Laser irradiation device

Abstract

Provided is a laser irradiation device capable of efficiently irradiating a laser beam to an irradiation target portion. The present invention is provided with: a laser light source 10 that generates laser light; a fiber-optic probe (20) that transmits the laser light generated by the laser light source (10) and emits the laser light in a direction different from the direction in which the tip side extends; and a light emission unit (22) as a polarization state adjustment unit that adjusts the polarization state of the laser light emitted from the fiber-optic probe (20) and incident on the irradiation target surface.

Description

Technical Field

[0001] The present invention relates to a laser irradiation device used as a medical device, for example. Background Art

[0002] As a previous laser irradiation device, the following device is known, which includes: a laser light source that generates laser light; and an optical fiber probe that transmits the laser light generated in the aforementioned laser light source and emits the transmitted laser light in a direction different from the direction in which the front end side extends (for example, see patent document 1).

[0003] The optical fiber probe of the aforementioned laser irradiation device emits laser light in a direction different from the direction in which the front end side extends. Therefore, for example, when the inner wall surface of a tubular organ such as the esophagus is used as the laser irradiation target surface, the laser can be irradiated to the irradiation target surface without bending the front end side of the optical fiber probe.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2020 / 054674 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] The laser irradiation device irradiates the target surface with a laser beam at an angle from a position at a predetermined angle relative to a direction perpendicular to the target surface. In this case, for example, when a semiconductor laser is used as the light source, the laser beam incident on the target surface becomes an s-polarized light component, with the electric field oscillating perpendicularly to the incident plane, which is a plane encompassing the incident light emitted from the fiber optic probe and incident on the target surface, and the reflected light reflected from the target surface. The s-polarized light component of the laser beam has a higher reflectivity on the target surface than the p-polarized light component. Therefore, laser irradiation may require a longer time in order for the laser beam to fully reach the target area, located inside the target surface and serving as the target for laser irradiation.

[0009] An object of the present invention is to provide a laser irradiation device capable of efficiently irradiating an irradiation target portion with a laser.

[0010] Means for solving problems

[0011] The laser irradiation device involved in the present invention comprises: a laser light source that generates laser light; an optical fiber probe that transmits the laser light generated in the aforementioned laser light source and emits the laser light in a direction different from the direction extending from the front end side; and a polarization state adjustment unit that adjusts the polarization state of the laser light emitted from the aforementioned optical fiber probe and incident on the irradiation object surface.

[0012] Furthermore, in the laser irradiation device according to the present invention, it is preferable that the polarization state adjusting unit adjusts the laser light emitted from the optical fiber probe and incident on the irradiation target surface into a p-polarized light component.

[0013] Furthermore, in the laser irradiation device according to the present invention, preferably, the polarization state adjusting unit emits the laser light toward the outer peripheral side from one side in the vibration direction of the electric field of the laser light propagating through the optical fiber constituting the optical fiber probe.

[0014] Furthermore, in the laser irradiation device according to the present invention, it is preferable that the optical fiber probe has a twisting mechanism for twisting the distal end side relative to the proximal end side.

[0015] Furthermore, in the laser irradiation device according to the present invention, it is preferable that the optical fiber constituting the optical fiber probe is a polarization-maintaining fiber.

[0016] Furthermore, in the laser irradiation device according to the present invention, it is preferable that the optical fiber constituting the optical fiber probe is a single-mode optical fiber.

[0017] Furthermore, in the laser irradiation device according to the present invention, it is preferable that the polarization state adjusting section is a half-wavelength plate.

[0018] Furthermore, the laser irradiation device according to the present invention preferably includes a polarizer disposed between the laser light source and the half-wavelength plate and transmitting a predetermined polarized light component of the laser light generated by the laser light source.

[0019] Furthermore, in the laser irradiation device according to the present invention, it is preferable that the polarization state adjusting section is a non-polarization section that non-polarizes the laser light generated by the laser light source.

[0020] Furthermore, in the laser irradiation device according to the present invention, it is preferable that the non-polarization section is formed by spirally winding an optical fiber constituting the optical fiber probe around a rod-shaped member.

[0021] Effects of the Invention

[0022] According to the present invention, by adjusting the polarization state of the laser light irradiated on the irradiation target surface, reflection of the laser light on the irradiation target surface can be suppressed, and thus the irradiation target portion can be efficiently irradiated with the laser light. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] [ Figure 1 ] Figure 1 (a) Figure 1 (b) and Figure 1 (c) is a schematic diagram of the distal end side of the optical fiber probe according to the first embodiment of the present invention.

[0024] [ Figure 2 ] Figure 2 This is a schematic diagram of a semiconductor laser according to a first embodiment of the present invention.

[0025] [ Figure 3 ] Figure 3 This is a schematic diagram of the optical fiber probe according to the first embodiment of the present invention.

[0026] [ Figure 4 ] Figure 4 (a) and Figure 4 (b) is a diagram illustrating s-polarized light and p-polarized light according to the first embodiment of the present invention.

[0027] [ Figure 5 ] Figure 5 Graph showing the relationship between the incident angle and reflectivity of each of s-polarized light and p-polarized light according to the first embodiment of the present invention.

[0028] [ Figure 6 ] Figure 6 It is a diagram for explaining a laser irradiation device according to a second embodiment of the present invention.

[0029] [ Figure 7 ] Figure 7 It is a diagram illustrating a non-polarizing unit according to a third embodiment of the present invention. DETAILED DESCRIPTION

[0030] <First embodiment>

[0031] Figures 1 to 5 A first embodiment of the present invention will be described. Figure 1 (a) Figure 1 (b) and Figure 1 (c) is a schematic diagram of the front end side of the optical fiber probe. Figure 2 This is a schematic diagram of a semiconductor laser. Figure 3 This is a schematic diagram of a fiber optic probe. Figure 4 (a) and Figure 4 (b) is a diagram illustrating s-polarized light and p-polarized light. Figure 5 Graphs showing the relationship between the incident angle and reflectivity for s-polarized light and p-polarized light, respectively.

[0032] The laser irradiation device 1 of this embodiment is used, for example, in photoimmunotherapy, one of the treatment methods for cancer. Photoimmunotherapy treats cancer by administering a drug containing an antibody that binds to cancer cells and a substance that reacts with light to the human body, and then irradiating the drug bound to the cancer cells with laser light to destroy the cancer cells.

[0033] The laser irradiation device 1 includes: Figure 2The laser light source 10 for generating laser light as shown; and Figure 1 The optical fiber probe 20 shown transmits the laser light generated in the laser light source 10 and emits the laser light in a direction different from the direction in which the distal end side extends.

[0034] The laser light source 10 includes a semiconductor laser 11. When power is supplied to the semiconductor laser 11, laser oscillation occurs and laser light is generated. The semiconductor laser 11 has a so-called double heterostructure, in which an active layer 11c made of a semiconductor having a material different from that of the p-type cladding layer 11a and the n-type cladding layer 11b is arranged between a p-type cladding layer 11a made of a p-type semiconductor and an n-type cladding layer 11b made of an n-type semiconductor. Figure 2 As shown by arrow E in FIG, semiconductor laser 11 generates linearly polarized laser light due to electric field oscillation along the direction in which active layer 11c extends. Laser light source 10 generates red laser light having a wavelength of, for example, 670 nm to 700 nm.

[0035] like Figure 1 As shown, the optical fiber probe 20 has: a light transmission part 21 for transmitting the laser light generated in the laser light source 10; and a light emitting part 22, which causes the laser light transmitted in the light transmission part 21 to be emitted at a predetermined angle relative to the direction extending along the front end side of the light transmission part 21.

[0036] The light transmission unit 21 includes an optical fiber 20a constituting the optical fiber probe 20, and is formed by covering a core having a high refractive index with a cladding having a low refractive index. Here, the optical fiber 20a constituting the optical fiber probe 20 is a polarization-maintaining fiber.

[0037] The light emitting portion 22 is provided at the front end side of the optical fiber probe 20. The light emitting portion 22 may be Figure 1 (a) and Figure 1 As shown in (b) of FIG. 1 , light emitting components 22a and 22b are installed at the front end of the optical fiber 20a constituting the optical fiber probe 20, or as shown in FIG. Figure 1 The portion shown in (c) is formed at the front end of the optical fiber 20a.

[0038] Figure 1 The light emitting portion 22 shown in (a) is a light emitting member 22a including a ball lens 22a1 for refracting light and a holding member 22a2 for holding the ball lens 22a1 at the front end portion of the optical fiber 20a.

[0039] in addition, Figure 1 The light emitting portion 22 shown in (b) is a light emitting member 22b having a gold-deposited mirror 22b1 for reflecting light and a holding member 22b2 for holding the mirror 22b1 at the distal end of the optical fiber 20a.

[0040] also, Figure 1 The light emitting portion 22 shown in (c) is configured such that the distal end portion of the optical fiber 20a is formed with an inclined surface 20a1 that is inclined relative to the direction in which the optical fiber 20a extends and a direction perpendicular to the direction in which the optical fiber 20a extends. Laser light propagating through the optical fiber 20a is reflected by the inclined surface 20a1 and is emitted at an angle of a predetermined angle relative to the direction in which the distal end of the optical fiber 20a extends.

[0041] Here, Figure 1 (a) Figure 1 (b) and Figure 1 The light emitting parts 22 shown in (c) in FIG. 1 and FIG. 2 respectively constitute polarization state adjusting parts. Figure 3 As shown, the polarization state adjustment unit of this embodiment causes laser light (arrow L) to be emitted from the optical fiber 20a toward the outer periphery in the direction of the laser light's electric field vibration (arrow E). When the laser light is emitted from the light emitting unit 22, the polarization state of the laser light can be confirmed while monitoring the reflected light reflected from the irradiated surface S. Alternatively, the polarization state of the laser light emitted from the light emitting unit 22 can be confirmed using a polarimeter consisting of a polarizer and a photodetector. In this case, adjustment is performed so that the ratio of the p-polarized light component to the s-polarized light component is greater than 1.

[0042] Furthermore, the optical fiber probe 20 includes a twisting mechanism (not shown) that twists the distal end side relative to the proximal end side around the axial direction.

[0043] When the laser irradiation device 1 configured as described above is used for photoimmunotherapy, the laser irradiation device 1 irradiates a drug that has reached cancer cells with the distal end of the optical fiber probe 20 inserted into the human body.

[0044] At this time, the linearly polarized laser light generated in the laser light source 10 propagates in the optical fiber probe 20 and is emitted from the light emitting portion 22 located at the front end of the optical fiber probe 20. The laser light emitted from the light emitting portion 22 is emitted from one side of the vibration direction of the electric field of the laser light in the optical fiber probe 20 toward the outer peripheral side. Figure 3 As shown by arrow T, the laser light emitted from the light emitting portion 22 is twisted at the distal end relative to the proximal end of the optical fiber probe 20 by the twisting mechanism, thereby irradiating the irradiation target portion A, which is the target position of the irradiation laser light.

[0045] Here, the laser light irradiated on the irradiation target portion A is incident obliquely with respect to the irradiation target surface S on the outer surface side of the irradiation target portion A. Figure 4 (a) and Figure 4As shown in (b) in FIG. 1 , with respect to the laser beam irradiated on the irradiation target surface S, there are cases where the vibration direction E of the electric field becomes a component of s-polarized light perpendicular to the incident surface, which is a plane including the incident light incident on the irradiation target surface S and the reflected light reflected on the irradiation target surface S, and cases where the vibration direction E of the electric field becomes a component of p-polarized light parallel to the incident surface. In this embodiment, the laser beam irradiated on the irradiation target surface S becomes a component of p-polarized light parallel to the incident surface. Figure 5 As shown, the reflectivity of the p-polarized light component of the laser light is lower than when the s-polarized light component is incident on the irradiation target surface S. Therefore, by irradiating the irradiation target surface S with the p-polarized light component of the laser light, the irradiation target portion A can be more efficiently reached than when the irradiation target surface S is irradiated with the s-polarized light component. The case where the laser light irradiating the irradiation target surface S is the p-polarized light component refers to the polarization state when the reflected light component is at a minimum value when the laser light is irradiated on the irradiation target surface S.

[0046] As described above, the laser irradiation device 1 according to this embodiment includes: a laser light source 10 that generates laser light; an optical fiber probe 20 that transmits the laser light generated in the laser light source 10 and emits the laser light in a direction different from the direction in which the front end side extends; and a light emitting portion 22 that serves as a polarization state adjusting portion that adjusts the polarization state of the laser light emitted from the optical fiber probe 20 and incident on the irradiation object surface.

[0047] Thus, by adjusting the polarization state of the laser light irradiated on the irradiation target surface S, reflection of the laser light on the irradiation target surface S can be suppressed, so that the irradiation target portion A can be efficiently irradiated with the laser light.

[0048] Furthermore, it is preferable that the light emitting unit 22 as the polarization state adjusting unit adjusts the laser light emitted from the optical fiber probe 20 and incident on the irradiation target surface S into a p-polarized light component.

[0049] This further reduces the reflection of the laser light on the irradiation target surface S, and thus the irradiation target portion A can be irradiated with the laser light more efficiently.

[0050] Furthermore, it is preferable that the light emitting unit 22 as the polarization state adjusting unit emits the laser light toward the outer peripheral side from one side in the vibration direction of the electric field of the laser light propagating through the optical fiber 20 a constituting the optical fiber probe 20 .

[0051] Thus, by irradiating the irradiation target portion A with the laser light emitted from the light emitting portion 22 , the laser light incident on the irradiation target surface S can be easily converted into a p-polarized light component.

[0052] Furthermore, it is preferable that the optical fiber probe 20 has a twisting mechanism for twisting the distal end side relative to the proximal end side.

[0053] Thus, the laser beam obliquely irradiated from the distal end side of the optical fiber probe 20 can be reliably irradiated toward the irradiation target portion A, and thus the operation of irradiating the irradiation target portion A with the laser beam can be efficiently performed.

[0054] Furthermore, it is preferable that the optical fiber 20 a constituting the optical fiber probe 20 is a polarization-maintaining fiber.

[0055] Thus, even when an external force acts on the optical fiber 20 a , the polarization state of the transmitted laser light can be maintained, and thus the laser light emitted from the optical fiber probe 20 can be made into a desired polarization state.

[0056] It should be noted that, in the aforementioned embodiment, an example is shown in which a polarization-maintaining fiber is used as the optical fiber 20 a constituting the optical fiber probe 20 , but the present invention is not limited thereto.

[0057] The optical fiber 20 a constituting the optical fiber probe 20 may be a single-mode optical fiber.

[0058] This can suppress dispersion of the transmitted laser light due to refraction and reflection, and thus maintain the polarization state of the laser light emitted from the optical fiber probe.

[0059] <Second embodiment>

[0060] Figure 6 The second embodiment of the present invention is shown, and the diagram is for explaining a laser irradiation device.

[0061] The laser irradiation device 1 of the present embodiment includes a polarizer 30 and a half-wavelength plate 40 as a polarization state adjusting unit disposed between a laser light source 10 and an optical fiber probe 20 .

[0062] The polarizer 30 transmits only polarized light components of an electric field vibrating in the direction in which the active layer 11 c of the semiconductor laser 11 of the laser light source 10 extends, and reflects polarized light components vibrating in other directions.

[0063] The half-wave plate 40 generates a phase difference of half the wavelength in the incident light, thereby rotating the vibration direction of the laser light by 90 degrees.

[0064] In this embodiment, the laser light propagating through the optical fiber 20a of the optical fiber probe 20 is rotated 90 degrees relative to the vibration direction of the electric field of the laser light generated by the laser light source 10 by the half-wave plate 40. Therefore, the light emitting portion 22 of this embodiment is also configured to emit laser light from a position rotated 90 degrees relative to the optical fiber 20a in the first embodiment.

[0065] In the laser irradiation device 1 configured as described above, the laser light generated by the laser light source 10 transmits only the linearly polarized component through the polarizer 30. The linearly polarized component transmitted through the polarizer 30 is then rotated 90 degrees in its vibration direction by the half-wave plate 40 and emitted obliquely from the light exit section 22. Consequently, as in the previously described embodiment, the laser light emitted from the light exit section 22 and irradiated onto the irradiation target surface S becomes a p-polarized component whose electric field vibration direction is parallel to the plane of incidence. Therefore, by irradiating the irradiation target surface S with the p-polarized component of the laser light, the irradiation target surface A can be more efficiently reached than when the irradiation target surface S is irradiated with the s-polarized component.

[0066] As described above, according to the laser irradiation device 1 of this embodiment, by adjusting the polarization state of the laser irradiated on the irradiation target surface A, the reflection of the laser on the irradiation target surface S can be suppressed, thereby efficiently irradiating the irradiation target portion A with laser.

[0067] In addition, it is preferable that the polarization state adjusting unit is the half-wavelength plate 40 .

[0068] Thus, the oscillation direction of the electric field of the laser light generated in the laser light source 10 can be rotated 90 degrees and emitted from the light emitting portion 22 of the optical fiber probe 20 , thereby easily converting the laser light irradiated on the irradiation target surface S into a p-polarized light component.

[0069] Furthermore, it is preferable to provide a polarizer 30 that is disposed between the laser light source 10 and the half-wavelength plate 40 and transmits a predetermined polarized light component of the laser light generated in the laser light source 10 .

[0070] In this way, only the component of linearly polarized light in the vibration direction of the electric field of the laser can be transmitted, and the component of linearly polarized light can be rotated using a 1 / 2 wavelength plate, thereby further suppressing the reflection of the laser on the irradiation object surface S and enabling the laser irradiation of the irradiation object part A to be performed more efficiently.

[0071] <Third embodiment>

[0072] Figure 7 This figure shows a third embodiment of the present invention and is a diagram for explaining a non-polarizing portion.

[0073] The polarization state adjusting unit of the laser irradiation device 1 of the present embodiment is a non-polarization unit 50 that depolarizes the laser light generated by the laser light source 10 , and is configured in the light transmission unit 21 of the optical fiber probe 20 .

[0074] The non-polarization section 50 is formed by winding the optical fiber 20 a around a rod-shaped member 51 having a groove extending in a spiral shape formed on the outer circumference thereof.

[0075] In the laser irradiation device 1 configured as described above, laser light generated by the laser light source 10 propagates through the optical fiber 20a of the optical fiber probe 20. The oscillation direction of the electric field is changed to various directions in the non-polarization section 50, thereby depolarizing the laser light. Consequently, the depolarized laser light is irradiated onto the irradiation target surface S, enabling the laser light to reach the irradiation target portion A more efficiently than when the irradiation target surface S is irradiated with an s-polarized light component.

[0076] As described above, according to the laser irradiation device 1 of this embodiment, by adjusting the polarization state of the laser irradiated on the irradiation target surface S, the reflection of the laser on the irradiation target surface S can be suppressed, thereby efficiently irradiating the irradiation target part A with laser.

[0077] Furthermore, the polarization state adjusting unit is preferably a non-polarization unit 50 that non-polarizes the laser light generated in the laser light source 10 .

[0078] Thus, by depolarizing the linearly polarized laser light generated in the laser light source 10 , the laser light can be reliably made to reach the irradiation target portion A.

[0079] In addition, the non-polarization unit 50 is preferably formed by spirally winding the optical fiber 20a constituting the optical fiber probe 20 around the rod-shaped member 51. When the maximum amount of transmitted light when the polarization is rotated is defined as P max , set the minimum transmitted light amount to P min In the case of polarization extinction ratio R e (dB) is defined as R e =10log(P max / P min When the optical fiber 20a is wound around the rod-shaped member 51, the polarization extinction ratio R e The number of windings and the degree of twisting of the optical fiber 20a may be adjusted so that the (dB) becomes 20 dB or less.

[0080] Thus, since the optical fiber 20a is wound around the rod-shaped member 51 with a simple structure and a small dedicated space, it is possible to reduce the manufacturing cost and suppress the size increase of the device.

[0081] It should be noted that, while the third embodiment described above shows the non-polarization section 50 formed by winding the optical fiber 20a around the rod-shaped member 51, the present invention is not limited thereto. As long as the laser light emitted from the optical fiber probe 20 can be depolarized, the non-polarization section may be formed by forming a plurality of curved portions in the optical fiber 20a, for example, in a zigzag shape.

[0082] In addition, in the above-mentioned first to third embodiments, the laser irradiation device is applied to photoimmunotherapy, but is not limited to this and can be used for photodynamic therapy, catheter ablation therapy, optical coherence tomography (OCT), etc.

[0083] Description of Reference Numerals

[0084] 1 Laser irradiation device

[0085] 10 Laser light source

[0086] 20 Fiber Optic Probes

[0087] 20a optical fiber

[0088] 21 Optical Transmission Department

[0089] 22 Light exit part

[0090] 30 Polarizing filter

[0091] 40 1 / 2 wavelength plate

[0092] 50 Non-polarization part

[0093] 51 Rod-shaped parts

Claims

1. A laser irradiation device comprising: a laser light source for generating laser light; an optical fiber probe that transmits the laser light generated in the laser light source and emits the laser light in a direction different from a direction in which the distal end side extends; and A polarization state adjusting unit adjusts the polarization state of the laser light emitted from the optical fiber probe and incident on an irradiation target surface.

2. The laser irradiation device according to claim 1, wherein The polarization state adjusting unit adjusts the laser light emitted from the optical fiber probe and incident on the irradiation target surface into a p-polarized light component.

3. The laser irradiation device according to claim 1, wherein The polarization state adjusting unit causes the laser light to be emitted toward the outer peripheral side from one side in the vibration direction of the electric field of the laser light propagating through the optical fiber constituting the optical fiber probe.

4. The laser irradiation device according to claim 3, wherein The optical fiber probe includes a twisting mechanism for twisting the distal end side relative to the proximal end side.

5. The laser irradiation device according to claim 2, wherein The optical fiber constituting the optical fiber probe is a polarization-maintaining optical fiber.

6. The laser irradiation device according to claim 2, wherein The optical fiber constituting the optical fiber probe is a single-mode optical fiber.

7. The laser irradiation device according to claim 2, wherein: The polarization state adjusting unit is a half-wavelength plate. 8 . The laser irradiation device according to claim 7 , further comprising a polarizer disposed between the laser light source and the half-wavelength plate and transmitting a predetermined polarized light component of the laser light generated by the laser light source.

9. The laser irradiation device according to claim 1, wherein The polarization state adjusting section is a non-polarization section that non-polarizes the laser light generated by the laser light source.

10. The laser irradiation device according to claim 9, wherein The non-polarization unit is formed by spirally winding the optical fiber constituting the optical fiber probe around a rod-shaped member.

Images