JPS60130935A - Laser beam transmitter - Google Patents

Abstract

PURPOSE:To control the optical position without losing the intensity distribution of laser beams by providing at least >=3 optical detecting means on a circle corresponding to a skirt of the laser beams. CONSTITUTION:Bases 12, 12' provided with holes 13, 13' having a diameter D are provided to two positions of a path of the laser beams whose optical axis position is adjusted by a transmission mirror 32 driven by a driver 31 and laser beam detecting elements 14, 14' are provided with equal distribution at four positions of the inner circumferential ridge of the holes 13, 13' of the bases 12, 12'. Through the constitution above, since the angle of the laser beam transmission mirror 32 is applied with feedback control by using the output of the laser beam detecting elements 14, 14', the control performance of the optical axis posiion is improved remarkably.

Description

[Detailed Description of the Invention] <Technical Field of the Invention> The present invention relates to optical axis position detection...! This invention relates to a highly efficient laser beam transmission device.

<Prior Art> As a conventional laser beam transmission device for the above-mentioned building, there is one shown in FIG. 1, for example.

That is, a partial reflecting mirror 2 that reflects a part of the laser beam is interposed in the laser beam 1, and the laser beam reflected by the partial reflecting mirror 2 is incident on a four-quadrant photodetector 3, and the four-quadrant light is The detector 3 is configured to detect the optical axis position of the laser beam.

However, in the conventional configuration described above, when the intensity of the laser beam such as a KW class CO2 laser is strong, the laser beam transmitted through the multi-partial reflecting mirror 2 is scattered due to distortion due to thermal strain of the partially reflecting mirror 2, etc. There is a risk that the laser beam intensity will drop significantly.

<Summary of the Invention> The present invention has been made in consideration of the above point KgM, and has a structure in which at least three or more light detection means are disposed on the circumference of the base of the laser beam. It is an object of the present invention to provide a laser beam transmission device that eliminates the above disadvantages.

<Embodiment of the Invention> An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

11 is, for example, a 1KWCO2 laser beam in TEMoo mode, 12 is a base in which a hole 13 with a diameter for passing the laser beam is formed, and 14 is a bolometer and a current collector arranged evenly at 94 locations on the inner peripheral edge of the hole 13. It is a laser beam detection element such as an element.

Next, how to select the diameter of the hole 13 will be explained.

The intensity distribution of a laser beam is generally the distribution shown in FIG. 3. Assuming that there is also a symmetrical intensity distribution on the negative value side of the radius r, the combined intensity distribution will be a normal distribution. Let the standard deviation at this time be σ, and ω. ω defined as −2σ. The radius rw1.5ω is 1.5 times the value of .

Within 99% of the total laser beam power is included, rwl, 5ω. Given the above, since only about 1% of the power is included, the diameter of the hole 13 is D=2r=3ω.

If so, the intensity of the laser beam 11 transmitted through the hole 13 is generally not affected. However, the light receiving area of the laser beam detection element 14 disposed at the inner peripheral edge of the hole 13 is, for example, 4.
(2) Since the laser power of about 2 mW is incident on the laser beam detection element 14, the energy is sufficient for detecting the optical axis position. For example, if the optical axis of the laser beam 11 deviates by about l-, the intensity of the laser beam incident on the laser beam detection element 14 located on the anti-eccentric side will be expanded. This shows that it has sufficient position detection ability.

FIG. 4 shows a modification of the above embodiment, in which one end side of the optical fiber 21 is provided evenly distributed at four locations on the inner peripheral edge of the hole 13 of the base 12, and the optical fiber 21 A 4o"t", L/-f beam detection element 2 configured to have a laser beam detection element 22 facing the other end and guide the laser beam to an arbitrary position through an optical fiber 21.
2 improves detection accuracy by avoiding the influence of electrical noise from the laser beam generator. In addition, with this configuration, the laser beam detection element can be made larger, and detection accuracy can also be improved.

FIG. 5 shows a second embodiment, in which a transmission mirror 32, which is rotatably driven by a drive device 31, is arranged coaxially at two points in the path of the laser beam, which can adjust the optical axis position. Base 12, 12' with holes 13, 13'
At the same time, laser beam detection elements 14 and 14' are equally distributed at four locations on the inner periphery of each of the holes 13 and 13' of these bases 12 and 12'.

In such a configuration, the laser beam transmission mirror 32 is adjusted in degrees so as to minimize the output difference between the four laser beam detection elements 14 and 14' mounted on each base 12 and 12', respectively, which face each other. If this is feedback-controlled via the drive device 31, the control performance of the optical axis position can be significantly improved.

FIG. 6 shows a modification of the second embodiment, in which one end side of the optical fibers 21, 21' are evenly distributed at four locations on the inner peripheral edge of each hole of the base 12, 12'. In addition, a laser beam detection element 22.22' is provided at the other end of the optical fiber 21.21'.

In addition, in both the above embodiments and modifications, the ideal T
Although the present invention was applied to an EMoo mode laser beam, it can also be applied to a laser beam with a donut-shaped intensity distribution such as a higher-order T E M n mode or a laser beam from an unstable resonator. Obviously, most of the power of a laser beam (
It is preferable to set the aperture diameter to allow the light to pass through (approximately 95 inches), and arrange the light detection means on a circumference larger than D.

<Effects of the Invention> As explained above, the present invention has a configuration in which at least three light detection means are disposed on the circumference at the base of the laser beam, so that the intensity distribution of the laser beam is not impaired as in the conventional case. It is possible to detect the optical axis position without tonal.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional laser beam transmission device, FIG. 2 is a schematic diagram of a laser beam transmission device according to an embodiment of the present invention, FIG. 3 is a diagram showing the intensity distribution of the laser beam, and FIG. The figures show a modification of the above embodiment, FIG. 5 shows a second embodiment, and FIG. 6 shows a modification of the second embodiment. □ 11... Laser beam 12.12'... Base 13, 13'... Hole 14.14', 22, 22'
- Laser beam detection element 21, 21'... Optical fiber agent Masuo Oiwa (and 2 others) Figure 1 Figure 2 Figure 4 Procedure amendment (Iilm) 1. Indication of the case: Japanese Patent Application No. 58-239444 2, Title of the invention: Laser beam transmission device 3, Representative Hitoshi Katayama of the person making the amendment: Section 4, Detailed description of the invention in the agent's specification α) Specification No. On page 2, line 17, replace “current collection” with “pyroelectricity.”
and correct it. (2) In the 18th line of page 2 of the specification, the phrase "elements, etc." is corrected to "elements, thermocouples, metal resistors, thermistors, etc."that's all

Claims (1)

[Claims] A laser beam transmission device characterized in that at least three or more light detection means are arranged on the circumference of a barrel at the base of a laser beam.