JP2010014425A - Foreign matter detection method and foreign matter detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foreign matter detection method capable of uniforming pressure on a surface of a liquid crystal display panel. <P>SOLUTION: This foreign matter detection method is for detecting whether foreign matters have mixed in between a pair of flexible substrates of a liquid crystal display panel, with liquid crystal interposed in between the substrates. Display defects caused by foreign matter having got mixed in between the substrates are made visible, by moving an air blow-out bar in parallel to the surface of the display panel, the air blow-out bar having a plurality of air blow-out ports disposed lengthwise in the blow-out bar, from which air is blown out to press the surface of the display panel by air pressure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a foreign matter detection method and a foreign matter detection device for detecting the presence or absence of foreign matter mixed between substrates of a liquid crystal display panel.

  In recent years, liquid crystal display panels have been widely used as display units for home appliances such as computers and televisions. In general, a liquid crystal display panel has a configuration in which a pair of substrates, which are a thin film transistor (TFT) array substrate and a color filter (CF) substrate, are arranged in parallel to each other at a predetermined interval, and liquid crystal is filled between the substrates. There is no. A plurality of pixel electrodes are formed in a matrix on the TFT array substrate, and a common electrode is formed on almost the entire surface of the CF substrate, and the orientation of the liquid crystal can be controlled by changing the voltage applied between these electrodes. Can be done.

  Such a liquid crystal display panel is manufactured by manufacturing a TFT array substrate and a CF substrate, and then bonding the substrates together and sealing the liquid crystal between the substrates. Usually, the manufactured liquid crystal display panel is subjected to quality inspection such as lighting inspection.

  In the lighting inspection, light is irradiated from the back surface of the liquid crystal display panel, and a signal voltage for inspection is applied to each of the pixel electrode of the TFT array substrate and the common electrode of the CF substrate so that all pixels are turned on. The inspection image is made visible on the display screen of the display panel, and the operator inspects the presence or absence of defective pixels by visual observation or the like.

  In this case, when conductive foreign matter is mixed between the source electrode, gate electrode, pixel electrode formed on the TFT array substrate, and the common electrode formed on the CF substrate, the two electrodes are short-circuited. Therefore, it is detected as a dot-like or line-like display defect.

  In such lighting inspection, if the size of the conductive foreign material exceeds the distance between each electrode of the TFT array substrate and the common electrode of the CF substrate, a defective portion where both electrodes are short-circuited by the conductive foreign material is detected. However, if the size of the conductive foreign material is about the distance between each electrode of the TFT array substrate and the common electrode of the CF substrate, the short circuit between the two electrodes due to the conductive foreign material may be unstable and may not always occur. In some cases, it is not possible to detect such a line-like or dot-like display defect where a conductive foreign substance is mixed.

  A liquid crystal display panel having an unstable short circuit between both electrodes due to conductive foreign matter not detected by such lighting inspection may cause display defects in the market.

  In order to improve this, as described in Patent Document 1 below, the surface of the liquid crystal display panel is pressed with a rubber roller jig 50 as shown in FIG. The display defect has been made obvious by changing the short circuit state from the uneasy state to the shorted state.

  The rubber roller jig 50 includes a cylindrical roller 51 made of butyl rubber or the like, and a grip portion 52 to which the roller 51 is rotatably attached. In the lighting inspection, the surface of the liquid crystal display panel around the roller 51 is observed obliquely from above while rolling the roller 51 on the surface of the liquid crystal display panel.

  FIG. 7 is a diagram showing a cross-sectional structure of the liquid crystal display panel 30 in which conductive foreign matter is mixed. As shown in the figure, the TFT array substrate 31 has a configuration in which pixel electrodes 33 are formed in a matrix on the upper surface of a flexible glass substrate 32. The CF substrate 36 has a configuration in which a common electrode 38 is formed on the lower surface of a flexible glass substrate 37. A liquid crystal 34 is sealed between the electrodes 33 and 38.

  The TFT array substrate 31 is formed so that a plurality of source electrodes 42 intersect with a plurality of gate electrodes 41, and is surrounded by adjacent gate electrodes 41 and 41 and adjacent source electrodes 42 and 42. The pixel electrode 33 described above is formed in each region. Further, a thin film transistor (TFT) 43 is formed in the vicinity of the intersection between the gate electrode 41 and the source electrode 42.

  The TFT 43 is turned on / off by a gate signal voltage applied to the gate electrode 41, and the source signal voltage from the source electrode 42 is applied to the pixel electrode 33 via the semiconductor layer 44 and the drain electrode 45. .

  In addition, a lattice-shaped black matrix 46 is formed on the CF substrate 36 so as to shield the gate electrode 41 and the source electrode 42 described above, and the region surrounded by the adjacent black matrices 46, 46 is red. Colored layers 47 of blue, green, etc. are formed.

  As shown in FIG. 7, the conductive foreign material 48 is mixed on the pixel electrode 43 for some reason. In this case, the size of the conductive foreign material 48 is about the size of the interval between the pixel electrode 33 and the common electrode 38.

  As shown in the figure, in this state, there is no short circuit between the electrodes 33 and 38 due to the conductive foreign matter 48. However, if the tip of the conductive foreign matter 48 comes into contact with the common electrode 38 for some reason, the both electrodes 33 and 38 are shown. It is in an unstable state in which a short circuit occurs.

  The surface of the liquid crystal display panel 30 is formed with the rubber roller jig 50 described above in order to change the state where the electrodes 33 and 38 are short-circuited from the state where the short-circuit between the electrodes 33 and 38 due to the conductive foreign material 48 is anxious. By narrowing the gap between the electrodes 33 and 38, the tip of the conductive foreign material 48 is brought into contact with the common electrode 38, and a display defect due to a short circuit between the electrodes 33 and 38 can be caused.

JP-A 63-293581

  However, since the operator presses the surface of the liquid crystal display panel 30 using the rubber roller jig 50, variations in the pressing position, variations in the pressing force, variations in pressing timing, and the like occur.

  Therefore, for example, in the foreign object detection using the rubber roller jig 50 for the same liquid crystal display panel, even if a display defect does not occur when pressed by one worker, a display defect occurs when pressed by another worker, etc. The accuracy of foreign object detection was lacking due to variations due to differences in workers.

  Accordingly, the problem to be solved by the present invention is to provide a foreign matter detection method and a foreign matter detection device capable of making the pressure on the surface of the liquid crystal display panel constant.

  In order to solve the above problems, the present invention is a foreign matter detection method for detecting the presence or absence of foreign matter mixed between substrates of a liquid crystal display panel in which liquid crystal is interposed between a pair of flexible substrates, the liquid crystal display The substrate is obtained by moving, in parallel with the surface of the liquid crystal display panel, an air ejection bar in which a plurality of air ejection ports for ejecting air for pressing the surface of the panel by air pressure are arranged in the longitudinal direction. The gist is to make display defects due to foreign matters mixed in between.

  In order to solve the above-mentioned problem, the present invention is a foreign matter detection device for detecting the presence or absence of foreign matter mixed between liquid crystal display panels in which liquid crystal is interposed between a pair of flexible substrates, An air ejection bar in which a plurality of air ejection ports for ejecting air for pressing the surface of the liquid crystal display panel by air pressure are arranged in the longitudinal direction, and the air ejection bars are parallel to the surface of the liquid crystal display panel. The gist of the invention is that it includes a bar moving means for moving.

  According to the foreign object detection method and the foreign object detection device having such a configuration, the air ejection bar in which a plurality of air ejection ports for ejecting air for pressing the surface of the liquid crystal display panel by air pressure are arranged in the longitudinal direction. By moving parallel to the surface of the liquid crystal display panel, display defects due to foreign matters mixed between the substrates are made obvious, so there is no variation in pressing position, variation in pressing force, variation in pressing timing, etc. As a result, the pressure on the surface of the liquid crystal display panel can be made constant with good reproducibility, and accurate foreign matter detection can be performed.

  In this case, the surface of the liquid crystal display panel can be uniformly pressed by adopting a configuration in which the ejection of air from the air ejection port is intermittent.

  In addition, if the air ejection direction from the air ejection port is inclined at a predetermined angle with respect to the surface of the liquid crystal display panel, display defects generated on the surface of the liquid crystal display panel are hidden by the air ejection bar. Therefore, the visibility of display defects is improved. Further, if the back surface of the liquid crystal display panel whose surface is pressed by the air ejected from the air ejection bar is supported by a support roller, the liquid crystal display panel can be prevented from being damaged due to excessive bending to the back surface side. Since the gap between the substrates can be narrowed, the display defect due to the foreign matter in the liquid crystal display panel can be easily revealed.

  Also, if the surface of the support roller is white, it is alleviated that display defects generated on the surface of the liquid crystal display panel are obstructed by the shadow of the support roller, so that a decrease in the visibility of display defects is suppressed. Has been. Further, when the air ejection bar is inclined at a predetermined angle with respect to one side of the liquid crystal display panel, the visibility of vertical or horizontal linear display defects generated on the surface of the liquid crystal display panel is improved. .

  According to the foreign matter detection method and the foreign matter detection device according to the present invention, the surface of the liquid crystal display panel is pressed by the air pressure of the air jetted from the air jetting bar. Therefore, accurate foreign object detection can be performed.

  Hereinafter, embodiments of a foreign object detection method and a foreign object detection device according to the present invention will be described in detail with reference to the drawings. In the following description, the same components as those constituting the liquid crystal display panel 30 described with reference to FIG.

  FIG. 1 is a top view showing a schematic configuration of a foreign object detection device according to an embodiment of the present invention, and FIG. 2 is a side view of the foreign object detection device of FIG.

  As shown in FIGS. 1 and 2, the foreign object detection device 1 has the liquid crystal display panel 30 having an opening 2 a that is opened in a rectangular shape so that the image display region 30 a of the liquid crystal display panel 30 is exposed. A stage 2 is provided.

  An air ejection bar 3 that presses the surface of the liquid crystal display panel 30 placed on the stage 2 with air pressure is provided on the upper side of the stage 2 so as to straddle between the upper side and the lower side of the stage 2.

  In the air ejection bar 3, a plurality of nozzles 5, 5, 5,..., In which air ejection ports 6a, 6b from which air is ejected are formed are arranged along the longitudinal direction. As shown in FIG. 2, the nozzle 5 is located below the main body portion 4 of the air ejection bar 3 so that the air ejection direction from the air ejection ports 6 a and 6 b is inclined by a predetermined angle with respect to the surface of the liquid crystal display panel 30. It is attached with an inclination.

  Two compressed air passages 7 and 8 as shown in the figure are formed inside the main body portion 4 of the air ejection bar 3, and are connected to the air ejection ports 6a and 6b of the nozzles 5 arranged alternately. Has been. Specifically, the compressed air passage 7 is connected to the air outlet 6 a of the nozzle 5, and the compressed air passage 8 is connected to the air outlet 6 b of the adjacent nozzle 5.

  A pneumatic circuit 9 as shown is connected to the compressed air passages 7 and 8. The pneumatic circuit 9 includes a switching valve 10 that can switch the destination of compressed air in two directions, a pneumatic valve 11 that is connected to the switching valve 10, and a pneumatic pump 12 that is connected to the pneumatic valve 11. . Operations of the switching valve 10 and the pneumatic valve 11 are controlled by the control unit 13.

  Note that a compressed air regulator (not shown) is provided between the compressed air valve 11 and the compressed air pump 12, and the pressure of the compressed air to be supplied is kept constant so as to become a predetermined pressure.

  In addition, one compressed air delivery destination of the switching valve 10 is connected to the compressed air passage 7, and the other compressed air delivery destination is connected to the compressed air passage 8. Accordingly, air is alternately ejected from the air ejection ports 6a and 6b by the switching operation of the compressed air delivery destination of the switching valve 10. The switching operation of the switching valve 10 is controlled by the control unit 13.

  FIG. 1 shows a state in which the destination of compressed air is switched to the compressed air passage 7 by the switching valve 10 and air is ejected from the air outlet 6a. FIG. 3 shows the state of FIG. After the air ejection bar 3 has moved to the right by a predetermined distance, the destination of compressed air is switched to the compressed air passage 8 by the switching valve 10, and the air is ejected from the air ejection port 6b.

  In addition to the switching operation of the switching valve 10, the opening / closing operation of the compressed air valve 11 is intermittently controlled by the control unit 13. FIG. 4 is a diagram showing a portion 27 on the surface of the liquid crystal display panel 30 that is pressed by air intermittently ejected from the air ejection ports 6a and 6b. As shown in the drawing, the portion 27 on the surface of the liquid crystal display panel 30 that is pressed by the air alternately ejected from the air outlets 6 a and 6 b is uniform with respect to the image display area 30 a of the liquid crystal display panel 30. Is arranged.

  The nozzle 5 provided in the air ejection bar 3 is formed of a transparent resin. Thus, by forming the nozzle 5 from a transparent resin, it is possible to prevent the display defect generated on the surface of the liquid crystal display panel 30 from being hidden by the nozzle 5, and the visibility of the display defect is improved.

  Connecting portions 15, 15 project from both ends of the body portion 4 of the air ejection bar 3. The connecting portions 15 and 15 are supported by support brackets 16 and 16, respectively. In addition, it is good to make it the structure which attaches the connection parts 15 and 15 to the support brackets 16 and 16 so that the angle of the air ejected from the nozzle 5 of the air ejection bar 3 can be adjusted.

  Support brackets 16, 16 that support both ends of the air ejection bar 3 are fixedly attached to the upper surfaces of base portions 17, 17 provided on the upper side and the lower side of the stage 2, respectively. The base portions 17 and 17 are movable to the left and right along the upper and lower sides of the stage 2 by slide rails 18 and 18 provided so as to extend along the upper and lower sides of the stage 2, respectively. .

  The base portions 17 and 17 include motors 19 and 19. When the motors 19 and 19 are driven by the control unit 13, the base portions 17 and 17 are moved in the horizontal direction along the slide rails 18 and 18. Has been moved to. Therefore, the air ejection bar 3 is moved in parallel with the surface of the liquid crystal display panel 30 by the base portions 17 and 17.

  Further, below the stage 2, a support roller 20 having a white surface that contacts and supports the back surface of the liquid crystal display panel 30 placed on the stage 2 is provided. The support roller 20 is provided so as to straddle the opening 2 a of the stage 2 between the upper side and the lower side of the stage 2.

  In this case, since the surface of the support roller 20 is white, it is alleviated that display defects generated on the surface of the liquid crystal display panel 30 are blocked by the shadow of the support roller 20 due to light emitted from the backlight 24 described later. Thus, a reduction in the visibility of display defects is suppressed.

  Support shafts 21 and 21 protrude from both ends of the support roller 20, respectively. The support shafts 21 and 21 are rotatably supported by support brackets 22 and 22, respectively.

  The support brackets 22 and 22 are attached and fixed to the lower surfaces of the base portions 17 and 17, and are moved to the left and right as the base portions 17 and 17 are moved. Therefore, the support roller 20 is rolled while being in contact with the back surface of the liquid crystal display panel 30. In this case, as shown in the figure, the support roller 20 is provided so as to support the back surface corresponding to the surface of the liquid crystal display panel 30 pressed by the air ejected from the air ejection bar 3.

  As shown in FIG. 2, the foreign object detection device 1 includes a backlight 24 that irradiates light from below toward the liquid crystal display panel 30 placed on the stage 2. Further, a frame 26 having a signal input pin 25 for inputting an inspection signal to a signal input portion formed at an end portion of the liquid crystal display panel 30 placed on the stage 2 is provided.

  Next, an operation procedure of the foreign object detection apparatus 1 having such a configuration will be described with reference to FIGS. First, the liquid crystal display panel 30 is placed on the stage 2 of the foreign object detection device 1 as shown in FIG. At this time, the image display area 30 a on the surface of the liquid crystal display panel 30 is placed so as to be positioned in the opening 2 a of the stage 2.

  Next, the frame 26 is lowered to bring the signal input pin 25 into contact with the signal input portion of the liquid crystal display panel 30. As a result, a circuit that generates an inspection signal (not shown) and the signal input unit of the liquid crystal display panel 30 are electrically connected via the signal input pin 25.

  Then, as shown in FIG. 2, all the pixels in the image display area 30 a of the liquid crystal display panel 30 are input by inputting an inspection signal to the signal input unit of the liquid crystal display panel 30 with the backlight 24 turned on. Visible.

  Next, when the motors 19 are driven by the control unit 13, the air ejection bar 3 whose both ends are fixed to the base units 17, 17 is moved rightward.

  When the compressed air valve 11 is opened by the control unit 13 and the compressed air delivery destination by the switching valve 10 is switched to the compressed air passage 7, the air injection of the nozzle 5 of the air ejection bar 3 as shown in FIG. Air is ejected from the outlet 6a. The surface of the liquid crystal display panel 30 is pressed by the air pressure of the ejected air. At this time, the liquid crystal display panel 30 is sandwiched between the air pressure generated by the air ejected from the air ejection port 6a and the upper surface of the support roller 20, and the gap between the substrates 31 and 36 is narrowed.

  In this case, since the nozzle 5 is formed of a transparent resin, the display defect generated in the image display region 30a of the liquid crystal display panel 30 when pressed by the blown air is prevented from being hidden by the nozzle 5. The visibility of display defects is improved.

  In addition, as shown in FIG. 2, the direction in which the air is ejected from the nozzle 5 is inclined by a predetermined angle with respect to the surface of the liquid crystal display panel 30, so that the pressed region is less likely to be a shadow of the nozzle 5. ing.

  Next, when the compressed air valve 11 is closed by the control unit 13, the ejection of air from the air ejection port 6 a of the nozzle 5 of the air ejection bar 3 is stopped.

  Next, after the air ejection bar 3 has moved to the right by a predetermined distance from the state shown in FIG. 1, the control unit 13 opens the compressed air valve 11 again, and the destination of compressed air from the switching valve 10 is the compressed air passage. When switched to 8, air is ejected from the air ejection port 6b as shown in FIG. 3, and the surface of the liquid crystal display panel 30 is pressed.

  Also at this time, the liquid crystal display panel 30 is sandwiched between the air pressure generated by the air ejected from the air ejection port 6b and the upper surface of the support roller 20, and the gap between the substrates 31 and 36 is narrowed. .

  When the air ejection bar 3 is moved from the left end portion to the right end portion of the liquid crystal display panel 30 while intermittently repeating the opening / closing operation of the pneumatic valve 11 together with the switching operation of the switching valve 10 as shown in FIG. As shown in FIG. 4, the portion 27 intermittently ejected from the air ejection ports 6a and 6b and pressed by the air is uniformly arranged over the entire image display region 30a of the liquid crystal display panel 30.

  Then, the inspection image of the liquid crystal display panel 30 when pressed by the air ejected from the air ejection bar 3 and after being pressed is observed to confirm the presence or absence of a display defect. Specifically, as indicated by an arrow 18 in FIG. 2, the surface of the liquid crystal display panel 30 around the nozzle 5 of the air ejection bar 3 is observed obliquely from above.

  At this time, as shown in FIG. 7, the conductive foreign matter 48 mixed in the liquid crystal 34 is detected as a dot-like display defect when, for example, the pixel electrode 33 and the common electrode 38 are short-circuited.

  Further, when the conductive foreign material 48 short-circuits the gate electrode 41 and the common electrode 38, it is detected as a linear display defect extending in the horizontal direction. Further, when the conductive foreign material 48 short-circuits the source electrode 42 and the common electrode 38, it is detected as a linear display defect extending in the vertical direction.

  The inspection image displayed on the liquid crystal display panel 30 that has been made visible in this manner is observed by the operator's eyes, and dot-like display defects or line-like defects caused by the conductive foreign matter 48 are included in the inspection image. If there is a display defect, it is considered a defective product.

  In such a foreign matter detection device 1, the air ejection bar 3 in which a plurality of air ejection ports 6a and 6b for ejecting air for pressing the surface of the liquid crystal display panel 30 by air pressure is disposed in the longitudinal direction is moved as a bar. By moving the means (base portion 17, slide rail 18, motor 19, etc.) parallel to the surface of the liquid crystal display panel 30, display defects due to foreign matters mixed between the substrates 31 and 36 can be made obvious. It has become.

  Therefore, as compared with the case where the operator presses the surface of the liquid crystal display panel 30 using the rubber roller jig 50 shown in FIG. 6, the pressing position, the pressing force, and the pressing timing are different. The pressure on the surface of the liquid crystal display panel 30 can be made constant with good reproducibility, and accurate foreign object detection can be performed.

  In this case, as described above, the surface of the liquid crystal display panel 30 can be uniformly pressed by intermittently ejecting air from the plurality of air ejection ports 6a and 6b provided in the air ejection bar 3.

  Further, since the direction of air ejection from the air ejection ports 6a and 6b is inclined by a predetermined angle with respect to the surface of the liquid crystal display panel 30, display defects generated on the surface of the liquid crystal display panel 30 are caused by the air ejection bars 3 and nozzles. 5 is prevented from being hidden, and the visibility of display defects is improved.

  Furthermore, since the back surface of the liquid crystal display panel 30 whose surface is pressed by the air ejected from the air ejection bar 3 is supported by the support roller 20, damage due to excessive deflection of the liquid crystal display panel 30 toward the back surface side is prevented. In addition, the gap between the substrates 31 and 36 can be narrowed, and display defects due to foreign matter on the liquid crystal display panel 30 can be easily realized.

  Further, since the surface of the support roller 20 is white, it is alleviated that display defects generated on the surface of the liquid crystal display panel 30 are obstructed by the shadow of the support roller 20, and a reduction in the visibility of display defects is suppressed. Yes.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to such Embodiment at all, Of course, in the range which does not deviate from the summary of this invention, it can implement in a various aspect. For example, as shown in the modification of FIG. 5, the air ejection bar 3 provided in the foreign object detection device 1 may be configured to be inclined at a predetermined angle with respect to one side of the liquid crystal display panel 30.

  In this way, the vertical line shape generated on the surface of the liquid crystal display panel 30 as shown in the drawing is larger than the case where the air ejection bar 3 is provided in parallel to one side of the liquid crystal display panel 30 as described above. The visibility of the display defect 29 is improved.

  Moreover, although the foreign material detection apparatus 1 provided with the one air ejection bar 3 and the one support roller 20 was demonstrated, it is not limited to these numbers, and more air ejection bars 3 and the support roller 20 are provided. A configuration may be used.

It is the top view which showed schematic structure of the foreign material detection apparatus of the liquid crystal display panel which concerns on one Embodiment of this invention. It is the side view which looked at the foreign material detection apparatus of FIG. 1 from the side. It is the figure which showed the state which ejected air, the air ejection bar with which the foreign material detection apparatus of FIG. 1 is provided moving rightward. It is the figure which showed the site | part of the liquid crystal display panel pressed by the foreign material detection apparatus of FIG. It is the figure which showed the modification of the foreign material detection apparatus of FIG. It is the external appearance perspective view which showed schematic structure of the rubber roller jig which presses the surface of the liquid crystal display panel used conventionally. It is sectional drawing which showed the state in which the conductive foreign material was mixed between the board | substrates of a liquid crystal display panel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Foreign object detection apparatus 2 Stage 3 Air ejection bar 5 Nozzle 6a, 6b Air ejection port 7, 8 Pneumatic air passage 9 Pneumatic circuit 10 Switch valve 11 Pneumatic valve 12 Pneumatic pump 13 Control part 17 Base part 18 Slide rail 19 Motor 20 Support roller 24 Backlight 25 Signal input pin 26 Frame 27 Pressed portion 29 Display defect 30 Liquid crystal display panel 30a Image display area 31 TFT array substrate 34 Liquid crystal 36 CF substrate 48 Conductive foreign matter

Claims (12)

  A foreign matter detection method for detecting the presence or absence of foreign matter mixed between liquid crystal display panels in which liquid crystal is interposed between a pair of flexible substrates, wherein the surface of the liquid crystal display panel is pressed by air pressure. Display defects due to foreign matter mixed in between the substrates are manifested by moving an air ejection bar, in which a plurality of air ejection ports, from which the air is ejected, are arranged in the longitudinal direction, in parallel with the surface of the liquid crystal display panel A foreign matter detection method characterized by comprising:   The foreign object detection method according to claim 1, wherein the ejection of air from the air ejection port is intermittent.   The foreign matter detection method according to claim 1 or 2, wherein a jet direction of air from the air jet port is inclined at a predetermined angle with respect to a surface of the liquid crystal display panel.   The foreign object detection method according to claim 1, wherein a back surface of the liquid crystal display panel whose surface is pressed by air ejected from the air ejection bar is supported by a support roller.   The foreign object detection method according to claim 4, wherein a surface of the support roller is white.   6. The foreign matter detection method according to claim 1, wherein the air ejection bar is inclined at a predetermined angle with respect to one side of the liquid crystal display panel.   A foreign matter detection device for detecting the presence or absence of foreign matter mixed between liquid crystal display panels having liquid crystal interposed between a pair of flexible substrates, and for pressing the surface of the liquid crystal display panel with air pressure And a bar moving means for moving the air ejection bar in parallel to the surface of the liquid crystal display panel. Foreign matter detection device.   The foreign object detection device according to claim 7, wherein a direction in which air is ejected from the air ejection port is inclined at a predetermined angle with respect to a surface of the liquid crystal display panel.   The foreign object detection device according to claim 7 or 8, wherein the ejection of air from the air ejection port is intermittent.   A support roller for supporting the back surface of the liquid crystal display panel whose surface is pressed by the air ejected from the air ejection bar is provided, and the support roller is parallel to the back surface of the liquid crystal display panel by the bar moving means. The foreign object detection device according to claim 7, wherein the foreign object detection device is moved.   The foreign object detection device according to claim 10, wherein a surface of the support roller is white.   The foreign object detection device according to claim 7, wherein the air ejection bar is inclined at a predetermined angle with respect to one side of the liquid crystal display panel.

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