JPH0360267B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an output attenuation device for attenuating laser light oscillated by a laser oscillator in a laser treatment device such as a laser scalpel or a laser coagulator.

[Prior Art] Laser treatment devices that utilize the energy of laser light include laser scalpels and laser coagulators. For example, laser scalpels treat living tissue using YAG laser light or CO ₂ laser light, as is well known. This device performs incision, coagulation, and hemostasis on affected areas such as polyps and ulcers, and performs incision and vaporization treatment for affected areas such as polyps and ulcers. It consists of a light guide section that guides the light up to.

Recently, in this laser scalpel, a transparent sapphire tip is connected to the output end of the lightweight and highly flexible laser fiber, and the tip of this sapphire tip is brought into contact with the affected area under observation with an endoscope.
Contact irradiation therapy, in which laser light is irradiated to coagulate and incise the affected tissue, has been put into practical use.

In this type of contact irradiation therapy, the irradiation energy density of the YAG laser light is much higher than in conventional non-contact therapy, and reflection and scattering on the surface tissue of the affected area is suppressed, so even low output power can be used. A sufficient therapeutic effect can be expected.
For example, when aiming for coagulation, specific contact therapy requires an output of 30W or more, while contact radiation therapy requires an output of 6W or less, about 1/5 of that, which is equivalent to non-contact therapy. effect can be obtained.

On the other hand, when using this YAG laser light for non-contact therapy aimed at hemostasis, a high output of about 100W is required. However, the conventional output of 100W
In this class of YAG laser treatment devices, the population inversion threshold for starting laser oscillation corresponds to an output of nearly 10W, so it is not possible to stably oscillate at a low output of 10W or less. That is, even if the current of the laser excitation lamp is controlled so that the output is low, there is a problem in that either laser oscillation does not occur, or even if it does oscillate, the output is extremely unstable.

Conventionally, the first method to solve these problems was to use two YAG machines, a high-output type and a low-output type.
Laser treatment equipment was prepared in the operating room, and the treatment equipment was used depending on the content of the treatment.

In addition, as a second method, a light shielding device is built in, in which a light-transmitting part and a light-blocking part are alternately provided at an appropriate ratio around the rotating disk, and the light shielding device is made to move forward and backward in the laser beam path. A laser treatment device has been proposed in which most of the YAG laser light is blocked by a chopper and only a portion of it is allowed to pass through in order to obtain a low output.

[Problems to be Solved by the Invention] In the above-mentioned first conventional method, the installation floor space is large, which limits the degree of freedom for the surgeon, assistant, nurse, etc. With the complexity of having to use different treatment devices accurately,
Overall, it had the disadvantage of being expensive. In addition, in the second method, although the apparent average output is low, the split pulsed laser beam itself has extremely high output and high energy density, so the output end of the laser fiber It has the disadvantage that it may cause cracks in the connected sapphire chip and there is a risk of perforation in the irradiated area. Moreover, since most of the continuous wave high-power YAG laser light of about 100W is blocked by the chopper, the YAG laser beam absorbed by the light-shielding part of the chopper
The chopper part is heated by the laser beam, and as a result, not only does the chopper malfunction, but the generated heat reduces the stability of the laser oscillator, and the light shielding part of the chopper or the edge between the light shielding part and the transparent part The reflected and scattered YAG laser light may damage part of the laser oscillator and power supply, or the reflected and scattered YAG laser light may leak outside the laser treatment device, causing damage to the skin of the surgeon, assistant, nurse, etc. It had a major practical drawback of inadvertently causing damage to the eyes.

The present invention was made to solve these problems, and uses a single laser oscillator to
It is an object of the present invention to provide an output attenuation device so that both high-power and low-power therapeutic laser beams can be obtained.

A second object of the present invention is to provide an output attenuation device that has a continuous oscillation type rather than a pulse type and can set the output power to a desired value.

A third object of the present invention is to provide an output attenuation device that does not cause any damage to the skin or eyes of surgeons, assistants, nurses, etc. due to reflection, scattering, etc.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a component that is optically demultiplexed at a predetermined ratio in the optical path of the laser light emitted from the laser oscillator. The wave means was arranged so that it could move forward and backward. The laser beam split by the splitting means, such as a dichroic prism, is completely absorbed by the absorber using a condensing lens. The absorber is preferably a hollow body with a spherical inner surface, and the laser beam from the condensing lens enters the absorber through its microscopic aperture.
Absorbed.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIGS. 1 and 2 are configuration diagrams showing an embodiment of the output attenuation device of the present invention. FIG. 1 shows the case where it is used for contact radiation therapy, and FIG. 2 shows the case where it is used for non-contact therapy. . In the figure, reference numeral 1 is a laser oscillator, and this laser oscillator 1 is connected to a laser control circuit 2.
The laser beam 3 is activated by receiving power from the laser beam 3 and oscillates the laser beam 3. When performing contact irradiation therapy, this laser beam 3 is transmitted to a condensing lens system 4 as shown in FIG.
The light is focused on the input end face 5a of the laser fiber 5 through the laser fiber 5, and is emitted from the tip of the sapphire chip 6 connected to the output end face 5b. On the other hand, in the case of normal non-contact therapy, laser light is emitted from the emission end face 5b of the laser fiber 5, as shown in FIG.

In the optical path between the laser oscillator 1 and the condensing lens system 4, an output monitoring prism 9, which is made by bonding two right-angled prisms 8 together with an optical adhesive 7, is disposed. Due to the difference in refractive index between the optical adhesive 7 and the right angle prism 8, a very small amount of laser light is reflected.
The light passes through the filter 10 and enters the light receiving surface of the output detector 11 . The filter 10 has a characteristic of selectively passing only a necessary wavelength band. After the output of the output detector 11 is amplified by the amplifier 12,
It is input to the laser control circuit 2.

In addition, a guide light (usually He-Ne
A dichroic prism 14 coated with a multilayer film 13 is arranged so that almost 100% of the laser beam (not shown) is transmitted therethrough and the laser beam 3 emitted from the laser oscillator 1 is split at a predetermined ratio. It has been set up. This dichroic prism 14 is
By driving the solenoid 15, it can be moved freely from the optical path to outside the optical path and from outside the optical path to the optical path.

The output setting device 16 is a device for setting a laser output value desired by the operator as a laser treatment device,
The display device 17 displays the set output value. The output value set by the output setting device 16 is sent to the mode discrimination circuit 18. The mode discrimination circuit 18 compares the threshold value determined according to the division factor of the dichroic prism 14 with the set output value from the output force setting device 16, and
This circuit determines whether or not to interpose the laser beam 3 on the optical path of the laser beam 3. That is, the mode discrimination circuit 18
It is also a circuit that determines whether the laser treatment device is used for non-contact therapy or contact irradiation therapy based on the set output value of the output setting device 16. The mode discrimination circuit 18 drives the solenoid 15 when the set output value is lower than the threshold value, and the dichroic
The prism 14 is advanced onto the optical path of the laser beam 3.

The laser beam split by the prism 14 is focused by the condensing lens 19 onto the minute aperture 23 of the hollow absorber 21, which has a spherical inner surface with a partially flat portion 20. Almost all of the energy is absorbed within the absorber 21 as it is reflected many times. Micro opening 23
is opened at a position away from the center of the flat portion 20 so that the laser beam incident thereon is reflected many times inside. Note that the entire inner circumference of the absorber 21 is coated with an absorbing material 24 that absorbs laser light.

The discrimination signal from the mode discrimination circuit 18 is input to the attenuation rate setting circuit 25. attenuation rate setting circuit 25,
Depending on this discrimination signal, either the attenuation rate corresponding to the splitting factor of the dichroic prism 14 or the attenuation rate of 1/1 and a set output value are input to the laser control circuit 2. The laser control circuit 2 calculates the necessary oscillation output from these input values, compares it with the signal from the amplifier 12, and performs feedback control of the laser oscillator 1.

Next, the operation of this device will be explained. In the device of the present invention configured as described above, the mode discrimination circuit 18 determines whether the output value set by the output setting device 16 is a low output setting value or a high output value, depending on the demultiplexing factor of the dichroic prism 14. Determine which of the set values it is. The normal oscillation output of the laser oscillator 1 is assumed to be 100W. For example, the multilayer coating 13 of the dichroic prism 14 directs 10% of the laser beam 3 to the condensing lens system 4 side and 90% to the condensing lens 19 side.
%, the mode discrimination circuit 18 selects a set output value of 10W or less as low output (i.e., used in contact radiation therapy), and a set output value of 10 to 100W as high output (i.e., non-contact radiation therapy). (used in contact therapy),
A discrimination signal representing this is output. In addition, if the configuration is such that 20% is split into the collective lens system 4 side and 80% is split into the condensing lens 19 side, the mode discrimination circuit 18 selects a set output of 20W or less as a low output, and a set output of 20W or less.
It discriminates the set output of 100W as high output and outputs a discrimination signal.

When the output value set by the output setting device 16 is determined to be low output by the mode determination circuit 18,
The mode discrimination circuit 18 supplies power to the solenoid 15 to drive it, and causes the dichroic prism 14 to advance onto the optical path of the laser beam 3. At the same time, the attenuation rate setting circuit 25 receives a signal from the mode discrimination circuit 18 to set an attenuation rate corresponding to the demultiplexing factor of the dichroic prism 14 (1/10 in the former case, 1/5 in the latter case). ) is set. The set output value is then input to the laser control circuit 2 together with this attenuation rate. The laser control circuit 2 controls the oscillation output of the laser oscillator 1 by the 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 2W and the attenuation rate is 1/10, When the oscillation output is 20W, and the attenuation rate is 1/5, the laser beam 3 with an oscillation output of 10W is oscillated. Of this laser beam 3, a laser beam of 2 W, which is the same as the set output value, passes through the monitor prism 9 and enters the condensing lens system 4, and is condensed onto the input end surface 5a of the fiber 5, and is focused on the output end surface 5b. The light is emitted from the tip of the Saffire chip 6. However, in this numerical example, for the sake of simplicity, losses in the collective lens system 4, fiber 5, etc. are ignored.

In the present invention, as can be seen from this explanation, the laser light emitted from the tip of the Saffire chip 6 is not a pulse-modulated output but a continuous output, and moreover, it is emitted with the same output as the set output value. Therefore, safety can be ensured so that there is no risk of cracking the sapphire chip 6 or perforation of the irradiation site.

On the other hand, the remaining laser beam split by the dichroic prism 14 enters the condenser lens 19,
It enters the inside of the absorber 21 through the minute opening 23 and is absorbed by the absorber 21 . The entire inner periphery of the absorber 21 is covered with an absorbent material 2 such as black heat-resistant paint or carbon graphite.
4 is preferable, and the laser beam is reflected many times here and is sequentially attenuated, so that almost all of its energy is absorbed. Therefore, either the heat capacity of the absorber 21 is increased or the absorber 2
Preferably, the outer wall of 1 is cooled via a suitable cooling medium. By doing this, not only will the stability of the laser oscillator 1 not be reduced or malfunction occur due to the heat of the absorbed laser light, but also the structure is such that the laser light can be confined within the absorber 21. , part of the laser oscillator 1 or power supply may be damaged due to reflected or scattered laser light, or
Alternatively, sufficient safety can be ensured so that the laser light does not leak to the outside and inadvertently damage the skin or eyes of the surgeon, assistant, nurse, etc.

Next, when the output value set by the output setting device 16 is a high output, the mode discrimination circuit 18 stops supplying the output to the solenoid 15 and
The prism 14 is removed from the optical path of the laser beam 3. An attenuation rate of 1/1 is set in the attenuation rate setting circuit 25 by the signal from the mode discrimination circuit 18, and this attenuation rate and the set output value are input to the laser control circuit 2. Then, the laser control circuit 2 controls the oscillation output of the laser oscillator 1 to a value obtained by dividing the set output value by the attenuation rate, that is, in this case, the same value as the set output value, and presses a foot switch (not shown) to generate the oscillated laser. The light 3 passes through the monitor prism 9 without being demultiplexed, enters the condenser lens system 4, is condensed onto the input end face 5a of the laser fiber 5, and is emitted from the output end 5b.

Note that the laser beam that is reflected slightly due to the difference in refractive index between the right angle prism 8 of the monitor prism 9 and the optical adhesive 7 passes through the filter 10 and then enters the light receiving surface of the output detector 11. The output of is amplified by an amplifier 12 and then sent to a laser control circuit 2.
The laser oscillation output is fed back and controlled while the laser oscillation is being performed.

[Effects of the Invention] As described above, the output attenuation device of the laser treatment device of the present invention is such that the resulting laser light is not a pulse-modulated output but a continuous output, and moreover, the output is the same as the set output value. is emitted, so
When performing contact irradiation therapy, there is no risk of cracks in the sapphire tip of the laser fiber or perforation of the irradiated area, and sufficient safety for the affected area can be ensured.

Furthermore, almost all of the energy of the laser beam split by the dichroic prism that serves as a splitter is absorbed within the absorber, so it will not reduce the stability of the laser oscillator or cause malfunction. Furthermore, since the laser light is confined within the absorber, it has excellent effects such as no damage to the skin or eyes of the surgeon, assistant, nurse, etc. due to the laser light leaking outside.

[Brief explanation of drawings]

1 and 2 are block diagrams showing one embodiment of the present invention. 3... Laser light, 4... Condensing lens system, 5...
Laser fiber, 5a...Incidence end, 5b...Output end, 6...Sapphire chip, 7...Optical adhesive, 8...Right angle prism, 9...Output monitor prism, 10...Filter, 13...Multilayer Membrane coat, 14... Dichroic prism, 19
... Condensing lens, 20 ... Plane part, 21 ... Absorber, 23 ... Micro aperture, 24 ... Absorber.

Claims (1)

[Scope of Claims] 1. A laser treatment device that guides a laser beam oscillated by a laser oscillator to an affected area via a laser fiber for treatment, which is capable of moving forward and backward into the laser beam transmission optical path of the laser oscillator, and transmits the laser beam at a predetermined rate. Determines the output value set by the demultiplexing means and the output setting device according to the demultiplexing ratio of the demultiplexing means, and determines whether to enter the optical path of the laser beam into the demultiplexing means or to evacuate from there. a mode discriminating circuit for instructing; an attenuation rate setting circuit for setting an attenuation rate according to a branching factor of the demultiplexing means based on a discrimination signal from the mode discriminating circuit;
Consisting of a laser control circuit that controls the oscillation output of the laser oscillator by a value obtained by dividing the output setting value by the attenuation rate from the attenuation rate setting circuit, and an absorption device that absorbs the laser light split by the splitting means. An output attenuation device for a laser treatment device, characterized in that: 2. The laser according to claim 1, wherein the absorption device comprises an absorber having a microscopic aperture, and a condenser lens that focuses the laser beam split from the splitting means onto the microscopic aperture. Output attenuation device for therapy equipment. 3. Claim 2, wherein the hollow absorbent body has a flat part on a part of the spherical inner surface, and a minute opening is provided at a position away from the spherical center of the flat part. The output attenuation device of the laser treatment device described in 2. 4. The output attenuation device for a laser treatment device according to claim 3, wherein the inner surface of the absorber is coated with a laser light absorbing material. 5. The output attenuation device for a laser treatment apparatus according to any one of claims 1 to 4, wherein the demultiplexing means is a dichroic prism.