JP2001206542A - Panel reversing mechanism and panel reversing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a panel reversing mechanism and a panel reversing method capable of reversing even a large panel in a stable state by extremely reducing a change of a gap between substrates at the time of reversing the panel. SOLUTION: This panel reversing mechanism can properly avoid extension of a gap between substrates and reverse even a heavy and large panel in a stable state as it clamps the panel having the gap between the substrates by a flat plate type upper hand 10 and a flat plate type lower hand 11 arranged in parallel with each other and comes to freely and uniformly clamp both flat surfaces of the panel 2. Consequently, it is possible to reverse the small panel to the large panel, to perform the reversing mechanism extremely high in generality and to properly prevent quality deterioration of the panel 2 caused at the time of reversing the panel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a panel reversing mechanism and a panel reversing method used for reversing a panel (for example, a liquid crystal panel or a plasma display panel) having a gap between a pair of substrates.

[0002]

2. Description of the Related Art Conventionally, as a technique in such a field, there is Japanese Patent Application Laid-Open No. H11-157628. Have been. As another reversing mechanism, there is JP-A-8-114790. The panel reversing mechanism described in this publication has one side of the liquid crystal panel in a state where both edges of the liquid crystal panel are clamped by a clamp mechanism. It is configured to achieve inversion such that the center is at the center.

[0003]

However, the above-mentioned conventional panel reversing mechanism has the following problems. That is, in the former case, as shown in FIG.
When the front substrate 101 is sucked by the suction pad 102 and the liquid crystal panel 100 is lifted by the suction pad 102, the liquid crystal panel 100 is suspended only by the front substrate 101, and due to the weight of the panel 100 itself,
The gap G between the front substrate 101 and the back substrate 103 is widened. As a result, the display quality of the liquid crystal panel is degraded (for example, display color unevenness and luminance unevenness), and such a problem is particularly noticeable in a heavy liquid crystal panel of 15 inches or more. there were. In the latter case, since the panel is inverted by clamping only both edges of the panel, when the panel is enlarged, the gap G between the front substrate 101 and the rear substrate 103 is reduced when the panel is inverted. There is a possibility that the liquid crystal panel 100 spreads greatly at the center portion, and there is a problem that the quality of the panel is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. In particular, the change in the gap between the substrates when the panel is inverted is extremely small, and even a large panel can be inverted in a stable state. It is an object of the present invention to provide a panel reversing mechanism and a panel reversing method.

[0005]

According to a first aspect of the present invention, there is provided a panel inverting mechanism for inverting a panel having a gap between a pair of substrates, wherein the panel is brought into contact with the surface of one of the upper substrates. A flat upper hand, a flat lower hand placed parallel to the upper hand and abutting against the surface of the other substrate located on the lower side, and the upper hand and the lower hand in the vertical direction. A drive means for moving the upper hand and the lower hand at the same time while moving the panel relatively up and down and sandwiching the panel is provided.

In this panel reversing mechanism, a panel having a gap between substrates is sandwiched between a flat upper hand and a flat lower hand arranged in parallel with each other. It is possible to sandwich both planes of the panel evenly, and as a result, it is possible to appropriately prevent the spread of the gap between the substrates,
Even a heavy large panel can be inverted in a stable state. Therefore, it is possible to invert from a small panel to a large panel, an extremely versatile inversion mechanism is achieved, and it is possible to appropriately prevent the deterioration of the panel quality that occurs at the time of inversion.

In the panel reversing mechanism according to claim 2,
The apparatus further includes a holder having a claw for holding an edge portion of the panel inserted between the upper hand and the lower hand from below.
When such a configuration is employed, the panel can be appropriately supported between the upper hand and the lower hand, and when the lower hand is raised, the panel can be easily received from the claw to the lower hand. Can be passed.

[0008] In the panel reversing mechanism according to claim 3,
At least one of the upper hand and the lower hand is provided with a stopper that abuts the side surface of the panel that has caused a lateral shift in the width direction when the panel is rotated between the upper hand and the lower hand. When such a configuration is adopted, the panel may fall from between the upper hand and the lower hand even if the panel is laterally displaced in the width direction due to insufficient sandwiching force between the upper hand and the lower hand. Can be appropriately prevented by the stopper.

In the panel reversing mechanism according to claim 4,
The stopper includes a contact portion protruding from the inner surface of the upper hand and a leaf spring having a contact portion at one end and the other end fixed to the upper hand. When such a configuration is adopted, the stopper provided on the upper hand has an elastic force due to the adoption of the leaf spring. As a result, even when the contact portion is pushed in on the surface of the panel, the contact portion is kept on the panel. The stopper contributes to preventing the panel from slipping because it continues to resiliently contact the surface of the panel.

[0010] In the panel reversing mechanism according to claim 5,
The stoppers are arranged side by side in the width direction of the upper hand. When such a configuration is adopted, the stoppers provided on the upper hand are arranged side by side in the width direction, so that it is possible to correspond to panels of various widths.

[0011] In the panel reversing mechanism according to claim 6,
The stopper includes a contact portion protruding from the inner surface of the lower hand, and a leaf spring having a contact portion at one end and the other end fixed to the lower hand. When such a configuration is adopted, the stopper provided on the lower hand has an elastic force due to the use of a leaf spring. As a result, even if the contact portion is pushed in on the surface of the panel, the contact portion is kept on the panel. The stopper contributes to preventing the panel from slipping because it continues to resiliently contact the surface of the panel.

[0012] In the panel reversing mechanism according to claim 7,
The stoppers are arranged side by side in the width direction of the lower hand. When such a configuration is adopted, the stoppers provided on the lower hand are arranged side by side in the width direction, so that it is possible to correspond to panels of various widths.

According to an eighth aspect of the present invention, in the method of inverting a panel having a gap between a pair of substrates, a horizontally disposed flat upper hand and a flat lower hand are arranged in parallel. In a state where the panel is separated from the upper hand and the lower hand, a step of holding an edge portion of the inserted panel from below with a claw, and holding the panel with a claw. Raising the lower hand in the vertical direction in the state, lifting the panel so as to separate from the claw portion, and sandwiching the panel with the upper hand and the lower hand,
While the panel is sandwiched between the upper hand and the lower hand, the upper hand and the lower hand are simultaneously rotated to rotate the panel, and after the flip, the upper hand located on the lower side is lowered in the vertical direction, Holding the edge portion from below with the claw portion.

In this panel inversion method, a panel having a gap between substrates is inverted so as to be sandwiched between a flat upper hand and a flat lower hand arranged in parallel with each other. Can be reliably supported, and as a result, the expansion of the gap between the substrates can be appropriately prevented, and even a large panel can be inverted in a stable state.
In addition, since the panel is appropriately held by the claw between the upper hand and the lower hand, when the lower hand is raised, the panel is transferred from the claw to the lower hand. Then, by lowering the upper hand located on the lower side after the inversion, the edge of the panel is placed again on the claw portion, and the panel after the inversion is moved from between the upper hand and the lower hand by a robot arm or the like. You are ready to be removed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a panel reversing mechanism according to the present invention will be described below in detail with reference to the drawings.

Panel reversing mechanism 1 shown in FIGS. 1 and 2
Is used for reversing a panel 2 having a gap between a pair of substrates, such as a liquid crystal panel or a plasma display panel which has been increasing in size in recent years. As shown in FIG. 3, a liquid crystal panel as an example of the panel 2 includes:
A gap G is formed between the back glass substrate 3 on which the circuit wiring 5 is formed and the front glass substrate 4 on which the color filter 6 is formed. The gap G is filled with a liquid crystal, and the spacers 7 are uniformly dispersed and arranged. The periphery of the panel 2 is sealed with a sealant 8 to form a sealed gap G. . It is preferable that the dimension of the gap G is widened or narrowed in the panel manufacturing stage or the inspection stage, because it causes a decrease in display quality of the liquid crystal panel 2 (for example, display color unevenness and brightness unevenness). is not. Such a gap G affects the quality of the panel 2 even in a change of a submicron unit. Therefore, the panel reversing mechanism 1 has been proposed for the purpose of avoiding such a situation when the panel is reversed.

As shown in FIGS. 1 and 2, a panel reversing mechanism 1 is a flat upper hand 1 for holding a panel 2 therebetween.
0 and a flat lower hand 11. Each hand 1
Numerals 0 and 11 are configured to be independently moved up and down and rotated by the driving means 12. That is, the upper hand 10 is capable of independent vertical movement.
The lower hand 11 is likewise attached to the second lifting / lowering means 15 via the lifting / lowering means 13 of FIG.
And is attached to a rotating plate (rotating means) 14 through. The rotating plate 14 as a rotating means is arranged so as to rotate in a vertical plane by a motor M of a driving shaft 9 fixed at the center thereof. Inversion can be performed with a minimum radius of rotation, and the space for inversion of the panel 2 can be minimized.

Further, the first lifting / lowering means 13 includes a rotating plate 14
And a slider 17 that moves up and down along a guide rail 16 that extends in the vertical direction.
The upper hand 10 is fixed to 7. In order to drive the slider 17, a ball screw shaft 18 driven by a motor is fixed to the rotating plate 14.
, A female screw portion 19 to be screwed with the ball screw shaft 18 is fixed. Therefore, by rotating the ball screw shaft 18 by the motor 20, the slider 17 can be moved up and down as needed. Also, the first lifting / lowering means 1
3 is attached to the rotating plate 14 that rotates in a vertical plane, and thus rotates integrally with the rotating plate 14.

Similarly, the second lifting / lowering means 15 is provided with the rotating plate 1.
4 has a slider 22 that moves up and down along a guide rail 21 extending in parallel with the above-mentioned guide rail 16. The lower hand 11 is fixed to this slider 22. Then, in order to drive this slider 22,
A ball screw shaft 23 driven by a motor is fixed to the rotating plate 14 so as to extend in parallel with the ball screw shaft 18, and a female screw portion 24 screwed to the ball screw shaft 23 is fixed to the slider 22. . Therefore, by rotating the ball screw shaft 23 by the motor 25, the slider 22 can be moved up and down as necessary.

Thus, the first and second lifting means 1
Since the members 3 and 15 are respectively attached to the rotating plate 14 that rotates in a vertical plane, the rotating members 14 and 15 can be rotated integrally with the rotating plate 14 and can be independently raised and lowered as necessary. As a result, the panel 2 is moved to the upper hand 10 and the lower hand 11.
And the first and second elevating means 13,
When the panel 15 is used and the panel 2 is rotated with the panel 2 sandwiched therebetween, the rotating plate 14 is used and the hands 10 and 1 are used.
1 enables independent lifting and lowering and rotation.

Here, the upper hand 10 and the lower hand 11 used in the panel reversing mechanism 1 are formed in a flat plate shape in order to appropriately perform a sandwiching rotation so as to hold the gap G inside the panel 2. Panel 2 is uniformly sandwiched. Specifically, as shown in FIGS. 4 and 5, the upper hand 10 is attached to the rotating plate 14 so as to extend in a horizontal direction in a cantilevered state. Further, a plurality of resin pressing portions 26 pressed against one surface of the panel 2 are fixed to the upper hand 10, and each pressing portion 26 is aligned in two rows at the center along the surface of the upper hand 10. ing. Further, a spring 27 is incorporated in each pressing portion 26 (see FIG. 6), and by using this spring 27, each pressing portion 26 is pressed against the panel 2 with an appropriate force, thereby contributing to preventing lateral displacement when the panel is inverted. I do.

Similarly, the lower hand 11 is parallel to the upper hand 10 so as to extend horizontally in a cantilevered state with respect to the rotating plate 14 as shown in FIGS. Installed. Further, the lower hand 11 has a plurality of resin pressing portions 2 pressed against one surface of the panel 2.
8 are fixed, and each pressing portion 28 is aligned in two rows at the center along the surface of the lower hand 11 at a position facing the pressing portion 26 of the upper hand 10. In addition, each pressing portion 28
Has a built-in spring 29 (see FIG. 6), and by using this spring 29, each pressing portion 26 is pressed against the panel 2 with an appropriate force, thereby contributing to preventing lateral displacement when the panel is inverted. The panel 2 at the time of reversing is reliably sandwiched at the center by the cooperation of the upper pressing section 26 and the lower pressing section 28 provided so as to face each other at the center. Can be reduced, and lateral displacement can be reliably prevented.

Further, as shown in FIGS. 5 and 8, the upper hand 10 includes a panel 2 with an upper hand 10 and a lower hand 11.
A stopper 30 is provided to prevent the panel 2 from dropping due to lateral displacement in the width direction when the panel 2 is sandwiched and rotated. The stopper 30 has a cylindrical resin contact portion 3 protruding from the inner surface 10 a of the upper hand 10.
1 and a leaf spring 32 having one end provided with a contact portion 31 and the other end fixed to the upper hand 10. The stopper 30 is fixed to the peripheral edge of the upper hand 10 in a cantilevered state, and the abutting portion 31 projects so as to close a gap when the panel 2 is sandwiched between the upper hand 10 and the lower hand 11. .
Therefore, when the panel 2 is displaced laterally, the side surface 2a (see FIG. 10) of the panel 2 hits the contact portion 31, so that the panel 2 is properly prevented from dropping during inversion.

Further, the side of the stopper 30 (the upper hand 10
Upper hand 1 to enable position adjustment in the
0, a slit groove 33 extending laterally is formed, and the leaf spring 32 is provided with the adjusting screw 3 inserted into the slit groove 33.
5 fixes the upper hand 10. In addition, the stopper 30 is extended along the direction in which the slit groove 33 extends.
Are arranged side by side, and correspond to panels 2 of various widths to be sandwiched between the upper hand 10 and the lower hand 11.

Similarly, as shown in FIGS. 7 and 8, the lower hand 11 is also provided with a stopper 34.
4 has a cylindrical resin contact portion 36 protruding from the inner surface 11a of the lower hand 11, and a leaf spring 37 provided with the contact portion 36 at one end and the other end fixed to the lower hand 11. ing. The stopper 34 is fixed to the lower hand 11 in a cantilevered state, and the contact portion 36 protrudes so as to close a gap when the upper hand 10 and the lower hand 11 sandwich the panel 2.

Then, as a result of positioning the contact portion 36 outside the contact portion 31, the panel 2 which has caused lateral displacement
Can be reliably prevented from cooperating with the contact portion 31. As shown in FIG. 9, when the large-sized panel 2 is sandwiched by the cooperation of the inner contact portion 31 and the outer contact portion 36, the contact portions 31 and 3 are formed by the surface of the panel 2.
6, the contact portions 31 and 36 continue to resiliently contact the surface of the panel 2, and the contact portions 31 and 3
6, the lateral displacement of the panel 2 can be appropriately prevented.

Further, beside the stopper 34 (the lower hand 11)
Lower hand 1 to enable position adjustment in the width direction of
1 is formed with a slit groove 38 extending laterally, and the leaf spring 37 is provided with the adjusting screw 3 inserted into the slit groove 38.
9 is fixed to the lower hand 11. Further, stoppers 34 are arranged along the slit grooves 38 so as to correspond to panels 2 of various widths to be sandwiched between the upper hand 10 and the lower hand 11.

Therefore, as shown in FIG.
When stoppers 40A, 40B, 40C having the same configuration as described above are provided on the left and right sides of the lower hand 11 and the lower hand 11,
For the smallest panel 2A, the innermost left and right stoppers 40A are used to prevent the panel 2A from dropping during inversion. As shown in FIG. 11, a middle stopper 40B is used for the middle-sized panel 2B.
A is in a state pressed against the surface of panel 2B. Further, as shown in FIG. 12, the outermost stopper 40C is used for the largest panel 2C. At this time, the stoppers 40A and 40B located inside the stopper 40C are connected to the surface of the panel 2C. Is pressed. Thus, the stoppers 40A, 40B, 40C
Are arranged side by side in the width direction of the upper hand 10 and the lower hand 11, thereby making it possible to correspond to at least three types of panels 2.

Further, the panel reversing mechanism 1 uses an upper hand 10 and a lower hand 11 using a robot arm (not shown).
And a pair of left and right holders 42 for holding the panel 2 inserted between the two in a horizontal state. As shown in FIG. 13, the holder 42 has a pole-shaped arm 44 suspended from a top plate 43.
At the lower end, a claw portion 45 that projects horizontally toward the inside is provided. Then, in order to maintain the panel 2 in a horizontal state, the panel 2 is held by the six claw portions 45 arranged in a horizontal plane. Note that the left and right holders 42 can be adjusted to move in the width direction so as to correspond to panels 2 having various widths.

In order to properly hold the panel 2 between the upper hand 10 and the lower hand 11, as shown in FIGS. 5 and 7, cuts 46 at the edges of the upper hand 10 and the lower hand 11 are formed. The claws 45 are arranged. Such a claw part 45
The panel 45 is properly transferred from the claw 45 to the lower hand 11 when the lower hand 11 is raised when the upper hand 10 and the lower hand 11 are raised and lowered. It becomes possible.

Next, a method of inverting the liquid crystal panel 2 by the panel inversion mechanism 1 having the above-described configuration will be described.
In this case, in the pixel correction process scheduled in the next process, it is necessary to irradiate the corrected pixel with a laser beam from above, so that the glass substrate 3 on the back side needs to be directed upward. 2 is inverted.

First, the liquid crystal panel 2 produced in a normal line is transported using the robot arm H, and the front glass substrate 4 on which the color filters 6 are formed (see FIG. 3).
Is inserted into the panel reversing mechanism 1 while maintaining the horizontal state. At this time, as shown in FIG.
An edge portion of the panel 2 is supported from below by a claw portion 45 disposed between the upper hand 10 and the lower hand 11, and as a result, the panel 2 is held in a horizontal state.

After that, as shown in FIG. 15, the lower hand 11 is raised by driving the second lifting / lowering means 15 (see FIG. 1). It is delivered to the lower hand 11 from 45.
Then, as shown in FIG. 16, when the lower hand 11 is further raised, the panel 2 is sandwiched between the upper hand 10 and the lower hand 11 waiting upward with an appropriate clamping force.

In this state, as shown in FIG. 17, the rotating plate 14 is rotated by 180 degrees in the direction of the arrow by driving the motor M (see FIG. 2), and the panel 2 is sandwiched between the upper hand 10 and the lower hand 11. The panel 2 is inverted on the spot while maintaining the state. Thereafter, as shown in FIG. 18, the first lifting / lowering means 13 (see FIG. 1) is operated to lower the upper hand 10 which has been lowered after the inversion. At this time, panel 2
Continues to descend while being placed on the upper hand 10, during this descending, the panel 2 is transferred from the upper hand 10 to the claw 45, and the panel 2 is supported by the claw 45 from below. .

Then, as shown in FIG.
When 0 is further lowered, the inverted panel 2 is maintained in a suspended state supported by the claw portions 45. Then, the robot arm H is inserted under the panel 2 so that the panel 2 is lifted by the robot arm H. In this state, the panel 2 is carried out of the panel reversing mechanism 1 together with the robot arm H. Thereafter, the panel 2 is sent into a pixel correcting device (not shown) by the robot arm H, and the corrected pixel is irradiated with a laser beam from above with the glass substrate 3 on the back side facing upward, so that the panel 2 is repaired. Will be executed. Note that specific repair processing of a liquid crystal panel is disclosed in JP-A-9-90304, and specific repair processing of a plasma display panel is disclosed in JP-A-10-162742.

The panel reversing mechanism and the panel reversing method of the present invention are not limited to being used for reversing the above-mentioned liquid crystal panel. And is most suitable for the panel 2 in which a change in the gap G at the time of inversion affects the quality.

[0037]

Since the panel reversing mechanism according to the present invention is constructed as described above, the following effects can be obtained. That is, in a mechanism for inverting a panel having a gap between a pair of substrates, a flat upper hand to be brought into contact with the surface of one of the upper substrates, and a lower hand arranged in parallel with the upper hand. The lower hand in a flat plate shape to be brought into contact with the surface of the other substrate located on the side, and the upper hand and the lower hand are vertically moved relatively up and down, and the upper hand and the lower hand are moved in the direction to flip the panel. With the provision of the driving means for rotating simultaneously, the change in the gap between the substrates at the time of panel inversion is extremely reduced, and even a large panel can be inverted in a stable state.

Similarly, in a method of inverting a panel having a gap between a pair of substrates, a horizontally arranged flat upper hand and a flat lower hand are separated from each other in parallel with the upper hand. A step of inserting the panel between the lower hand and a step of holding the edge of the inserted panel from below with a claw; and raising the lower hand in a vertical direction while holding the panel with the claw. Lifting the panel so as to separate it from the claw, holding the panel between the upper hand and the lower hand, and simultaneously rotating the upper hand and the lower hand while holding the panel between the upper hand and the lower hand. The method includes a step of inverting the panel, and a step of holding the edge of the panel from below with the claws while vertically lowering the upper hand located on the lower side after the inversion. Of very small changes in the gap it can be reversed in a stable state even in a large panel.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a panel reversing mechanism according to the present invention.

FIG. 2 is a plan view of the panel reversing mechanism shown in FIG.

FIG. 3 is a sectional view showing a liquid crystal panel applied to the panel reversing mechanism.

FIG. 4 is a perspective view showing an upper hand and a lower hand.

FIG. 5 is a plan view showing the upper hand.

FIG. 6 is a sectional view showing a pressing unit applied to the upper hand and the lower hand.

FIG. 7 is a plan view showing a lower hand.

FIG. 8 is a cross-sectional view showing a state where upper and lower stoppers are closed.

FIG. 9 is a sectional view showing a state where upper and lower stoppers are opened.

FIG. 10 is a front view showing a relationship between a panel having a minimum dimension and a stopper.

FIG. 11 is a front view showing a relationship between a middle panel and a stopper.

FIG. 12 is a front view showing a relationship between a panel having a maximum size and a stopper.

FIG. 13 is a perspective view showing a holder applied to the panel reversing mechanism.

FIG. 14 is a front view showing a state where a panel is arranged between an upper hand and a lower hand.

FIG. 15 is a front view showing a state where the lower hand is raised and a panel is delivered to the lower hand.

FIG. 16 is a front view showing a state where the lower hand is further raised and a panel is sandwiched between the upper hand and the lower hand.

FIG. 17 is a front view showing a state where the panel sandwiched between the upper hand and the lower hand is in the process of being inverted.

FIG. 18 is a front view showing a state in which the upper hand is lowered in order to transfer the inverted panel to the holder.

FIG. 19 is a front view showing a state where the panel is delivered to the holder.

FIG. 20 is a cross-sectional view showing a state in which a liquid crystal panel is lifted up by a suction pad at the time of inversion and a gap is opened in the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Panel reversing mechanism, 2 ... Panel, 2a ... Side of panel, 3 ... 4 Glass substrate (substrate), 10 ... Upper hand, 1
1 lower hand, 12 driving means, 30, 34, 40A,
40B, 40C: stopper, 31, 36: contact part, 3
2, 37: leaf spring, 42: holder, 45: claw, G:
gap.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koji Kuno 1-126, Nomachi, Hamamatsu-shi, Shizuoka Prefecture F-term within Hamamatsu Photonics Co., Ltd. NS17 3F061 AA01 BB08 BC01 BD04 BE23 BE43 BE47 DB00 DB04 DB06 5F031 CA05 GA16

Claims (8)

[Claims] 1. A mechanism for inverting a panel having a gap between a pair of substrates, comprising: a flat upper hand contacting a surface of one of the upper substrates; And a flat lower hand contacting the surface of the other substrate located on the lower side, and vertically moving the upper hand and the lower hand relatively vertically and sandwiching the panel A panel reversing mechanism, comprising: driving means for simultaneously rotating the upper hand and the lower hand in a slid state. 2. The panel according to claim 1, further comprising a holder having a claw portion for holding an edge portion of the panel inserted between the upper hand and the lower hand from below. Reversing mechanism. 3. A side surface of the panel that causes a lateral displacement in a width direction when the panel is sandwiched and rotated between the upper hand and the lower hand on at least one of the upper hand and the lower hand. 3. The panel reversing mechanism according to claim 1, wherein a stopper is provided to abut the panel. 4. The stopper comprises: a contact portion protruding from an inner surface of the upper hand; and a leaf spring having the contact portion at one end and the other end fixed to the upper hand. The panel reversing mechanism according to claim 3, wherein 5. The panel reversing mechanism according to claim 3, wherein said stoppers are arranged in parallel in a width direction of said upper hand. 6. The stopper comprises a contact portion protruding from the inner surface of the lower hand, and a leaf spring having the contact portion at one end and the other end fixed to the lower hand. The panel reversing mechanism according to any one of claims 3 to 5. 7. The panel reversing mechanism according to claim 3, wherein said stoppers are arranged side by side in a width direction of said lower hand. 8. A method of inverting a panel having a gap between a pair of substrates, wherein the upper hand and the lower flat hand which are horizontally arranged are separated from each other in parallel. A step of inserting the panel between the lower hand and the lower hand; a step of holding an edge portion of the inserted panel from below with a claw; and the lower hand with the panel held by the claw. Raising the panel vertically so as to separate the panel from the claw portion; holding the panel between the upper hand and the lower hand; and holding the panel between the upper hand and the lower hand. In this state, simultaneously rotating the upper hand and the lower hand to invert the panel; and, after inversion, lowering the upper hand located on the lower side in the vertical direction, Holding the edge portion of the panel from below with the claw portion.