KR20050023657A - Apparatus and method for an auto focus laser marking editable on the real image. - Google Patents

Abstract

PURPOSE: An automatic-focus object image laser marking device is provided to enable anticipation of marking quality and to achieve quick and exact marking. CONSTITUTION: An automatic-focus object image laser marking device comprises a CCD(Charge Coupled Device) camera and an image lens making an image of a marking target(31) on a sensor of the CCD camera. The camera is not installed toward the surface of the marking target and is installed parallel with the vertical direction of the marking target. The center of the CCD camera is situated to a place apart from an optical axis of the image lens at a predetermined distance and distortion occurring in seeing the marking target from the side or occurrence of perspective of the image is minimized.

Description

Apparatus and method for an auto focus laser marking editable on the real image.}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser marking system, and more particularly, to an apparatus for acquiring an image of a marking object with an imaging system and then estimating a position and shape to be marked before performing marking.

A typical laser marking system can be divided into a scanning marker and a mask marker according to the marking method. The scanning marker has a method of marking like a pen drawing, and is capable of forming an arbitrary pattern input to a program, and is a general laser marking apparatus currently used in most fields. Marking targets include metals, non-metals, ceramics, etc., and are advantageous for producing small quantities of various products. The mask-type laser marking machine performs a marking by forming a pulse laser beam transmitted through a mask having a pattern engraved on an object surface, and requires a mask pattern, and the mask pattern cannot be changed. It is mainly used for marking plastics, resins, paper labels, etc., and is suitable for processes requiring high speed marking in an advantageous manner for repetitive marking operations.

There is a thermal processing method for converting the energy of the laser beam into heat, and there is photochemical processing that directly cuts the molecular structure of the material by using high photon energy such as an ultraviolet laser. All cutting processes such as metal cutting, welding and marking are thermal processing methods, and the processing is determined according to the power density of the laser beam. In the case of marking, a power density of 10 ⁷ W / cm 2 or more is required, and a processing method using a phenomenon in which the material evaporates instantaneously at a power density higher than this.

Such laser marking is mainly used for semiconductor parts including IC package, various electronic parts such as resistors and capacitors, machine parts such as tools, presses, instrument name plates, automobile parts, cosmetics, precious metals and general household goods. Used to mark information related to the product.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning marker for marking using a scanner, wherein a typical scanning marker is used to scan and focus the laser generator and the generated laser beam to an arbitrary plane of the marking object. Consists of a paired scanner. Looking at the marking system developed until recently, the imaging camera system for acquiring the shape information of the object to be processed during laser marking can be examined until the optical system for acquiring the shape of the object to be processed under the scanner or under the scanner. Since the optical system, which is part of the vision system, is installed in the laser beam irradiation path, the optical distance from the X-Y scanner to the marking object is limited, and it is difficult to obtain real-time image information during marking by the scanner. there was. This can be affected by precision machining through the rapid irradiation angle formation of the laser beam, and it is also difficult to match the reference coordinate system of the scanner and the imaging camera system. And since the optical system is installed in the path of the laser beam, a purifier must be installed to prevent contamination of the optical system by dust or dust. In addition, when marking a variety of products the thickness of the product is different, it is necessary to adjust the focus position accordingly.

Therefore, an object of the present invention is to implement a laser marking system that compensates for the disadvantages of the conventional laser marking device and quickly executes high quality marking on various products. Specifically, in the laser marking system that performs a marking function by irradiating a marking object with a laser beam output from a laser, an automatic focus for measuring the distance to the object so that the focus is always automatically formed on the surface of the object. Regulating device; An image camera apparatus for acquiring a shape of an object to be processed into an edit screen of a marking program in an image state with less distortion through an image camera system of the present invention installed at an arbitrary position; An image editing apparatus (or program) for superimposing the editable state on the image of the object to which the character or image information to be marked is acquired in an editable state so as to know the marking position and shape after processing before processing; A typical imaging camera system is located in the space between two X-Y mirrors that make up the scanner, and features a scanner device configured to enable two-dimensional image acquisition with little distortion on the vertical plane of the marking object.

In the present invention will be described with reference to the accompanying drawings, a specific method for achieving the above object.

1 is a schematic diagram of a laser marking system according to the present invention, a laser generating device 10 for generating a laser beam, a scanner 11 for moving the generated laser beam to a specific coordinate on a plane, the marking object by converging the laser beam (31) An image of a flat field lens 12 forming a focal point at one point above, a distance sensor 50 measuring a distance to a marking object 31, and a workpiece 31 having almost no distortion. According to the control of the computer system 40 based on the data of the distortion correction type image camera device 20, which can be acquired, and a marking worktable 30 capable of automatically adjusting the height of the vertical axis.

In order to explain the principle of image acquisition of a marking workpiece 31 with less distortion, which is a part of the present invention, an image acquisition method of a general video camera will be described with reference to FIG. The principle of image acquisition will be described in comparison with FIG. A general image camera is composed of a CCD camera 21 and an image lens 22. The center 23 of the camera is arranged to coincide with the optical axis 24 of the image lens 22. The distance between the cameras 21 is such that the CCD camera sensor array (film in the case of a normal camera is positioned) is located at a portion 33 where the target image 31 is imaged in a reversed phase through the image lens 22. do.

The image camera 20 of FIG. 2A applied to the present invention also includes a CCD camera 21 and an image lens 22. However, it is characterized in that the central axis 23 of the CCD camera 21 is provided so as not to face the direction of the workpiece 31, but parallel to the normal to the normal on the workpiece surface. The center of the CCD sensor array of the camera 21 is not arranged to coincide with the optical axis 24 of the image lens, but is moved in parallel so that the image of the workpiece 31 is at an image forming position 32 as shown in FIG. It is characterized by arranging at a position. In FIG. 3, an image 35 acquired using a general video camera is shown in comparison with an image 34 acquired using a video camera 20 according to the present invention.

4 illustrates a method of acquiring an image with low distortion using a general video camera, which is designed in the present invention. The scanner used for laser marking consists of a mirror that controls the position of the X-axis of the laser beam and two mirrors 14 that control the position of the Y-axis, and the distance between these mirrors is suitable for operation and beam transmission. There is. In the present invention, a general image camera is used to configure an imaging system using an optical axis as a space between two scanning mirrors. In this case, since the optical axis of the image camera is arranged perpendicular to the surface of the marking object, an image having less two-dimensional distortion can be obtained, and the optical path of the laser beam for marking has no effect.

In addition, in the present invention, the real-time image obtained from the video camera is displayed on the background of the marking program, and then the characters or images to be marked are superimposed so that the position to be actually marked can be known.

5 shows a schematic diagram in which the scanner 11 is equipped with a distance sensor 50 capable of fine measurement in order to maintain a constant focal length from the scanner 11 to the marking object 31. When the marking objects 31 having different heights are positioned in the marking work platform 30, the signal emitted from the light source 51 in the distance sensor 50 is reflected from the surface of the marking object and sensed by the detection sensor 52. The output voltage changes according to the change of distance. The principle of automatic focal length maintenance is to find the point where the output voltage of the distance sensor 50 is measured to be equal to the value at the focal position while driving the marking work table 30 up and down by computer control.

FIG. 6 shows a schematic diagram of an auto focusing apparatus constructed using a laser diode that generates a 630 nm visible light laser beam, unlike the autofocus holding apparatus using a distance sensor in FIG. 5. When the marking object is at the focal point through the distortion-corrected video camera 20, the position of the marking object at the focal point is displayed on the program screen as shown in (61), and the laser diode 53 is positioned at the focal point. After adjusting the installation angle so that the center coordinate 61 and the laser beam 62 reflected from the object surface overlap, the marking program is programmed to adjust the work table to find the same condition to find the auto focus position.

7 (a), 7 (b) and 7 (c) illustrate differences in behavior seen on an image screen according to the height of the marking object 31. First, FIG. 7A illustrates a case where the marking object 31 is positioned higher than the focal point position 61. FIG. 7B illustrates an image in which the focal point display coordinates and the reflected laser diode beam are exactly overlapped at the focal point. . In addition, in FIG.7 (c), the marking object 31 is shown in the position lower than a focal point.

In the configuration of the laser marking system, an automatic focusing device, an apparatus for checking a shape after marking by overlaying marking contents on an image of an object before marking, and a distortion for acquiring an image having a low distortion from a position away from the path of the laser beam We present principles that can be modified in a variety of ways, including a calibrated video camera.

According to the present invention, in the laser marking system, the laser beam transmission path is provided by installing the image camera devices of the present invention in a position outside the optical path of the laser beam or in a position that does not cause any obstacle in the path of the laser beam. A laser marking system can be constructed that does not cause any interference. In this case, since the configuration of the laser optical system for marking is free, it is possible to implement precise marking quality.

In addition, distortion of an image similar to that generated when the marking object is viewed from the side, or perspective in the image is marked before real-time observation and marking of the object through the camera device of the present invention, which enables acquisition of an image with less distortion. It is possible to predict the result after marking by superimposing the intended character or shape on the image of the marking object, and in particular, it is possible to implement an effective marking in a product marking process of various shapes.

In addition, by developing the principle of maintaining the auto focus to the marking target by using the distance sensor and the principle and the device to maintain the auto focus by using the laser diode, the production speed is significantly improved compared to the general marking system that requires manual focus adjustment. Implementation is possible.

On the other hand, the present invention is capable of various modifications in addition to the description shown in the drawings, the technical protection scope of the present invention will be defined by the stated claims.

1: Schematic diagram of an autofocus laser imaging marking system according to the present invention

2 (a): Distortion-correction type video camera for image acquisition with low distortion

Figure 2 (b): general video camera for image acquisition

3 (a): Image acquired by arranging a distortion correction type video camera in a vertical direction

3 (b): Image obtained by arranging a general video camera in the direction of the object to be processed

4 is a structural diagram in which a general image camera is arranged to enable two-dimensional image acquisition through a space between two X-Y scanning mirrors of a scanner

5: Schematic diagram of an auto focus forming apparatus constructed using a distance sensor

6: Schematic diagram of an auto focusing apparatus constructed using a laser diode

7 (a): Focus position and position of the laser diode beam when the marking object is higher than the focal point

7 (b): Focus position and position of laser diode beam when the marking object is at the focal point

7 (c): Focus position and position of laser diode beam when the marking object is lower than the focal point

Name of detail in the drawing

10: laser generator

-11, 12, 13, 14: scanner, flat field lens, video camera mounting window, scanning mirror

-20, 21, 22: video camera device, CCD camera, image lens

-23, 24, 25, 26: center line of CCD camera, optical axis of image lens,

Recognition area of distortion correction type camera device, Image recognition area obtainable by using general video camera

-30, 31: marking workbench, marking object

-32, 33, 34: Image of processed object, image of marking object, image with little distortion

-40: PC and drive program for laser marker control

-50, 51, 52: distance measuring sensor, light source of the distance measuring sensor, reflected light measuring unit

-53, 54: laser diode, laser diode beam for distance measurement

-60, 61, 62: laser diode beam reflected from the surface of image screen, focal coordinates, marking object

Claims (5)

In a laser marking system for marking a laser beam generated by a laser on a surface of a marking object through a scanner, an apparatus for acquiring in real time the shape data of a marking object with low distortion without any optical interference on the transmission path of the laser beam is provided. CCD camera; It consists of an image lens for imaging the image of the marking object on the sensor of the CCD camera, characterized in that the installation direction of the image camera is installed in parallel with the vertical direction of the surface of the marking object, rather than being installed facing the surface of the marking object. In addition, the center of the CCD camera is positioned at a certain distance away from the optical axis of the image lens in the configuration of the CCD camera and the image lens so that the distortion caused when viewing the marking object from the side or the perspective in the image is minimized. Video camera device. The method of claim 1, wherein the image information acquired from the image camera apparatus is processed as a base image of a marking program edit screen, and thus the real-time video can be observed. A laser marking program for producing a marking program, which gives a function of superimposing a character or image information to be marked on the obtained image information of the marking target object so that the state of the product after marking can be estimated. In the laser marking system according to claim 1 or 2, the principle and apparatus of the automatic focusing to maintain a certain distance so that the laser beam is focused on the surface of the marking object automatically by using the distance sensor. In the laser marking system of claim 1 or 2, the principle and apparatus of the automatic focusing to maintain a certain distance so that the laser beam is focused on the marking object surface automatically by using the laser diode. In the laser marking system according to claim 1 or 2, a marking video camera configured to acquire an image of a marking object having the least distortion through a space between two XY scanning mirrors of a scanner using an imaging camera device having a general configuration. Array of devices.