KR100715937B1 - Method of manufacturing display device having the flexibility - Google Patents

Abstract

Disclosed is a method of manufacturing a flexible display device in which deformation of a plastic substrate does not occur. The above-described method is a lamination method of a plastic substrate for preventing deformation of the plastic substrate during the process of forming an image display element on the surface of the plastic substrate, and after preparing a carrier substrate having a first size, the second size is formed on the carrier substrate. Laminating at least two or more plastic substrates having a. This method can effectively prevent the change caused by the difference in the coefficient of thermal expansion between the plastic substrate and the carrier substrate, which is a flexible substrate, as well as increase the efficiency of the process.

Description

METHOOD OF MANUFACTURING DISPLAY DEVICE HAVING THE FLEXIBILITY

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the bending state of a plastic substrate by the difference of the thermal expansion rate of a plastic substrate and a glass substrate.

It is a figure which shows the bending state of a plastic substrate by the difference of the shrinkage ratio of a plastic substrate and a glass substrate.

3A to 3C are cross-sectional views illustrating a method of laminating a plastic substrate for manufacturing a flexible display device according to a first embodiment of the present invention.

4A to 4C are cross-sectional views illustrating a method of laminating a plastic substrate for manufacturing a flexible display device according to a second embodiment of the present invention.

5A to 5D are cross-sectional views illustrating a method of laminating a plastic substrate for manufacturing a flexible display device according to a third embodiment of the present invention.

6 is a process flowchart showing a method of manufacturing a flexible color filter substrate according to a fourth embodiment of the present invention.

7 is a process flowchart illustrating a method of manufacturing a flexible array substrate according to a fifth embodiment of the present invention.

* Explanation of symbols for main parts of drawings *                 

100, 200, 300: carrier substrate

150, 250, 350: first plastic substrate

160, 260, 360: second plastic substrate

B: adhesive material

The present invention relates to a method of manufacturing a flexible display device, and more particularly, to a method of manufacturing a flexible display device by laminating a plurality of plastic substrates so that deformation does not occur in the manufacturing process.

Recently, with the development of technology, the generalization of the Internet, and the amount of information communicated explosively, an ubiquitous display environment that can access information anytime and anywhere is being created. Therefore, the role of the display device, which is a medium for outputting information, becomes more important, its use range is becoming more widespread, and the demand for the display device is rapidly increasing.

Most of such display apparatuses have a structure including two planar substrates commonly made of rigid glass material and a layer of liquid crystal material arranged between the substrates. The glass substrates are separated by placing spacers of the same size between the glass substrates to maintain a slightly constant gap between the substrates. Moreover, an electrode means for generating an electric field through the liquid crystal material is provided. Through this, an optical change of the liquid crystal display device may be generated by applying a voltage to the electrode means, thereby changing the optical properties of the liquid crystal material disposed between the electrodes.

However, a problem with this kind of display device is that due to the glass substrate, the substrate is not only very hard and heavy, but also has a very low tolerance for bending stress. When the display device receives bending moments, a change in the cell gap between the two substrates causes a loss of the display image because a change in the thickness of the liquid crystal layer occurs.

In addition, in order to implement the above-described ubiquitous display environment, it is possible to improve the portability of a display device and to display various multimedia information, and to display a light, wide display area, high resolution, and high display speed. Characteristics must be required.

In order to meet these demands, in order to reduce the weight and size of the display apparatus, research has been actively conducted in the direction of reducing the density of the glass substrate and the thickness of the glass substrate constituting the display apparatus. However, when the glass density of the glass substrate applied to the display device, that is, the liquid crystal display panel, is reduced, the silicon substrate constituting the glass substrate (SiO ₂ ) substantially determines all physical property values of the glass substrate. The technique of lowering the hurdle is facing limitations.

Therefore, in order to simultaneously satisfy characteristics of excellent flexibility, light weight, and portability, a method of forming wirings and elements of a display device on a plastic substrate has emerged.

The roll-to-roll method is ultimately applied to the method of manufacturing the flexible display device by applying the above-described plastic substrate. However, in order to produce a flexible display device in the above-described manner, not only a dedicated facility for applying a plastic substrate in all processes of the production stage but also a large investment cost is required.

As a result, existing LCD makers such as Sharp and Philips are researching flexible display devices, but most of them have been researching a flexible display device by devising a dedicated chuck to apply a plastic substrate. It's going on. However, this research has the disadvantage that the current mass production equipment has to be changed drastically because the existing LCD mass production equipment cannot be used as it is.

In addition, a method of applying a plastic substrate to an LCD mass production facility by attaching the plastic substrate to a glass substrate coated with an adhesive has been proposed. However, unlike the glass substrate, the plastic substrate has a large thermal expansion and shrinkage characteristic. Have

For this reason, when the plastic substrate is applied to a high temperature TFT / LCD process in a state in which the plastic substrate is adhered to the glass substrate, the plastic substrate is bent toward the glass substrate 10 having a small thermal expansion as shown in FIG. 1 and left at room temperature in a high temperature process. As a result, as shown in FIG. 2, the shrinkage is bent toward the large plastic substrate 15.

That is, since the warping phenomenon of the plastic substrate increases greatly as the size of the plastic substrate increases, not only does the process of all processes including the exposure process for forming the display element become impossible, and even the glass substrate has a stress (stress). It can't stand and break. When such a problem occurs, not only the manufacturing of a flexible display device having a large screen is possible, but also the use of a large substrate even in a small and medium-sized product, the process yield and efficiency are drastically reduced.

Accordingly, an object of the present invention to solve the above problems is to prevent the bending of plastic substrates supported on the carrier substrate during the image display device forming process and to manufacture a flexible display device that can increase production efficiency under existing display production equipment. To provide a method.

According to an aspect of the present invention, there is provided a method of manufacturing a flexible display device, the method comprising: (a) providing a carrier substrate having a first size for supporting a plastic substrate during a wiring forming process of a display device; And (b) stacking at least two plastic substrates having a second size on the carrier substrate to mitigate deformation caused by difference in coefficient of thermal expansion with the carrier substrate during the wiring forming process of the display device.                     

In addition, a method of manufacturing a flexible display device according to another embodiment for realizing the above object, (a) the above on a carrier substrate having a first size for supporting a plurality of plastic substrates in the image display element forming process of the display device Stacking a plurality of plastic substrates having a second size to mitigate strain due to thermal expansion coefficient differences of the carrier substrate; (b) forming image display elements on the surfaces of the plurality of plastic substrates of step (a); And (c) separating the carrier substrate from the plurality of plastic substrates of step (b).

According to such a flexible display device manufacturing method, a plurality of plastic substrates having a smaller size than that of a carrier substrate are laminated on the carrier substrate to form an image display device, thereby providing a thermal expansion coefficient between the flexible substrate and the carrier substrate. By effectively alleviating the change caused by the difference of the plastic substrates to effectively prevent the warpage phenomenon, as well as manufacturing a plurality of flexible display devices on a single carrier substrate has the effect of increasing the manufacturing efficiency.

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

3A to 3C are cross-sectional views illustrating a method of laminating a plastic substrate for manufacturing a flexible display device according to a first embodiment of the present invention.

Referring to FIG. 3A, first, a carrier substrate 100 having a first size is prepared. Here, the carrier substrate 100 may be a glass substrate, a silicon substrate, a high heat resistant plastic substrate, or the like. The carrier substrate 100 of the first embodiment of the present invention is a glass substrate 100 having a size of 80 cm × 60 cm, and a glass substrate 100 having a wider size may be used.

Referring to FIG. 3B, plastic substrates 150 having a second size to be stacked on a glass substrate 100, which is a carrier substrate, are prepared. The plastic substrates 150 having the second size are plastic substrates 150 having a size of about 10 cm × 10 cm.

Here, the method of forming the plastic substrate 150 having the second size is to prepare a large plastic substrate, and then cut the plastic substrate by using a cutting device such as a laser or a rotary saw to reduce the size of tens to hundreds of 10 cm × 10 cm. The plastic substrate which has is formed.

Referring to FIG. 3C, 35 plastic substrates are formed on the top surface of the glass substrate 100 under a predetermined temperature after the adhesive material B is applied to the bottom surfaces of the 35 10 cm × 10 cm plastic substrates to have a uniform thickness. Are stacked so that they do not overlap each other. Although not shown in the drawings, the application of the adhesive material may be applied to the upper surface of the carrier substrate.

In this case, when the plastic substrate 150 coated with the adhesive material is attached onto the glass substrate 100, bubbles (air bubbles) should be attached so as not to be generated. When bubbles exist between the plastic substrates 150 and the glass substrate 100 to be attached, the adhesive force of the adhesive material is weakened at a process of about 150 ° C. to form an image display device. This is because the substrate 100 is separated from each other by floating.                     

When the 35 plastic substrates 150 are stacked on the glass substrate 100, the plastic substrates 150 may be disposed to be interviewed with each other, but may be spaced apart from each other. This is because it is necessary to take into account that each of the plastic substrates is thermally expanded and its length is increased in the formation process of the image display element. Thus, the separation distance of the plastic substrates must be equal to or greater than the length at which the plastic substrate is thermally expanded.

As described above, when a plurality of plastic substrates 150 having a size of 10 cm × 10 cm stacked on a glass substrate 100 having a size of 80 cm × 60 cm is stacked, the plastic substrate 150 is a glass substrate 100. Since the size is relatively small, the difference in thermal expansion rate change of the plastic substrate is very small in the process of forming the image display device.

This is because as the size of the plastic substrate is reduced, the dimensional stability of the plastic substrate is increased.

Accordingly, as the size of the plastic substrate is reduced, thermal expansion and thermal contraction change are minimally generated at the center of the plastic substrate, so that the warpage of the substrate is not large.

In addition, in the above-described method, since a plurality of plastic substrates are stacked on only one carrier substrate, a flexible display device corresponding to the number of plastic substrates can be formed when the image display element is formed in one cycle. The efficiency of the process can be maximized.                     

4A to 4C are cross-sectional views illustrating a method of laminating a plastic substrate for manufacturing a flexible display device according to a second embodiment of the present invention.

Referring to FIG. 4A, first, a carrier substrate 200 having a first size is prepared. Here, the carrier substrate 200 may be a glass substrate, a silicon substrate, a high heat resistant plastic substrate, or the like. The carrier substrate 200 according to the second embodiment of the present invention is a silicon substrate 200 having a size of 50 cm × 40 cm, and a silicon substrate 200 having a wider size may be used.

Referring to FIG. 4B, plastic substrates 250 having a second size to be stacked on the silicon substrate 200 are prepared. The plastic substrates 250 having the second size have a size of about 10 cm × 10 cm.

Here, in the method of forming the plastic substrate 250 having the second size, the plastic substrate 250 having the size of tens to hundreds of 10 cm × 10 cm is provided by cutting the plastic substrate using a cutting device after preparing a large plastic substrate. ) To form.

Referring to FIG. 4C, the adhesive material B is applied to the bottom of the twelve plastic substrates 250 having a size of 10 cm × 10 cm to have a uniform thickness, and then the upper surface of the silicon substrate 200 is formed under a predetermined temperature. The 12 plastic substrates are stacked without overlapping each other. Although not shown in the drawings, the application of the adhesive material may be applied to the upper surface of the silicon substrate.

In this case, when the plastic substrate 250 coated with the adhesive material is attached onto the silicon substrate, bubbles (air bubbles) should be attached so as not to be generated. Since the problem thereof has been described in detail in the first embodiment, it will be omitted.

In addition, when the 12 plastic substrates 250 are stacked on the silicon substrate 200, the plastic substrates 250 may be arranged to be interviewed with each other. However, the plastic substrates 250 may be spaced apart from each other. This is because the length of each of the plastic substrates to be thermally expanded should be considered in the process of forming the image display element performed at about 150 ° C.

As described above, when a plurality of plastic substrates 250 having a size of 10 cm × 10 cm are stacked on a silicon substrate 200 having a size of 50 cm × 40 cm, the plastic substrate 250 may be a silicon substrate 200. Since the size is relatively small, the difference in thermal expansion rate change of the plastic substrate is very small in the process of forming the image display device. This is because as the size of the plastic substrate is reduced, the dimensional stability of the plastic substrate is increased.

Accordingly, as the size of the plastic substrate is reduced, thermal expansion and thermal contraction change are minimally generated at the center of the plastic substrate, so that the warpage of the substrate is not large.

In addition, in the above-described method, since a plurality of plastic substrates are stacked on only one carrier substrate, a flexible display device corresponding to the number of plastic substrates can be formed when the image display element is formed in one cycle. The efficiency of the process can be maximized.

5A to 5D are cross-sectional views illustrating a method of laminating a plastic substrate for manufacturing a flexible display device according to a third embodiment of the present invention.

5A and 5B, a carrier substrate 300 having a first size is prepared first. Here, the carrier substrate 300 may be a glass substrate, a silicon substrate, a high heat resistant plastic substrate, or the like. The carrier substrate 300 of the first embodiment of the present invention is a glass substrate 300 having a size of 70 cm × 60 cm, and a glass substrate 300 having a wider size may be used.

Subsequently, the adhesive material B is applied to the top surface of the glass substrate 300 or the bottom surface of the plastic disc to have a uniform thickness, and then the plastic disc 340 is laminated on the glass substrate 300. Here, the plastic disc 340 is a substrate having a size of about 60 cm x 50 cm.

In this case, when the plastic disc 340 is attached to the glass substrate 300 to which the adhesive material B is applied, it should be attached to prevent bubbles (air bubbles) from being generated. Since this is described in detail in the first embodiment, it will be omitted to avoid duplication.

Referring to FIGS. 5C and 5D, 30 plastic substrates 350 having a second size are separated by performing a predetermined cutting process on the plastic disc 340. Here, the cutting process is performed by applying a laser beam, a rotary saw, etc., the plastic substrate 350 having the second size has a width of 10cm × 10cm.

Subsequently, the plastic substrate 350 is separated from each other so that the 30 substrates are spaced apart from each other. The distance that the plastic substrates 350 are spaced apart from each other corresponds to a length at which the plastic substrate is thermally expanded at a temperature of about 150 ° C.

As described above, when the plurality of plastic substrates 350 having a size of 10 cm × 10 cm stacked on the glass substrate 300 having a size of 70 cm × 60 cm is stacked, the plastic substrate 350 is a glass substrate 300. Since the size is relatively small, the difference in thermal expansion rate change of the plastic substrate is very small in the process of forming the image display device. This is because as the size of the plastic substrate is reduced, the dimensional stability of the plastic substrate is increased.

Therefore, as the size of the plastic substrate is reduced, thermal expansion and heat shrinkage change are minimally generated at the center of the plastic substrate, so that the warpage of the substrate is not large.

In addition, in the above-described method, since a plurality of plastic substrates are stacked on only one carrier substrate, a flexible display device corresponding to the number of plastic substrates can be formed when the image display element is formed in one cycle. The efficiency of the process can be maximized.

6 is a flowchart illustrating a method of manufacturing a flexible color filter substrate according to a fourth embodiment of the present invention.

Referring to FIG. 6, first, a first glass substrate, which is a carrier substrate having a first size, is prepared. Subsequently, a uniform thickness of a bonding material is applied to the first plastic substrates having a predetermined area or the second size of the first glass substrate, and then the plurality of first plastic substrates are formed on the carrier substrate under a predetermined temperature. Laminating sequentially (steps S110 and S120).

At this time, when attaching a 1st plastic substrate on a 1st glass substrate, it should attach so that a bubble (air bubble) may not generate | occur | produce. This is because when bubbles are introduced between the first plastic substrates and the first glass substrate, the adhesive force is weakened during the high temperature process of forming the patterns of the color filter substrate, causing the first glass substrate and the first plastic substrates to be lifted. . The size of the first glass substrate may be several times to several tens of times that of the first plastic substrate.

Subsequently, the first plastic substrates are spaced apart from each other so that the plurality of second plastic substrates are separated from each other (S130). Here, the distance at which the first plastic substrates are spaced apart from each other is such that the plastic substrate is thermally expanded at a temperature of about 150 ° C. Greater than the length

Subsequently, a color filter substrate in which the first plastic substrates are supported on the first glass substrate by forming a color filter, a black matrix, an overcoating layer, and a common electrode on each of the first plastic substrates attached on the first glass substrate. (Step S140).

Here, in detail the method of forming the color filter substrate, first, a color resin having a red color among red (R) / green (G) / blue (B) color resin is applied to the entire surface of the first plastic substrate on which the black matrix is formed. After selectively exposing, a red (R) color filter is formed in the display area. Randomly It will be explained in the order of red (R), green (G), and blue (B)). Subsequently, a green color resin is coated on the entire surface of the first plastic substrate on which the red color filter is formed, and then selectively exposed to form a green color filter. Subsequently, a blue (B) color resin is coated on the entire surface of the first plastic substrate on which the red (R) and green (G) color filters are formed, and then selectively exposed to form a blue color filter.

Subsequently, after forming an overcoating film for removing a step between the black matrix and the color filter, a common electrode is formed on the overcoating film corresponding to the color filter. In detail, first, a common electrode film having a predetermined thickness is continuously formed on the resultant. The common electrode layer is formed by depositing one selected from a group of transparent conductive materials including indium tin oxide (ITO) and indium zinc oxide (IZO). A common electrode is formed by etching an common electrode layer on the black matrix by applying an etching mask.

Subsequently, the first glass substrate is separated from the color filter substrate by impregnating the glass substrate supporting the color filter substrates with an organic solvent that dissolves the adhesive material (step S150). As a result, a flexible color filter substrate is formed.

7 is a process flowchart illustrating a method of manufacturing a flexible array substrate according to a fifth embodiment of the present invention.

Referring to FIG. 7, first, a second glass substrate, which is a carrier substrate having a first size, is prepared. Subsequently, a plurality of second plastic substrates may be formed on the carrier substrate under a predetermined temperature by applying a bonding material to the second plastic substrates having a predetermined area or second size with a uniform thickness. Laminating sequentially (steps S210 and S220).

At this time, when attaching a 2nd plastic substrate on a 2nd glass substrate, it should attach so that a bubble (air bubble) may not generate | occur | produce. Here, the size of the second glass substrate may be several times to several tens of times larger than that of the second plastic substrate.

Subsequently, the second plastic substrates are spaced apart from each other such that the plurality of second plastic substrates are separated from each other (S230). Here, the distance from which the second plastic substrates are spaced apart from each other is a length at which the plastic substrate is thermally expanded at a temperature of about 150 ° C. Greater than

A second plastic supported on the second glass substrate by forming a thin film transistor, a gate insulating film, a passivation film, an organic film, and a pixel electrode on each of the second plastic substrates attached on the second glass substrate. The substrates are formed into array substrates (step S240).

The method of forming the array substrate will be described in detail. A conductive material is deposited on the second plastic substrate. Subsequently, a portion of the conductive material is etched to form the gate electrode. Thereafter, a gate insulating film is deposited on the entire surface of the second plastic substrate on which the gate electrode is formed. The gate insulating film is formed of a silicon nitride film (SiNx) that is a transparent insulating material.

Subsequently, amorphous silicon and N + amorphous silicon are deposited and etched to form a semiconductor layer on the gate insulating film corresponding to the gate electrode. Subsequently, a source electrode and a drain electrode are formed by depositing a conductive material on the gate insulating layer on which the semiconductor layer is formed, and then etching a portion of the conductive material.                     

Subsequently, a transparent insulating material is deposited on the second plastic substrate on which the thin film transistor is formed to form a passivation film, and then a portion of the passivation film is removed to form an opening exposing a portion of the drain electrode. In this case, the opening may be formed after forming the organic layer.

Subsequently, an organic material is applied onto the passivation film to form an organic film. The organic material includes a photoresist component. Thereafter, the organic film is exposed and developed to form an organic film in which a part of the drain electrode is opened.

Subsequently, ITO, IZO, ZO, and the like, which are transparent conductive materials, are deposited on the organic layer and the passivation layer, and a portion of the transparent conductive material is etched to form pixel electrodes in the pixel region.

Subsequently, the second glass substrate supporting the array substrates is impregnated with an organic solvent for dissolving the adhesive material to separate the second glass substrate from the array substrate (step S250). As a result, a flexible array substrate is formed.

As described above, the method of manufacturing the flexible display device of the present invention performs a high temperature chemical vapor deposition process of forming a plurality of plastic substrates having a smaller size than the carrier substrate on the carrier substrate and forming wirings of the image display device. In addition, the difference in thermal expansion coefficient between the plastic substrate and the carrier substrate can be minimized, and the efficiency of the unit process for forming the display device can be increased.                     

In addition, it can be applied to the production line of the existing display device without changing the equipment to form a flexible display device without the equipment investment of the mass production equipment, and also the display element forming process under the state that a plurality of plastic substrates are stacked on the carrier substrate As a result, the efficiency of the process can be maximized.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (14)

(a) providing a carrier substrate having a first size for supporting a plastic substrate in a wiring forming process of a display device; And (b) stacking at least two plastic substrates having a second size smaller than the first size on the carrier substrate such that deformation due to a difference in thermal expansion coefficient with the carrier substrate is alleviated during the wiring forming process of the display device; Method of manufacturing a flexible display device comprising a. delete The method of claim 1, further comprising, after step (a), applying an adhesive material to the surface of the carrier substrate or the bottom surface of the plastic substrate. The method of claim 1, wherein in the step (b), the plastic substrates are stacked apart from each other. The method of claim 4, wherein the separation distance of the plastic substrates is greater than a thermally expanded length of the plastic substrates. The method of claim 1, wherein the carrier substrate is any one selected from the group consisting of a glass substrate, a silicon substrate, and a high heat resistant plastic substrate. The method of claim 1, wherein the laminating method of the plastic substrate of step (b), Attaching a plastic disc smaller than the first size and larger than the second size; And Cutting the plastic disc to form plastic substrates having the second size. (a) a material smaller than the first size on the carrier substrate having a first size for supporting a plurality of plastic substrates in the process of forming an image display element of the display device such that deformation due to thermal expansion coefficient difference with the carrier substrate is alleviated; Stacking a plurality of plastic substrates having two sizes; (b) forming an image display device on a surface of the plastic substrates; And (c) separating the carrier substrate from the plastic substrates. delete The method of claim 8, wherein in the step (a), the plastic substrates are stacked apart from each other. The method of claim 10, wherein the separation distance of the plastic substrates is greater than a thermally expanded length of the plastic substrates. The method of claim 8, wherein the carrier substrate is any one selected from the group consisting of a glass substrate, a silicon substrate, and a high heat resistant plastic substrate. The display device of claim 8, wherein the image display device comprises a thin film transistor, A method of manufacturing a flexible display device, which is defined as a thin film transistor substrate by step (b). The display device of claim 8, wherein the image display device comprises a color pixel layer, The method of manufacturing a flexible display device, characterized in that the step (b) is defined as a color filter substrate.

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