TWI449993B - Method for fabricating a display and the display produced therefrom - Google Patents

Description

Display manufacturing method and display thereof

The present invention relates to a method of manufacturing a display and a display thereof, and more particularly to a method of manufacturing a flexible display capable of improving the flatness of a display medium in a process and a display manufactured thereby.

In recent years, thin displays, such as liquid crystal displays, electronic paper, or e-books, are booming. The liquid crystal display having a single-layer liquid crystal structure, as shown in FIG. 1 , may include a lower substrate 2 , an upper substrate 4 , a plurality of liquid crystal materials 6 , a plurality of retaining walls 8 for separating the liquid crystal material, an upper cover 10 , and a first A conductive film 12 and a second conductive film 14.

However, as shown in FIG. 2, at the time of fabricating, for example, the aforementioned liquid crystal display, since the display medium material (liquid crystal) 9 and the materials of the substrate 3 or the retaining wall 7 have differences in chemical affinity and the like, the display medium material 9 The tendency to adhere to the retaining wall 7 causes the display medium material 9 sprayed on the surface of the substrate 3 to have a disadvantage of surface flatness and poor spray shape. Therefore, subsequent literature studies such as Microelectronic Engineering 82 (2005), pp 1-11, attempted to improve this problem with a double-layered photosensitive material, but the problem of flatness could not be completely solved, and the conventional technique was applied to a two-layer structure. The field of photosensitive materials all have the same shortcomings, as listed below: (1) The more complicated process, the current method of making a double-layered structural bank is to perform two coating or bonding processes, and then perform two exposures. The developing etching operation can obtain the substrate with the double-layer structure retaining wall; (2) or using the surface plasma treatment to make the surface of the retaining wall having only one layer structure have different characteristics, thereby producing the effect of a double-layer structural retaining wall, but The use of plasma surface treatment has many disadvantages, such as the need for expensive machines such as vacuum devices and plasma generation systems, the generation of toxic gases in the process that do not comply with environmental regulations, and the surface properties produced by surface treatment are only Temporary, and the plasma process can only be a single piece of the batch process, the output is slow and so on; and (3) the current double-layer structure retaining wall is not effective Problems of poor flatness of the dielectric material must display manufacturing process.

In view of the above, the present invention provides a method of manufacturing a display and a display manufactured thereby, which utilizes a relatively simple and environmentally friendly process to improve the flatness of the display medium after filling in the process.

In order to achieve the above and other objects, the present invention provides a method of manufacturing a display, comprising the steps of: providing a substrate having a first conductive layer; forming a plurality of retaining walls on the lower substrate; filling the display medium material Forming an upper cover on the display medium material; and performing a bonding process of the second conductive layer and the lower substrate, wherein the retaining walls are formed by forming a dry film on the lower substrate; A photomask is disposed over the dry film; and the dry film is patterned by a single photolithography process to form a plurality of barrier walls, wherein the dry film has at least two photoresist layers.

The present invention also proposes a display formed by the aforementioned method.

3A to 3E are schematic views of a preferred embodiment of a display device of the present invention. As shown in FIG. 3A, a substrate 16 is first provided, which has a first conductive layer 18 thereon. The lower substrate 16 can be a glass substrate or a plastic substrate and can include active or passive drive circuits. The type of resin that can be used for the plastic substrate can be, for example but not limited to, a polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (polyethylene naphthalate). , PEN); polyacrylate resin, such as polymethyl methacrylate (PMMA); polyolefin resin, such as polyethylene (PE) or polypropylene (PP); poly ring Polycycloolefin resin; polyimide resin; polycarbonate resin; polyurethane resin; triacetyl cellulose (TAC); Polylactic acid, or a combination thereof. It is preferably a polyester resin, a polycarbonate resin or a combination thereof. The first conductive layer 18 may be composed of materials well known to those skilled in the art, such as indium tin oxide (ITO), and may be formed on the lower substrate 16 by sputtering. . In addition, if the display medium material used is a liquid crystal material, an alignment layer (not shown) may be coated on the first conductive layer 18. The alignment layer may comprise polyvinyl alcohol, polyamidamine, polyamine, nylon, cerium oxide, and lecithin.

As shown in FIG. 3B, a dry film 20 is applied to the substrate 16 under the first conductive layer 18. In the preferred embodiment, the dry film 20 has a two-layer structure, which is an upper photoresist layer 20a and The lower photoresist layer 20b, however, the preferred embodiment is for illustrative purposes only, and is not intended to limit the number of layers included in the dry film 20. The number of layers of the dry film 20 can be changed to three layers according to practical applications. the above. In a preferred embodiment, the dry film 20 having a two-layer structure is formed on the lower substrate 16 by a lamination roller process. In another preferred embodiment, the dry film 20 having a two-layer structure is formed on the lower substrate 16 by a vacuum lamination process. For example, in the case of a two-layer dry film, the dry film (upper photoresist layer + lower photoresist layer) may have a thickness of about 5 to 50 μm, preferably 10 to 35 μm. In order to obtain a better planarization effect, the thickness of the lower photoresist layer should be controlled to be about the same as the thickness of the display dielectric material filled between the barrier structures. The dry film is a photosensitive material comprising a photosensitive resin and a surface modifying agent, and the dry film of the two-layer structure is composed of two different photosensitive materials, in other words, the photosensitive resin of the upper and lower photoresist layers. They may be the same or different, but different surface modifying agents must be used. The above photosensitive resins are suitable for those skilled in the art to which the present invention pertains, and may be acrylic type resins or Epoxy resin. The surface modifying agent may be wax, silane, for example, vinyl silane, polyether-functional trimethoxysilane, volsol novalac hybrid resin, Perfluorobutane sulfonate, for example, di-functional perfluorobutane sulfonate or silicone, for example, di-functional acrylic Type silicone), multi-functional acrylic type silicone, polyether silicone, perfluoropolyether silicone, di-functional isocyanate type silicone ), a di-functional amino type silicone. However, in the double-layer structure, the upper photoresist layer and the lower photoresist layer respectively have different chemical affinity, and the thicknesses of the upper photoresist layer and the lower photoresist layer are adjusted according to the thickness of the display medium material filling. To meet the needs of displays with a variety of different display modes. The affinity between the upper and lower photosensitive materials and various display medium materials is related to the surface tension, and can be judged by the contact angle between the photosensitive material and the display medium material. Generally, the contact angle is large, indicating that it is more repulsive (- Phob) shows the material of the medium, and the contact angle is small, indicating that it is a philic display medium material. Therefore, depending on the display medium used, the photosensitive material suitable for the upper photoresist layer and the lower photoresist layer can be arbitrarily matched. Generally, the photosensitive material of the upper photoresist layer is preferably composed of a material which is relatively more repellent to the display medium material, and the photosensitive material of the lower photoresist layer is preferably composed of a material of a relatively comparative display medium material. However, if the affinity between the photosensitive material of the lower photoresist layer and the display medium material is too large, the display medium material is adsorbed to both sides of the retaining wall and the surface is concave. Therefore, according to a preferred embodiment of the present invention, the display medium When the material is a cholesteric liquid crystal, the contact angle of the lower photoresist layer and the display medium material is about 30 degrees to about 45 degrees, which has a better planarization effect on the display medium material.

The experimental data in Table 1 below is based on cholesteric liquid crystal (RGB three colors) as the display medium material, and the contact angles of the photosensitive material against water and cholesteric liquid crystal (RGB three colors) are respectively measured to indicate the surface tension of the photosensitive material. characteristic. The source of the three-color cholesteric liquid crystal is Yongri Chemical Co., Ltd., and since the surface tension of various display medium materials is different, the present invention proposes that the contact angle of water is used as a reference point for reference. The 14 photosensitive materials listed in Table 1 can be constructed with a multilayer structure of a dry film in any thickness and combination. The main components of the 14 kinds of photosensitive materials include a photosensitive resin and a surface modifying agent, and the photosensitive resin may be a general organic photosensitive resin or an organic photosensitive resin having a special structure, such as an acrylic resin or an epoxy resin. The surface modifier includes paraffin, decane, Novalac phenolic resin, fluorine sulfonate and silicone. The contact angle of the photosensitive material to the display medium can be adjusted by using different photosensitive resins in combination with a suitable surface modifier.

In addition, the thickness of the upper layer above the dry film can also be adjusted to make the display medium material flat. For example, when the thickness of the photoresist layer under the dry film is equivalent to the thickness of the filled display medium material, the display medium material is easily leveled inside the groove, and the dielectric material of the photoresist layer on the thicker dry film is reused. The surface characteristics are such that the display medium material adsorbed to the two side walls is repelled, so that a display substrate which can make the surface of the display medium material flat is obtained. In a preferred embodiment, when the thickness of the groove of the display medium filled between the retaining walls is about 2 micrometers, the thickness of the photoresist layer on the dry film is about 3 micrometers to 33 micrometers, and the dry film is The thickness of the lower photoresist layer is about 2 micrometers. In another preferred embodiment, when the thickness of the recess of the display dielectric material between the barrier walls is about 5 micrometers, the thickness of the photoresist layer on the dry film is about 5 microns to 45 microns, and the thickness of the photoresist layer below the dry film is about 5 microns.

As shown in Figures 3B through 3C, the dry film 20 is then patterned. First, a photomask 22 is disposed above the dry film 20, and then a photolithography etching process is performed by the photomask 22, and a plurality of retaining walls 24 are simultaneously formed in the dry film 20 by a microlithography etching process (the recesses between the retaining walls are formed by grooves) 26 spaces), and the retaining wall has upper and lower layers 24a and 24b. Wherein, the thickness of the retaining wall is about 5 micrometers to 50 micrometers, preferably 10 to 35 micrometers, and the width of the retaining wall is about 15 micrometers to about 60 micrometers. However, the above specifications may be changed according to actual needs. Each of the retaining walls constitutes a pixel area of the display panel, and the distance between the retaining walls is about 50 micrometers to 250 micrometers, preferably about 70 micrometers to 100 micrometers. However, the above specifications can be changed according to actual needs.

After the above process is completed, after the plurality of retaining walls 24 and the plurality of grooves 26 are defined, the retaining wall 24 is solidified. The manner of curing is well known to those of ordinary skill in the art to which the present invention pertains, and may be used, for example, to include ultraviolet light curing. After curing, the substrate having the retaining wall 24 can be subjected to a subsequent baking process, using a temperature of about 100 ° C to 150 ° C, preferably about 100 ° C to about 120 ° C, for about 30 to 90 minutes, preferably about 40. Baking to 60 minutes to increase the chemical resistance and mechanical strength of the retaining wall 24.

As shown in FIG. 3D, the display medium material is filled between the barrier walls of the lower substrate 16 (i.e., in the recesses 26). The display medium material may be subjected to an ink-jet printing process by the ink-jet head 28, or may be filled between the barrier walls (in the recess 26) by vacuum input. The display medium material can be, for example, a cholesteric liquid crystal, or other display medium material well known in the art.

According to the dry film of the manufacturing example 1 to the manufacturing example 14 provided in Table 1, after curing, a plurality of retaining walls of a single layer or a double layer are formed, and the display medium material (three-color cholesteric liquid crystal of Yongri Chemical Co., Ltd.) is filled in the retaining wall. In the case of (in the groove), the flattening of the dielectric material between the retaining walls (in the groove) was observed by an optical microscope, and the observation results are shown in Table 2 below.

Comparative Example 1 shown in Table 2 is a single-layer structure retaining wall using a photosensitive material (manufacturing example 1) which is the most repellent liquid crystal, and the cholesteric liquid crystal is repelled to the middle by the two side walls, and Comparative Example 9 is the most cholesteric liquid crystal. (Manufacturing Example 14) The single-layer structure of the retaining wall, so the printed cholesteric liquid crystal will adsorb to both sides of the retaining wall and the surface will be concave. Therefore, in the optical microscope image, there is a white area in the middle of the liquid crystal. It is the lighter part of the liquid crystal. The dry film of Comparative Example 4 (Production Example 9) was preferable to the flattening effect of the cholesteric liquid crystal as compared with the other single-layer retaining walls, but the flattening effect required for the display was not obtained.

The first embodiment, the second embodiment and the comparative example 10 shown in Table 2 are double-walled retaining wall structures, and the lower layer of the retaining wall of the first embodiment and the second embodiment uses the manufacturing example 9 which is preferable for the flattening effect of the cholesteric liquid crystal. In the case of using the photosensitive material for repelling cholesteric liquid crystal in the wall layer, the production method of Example 7 and Production Example 1 was good, and the flattening effect of the cholesteric liquid crystal was good. In Comparative Example 10, the photosensitive material using the most cholesteric liquid crystal in the lower layer of the barrier wall (Production Example 14) was used. In the upper layer, a photosensitive material that repels cholesterol liquid crystal (Production Example 5) was used, and the flattening effect on the cholesteric liquid crystal was inferior to those of Examples 1 and 2.

As shown in FIG. 3E, a plurality of upper covers 32 are formed over the display medium material. The upper cover may be a polymer protective layer. In addition, a bonding process of the substrate 36 and the lower substrate 16 on the second conductive layer 34 is performed, such as a hot roller pressing process. The upper substrate is a glass substrate or a plastic substrate, and the second conductive layer 34 is made of an inorganic conductive material or an organic conductive material, and may include an active or passive driving circuit.

Since the photosensitive dry film of the present invention has two or more layers and the upper and lower layers have different surface properties, and the different surface properties are derived from the results after photopolymerization, the surface properties are permanent, unlike electricity. The surface properties of the pulp treatment will quickly fade away over time.

Since the present invention first applies a photosensitive dry film having an upper layer and a lower layer on the surface of the substrate, and then performs a patterning process to define a plurality of retaining walls in the photosensitive dry film, and then fills the display medium material between the retaining walls. (in the groove); the retaining wall constructed by the double-layer photosensitive dry film with different characteristics described above can effectively improve the material flattening problem caused by the single-layer structure retaining wall when the display is conventionally manufactured, and is constructed by two processes. The problem of complicated manufacturing process of the double-layer structure retaining wall, the use of the toxic gas generated by the plasma surface treatment and the problem of only temporary surface modification characteristics.

2‧‧‧lower substrate

3‧‧‧Substrate

4‧‧‧Upper substrate

6‧‧‧Liquid crystal materials

7‧‧‧Retaining wall

8‧‧‧Retaining wall

9‧‧‧Display media material

10‧‧‧Upper cover

12‧‧‧First conductive film

14‧‧‧Second conductive film

16‧‧‧lower substrate

18‧‧‧ Conductive layer

20‧‧‧ dry film

20a‧‧‧Upper photoresist layer

20b‧‧‧ lower photoresist layer

22‧‧‧Photomask

24‧‧ ‧ retaining wall

24a‧‧ ‧ wall layer

24b‧‧‧Under the wall

26‧‧‧ Groove

28‧‧‧Inkjet head

30‧‧‧Display media material

32‧‧‧Upper cover

34‧‧‧Second conductive layer

36‧‧‧Upper substrate

1 is a schematic cross-sectional view showing a display substrate of a single-layer liquid crystal structure in a prior art.

Fig. 2 shows a case where the flatness of the dielectric material is not good after being filled in the substrate.

3A to 3E show a preferred embodiment of a method of manufacturing the display of the present invention.

16. . . Lower substrate

18. . . Conductive layer

twenty four. . . Retaining wall

24a. . . Wall layer

24b. . . Lower wall

30. . . Display media material

32. . . Upper cover

34. . . Second conductive layer

36. . . Upper substrate

Claims (17)

A method for manufacturing a display, comprising the steps of: providing a lower substrate having a first conductive layer; forming a plurality of retaining walls on the lower substrate; filling a display medium material between the retaining walls; forming an upper cover on the display medium material And performing a bonding process of the second conductive layer and the lower substrate, wherein the retaining walls are formed by: forming a dry film on the lower substrate; placing a photomask over the dry film; and utilizing once a lithography process of patterning the dry film to form a plurality of barrier walls, wherein the dry film has at least two or more photoresist layers, the photoresist layers comprising a photosensitive resin and a surface modifier, and at least two The photoresist layer contains different surface modifiers. The method of claim 1, wherein the dry film has an upper photoresist layer and a lower photoresist layer. The method of claim 2, wherein a contact angle of the upper photoresist layer with the display medium material is greater than a contact angle of the lower photoresist layer with the display medium material. The method of claim 2, wherein the thickness of the lower photoresist layer is equivalent to a thickness of the display medium material filled between the barrier walls. The method of claim 1, wherein the surface modifying agent is selected from the group consisting of paraffin wax, decane, Novalac phenolic resin, fluorine sulfonate, and silicone. The method of claim 1, wherein after the dry film is patterned, the dry film is further cured. The method of claim 6 wherein the curing comprises a UV curing. The method of claim 6, wherein after curing the dry film, a baking process is further included. The method of claim 8, wherein the baking process has a temperature of from about 100 ° C to about 150 ° C. The method of claim 8, wherein the baking process is for a period of from about 30 to about 90 minutes. The method of claim 1, wherein the thickness of the retaining wall is between 5 microns and 50 microns. The method of claim 1, wherein the width of the retaining wall is between 15 microns and 60 microns. The method of claim 1, wherein the distance between the barrier walls is from about 50 microns to about 250 microns. The method of claim 1, wherein the display medium material comprises cholesteric liquid crystals. The method of claim 1, wherein the method of forming a dry film on the lower substrate is laminating roller or vacuum lamination. The method of claim 1, wherein the method of filling the display medium material between the retaining walls is inkjet printing or vacuum injection. A display formed by the method of manufacturing the display of claim 1.