JPS63106717A - Laser beam transmitter - Google Patents

Abstract

PURPOSE:To prevent interception of a laser beam and extremely reduce energy loss by omitting an aperture which intercepts a part of the laser light and directly attaching a light detecting means to a reflecting mirror. CONSTITUTION:Output signals 7e of light detecting means 7d directly attached to reflecting mirrors 5 and 6 are operated by a CPU 8, and a motor 4a is driven through a motor driving signal 9a from a driving circuit 9 based on the signal from the CPU 8 to change the angle of a first reflecting mirror 4 so that a laser light 2b is projected to the center of a second reflecting mirror 5. Reflecting mirrors 5 and 6 are controlled as the first and second reflecting mirrors, and the positional deviation of the optical axis of the laser light is detected by the light detecting means of the reflecting mirrors at the down stream side to successively adjust the angles of reflecting mirrors at the upstream side, and thereby, the laser light 2 is transmitted to pass centers of all reflecting mirrors. Thus, the energy loss is reduced and the laser light is always transmitted with the beam position fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an improvement in a transmission device that transmits laser light (hereinafter also referred to as a laser beam) with small energy loss.

[Conventional technology]

First, a conventional laser beam transmission device will be explained with reference to FIGS. 4-5(a) and (b). Fig. 4 is an explanatory diagram showing a conventional device equipped with a beam transmission duct for transmitting laser light, Fig. 5 (a) is a front view showing a beam position detection device used in the conventional device, and Fig. 5 (b) is the same. FIG.

In the figure, (1) is a laser oscillator that oscillates a laser beam (2), and (3) is a beam transmission duct through which the laser beam (2) passes. (4), (5), and (8) are reflecting mirrors that reflect the laser beam and change the optical path, and are arranged in each bent portion of the beam transmission duct (3).

The reflecting mirrors (4) and (5), and (5) and (6) are arranged to face each other. , (4a), (5a), (
8a) is an angle adjustment mechanism provided in each of the reflecting mirrors (4), (5), and (8), which adjusts the optical path of the reflected laser beam by changing the direction of the mirror (that is, the angle of the mirror); is used to change the direction of the mirror.

(7) is a beam position detection device that is placed near the upstream side of the reflecting mirrors (5) and (111), respectively, and is installed in the beam transmission duct (3). As shown in FIGS. 5(a) and 5(b), this beam position detection device (7) includes an annular aperture (7b) in which a through hole (7a) with a predetermined inner diameter is formed in the center, and The four holes (7c) are located symmetrically with respect to the center of the laser beam (7b), are distributed in the circumferential direction, and are installed in four holes bored in the axial direction (7c), and detect the laser beam and output a signal. It is composed of a light detection means (7d). Also, this beam position detection device (7)
is arranged so that its center coincides with the center line connecting the centers of the opposing bifocal mirrors.

(8) is the light detection means (7d) of the beam position detection device (7).
) central processing unit (hereinafter referred to as CP) that calculates the output signal from
U), (9) controls each motor (4a), (5a), (6a) based on the signal from this CPU (8).
The CPU (8) and the drive circuit (9) control the angle adjustment mechanism (4a) of each of the reflecting mirrors (4), (5), and (8).

Control means (10) for controlling (5a) and (8a), respectively.
).

A conventional laser beam transmission device is configured as described above,
The axially symmetrical laser beam (2a) emitted from the laser oscillator (1) is reflected by a reflecting mirror (4) to change its optical path, and then enters the reflecting mirror (5) as a laser beam (2b). . When the optical axis (center line of the beam bundle) of this laser beam (2b) is shifted from the center of the reflecting mirror (5), differences will occur in the signals output by each of the four light detection means (7d). After calculating this output signal (7e) in the CPU (8), the drive circuit (8) sends a motor drive signal (9a) to the motor (
4a) to change the mirror angle of the reflecting mirror (4) so that the laser beam (2b) is irradiated toward the center of the reflecting mirror (5).

The above explanation is for the case where the motor (4a) of the reflector (4) is controlled for the reflector (5), but the motor (4a) of the reflector (6)
Similarly, if the motors (5a) of the reflecting mirrors (5) are controlled sequentially, the laser beam (2) is transmitted so as to pass through the center of each reflecting mirror.

[Problem that the invention seeks to solve]

A laser beam generally forms a mode with an energy distribution, but in the conventional laser beam transmission device as described above, a sixth mode is formed before passing through the beam position detection device (7).
When the laser beam (2) having the energy distribution (E) as shown in figure (a) passes through the beam position detection device (7), the laser beam is Part of the surrounding area is blocked. As a result, as shown in Figure 6(b), the base part of the laser beam mode (
The shaded area in the figure) represents energy loss, and as a result, the energy distribution of the laser beam after passing through the detection device (7) becomes as shown in (El). In addition, Fig. 6 (a), (b)
) The vertical axis (x) in the middle shows position, and the horizontal axis (y) shows energy.

Therefore, in the past, there was a problem in that the energy loss of the laser beam in the beam position detection device (7) was large.

This invention was made in order to solve these problems.9 It is possible to almost eliminate the energy loss of the laser beam due to the beam position detection device in the beam transmission duct, and it is also possible to The object of the present invention is to obtain a laser beam transmission device capable of transmitting a laser beam such that the centers thereof coincide with each other.

[Means for solving problems]

The first reflecting mirror is provided with an angle adjustment mechanism for adjusting the optical path of the reflected laser beam, and the second reflecting mirror is arranged opposite to the first reflecting mirror.
The laser beam reflected by the first reflecting mirror is reflected again by the reflecting mirror to change the optical path, and a light detection means for detecting the laser beam and outputting a signal is attached to the center of the second reflecting mirror. At least three of them are arranged at symmetrical positions, and a control means controls the angle adjustment mechanism of the first reflecting mirror based on the output signal of each of the light detection means.

[Effect]

In this invention, since the light detection means is directly attached to the reflecting mirror, there is no need to provide an aperture to support the light detection means.

〔Example〕

Hereinafter, based on an embodiment of the present invention shown in Figs. 1 to 3 (a) and (b), the same or equivalent parts as in the prior art will be given the same reference numerals, and the features of the present invention will be mainly described. explain. FIG. 1 is an explanatory view of the apparatus of this embodiment and corresponds to FIG. 4, FIG. 2(a) is a front view of the reflecting mirror, FIG. 2(b) is a side sectional view, and FIG. ) is an explanatory diagram corresponding to FIG. 6(a) showing the energy distribution of the laser beam before reflection by the second reflecting mirror in the device of this embodiment, and FIG. FIG. 6 is an explanatory diagram corresponding to FIG. 6(b) showing energy distribution.

A feature of the present invention is that the light detection means, which was conventionally attached to the aperture, is attached directly to the reflecting mirror.

That is, in the figure, (4) is provided with an angle adjustment mechanism (4a) that reflects the incident laser beam (2a) to change the optical path and changes the direction of the mirror to adjust the optical path of the reflected laser beam (2b). It is a reflecting mirror and has the same structure as the conventional one, and this embodiment shows a case where a motor (4a) is used as the angle adjustment mechanism. (5) is arranged opposite to this reflecting mirror (4), and the laser beam (2b) reflected by this reflecting mirror (4)
It is a reflecting mirror that reflects the light again to change the optical path, and is equipped with a motor (5a) similar to the motor (4a) described above. This reflecting mirror (5) is shown in FIG. 2(a).

As shown in (b), the laser beam is detected and the signal (7e)
At least three light detection means (7d) for outputting the light are arranged at symmetrical positions with respect to the center of the reflecting surface (a) of the reflecting mirror (5). The light detection means (7
d) shows the case where it is installed in the hole (7c) formed in the reflector (5), and two sets are installed perpendicularly at symmetrical positions with respect to the center of the reflector (5). That is, the case where a total of four are arranged is shown. Note that the reflecting mirror (6) and the motor (6a) provided on the reflecting mirror (6) also have the same configuration as the reflecting mirror (5) and motor (6a).

(8) is a CPU that calculates the signal (7e) from the light detection means (7d), and (9) is a CPU that calculates the signal (7e) from the light detection means (7d).
a), and in this embodiment, the CPU (e) and the drive circuit (9) control the angle adjustment mechanisms (4a), (5a)', and (13a), respectively. (10) is shown, but CP
U(8) is omitted and the motors (4a), (5a), ([la) are controlled by manually operating the drive circuit (9) of the control means (10) based on the signal (7e). You may also do so.

Next, the operation of the device according to the present invention will be explained. Assuming that the reflecting mirror (4) is a first reflecting mirror and the reflecting mirror (5) placed opposite to this first reflecting mirror (4) is a second reflecting mirror, first, the first reflecting mirror (4) The axially symmetrical laser beam (2b) reflected at the center of the mirror enters the second reflecting mirror (5). When the optical axis of this laser beam (2b) is shifted from the center of the second reflecting mirror (5), four light detection means (7d)
There will be a difference in the signal (7e) emitted by each of the laser beams depending on the intensity of the received laser light. For example, the point at which the difference between the upper and lower output signals of the light detection means (7d) in FIG. 2(a) is zero, and the difference between the left and right output signals is zero, is
This is the center of the second reflecting mirror (5), but when the difference is not zero, the optical axis and the center of the mirror are misaligned. Therefore, after calculating this output signal (7e) by the CPU (8),
Based on the signal from the CPU (8), the drive circuit (8) drives the motor (4a) via the motor drive signal (9a) and changes the mirror angle of the first reflecting mirror (4). The laser beam (2b) is made to irradiate the center of the second reflecting mirror (5).

Next, the same control as above is performed using the reflecting mirrors (5) and (8) as the first reflecting mirror and the second reflecting mirror, respectively, so that the optical axis of the laser beam is detected by the light detection means of the downstream reflecting mirror. By detecting the positional deviation of the mirrors and sequentially adjusting the angles of the upstream reflecting mirrors, the laser beam (2) is transmitted so as to pass through the center of each reflecting mirror.

Therefore, in the apparatus of the above embodiment, the laser beam (2) having the energy distribution (E) as shown in FIG. 3(a) before being reflected by the second reflecting mirror is 7d),
As shown in Fig. 3(b), only a slight energy loss (the shaded area in the figure) occurs due to the hole (7c) etc., and the energy distribution after reflection (Fig. 3(b) E) in the middle causes almost no change from the energy distribution before reflection.

Note that the reason why the above-mentioned slight energy loss does not extend to the X-axis is that the laser light causes a diffraction phenomenon.

Therefore, according to the present invention, a laser beam can be transmitted with little energy loss and a constant beam position.

Note that each of the above-mentioned signals (7e) and (9a) may be an electrical signal, but may also be an optical signal or other signal.

In addition, although the above embodiment shows a case where there are three reflecting mirrors, four reflecting mirrors are used.
It may be more than one sheet.

〔Effect of the invention〕

As explained above, this invention has a configuration in which the light detection means is directly attached to the reflecting mirror without the aperture that blocks part of the laser beam, so that the laser beam can be prevented from being blocked and energy loss can be reduced. It has the advantage that it can be made extremely small.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and FIG. 2 (a
) and (b) are the same front view and side sectional view of the reflecting mirror, respectively. Figures 3 (a) and (b) are explanatory diagrams showing the energy distribution before and after reflection, respectively. Figure 4 is the conventional device. FIGS. 5(a) and 5(b) are a front view, a side sectional view, and FIG. 6(a) of the beam position detection device, respectively.
) and (b) are explanatory diagrams showing the energy distribution before and after the passage, respectively. (2)... Laser light, (4)... First reflecting mirror, (5)... Second reflecting mirror, (4a), (5a)... Angle adjustment mechanism (motor)
, (7c)...hole, (7d)...light detection means, (7e)...output signal from the light detection means, (8)...
- Central processing unit, (10)...control means. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (4)

[Claims] (1) A first reflecting mirror provided with an angle adjustment mechanism for adjusting the optical path of the reflected laser beam; and a first reflecting mirror disposed opposite to this first reflecting mirror, which reflects the laser beam reflected by the reflecting mirror again and passes the optical path. a second reflecting mirror for changing the light intensity; at least three photodetecting means arranged symmetrically with respect to the center of the second reflecting mirror for detecting laser light and outputting a signal; A laser beam transmission device comprising: control means for controlling the angle adjustment mechanism of the first reflecting mirror based on an output signal of the means. (2) The laser beam transmission device according to claim 1, wherein the light detection means is installed in a hole formed in the second reflecting mirror. (3) The light detection means described in claim 1 or 2 is characterized in that two sets of the light detection means are disposed at symmetrical positions and perpendicular to each other with respect to the center of the second reflecting mirror. Laser beam transmission device. (4) The control means for controlling the angle adjustment mechanism of the first reflecting mirror includes a central processing unit that calculates a signal from the light detection means. The laser beam transmission device according to any one of Item 3.