KR20110013917A

KR20110013917A - Ink-jet printing apparatus and ink-jet printing method

Info

Publication number: KR20110013917A
Application number: KR1020090071624A
Authority: KR
Inventors: 서황운; 정택준
Original assignee: 엘지디스플레이 주식회사
Priority date: 2009-08-04
Filing date: 2009-08-04
Publication date: 2011-02-10

Abstract

PURPOSE: Inkjet printing apparatus and method are provided to significantly enhance the yield of substrates since the process parameter of a mother board is determined using a separate recyclable test substrate. CONSTITUTION: An inkjet printing apparatus comprises a gantry unit(100), an auxiliary process unit(300), a main process unit(200) and a controller(400). A plurality of inkjet heads for the materials of R, G, B color filters, and a camera are movably installed along an x-axis on the gantry unit. The auxiliary process unit is added under the gantry unit in a test process and comprises a test substrate and a backlight unit. While being transferred along a y-axis, which crosses the x-axis, the test substrate receives a color filter for test based on the test parameter. The backlight unit is arranged under the test substrate. The main process unit is added under the gantry unit in the main process. The controller controls the discharging of the inkjet head using the test parameter.

Description

Inkjet Printing Device and Printing Method {INK-JET PRINTING APPARATUS AND INK-JET PRINTING METHOD}

The present invention relates to an inkjet printing apparatus and a printing method used in a color filter process of a liquid crystal display device.

In today's information society, display devices are more important than ever as visual information transfer media. Cathode ray tubes or CRT tubes, which were once mainstream, had problems with weight and volume. In order to overcome the limitations of the cathode ray tube, many kinds of flat panel displays have been developed.

Flat panel displays include Liquid Crystal Display (LCD), Field Emission Display (FED), Plasma Display Panel (PDP) and Electro-luminescence (EL). And most of them are commercially available and commercially available.

Among them, the liquid crystal display device displays a desired image on the screen by adjusting the transmission amount of the light beam according to the image signal applied to the plurality of control switches arranged in a matrix form, and is characterized by light weight, thinness, and low power consumption. As a result, its application range is expanding. In accordance with this trend, liquid crystal displays are widely used in portable computers such as notebook PCs, office automation equipment, audio / video equipment, indoor and outdoor advertising displays, navigation devices, rear detectors, and the like.

As shown in FIG. 1, the liquid crystal display includes a color filter array substrate 10 and a thin film transistor array substrate 20 bonded to each other with the liquid crystal layer 16 therebetween.

The color filter array substrate 10 may form an electric field with the black matrix 13 for preventing light leakage stacked on the upper glass substrate 11, the color filter unit 12 for implementing color, and the pixel electrode 25. Common electrode 14 and an upper alignment layer coated for liquid crystal alignment.

The thin film transistor array substrate 20 includes a gate line 23 and a data line 24 formed to intersect with each other stacked on the lower glass substrate 21, and a thin film transistor 26 formed at an intersection of the 23 and 24. ), A pixel electrode 25 connected to the thin film transistor 26, and a lower alignment layer coated for liquid crystal alignment.

In the liquid crystal display device having such a structure, the color filter unit includes R (red), G (green), and B (blue) color filters. R, G, and B color filters are partitioned by a black matrix. Electrodeposition, pigment dispersion, and printing are known as methods for forming R, G, and B color filters, and inkjet printing has been widely used in recent years.

The inkjet printing method uses a plurality of inkjet heads to form R, G and B color filters by dropping three primary color inks into each sub-pixel area separated by a black matrix. The inkjet printing method has many advantages in terms of simplification of the process and reduction of manufacturing cost compared to the pigment dispersion method. However, since the internal flow path structure of the inkjet heads is very complicated, it is difficult to keep the ink discharge amount of all the heads constant in the inkjet printing method. If the ink discharge amount between the heads is non-uniform, the coating thicknesses of the R, G, and B color filters are different from each other, resulting in unsatisfactory defects. Since the substrate on which stain has been generated is disposed of, the substrate yield is low in the inkjet printing method.

Accordingly, an object of the present invention is to provide an inkjet printing apparatus and a printing method for improving the yield of the substrate while improving the defect defects due to the difference in the coating thickness of the color filter.

In order to achieve the above object, an inkjet printing apparatus according to an embodiment of the present invention is a gantry unit installed a plurality of inkjet heads for spraying the R, G, B color filter material, and the camera is linearly movable along the x-axis ; In the test process, a test substrate which is put under the gantry unit and is transferred along the y-axis intersecting the x-axis and is coated with a test color filter based on a test parameter value, and an auxiliary including a backlight unit disposed below the test substrate. Processing equipment; A main processing apparatus including a mother substrate which is applied under the gantry unit during the main processing and then is transported along the y-axis and coated with a color filter based on process parameter values; And controlling the ejection of the inkjet head by using the test parameter value, and determining the transmittance of the test color filter according to the image photographed by the camera, wherein the test parameter value when the transmittance satisfies a preset reference value. It is provided with a control unit for determining the as the process parameter value.

The printing apparatus includes an inkjet head driver for driving the inkjet heads; And a memory for storing the process parameter values.

The inkjet head driver is configured to drive the inkjet heads according to the test parameter values to supply the R, G, and B color filter materials onto the test substrate; The inkjet heads are driven according to the process parameter values to supply the R, G, and B color filter materials onto the mother substrate.

The auxiliary processing apparatus further includes a cleaning device for removing the test color filter from the test substrate.

The test substrate has a size of 1/6 to 1/5 of the mother substrate.

The test parameter value and the process parameter value indicate nozzle voltages applied to the nozzles of the inkjet heads, respectively.

In addition, according to an embodiment of the present invention, the inkjet printing method using a plurality of inkjet heads for ejecting the R, G, B color filter material, and a gantry unit in which the camera is linearly movable along the x-axis is provided. Applying a test color filter to the test substrate on the basis of test parameter values while feeding the gantry unit under the gantry unit and transferring it along the y axis crossing the x axis; The transmittance of the test color filter is determined according to the image photographed by the camera while the backlight unit under the test substrate is turned on, and the test parameter value when the transmittance satisfies a preset reference value is a process parameter value. Determining as; And applying a color filter to the mother substrate based on the process parameter values while feeding the mother substrate under the gantry unit and transferring it along the y axis.

The inkjet printing apparatus and the printing method according to the present invention, before applying the RGB color filter to the mother substrate, by using a separate test substrate that is much smaller than the mother substrate to determine the process parameter value of the mother substrate, the color formed on the mother substrate By making the coating thickness of the filter uniform, it is possible to greatly improve unstained defects as in the prior art.

Furthermore, the inkjet printing apparatus and the printing method according to the present invention determine the process parameter value of the mother substrate by using a separate reusable test substrate, thereby greatly reducing the amount of substrate consumed in the test process and greatly improving the substrate yield. have.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 2 to 6.

2 schematically shows an inkjet printing apparatus according to an embodiment of the present invention. 3 and 4 are principle diagrams for explaining the test process, and FIG. 5 is a principle diagram for explaining the main process.

2 to 5, the inkjet printing apparatus according to the present invention includes a gantry unit 100, a main processing apparatus 200, an auxiliary processing apparatus 300, a controller 400, and a memory 500. .

The gantry unit 100 includes a first gantry 110 and a second gantry 120 as shown in FIG. 2.

One side of the first gantry 110 is provided with at least one R inkjet head 130R for injecting a color filter material of a first color (hereinafter, “R”), and the other of the first gantry 110. At least one G inkjet head 130G for ejecting the color filter material of the second color (hereinafter, "G") is provided on the side. The R and G inkjet heads 130R and 130G include jet nozzles and are connected to a supply device (not shown) containing R and G color filter materials, respectively. The first gantry 110 is further provided with linear moving means 150 for linearly moving the R and G inkjet heads 130R and 130G in the (+) x-axis direction or the (-) x-axis direction, respectively.

At least one B inkjet head 130B for spraying a color filter material of a third color (hereinafter, “B”) is installed at one side of the second gantry 120, and the other of the second gantry 120 is provided. On the side, a camera 140 for photographing the test RGB color filter is installed. The B inkjet head 130B includes a jet nozzle and is connected to a supply device (not shown) containing B color filter material. The second gantry 120 is further provided with linear moving means 150 for linearly moving the B inkjet head 130B and the camera 14 in the positive (+) x-axis direction or the negative (-) x-axis direction, respectively.

The R, G, and B inkjet heads 130R, 130G, and 130B are connected to the inkjet head driver 160 as shown in FIGS. 3 and 5. The inkjet head driver 160 drives the R, G, and B inkjet heads 130R, 130G, and 130B based on the parameter values applied from the controller 400, and thus the R, G, and B inkjet heads 130R, 130G, and 130B are used. R, G, and B color filter materials are discharged from the tube. Here, the parameter values indicate the nozzle voltages applied to the nozzles of the R, G, and B inkjet heads 130R, 130G, and 130B to control the ink discharge amount or the discharge time.

The camera 140 is connected to the camera driver 170 as shown in FIGS. 3 and 5. The camera driver 170 drives the camera 140 when the backlight unit 330 of the auxiliary processing apparatus 300 is turned on under the control of the controller 400, and controls the image information obtained from the camera 140. 400). The image information is used to determine process parameters of the mother substrate 210.

As shown in FIG. 2, the auxiliary process apparatus 300 may include a test substrate 310 on which a test RGB color filter 315 is to be formed, an auxiliary stage 320 on which the test substrate 310 is mounted, and an auxiliary stage 320. And a straight line transfer means (not shown) for linearly moving along the y-axis intersecting with and the backlight unit 330 mounted under the auxiliary stage 320 to irradiate light to the test substrate 310.

In the test process step for determining the process parameters of the mother substrate 210, the auxiliary processing apparatus 300 is moved along the (-) y direction under the control of the control unit 400 as shown in FIG. Is placed underneath. As such, after the auxiliary processing apparatus 300 is disposed to move down the gantry unit 100, the auxiliary stage 320 is moved in the positive y-axis direction or the negative y-axis direction through the linear transport means. . In addition, the R, G, and B inkjet heads 130R, 130G, and 130B move in the positive (+) x-axis direction or the negative (-) x-axis direction in conjunction with the movement of the auxiliary stage 320, respectively. And B color filter material is sprayed onto the test substrate 310. In this case, the inkjet head driver 160 drives the R, G, and B inkjet heads 130R, 130G, and 130B based on test parameter values applied from the controller 400. As a result, a test RGB color filter 315 according to the test parameter value is formed on the test substrate 310. When the formation of the test RGB color filter 315 is completed, the backlight unit 330 is turned on under the control of the controller to irradiate light onto the back surface of the test substrate 310. In this state, the camera 140 photographs a test RGB color filter. The photographed image information is supplied to the controller 400.

Meanwhile, the auxiliary processing apparatus 300 further includes a cleaning apparatus 340 for washing the test RGB color filter 315 from the test substrate 310. When the transmittance of the test RGB color filter 315 according to the test parameter value does not satisfy the reference value, the cleaning device 340 sprays a solvent on the test substrate 310 as shown in FIG. 4 under the control of the controller 400. The previously formed test RGB color filter 315 is removed. As the test substrate 310 of the present invention, a quartz substrate patterned with a black matrix may be used. Thus, the life of the test substrate 310 is semi permanent. The size of the test substrate 310 is about 1/6 to 1/5 of the mother substrate 210, which is much smaller than that of the mother substrate 210, thereby facilitating a cleaning process for reuse. Applicant has proposed a technique for measuring the transmittance of the RGB color filter applied to the mother substrate and adjusting the injection amount of the problem inkjet head through the previously filed application No. 10-2008-130931. The present invention is much more advantageous in terms of substrate yield than this technique. Since the prior art forms an RGB color filter for test directly on the mother substrate, the mother substrate used in the test process should be discarded when the transmittance of the RGB color filter is different from the preset value, but the present invention is a reusable test substrate 310 Since the test process proceeds to), it is not necessary to discard the mother substrate 210 at all. The test RGB color filter is formed on the test substrate 310 from which the test RGB color filter 315 is removed through the above-described operation process based on the adjusted test parameter value. The camera 140 is also photographed for the test RGB color filter. If the transmittance of the test RGB color filter according to the adjusted test parameter value is not satisfied with the reference value, the cleaning process is performed for the test RGB color filter. Is done. This process is repeated until the transmittance of the test RGB color filter satisfies the reference value.

When the transmittance of the test RGB color filter satisfies the reference value, the auxiliary process apparatus 300 is moved along the (+) y direction under the control of the controller 400 and positioned on one side of the gantry unit 100 as shown in FIG. 5. do. As a result, the test process step is completed, and the test parameter value when the transmittance of the test RGB color filter satisfies the reference value is determined as the process parameter value of the mother substrate 210.

As shown in FIG. 2, the main process apparatus 200 linearly lines the mother substrate 210 on which the RGB color filter 215 is to be formed, the main stage 220 on which the mother substrate 210 is seated, and the main stage 220 along the y axis. It includes a linear transport means (not shown) for moving.

In the test process step, the main process apparatus 200 is moved along the (-) y direction under the control of the control unit 400 as shown in FIG. 3 and is located on one side of the gantry unit 100. After the test process step is completed, the main process step moves along the (+) y direction under the control of the control unit 400 as shown in FIG. 5 and is disposed below the gantry unit 100. Thus, after the main processing apparatus 200 is disposed to move down the gantry unit 100, the main stage 220 is moved in the positive (+) y-axis direction or (-) y-axis direction through the linear transport means do. In conjunction with the movement of the main stage 220, the R, G, and B inkjet heads 130R, 130G, and 130B move in the positive (+) x-axis direction or the negative (-) x-axis direction, respectively. And B color filter material is sprayed onto the mother substrate 210. In this case, the inkjet head driver 160 drives the R, G, and B inkjet heads 130R, 130G, and 130B based on the process parameter values of the mother substrate 210 determined in the test process step. As a result, a good RGB color filter 215 is formed on the mother substrate 210 without any defects.

The controller 400 generates a first control signal Cm to control the movement of the main process apparatus 200, and generates a second control signal Ca to control the movement of the auxiliary process apparatus 300. The controller 400 generates a third control signal Cb to control the driving of the backlight unit 330, and generates a fourth control signal Cs to control the driving of the cleaning device 340. In addition, the controller 400 determines the transmittance of the test RGB color filter based on the image information supplied from the camera driver 170, and determines the transmittance of the mother substrate 210 as a parameter value when the transmittance satisfies a preset reference value. Determine process parameter values.

The memory 500 stores the process parameter values of the mother substrate 210 and outputs them under the control of the controller 400.

6 sequentially shows an inkjet printing method according to an embodiment of the present invention.

Referring to FIG. 6, the inkjet printing method according to the present invention applies a test RGB color filter to a test substrate with test parameter values after the test substrate is placed under the gantry unit. (S1, S2)

When the application of the test RGB color filter is completed, the inkjet printing method turns on the backlight unit under the test substrate, and then uses the image information of the test RGB color filter taken by the camera to determine the transmittance of the test RGB color filter. (S3, S4)

The inkjet printing method compares the transmittance of the test RGB color filter with a predetermined reference value to determine whether the transmittance of the test RGB color filter satisfies the reference value (S5, S6).

In the inkjet printing method, when the transmittance of the test RGB color filter satisfies the reference value as a result of the determination in S6, after determining the process parameter value of the mother substrate using the test parameter value, the parameter value is stored in the memory (S7).

In the inkjet printing method, after the process parameter value of the mother substrate is determined, the test substrate is moved to one side of the gantry unit, and then the mother substrate is put under the gantry unit. (S8) Next, the inkjet printing method stores the stored parameter value. The RGB color filter is applied to the mother substrate. (S9)

On the other hand, in the inkjet printing method, when the transmittance of the test RGB color filter does not satisfy the reference value as a result of the determination of S6, a solvent is removed by spraying the test RGB color filter formed on the test substrate. After adjusting the value (S11), repeat steps S1 to S6.

As described above, the inkjet printing apparatus and the printing method according to the present invention determine the process parameter value of the mother substrate by using a separate test substrate which is much smaller than the mother substrate before applying the RGB color filter to the mother substrate. By making the coating thickness of the color filter formed on the substrate uniform, it is possible to greatly improve uneven stain as in the prior art.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1 is a perspective view showing a part of a general liquid crystal display device.

2 is a view schematically showing an inkjet printing apparatus according to an embodiment of the present invention.

3 and 4 are principle diagrams for explaining the test process.

5 is a principle diagram for explaining a main process.

6 is a flowchart sequentially showing an inkjet printing method according to an embodiment of the present invention.

100: gantry unit 200: main processing equipment

300: auxiliary process unit 400: control unit

500: memory

Claims

A gantry unit in which a plurality of inkjet heads for ejecting R, G, and B color filter materials, and a camera are installed to be linearly movable along the x axis;

In the test process, a test substrate which is put under the gantry unit and is transferred along the y-axis intersecting the x-axis and is coated with a test color filter based on a test parameter value, and an auxiliary including a backlight unit disposed below the test substrate. Processing equipment;

A main processing apparatus including a mother substrate which is applied under the gantry unit during the main processing and then is transported along the y-axis and coated with a color filter based on process parameter values; And

The discharge of the inkjet head is controlled using the test parameter value, the transmittance of the test color filter is determined according to the image photographed by the camera, and the test parameter value when the transmittance satisfies a preset reference value is determined. And a control unit for determining the process parameter value.

The method of claim 1,

An inkjet head driver for driving the inkjet heads; And

And a memory for storing the process parameter values.

The method of claim 2,

The inkjet head drive unit,

Driving the inkjet heads according to the test parameter values to supply the R, G, and B color filter materials onto the test substrate;

And driving the inkjet heads according to the process parameter values to supply the R, G, and B color filter materials onto the mother substrate.

The method of claim 1,

And the auxiliary processing apparatus further comprises a cleaning device for removing the test color filter from the test substrate.

The method of claim 1,

The test substrate is an inkjet printing apparatus, characterized in that having a size of 1/6 ~ 1/5 compared to the mother substrate.

The method of claim 1,

And the test parameter value and the process parameter value respectively indicate nozzle voltages applied to the nozzles of the inkjet heads.

In the inkjet printing method using a plurality of inkjet heads for ejecting the R, G, B color filter material, and a gantry unit in which the camera is linearly movable along the x axis,

Applying a test color filter to the test substrate based on a test parameter value while feeding a test substrate under the gantry unit and transferring it along the y-axis intersecting the x-axis;

The transmittance of the test color filter is determined according to the image photographed by the camera while the backlight unit under the test substrate is turned on, and the test parameter value when the transmittance satisfies a preset reference value is a process parameter value. Determining as; And

And applying a color filter to the mother substrate based on the process parameter value while feeding the mother substrate under the gantry unit and transferring it along the y axis.

The method of claim 7, wherein

And storing the process parameter values.

The method of claim 7, wherein

Removing the test color filter applied to the test substrate when the transmittance does not satisfy the reference value; And

Inkjet printing method further comprising the step of adjusting the test parameter value.

The method of claim 7, wherein