JP2014014486A - Laser treatment device, and operation method and therapeutic method of laser treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide technology for determining a suitable irradiation amount of laser beams in a laser treatment device for performing the medical treatment by irradiating a laser beam to an affected part.SOLUTION: A laser treatment device 100 includes: a therapeutic laser light source 10; a monitor laser light source 11; a photo detecting part 12; a control part 2; an optical system 3; an input part 4; and an output part 6. The therapeutic laser light source 10 generates therapeutic laser light. The therapeutic laser light is irradiated to an affected part of a patient's eye 1 through the optical system 3. The monitor laser light source 11 emits monitor laser light for illuminating the interior of the patient's eye 1. The photo detecting part 12 receives the monitor laser light reflected at the ocular fundus of the patient's eye 1 through the optical system 3 to detect the intensity of the reflected light. The control part 2 compares the intensity of the reflected light detected by the photo detecting part with a reference intensity. When the detected intensity reaches the reference intensity, the control part 2 determines the end of medical treatment.

Description

  The present invention relates to a laser treatment apparatus, a method for operating a laser treatment apparatus, and a treatment method.

  There is known a laser treatment apparatus that selectively guides treatment laser light having different wavelengths to the fundus of a patient's eye according to a treatment target and photocoagulates the affected area. In such a laser treatment apparatus, the laser wavelength is selected according to the case of the patient's eye or the state of the patient's eye. In normal treatment, irradiation with green to yellow laser light is repeated, and the therapeutic effect is determined based on the coagulation spots. When the intermediate translucent body in the eye is turbid, the transmittance of the treatment laser light is lowered. Accordingly, if the desired therapeutic effect does not appear even when the power of the green to yellow laser light is increased, the red laser is selected. According to this method, there is a possibility that the green to yellow laser output is excessively increased before the red laser beam is selected.

  For example, Japanese Patent Laid-Open No. 2002-136539 (Patent Document 1) discloses a laser treatment apparatus for the purpose of appropriately selecting the wavelength of laser light. This laser treatment apparatus receives a laser beam reflected from the fundus, a wavelength selection unit that selects a wavelength of the laser beam guided to the patient's eye, a laser output setting unit that variably sets the laser output of the selected wavelength, A reflection intensity detecting means for detecting the reflection intensity of the laser light based on the output of the light receiving element, and a comparison means for comparing the detected reflection intensity of the laser light with a predetermined reference intensity. And an informing means for informing the operator of the comparison result.

JP 2002-136539 A

  In the treatment of coagulating the affected area with laser light, it is preferable that the coagulated area is as shallow and as small as possible in order to reduce the influence on the periphery of the affected area. On the other hand, the state of the affected area may vary from patient to patient. Therefore, according to the conventional method, it is difficult to determine an appropriate dose of laser light. For this reason, conventionally, for example, an operator visually determines coagulation spots and determines the irradiation amount of laser light. However, in the case of a conventional treatment apparatus, many treatment examples are required for the operator to determine an appropriate dose.

  An object of the present invention is to provide a technique for determining an appropriate dose of laser light in a laser treatment apparatus that performs treatment by irradiating an affected area with laser light.

  In one aspect of the present invention, a laser treatment apparatus includes a first laser light source that emits a first laser beam for treating an affected area, and a second laser light source that emits a second laser beam for illuminating the affected area. The first laser light source based on a comparison between the light receiving unit that receives the reflected light of the affected part due to the irradiation of the second laser light, the intensity of the reflected light received by the light receiving unit, and a predetermined reference value A control unit for controlling.

  Preferably, the second laser light source includes a semiconductor laser having an oscillation wavelength in a green wavelength region.

  Preferably, the semiconductor laser includes a gallium nitride substrate having a semipolar plane as a main surface and a light emitting element formed on the main surface of the gallium nitride substrate.

  Preferably, the semipolar plane is a plane inclined at an angle in the range of 63 degrees to 80 degrees with respect to the polar plane.

  Preferably, when the intensity of the reflected light reaches the reference value, the control unit determines that the treatment of the affected part is finished and stops the output of the first laser light from the first laser light source.

Preferably, the affected area is the fundus.
In another aspect of the present invention, a method of operating a laser treatment apparatus including a first laser light source, a second laser light source, a light receiving unit, and a control unit is provided. The operation method of the laser treatment apparatus includes a step of emitting a first laser beam for treatment of an affected area from a first laser light source, and a second laser beam for illumination of the affected area from a second laser light source. The step of emitting, the step of receiving the reflected light of the affected part by the irradiation of the second laser light by the light receiving unit, and the comparison of the intensity of the reflected light received by the light receiving unit by the control unit with a predetermined reference value And determining whether or not to emit the first laser beam.

  In yet another aspect of the invention, a treatment method is provided. The treatment method includes a step of emitting a first laser light for irradiating the affected area from a first laser light source, a step of emitting a second laser light for illuminating the affected area from a second laser light source, and The step of receiving the reflected light of the affected part by the irradiation of the second laser light by the light receiving unit, and the intensity of the reflected light received by the light receiving unit reaches a predetermined reference value, And stopping irradiation to the affected area.

  ADVANTAGE OF THE INVENTION According to this invention, the suitable irradiation amount of a laser beam can be determined in the laser treatment apparatus which irradiates a laser beam to an affected part and performs a treatment.

It is the figure which showed schematically the structure of the laser treatment apparatus according to one embodiment of this invention. It is a figure for demonstrating treatment of a retinal hiatus using the laser treatment apparatus 100 which concerns on embodiment of this invention. It is the figure which showed the affected part 1b of the patient's eye 1 shown by FIG. It is a figure which shows roughly the structure of the semiconductor laser which concerns on this Embodiment. It is the figure which showed an example of the structure of the semiconductor laser applicable to the laser treatment apparatus which concerns on this Embodiment. 1 is a schematic structural diagram of a refractive index guided semiconductor laser. FIG. It is a flowchart for demonstrating an example of the operation | movement method of the laser treatment apparatus 100 which concerns on embodiment of this invention. It is a flowchart for demonstrating the other example of the operation | movement method of the laser treatment apparatus 100 which concerns on embodiment of this invention. It is a schematic cross section of an affected part explaining an example in the case of irradiating an affected part with a treatment laser beam and a monitor laser beam simultaneously. It is the figure which showed the outline of the measuring system for measuring the change of the intensity | strength of the regular reflection light accompanying the photocoagulation of the affected part. It is the figure which showed the photocoagulation sample used for experiment with the measurement system shown in FIG. It is the figure which showed the result of having measured the change of the reflectance using the measurement system shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a diagram schematically showing a configuration of a laser therapy apparatus according to an embodiment of the present invention. Referring to FIG. 1, a laser treatment apparatus 100 according to an embodiment of the present invention is an apparatus for treatment of a patient's eye 1. The laser treatment apparatus 100 includes a treatment laser light source 10, a monitor laser light source 11, a light receiving unit 12, a control unit 2, an optical system 3, an input unit 4, and an output unit 6.

  The treatment laser light source 10 generates treatment laser light. The treatment laser light is irradiated to the affected part of the patient's eye 1 through the optical system 3. The kind of treatment laser light source 10 is not particularly limited.

  The monitor laser light source 11 emits monitor laser light for illuminating the inside of the patient's eye 1. The monitor laser light is introduced into the patient's eye 1 through the optical system 3. It is preferable to use green laser light as the monitor laser light. Green is defined as a wavelength range of 488 nm to 577 nm, for example. More preferably, in the present embodiment, the wavelength of the green laser light is in the wavelength range of 488 nm to 577 nm. The intensity of the monitor laser light source 11 is sufficiently smaller than the intensity of the treatment laser light.

  In one embodiment, the optical axis of the treatment laser light and the optical axis of the monitor laser light are the same. Thereby, monitor laser light can also be utilized as aiming light for determining the irradiation position of treatment laser light. However, the laser treatment apparatus 100 may include an aiming light source separately from the monitor laser light source.

  The light receiving unit 12 receives the monitor laser light reflected from the fundus of the patient's eye 1 through the optical system 3 and detects the intensity of the reflected light. The light receiving unit 12 is an imaging device such as a CCD (charge coupled device) image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) image sensor.

  The control unit 2 controls the overall operation of the laser treatment apparatus 100. The control unit 2 compares the intensity of the reflected light detected by the light receiving unit with a reference intensity. When the detected intensity does not reach the reference intensity, the control unit 2 determines that the treatment is not yet finished. When the detected intensity reaches the reference intensity, the control unit 2 determines that the treatment is finished. “The detected intensity reaches the reference intensity” may be either when the detected intensity increases to reach the reference intensity or when the detected intensity decreases to reach the reference intensity.

  In one embodiment, the laser treatment apparatus 100 is configured such that the light receiving unit 12 receives scattered and reflected light from the fundus of the patient's eye 1. In this configuration, the reflectance increases as photocoagulation of the affected area proceeds. That is, the intensity of scattered reflected light increases. When the intensity of the scattered reflected light increases and reaches a certain reference intensity, it is determined that the treatment is finished. On the other hand, the laser treatment apparatus 100 can be configured to observe specularly reflected light from the fundus of the patient's eye 1. According to this configuration, both the case where the reflectance increases as the photocoagulation of the affected area progresses and the case where the reflectance decreases can be considered. When the reflectance increases, as described above, it is determined that the treatment is completed when the intensity of the reflected light reaches a certain reference intensity. On the other hand, when the reflectance decreases, it is determined that the treatment is completed when the intensity of the reflected light reaches a certain reference intensity.

  The input unit 4 receives various inputs from the operator. For example, the input unit 4 accepts various operations by the operator (irradiation of treatment laser light, irradiation of monitor laser light, etc.). The output unit 6 outputs, for example, information or instructions input to the input unit 4, information indicating that treatment is in progress or treatment, and the like. The output unit 6 includes a display device, for example. The output unit 6 may include a printer in addition to the display device or in place of the display device.

  In the configuration shown in FIG. 1, the input unit 4 and the output unit 6 are shown independently. However, these may be integrated. For example, an apparatus having functions of an input unit and a display unit such as a touch panel display can be applied to the laser treatment apparatus 100. The control unit 2, the input unit 4, and the output unit 6 may be integrated.

  The laser treatment apparatus 100 according to the embodiment of the present invention is used for laser photocoagulation treatment. Laser photocoagulation therapy is applied for the treatment of diabetic retinopathy, retinal vein occlusion and retinal tear, for example. Below, treatment of a retinal hiatus is demonstrated typically.

  FIG. 2 is a diagram for explaining treatment of a retinal hiatus using the laser treatment apparatus 100 according to the embodiment of the present invention. Referring to FIG. 2, the retinal tear is a symptom in which a hole or a tear is formed in the retina 1a. The affected part 1b shown in FIG. 2 is a part of the retina 1a where a retinal tear has occurred. When the retinal hiatus is left, the liquid component of the vitreous body 1c may enter the hole of the retina 1a, and the retina 1a may gradually peel off. From the viewpoint of preventing retinal detachment, it is important to treat the eye at the stage of retinal tear.

  As shown in FIG. 2, in the laser photocoagulation treatment, the treatment laser beam 10a is irradiated to the affected part 1b. FIG. 3 is a view showing an affected area 1b of the patient's eye 1 shown in FIG. With reference to FIG. 2 and FIG. 3, treatment laser light is irradiated around the hiatus 1d. Thereby, the circumference | surroundings of the crack part 1d are baked and hardened. The coagulation spot 21 corresponds to the irradiation trace of the treatment laser beam.

  In this embodiment, after irradiating the affected part 1b with the treatment laser light, the affected part 1b is irradiated with the monitor laser light. The monitor laser light is reflected at the affected part 1b. The light receiving unit 12 receives the reflected light. The intensity of the reflected light changes (increases or decreases) as the periphery of the fissure hole portion 1d is baked and hardened. In this embodiment, based on the intensity of the reflected light, it is determined whether or not the irradiation amount of the treatment laser light is appropriate.

  As described above, the monitor laser beam is a green laser beam. Since blood vessels are stretched around the living tissue, the living tissue is red due to the red blood cells in the blood regardless of the affected part or the normal part. Therefore, although the portion illuminated in red is difficult to see, the portion illuminated in green can be favorably highlighted. Therefore, if green laser light is used as the monitor laser light, the green laser light can be used as aiming light. On the other hand, light scattering increases as the wavelength of light decreases. Therefore, from the viewpoint of capturing reflected light, it is preferable that the wavelength of the monitor laser light is short. However, blue light is easily absorbed by the surface layer of the retina 1a. Conversely, when red monitor laser light is used, the monitor laser light reaches a deep portion of the retina 1a because the wavelength of the laser light is long. Also in this case, since the light scattering is larger as the light wavelength is shorter, the intensity of the scattered light on the surface layer of the retina 1a is reduced. From these viewpoints, it is effective to use green laser light as the monitor laser light.

  In this embodiment, the monitor laser light source 11 is a green semiconductor laser. FIG. 4 is a diagram schematically showing the structure of the semiconductor laser according to the present embodiment. As for the negative index, “−” (bar) is attached on the number in crystallography, but in this specification, a negative sign is attached before the number.

  Referring to FIG. 4, monitor laser light source (semiconductor laser) 11 includes a substrate 51, a GaN (gallium nitride) based semiconductor epitaxial region 55, and an active layer 57.

  The substrate 51 is made of a first GaN-based semiconductor and can be, for example, GaN, InGaN, AlGaN, or the like. Since GaN is a binary compound GaN-based semiconductor, it can provide good crystal quality and a stable substrate main surface. The first GaN-based semiconductor can be made of, for example, AlN.

  The c-plane of the substrate 51 extends along the plane Sc shown in FIG. On the plane Sc, a coordinate system CR (c-axis, a-axis, m-axis) is shown. The main surface 51a of the substrate 51 is a semipolar surface, and is a surface inclined by a predetermined angle with respect to the polar surface, that is, the c-plane of the GaN crystal. In this embodiment, the main surface 51a of the substrate 51 is 63 degrees in the direction of the m-axis of the first GaN-based semiconductor from the plane orthogonal to the reference axis Cx extending along the c-axis of the first GaN-based semiconductor. It is inclined at an inclination angle in the range of less than 80 degrees. The inclination angle α is defined by the angle formed between the normal vector VN of the main surface 51a of the substrate 51 and the reference axis Cx. In the present embodiment, this angle is equal to the angle formed by the vector VC + and the vector VN.

  The GaN-based semiconductor epitaxial region 55 is provided on the main surface 51a. The active layer 57 includes at least one semiconductor epitaxial layer 59. The semiconductor epitaxial layer 59 is provided on the GaN-based semiconductor epitaxial region 55. The semiconductor epitaxial layer 59 is made of a second GaN-based semiconductor. The second GaN-based semiconductor contains indium (In) as a constituent element. The film thickness direction of the semiconductor epitaxial layer 59 is inclined with respect to the reference axis Cx. The reference axis Cx can be oriented in the direction of the [0001] axis of the first GaN-based semiconductor or the direction of the [000-1] axis. In the present embodiment, the reference axis Cx is oriented in the direction indicated by the vector VC +. As a result, the vector VC- is oriented in the direction of the [000-1] axis.

  In the substrate 51, the main surface 51a is made of a surface morphology M1 including a plurality of narrow terraces as shown in FIG. A GaN-based semiconductor epitaxial region 55 is provided on the substrate 51. The crystal axis of the GaN-based semiconductor epitaxial region 55 inherits the crystal axis of the substrate 51. Therefore, the main surface 55a of the GaN-based semiconductor epitaxial region 55 is also inclined at an angle in the range of 63 degrees or more and less than 80 degrees in the m-axis direction from the plane orthogonal to the reference axis Cx. Therefore, the main surface 55a of the GaN-based semiconductor epitaxial region 55 also has a surface morphology M2 including a plurality of narrow terraces. The arrangement of these terraces constitutes a microstep. Since the terrace in the above angle range is narrow, nonuniformity of the In composition is unlikely to occur over a plurality of terraces. Therefore, a decrease in light emission characteristics due to In segregation is suppressed.

  In one embodiment, the GaN-based semiconductor epitaxial region 55 includes an n-type cladding layer 41 and a light guide layer 43a arranged in the Ax axis direction (Z direction). The n-type cladding layer 41 can be made of, for example, AlGaN or GaN. The light guide layer 43a can be made of undoped InGaN, for example. Since the n-type clad layer 41 and the light guide layer 43a are epitaxially grown on the main surface 51a of the substrate 51, the main surface 41a of the n-type clad layer 41 and the main surface 43c of the light guide layer 43a (in this embodiment, the main surface) 55a) each have a surface morphology with a terrace structure. The surface morphology has a plurality of microsteps arranged in the c-axis tilt direction, and these microsteps extend in a direction intersecting the tilt direction. The main constituent surfaces of the microstep include at least an m-plane, a (20-21) plane, a (10-11) plane, and the like. In the above configuration surface and step end, In is well taken in.

  The GaN-based semiconductor region 56 includes a light guide layer 43b, an electron block layer 45, a cladding layer 47, and a contact layer 49 arranged in the Z direction. The light guide layer 43b can be made of undoped InGaN, for example. The electron block layer 45 can be made of, for example, AlGaN. The clad layer 47 can be made of, for example, p-type AlGaN or p-type GaN. The contact layer 49 can be made of, for example, p-type GaN or p-type AlGaN.

  The monitor laser light source (semiconductor laser) 11 can include a first electrode 61 (for example, an anode) provided on the contact layer 49. The first electrode 61 is connected to the contact layer 49 through a stripe window of the insulating film 63 covering the contact layer 49. For example, Ni / Au is used as the first electrode 61. The monitor laser light source (semiconductor laser) 11 can include a second electrode 65 (for example, a cathode) provided on the back surface 51 b of the substrate 51. The second electrode 65 is made of, for example, Ti / Al.

  The active layer 57 generates light L <b> 1 in response to an external voltage applied to both ends of the electrodes 61 and 65. In the present embodiment, the semiconductor laser is an edge emitting element. In the active layer 57, the Z component of the piezoelectric field (component related to the direction of the predetermined axis Ax) is opposite to the direction from the GaN-based semiconductor region 56 toward the GaN-based semiconductor epitaxial region 55. According to this semiconductor laser, since the Z component of the piezoelectric field is opposite to the direction of the electric field due to the external voltage applied to both ends of the electrodes 61 and 65, the shift of the emission wavelength is reduced.

FIG. 4 shows the off angle A _OFF . This off angle A _OFF is an angle in the XZ plane. The off angle A _OFF in the a-axis direction of the substrate 51 is preferably a finite value. The off angle A _{OFF in the} a-axis direction improves the surface morphology of the epitaxial region. The range of the off angle A _OFF can be, for example, a range of −3 degrees or more and +3 degrees or less. Specifically, the range of the off angle A _OFF is, for example, −3 degrees or more and −0.1 degrees or less and +0. It is preferably in the range of 1 degree or more and +3 degree or less. When the range of the off angle A _OFF is, for example, in a range of not less than −0.4 degrees and not more than −0.1 degrees and not less than +0.1 degrees and not more than +0.4 degrees, the surface morphology is further improved.

The active layer 57 is preferably provided so as to generate an emission wavelength of 600 nm or less. An inclination angle in a range of 63 degrees or more and less than 80 degrees is effective in a light emission wavelength range of 480 nm to 600 nm. When this wavelength is reached, the In composition of the well layer is considerably increased, and the emission intensity is greatly reduced on the surface with large In segregation such as c-plane, m-plane and (10-11) plane. On the other hand, since the In segregation is small in this angular range, the decrease in emission intensity is small even in the long wavelength region of 480 nm or more. The range of the thickness of the well layer can be, for example, 0.5 nm to 10 nm. The range of the In composition X of the In _X Ga _1-X N well layer can be, for example, 0.01 to 0.50.

  The active layer 57 can have the quantum well structure 31. The quantum well structure 31 includes well layers 33 and barrier layers 35 that are alternately arranged in a direction of a predetermined axis Ax. In this embodiment, the well layer 33 is composed of a semiconductor epitaxial layer 59. The well layer 33 is made of, for example, InGaN, InAlGaN, or the like. The barrier layer 35 is made of a GaN-based semiconductor. The GaN-based semiconductor can be made of, for example, GaN, InGaN, AlGaN, or the like. The GaN-based semiconductor epitaxial region 55, the active layer 57, and the GaN-based semiconductor region 56 are arranged in the direction of a predetermined axis Ax. The direction of the reference axis Cx is different from the direction of the predetermined axis Ax.

  FIG. 5 is a diagram showing an example of a semiconductor laser structure applicable to the laser treatment apparatus according to the present embodiment. Referring to FIG. 5, a semiconductor laser 11A includes a GaN substrate 120 having a (20-21) plane, and a semiconductor light emitting element formed on the main surface ((20-21) plane) of the GaN substrate 120 by epitaxial growth. Have This semiconductor light emitting device includes the following layers.

n-type buffer layer 121a: Si-doped GaN, growth temperature 1050 ° C., thickness 1.5 μm;
n-type cladding layer 121b: Si-doped AlGaN, growth temperature 1050 ° C., thickness 500 nm, Al composition 0.04;
Optical guide layer 122a: undoped GaN, growth temperature 840 ° C., thickness 50 nm;
Optical guide layer 122b: undoped InGaN, growth temperature 840 ° C., thickness 65 nm, In composition 0.03;
Active layer 123;
Barrier layer 123a: undoped GaN, growth temperature 870 ° C., thickness 15 nm;
Well layer 123b: undoped InGaN, growth temperature 750 ° C., thickness 3 nm, In composition 0.22;
Optical guide layer 124b: undoped InGaN, growth temperature 840 ° C., thickness 65 nm, In composition 0.03;
Optical guide layer 124a: undoped GaN, growth temperature 840 ° C., thickness 50 nm;
Electron blocking layer 125: Mg-doped AlGaN, growth temperature 1000 ° C., thickness 20 nm, Al composition 0.12;
p-type cladding layer 126: Mg-doped AlGaN, growth temperature 1000 ° C., thickness 400 nm, Al composition 0.06;
p-type contact layer 127: Mg-doped GaN, growth temperature 1000 ° C., thickness 50 nm.

  An insulating film 128 such as a silicon oxide film is deposited on the p-type contact layer 127. A stripe window is formed in the insulating film 128. The p-electrode (Ni / Au) 129a is in contact with the p-type contact layer 127 through the stripe window. On the back surface of the GaN substrate 120, an n-electrode (Ni / Al) 129b is formed and a pad electrode (Ti / Au) is deposited.

The substrate product produced by these processes is cleaved on the a-plane at intervals of 800 μm, for example. A reflective film made of a SiO ₂ / TiO ₂ multilayer film is formed on the a-plane cleavage plane for the resonator. Thereby, a gain waveguide laser diode is manufactured. For example, the reflectance of the front end face is 80%, and the reflectance of the rear end face is 95%.

The oscillation wavelength of the semiconductor laser having the above-described configuration, that is, a laser diode is, for example, 520 nm. However, the oscillation wavelength of the semiconductor laser can be adjusted by changing the composition ratio of In and Ga in the well layer 123b. For example, the threshold current of the laser diode is 20 kA / cm ² and the operating voltage (current value: 1600 mA) is 7.2 volts.

  Note that the present invention is not limited to the gain waveguide semiconductor laser shown in FIG. 5, and a refractive index waveguide semiconductor laser can also be applied to this embodiment. FIG. 6 is a schematic structural diagram of a refractive index guided semiconductor laser. Referring to FIG. 6, a semiconductor laser 11B is formed in the shape of a ridge waveguide, a GaN substrate 130 having a (20-21) plane, an n-type cladding layer 131, an active layer 133 including a barrier layer and a well layer. The p-type cladding layer 136, the p-type contact layer 137, the insulating film 138, the p-electrode 139a, and the n-electrode 139b are provided.

  FIG. 7 is a flowchart for explaining an example of the operation method of the laser treatment apparatus 100 according to the embodiment of the present invention. The processing at each step is controlled by the control unit 2. The operation of the laser treatment apparatus 100 is synonymous with treatment using the laser treatment apparatus 100.

  Referring to FIG. 7, in step S1, the irradiation position of the treatment laser light is adjusted. For example, when the monitor laser beam is also used as the aiming beam, the laser treatment apparatus 100 adjusts the direction of the optical axis of the monitor laser beam. As a result, the optical axis of the treatment laser beam is directed to the affected area 1b. In step S2, the treatment laser light source 10 irradiates the affected part 1b with the treatment laser beam. The treatment laser light is emitted from the treatment laser light source 10 by the operation of the operator.

  In step S3, the monitor laser light source 11 irradiates the affected part 1b of the patient's eye 1 with the monitor laser light by the operation of the operator. In step S4, the light receiving unit 12 receives the reflected light from the affected part 1b. The light receiving unit 12 outputs a signal indicating the intensity of the received reflected light to the control unit 2.

  In step S5, the control unit 2 compares the intensity of the reflected light with a reference intensity (predetermined reference value). The reference intensity may be fixed or variable. If the reference intensity is variable, for example, the operator can determine the reference intensity.

  In step S6, the control unit 2 determines whether or not the intensity of the reflected light has reached the reference intensity. If the intensity of the reflected light has reached the reference intensity (YES in step S6), the process proceeds to step S7. In step S7, the control unit 2 determines that the treatment has ended. In this case, the control unit 2 may output information (for example, a message) indicating that the treatment has ended to the output unit 6. Or the control part 2 may prohibit operation of an operator so that a treatment laser beam may not be emitted.

  On the other hand, when the intensity of the reflected light does not reach the reference intensity (NO in step S6), the process proceeds to step S8. In step S8, the control unit 2 determines that the treatment has not ended. In this case, the process returns to step S1. Note that the determinations in steps S6, S7, and S8 may be executed by the operator.

  In the operation method shown in FIG. 7, the monitor laser beam is irradiated after the treatment laser beam is irradiated to the affected area. That is, the monitor laser beam is not irradiated simultaneously with the treatment laser beam. However, the operation method of the laser treatment apparatus 100 according to the embodiment of the present invention is not limited in this way.

  FIG. 8 is a flowchart for explaining another example of the operation method of the laser treatment apparatus 100 according to the embodiment of the present invention. Referring to FIGS. 7 and 8, the process of step S2A is executed instead of the processes of steps S2 and S3. In step S2A, the monitor laser beam is applied to the affected area simultaneously with the treatment laser beam. In this way, it is also possible to monitor the degree of coagulation of the affected area with the reflected light of the monitor laser light while irradiating the treatment laser light. Since the processing of the other steps shown in FIG. 8 is the same as the processing of the corresponding steps shown in FIG. 7, the following description will not be repeated.

  When simultaneously irradiating the treatment laser light and the monitor laser light, the optical axis of the treatment laser light and the optical axis of the monitor laser light may be the same or may be shifted from each other. When the optical axes of both laser beams are the same, for example, the wavelengths of the treatment laser beam and the monitor laser beam are made different. Furthermore, the laser treatment apparatus 100 is configured such that the light receiving unit 12 receives only the monitor laser light. For example, only the monitor laser light may be received by performing spectroscopy with the light receiving unit 12, or a wavelength filter that selectively transmits the monitor laser light may be provided in front of the light receiving unit 12.

  FIG. 9 is a schematic cross-sectional view of an affected part, explaining an example in which treatment laser light and monitor laser light are simultaneously irradiated to the affected part. When the optical axis of the treatment laser light and the optical axis of the monitor laser light are shifted from each other, for example, as shown in FIG. 9, the treatment laser light and the monitor laser light may be irradiated. In order to explain the cross section of the affected area, FIG. 9 schematically shows cross sections of the retina 1a and the choroid 1e. By irradiating the affected part with the treatment laser light, the coagulation part 1f is formed inside the retina 1a. At the same time, the degree of coagulation of the affected area is monitored by the regular reflection light of the monitor laser beam at the coagulation part 1f.

  In the case of the configuration shown in FIG. 9, the reflectance may decrease due to the scattering of the monitor laser light at the coagulation portion 1 f. That is, the intensity of specularly reflected light may decrease as photocoagulation of the affected area proceeds. In this case, when the intensity of the specularly reflected light decreases and reaches a certain reference intensity, it can be determined that the treatment has ended.

  FIG. 10 is a diagram showing an outline of a measurement system for measuring a change in intensity of specularly reflected light accompanying photocoagulation of an affected area. Referring to FIG. 10, the measurement system includes a semiconductor laser 210, a lens system 220, a half mirror 230, an objective lens 240, an optical path switching mirror 250, a CCD 260, a lens 270, and a power meter 280. . Laser light from the semiconductor laser 210 passes through the lens system 220 and is guided to the objective lens 240 by the half mirror 230. The laser beam emitted from the objective lens 240 is applied to the sample 300 placed on the sample table 310. The specularly reflected light from the sample 300 passes through the objective lens 240 and the half mirror 230 and is sent to the CCD 260 or the power meter 280 by the optical path switching mirror 250. In the configuration shown in FIG. 10, the optical axis of the laser light from the semiconductor laser 210 and the optical axis of the reflected light from the sample 300 are the same between the half mirror 230 and the sample 300. That is, the regular reflection light from the sample 300 is received by the CCD 260 or the power monitor 280.

  In the experiment, a semiconductor laser having an oscillation wavelength of 530 nm (green) and a semiconductor laser having an oscillation wavelength of 658 nm (red) were used as the semiconductor laser 210. As the sample 300, a bird lever having an absorption coefficient close to that of the human retina and choroid was used as a sample simulating the human retina.

FIG. 11 is a view showing a photocoagulation sample used in the experiment in the measurement system shown in FIG. Referring to FIG. 11, laser light from a CW laser light source having an oscillation wavelength of 532 nm was used. The sample was irradiated with laser light while changing the irradiation time from 30 seconds to 120 seconds by 30 seconds. The output of the CW laser light source is adjusted to 70 mW at the sample irradiation unit, the beam diameter of the laser light irradiated to the sample (the part where the energy becomes 1 / e ² ) is 2.5 mm, and the power of the laser light The density was 1.43 W / cm ² .

  FIG. 12 is a diagram showing a result of measuring a change in reflectance using the measurement system shown in FIG. Referring to FIG. 12, when a semiconductor laser having an oscillation wavelength of 530 nm (green) is used, the reflectance after irradiating laser light for 120 seconds is 0 with respect to the original reflectance (irradiation time 0 seconds). .014 decreased. On the other hand, when a semiconductor laser having an oscillation wavelength of 658 nm (red) was used, the reflectivity after irradiation with laser light for 120 seconds decreased by 0.005 with respect to the original reflectivity (irradiation time 0 seconds). FIG. 12 shows that the intensity of specularly reflected light may decrease as photocoagulation of the affected area proceeds. Furthermore, FIG. 12 shows that the amount of decrease in reflectance is greater when the sample is irradiated with green laser light than when the sample is irradiated with red laser light. This indicates that the shorter the wavelength of the laser light, the larger the light scattering, and the less the intensity of the specularly reflected light from the photocoagulation part of the retina.

  As described above, according to this embodiment, it is determined whether or not to end treatment based on the reflected light intensity of the monitor laser light. The reflected light intensity increases as the affected area is baked. By appropriately setting the reference intensity, it is possible to treat only a shallow and small area near the affected area 1b. Therefore, according to this embodiment, the affected area can be treated with an appropriate laser dose.

  Note that this embodiment does not exclude the visual judgment of coagulation spots. Subsequent to the process of step S7, the end of the treatment may be determined by visual observation of the coagulation spots.

  Furthermore, according to this embodiment, the green laser light source is used as the monitor laser light source. This is advantageous in that the green laser light can be used as the aiming light and the intensity of the scattered light is large and the sensitivity is high.

  Further, a semiconductor laser is used as a monitor laser light source (that is, a green laser light source). The semiconductor laser includes a semiconductor element fabricated by epitaxial growth on a GaN single crystal. By emitting green laser light from the semiconductor laser, green laser light can be generated without using a wavelength conversion element. Thereby, the increase in the cost of a treatment apparatus can be prevented.

  In this embodiment, the fundus of the patient's eye is illustrated as an example of the affected part. However, the laser treatment apparatus according to the present invention can be used in a scene in which the intensity of reflected light of the monitor laser light at the affected part increases by repeatedly irradiating the affected part with the treatment laser light. Therefore, the laser treatment apparatus according to the present invention is not limited to the treatment of a specific affected area (for example, the fundus of a patient's eye), and can be applied to the treatment of various affected areas.

  The embodiment disclosed this time must be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 patient eye, 1a retina, 1b affected part, 1c vitreous body, 1d hiatus, 1e choroid, 1f coagulation part, 2 control part, 3 optical system, 4 input part, 6 output part, 10 treatment laser light source, 10a treatment laser light , 11 monitor laser light source, 11A, 11B semiconductor laser, 12 light receiving part, 21 coagulation spot, 31 quantum well structure, 33, 123b well layer, 35, 123a barrier layer, 41, 121b, 131 n-type cladding layer, 41a, 43c , 51a, 55a main surface, 43a, 43b, 122a, 122b, 124a, 124b light guide layer, 45, 125 electron block layer, 47 cladding layer, 49 contact layer, 51, 120, 130 substrate, 51b back surface, 55 GaN system Semiconductor epitaxial region, 56 GaN-based semiconductor region, 57, 123, 133 active layer, DESCRIPTION OF SYMBOLS 9 Semiconductor epitaxial layer, 61 1st electrode, 63,128,138 Insulating film, 65 2nd electrode, 100 Laser treatment apparatus, 121a n-type buffer layer, 126,136 p-type clad layer, 127,137 p-type contact Layer, 210 semiconductor laser, 220 lens system, 230 half mirror, 240 objective lens, 250 optical path switching mirror, 260 CCD, 270 lens, 280 power meter, 300 samples, 310 sample stage.

Claims (8)

A first laser light source emitting a first laser beam for treatment of the affected area;
A second laser light source emitting a second laser beam for illuminating the affected area;
A light receiving unit that receives reflected light of the affected part by irradiation of the second laser light;
A laser treatment apparatus comprising: a control unit that controls the first laser light source based on a comparison between an intensity of the reflected light received by the light receiving unit and a predetermined reference value.   The laser treatment apparatus according to claim 1, wherein the second laser light source includes a semiconductor laser having an oscillation wavelength in a green wavelength region. The semiconductor laser is
A gallium nitride substrate having a semipolar surface as a main surface;
The laser treatment apparatus according to claim 2, further comprising: a light emitting element formed on the main surface of the gallium nitride substrate.   The laser treatment apparatus according to claim 3, wherein the semipolar plane is a plane inclined at an angle within a range of 63 degrees or greater and 80 degrees or less with respect to the polar plane.   When the intensity of the reflected light reaches the reference value, the control unit determines that the treatment of the affected part is finished, and stops the output of the first laser light from the first laser light source. The laser therapy apparatus of any one of Claims 1-4.   The laser treatment apparatus according to claim 1, wherein the affected part is a fundus. An operation method of a laser treatment apparatus including a first laser light source, a second laser light source, a light receiving unit, and a control unit,
Emitting a first laser beam for treating the affected area from the first laser light source;
Emitting a second laser beam for illuminating the affected area from the second laser light source;
Receiving the reflected light of the affected part by the irradiation of the second laser light by the light receiving part;
Determining whether or not to emit the first laser light based on a comparison between an intensity of the reflected light received by the light receiving unit and a predetermined reference value by the control unit. The method of operation of the treatment device. Emitting a first laser beam for irradiating the affected area from a first laser light source;
Emitting a second laser beam for illuminating the affected area from a second laser light source;
Receiving a reflected light of the affected part by the irradiation of the second laser light by a light receiving part;
And a step of stopping irradiation of the affected part with the first laser beam when the intensity of the reflected light received by the light receiving part reaches a predetermined reference value.