JPH05300914A - Output attenuator for laser treatment system - Google Patents

Abstract

PURPOSE:To obtain high-output and low-output laser beams for treatment by using a single laser oscillation by disposing a demultiplexing means for optically demultiplexing the laser beam oscillated from a laser oscillator at a prescribed ratio into an optical path for the laser beam in such a manner that this means can advance and retreat. CONSTITUTION:A dichroic prism 14 formed with such multilayered coats 13 which allows nearly 100% transmission of a guiding beam and branches the laser beam 3 oscillated from the laser oscillator 1 at the prescribed ratio is disposed in the optical path between the laser oscillator 1 and a prism 9 for output monitor. This dichroic prism 14 is driven by a solenoid 15 so as to be freely moved from the optical path to the outside of the optical path or from the outside of the optical path onto the optical path. The laser beam demultiplexed by the prism 14 is condensed to a microaperture 23 of a hollow absorber 21 having a spherical inside surface partly formed with a plane part 20 by a condenser lens 19 and is then diffused into the absorber 21. The most of the energy thereof is absorbed while the laser beam repeats many times of reflection within the absorber 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output attenuating device for attenuating laser light oscillated by a laser oscillator in a laser treatment device such as a laser scalpel and a laser coagulator.

[0002]

2. Description of the Related Art There are laser scalpels, laser coagulators and the like as laser treatment devices utilizing the energy of laser light. For example, the laser scalpel is well known as YA.
G laser light or CO ₂ laser light is used to perform incision, coagulation, hemostasis or incision of affected areas such as polyps and ulcers, and vaporization elimination treatment using a G laser light or a CO ₂ laser light. It is composed of a light guide path that guides the laser light generated by the laser generator to a target portion.

In this laser scalpel, recently, a transparent sapphire chip is connected to the emitting end of a lightweight and flexible laser fiber, and the tip of the sapphire chip is brought into contact with the affected area under observation with an endoscope to perform YAG. Contact irradiation therapy in which a laser beam is irradiated to coagulate or incise an affected tissue has been put into practical use.

In such contact irradiation therapy, the irradiation energy density of the YAG laser light is much higher than that in the conventional non-contact therapy, and the reflection and scattering on the surface tissue of the affected area can be suppressed. Even with a low output, a sufficient therapeutic effect can be expected. For example, for coagulation, non-contact therapy required an output of 30 W or higher, whereas contact irradiation therapy required an output of 6 W or less, which was about 1/5 of that output, and was equivalent to non-contact therapy. The effect of can be obtained.

On the other hand, when this YAG laser light is used for non-contact therapy for the purpose of hemostasis, a high output of about 100 W is required. However, in the conventional YAG laser treatment apparatus having an output of 100 W, the threshold of population inversion for starting laser oscillation corresponds to an output near 10 W, so that stable oscillation cannot be performed at a low output of 10 W or less. That is, even if the laser excitation lamp is current-controlled so as to have a low output, there is a problem that laser oscillation does not occur, or even if it oscillates, the output becomes very unstable.

As a first method for solving such a problem, conventionally, two YAG laser treatment devices of a high output type and a low output type are prepared in an operating room, and the treatment device is selected according to the contents of the treatment. It was designed to be used properly.

As a second method, a built-in light-shielding device in which a chopper having a light-transmitting portion and a light-shielding portion alternately provided around a rotating disk at an appropriate ratio is made movable in and out of a laser optical path,
A laser treatment apparatus has been proposed in which most of the YAG laser light is blocked by a chopper only in the case of contact irradiation therapy and a low output is obtained by passing a part of the light.

[0008]

In the above-mentioned first conventional method, the floor area for installation is large and the degree of freedom of the operator, assistant, nurse, etc. is limited, and moreover, there are two units depending on the contents of the treatment. However, there is a drawback in that the treatment device must be properly used properly, and the overall price becomes high.

In the second method, the apparent average output is low, but the split pulsed laser light itself has very high output and high energy density. The sapphire chip connected to the emitting end has the drawback of cracking and puncturing the irradiated area, and most of the high-power YAG laser light of continuous oscillation of about 100 W is blocked by the chopper. Therefore, the YAG laser light absorbed by the light-shielding portion of the chopper heats the chopper portion, and as a result, not only does the chopper malfunction but also the generated heat reduces the stability of the laser oscillator, Reflected at the edge of the light blocking part or the light blocking part and the light transmitting part,
The scattered YAG laser light may damage a part of the laser oscillator or the power supply, or the reflected or scattered YAG laser light may leak to the outside of the laser treatment device and be known to the skin or eyes of the operator, assistant, nurse, etc. It had a big drawback in practical use that it was damaged before it arrived.

The present invention has been made to solve the above problems, and an output attenuation that enables to obtain both high-power and low-power therapeutic laser light by using a single laser oscillator. The purpose is to provide a device.

A second object of the present invention is to provide an output attenuator which is not in the form of pulse but in the form of continuous oscillation and which can set the output power to a desired value.

A third object of the present invention is to provide an output attenuator which does not damage the skin or eyes of an operator, an assistant, a nurse or the like due to reflection, scattering or the like.

[0013]

In the present invention, in order to achieve the above object, a demultiplexer for optically demultiplexing a laser beam at a predetermined ratio in an optical path of a laser beam oscillated from a laser oscillator. The means is arranged so that it can move back and forth.

Then, the demultiplexing means, for example, the laser light demultiplexed by the dichroic prism is completely absorbed by the absorber by the condenser lens. In this case, the receiving body is preferably a hollow body having a spherical inner surface so that the laser light from the condenser lens enters the absorbing body through the minute aperture and is absorbed.

Further, the oscillation output of the laser oscillator can be adjusted automatically or manually.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are block diagrams showing an embodiment of the output attenuator of the present invention. FIG. 1 shows a case of using for contact irradiation therapy, and FIG. 2 shows a case of using for non-contact therapy.

In the figure, reference numeral 1 is a laser oscillator, which is supplied with power from a laser control circuit 2 to operate and oscillates a laser beam 3. This laser light 3
When performing contact irradiation therapy, as shown in FIG.
Incident end face 5 of laser fiber 5 through condenser lens system 4
The light is focused on a and emitted from the tip of the sapphire chip 6 connected to the emission end face 5b. On the other hand, in the case of normal non-contact therapy, laser light is emitted from the emission end surface 5b of the laser fiber 5 as shown in FIG.

In the optical path between the laser oscillator 1 and the condenser lens system 4, a right-angled prism 8 is attached by an optical adhesive 7.
An output-monitoring prism 9 is attached to each other.
Due to the difference in refractive index between the optical adhesive 7 and the rectangular prism 8, a very small amount of laser light is reflected, passes through the filter 10 and is incident on the light receiving surface of the output detector 11. The filter 10 is
It has the property of selectively passing only the required wavelength band. The output of the output detector 11 is amplified by the amplifier 12 and then input to the laser control circuit 2.

Further, in the optical path between the laser oscillator 1 and the output monitor prism 9, guide light (usually He-Ne) is provided.
Laser light, which is not shown in the figure) is almost 100% transmitted,
A dichroic prism 14 provided with a multilayer film coat 13 for demultiplexing the laser light 3 oscillated from the laser oscillator 1 at a predetermined ratio is provided. The dichroic prism 14 can be moved from the optical path to the outside of the optical path and from the outside of the optical path to the optical path by driving the solenoid 15.

The output setting device 16 is a device for setting a laser output value desired by the operator as a laser treatment device, and the display device 17 displays the set output value. The output value set by the output setting device 16 is sent to the mode determination circuit 18. The mode discriminating circuit 18 compares the threshold value determined according to the demultiplexing rate of the dichroic prism 14 with the set output value from the output setting device 16, and interposes the dichroic prism 14 on the optical path of the laser beam 3. This is a circuit for determining whether or not. That is, the mode determination circuit 18 is also a circuit that determines whether the laser treatment apparatus is used for non-contact therapy or contact irradiation therapy, from the set output value of the output setting device 16. When the set output value is lower than the threshold value, the mode discriminating circuit 18 drives the solenoid 15 and advances the dichroic prism 14 onto the optical path of the laser light 3.

The laser beam demultiplexed by the prism 14 is condensed by a condenser lens 19 into a minute opening 23 of a hollow absorber 21 having a spherical inner surface, a part of which is a plane portion 20, and then the absorber. Almost all of the energy is absorbed while being diffused in 21 and repeating a large number of reflections in the absorber 21. The minute opening 23 is opened at a position away from the center of the flat surface portion 20 so that the laser light entering the inside is reflected many times inside. In addition, on the entire inner circumference of the absorber 21,
An absorbing material 24 that absorbs laser light is applied.

The discrimination signal from the mode discrimination circuit 18 is input to the attenuation rate setting circuit 25. The attenuation rate setting circuit 25
According to the discrimination signal, the dichroic prism 14
Either the attenuation rate corresponding to the demultiplexing rate of 1 or the attenuation rate of 1/1 and the set output value are input to the laser control circuit 2. The laser control circuit 2 calculates the required oscillation output from these input values, compares it with the signal from the amplifier 12, and compares it with the laser oscillator 1
Feedback control.

Next, the operation of this device will be described. In the device of the present invention configured as described above, the mode discriminating circuit 18 causes the output value set by the output setting device 16 to be a low output setting value or a high output setting depending on the demultiplexing ratio of the dichroic prism 14. The value is determined. When the normal oscillation output of the laser oscillator 1 is 100 W, for example, the multilayer film coat 1 of the dichroic prism 14 is used.
In order to demultiplex the laser light 3 so that the laser light 3 becomes 10% on the condenser lens system 4 side and 90% on the condenser lens 19 side, the mode discrimination circuit 18 sets the set output value of 10 W or less to a low level. The output (that is, used in contact irradiation therapy) and the set output of 10 to 100 W are determined to be high output (that is, used in non-contact therapy), and a determination signal indicating this is output. In the case where the condenser lens system 4 is divided into 20% and the condenser lens 19 is divided into 80%, the mode discrimination circuit 18 outputs 20 W.
The following setting output is discriminated as a low output and a setting output of 20 to 100 W is discriminated as a high output, and a discrimination signal is outputted.

When the output value set by the output setting device 16 is judged to be low output by the mode judging circuit 18, the mode judging circuit 18 supplies electric power to the solenoid 15 to drive it, thereby driving the dichroic prism 14 to the laser. Advance to the optical path of light 3. At the same time, the attenuation rate setting circuit 25 uses the signal from the mode discrimination circuit 18 to determine the attenuation rate according to the demultiplexing rate of the dichroic prism 14 (1/10 in the former case, 1/5 in the latter case). Is set. Then, the set output value is input to the laser control circuit 2 together with the attenuation rate.

The laser control circuit 2 controls the oscillation output of the laser oscillator 1 by a value obtained by dividing the set output value by the attenuation rate, and by pressing a foot switch (not shown), for example, when the output set value is 2 W and the attenuation rate is 1 / In case of 10, oscillation output 20W,
If the attenuation rate is 1/5, laser light with an oscillation output of 10 W 3
Oscillates. Then, a laser beam of 2 W, which is the same as the set output value, of the laser beam 3 passes through the monitor prism 9 and enters the condenser lens system 4, and the incident end face 5 a of the fiber 5
And is emitted from the tip of the sapphire chip 6 on the emission end face 5b. However, in the above numerical example, the losses in the condenser lens system 4 and the fiber 5 are neglected for simplification of description.

According to the present invention, as can be seen from this description, the laser light emitted from the tip of the sapphire chip 6 is not pulse-modulated output but continuous output, and is emitted at the same output as the set output value. It Therefore, it is possible to ensure the safety such that the sapphire chip 6 is not cracked or the irradiation site is not perforated.

On the other hand, the remaining laser light demultiplexed by the dichroic prism 14 enters the condenser lens 19, enters the inside of the absorber 21 through the minute aperture 23, and is absorbed by the absorber 21. It is preferable to apply a black heat-resistant coating material, an absorbing material 24 such as carbon graphite, to the entire inner circumference of the absorber 21, and the laser light is repeatedly attenuated a number of times to be attenuated sequentially, and almost all of the laser light is attenuated. Energy is absorbed. Therefore, it is preferable to increase the heat capacity of the absorber 21 or to cool the outer wall of the absorber 21 via a suitable cooling medium. By doing so, not only does the stability of the laser oscillator 1 decrease and the malfunction of the laser oscillator 1 is not caused by the heat of the absorbed laser light, but also the structure is such that the laser light is confined in the absorber 21. Damage to the laser oscillator 1 or part of the power source due to reflected or scattered laser light, or the laser light leaking to the outside and inadvertently damaging the skin or eyes of the operator, assistant, nurse, etc. Sufficient safety can be secured so that there is no

Next, when the output value set by the output setting device 16 is high, the mode discriminating circuit 18 stops the power supply to the solenoid 15 and retreats the dichroic prism 14 from the optical path of the laser beam 3. Let The signal from the mode discrimination circuit 18 causes the attenuation rate setting circuit 25 to receive 1 /
The attenuation rate of 1 is set, and this attenuation rate and the set output value are input to the laser control circuit 2. And laser control circuit 2
Is a value obtained by dividing the set output value by the attenuation rate, that is, in this case, by controlling the oscillation output of the laser oscillator 1 to the same value as the set output value, and pressing a foot switch (not shown) The light is transmitted through the monitor prism 9 without being demultiplexed, is incident on the condenser lens system 4, is condensed on the incident end face 5a of the laser fiber 5, and is emitted from the emission end 5b.

Incidentally, the laser light reflected very slightly due to the difference in refractive index between the right-angled prism 8 of the monitor prism 9 and the optical adhesive 7 enters the light receiving surface of the output detector 11 after passing through the filter 10. The output of the output detector 11 is amplified by the amplifier 12 and then input to the laser control circuit 2 to feedback control the laser oscillation output during the laser oscillation.

[0031]

As described above, the output attenuator of the laser treatment apparatus according to the present invention is not a pulse-modulated output of the resulting laser beam but a continuous output, and the output is the same as the set output value. Is emitted, there is no risk of cracks in the sapphire chip of the laser fiber or the risk of perforation at the irradiation site during contact irradiation therapy, and sufficient safety for the patient can be ensured. ..

Further, almost all of the energy of the laser light demultiplexed by the dichroic prism as the demultiplexer is absorbed in the absorber, so that the stability of the laser oscillator is deteriorated and a malfunction occurs. Not only does it not occur, but because the laser light is confined inside the absorber, it has an excellent effect of not leaking the laser light to the outside and damaging the skin or eyes of the operator, assistant, nurse, etc. Have.

[Brief description of drawings]

FIG. 1 is a diagram showing, together with a block diagram, an apparatus according to an embodiment of the present invention, showing a state in which a spectroscopic unit is advanced on an optical path of laser light.

FIG. 2 is a diagram showing, together with a block diagram, a state in which a spectroscopic unit is withdrawn from the optical path of laser light in the apparatus of FIG.

[Explanation of symbols]

 3 Laser Light 4 Condensing Lens System 5 Laser Fiber 5a Incident End 5b Output End 6 Sapphire Chip 7 Optical Adhesive 8 Right Angle Prism 9 Output Monitor / Prism 10 Filter 13 Multilayer Coating 14 Dichroic Prism 19 Condensing Lens 20 Plane 21 Absorber 23 Micro aperture 24 Absorber

Claims (5)

[Claims] 1. A laser treatment apparatus for guiding laser light oscillated by a laser oscillator to a diseased part through a laser fiber for treatment, and a laser control circuit for controlling oscillation output of the laser oscillator, and a laser light transmission optical path of the laser oscillator. And a demultiplexing unit that demultiplexes the laser beam at a predetermined ratio, and the laser beam demultiplexed by the demultiplexing unit enters an internal space through an opening, and the laser beam is formed on the inner surface of the internal space. An output attenuating device for a laser treatment device comprising a laser light absorbing means for absorbing light. 2. The laser treatment according to claim 1, wherein the absorption device includes an absorber having a minute aperture, and a condenser lens for condensing the laser light demultiplexed from the demultiplexing means onto the minute aperture. Equipment output attenuator. 3. The hollow absorbent body is provided with a flat surface portion on a part of a spherical inner surface, and a minute opening is provided at a position apart from a spherical center of the flat surface portion. The output attenuation device of the laser treatment apparatus according to 2. 4. The output attenuating device of the laser treatment apparatus according to claim 3, wherein a laser light absorbing material is applied to an inner surface of the absorber. 5. The output attenuating device of the laser treatment apparatus according to claim 1, wherein the demultiplexing means is a dichroic prism.