Appearance inspection apparatus of workpiece and appearance inspection method of workpiece

[0053] The first embodiment

[0054] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 to Figure 9 It is a figure which shows the 1st Embodiment of the appearance inspection apparatus of a workpiece|work and the appearance inspection method of a workpiece|work which concerns on this invention.

[0055] First, pass figure 2 Let's explain the workpiece inspected by the workpiece visual inspection device.

[0056] in figure 2 Among them, the work W, which is a chip component such as a capacitor and/or a resistor, has a hexahedral shape, and has a main body Wd made of an insulator and electrodes Wa and Wb made of conductors formed on both ends of the main body Wd in the longitudinal direction. In the case of performing an appearance inspection of the workpiece W, the workpiece W is placed on a conveyor table 2 described later, and the conveyor table 2 is directed figure 2 Rotate in the direction of arrow Z to convey the workpiece W. Furthermore, the imaging unit 20 photographs the side surface on the opposite side of the paper from the direction of arrow A, the side before the paper from the direction of arrow B, the upper surface from the direction of arrow C, the lower surface from the direction of arrow D, The front surface is photographed in the direction of arrow E, and the rear surface is photographed in the direction of arrow F. At this time, by using the transparent transport table 2 made of glass, it is possible to image all six surfaces of the workpiece W while the workpiece W is placed.

[0057] Next, the appearance inspection device of the workpiece will be explained. Such as figure 1 and image 3 As shown, the workpiece appearance inspection device 30 includes: a linear feeder 1 that conveys a workpiece W; and a workpiece W is transferred from the linear feeder 1 to a transfer point 4x, and the workpiece W is placed on the workpiece A circular conveying table 2 made of a transparent body conveyed on the conveying arc 5; a transfer aligning unit 21 that transfers the workpiece W from the linear feeder 1 to the conveying table 2 to make it aligned; arranged on the conveying table The charging unit 6A that functions as a holding unit below the lower surface of the conveying table 2 and charging the lower surface of the conveying table 2 to hold the workpiece W placed on the conveying table 2; and photographing the six faces of the workpiece W on the conveying table 2 The shooting unit 20.

[0058] Among them, the transfer and alignment unit 21 has a non-vibration section 4 provided between the linear feeder 1 and the conveying table 2 and an alignment guide 7 provided on the downstream side of the non-vibration section 4 for aligning the workpieces W. The alignment guide The lead 7 includes a guide surface 7a for aligning the work W in a row. The guide surface 7a is linear in a plan view (viewed from above).

[0059] In addition, the imaging unit 20 has a side camera portion 8, an inner surface camera portion 9, an upper surface camera portion 10, a lower surface camera portion 11, a front surface camera portion 12, and a rear surface camera portion 13 as described later.

[0060] Secondly, further through Figure 1 to Figure 4 The components of the work appearance inspection device 30 will be described.

[0061] here, figure 1 So figure 2 The workpiece W of the shape shown is a plan view of the appearance inspection apparatus of the target workpiece, image 3 Yes figure 1 An enlarged top view of the area S enclosed by the dotted line, Figure 4 Is viewed from the direction of arrow Y figure 1 Perspective view of middle area S.

[0062] in figure 1 In this case, the linear linear feeder 1 is vibrated by a drive source not shown, and the workpieces W fed into a feeder not shown on the upstream side of the linear feeder 1 are aligned in a row, and the vibration direction The workpiece W is conveyed in the direction of the arrow N.

[0063] The conveying table 2 provided below the linear feeder 1 is made of transparent glass and installed horizontally, and is driven clockwise by a drive source (not shown) centered on the shaft 3 ( figure 1 The arrow X direction) rotate. Such as Figure 4 As shown, the linear feeder 1 descends with a slight slope toward the conveying table 2, and has a non-vibration part 4 with the same tilt and vibration as the linear feeder 1 at its downstream end, and is connected with the conveying table 2 with a slight gap . In this way, the workpiece W is gradually lowered from the linear feeder 1 via the vibration-free part 4 and transferred to the transport table 2.

[0064] Near the outer edge of the upper surface of the conveyor 2, such as figure 1 As shown by the one-dot chain line, the workpiece conveying arc 5 is formed as an arc centered on the rotating shaft 3. After the workpiece W is transferred from the vibration-free part 4 to the conveying table 2, it passes through the alignment guide described later. The lead 7 is aligned on the workpiece conveying arc 5. Here, the workpiece conveying arc 5 is an assumed target position for aligning the workpieces W, and any mark capable of visually identifying the workpiece conveying arc 5 is not marked on the upper surface of the conveying table 2.

[0065] In addition, the charging unit 6A functions as a holding unit that holds the workpiece W placed on the transport table 2. The charging unit 6A is composed of an ionizer 6 installed slightly in front of the vibration-free part 4, and the ionizer 6 is installed directly below the transport table 2 to eject positive ions (hereinafter referred to as Is “charge”) to positively charge the lower surface of the transport table 2.

[0066] In addition, in each of the above-mentioned components, the non-vibration part 4 and the guide body 7 having the guide surface 7a constitute the transfer alignment unit 21.

[0067] In addition, in image 3 Among them, the alignment guides 7 having the linear guide surface 7a are provided directly above the outer edge portion of the conveying table 2 with a slight gap with the conveying table 2. in image 3 Here, the straight line connecting the transfer point 4x and the rotating shaft 3 of the conveying table 2 is represented as a broken line K.

[0068] Such as image 3 As shown, the entire column of guide bodies 7 are arranged such that the angle α formed by the guide surface 7a and the dashed line K is an acute angle of 75 degrees to 88 degrees, and the guide surface 7a is located in a conveying direction closer to the workpiece W than the transfer point 4x The confluence point 7x of the downstream workpiece conveying arc 5 becomes the tangent of the workpiece conveying arc 5. That is, when the straight line connecting the junction 7x and the rotating shaft 3 of the conveying table 2 is represented by the broken line L, the angle β formed by the broken line L and the guide surface 7a is 90°.

[0069] In addition, such as figure 1 As shown, on the downstream side of the vibration-free portion 4, along the rotation direction of the conveying table 2, a side camera portion 8, an inner surface camera portion 9, an upper surface camera portion 10, a lower surface camera portion 11, and a front surface constituting the imaging unit 20 are provided. The surface camera section 12 and the rear surface camera section 13. The photographing unit 20 can separately photograph the workpiece W on the workpiece conveying arc 5 figure 2 Each surface of the workpiece W shown by the middle arrows A to F is subject to visual inspection. at this time, figure 2 The conveying direction of the workpiece W indicated by the middle arrow Z and figure 1 The rotation direction X of the conveying table 2 in the middle is the same.

[0070] Specifically, for the workpiece W, the side camera section 8 photographs the side surface A on the opposite side of the paper surface, the inner surface camera section 9 photographs the side surface B in front of the paper surface, the upper surface camera section 10 photographs the upper surface C, and the lower surface camera section 11 photographs the lower surface. For surface D, the front surface camera section 12 photographs the front surface E, and the rear surface camera section 13 photographs the rear surface F.

[0071] Again, such as figure 1 As shown, a discharge unit 14 as a discharge unit is provided on the downstream side from the imaging unit 10 in the rotation direction of the transport table 2. The work W on which the appearance inspection has been completed is discharged from the work conveying arc by the discharge unit 14 into a storage box not shown in accordance with the result of the appearance inspection.

[0072] Next, a detailed description will be given of a method for inspecting the appearance of a workpiece using the apparatus for inspecting the appearance of a workpiece having this configuration.

[0073] in figure 1 In this case, the workpiece W is fed into a feeder not shown on the upstream side of the linear feeder 1, and the workpiece W placed in the feeder is vibrated by the linear feeder 1 using a drive source not shown. And the whole column is one column, to figure 1 The direction of the arrow N is sequentially conveyed. At this time, align the workpiece W so that the longer direction coincides with the conveying direction, figure 2 The arrow Z in the middle becomes the conveying direction of the workpiece W. which is, figure 2 The direction of arrow Z in figure 1 The direction of the arrow N is the same.

[0074] Secondly, through Figure 4 The function of the linear feeder 1 will be described in detail. Figure 4 It is a diagram showing the state of the workpiece W conveyed by the linear feeder 1, viewed from the direction of arrow Y figure 1 A perspective view of the area S enclosed by a dotted line in the middle. In order to facilitate the observation of the condition of the workpiece W on the conveyor 2, Figure 4 It becomes a perspective view showing the position of the alignment guide 7 with a broken line. In addition, for the workpiece W, the workpiece on each constituent part is represented as the workpiece W 0 ~W 6 , The general workpiece is represented as a workpiece W at any place.

[0075] Such as Figure 4 As shown, the linear feeder 1 is slightly inclined toward the conveying table 2 at its lower position, and the workpiece W that is pushed by the subsequent workpiece W due to the vibration of the linear feeder 1, such as W 0 It shows that it descends continuously toward the conveyor table 2 in the front-rear direction. The linear feeder 1 vibrates, so if the linear feeder 1 is brought close to the upper position of the conveyor table 2 when the workpiece W is transferred from the linear feeder 1 to the conveyor table 2, the linear feeder 1 and the conveyor Station 2 may touch. To prevent this, between the downstream end of the linear feeder 1 and the conveying table 2, a vibration-free part 4 that does not vibrate is provided.

[0076] In addition, it should also be considered that the fluctuation of the conveying speed of the workpiece W in the linear feeder 1 caused by the fluctuation of the vibration of the linear feeder 1 is caused by the existence of no vibration between the linear feeder 1 and the conveying table 2. Section 4 can make the conveying speed uniform.

[0077] However, the non-vibration part 4 has the same inclination as the linear feeder 1 and has a slight gap with the upper surface of the conveying table 2. The workpiece W on the vibration-free part 4 is pushed forward by the subsequent workpiece in the same way as the linear feeder 1, as W 0 As shown, it descends toward the conveying table 2 in a continuous front and rear direction.

[0078] Moreover, the workpiece W that has reached the downstream end of the vibration-free part 4 1 Workpiece W located directly behind 0 Is pushed, and is transferred to the transfer point 4x on the conveying table 2, and later by the rotation of the conveying table 2 Figure 4 The direction of arrow X is conveyed. Here, if the length of the non-vibration portion 4 is too short, it is difficult to make the conveying speed uniform, and if the length is too long, the workpiece W may stop in the middle. In the embodiment of the present invention, the length of the non-vibration portion 4 is 8 times the size of the workpiece in the longitudinal direction, and the conveying speed of the workpiece W can be made uniform without stopping the workpiece W.

[0079] Furthermore, as described above, an ionizer 6 is provided on the lower side of the transport table 2, and the ionizer 6 ejects a positive charge toward the lower surface of the transport table 2 to positively charge the lower surface of the transport table 2. in Figure 4 In, the positive charge is schematically represented by +. By positively charging the lower surface of the conveyor table 2 as described above, the workpiece W transferred to the transfer point 4x is attracted to the upper surface of the conveyor table 2.

[0080] Secondly, through Figure 5 to Figure 7 The suction effect of the workpiece W on the conveying table 2 will be explained.

[0081] among them, Image 6 (A) and (b) are explanatory diagrams showing the principle of electrostatic induction. in Image 6 In (a), the electrode Wa at one end of the workpiece W in the longitudinal direction is shown. The electrode Wa is composed of a conductive body, under normal conditions, such as Image 6 As shown in (a), there are positive charges represented by "+" and negative charges represented by "-" at random positions inside. in Image 6 (B) shows the situation when the positive charge approaches the electrode Wa from the left.

[0082] Here, the positively charged charged body is brought close to T. At this time, the negative charges in the electrode Wa are attracted by the positive charges in the charged body T, and the negative charges are concentrated on the left WaL side of the electrode Wa close to the charged body T. In addition, the positive charge in the electrode Wa repels the positive charge in the charged body T, and is concentrated on the right side WaR of the electrode Wa far from the charged body T. At this time, negative charges appear on the WaL side on the left, and positive charges appear on the WaR side on the right. Furthermore, the electrode Wa is composed of a charged body, and the internal charge can move freely. Therefore, the Image 6 In (b), the electric charge does not exist in the part between the left WaL and the right WaR of the electrode Wa. This phenomenon is called electrostatic induction.

[0083] In addition, electrostatic induction acts between the negative charge concentrated on the WaL side of the left side of the electrode Wa and the positive charge in the charged body T Image 6 (B) Gravity shown by arrow G. Therefore, the electrode Wa is attracted by the charged body T. If the charged body T moves away from the electrode Wa, the charge in the electrode Wa returns to Image 6 (A) State. The same applies to the electrode Wb.

[0084] Figure 7 (A) and (b) are explanatory diagrams showing the principle of dielectric polarization. among them, Figure 7 (A) shows the main body Wd of the workpiece W located at the center in the longitudinal direction. The main body Wd is an insulator, under normal conditions, such as Figure 7 As shown in (a), there are molecules (a dotted ellipse) in which the positive charge represented by "+" and the negative charge represented by "-" are grouped together at random positions inside.

[0085] in Figure 7 (B) shows the situation when the positive charge approaches the subject Wd from the left. Here, the positively charged charged body T is brought close. At this time, the negative charges in the main body Wd are attracted by the positive charges in the charged body T, and the positive charges in the main body Wd and the positive charges in the charged body T repel. Therefore, the orientation of the molecules in the main body Wd is aligned such that the left WdL side of the main body Wd close to the charged body T is negatively charged, and the right side WdR of the main body Wd away from the charged body T is positively charged.

[0086] Such as Figure 7 As shown in (b), negative charges appear on the WdL side of the left side of the main body Wd, and positive charges appear on the WdR side of the right side. Furthermore, the main body Wd is an insulator, so the internal charges cannot move freely, and the molecules are aligned in a certain direction between the left WdL and the right WdR. This phenomenon is called dielectric polarization. In addition, the dielectric polarization acts between the negative charge appearing on the WaL side of the left side of the main body Wd and the positive charge in the charged body T Figure 7 (B) Gravity shown by arrow G. Therefore, the main body Wd is attracted by the charged body T. If the charged body T is far away from the body Wd, the charge in the body Wd returns to Figure 7 (A) State.

[0087] Secondly, through Figure 5 It shows the state where the workpiece W transferred to the 4x is attracted to the upper surface of the transport table 2 by electrostatic induction and dielectric polarization. in Figure 5 Among them, the lower surface of the conveying table 2 is positively charged by the action of the ionizer 6. The glass that is the material of the transport table 2 is an insulator. Therefore, the above-mentioned dielectric polarization occurs due to the positive charge present on the lower surface of the transport table 2. In the interior of the transport table 2, negative charges appear on the lower surface side and on the upper surface side. A positive charge appears. In addition, similarly, for the workpiece W that is transferred from the vibration-free part 4 to the transfer point 4x on the conveyor table 2 2 , The electrodes Wa and Wb are electrostatically induced, and the main body Wd is polarized by the dielectric, and negative charges appear on the lower surface side, and positive charges appear on the upper surface side.

[0088] in Figure 5 In this, between the negative charges appearing on the bottom surface of the electrodes Wa and Wb and the main body Wd and the positive charges appearing on the bottom surface of the transport table 2, the electrostatic attraction force G shown by the arrow acts, so that the workpiece W 2 It is adsorbed on the upper surface of the conveyor 2. At this time, only through the workpiece W 2 The lower surface of the carrier 2 and the lower surface of the conveying table 2 are charged by electrostatic induction or dielectric polarization, so there will be no charging caused by the movement of the charges. Therefore, neutralization of the charge does not occur during adsorption, and the adsorption force does not decrease after adsorption. In this way, the workpiece W 2 It is transported in the direction of arrow X by the rotation of the transport table 2 in a state of being sucked on the upper surface of the transport table 2.

[0089] Next, the workpiece W transferred from the vibration-free part 4 to the transfer point 4x on the conveying table 2 is used as the workpiece W 2 It is shown that it is conveyed in the direction of arrow X by the rotation of the conveying table 2 in a state of being sucked to the conveying table 2.

[0090] In this case, the conveying speed generated by the rotation of the conveying table 2 is higher than the conveying speed generated by the linear feeder 1 and the vibration-free part 4, and between the workpieces on the conveying table 2 (for example, W 2 And W 3 Between) has an interval. By having a gap between the workpieces on the conveying table 2 as described above, figure 1 The front surface of the camera section 12 shooting figure 2 The front surface E of the workpiece W shown, figure 1 13 shooting on the rear surface of the camera figure 2 When the rear surface F of the workpiece W is shown, it is possible to reliably image the entire surface.

[0091] That is, if the workpiece W is transferred from the transfer point 4x to the transfer table 2 and transported, the workpiece W is electrostatically attracted to image 3 The state in the interval P, such as W 2 →W 3 →W 4 Accelerate so quickly to the conveying speed of the conveying table 2, and the interval between the workpieces in the section Q expands to, for example, W 4 With W 5 Between.

[0092] At this time, there is a slight gap between the non-vibration part 4 and the conveying table 2, and the conveying speed generated by the rotation of the conveying table 2 is greater than the conveying speed generated by the non-vibrating part 4, so the workpiece W 2 If it is not sufficiently attracted to the conveyor table 2, the workpiece W may be transferred from the non-vibration part 4 to the transfer point 4x on the conveyor table 2 2 There will be small jumps. In this case, since the jump generated in the workpiece W fluctuates for each workpiece W, the interval between the workpieces W on the transport table 2 after acceleration fluctuates. In contrast, according to the present invention, since the workpiece W 2 It is sufficiently adsorbed on the transport table 2 so that the workpiece W is transferred from the non-vibration part 4 to the transfer point 4x on the transport table 2 2 There is no jumping, but it is fixed on the conveyor 2. Therefore, the interval between the accelerated workpieces W can be kept substantially constant.

[0093] However, just above the transfer point 4x of the outer edge of the transport table 2, the alignment guide 7 having the linear guide surface 7a and the transport table 2 are provided with a slight gap. As mentioned above, in image 3 When the straight line connecting the transfer point 4x and the rotating shaft 3 is set as the dashed line K, the alignment guide 7 is set such that the angle α formed by the guiding surface 7a and the dashed line K is an acute angle, and the guiding surface 7a is located at The confluence point 7x in the downstream direction of the transfer point 4x becomes a tangent to the workpiece conveying arc 5. That is, when the dashed line L represents the straight line connecting the junction 7x and the rotating shaft 3, the angle β formed by the dashed line L and the guide surface 7a is 90°. Therefore, the transfer point 4x is located on the outer edge side of the conveying table 2 with respect to the workpiece conveying arc 5. Therefore, the conveyance direction (arrow X) of the workpiece W transferred to the transfer point 4x becomes the direction toward the guide surface 7a, and the slight difference in the posture of the workpiece W at the transfer point 4x can be corrected to be the same.

[0094] Secondly, use Picture 9 (A) and (b) to illustrate the alignment effect of the alignment guide 7.

[0095] here, Picture 9 (A) shows the workpiece W transferred to the transfer point 4x 2E1 The posture is slightly to the left relative to the correct direction. The position of the transfer point 4x is on the outer edge side of the conveying table 2 with respect to the workpiece conveying arc 5, at Picture 9 (A) The rotation direction of the conveying table 2 indicated by the arrow X becomes the same direction as the trajectory of the workpiece conveying arc 5, and the workpiece W 2E1 The conveying direction of is the direction toward the guide surface 7a. Therefore, the workpiece W 2E1 In such as workpiece W 2E2 After abutting on the guide surface 7a in this way, it is pressed by the guide surface 7a. At this time, the workpiece W 2E1 It is attracted to the glass table 2 with a force stronger than the frictional force acting on the guide surface 7a, so even in the state of being pressed by the guide surface 7a, it follows the shape of the guide surface 7a without decelerating Was transported.

[0096] Picture 9 (B) shows the workpiece W transferred to the transfer point 4x 2E3 The posture is slightly to the right relative to the correct direction. In this case, the workpiece W 2E3 The conveying direction also becomes the direction toward the guide surface 7a, and the workpiece W 2E3 In such as workpiece W 2E4 After abutting against the guiding surface 7a, it is pushed by the guiding surface 7a, as W 2 In that way, it is conveyed in a shape along the guide surface 7a. By the action of the suction and guide surface 7a formed by the electric charge existing on the lower surface of the transport table 2 as described above, it is possible to perform high-precision positioning so that the distance between the workpieces W on the transport table 2 is substantially constant and unified. Make the posture with respect to the conveying direction constant.

[0097] However, as described above, the conveying speed formed by the rotation of the conveying table 2 is greater than the conveying speed formed by the linear feeder 1 and the vibration-free part 4, so the positioned workpiece W is image 3 In the state of being electrostatically adsorbed in the interval P, such as W 2 →W 3 →W 4 As soon as the speed is accelerated up to the conveying speed formed by the rotation of the conveying table 2, the interval between the workpieces in the section Q is expanded to, for example, W 4 And W 5 Between. Moreover, the workpiece W 5 As in the section P, it is conveyed while being pushed onto the guide surface 7a, and gradually approaches the workpiece conveying arc 5. Furthermore, the workpiece W that has reached the merging point 7x where the guide surface 7a contacts the workpiece conveying arc 5 6 The conveying direction is consistent with the direction of the workpiece conveying arc 5 in the section R, and the workpiece W 6 It is conveyed in the direction away from the guide surface 7a. That is, from the positive charge existing on the lower surface of the transport table 2 to the workpiece W on the transport table 2 6 Acting electrostatic adsorption force, so the workpiece W 6 It is moved away from the guide surface 7 a while being attracted to the conveying table 2, and then conveyed in a state in which the workpiece conveying arc 5 is placed in a row.

[0098] In addition, as mentioned above, in image 3 The transfer point 4x of the outer edge of the middle conveying table 2 is directly above, and the alignment guide 7 and the conveying table 2 are provided with a slight gap. As image 3 L line direction view, in Figure 16 The middle indicates the entire row of guides 7 and the transport table 2 near the transfer point 4x.

[0099] in Figure 16 In, workpiece W 2 It is a workpiece that has been transferred from the vibration-free part 4 to the transfer point 4x on the transfer table 2 and immediately after the transfer is started by the rotation of the transfer table 2. As mentioned above, the workpiece W 2 In a state of being electrostatically attracted to the upper surface of the conveying table 2, it is conveyed in a shape along the guide surface 7 a by the aligning action of the aligning guide 7. In this case, the conveying table 2 is formed of glass into a circular shape, and the conveying table 2 has a slight warpage in the vicinity of the outer edge due to the work accuracy during the molding process. If the conveying table 2 with this kind of tilting rotates with a slight gap on the underside of the entire row of guides 7, as Figure 16 As shown by the dotted line, the size of the gap γ between the lower surface 7z of the alignment guide 7 and the upper surface 2s of the transport table 2 changes. If the size of the gap γ changes, especially when the gap γ is small, from the gap γ between the lower surface 7z of the alignment guide 7 and the upper surface 2s of the conveying table 2 to the upper surface 2s of the conveying table 2 Work W 2 Jet air from the gap, the air hits the workpiece W 2. Here, the workpiece W 2 By positively charging the lower surface of the transport table 2 as described above, the positive charge generated on the lower surface of the transport table 2 is attracted to the upper surface 2s of the transport table 2.

[0100] However, if the air ejected from the above gap γ hits the workpiece W 2 , At this time, since the workpiece W 2 Applied pressure, workpiece W 2 It may be far away from the guide surface 7a or the workpiece W 2 The posture becomes unstable.

[0101] In order to prevent this, the alignment guide 7 is provided with vacuuming units 17 and 18 that vacuum the gap γ formed between the lower surface 7z of the alignment guide 7 and the upper surface 2s of the transport table 2. That is, the vacuuming units 17 and 18 have a vacuum source 17 and a suction passage 18 provided in the alignment guide 7. One end 18a of the suction passage 18 is open to the gap γ, and the other end 18b is connected to the vacuum source 17 via a connection line 17a. connection.

[0102] in Figure 16 Here, through the vacuum source 17 and the suction passage 18, the gap γ between the lower surface 7z of the alignment guide 7 and the upper surface 2s of the conveying table 2 is always evacuated in the directions of the arrows δ1, δ2, and δ3. By this evacuation, even if the size of the gap γ changes during the rotation of the transport table 2, air will not flow from the gap to the workpiece W 2 Spray and hit the workpiece W 2. Therefore, the workpiece W 2 It is conveyed in a state of being stably electrostatically attracted to the upper surface 2s of the conveying table 2.

[0103] Here, as relative to Figure 16 Comparison chart in Figure 17 The case where the alignment guide 70 without the vacuuming units 17 and 18 and the conveying table 2 are provided with a small gap is shown. Such as Figure 17 As shown by the dotted line, if the size of the gap γ between the lower surface 70z of the alignment guide 70 and the upper surface 2s of the conveying table 2 changes, especially when the size of the gap γ becomes small, the air existing in the gap is compressed, so The air flows from the gap to the direction of the arrow ε toward the workpiece W placed on the upper surface 2s of the rotating conveyor 2 2 Spray and hit the workpiece W 2. Due to the air pressure, the workpiece W 2 Away from the guide surface 70a, so even if the conveying table 2 rotates and the workpiece W 2 Arrivals image 3 Confluence point in 7x, workpiece W 2 Can't be image 3 The illustrated workpiece conveying arc 5 is placed in a row, and the high-precision workpiece positioning that is the object of the present invention cannot be performed. In addition, even if the air does not make the workpiece W 2 When the distance from the guide surface 70a is so large, the workpiece W 2 The posture becomes unstable near the guide surface 70a, etc., and high-precision workpiece positioning, which is the object of the present invention, cannot be achieved.

[0104] In contrast, according to the present invention, since the gap γ between the lower surface 7z of the alignment guide 7 and the upper surface 2s of the conveying table 2 is always evacuated, air will not be ejected from the gap γ and hit the workpiece W. 2 , It is possible to stably make the workpiece W on the conveying table 2 2 Entire column.

[0105] If the artifact is image 3 When the workpiece is transported in a state of being placed in a line on the workpiece transport arc 5, then the workpiece W arrives at the imaging unit 20, and the side camera portion 8, the inner surface camera portion 9, and the upper surface camera portion 10 of the imaging unit 20 The lower surface camera section 11, the front surface camera section 12, and the rear surface camera section 13 are figure 2 Each surface is photographed in the direction indicated by the middle arrow A to F to perform visual inspection. In this case, due to the action of the suction and guide surface 7 formed by the electric charge present on the lower surface of the transport table 2, the workpiece W is positioned with high precision, and therefore the imaging accuracy of the imaging unit 20 is improved. The work W on which the appearance inspection has been completed reaches the discharge unit 14 and is discharged to a storage box (not shown) based on the result of the appearance inspection.

[0106] When the workpiece W is discharged by the discharging unit 14, for example, the figure 2 Compressed air is ejected from the side B in front of the paper surface in the middle, so that the workpiece W flies to the outer peripheral side of the conveying table 2 and is guided to the storage box. The workpiece W in the storage box has a positive charge on the conveying table 2 due to the Image 6 (B), Figure 7 The state shown in (b), but returned by moving away from the positive charge Image 6 (A), Figure 7 (A) State. In the meantime, the work W itself does not generate electrification due to static electricity.

[0107] As described above, although static electricity is used to attract the workpiece W to the transport table 2 in this embodiment, the Figure 8 (A) and (b) illustrate that the workpiece W will not be electrostatically damaged or deteriorated due to static electricity.

[0108] Figure 8 (A) shows the state of the electric force lines generated by the positive charge existing on the lower surface of the conveying table 2 when the workpiece W has been placed on the upper surface of the conveying table 2 and the lower surface of the conveying table 2 is positively charged. Such as Figure 8 As shown in (a), the line of power is emitted from a positive charge and terminates at a negative charge. In this case, it can be considered that the negative charge exists at infinity, and therefore the line of force E1 is emitted from the positive charge existing on the lower surface of the transport table 2 and penetrates the transport table 2 and the workpiece W toward the upper side. In addition, there are lines of electric force that are emitted from this positive charge and directed downward or left and right. However, they are not shown in the drawings because they are not related to the present invention. At this time, the electrodes Wa and Wb of the workpiece W are electrostatically induced, and the main body Wd is polarized by the dielectric, so that negative charges appear on the respective lower surfaces, and positive charges appear on the respective upper surfaces. At this time, since the electrodes Wa and Wb are electrical conductors, positive charges are concentrated on the upper surface and negative charges are concentrated on the lower surface. Therefore, lines of electric force E2 are generated inside the electrodes Wa and Wb due to these charges. The direction of the line of force is emitted from the positive charge present on the upper surface and ends at the negative charge present on the lower surface.

[0109] Therefore, the lines of electric force E1 and E2 in the electrodes Wa and Wb are opposite to each other, so they cancel out, as Figure 8 As shown in (b), it becomes a state where there are no lines of electric force in the electrodes Wa and Wb. Like this Figure 8 In (b), E1' is used to indicate the power lines that are disconnected in the electrodes Wa and Wb. In this state, there are no lines of electric force in the electrodes Wa and Wb, so the electrodes Wa and Wb have the same potential. That is, no voltage is applied between the electrode Wa and the electrode Wb, and electrostatic breakdown of the workpiece or deterioration of characteristics does not occur.

[0110] However, the following situation should also be considered: in the transitional state where the workpiece W is transferred from the vibration-free part 4 to the transport table 2, the electric charges in the electrodes Wa and Wb of the workpiece W are based on the existence of the lower surface of the transport table 2 The electrostatic induction caused by the electric charge moves in each electrode, and the electrodes Wa and Wb repeatedly contact or move away from the vibration-free part 4 and the transport table 2. It should also be considered that if the electric charges in the electrodes Wa and Wb move between the electrodes Wa and Wb and the outside when such electrodes Wa and Wb are in contact with or away from each other, electrostatic breakdown due to discharge will occur. In this case, the non-vibration part 4 is composed of a material having a high resistance value, such as an insulator, similarly to the transport table 2, and therefore, there is no charge movement between the electrodes Wa and Wb.

[0111] In addition, in the above-mentioned embodiment, the example in which the lower surface of the conveyance table 2 is positively charged is shown, but it may be negatively charged as needed. In addition, although an example is shown in which the transport table 2 is made of a material made of glass, the material of the transport table 2 is not limited to glass as long as it is a transparent body.

[0112] Second embodiment

[0113] Next, use Figure 10 to Figure 15 The second embodiment of the present invention will be described.

[0114] Figure 10 to Figure 15 The second embodiment of the present invention shown is different only in that a conductive plate (conductor) 15 is arranged below the conveying table 2 instead of disposing the charging unit 6A below the conveying table 2. The other structure is different from Figure 1 to Figure 9 The first embodiment shown is substantially the same.

[0115] in Figure 10 to Figure 15 In the second embodiment shown, the Figure 1 to Figure 9 The same parts in the first embodiment shown are denoted by the same symbols, and detailed descriptions are omitted.

[0116] here, Picture 10 Is viewed from the direction of arrow Y figure 1 A perspective view of the area S enclosed by the dashed line in Figure 4 Corresponding. in Picture 10 On the lower side of the middle conveying table 2, a conductive plate 15 made of a conductor and the lower surface of the conveying table 2 are arranged at a slight interval instead of Figure 4 In the charging unit 6A composed of an ionizer 6. The conductive plate 15 has a flat shape, such as Picture 12 As shown, its surface 15a is substantially parallel to the conveying table 2. In addition, a DC power supply 16 is connected to the conductive plate 15 to apply a DC voltage to constitute an electric field generating unit. by Picture 11 Shows the location of the conductive plate 15. Picture 11 Means by figure 1 An enlarged top view of the area S enclosed by the dashed line, with image 3 Corresponding. in Picture 11 Among them, the conductive plate 15 extends in a slender shape in the horizontal direction, and is arranged to transport the arc 5 from the transfer point 4x to the workpiece on the transport table 2 of the workpiece W and the guide surface 7a with the alignment guide 7 The lower side of the corresponding conveying table 2 is conveyed along the workpiece W of the workpiece W in the longer direction.

[0117] Secondly, use Figure 10 to Figure 15 The effect of the second embodiment of the present invention will be explained.

[0118] in Picture 11 In this case, the workpieces W transported in a row by the vibration of the linear feeder 1 are transferred to the transfer point 4x on the transport table 2 and are affected by the electric charge generated on the conductive plate 15 connected to the DC power supply 16. The resulting electrostatic induction and dielectric polarization are attracted to the upper surface of the transport table 2.

[0119] in Picture 12 The state of the adsorption is shown in. in Picture 12 Here, the conductive plate 15 and the lower surface of the transport table 2 are arranged with a small gap therebetween, and a DC power source 16 is connected to the conductive plate 15 to apply a positive DC voltage. Therefore, positive charges appear on the conductive plate 15.

[0120] Because of the positive charge Figure 5 Similarly, dielectric polarization is induced, and negative charges appear on the lower surface side inside the transport table 2 opposed to the conductive plate 15 and positive charges appear on the upper surface side. In the same way, the workpiece W at the transfer point 4x transferred from the vibration-free part 4 to the transfer table 2 2 In the electrodes Wa and Wb due to electrostatic induction, and the main body Wb due to dielectric polarization, negative charges appear on the lower surface side, and positive charges appear on the upper surface side.

[0121] Moreover, the electrostatic attraction force G shown by the arrow acts between the negative charges appearing on the lower surface side of the electrodes Wa, Wb and the main body Wd and the positive charges of the conductive plate 15, because the workpiece W 2 It is transported in the direction of arrow X by the rotation of the transport table 2 in a state of being sucked on the upper surface of the transport table 2.

[0122] In this case, and Figure 8 Similarly to the first embodiments shown in (a) and (b), the work W itself does not generate electrification due to static electricity, and therefore no electrostatic damage or characteristic degradation occurs when attacking W.

[0123] In addition, in the description of the above-mentioned embodiment, it was described that the surface of the conductive plate 15 and the surface of the conveying table 2 are substantially parallel, but the positional relationship between the surface of the conductive plate 15 and the surface of the conveying table 2 is not limited to this. Figure 13 show Picture 11 The zoomed view in the L direction, Figure 13 The condition of the electric power lines emitted from the positive charge of the conductive plate 15 is shown in FIG.

[0124] Such as Figure 13 As shown, since the power line penetrates the conveying table 2 and the workpiece W, electrostatic induction and dielectric polarization are generated, a negative charge is generated on the lower surface of the workpiece W, and a positive charge is generated on the upper surface of the workpiece W. Here, for the sake of simplicity, the charge generated in the transport table 2 due to dielectric polarization is not shown.

[0125] Such as Figure 13 As shown, among the lines of force emitted from the positive charge on the conductive plate 15, the lines of force from the positive charge existing near the end surface 15x of the conductive plate 15 (Ex in the figure) have a direction to the side where no charge exists, that is, the conductive plate The outer side of 15 is curved. Therefore, it can also be as Figure 14 In that way, the conductive plate 15 is arranged such that its surface 15a is substantially at right angles to the conveying table 2, instead of Figure 13 The structure shown. In this case, the conductive plate 15 extends in a slender shape in the horizontal direction, and is arranged on the lower side of the conveying table 2 corresponding to the guide surface 7a of the alignment guide body 7, and the longitudinal direction corresponds to the workpiece W. The workpiece conveying arc 5 is substantially parallel.

[0126] in Figure 14 Among the lines of force generated from the positive charges of the conductive plate 15, the lines of force generated from the positive charges near the end surface 15x penetrate the transport table 2 and the work W. Therefore, with Figure 13 Similarly, in the case shown, a negative charge is generated on the lower surface of the workpiece W and a positive charge is generated on the upper surface of the workpiece W through electrostatic induction and dielectric polarization.

[0127] Again, such as Figure 15 As shown, a conductive plate 15 having an L-shaped cross section is also provided. In this case, the surface 15b of the two intersecting surfaces 15b and 15c of the conductive plate 15 may be arranged substantially at right angles to the transport table 2 and the surface 15c may be arranged substantially parallel to the transport table 2. In this case, the conductor 15 extends in a slender shape in the horizontal direction, and is arranged on the lower side of the conveying table 2 corresponding to the guide surface 7a of the alignment guide 7, and the longer direction is the same as the workpiece W. The workpiece conveying arc 5 is substantially parallel.

[0128] in Figure 15 In this case, the power lines do not intersect each other. Therefore, among the power lines emitted from the positive charges of the conductive plate 15, the power lines emitted from the positive charges existing in the vicinity of the end face 15x penetrate the transport table 2 and the workpiece W. Therefore, with Figure 13 Similarly, a negative charge is generated on the lower surface of the workpiece W and a positive charge is generated on the upper surface of the workpiece W through electrostatic induction and dielectric polarization.

[0129] In addition, in the description of the second embodiment described above, an example in which the conductive plate 15 is positively charged is shown, but it may be negatively charged as necessary.