CN100576030C - Equipment for inspecting liquid crystal panels and method for manufacturing liquid crystal displays - Google Patents

Abstract

Interact with the composite liquid crystal panel of simulated solution crystal display work with measuring station, and the method for making and testing this liquid crystal board.Composite liquid crystal panel can provide operating voltage to liquid crystal board district, a plurality of unit.Measuring station is provided with working power, radiation source and first and second polarizer.When power supply is applied on the composite liquid crystal panel, just produce image.This image will manifest the defective in the liquid crystal board district, unit.Useful is that measuring station helps the identification of problem when tilting.

Description

Equipment for inspecting liquid crystal panels and method for manufacturing liquid crystal displays

This application claims the benefit of Korean Patent Application Nos. P2002-10197 and P2002-13527 filed on February 26, 2002 and March 13, 2002, respectively, which are incorporated herein by reference.

This application is a divisional application of the application No. 02157180.5 filed on December 16, 2002 and the title of the invention is "liquid crystal panel, equipment for inspecting liquid crystal panel and method for manufacturing liquid crystal display".

technical field

The invention relates to a method of manufacturing and inspecting a liquid crystal display panel.

Background technique

With the development of the information society, there is an increasing demand for displays that can produce high-quality images with low power consumption, thin body, and light weight. In order to meet these demands, various flat panel display devices have been studied, including liquid crystal displays (LCDs), plasma displays (PDPs), electroluminescence displays (ELDs), and vacuum fluorescent displays (VFDs). Some of these display technologies are already used in information display.

Among various flat panel display devices, LCD may be the most widely used one. In fact, in portable devices such as notebook PCs, LCD technology has replaced cathode ray tube (CRT) technology as the display method of choice. In addition, LCD devices are increasingly being used even in desktop PCs and TV monitors.

A basic LCD includes opposing substrates and a liquid crystal material disposed between the substrates.

Liquid crystals are material phases with properties intermediate between liquids and solids. Liquid crystals have the fluidity of liquids but the long-range crystal order of solids. Since liquid crystals have long-range crystal order and fluidity, liquid crystals have optical anisotropy.

The manufacture of an LCD requires multiple processes, including forming the array, forming color filters (CF), filling (dispensing) liquid crystals, and making components (described in order).

The process of forming the matrix includes deposition, photolithography, and etching on a first substrate (TFT substrate) to form a thin film transistor (TFT) array. The process of forming a color filter (CF) includes forming red, green, and blue color filters on a black matrix, and forming an ITO (indium tin oxide) film functioning as a common electrode on a CF substrate.

The liquid crystal filling (dispensing) process includes assembling the TFT substrate and the CF substrate together. Generally, a TFT substrate and a color filter substrate are assembled to form a small gap between the substrates. Then, liquid crystal is injected through the gap opening to form a liquid crystal panel.

In the process of making the module, the drive circuit that processes the input and output signals is connected to the liquid crystal panel. In addition, a frame is added to make a liquid crystal module.

LCDs are usually assembled on a production line. In the prior art, cassettes each containing a plurality of TFT substrates or a plurality of color filter substrates are input to a loading device. Each TFT substrate includes a plurality of gate lines extending in one direction and a plurality of data lines crossing vertically. Thin film transistors and pixel electrodes are arranged on the black matrix in the area between the gate line and the data line. Each CF substrate has a black matrix, color filters and common electrodes. Thus, the black matrix will block light leakage other than the desired light from the pixel area.

Each TFT substrate or color filter substrate is individually taken out of the cassette by a loading device and sent to the input end of the alignment layer production line. A production line comprising manually programmed robots forms an alignment layer on each substrate (cf. alignment process step 1S in FIG. 1 ).

Step 1S includes cleaning the respective substrates so that a uniformly oriented coating can be formed. Then, an alignment material is coated on the substrate. Next, the alignment material is cured by removing the solvent in the alignment material and/or causing a thermal polymerization reaction of the alignment material. After curing, the alignment material is mechanically rubbed to form a surface that fixes the liquid crystals to align them uniformly. Finally, the cleaning process is performed again, and an alignment layer is formed.

After the step 1S of forming the alignment layer is completed, several processes need to be performed to form the gap. These steps can be performed sequentially or in parallel. The gap forming process includes a cleaning process (step 2S) of cleaning the substrate (TFT substrate or color filter substrate) and a spacer dispersion process of dispersing the spacer on the substrate (step 3S). Gaskets are used to maintain a constant and consistent gap thickness.

Instead of the gap forming step, the sealant coating step (step 4S) may be performed on the substrate (one substrate [TFT or CF] undergoes the gap forming step, and the other substrate is subjected to sealant coating). After the cleaning step 2S, a sealing material is placed on the peripheral portion of the substrate. Finally, the TFT substrate is bonded to the CF substrate with a sealing material to form an assembly board. It should be noted that the sealant coating process (4S) is performed on one substrate (TFT or CF), and the spacer dispersion is performed on the other substrate. Therefore, as shown in Figure 1, the production line has two divisions. One section performs washing (step 2S) and dispensing of gasket (step 3S). Another subsection performs cleaning (step 2S) and sealing (step 4S).

After the spacer dispersion process 3S and the sealant application process 4S, an assembly process (5S) including aligning, heating, and pressing the TFT substrate and the color filter substrate together to produce an LCD panel is performed. In the assembly process, the TFT substrate and the color filter substrate are arranged in an opposing form and combined with each other to form an LCD panel.

After the assembly process (step 5S), a cutting process (step 6S) is performed in which the assembled hollow LCD panel is cut into a plurality of unit panels by scribing and splitting the assembled hollow panel.

After the cutting process (step 6S), liquid crystal is injected into the cell plate through the liquid crystal injection hole on the sealing material, and then the injection hole is sealed (step 7S).

Finally, after step 7S, referring to step 8S, each liquid crystal cell is polished (cut burrs are removed) and inspected. Thus, a liquid crystal cell was fabricated.

FIG. 2 schematically shows a typical prior art liquid crystal perfusion process after each step 6S. Liquid crystal 25 is placed in a container 30 as shown in the figure. The container 30 is inserted in the vacuum chamber 20 . The vacuum chamber 20 is evacuated for a certain period of time to remove water adhering to the inner wall of the container 30, water in the liquid crystal 25, and microbubbles in the liquid crystal 25.

Referring further to FIG. 2, the seals of several cell plates 40 are then immersed in the liquid crystal. Nitrogen (N2) gas is introduced into the chamber 20 to create atmospheric pressure. The pressure difference between the cell plate 40 and the vacuum of the chamber 20 forces the liquid crystal into the cell plate.

After the liquid crystal 25 is injected into each unit plate 40, the liquid crystal injection port is sealed. Then the unit liquid crystal panel is cleaned. Step 6S is thus completed.

Although the above method has certain benefits, there are some problems with injecting liquid crystals by the above method. For example, the liquid crystal injection process takes a long time, for example, it takes more than 10 hours to perfuse a 10-inch panel. The reason for the long infusion time is that the gap between the substrates is small and the area to be infused is relatively large. This problem is particularly serious when making large-area LCDs. In addition, the remaining liquid crystal material cannot be reused due to the liquid crystal being polluted and/or degraded due to impurities and chemical reactions, so the above method will cause waste of liquid crystal. In order to overcome these problems, a method of applying liquid crystals by a drop casting method is proposed.

The liquid crystal dropping method will be briefly described below with reference to FIG. 3 . It should be noted that the TFT and color filter substrates are preferably large glass substrates that include multiple panel regions (TFT arrays and color filter arrays) that ultimately form each LCD display. In the liquid crystal dropping method, liquid crystal is dropped onto each plate area of the substrate. When the first and second substrates are assembled together, the dripped liquid crystals will then be dispersed on the plate area of the entire substrate.

Referring now to FIG. 3, the alignment step 100S is performed according to the above-mentioned method, so that the liquid crystal has a uniform directionality. Then, referring to step 102S, the TFT and CF substrates are cleaned.

Next, in step 103S, the cleaned CF substrate is placed on a sealant dispenser and sealant is dispensed around the perimeter of each substrate pad. The sealant is preferably a light/thermosetting resin. It should be noted that the liquid crystal injection ports/openings are no longer required.

Meanwhile, in step 105S, the cleaned TFT substrate is placed on an Ag (silver) dispensing device to form silver dots on the common electrode power supply line of the TFT substrate. Then, in step 106S, the TFT substrate is placed on the LC dispenser. Next, the liquid crystal is dropped onto the plate area of the substrate.

Subsequently, in a vacuum assembly and curing step 107S, the TFT and CF substrates are placed in a vacuum chamber. Afterwards, the TFT and CF substrates are assembled together so that the dripped liquid crystals evenly fill the gaps between the plate areas of the substrates. The encapsulant is then cured to form the combined LC panel. A combined LC panel is a large panel with multiple cell liquid crystal panel regions.

In the S/B (scribing/breaking) step 108S, the combined LC panels are separated into individual LC panels. The S/B step 108S includes a scribing process of forming cut lines on the glass surface with a diamond-based pen, and a cleaving process of separating each LC panel by applying force.

The surface of each LC panel is ground to remove burrs/flaws in a grinding step 109S. Then, a step 110S of inspecting the appearance and A/P (automatic inspection) of each LC panel is performed, thereby completing the manufacturing process of the LC display.

The A/P detection is an electrical detection of each LC panel with a device that applies a predetermined voltage to an input connected to a gate line and a data line of a TFT substrate in a unit LC panel. A/P inspection is very useful for checking for defects such as cell gaps or LC leaks.

After the step 110S, the driver IC, the backlight source and the combination frame are integrated on each LC board to form an assembly.

Unfortunately, the liquid crystal drip method has its own problems. For example, after the combined LC boards are cut into individual LC boards, the appearance and electrical integrity are inspected by workers. Since each LC panel must be tested by driving the drive lines of all the individual LC panels in a predetermined pattern, it is difficult and time consuming to perform the test. This increases the inspection time and makes the worker very tired.

Therefore, it is very beneficial to adopt a method for automatically checking the electrical comprehensive performance and visual performance of the combined LC display. More beneficially, the adopted method of automatically checking the electrical integrity and visual performance of the combined LC display will not bring undue pressure to the workers or significantly affect the production.

Contents of the invention

Accordingly, the present invention is to provide an apparatus for inspecting liquid crystal panels and a method of making individual liquid crystal panels in a manner that substantially overcomes one or more of the problems due to limitations and disadvantages of the prior art.

An advantage of the present invention is to provide a device for testing composite liquid crystal panels, which has a specific electrode structure. Another object of the present invention is to provide a method of making a combined liquid crystal display with a specific electrode structure so that the combined liquid crystal display panel can be divided into individual liquid crystal panels, and it is more beneficial that only a small number of tests are required for each liquid crystal panel .

Other features and advantages of the present invention will be given in the following description, some of which may be apparent to those skilled in the art in subsequent examinations or obtained by practicing the present invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description, claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposes of the present invention, as generally and broadly described, a method of making a liquid crystal display according to the present invention includes preparing first and second substrates which when bonded together form Combination liquid crystal panel with multiple unit LC panel regions. The method further includes assembling the first and second substrates together by bonding, and then performing an A/P inspection that checks for electrical failures and visual defects of the combined liquid crystal panel.

According to another aspect of the present invention, fabricating a liquid crystal display includes the steps of: preparing first and second substrates, each substrate having a plurality of substrate plate regions, on a substrate plate region surrounding one of the first and second substrates applying a sealant, dripping liquid crystal on the substrate plate region of the other of the first and second substrates, making the substrate plate regions of the first and second substrates face each other by bonding the first and second substrates together, Form a combined liquid crystal panel with multiple unit liquid crystal panel areas, perform A/P (automatic detection) testing to determine electrical faults and visual defects in the unit large liquid crystal panel area, and cut the combined liquid crystal panel to form multiple individual LCD panels, and then grind the surface of a single LCD panel.

According to another aspect of the present invention, the detection device comprises a worktable having a rotating shaft capable of tilting the workbench; a light source disposed inside the workbench capable of achieving substantially uniform light radiation; A first polarizer above the light source and capable of covering the combined liquid crystal panel to be tested; and at least two voltage ports, which can provide a predetermined voltage to the combined liquid crystal panel.

Apparently, the above general description of the present invention and the following detailed description are exemplary and explanatory, and are intended to further explain the invention to be protected by the claims of the present invention.

Description of drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description explain the principle of the invention.

Fig. 1 shows the flow chart of making LCD by vacuum injection method;

Figure 2 shows vacuum implantation according to the method used in the flow chart of Figure 1;

Fig. 3 shows the flow chart of making LCD by applying (dropping) liquid crystal on the substrate;

Fig. 4 schematically shows the first substrate of the LC panel according to one embodiment of the present invention;

Figure 5 schematically represents an LC panel according to one embodiment of the present invention;

Figure 6 shows an enlarged cross-sectional view of area 'A' in Figure 5;

Fig. 7 represents the flow chart of LCD manufacturing method according to one embodiment of the present invention;

Figure 8 shows a detection device according to one embodiment of the present invention; and

Fig. 9 schematically shows the structural arrangement of the LC panel according to one embodiment of the present invention.

Detailed ways

Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

Figure 4 schematically shows the first substrate of the LC panel according to one embodiment of the present invention, Figure 5 schematically shows the unit LC panel according to one embodiment of the present invention, Figure 6 shows the area 'A' in Figure 5 The magnified sectional view of Fig. 7 represents the flow chart of the LCD manufacturing method according to one embodiment of the present invention, Fig. 8 represents the detection equipment according to one embodiment of the present invention, and Fig. 9 schematically represents the process according to the present invention An embodiment of the structural arrangement of the combined LC panel.

Referring to FIG. 4 and FIG. 5 , the first and second substrates 100 and 200 shown are TFT array substrates and color filter array substrates, respectively. The first substrate 100 includes a plurality of first substrate plate areas 100a, and the second substrate 200 includes a set of second substrate plate areas matching the aforementioned plate areas. The completed first and second substrates 100 and 200 are placed on a cassette entering an LC (liquid crystal) production line. Each of the first substrate pad regions 100a includes a plurality of gate lines 50 arranged in one direction at predetermined intervals, and a plurality of data lines 60 arranged in a vertical direction at predetermined intervals. A matrix type pixel area 70 is defined by gate lines 50 and data lines 60 . A plurality of thin film transistors TFT and pixel electrodes are formed on the pixel area 70 . The image display area 50 is constituted by a plurality of pixel areas 70 . In addition, although not shown in the figure, the gate of each thin film transistor TFT is connected to the corresponding gate line 50, and the source is connected to the corresponding data line. The drain of each TFT is connected to the pixel electrode in the pixel region 70 . In addition, a plurality of gate and data lines 50 and 60 are connected to gate and data pads 90 and 110, which are disposed along the periphery of the TFT unit substrate region 100a.

In addition, the first and second metal lines 121 and 123 are formed in column and row directions near the edge of the first substrate 100 . External ports 121 a and 123 a are formed at ends of the first and second metal lines 121 and 123 . The first and second metal lines 121 and 123 are wires which will be used to test the combined liquid crystal panel during the A/P test. The first and second metal lines 121 and 123 may be discarded at last.

The column shorting bar 120 and the row shorting bar 122 of each substrate pad short the ends of the gate line 50 and the data line 60 by connecting to the pads 90 and 110, respectively. The row short bar 122 is electrically connected to the first metal line 121 , and the column short bar 120 is electrically connected to the second metal line 123 . As a result, all gate lines 50 on all first substrate pads 100a are connected together, and all data lines 60 on all first substrate pads 100a are connected together. It should be noted that the static electricity generated on any one of the gate pad 90 and the data pad 110 will be discharged to all the plate regions 100a of the first substrate through the short bar.

Referring particularly to FIG. 5 , a plurality of second substrate plate regions 200 a are formed on a second substrate 200 . Each second substrate region 200a includes a black matrix layer 210 that prevents light from passing through the second substrate region 200a except for the pixel region 70 . The second substrate pad area also includes color filters for the three primary colors, common electrodes arranged along the entire surface of the second substrate, and column spacers (favorable for large LCDs). The column spacers are formed corresponding to the gate lines and the data lines on the first substrate 100 .

The black peripheral portion 220 is provided to block unnecessary light from the periphery of the display area 50 . The first and second substrates 100 and 200 having the first and second substrate plate regions 100a and 200a are assembled together using a sealant made of photo-curable or thermosetting resin.

Figure 6 shows an enlarged cross-sectional view of area 'A' in Figure 5 . As shown in the drawing, an insulating layer 127 is interposed between the column and row shorting bars 120 and 122 on the first substrate 100 to insulate the column and row shorting bars 120 and 122 from each other. The above-structured first and second substrates 100 and 200 were fabricated into a single LC panel using the process flow of FIG. 7 . As shown in the figure, a loader is used to transport the first and second substrates to the LC cell processing station. The LC cell processing station performs three main steps, steps 500, 600 and 700.

The first step 500 is an alignment process, which imparts uniform directionality to the liquid crystal. The alignment process is completed through the following steps: substrate cleaning 20S, subsequent alignment layer printing 21S, subsequent alignment layer plasticization 22S, subsequent alignment layer inspection 23S and finally alignment layer rubbing 24S.

Some explanation of step 500 is useful. After the particles are removed by the cleaning process 205, the substrate is ready for printing. The alignment layer liquid was dripped between Doctor and Anilox rolls rotating in a dispenser. The alignment layer liquid remains in the form of a liquid film on the surface of the Anilox roll and is sent to a printing roll having a printing rubber plate. An alignment layer liquid film is then applied to the first and second substrates by transfer printing.

Next, referring to step 22S, the alignment layer is plasticized through a drying process. Drying allows the solvent in the alignment layer liquid to evaporate. The alignment layer is then inspected (step 23S) and rubbed (step 24S).

Then proceed to the second step 600 . The substrate with the alignment layer is cleaned (step 25S). If the substrate is a CF substrate, then at step 26S, a sealant is applied around the pad area of the second substrate. It should be noted that there is no injection port left on the sealant.

If the substrate is a TFT substrate, the substrate is cleaned in step 25S. Then, silver (Ag) dots are formed in step 27 so as to be able to electrically connect the TFT substrate to the common electrode of the CF substrate. Subsequently, liquid crystal is applied to the first substrate plate area at a position corresponding to the inner side of the sealant on the color filter substrate. Advantageously, the liquid crystal is applied by instilling liquid droplets in step 29S.

Liquid crystal dripping is done by removing air bubbles in the liquid crystal with a vacuum, placing the LC dripping device on the LC dispensing device, placing the first substrate on the LC dispensing device, and dripping the liquid crystal on the first substrate with the LC dripping device Note.

Although the solution of disposing the sealant on the CF substrate and dripping the liquid crystal on the TFT substrate is discussed above, in practice, it is also possible to dispose the sealant on the TFT substrate and drip the liquid crystal on the CF substrate.

After the second step 600, a third step 700 is performed. The first and second substrates are assembled together in a vacuum assembly apparatus such that the panels of the first and second substrates face each other. Ultraviolet rays (UV rays) are then irradiated onto the sealant to cure the sealant, thereby forming a combined LC panel.

Although not shown in the drawings, the assembly process is performed in the following steps. First, it is preferable to mount the first substrate on the platform of the vacuum container movable in the horizontal direction by using the first suction device. Then, the second substrate is fixed on the second adsorption device by vacuum suction, so that the second substrate is placed on the first substrate. Then close the vacuum chamber and create a vacuum. Thereupon, the second suction device is lowered leaving a predetermined interval between the first and second substrates. The first substrate is then moved horizontally into alignment with the second substrate.

Thereafter, the second suction device descends through the encapsulant to assemble the second substrate to the first substrate. The first and second substrates are then pressed together and the liquid crystal is allowed to fill the liquid crystal cell panel area (the liquid crystal is dispersed across the first substrate liquid crystal cell panel area). Thus, a large LC panel having a plurality of liquid crystal cell panel regions is produced. Subsequently, the plate was taken out from the vacuum chamber, and the well was irradiated with ultraviolet light, thereby curing the sealing material.

Then, referring to step 40S, electro-optical detection is performed. Electro-optical detection is carried out as follows. Referring now to FIG. 7 and FIG. 8 , in step 41S, the large LC panel is placed on the detection device 400 by the robot. As shown in FIG. 8 , the detection device 400 includes a workbench 300, at least three protrusions 310 arranged to have a minimum contact area between the workbench 300 and the combined LC panel placed by the robotic arm, a tiltable rotating member 320, and The light source 330 provided in the workbench 300 . The light source 330 uniformly radiates light from the inside of the table. The first polarizer 327 is disposed above the light source 330 . A fixing portion (not shown in the figure) fixes the combined LC panel to the table 300 when the table is rotated.

Referring to FIG. 4 , the detection device 400 further includes at least two voltage ports that provide voltages to the external ports 121a and 123a (see FIG. 4 ), and the external ports 121a and 123a can provide voltage to the gate pad 90 and the data pad 110 (refer to FIG. 5 ). electrical energy.

Referring now to FIG. 8, after the combined LC panel is placed on the inspection device 400 by the robot, the inspection device 400 is rotated by a predetermined angle by means of the rotating member 320 (see steps 41S and 42S). The combined LC board receives external power through the external port.

Next, the user performs an A/P test with a second polarizer 329 of predetermined dimensions coupled to the detection device whereby the first and second polarizers sandwich the combined LC panel ( See step 44S).

Figure 9 shows the arrangement of the combined LC panel according to one embodiment of the present invention. As shown in the figure, the external voltage is applied to the port 121a connected to the first metal line 121 and the external port 123a connected to the second metal line 123 through the external ports. Also, a predetermined DC (direct current) voltage is applied to the common electrode of the second substrate 200 . In this way, an A/P (automatic detection) test can be performed referring to step 44S in FIG. 7 .

The detection device 400, with the combined LC panel sandwiched between the first and second polarizers, together with the light from the light source 300 and the applied power, simulates the operation of an LC display assembly producing a solid-state image. Electrical faults such as opens or shorts on strobe and data lines are visually obvious because the areas will be blank (or have other distortions). In addition, image defects such as cross-band areas, black areas, color filter protrusions, slanted stripes, friction bands, pinholes, open or short circuits of gate lines and data lines can be detected by the observer or by the CCD (charge-coupled device) observed.

After the A/P test is completed, the detection device 400 is rotated back to the initial position (refer to step 45S). The LC panel is then placed in the box by the robot (see step 46S).

Beneficially, A/P testing is performed on the production assembly line, thereby preventing unnecessary delay and inconvenience.

Subsequently, an S/B (scribing/breaking) process is performed (see step 47S). The S/B process includes a scribing step of forming cut lines on the glass surface with a diamond-based pen and a cleaving step of cutting the glass by applying force. The S/B process divides a large LC panel into a plurality of unit LC panels called cell units.

Then, a grinding process is performed in step 45S to grind the surface of the cell LC panel, thereby completing the third step 700 .

Thereafter, an assembly process is performed in which a driver IC, a backlight source, and the like are mounted.

Therefore, the method for fabricating a liquid crystal display according to the present invention has the following advantages.

First, the electrode structure enables electrical and visual inspection of combined LC panels before each LC panel is obtained. This enables a single inspection that reduces inspection time and reduces worker fatigue. In addition, the present invention performs A/P testing in the early stage of production, so that fault information can be fed back and mass-produced products can be improved.

It will be obvious to those skilled in the art that various improvements and modifications can be made on the basis of the present invention. Thus, it is intended that the present invention covers the modifications and variations that come within the scope of the appended claims and their equivalents.

Claims (4)

1. A testing device, comprising: tiltable workbench; a light source disposed inside the workbench, said light source capable of emitting light; a first polarizer disposed on the combined liquid crystal display panel; a second polarizer disposed between the light source and the combined liquid crystal display panel; and At least two electrical ports located on the bench; where the workbench is sized to accept the liquid crystal panel; and Among them, the electrical port can provide predetermined voltage to the liquid crystal panel on the workbench. 2. The apparatus according to claim 1, further comprising a fixing seat for fitting the liquid crystal panel with the workbench. 3. The device according to claim 1, wherein the combined liquid crystal panel comprises a plurality of unit liquid crystal panel regions. 4. The apparatus of claim 3, wherein each cell panel area comprises: A TFT unit substrate area with a plurality of cross gate lines and data lines; a color filter substrate region including a black matrix layer, a color filter layer and a common electrode; and A liquid crystal layer disposed between the TFT and CF cell substrate regions.

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