JPH04282414A - Laser beam position and angle control device - Google Patents

Abstract

PURPOSE:To enable a laser beam to be stabilized regardless of thermal deformation of laser, etc., and analysis, design, etc., to be eased by simplifying a control system by separating a position control and an angle control of laser beam. CONSTITUTION:Two mutually parallel plane mirrors 21 and 22 are provided at a beam position adjuster PM which receives a laser beam L from a beam angle adjuster M which corrects a deviation of an angle of a laser beam L and then the beam angle adjuster M and the beam position adjuster PM are controlled individually so that the position deviation can be corrected while no deviation components of angle are included by this beam position adjuster PM.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam position and angle control device applied to a measuring device using a laser beam as a reference for position measurement of a moving object.

0002

2. Description of the Related Art Generally, in a measuring device using a laser beam, the position of the laser beam tends to become unstable due to thermal deformation due to heat generated by the laser itself. As a countermeasure against this problem, the traveling direction of the laser beam emitted from the laser is corrected. A conventional laser beam position and angle control device related to this is known as shown in FIG.

In FIG. 4, 1 is a laser that emits a laser beam L, 2 is a plane mirror that reflects the laser beam L in a predetermined direction, and 3 and 4 are piezo actuators for adjusting the deflection angle of the laser beam. 2 constitute a beam angle adjuster M1. 5 is a plane mirror that reflects the laser beam L reflected by the reflecting mirror 2;
6 and 7 are piezo actuators for adjusting the laser beam position, and together with the above-mentioned plane mirror 5, the beam position adjuster M2
It consists of 8 and 9 are beam splitters. 1
Reference numerals 0 and 11 are a convex lens and a four-part light receiving element corresponding to the beam splitter 10, respectively, and the angle sensor 1 detects the deflection angle of the laser beam L by both 10 and 11.
2. Reference numeral 13 denotes a four-division light receiving element corresponding to the beam splitter 9, and constitutes a position sensor that detects the amount of beam position deviation. 14 is a controller that controls the angle adjuster M1 according to the output of the angle sensor 12;
5 is a beam position adjuster M according to the output of the position sensor 13;
This is a controller that controls 2.

Next, the operation of the above conventional configuration will be explained. A laser beam L emitted from a laser 1 is reflected by plane mirrors 2 and 5, and then split by beam splitters 8 and 9, and the beam position is monitored. The deflection angle of the laser beam L is detected by an angle sensor 12 consisting of a convex lens 10 and a four-part light receiving element 11. The detection signal is processed by the controller 14, and the feedback amount is sent to the piezo actuators 3 and 4 to control the attitude of the plane mirror 2, thereby making the deflection angle of the laser beam L zero.

Similarly, the signal detected by the position sensor 13 is processed by the controller 15, and the feedback amount is sent to the piezo actuators 6 and 7 to control the attitude of the plane mirror 5, thereby controlling the position deviation of the laser beam L. The amount is reduced to zero.

The reason why two sets of actuators 3, 4 and 6, 7 are used for the plane mirrors 2, 5 is to perform two-dimensional control in a plane perpendicular to the laser beam direction. It is. In other words, in this control system,
The positional deviation amount (x, y) and deflection angle (θx
, θy) as disturbance inputs, a stable laser beam is supplied to the output side.

The above control system is shown in FIG. In this case, since it is constant value control aimed at maintaining the position of the laser beam L, the set value is the coordinate value of the laser beam emission position Q in FIG. 4 (if Q is taken as the origin, this is (0, 0)). ) and the direction cosine (0,0,1). Here, disturbance (△
x, △y, △θx, △θy), a stable beam output is obtained by passing through the angle and position adjusters M1 and M2.

[0008]

The conventional device is constructed as described above, and the angle sensor 12 and the position sensor 13 are connected to the plane mirror 2 of the beam angle adjuster M1 and the plane mirror 5 of the beam position adjuster M2. Since the output affected by this is detected, the feedback loop of the beam position adjuster M2 becomes a minor loop. Control systems with such minor loops require special consideration in analyzing control characteristics and designing the control system.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a laser beam position and angle control device that can obtain a stable laser beam, simplify the control system, and facilitate analysis. With the goal.

0010

[Means for Solving the Problems] In order to achieve the above object, the present invention has a plane mirror that reflects a laser beam from a laser in a predetermined direction, and has a beam angle that is adjustable in the normal direction of the plane mirror. A beam angle adjustment device that has an adjuster and two mutually parallel plane mirrors that emit the laser beam reflected by the plane mirror of the beam angle adjuster in a predetermined direction, and that the normal direction of the plane mirror can be adjusted. an angle sensor that has a collimating lens and a 4-split photodetector and detects the laser beam angle; a position sensor that includes the 4-split photodetector and detects the position of the laser beam; and a controller that separately controls the position.

[0011]

[Operation] According to the present invention having the above structure, the beam angle adjuster and the beam position adjuster can correct the deviation in the position and angle of the laser beam. By providing a plane mirror, the movement of the beam position adjuster does not affect the adjustment of the beam angle, and the control system for the position and angle of the laser beam becomes an independent loop, making analysis etc. easier.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a laser beam position and angle control device according to an embodiment of the present invention, and the same parts as in the conventional one are given the same reference numerals and their explanation will be omitted. .

In FIG. 1, 21 and 22 are two plane mirrors that are arranged parallel to each other and output to the beam splitter 8 side that reflects the laser beam from the plane mirror 2, and are arranged so that their relative positions do not change. It is firmly fixed to the frame 23. 24 and 25 are actuators for the pedestal 23, and together with the plane mirrors 21 and 22, etc., constitute a beam position adjuster PM.

The beam position adjuster PM has, for example, elastic hinge mechanisms 26 and 27 as shown in FIG. Laser beam L
The elastic hinge mechanism 27
The actuator 25 applies a rotational displacement about the vertical axis to the pedestal 23 to correct the displacement of the laser beam L in the horizontal direction.

Reference numeral 28 denotes a collimating lens, whose focal plane and focal point coincide with the light receiving surface and light receiving center point of the 4-split light receiving element 11, respectively, and both 11 and 28 constitute the angle sensor 14. . Note that one controller 14 includes a control circuit (not shown) that processes the angular deviation amounts θx and θy detected by the angle sensor 12 to determine a control amount, and a beam angle adjuster M that amplifies the control signal. It includes a drive circuit (not shown) for driving the . The other controller 15 includes a control circuit (not shown) that processes the positional deviation amounts x and y detected by the position sensor 13 to determine a control amount, and a beam position adjuster that amplifies the control signal. It includes a drive circuit (not shown) that drives the PM.

Next, the operation of the above configuration will be explained. A laser beam L emitted from a laser 1 is reflected by a plane mirror 2 and outputted via two parallel plane mirrors 21 and 22 and beam splitters 8 and 9. At this time, the deviation angles θx and θy (FIG. 6) of the laser beam L are detected by the beam angle sensor 12, and the positional deviation x of the laser beam L is detected by the beam angle sensor 12.
, y are detected by the position sensor 13, as in the conventional case.

It should be noted here that the positional deviations x and y detected by the position sensor 13 include both components from the beam angle deflection and the beam parallel deviation, and these must be separated. Therefore, the beam position adjuster PM must be moved to make this amount zero. However, the movement of the beam position adjuster PM does not affect the angular deflection of the laser beam L, and as a result, the movement of the beam position adjuster PM does not affect the angular deflection of the laser beam L.
M moves so that only the beam parallel deviation component after the beam angle deflection component is removed by the beam angle adjuster M becomes zero, and the two control systems can be separated.

This control system is shown in FIG. In this control system, beam position and angle disturbances △x, △y,
△θx, △θy are input, and first the angle disturbance △θ is detected in a feedback loop between the beam angle adjuster M and the angle sensor 14.
x, Δθy (FIG. 4) are controlled, and then position disturbances Δx, Δy are controlled by a feedback loop between the beam position adjuster PM and the position sensor 15. In this way, both feedback loops can be separated, and as a result, analysis of the control system, etc. can be easily performed.

[0019]

As described above, according to the present invention, the deflection angle and the deflection position of the laser beam can be corrected by the beam angle adjuster and the beam position adjuster, and the laser beam can be stabilized. By attaching two mutually parallel plane mirrors to the beam position adjuster, it is possible to separate the position control and angle control of the laser beam from each other, simplifying the control system and facilitating analysis and design. Produce an effect that can contribute.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a laser beam attitude and angle control device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a beam position adjuster.

FIG. 3 is a block diagram showing a control system of the laser beam attitude and angle control device of the present invention.

FIG. 4 is a configuration diagram showing a conventional laser beam attitude and angle control device.

FIG. 5 is a block diagram showing a control system of a conventional laser beam attitude and angle control device.

FIG. 6 is a conceptual diagram showing the amount of deviation of a laser beam.

[Explanation of symbols]

1 Laser 2, 21, 22 Plane mirror 12 Angle sensor 13 Position sensor 14,15 Controller L Laser beam M Beam angle adjuster PM beam position adjuster

Claims (1)

[Claims] 1. A beam angle adjuster comprising a plane mirror that reflects a laser beam from a laser in a predetermined direction, and a beam angle adjuster capable of adjusting the normal direction of the plane mirror; a beam angle adjuster having two plane mirrors parallel to each other that emit a laser beam in a predetermined direction, and capable of adjusting the normal direction of the plane mirrors;
An angle sensor that has a collimating lens and a 4-split light receiving element and detects the laser beam angle; a position sensor that has a 4-segment light receiving element that detects the position of the laser beam; and a position sensor that detects the laser beam angle and position. A laser beam position and angle control device comprising: a controller for controlling the position and angle of a laser beam separately;