WO2008001808A1

WO2008001808A1 - Laser machining apparatus

Info

Publication number: WO2008001808A1
Application number: PCT/JP2007/062903
Authority: WO
Inventors: Shinji Watanabe; Yoshio Matsuda; Hiroki Yamashita
Original assignee: O.M.C Co., Ltd.
Priority date: 2006-06-30
Filing date: 2007-06-27
Publication date: 2008-01-03
Also published as: KR20090030254A; CN101426611A; JPWO2008001808A1; JP4852098B2; KR101376995B1; CN101426611B

Abstract

Detection of the three-dimensional shape of a work, enhancement of the precision of the focal point position of a machining laser beam, and compaction of a laser beam machining apparatus are realized. The laser beam machining apparatus (10) operates as follows. While a laser beam output section driver (46) is moving a work (12) from a position near a laser beam output section (22) to a far position, the work (12) is sequentially imaged with a camera (34). Best focused point detection data is extracted from pixels in positions corresponding to best focused point detection positions (P1-n) predetermined in the captured images. A best focused point detection waveform (W) based on the variation of the best focused point detection data is formed for each best focused point detection position (P1-n). The peak values (PK) of the best focused detection waveforms (W) in the best focused detection positions (P1-n) determined from the best focused detection waveforms (W) are compared with one another so as to judge the acceptance/rejection of the work (12). If the work is acceptable, the laser beam output section (22) is moved to the best focused position to perform laser beam machining; contrarily if the work is rejected, the laser beam is not emitted.

Description

Specification

Laser processing equipment

Technical field

[0001] The present invention is capable of detecting a three-dimensional defective product of a work piece which can not be detected by the conventional apparatus and this three-dimensional shape inspection at a laser processing position, and at the time of laser processing The present invention relates to a laser processing apparatus capable of focusing the laser at the processing position with high precision.

Background art

[0002] A conventional force is also used to evaporate and remove or weld a workpiece by emitting a laser to the workpiece. According to this laser cover, by focusing the laser having the largest energy density to the processing position of the workpiece, the workpiece at the processing position is removed by evaporation or melted to cut the hole of the workpiece. It can be opened or welded, and at present, such laser technology is widely used for manufacturing semiconductor devices and other electronic parts.

[0003] By the way, with recent technological progress, semiconductor devices and other electronic components have been steadily miniaturized and becoming highly accurate, and higher processing accuracy is required also for laser technology. In order to meet this demand, for example, a “harmonic laser” that is more suitable for laser beam scanning than YAG laser, instead of the typical YAG (lithium 'aluminum' garnet) laser used as a laser. Is supposed to use. However, such “harmonic laser” is more accurate than before when using “harmonic laser” whose depth of focus is much shallower than that of conventional YAG lasers. Depending on the accuracy of accurate focusing, the product yield will be greatly affected.

At the same time, along with the miniaturization and high precision of electronic parts, the shape and quality of the component to be incorporated are also strictly asked, and recently, the quality and shape of the three-dimensional shape has also been considered as a problem. In other words, it is required that parts with shapes that were considered to be non-defective products be removed strictly before laser processing. Therefore, high machining accuracy is required, and at the same time the ability to detect three-dimensional defect shape of the workpiece to which laser calorie treatment is applied It is the present condition that is required.

A conventional method is a method using a force CCD camera generally introduced for shape inspection of objects to be removed. That is, the image of the reference shape of the workpiece (= reference image) is stored, the workpiece to be sequentially sent is imaged by the CCD camera, this image (= captured image) is compared, and the imaged image and the reference image In the case where it is determined that there is a failure, it is judged as a non-defective product, and when the captured image is different from the reference image, it is removed as a defective product (Patent Document 1). While the method of using a CCD camera is effective in determining the quality of the planar shape, the three-dimensional shape determination of a three-dimensional member such as that incorporated in an electronic component, and the fine focus of the laser beam device It is unsuitable for the match. Therefore, an invention was proposed in which the shape of a three-dimensional object was inspected by tilting the CCD camera with respect to the object to be processed, but it was impossible to apply to a three-dimensional object as in the present invention. It was a good idea to apply it to laser focusing.

Patent Document 1: Japanese Patent Application Laid-Open No. 4-208844

Patent Document 2: Japanese Patent Application Laid-Open No. 10-185827

Patent Document 3: Japanese Patent Application Laid-Open No. 11-230728

Patent Document 4: Japanese Patent Application Laid-Open No. 11-326235

Patent document 5: Unexamined-Japanese-Patent No. 2000-171409

[0006] In addition, generally, the shape of the workpiece is judged before the processing department, the defective product is removed, and only the non-defective product is supplied to the processing department. In this case, one laser cae machine will have a defect judgment department and a kaw department arranged side by side, and there is a drawback that the equipment shape becomes large. In addition, there is a problem that the position of the workpiece is deviated, and the compactness of the apparatus is also required to improve the quality judgment and the processing performance.

Disclosure of the invention

Problem that invention tries to solve

The present invention has been made in view of the pressing problem, and its main object is to detect a workpiece having a defective shape which can not be detected conventionally, and to focus a processing laser. Provide laser processing equipment that achieves higher accuracy and compactness of equipment It is to offer.

Means to solve the problem

The invention described in claim 1 is

(a) A laser 10 for emitting a processing laser X to a processing position of a load receiving object 12 and processing the load receiving object 12;

(b) Processing laser generator 14 for generating processing laser X

(c) an illumination device 16 for emitting illumination light Y for illuminating the workpiece 12;

(d) A laser emitting unit 22, which is optically connected to the processing laser generator 14 and the illumination device 16, and emits the processing laser X and the illumination light Y toward the workpiece 12.

(e) A laser emitting unit driver 46 for moving the laser emitting unit 22 close to and away from the workpiece 12;

(f) The laser emitting part drive unit 46 moves the laser emitting part 22 in the approaching and separating direction with respect to the workpiece 12 so that the distance between the laser emitting part 22 and the workpiece 12 is different. Camera 34 for sequentially imaging the workpiece 12 illuminated by the illumination light Y,

(g) In a plurality of images sequentially captured at different imaging positions, a plurality of in-focus detection positions P in a screen preset to be used for shape detection of the workpiece 12

The in-focus detection data detected at the pixel corresponding to 1-n is sequentially extracted, and the in-focus detection waveform W based on the change in the in-focus detection data is formed for each in-focus detection position P.

1-n

Each focusing at each focusing point detection position P determined from each focusing point detection waveform W

1-n

Compare the peak value PK of the point detection waveform W,

(g-1) When all of the peak values PK are within a predetermined range (= threshold value), the workpiece 12 is judged as good and the combination of the laser emission part 22 with the workpiece 12 is determined. The laser emitting unit 22 is moved to the in-focus position Xp, and after that, the laser emitting unit 22 is operated to direct the laser source 12 to perform a laser power by laser emitting.

(g-2) If the peak value 1 deviates from the predetermined range, the laser emitting unit 22 is instructed to determine that the workpiece 12 is a defective product and to prevent laser emission. An image processing apparatus 44 for

(h) Laser processing apparatus 10 According to the present invention, since the quality of the three-dimensional shape of the object 12 to be driven is judged immediately before the laser processing in the laser cavity section, the shape determination section and the processing section differ from each other as in the conventional example. As well as being able to prevent the positional deviation of the load-bearing object 12 which has been generated due to the fact that both sections can be integrated into one, it is possible to realize the compactness of the device.

Also, the peak value PK of each in-focus detection waveform W at each in-focus detection position P is used.

1-n

By doing this, the laser emission unit 22 can be set to the correct in-focus position Xp, and the accuracy of focusing of the laser for calories can be further enhanced. In other words, it is possible to cope with fine focusing of two or three or more higher harmonic lasers.

In addition, the peak value PK of each in-focus detection waveform W at each in-focus detection position P is compared

1-n

By comparison, the three-dimensional shape of the workpiece 12 can be easily determined prior to laser processing at the laser processing position, and the threshold is limited to a minute range near the peak value PK as described later. This makes it possible to cope with the focusing of the higher harmonics.

Here, “focus detection data” refers to the brightness of the pixel (or a plurality of pixel groups adjacent or close to each other) for detecting each minute part of the image captured by the camera 34. Raw data obtained by extracting and processing data such as color saturation, etc., or their average value (= arithmetic mean value of multiple raw data at the same point obtained by the vertical movement of the camera 34), standard deviation, Although the difference between the minimum value and the maximum value, the maximum value, and the like are mentioned, in the present embodiment, one raw data is adopted, and the following description will be made based on this case. Of course, even if it is based on processed data, such as average value, standard deviation, difference between minimum value and maximum value, and maximum value, it is the same.

Further, the “focused position Xp” of the laser emission unit 22 with respect to the workpiece 12 is the peak value of the all focusing points detection position P, or the arithmetic mean value of the PK group or PK (usually

1-n

Corresponds to a value calculated by any peak value PK) or other calculation method closest to the average value.

The invention described in claim 2 is an in-focus point detection position P 1S for image processing.

1-n

(a) Center of driven object 12 and five points at each corner (P-1) (P-3) (P-5) (P-7) (P-9),

(b) Each corner of the workpiece 12 and eight points (P-1) to (P-8) on each side, (c) Each corner of the driven object 12 and each side and nine points (P-1) to (P-9) or

(d) The laser according to claim 1, characterized in that it is an arbitrary point on the plane of the force receiving object 12 added to the nine points (P-1) to (P-9). It is the processing apparatus 10, and by measuring these points, it is possible to measure the shape of a three-dimensional shape, in particular, a wedge or!

[0015] Claim 3 relates to a processing laser used in the present invention, characterized in that "the processing laser is a second or higher harmonic of higher order", whereby high processing accuracy is achieved. Is obtained. The use of the measurement method according to claim 1 or claim 2 makes it possible to use a second or higher harmonics laser.

Effect of the invention

According to the present invention, by setting the in-focus point detection position of image processing to a large number of points P, a point to be scanned is generated.

1-n

It is possible to judge the presence or absence of objects and the quality of workpieces of three-dimensional shape, and in particular, by setting the number of points to 5 or more, it is possible to judge the quality of three-dimensional defect shape having warping and bending that can not be judged conventionally. . This determination can also be made by the laser processing department immediately before the laser processing, so that it is possible to achieve compactness of the laser cover device, and it is possible to detect the defective shape from the location where the laser processing is performed. It has the advantage of eliminating the need to correct the position of the misaligned workpiece during transport to the end. By using the peak value PK of each in-focus detection waveform W at each in-focus point detection position P,

1-n

The accuracy of the focus forming position of the processing laser can be made high enough to endure the use of high-order processing lasers such as the second and third harmonics.

Brief description of the drawings

FIG. 1 is a conceptual view showing a laser processing apparatus according to the present invention.

FIG. 2 is a conceptual view showing a processing laser generator.

FIG. 3 is a conceptual view showing a laser emission unit according to the present invention.

FIG. 4 is a view showing eight in-focus detection positions on a non-defective workpiece.

FIG. 5 is a diagram showing a representative waveform based on the feature value at the in-focus point detection position.

FIG. 6 is a diagram showing waveforms at each in-focus point detection position on a non-defective workpiece.

[Fig. 7] A diagram showing the waveforms at each focus detection position in the absence of a workpiece is there.

[Figure 1-

o 8] It is a figure which shows the waveform in each focus detection position in the workpiece of a defect shape. Garden 9] It is a figure which shows the waveform in each in-focus detection position in the workpiece of a defect shape.

FIG. 10 is a view showing a waveform at each focus detection position on a workpiece having a defect shape.

FIG. 11 is a block diagram showing each step of a laser beam method according to the present invention.

Explanation of sign

· · Laser equipment

11 · "Mount

12 · · · Workpiece

14 · · · Laser generator for processing

16 · · · Lighting system

18 · · · Laser system

20 ··· Fiber

21 · "Fiber

22 · · · Laser output part

23 · · · Laser emission position adjustment means

25 · Tubular body

26 · · · Condenser

28 · '· Laser semi-reflecting mirror for processing

30 · Illumination light semi-reflecting mirror

32 · '· Focusing lens for camera

34 · "Camera

36 · '-Exit

38 · '' Camera connection port

40 ······· Laser beam for processing

42 · · • Illumination light exit

44 · · 'Image processing device

46 · '' Laser emitter drive 100 ·· Laser chamber

102 · · · Resonator mirror

104 · · · Resonator shutter

106 ... Power measurement unit

108 ... bifurcated mirror

110: Branch shutter

112 ··· Power adjustment unit

114 ··· Optical fiber injection unit

116 ... Helium neon laser oscillator

118 ... folding mirror

BEST MODE FOR CARRYING OUT THE INVENTION

The laser cover apparatus 10 according to the present invention is, as shown in FIG. 1, a three-dimensional workpiece 12 (in this case, a rectangular parallelepiped) which is an electronic component constituting member such as a tantalum capacitor mounted on a mount 11. Or a cube) is a device that performs processing such as emitting a processing laser X to weld a three-dimensional force receiving object 12 to the mount 11 or the like, the processing laser generator 14 and the lighting device 1 6 And a laser emitting device 18. The laser emitting device 18 is a device for emitting the processing laser X and the illumination light Y toward the object 12 or emitting the light, and as shown in FIG. And laser emitting portion position adjusting means 23.

The processing laser generator 14 is a device for generating the processing laser X, and in this embodiment, it is used for generating the second harmonic YAG laser (or higher harmonics are also possible). It is necessary. The processing laser generator 14 further includes an optical fiber 20, and the processing laser X is guided to the laser emission unit 22 by the optical fiber 20. The processing laser X generated by the processing laser generator 14 is not limited to the second harmonic YAG laser, and a laser having a wavelength according to the physical properties of the object 12 to be treated and the content of the laser is selected. I can do it.

More specifically, with respect to the processing laser generator 14, as shown in FIG. 2, the processing laser generator 14 faces the laser chamber 100 and the laser chamber 100 at predetermined intervals on both sides of the laser chamber 100. Pair of resonator mirrors 102, and a pair of resonator mirrors provided on an optical path connecting the resonator mirror 102 and the laser chamber 100. A resonator shutter 104, a power measurement unit 106, a branch mirror 108, a branch shutter 110, a power adjustment unit 112, an optical fiber incident unit 114, and a helium neon laser oscillator 116 that oscillates a visible light laser Z. I have it.

The laser chamber 100 is internally provided with a flash lamp (not shown) and a YAG rod (not shown), and by emitting light from the flash lamp, the YAG rod is excited to emit light energy. Be done.

The pair of resonator mirrors 102 is a device that reflects light energy emitted from the laser chamber 100 and causes the resonator mirrors 102 to reciprocate in order to oscillate the processing laser X. The distance at which the pair of resonator mirrors 102 is installed is appropriately set in accordance with the wavelength of the processing laser X that oscillates.

The pair of resonator shutters 104 is a device for opening and closing an optical path connecting the resonator mirror 102 and the laser chamber 100. The resonator shutter 104 is closed until the energy in the laser chamber 100 is sufficiently stored, and after a predetermined time has elapsed, the resonator shutter 104 is opened and the processing laser X is oscillated to increase the height. A strong processing laser X can be obtained.

The first measurement unit 106 is a device for measuring the intensity of the processing laser X, and in the present embodiment, the optical path connecting the resonator mirror 102 and the laser chamber 100 is the laser chamber 100 force in FIG. It is disposed at a position extended in the direction away from.

The laser X for laser light oscillated from the laser chamber 100 is reflected by the branch mirror 108 provided on the optical path, passes through the branch shutter 110 and the power adjustment unit 112, and is transmitted to the optical fiber incident unit 114. be introduced. Then, the laser X introduced into the optical fiber incident unit 114 is collected and introduced into the optical fiber 20.

In the case where the laser X generated by one laser chamber 100 is supplied to a plurality of laser irradiation devices 18, as shown by a broken line in FIG. 2, the branch mirror 108 and the branch shutter 110. A plurality of power adjustment units 112 and a plurality of optical fiber injection units 114 are provided. At this time, in order to branch the processing laser X toward the corresponding optical fibers 20, a semi-reflecting mirror (also referred to as a half mirror) is used as the branching mirror 108. In addition, in the power adjustment unit 112, each of the branched processing lasers X By adjusting the intensity, the intensity of each processing laser X becomes uniform. Furthermore, the optical fiber 20 into which the processing laser X is introduced can be appropriately selected by opening and closing the branch shutter 110 as necessary.

In addition, after the visible light laser Z oscillated from the helium neon laser oscillator 116 is reflected by the folding mirror 118, the helium neon laser oscillator 116 and the folding mirror are made to pass along the same optical path as the processing laser X. The position of 118 is adjusted. As a result, the visible light laser Z can be used as a guide light for adjustment of oscillation of the processing laser X, adjustment of incidence, and the like.

The illumination device 16 is a device for emitting illumination light Y which is a visible light used for focusing the laser emission unit 22 on the workpiece 12 as shown in FIG. 1, and in the present embodiment, LED is used. The lighting device 16 can also use another light emitting device such as a halogen lamp. The illumination device 16 further includes an optical fiber 21, and the illumination light Y is guided to the laser emission unit 22 by the optical fiber 21. In the present embodiment, the processing laser X and the illumination light Y are guided to the laser emitting device 18 using the optical fibers 20 and 21. However, as a matter of course, these may be realized by a fixed optical system.

As shown in FIG. 3, the laser emitting unit 22 includes a tubular body 25, an objective lens system 26, a processing laser semi-reflecting mirror 28, an illumination light semi-reflecting mirror 30, and a condenser for a camera. A lens system 32 and a camera 34 are provided.

The tubular body 25 has at one end an emission port 36 which is an opening for emitting the processing laser X and the illumination light Y, and at the other end a camera 34 reflects the reflected light of the illumination light Y by the workpiece 12. Is a circular cross section pipe having a camera connection port 38 which is an opening for leading to the Further, on the side surface of the tubular body 25, a processing laser inlet 40 to which the optical fiber 20 is connected and an illumination light inlet 42 to which the optical fiber 21 is connected are provided.

The objective lens system 26 is a lens system combining a convex lens, a concave lens, and the like that forms the focal point of the laser X for a laser beam at a predetermined position from the laser emission device 18, and is mounted at an emission port 36. .

The processing laser semi-reflecting mirror 28 is a plate-like semi-reflecting mirror having a property of reflecting the processing laser X on the surface and passing the reflected light of the illumination light Y emitted to the object 12 It is one. Also, the processing laser semi-reflecting mirror 28 is positioned at the processing laser exit 40 so that the laser X incident from the processing laser exit 40 can be reflected toward the exit 36. Are fixed at a predetermined angle (for example 45 °) in relation to the position of the outlet 36 or are disposed inside the tubular body 25 as adjustable.

The illumination light semi-reflecting mirror 30 is a plate-like semi-reflecting mirror that reflects the illumination light Y on its surface and passes the reflected light of the illumination light Y. Then, the illumination light semi-reflecting mirror 30 directs the light axis R of the light guide path of the illumination light Y incident from the illumination light emission port 42 to the emission port 36 so as to coincide with the optical axis of the processing laser X. In order to be able to reflect, it is fixed at a predetermined angle (for example 45 °) in relation to the position of the illumination light outlet 42 and the position of the outlet 36 or V is arranged inside the tubular body 25 as adjustable. It is.

The condenser lens system 32 for a camera is a lens system that condenses the reflected light of the illumination light Y reflected by the workpiece 12 on the camera 34, and is attached to the camera connection port 38.

As shown in FIG. 1, the laser emitting unit position adjusting means 23 includes an image processing unit 44, a laser emitting unit driving unit 46, a camera 34, an image processing unit 44 and a laser emitting unit driving unit 46. And a circuit 48 for electrically connecting, and the laser emitting unit driving device 46 is an image of the workpiece 12 illuminated with the illumination light Y within a preset movement range of the laser emitting unit 22. The distance between the laser emitting portion 22 and the workpiece 12 is different (ie, movement of the laser emitting portion 22 relative to the workpiece 12 in the approaching or separating direction (= proximity or separation only or one or several reciprocation movements) Among the above, it is a means to make the laser emitting part 22 approach and separate in the vertical direction with respect to the workpiece 12 within the above-mentioned range in order to perform multiple imaging with the camera 34 at each imaging position T determined in small increments. And for processing to emit processing laser X A means for moving the laser emitting section 22 to over The exit correct position (focus position Xp).

The camera 34 is closely spaced with respect to the processing object 12 together with the laser emitting unit 22 within the range previously set by the laser emitting unit driving device 46 and is illuminated by the illumination light Y. This is an apparatus for imaging a plurality of images of the workpiece 12 in the above-described state in which the distances between the laser emission unit 22 and the workpiece 12 are different from each other. The image captured by the camera 34 and output to the image processing device 44 of the laser emission position adjustment means 23 is composed of hundreds of thousands of pixels and millions of pixels. It is done. Then, these pixels are described as the value of the luminance (= light and shade) of the pixel (hereinafter, referred to as “tone”. For example, when the pixel is composed of 8-bit information, it has 256 tones. )have. In the present embodiment, a CCD camera 34 is used.

The image processing device 44 performs the following operation. First, at each imaging position during movement of the laser emitting unit 22, a force to which an image captured by the camera 34 is sequentially sent is preset to be used for detecting a three-dimensional shape of the object 12 in this image. Focus detection positions P in the selected screen

The in-focus point detection data detected at the pixel at the position corresponding to 1-n is sequentially taken out and stored. Then, an in-focus detection waveform W based on a change in the in-focus detection data is formed for each in-focus detection position P, and each in-focus detection waveform W

1-n

Peak value PK of each in-focus point detection waveform W at each in-focus point detection position P

1-n

Compare When all the peak values PK are within a predetermined range (= threshold value), the workpiece 12 is determined as a non-defective product, and the laser emitting unit driver 46 determines the laser emitting unit 22 for the workpiece. An instruction to move the laser emitting unit 22 to the in-focus position Xp is issued to the laser emitting unit driving device 46. After that, a command for causing laser processing by laser emission toward the workpiece is issued to the laser emission unit 22.

Conversely, when 1 of the peak value also deviates from the predetermined range (= threshold value) force, the laser emission is commanded to determine that the workpiece is defective and not to perform laser emission. Output to section 22. In the present embodiment, a general-purpose personal computer is used for the image processing device 44 in order to execute the above-mentioned work.

When it is determined that the workpiece 12 is a non-defective product and the laser emission unit 22 is moved to the in-focus position Xp of the laser emission unit 22 with respect to the workpiece by the laser emission unit driving device 46, the peak value There are as many PK as the number of focus detection positions P. Therefore, the laser emitting unit

1-n

The in-focus position Xp for the workpiece 12 to be moved by 22 is obtained by the arithmetic average of the peak value PK group or the peak value PK closest to the average value among them, or other suitable means. Will be adopted.

Next, the image processing performed by the image processing device 44 will be described in detail. When the workpiece 12 (non-defective product) is imaged by a camera, there is a high possibility that the non-defective three-dimensional shape of the workpiece 12 can be detected. ~ 8) If you set This will be described using FIG. Of course, the invention is not limited to this, and the in-focus point detection position P is plural

There are 1-n, which are more than 5 in practical use.

[0042] For each of the images captured by the camera 34 (images at the moving image capturing position in motion within the movement range; the status is shown in FIGS. 5 (a) to 5 (c)). Focus detection data for pixels at eight focus detection positions (P-1 to 8) (or a group of pixels including pixels in the vicinity; in this specification, simply referred to as "pixels" unless necessary. Are sequentially stored, and the in-focus point detection data of the other part of the pixel is discarded. When the accumulation of focus detection data of pixels at the focus detection positions (P-1 to 8) for all images is completed, next, for each focus detection position (P-1 to 8), The amount of change is plotted to draw the in-focus detection waveform W.

That is, the in-focus point detection data (in the case of the present invention, the brightness or gray level) of each pixel at each in-focus point detection position (P-1 to 8) is picked up by the camera 34 (ie, the mount 11). The in-focus detection waveform W is obtained by plotting on the graph in the order of near position force and far position). A case of obtaining the in-focus point detection waveform W at the in-focus point detection position (P-1) will be described as a specific example with reference to FIG.

The two-dot chain line in FIG. 5 indicates the position of the laser emission unit 22 when the workpiece 34 is imaged by the camera 34 during the movement of the camera 34 (= continuous movement or movement while stopping during photographing). Varies from moment to moment! /, Indicates an imaging position T.

In the present embodiment, the luminance of the pixel at the intersection of the imaging position T (two-dot chain line in FIG. 5) and the in-focus point detection position (P-1) is recorded as in-focus point detection data. As the focal point of the laser emitting unit 22 is closer to the corner C of the object 12 to be focused, the luminance (or gray level) detected by the pixel is higher because the image is in focus.

Therefore, when these in-focus point detection data (brightness etc.) in the movement range are plotted, it is natural that the focal point of the laser emitting part 22 is the angle of the force-controlled object 12 as shown in FIG. 5 (a). An in-focus point detection waveform W is generated in which the in-focus point detection data (such as the brightness) peaks as the position (height) is closer to the part C. In other words, it can be determined that the peak value PK of the in-focus point detection waveform W is the in-focus position (height) Xp that matches the focal length of the laser emission unit 22.

In addition, as shown in FIG. 5 (b), if the corner C force is lower than that in FIG. The peak value PK of the focus detection data (brightness) will occur at a low position. Furthermore, when the workpiece 12 is not present, that is, when the in-focus position is not present, no peak value 生じ is generated as shown in FIG. 5 (c). Note that the depth of focus of the laser emission unit 22 (the range in which it is in focus) or a numerical value smaller than that (for example, 1Z2 of the depth of focus) is set as the threshold, and the height from the workpiece 12 to form the peak value ΡΚ. If the position is determined, in the case of FIG. 5 (a), the peak value が falls within the threshold range and it is judged as a non-defective product.

On the other hand, in the case of FIG. 5 (b), it can be seen that the peak value 外 is out of the threshold range, and the thickness of the workpiece 12 is out of the standard. Furthermore, in the case of FIG. 5 (c), a force whose peak value ΡΚ can not reach the threshold value is also judged to be without the object 12 to be impacted. As described above, if the case of FIG. 5A is regarded as a non-defective product, by detecting the height from the force-applying object 12 of the peak value, it is possible to judge whether the height relationship of the workpiece 12 is good or not.

With reference to such a relationship, reference is made to FIG. As shown in FIG. 6, the peak value at the same position (assuming that the height relationship is also within the non-defective range) at the in-focus detection waveform W at the in-focus detection position (Ρ 1 to 8) of the workpiece 12 In the case of exhibiting a shape having a wrinkle, it is possible to determine that the shape of the workpiece 12 is a good product free of distortion such as bending or jumping at the four corners and four sides.

If the workpiece 12 is not present in the processing area, as shown in FIG. 7, the peak of the waveform at the in-focus detection position (Ρ1 to 8) does not exceed the threshold, and the force is also not processed. The in-focus point detection data (brightness) gradually decreases as the distance from the mechanical object 12 increases, and the presence or absence of the workpiece 12 can be detected promptly by detecting the in-focus point detection data (brightness). It can.

Further, as shown in FIG. 8, when one end of the workpiece 12 is warped and located at a high position, the peak value at the focus detection position (における 1 to 3) is Ρ. The peak value における at the in-focus point detection position (Ρ5 to 7) is located on the upper side in the figure (= there is an in-focus point at a high position), and the result is obtained.

In addition, as shown in FIG. 9, when the workpiece 12 has a shape that curves downward and is convex, the peak value PK at the focus detection position (P-1 to 3, 5 to 7) is obtained. In comparison, the peak value PK at the focus detection position (P-4 and 8) is t located at the lower side in the figure, and the result is obtained to know the warp condition of the workpiece 12 in the 8-point measurement. I can do it. However, processed Since the center of the object 12 is not measured, it is impossible to detect that the force object 12 is distorted like a bowl or a downward bowl.

Furthermore, as shown in FIG. 10, when the workpiece 12 is warped upward and convex, as compared with the peak value PK at the in-focus detection position (P-1 to 3, 5 to 7), When the peak position at the in-focus point detection position (P-4 and 8) is located on the upper side in the figure, the result is obtained.

In the present embodiment, the in-focus position P is detected at eight corners of the workpiece 12 and eight sides.

1-n

Although it was set, if at least five points at the center and each corner of the workpiece 12 are measured, it can be understood that it is warped or wrinkled or distorted downward. Further, more accurate measurement is possible by measuring each corner of the workpiece 12, each side and nine points in the center. Furthermore, if an arbitrary point on the plane of the workpiece 12 is further measured in addition to the nine points, defects on the plane of the workpiece 12 can be detected. That is, in the in-focus point detection position P

As the 1-n number is larger, the accuracy in determining the workpiece 12 with a more or less defective shape can be enhanced.

For example, the case where nine in-focus detection positions P are set will be described with reference to FIG.

1-n

Then, by setting the ninth in-focus point detection position (P-9) in the central part of the workpiece 12, the in-focus point detection position (P-9) is the in-focus point detection position (P-4 and The same waveform as in 8) can be obtained. Therefore, when eight focus detection positions are set, it is unclear whether the central portion of the workpiece 12 of the defective shape shown in FIG. 9 is concave or not. Again, by setting nine focus detection positions, it can be determined that the upper surface of the workpiece 12 is highly likely to be a curved surface without irregularities.

Next, a method for covering the object 12 using the laser beam device 10 according to the present embodiment will be described based on a block diagram shown in FIG. When the method is started, the positioning of the force receiving object 12 in the XY direction (direction orthogonal to the emitting direction of the processing laser X and the illumination light Y) has already been completed.

First, illumination light Y is emitted from the illumination device 16 (illumination light emission step [S−l]). In this step, the illumination light Y emitted from the illumination device 16 is incident on the inside of the tubular body 25 from the illumination light entrance 42 through the optical fiber 21. The illumination light Y entering the inside of the tubular body 25 is reflected by the illumination light semi-reflecting mirror 30 to turn in the direction of the exit 36, and the objective lens system 26 After being refracted when passing through, it is irradiated toward the workpiece 12 and illuminates the entire surface of the workpiece 12 with uniform brightness.

Next, after moving the laser emission unit 22 to a position closest to the preset target object 12 by the laser emission unit driving device 46 and moving the laser emission unit 22 away from the workpiece 12, Move continuously or intermittently by the movement range. Along with the movement, images of the preset number of workpieces 12 are imaged by the camera 34 at different separation distances from the workpiece 12 and output to the image processing device 44 (image capturing step of workpiece images) [S-2]). In the present embodiment, the image processing apparatus 44 outputs each image taken at different separation distances from the laser emitting unit driving device 46 together with the position information of the laser emitting unit 22, and the image processing apparatus 44 Record with

Then, as described above, the image processing device 44 determines the quality of the shape of the workpiece 12 and determines the in-focus position (focused position determination step [S-3]). If it is determined that the shape is a defect, the laser processing thereafter is stopped, and the laser processing process is started from the beginning for the next object.

On the other hand, when the workpiece 12 is determined to be non-defective, the laser emitting unit 22 is driven to the position of the laser emitting unit 22 when the image corresponding to the peak value PK is taken, that is, the in-focus position. It moves with the device 46 (laser emitting part moving step [S-4]). In the present embodiment, as described above, the position information of the laser emission unit 22 for each image of the workpiece 12 is recorded in the image processing device 44, so the peak value PK of the focus detection data is obtained. The laser emission unit 22 is moved to the in-focus position based on the position information when the corresponding image is taken, but there are a plurality (five or more) of peak values PK. Alternatively, a value determined by a value near the center of the peak value PK or a value obtained by an optimal method other than that is used as the in-focus position Xp of the laser emission unit 22, and the laser emission unit 22 is moved to this position. Since all the peak values PK are within the depth of focus of the laser emitting unit 22, the focus does not get out of focus by any value, but it is preferable to use an arithmetic average value.

When the movement of the laser emission part 22 is completed, the processing laser generator 14 finally generates the processing laser X, and the light from the processing laser emission port 40 via the optical fiber 20 is used for laser processing. The first X is emitted into the inside of the tubular body 25, and the workpiece 12 is laser processed (laser cover [S-5]). In the present embodiment, the processing laser X generated from the processing laser generator 14 is guided to the optical fiber 20 and enters the inside of the tubular body 25 from the processing laser inlet 40. Then, the incident laser beam X is reflected by the laser beam semi-reflecting mirror 28 to change the direction to the direction of the emission port 36, and the beam is condensed when passing through the objective lens system 26. Emit to work piece 12. At this time, since the laser emission unit 22 is accurately moved to the in-focus position of the laser emission unit 22 in advance, the focal point of the laser X for laser light emitted to the object 12 to be driven is The workpiece 12 can be machined at a focal position where it matches with the workpiece 12 with high accuracy and the energy density of the processing laser X is maximum.

In the present embodiment, the focal position is adjusted by moving the entire laser emission unit 22 including the objective lens system 26 by the laser emission unit driving device 46, but only the objective lens system 26 is moved. The focal position may be adjusted by Further, in the present embodiment, the force used for the tubular body 25 of the laser emission unit 22 is not limited to this. For example, an angular nose or the like may be used. Further, in the present embodiment, visible light is used as the illumination light Y, but other light beams may be used as long as they have a low energy density and there is no risk of damaging the object 12.

Claims

[1] (a) A laser processing apparatus for processing a workpiece by emitting a processing laser to a processing position of the workpiece, and (b) for processing to generate the processing laser Laser generator, (c) illumination device for emitting illumination light for illuminating the workpiece, (d) the laser generator for processing and the illumination device are optically connected, the laser for calorie and the illumination light A laser emitting unit for emitting the laser beam toward the workpiece, (e) a laser emitting unit driving device for moving the laser emitting unit closer to or away from the workpiece, (f) the laser emitting unit driving device The laser emitting unit is moved relative to the workpiece in the approaching and separating direction, and the workpiece illuminated by the illumination light is sequentially imaged at imaging positions where the separation distance of the laser emitting unit of the workpiece force is different. Camera (g) Sequential imaging at different imaging positions Focus detection data detected by pixels at positions corresponding to a plurality of in-focus detection positions in the screen, which are preset for use in detecting the shape of the workpiece, Are sequentially taken out, in-focus detection waveforms based on changes in the in-focus detection data are formed for each of the in-focus detection positions, and each in-focus detection waveform is calculated. Compare the peak values of the focus detection waveform,

(g-1) If all of the peak values are within a predetermined range, the workpiece is determined as a non-defective product, and the laser beam is emitted to the in-focus position of the laser beam emitting portion with respect to the workpiece. Move the part, and then operate the laser emitting part to output a command for performing laser beam irradiation by the laser emitting to the workpiece to the laser emitting part

(g-2) When the peak value 1 is out of a predetermined range of force, a command is issued to the laser emitting unit to determine that the workpiece is a defective product and to prevent laser emission. And an image processing device,

(h) Laser processing apparatus.

[2] The focus detection position of image processing is (a) The center of the workpiece and five points at each corner,

(b) each corner of the workpiece and eight points on each side,

(c) nine corners of each corner and each side and center of the cover object, or

(d) The laser processing apparatus according to claim 1, which is an arbitrary point on the plane of the workpiece added to the nine points.

The laser processing apparatus according to claim 1 or 2, wherein the processing laser is a second or higher harmonic.