JPS58103623A - Monitoring device for exit energy of optical fiber - Google Patents

Abstract

PURPOSE:To permit monitoring with good accuracy at all times by providing a light energy detecting element on the outer side of a circular conical luminous flux incident to the condenser lens between a condenser lens and the exit end of an optical fiber. CONSTITUTION:A light energy detecting element 15 for detecting part of the energy emitting from an optical fiber 11 without shielding the light incident to a condenser lens 12 is provided between the lens 12 and the exit end 11a of the fiber 11. The lens 12 is fixed by a lens hlder 16, and the light condensed by the lens 12 advances like an optical path 14. A cylindrical housing 17 contains the fiber 11, the lens 12 and a light energy detecting element 15. An amplifying and converting circuit 18 which amplifies the signal from the element 15 and converts the same to energy and an energy display 19 are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a laser beam processing device or a laser surgery device that uses an optical fiber as an optical waveguide. The purpose of the device for monitoring fertilization is to provide one that can perform constant monitoring without interrupting monitoring even during processing or surgery.

Laser processing equipment or laser surgery equipment that uses CO-rich laser light guides the laser light to the processing site or surgical site (normally, a mirror joint waveguide consisting of a plurality of mirror collars is used, but a mirror joint i* The m-waveguide has problems in terms of operability and misalignment due to angular vibration, and in order to solve these drawbacks, the use of optical fibers as waveguides is being considered.

Figure 1 shows the leading wavepath and light condensing part of a laser processing device or laser surgery device that uses an optical fiber as the leading wavepath. The light beam (
! I) is condensed into a light beam (6) by the condensing lens (I) of ill, and enters the input end of the optical fiber (3). The light guided inside the optical fiber (2) is emitted from the output end of the optical fiber (3) as a light beam [7],
The workpiece or surgical object is placed at a focal point of 4iL by the @2 condenser lens (4), and processing or surgery is performed using high-density light energy.

In laser processing or laser surgery, the energy emitted near the focal point is directly used, so it is necessary to monitor the amount of emitted energy. Either the output energy is monitored, or a mirror is provided near the exit of the laser light source at an angle of 45 degrees with respect to the optical axis, and the laser beam is bent by 90 degrees and guided to a laser beam detector for measurement. In either method, the optical energy emitted from the laser light source is monitored, but the optical energy actually focused on the focal point is not monitored.When using an optical fiber as a waveguide, Even if it is known that the incident energy to the KLX optical fiber is large due to reflection loss and its aging change at the input end and output end of the optical fiber, and light loss inside the optical fiber and its aging change, etc., the output energy cannot be determined. It's not surveillance. As an extreme case, if the optical fiber is broken in the middle, the output energy will be zero regardless of the incident energy, and it is clear that monitoring cannot be performed. In addition, in the case of a method in which a mirror is installed near the exit of the laser light source and the laser beam is bent 90 degrees and measured with a photodetector, the laser output must be monitored because the mirror must be placed on the laser beam path. It is not possible to perform machining or surgery with a telescope that is closed, and conversely, when machining or surgery is being performed, the laser output cannot be measured because the mirror is removed from the laser beam path.
Therefore, there is a drawback that output energy cannot be monitored.

Therefore, the present invention provides an optical fiber, a condenser lens that condenses one light energy emitted from the optical fiber, and a cone-shaped light beam that enters the condenser lens between the condenser lens and the output end of the optical fiber. A light energy detection element disposed on the outside that receives and detects light energy emitted from the optical fiber, a processing circuit that converts the signal from the light energy detection element into an energy value, and the a result of this J611111 route. The optical fiber is equipped with an energy display means to directly monitor the optical energy emitted from the optical fiber, and can be monitored at any time even during processing.

Before entering into the description of the present invention, the properties of light emitted from an optical fiber will be explained.

The optical energy emitted from the optical fiber is emitted radially from the optical fiber output end. Figure 112 (@) shows the constant distribution of light energy emitted from the optical fiber, where the horizontal axis is the angle with respect to the optical axis of the optical fiber, and the vertical axis is the energy. gsf1 diagram (b
) is ξ where the light emitted from the optical fiber is emitted radially.
In this figure, Φ) is the optical fiber, (9a) is the output end of the optical fiber (11), and Z is the optical fiber (.)
shows the optical axis of The light emitted from the optical fiber (11) decreases rapidly as the angle increases when the optical axis is close to zero, but beyond a certain angle, the decrease becomes more gradual, as shown in Figure 2 (Otori). It is an expanded form of Kii. now,
Assume that 90% of the total emitted energy is within the range defined by angle 01, and -6% is within the range defined by angle #. When installing a condensing lens aligned with the optical axis to condense the light energy emitted from the above optical fiber ←), do you use 90% of the total emitted energy?
Depending on whether 96% is used or not, there will be a considerable difference in the lens aperture of the condenser lens. - As an example #, = 16°
, θ snow = so”, the output end (嘗a) of the optical fiber object)
If the distance from to the condensing lens is 4C1l, SO%
The lens aperture when using is approximately I C1@'v
In the case of 95% utilization, it is approximately 2C1lφ. The lens aperture must be limited to a certain value due to constraints such as operability9 weight and cost, so in the above case, if the lens aperture is set as fan-, 10% of the total emitted energy will be effectively used. I'm afraid of being thrown away. However, even if the lens aperture is set to Ran-, S% is not used effectively, and in principle, even if the lens aperture is made larger, it is impossible to utilize 100% of the total output energy. In the present invention, the output energy is monitored by using the energy distributed outside the lens aperture of the condenser lens like ξ and discarded without being used for processing or surgery. An example of this is shown in Figure 8-I! This will be explained based on FIG.

FIG. 8 is a concrete layout diagram of the energy monitoring device emitted from the optical fiber according to the present invention, and (b) shows the optical fiber 1<-1
(11!l) is the output end of the optical fiber (b), the brocade is the condenser lens, the square is the line indicating the maximum output angle of the optical path of the light that enters the condenser lens from the optical fiber 〇Xu, and the axis is the condenser lens (
Line (2) indicates the optical path of the light condensed by 66 is a lens holder for fixing the condensing lens (2), αη is a cylindrical housing, which includes an optical fiber so, a condensing lens, and the light energy detecting element (2). ). (to) is an amplification conversion circuit for amplifying, converting energy of the signal from the optical energy detection element) [
Processing circuit], the ring is an energy display means. .

Of the light emitted from the output end (Ua) of the optical fiber casting, the light emitted at a wide angle also enters the light energy detection element (Ua), is absorbed and converted into energy, and the temperature It becomes an electrical signal corresponding to the rise. Since the ratio of the energy incident on the optical energy detection element to the total energy emitted from the optical fiber (b) is known, the signal from the optical energy detection element is converted to the total output energy or concentrated light by the amplification conversion circuit. It is possible to constantly monitor the energy value condensed at the focal point by converting it into the energy value incident on the lens (2) and displaying it on the energy display means. Another feature of this optical energy detection element is that there is no energy loss.
An example of this is shown in FIG. 4, where z is a thermopile consisting of a plurality of thermocouples connected in series, and @(2) is ii t *th, which constitutes each thermocouple constituting the thermopile (2). The wire or foil or ring made of metal from No. 2 is No. 1. The first contact point of the ring with the second metal, (2) is the second contact point as well, (2) is the output curry V wire of the thermopile Z, and Z is the heat capacity to support the thermopile 4. a small substrate, (2) is a container that houses the thermopile array and the substrate (2), - is a part of the container, and the light emitted from the optical fiber axis is incident on each second contact point 0. This is a shielding ring that prevents this from happening. The first contact point (2) of each thermocouple constituting the thermopile array is placed on a slightly larger circumference than the circumference determined by the optical path (2) so as to receive the energy emitted from the optical fiber casing. Each second contact point (2) is configured with a shielding ring to prevent light from the optical fiber (b) from directly hitting it, thereby forming a cold junction. Also, the sum of thermocouples is obtained.

The distribution of light energy emitted from the optical fiber 01 is not uniform depending on the material of the optical fiber (b) and the manufacturing process. For example, if we look at the energy distribution on the circumference of a certain radius centered on the optical axis Zeng, the energy distribution will not be the same even though it is on the circumference of the same radius. Therefore,
Estimating the total energy by measuring only one point on the same circumference in order to measure light energy having such a non-uniform energy distribution causes many errors.

In the present invention, the above problem is solved by arranging a large number of thermocouples on the same circumference and performing energy addition, that is, integration, at each point in consideration of point B.

In addition to copper-constantan, various commonly used combinations of metals can be used as thermocouple materials.The concrete structure is as shown in Figure 4 (s+), in which thin thermocouple wires are connected alternately. In addition to the case where the thermocouple material has a shape of 1ζ, it is also possible to form a thin film of the thermocouple material by vacuum evaporation to form a pile with a small heat capacity.

FIG.

- is a comparison circuit, ■ is a reference voltage generation circuit, a bell is a control alarm device, and a ring is an output setting means for setting the emitted light energy. Now, the output setting method from the optical fiber (2)
Suppose that the energy set by is radiated in both directions. The optical energy detection element generates an output signal corresponding to this emitted energy, which is amplified and converted by the amplification and conversion means, and then input to the comparison circuit (2). A voltage corresponding to the setting position of the output setting means (2) is generated in the reference voltage generation circuit (2), and this reference voltage V7 and the output voltage v8 of the amplification/conversion means (2) are compared in the comparison circuit (2). Ru.

If the optical fiber (b) breaks for some reason, as a result, the optical fiber (l force output end (tta)
), when the light energy is no longer emitted from the light energy detection element (2), the signal generated in the light energy detection element (2) disappears, and the comparison circuit shaft detects this and outputs an abnormal signal, and the control alarm device -
to turn off the laser light source or issue an alarm to notify the operator of abnormal conditions.

By setting ξ, it is possible to easily monitor not only the output energy but also the breakage of the optical fiber (2), changes in characteristics, etc.

As explained above, the present invention has the major feature of directly, accurately, and constantly monitoring the energy emitted from the optical fiber, and also has the major feature that the energy emitted from the optical fiber is monitored at all times with high precision. This has the advantage of not losing any light energy. Therefore, it is applicable to all laser processing devices and laser surgery devices. Furthermore, since a thermoelectric conversion element is used as the energy detection element, it is particularly effective for laser processing equipment in the infrared region, such as YAG laser, CO, and laser.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a leading wavepath and a condensing part of a laser processing device or laser surgery device using an optical fiber,
Fig. gg is an explanatory diagram of energy distribution of light emitted from an optical fiber, Fig. 118 is a configuration diagram of an optical fiber emitted energy monitoring device according to the present invention, and Fig. 4 is a cross-sectional view of a main part of an optical energy detection element along the line A-A. FIG. 6 is a configuration diagram showing an application example. a......Optical fiber, (2)...
...Condensing lens,) ......Light energy detection element, God ......Lens holder, Nobu ......Cylindrical housing, (To)・・・・・・・・・
・Amplification conversion means, So...Energy display means, So...Thermopile, -...:...
・・1st contact point, Sakaki・・・I= contact point, ■・・・・・Lead wire, )・・・・・・・
... Board, (2) ...... Customer equipment, -...
・・・・・・Shielding ring, −・・・・Comparison circuit, Zeng・・Standard voltage generation circuit, (to)・・・・
...Control alarm device, -... Output setting means agent Kazuhiro Morimoto Figure 1 Figure 2 [Figure 3 C2L] (1,)

Claims (1)

[Claims] 1. An optical fiber, a condensing lens that condenses the light energy emitted from the optical fiber, and a conical shape that enters the condensing lens at the threshold of the output end of the condensing lens and the optical fiber. a light energy detection element disposed on the outer side of the light beam to receive and detect the light energy emitted from the optical fiber; a processing circuit for converting the code from the light energy detection element into an energy value; An optical fiber output energy monitoring device comprising energy display means for displaying circuit processing results. Claim 1, wherein the L light energy detection element has a ring shape surrounding the conical light beam and is configured to produce an output proportional to the light energy incident on the entire ring-shaped light receiving surface. Industrial optical fiber output energy monitoring device. 8. Where! 2. The optical fiber emitted energy monitoring device according to claim 1, wherein the optical fiber output energy monitoring device is configured to compare the output of one circuit with a reference voltage to detect breakage and characteristic deterioration of the optical fiber, and to activate an alarm device when an abnormality occurs. 4. Optical energy, - The detection element is constructed by connecting a plurality of thermocouples in series, arranged on the same plane so that each thermocouple receives and receives the first light, and the W of each thermocouple is 2. The optical fiber emitted energy monitoring device according to claim 2, wherein a cold contact is formed by disposing the second contact at the rear of the ring-shaped light shielding plate so as not to receive the optical energy from the optical fiber. .