WO2012134147A1

WO2012134147A1 - Visual inspection apparatus using a grid pattern of visible light and a grid pattern of invisible light

Info

Publication number: WO2012134147A1
Application number: PCT/KR2012/002220
Authority: WO
Inventors: 박찬화; 김성현; 구자명; 김태준; 안보혁
Original assignee: 주식회사 미르기술
Priority date: 2011-03-31
Filing date: 2012-03-27
Publication date: 2012-10-04
Also published as: KR101245623B1; KR20120111198A

Abstract

According to the present invention, a visual inspection apparatus captures an object to be inspected using a camera, wherein said object is being assembled or mounted during a part-assembling process, and compares the captured image with a previously inputted image in order to determine whether to pass or fail the object to be inspected. The visual inspection apparatus comprises: a stage unit for fixing the object to be inspected to an inspection location or transferring the object to be inspected; a lighting unit, which is arranged above the stage unit to illuminate the object to be inspected; a central camera unit arranged at the center of the lighting unit so as to acquire the two-dimensional shape of the object to be inspected; a plurality of side camera units arranged at the side of the central camera unit; a plurality of units for irradiating a grid pattern arranged among the cameras of the side camera units at the side of the central camera unit; a visual processing unit which reads the image captured by the central camera unit to determine whether to pass or fail the object to be inspected; and a control unit for controlling the stage unit, the units for irradiating a grid pattern, and the camera units. Any one of the units for irradiating a grid pattern is configured to irradiate a grid pattern of visible light having a predetermined period, and another unit for irradiating a grid pattern is configured to irradiate a grid pattern of invisible light having another predetermined period.

Description

Vision Inspection System Using Grid Pattern of Visible Light and Grid Pattern of Invisible Light

The present invention relates to a vision inspection apparatus, and more particularly, by performing a vision inspection using a grid pattern of visible light and a grid pattern of invisible light such as infrared rays or ultraviolet rays, the height of the inspection object can be measured quickly and accurately. The present invention relates to a vision inspection apparatus using multiple grids of different colors.

In general, Surface Mounting Technology (SMT) for assembling surface-mounted components to a printed circuit board (PCB) or the like is a technique for miniaturizing / integrating surface-mounting components (SMD) and such surface-mounted components. Development of precision assembly equipment for precise assembly and technology for operating various assembly equipment.

Surface mount lines consist of equipment such as surface mounters and vision inspection equipment. The surface mounter is a device for mounting surface-mounted parts on a printed circuit board. The surface mounter receives various surface-mounted parts supplied in the form of tape, stick, and tray from a feeder and places them on the mounting position on the printed circuit board. Perform.

The vision inspection apparatus inspects the mounting state of the surface mount component before or after the soldering process of the surface mount component is completed and transfers the printed circuit board to the next process according to the inspection result.

A typical vision inspection apparatus includes a lighting unit to which light is irradiated using a lamp or the like, a camera unit for photographing image information of various components mounted on an inspection unit and reflecting light from the lighting unit. It comprises a half mirror for transmitting the shape of the inspection object to the camera unit while being reflected on the inspection object.

Here, the lighting unit is arranged in the housing by arranging a plurality of lamps in a plurality, when the illumination of the inspection object to supply power to the plurality of lamps to irradiate light.

Conventional vision inspection method, when the inspection object is transported horizontally through the conveyor, adjusts the initial position in the positioning device, and after the adjustment is completed and irradiated with light through the grid on the LED component or printed circuit board, the irradiated light is By analyzing the shadow shape formed on the surface of the inspection object, the three-dimensional height is measured.

Then, by calculating the photographing part and comparing with the reference value, the inspection of the good / bad of the component mounting associated with the height, or the presence / absence of the mounting of the surface mounting component.

All of the above inspection methods measure the two-dimensional shadow shape and calculate the three-dimensional height by using a trigonometric function.

Therefore, clearly photographing and distinguishing the shadow pattern formed by the irradiated light is a very important factor in the vision inspection apparatus using the structured light.

However, as shown in FIG. 1, when the grid object is irradiated with a plaid light on a test object having a height and is photographed in plan view, if the height of the test object is relatively very high than the spacing of the grid pattern, the grid pattern is irradiated on the test object. It is not possible to distinguish which of (1, 2, 3) and the bottom lattice 1-1, 2-1, 3-1 are the same lattice in the first place.

Therefore, such a factor may cause an error in height inspection, which increases the number of image photographs required for height measurement to eliminate such an error, and complicates the height calculation process based on the image photograph. This delays the overall time spent.

On the other hand, all of the above inspection method to calculate the three-dimensional height by measuring the two-dimensional shadow shape using a trigonometric function.

However, as shown in FIG. 2, the conventional vision inspection apparatus includes an illumination unit 110 to which light is irradiated using a lamp and the like, and an image of various components installed on the inspection object by being installed on the illumination unit 110. And a half mirror 130 for reflecting the light from the illumination unit 110 to capture information and transmitting the shape of the inspection object to the camera while reflecting light from the illumination unit 110.

Here, the lighting unit 110 is arranged in the housing 140 by arranging a plurality of lamps, and, when irradiating the light to the inspection object to supply power to the plurality of lamps to irradiate light.

In the conventional vision inspection apparatus, a half mirror provided for capturing an image while reflecting light is disposed in front of the central camera unit, thereby preventing a clearer image.

In addition, since the light from the lighting unit is directly irradiated on the surface of the inspection object, there is a problem that the portion of the light is directly irradiated by overlapping the light is relatively dark while the portion of the light density is relatively dark.

In addition, since a configuration such as a laser or a camera for recognizing whether the inspection target substrate is mounted in the correct position is accommodated in the central camera portion, the type of the overall configuration accommodated in the housing for accommodating the central camera; The increase in size and weight causes inconvenience in maintenance.

The present invention has been made to solve the above problems, to provide a vision inspection apparatus capable of measuring the height of the inspection object quickly and accurately.

Still another object of the present invention is to provide a vision inspection apparatus capable of improving the uniformity of light irradiated onto a surface of an inspection object.

Still another object of the present invention is to provide a vision inspection apparatus capable of capturing a clearer image by removing a half mirror disposed in front of a central camera unit.

Vision inspection apparatus according to the present invention for achieving the above object is to determine the good or bad of the inspection object by comparing the photographed image with the pre-input target image after taking the inspection object assembled or mounted during the assembly of the parts with the camera An apparatus for vision inspection, comprising: a stage unit for fixing or transferring an inspection object to an inspection position, an illumination unit positioned at an upper portion of the stage unit and providing illumination to the inspection object, and positioned at a center of the illumination unit A central camera unit for acquiring a two-dimensional shape of the camera, a side camera unit disposed in a plurality of sides of the central camera unit, and a plurality of lattice pattern irradiation units disposed between the camera and the camera of the side camera unit at the side of the central camera unit; And, by reading the image taken by the central camera unit the inspection object And a control unit for controlling the stage unit, the grid pattern irradiation unit, and the camera unit. The grid pattern irradiation unit of one of the grid pattern irradiation units includes a predetermined period (interval) size. Irradiating the grid pattern of visible light having a, and another grid pattern irradiation unit is characterized in that configured to irradiate the grid pattern of invisible light having another predetermined period (interval) size.

Here, the invisible light may be infrared or ultraviolet light.

Preferably, the grid pattern irradiation unit comprises any one of a liquid crystal panel or a micromirror module.

Preferably, the grid pattern of the visible light and the grid pattern of the invisible light are configured to be irradiated at the same time.

Meanwhile, a light diffusing unit may be disposed in front of the lighting unit.

Here, the lighting unit may include a horizontal lighting unit for irradiating light in the vertical downward direction and an inclined lighting unit for irradiating light in the oblique direction.

The plurality of grid pattern irradiation units may be disposed to face each other with respect to the central camera unit.

The side camera parts may be disposed to face each other with respect to the center camera part.

Preferably, the light diffusing unit is disposed in front of both the horizontal lighting unit and the inclined lighting unit.

On the other hand, at one side of the central camera unit may be a positioning camera unit for positioning the inspection object.

Here, the positioning lighting unit and the half mirror may be disposed in front of the positioning camera unit.

Preferably, the angle between the central camera portion and the grid pattern irradiation portion on the side view is 25 degrees to 45 degrees.

According to the present invention, the height of the inspection object can be calculated quickly and accurately.

In addition, the uniformity of the light irradiated on the surface of the inspection object can be improved.

In addition, by removing the half mirror disposed in front of the center camera portion, it is possible to capture a clearer image.

Fig. 1A is a perspective view showing a state in which a lattice pattern is irradiated to the part.

FIG.1 (b) is a top view which shows the state which irradiated the grid with a component.

2 is a side cross-sectional view of a conventional vision inspection apparatus.

3 is a schematic side view of a vision inspection apparatus according to the present invention.

4 is a schematic plan view of a vision inspection apparatus according to the present invention.

5 is a conceptual diagram showing the relationship between the period of the lattice pattern and the height of the parts.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration of the present invention.

Prior to this, the terms used in this specification and claims should not be construed in a dictionary sense, and the inventors may properly define the concept of terms in order to explain their invention in the best way. It should be construed as meaning and concept consistent with the technical spirit of the present invention.

Therefore, the configurations shown in the embodiments and drawings described herein are only preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, and various equivalents may be substituted for them at the time of the present application. It is to be understood that water and variations may exist.

3 is a schematic side view of a vision inspection apparatus according to the present invention, Figure 4 is a schematic plan view of the vision inspection apparatus according to the present invention.

3 and 4, the vision inspection apparatus according to the present invention is a good or bad object of the inspection object by comparing the photographed image with a pre-input target image after taking the inspection object assembled or mounted in the assembly process with the camera A vision inspection apparatus with improved image clarity for discriminating an image, comprising: a stage unit 10 for fixing or transferring the inspection object 5 to an inspection position, and an upper portion of the stage unit 10, wherein the inspection object A lighting unit 20 for providing illumination to the (5), a central camera unit 30 for obtaining a two-dimensional shape of the inspection object 5 is located in the center of the lighting unit 20, and the central camera unit ( The grid pattern irradiation unit 50-2, 50-4, 50-6, 50-8, which are arranged in a plurality of sides on the side, and the image photographed by the central camera unit 30 are read and the inspection object is good. Or the vision processor 60 for determining a defect, and And a control unit 70 for controlling a tab part 10, the grid pattern irradiation unit 50-2, 50-4, 50-6, 50-8, and the central camera unit 30. One of the grid pattern irradiation units (50-2, 50-4, 50-6, 50-8) irradiates a grid pattern of visible light having a predetermined period (interval) size, and another grid pattern The irradiator is configured to irradiate a grid pattern of invisible light rays having another predetermined period (interval) size.

Vision inspection apparatus of the present invention is installed to perform the vision inspection before moving to the next process through the conveyor of the preceding equipment, when inspecting the surface-mounted parts of the printed circuit board after the surface mounting work in the surface mounting line .

Such vision inspection apparatus can be installed in a manner that is arranged in the space formed between the conveyor of the line, trailing equipment and the conveyor, can also be used in the form of a single table without being connected to the line, trailing equipment.

Here, the stage unit 10 is a component that provides a space in which the inspected object 5 to be inspected is seated, and a position adjusting unit (not shown) and a high position for adjusting and fixing the position of the inspected object 5. It may be configured to include a government (not shown).

Here, the lighting unit 20 is installed on the upper portion of the stage unit 10 continuously or intermittently along the circumferential direction around the central camera unit 30.

The lighting unit 20 is a component that provides illumination to the inspection object 5 in order to secure accurate image information of the inspection object 5, by placing a plurality of lamps or LED bulbs to the inspection object (5) ) Can be arranged to illuminate from side to side.

The lighting unit 20 includes a horizontal lighting unit 22 and the inclined lighting unit 23.

Here, the horizontal lighting unit 22 is installed on the upper portion of the stage 10 serves to provide the light incident to the inspection object (5) perpendicularly.

The inclined light unit 23 is disposed at the side of the vertical light unit 22 to provide light in the oblique direction.

The central camera unit 30 is a component for photographing the inspection object 5 in a planar manner, and preferably includes a CCD (charge coupled device) camera or a CMOS image sensor camera to have sensitivity even in an infrared or ultraviolet region. It is provided, but is configured to shoot the visible light and invisible light image at the same time.

The grid irradiated by the grid pattern irradiation unit 50-2, 50-4, 50-6, and 50-8 while performing the two-dimensional inspection of the inspection object 5 by the central camera unit 30. By measuring the degree of deformation of the pattern can be measured the height of the inspection object.

In the case of the conventional vision inspection apparatus, a half mirror is disposed in front of the center camera unit, and reflects the light from the lighting unit, and is configured to capture an image through the camera. In the present invention, the center camera unit 30 No half mirror is placed in front.

Therefore, it is possible to capture a clearer image through the central camera unit 30.

A plurality of side camera units 40-2, 40-4, 40-6, and 40-8 are arranged symmetrically with respect to the center camera unit 30 on the side of the central camera unit 30, thereby providing an image. Eliminate blind spots and take pictures quickly.

As shown in FIG. 4, the four side camera parts 40-2, 40-4, 40-6, and 40-8 are symmetrically arranged with respect to the center camera part 30, such as a substrate. Examine the lifting and uninsertion of the parts placed on the inspection object.

The grid pattern irradiation unit (50-2, 50-4, 50-6, 50-8) is a configuration for measuring the height by irradiating the grid pattern on the inspection object 5, a liquid crystal panel or a digital micromirror display ( DMD: Digital Micromirror Display and light source.

Thus, the shadow of the grid-shaped shadow is irradiated onto the inspection object 5 under the control of the control unit 70, and the degree of deformation of the grid-shaped shadow through the central camera unit 30, We can calculate the height of.

The grid pattern irradiation unit 50-2, 50-4, 50-6, 50-8 also has four grid pattern irradiation units 50-2, 50-4, 50-6, centered on the central camera unit 30. 50-8) are arranged symmetrically, and are configured to irradiate the grid 5 with the inspection object 5 simultaneously or sequentially.

Here, any one of the grid pattern irradiation unit (50-2, 50-4, 50-6, 50-8) of the grid pattern irradiation unit irradiates a grid pattern of visible light having a predetermined period (interval) size, Another grid pattern irradiation unit is configured to irradiate the grid pattern of invisible light beams having another predetermined period (interval) size.

Thus, for example, the larger intervals of the grid are irradiated with visible light such as red, wave, green, etc., and the smaller intervals of the grid are simultaneously irradiated with infrared or ultraviolet rays, thereby reducing the time required for measuring the height of the component. This allows more accurate height measurements.

Preferably, the arrangement angle a between the grid pattern irradiation unit 50-2, 50-4, 50-6, 50-8 and the central camera unit 30 is arranged in an angle range of 25 degrees to 45 degrees. .

When the angle (a) is smaller than 25 degrees, the degree of deformation of the grid pattern according to the height of the component is small, which may cause an error in the height calculation. When the angle (a) is larger than 45 degrees, the grid pattern irradiation unit ( 50-2, 50-4, 50-6, 50-8), the difference in the width of the grid pattern irradiated on the near and far sides is too large, which may cause errors in the height calculation.

This is because, when disposed in the angular range, when the irradiated grid pattern is photographed through the central camera unit 30, the grid pattern is properly deformed according to the height of the inspection object.

On the other hand, the vision processing unit 60 calculates the image information of the inspection object 5 obtained from the camera unit through a mathematical process such as Fourier transform (Fourier Transform), and compares with the reference value input in advance The good or bad of the object 5 is determined.

In addition, the control unit 70 is a component including a motion controller for controlling the driving and operation of the stage unit 10 and the camera unit, and may be provided to control driving of the entire vision inspection apparatus according to the present invention.

The controller 70 is responsible for physical control such as photographing position control of the vision inspection apparatus, processing of photographed images, and lighting unit control according to a system control program, as well as performing inspection task and data calculation task.

In addition, the control unit 70 is in charge of the overall control of the vision inspection apparatus, such as output device control for outputting the work contents and inspection results to the monitor and input device control for the operator to input the settings and all the details.

On the other hand, the light diffusion unit 25, such as a light diffusion plate is disposed in front of the illumination unit 20, so that the light from the illumination unit 20 is evenly irradiated to the entire area of the inspection object.

Thus, by reducing the difference between the dark portion and the bright portion on the inspection object (5) can take a clearer image.

The light diffusion unit 25 is configured to be bent in a side cross-section so that the light diffusion unit 25 can be disposed in front of both the horizontal light unit 22 and the inclined light unit 23.

On the other hand, at one side of the central camera unit 30 is positioned a positioning camera unit 80 for checking the position of the inspection object.

Here, the positioning lighting unit 84 and the half mirror 82 is disposed in front of the positioning camera unit 80.

Thus, compared to the case of confirming the position of the inspection object through the conventional central camera, the configuration for positioning is accommodated in the housing of the separate positioning camera unit 80, thereby reducing the housing diameter of the central camera unit 30 It can be reduced and management is easy even in case of accessory failure.

Referring to Figure 5, when describing the grid irradiation process of the vision inspection apparatus according to the present invention.

First, in FIG. 5, the straight lines connecting the points a, b, c and d conceptually show the height that can be measured by the lattice pattern having a large period.

That is, a large periodic grid has a resolution of 500 micrometers, so all heights from 0 to 500 micrometers are recognized as the same height, and another height from 500 to 1000 micrometers.

This conceptually describes the resolution when measuring the height of a part using a large periodic grid, and specific numbers may vary depending on the periodic size of the grid.

The grid pattern irradiation unit 50-2, 50-4, 50-6, and 50-8 may first measure the approximate height of the component by irradiating the grid pattern with a large gap.

That is, when the height of the hexahedral shaped part illustrated in FIG. 5 is 1680 micrometers, the height of the part is primarily measured in the range of 1500 and 2000 micrometers through the lattice of a large period.

Next, the grid pattern with a small period is examined to determine that the height from point d to point R is 180 micrometers.

Thus, the total height of the part is 1500 + 180, measured 1680 micrometers.

If the height of the part is measured by using only one lattice of the small period without the height measurement process through the lattice of the large period, the lattice pattern corresponding to the first lattice pattern on the left in FIG. 1 Plaid, 2-1 Plaid, 3-1 Plaid, that is, whether the plaid on the top of the part and the plaid on the bottom coincide after several cycles (lattice spacing) Cannot be judged.

Therefore, such a factor may cause an error in the height inspection, which complicates the calculation process required for the height inspection and eliminates the time required for the inspection.

In the present invention, as described above, a large period plaid and a smaller resolution plaid with a higher resolution are used together, but through a large period plaid, the approximate height range is measured, and a small period plaid is used. By allowing more accurate height measurements, height checks can be performed quickly and accurately.

The large cycle plaid and the small cycle plaid may be photographed by irradiating the large cycle plaid and the small cycle plaid once, or irradiating the large cycle plaid once according to the requirements of the height inspection device. Photographed by a small period, the grid may be configured to enable a more accurate height measurement by photographing while moving between the grid of a large period.

Here, the grid pattern of the visible light and invisible light such as red, blue, green, etc. according to the period size of the grid irradiated by the grid pattern irradiation unit (50-2, 50-4, 50-6, 50-8) Investigating the grid pattern separately allows you to measure the height of components more clearly and quickly.

That is, for example, the lattice of large periods can be irradiated with visible light, and the lattice of smaller periods can be irradiated with infrared rays or ultraviolet rays.

The grid pattern irradiated by the grid pattern irradiation units 50-2, 50-4, 50-6, and 50-8 may irradiate the grid pattern of a large period and the grid pattern of a small period simultaneously or sequentially.

That is, each grid pattern irradiation unit (50-2, 50-4, 50-6, 50-8) through the first check the lattice of a large period, and then the lattice of the small period, or Smaller grids can be irradiated at the same time.

The larger plaid spacing is preferably comprised three to six times larger than the smaller plaid spacing.

If the lattice spacing of a large period is less than three times, the difference in measurement resolution due to the difference of the period size is not large, which is not desirable for more accurate height measurement.If the lattice spacing of a large period exceeds six times, The difference between the spacing and the small spacing becomes so large that it has an undesirable effect on the sharpness of the grid shape finally reflected on the inspection object.

As mentioned above, although the present invention has been described by way of limited embodiments and drawings, the technical idea of the present invention is not limited thereto, and a person having ordinary skill in the art to which the present invention pertains, Various modifications and variations may be made without departing from the scope of the appended claims.

Claims

A vision inspection device for determining whether the inspection object is good or bad by taking a photograph of an inspection object assembled or mounted in a component assembly process and comparing the photographed image with a previously input target image.

A stage unit for fixing or transferring the inspection object to an inspection position;

An illumination unit positioned above the stage unit and providing illumination to the inspection object;

A central camera unit positioned at the center of the illumination unit to obtain a two-dimensional shape of an inspection object;

A side camera unit disposed in a plurality of side portions of the central camera unit;

A plurality of lattice pattern irradiation units disposed between the camera and the camera at the side of the central camera unit;

A vision processing unit which reads the image photographed by the central camera unit and determines whether the inspection object is good or bad;

A control unit for controlling the stage unit, the grid pattern irradiation unit, and the camera unit,

One of the grid pattern irradiation unit of the grid pattern irradiation unit irradiates a grid pattern of visible light having a predetermined one cycle size, another grid pattern irradiation unit is a grid pattern of invisible light having another predetermined cycle size Vision inspection apparatus using a grid of visible light and a grid of invisible light, characterized in that configured to irradiate.
The method of claim 1,

The invisible light is a vision inspection device using a grid of visible light and a grid of invisible light, characterized in that the infrared ray or a magnetic line.
The method of claim 1,

The grid pattern irradiator includes a liquid crystal panel or a micromirror module comprises a grid pattern of visible light and a grid pattern of invisible light, characterized in that the configuration.
The method of claim 1,

And the grid pattern of the visible light and the grid pattern of the invisible light are irradiated at the same time.
The method of claim 1,

A light inspection unit using a grid of visible light and a grid of invisible light, characterized in that the light diffusion unit is disposed in front of the lighting unit.
The method of claim 1,

The lighting unit is a vision inspection device using a grid pattern of visible light and a grid pattern of invisible light, characterized in that it comprises a horizontal lighting unit for irradiating light in the vertical and downward direction and an inclined lighting unit for irradiating light in the oblique direction .
The method of claim 1,

The plurality of grid pattern irradiation unit is a vision inspection device using a grid pattern of the visible light and a grid pattern of invisible light, characterized in that disposed opposite to each other with respect to the center camera unit.
The method of claim 1,

The side camera unit is a vision inspection device using a grid pattern of the visible light and a grid pattern of invisible light, characterized in that disposed opposite to each other centered around the central camera.
The method of claim 1,

The light diffusing unit is a vision inspection apparatus using a grid pattern of visible light and a grid pattern of invisible light, characterized in that disposed in front of both the horizontal lighting unit and the inclined lighting unit.
The method of claim 1,

A vision inspection apparatus using a grid pattern of visible light and a grid pattern of invisible light, characterized in that a positioning camera unit is disposed at one side of the central camera unit to check the position of the inspection object.
The method of claim 10,

A positioning device and a half mirror are disposed in front of the positioning camera unit, the vision inspection apparatus using a grid pattern of visible light and a grid pattern of invisible light.
The method of claim 1,

Vision inspection apparatus using a grid pattern of visible light and a grid pattern of invisible light, characterized in that the angle between the central camera portion and the grid pattern irradiation section on the side view.