KR100919407B1 - Liquid crystal dispensing apparatus - Google Patents

Abstract

The present invention discloses a liquid crystal dropping device. According to the invention, at least one nozzle moving relative to the loaded substrate; A liquid crystal supply unit supplying a liquid crystal to the nozzle so that the liquid crystal drops from the nozzle onto the substrate; A defect detection sensor that detects whether the liquid crystal dropping is poor at the lower side of the nozzle while the liquid crystal dropping is in progress by the liquid crystal supplying unit while the nozzle is moving; A maintenance sensor which moves to a position where the liquid crystal dropping failure is detected by the failure detecting sensor after the liquid crystal dropping is finished, determines whether the liquid crystal dropping failure is defective, and calculates a liquid crystal shortage amount; And a control unit controlling the liquid crystal supply unit so that the liquid crystal dropping occurs from the nozzle by the liquid crystal shortage amount calculated by the repairing sensor.

Description

Liquid crystal dropping apparatus

The present invention relates to a liquid crystal dropping apparatus for dropping a liquid crystal onto a substrate to form a liquid crystal layer in manufacturing a liquid crystal display device.

Liquid crystal displays (LCDs) have better visibility than cathode ray tubes (CRTs) and have lower average power consumption and lower heat generation than CRTs of the same screen size. Accordingly, LCDs, along with Plasma Display Panels (PDPs) and Field Emission Display Devices (FEDs), have been spotlighted as next-generation display devices in mobile phones, computer monitors, and television fields.

In general, TFT (Thin Film Transister) LCD panels include a TFT array substrate and a color filter array substrate. The two substrates are separated by approximately 4 to 5 μm, and a liquid crystal layer is formed therebetween. In the periphery of the screen display area, the sealant bonds the two substrates while preventing the inflow of moisture or contaminants into the liquid crystal layer.

On the other hand, there are a liquid crystal dropping method among various methods of forming a liquid crystal layer. The liquid crystal dropping method is a method of dropping a liquid crystal in a space defined by a sealant on a substrate to form a liquid crystal layer, then bonding the substrates together, and curing the sealant to bond the same. In order to form a liquid crystal layer by a liquid crystal dropping system, the liquid crystal dropping apparatus is used.

The liquid crystal dropping device operates to drop the liquid crystal from the nozzle on the substrate while moving the nozzle supplied with the liquid crystal from the syringe in which the liquid crystal is stored relative to the substrate. At this time, the liquid crystal dropping device forms a liquid crystal layer by dropping the liquid crystal to the set total drop amount.

However, in the process of dropping the liquid crystal, a miss drop may occur due to the mixing of bubbles in the liquid crystal supplied to the nozzle. The miss drop causes a liquid crystal dropping failure in which after the liquid crystal dropping is finished, the total drop amount actually dropped is less than the set amount.

According to the related art, after a miss drop is visually confirmed by the operator, the liquid crystal dropping device is manually operated and repaired by the operator's judgment. However, in the case of visually confirming the miss drop and repairing by hand, a skilled worker is required. In addition, if the worker is absent, since the subsequent process does not proceed until the worker returns to the site to repair the miss drop, productivity may be reduced.

In addition, if it is not a miss drop, but the drop of the liquid crystal drop of less than the amount of liquid crystal drop is less than the quantitative drop, it is difficult for the operator to visually determine how much liquid crystal dropping amount is insufficient. Accordingly, there may be a problem that it is difficult to accurately repair the liquid crystal dropping failure.

An object of the present invention is to solve the above problems, to provide a liquid crystal dropping device that can be automated from the process of detecting whether the liquid crystal dropping failure to repair process.

Liquid crystal dropping apparatus according to the present invention for achieving the above object is at least one nozzle relative to the loaded substrate; A liquid crystal supply unit supplying liquid crystals to the nozzles such that liquid crystals drop from the nozzles onto the substrate; A defect detection sensor for detecting a liquid crystal dropping failure at the lower side of the nozzle while the liquid crystal dropping is in progress by the liquid crystal supply unit while the nozzle is moved; A maintenance sensor which moves to a position where the liquid crystal dropping failure is detected by the failure detecting sensor after the liquid crystal dropping is finished, determines whether the liquid crystal dropping failure is defective, and calculates a liquid crystal shortage amount; And a control unit controlling the liquid crystal supply unit so that liquid crystal dropping occurs from the nozzle by the amount of liquid crystal deficiency calculated by the repairing sensor.

According to the present invention, all the processes from the detection of the liquid crystal dropping failure to the maintenance process can be automated. Accordingly, no skilled worker is required, and even if the worker is absent, the liquid crystal dropping failure can be repaired automatically. As a result, the subsequent process may proceed smoothly, and productivity may not decrease.

Further, according to the present invention, even if it is difficult to visually determine how much the amount of liquid crystal is insufficient in the case of under-quantity drop, the amount of liquid crystal deficiency may be accurately calculated and the liquid crystal dropping may be performed by the amount of liquid crystal deficiency. Accordingly, there is an effect that the liquid crystal dropping failure can be easily repaired.

1 is a block diagram of a liquid crystal dropping apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of the failure detecting sensor and the repairing sensor mounted on the head unit in FIG. 1; FIG.

3A and 3B are diagrams for explaining a process of detecting whether a liquid crystal droplet falls from a nozzle by the defect detecting sensor shown in FIG. 2;

4A and 4B are views for explaining a process of repairing a liquid crystal dropping failure after determining a liquid crystal dropping failure by the repairing sensor shown in FIG. 2;

<Brief description of the major symbols in the drawings>

111. Nozzle 120. Liquid crystal supply

130. Defective sensor 140. Repair sensor

150..Control

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a liquid crystal dropping apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the liquid crystal dropping apparatus 100 includes at least one nozzle 111, a liquid crystal supply unit 120, a failure detecting sensor 130, a repairing sensor 140, and a controller 150. It is configured to include.

The nozzle 111 operates to be relatively movable with respect to the loaded substrate 10. The nozzle 111 receives liquid crystal by the liquid crystal supply unit 120 and discharges the liquid crystal onto the substrate 10, thereby forming a liquid crystal layer on the substrate 10.

The liquid crystal supply unit 120 supplies the liquid crystal to the nozzle 111 so that the liquid crystal drops on the substrate 10 from the nozzle 111. The liquid crystal supply unit 120 may be controlled by the controller 150 to allow the liquid crystal to drop from the nozzle 111 in a set amount.

The failure detection sensor 130 detects whether the liquid crystal dropping is poor while the liquid crystal dropping is progressed from the nozzle 111 to the substrate 10 by the liquid crystal supply unit 120 while the nozzle 111 moves. That is, the failure detection sensor 130 detects whether or not the liquid crystal is accurately dropped from the nozzle 111 in a set amount every time the nozzle 111 moves at a predetermined interval.

The dropping of the liquid crystal may occur due to the mixing of bubbles in the liquid crystal supplied to the nozzle 111. For example, there is a miss drop in which the liquid crystal is not dropped at all in the position where the liquid crystal is to be dropped, or a subquant drop in which one drop of the liquid crystal is less than quantitative.

Information about the liquid crystal dropping failure detected by the failure detecting sensor 130 may be provided to the controller 150. The controller 150 recognizes the position of the nozzle 111 corresponding to the point in time at which the information on the liquid crystal drop failure is received from the failure detection sensor 130 as the liquid crystal drop failure position, and stores the liquid crystal drop failure position.

After completion of liquid crystal dropping, the repairing sensor 140 moves to the position where the liquid crystal dropping failure is detected by the failure detecting sensor 130, and determines whether or not the liquid crystal dropping failure is performed. The movement of the repairing sensor 140 may be controlled by the controller 150 storing the liquid crystal dropping failure position. If the liquid crystal dropping is poor, the repairing sensor 140 calculates the amount of liquid crystal shortage. Information about the lack of liquid crystal may be provided to the controller 150.

The controller 150 controls the liquid crystal supply unit 120 so that liquid crystal dropping may be performed on the substrate 10 from the nozzle 111 by the amount of liquid crystal shortage calculated by the repairing sensor 140. In this process, the controller 150 may control the nozzle 111 to move to the position where the liquid crystal dropping failure is detected. In addition, the controller 150 controls the entire liquid crystal dropping apparatus 100 to allow the liquid crystal to be dropped in a set amount on the substrate 10.

An example of the operation of the liquid crystal dropping device 100 configured as described above is as follows.

If liquid crystal dropping failure such as miss drop or under-quantification drop occurs while the liquid crystal dropping is in progress from the nozzle 111, the defect detection sensor 130 detects whether the liquid crystal dropping failure is provided to the controller 150. The controller 150 recognizes and stores the liquid crystal dropping failure position. When the liquid crystal dropping is finished, the controller 150 moves the repairing sensor 140 to the liquid crystal dropping failure position.

The repairing sensor 140 determines whether the liquid crystal dropping is poor, and calculates and provides the amount of liquid crystal shortage to the controller 150 when the liquid crystal dropping is poor. The controller 150 controls the liquid crystal supply unit 120 to cause liquid crystal dropping from the nozzle 111 to the substrate 10 by the amount of liquid crystal shortage. As a result, the liquid crystal dropping failure is repaired, and the liquid crystal layer may be formed with a dropping amount set on the substrate 10.

As described above, all processes from the detection of the liquid crystal dropping failure to the repairing process are automated. Therefore, the operator visually checks whether the liquid crystal dropping is poor, and then, compared to the process of manually operating and repairing the liquid crystal dropping apparatus at the operator's discretion, no skilled worker is required. In addition, even if the worker is absent, since the liquid crystal dropping defect is automatically repaired, the subsequent process can proceed smoothly. As a result, productivity decrease may not occur. In addition, even if it is difficult to visually determine how much the amount of liquid crystal is insufficient in the case of under-quantity drop, the amount of liquid crystal deficiency can be accurately calculated and liquid crystal dropping can be performed by the amount of liquid crystal deficiency. Accordingly, poor liquid crystal dropping can be easily repaired.

Meanwhile, the nozzle 111 may be mounted to the nozzle mounting block 112 of the head unit 110 to move relative to the substrate 10. Here, the head unit 110 is supported by the head support portion 102, the head support portion 102 is installed in the frame 101 to be horizontally movable in one direction. In addition, the head unit 110 is installed to be horizontally movable in a direction perpendicular to the moving direction of the head support part 102. Accordingly, the nozzle 111 mounted on the head unit 110 may be relatively moved relative to the substrate 10.

When a plurality of unit panels are formed on the upper and lower glass substrates of a large area to increase productivity, the nozzles 111 may be provided in plural numbers. The unit panel corresponds to an LCD panel that is employed one for each LCD. The plurality of nozzles 111 are disposed at least one unit per unit panel so that the liquid crystal is dropped. Accordingly, since a liquid crystal layer may be simultaneously formed on a plurality of unit panels, productivity may be improved.

The liquid crystal supply unit 120 may include a syringe 121 in which the liquid crystal is stored and a pump module 122 to supply the liquid crystal to the nozzle 111. The pump module 122 is configured to apply a discharge pressure to the liquid crystal when the liquid crystal is supplied from the syringe 121 to the nozzle 111, thereby enabling the liquid crystal to be discharged from the nozzle 111. In addition, the pump module 122 is configured to have a valve function of opening and closing the flow of liquid crystal between the syringe 121 and the nozzle 111, so that the liquid crystal is supplied from the syringe 121 to the nozzle 111 by a set amount. To be able.

As another example, the liquid crystal supply unit 120 may be provided with an air pressure supply instead of the pump module 122. The pneumatic pressure supply unit is configured to apply the discharge pressure to the liquid crystal by supplying air or gas having a predetermined pressure into the syringe 121, thereby allowing the liquid crystal to be discharged from the nozzle 111.

The failure detecting sensor 130 may be disposed under the nozzle 111 to detect a liquid crystal dropping failure while the liquid crystal dropping is in progress. The defect detection sensor 130 may be a laser sensor. As illustrated in FIG. 2, the laser sensor includes a light emitter 131 that emits a laser beam, and a light receiver 132 that receives light emitted from the light emitter 131 and processes a received signal.

The light emitting unit 131 and the light receiving unit 132 are disposed on both sides of the light emitting unit 131 with the nozzle 111 interposed therebetween. The light emitting unit 131 is disposed so that the emitted light passes through the lower side of the nozzle 111, and the light receiving unit 132 is arranged to receive the light emitted from the light emitting unit 131.

The light emitter 131 may include a plurality of light emitting regions to widen the detection area. To this end, the light emitting regions may be arranged spaced apart at regular intervals along the horizontal direction. The plurality of light emitting portions allow the drop of the liquid crystal droplet to be detected even if the liquid crystal droplet falling from the nozzle 111 is inclined to fall down rather than directly falling down.

When the light receiving unit 132 determines that the light receiving signal acquired for a predetermined time from the time when the nozzle 111 moves to the liquid crystal dropping position has a constant value, the light receiving unit 132 may recognize the liquid crystal dropping failure such as a miss drop. .

That is, during the set time, as illustrated in FIG. 3A, liquid crystal may be dropped from the nozzle 111 and may not pass between the light emitting unit 131 and the light receiving unit 132. Then, the light emitted from the light emitting portion 131 proceeds as it is and enters the light receiving portion 132. Therefore, the received light signal acquired during the set time has a constant value within the tolerance range. In this case, the light receiving unit 132 determines that the received light signal has a constant value for a predetermined time and recognizes that the liquid crystal drop is a miss drop without falling.

On the other hand, during the set time, as shown in FIG. 3B, the liquid crystal may be dropped from the nozzle 111 and may pass between the light emitter 131 and the light receiver 132. Then, the light emitted from the light emitting unit 131 is reflected by the liquid crystal droplets while the liquid crystal droplets pass, and is not incident to the light receiving unit 132. Therefore, the light reception signal value obtained before and after the liquid crystal droplet passes between the light emitting unit 131 and the light receiving unit 132 and the light reception signal value obtained while the liquid crystal droplet passes between the light emitting unit 131 and the light receiving unit 132 are different. . In this case, the light receiving unit 132 recognizes that the liquid crystal drops have fallen.

The light receiving unit 132 may recognize the liquid crystal dropping failure if there is a difference in comparison with the received signal waveform and the reference signal waveform acquired during the set time.

That is, during the set time, if the drop of liquid crystal falling from the nozzle 111 is less than or more than the quantity of defect, the shape of the liquid crystal drop that is defective is different from the shape of the liquid crystal droplet that is the quantity. Accordingly, the received signal waveform obtained from the light receiver 132 with respect to the defective liquid crystal droplet is different from the received signal waveform obtained from the light receiver 132 with respect to the liquid crystal droplet which is defective.

The light receiving unit 132 stores the received signal waveform obtained with respect to the liquid crystal droplet as the reference signal waveform. The light receiving unit 132 compares the light receiving signal waveform obtained for the liquid crystal drop falling from the nozzle 111 with the reference signal waveform, and if it is determined to be the same, recognizes that the liquid crystal droplet is a quantitative liquid crystal. The light receiver 132 determines that the two waveforms are the same when the difference value between the two waveforms satisfies the tolerance range.

If the light receiving unit 132 compares the obtained light receiving signal waveform with the reference signal waveform and judges that there is a difference, the light receiving unit 132 recognizes that the defective liquid crystal droplet is defective. The light receiver 132 determines that the two waveforms are different when the difference value between the two waveforms is outside the tolerance range. On the other hand, the light receiving unit 132 only receives the light and converts it into an electrical signal, the signal processing unit for processing the converted electrical signal may be provided in the controller 150.

As described above, since the light emitting unit 131 emits light and the light receiving unit 132 processes the light receiving signal to detect the liquid crystal dropping failure, the liquid crystal dropping failure can be detected in a non-contact manner. Therefore, since no influence is applied to the liquid crystal dropped from the nozzle 111 in the process of detecting the liquid crystal drop failure, the liquid crystal drop failure due to the detection process may not occur. As another example, the failure detecting sensor 130 may be formed of another non-contact vision sensor.

Meanwhile, the defect detection sensor 130 may further include a liquid crystal splash prevention cover 136. The liquid crystal splash prevention cover 136 prevents the liquid crystal dropped from the nozzle 111 to bounce back toward the nozzle 111 by hitting the substrate 10, thereby preventing the liquid crystal from flowing between the light emitting unit 131 and the light receiving unit 132. . Thus, the liquid crystal dropping failure can be detected accurately.

The liquid crystal splash prevention cover 136 may be disposed under the light emitting part 131 and the light receiving part 132, and may have a structure in which a hole 136a is formed in a portion corresponding to the lower part of the nozzle 111.

On the other hand, the repair sensor 140 is composed of a vision sensor, as shown in Figure 4a, to acquire the image at the position (EP) where the liquid crystal drop failure is detected and to process the obtained image, to determine whether the liquid crystal drop failure can do. Here, when it is determined that the repair sensor 140 is a miss drop, the maintenance sensor 140 may output the amount of liquid crystal of one drop to the controller 150 as a lack of liquid crystal. If after the liquid crystal dropping is finished, if the controller 150 recognizes that there is only a miss drop, the control unit 150 moves the nozzle 1111 to the position EP at which the miss drop has occurred, as shown in FIG. 4B, and the nozzle 111. A drop of liquid crystal is discharged from

If it is determined that the repair sensor 140 is an under-quantity drop or an over-quantity drop, the under-quantity drop volume or over-quantity drop volume is measured from the acquired image. Thereafter, the repair sensor 140 may compare the measured value with the reference value, calculate the amount of liquid crystal shortage or the amount of liquid crystal excess, and output the calculated amount to the controller 150. Here, the reference value corresponds to the volumetric drop volume value.

The method for measuring the subquantitative drop volume or the excess volume of the drop volume from the image obtained by the repair sensor 140 may vary. An example of the measuring method is as follows. The obtained image may include different color information according to the surface height of the dropped liquid crystal droplets. Using this, the repairing sensor 140 may calculate the volume of the dropped liquid crystal droplets after converting the surface height data of the dropped liquid crystal droplets based on the acquired color data of the image.

On the other hand, after the miss drop or under-quantity drop, the liquid crystal may remain at the end of the nozzle 111. In this case, the residual liquid crystals may be dropped together in a subsequent dropping process, and there may be a drop in quantity. When there is a miss drop or under-quantity drop and an over-quantity drop as described above, after the dropping of the liquid crystal is finished, the controller 150 compares the value of the liquid crystal excess amount to the input liquid crystal deficit amount and the set liquid crystal drop amount value. To calculate.

If the controller 150 determines that the liquid crystal is insufficient, the controller 150 moves the nozzle 111 to a position where a miss drop or under-quantity drop occurs, and discharges the liquid crystal from the nozzle 111 by the liquid crystal shortage amount.

Here, the controller 150 may move the nozzle 111 directly above the position where the miss drop or under-quantity drop occurs to allow the liquid crystal dropping to occur. As another example, the controller 150 may move the nozzle 111 next to a position where a miss drop or under-quantity drop occurs so that the liquid crystal drop may be performed. In this case, even if bubbles remain at a position where a miss drop or underquantity drop occurs, the liquid crystal may be dropped next to the remaining bubbles instead of directly dropping on the remaining bubbles. Therefore, since the liquid crystal is dropped on the remaining bubbles, the phenomenon in which the remaining bubbles are mixed in the liquid crystal layer can be prevented.

Meanwhile, the repair sensor 140 extracts an image determined to be the same as compared with the acquired image and the previously input images, and outputs the liquid crystal shortage or liquid crystal excess corresponding to the extracted image to the controller 150. Can be.

Here, the pre-input images are images in which the amount of liquid crystal shortage or the amount of liquid crystal excess is set based on the image of the liquid crystal drop of quantity. In addition, the repair sensor 140 determines that the two images are the same when the difference between the two images to be compared satisfies the tolerance range. Meanwhile, the repair sensor 140 only acquires an image, and the image processing unit for processing the acquired image may be provided in the controller 150.

INDUSTRIAL APPLICABILITY After the liquid crystal dropping is finished on the substrate, the present invention can be applied to a field in which it is necessary to repair the liquid crystal dropping failure.

Claims (9)

At least one nozzle moving relative to the loaded substrate; A liquid crystal supply unit supplying liquid crystals to the nozzles such that liquid crystals drop from the nozzles onto the substrate; A defect detection sensor that detects whether a liquid crystal drop is defective and a defective position at the lower side of the nozzle while the liquid crystal is dropped by the liquid crystal supply unit while the nozzle is moved; A maintenance sensor which moves to a position where the liquid crystal dropping defect is detected by the failure detecting sensor after the liquid crystal dropping is finished, and determines whether the liquid crystal dropping defect is defective and calculates the amount of liquid crystal shortage; And A control unit which controls the liquid crystal supply unit such that liquid crystal dropping occurs from the nozzle by the amount of liquid crystal shortage calculated by the repairing sensor; Liquid crystal dropping device having a. The method of claim 1, The defect detection sensor is made of a laser sensor, And the laser sensor includes a light emitting portion arranged so that the emitted laser light passes through the lower side of the nozzle, and a light receiving portion which receives light emitted from the light emitting portion and processes a light receiving signal. The method of claim 2, The light receiving unit determines that the received light signal has a constant value for a predetermined time from the time when the nozzle is moved to the liquid crystal dropping position, or the difference is compared with the obtained light receiving signal waveform and the reference signal waveform. And a liquid crystal dropping device, the liquid crystal dropping device being recognized. The method according to any one of claims 1 to 3, The repair sensor is a liquid crystal dropping device comprising a vision sensor, to obtain an image at the position where the liquid crystal drop failure is detected and to process the obtained image, to determine whether the liquid crystal drop failure. The method of claim 4, wherein If it is determined that the repair sensor is a miss drop, outputting one drop of liquid crystal as an insufficient liquid crystal to the controller; If it is determined that the repair sensor is an under-quantity drop or an over-quantity drop, the under-quantity drop volume or over-quantity drop volume is measured from the acquired image, and then the measured value and the reference value are compared to determine the amount of liquid crystal deficiency or liquid crystal excess. The liquid crystal dropping apparatus, which is calculated and output to the control unit. The method of claim 5, If you have a miss drop or under drop drop and an over drop drop, And the control unit compares a value reflecting the liquid crystal excess amount to the input liquid crystal deficit amount and the set liquid crystal drop amount value, and calculates the liquid crystal shortage amount when it is determined that the liquid crystal is insufficient. The method of claim 4, wherein The repair sensor extracts an image which is determined to be the same as compared with the acquired image and the previously input images, and outputs a liquid crystal shortage or liquid crystal excess corresponding to the extracted image to the controller. Device. The method of claim 7, wherein If you have a miss drop or under drop drop and an over drop drop, And the control unit compares a value reflecting the liquid crystal excess amount to the input liquid crystal deficit amount and the set liquid crystal drop amount value, and calculates the liquid crystal shortage amount when it is determined that the liquid crystal is insufficient. The method according to any one of claims 1 to 3, The control unit is a liquid crystal dropping device, characterized in that the liquid crystal dropping is made by moving the nozzle directly above or next to the position where the liquid crystal dropping failure is detected.