JPS61185261A - Apparatus for detecting breakage of laser fiber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention: a. Technical Field The present invention relates to a detection device for detecting combustion caused by leakage of high-power laser light due to breakage of power transmission fiber in processing and medical laser devices. It is related to.

b. Prior art and its problems Generally, the length of the power transmission fiber used in medical laser scalpels, etc. is several meters, and the entire length of the fiber is visible, so the fiber may be damaged and the high-power laser beam Even if a situation were to occur, such as leakage to the outside of the core, it could be easily detected. However, in cases where the fiber length is several tens of meters and is routed through the walls or ceiling of a building, the middle part of the fiber may be damaged and high-power laser light may leak to the outside of the core. Even if the covering member etc. burns, it is difficult to detect it, so there is a possibility that the laser beam will continue to be irradiated, which is a safety problem. Conventionally, in order to detect damage to a fiber, a method is disclosed in Japanese Utility Model Application Publication No. 54-120883, in which a conductive wire is wound around the fiber and bending of the fiber is detected by checking whether the conductive wire is conductive or non-conductive. Furthermore, a fiber cut detection device has already been proposed, which consists of a light guiding fiber wound around a fiber and a photodetector attached to the end of the fiber. However, in the former case, even if the fiber is not damaged and only the conductor is damaged, it is treated as a broken fiber, and it is difficult to distinguish whether the fiber is simply broken or the fiber is burnt. In the latter case, after one end of the fiber is damaged and the light guide fiber is cut, the fiber breakage cannot be detected before high-power laser irradiation in the next use.

C0 Purpose The present invention has been made in view of the above points, and provides a detection device that easily detects fiber burning caused by fiber bending and fiber bending before high-power laser irradiation. aim at something.

d. Configuration of Embodiment An embodiment of the present invention will be described below based on the drawings. Reference numeral 1 denotes an oscillator that oscillates a high-power laser beam, and the laser beam 2 oscillated from the oscillator is focused by a lens 3 and enters into one end of a power transmission fiber 4. The power transmission fiber 4 is installed through a wall of a building or the like from a laser generating section to a place where processing or treatment is performed using laser light. A light guide fiber 5 is arranged adjacent to the power transmission fiber 4, and a light emitting element 6 such as an LED or an LD is arranged at one end of the light guide fiber 5. It is connected to the pulse modulation circuit 7. Further, a light receiving element 8 such as a Hole diode is disposed at the other end of the light guiding fiber 5,
The light receiving element 8 is connected to a signal processing circuit 9, and a signal line is connected from the signal processing circuit 9 to the laser oscillator 1.

It is preferable that the light guiding fiber 5 be a thermoplastic plastic fiber in order to detect bending or the like in the power transmitting fiber 4.

e. Effects of the Examples Next, the effects of the present invention will be explained. Pulse modulation circuit 7
Accordingly, the optical signal shown in FIG. 2a is emitted from the light emitting element 6, passes through the light guide fiber 5, and then enters the light receiving element 8, becoming the output signal shown in FIG.
is input to. If the power transmission fiber 4 is broken in the middle for some reason, the high-power laser beam 2 leaks out and is absorbed by the fiber coating member and burned.

The light guide fiber 5 is cut by this combustion and the leaked high-power laser, and instead of the signal shown in the normal state, a signal C due to the combustion is transmitted from the light receiving element 8 to the signal processing circuit 9.
is input to. As the input changes from b to C, the signal processing circuit 9 outputs an oscillation stop signal to the laser oscillator l to stop the oscillation of the high-power laser. In addition, if the power transmission fiber 4 is broken before high-power laser irradiation, and the light guide fiber is physically broken as well, the signal level will be almost zero as shown by d instead of the normal signal. The signal is input to the signal processing circuit 9. Since the input is in the form d, the signal processing circuit 9 outputs an oscillation stop signal to the laser oscillator 1 to prevent the high-power laser from being oscillated.

f. Effects As shown in F-F, according to the implementation of the present invention, if high-power laser light leaks out of the fiber and affects piping members or other buildings, it will be detected and the laser will be activated. It is possible to stop the oscillation and prevent the occurrence of fire, etc. In addition, damaged fibers are detected before high-power laser oscillation,
It is possible to prevent the thermal influence of the laser beam from spreading to other members. In this way, when laser light is guided through fiber over long distances in medical and industrial applications, it is possible to prevent accidents such as fires due to damage to invisible parts of the fiber, which has a great safety effect. There is something.

[Brief Description of the Drawings] Fig. 1 is an overall view showing one embodiment of the present invention, and Fig. 2 is a general view showing an embodiment of the present invention.
It is a figure which shows the example of a detection signal. 1: Laser oscillator a: Emission signal 2: Laser light b: Normal light reception signal 3: Lens C: Light reception signal when fiber is burned 4: Power transmission fiber d: Light reception signal when fiber is cut 5
: Light-guiding fiber 6: Light-emitting element 7: Pulse modulation circuit 8: Light-receiving element 9: Signal processing circuit Patent applicant: Asahi Optical Co., Ltd. Representative: Retired Matsumoto

Claims (1)

[Scope of Claims] 1. A light guide fiber wired adjacent to a high-power laser transmission fiber, a light emitting element installed at one end of the light guide fiber and connected to a pulse modulation circuit; A laser fiber break detection device comprising a light receiving element installed at the other end of a light guiding fiber and a signal processing circuit connected to the light receiving element. 2. The fiber breakage detection device according to claim 1, wherein the light guiding fiber is made of a thermoplastic plastic fiber.