JPS60210387A - Laser beam machining device - Google Patents

Abstract

PURPOSE:To enable sure monitoring of an optical fiber by detecting the light reflected from the inlet side end of an optical fiber which transmits laser light by a photodetector group and monitoring the condition of the optical fiber on the basis of the balance value calculated from the detected value. CONSTITUTION:The laser beam 15 emitted from a CO2 laser oscillating tube 14 is condensed by a condenser lens 16 and the laser beam made incident on the incident end 17a of the optical fiber 17 of a laser knife is emitted from an exit end 17b, then the laser beam condensed by a condenser lens 18 is conducted to a diseased part 19. The reflected light emitted from the incident end 17a is detected by the annular photodetector group 20 and the light energy received by respective photodetecting surfaces 21a, 21b, 21c is converted to electrical outputs. The condition of the fiber 17 is monitored in a central control part 27 from the result of the calculation by an arithmetic circuit 26 for balance. The execution of an abnormal disposition for the deterioration or damage of the optical fiber is thus made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a laser processing device that guides a laser beam through an optical fiber to a factory or nasal cavity to perform welding, cutting, incision of an affected area, evaporation, etc. It is related to.

Conventional configurations and their problems Laser processing devices or laser surgical devices that use YAG laser light or CO2 laser light use a plurality of reflecting mirrors to direct the laser beam to the processing site or surgical site. The so-called mirror joint method that leads to
There is an original fiber method that is currently being put into practical use. The mirror control system has problems such as operability during processing or surgery and misalignment of the mirror angle due to vibration, and in order to solve these drawbacks, it has been desired to put optical fibers into practical use as waveguides.

For CO2 laser light, KRG-6, a mixed crystal of thallium iodide and thallium bromide, is cited.

KRC-6 has the disadvantage that it will break if bent beyond a certain curvature, so it must be used carefully by limiting the curvature.

If the fiber breaks or melts due to localized heat concentration despite the curvature limitations, there is a risk that the high-power laser beam will penetrate the outer sheath and irradiate the patient or operator. there is a possibility.

In addition, the vapor generated when KH2-es melts may have some effect on the human body, so it is important to prevent fiber damage and constantly monitor the deterioration state of the original fiber. It was absolutely necessary to use the .

However, various monitoring methods have been tried in the past.

FIG. 1 shows a conventional fiber monitoring means. A conventional example will be explained with reference to FIG.

A laser beam 2-1 generated by the laser beam generating means 1 is condensed by the incident side condensing lens 3, and is incident on the source fiber 4 that transmits the laser beam.

The laser beam emitted from the original fiber is again focused by the emission-side condensing lens 6 in the hand piece 6 and guided to the affected area 7. Further, a part of the laser beam emitted from the original fiber is received and detected by a donut-shaped photodetector 8 surrounding this conical light beam. This photodetector generates a voltage output proportional to the energy of the laser beam incident on the original fiber when the original fiber is normal, but if the original fiber is fused for some reason, the voltage output is proportional to the energy of the laser beam incident on the original fiber. No output is generated and the state of the optical fiber can be known. This conventional configuration had the following drawbacks.

(1) In order to attach the photodetector to the output side, in addition to the original fiber for transmission, it is necessary to pass an electric wire through the original cable, and a connector for the electric wire is required to connect the original cable and the main body. However, the configuration of the small and lightweight original cable becomes complicated.

(2) It is impossible to use this configuration for an ophthalmic surgery type handpiece or an endoscope type handpiece.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional drawbacks, and provides a laser that can reliably monitor the deterioration or damage state of the original fiber and can be used with various types of handpieces. The purpose is to provide processing equipment.

Structure of the Invention The present invention comprises a laser beam generating means, a fiber for transmitting the laser beam generated by the laser beam generating means, an incident-side condensing lens for condensing the laser beam and making it enter the source fiber. an output-side condenser lens that condenses and images the laser beam emitted from the original fiber; and two or more lenses arranged at equal angles on the outer circumference of the conical light beam condensed by the input-side condenser lens. a group of light-receiving elements that receive reflected light from the original fiber; a balance calculation circuit that calculates the balance of the outputs of the group of light-receiving elements; and a central control system that recognizes the deterioration state of the original fiber from the output of the balance calculation circuit. It is a laser processing device equipped with a section.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 2 to 5. Figure 2 is a perspective view of the exterior of a No. 002 laser scalpel as an example of a laser processing device, where 9 is a housing in which a C02 laser oscillation tube and a condensing lens for condensing a C02 laser beam emitted from the tube are incorporated, and 10 is a housing. Power supply and control unit, 11 is a curvature-limited protection tube in which an infrared original fiber such as KH2-5 is incorporated, 12 is a protection tube 11
A connector part 13 for fixing the fiber to the housing 9 is a hand piece incorporating a condensing lens for condensing infrared light emitted from the original fiber.

FIG. 3 is a configuration diagram of main parts, and FIG. 4 is a front view of a group of light receiving elements.

A CO2 laser beam 15 emitted from the C02 laser oscillation tube 14 is focused by an incident side condensing lens 16 and enters the input end 17a of the original fiber 17. The laser beam emitted from the output end 17b of the original fiber is focused by the output side condensing lens 18 and guided to the affected area 19.

Reference numeral 20 denotes a group of light receiving elements composed of thermisters and thermocouples, which are arranged concentrically outside the conical beam of incident light.

The light receiving surfaces 21a, 21b, and 21c are surfaces that receive reflected light emitted from the input end 17a of the optical fiber, and 22
A, b, and c are portions that are shielded from emitted reflected light. The infrared rays incident on the light receiving surface are converted into thermal energy at the light receiving surface, and the hot junctions 23-a, 23-b, 2
3-c and cold junction 24-a.

The thermocouples 24-b and 24-c convert the thermal energy into electrical outputs va, vb, and vc according to the heat energy.

The electrical outputs va, vb, and vo are processed by the balance calculation circuit 25, and from the output, the central control unit 26 detects the fiber condition and immediately removes CO2 if there is an abnormality.
Perform safety measures such as stopping the oscillation of the laser oscillation tube.

Next, the operation will be explained. The GO□ laser beam 16 focused by the incident-side condensing lens 16 enters the optical fiber 17a, and most of the laser beam exits from the output end 17b to incise and evaporate the affected area 19. Further, some of the laser beams are transmitted to the fiber input end 17a and the output end 17b.
And it was reflected.

The reflected light 27 is emitted from the incident end 17a.

Generally, light that passes through a polycrystalline fiber such as KH2-5 is emitted at a wider angle than the angle at which it enters the optical fiber due to scattering at the crystal boundary, the surface condition of the original fiber, etc.

FIG. 5 shows the state of the fiber, the outputs va, vb, v0 of the thermocouple groups 23 and 24, the output V of the balance calculation port IM,
This is what is shown.

The upper row shows the original fiber, the incident laser beam, and the reflected laser beam.From the left, the original fiber (when it is normal (NORMAL)), and when the original fiber is damaged (Ab
FIG. 3 is a state diagram showing a case where the optical fiber is fused and melting is progressing (abnotmal ll );

The lower stage includes light receiving surfaces 21-a, 21-b, 21
− Output va of infrared light incident on c converted into electrical output
.

vb + vc, which indicates the angular distribution of reflected light.

The middle row shows the balance values of va, vb, and vo, and shows the degree of bias of the angular distribution.

If the original fiber is normal, the angular distribution of the reflected light will be less biased and va, vb, and vo will maintain their values, and the balance value will be close to 0. However, when a scratch occurs on the original fiber, the reflected light spreads due to diffuse reflection from that part, causing a bias in the angular distribution and increasing the balance value VB. In addition, if this flaw progresses and melts, and the melting point progresses, the angular distribution va.

Vb and vo fluctuate, and the balance value fluctuates greatly.

In other words, the condition of the original fiber can be determined based on the balance value VB.The central control unit 26 constantly monitors the balance value and if it determines that there is an abnormality, it can stop the C02 laser oscillation tube, etc. Take safety measures.

As described in detail, according to the present invention, the angular distribution of reflected light from the input end of the original fiber is detected by a group of light receiving elements, and the state of the original fiber is centrally controlled using the balance value calculated from the output. Since the part is constantly monitored, if there is an abnormality, it is possible to immediately take corrective action such as stopping laser oscillation. By installing a detector on the input side, the configuration of the source cable is simpler, and various It is possible to respond to various types of handpieces.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram of a conventional laser processing device, FIG. 2 is a perspective view of a laser processing device according to an embodiment of the present invention, and FIG.
4 is a plan view of some parts of the device, and FIG. 6 is a waveform diagram for explaining the device. 14... Laser beam generating means, 15...
・Laser beam, 16...Incidence side condensing lens, 17
...Original fiber, 18 ... Output side condensing lens, 20 ... Light receiving element group, 26 ...
Balance calculation circuit, 27... central control section. Name of agent: Patent attorney Toshio Nakao and one other person
B;-] Figure 2 Figure 4 Y (-1)

Claims (1)

[Claims] a laser beam generating means, a fiber for transmitting the laser beam generated by the laser beam generating means, an incident-side condensing lens for condensing the laser beam and making it enter the original fiber, and a fiber for transmitting the laser beam emitted from the laser beam. Shi ~ the former af:
An output-side condenser lens for condensing and image-forming, and two or more lenses arranged at a pen angle on the outer circumference of the conical light beam condensed by the input-side condenser lens to receive reflected light from the original fiber. A laser processing apparatus 0 includes a group of light receiving elements that performs a photodetection process, a balance calculation circuit that calculates the balance of the outputs of this group of light reception elements, and a central control unit that recognizes the deterioration state of the optical fiber from the output of the balance calculation circuit.