JPH0459575B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a safety device for detecting trouble in a laser power transmission fiber.

b. Conventional technology Trouble detection safety that detects breaks in optical fibers (hereinafter referred to as fibers) that transmit high-power laser light used in conventional medical laser devices, etc., and damage to the input end face and output end face of the fibers. The device detected trouble based on changes in the amount of light reflected from the output end face of the fiber.

c Problems to be Solved by the Invention However, such conventional trouble detection safety devices do not work well with fibers, such as laser irradiation when the bladder is filled with saline in the treatment of bladder tumors. When using the fiber with its output end immersed in water, the reflectance of the fiber's output end decreases dramatically, resulting in the fiber being detected as being in trouble even though it is in a normal condition. There was an inconvenience that the laser could not be irradiated.

The present invention has been made in view of the above-mentioned problems, and has been developed to provide a trouble detection safety device for power lasers for general use in endoscopic treatment and surgical treatment in gastroenterology and respiratory departments. This allows the power laser to be used without any inconvenience not only when using the power laser in the atmosphere, but also when using the power laser underwater, such as in the treatment of bladder tumors in the urological field, such as cauterization. In other words, if the tip of the fiber is damaged or broken, it is immediately detected and connected to the safety mechanism, and even when laser irradiation is performed underwater, such as in the treatment of bladder tumors, appropriate treatment can be carried out. The purpose is to provide a fiber trouble detection safety device that can be used.

d Means for Solving the Problems In order to achieve the above object, the safety device for detecting trouble in a transmission fiber according to the present invention includes a laser light source that emits a power laser beam and a hollow pipe. The inserted transmission fiber, an optical system that focuses the power laser beam emitted from the laser light source onto the input end face of the transmission fiber, and a supply that supplies air from the gap between the pipe and the transmission fiber. a light receiving means for detecting light emitted from the input end of the transmission fiber; and a light receiving means disposed on the input side of the light receiving means and emitted from the input end surface of the transmission fiber. a first comparator that compares the output of the light receiving means with a predetermined first reference value; and a first comparator that compares the output of the light receiving means with a predetermined second reference value. a second comparator for comparing the output of the first comparator with a reference value; and gate means for passing the output of the first comparator when the air supply mechanism is driven and blocking it when the air supply mechanism is stopped;
and means for stopping the power laser beam from entering the transmission fiber when either the second comparator or the output of the gate means is output, the second invention. A laser light source that emits a power laser beam, a transmission fiber inserted into a hollow pipe, and an optical system that focuses the power laser beam emitted from the laser light source onto an incident end face of the transmission fiber. , a laser device comprising an air supply mechanism that supplies air from a gap between the pipe and the transmission fiber, wherein first and second laser beams detect light emitted from the input end of the transmission fiber;
of the light receiving means disposed on the incident side of these light receiving means and emitted from the incident end face of the transmission fiber, the reflected light of the power laser is made to enter the first light receiving means and the transmission fiber is arranged on the incident side of the light receiving means. As for the secondary light generated by combustion in the damaged part of the fiber, there is a selection means for making the secondary light enter the second light receiving means, and a second light receiving means for comparing the output of the first light receiving means with a predetermined first reference value. 1 comparator, the output of the second light receiving means and a predetermined second
a second comparison value for comparing with a reference value of
gate means for passing the output of the comparator when the air supply mechanism is driven and blocking it when the air supply mechanism is stopped; The present invention is characterized by comprising means for stopping the light from entering the transmission fiber.

e. Configuration of Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention,
First of all, to explain the irradiation mechanism of power laser beam 2, code 1 is Nd:YAG laser,
A laser light source such as a Co laser, and a power laser beam 2 emitted from the laser light source 1
passes through the shutter mechanism 3 interposed in the optical path,
The light passes through the transmission mirror 4 and is focused on the incident end face of the fiber 6 by the condenser lens 5,
The radiation passes through the fiber 6 and irradiates the affected area from the output end of the fiber 6.

Next, the trouble detection safety mechanism of the fiber 6 will be explained. The complete trouble detection mechanism of the fiber 6 explained in this embodiment consists of the power laser reflected light 7a and the secondary light emitted from the input end of the fiber 6. 7b is detected, trouble in the fiber 6 is discovered, and a safety mechanism is activated. In other words, even in a normal fiber, the power laser beam 2 will affect a certain percentage of the fiber 6.
If the output end of the fiber 6 is damaged or the input end of the fiber 6 is deviated from the optical axis of the lens 5, Since the power laser reflected light 7a that is reversely transmitted to the input end is attenuated, troubles in the fiber 6 can be discovered by detecting this change. Also,
When the fiber 6 is broken in the middle or the output end face or the input end face of the fiber 6 is damaged, the secondary light is generated when the power laser beam 2 is passed through the fiber 6 and the power laser beam 2 is generated at the defective point.
Scattering and reflection of the fiber 6 occurs, which causes the cladding and polymer coating material of the fiber 6 at the defective location to burn, emitting light. Trouble in the fiber 6 can also be discovered by detecting light. The trouble detection safety mechanism to be described below operates the safety mechanism by detecting the power laser reflected light 7a and the secondary light 7b.

Now, the above-mentioned trouble has occurred, and the power laser reflected light 7a is reflected from the incident light of the fiber 6.
When the power laser reflected light 7a and the secondary light 7b are emitted, the emitted power laser reflected light 7a and the secondary light 7b pass through the condenser lens 5, and a few percent of them are collected by the transmission mirror 4. (Even a transmissive mirror always reflects some percent of the incident light.) A filter 8 for balancing the power laser reflected light 7a and the secondary light 7b (in this embodiment, the power laser (A partial absorption filter is used to reduce the invisible light component of the reflected light 7a.) The light is received by a detector 9 as a light receiving means such as a phototransistor or a photodiode.

The detector 9 converts the power laser reflected light 7a and the secondary light 7b into electrical signals. The electrical signals of the power laser reflected light 7a and the secondary light 7b are amplified by an amplifier 10, and resistors 11a and 11b are used to detect changes in the power laser reflected light 7a.
It is input to one input terminal of the first comparator 12 with a voltage division ratio of entered at the end.

At the other input terminals of the first and second comparators 12 and 19, a reference voltage level A (see FIG. 3) of the reflected light 7a from the output end face of the power laser beam 2 passing through the normal fiber is generated. Reference circuit 20
is connected. Further, the first comparator 12
The output terminal of is an AND (logical product) as a gate means.
The circuit 13 is connected to one input terminal, and the pump drive circuit 14 is connected to the other input terminal of the AND (logical product) circuit 13.
Operation of the air pump 15 by ON/OFF operation,
Deactivation is controlled.

The air pump 15 is used to send air or the like from the gap between the fiber 6 and the protective pipe 17 of the fiber 6 to the output end of the fiber 6 via the air pipe 16, and prevents air from scattering from the affected area during laser irradiation. To prevent dirt from adhering to the output end of the fiber 6.

Incidentally, reference numeral 18 is a gasket fitted into one end of the protection pipe 17 to prevent air leakage.

Furthermore, the output terminal of the AND (logical product) circuit 13 is connected to one input terminal of an OR (logical sum) circuit 21, and the other input terminal of the OR (logical sum) circuit 21 is connected to the second The output end of the comparator 19 is connected, and the output end of the OR (logical sum) circuit 21 is connected to a shutter drive circuit 22 as means for stopping the power laser beam from entering the fiber. The shutter drive circuit 22 is activated by a signal from the OR (logical sum) circuit 21, and closes the shutter mechanism 3 of the power laser beam 2 irradiation mechanism.

Next, the operation of the present invention will be explained.

Now, if we irradiate the power laser beam 2 without knowing that the fiber 6 is broken in the middle,
At the broken point, the power laser beam 2 is scattered and reflected, and the resin cladding and polymer coating material constituting the fiber 6 burns, resulting in secondary light 7b.
occurs.

Further, when the power laser beam 2 is irradiated, if the output end of the fiber 6 comes into contact with or is abnormally close to the irradiation site, the output end will be heated due to its high temperature, and the secondary light 7b will also be generated. Such secondary light 7b
is emitted from the input end of the fiber 6, passes through the lens 5, is reflected by the mirror 4, passes through the filter 8, and is received by the detector 9.

The secondary light 7b received by the detector 9 is converted into an electrical signal (along with the power laser reflected light 7a), amplified by the amplifier 10, and subjected to a second comparison using the partial pressure ratio of the resistor 11c and the resistor 11d. The signal is input to one input terminal of the device 19. Since the reference voltage level A is input from the reference circuit 20 to the other input terminal of the second comparator 19, the voltage-divided secondary light 7b
The voltage of the secondary light 7b (including the voltage of the power laser reflected light 7a) is compared with the reference voltage level A, and the voltage of the secondary light 7b (including the voltage of the power laser reflected light 7a) is determined in advance. When the upper limit voltage level B (see Figure 3) is reached, the second
The electrical signal output from the output terminal of the comparator 19 is
The OR (logical sum) circuit 21 is input to one input end of the OR (logical sum) circuit 21, and regardless of whether the power laser reflected light 7a is normal or attenuated, the OR (logical sum) circuit 21 is activated and sent to the shutter drive circuit 22. An electrical signal is sent to activate the shutter drive circuit 22, close the shutter mechanism 3, and stop the power laser beam 2 from entering the fiber 6.

Next, if the core exposed from the output end of the fiber 6 is damaged or the input end of the fiber 6 is misaligned with the optical axis of the lens 5, the fiber 6
The power laser reflected light 7a reflected from the output end face and emitted from the input end is attenuated.

The power laser reflected light 7a is reversely emitted from the input end of the fiber 6, passes through the lens 5, is reflected by the mirror 4, passes through the filter 8, and is received by the detector 9. The power laser reflected light 7a received by the detector 9 is converted into an electric signal, amplified by an amplifier 10, and then transmitted to a resistor 11a and a resistor 11b.
is inputted to one input terminal of the first comparator 12 at a voltage division ratio of .

Since the reference voltage level A is input from the reference circuit 20 to the other input terminal of the first comparator 12, the voltage-divided power laser reflected light 7a
The voltage of the power laser reflected light 7a is compared with the reference voltage level A, and when the voltage of the power laser reflected light 7a reaches a predetermined lower limit voltage level C (see FIG. 3), the output terminal of the first comparator 12 is electrical signal from
It is input to one input end of the AND (logical product) circuit 13, but normally when the power laser beam 2 is irradiated, it prevents dirt scattered from the affected area from adhering to the output end of the fiber 6. Since the drive circuit 14 of the air pump 15 is in the ON state, the electric signal from the drive circuit is also connected to the AND (logical product) circuit 13.
is input to the other input end of
The AND (logical product) circuit operates, and the output terminal of the AND (logical product) circuit 13 is connected to the OR (logical sum) circuit 2.
An electrical signal is input to the other input terminal of 1, and the OR
The (logical OR) circuit 21 is activated, sends an electric signal to the shutter drive circuit 22, activates the shutter drive circuit 22, closes the shutter mechanism 3, and blocks irradiation of the power laser beam 2.

Furthermore, when performing laser irradiation in a state where the bladder is filled with physiological saline, that is, underwater, such as in the treatment of a bladder tumor, a water supply mechanism may be used instead of an air supply mechanism using the air supply pump 15. When preventing contamination of the output end of the pump or cleaning the bleeding area, the pump drive circuit 14 is in an OFF state.
From the pump drive circuit 14 to the AND (logical product) circuit 13
No electrical signal is input to the other input terminal. Therefore, even though the fiber is irradiated with a laser underwater and is normal, the power laser reflected light 7a is attenuated due to the sharp decrease in the reflectance of the output end face of the fiber 6, and the AND (logical product) circuit 13 Even if the output signal from the first comparator 12 is sent to one input terminal of the Unless the output signal from the comparator 19 of 2 is input to the OR (logical sum) circuit 21, the OR (logical sum) circuit 21 will not operate, so even if the fiber 6 is in a normal state, the above power laser The inconvenience that laser irradiation cannot be performed due to the attenuation of the reflected light 7a is eliminated.

The reason why the balance filter 8 is provided on the optical path between the transmission mirror 4 and the detector 9 is as follows. That is, the amount of reflected light 7a from the fiber output end face of the power laser beam is much larger than the amount of secondary light 7b, which is combustion light. The change in the electrical signal due to 9 is
It depends exclusively on changes in the reflected light 7a. Therefore, for example, in a case where the reflected light 7a decreases, even if the secondary light 7b is generated, it may not appear as a change in the voltage of the electric signal from the detector 9. In such a case, the second comparator 19 will not be able to output an electrical signal for operating the OR circuit 21 (that is, an electrical signal for driving the shutter drive circuit 22). Therefore,
A filter was provided in advance to cut off the power laser beam as much as possible, so as to maintain a balance between the reflected light 7a and the secondary light 7b.

FIG. 2 shows another embodiment of the present invention, in which the power laser reflected light 7a and the secondary light 7b emitted from the input end of the fiber 6 are split by a mirror 23 as a selection means. As the mirror 23, a well-known dielectric multilayer filter such as a bandpass filter that passes only light of a specific wavelength or a band reflection filter that reflects only light of a specific wavelength can be used. Here, a filter that reflects light at the wavelength of the power laser light (for example, 1064 mm) and transmits other light may be used. Secondary light 24a branched by the mirror 23
is received by a second detector 9a as a second light receiving means, and the electrical signal of the secondary light 24a converted by the second detector 9a is amplified by an amplifier 10a, Further, the power laser beam 24b branched by the mirror 23 is received by a first detector 9b as a first light receiving means, and the first detector 9b
The electrical signal of the power laser beam 24b converted by is amplified by the amplification amplifier 10b. Note that since the power laser light is a single wavelength light, the mirror 23
However, since the secondary light is combustion light and has a continuous spectrum from the visible region to the infrared region, there is a possibility that a portion of the light is reflected by the mirror 23. However, by narrowing the wavelength range of the light reflected by the mirror 23, it is possible to sufficiently increase the transmittance of the secondary light. Further, the electrical signals of the secondary light 24a and the power laser light 24b, which have been independently amplified by the amplifiers 10a and 10b, are respectively independently amplified by the second and first comparators 19,
12 is input. Note that the other configurations and operations are the same as those of the embodiment shown in FIG. 1, so explanations thereof will be omitted.

In addition, in the above example, OR (logical sum)
Due to the operation of the circuit 21, the shutter drive circuit 22
was activated to close the shutter mechanism 3 to stop the power laser beam 2 from entering the fiber 6. However, due to the operation of the OR (logical sum) circuit 21, an electrical signal was sent to the laser light source 1 switch (not shown). of
It is also possible to adopt a configuration in which the laser light source 1 is inputted to a drive circuit to be turned off and the switch of the laser light source 1 is turned off.

f. Effects of the Invention The present invention is constructed as described above, and is capable of eliminating troubles such as breakage of fibers that transmit high-power laser beams used in medical laser devices, etc., and damage to the end faces of the fibers. In addition to instantaneous detection during irradiation to prevent accidents caused by power laser irradiation, it can also be used for treatment in the urological field, to prevent contamination of the fiber tip, and to use water to clean bleeding areas at the exit end of the fiber. Even when using the laser fiber immersed in water, it is possible to prevent false detection of a fiber trouble state.The device constructed according to the present invention has an extremely simple structure, so it can replace the entrance part of a conventional laser fiber. There is no need to change the width to a larger width, the manufacturing cost is lower, and safety can be ensured when used in medical laser equipment, making it extremely practical.

[Brief explanation of the drawing]

Fig. 1 is a partially block explanatory diagram showing one embodiment of the present invention, Fig. 2 is a partially block explanatory diagram showing another embodiment, and Fig. 3 is a reference voltage level A and an upper limit voltage. It is a graph diagram showing level B and voltage level C of the lower limit value. 1... Laser light source, 2... Power laser light, 3... Shutter mechanism, 6... Fiber,
7a... Power laser reflected light, 7b... Secondary light, 9... Detector.

Claims (1)

[Scope of Claims] 1. A laser light source that emits a power laser beam, a transmission fiber inserted into a hollow pipe, and a power laser beam emitted from the laser light source that is focused on an incident end face of the transmission fiber. and an air supply mechanism that supplies air from a gap between the pipe and the transmission fiber, a light receiving means for detecting light emitted from an input end of the transmission fiber;
a light attenuating means disposed on the incident side of the light receiving means to reduce an invisible light component of the light emitted from the incident end face of the transmission fiber; and a first reference value determined in advance as the output of the light receiving means. a second comparator that compares the output of the light receiving means with a predetermined second reference value, and a second comparator that compares the output of the first comparator with a predetermined second reference value; gate means for allowing the gate to pass through when the gate is stopped and blocking the gate when the gate is stopped;
and means for stopping the power laser beam from entering the transmission fiber when either the comparator or the output of the gate means is output. Safety device. 2. The light emitted from the input end of the transmission fiber includes the reflected light of the power laser beam from the output end face of the transmission fiber or the secondary light generated by combustion at a damaged part of the transmission fiber. A safety device for detecting trouble in a transmission fiber according to claim 1. 3. A laser light source that emits a power laser beam, a transmission fiber inserted into a hollow pipe, an optical system that focuses the power laser beam emitted from the laser light source onto an incident end surface of the transmission fiber, and the In a laser device comprising an air supply mechanism that supplies air from a gap between a pipe and the transmission fiber, first and second laser devices detect light emitted from an input end of the transmission fiber.
of the light receiving means disposed on the incident side of these light receiving means and emitted from the incident end face of the transmission fiber, the reflected light of the power laser is made to enter the first light receiving means and the transmission fiber is arranged on the incident side of the light receiving means. As for the secondary light generated by combustion in the damaged part of the fiber, there is a selection means for making the secondary light enter the second light receiving means, and a second light receiving means for comparing the output of the first light receiving means with a predetermined first reference value. 1 comparator, the output of the second light receiving means and a predetermined second
a second comparison value for comparing with a reference value of
gate means for passing the output of the comparator when the air supply mechanism is driven and blocking it when the air supply mechanism is stopped; 1. A safety device for detecting trouble in a transmission fiber, comprising means for stopping light from entering the transmission fiber.