KR100654218B1 - Apparatus For Inspecting External Appearance Of Liquid Crystal Panel - Google Patents

Abstract

The apparatus for inspecting the appearance of a liquid crystal panel according to the present invention is to make it possible to reliably photograph wounds and dust of the liquid crystal panel by changing various lighting conditions. In addition, by devising a panel reversing apparatus, the conveying apparatus can be used between the reversing operations at the same time as one conveying apparatus is finished. The liquid crystal panel 36 is conveyed from the prealignment part 12 to the test | inspection part 14 using the conveyance apparatus 16. FIG. The liquid crystal panel 36 at the inspection position is irradiated with light from the illumination device and photographed by the imaging device 98. The illumination device includes a coaxial illumination device 88 for irradiating light from a direction parallel to the imaging direction, a projection light illuminator 90 for irradiating light from a direction inclined with respect to the imaging direction, and light from the back of the liquid crystal panel. There is a backlight device 84 for irradiating light. Images of the four sides of the liquid crystal panel may be photographed through the reflection mirror 62. The liquid crystal panel 36 can be inverted using the inversion device 60 independent of the conveying apparatus 16, and the imaging of both surfaces of the liquid crystal panel 36 becomes possible.

LCD panel, visual inspection device, lighting device, imaging device, inverting device

Description

Apparatus For Inspecting External Appearance Of Liquid Crystal Panel}

1 is a perspective view showing the overall configuration of an embodiment of an appearance inspection apparatus of the present invention.

FIG. 2 is a plan view of the appearance inspection apparatus shown in FIG.

3 is a perspective view of the conveying apparatus.

4 is a perspective view of a cassette stage portion.

5 is a perspective view of a prealignment unit.

6 is a side view showing a prealignment unit and a conveying apparatus.

7 is a perspective view of the inspection unit.

8 is a perspective view of the adsorption inversion mechanism.

9 is a side view showing two states of the adsorption inversion mechanism and the panel support.

Fig. 10 is a sectional view of the panel support section, taken along line A-A in Fig. 2;

FIG. 11 is a sectional view showing a series of operations of the adsorption inversion mechanism and the panel lifter, and is a part of a cross section cut along the line A-A of FIG.

Fig. 12 is a trial showing the structure on the work table in the inspection unit and the projection lighting apparatus.

Fig. 13 is a perspective view showing a coaxial illuminator and a shutter.

14 is a side cross-sectional view of the inspection unit, and a cross-sectional view taken along line B-B in FIG.

FIG. 15 is a side sectional view showing another illumination state of the inspection unit shown in FIG.

Fig. 16 is an image diagram showing an external appearance of an image obtained by the imaging device.

17 is an enlarged view of a part of an image example of an imaging device.

Fig. 18 is a side view showing the water supply of the liquid crystal panel from the adsorption inversion mechanism to the transport apparatus.

Description of the main symbols in the drawings

10: cassette stage portion 12: pre-alignment portion

14: Inspection unit 16: Transfer device

32: return arm 34: adsorption pad

36: liquid crystal panel 48: pre-alignment table

50: panel support 52: panel clamp

58: panel support 60: adsorption inversion mechanism

62: reflective mirror 66: moving object

68: rotary actuator 70: inverting arm

72: adsorption pad 80: diffusion plate

82: panel lifter 84: backlight device

86: test bench 88: coaxial lighting device

90: dead light illuminator 92: light box

94: shutter 96: half miller

98: imaging device 104: projection lamp

Field of invention

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

Background of the Invention

In addition to the so-called lighting test of whether or not the panel operates normally, the inspection of the liquid crystal panel includes an external inspection that examines whether there is no scratch on the panel, dust is not adhered to the panel, and the like. As an external appearance inspection apparatus, a so-called visual appearance inspection apparatus which irradiates the upper surface of a liquid crystal panel in a lit state or a non-lit state and visually inspects the panel by a worker, and photographs the panel with a television camera, A so-called automatic appearance inspection apparatus that processes the output signal of a television camera with a computer is considered, and they are proposed in the following patent document 1.

Patent Document 1: Japanese Patent Application Laid-Open No. 10-227721

The external appearance inspection apparatus disclosed in the above-mentioned patent document 1 irradiates illumination light to the surface of a liquid crystal panel in the inclination direction, and image | photographs the image of a liquid crystal panel with the imaging device arrange | positioned directly on the liquid crystal panel. Since the appearance inspection apparatus inspects the appearance only by using an illumination device of a type that emits light in an inclined direction with respect to the liquid crystal panel, the existence thereof may be overlooked depending on the position or the state of the scratch or dust of the liquid crystal panel. There is a concern.

Therefore, in order to solve this problem, the applicant of the present application has filed a patent for an invention which devised an illumination state by a joint application with a third party, and also automated the inspection of the appearance of a plurality of liquid crystal panels (Japanese Patent Application No. 2003-166551). (Hereinafter referred to as crew). Although this source invention is not known at the time of this application, since it is deeply related to the invention of this application, the structure is simply mentioned. The source inspection apparatus of the source is a lighting means for inspecting the exterior, which is a coaxial illuminator (irradiating light from above the liquid crystal panel) and an oblique illuminator (irradiating light from an oblique direction to the surface of the liquid crystal panel). And backlit devices. Thereby, the illumination state of a liquid crystal panel can be changed in various ways, and the wound and the dust of a liquid crystal panel can be taken reliably. In addition, the inverting device of the liquid crystal panel is provided, and when the external inspection of the first surface of the liquid crystal panel is performed, the second surface on the opposite side can be continuously and automatically inspected. The said reverse device is comprised by two conveying apparatuses for conveying a liquid crystal panel from a prealignment part to an inspection part. In other words, the liquid crystal panel at the inspection position is sucked by one conveying device, passed to the other conveying apparatus, and then returned to the inspection position, thereby inverting the liquid crystal panel.

This invention basically solves the problem of the external appearance inspection apparatus of patent document 1 mentioned above, The objective is being able to reliably photograph the wound and the dust of a liquid crystal panel by changing lighting conditions of a liquid crystal panel in various ways. It is to provide an appearance inspection apparatus. Another object of the present invention is to provide an external appearance inspection apparatus which employs a panel reversal apparatus different from the above-described external appearance inspection apparatus, which allows the transfer apparatus to be used between reversal operations while completing one transfer apparatus. .

The above and other objects of the present invention can be achieved by the present invention described below. Hereinafter, the content of the present invention will be described in detail.

The external appearance inspection apparatus of the liquid crystal panel which concerns on this invention is provided with the structure of following (1)-(9). (1) a pre-alignment device for positioning a rectangular liquid crystal panel before inspection, (2) an inspection table for supporting the liquid crystal panel at an inspection position, and (3) a conveying device for conveying the liquid crystal panel from the pre-alignment apparatus to the inspection zone. (4) an imaging device for imaging the liquid crystal panel at the inspection position from a direction parallel to the normal of the liquid crystal panel, (5) from the direction parallel to the imaging direction of the imaging device to the inspection position. A coaxial illuminating device for irradiating light to a liquid crystal panel having a light; (6) irradiating light to the liquid crystal panel at the inspection position from four directions corresponding to four sides of the liquid crystal panel as four directions inclined with respect to the imaging direction; (7) a backlight unit for irradiating light from the rear surface of the liquid crystal panel at the inspection position; (8) a rear face facing the four sides of the liquid crystal panel at the inspection position. Four reflecting mirrors, a reflecting mirror for reflecting light from the side surface in the direction of the imaging device, and (9) an inverting mirror that can receive the liquid crystal panel from above the inspection position and invert the liquid crystal panel. An inverting device independent of the conveying device as a device.

Since the external appearance inspection apparatus is provided with a coaxial illuminator, a four-beam illuminator and a backlight device, the illuminating light can be irradiated to the liquid crystal panel under various lighting conditions, thereby making it possible to reliably photograph the wound and the dust of the liquid crystal panel. In addition, since the liquid crystal panel can be conveyed from the prealignment apparatus to the inspection stand using the conveying apparatus, and the liquid crystal panel at the inspection position can be inverted by using an inverting apparatus independent of the conveying apparatus, a plurality of liquid crystal panels can be used. Both surfaces can be inspected automatically, and the next liquid crystal panel can be brought to the pre-alignment device by using the conveying device between the inverting operations of the liquid crystal panel.

As a preferable aspect, the appearance inspection apparatus can be configured to support the liquid crystal panel horizontally at the inspection position, in which case the inversion apparatus has the following configurations (10) to (12). Can be. (10) an adsorption pad capable of adsorbing the liquid crystal panel in a horizontal state above the inspection position to a downward adsorption surface, and (11) rotating the adsorption pad around a horizontal axis of rotation so that the adsorption surface is directed upwards; The rotating device (12) can raise the liquid crystal panel at the inspection position downward to the adsorption surface, and furthermore, without interfering with the adsorption pad from the adsorption pad in a state where the liquid crystal panel is adsorbed onto the adsorption surface upward. And a panel elevating device capable of receiving the liquid crystal panel and lowering the liquid crystal panel to the inspection position.

As another preferred aspect, the panel elevating device has a lifting and lowering suction surface on which suction holes for holding and holding the liquid crystal panel are opened, and the lifting and lowering suction surface is provided with a cutout not to interfere with the suction pad. When the panel elevating device receives the liquid crystal panel from the uptake pad of the inverter, the uptake pad enters the gap, and the panel elevating device does not interfere with the adsorption pad.

As another preferable aspect, the conveying apparatus is provided with a plurality of adsorption pads capable of adsorbing and holding two liquid crystal panels separately. While the single liquid crystal panel is inspected externally by the inspection table, the conveying apparatus can be pre-aligned and then stand by near the inspection table while the liquid crystal panel is adsorbed and held. If the liquid crystal panel that has been visually inspected can be transferred from the inspection table to one adsorption pad (empty adsorption pad) of the conveying device, the next liquid crystal panel supported by the other adsorption pad can be placed on the inspection table. As a result, the tact time can be shortened.

As another preferable aspect, a backlight device can be set as the annular light source which surrounds a panel lifting device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a perspective view showing the overall configuration of an embodiment of an appearance inspection apparatus of the present invention, and Fig. 2 is a plan view thereof. 1 and 2, the visual inspection apparatus includes a cassette stage portion 10, a prealignment portion 12, an inspection portion 14, and a conveying apparatus 16 for conveying a liquid crystal panel between them. In addition, in the top view of FIG. 2, it shows except the imaging and lighting apparatus located in the upper part of the test | inspection part 14. As shown in FIG.

First, the overall operation of the visual inspection apparatus will be described briefly. In Fig. 1, a cassette 40 containing a plurality of liquid crystal panels 36 is set in the cassette stage section 10. As shown in Figs. The first liquid crystal panel 36 in the cassette 40 is taken out by one of the two adsorption pads of the conveying device 16, and then conveyed to the prealignment unit 12, and positioning before inspection is performed. Thereafter, the liquid crystal panel 36 is conveyed from the prealignment portion 12 to the inspection portion 14 by the transfer device 16, placed on the inspection table of the inspection portion 14, and held at the inspection position. Illumination light is irradiated onto the surface of the liquid crystal panel 36 (which is called the first surface) at the inspection position, and an image of the liquid crystal panel 36 is captured by the imaging device 98. Subsequently, the liquid crystal panel 36 is inverted and returned to the inspection position by the adsorption inversion mechanism 60, and the image is captured by the imaging device 98 on the opposite side (second surface) of the liquid crystal panel. The image of the image capturing apparatus 98 is put into a tester (not shown) to make a defect determination of the liquid crystal panel.

On the other hand, while imaging the 1st surface and the 2nd surface with respect to the 1st liquid crystal panel, the conveying apparatus 16 takes out the 2nd liquid crystal panel from the cassette 40, and conveys it to the prealignment part 12. FIG. And complete the pre-alignment operation. And the conveying apparatus 16 supports the 2nd liquid crystal panel in which the pre-alignment operation | work completed, and waits in front of the inspection part 14. As shown in FIG. When the photographing and the defect determination of the first and second surfaces of the first liquid crystal panel are completed, the first liquid crystal panel 36 is originally viewed by the adsorption inversion mechanism 60 (the first surface faces upward). The liquid crystal panel 36 is returned to the empty side (the side which does not adsorb the liquid crystal panel) among the two adsorption pads of the conveyance apparatus 16 after returning to the (). Thereafter, the second liquid crystal panel is passed from the other adsorption pad (which holds the second liquid crystal panel to be adsorbed) of the conveying device 16 to the inspection section of the inspection unit 14. Then, the photographing operation of the first and second surfaces of the second liquid crystal panel is started. In the meantime, the conveyance apparatus which supported the 1st liquid crystal panel after completion | finish of inspection returns to the cassette stage 40, returns a 1st liquid crystal panel to the cassette 40, and simultaneously inserts a 3rd liquid crystal panel into a cassette ( 40). Thereafter, in the same manner, the external appearance inspection of the plurality of liquid crystal panels proceeds automatically. Thus, while performing the external alignment inspection of both sides of a liquid crystal panel, since the pre-alignment operation of the next liquid crystal panel and conveyance to the vicinity of a test | inspection part are completed, the tact time (plural liquid crystal in the case of external appearance inspection of several liquid crystal panels) The inspection cycle when the panel is inspected externally is shortened.

Next, the structure of each part and its effect are demonstrated in detail. 3 is a perspective view of the conveying device 16. The conveying apparatus 16 includes a horizontal movable body 18 and a lifting body 20. The horizontal moving guide 22 is fixed to the horizontal moving body 18, and the horizontal moving guide 22 can move in the horizontal direction along the 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 up and down along the elevating rail 28 described above. Here, defining the moving direction, 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 up and down direction is the Z direction.

The center portion of the arm support body 30 extending in the X direction is fixed to the lifting body 20, and one end of the transfer arm 32 extending in the Y direction is fixed to both ends of the arm support body 30, respectively. Adsorption pads 34 are respectively fixed to the ends of the two transfer arms 32. The suction pad 34 is vacuum suction type and has a downward suction surface. This embodiment handles a relatively small liquid crystal panel such as a liquid crystal panel of a mobile phone, and can adsorb and hold one liquid crystal panel 36 with one suction pad 34. Therefore, the conveying apparatus 16 can adsorb | suck and hold two liquid crystal panels 36 separately by using the two adsorption pads 34. As shown in FIG.

4 is a perspective view of the cassette stage portion 10. The rectangular cassette 40 may be placed on the upper surface of the rectangular cassette support 38. The cassette 40 is provided with a plurality of recesses 42 for accommodating the liquid crystal panel 36, and each of the recesses 42 can accommodate one liquid crystal panel 36. The four corners of the rectangular cassette 40 are clamped by four cassette clamps 44. The cassette clamp 44 can move along the groove 46 extending in the diagonal direction of the cassette 40. Prior to placing the cassette 40 on the cassette support 38, the cassette clamp is in the open state as indicated by the imaginary line 44a. When the cassette 40 is placed on the cassette support 38, the cassette clamp 44 is moved to the predetermined position toward the center of the cassette support 38, whereby the cassette 40 can be held at the predetermined position. As shown in Fig. 2, the cassette support 38 can move in the direction of the arrow 39 (i.e., the Y direction), and by this movement and the movement of the conveying apparatus 16 in the X direction, any of the cassettes 40 can be moved. The liquid crystal panel 36 accommodated in the position of can be adsorbed by the adsorption pad 34 of the conveying apparatus 16.

5 is a perspective view of the prealignment unit 12. A rectangular panel support 50 is fixed on the prealignment table 48, and four panel clamps 52 are arranged around the prealignment table 48. The external dimension of the panel support 50 is smaller than the external dimension of the liquid crystal panel 36. When the liquid crystal panel 36 is placed on the panel support 50, four sides of the liquid crystal panel 36 protrude outward from the four sides of the panel support 50. Four rails 54 are fixed to the prealignment table 48 so as to be perpendicular to the four sides of the panel support 50. A guide 56 is fixed to the bottom of the panel clamp 52, and the guide 56 may move along the rail 54. The liquid crystal panel 36 is placed on the panel support 50 with the four panel clamps 52 open, and then the panel clamp 52 is moved to a predetermined position toward the center panel support 50. The four sides of the panel 36 are pressed 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. do. The pre-alignment apparatus in this invention comprised with the various components mentioned above contained in the pre-alignment part 12 is corresponded.

6 is a side view illustrating the prealignment unit 12 and the transport apparatus 16. The liquid crystal panel 36 adsorbed by the adsorption pad 34 of the conveying device 16 is placed on the panel support 50 of the prealignment part 12 by the lifting body 20 descending by the cylinder. Four panel clamps 52 position the liquid crystal panel 36.

7 is a perspective view of the inspection unit. The 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 lower structure will be described. The lower structure includes a panel support 58 and a suction reversal mechanism 60. The panel support 58 has a structure for supporting the liquid crystal panel 36 at the inspection position, and also has a reflective mirror 62 for imaging the side surface of the liquid crystal panel 36. Their details will be described later.

8 is a perspective view of the adsorption inversion mechanism 60. The adsorption inversion mechanism 60 includes a rail 64, a moving body 66, a rotary actuator 68, an inversion arm 70, and an adsorption pad 72. The rail 64 is fixed to the base plate 74 of the panel support 58. The guide 76 is made to move along the said rail 64, and the moving body 66 is being fixed to the guide 76. As shown in FIG. The rotary actuator 68 is fixed to the movable body 66, and the reversal arm 70 rotates around its axis (horizontally extending) by the rotary actuator 68. The inversion arm 70 extends in the Y direction, and the vacuum adsorption | suction adsorption pad 72 is fixed to the front-end | tip. The inverting arm 70 can be rotated forward and backward by an angle of 180 degrees around its axis, and by this rotation, the adsorption surface of the adsorption pad 72 is moved from downward to upward and downward from upward. You can switch to

9 is a side view of the suction reversal mechanism 60 and the panel support 58. The moving body 66 of the adsorption inversion mechanism 60 can move along the rail 64 in the Y direction (left and right directions in the drawing). 9 (A) shows the state in which the adsorption inversion mechanism 60 is in the retracted position, and in FIG. 9 (B), the adsorption inversion mechanism 60 is in the operating position (the position in which the liquid crystal panel is inverted). Indicates a state of. In this operating position, the suction pad 72 is located directly above the panel lifter 82 described later.

FIG. 10 is a sectional view of the panel support 58, and is a sectional view taken along the line A-A of FIG. The panel support 58 has a base plate 76. In the center of the base plate 76, a rectangular work table 78 through which light is not transmitted is fixed, and in the center of the work table 78, a rectangular diffuser plate 80 through which light is transmitted is fixed. A through hole is formed in the center of the diffusion plate 80, and the panel lifter 82 penetrates 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 housed inside the casing 85. A through hole is formed in the center of the bottom wall of the casing 85, and the panel lifter 82 penetrates the through hole. The upper surface of the panel lifter 82 is an inspection table 86 (see also FIG. 12), and the inspection table 86 is a lifting suction surface. A suction hole 87 (see FIG. 12) is opened in the lifting suction surface, and the liquid crystal panel 36 can be sucked and held by the suction hole 87. A flaw 83 (see FIG. 12) is formed near the upper portion of the panel lifter 82, and the flaw 83 is exposed to the lifting suction surface. The role of the said notch 83 is mentioned later. The panel lifter 82 can be elevated by a cylinder (not shown). Four reflective mirrors 62 are fixed to the upper surface of the work table 78. In FIG. 10, the rotary actuator 68, the arm 70, and the adsorption pad 72 of the adsorption inversion mechanism 60 are shown above the inspection table 86.

FIG. 11 is a cross-sectional view showing the operation of the adsorption inversion mechanism 60 and the panel lifter 82, and is a part of a cross section cut along the line A-A 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 external inspection of the first surface of the liquid crystal panel 36 is finished, as shown in FIG. 11 (B), the panel lifter 82 is raised, and the liquid crystal panel 36 is attached to the adsorption surface of the downward suction pad 72. Touch The suction pad 72 vacuum-adsorbs the first surface (surface finished surface) of the liquid crystal panel 36. Thereafter, as shown in Fig. 11C, the panel lifter 82 is lowered, and the inversion arm 70 then rotates clockwise by 180 degrees around its axis. By this rotation, the downward suction pad 72 faces upward while holding the liquid crystal panel 36 by suction. In the liquid crystal panel 36, the second surface (the surface opposite to the first surface) faces upward. Subsequently, as shown in FIG. 11D, the panel lifter 82 is raised, and the inspection table 86 on the upper side thereof contacts the first surface of the liquid crystal panel 36. If the panel lifter 82 is raised further, the liquid crystal panel 36 shifts 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 exits the suction pad 72 and the inversion arm 70, the panel lifter 82 does not collide with the suction pad 72 and the arm 79. . When the liquid crystal panel 36 is moved to the panel lifter 82, the adsorption inversion mechanism returns to the retracted position shown in Fig. 9A. Thus, the panel lifter 82 descends, and the inverted liquid crystal panel 36 returns to the inspection position of Fig. 11A. Then, the external appearance inspection of the 2nd surface of the liquid crystal panel 36 is performed. The panel lifter 82 corresponds to the panel lifting device in the present invention.

After the external inspection of the second surface is finished, the liquid crystal panel 36 is inverted again in the order of FIGS. 11A to 11C, and the first surface faces upward. Thereafter, as shown in FIG. 18, the liquid crystal panel 36 supported by the upward suction pad 72 is received by the downward suction pad 34 of the transfer arm 32. The inspected liquid crystal panel 36 is returned to the cassette stage portion.

Subsequently, the imaging system and the illumination system of the inspection unit will be described. Returning to Fig. 7, the lower structure of the inspection unit is provided with a backlight device 84 (see Fig. 10) of the three kinds of lighting devices. The upper structure of the inspection unit is provided with a coaxial illumination device 88 and a four-beam illumination device 90 of the three types of illumination devices. The lighting box 92 has a rectangular cylindrical shape in its horizontal section, and the upper and lower ends thereof are open. The coaxial illuminator 88, the shutter 94, and the half miller 96 are arrange | positioned inside the lighting box 92. As shown in FIG. In the vicinity of the lower end of the lighting box 92, the illuminating lighting device 90 is fixed. An imaging device 98 is disposed above the lighting box 92. The imaging device 98 is a CCD camera and is equipped with a focus adjustment mechanism. By inserting the image of the imaging device 98 into an image processing apparatus (tester), the image is used for defect determination of the liquid crystal panel. The imaging direction (up-down direction) of the imaging device 98 is parallel to the normal line (this also extends in the up-down direction) of the surface of the liquid crystal panel 36.

Fig. 13 is a perspective view showing the coaxial illuminator 88 and the shutter 94. Figs. Fig. 13A shows the shutter 94 closed, and Fig. 13B shows the shutter 94 open. In Fig. 13A, the coaxial illuminating 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). By opening and closing the shutter 94 up and down by a cylinder (not shown), the shutter 94 is opened and closed.

Fig. 12 is a perspective view showing the structure on the work table 78 and the four-beam illuminating device 90 in the inspection part. Four reflection 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. Four reflective mirrors 62 are provided corresponding to four sides of the rectangular liquid crystal panel 36. The upper part of the panel lifter 82 protrudes from the through-hole in the center of the diffuser plate 80, and the two adsorption holes 87 are formed in the inspection stand 86 of the upper surface. Moreover, the notch 83 of the upper part of the panel lifter 82 is also shown. The liquid crystal panel 36 is held by the suction hole 87. 12 shows a state where the liquid crystal panel 36 is held at the inspection position.

In the vicinity of the lower end of the lighting box 92, the illuminating lighting device 90 is fixed. The light illuminating device 90 is equipped with the light emitting lamp 104 made from four LED (light emitting diode). These light projection lamps 104 are provided corresponding to four sides of the liquid crystal panel 36, and the surface of the liquid crystal panel 36 is projected from four inclined directions.

14 is a side cross-sectional view of the inspection unit, and a cross-sectional view taken along line B-B in FIG. In addition, the adsorption inversion mechanism is omitted. 14 shows a situation in which the liquid crystal panel 36 is observed using only the illumination light by the coaxial illuminator 88. As shown in FIG. The shutter 94 is open and part of the light 106 emitted from the coaxial illuminator 88 is reflected downward from the half miller 96 and directed downward. The half miller 96 is inclined at an angle of 45 degrees with respect to the horizontal plane. Light reflected near the center of the half miller 96 reaches the surface of the liquid crystal panel 36 to illuminate the surface of the liquid crystal panel 36. The light reflected from the four sides of the square half mirror 96 is directed to the four reflection mirrors 62 and is reflected thereon to illuminate the four sides of the liquid crystal panel 36.

Light emitted from the surface of the liquid crystal panel 36 (which is reflected by the illumination light on the surface of the panel and becomes image light on the surface) is directed upward, and a part of the light passes through the half mirror 96 to capture an image. The device 98 is reached. The light emitted from the four sides of the liquid crystal panel 36 (this is the sum of the illumination light reflected from the side of the panel and the illumination light transmitted in the direction of the opposite side, and becomes the image light on the side) is reflected. Reflected by the mirror 62, the upper part of the mirror 62 passes through the half mirror 96 and reaches the imaging device 98. In this manner, the surface image and the four side images of the liquid crystal panel 36 projected by the illumination light by the coaxial illuminator 88 are captured by the imaging device 98. The direction in which the illumination light from the coaxial illuminating 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. have. Therefore, such illumination light is called coaxial lighting, and the lighting device for him is called a coaxial lighting device.

Fig. 16 shows the appearance of the image obtained by the imaging device. There is an image 108 of the surface of the liquid crystal panel in the center, and an image 110 of the four sides of the liquid crystal panel to surround it. The side image 110 is photographed by the imaging device after reflecting from the reflection mirror.

FIG. 15 is a side sectional view showing another illumination state of the inspection unit shown in FIG. This figure shows the situation where the liquid crystal panel 36 is observed using only the illumination light by the four-beam illuminating device 90. Since the coaxial illuminator 88 is in the lit state but the shutter 94 is closed, the coaxial illuminating light does not touch the liquid crystal panel 36. If the coaxial illuminator 88 is turned off when the coaxial illuminator is not used, the shutter 94 is not necessary. In reality, the coaxial illuminator 88 is turned on and off by opening and closing the shutter 94 while the coaxial illuminator 88 is turned on. Switching off. This is because the coaxial illuminating device 88 is composed of a fluorescent tube, and it takes time until the luminance is stable.

From the four projection lamps 104 of the projection lighting apparatus 90, the illumination light (from four inclination 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)) 112). Four directions correspond to four sides of the liquid crystal panel 36. The normal of the surface of the projection lamp 104 inclines with respect to the normal of the surface of the liquid crystal panel 36 in the range of 30-60 degree | times. When the projection lighting apparatus 90 is used, since light hits the liquid crystal panel 36 from a direction different from that of the coaxial illumination, an image such as a wound present in the liquid crystal panel 36 is different from that of the coaxial illumination. It is taken as an image. Also in this case, an image as shown in Fig. 16 is obtained by the imaging device 98.

In Fig. 15, there is a method of using the 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 light illuminating device 90 is turned off. The illumination light by the backlight device 84 passes through the diffuser plate 80 while passing through the diffuser plate 80 to become homogeneous light, which illuminates the rear surface of the liquid crystal panel 36. Light transmitted through the liquid crystal panel 36 is captured by the imaging device 98. When the backlight device 84 is used, scratches and the like inside the liquid crystal panel 36 become clear. In addition, the diffusion 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 is turned on only when necessary.

The six lighting fixtures of the above-mentioned coaxial illuminator 88, the four projection lamps 104, and the backlight unit 84 can be turned on and off independently of each other (however, the coaxial illuminator 88 has a shutter. By combining the lighting and off states of these lighting fixtures, the defects of the liquid crystal panel can be clearly displayed under various lighting conditions. Thereby, the determination reliability of the appearance defect by automatic test | inspection becomes high. As items to be found in this visual inspection, for example, defects in glass (e.g., cracks, omissions, etc.), defects in polarizing plates (e.g., flipped), defects in liquid crystal encapsulant, electrode portions Defects, defects in the protective sheet, and the like.

17 is an enlarged view of a part of an image example of an imaging device. If there is a wound on the glass plate of the liquid crystal panel and the wound extends to the inside of the glass plate, an image of the wound as shown in Fig. 17 is taken. The image 108 of the panel surface can determine the size of the wound 112. In the right side image 110a and the edge side image 110b, the depth of the wound d can be determined.

In the above-described embodiment, the liquid crystal panel is shown as being square, but may be rectangular. In the case of a rectangular liquid crystal panel, it is preferable to change the length of the reflection mirror 62 and the projection lamp 104 according to the length of the short side or long side of the liquid crystal panel 36, for example.

Since the present invention is equipped with a coaxial illuminating device, a glare illuminating device and a backlight device, the liquid crystal panel can be irradiated with illumination light under various lighting conditions, so that scratches and dust on the liquid crystal panel can be reliably photographed. Moreover, since this invention can convey a liquid crystal panel by a pre-alignment apparatus by a test | inspection apparatus using a conveyance apparatus, and can also reverse the liquid crystal panel in an inspection position using the inversion apparatus independent of a conveying apparatus, The liquid crystal panel of the present invention can be automatically inspected on both sides thereof, and furthermore, it has the effect of the invention that the next liquid crystal panel can be brought to the prealignment device by using the transfer device between the inverting operations of the liquid crystal panel.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (5)

A prealignment device for positioning the rectangular liquid crystal panel before inspection; An inspection table for supporting the liquid crystal panel at an inspection position; A conveying apparatus for conveying the liquid crystal panel according to the inspection section in the prealignment apparatus; An imaging device which picks up the liquid crystal panel at the inspection position from a direction parallel to the normal of the liquid crystal panel; A coaxial illumination device for irradiating light to the liquid crystal panel at the inspection position from a direction substantially parallel to the imaging direction of the imaging device; A projection lighting apparatus for irradiating light to the liquid crystal panel at the inspection position from four directions corresponding to four sides of the liquid crystal panel as four directions inclined with respect to the imaging direction; A backlight device for irradiating light from a rear surface of the liquid crystal panel at the inspection position; Four reflection mirrors disposed to face four sides of the liquid crystal panel at the inspection position, the reflection mirrors reflecting light from the side toward the imaging device; And An inverting device capable of receiving the liquid crystal panel above the inspection position and inverting the liquid crystal panel, the inverting device independent of the conveying device; Appearance inspection apparatus of the liquid crystal panel, characterized in that consisting of. The liquid crystal panel of claim 1, wherein the liquid crystal panel is horizontally supported at the inspection position. The inverting device may include: an adsorption pad capable of adsorbing the liquid crystal panel in a horizontal state above the inspection position to a downward adsorption surface; A rotating device for rotating the suction pad around a horizontal axis of rotation so that the suction surface faces upward; And The liquid crystal panel at the inspection position can be raised downward to the adsorption surface, and the liquid crystal panel can be received without interfering with the adsorption pad from the adsorption pad in a state where the liquid crystal panel is adsorbed onto the adsorption surface upward. A panel elevating device capable of lowering the liquid crystal panel to the inspection position; Appearance inspection apparatus of the liquid crystal panel, characterized in that consisting of. 3. The panel elevating device has an elevating adsorption surface on which an adsorption hole for adsorbing and holding the liquid crystal panel is opened, and the elevating adsorption surface has a flaw not to interfere with the adsorption pad. Appearance inspection device of the liquid crystal panel. 2. The apparatus for inspecting the appearance of a liquid crystal panel according to claim 1, wherein the conveying apparatus includes a plurality of adsorption pads capable of adsorbing and holding two liquid crystal panels separately. The apparatus of claim 1, wherein the inverting device includes a panel elevating device for elevating the liquid crystal panel, and the backlight device includes an annular light source surrounding the panel elevating device.

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