JPS62257780A - Laser device - Google Patents

Abstract

PURPOSE:To correct the displacement of beams, and to obtain laser beams at a beam mode having excellent symmetry by providing a beam-position detecting means by an element detecting beams projected to an aperture bored on the arbitrary axis of laser beams and the outer circumference of the opening section of the aperture and a cooling means for the detecting element. CONSTITUTION:A laser medium 9 is caused to flow, and excited by discharge 4, and laser beams at a single mode, a skirt of which is spread, are formed between a partial reflection mirror 5 and a total reflection mirror 6. An internal standing wave having the shape of laser beams is projected to an aperture 7, the end of the skirt is cut and circular beams 10 are extracted through the mirror 5. A beam-position detecting means 80 in the front of the aperture 7 has four beam detecting elements 84 with light-receiving plates 84 on the outer circumference of a hole 81, and senses an output from the skirt section of the internal standing wave while flowing cooling water 86 through a path 85 and prevents heat radiation to the beam detecting elements 88 from an aperture 82. Accordingly, the speed of response of the elements 88 is accelerated, the internal standing wave can be detected precisely in a short time, and the angles of the mirrors for a resonator are adjusted, thus acquiring an output at a bean mode having excellent symmetry.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser device equipped with a laser beam position detection means.

[Conventional technology]

Figures 9(a) and (b) are for example Japanese Patent Application No. 1152/1986.
73 is a configuration diagram showing a conventional laser device and a front view showing a laser beam position detecting means. FIG.

In Figure 9(a), (1) is a high voltage power supply, +2
1. +3) are the respective electrodes arranged facing each other, (
4) is the discharge generated at each electrode f21, +3) jil, +51Vi partial reflection mirror +, f6+ is a total reflection mirror, (7) is the aperture of the mode selection piece disposed near the partial reflection mirror (5). , (8) are disposed in the optical path of the laser beam, facing the aperture (7) of the mode selection piece, and located inside the laser device from the aperture (71) of the mode selection piece, that is, aperture 1.
7) laser beam position detection means provided on the front surface 1411, (9I is the gas flow of the laser medium gas, which flows in a direction perpendicular to the plane of the paper as shown in FIG. 9(a).
Q is a laser beam generated by this laser equipment and taken out to the outside.

In FIG. 9(b), (8a) is an aperture member constituting the laser beam position detection means (8);
))) was provided on the optical axis of the laser beam, which is the center of this aperture member (8a). It is a circular opening having an opening diameter A, and (Bc'r is this opening (8b)
A plurality of laser beam detection elements, for example four in this case, are mounted on the outer periphery of the laser beam at equal intervals in the circumferential direction.

This laser beam detection element (8C) is made up of a thermopile, thermocouple, etc., for example.

Next, the operation will be explained. First, each electrode (2).

(3) Apply a high voltage from the power supply (1) between each electrode f2
+, +3) to generate a discharge (4). On the other hand, each ′
The gas flow of the laser medium gas (9
). The laser standing wave generated by exciting the laser medium gas by discharge (4) has two directions: rightward (partial reflection mirror (51 direction)) and leftward, and the rightward standing wave is caused by the aperture of mode selection W ( The shape was determined at 71.

Partial reflection mirror (51K included), a part of which passes through the partial reflection mirror (51) and is emitted to the outside, while one reflected light is directed to the total reflection mirror (6), is reflected once again, and passes through the aperture (7).
Return to 1. In this process, the rightward standing wave undergoes optical amplification and at the same time becomes a beam shape with a long base and a widening base.The aperture (F) truncates the base, creating a circular laser beam. α1 can be taken out to the outside. On the other hand, the four laser beam detection elements (8C) installed in the front direction of the aperture ( ) 1 are part of the rightward internal standing wave power.

That is, it is possible to directly detect the laser beam incident on the outer periphery of the opening of the aperture member (8a), and the position of the laser beam is detected by comparing the outputs of these laser beam detection elements (8C). be able to.

For example, the center of the 1 nose beam is the aperture member (8a
), the mode shape of the laser beam will be distorted and significant processing defects will occur when the laser beam is used for processing, but in this case the output of the laser beam detection element (8C) will be clearly unbalanced. Therefore, it is detected that the shape of the laser beam mode is distorted as the cause of the processing defect. Therefore, by driving the total reflection mirror (6) or the partial reflection mirror (5) and adjusting their angle so that the difference between the signals from the laser beam detection element (8C) is minimized, By setting the laser optical path appropriately and correcting the deviation of the optical axis of the laser beam, it is possible to obtain a laser beam pattern with a well-symmetrical laser beam mode.

[Problem that the invention seeks to solve]

Conventional laser equipment is configured as described above, so
When applied to a high-power laser, the temperature of the laser beam detection element (8C) is improved by laser beam irradiation.For example, a sheathed thermocouple is used as a 17-the beam detection element (8C) in a CO2 laser with an output of 1500W. and 5
It got to about 00 degrees Celsius.

The heat accumulated in the laser beam detection element (8C) cannot escape, and the response of the laser beam detection element (8c) becomes slow, making it impossible to quickly detect the position of the laser beam. Therefore, there is a problem that the optical axis of the laser beam may be erroneously adjusted and switched before the output of the laser beam detection element (8C) becomes stable. Further, there is a problem in that radiation from the aperture member (8a) itself has an adverse effect on the laser beam detection element (8C).

This invention was made to solve the above problems, and it is possible to quickly detect the position of the laser beam, and by adjusting the resonator mirror using the signal from the laser beam detection element, the symmetry can be improved. The purpose of this invention is to obtain a laser device that can obtain a good laser beam mode.

[Means for solving problems]

The laser device according to the present invention is arranged in the optical path of the generated laser beam, and the laser beam is incident on the aperture member having an opening on the optical axis and the outer peripheral position of the opening of the aperture member. The apparatus is equipped with a laser beam detection means consisting of a plurality of laser beam detection elements for detecting the laser beam, and a cooling means for cooling the V-laser beam detection element.

[Effect]

The cooling means in this invention quickly cools the heat generated in the laser beam detection element by laser beam irradiation. K Cool down. Therefore, the response of the laser beam detection element is accelerated, and accurate internal standing wave output can be detected in a short time. By adjusting the resonator mirror angle so that the output difference between the plurality of laser beam detection elements is minimized, a laser beam in a laser beam mode with good symmetry can always be obtained. Furthermore, if the aperture member is cooled by the cooling means and the laser beam detection element is cooled by the cooled aperture member, the temperature increase of the aperture member due to laser beam irradiation can be prevented, and the 1
7-Heat radiation to the beam detection element can also be prevented.

〔Example〕

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

Note that in FIG. 1, the same reference numerals as in FIG. 9 indicate the same or corresponding parts.

In Fig. 1(a), (8Q1 is located opposite to the aperture ()) of the mode selection door, and from the aperture (7) of the mode selection door to the laser device inner center 1. That is, the aperture (71) is disposed on the front side. FIG. 1(b) is a laser beam position detection means according to an embodiment of the present invention.
), (C) is this laser beam position detection means (80)
FIG. 2 is a plan view and a cross-sectional view showing the configuration of FIG.

In FIGS. 1(b) and (C), (8) an aperture with an aperture diameter A located on the optical axis of the laser beam, (8)
2) is an aperture member having an opening (8));
88) A plurality of pieces at equal intervals in the circumferential direction on the inner circumference of the aperture member (82).

For example, with four laser beam detection elements installed.

(83) a temperature sensor; (84) a laser beam receiving plate attached to the front surface of the temperature sensor (a3);
(as) 1d Cooling means 0 For example, aperture member (8
2) A cooling water passage provided in the cooling water passage; the arrow (86) indicates the flow direction of the cooling water flowing through this passage. Figure 1 (d
) is a graph showing the light intensity distribution of the laser beam incident on the laser beam detection element (88), where the horizontal axis shows the distance r from the optical path axis 0, and the vertical axis shows the light intensity.

Also, as a means of adjusting the resonator mirror angle.

For example, it is constructed as shown in FIG. In the figure,
(91) is a mirror holder that holds a partial reflection mirror (5) and a total reflection mirror (6), respectively, and (92) a gear.

(93) is a stepping motor, (94) is a micrometer head, (95' Jtd bellows, (
96) is a stepping motor that outputs pulse voltage.
(97) is the mirror base, (98)
It shows the fulcrum.

Next, its operation will be explained. In Fig. 1 (c)), a discharge (4) is generated by applying a high voltage between each electrode (21, f3) from a power supply (2).On the other hand, a laser medium gas is applied to each electrode t2) and +3+f'tl. Flow the gas flow (9).

The standing wave of the laser generated by exciting the laser medium gas by discharge (4) has two directions: rightward (toward the partial reflection mirror (5)) and leftward (toward the partial reflection mirror (51)). As a result of amplification of the standing wave by reciprocating between (6), a laser beam mode (single mode) with a widened tail as shown in FIG. 1(d) is formed. When the internal standing wave having such a shape enters the aperture (7) of the letter mode selection piece shown in FIG. A circular laser beam aa can be extracted to the outside through the reflection mirror (5). During this process, the laser beam position detection means (80) disposed on the front side of the mode selection aperture (71) ), the internal standing wave passes through the opening (8)) shown in Figures 1(b) and (C),
Since the internal standing wave has a shape with a widened base, the laser beam receiving plates (84) of the four laser beam detection elements (88) provided on the outer periphery of this opening (8) are connected to the aperture member (8). The laser beam incident on the outer peripheral position of the opening 82) senses the output of the widened tail portion of the internal standing wave.

The internal standing waves generated here are incident on the laser beam output means (801), and a part of the output is received by the laser beam receiver @ (s4), which causes the temperature sensor (
The temperature of 83) increases, but this heat is transferred to the laser gas and
Since the laser gas diffuses into the aperture member (82), the temperature of the temperature sensor (83) becomes a constant value only when the temperature distribution of the surrounding laser gas and the aperture member (82) becomes constant. Furthermore, since heat accumulates in the aperture member (82) itself, the laser beam incident on the laser beam receiving plate (84) changes.

That is, even if the arrangement of the resonator is distorted and the shape of the laser beam changes, the temperature sensor (83) will still be able to control the aperture member (
82) The response is slow because the heat accumulated in itself does not stabilize until it changes in response to this change.

Therefore, by attaching the laser beam detection water element (88) to the aperture member (82) which is cooled by flowing the cooling water (86) into the cooling water passage (85), the laser beam detection element is always directed in a fixed direction. By emitting heat in the direction away from (88), the heat accumulated in the laser beam detection element (88) can be quickly released.

Furthermore, heat radiation from the aperture member (82) whose temperature has increased to the laser beam detection element (88) can also be prevented.

For example, FIG. 2 shows an embodiment of the present invention applied to a C02 laser with a laser output of tXW, and a laser beam detection element (8
8) When using a sheathed thermocouple, the response time of the laser beam detection element on the inertia shaft is C minutes).

It is a graph showing M axis Kl/-the beam detection temperature button). As shown in the figure, cooling of the aperture member (82) was able to reduce the response time to approximately 13-times between the response ridges of the conventional device.

In this way, it is possible to speed up the response of the laser beam detection element (88), and the laser beam detection element (88)
Since the sensor can accurately sense the laser beam output in a short time, by comparing the outputs with each other, accurate laser beam position detection can be performed. Therefore, for example, as shown in FIG.
96) angle.

Good symmetry can be achieved by adjusting the resonator mirror angle so that the output difference between the laser beam detection elements (88) is minimized by rotating and straightening the micrometer head (94) using the gear C92). A laser beam mode can be obtained.

Note that the temperature sensor (85) includes a sheathed thermocouple,
You can use a thermistor, platinum resistor, etc.

In the case of a sheath thermocouple, the outer shell of the sheath corresponds to the laser beam receiving plate (84).

Further, the opening (8) of the aperture member (82) for laser beam detection may also serve as the opening of the aperture (7) for mode selection.

Further, in the above embodiment, a cooling water passage (85) is provided inside the aperture member (82), and the cooling water is allowed to flow through the passage to cool the aperture member (82). A fin-shaped aperture member (82) as shown
Alternatively, as shown in Figure 5, a cooling fan (82) may be installed on the back of the aperture member (82) to provide forced air cooling. The same effect as in the above embodiment can be obtained.

As shown in FIGS. 6(a) and 6(b)K, a fin-shaped aperture member (82) may be cooled by a fan (87). In addition to the natural cooling effect provided by (82), this is further achieved by forced air cooling.

It is possible to obtain an even greater cooling effect.

Alternatively, in the above embodiment, the laser beam detection element (88
) is designed to be cooled, but it is also possible to use a cooled laser beam receiver (891) as shown in Fig. 1.In other words, in this case, The temperature sensor (83) is connected to the aperture member (
Instead of being mounted directly on the outer periphery of the aperture of the aperture member (82), it is mounted at a certain distance from the surface of the aperture member (82) and on the surface of the cooled laser beam receiving plate (89). There is an effect similar to that of the above embodiment.

Further, the arrangement position of the aperture (71) of the mode selection piece and the laser beam position detection means (80) according to the present invention is not limited to the above embodiment, but 1, for example, FIG.
) to (d). The arrangement may be such that the laser beam position detection means (80) can detect the output of the laser beam incident on the opening outer cylinder position of the aperture member.

In addition, in the above embodiment, CO generated by gas discharge
Although the case of two lasers has been described, it can of course be applied to X and CZ lasers, etc., and the effects of the above embodiment and colleagues can also be achieved with solid lasers such as ruby lasers and YAG lasers.

Further, the number of laser beam detection elements is not limited to four.

〔Effect of the invention〕

As described above, according to the present invention, there is an aperture member disposed in the optical path of the generated laser beam and having an opening on the optical axis of the laser beam, and an aperture member that is incident on the opening outer cylinder position of the aperture member. By providing a laser beam position detection means consisting of a plurality of laser beam detection elements for detecting the laser beam detected by the laser beam, and a cooling means for cooling the laser beam detection element, heat generated by laser beam irradiation can be transferred to the laser beam detection element. Since the laser beam can be quickly released without being stored in the laser beam, the response of the laser beam detection element is accelerated, and accurate internal standing wave output can be detected in a short time.

Therefore, by adjusting the resonator mirror angle so that the output difference between the laser beam detection elements is minimized, it is possible to obtain a laser device that can output a laser beam mode with good symmetry.

Furthermore, if the cooling means is configured to cool one laser beam detection element by cooling the aperture member, heat radiation from the aperture member to the laser beam detection element can be prevented, and the effect is even greater.

[Brief explanation of drawings]

Fig. 1(,)Fi is a configuration diagram showing a laser device according to an embodiment of the present invention, Fig. 1(1:,), and (C) are a front view and a sectional view of the laser beam position detection means in the same device. . The same figure (d) is a graph showing the intensity distribution of one laser beam incident on the laser beam position detection means, W, and the second figure shows the conventional laser beam position detection means and the laser beam position detection in one embodiment of the present invention. In the means, a graph showing the laser beam detection temperature with respect to the response time of the laser beam detection element, FIG. , FIG. 5 is a front view and a sectional view of the laser beam position detection means showing other embodiments of this invention, and FIG. 6(a),
(b) is a front view and a cross-sectional view of a laser beam position detecting means showing another embodiment of the present invention, and FIG. 1 is a cross-sectional view of the laser beam position detecting means showing still another embodiment of the present invention. , Fig. 8(a), (b), (c), (d
9(a) is a schematic diagram of a main part of a laser device showing still another embodiment of the present invention, and FIG. 9(a) is a schematic diagram of a conventional laser device. Figure ('b) is a front view showing the laser beam position detection means in the above apparatus. In the figure, (80) is a laser beam position detection means, (8)) is an opening, (8) is a laser beam, (80) is a laser beam position detection means, (8) is an opening,
2) is an aperture member, (851fi cooling means,
(88) is a laser beam detection element. In addition, in FIG. 9, the same reference numerals indicate the same or equivalent parts.

Claims (8)

[Claims] (1) An aperture member disposed in the optical path of the generated laser beam and having an opening on the optical axis of the laser beam, and a plurality of lasers that detect the laser beam incident on the outer peripheral position of the opening of the aperture member. 1. A laser device comprising: a laser beam position detecting means comprising a beam detecting element; and a cooling means for cooling the laser beam detecting element. (2) The laser device according to claim 1, wherein the laser beam detection element includes a laser beam receiving plate and a temperature sensor that measures the temperature of the receiving plate. (3) The laser device according to claim 1 or 2, wherein the cooling means cools the laser beam detection element by cooling the aperture member. (4) The laser beam detection element is configured to output to means for adjusting the resonator mirror angle so that the mutual output difference is minimized. The laser device according to any one of Item 3. (5) The laser device according to claim 4, wherein the means for adjusting the resonator mirror angle is configured to drive a stepping motor for adjustment. (6) The laser device according to claim 3, wherein the cooling means includes a cooling water passage provided in the aperture member, and the aperture member is cooled by the cooling water flowing through the passage. (7) The laser device according to any one of claims 1 to 5, wherein the aperture member has a fin shape. (8) The laser device according to claim 3 or 7, wherein the cooling means includes a fan provided near the aperture member, and the aperture member is cooled by the fan.