CN214161773U - Laser coding system with online quality monitoring function - Google Patents

Abstract

The utility model provides a simple structure, high, the laser of being convenient for to maintain that has on-line monitoring quality function of precision beat sign indicating number system. The utility model comprises a laser light source module (1), a light beam turning module (2), a laser beam expanding adjusting module (3), a collimation judging module (4) and a scanning focusing module (6), wherein the laser beam expanding adjusting module is used for amplifying the laser beam after turning or deflection; the collimation judging module is used for ensuring the collimation degree of the optical axis of the expanded laser beam; the scanning focusing module is used for focusing the laser beams on different positions of the marked object and marking required codes on the marked object through the etching and burning functions of the laser beams; still be provided with between collimation decision module and the scanning focus module and beat sign indicating number quality monitoring module (5), beat the sign indicating number quality monitoring module and be used for carrying out quality monitoring to the code that laser beam was beaten on the object of being marked, confirm the quality of code fast. The utility model discloses can be applied to the laser instrument field.

Description

Laser coding system with online quality monitoring function

Technical Field

The utility model relates to a laser instrument field especially relates to a laser coding system with online monitoring quality function.

Background

The laser coding is a method of using a laser to emit a beam of high-power laser, expanding the beam, focusing the beam on the surface of a marked workpiece, and gasifying the surface layer or the interior of the material or changing the color of the material, thereby leaving permanent marks. By the rotation of the vibrating mirror, the light spots can be converged at different positions of the surface of the workpiece to be machined. As shown in fig. 1, which is a schematic diagram of laser marking, expanded laser forms light rays with different incident angles by the rotation of a galvanometer in the X and Y directions, and the light rays are converged at different positions of a focal plane by an f-theta field lens to satisfy a relation f X theta = h, where f is a focal length of the field lens, theta is an included angle formed by the radians of the incident light and an optical axis of the field lens, and h is a distance from a mark position to the focal point on a focal plane of the field lens.

The laser marking can be used for marking any characters and patterns, the size and the line width of the characters can be from millimeter to micron, the laser marking has wide requirements in the manufacturing industry, and the marking mode is high in precision and not easy to fade. Compared with the traditional modes of mechanical carving, chemical corrosion, screen printing, ink printing and the like, the laser marking has the outstanding characteristics of low cost, high flexibility and capability of being controlled by a computer system, and the fastness and the permanence of the mark generated by the action of laser on the surface of a workpiece are the outstanding characteristics.

In the past, laser coding is more applied to patterns such as trademarks, decorations and the like, the sizes of the patterns are large, the patterns can be seen by naked eyes, and the requirements on precision and accuracy are not high. With the application of laser coding in various industries towards refinement and scale development, some patterns are printed into two-dimensional codes, which determines important information such as product identity. The two-dimensional code is limited by the size of a marked workpiece, the whole size of the two-dimensional code reaches the submicron level, the line width or the spot reaches the micron level, the two-dimensional code is an important identity basis of a single product, and if the product is missed or over-hit, great difficulty or even misjudgment is brought to the identification of the product. Therefore, the method has very high requirements on the quality and the accuracy of the code printing, and the quick and accurate inspection of the code printing quality is a more urgent need in the automation industry. The conventional detection mode is mainly characterized in that a high-power microscope lens is additionally arranged to shoot image codes to judge the code printing quality, but the method needs additional equipment, reduces the efficiency and is not beneficial to large-scale automatic industrial mass production and detection.

Also, for example, chinese document No. CN106964904A proposes a visual positioning method, where a red light preview device is disposed at a laser emitting position to indicate a marking position, a half-mirror is added behind the field mirror, and a light beam converged by the field mirror is reflected to a marked object, and a visual positioning module focuses on a marking plane through a transmitted surface according to a position determined by a red light stylus, so as to achieve positioning and code detection functions. However, because the semi-reflective and semi-transparent mirror is added in the light path, part of laser used for marking passes through the lens and is continuously reflected in the marking machine, stray light can be formed, the marking quality is influenced, and the scattered stray light has the risk of damaging human bodies or part of electronic equipment. The scheme does not explain a lens and a light source used by the vision module, so that a plurality of uncertain factors and risks are brought to the design of the whole laser marking light path. With the requirement of higher and higher precision of the marking patterns on the market, according to the diffraction limitation principle, in order to reduce the aperture of a light spot of laser passing through a rear focus of a field lens, a short-focus field lens is needed, generally, the rear working distance of the short-focus field lens is smaller, and thus, the distance between a marking object and the field lens is not enough to be placed into a semi-transparent and semi-reflective lens. In addition, this scheme places a dichroic mirror 51 in front of the mirror to indicate that the red light is combined with the laser light in front of the mirror, which requires that the rear mirror have a relatively high reflectivity for both the red light and the laser light. Some ultrafast mirrors used in high-precision marking machines are not necessarily capable of reflecting the wavelength corresponding to the indication light source, so that the application is limited.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that overcome prior art not enough, provide a simple structure, precision height, be convenient for maintain have on-line monitoring quality function laser beat sign indicating number system.

The utility model adopts the technical proposal that: the utility model comprises a laser light source module, a beam turning module, a laser beam expanding and adjusting module, a collimation judging module and a scanning focusing module,

the laser light source module is used for generating laser beams;

the beam turning module is used for carrying out light path turning transformation and beam deflection adjustment on the laser beam so as to enable the laser beam to vertically and coaxially pass through the center of the scanning focusing module;

the laser beam expanding and adjusting module is used for amplifying or reducing the laser beam after turning or deflecting;

the collimation judging module is used for ensuring the collimation degree of the optical axis of the expanded laser beam;

the scanning focusing module is used for focusing the laser beams at different positions of the marked object and marking required codes on the marked object through the etching and burning functions of the laser beams;

the laser marking device comprises a collimation judging module, a scanning focusing module, a marking quality monitoring module and a control module, wherein the collimation judging module and the scanning focusing module are arranged in parallel, the marking quality monitoring module is also arranged between the collimation judging module and the scanning focusing module, and the marking quality monitoring module is used for carrying out quality monitoring on codes printed on a marked object by a laser beam and rapidly determining the quality of the codes.

Further, the scanning focus module is including setting gradually scanning mirror and the field lens that shakes on laser beam's light path, scanning mirror that shakes change laser beam through the vibration on the horizontal plane with contained angle between the optical axis of field lens makes laser beam assemble different positions on the focal plane of field lens, the field lens is with laser beam focus on the focal plane.

Still further, beat sign indicating number quality monitoring module and include dichromatic to mirror, light source, infinity image device, focusing device and formation of image detecting device, the dichromatic sets up in the laser marking light path to the mirror, and accepts the transmission of laser beam speed and right the light that light source produced reflects, light that light source produced is right the focal plane of field lens is thrown light, and laser beam beats the sign indicating number back on being beaten the mark object, and the code formation of image of beating is at infinity, and this formation of image light passes through scanning galvanometer with the transmission of dichromatic to the mirror is incited on infinity image device's the mirror surface, infinity image device with formation of image light assemble in formation of image detecting device department, focusing device sets up infinity image device with between the formation of image detecting device.

Still further, the infinity imaging device is an off-axis parabolic reflector, a protective film is plated on the mirror surface of the off-axis parabolic reflector, the included angle between the incident optical axis and the emergent optical axis of the off-axis parabolic reflector is 90 degrees, the incident optical axis of the off-axis parabolic reflector and the imaging light are coaxially arranged on the emergent optical axis of the dichromatic reflector, and the imaging detection device is arranged on the emergent optical axis of the off-axis parabolic reflector.

Further, the infinity imaging device is a scope.

Still further, the illumination light source is a coaxial parallel light source, and an effective light emitting surface of the illumination light source is larger than a light inlet of the scanning galvanometer.

More specifically, the imaging detection device is an industrial camera.

In addition, the beam turning module is composed of at least two ultrafast mirrors, at least two ultrafast mirrors are arranged on the angle regulator, and the angle of the ultrafast mirrors is adjusted through the angle regulator.

Further, laser beam expanding adjustment module includes beam expanding lens and regulation platform, the beam expanding lens sets up on the regulation platform.

And finally, the collimation judging module consists of two cross wires which are coaxially arranged, the central shafts of the two cross wires and the central shaft of the light inlet of the scanning galvanometer are coaxially arranged, and the planes of the two cross wires are mutually balanced and are vertical to the central shaft of the scanning galvanometer.

The utility model has the advantages that: the utility model discloses set up between module and the scanning focus module and beat the sign indicating number quality control module and come to carry out the quality monitoring to the laser beam code of beating down on being beaten the mark object in the collimation, confirm the quality of code fast, compare with prior art, the utility model discloses utilize the field lens to carry out the quality monitoring as the partly of control imaging module, avoided additionally adding the easy interference of the structure that the prism caused, bring the risk that parasitic light caused easily, be fit for short focus field lens more, effectively avoidd the short disadvantage of back working distance, and magnification can obtain promoting. The method is beneficial to small-size and high-precision coding application; the marking quality monitoring module is used as an integral module, can be effectively and conveniently replaced, and does not influence the normal marking light path work by adopting the combined beam of the dichromatic directional mirror and the marking light path; the effect of field lens chromatic aberration is considered, the coding quality monitoring module is provided with the focusing mechanism, axial chromatic aberration caused by a monitoring light source can be compensated conveniently, and therefore imaging is adjusted to the clearest state.

Drawings

FIG. 1 is a schematic diagram of prior art laser marking;

FIG. 2 is a simplified schematic diagram of the present invention;

FIG. 3 is a simplified block diagram of the coding quality monitoring module;

FIG. 4 is a graph of the transmittance of the dichroic mirror versus the laser beam and the illumination beam;

FIG. 5 is an image of the scanning focusing module;

FIG. 6 is a schematic diagram of an optical path of an infinity imaging device using a perspective mirror;

fig. 7 is a schematic diagram of a simple structure of the third embodiment.

Detailed Description

The utility model discloses quality monitoring problem design after the sign indicating number is beaten to the based on laser, its concrete scheme as follows.

The first embodiment is as follows:

as shown in FIG. 2, the present invention comprises a laser source module 1, a beam turning module 2, a laser beam expanding and adjusting module 3, a collimation judging module 4 and a scanning and focusing module 6,

the laser light source module 1 is used for generating laser beams;

the light beam turning module 2 performs light path turning transformation and light beam deflection adjustment on the laser beam so that the laser beam vertically and coaxially passes through the center of the scanning and focusing module 6;

the laser beam expanding and adjusting module 3 is used for amplifying or reducing the laser beam after turning or deflecting;

the collimation judging module 4 is used for ensuring the collimation degree of the optical axis of the expanded laser beam;

the scanning focusing module 6 is used for focusing the laser beam on different positions of the marked object and marking a required code on the marked object through the etching and burning functions of the laser beam;

and a coding quality monitoring module 5 is also arranged between the collimation judging module 4 and the scanning focusing module 6, and the coding quality monitoring module 5 is used for carrying out quality monitoring on codes printed on a marked object by a laser beam and rapidly determining the quality of the codes.

In this embodiment, the laser source module 1 employs a femtosecond laser with a center wavelength of 1065nm, the diameter of the light beam 11 is D1, and D1 in this embodiment is 2 mm.

Scanning focus module 6 shakes mirror 61 and field lens 62 including setting gradually the scanning on laser beam's light path, scanning shake mirror 61 through the vibration on the horizontal plane change laser beam with contained angle between the optical axis of field lens 62 makes laser beam assemble different positions on the focal plane of field lens 62, field lens 62 focuses on laser beam on the focal plane. The clear aperture of the scanning galvanometer is D3, and D3 is more than or equal to D2, wherein D2 is the beam diameter D2 expanded by the beam expander. In this example, D3 is 10mm, the scanning galvanometer changes the included angle theta between the laser and the optical axis of the field lens through the vibration in the X and Y directions, so that the light beam is converged at different positions of the focal plane of the field lens, the marked plane of the marked object is placed on the focal plane, and the pattern with different colors from the surrounding surface is formed through the etching and burning of the laser. The focal length f1 of the field lens is 65mm in this example, and the field angle is ± 16 ° at the maximum, which means that the coding pattern diameter can be 65mm × 2 × tan16 ° =37.27mm at the maximum.

As shown in fig. 3, the coding quality monitoring module 5 includes a dichroic mirror 51, an illumination light source 52, an infinity imaging device 53, a focusing device 54 and an imaging detection device 55, the dichroic mirror 51 is disposed on a laser marking light path, and receives the transmission of laser light speed and reflects the light generated by the illumination light source 52, the light generated by the illumination light source 52 illuminates the focal plane of the field lens 62, after the laser beam codes on the marked object, the coded image is formed at infinity, the imaging light is incident on the mirror surface of the infinity imaging device 53 through the scanning galvanometer 61 and the emission of the dichroic mirror 51, the infinity imaging device 53 converges the imaging light at the imaging detection device 55, the focusing device 54 is disposed between the infinity imaging device 53 and the imaging detection device 55, in the present embodiment, by adjusting the distance between the imaging detection means 55 and the infinity imaging means 53, the image of the code on the camera is rendered at the clearest position. The infinity imaging device 53 is an off-axis parabolic reflector, a protective film is plated on the mirror surface of the off-axis parabolic reflector, the included angle between the incident optical axis and the emergent optical axis of the off-axis parabolic reflector is 90 degrees, the incident optical axis and the imaging light of the off-axis parabolic reflector are coaxially arranged on the emergent optical axis of the dichromatic reflector 51, the imaging detection device 55 is arranged on the emergent optical axis of the off-axis parabolic reflector, in the embodiment, the focal length of the off-axis parabolic reflector is 203mm, a silver protective film is plated, the reflectivity at 400-2000 nm is greater than 97%, and the included angle between the incident optical axis and the emergent optical axis is 90 degrees. The illumination light source 52 is a coaxial parallel light source, and the effective light emitting surface of the illumination light source 52 is larger than the light inlet of the scanning galvanometer 61, in this embodiment, the light emitting area of the light source is 25mm by 25 mm. The imaging detection device 55 is an industrial camera with a target surface of 1/2 inches.

In this embodiment, dichroism is placed on the laser marking light path to mirror 51, judge module 4 and in the collimation between the module 6 of focusing, dichroism becomes 45 contained angles to mirror 51 and laser axis 11, dichroism is the transmission to mirror 51 for laser wavelength, dichroism is 1.638 to the reflectivity of 1064nm laser in this scheme, can guarantee that most energy in the laser penetrates dichroism mirror 51, get into subsequent scanning galvanometer, minute quantity light is reflected to the light path outside, add black extinction cloth in side, the absorptivity is 97%, can absorb most miscellaneous light, the influence to normal marking and illumination light path is beaten to the basic elimination. The dichroic mirror reflects the wavelength corresponding to the illumination light beam, the illumination light path is 940nm near infrared light, and the reflectivity is 99.881%.

The light beam turning module 2 at least comprises two ultrafast mirrors 21, at least two ultrafast mirrors 21 are arranged on the angle regulator, and the angle regulator is used for adjusting the angle of the ultrafast mirrors 21. In this embodiment, the ultrafast mirror functions to turn the optical path and adjust the deflection of the laser beam, and the laser beam can vertically and coaxially pass through the center of the subsequent scanning and focusing module 6 by adjusting the deflection angle of the mirror. The reflecting mirror needs two pieces at least, and the scheme adopts 3 ultrafast reflecting mirrors.

The laser beam expanding and adjusting module 3 comprises a beam expanding lens and an adjusting platform, and the beam expanding lens is arranged on the adjusting platform. In this embodiment, the beam expander may have four-dimensional adjustments, a two-dimensional adjustment perpendicular to the optical axis plane and pitch and yaw adjustments along the optical axis direction. The beam expander is used for amplifying the laser beam, and the diameter of the expanded beam is D2, then D2= β 1 × D1, D1 is the diameter of the laser beam, β 1 is the amplification factor of the beam expander, the beam expander may be fixed or adjustable, and the amplification factor of the beam expander adopted in this embodiment is adjustable within a range of 2X to 10X.

The collimation determination module 4 is composed of two cross-shaped wires which are coaxially arranged, the central axes of the two cross-shaped wires are coaxially arranged with the central axis of the light inlet of the scanning galvanometer 61, and the planes of the two cross-shaped wires are mutually balanced and are perpendicular to the central axis of the scanning galvanometer 61. Here, the expanded laser optical axis is ensured to be parallel and coaxial with the crosshair connecting line by adjusting the four degrees of freedom of the laser beam expanding adjustment module 3.

In this embodiment, the illumination light source 52 emits a beam of parallel light, which is reflected to the subsequent scanning and focusing module 6 by the dichroic mirror 51, and then converged by the field lens, so as to illuminate the coded marker. The code is imaged at infinity through the scanning galvanometer, and light is reflected through the scanning galvanometer 61 and the dichroic mirror 51, is incident on the off-axis parabolic mirror 53, and is converged on the imaging detection device 55 through the off-axis parabolic mirror 53.

Fig. 5 is a schematic diagram of an imaging of a scanning focusing module, and since the galvanometer 61 and the dichroic mirror 51 are plane mirrors, they only function to fold the optical path and do not participate in the power distribution, which is not shown in detail.

71 is the object focal plane of 1064nm wavelength corresponding to the laser of the field lens, and is also the plane of the marked position, 72 is the object focal plane of 940nm wavelength corresponding to the illumination wavelength of the field lens, and the distance of the movement of 72 relative to 71 to the field lens is X₁In the illuminating and imaging optical path, the marked object is positioned in front of the object focus by x₁In this example x₁The thickness of the film is 0.4mm,

531 is the image focal plane of the module 53, focal length f of the module 53₂A parallel beam of light 81 is reflected by a mirror and focused at an image focal plane 531, f₂Is the distance from the center of mirror reflection surface 533 to image focal plane 531, in this example f₂200mm, because of chromatic aberration of the field lens 61, the illumination light 81 is not parallel light 82 after passing through the field lens, but a converged light is reflected by the off-axis paraboloid and converged on the image plane 532, and the distance between 532 and 531 is X₂Which satisfies the relationship X₁/ X₂=f₁^2/ f ₂2, in this example, X is obtained₂Is 200^2/65^2 ^ 0.3=2.84 mm.

The module 54 is a focusing module, and is composed of an internal thread mirror tube, an external thread mirror tube and a snap ring, wherein the lower end of the internal thread mirror tube is connected with the reflector, the external thread mirror tube is connected with the detector, and the camera target surface is considered to be flush with the image plane 533 if the imaging on the detector is most clear by rotating the relative positions of the two mirror tubes.

Effective magnification of the code printing monitoring module is beta₂，β₂= f₂/ f₁In this case β₂= 203/65=3.12。

The utility model discloses compare in aforementioned scheme, need not increase the speculum in the field lens rear, solved the short inapplicable problem of working distance behind the short burnt field lens, avoided extra introduction external optical element between long burnt galvanometer and the field lens to damage the field lens or by the risk of beating the mark object surface and causing.

Example two:

the off-axis parabolic mirror has high reflectivity, no chromatic aberration and spherical aberration, but a small field of view, and for some large-area marked objects, the monitoring system module can also use a transmission method, as shown in fig. 6, the difference between the embodiment and the first embodiment is that: the infinity imaging device 53 of the coding quality monitoring module is a perspective mirror. The reflective module 53 is replaced by a transmissive module 56, and the illumination light is focused by the transmissive module 56 to form an image on the target surface of the detector of the camera, in this case, the transmissive mirror is an air-spaced doublet lens with a focal length of 200 mm. In this case, large-area coding can be realized.

Example three:

as shown in fig. 7, if the marked object is a uniform transparent material, such as glass, plastic, etc. The method has the advantages that the illumination light only passes through the laser scanning module once, the energy loss is reduced, the space is saved, and the imaging module is directly connected with the scanning module in front, so that the pupil position connection is facilitated. A larger field of view can be seen, reducing vignetting.

Claims (10)

1. The utility model provides a laser system of beating sign indicating number with on-line monitoring quality function, includes laser light source module (1), its characterized in that: it also comprises a beam turning module (2), a laser beam expanding and adjusting module (3), a collimation judging module (4) and a scanning and focusing module (6),

the laser light source module (1) is used for generating laser beams;

the light beam turning module (2) carries out light path turning transformation and light beam deflection adjustment on the laser beam so that the laser beam vertically and coaxially passes through the center of the scanning focusing module (6);

the laser beam expanding and adjusting module (3) is used for amplifying or reducing the laser beam after turning or deflecting;

the collimation judging module (4) is used for ensuring the collimation degree of the optical axis of the expanded laser beam;

the scanning focusing module (6) is used for focusing the laser beams at different positions of the marked object and marking required codes on the marked object through the etching and burning functions of the laser beams;

the collimation judging module (4) and the scanning focusing module (6) are also provided with a coding quality monitoring module (5), and the coding quality monitoring module (5) is used for carrying out quality monitoring on codes printed by laser beams on marked objects and rapidly determining the quality of the codes.

2. The laser coding system with the function of online quality monitoring according to claim 1, wherein: scanning focus module (6) shake mirror (61) and field lens (62) including setting gradually the scanning on laser beam's light path, scanning shake mirror (61) through the vibration on the horizontal plane change laser beam with contained angle between the optical axis of field lens (62), make laser beam assemble different positions on the focal plane of field lens (62), field lens (62) focus on the focal plane with laser beam.

3. The laser coding system with the function of online quality monitoring according to claim 2, wherein: beat sign indicating number quality monitoring module (5) including dichromatic to mirror (51), light source (52), infinity image device (53), focusing device (54) and formation of image detecting device (55), dichromatic sets up in laser marking light path to mirror (51), and accepts the transmission of laser beam speed and right light that light source (52) produced reflects, light that light source (52) produced is right the focal plane of field mirror (62) is lighted, and laser beam beats the sign indicating number back on being marked the object, and the code formation of image of beating is at infinity, and this formation of image light passes through scanning galvanometer (61) with the transmission of dichromatic to mirror (51), incides on the mirror surface of infinity image device (53), infinity image device (53) with formation of image light converge in formation of image detecting device (55) department, focusing device (54) set up infinity image device (53) with formation of image detecting device (55) In the meantime.

4. The laser coding system with the function of online quality monitoring according to claim 3, wherein: the infinity imaging device (53) is an off-axis parabolic reflector, a protective film is plated on the mirror surface of the off-axis parabolic reflector, the included angle between the incident optical axis and the emergent optical axis of the off-axis parabolic reflector is 90 degrees, the incident optical axis of the off-axis parabolic reflector and the emergent optical axis of the imaging light ray are coaxially arranged on the dichromatic mirror (51), and the imaging detection device (55) is arranged on the emergent optical axis of the off-axis parabolic reflector.

5. The laser coding system with the function of online quality monitoring according to claim 3, wherein: the infinity imaging device (53) is a perspective mirror.

6. The laser coding system with the function of online quality monitoring according to claim 4 or 5, wherein: the illumination light source (52) is a coaxial parallel light source, and the effective light emitting surface of the illumination light source (52) is larger than the light inlet of the scanning galvanometer (61).

7. The laser coding system with the function of online quality monitoring according to claim 4 or 5, wherein: the imaging detection device (55) is an industrial camera.

8. The laser coding system with the function of online quality monitoring according to claim 1, wherein: the beam turning module (2) is at least composed of two ultrafast reflectors (21), at least two ultrafast reflectors (21) are arranged on an angle adjuster, and the angle adjuster adjusts the angle of the ultrafast reflectors (21).

9. The laser coding system with the function of online quality monitoring according to claim 1, wherein: the laser beam expanding and adjusting module (3) comprises a beam expanding lens and an adjusting platform, and the beam expanding lens is arranged on the adjusting platform.

10. The laser coding system with the function of online quality monitoring according to claim 2, wherein: the collimation judging module (4) is composed of two cross-shaped wires which are coaxially arranged, the central axes of the two cross-shaped wires are coaxially arranged with the central axis of the light inlet of the scanning galvanometer (61), and the planes of the two cross-shaped wires are mutually balanced and are vertical to the central axis of the scanning galvanometer (61).

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