JP3980295B2 - Work transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work carrier in which the static charged state of a larger number of works can be detected efficiently and accurately using a small number of measuring instruments without limiting the object of measurement directly to a work, e.g. a liquid crystal substrate. SOLUTION: The liquid crystal substrate carrier 2 for receiving a liquid crystal substrate 1 and transferring it to an other place comprises an arm 3 for mounting and holding the liquid crystal substrate, and means 4, 6, 11 and 13 for detecting charged state of the liquid crystal substrate by measuring at least either one of the quantity of charges or the potential being induced on the arm 3.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a workpiece transfer device having means for measuring the charged state of (a) a workpiece, (b) a device on which the workpiece is placed, or (c) a device that transfers the workpiece, and more specifically, (a) The present invention relates to a liquid crystal substrate, (b) an apparatus on which the liquid crystal substrate is placed, or (c) an apparatus for transporting the liquid crystal substrate.
[0002]
[Prior art]
An example shown in FIG. 13 is disclosed as a substrate transfer device for a liquid crystal display device (Japanese Patent Laid-Open No. 6225563/1990). In order to measure the charge amount of the liquid crystal substrate 101, a surface potential sensor 111 is installed outside the transfer device, and the substrate is moved when the transfer device holds the liquid crystal substrate on the transfer arm and passes under the surface potential sensor. The surface potential is measured. Similarly, in a cassette or the like for storing a liquid crystal substrate, it is also known to install a surface potential sensor and measure the charged state of the substrate.
[0003]
[Problems to be solved by the invention]
In manufacturing the liquid crystal display device, the following can be exemplified as a portion where the liquid crystal substrate is placed in a stationary state and a device for moving the liquid crystal substrate.
(A) A cassette made of resin or metal for storing a plurality of liquid crystal substrates (b) A positioning unit for positioning the liquid crystal substrate (c) A table (d) for fixing the liquid crystal substrate for processing by a processing device Transport robot (e) roller Recently, there is a tendency that a transport robot is used frequently. In the above-described transport device that measures the surface potential of the liquid crystal substrate, in order to detect the charged state of the substrate, a surface potential sensor is disposed above the substrate surface, and the surface potential of the substrate is directly measured. In order to directly measure the substrate potential, it is necessary to bring the surface potential sensor closer to the substrate surface. However, since there is a possibility that the surface potential sensor at a position close to the substrate surface, such as the substrate delivery position, may interfere with the transfer device, another measurement method is required.
[0004]
Further, in order to measure the charged state of the part where the liquid crystal substrate being transported is placed or the part where the liquid crystal substrate is transported, it is necessary to install a surface potential sensor for each measurement part. Further, when measuring the charged state of a liquid crystal substrate housed like a cassette, a surface potential sensor cannot be attached above the surface of the liquid crystal substrate, so it is necessary to measure from the side surface of the cassette. Due to the measurement from this side, the accuracy of the measurement is reduced. Further, since about 20 liquid crystal substrates are usually stored in a cassette used for the liquid crystal substrate, the height of the cassette is about 300 mm to 1000 mm depending on the size of the liquid crystal substrate. For this reason, in order to measure the potentials of all the liquid crystal substrates, a large number of, for example, ten or more surface potential sensors are required. In a liquid crystal display manufacturing factory, there are many positions where cassettes are placed, and it is difficult to grasp the charged state of the substrate in all of them.
[0005]
Therefore, the present invention provides an apparatus that can efficiently and accurately determine the charged state of a large number of workpieces by installing a small number of measuring devices without directly measuring a workpiece such as a liquid crystal substrate. Objective.
[0006]
[Means for Solving the Problems]
A workpiece transfer device according to the present invention is a workpiece transfer device that receives a workpiece and moves it to another place, and measures the amount of electric charge induced in the arm by loading and holding the workpiece, thereby charging the workpiece. And a workpiece charging state detecting means for detecting the state . Furthermore, based on the correspondence data that takes the correspondence between the charge amount induced in the arm measured by the workpiece charging state detection means and the charging state of at least one of the workpiece and the part where the workpiece is placed, And a workpiece charged state indexing means for determining a charged state of at least one of the portion where the workpiece is placed .
[0007]
With this configuration, the charged state of the workpiece can be known based on a phenomenon such as electrostatic induction generated in the arm without directly measuring the workpiece potential. For this reason, it is not necessary to bring the measuring means close to the work, and the work conveying means and the measuring means do not interfere with each other. Further, it is only necessary to provide the arm measuring means only for the work conveying device at a special point where many work flows are joined, without providing the measuring means for all the work flows in the factory. As a result, it is possible to efficiently grasp the charged state of many workpieces with a small number of measuring means. Furthermore, for example, it is not necessary to forcibly measure the potential of the workpiece placed on the cassette in a narrow place, and it is not necessary to perform measurement with poor accuracy.
[0008]
The material constituting the arm may be a conductor or a composite material of a conductor and an insulator. The workpiece transfer device is a broad concept including a workpiece transfer robot.
[0010]
Since the workpiece potential is not directly measured, a means for calculating the workpiece potential from the amount of charge induced in the arm is required. The means for determining the potential of the workpiece includes correspondence (calibration) data that takes a correspondence with the amount of charge such as electrostatic induction generated in the arm or the potential of the workpiece in advance. Further, the correspondence (calibration) data may be replaced with calculation data simulating the same content instead of the actual measurement data. By comparing the above-mentioned workpiece charging state indexing means with the amount of charge induced in the arm, it becomes possible to know the workpiece or a portion where the workpiece is placed, for example, the charging state in the cassette.
[0011]
The workpiece transfer device of the present invention includes an operation control unit that controls the operation of the arm, and the workpiece charging state indexing unit loads the workpiece and the workpiece according to the stage of the operation of the arm obtained from the operation control unit. The charged state of at least one of the placed portions can be determined (Claim 2 ).
[0012]
In order to determine the charged state of the workpiece from the arm measurement, it is important to know what the environment surrounding the arm is. That is, whether the arm is loaded with a workpiece only, inserted into the cassette and not loaded with a workpiece, loaded with a workpiece in the cassette, loaded with a workpiece, and cassette It is necessary to know whether it has been pulled out from. By the operation control means, the environment of the arm can be easily known, and the charged state of the cassette or the part where the cassette is placed can be distinguished and accurately determined.
[0013]
In the workpiece transfer device of the present invention, the workpiece charging state detection unit can include an electricity quantity measuring unit that measures the amount of electricity flowing between the arm and the ground.
[0014]
Since the arm includes a conductor, charge is induced by electrostatic induction or the like. During this electrostatic induction, a current (charge) flows with the ground. By measuring this current or electric charge, it is possible to know the potential of the arm and further to know the charged state of the workpiece and the workpiece mounting portion.
[0015]
The workpiece transfer apparatus as a reference example of the present invention can include a potential measurement unit in which the workpiece charging state detection unit measures the potential of the arm. By knowing the potential of the arm, it is naturally possible to know the charged state of the workpiece and the workpiece mounting portion.
[0016]
The workpiece transfer device of the present invention can include a warning signal activating means for generating a warning signal when the value of the workpiece charging by the workpiece charging state indexing means exceeds an allowable value (Claim 3 ).
[0017]
This warning signal can be neutralized by an ionizer that disperses the charge opposite to that of the workpiece, and the cause of charging can be detected and removed. Based on these warning signals, naturally, the activation of an ionizer or the like can be automated.
[0018]
The workpiece transfer device of the present invention can include a ground connection means for connecting the workpiece transfer means and the ground wire so that the arm potential becomes zero (claim 4 ).
[0019]
In order to clarify the initial potential of the arm, the arm may be set to zero volts before measuring the potential of the arm or the like. In such a case, the arm can be immediately brought to the ground potential by the ground connection means. As a result, it is possible to improve the measurement accuracy and accurately grasp the charged state of the workpiece.
[0020]
Above the work conveying apparatus of the present invention, the workpiece is a liquid crystal substrate, it is possible the workpiece transfer device is a liquid crystal substrate transfer apparatus (claim 5).
[0021]
With this configuration, it is possible to know the charged state of the liquid crystal substrate by measuring the amount of charge induced on the arm of the transfer robot of the liquid crystal substrate, and to take necessary measures.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0023]
(Embodiment 1)
FIG. 1 is a diagram showing the configuration of the liquid crystal substrate transport device according to Embodiment 1 of the present invention. This liquid crystal substrate transport device is a device that verifies whether or not the charged state of the liquid crystal substrate can be known by measuring the potential of the arm that forms the basis of the present invention and the amount of electric charge flowing between the liquid crystal substrate and the ground. is there. In FIG. 1, the liquid crystal substrate 1 is placed on a cassette 20. In this liquid crystal substrate, a surface potential sensor 11 a is disposed near the surface of the liquid crystal substrate and is connected to the surface potential meter 11. The surface potential sensor 11a is a measuring means for associating with the data about the arm, and may be included in the original transport device of the present invention, but is not essential.
[0024]
In addition, the arm 3 is connected to the ground 5, and a minute ammeter (charge meter) 4 is disposed between them to measure the charge flowing between the arm and the ground. This microammeter corresponds to a measuring means for an arm that measures the amount of electric charge or potential induced in the arm. The surface potential and the charge (current) are recorded over time.
[0025]
2A, 2 </ b> B, and 2 </ b> C, the operation until the arm 3 approaches and the liquid crystal substrate 1 is lifted up toward the liquid crystal substrate 1 placed on the cassette 20 in three stages. Delimited. 2A is a step S1 in which a voltage of 1 kV is applied to the liquid crystal substrate 1 in the cassette, and FIG. 2B is a step S2 in which the arm 3 is inserted into the cassette, and FIG. These show stage S3 which lifted up the arm and loaded the liquid crystal substrate.
[0026]
FIG. 3 is a diagram showing the time transition of the surface potential of the liquid crystal substrate from S1 to S3 and the amount of charge flowing between the arm and the ground. According to this figure, it can be seen that there is a very good correlation between the substrate surface potential and the charge amount at each stage. Therefore, by measuring the amount of charge flowing between the arm and the ground, the surface potential of the liquid crystal substrate can be determined with high accuracy based on this figure. For this reason, it is possible to measure the charged state of the liquid crystal substrate without causing interference between the transport device and the measuring device. A charge meter (ammeter) that measures the flow of charge between the arm and ground can be used with a small number of measuring devices if it is placed in a transport robot where the flow of liquid crystal substrates merges in a liquid crystal display manufacturing plant or the like. The charged state of many liquid crystal substrates can be grasped efficiently.
[0027]
FIG. 4 is a diagram illustrating a liquid crystal substrate transport apparatus as a reference example of the first embodiment . According to this figure, the measurement sensor 11 a of the surface electrometer (I) is arranged on the liquid crystal substrate 1, and the measurement sensor 11 a of the surface electrometer (II) is arranged on the arm 3. This device is provided to verify whether the surface potential of the liquid crystal substrate can be accurately determined from the surface potential of the arm.
[0028]
FIG. 5 is a diagram showing a time transition of the surface potential of the liquid crystal substrate and the surface potential of the arm including the three stages S1, S2, and S3 of the arm and the cassette shown in FIG. According to this figure, it can be seen that there is a very good correlation between the substrate surface potential and the arm surface potential for each state. Therefore, by measuring the surface potential of the arm, the surface potential of the liquid crystal substrate can be determined with high accuracy based on this figure. For this reason, it is possible to determine the charged state of the liquid crystal substrate without causing interference between the transport device and the measuring device. Also, if the surface electrometer of the arm is placed in a transfer robot where the liquid crystal substrate flows in a liquid crystal display manufacturing factory, etc., the charged state of many liquid crystal substrates can be grasped efficiently with a small number of measuring devices. it can.
[0029]
(Embodiment 2 )
FIG. 6 is a diagram showing a liquid crystal substrate transport device in Embodiment 2 of the present invention. The liquid crystal substrate 1 is transported by adsorbing or mechanically holding the liquid crystal substrate 1 on the arm 3 of the transport device 2. Further, the transport device is provided with connection wiring for connecting the ammeter 4 and the controller 7, and the arm 3, the ammeter 4, the controller 7 and the ground 5.
[0030]
Next, an operation when the liquid crystal substrate 1 fixed to the stage 8 is stored in the cassette 10 will be described with reference to FIG.
(A) First, the liquid crystal substrate 1 is lifted from the stage 8 by the lift-up pins 9, and the arm 3 of the transfer device 2 is inserted between the liquid crystal substrate 1 and the stage 8.
(B) Next, the liquid crystal substrate is attracted to the arm 3, and the arm is pulled back by the action of the arm driving unit 23.
(C) After rotating and moving the transfer device, the arm driving unit 23 inserts the arm into the cassette and releases the suction of the liquid crystal substrate. Further, the liquid crystal substrate is accommodated in the cassette 10 and the arm is pulled back.
[0031]
It is also possible for the arm driving unit 23 to cause the arm 3 to perform the reverse operation to take out the liquid crystal substrate 1 accommodated in the cassette 10 and transport it to the stage 8. The arm 3 and the arm drive unit 23 constitute a main part of the work transfer means or the liquid crystal substrate transfer means.
[0032]
The arm 3 is electrically insulated from the outside and is made of (a) a conductive material or (b) a composite of a conductive material and an insulating material. Examples of the conductive material (a) include conductive resin such as aluminum, stainless steel, metal material, and carbon reinforced material, conductive ceramic, and composite conductive material of metal and ceramic. Examples of the insulating material include an insulating ceramic material such as alumina, an insulating resin material such as an epoxy resin, and glass fiber.
[0033]
The arm 3 is connected to the GND through an ammeter 6 that measures a current value flowing between the arm 3 and a ground (hereinafter, GND) 5.
[0034]
Note that the ammeter 6 may be a coulomb meter, a wattmeter, or a measuring instrument that can cumulatively detect electricity that flows by combining a resistor and a voltmeter. As shown in FIG. 7, when the arm 3 is inserted between the stage 8 and the liquid crystal substrate in order to transport the liquid crystal substrate 1 lifted up onto the stage 8, the arm 3 A current flows between the GND 11. For this reason, it is possible to detect the amount of electricity that has flowed and to determine the charged state of the substrate to be transported based on that value. Here, inserting the arm between the stage and the liquid crystal substrate electrically means that the arm is brought close to the liquid crystal substrate, and the arm may contact the liquid crystal substrate.
[0035]
When taking out the substrate stored in the cassette, as described above, the amount of electricity that flows when the handling arm is inserted into the cassette, the amount of electricity that flows when the substrate is delivered, the amount of electricity that flows when the arm is pulled out from the cassette, The charged state in the substrate and cassette can be determined based on the above.
[0036]
FIG. 8 is a configuration diagram of a liquid crystal substrate transfer device as a reference example of the second embodiment . The difference from the liquid crystal substrate transport apparatus of FIG. 6 in the second embodiment is that a sensor 11a of a surface electrometer 11 is attached in order to measure the potential of the arm 3. As shown in FIG. 9, the arm 3 is inserted between the stage 8 and the liquid crystal substrate 1 to receive the liquid crystal substrate 1 in order to convey the lifted liquid crystal substrate. When the received liquid crystal substrate is charged when the liquid crystal substrate 1 is received, the surface potential of the arm 3 itself rises, and the charge amount of the liquid crystal substrate can be detected based on the value.
[0037]
In order to take out the substrate stored in the cassette, when the arm is inserted into the cassette 3 and the liquid crystal substrate is pulled out, the following phenomenon occurs when the substrate in the cassette is charged. That is, when the arm is inserted into the cassette, the surface potential of the arm increases. Based on this increase in surface potential, the charged state in the cassette can be determined.
[0038]
Further, the charged state of the received liquid crystal substrate can be determined by measuring the surface potential of the arm 3 after the liquid crystal substrate is pulled out from the cassette. In order to clarify the initial potential of the arm 3, it may be necessary to attach a switch 12 as shown in FIG. 10 and bring the arm to the ground potential (zero volts) before measuring the potential. In order to make the potential zero, a resistor having a high resistance value of 1 MΩ to 1000 GΩ may be connected. By using a high resistance, the voltage can be slowly set to zero V in accordance with a time constant CR determined by the resistance R and the capacitance C.
[0039]
In the liquid crystal substrate transfer device shown in FIG. 8 , the surface potential meter 11 is used to measure the potential of the arm 3, but a voltmeter 13 having a high input impedance can also be used as shown in FIG.
[0040]
FIG. 12 is a diagram illustrating another liquid crystal substrate transfer device as a reference example of the second embodiment . In this liquid crystal substrate transport apparatus, in order to measure the potential of the arm 3, the potential of the arm 3 is not directly measured, but is dropped from the arm 3 to the ground 5 through the capacitor 15. This is characterized in that the potential at the position extended from the capacitor 15 by the extension cable is measured by a high input impedance electrometer or surface electrometer.
[0041]
The data detected in the above embodiment or an alarm issued based on the data is sent to a control device that controls an external device, a computer that manages a processing process, or a CIM computer that manages the entire factory. It can be output and used. In addition, when the detected value exceeds the allowable value, it is possible to prevent the phenomenon of dust adhesion due to electrostatic breakdown and high voltage in conjunction with the ionizer.
[0042]
While the embodiments of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments.
(A) The shape of the arm is not limited to two plate-like protrusions, and the number of arms is not limited to one or three as long as it extends so as to be able to stably hold a workpiece on it. Applicable.
(B) The material constituting the arm may be a conductor or a composite of a conductor and an insulator .
(C) The amount of charge induced in the arm is mainly induced by the electrostatic induction phenomenon, but if the phenomenon is such that the state of charge of the arm or the part where the arm is placed can be known, the above measurement It is not limited to the target.
(D) The transfer device may be a transfer robot.
[0043]
The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.
[0044]
【The invention's effect】
According to the liquid crystal substrate transport device of the present invention, in the liquid crystal substrate transport device, the amount of charge flowing between the arm that transports the liquid crystal substrate and the ground is detected, so that the liquid crystal substrate, its mounting site, or the transport device The charged state of the placement site can be determined.
[Brief description of the drawings]
FIG. 1 is a diagram showing a liquid crystal substrate transfer device in Embodiment 1 of the present invention.
FIG. 2 is a diagram showing a positional relationship between a liquid crystal substrate and an arm of a liquid crystal substrate transfer device. (A) A voltage of 1 kV is applied to the liquid crystal substrate and the arm is located outside the cassette, (b) is a step where the arm is inserted into the cassette, and (c) is a step where the arm is lifted up and the liquid crystal substrate is Indicates the stage of loading.
FIG. 3 is a diagram showing a measurement result in the apparatus of FIG. 1;
4 is a diagram showing a liquid crystal substrate transfer device as a reference example of Embodiment 1. FIG.
FIG. 5 is a diagram showing a measurement result in the apparatus of FIG.
FIG. 6 is a diagram showing a liquid crystal substrate transport device in Embodiment 2 of the present invention.
FIG. 7 is a diagram showing another liquid crystal substrate transfer device in Embodiment 2 of the present invention.
FIG. 8 is a diagram showing a liquid crystal substrate transfer device as a reference example of the second embodiment .
FIG. 9 is a diagram illustrating use of the liquid crystal substrate transfer device of FIG.
10 is a diagram in which a ground wire with a switch is provided in a liquid crystal substrate transfer device as a reference example of Embodiment 2. FIG.
11 is a diagram showing a liquid crystal substrate transport apparatus provided with a voltmeter having a high input impedance for measuring the surface potential of an arm in the liquid crystal substrate transport apparatus as a reference example of the second embodiment . FIG.
12 is a diagram showing a liquid crystal substrate transport apparatus as a reference example of the second embodiment, in which an extension cable is provided for measuring an arm potential, and a voltmeter having a high input impedance is provided at the extension point. FIG. is there.
FIG. 13 is a diagram showing a conventional apparatus for directly measuring the surface potential of a substrate in order to measure the charged state of the substrate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Liquid crystal substrate, 2 Conveyance device (robot), 3 Arm, 4,6 Ammeter, 5 Ground, 7 Controller, 8 Stage (one mounting part), 9 Lift up pin, 10 Cassette, 11 Surface potential meter, 11a Surface potential sensor, 12 switch, 13 voltmeter (high input impedance), 14 extension cable, 15 capacity, 20 cassette, 22 recorder, 23 arm drive unit.

Claims (5)

A workpiece transfer device that receives a workpiece and moves it to another location,
An arm for placing and holding the workpiece;
A workpiece charged state detecting means for detecting a charged state of the workpiece by measuring an amount of charge induced in the arm ;
Based on correspondence data that takes correspondence between the amount of charge induced in the arm measured by the workpiece charging state detection means and the charging state of at least one of the workpiece and the portion where the workpiece is placed, A workpiece transfer apparatus comprising: a workpiece charging state indexing unit that calculates a charging state of at least one of the workpiece and a portion where the workpiece is placed . The workpiece transfer device includes an operation control unit that controls the operation of the arm, and the workpiece charging state indexing unit includes the workpiece and the workpiece according to the stage of the operation of the arm obtained from the operation control unit. The workpiece transfer apparatus according to claim 1, wherein the charged state of at least one of the parts on which is placed is determined. The workpiece transfer apparatus, when the value of the charging of the workpiece by the workpiece charging condition indexing means exceeds the allowable value, and a warning signal activated means for emitting warning signals, according to claim 1 or claim 2 Work Conveying device. The said conveyance apparatus is a workpiece conveyance apparatus in any one of Claims 1-3 provided with the ground connection means which connects the said arm and a ground wire so that the electric potential of the said arm may become zero. The workpiece is a liquid crystal substrate, wherein the workpiece transfer device is a liquid crystal substrate transfer apparatus, the workpiece transfer apparatus according to any one of claims 1-4.

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