KR100461025B1 - Laser marking method using eccentric camera lens - Google Patents

Abstract

The present invention discloses a laser marking method using an eccentric camera lens. In the disclosed laser marking method using a eccentric camera lens, a plurality of chips in a tray are recognized as a CCD camera, a marking pattern is set according to individual chips, and a laser beam from a laser oscillator is used to scan a galvano scanner and an f-theta lens. In the method of marking on a plurality of chips in the tray through, the center line of the imaging lens attached to the front end of the CCD camera is characterized in that the imaging is located at a predetermined distance away from the center line of the CCD camera. According to this, even if the chips in the tray are distracted by using a CCD camera, there is an advantage that it is possible to mark characters and the like at a certain position of the chips.

Description

Laser marking method using eccentric camera lens

The present invention relates to a laser marking method using an eccentric camera lens, and more particularly, to a method of laser marking by recognizing individual positions of a plurality of chips in a tray using an eccentric camera lens from a CCD camera.

1 is a view schematically showing the configuration of a conventional laser marking system. Referring to FIG. 1, the laser beam from the laser oscillator 10 passes through the x mirror 21 and y mirror 22 of the galvano scanner 20 and the f-theta lens 30 in the plurality of trays 40. Mark the surface of chips (c).

2 is a plan view illustrating a general tray 40 and chips c located therein. Referring to FIG. 2, the tray 40 is partitioned into rooms where each chip c enters such that a plurality of chips c are located. Since the size of this room is somewhat larger than the size of the chip, the chip in each room may move when the tray 40 is transferred. Therefore, when marking each chip in the tray 40 with the laser marking system, the marking position on the surface of the chip varies according to the position of each chip. Even the normal chips do not give the consumer confidence in the quality of the chip itself if the marking positions of the chips are not constant and cause dissatisfaction.

Therefore, a method of marking chips by chip by recognizing positions of chips in a tray by equipping the laser marking system with a CCD camera has been proposed.

However, when applying this method, a problem arises that the CCD camera installed between the f-theta lens and the tray does not cover all of the lower tray surface due to the interference with the f-theta lens.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method of laser marking corresponding to individual chips by recognizing the position of each chip in a tray using an eccentric camera lens.

1 is a view schematically showing the configuration of a conventional laser marking system.

2 is a diagram illustrating a general tray and chips located therein.

3 is a view schematically showing the configuration of a laser marking system according to a preferred embodiment of the present invention.

4 is a plan view showing the individual chips being deflected within the tray.

FIG. 5 is an extract of the camera and tray of FIG. 3 and illustrates an area recognized by the camera on the tray.

FIG. 6 is a view illustrating tilting the camera in FIG. 5 to completely cover an area on a tray.

7 is a view showing the arrangement of the camera and the tray according to a preferred embodiment of the present invention.

8 is a flow chart according to a preferred embodiment of the present invention.

* Description of Signs of Major Parts of Drawings *

10: laser oscillator 20: galvano scanner

21: x mirror 22: y mirror

30: f-theta lens 32: CCD camera

34: light 36: imaging lens

40: tray

In order to achieve the above object, the laser marking method using the eccentric camera lens of the present invention recognizes a plurality of chips in a tray as a CCD camera, sets a marking pattern according to individual chips, and then uses the laser beam from the laser oscillator. A method of marking on a plurality of chips in a tray via a galvano scanner and an f-theta lens,

A center line of the imaging lens attached to the front end of the CCD camera is positioned to be spaced apart from the center line of the CCD camera by a predetermined distance for imaging.

The center line of the imaging lens is spaced apart from the center line of the camera toward the f-theta lens by a predetermined distance.

Recognizing the chips, using the CCD camera to measure the x, y displacement and the tilt angle of the reference point of each chip deviated from the reference point in the tray.

In the marking step, marking is performed by adjusting the angles of the x mirror and the y mirror of the galvano scanner according to the marking pattern of the chip.

Hereinafter, a laser marking method using an eccentric camera lens according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this process, the thicknesses of layers or regions illustrated in the drawings are exaggerated for clarity.

3 is a view schematically showing the configuration of a laser marking system according to a preferred embodiment of the present invention, the same reference numerals are used for objects having the same structure as the conventional invention, and detailed description thereof will be omitted.

Referring to FIG. 3, a laser marking system receives light from a laser oscillator 10, a galvano scanner 20, an f-theta lens 30, and a plurality of chips c in a tray 40, which is a marking object. The galvano scanner 20 according to the CCD camera 32 for generating an electrical image signal, the light 34 for irradiating light to the tray 40, and the position information of the chip from the CCD camera 32. There is provided a controller (not shown) for adjusting the x mirror 21 and the y mirror 22. In front of the CCD camera 32, an imaging lens 36 is formed to form an object.

The galvano scanner 20 has an x mirror 21 and a y mirror 22 and a motor (not shown) for driving them, respectively, and adjusts the positions of the mirrors 21 and 22 to produce a laser beam. To the XY direction.

The f-theta lens 30 causes the incident laser beam to form the same sized focal point for the entirety of the marking object 40.

The charge coupled device (CCD) of the CCD camera 32 is a photoelectric conversion sensor that converts light into an electrical signal. The intensity of light entering the imaging lens 36 in front of the camera 32 is first recorded in the CCD. At this time, the light of the captured image is separated into different colors by the RGB color filter attached to the CCD. The separated colors are converted into electrical signals by the hundreds of thousands of light sensors (corresponding to the pixels) that make up the CCD. The analog signal from the CCD is converted into digital signals of 0 and 1, and an image signal is produced and output.

A plurality of cameras may be used for the CCD camera 32 to photograph the entire surface of the tray 40.

4 is a plan view showing one chip in the tray being deflected in the tray. Referring to FIG. 4, one chip c is positioned in one room of the tray 40. The chip c may be moved away from a certain point of the room while being moved in the room. To define the location of the chip, one corner of the inner surface of the room is taken as the reference point P1. In the figure, the upper left corner was defined as the reference point P1. Next, at the chip c, a position corresponding to the reference point P1 and adjacent one edge P2 is separated from the reference point P1 is determined. That is, in the drawings, the deviations from the x and y axes are defined as dx and dy, respectively. Next, in order to express the shape in which the chip c is located, the angle between the x-axis line passing through the reference point P2 of the chip and the line segment formed by one surface of the chip is defined as θ, and one chip c in the tray 40 is defined. ) Position is defined.

FIG. 5 is an excerpt of the camera and tray of FIG. 3 and illustrates an area recognized by the camera on the tray, and FIG. 6 shows an inclination of the camera in FIG. 5 to cover an area on the tray.

Referring to FIG. 5, when the camera 32 is vertically installed on the tray 40, the camera 32 is freely installed due to interference with the f-theta lens 30. Therefore, as shown in FIG. 4, a dead (D) area exists on the tray 40, which is not covered by the two cameras 32. In this case, when a wide field of view of the camera lens is used, it is possible to cover all areas on the tray 40, but the resolution of the camera is reduced because the focal length is shortened as the angle of view is widened.

The problem may be to recognize all the upper surface of the tray by installing the camera inclined at a predetermined angle as shown in FIG.

However, other problems arise when using this method of tilting the camera. That is, since the chips in the tray 40 are obliquely incident to the camera lens, the shape of the chips is perceived to be distorted according to the perspective of the incident distance. In other words, it is recognized that the length of the near distance is longer than the length of the far distance. Thus, the purpose of using the camera is undermined by the camera for accurately recognizing the position of the chip and recognizing the chip in an incorrectly distorted shape.

7 is a view showing the arrangement of the camera 32 and the tray 40 according to a preferred embodiment of the present invention. Referring to Fig. 7, the CCD camera 32 has an imaging lens 36 attached to its front end. At this time, the CCD camera 32 moves the imaging lenses 36 for observing the subject in a fixed state in a direction facing each other so that the centerline of the imaging lenses 36 shifts from the centerline of the CCD camera 32. It was made. Accordingly, even when the CCD camera 32 having the same angle of view as in FIG. 4 is used, a normal image can be recognized without a dead area on the tray.

The method of marking the surface of the plurality of chips in the tray 40 using the laser system will be described in detail. 8 shows a flow chart according to a preferred embodiment of the present invention.

Referring to the drawings, first, one chip (c) is positioned in each room of the tray 40. Subsequently, the tray 40 is positioned on a work bench on which a camera is installed (S1). At this time, it is important that the surface of each chip is located at the focal length of the f-theta lens 30.

Next, in the state where the light 34 is turned on to illuminate the lower tray 40, each camera 32 captures the position of each chip in the lower tray 40 (S2). At this time, when a plurality of cameras 32 are provided in accordance with the size of the tray 40, the area for imaging each camera 32 is distinguished in advance.

From the picked-up image, the positional information of each chip, that is, dx and dy, which are degrees of deviation of the corresponding chip from the reference point P1 of each room in the tray 40, and the angle of inclination from the reference line are measured (S2).

Subsequently, the marking pattern stored in the controller and the measured position of each chip are merged to input the marking pattern in which the chip position is corrected for each individual chip to the controller (S3).

Next, the surfaces of the individual chips are marked with a predetermined marking pattern (S4).

As described above, according to the laser marking method using the eccentric camera lens according to the present invention, even if the chips in the tray are distracted using the CCD camera, there is an advantage in that characters can be marked at a certain position of the chips.

Although the present invention has been described with reference to the embodiments with reference to the drawings, this is merely exemplary, it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined only by the appended claims.

Claims (4)

After recognizing the position of the plurality of chips in the tray with the CCD camera and setting the marking pattern according to the individual chips, the laser beam from the laser oscillator is marked on the plurality of chips in the tray through the galvano scanner and the f-theta lens. In the way, The CCD camera is disposed substantially perpendicular to the tray, and the center line of the imaging lens attached to the front end of the CCD camera is positioned to be moved a predetermined distance from the center line of the CCD camera toward the center of the f-theta lens. Recognizing chips; And And marking on the chip according to each of the recognized chips. delete The method of claim 1, wherein the recognizing the chips comprises: And an x, y displacement and an inclination angle at which the reference point of each chip deviates from the reference point in the tray using the camera. The method of claim 1, wherein the marking step, And marking by adjusting the angles of the x mirror and the y mirror of the galvano scanner according to the marking pattern of the chip.