WO2021056274A1

WO2021056274A1 - Full surface visual inspection system for an object having a sheet shape

Info

Publication number: WO2021056274A1
Application number: PCT/CN2019/107891
Authority: WO
Inventors: Furuse KAZUFUMI
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2019-09-25
Filing date: 2019-09-25
Publication date: 2021-04-01
Also published as: CN113316714B; CN113316714A

Abstract

A visual inspection apparatus (1) for inspecting an object (2) to be inspected having a sheet shape, which comprises a pair of flat surfaces (201,202), a pair of first side surfaces (203,204), and a pair of second side surfaces (205,206), the visual inspection apparatus (1) comprising: a transportation stage (4) for placing and transporting the object (2), comprising a rest portion (12) for fixing the object (2) with respect to the transportation stage (4) and moving between a first position (26) and a second position (28) along a first direction (a) in the horizontal plane; a flat surface capturing mechanism (6) comprising a flat surface capturing camera (22) for capturing an image of the object (2) along a third direction (c) perpendicular to the first direction (a) in the vertical plane; a first side surface capturing mechanism (8) comprising a first side surface capturing camera (32) for capturing the object (2) from one side along a second direction (b) perpendicular to the first direction (a) in the horizontal plane; a second side surface capturing mechanism (9) comprising a second side surface capturing camera (38) for capturing the object (2) from the other side along the second direction (b); and a reversing mechanism (10) for reversing the object (2) by 180 degrees at the second position (28) around a reversal axis (r), comprising a gripping portion (48) for gripping the object (2), wherein the reversal axis (r) forms an angle of 45 degrees with the first direction (a) in the horizontal plane including the reversal axis (r).

Description

FULL SURFACE VISUAL INSPECTION SYSTEM FOR AN OBJECT HAVING A SHEET SHAPE

TECHNICAL FIELD

The present invention relates to a full surface visual inspection system for an object having a sheet shape. More specifically, the present invention relates to an inspection system for automatically inspecting all surfaces of an object having a sheet shape.

BACKGROUND

Products such as a smartphone and tablet terminal have a substantially rectangular-parallelepiped shape generally comprising a front surface which is a rectangular plane consisting of longer sides and shorter sides, a back surface which is a plane opposite to the front surface, facing away from the front surface along a normal direction, and having the same shape of the front surface, a pair of longer side surfaces (right and left side surfaces) connecting respective longer sides of the front and back surfaces, and a pair of shorter side surfaces (front and rear side surfaces) connecting respective shorter sides of the front and back surfaces. In addition, the distance between the front surface and the back surface is significantly shorter than the length of the longer side and the shorter side. Accordingly, the shape of the products is a sheet shape having a certain thickness, and the shapes of the front and back surface are significantly different from those of the side surfaces.

These products are subject to visual inspection in their production process. This visual inspection is manually carried out by operators usually, but sometimes automatically carried out by capturing an image of the objected products and processing image data in order to detect micro defects. Patent documents 1 and 2 disclose examples for carrying out inspection by means of image processing technique.

All surfaces of the products are required to be subjected to such a visual inspection. Apparatuses for carrying out the visual inspection are disclosed in, for example, Patent Documents 3 to 7. However, in the objects to be inspected in these apparatuses disclosed in these patent documents, the dimensions of the front and back surfaces are not significantly different from those of the side surfaces. Furthermore, such apparatuses are not suitable for inspecting objects having sheet shape since the objects to be inspected in the apparatuses are very small.

Also, positions for supporting products to be inspected have to be changed depending on the surfaces to be captured in order to fix the products to be inspected in inspection by means of automatic inspection apparatuses. As illustrated in Figure 8, when fixing an object 300 to be inspected on a support stage 500 or gripping the object 300 with a gripper portion 600, the object to be inspected often has to be gripped and released, and the period for inspection increases, thereby this would lead to an increase of cost for production. In addition, repeating of gripping and releasing the object to be inspected would accumulate variation of gripping position and have harmful effects on quality of inspection. This problem may also occur in the case that the object to be inspected is fixed and captured by a camera 400 moved by a robot arm 700 with multiple moving axes.

Furthermore, if object-side resolution is set to the same degree to capture the front and the back surfaces and the side surfaces, a plurality of kinds of capturing mechanisms and transporting mechanisms should be prepared since the object to be inspected has a sheet shape. This causes the apparatus to grow in size. Also, if additional optical systems such as a camera and lighting are provided, arrangement and control of these systems become complex. Furthermore, when an edge of the object to be inspected is a curved surface, a plurality of mechanical portions would be required in view of resolution and depth of field in order to perform capturing of a curved surface at the same level as capturing of a flat surface. In addition, when there are many variations in the dimensions of the objects to be inspected, the amount of information to be learned by the apparatus also increases. Accordingly, inspection periods and production cost would significantly increase.

In addition, since the object to be inspected has a sheet shape and the thickness dimension is significantly smaller than the dimensions of longer side and shorter side, large blank spaces with no object arise in a field of view of the camera when capturing the side surfaces of the object.

Prior Art Documents:

[Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2011-99875

[Patent Document 2] Japanese Unexamined Patent Application, First Publication No. 2013-205234

[Patent Document 3] Japanese Unexamined Patent Application, First Publication No. 2017-44579

[Patent Document 4] Japanese Unexamined Patent Application, First Publication No. 2010-230514

[Patent Document 5] Japanese Unexamined Patent Application, First Publication No. 2007-114180

[Patent Document 6] Japanese Unexamined Patent Application, First Publication No. 2016-191620

[Patent Document 7] Japanese Unexamined Patent Application, First Publication No. 2007-7608

[Patent Document 8] Japanese Unexamined Patent Application, First Publication No. 2017-187485

SUMMARY

Accordingly, the present invention is directed to reduce the period and steps required for a product inspection process. More specifically, the present invention aims to provide an apparatus and method for automatically performing a full surface visual inspection of an inspection object having a sheet shape in a shorter period and in fewer steps than ever before.

In order to solve the problem mentioned above, the present invention provides an apparatus for visually inspecting the object to be inspected, which comprises a sheet shape having a pair of planar surfaces, a pair of first side surfaces and a pair of second side surfaces. The visual inspection apparatus comprises a transportation stage (4) for placing and transporting the object, which comprises a rest portion for fixing the object with respect to the transportation stage and moves between a first position and a second position along a first direction (front and back direction) in the horizontal plane. The visual inspection apparatus also comprises a flat surface capturing mechanism comprising a flat surface capturing camera for capturing the object along a third direction (up and down direction) perpendicular to the first direction in the vertical plane, a first side surface capturing mechanism comprising a first side surface capturing camera for capturing the object from right side along a second direction (left and right direction) perpendicular to the first direction in the horizontal plane, and a second side surface capturing mechanism comprising a second side surface capturing camera for capturing the object from left side along the second direction. Furthermore, the visual inspection apparatus comprises a reversing mechanism for reversing the object by 180 degrees at the second position around a reversal axis, comprising a gripping portion for gripping the object, wherein the reversal axis forms an angle of 45 degrees with the first direction in the horizontal plane including the reversal axis. In this visual inspection apparatus, when the transportation stage moves from the first position to the second position, the flat surface capturing mechanism, the first side surface capturing mechanism, and the second side surface capturing mechanism captures the one flat surface and the pair of first side surfaces. In this visual inspection apparatus, when the transportation stage moves from the second position to the first position, the flat surface capturing mechanism, the first side surface capturing mechanism, and the second side surface capturing mechanism captures the other flat surface and the pair of second side surfaces.

With this apparatus, reversal of the object by 180 degrees, i.e. turning the object around causes the object to rotate by 90 degrees since the reversal axis forms an angle of 45 degrees with the moving direction of the transportation stage. Accordingly, by arranging cameras on the upper side of the transportation stage and on both sides with respect to the moving direction of the transportation stage, six surfaces of the object can be captured during reciprocation of the transportation stage.

According to another embodiment of the present invention, the first side surface capturing mechanism and the second side surface capturing mechanism respectively comprise an optical component. This optical component is arranged between the side surface capturing camera and the object. Due to this configuration, it enables simultaneous multi-surface capturing of the side surface of the object. This technique is disclosed in Patent Document 8.

The present invention further relates to a visual inspection method for inspecting an object to be inspected having a sheet shape, which comprises a pair of flat surfaces, a pair of first side surfaces, and a pair of second side surfaces. This method comprises steps of: resting and fixing the object on a rest portion of a transportation stage positioned at a first position; moving the transportation stage from the first position to a second position along a first direction in the horizontal plane, wherein during the movement, a flat surface capturing mechanism captures the one flat surface along a third direction perpendicular to the first direction in the vertical plane, wherein the first side surface capturing mechanism captures one first side surface from one side of a second direction perpendicular to the first direction in the horizontal plane, and wherein the second side surface capturing mechanism captures the other first side surface from the other side of a second direction (b) ; reversing the object by 180 degrees around a reversal axis at the second position, wherein the reversal axis forms an angle of 45 degrees with the first direction in the horizontal plane including the reversal axis; moving the transportation stage from the second position to the first position along a first direction in the horizontal plane, wherein during the movement, a flat surface capturing mechanism captures the other flat surface along a third direction, wherein the first side surface capturing mechanism captures one second side surface from one side of a second direction, and wherein the second side surface capturing mechanism captures the other second side surface from the other side of a second direction; and removing the object from the transportation stage which has reached the first position.

According to the present invention, capturing is simplified since complex handling of the object is not required. Also, the number of capturing mechanisms can be decreased comparing with the prior art. Furthermore, since the object is gripped and released once, there is less accumulation of positional errors due to handling. In addition, it is easy to handle objects having different sizes. Accordingly, this leads to decreasing production cost.

A further advantage of the present invention is that by using optical components such as a prism and a mirror, even when the side surface of the object is curved, it is possible to separately capture multiple angles of the height direction of the object. Accordingly, it is possible to inspect the exterior of the object on, for example, 10 or 14 surfaces during one process. With this configuration, the period for inspection can be shortened.

Brief Description of the Drawings

Figure 1 shows a top view of the apparatus for visual inspection according to the present invention.

Figure 2 shows a front view of the apparatus for visual inspection according to the present invention.

Figure 3 shows a six-view drawing of the object to be inspected by means of the apparatus for visual inspection illustrated in Figure 1.

Figure 4 shows an enlarged view of the side surface capturing mechanism comprising the optical component.

Figure 5 shows a relation between field of view of the camera for capturing a side surface and the side surface of the object to be inspected.

Figure 6 shows a process for reversing the object to be inspected by a reversing mechanism.

Figure 7A shows that the object to be inspected is placed on the transportation stage at first position of the apparatus for visual inspection according to the present invention.

Figure 7B shows that the transportation stage moves from the first position to the second position, and the surfaces of the object are captured during the movement of the transportation stage.

Figure 7C shows that the gripper mechanism grips the object to be inspected at the second position to reverse it.

Figure 7D shows that the gripper mechanism has reversed the object to be inspected.

Figure 7E shows that the gripper mechanism released the object to be inspected and retracted.

Figure 7F shows that the transportation stage moves from the second position to the first position, and the other surfaces of the object are captured during the movement of the transportation stage.

Figure 8 shows examples of prior art of capturing direction of cameras and gripping positions for capturing all surfaces of view of the objects to be inspected.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present invention will be explained in detail with reference to the Figures. Figure 1 shows a top view of a visual inspection apparatus 1 according to the present invention. Figure 2 shows a front view of the visual inspection apparatus 1 according to the present invention. Figure 3 shows a six-view drawing of an object 2 to be inspected by means of the apparatus for visual inspection illustrated in Figure 1.

As illustrated in Figure 3, the object 2 to be inspected is a sheet-shaped parallelepiped having a certain thickness, specifically a rectangular solid such as a smartphone. Accordingly, the object 2 to be inspected comprises a substantially rectangular front surface 201 which is a reference plane, a back surface 202 which is a surface opposite to the front surface, a pair of longer side surfaces 203, 204 (left and right side surfaces) connecting longer sides of the front and back surfaces, and a pair of shorter side surfaces 205, 206 (front and rear side surfaces) connecting shorter sides of the front and back surfaces. The longer side surfaces and the shorter side surfaces may be constituted with a curved surface. The object 2 to be inspected can have another shape.

The visual inspection apparatus 1 generally comprises a base stage 3, a transportation stage 4 to carry the object 2 to be inspected and to transport the object 2 in a first direction (front and back direction) a in a horizontal plane, a flat surface capturing mechanism 6 to capture images of the flat surfaces, i.e. front and back surfaces of the object 2, a first side surface capturing mechanism 8 to capture images one side surface of the object 2, a second side surface capturing mechanism 9 to capture images the other side surface of the object 2, and a reversing mechanism 10 to reverse the front and back surfaces of the object 2 by 180°.

The transportation stage 4 is equipped on the base stage 3. The transportation stage 4 comprises a rest portion 12 on which the object 12 is placed during visual inspection. The rest portion 12 comprises a vacuum absorbing pad (not shown in the figures) on a surface on which the object 2 is placed. The object can be removably fixed on the rest portion 12 by means of the absorbing pad. In this embodiment, although the vacuum absorbing pad is used to fix the object 12, the object 12 can be fixed by using an adhesive gel sheet or the like.

The rest portion 12 is configured to form a clearance between the object 2 and the transportation stage 4 when the object 2 is placed on the rest portion 12. Thereby, a gripping portion 48 of the reversing mechanism 10 described later can be inserted between the object 2 and the transportation stage 4.

The transportation stage 4 can reciprocate by means of a drive arrangement (not shown in the figures) along the first direction (front and back direction) a between a mounting position 26 in which the object 2 is to be mounted on the rest portion 12 and a reversing position 28 in which the object 2 is to be reversed by the reversing mechanism 10. The transporting stage 4 comprises a rotary encoder (not shown in the figures) in order to identify the position or the distance of the transportation stage 4. The drive arrangement can be constituted with a rack and pinion and an electrical motor or a pneumatic or hydraulic linear motion system or the like. Alternatively, the drive arrangement can also be constituted with a ball screw and a servo motor.

Although the transportation stage 4 can be movable only along the first direction a in this embodiment, the transportation stage may configured to be movable along a second direction (left and right direction) b perpendicular to the first direction a in the horizontal plane, and a third direction (up and down direction) c perpendicular to the first direction a in the vertical plane depending on factors such as the field of view of a camera. Furthermore, the transportation stage 4 may be configured to be tilted with respect to the horizontal plane in order to capture an object comprising curved surfaces.

The flat surface capturing mechanism 6 comprises a frame 14, a first position adjustment stage 20, a flat surface capturing camera 22, and an illumination unit 24. The frame 14 comprises a pair of vertical columns 16 arranged on each side of the transportation stage 4 and fixed to the base stage 3, and a horizontal beam 18 connecting the upper ends of the vertical columns 16 and arranged perpendicular to the first direction a. The first position adjustment stage 20 is attached to the horizontal beam 18 of the frame 14. The flat surface capturing camera 22 is attached to the first position adjustment stage 20.

A line scan camera, an area camera, or the like can be used as the flat surface capturing camera 22. The flat surface capturing camera 22 is oriented to capture the object 2 from the upper side of the object 2 along the third direction c. Although the flat surface capturing camera 22 is configured to capture the object 2 from the upper side of the object 2 in this embodiment, the flat surface capturing camera 22 can be configured to capture the object 2 from the underside of the object 2. Furthermore, a distance sensor can be also used instead of the flat surface capturing camera.

The first position adjustment stage 20 is movable along the second direction b. In addition, the first position adjustment stage 20 is also movable along the third direction c. Accordingly, the flat surface capturing camera 22 attached to the first position adjustment stage 20 is movable along the second direction b and the third direction c. The movement of the first position adjustment stage 20 along the second direction b and the third direction c can be carried out with any suitable means such as a pneumatic or hydraulic linear motion system. With this mechanism, positioning and focusing of the flat surface capturing camera 22 can be carried out depending on a size of the object 2 and depth of field of the flat surface capturing camera 22.

In addition, the first position adjustment stage 20 may be configured to tilt along the first direction a. Although the frame 14 of the flat surface capturing mechanism 6 is a portal frame, it may be a cantilever beam-typed frame comprising a vertical column and a horizontal beam connected to the vertical column.

The illumination unit 24 consists of two straight-typed illumination devices, and is fixed to the base stage 3. The two straight-typed illumination devices are arranged so that a longitudinal direction thereof is perpendicular to the first direction a. Furthermore, the two straight-typed illumination devices are arranged to sandwich the flat surface capturing camera 22 therebetween. The illumination unit 24 illuminates a flat surface of the object 2 from the upper side of the object 2. Although the illumination unit 24 consists of two straight-typed illumination devices in this embodiment, it may be a ring-shaped illumination device or the like arranged so as to surround a lens of the flat surface capturing camera 22. In addition, the illumination unit 24 may be configured to change an illuminating angle with respect to the object 2.

The first side surface capturing mechanism 8 is arranged on one side of the transportation stage 4 with respect to the first direction a. The first side surface capturing mechanism 8 comprises a frame (not shown in the figures) fixed to the base stage 3, a second position adjustment stage 30, a first side surface capturing camera 32, and an illumination unit 34. The second position adjustment stage 30 is attached to the frame. The first side surface capturing camera 32 is attached to the second position adjustment stage 30.

A line scan camera, an area camera, or the like can be used as the first side surface capturing camera 32. The first side surface capturing camera 32 is oriented to capture the object 2 along the second direction b from one side of the object 2. Furthermore, a distance sensor can be also used instead of the side surface capturing camera.

The second position adjustment stage 30 is movable along the second direction b. In addition, the second position adjustment stage 30 is also movable along the third direction c. Accordingly, the first side surface capturing camera 32 attached to the second position adjustment stage 30 is movable along the second direction b and the third direction c. The movement of the second position adjustment stage 30 along the second direction b and the third direction c can be carried out with any suitable means such as a pneumatic or hydraulic linear motion system. With this mechanism, positioning and focusing of the first side surface capturing camera 32 can be carried out depending on a size of the object 2 and depth of field of the first side surface capturing camera 32.

The illumination unit 34 is a ring-shaped illumination device arranged so as to surround a lens of the first side surface capturing camera 32. The illumination unit 34 illuminates a side surface of the object 2 from one side of the object 2. Although the illumination unit 34 is a ring-shaped illumination device in this embodiment, the illumination unit 34 may consist of consists of two straight-typed illumination devices sandwiching a lens of the first side surface capturing camera 32, similar to the illumination unit 24.

The second side surface capturing mechanism 9 is arranged on a side opposite to the first side surface capturing mechanism 8 with respect to the transport stage 4. The second side surface capturing mechanism 9 is offset from the first side surface capturing mechanism 8 along the first direction a. The second side surface capturing mechanism 9 comprises a frame (not shown in the figures) fixed to the base stage 3, a third position adjustment stage 36, a second side surface capturing camera 38, and an illumination unit 40. The third position adjustment stage 36 is attached to the frame. The second side surface capturing camera 38 is attached to the third position adjustment stage 36. Although the first side surface capturing mechanism 8 and second side surface capturing mechanism 9 are offset with respect to each other in this embodiment, these capturing mechanisms may also not be offset.

A line scan camera, an area camera, or the like can be used as the second side surface capturing camera 38. The first side surface capturing camera 32 is oriented to capture the object 2 along the second direction b from the side opposite to the first side capturing camera 32 of the object 2. Furthermore, a distance sensor can be also used instead of the side surface capturing camera.

The third position adjustment stage 36 is movable along the second direction b as well as the second position adjustment stage 30. In addition, the third position adjustment stage 36 is also movable along the third direction c. Accordingly, the second side surface capturing camera 38 attached to the third position adjustment stage 36 is movable along the second direction b and the third direction c. The movement of the third position adjustment stage 36 along the second direction b and the third direction c can be carried out with any suitable means such as a pneumatic or hydraulic linear motion system. With this mechanism, positioning and focusing of the second side surface capturing camera 38 can be carried out depending on a size of the object 2 and depth of field of the second side surface capturing camera 38.

The illumination unit 40 is a ring-shaped illumination device arranged so as to surround a lens of the second side surface capturing camera 38. The illumination unit 40 illuminates a side surface of the object 2 from a side of the object 2 opposite to the first side surface capturing camera 32. Although the illumination unit 40 is a ring-shaped illumination device in this embodiment, the illumination unit 40 may consist of two straight-typed illumination devices sandwiching a lens of the second side surface capturing camera 38, similar to the illumination unit 24.

Figure 4 is an enlarged figure showing the first side surface capturing mechanism 8 or the second side surface capturing mechanism 9 and the object 2. In this embodiment, the side surface capturing mechanism comprises an optical component 42. This optical component 42 is arranged between the side surface capturing mechanism and the object 2. The optical component 42 is a prism or a mirror. With this configuration, it is possible to simultaneously capture images of a plurality of surfaces of the object 2 with one camera and project the images of the plurality of surfaces within one field of view.

As shown in FIG. 5, since the object 2 has a sheet shape, the dimension along the third direction c of the object 2 is extremely smaller than the dimensions along the first direction a and the second direction b. Due to this, the side surface of the object 2 is smaller than the field of view fh along the third direction c of the field of view f of the side surface capturing camera. Accordingly, a blank portion in which nothing is captured appears remarkably in the captured image of the side surface capturing camera. By arranging the optical component 42 between the side surface capturing camera and the object 2, it is possible to project images of a plurality of surfaces of the object 2 in a blank portion. Thereby, it is possible to take images of a plurality of surfaces in one step.

Although each one of the flat surface capturing camera 6, the first side surface capturing camera 32, and the second side surface capturing camera 38 is provided in this embodiment, a plurality of the flat surface capturing camera 6, the first side surface capturing camera 32, and the second side surface capturing camera 38 can be provided along the first direction a. At this time, by changing the optical conditions such as the type of the illumination unit and the camera, it is possible to carry out capturing in a plurality of optical conditions for one surface in one step.

The reversing mechanism 10 comprises a telescopic arm 44, reversing device 46, and a gripping portion 48. The reversing device 46 is attached to the telescopic arm 44. The gripping portion 48 is attached to the reversing device 46. The reversing device 46 is reversible around a reversal axis r. With this configuration, the gripping portion 48 reverses as the reversing device 46 reverses. The reversal axis r makes an acute angle, preferably 45 degrees with the first direction a horizontal plane including the reversal axis r. The arm 44 is telescopic along a fourth direction d parallel to the reversal axis r. The arm 44 is further movable along the third direction c. The arm 44 may be a robot arm with a multi-axial joint.

The gripping portion 48 comprises two

gripping claws

48a, 48b. The gripping

claws

48a, 48b are symmetrically arranged with respect to a plane including the reversal axis r, preferably symmetrically arranged with respect to the horizontal plane including the reversal axis r. That is, the gripping

claws

48a, 48b are vertically arranged along the third direction c with the reversal axis r therebetween. The gripping

claws

48a, 48b are movable along the third direction c between an open position, in which the

gripping claws

48a, 48b are away from each other, and a close position, in which the

gripping claws

48a, 48b are close to each other. The gripping

claws

48a, 48b may be configured by using any suitable arrangement such as a pneumatic hand chuck.

Two

gripping claws

48a, 48b can grip the object 2 therebetween. In order to avoid damage and dropping of the object 2, a protective member such as a rubber sheet may be attached to the gripping surfaces of the

gripping claws

48a, 48b, which are in contact with the object 2. The gripping portion 48 includes a pressure sensor for measuring the gripping pressure of the object 2, and the gripping pressure of the object 2 may be adjusted.

The visual inspection apparatus 1 may be connected to an external computer device (not shown in the figures) . The visual inspection apparatus 1 can transmit the image data obtained from the flat surface capturing camera 22, first side surface capturing camera 32, and second side surface capturing camera 38 to the external computer device. The image data transmitted can be subjected to necessary image processing by the external computer device. In addition, the external computer device can also process the data obtained by the distance sensors. In addition, the visual inspection apparatus 1 may be configured to adjust factors such as transportation speed of the transportation stage 4 and position of the cameras via the external computer device.

Next, an inspection method using the visual inspection apparatus 1 according to the embodiment of the present invention will be described. The object 2 to be inspected is a smartphone as an example.

In the initial state shown in FIG. 7A, the transportation stage 4 is stationary at the mounting position 26. At this position, the smartphone that is the object 2 to be inspected is placed on the rest portion 12 of the transportation stage 4. The smartphone is placed so that the front surface 201 is facing upward (the direction facing the flat surface capturing camera 22) and the longer side surfaces 203, 204 are parallel to the first direction a. Here, the surface provided with the display screen of the smartphone is defined as the front surface 201. The smartphone may be placed on the rest portion 12 in a different arrangement, for example, with the back surface 202 facing upward. The smartphone may be manually placed on the rest portion 12 by an operator, or may be automatically placed on the rest portion 12 using a robot arm or the like.

After the smartphone is placed on the rest portion 12, the smartphone is fixed on the rest portion 12 by means of a vacuum absorbing pad. At this time, a predetermined clearance is formed between the surface (back surface) of the smartphone in contact with the absorbing pad and the upper surface of the transportation stage 4.

Depending on the external dimensions of the placed smartphone, the first position adjustment stage 20, the second position adjustment stage 30, and the third position adjustment stage 36 respectively adjust the capturing positions and focus of the flat surface capturing camera 22, the first side surface capturing camera 32, and the second side surface capturing camera 38. These adjustments can be performed based on the external dimension data of the smartphone preliminarily input to the external computer device, or can be performed by the operator directly inputting data during work.

After the positions of the cameras are adjusted, the transportation stage 4 moves from the mounting position 26 toward the reversing position 28 at a predetermined speed.

While being transported, the exterior of the smartphone is captured from three directions by the cameras. In this embodiment, the front surface 201 and both of the longer side surfaces 203, 204 of the smartphone are captured in the forward path from the mounting position 26 to the reversing position 28. The exterior is continuously captured without stopping the transportation stage 4. Alternatively, the smartphone may be divided into a plurality of areas and each area may be captured with the transportation stage 4 being stopped. After the capture is completed, the data captured are transmitted to the external computer device for image analysis.

As shown in FIG. 7B, when the transfer stage 4 reaches the reversing position 28, the transfer stage 4 stops. Next, the arm 44 of the reversing mechanism 10 extends and advances the

gripping claws

48a, 48b toward the smartphone along the fourth direction. The gripping

claws

48a, 48b are initially arranged at a height such that the first gripping claw 48a is disposed on the upper side of the smartphone and the second gripping claw 48b is inserted into the clearance between the lower surface of the smartphone and the upper surface of the transfer stage 4. At this time, the gripping

claws

48a, 48b are in the open position. When the

gripping claws

48a, 48b reach a predetermined position, as shown in FIG. 7C, the extension of the arm 44 stops, and the advance of the

gripping claws

48a, 48b is stopped.

After the

gripping claws

48a, 48b are stopped and arranged at the predetermined positions, the gripping

claws

48a, 48b move toward the closed position. Even after the

gripping claws

48a, 48b contact the smartphone, the gripping

claws

48a, 48b further move toward the closed position. This causes the gripping pressure to increase, and the increase of the gripping pressure is detected by the pressure sensor. When the gripping pressure reaches a predetermined threshold, the gripping

claws

48a, 48b are stopped.

Next, the rest portion 12 dissolves the vacuum state. Thereby, the smartphone is released from the state of being fixed to the rest portion 12 and can be removed from the rest portion 12. Then, the arm 44 rises along the third direction while the

gripping claws

48a, 48b grip the smartphone.

When the reversing mechanism 10 reaches a predetermined height, the reversing device 46 reverses by 180° about the reversal axis r. Accordingly, as shown in FIG. 6, the smartphone gripped by the gripping

claws

48a, 48b is reversed by 180° around the reversal axis r. Since the reversal axis r is inclined by 45° with respect to the first direction a, as shown in FIG. 7D, the back surface 202 is directed upward and the shorter side surfaces 205, 206 are arranged so as to be parallel to the first direction a after the smartphone is reversed by 180°.

After the smartphone is reversed by 180°, the arm 44 is lowered. As the arm 44 is lowered, the smartphone held by the gripping

claws

48a, 48b is also lowered. The lowered smartphone is placed again on the rest portion 12. After the smartphone is placed on the rest portion 12, the smartphone is fixed again on the rest portion 12 by means of the vacuum absorbing pad.

After the smartphone is fixed, the gripping

claws

48a, 48b move toward the open position to release the smartphone. After the smartphone is released, the arm 44 retracts along the fourth direction d. As shown in FIG. 7E, as the arm 44 retracts, the gripping

claws

48a, 48b also move away from the smartphone.

Depending on the change in the arrangement of the smartphone, the first position adjustment stage 20, the second position adjustment stage 30, and the third position adjustment stage 36 respectively move the flat surface capturing camera 22, the first side surface capturing camera 32, and the second side surface capturing camera 38 to adjust the capturing positions and focus thereof.

After the positions of the cameras are adjusted, the transportation stage 4 moves from the reversing position 28 toward the mounting position 26 at a predetermined speed. While being conveyed, the exterior of the smartphone is captured from three directions by the cameras. In this embodiment, on the return path from the reversing position 28 to the mounting position 26, the back surface and both of the shorter side surfaces of the smartphone are captured. The exterior of the smartphone is continuously captured without stopping the stage 4. Alternatively, the smartphone may be divided into a plurality of areas and each area may be captured with the transportation stage 4 being stopped. After the capture is completed, the data captured are transmitted to the external computer device for image analysis.

As shown in FIG. 7F, when the transportation stage 4 reaches the mounting position 26, the transportation stage 4 stops. After the transportation stage 4 stops, the rest portion 12 dissolves the vacuum state. Thereby, the smartphone is released from the state of being fixed to the rest portion 12 and can be removed from the placement unit 12. Removal of the smartphone from the visual inspection apparatus 1 may be manually performed by an operator, or may be automatically performed using a robot arm or the like.

When the side surfaces are formed of a curved surface, or when it is necessary to observe the side surfaces from directions different from the normal direction, the object 2 can be observed on a plurality of surfaces by disposing the optical component 42 between the object 2 and the first side surface capturing camera 32 and the second side surface capturing camera 38 while the transfer stage 4 makes one round trip.

It should be understood that the foregoing embodiments are intended to describe technical solutions according to the present invention rather than limiting the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that they may further improve the technical solutions described in the previous embodiments or may be replaced with the equivalent technical solutions without departing from the concept and scope of the technical solutions of the embodiments of the present invention.

[Explanation of Reference]

1 Visual Inspection Apparatus

2 Object to be inspected

3 Base Stage

4 Transportation Stage

6 Flat Surface Capturing Mechanism

8 First Side Surface Capturing Mechanism

9 Second Side Surface Capturing Mechanism

10 Reversing Mechanism

12 Rest Portion

14 Frame

16 Vertical Column

20 First Position Adjustment Stage

22 Flat Surface Capturing Camera

24 Illumination Unit

26 Mounting Position

28 Reversing Position

30 Second Position Adjustment Stage

32 First Side Surface Capturing Camera

34 Illumination Unit

36 Third Position Adjustment Stage

38 Second Side Surface Capturing Camera

40 Illumination Unit

42 Optical Component

44 Telescopic Arm

46 Reversing Device

48 Gripping Portion

48a, 48b Gripping Claw

201 Front Surface

202 Back Surface

203, 204 Longer Side Surface

205, 206 Shorter Side Surfaces

Claims

A visual inspection apparatus (1) for inspecting an object (2) to be inspected having a sheet shape, which comprises a pair of flat surfaces (201, 202) , a pair of first side surfaces (203, 204) , and a pair of second side surfaces (205, 206) , the visual inspection apparatus comprising:

a transportation stage (4) for placing and transporting the object (2) , comprising a rest portion (12) for fixing the object (2) with respect to the transportation stage (4) and moving between a first position (26) and a second position (28) along a first direction (a) in the horizontal plane;

a flat surface capturing mechanism (6) comprising a flat surface capturing camera (22) for capturing an image of the object (2) along a third direction (c) perpendicular to the first direction (a) in the vertical plane;

a first side surface capturing mechanism (8) comprising a first side surface capturing camera (32) for capturing the object (2) from one side along a second direction (b) perpendicular to the first direction (a) in the horizontal plane;

a second side surface capturing mechanism (9) comprising a second side surface capturing camera (38) for capturing the object (2) from the other side along the second direction (b) ; and

a reversing mechanism (10) for reversing the object (2) by 180 degrees at the second position (28) around a reversal axis (r) , comprising a gripping portion (48) for gripping the object (2) , wherein the reversal axis (r) forms an angle of 45 degrees with the first direction (a) in the horizontal plane including the reversal axis (r) ,

wherein when the transportation stage (4) moves from the first position (26) to the second position (28) , the flat surface capturing mechanism (6) , the first side surface capturing mechanism (8) , and the second side surface capturing mechanism (9) capture the one flat surface and the pair of first side surfaces, and wherein when the transportation stage (4) moves from the second position (28) to the first position (26) , the flat surface capturing mechanism (6) , the first side surface capturing mechanism (8) , and the second side surface capturing mechanism (9) capture the other flat surface and the pair of second side surfaces.
A visual inspection apparatus (1) according to claim 1, wherein an optical component (42) is arranged between the object (2) and the first and/or the second side surface capturing mechanism so that it enables simultaneous multi-surface capturing of the side surface of the object (2) .
A visual inspection apparatus (1) according to claim 1 or 2, wherein the flat surface capturing mechanism (6) comprises a first position adjustment stage (22) capable of moving the flat surface capturing camera (22) along the second direction (b) and the third direction (c) .
A visual inspection apparatus (1) according to any one of claims 1 to 3, wherein the first side surface capturing mechanism (8) comprises a second position adjustment stage (30) capable of moving the first side surface capturing camera (32) along the second direction (b) and the third direction (c) , and wherein the second side surface capturing mechanism (9) comprises a third position adjusting stage (36) capable of moving the second side surface capturing camera (38) along the second direction (b) and the third direction (c) .
A visual inspection apparatus (1) according to any one of claims 1 to 4, wherein the flat surface capturing mechanism (6) , the first side surface capturing mechanism (8) , and the second side surface capturing mechanism (9) are arranged along the first direction (a) .
A visual inspection apparatus (1) according to any one of claims 1 to 5, wherein the reversing mechanism (10) comprises an arm (44) for forwarding or retracting the gripping portion (48) with respect to the object (2) .
A visual inspection apparatus (1) according to any one of claims 1 to 6, wherein distance sensors are used instead of the flat surface capturing camera (22) , the first side surface capturing camera (32) , and the second side surface capturing camera (38) .
A visual inspection apparatus (1) according to any one of claims 1 to 6, wherein the visual inspection apparatus (1) is connected to an external computer device and transmits the data to the external computer device to process the data of the object (2) , which is captured by the capturing mechanisms.
A visual inspection method for inspecting an object (2) to be inspected having a sheet shape, which comprises a pair of flat surfaces (201, 202) , a pair of first side surfaces (203, 204) , and a pair of second side surfaces (205, 206) , the visual inspection apparatus comprising steps of:

resting and fixing the object (2) on a rest portion (12) of a transportation stage (4) positioned at a first position (26) ;

moving the transportation stage (4) from the first position (26) to a second position (28) along a first direction (a) in the horizontal plane, wherein during the movement, a flat surface capturing mechanism (6) captures the one flat surface along a third direction (c) perpendicular to the first direction (a) in the vertical plane, wherein the first side surface capturing mechanism (8) captures one first side surface from one side of a second direction (b) perpendicular to the first direction (a) in the horizontal plane, and wherein the second side surface capturing mechanism (9) captures the other first side surface from the other side of a second direction (b) ;

reversing the object (2) by 180 degrees around a reversal axis (r) at the second position (28) , wherein the reversal axis (r) forms 45 degrees with the first direction (a) in the horizontal plane including the reversal axis (r) ;

moving the transportation stage (4) from the second position (28) to the first position (26) along a first direction (a) in the horizontal plane, wherein during the movement, a flat surface capturing mechanism (6) captures the other flat surface along a third direction (c) , wherein the first side surface capturing mechanism (8) captures one second side surface from one side of a second direction (b) , and wherein the second side surface capturing mechanism (9) captures the other second side surface from the other side of a second direction (b) ; and

removing the object (2) from the transportation stage (4) which has reached the first position (26) .
A visual inspection method according to claim 9, wherein an optical component (42) is arranged between the object (2) and the first and/or the second side surface capturing mechanism so that it enables simultaneous multi-plane capturing of the side surface of the object (2) .
A visual inspection method according to claim 9 or 10, wherein the capturing is carried out without stopping the transportation stage (4) .
A visual inspection method according to claim 9 or 10, wherein the capturing is carried out by dividing the object (2) into a plurality of areas and stopping the transportation stage (4) for each area.
A visual inspection method according to any one of claims 9 to 12, wherein distance sensors are used instead of the flat surface capturing camera (22) , the first side surface capturing camera (32) , and the second side surface capturing camera (38) .