Laser device and laser treatment device

Abstract

The present disclosure provides a laser device and a laser treatment device having a resonator that does not reduce performance and has little risk of malfunction associated with a mirror. A laser device (30) according to the present disclosure is provided with: a resonator including a columnar solid laser rod (31), a first reflective film provided on a first end surface of the solid laser rod (31), and a second reflective film provided on a second end surface of the solid laser rod (31) on the opposite side from the first end surface; and a flash lamp (32) that excites the solid laser rod (31). The first reflective film and the second reflective film are ion beam sputtering coating films capable of preventing intrusion of moisture from outside air. The reflectivity of the first reflective film is lower than the reflectivity of the second reflective film.

Description

TECHNICAL FIELD

[0001] The present application relates to a laser device and a laser treatment device. BACKGROUND

[0002] In recent years, in the dental field, a laser is used for treatment such as caries removal, tartar removal, gum incision. For example, the treatment uses a laser treatment device that can emit an Er:YAG (Erbium / Yttrium Aluminum Garnet) laser of a wavelength of 2.94 μm. In the laser treatment device that emits the Er:YAG laser, a laser device having a resonator including a solid laser rod is built in.

[0003] In the case of such a resonator including a solid laser rod, a total reflection mirror and an output mirror are disposed at both ends of the solid laser rod. However, since the absorption of infrared light of a wavelength of 2 μm or more with respect to an O-H group contained in water and the like becomes large, if moisture in the air is adsorbed to the total reflection mirror and the output mirror of the resonator, the adsorbed moisture sometimes absorbs infrared light and generates heat, causing damage to the total reflection mirror and the output mirror, and reducing the performance of the resonator.

[0004] In the laser device disclosed in Japanese Patent Application Publication No. 08-316552, in order to prevent moisture from being adsorbed to the total reflection mirror and the output mirror of the resonator, a beam tube is provided at both ends of the solid laser rod. The beam tube is a structure in which the total reflection mirror and the output mirror of the resonator are not exposed to the air, and a liquid having a property of transmitting infrared light such as fluorine-based oil is filled in the beam tube. SUMMARY

[0005] However, the beam tube provided at both ends of the solid laser rod needs to adopt a structure of sealing the liquid, and it is not easy to manage the sealed liquid, and the cost of manufacturing and maintaining becomes high. In addition, in the laser device disclosed in Patent Document 1, there is a risk of failure in which the structure of sealing the liquid is broken and the sealed liquid leaks.

[0006] The present disclosure is made to solve the above-described problems, and aims to provide a laser device and a laser treatment device having a resonator in which the performance is not reduced and the risk of failure related to the mirror is low.

[0007] The laser device according to the present disclosure is a laser device in which the absorption coefficient of water is 20 cm -1A laser device for emitting laser light of a wavelength above 100 nm comprises: a resonator comprising a cylindrical solid-state laser rod; a first reflective film provided on a first end face of the solid-state laser rod; and a second reflective film provided on a second end face of the solid-state laser rod opposite the first end face; and a flash lamp for exciting the solid-state laser rod. The first and second reflective films are ion beam sputtering coatings that prevent the intrusion of moisture from the outside air. The reflectivity of the first reflective film is lower than that of the second reflective film.

[0008] The laser treatment device according to the present disclosure is a laser treatment device that treats an affected area using laser light, and includes the aforementioned laser device that emits laser light.

[0009] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a diagram showing the appearance of a laser treatment device according to an embodiment.

[0011] Figure 2 It is a diagram showing the appearance of a laser treatment device according to an embodiment.

[0012] Figure 3 It is a diagram for explaining the structure of a laser device according to an embodiment.

[0013] Figure 4 This is a diagram showing the appearance of a solid-state laser bar according to an embodiment. DETAILED DESCRIPTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the same or corresponding parts in the drawings are denoted by the same reference numerals, and their description will not be repeated.

[0015] [Composition of laser treatment device]

[0016] While referring to Figure 1 and Figure 2 , while describing the main components of a laser treatment device 1 according to an embodiment. The laser treatment device 1 according to an embodiment is used, for example, in dental practice to treat teeth within a patient's oral cavity. It should be noted that the laser treatment device 1 according to an embodiment can also be used in fields other than dentistry, such as plastic surgery, otolaryngology, surgery, urology, dermatology, and ophthalmology.

[0017] Figure 1 and Figure 2 1 is a diagram showing the appearance of the laser treatment device 1 according to the embodiment. Figure 1 and Figure 2As shown, the laser treatment device 1 is provided with a housing 10. The housing 10 is formed in a rectangular parallelepiped or substantially rectangular parallelepiped including an upper surface 10A, a bottom surface 10B, a front surface 10C, a back surface 10D, a right side surface 10E, and a left side surface 10F, and houses various components provided in the laser treatment device 1. Hereinafter, in a case where the laser treatment device 1 is disposed on a disposition surface, an axis in a lateral direction (a short edge direction of the front surface 10C and the back surface 10D) of the housing 10 is defined as an X axis, an axis in a longitudinal direction (a short edge direction of the right side surface 10E and the left side surface 10F) of the housing 10 is defined as a Y axis, and an axis in a height direction (a long edge direction of the front surface 10C, the back surface 10D, the right side surface 10E, and the left side surface 10F) of the housing 10 is defined as a Z axis, and the laser treatment device 1 is described.

[0018] The laser treatment device 1 is provided with a connection portion 11, a waveguide 12, a handpiece 13, a holding portion 14, a connection portion 15, at least one leg portion 17, a handle 18, a display 19, and a tray 20.

[0019] The connection portion 11 is provided on the upper surface 10A of the housing 10 and has a rod along which the waveguide 12 is to be passed. The connection portion 11 is configured to be changed in accordance with an operation of the waveguide 12, and by passing the waveguide 12 having a flexible shape along the rod, a user is able to move the waveguide 12 to a desired position. The waveguide 12 is flexibly elongated and transmits laser light transmitted from a laser device (see FIG. 2) provided in the inside of the housing 10 to the handpiece 13. The handpiece 13 emits the laser light transmitted via the waveguide 12 to the outside. Figure 3

[0020] The holding portion 14 is provided on the upper surface 10A of the housing 10 and is rotatable in an X-Y plane on the upper surface 10A. The holding portion 14 fixes the handpiece 13 to the housing 10 by holding the handpiece 13 with a front end thereof.

[0021] The connection portion 15 is provided on the upper surface 10A of the housing 10 and connects the waveguide 12 to the upper surface 10A. The connection portion 15 connects a laser device provided in the inside of the housing 10 to the waveguide 12 and connects a water path (not shown) provided along the waveguide 12 to a tube pump (not shown) provided in the inside of the housing 10. The water path supplies cleaning water supplied from the tube pump provided in the inside of the housing 10 to the handpiece 13. The handpiece 13 emits the cleaning water supplied via the water path to the outside.

[0022] The at least one leg portion 17 is provided on the bottom surface 10B of the housing 10 and creates a gap between the bottom surface 10B and a disposition surface on which the housing 10 is disposed. Specifically, the at least one leg portion 17 includes at least one wheel 170, respectively. The housing 10 is brought into contact with the disposition surface via the at least one wheel 170 provided on the bottom surface 10B, and a gap is created between the bottom surface 10B and the disposition surface by the at least one wheel 170. ​

[0023] In the laser treatment device 1 according to the embodiment, four feet 17A, 17B, 17C, 17D are provided on the bottom surface 10B of the housing 10. The four feet 17A, 17B, 17C, 17D each include four wheels 170A, 170B, 170C, 170D. Hereinafter, the four feet 17A, 17B, 17C, 17D will also be collectively referred to as "feet 17". The four wheels 170A, 170B, 170C, 170D will also be collectively referred to as "wheels 170". By rotating the wheels 170 on a setting surface of the laser treatment device 1, the laser treatment device 1 is able to move on the setting surface. Thereby, for example, a user is able to move the laser treatment device 1 to a place where a patient is located in a case where the laser treatment device 1 is used, and on the other hand, is able to move the laser treatment device 1 to a storage place in a case where the laser treatment device 1 is not used. Note that at least one of the feet 17 can not include at least one of the wheels 170, and can simply fix the housing 10 to the setting surface.

[0024] The handle 18 is a portion that is held by a user when moving the laser treatment device 1. The display 19 displays various information related to treatment of a patient using the laser treatment device 1. The tray 20 loads treatment instruments and the like that are required when a user treats a patient using the laser treatment device 1.

[0025] In addition, although the mounting position is not illustrated in Figure 1 and Figure 2 , the laser treatment device 1 is provided with a laser device (refer to Figure 3 ). The laser device includes a resonator (oscillator) for generating laser light. As will be described later, the resonator includes a solid laser rod and a flash lamp (light source). The solid laser rod is, for example, a YAG crystal to which Er is added as an active element. The solid laser rod becomes an excited state by irradiation of excitation light from the flash lamp, and radiates laser light by amplifying spontaneous emission light with the resonator.

[0026] Note that the solid laser rod included in the oscillator is not limited to an Er:YAG rod, which is a YAG crystal to which Er is added as an active element, and can be, for example, a YAG crystal to which either of Er and Ho is added as an active element. In addition, the solid laser rod is not limited to a YAG crystal, and can be any solid laser medium doped with a lanthanoid rare earth element. The solid laser rod can be, for example, an Er;Cr:YSGG crystal, a Ho:YAG crystal, or the like.

[0027] According to the laser treatment device 1 configured as described above, the user can configure the front end of the handpiece 13 near the affected part of the patient by elongating the waveguide 12 while holding the handpiece 13, and make the laser and the cleaning water emitted from the front end of the handpiece 13 touch the affected part. Thus, the user can treat the affected part using the laser emitted by the laser treatment device 1.

[0028] [Configuration of laser device]

[0029] Figure 3 is a view for explaining the configuration of a laser device 30 according to the embodiment. The laser device 30 includes a resonator having a columnar solid laser rod 31, and a flash lamp 32 that excites the solid laser rod 31. Further, the laser device 30 includes a support member 33 that holds the solid laser rod 31 and is fixed to the housing 10 of the laser treatment device 1, a detection device 34 that detects laser, and a control substrate 35 that controls the output of the flash lamp 32 based on the detected laser.

[0030] In the laser treatment device 1 used in the medical field such as dental treatment, the laser irradiated to the affected part is absorbed by water and hydroxyapatite, which are main components of the biological tissue of the affected part, and treatment such as incision, hemostasis, coagulation, and evaporation can be performed. In the treatment, it is necessary to use laser having high absorption rate to the affected part locally, and to minimize the influence of the transmitted light on the surrounding healthy tissue. For this reason, laser of a wavelength having high water absorption (absorption coefficient 20 cm -1 or more) is preferable, which is different from the wavelength generally used in industrial use.

[0031] For example, in the case where the laser device 30 uses Ho:YAG crystal for the solid laser rod 31, the absorption coefficient of water of the laser emitted by the laser device 30 is 32 cm -1 . In addition, in the case where the laser device 30 uses Er:YAG crystal and Er;Cr:YSGG crystal for the solid laser rod 31, the absorption coefficient of water of the laser emitted by the laser device 30 is 12000 cm -1 and 5000 cm -1 , respectively. (Document D. J. Segelstein, “The complex refractive index of water,” University of Missouri-Kansas City (1981).)

[0032] In addition, in the laser treatment device 1 used in the medical field such as dental treatment, in order to reduce the thermal influence on the surrounding healthy tissue at the time of incision and evaporation, it is preferable that the laser emitted by the laser device 30 be pulse laser. Specifically, it is preferable that the laser emitted by the laser device 30 be pulse laser having a pulse width of 10 μs to 1000 μs.

[0033] The solid laser rod 31 becomes an excited state by irradiation of excitation light from the flash lamp 32, and a resonator is required in order to amplify the light of spontaneous emission. In a general laser device, the resonator is configured by disposing an output mirror (partial reflector) at a position apart by a prescribed distance from one end of the solid laser rod, and disposing a total reflector at a position apart by a prescribed distance from the other end of the solid laser rod.

[0034] However, the absorption coefficient of water is 20 cm -1 Infrared light of the above wavelength is greatly absorbed by the O-H group contained in water and the like, and if moisture in the air is adsorbed to the total reflector and the output mirror of the resonator, the adsorbed moisture sometimes absorbs infrared light and generates heat, causing damage to the total reflector and the output mirror.

[0035] Therefore, in the laser device 30 according to the present embodiment, instead of configuring the total reflector and the output mirror separately from the solid laser rod 31, a configuration is adopted in which a reflective film is formed directly on the end face of the solid laser rod 31, and the reflective film is formed of an ion beam sputtering coating film capable of preventing the intrusion of moisture from the outside air. Figure 4 is a view showing the external appearance of the solid laser rod 31 according to the present embodiment.

[0036] As shown in Figure 4 The solid laser rod 31 is configured to be capable of constituting the resonator 40 and generating laser oscillation by providing the first reflective film 31a on the end face (first end face) at one end, and providing the second reflective film 31b on the end face (second end face) at the other end. That is, the first reflective film 31a and the second reflective film 31b are directly coated on the end faces of the solid laser rod 31 in a structure in which the reflective surfaces of the mirrors constituting the resonator 40 are not in contact with the outside air. For this reason, the laser device 30 is capable of realizing the resonator 40 without performance degradation and without the risk of failure related to the mirrors, without providing the total reflector and the output mirror.

[0037] The first reflective film 31a and the second reflective film 31b are ion beam sputtering coating films. The ion beam sputtering coating film is a film with high density, and is capable of preventing the permeation of moisture to the reflective surfaces of the first reflective film 31a and the second reflective film 31b. The first reflective film 31a and the second reflective film 31b are reflective films formed of a film with high density, and are not limited to ion beam sputtering coating films, and can be formed by other methods.

[0038] Specifically, the first reflective film 31a and the second reflective film 31b are composed of AI2O3, Ta2O5, or SiO2. Further, it is preferable that the first reflective film 31a and the second reflective film 31b are multilayer films, at least one of the films of which includes a film composed of Ta2O5. Of course, the first reflective film 31a and the second reflective film 31b are not limited to AI2O3, Ta2O5, or SiO2, as long as they are reflective films capable of ensuring necessary reflectivity.

[0039] The first reflective film 31a corresponds to an output mirror, and is capable of reflecting light emitted from a laser crystal that becomes an excited state due to excitation light from the flash lamp 32, and emitting the amplified light as laser light. On the other hand, the second reflective film 31b corresponds to a total reflection mirror, and reflects light emitted from a laser crystal that becomes an excited state due to excitation light from the flash lamp 32. For this reason, the reflectivity of the first reflective film 31a is lower than the reflectivity of the second reflective film 31b.

[0040] For example, the reflectivity of the first reflective film 31a is about 92%, and the reflectivity of the second reflective film 31b is about 99.4%. The reflectivity of the second reflective film 31b can also be set to 100% to function as a total reflection mirror, but in the laser device 30 according to the present embodiment, the laser light that passes through the second reflective film 31b is used to monitor and control the laser light emitted from the end face on which the first reflective film 31a is provided.

[0041] Specifically, the laser device 30 detects the laser light that passes through the second reflective film 31b by means of a detection device 34. The detection device 34 includes a detector 34a that detects the laser light that passes through the second reflective film 31b, and an optical filter 34b that blocks visible light between the detector 34a and the end face on which the second reflective film 31b is provided. The detector 34a is, for example, a pyroelectric element composed of lithium tantalate (LiTaO3) or lead zirconate titanate (PZT). Note that the detector 34a is not limited to the above composition, as long as it is capable of detecting infrared light having a wavelength of 2 μm or more.

[0042] The optical filter 34b is a visible light cut filter, and is composed of, for example, silicon (Si) or germanium (Ge). By providing the optical filter 34b, stray light other than the laser light that passes through the second reflective film 31b (particularly, excitation light from the flash lamp 32) can be eliminated, and the detector 34a can accurately detect the laser light that passes through the second reflective film 31b. Of course, if it is not necessary to take measures against stray light for the detector 34a, the optical filter 34b can also be omitted.

[0043] The control substrate 35 monitors the intensity of the laser light emitted from the end face provided with the first reflecting film 31a on the basis of the intensity of the laser light detected by the detector 34a. Further, the control substrate 35 can also control the output of the flash lamp 32 on the basis of the intensity of the laser light detected by the detector 34a to control the intensity of the laser light emitted from the end face provided with the first reflecting film 31a to a set value.

[0044] Although not illustrated, the control substrate 35 has a processor and a memory. The processor controls the intensity of the laser light emitted from the end face provided with the first reflecting film 31a on the basis of the set value received by the input portion by executing various programs stored in the memory.

[0045] The processor is constituted by a CPU, a GPU, or the like, and can read and execute programs (as an example, an OS and a control program, or the like) stored in the memory. In the processor, various programs read from the memory are executed. The memory is constituted by, for example, a ROM, a nonvolatile storage device such as a flash memory, or the like. In the memory, in addition to an OS for realizing a basic function, a control program is stored.

[0046] The input portion is not limited to a specific device, and for example, a touch panel overlaid with respect to the display 19 can be cited. A part or all of the functions provided by the execution of the program by the processor can also be realized using a dedicated hardware circuit (for example, an ASIC or an FPGA, or the like).

[0047] As a method of monitoring the laser light emitted from the end face provided with the first reflecting film 31a, there is a method of splitting a part of the laser light emitted from the end face provided with the first reflecting film 31a and detecting the laser light after the splitting. In this method, it is necessary to provide a light splitting optical system, and the device will be upsized. In addition, since the light splitting optical system splits the laser light emitted from the end face provided with the first reflecting film 31a, an optical element having high resistance to the intensity of the laser light is required.

[0048] For this reason, the laser device 30 according to the present embodiment realizes the downsizing of the device by making the reflectance of the second reflecting film 31b functioning as a total reflection mirror slightly lower than 100% to make the laser light pass through, and having a function of being detected by the detection device 34. Of course, the laser device 30 can also be constituted by providing a light splitting optical system that splits a part of the laser light emitted from the end face provided with the first reflecting film 31a.

[0049] In addition, the laser device 30 according to the present embodiment can achieve downsizing and cost reduction of components by providing the first reflective film 31a and the second reflective film 31b on the end surface of the solid laser rod 31, without providing a total reflection mirror and an output mirror as separate components. Furthermore, by providing the first reflective film 31a and the second reflective film 31b on the end surface of the solid laser rod 31 that has been subjected to parallel processing with high precision, the cost of precise mechanical components and adjustment work for ensuring the parallelism of the total reflection mirror and the output mirror can be reduced.

[0050] In addition, since the first reflective film 31a and the second reflective film 31b provided on the end surface of the solid laser rod 31 are formed of an ion beam sputtering coating film having high density, the risk of damage due to moisture absorption, as with a total reflection mirror and an output mirror, is significantly reduced. Furthermore, since the solid laser rod 31 provided with the first reflective film 31a and the second reflective film 31b on the end surface constitutes the resonator 40, there is no risk of dust being mixed into the resonator 40, and the like, and the reliability of the laser device 30 is improved.

[0051] While the embodiments of the present application have been described, it should be understood that the embodiments disclosed herein are merely examples and are not to be construed as limiting in all aspects. The scope of the present application is indicated by the claims, and is intended to include all modifications within the meaning and range of equivalents of the claims.

Claims

1. A laser device that emits water with an absorption coefficient of 20 cm -1 A laser device that emits laser light of the wavelength above the above, comprising: a resonator including a cylindrical solid-state laser rod, a first reflective film provided on a first end face of the solid-state laser rod, and a second reflective film provided on a second end face of the solid-state laser rod opposite to the first end face; and Flash lamp, to excite the solid laser rod, The first reflective film and the second reflective film are ion beam sputtering coating films capable of preventing the intrusion of moisture from the outside air. The reflectivity of the first reflective film is lower than the reflectivity of the second reflective film.

2. The laser device according to claim 1, wherein The solid laser rod is a YAG crystal or a YSGG crystal to which at least one of Er, Ho, and Cr is added as an active element.

3. The laser device according to claim 1, wherein The laser light emitted by the laser device is a pulse laser light with a pulse width of 10 μs to 1000 μs.

4. The laser device according to claim 1, wherein The first reflective film and the second reflective film are made of Al2O3, Ta2O5 or SiO2.

5. The laser device according to claim 1, wherein The first reflective film and the second reflective film are multilayer films, and at least one layer of the multilayer films includes a film composed of Ta2O5.

6. The laser device according to claim 1, wherein The laser device further includes a detector for detecting the laser light transmitted through the second reflective film.

7. The laser device according to claim 6, wherein: The laser device further includes an optical filter that blocks visible light between the detector and the second end surface provided with the second reflective film.

8. The laser device according to claim 7, wherein The optical filter is made of silicon or germanium.

9. The laser device according to claim 6, wherein The laser device further includes a control substrate that controls the output of the flash lamp based on the laser light detected by the detector.

10. A laser treatment device that uses laser to treat an affected area. A laser device according to any one of claims 1 to 9 for emitting laser light.

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