JP4743827B2 - LCD panel visual inspection equipment - Google Patents

Description

  The present invention relates to an appearance inspection apparatus for inspecting the appearance of a liquid crystal panel.

In addition to the so-called lighting inspection to check whether the panel is operating normally, the LCD panel has an appearance inspection to check whether there are any scratches on the panel and whether there is any dirt on the panel. is there. Appearance inspection equipment is a so-called visual appearance inspection device that illuminates the upper surface of a lit or non-lighted liquid crystal panel and the operator visually inspects the panel, and the panel is photographed with a television camera. Thus, a so-called automatic visual inspection apparatus that processes the output signal of the television camera by a computer can be considered, and these are proposed in the following Patent Document 1.
JP-A-10-227721

  The appearance inspection apparatus disclosed in the above-mentioned Patent Document 1 irradiates illumination light from an oblique direction with respect to the surface of the liquid crystal panel, and shoots an image of the liquid crystal panel with an imaging device arranged immediately above the liquid crystal panel. Yes. This visual inspection device uses only a lighting device that illuminates the liquid crystal panel from an oblique direction, so that the visual inspection is performed. Depending on the location and state of scratches and debris on the liquid crystal panel, There is a risk of missing these existences.

  Therefore, in order to solve this problem, the applicant of this application has filed a patent application for an invention in which the lighting condition is devised and the appearance inspection of a plurality of liquid crystal panels is automated by joint application with another company (patent application). 2003-166551 (hereinafter referred to as the prior application). The invention of this prior application is not publicly known at the time of filing of the present application, but since it is closely related to the invention of the present application, its configuration will be briefly described. The appearance inspection device of the prior application is a coaxial illumination device (which irradiates light from above the liquid crystal panel) and an oblique illumination device (irradiates light from an oblique direction with respect to the surface of the liquid crystal panel) as illumination means for visual inspection. And a backlight device. As a result, the lighting state of the liquid crystal panel can be changed in various ways so that the liquid crystal panel can be reliably photographed for scratches and dirt. In addition, a liquid crystal panel reversing device is provided so that when the first surface of the liquid crystal panel is inspected, the second surface on the opposite side can be automatically inspected continuously. This reversing device is composed of two transport devices for transporting the liquid crystal panel from the pre-alignment unit to the inspection unit. In other words, the liquid crystal panel at the inspection position is sucked by one transport device, transferred to the other transport device, and then returned to the inspection position, whereby the liquid crystal panel is inverted.

  The present invention basically solves the problems of the appearance inspection apparatus of Patent Document 1 described above, and its purpose is to remove scratches and dirt on the liquid crystal panel by variously changing the illumination conditions of the liquid crystal panel. An object of the present invention is to provide an appearance inspection apparatus capable of reliably photographing. Another object of the present invention is to adopt a panel reversing device different from the above-mentioned appearance inspection device of the previous application, so that only one conveying device can be used and the conveying device can be used even during reversing work. The object is to provide an appearance inspection apparatus.

The liquid crystal panel appearance inspection apparatus according to the present invention has the following configuration. (A) A pre-alignment device that positions a rectangular liquid crystal panel before inspection. (A) An inspection table that horizontally supports the liquid crystal panel at an inspection position. (C) A transport device that transports the liquid crystal panel from the pre-alignment device to the inspection table. (D) An imaging device that images the liquid crystal panel at the inspection position from a direction parallel to the normal line of the liquid crystal panel. (E) A coaxial illumination device that irradiates light to the liquid crystal panel at the inspection position from a direction substantially parallel to the imaging direction of the imaging device. (F) An oblique illumination device that irradiates light to the liquid crystal panel at the inspection position from four directions inclined with respect to the imaging direction and corresponding to the four sides of the liquid crystal panel. (G) A backlight device that irradiates light from the back to the liquid crystal panel at the inspection position. (H) Four reflecting mirrors arranged to face the four side surfaces of the liquid crystal panel at the inspection position, and reflecting the light from the side surfaces in the direction of the imaging device. (G) A reversing device capable of receiving the liquid crystal panel above the inspection position and reversing the liquid crystal panel, independent of the transport device, and A reversing device comprising (C). (V) A suction pad capable of sucking the liquid crystal panel in a horizontal state above the inspection position with a downward suction surface. (Xi) a reversal arm horizontally extending, rotatable about its axis, reversing arm the suction pad is fixed to the distal end. (F) A rotating device that rotates the reversing arm around a horizontal rotation axis so that the suction surface faces upward. (S) From the suction pad in a state in which the liquid crystal panel at the inspection position can be raised to the downward suction surface and the liquid crystal panel is sucked by the upward suction surface, And a panel lifting / lowering device capable of receiving the liquid crystal panel from below without interfering with the reversing arm and lowering the liquid crystal panel to the inspection position. (C) A lifting / lowering suction surface provided in the panel lifting / lowering device, which is open to the lifting / lowering suction surface and does not interfere with the suction hole for sucking and holding the liquid crystal panel, the suction pad and the reversing arm Elevating suction surface with notches for

  This visual inspection device is equipped with a coaxial illumination device, an oblique illumination device, and a backlight device, so that it can irradiate the liquid crystal panel under various illumination conditions and reliably photograph the liquid crystal panel for scratches and dirt. Can do. In addition, the liquid crystal panel can be transported from the pre-alignment device to the inspection table using the transport device, and the liquid crystal panel at the inspection position can be reversed using the reversing device independent of the transport device. The appearance of multiple LCD panels can be automatically inspected on both sides, and the next LCD panel can be brought up to the pre-alignment device using the transport device during the reversing operation of the LCD panel. it can.

As a preferred embodiment, the transport device includes a plurality of suction pads that can suck and hold the two liquid crystal panels separately. While the appearance of one liquid crystal panel is being inspected at the inspection table, the transfer device can stand by near the inspection table with the next pre-aligned liquid crystal panel held by suction. When the liquid crystal panel that has undergone visual inspection is transferred from the inspection table to one suction pad (vacant suction pad) on the transport device, immediately place the next liquid crystal pad held on another suction pad on the inspection table. be able to. Thereby, the tact time can be shortened.

  As yet another preferred embodiment, the backlight device can be an annular light source surrounding the panel lifting device.

  Since the present invention includes a coaxial illumination device, an oblique illumination device, and a backlight device, the liquid crystal panel can be irradiated with illumination light under various illumination conditions, and the liquid crystal panel can be reliably photographed for scratches and dirt. . Further, the present invention can transport the liquid crystal panel from the pre-alignment device to the inspection table using the transport device, and reverse the liquid crystal panel at the inspection position using the reversing device independent of the transport device. As a result, the appearance of multiple LCD panels can be automatically inspected on both sides, and the next LCD panel can be held up to the pre-alignment device using the transfer device during the reversing operation of the LCD panel. Can come.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an overall configuration of an embodiment of an appearance inspection apparatus according to the present invention, and FIG. 2 is a plan view thereof. 1 and 2, the visual inspection apparatus includes a cassette stage unit 10, a pre-alignment unit 12, an inspection unit 14, and a transport device 16 that transports a liquid crystal panel therebetween. In the plan view of FIG. 2, the imaging and illumination devices located above the inspection unit 14 are removed.

  First, the overall operation of this visual inspection apparatus will be briefly described. In FIG. 1, a cassette 40 containing a plurality of liquid crystal panels 36 is set on the cassette stage unit 10. The first liquid crystal panel 36 in the cassette 40 is taken out by one of the two suction pads of the transport device 16 and then transported to the pre-alignment unit 12 for positioning before inspection. Thereafter, the liquid crystal panel 36 is transported from the pre-alignment unit 12 to the inspection unit 14 by the transport device 16, placed on the inspection table of the inspection unit 14, and held at the inspection position. Illumination light is applied to the surface of the liquid crystal panel 36 at the inspection position (referred to as the first surface), and an image of the liquid crystal panel 36 is taken by the imaging device 98. Next, the liquid crystal panel 36 is reversed by the suction reversing mechanism 60 and returned to the inspection position, and the image is taken by the imaging device 98 also on the opposite side (second surface) of the liquid crystal panel. The image of the imaging device 98 is taken in by a tester, and the quality of the liquid crystal panel is judged.

  On the other hand, while photographing the first and second surfaces of the first liquid crystal panel, the transport device 16 takes out the second liquid crystal panel from the cassette 40 and transports it to the pre-alignment unit 12. Complete pre-alignment work. Then, the transport device 16 holds the second liquid crystal panel for which the pre-alignment work has been completed, and stands by in front of the inspection unit 14. When the photographing of the first and second surfaces of the first liquid crystal panel and the pass / fail determination are completed, the first liquid crystal panel 36 is returned to the original posture (the first surface is upward) by the suction inversion mechanism 60. After that, the liquid crystal panel 36 is delivered to one of the two suction pads of the transport device 16 that is vacant (one that does not suck the liquid crystal panel). Thereafter, the second liquid crystal panel is delivered to the inspection table of the inspection unit 14 from the other suction pad (which holds the second liquid crystal panel by suction) of the transport device 16. Then, the photographing operation for the first and second surfaces of the second liquid crystal panel starts. In the meantime, the conveyance apparatus holding the inspected first liquid crystal panel returns to the cassette stage 40, returns the first liquid crystal panel to the cassette 40, and takes out the third liquid crystal panel from the cassette 40. Thereafter, the appearance inspection of a large number of liquid crystal panels proceeds automatically in the same manner. In this way, while performing the visual inspection of both sides of the liquid crystal panel, the pre-alignment work of the next liquid crystal panel and the conveyance to the vicinity of the inspection unit have been completed. Tact time (inspection cycle when visual inspection of a plurality of liquid crystal panels) is shortened.

  Next, the structure of each part and its function will be described in detail. FIG. 3 is a perspective view of the transfer device 16. The transport device 16 includes a horizontal moving body 18 and a lifting body 20. A horizontal movement guide 22 is fixed to the horizontal moving body 18, and the horizontal movement guide 22 can move in a horizontal direction along a horizontal conveyance rail 24. A lifting rail 28 extending in the vertical direction is fixed to the front surface of the horizontal moving body 18. An elevating guide 26 is fixed to the elevating body 20, and the elevating guide 26 can move in the vertical direction along the elevating rail 28 described above. Here, when the direction of movement is defined, the direction in which the conveyance rail 24 extends is the X direction, the direction perpendicular to the X direction in the horizontal plane is the Y direction, and the vertical direction is the Z direction.

  A central portion of an arm support 30 extending in the X direction is fixed to the elevating body 20, and one end of a transfer arm 32 extending in the Y direction is fixed to each end of the arm support 30. The suction pads 34 are fixed to the tips of the two transfer arms 32, respectively. The suction pad 34 is of a vacuum suction type and has a downward suction surface. In this embodiment, a relatively small liquid crystal panel such as a liquid crystal panel of a cellular phone is handled, and one liquid crystal panel 36 can be sucked and held by one suction pad 34. Therefore, the transport device 16 can suck and hold the two liquid crystal panels 36 separately by using the two suction pads 34.

  FIG. 4 is a perspective view of the cassette stage unit 10. A rectangular cassette 40 can be placed on the upper surface of the rectangular cassette support 38. The cassette 40 is formed with a plurality of recesses 42 for accommodating the liquid crystal panels 36, and one liquid crystal panel 36 can be accommodated in each recess 42. Four corners of the rectangular cassette 40 are clamped by four cassette clamps 44. The cassette clamp 44 can move along a groove 46 extending in the diagonal direction of the cassette 40. Before the cassette 40 is placed on the cassette support 38, the cassette clamp is in an open state as indicated by an imaginary line 44a. When the cassette 40 is placed on the cassette support base 38, the cassette clamp 44 is moved to a predetermined position toward the center of the cassette support base 38, whereby the cassette 40 can be held at the predetermined position. As shown in FIG. 2, the cassette support base 38 can be moved in the direction of the arrow 39 (that is, the Y direction), and the liquid crystal panel 36 accommodated in an arbitrary position of the cassette 40 by this movement and the movement of the transport device 16 in the X direction. Can be sucked by the suction pad 34 of the transport device 16.

  FIG. 5 is a perspective view of the pre-alignment unit 12. A rectangular panel support 50 is fixed on the pre-alignment table 48, and four panel clamps 52 are arranged around it. The outer dimensions of the panel support 50 are smaller than the outer dimensions of the liquid crystal panel 36. When the liquid crystal panel 36 is placed on the panel support 50, the four sides of the liquid crystal panel 36 protrude outward from the four sides of the panel support 50. The four rails 54 are fixed to the pre-alignment table 48 so as to be perpendicular to the four sides of the panel support 50. A guide 56 is fixed to the bottom surface of the panel clamp 52, and the guide 56 can move along the rail 54. When the liquid crystal panel 36 is placed on the panel support base 50 with the four panel clamps 52 opened, and then the panel clamp 52 is moved toward a predetermined position toward the center panel support base 50, the four liquid crystal panels 36 are arranged. One side is pushed to a predetermined position by any two panel clamps 52 according to the protruding state, and finally the liquid crystal panel 36 is positioned at a predetermined position on the panel support 50. What consists of the above-mentioned various components contained in the pre-alignment part 12 corresponds to the pre-alignment apparatus in this invention.

  FIG. 6 is a side view showing the pre-alignment unit 12 and the transport device 16. The liquid crystal panel 36 sucked by the suction pad 34 of the transport device 16 is placed on the panel support 50 of the pre-alignment unit 12 when the elevating body 20 is lowered by the cylinder. Then, the four panel clamps 52 position the liquid crystal panel 36.

  FIG. 7 is a perspective view of the inspection unit. This inspection part is divided into an upper structure and a lower structure. The lower structure is mainly for supporting the liquid crystal panel at the inspection position, and the upper structure is mainly for imaging the liquid crystal panel. First, the substructure will be described. The lower structure includes a panel support portion 58 and a suction inversion mechanism 60. The panel support portion 58 has a structure for supporting the liquid crystal panel 36 at the inspection position, and further includes a reflection mirror 62 for imaging the side surface of the liquid crystal panel 36. Details thereof will be described later.

  FIG. 8 is a perspective view of the suction inversion mechanism 60. The suction reversing mechanism 60 includes a rail 64, a moving body 66, a rotary actuator 68, a reversing arm 70, and a suction pad 72. The rail 64 is fixed to the base plate 74 of the panel support portion 58. A guide 76 moves along the rail 64, and a moving body 66 is fixed to the guide 76. A rotating actuator 68 is fixed to the moving body 66, and the rotating arm 68 rotates the reversing arm 70 about its axis (extending horizontally). The reversing arm 70 extends in the Y direction, and a vacuum suction type suction pad 72 is fixed to the tip thereof. The reversing arm 70 can be rotated forward and backward by an angle of 180 degrees around its axis, and by this rotation, the suction surface of the suction pad 72 can be changed from downward to upward and from upward to downward. it can.

  FIG. 9 is a side view of the suction reversing mechanism 60 and the panel support portion 58. The moving body 66 of the suction reversing mechanism 60 can move along the rail 64 in the Y direction (left-right direction in the figure). FIG. 9A shows a state where the suction reversing mechanism 60 is in the retracted position, and FIG. 9B shows a state where the suction reversing mechanism 60 is in the operating position (position where the liquid crystal panel is reversed). Yes. In this operating position, the suction pad 72 is positioned directly above a panel lifter 82 described later.

  10 is a cross-sectional view of the panel support portion 58, and is a cross-sectional view taken along the line AA of FIG. The panel support portion 58 includes a base plate 76. A rectangular work table 78 that does not transmit light is fixed to the center of the base plate 76, and a rectangular diffuser plate 80 that transmits light is fixed to the center of the work table 78. A through hole is formed at the center of the diffusion plate 80, and the panel lifter 82 passes through the through hole. The panel lifter 82 corresponds to the panel lifting device in the present invention. An annular backlight device 84 is disposed below the diffusion plate 80. The backlight device 84 is accommodated in the casing 85. A through hole is also formed in the center of the bottom wall of the casing 85, and the panel lifter 82 passes through this through hole. The upper surface of the panel lifter 82 is an inspection table 86 (see also FIG. 12), and this inspection table 86 is an ascending / descending adsorption surface. An adsorption hole 87 (see FIG. 12) is opened on the lift adsorption surface, and the liquid crystal panel 36 can be adsorbed and held by the adsorption hole 87. A notch 83 (see also FIG. 12) is formed in the vicinity of the upper portion of the panel lifter 82, and the notch 83 is exposed on the lift adsorption surface. The role of the notch 83 will be described later. The panel lifter 82 can be moved up and down by a cylinder (not shown). Four reflecting mirrors 62 are fixed on the upper surface of the work table 78. In FIG. 10, the rotary actuator 68, the arm 70, and the suction pad 72 of the suction reversing mechanism 60 are visible above the inspection table 86.

  FIG. 11 is a cross-sectional view showing the operation of the suction reversing mechanism 60 and the panel lifter 82, and is a part of the cross section cut along the line AA in FIG. In FIG. 11A, the liquid crystal panel 36 is placed on the inspection table 86 and is in the inspection position. When the appearance inspection of the first surface of the liquid crystal panel 36 is completed, the panel lifter 82 is raised to bring the liquid crystal panel 36 into contact with the suction surface of the downward suction pad 72 as shown in FIG. The suction pad 72 vacuum-sucks the first surface (surface that has undergone appearance inspection) of the liquid crystal panel 36. Thereafter, as shown in FIG. 11C, the panel lifter 82 descends, and then the reversing arm 70 rotates clockwise by 180 degrees around its axis. By this rotation, the downward suction pad 72 is directed upward while the liquid crystal panel 36 is held by suction. The liquid crystal panel 36 has a second surface (a surface opposite to the first surface) facing upward. Next, as shown in FIG. 11 (D), the panel lifter 82 is raised, and the inspection table 86 on the upper surface comes into contact with the first surface of the liquid crystal panel 36. When the panel lifter 82 is further raised, the liquid crystal panel 36 moves from the suction pad 72 to the inspection table 86 on the upper surface of the panel lifter 82. At this time, since the notch 83 of the panel lifter 82 passes through the suction pad 72 and the reversing arm 70, the panel lifter 82 does not collide with the suction pad 72 and the arm 79. When the liquid crystal panel 36 moves to the panel lifter 82, the suction inversion mechanism returns to the retracted position shown in FIG. Then, the panel lifter 82 is lowered and the inverted liquid crystal panel 36 returns to the inspection position shown in FIG. Thereafter, an appearance inspection of the second surface of the liquid crystal panel 36 is performed. The panel lifter 82 corresponds to the panel lifting device in the present invention.

  The liquid crystal panel 36 having undergone the appearance inspection of the second surface is inverted again by the procedure of FIGS. 11A to 11C, and the first surface is directed upward. Thereafter, as shown in FIG. 18, the liquid crystal panel 36 held by the upward suction pad 72 is received by the downward suction pad 34 of the transport arm 32. Then, the inspected liquid crystal panel 36 is returned to the cassette stage section.

  Next, the imaging system and illumination system of the inspection unit will be described. Returning to FIG. 7, a backlight device 84 (see FIG. 10) among the three types of illumination devices is provided in the lower structure of the inspection unit. A coaxial illumination device 88 and an oblique illumination device 90 among the three types of illumination devices are provided in the upper structure of the inspection unit. The lighting box 92 has a cylindrical shape with a horizontal cross section, and an upper end and a lower end are open. A coaxial illumination device 88, a shutter 94, and a half mirror 96 are disposed inside the illumination box 92. An oblique illumination device 90 is fixed near the lower end of the illumination box 92. An imaging device 98 is disposed above the illumination box 92. The imaging device 98 is a CCD camera and includes a focus adjustment mechanism. By taking the image of the image pickup device 98 into an image processing device (tester), this image is used for judging the quality of the liquid crystal panel. The imaging direction (vertical direction) of the imaging device 98 is parallel to the normal of the surface of the liquid crystal panel 36 (which also extends in the vertical direction).

  FIG. 13 is a perspective view showing the coaxial illumination device 88 and the shutter 94. FIG. 13A shows a state where the shutter 94 is closed, and FIG. 13B shows a state where the shutter 94 is opened. In FIG. 13A, the coaxial illumination device 88 is composed of a plurality of fluorescent tubes. The shutter 94 is an upright rectangular flat plate and is disposed between the coaxial illumination device 88 and the half mirror 96 (see FIG. 7). The shutter 94 is opened and closed by driving the shutter 94 up and down by a cylinder.

  FIG. 12 is a perspective view showing the structure on the work table 78 and the oblique illumination device 90 in the inspection section. Four reflecting mirrors 62 are provided on the work table 78. The reflecting surfaces of these reflecting mirrors 62 are inclined by 45 degrees with respect to the horizontal plane. The four reflecting mirrors 62 are provided corresponding to the four sides of the rectangular liquid crystal panel 36. The upper part of the panel lifter 82 protrudes from the central through hole of the diffusion plate 80, and two suction holes 87 are formed in the inspection table 86 on the upper surface. A notch 83 at the top of the panel lifter 82 is also visible. The liquid crystal panel 36 is sucked and held in the suction hole 87. FIG. 12 shows a state in which the liquid crystal panel 36 is held at the inspection position.

  An oblique illumination device 90 is fixed near the lower end of the illumination box 92. The oblique illumination device 90 includes an oblique lamp 104 made of four LEDs (light emitting diodes). These oblique light lamps 104 are provided corresponding to the four sides of the liquid crystal panel 36, and illuminate the surface of the liquid crystal panel 36 from four oblique directions.

  14 is a side cross-sectional view of the inspection unit, and is a cross-sectional view taken along line BB in FIG. The suction reversal mechanism is omitted. FIG. 14 shows a situation in which the liquid crystal panel 36 is observed using only illumination light from the coaxial illumination device 88. The shutter 94 is open, and part of the light 106 emitted from the coaxial illumination device 88 is reflected by the half mirror 96 and travels downward. The half mirror 96 is inclined at an angle of 45 degrees with respect to the horizontal plane. The light reflected near the center of the half mirror 96 reaches the surface of the liquid crystal panel 36 and illuminates the surface of the liquid crystal panel 36. The light reflected in the vicinity of the four sides of the rectangular half mirror 96 is directed to the four reflecting mirrors 62 and is reflected there to illuminate the four side surfaces of the liquid crystal panel 36.

  The light emitted from the surface of the liquid crystal panel 36 (this is the illumination light reflected from the panel surface and becomes the image light on the surface) proceeds directly upward, and part of the light passes through the half mirror 96. The light passes through and reaches the imaging device 98. The light emitted from the four side surfaces of the liquid crystal panel 36 (this is the total of the illumination light reflected from the side surface of the panel and the illumination light transmitted from the opposite side surface direction, Is reflected by the reflecting mirror 62 and travels upward, and part of the light passes through the half mirror 96 and reaches the imaging device 98. In this way, the surface image and the four side images of the liquid crystal panel 36 illuminated by the illumination light from the coaxial illumination device 88 are photographed by the imaging device 98. The direction in which the illumination light from the coaxial illumination device 88 is directed to the liquid crystal panel 36 and the direction in which the image light from the liquid crystal panel 36 is directed to the imaging device 98 are substantially parallel and substantially overlap each other. Therefore, such illumination light is called coaxial illumination, and the illumination device for that purpose is called coaxial illumination device.

  FIG. 16 shows the outer shape of an image obtained by the imaging apparatus. There is an image 108 of the surface of the liquid crystal panel at the center, and images 110 of four side surfaces of the liquid crystal panel so as to surround it. The side image 110 is taken by the imaging device after being reflected by the reflecting mirror.

  FIG. 15 is a side sectional view showing another illumination state of the inspection unit shown in FIG. This drawing shows a situation in which the liquid crystal panel 36 is observed using only illumination light from the oblique illumination device 90. Although the coaxial illumination device 88 is in a lighting state, the coaxial illumination light does not strike the liquid crystal panel 36 because the shutter 94 is closed. If the coaxial illumination device 88 is turned off when the coaxial illumination is not used, the shutter 94 is unnecessary. However, in reality, the coaxial illumination device 88 is turned on and off by turning on and off the shutter 94 while the coaxial illumination device 88 is turned on. Is switched. The reason is that the coaxial illumination device 88 is composed of a fluorescent tube, and it takes time until the luminance is stabilized.

  The four oblique lamps 104 of the oblique illumination device 90 emit illumination light 112 from four oblique directions with respect to the liquid crystal panel 36 (that is, from four directions inclined with respect to the normal of the surface of the liquid crystal panel 36). Irradiating. The four directions correspond to the four sides of the liquid crystal panel 36. The normal line of the surface of the oblique lamp 104 is inclined within a range of 30 to 60 degrees with respect to the normal line of the surface of the liquid crystal panel 36. When the oblique illumination device 90 is used, light strikes the liquid crystal panel 36 from a direction different from that in the case of the coaxial illumination. Is done. Also in this case, an image as shown in FIG.

  In FIG. 15, there is a method of using a backlight device 84 as a third illumination method. When only the illumination light of the backlight device 84 is used, the shutter 94 is closed and the oblique illumination device 90 is turned off. Illumination light from the backlight device 84 is diffused by the diffusing plate 80 and passes through the diffusing plate 80 to be uniform light and illuminate the back surface of the liquid crystal panel 36. The light transmitted through the liquid crystal panel 36 is photographed by the imaging device 98. When this backlight device 84 is used, scratches inside the liquid crystal panel 36 become clear. The diffuser plate 80 is black to prevent reflection. That is, the coaxial illumination light is not reflected by the diffuser plate 80. The backlight device 84 is made of LED and lights up only when necessary.

  A total of six lighting fixtures including the coaxial illumination device 88, the four oblique light lamps 104, and the backlight device 84 can be turned on / off independently (however, the coaxial illumination device 88 is controlled by a shutter). However, by combining the lighting and extinguishing states of these lighting fixtures, defects in the liquid crystal panel can be clearly projected under various lighting conditions. Thereby, the reliability of the judgment of the quality of appearance by automatic inspection is increased. Items found in this visual inspection include, for example, glass defects (for example, cracks and chips), polarizing plate defects (for example, turning over), liquid crystal sealing materials, electrode parts, and protective sheets. There is.

  FIG. 17 is an enlarged view of a part of a video example of the imaging apparatus. If the glass plate of the liquid crystal panel is scratched and the scratch extends to the inside of the glass plate, an image of the scratch as shown in FIG. 17 is taken. The size of the scratch 112 can be grasped from the image 108 on the panel surface. In the right side image 110a and the back side image 110b, the depth d of the flaw can be grasped.

  In the above-described embodiment, the liquid crystal panel is illustrated as being square, but may be rectangular. In the case of a rectangular liquid crystal panel, for example, the lengths of the reflection mirror 62 and the oblique lamp 104 are preferably changed according to the short side or the long side length of the liquid crystal panel 36.

It is a perspective view which shows the whole structure of one Example of the external appearance inspection apparatus of this invention. It is a top view of the external appearance inspection apparatus shown in FIG. It is a perspective view of a conveying apparatus. It is a perspective view of a cassette stage part. It is a perspective view of a pre-alignment part. It is a side view which shows a pre-alignment part and a conveying apparatus. It is a perspective view of an inspection part. It is a perspective view of a suction inversion mechanism. It is a side view which shows two states of an adsorption | suction inversion mechanism and a panel support part. It is sectional drawing of a panel support part, and is the sectional view on the AA line of FIG. It is sectional drawing which shows a series of operation | movement of an adsorption | suction inversion mechanism and a panel lifter, and is a part of cross section cut | disconnected by the AA line of FIG. It is a perspective view which shows the structure on the work table in a test | inspection part, and an oblique illumination apparatus. It is a perspective view which shows a coaxial illuminating device and a shutter. It is side surface sectional drawing of an test | inspection part, and is the BB sectional drawing of FIG. It is side surface sectional drawing which shows another illumination state of the test | inspection part shown in FIG. It is an image figure which shows the external shape of the image | video obtained with an imaging device. 2 is an enlarged view of a part of a video example of an imaging apparatus. It is a side view which shows delivery of the liquid crystal panel from a suction inversion mechanism to a conveying apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cassette stage part 12 Pre-alignment part 14 Inspection part 16 Conveyance apparatus 32 Conveyance arm 34 Adsorption pad 36 Liquid crystal panel 48 Pre-alignment table 50 Panel support stand 52 Panel clamp 58 Panel support part 60 Adsorption reversing mechanism 62 Reflection mirror 66 Moving body 68 Rotation Actuator 70 Reverse arm 72 Suction pad 80 Diffusion plate 82 Panel lifter 84 Backlight device 86 Inspection table 88 Coaxial illumination device 90 Oblique illumination device 92 Illumination box 94 Shutter 96 Half mirror 98 Imaging device 104 Oblique light lamp

Claims (4)

A liquid crystal panel appearance inspection apparatus having the following configuration.
(A) A pre-alignment device that positions a rectangular liquid crystal panel before inspection.
(A) An inspection table that horizontally supports the liquid crystal panel at an inspection position.
(C) A transport device that transports the liquid crystal panel from the pre-alignment device to the inspection table.
(D) An imaging device that images the liquid crystal panel at the inspection position from a direction parallel to the normal line of the liquid crystal panel.
(E) A coaxial illumination device that irradiates light to the liquid crystal panel at the inspection position from a direction substantially parallel to the imaging direction of the imaging device.
(F) An oblique illumination device that irradiates light to the liquid crystal panel at the inspection position from four directions inclined with respect to the imaging direction and corresponding to the four sides of the liquid crystal panel.
(G) A backlight device that irradiates light from the back to the liquid crystal panel at the inspection position.
(H) Four reflecting mirrors arranged to face the four side surfaces of the liquid crystal panel at the inspection position, and reflecting the light from the side surfaces in the direction of the imaging device.
(G) A reversing device capable of receiving the liquid crystal panel above the inspection position and reversing the liquid crystal panel, independent of the transport device, and A reversing device comprising (C).
(V) A suction pad capable of sucking the liquid crystal panel in a horizontal state above the inspection position with a downward suction surface.
(Xi) a reversal arm horizontally extending, rotatable about its axis, reversing arm the suction pad is fixed to the distal end.
(F) A rotating device that rotates the reversing arm around a horizontal rotation axis so that the suction surface faces upward.
(S) From the suction pad in a state in which the liquid crystal panel at the inspection position can be raised to the downward suction surface and the liquid crystal panel is sucked by the upward suction surface, And a panel lifting / lowering device capable of receiving the liquid crystal panel from below without interfering with the reversing arm and lowering the liquid crystal panel to the inspection position.
(C) A lifting / lowering suction surface provided in the panel lifting / lowering device, which is open to the lifting / lowering suction surface and does not interfere with the suction hole for sucking and holding the liquid crystal panel, the suction pad and the reversing arm Elevating suction surface with notches for 2. The liquid crystal panel appearance inspection apparatus according to claim 1 , wherein a diffusion plate is disposed between the liquid crystal panel at the inspection position and the backlight device, and an upper surface of the panel lifting device constitutes the inspection table. An apparatus for inspecting the appearance of a liquid crystal panel, wherein the panel lifting device moves up and down through the diffusion plate. 3. The liquid crystal panel appearance inspection apparatus according to claim 1 , wherein the transport device includes a plurality of suction pads that can suck and hold the two liquid crystal panels separately. 4. Inspection device. In the appearance inspection apparatus for liquid crystal panel according to any one of claims 1 to 3, wherein the backlight device, the appearance of the liquid crystal panel, characterized in that it comprises an annular light source which surrounds the panel lifting device Inspection device.

Images