JPH0448502Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a device for measuring the mode (ie, energy density distribution in a laser beam) and intensity of a laser beam.

(Prior Art) When performing laser processing, the mode and intensity of the laser beam are set appropriately before use, so it is necessary to measure the mode and intensity of the laser beam. This measurement is of course performed before starting machining, but may also be performed during machining because even once set, the mode and intensity may vary due to some factors.

(Problem to be solved by the invention) Conventionally, for example, when measuring with a CO ₂ laser, an acrylic plate that is subjected to a sublimation effect by the laser beam is generally used, and the laser beam is applied to this acrylic plate. This is done by observing the pattern (burn pattern) created by the difference in the degree of elevation. That is, the mode is measured by measuring the amount of dent in the acrylic plate at multiple locations, and the strength is determined by calculation based on this data. This measurement method is described, for example, on page 326 of the Laser Handbook (edited by the Laser Society of Japan: Ohmsha).

However, in order to elevate the acrylic plate, the laser beam must continue to be applied to the acrylic plate for several seconds, so measurements during processing must be interrupted. In addition, this interruption cannot be performed frequently because it takes a considerable amount of time to set up and elevate the measuring equipment, and online continuous measurement (i.e., multiple measurements are performed continuously and data is obtained each time). There is a problem in that the measurement results are unreliable because it is no longer possible to carry out on-line processing to obtain accurate measurement results.

Furthermore, it is difficult to obtain accurate data regarding the amount of depression in the acrylic plate due to variations in the elevation conditions, and there is a problem in that the measurement results are even more unreliable. Here, the elevation conditions include the strength or direction of the air blow when taking the burn pattern, the irradiation time of the laser beam, the direction of the irradiation, and the distance from the oscillator to the position where the burn pattern is taken (this distance determines the distribution of light energy density. ), etc.

Furthermore, a pungent odor is generated due to the elevation of the acrylic plate, and this pungent odor is also quite strong, resulting in a problem of environmental deterioration.

Moreover, since the acrylic board is a consumable item,
The problem is that it also leads to increased costs.

As described above, conventional measurement causes various problems, and in view of this point, an object of the present invention is to provide a laser beam measuring device that can solve these problems.

(Means for solving problems) Therefore, the present invention has the following configuration.

That is, a drive mechanism with an encoder function added, a plane mirror that is driven to move across the laser beam by the drive mechanism, an image sensor that receives reflected light from the plane mirror, and an encoder output of the drive mechanism and the image sensor. a data processing section to which an image output is input and scans the image output according to the encoder output to obtain measurement data;

(Operation of the invention) With this configuration, measurement data is obtained from the image output at each point where the plane mirror of the laser beam traverses, based on the encoder output.

(Example) An example of the present invention will be described below based on the drawings.

FIG. 1 is a mechanical diagram of an embodiment of the present invention, FIG. 2 is a diagram showing its operation, and FIG. 3 is a block diagram of a data processing section.

First, in FIG. 1, L is a laser beam of a CO ₂ laser emitted from a laser oscillator, lo is its optical axis, and M is also a mode pattern. That is, when the optical energy density (joul/mm ² ) of the laser beam L is expressed in the Z-axis direction on the plane formed by the X-axis and Y-axis in the direction orthogonal to the optical axis lo, it is expressed in a diagram such as the mode pattern M. The device of the present invention is intended to measure the optical energy density distribution and overall intensity shown in this mode pattern M.

Reference numeral 1 denotes a base frame, and a drive mechanism 2 and a plane mirror 3 are disposed on the base frame 1, and the plane mirror 3 is driven back and forth by the drive mechanism 2 so as to cross the laser beam L. The driving speed should be as fast as possible, preferably about 0.5 seconds.

The drive mechanism 2 includes guide bars 4, 4 and a pulse motor 5.
and a gear mechanism 6, 6, and the gear mechanism 6, 6 consists of a rack 7 and a pinion 8. The guide bars 4, 4 are provided so as to sandwich the laser beam L and extend in the X-axis direction, and pass through the plane mirror 3. This plane mirror 3 is slidable on guide bars 4, 4, and is guided by these guide bars 4, 4 in the X-axis direction. A rotational drive shaft (not shown) of the pulse motor 5 is loosely inserted and penetrated through the plane mirror 3 in a direction extending in the Y-axis direction perpendicular to the guide bar 4.
The pinions 8, 8 are positioned and fixed to this rotational drive shaft on both sides of the plane mirror 3. A rack 7 is provided outside the guide bars 4, 4 and extends in the X-axis direction, and the pinion 8 meshes with this rack 7.

The plane mirror 3 has a long shape extending in the X-axis direction, and the portion through which the guide bars 4, 4 are inserted is a main body 9. This main body 9 is made of copper, which does not easily generate heat due to the wavelength of the CO ₂ laser.
Its upper surface is formed at an angle of 45° with respect to the optical axis lo. The plane mirror 3 has a band-shaped mirror surface 10 formed by gold plating on the upper surface of the main body 9, and cooling holes 11 are formed in the main body 9, as shown in FIG. has been done.
This cooling hole 11 is for cooling by passing water or air, and penetrates from one side of the main body 9 to the other side.

As shown in FIGS. 1 and 2, a box frame 12 is attached to the end of the base frame 1 facing the mirror surface 10, and an image sensor 14 is attached to the ceiling plate 13 of this box frame 12. It is worn. This image sensor 14 receives the reflected light from the plane mirror 3, and has a licensor configuration.
2048 image sensors 15, 15... are arranged in the Y-axis direction.

A convex mirror 17 is attached to the bottom plate 16 of the box frame 12, and this convex mirror 17 has the function of weakening the reflected light from the plane mirror 3 and projecting the light onto the image sensor 14. A mirror surface 18 is provided. As shown in FIG. 2, the light reflected from the mirror surface 10 of the plane mirror 3 is
8 , is diffused by this mirror surface 18 , and a part of the light is received by the image sensor 14 . Note that a slit diaphragm may be provided in front of the image sensor 14 if necessary.

In FIG. 3, 19 is a controller, and 20 is a pulse motor driver, and these controller 19 and pulse motor driver 20 constitute a part of the drive mechanism 2. The controller 19 outputs a drive command signal having pulses according to the rotation angle or direction to the pulse motor driver 20, and the pulse motor driver 20 is turned on by the pulses of this drive command signal and performs current amplification, etc. and supplies a drive current to the pulse motor 5.

21 is a data processing section; this data processing section 21
The amplifier 22 receives the drive command signal from the controller 19 as an encoder output, receives the image output from the image sensor 14, and scans the image output according to the encoder output to obtain measurement data. and a microcomputer 23. The amplifier 22 has a built-in shift register, operates the shift register in response to an encoder output pulse from the controller 19, scans the output of the image sensor 14, and inputs the image output data to the microcomputer 23. As a result, image output data at each point can be obtained over the entire area where the laser beam L traverses the plane mirror 3. The microcomputer 23 processes the image output data at each point in real time. That is, the mode is calculated from a predetermined function Z=f(x,y) regarding the X to Z axes shown in FIG. 1, and further, the laser intensity W=∫ ^l1 _p ∫ ^l2 _p f
It is determined from the functional formula (x, y)dxdy and the measurement results are obtained. Note that this microcomputer 23 is assumed to be in charge of controlling the controller 19 here. This microcomputer 23 has
A Y-blotter 24, a CRT display 25, etc. are connected, and the measurement results are displayed on the X-Y blotter 2.
4 or CRT display 2
Displayed by 5.

(Effects of the invention) As is clear from what has been described above, the invention provides the following effects.

To obtain measurement data, you only need to pass the laser beam across the plane mirror; in other words, there is no need to keep shining the laser beam on the plane mirror, and the settings can be set in advance, making this possible even when measuring during processing. There is no need to interrupt the process, and continuous online measurement is possible.
The reliability of measurement results is improved.

Unlike the method using an acrylic plate, the object to which the laser beam is irradiated is not different each time the measurement is performed, but is always the same plane mirror, which further improves the reliability of the measurement results.

Since no irritating odor is generated, the measurement does not cause environmental deterioration.

There are no consumables that are consumed each time a measurement is performed, which is effective in reducing costs.

[Brief explanation of drawings]

FIG. 1 is a mechanical diagram of an embodiment of the present invention, FIG. 2 is a diagram showing its operation, and FIG. 3 is a block diagram of a data processing section. 2... Drive mechanism, 3... Plane mirror, 14... Image sensor, 21... Data processing section.

Claims (1)

[Claims for Utility Model Registration] A drive mechanism with an encoder function; a plane mirror that is driven to move across a laser beam by the drive mechanism; an image sensor that receives reflected light from the plane mirror; A laser beam measuring device comprising: a data processing section to which an encoder output and an image output of the image sensor are input and scan the image output according to the encoder output to obtain measurement data.