JP2013141581A - Laser beam thermal converter using fiber, heating device, and manufacturing method for laser beam thermal converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam thermal converter using fiber, the converter converting a laser beam into thermal energy at high efficiency at the leading end part of the fiber even when the laser beam is output low.SOLUTION: The laser beam thermal converter 100 using fiber comprises optical fiber 1 including: a core 2 containing SiOas its material that is a light transmitter when the temperature of the material is equal to or below a prescribed temperature and is a light absorber increased in laser beam absorption when the temperature increases beyond the prescribed temperature; and a clad 3. The optical fiber 1 has at its leading end part 1a a surface layer in which powder of, for example, TiO, serving as light-loss material, are dispersed. In the optical fiber 1, when a laser beam is made incident on the leading end part 1a via the core 2, the temperature of the leading end part 1a becomes higher than the prescribed temperature due to light loss by virtue of the light loss material of the surface layer. When the SiOof the leading end part 1a serving as the light absorber absorbs a laser beam, the leading end part 1a emits light at a high temperature and in a melted state.

Description

  The present invention relates to a laser photothermal conversion device, a heating device, and a method for manufacturing a laser photothermal conversion device using a fiber.

  There is known an apparatus that emits laser light from a distal end portion of an optical fiber toward a living tissue and performs incision or transpiration of the living tissue with the laser light.

  Patent Document 1 discloses a laser beam in which a surface layer containing absorbing powder that absorbs pulsed laser light and light scattering powder having a refractive index higher than that of the transmitting member is provided on the surface of the laser beam transmitting member. An apparatus using a transparent body is described. In the apparatus using the transmission body of the pulse laser beam described in Patent Document 1, the pulse laser beam is scattered by the light scattering powder on the surface layer, and the pulse laser beam is emitted from the entire surface layer at various angles. In this apparatus, the surface layer of the transmission member is about 300 ° C.

JP-A-2-159269

  However, an apparatus that performs incision or transpiration of a living tissue using laser light emitted from the tip of the optical fiber requires relatively high-power laser light.

  Further, as described above, in the apparatus using the laser light transmitting body described in Patent Document 1, the surface layer portion of the transmitting member is about 300 ° C. However, there is a demand for an apparatus that has a fiber tip that is hotter than that and that can evaporate living tissue in a short time.

  The present invention has been made in view of the above-described problems, and even with a low-power laser beam, the laser beam can be converted into thermal energy with high efficiency at a fiber tip with a simple structure. Providing a laser photothermal conversion device using a fiber, providing a heating device equipped with a laser photothermal conversion device, and providing a method for producing a laser photothermal conversion device capable of easily producing the laser photothermal conversion device The purpose is to do.

  A laser light-to-heat converter using the fiber of the present invention is a light transmissive body at a specified temperature or lower, and includes a core including a forming material that becomes a light absorber having a higher absorbance of the laser light as the temperature becomes higher than the specified temperature, and a clad. The fiber has a surface layer obtained by diffusing a powder of a light loss material at a tip portion of the fiber, and when the laser beam is incident on the tip portion through the core, the fiber Due to light loss due to the light-loss material on the surface layer, the tip portion becomes a temperature higher than the specified temperature, and the forming material of the tip portion serving as the light absorber absorbs the laser light, thereby the tip portion. Emits light at a high temperature and in a molten state.

  The heating device of the present invention is configured so that the laser light-to-heat conversion device using the fiber according to the present invention, a laser light generating unit that emits laser light to the fiber, and the tip of the fiber emit light at a high temperature and in a molten state. And a control unit for controlling the emission of the laser beam by the laser beam generation unit.

  The method for producing a laser photothermal conversion device of the present invention is a method for producing a laser photothermal conversion device using the fiber according to the present invention, wherein the laser photothermal conversion device is a light transmitting body at a specified temperature or lower, The tip of the fiber comprising a core including a forming material that becomes a light absorber having a higher absorbance of laser light as the temperature becomes higher than the specified temperature, and a cladding are brought into contact with a contacted body containing a powder of a light loss body. In a state where the laser beam is emitted from the tip of the fiber, the forming material of the fiber tip is heated and melted, and the laser beam emission is stopped to stop the fiber tip. And a step of forming a surface layer in which the optical loss material is diffused at the tip of the fiber.

  According to the present invention, there is provided a laser light-to-heat conversion device using a fiber, which can convert laser light into heat energy with high efficiency even at low output laser light with a simple structure at the tip of the fiber. Can be provided. Moreover, a heating apparatus provided with a laser photothermal conversion apparatus can be provided. Moreover, the manufacturing method of the laser photothermal conversion apparatus which can manufacture the said laser photothermal conversion apparatus easily can be provided.

Schematic which shows an example of the heating apparatus which has a laser photothermal conversion apparatus concerning embodiment of this invention. The enlarged view of the front-end | tip part of the fiber as a laser photothermal conversion apparatus concerning embodiment of this invention. The figure which shows an example of the emission spectrum at the time of light emission of the front-end | tip of the fiber of the laser photothermal conversion apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the manufacturing method of the laser photothermal conversion apparatus which concerns on embodiment of this invention, (a) is sectional drawing of the front-end | tip part of an optical fiber, (b) removes part of the coating | cover (protective layer) of a front-end | tip part. (C) is a cross-sectional view of a sheet including an optical loss body and an optical fiber, (d) is a diagram showing an example when laser light is irradiated in a contact state between the sheet and the optical fiber tip, (e) FIG. 3 is a diagram showing an example of a cross section of an optical fiber in which a substantially hemispherical portion is formed at the tip. The figure which shows an example of the electron micrograph of the optical fiber front-end | tip part of the laser photothermal conversion apparatus which concerns on embodiment of this invention. It is a figure which shows an example of operation | movement of the heating apparatus which concerns on embodiment of this invention, (a) is a figure which shows an example of the electric current value input into the semiconductor laser element of a laser beam generator, (b) is a laser beam generation The figure which shows an example of the intensity | strength of the laser beam output from an apparatus, (c) is a figure which shows an example of the emitted light intensity of a fiber front-end | tip part. It is a figure which shows the other example of operation | movement of the heating apparatus which concerns on embodiment of this invention, (a) is a figure which shows an example of the electric current value input into the semiconductor laser element of a laser beam generator, (b) is a fiber The figure which shows an example of the emitted light intensity of a front-end | tip part. It is a figure which shows an example of operation | movement of the laser photothermal conversion apparatus which concerns on embodiment of this invention, (a) is a figure which shows an example of the electric current value input into the semiconductor laser element of a laser beam generator, (b) is a fiber The figure which shows an example of the emitted light intensity of the fiber tip part at the time of arrange | positioning a front-end | tip part in air, (c) is a figure which shows an example of the emitted light intensity at the time of arrange | positioning a fiber front-end | tip part in a hyaluronic acid solution, (d) FIG. 4 is a diagram showing an example of light emission intensity when the fiber tip is disposed in physiological saline. The figure which shows an example of the intensity | strength of the laser beam permeate | transmitted from the fiber front-end | tip part of a high temperature state at the time of operation | movement of the heating apparatus which concerns on embodiment of this invention.

  A heating apparatus 200 having a laser photothermal conversion apparatus 100 using a fiber according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating an example of a heating device 200 including a laser photothermal conversion device 100 according to an embodiment of the present invention. FIG. 2 is an enlarged view of the distal end portion 1 a of the optical fiber 1 as the laser photothermal conversion device 100.

  The laser photothermal conversion device 100 includes an optical fiber (fiber) 1 as shown in FIGS. 1 and 2. The heating device 200 includes a laser photothermal conversion device 100 and a laser light generation device 10 connected to the end of the optical fiber 1 of the laser photothermal conversion device 100.

<Optical fiber 1>
The optical fiber 1 includes a core 2 as a light transmitting body, a clad 3 formed on the outer periphery of the core 2 and having a refractive index slightly smaller than the core 2, and a coating 4 formed on the outer periphery of the clad 3. The core 2, the clad 3, and the coating 4 are formed concentrically.

The core 2 is formed of a material having a high refractive index such as quartz (SiO ₂ ). The clad 3 is formed of a material such as quartz or resin, and has a refractive index lower than the core 2 by about 0.2 to 1%. The coating 4 is formed of a resin material such as a fluororesin and protects the core 2 and the clad 3. In the present embodiment, the core 2 is made of quartz (SiO ₂ ), the cladding 3 is made of a hard resin material, and the coating 4 is made of a resin material containing fluorine.

  As shown in FIG. 1 and FIG. 2, the optical fiber 1 has a substantially hemispherical portion formed at the tip 1a. Light scattering powder that scatters laser light at the tip 1a and light absorption that absorbs laser light. It has the surface layer which diffused the powder of light loss bodies 6, such as powder.

Front-end 1a of the optical fiber 1, as described later, when the laser beam incident, and SiO ₂ is melted in a high temperature state, the light loss material 6 is in a state of being diffused into SiO _2, it emits light. When the incidence of the laser beam is stopped (when the laser beam is not incident), the temperature of the distal end portion 1a of the optical fiber 1 decreases, the distal end portion 1a solidifies in a substantially hemispherical shape, and the optical loss body 6 is formed in the surface layer. More specifically, it is diffused and buried, and more specifically, the SiO ₂ at the tip 1 a becomes a point defect state due to the diffusion of the optical loss body 6.

As the light loss body 6, TiO ₂ (titanium oxide) or the like can be employed. The average particle size (particle diameter) of the TiO ₂ powder is about 1 μm to 50 μm, preferably about 10 μm to 50 μm. The powder of TiO ₂ (molecular weight 79.88, rutile crystal structure) is white and scatters or absorbs light depending on the wavelength of light. As optical loss body 6, it may be employed a powder of TiO ₂ of the anatase type crystal structure.

In the optical fiber 1 of the present embodiment, the core 2 has a diameter of about 50 μm, the outer diameter of the cladding 3 is about 300 μm, and the tip 1 a of the optical fiber 1 that emits light at a high temperature and in a molten state has a diameter of about 300 μm. Is about 200 μm in length. Further, in a molten state, titanium oxide (TiO ₂ ) is diffused from the surface of the tip of the optical fiber 1 to the inside by about 1 μm to 200 μm.

<Laser light generator 10>
As shown in FIG. 1, the laser light generation device 10 includes a laser light generation unit 11, an operation input unit 12, a display unit 13, a storage unit 14, and a control unit (CPU) 15.

  The laser beam generator 11 emits laser beam (L) under the control of the controller 15 and outputs the laser beam to the optical fiber 1.

  As the laser light generator 11, a semiconductor laser element, a solid laser device, a fiber laser device, or the like can be employed. The laser beam generator 11 according to this embodiment includes a semiconductor laser element. This semiconductor laser element outputs laser light having a predetermined wavelength according to a current input from a power supply circuit (not shown). The laser beam generator 11 is a CW mode that emits laser beam continuously, or a repeat mode that repeats laser oscillation (on time) and oscillation stop (off time) intermittently at a constant set time and constant output intensity. For example, various laser output modes may be provided. The repeat mode can be easily realized, for example, by intermittently inputting a drive current having a predetermined current value to the semiconductor laser element.

  In the present embodiment, the laser beam generator 11 can output in a wavelength of 980 nm, an output of about 4 to 30 W, a CW mode, and a repeat mode. The laser light generator 11 can output a laser in a repeat mode so as to be adjustable between an on time of 1 ms to 1000 ms and an off time of 1 ms to 1000 ms.

  The operation input unit 12 includes a foot switch, an operation button, and the like, and outputs a signal corresponding to a user operation to the control unit 15. The control unit 15 performs processing for controlling the output level, on-time, off-time, and the like of the laser light emitted from the laser light generation unit 11 in accordance with the operation of the operation input unit 12.

The display unit 13 performs display according to the operation according to the present invention under the control of the control unit 15.
The storage unit 14 includes a semiconductor storage device such as a RAM and a ROM, a magnetic disk storage device such as a hard disk drive, and the like, and stores programs, data, and the like for realizing the functions according to the present invention. The storage unit 14 is also used as a work area for program execution by the control unit 15.

  The control unit 15 comprehensively controls each component of the laser photothermal conversion device 100. Moreover, the control part 15 implement | achieves the function based on this invention in the laser photothermal conversion apparatus 100 by running the program memorize | stored in the memory | storage part 14. FIG.

  In addition, the control unit 15 performs a process of emitting laser light from the laser light generation unit 11, and causes the distal end portion 1a of the optical fiber 1 to be in a high-temperature and molten state, and emits laser light that emits light from the distal end portion 1a. The process which controls the laser beam generation part 11 is performed. Detailed processing of the control unit 15 will be described later.

<Operation of Heating Device 200>
Next, operation | movement of the heating apparatus 200 which concerns on embodiment of this invention is demonstrated.

When the operation input unit 12 is operated, the control unit 15 performs a process of emitting laser light from the laser light generation unit 11. As shown in FIGS. 1 and 2, when laser light is incident on the end of the optical fiber 1, it propagates through the core 2, and the SiO ₂ is in a point-defect state by the optical loss body 6 diffused in the front end 1 a of the optical fiber 1. In the formed region, the tip 1a becomes high temperature due to repetition of reflection and absorption. Therefore, SiO ₂ becomes high optical loss material 6 near the tip 1a.

SiO ₂ which is a material for forming the core 2 has a low absorbance at room temperature (a temperature lower than a specified temperature), and is a light transmitting material with respect to laser light having a wavelength of 980 nm, for example. ) It has a property that the absorbance rapidly increases at the above temperature. For this reason, SiO ₂ in the vicinity of the light loss body 6 in a high temperature state becomes a light absorber with respect to laser light having a wavelength of, for example, 980 nm when the temperature is about 1050 ° C. or higher. This high-temperature SiO ₂ absorbs laser light and converts the energy of the laser light into heat energy with high efficiency. Due to this thermal energy, the temperature in the high temperature region of the tip 1a further increases, and the absorbance of SiO ₂ further increases. The fiber tip 1a emits light according to its temperature.

  In the heating apparatus 200 according to the present embodiment, the control unit 15 outputs the laser beam so that the fiber tip 1a is in a high temperature state (temperature is about 4000K), the tip 1a is melted, and the tip 1a emits light. Control. The fiber tip 1a in a high temperature state of about 4000K has a melted state of the core 2 and the clad 3, and emits light by heat energy.

As shown in FIGS. 1 and 2, in a state where the fiber tip 1a emits light at a high temperature, heat is transferred from the fiber tip 1a to a substance (biological tissue, liquid, gas, etc.) around the fiber tip 1a. Energy can be transmitted by conduction, heat radiation, etc., and surrounding materials can be heated to a high temperature in a short time.
In addition, a high-temperature (about 4000 K) plasma state is formed around the distal end portion 1a of the optical fiber 1 of the laser photothermal conversion device 100 according to the embodiment of the present invention. Specifically, the tip 1a of the optical fiber 1 is in a high temperature and light emitting state of about 4000 K, and is in a state of being burned by being combined with surrounding oxygen, oxygen of SiO ₂ of the fiber itself, and the like. Further, oxygen, carbon, and the like in a high temperature state are ionized at the distal end portion 1a and the peripheral portion thereof to be in a plasma state (low density plasma). This phenomenon is called thermal plasma.

  When the laser light (L) from the laser light generator 10 enters the optical fiber 1, the laser light propagates through the core 2 of the optical fiber 1, and light scattering, light absorption, etc. by the light loss body 6 at the tip 1a of the optical fiber 1 is performed. It is converted into thermal energy due to light loss. And the front-end | tip part 1a of the optical fiber 1 light-emits white in the state melt | dissolved at the high temperature of about 4000K, and the light is radiated | emitted to substantially all directions.

  FIG. 3 is a diagram showing an example of an emission spectrum at the time of light emission of the fiber tip 1a of the laser photothermal conversion device 100 according to the embodiment of the present invention. The inventor of the present application performed spectrum analysis on the light emitted from the fiber tip 1a of the laser photothermal conversion device 100 according to the embodiment of the present invention using a spectroscope.

In the heating apparatus 200 according to the embodiment of the present invention, for example, when laser light having a wavelength of 980 nm is incident on the optical fiber 1, the distal end portion 1 a of the optical fiber 1 is in a high temperature and melted state and emits light. As shown in FIG. 3, the spectrum of light emitted from the tip 1a has the highest intensity in the visible light region, and has a broad emission intensity over the infrared region, visible light region, and ultraviolet region. . In the infrared region and the ultraviolet region, the emission intensity is lower than that in the visible light region.
In addition, based on the emission spectrum, the light temperature calculated using the distribution formula of the spectral radiance due to black body radiation was about 4000K.

<Method for Manufacturing Laser Photothermal Conversion Device 100>
4A and 4B are diagrams illustrating an example of a method for manufacturing the laser photothermal conversion device 100 according to the embodiment of the present invention. FIG. 4A is a cross-sectional view of the distal end portion 1a of the optical fiber 1, and FIG. 4C is a cross-sectional view of the optical fiber 1 from which the coating (protective layer) 4 of the portion 1a is partially removed, FIG. 4C is a cross-sectional view of the sheet 9 including the optical loss body 6 and the optical fiber 1, and FIG. The figure which shows an example when a laser beam (L) is irradiated in the contact state of the fiber front-end | tip part 1a, FIG.4 (e) is a figure which shows an example of the cross section of the optical fiber 1 in which the substantially hemispherical part was formed in the front-end | tip part 1a. Indicates.

  As shown in FIG. 4A, the optical fiber 1 has a core 2, a clad 3, and a coating 4 formed on the outer periphery.

  As shown in FIG. 4B, only the coating 4 about several centimeters away from the tip of the optical fiber 1 is removed with a jig or the like.

Next, as shown in FIG. 4C, a sheet 9 for fiber tip processing is prepared. The sheet 9 is formed of various materials such as paper, resin, and metal. Further, the sheet 9 has a region 9a containing the powder of the optical loss body 6 such as TiO ₂ or MnO ₂ . This region 9a is set to a region that is the same as or larger than the diameter of the clad 3. The entire sheet 9 may contain the light loss body 6 powder.

The average particle size (particle size) of TiO ₂ is about 1 μm to 50 μm. For example, the average particle diameter of the TiO ₂ powder is set to a predetermined diameter (about 50 μm) or less by filtering the TiO ₂ powder using a 325 mesh or the like.

In the above region 9a of the sheet 9, TiO ₂ is about 39~59wt%, MnO ₂ is about 1.0~1.6wt%.

As shown in FIG. 4D, when the tip portion 1a of the optical fiber 1 is brought into contact with the sheet 9 containing TiO ₂ and a laser beam having an output of about 6 W is emitted to the optical fiber 1, the laser beam is emitted. The fiber tip 1a is heated and melted by the scattering and absorption by the loss body 6 and the heat generated at that time, and TiO ₂ diffuses into the tip 1a. At this time, the TiO ₂ may be diffused into the distal end portion 1a by repeatedly contacting and separating the distal end portion 1a of the optical fiber 1 and the sheet 9 in a state where the laser beam (L) is output. The temperature of the fiber tip 1a during heating is about 4000K, and the tip 1a emits light.

When the white powder such as TiO ₂ is diffused into the tip end portion 1a of the optical fiber 1, only a small amount of a black light absorber (black body) such as MnO ₂ is added to the region of the sheet 9 in order to melt the SiO _2. 9a. The content of MnO ₂ is preferably such that the black body is burned out when the SiO ₂ at the tip 1a is melted.
For example, if the content of the black body is too large, the black body diffuses and remains in the tip portion 1a of the optical fiber together with TiO _{2 and the} like, and when the laser beam is incident, the fiber tip instantaneously becomes higher than necessary, SiO ₂ is melted so that TiO ₂ cannot be maintained. When the content ratio of the black body is too small, SiO ₂ does not melt the fiber tip 1a. This black body such as MnO _{2 is used} as an igniter for bringing the tip 1a of the optical fiber 1 into a high temperature state. That is, when a laser beam is incident on the tip 1a of the optical fiber 1, first, a black body such as MnO ₂ is heated, and then SiO ₂ is melted to diffuse TiO ₂ .

As shown in FIG. 4E, when laser light is incident on the optical fiber 1 to bring the tip 1a to a high temperature state, the tip 1a of the optical fiber 1 becomes hemispherical due to melting. Further, titanium oxide (TiO ₂ ) as the optical loss body 6 is diffused in the surface layer in the fiber tip 1a. Further, when the incidence of the laser beam is stopped and the fiber tip 1a is cooled, the fiber tip 1a is solidified in a substantially hemispherical shape as shown in FIG. 4 (e).

<Electron micrograph>
FIG. 5 is a diagram showing an example of an electron micrograph of the tip 1a of the optical fiber 1 of the laser photothermal conversion device 100 according to the embodiment of the present invention. Specifically, FIG. 5 shows that laser light is intermittently incident on the distal end portion 1a of the optical fiber 1 two or three times, and the distal end portion 1a is melted at a high temperature, and then the distal end is stopped by stopping the laser light incidence. The tip 1a is observed by an electron microscope when the tip 1a is cooled and the tip 1a is solidified again.

As shown in FIG. 5, the distal end portion 1 a of the optical fiber 1 is formed in a substantially hemispherical shape by melting by laser light incidence and solidification by stopping the laser light incidence. When the optical fiber 1 including the coating 4 and having a fiber diameter of 400 μm (core diameter is about 50 μm and cladding outer diameter is about 300 μm), the tip 1a of the optical fiber 1 has TiO ₂ as the optical loss body 6 from the surface. 1 to 200 μm is diffused and embedded.
When the optical fiber 1 having a fiber diameter of 800 μm including the coating 4 is used, the tip portion 1a of the optical fiber 1 is in a state where TiO ₂ as the optical loss body 6 is diffused from the surface by about 1 to 400 μm and embedded. It becomes. That is, the diffusion distance of TiO ₂ from the surface of the fiber tip 1a tends to increase according to the fiber diameter.
The fiber tip 1a is formed in a substantially hemispherical shape by melting and re-solidification, and has a diameter portion slightly larger than the diameter of the clad 3 of the optical fiber 1.

  Since the distal end portion 1a of the optical fiber 1 according to the embodiment of the present invention is formed in a substantially hemispherical shape having a diameter portion slightly larger than the diameter of the cladding 3, as shown in FIG. At the time of light emission, light can be emitted not only in the axial direction but also in almost all directions.

<Light emission control>
FIG. 6 is a diagram illustrating an example of the operation of the heating device 200 according to the embodiment of the present invention, and FIG. 6A is a diagram illustrating an example of a current value input to the semiconductor laser element of the laser light generator 10. 6B is a diagram showing an example of the intensity of the laser beam output from the laser beam generator 10, and FIG. 6C is a diagram showing an example of the emission intensity of the fiber tip 1a.

  Next, the control unit 15 of the heating device 200 controls the high temperature and light emission state of the tip 1a of the optical fiber 1 by controlling the output level, on-time, off-time, etc. of the laser beam by the laser beam generation unit 11. An example will be described.

  As shown in FIG. 6A, the control unit 15 inputs a drive current to the semiconductor laser element in the laser light generating unit 11, and from the semiconductor laser element in the laser light generating unit 11, the control unit 15 Processing to intermittently output the laser beam as shown is performed. When the laser light from the laser light generation unit 11 enters the optical fiber 1, the tip 1a of the optical fiber 1 emits light in response to the incidence of the laser light, as shown in FIG. 6C.

More specifically, as shown in FIG. 6A, when a predetermined level of current is input to the semiconductor laser element at the reference time of 0 s (seconds), as shown in FIG. After 2 ms, the laser light intensity reaches a predetermined level. As shown in FIG. 6C, after about 15 ms from the reference time, the light emission intensity at the tip of the optical fiber 1 starts to increase from zero.
When the laser beam is turned on for about 100 ms, the light emission intensity of the optical fiber tip 1a increases with time, and the fiber tip reaches a high temperature of about 4000K.

  When the current is decreased from a predetermined level to 0, the light emission intensity of the laser light becomes 0, the light emission intensity of the fiber tip 1a suddenly decreases with time, and about 30 from the time when the magnitude of the current becomes 0. After ˜50 ms, the emission intensity of the fiber tip 1a becomes 0, and the fiber tip 1a cools. Then, after a predetermined time has elapsed, the current is repeatedly turned on / off again.

  The controller 15 controls the high temperature, light emission, and cooling of the fiber tip 1a by adjusting the on time and off time of the laser light.

  If the on time of the laser beam is shorter than the predetermined time, the fiber tip 1a does not emit light because the temperature is not sufficiently high. For this reason, the control unit 15 controls the on-time of the laser beam so that it is sufficient for the tip 1a of the optical fiber 1 to reach a high temperature and emit light.

If the on time of the laser beam is longer than the predetermined time, the fiber tip 1a becomes unnecessarily hot, and the speed at which the fiber tip 1a is shortened by melting increases.
For this reason, the control unit 15 performs control to set the on-time of the laser light so that the speed at which the tip of the optical fiber 1 is shortened by melting is small (less than a predetermined speed).
In the present embodiment, the on-time of the laser beam is about 30 to 600 ms, and preferably about 50 to 200 ms.

  If the intensity of the laser beam is lower than a predetermined level, the fiber tip 1a does not emit light because the temperature is not sufficiently high. For this reason, the control part 15 performs control which sets so that it may become intensity | strength sufficient for the front-end | tip part of the optical fiber 1 to become high temperature and to light-emit.

On the other hand, if the intensity of the laser beam is higher than the specified level, the fiber tip 1a becomes unnecessarily hot, and the speed at which the fiber tip 1a is shortened by melting increases. The body 6 is burnt down.
For this reason, the control unit 15 reduces the intensity of the laser light so that the optical loss 1 at the tip of the fiber is not burned out and the speed at which the tip of the optical fiber 1 is shortened by melting is smaller (less than a predetermined speed). Control to set the laser intensity.
In this embodiment, when the optical fiber 1 having a fiber diameter of 400 μm including the coating 4 is used, the intensity of the laser light is about 2 to 20 W, preferably about 4 to 8 W.
Further, the intensity of the laser light and the like are appropriately set according to the diameter of the optical fiber 1. For example, the intensity of the laser beam is set to be larger as the diameter of the optical fiber 1 is larger.

Further, as described above, after about 30 to 50 ms from the time when the current decreases from the predetermined level to 0, the light emission intensity of the fiber tip 1a becomes 0, and the fiber tip 1a is cooled.
For this reason, the control part 15 controls the heating and cooling of the front-end | tip part 1a of the optical fiber 1 by adjusting the on-time and off-time of a drive current, and reduces degradation of the front-end | tip part 1a of the optical fiber 1. Can do.
In the example shown in FIG. 6, the period T ₀ is 0.3 s, the on-time Ta is 0.12 s, and the duty ratio is 0.4.

  FIG. 7 is a diagram illustrating another example of the operation of the heating device 200 according to the embodiment of the present invention. FIG. 7A illustrates an example of a current value input to the semiconductor laser element of the laser light generator 10. FIG. 7B is a diagram showing an example of the emission intensity of the fiber tip 1a.

As shown in FIGS. 7A and 7B, the drive current and laser are output with two on-times as one group. In the example shown in FIG. 7 relates two laser oscillation in a group, the first and second laser emission time (Ta _1, Ta ₂₎ is about 0.09 S, the first and second laser exit The off time Tb ₁ during the time is 0.01 s. The period T _{0 of} each group is about 0.3 s. In the present embodiment, a group off time Tb ₂ is provided as a cooling time between the groups.

Specifically, as shown in FIG. 7, after the fiber tip 1a is heated by turning on the first laser (0 to 0.09 s) and the laser tip 1a is cooled to a laser level 0 for a predetermined time ( 0.09 to 0.10 s), the fiber tip 1a is heated by turning on the second laser (0.10 to 0.19 s), and the fiber tip 1a is cooled by setting the laser level to 0 for a predetermined time. .19s ~).
As described above, the control unit 15 performs control so that an off time (cooling time) of only about 0.01 s is provided between the first laser and the second laser in one group. The temperature of the tip end portion 1a can be set to a high temperature state and a light emission state substantially continuously for a relatively long time.

  FIG. 8 is a diagram illustrating an example of the operation of the laser photothermal conversion device 100 according to the embodiment of the present invention, and FIG. 8A is an example of the current value input to the semiconductor laser element of the laser photothermal conversion device 100. FIG. 8B is a diagram showing an example of the light emission intensity of the fiber tip 1a when the fiber tip 1a is placed in the air. FIG. 8C is a diagram showing the fiber tip 1a in the hyaluronic acid solution. The figure which shows an example of the emitted light intensity at the time of arrange | positioning, FIG.8 (d) shows the figure which shows an example of the emitted light intensity at the time of arrange | positioning the fiber front-end | tip part 1a in physiological saline.

  In the laser photothermal conversion device 100, the output of the laser beam is set to 5 W, and the wavelength of the laser beam is set to 980 nm.

  The inventor of the present application measured the light emission intensity of the fiber tip 1a when the fiber tip 1a of the laser photothermal conversion device 100 was placed in air, hyaluronic acid solution, or physiological saline. The physiological saline is a saline containing 0.9 w / v% sodium chloride. Hyaluronic acid is contained in joints, vitreous bodies and the like in living tissues, and particularly in articular cartilage.

  When the laser beam is incident on the optical fiber 1, as shown in FIGS. 8 (b), 8 (c), and 8 (d), the tip of the fiber can be used even in air, hyaluronic acid solution, or physiological saline. It was confirmed that the part 1a became hot and emitted light. Further, the inventor of the present application has confirmed the high temperature state and the light emission state of the fiber tip 1a even when the fiber tip 1a is disposed in pure water.

  FIG. 9 is a diagram illustrating an example of the intensity of the laser light transmitted from the fiber tip 1a in a high temperature state during the operation of the laser photothermal conversion device 100 according to the embodiment of the present invention.

This inventor measured the intensity | strength of the laser beam permeate | transmitted from the fiber front-end | tip part 1a of the high temperature state of the laser photothermal conversion apparatus 100. FIG. The horizontal axis represents the incident laser intensity (W), and the vertical axis represents the intensity of the transmitted laser beam. Measurement was performed using an optical fiber 1 having a fiber diameter of 400 μm.
In the above measurement, the light intensity was measured through a filter that transmits a laser beam having a wavelength of 850 nm or longer and shields light having a wavelength shorter than that. At the time of measurement, as shown in FIG. 8A, the drive current was input to the semiconductor laser element, and the laser was incident on the optical fiber 1.

As shown in FIG. 9, when the intensity of the incident laser is 4 to 8 W, it is a substantially constant value. In this range, the energy of the detected laser light is 0.1 to 0.1 relative to the energy of the incident laser. It is about 0.2%. That is, it is estimated that about 99.98% of the energy of the incident laser light is converted into thermal energy at the fiber tip 1a.
Thus, in this embodiment, when the output of the incident laser light is 4 to 8 W, the energy of the incident laser light can be converted into thermal energy with high efficiency.

As the intensity of the incident laser is greater than 8 W, the intensity of the laser beam transmitted from the fiber tip 1a in the high temperature state increases, and the conversion efficiency to heat energy decreases.
Further, as the intensity of the incident laser is smaller than 4 W, the intensity of the laser beam transmitted from the fiber tip 1a in the high temperature state is reduced, and the temperature of the fiber tip 1a is lowered.

  For example, when a thick optical fiber 1 having a diameter of about 800 μm is used, the laser output is preferably about 8 W to 20 W. Further, when the optical fiber 1 having a diameter of about 200 μm is used, it is preferable that the laser output is about 2 to 3 W (eg, root-to-root treatment).

As described above, the laser photothermal conversion device 100 has a characteristic that the intensity of the laser light transmitted from the fiber tip 1a in a high temperature state changes depending on the intensity of the laser light incident on the fiber tip 1a. For this reason, the control unit 15 makes the incident laser light so that the change value of the intensity of the laser beam transmitted from the fiber tip 1a in the high temperature state becomes zero or a value smaller than the predetermined value with respect to the change of the intensity of the incident laser beam. Sets the light intensity.
By doing in this way, the laser photothermal conversion apparatus 100 can convert a laser beam into a thermal energy with high efficiency in the fiber front-end | tip part 1a in a high temperature state.

  On the other hand, if the on-time of the laser beam is shorter than the predetermined time, the fiber tip 1a does not emit light because the temperature is not sufficiently high.

As described above, in the laser photothermal conversion device 100 using the optical fiber 1 according to the embodiment of the present invention, the tip portion 1a of the optical fiber 1 is in a state where the powder of the light loss body 6 is diffused by melting and solidifying. Thus, SiO ₂ as the light transmitting body of the tip 1a is in a point defect state. When the laser beam is incident on the optical fiber 1 from the laser beam generator 11, the light loss body 6 at the tip 1a is diffused (embedded) in the region (surface layer) due to light loss such as scattering and absorption of the laser beam. The tip portion 1a becomes high temperature, the SiO ₂ of the fiber tip portion 1a becomes high temperature, the high-temperature state SiO ₂ absorbs the laser beam and becomes higher temperature, and the tip portion 1a emits light in a molten state. The temperature of the tip 1a is about 4000K. The light spectrum generated by the light emission of the tip 1a has a broad intensity over the visible light region.
That is, even when low-power laser light is incident, the laser light-to-heat converter 100 (optical fiber) can convert the laser light into heat energy with high efficiency at the tip 1a of the optical fiber 1 with a simple structure. 1) can be provided.

  Further, as described above, it is possible to provide the laser photothermal conversion device 100 (optical fiber 1) provided with the fiber tip 1a that becomes a high temperature of about 4000 K when the laser is incident.

Further, the heating device 200 according to the embodiment of the present invention includes a laser photothermal conversion device 100 (optical fiber 1), a laser light generation unit 11 that makes laser light incident on the optical fiber 1, and an output of laser light from the laser light generation unit 11. And a control unit 15 for controlling. The control unit 15 performs a process of controlling the laser light generation unit 11 so that the tip 1a of the optical fiber 1 is brought into a high-temperature and molten state, and a laser beam that emits light from the tip 1a is emitted.
For this reason, even if it is a low output laser beam, the heating apparatus 200 provided with the laser photothermal conversion apparatus 100 which can convert a laser beam into thermal energy with high efficiency by the front-end | tip part 1a of the optical fiber 1 with simple structure. Can be provided.

  In the embodiment of the present invention, since the optical fiber 1 is formed in a substantially hemispherical shape by melting as described above, the optical fiber 1 transmits thermal energy with high efficiency to the surroundings when the optical fiber 1 emits light. be able to. Further, as described above, a part of the tip 1a is formed in a substantially hemispherical shape having a diameter larger than the cladding diameter, so that light can be emitted in almost all directions.

  Moreover, since the heating apparatus 200 having the laser photothermal conversion apparatus 100 according to the embodiment of the present invention includes the fiber tip 1a that emits light at a high temperature, transpiration, incision, and the like of a living tissue can be easily performed in a short time. A heating device 200 that can be provided can be provided.

  Further, the laser photothermal conversion device 100 according to the embodiment of the present invention emits light with a broad emission spectrum at least in the visible light region at a high temperature and in a molten state at the tip 1a of the optical fiber 1, so that the configuration is simple. For example, it is possible to provide the laser photothermal conversion device 100 that can convert a single wavelength laser beam into light having a broad emission spectrum over the visible light region and emit the light.

  In the embodiment of the present invention, white light having a broad emission spectrum in the visible light region is emitted from the distal end portion 1a of the optical fiber 1 of the laser photothermal conversion device 100. Therefore, for example, a treatment for melting the fat of biological tissue is performed. When performing, laser light heat capable of performing treatment with substantially no bleeding by absorbing light with a wavelength of about 500 nm to 600 nm with high efficiency among white light emitted from the distal end portion 1a and coagulating the blood vessel itself. A heating device 200 having the conversion device 100 can be provided.

In the embodiment of the present invention, the material for forming the core 2 of the optical fiber 1 includes quartz (SiO ₂ ), and the optical loss body 6 includes titanium oxide (TiO ₂ ). It is possible to provide the laser photothermal conversion device 100 that exhibits the effect.

  In the embodiment of the present invention, the tip 1a of the optical fiber 1 of the laser photothermal conversion device 100 emits light at a high temperature and can raise the temperature of surrounding materials in a short time. It is possible to provide the heating device 200 having the laser photothermal conversion device 100 capable of performing transpiration and incision on a wide range of living tissues.

  Moreover, according to the heating apparatus 200 having the laser photothermal conversion apparatus 100 according to the embodiment of the present invention, a hole having a diameter of about the fiber diameter can be formed in the dentin portion of the tooth by the high temperature light emitting portion of the fiber tip 1a. . Further, in the treatment of gums, the living tissue can be transpired with high efficiency by the high temperature light emitting portion of the fiber tip 1a of the laser photothermal conversion device 100. That is, the heating device 200 having the laser photothermal conversion device 100 can be used for dental treatment or the like.

  In addition, according to the heating device 200 including the laser photothermal conversion device 100 according to the embodiment of the present invention, the control unit 15 moves from the front end portion 1a of the optical fiber 1 to the front end portion 1a of the optical fiber 1 for laser light from when the front end portion 1a does not emit light. As a result of the incident, the tip 1a becomes a temperature higher than the specified temperature, and the forming material of the tip 1a that has become the light absorber absorbs the laser beam, and only the time required for the tip 1a to emit light at a high temperature and in a melted state. Since at least the process of intermittently emitting the laser beam by the laser beam generation unit 11 is performed, the heating device 200 capable of easily controlling the light emission of the distal end portion 1a by the control unit 15 can be provided.

  In addition, according to the heating device 200 including the laser photothermal conversion device 100 according to the embodiment of the present invention, the control unit 15 intermittently emits laser light and repeats heating and cooling of the tip 1a of the optical fiber 1. Since the process is performed, it is possible to provide the heating device 200 that can reduce the deterioration of the tip end portion 1a of the optical fiber 1 and emit light from the tip end portion 1a.

Further, in the method of manufacturing the laser photothermal conversion device 100 using the fiber according to the embodiment of the present invention, the core 4 and the cladding 3 are exposed by removing the coating 4 at the tip of the optical fiber 1 as shown in FIG. Laser light is emitted from the distal end portion 1a of the optical fiber 1 in a state where the distal end portion 1a of the optical fiber 1 is brought into contact with a sheet 9 that is a contacted body containing powder of a light loss body 6 such as TiO ₂ or MnO _2. The step of bringing the forming material of the tip 1a of the optical fiber 1 into a high-temperature and molten state, and stopping the emission of the laser light to solidify the tip 1a of the optical fiber 1, causing the optical loss to the tip 1a of the optical fiber. Forming a surface layer in which the material is diffused.
For this reason, the manufacturing method of the laser photothermal conversion apparatus 100 which can manufacture the said laser photothermal conversion apparatus 100 easily can be provided.

In the present embodiment, the sheet 9 as the contacted body contains titanium oxide (TiO ₂ ) and manganese oxide (MnO ₂ ) powder that functions as an ignition agent. For this reason, the manufacturing method of the laser photothermal conversion apparatus 100 which can manufacture the laser photothermal conversion apparatus 100 easily can be provided.

In the above embodiment, the tip 1a of the optical fiber 1 is processed using a sheet containing powder such as TiO ₂ as a light loss material. However, the present invention is not limited to this form.
For example, zirconia powder or the like may be used as the light loss body 6. Further, the optical loss body 6 may be zinc oxide, cerium oxide or the like in addition to TiO ₂ . Further, MnO ₂ for melting SiO ₂ may be a black body such as carbon or iron oxide.

  As the optical fiber 1 of the laser photothermal conversion device 100 according to the embodiment of the present invention, a multimode or single mode fiber may be employed.

  In the above-described embodiment, the laser light generation unit 11 outputs the laser light in the repeat mode and the CW mode. However, the present invention is not limited to this mode. For example, the laser beam generator 11 may output a pulse laser.

Moreover, in the said embodiment, although the optical fiber 1 whose fiber diameter including the coating | coated 4 is 400 micrometers was used, it is not restricted to this form. It is preferable to use an optical fiber 1 having an optimum diameter as appropriate according to the use situation, such as a diameter of 200 μm to 800 μm. For example, a thin fiber having a fiber diameter of about 200 μm is useful for dental treatment and the like, and root treatment (sterilization treatment for removing carious nerve) can be performed efficiently. As a comparative example, it is necessary to repeat the hospital visit 4 to 5 times if it is a general root treatment by chemical treatment, but if the heating device 200 according to the present invention is used, the root treatment is performed by a single treatment. Is possible.
Further, for example, a heating device 200 employing a thick one having a diameter of about 800 μm as the optical fiber 1 can be used to perform operations such as subcutaneous fat dissolution in a short treatment time.

As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments, and there are design changes and the like without departing from the gist of the present invention. Is included in the present invention.
Further, the embodiments described in the above drawings can be combined with each other as long as there is no particular contradiction or problem in the purpose and configuration.
Moreover, the description content of each figure can become independent embodiment, respectively, and embodiment of this invention is not limited to one embodiment which combined each figure.

1 Optical fiber (fiber, laser photothermal converter)
1a tip 2 core (light transmitting body)
DESCRIPTION OF SYMBOLS 3 Cladding 4 Coating | covering 6 Optical loss 9 Sheet | seat 9a Area | region containing the powder of optical loss body 10 Laser photothermal conversion apparatus 11 Laser light generation part 12 Operation input part 13 Display part 14 Storage part 15 Control part (CPU)
100 Laser photothermal conversion device 200 Heating device

Claims (9)

A laser photothermal conversion device using a fiber,
It has a fiber comprising a core including a forming material that is a light transmitting body at a specified temperature or lower and becomes a light absorber having a higher absorbance of laser light as the temperature is higher than the specified temperature, and a clad,
The fiber has a surface layer in which the powder of the optical loss material is diffused at the tip thereof,
When the laser light is incident on the tip portion through the core, the fiber is a light loss due to the light loss material on the surface layer, and the tip portion becomes a temperature higher than the specified temperature, and becomes the light absorber. In addition, a laser light-to-heat converter using a fiber, wherein the forming material of the tip portion absorbs the laser light, so that the tip portion emits light at a high temperature and in a molten state.   2. The laser light-to-heat conversion device using a fiber according to claim 1, wherein the fiber emits light with a broad emission spectrum over at least the visible light region when the tip is at a high temperature and in a molten state.   The laser light-to-heat converter using a fiber according to claim 1 or 2, wherein the tip of the fiber is formed in a substantially hemispherical shape. The forming material of the fiber core includes quartz (SiO ₂ ),
The laser light heat conversion apparatus using a fiber according to any one of claims 1 to 3, wherein the optical loss material includes titanium oxide (TiO ₂ ). A heating device having a laser photothermal conversion device using the fiber according to any one of claims 1 to 4,
A laser beam generator that emits laser beam to the fiber;
A control unit for controlling the emission of the laser beam by the laser beam generation unit so that the tip of the fiber emits light at a high temperature and in a molten state;
A heating device comprising:   The control unit is configured such that, when the tip of the optical fiber is not emitting light, the tip becomes a temperature higher than the specified temperature due to incidence of the laser light on the tip of the fiber, and becomes the light absorber. The forming material at the tip absorbs the laser beam and performs a process of intermittently emitting the laser beam at least by the laser beam generator for a time required for the tip to emit light at a high temperature and in a molten state. The heating apparatus according to claim 5.   The heating apparatus according to claim 6, wherein the control unit emits the laser light intermittently and performs a process of repeatedly heating and cooling the tip of the fiber. A method for manufacturing a laser light-to-heat conversion device, which manufactures a laser light-to-heat conversion device using the fiber according to claim 1,
A light loss body powder comprising a core including a forming material that is a light transmitting body at a specified temperature or lower, and a light absorber that has a higher absorbance of laser light as the temperature is higher than the specified temperature, and a clad. A step of emitting a laser beam from the tip of the fiber in a state of being in contact with a contacted body containing a body, and bringing the forming material of the tip of the fiber into a high-temperature and molten state;
Stopping the emission of the laser beam, solidifying the tip of the fiber, and forming a surface layer in which the optical loss material is diffused in the fiber tip; and
A method for producing a laser photothermal conversion device, comprising: The method for manufacturing a laser photothermal conversion device according to claim 8, wherein the contacted body contains powder of titanium oxide (TiO ₂ ) and manganese oxide (MnO ₂ ).