first insulated wire 14a, and the second insulated wire 14b, together with the insulating layer 16A or 16B, when the light-emitting element 11 is mounted on the support 12. The ridge width may be designed to be, for example, 2 μm to 100 μm. The transverse mode may be multimode or single mode.

[0025] Unlike fiber-based or external light source-based irradiation devices, the light emitted by the light-emitting element 11 is linearly polarized, and the direction of the linear polarization after emission can be changed by changing the reflection direction using an optical component 17 such as a mirror. This makes it possible, for example, to reduce the reflectance when the light is incident on a living body and improve the transmittance through the living body. Even light that is in a specific polarization state when emitted as laser light may change its polarization state or become depolarized while passing through a transmission medium such as an optical fiber. In this embodiment, light can be directly irradiated onto an affected area inside the body without using an optical fiber, so light can be irradiated onto a target location such as an affected area while maintaining a specific polarization state.

[0026] 5 is a schematic diagram showing an example of a stack of the support 12 and the light-emitting element 11. In this configuration example, the light-emitting element 11 is sandwiched between a first support 12-1 and a second support 12-2. The first support 12-1 contacts the top surface of the light-emitting element 11, and the second support 12-2 contacts the bottom surface of the light-emitting element 11. By sandwiching the light-emitting element 11 between the first support 12-1 and the second support 12-2, heat can be efficiently dissipated to the upper and lower sides of the light-emitting element 11, thereby improving the heat dissipation performance of the light irradiation device 10. The rear end of at least one of the first support 12-1 and the second support 12-2 may be extended in the −Z direction. 5, it is assumed that light is extracted in a direction (for example, the Y direction) non-parallel to the optical axis (Z axis) by the optical component 17, but as will be described in the second embodiment, if light is extracted in a direction parallel to the light-emitting element mounting surface 121 of the support body 12, the tip sides of the first support body 12-1 and the second support body 12-2 may be extended long in the +Z direction. The entire structure in FIG. 5 is covered with an insulating layer 16A or 16B.

[0027] Second Embodiment Fig. 6 is a diagram showing an example of an in vivo light irradiation assembly 200 using a light irradiation device 20 according to a second embodiment. The in vivo light irradiation assembly 200 includes a catheter 50 and a light irradiation device 20 inserted into the catheter 50, and the catheter 50 is filled with a refrigerant 51 at least during use. The in vivo light irradiation assembly 200 is used for treatment, diagnosis, sensing, and the like. As with the light irradiation device 10 according to the first embodiment, the light irradiation device 20 is inserted into the catheter 50 in the "insertion direction" indicated by the white arrow in the figure and introduced into a living body. The inside of the catheter 50 is filled with a refrigerant 51.

[0028] The light irradiation device 20 is used with its heat-generating portion cooled. In the second embodiment, the insulated wires 24 are drawn from both sides of the insulating layer 26 along the optical axis to enhance heat dissipation. The insulated wires 24 include a first insulated wire 24a and a second insulated wire 24b electrically connected to the light emitting element 11. The length of the insulated wires 24 drawn from the insulating layer 26 in the +Z direction may be shorter than the length of the insulated wires 24 drawn from the insulating layer 26 in the −Z direction. To achieve this configuration, light emitted from the light emitting element 11 is guided in a direction parallel to the light emitting element mounting surface or in a direction not obstructed by the first insulated wire 24a and the second insulated wire 24b. The insulating layer 26 may be thinly coated along the surface shapes of the support 12 and the components mounted on the support 12 to enhance heat dissipation, as shown in FIG. 2A , or may be thickly coated partially, filling the spaces between the components mounted on the support 12, as shown in FIG. 2B , while minimizing the overall thickness of the light irradiation device to ensure electrical insulation from the refrigerant 51.

[0029] 7 is a diagram showing an example of the arrangement of the optical components 27 of the light irradiation device 20. To clearly illustrate the configuration, FIG. 7 shows a state before the first insulated wire 24a and the second insulated wire 24b are electrically connected to the light emitting element 11. Light emitted from the light emitting surface 111 of the light emitting element 11 is reflected by the optical components 27 in a direction substantially parallel to the light emitting element mounting surface 121, and output light Lout of the light irradiation device 20 is extracted in the direction of the dashed arrow. As long as the reflected light from the optical components 27 is not obstructed by the first insulated wire 24a and the second insulated wire 24b, the light may be reflected in a non-parallel direction from the light emitting element mounting surface 121.

[0030] In the actual light irradiation device 20, the light emitting element 11, the optical component 27, and the electrical connection portions between the light emitting element 11 and the first insulated wire 24a and the second insulated wire 24b are sealed integrally with the support body 12 by the insulating layer 26. At least the portion of the insulating layer 26 that exists between the light emitting surface 111 of the light emitting element 11 and the light incident surface 171 of the optical component is translucent to the light emitted from the light emitting element 11.

[0031] The light-emitting element 11 is, for example, an edge-emitting laser element. The light-emitting element 11 may be a laser element having a wide ridge structure similar to that of the first embodiment. The direction parallel to the Z axis of the light-emitting element 11 is the resonance direction. An optical component 27 is disposed on the light-emitting element mounting surface 121 of the support 12, and guides light emitted from the emission surface of the laser element in a direction parallel to the light-emitting element mounting surface 121 of the support 12. The first insulated wire 24a and the second insulated wire 24b (see FIG. 6) extend in the +Z direction and the −Z direction, sandwiching the light-emitting element 11 and the support 12 therebetween, so that the light from the light-emitting element 11 is reflected by the optical component 27 in a direction that is not obstructed by the first insulated wire 24a and the second insulated wire 24b.

[0032] The optical component 27 reflects light emitted from the light-emitting surface of the light-emitting element 11, for example, in the X direction parallel to the light-emitting element mounting surface 121. Here, the "parallel" direction does not necessarily have to be strictly parallel to the light-emitting element mounting surface 121; it may have an error of approximately ±10°, taking into account the surface condition of the support 12, manufacturing errors of the optical component 27, etc. As long as the laser light reflected by the optical component 27 does not interfere with the first insulated wire 24a and the second insulated wire 24b, it may be extracted at an angle other than parallel. The optical component 27 is preferably as thick as or thinner than the light-emitting element 11. The optical component 27 may be a flattened mirror or prism, or a metapolarizing element with a metasurface element inserted. The optical component 27 may also be an optical element having a lens function that controls the divergence angle of the light emitted from the light-emitting element 11. The optical component 27 may be composed of two or more optical elements. For example, it may have an optical element having a lens function that controls the spread angle of the light emitted from the light emitting element 11, and an optical element that reflects the light whose spread angle has been controlled by the optical element at a predetermined angle.

[0033] The insulating layer 26 integrally seals the locations requiring electrical insulation in a state in which the first insulated wire 24a and the second insulated wire 24b are extended in the +Z direction and the −Z direction from both ends of the support body 12 in the optical axis direction. The electrical connection portions between the light emitting element 11 and the first insulated wire 24a and the second insulated wire 24b, as well as at least the light emission surface 111 of the light emitting element 11 and the light incidence surface 171 of the optical component 17, are sealed by the insulating layer 26 and isolated from the coolant 51. The insulating layer 26 is preferably made of a biocompatible resin with high thermal conductivity.

[0034] At least one of the ends of the support 12 in the longitudinal direction (Z direction) may protrude from the insulating layer 26. The support 12 protruding from the insulating layer 26 comes into contact with the refrigerant 51, thereby ensuring the heat dissipation of the light irradiation device 20. Furthermore, by extending the first insulated wire 24a and the second insulated wire 24b to both longitudinal sides of the support 12, the heat dissipation is further improved compared to the first embodiment. As in the first embodiment, the overall thickness and width of the light irradiation device 20 are approximately 0.5 mm, thereby realizing an ultra-compact light irradiation device 20 that can be mounted on a catheter 50. In the configuration of the second embodiment, the light emitting element 11 may be sandwiched between two supports 12-1 and 12-2, as shown in FIG. 5 . In the second embodiment, light emitted from the light emitting element 11 is extracted in a direction not obstructed by the support 12. Therefore, by sandwiching the light emitting element 11 between the two supports 12-1 and 12-2, the heat dissipation of the light irradiation device 20 can be further improved.

[0035] 8 is a schematic diagram of a light irradiation device 30 according to a third embodiment. As in the first and second embodiments, the light irradiation device 30 is also mounted on a catheter 50 (see FIGS. 1 and 6 ) for use, and the light irradiation device 30 and the catheter 50 can form an in-vivo light irradiation assembly. In the third embodiment, a vertical cavity surface emitting laser (VCSEL) is used as the light emitting element 31.

[0036] The light irradiation device 30 includes two light-emitting elements 31 that emit light of a predetermined wavelength, a support 12 on which the light-emitting elements 31 are mounted, and insulated wires 34 electrically connected to the light-emitting elements 31. The insulated wires 34 include a first insulated wire 34a connected to one electrode of each light-emitting element 31 and a second insulated wire 34b connected to the other electrode. The light-emitting surfaces of the light-emitting elements 31 and the electrical connection portions between the light-emitting elements 31 and the insulated wires 34 are integrally sealed with the support 12 by an insulating layer 36. At least one of both ends of the support 12 along the longitudinal direction (Z direction) may protrude from the insulating layer 36. At least the portion of the insulating layer 36 that covers the light-emitting surfaces is translucent. The thickness of the insulating layer 36 may be thicker or thinner than the thickness of the light-emitting elements 31.

[0037] The light emission surface of the VCSEL used in the light emitting element 31 is parallel to the light emitting element mounting surface 121 of the support body 12, and the laser light emitted from the VCSEL is emitted in a direction perpendicular to the light emitting element mounting surface 121, as indicated by the white arrow in the figure. In this configuration, no optical components such as mirrors are required.

[0038] The first insulated wire 34a and the second insulated wire 34b are, for example, two-core enameled wires. The first insulated wire 34a is connected to one electrode of each light-emitting element 31 on the light-emitting element mounting surface 121 side of the support body 12, and the second insulated wire 34b is connected to the other electrode of each light-emitting element 31 on the back surface (the surface opposite the light-emitting element mounting surface 121) of the support body 12. The first insulated wire 34a and the second insulated wire 34b are drawn out of the insulating layer 36 from at least one of both ends of the support body 12 in the longitudinal direction, with the support body 12 sandwiched therebetween.

[0039] FIG. 9 is a schematic diagram showing an example of a light-emitting element 31 used in the third embodiment. The VCSEL, which is the light-emitting element 31, has a layered structure in which a semiconductor substrate 401, an n-side reflective film 402, an n-type semiconductor layer 403, an active layer 404, a p-type semiconductor layer 405, and a p-side reflective film 406 are stacked in this order in the −Y direction. The light emission direction is the +Y direction. The p-type and n-type conductivity types may be reversed. The semiconductor substrate 401 may be removed. The n-type semiconductor layer 403 has a flat portion and a convex portion protruding from the flat portion in the −Y direction. An active layer 404 is provided on the upper surface of the convex portion of the n-type semiconductor layer 403. A p-type semiconductor layer 405 is provided on the upper surface of the active layer 404, and a p-side reflective film 406 is provided on the upper portion of the p-type semiconductor layer 405 except for the peripheral region. A p-side contact layer may be provided between the p-type semiconductor layer 405 and the p-side reflective film 406.

[0040] The light-emitting element 31 includes an insulating layer 407 that covers the upper surface of the flat portion and the side surfaces of the convex portion of the n-type semiconductor layer 403, the side surfaces of the active layer 404, and the peripheral region of the side surfaces and upper surface of the p-type semiconductor layer 405. The light-emitting element 31 includes a p-side electrode 408 electrically connected to the p-type semiconductor layer 405 and an n-side electrode 409 electrically connected to the n-type semiconductor layer 403. The side on which the p-side electrode 408 and the n-side electrode 409 are provided is disposed on the light-emitting element mounting surface 121 of the support 12. A conductive connection layer (or bump) connected to the light-emitting element mounting surface 121 of the support 12 may be provided so that the heights of the p-side electrode 408 and the n-side electrode 409 in the -Y direction are aligned. When the light-emitting element 31 is flip-chip mounted on the support 12 using the conductive connection layer connected to the p-side electrode 408 and the n-side electrode 409, the p-side reflective film 406 does not interfere with the light-emitting element mounting surface of the support 12.

[0041] The n-side reflective film 402 and the p-side reflective film 406 may each be formed of, for example, a distributed Bragg reflector (DBR). A DBR has a structure in which multiple high-refractive index layers and multiple low-refractive index layers are alternately stacked. The DBR has a wavelength range of high reflectivity called a stop band. The center wavelength and wavelength width of the stop band are determined by the refractive index and thickness of the high-refractive index layers and the refractive index and thickness of the low-refractive index layers. The reflectivity in the stop band of the DBR increases with the refractive index difference between the high-refractive index layers and the number of layers stacked.

[0042] In the example shown in FIG. 9 , a standing wave is formed between the n-side reflective film 402 and the p-side reflective film 406. The wavelength of the standing wave in air is within the stop band of the n-side reflective film 402 and the p-side reflective film 406, and this wavelength is the oscillation wavelength of the laser light. An integer multiple of half the oscillation wavelength is equal to the optical distance between the opposing reflective surfaces of the n-side reflective film 402 and the p-side reflective film 406. The optical distance is calculated by multiplying the distance light actually propagates through a medium by the refractive index of that medium. Current can be injected into the active layer 404 by applying a forward voltage between the p-side electrode 408 and the n-side electrode 409. This current injection causes a population inversion in the active layer 404, resulting in light amplification by stimulated emission at the oscillation wavelength, i.e., laser oscillation. As described above, the VCSEL of this embodiment is designed so that the p-side electrode 408 and the n-side electrode 409 are the mounting surface, and laser light is extracted from the semiconductor substrate 401 side.

[0043] The configuration of the VCSEL shown in FIG. 9 is an example. The components included in the VCSEL may be formed from known materials. The shapes of some of the components included in the VCSEL may be modified, or other components may be further included. A configuration in which laser light is extracted from the side opposite to the semiconductor substrate 401 may also be used.

[0044] FIG. 10A is a perspective view of the light-emitting element mounting surface 121 side of the support body 12 used in the third embodiment, and FIG. 10B is a perspective view of the back surface 122 side of the support body. Here, the surface opposite the light-emitting element mounting surface 121 is referred to as the "back surface." Conductive layers 124 and 125 are formed on the light-emitting element mounting surface 121 of the support body 12. The conductive layer 124 is formed on the light-emitting element mounting surface 121 of the support body 12 and is electrically insulated from the conductive layer 125. The conductive layer 124 has a connection region 124c connected to one electrode of the light-emitting element 31 and a wide portion 124w at the end on the -Z side of the support body 12 that is wider than the connection region 124c. The wide portion 124w is used for electrical connection with the first insulated wire 34a. The conductive layer 125 is formed from the side surface of the support body 12 to the back surface 122.

[0045] The p-side electrode 408 and the n-side electrode 409 of the light-emitting element 31 are connected to the conductive layers 124 and 125 on the light-emitting element mounting surface 121, respectively, via conductive connection layers (or bumps). The wide portion 124w of the conductive layer 124 is electrically connected to the first insulated wire 34a. A portion of the insulating coating of the first insulated wire 34a is removed, and the internal metal wiring is connected to the conductive layer 124. On the back surface 122 of the support 12, the conductive layer 125 is electrically connected to the second insulated wire 34b. A portion of the insulating coating of the second insulated wire 34b is removed, and the internal metal wiring is connected to the conductive layer 125.

[0046] The first insulated wire 34a and the second insulated wire 34b are arranged to sandwich the support 12 and extend in the longitudinal direction (Z direction) of the support 12 so as not to interfere with the light emission of the VCSEL. In the arrangement configuration shown in Figure 8, the second insulated wire 34b connected to the back surface 122 of the support 12 may be extended to near the tip of the support 12 on the +Z side. The first insulated wire 34a and the second insulated wire 34b protruding from the insulating layer 36 in the -Z direction are cooled by contact with a refrigerant. The support 12 may also protrude from the insulating layer 36 at at least one end in the longitudinal direction and be directly cooled by the refrigerant. The conductive layers 124 and 125 formed on the surface of the support 12 also function as a heat sink.

[0047] The VCSEL chip used as the light-emitting element 31 has a side length and height of 200 μm or less, is mounted on the support 12, and is sealed with an insulating layer 36. The overall thickness and width of the light-emitting device 30 are about 0.5 mm, realizing an ultra-compact light-emitting device 30 that can be mounted on a catheter 50. In the example of FIG. 8 , the thickness of the insulating layer 36 is thinner than the thickness of the light-emitting element 31.

[0048] FIG. 11 shows the electrical characteristics and optical output characteristics of the fabricated light-emitting device, and FIG. 12 shows the thermal resistance. The characteristics of this light-emitting device were measured using a sample fabricated according to the first embodiment. The light-emitting element 11 used had a resonator length (length in the Z direction) of 1.5 mm, a width (length in the X direction) of 0.2 mm, and an oscillation wavelength of 640 nm. The support 12 was an AlN substrate with a thickness (length in the Y direction) of 0.1 mm. The mirror was a silver mirror with a bottom surface size (length x width) of 0.3 mm x 0.2 mm and a height of 0.2 mm. The first insulated wire 14a and the second insulated wire 14b were polyurethane copper wires with a diameter of 0.1 mm and a length of 1.5 m. The insulating layer 16 was a polysilazane coating.

[0049] 11, the horizontal axis represents the current value [mA] applied via the insulated wire 14, the left vertical axis represents the optical output [mW], and the right vertical axis represents the voltage [V]. The black marks in the figure represent the current vs. optical output characteristics, and the white marks represent the current vs. voltage characteristics. The optical output increases as the current increases, and an optical power of 30 mW can be obtained with an injection current of 100 mA.

[0050] 12, the horizontal axis represents time (seconds) and the vertical axis represents thermal resistance (K / W). The thermal resistance saturates approximately 0.1 seconds after the light irradiation device is turned on. By cooling the light irradiation device with the refrigerant 51 while it is in operation, heat can be efficiently released from the support 12, the insulated wire 14, and the insulating layer 16, stabilizing the operation of the light irradiation device.

[0051] Although the above description has been based on specific configuration examples, the present disclosure is not limited to the above configuration examples. For example, in the first embodiment, the second insulated wire 14b, which does not interfere with light emission, may be extended from the tip of the support 12 in the +Z direction to function as a heat dissipation member. In the configurations of the first or third embodiment, a light-emitting element and a photodetector such as a photodiode may be disposed on the light-emitting element mounting surface 121 of the support 12 to serve as a biosensor. In the configuration of the third embodiment, instead of mounting two light-emitting elements 31 on the support 12, one light-emitting element 31 and one light-receiving element may be mounted. When using two-core enameled wires as the insulated wires 14 and 34, one metal wiring may be used to supply an electrical signal to the light-emitting element 11 or 31, and the other metal wiring may be used as a wiring to read out a signal output from the photodetector.

[0052] The light irradiation devices 10 (including 10A and 10B), 20, and 30 of the first to third embodiments may be used in combination with an endoscope. The light emitting elements 11 and 31 can be used not only as laser light sources for treatment, but also as sensing light sources and illumination light sources. In either case, they have heat dissipation properties that allow heat from the light emitting elements to be dissipated to the outside, electrical insulation properties sufficient to ensure insulation in a refrigerant, and are effective as light irradiation devices that can be mounted on a catheter. Unlike optical fibers, insulated wires with insulating coatings are highly flexible. Furthermore, a configuration in which the light emitting elements themselves are mounted on the support 12 has excellent integration properties and a wide range of applications for sensors.

[0053] The present invention can be used not only as a light irradiation device inserted into a medical catheter but also in other medical applications, such as sensors that require localized light irradiation in combination with a refrigerant.

[0054] Embodiments of the present disclosure may include, for example, the following configurations: (Item 1) A light irradiation device comprising: a light-emitting element that emits light of a predetermined wavelength; a support on which the light-emitting element is mounted; an insulated wire electrically connected to the light-emitting element; and an insulating layer that integrally covers an outer surface of a structure including the light-emitting element, the support, and the insulated wire. (Item 2) The light irradiation device according to Item 1, further comprising an optical component onto which light emitted from the light-emitting element is incident, and the insulating layer integrally covers the outer surface of the structure including the light-emitting element, the support, the insulated wire, and the optical component. (Item 3) The light irradiation device according to Item 1 or 2, wherein the insulating layer is thinner than the light-emitting element. (Item 4) The light irradiation device according to Item 2, wherein the light-emitting element and the optical component are mounted on a first surface of the support, and a light incident surface of the optical component is inclined with respect to the first surface. (Item 5) The light irradiation device according to Item 2 or 4, wherein the optical component is a reflective member that guides the optical axis of light emitted from the light-emitting element in a direction that intersects with the light-emitting element mounting surface of the support. (Item 6) The light irradiation device according to any one of Items 2, 4, or 5, wherein a predetermined space is provided between the light-emitting surface of the light-emitting element and the light-incident surface of the optical component. (Item 7) The light irradiation device according to any one of Items 1 to 6, wherein the insulated wire includes a first insulated wire electrically connected to a first electrode of the light-emitting element on a side of a first surface of the support on which the light-emitting element is mounted, and a second insulated wire electrically connected to a second electrode of the light-emitting element on a side of a second surface opposite to the first surface. (Item 8) The light irradiation device according to Item 7, wherein the support has a side surface connecting the first surface and the second surface and a conductive layer formed on at least a part of the second surface, and the second insulated wire is connected to the second electrode of the light-emitting element via the conductive layer. (Item 9) The light irradiation device according to any one of Items 2, 4, 5, or 6, wherein the optical component is a mirror. (Item 10) The light irradiation device according to Item 9, wherein the mirror has a reflective layer made of a metal and / or a dielectric. (Item 11) The light irradiation device according to any one of Items 1 to 10, wherein the insulating layer is biocompatible.(Item 12) The light irradiation device according to any one of Items 1 to 11, wherein the insulating layer includes a polysilazane coating. (Item 13) An in-vivo light irradiation assembly, comprising: a catheter; and the light irradiation device according to any one of Items 1 to 12, which is inserted into the catheter; and the inside of the catheter is filled with a refrigerant at least during use.

[0055] This application claims priority based on Japanese Patent Application No. 2023-211661 filed with the Japan Patent Office on December 15, 2023, and includes the entire contents of this Japanese patent application.

[0056] 10, 10A, 10B, 20, 30 Light irradiation device 11, 31 Light emitting element 111 Light emitting surface 12, 12-1, 12-2 Support 121 Light emitting element mounting surface 122 Back surface 124, 125 Conductive layer 14, 24, 34 Insulated wire 14a, 24a, 34a First insulated wire 14b, 24b, 34b Second insulated wire 16, 16A, 16B, 26, 36 Insulating layer 17, 27 Optical component 50 Catheter 51 Refrigerant 100, 200 In-vivo light irradiation assembly

Claims

1. A light irradiation device comprising: a light emitting element that emits light of a predetermined wavelength; a support on which the light emitting element is mounted; an insulated wire electrically connected to the light emitting element; and an insulating layer that integrally covers an outer surface of a structure including the light emitting element, the support, and the insulated wire.

2. The light irradiation device according to claim 1, further comprising an optical component into which light emitted from the light emitting element is incident, and the insulating layer integrally covers an outer surface of a structure including the light emitting element, the support, the insulated electric wire and the optical component.

3. The light irradiation device according to claim 1 or 2, wherein the thickness of the insulating layer is thinner than the thickness of the light emitting element.

4. The light irradiation device according to claim 2, wherein the light emitting element and the optical component are mounted on a first surface of the support, and a light incident surface of the optical component is inclined with respect to the first surface.

5. The light irradiation device according to claim 2 or 4, wherein the optical component is a reflecting member that guides the optical axis of the light emitted from the light-emitting element in a direction intersecting with the light-emitting element mounting surface of the support body.

6. The light irradiation device according to claim 2, 4 or 5, wherein a predetermined space is provided between the light emission surface of the light emitting element and the light incidence surface of the optical component.

7. A light irradiation device as described in any one of claims 1 to 6, wherein the insulated wire includes a first insulated wire electrically connected to a first electrode of the light emitting element on a first surface side of the support on which the light emitting element is mounted, and a second insulated wire electrically connected to a second electrode of the light emitting element on a second surface side opposite to the first surface.

8. The light irradiation device according to claim 7, wherein the support has a side surface connecting the first surface and the second surface and a conductive layer formed on at least a part of the second surface, and the second insulated wire is connected to the second electrode of the light emitting element via the conductive layer.

9. The light irradiation device according to claim 2, 4, 5 or 6, wherein the optical component is a mirror.

10. The light irradiation device according to claim 9, wherein the mirror comprises a reflective layer made of a metal and / or a dielectric.

11. The light irradiation device according to any one of claims 1 to 10, wherein the insulating layer is biocompatible.

12. The light irradiation device according to claim 1, wherein the insulating layer comprises a polysilazane coating.

13. An in vivo light irradiation assembly comprising: a catheter; and a light irradiation device according to any one of claims 1 to 12, which is inserted into said catheter, wherein the inside of said catheter is filled with a refrigerant at least during use.

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