KR101018189B1 - Mathod for fabricating e-paper using Roll-to-Roll - Google Patents

Abstract

In the present invention, an electronic paper manufacturing method using a roll-to-roll process is proposed. Electronic paper manufacturing method using a roll-to-roll imprint process according to the present invention, by forming a partition structure using a roll-to-roll imprint process it is possible to uniformly arrange the twisted ball to improve the screen contrast ratio have. In addition, by manufacturing the electronic paper in a roll-to-roll process, the manufacturing process is simplified, there is an effect that can reduce the manufacturing cost and mass production.

Twisted ball, electronic paper, bulkhead, roll-to-roll

Description

Electronic paper manufacturing method using roll-to-roll process {Mathod for fabricating e-paper using Roll-to-Roll}

The present invention relates to a method for producing electronic paper using a roll-to-roll process, and more particularly, to provide an electronic paper manufacturing method using a roll-to-roll process in which a contrast ratio is improved and mass production is possible.

Electronic paper is literally thin and flexible like paper, but it is a device that can be displayed using electronic signals rather than printed with ink. E-paper that looks like a book rest can be bent or rolled around to read electronic documents anywhere. It is an advanced technology that is a step further from the conventional paper-based printing.

It is expected that these electronic papers will replace ordinary paper in the near future. Electronic paper basically has the same operating principle as LCD. The difference is that the LCD looks bright with light coming from behind and the paper looks a bit dark because it looks through the reflection. Looking at the advantages of electronic paper, the LCD screen disappears immediately when the power is turned off, but the electronic paper can maintain the screen even when the power is unplugged. In other words, even when the power is turned off, the screen is preserved and power is consumed only when the screen is changed. In addition, LCDs are hard to see under bright sunlight, but electronic paper is a reflection type that uses external light to read information easily even under bright light. In addition, LCDs can cause eye fatigue when used for more than an hour, while electronic paper has the advantage of no eye fatigue because the paper is food-like.

These advantages make electronic papers suitable for a wide range of applications, including e-books with paper-like sides and moving illustrations, self-renewable newspapers, reusable paper displays for mobile phones, disposable TV screens and electronic wallpaper. It has a huge potential market.

The technical approach for implementing such electronic paper is largely a method using a liquid crystal, a method using an organic EL, an electrophoretic method, a method using two-color rotating particles (for example, twist ball), an electrochromic method Etc. Among them, the twisted ball is divided into two parallel translucent sheets (hereinafter, the elastomer matrix), in which the twisted balls of the hemispheres are divided into white and black forms made of the same material as the elastomer. It is common to have a configuration arranged in a large number.

Twist ball has optical and electrical anisotropy. That is, a negative charge is charged to the white hemisphere part, and a static charge is charged to the black hemisphere part, thereby forming a permanent dipole. The twist balls are also coated with liquid to enable rotation in the elastomer matrix. That is, the electronic paper using the twist ball can display a desired image by applying an electric field to the elastomer matrix and selectively rotating the twist ball.

For electronic paper using such twist balls, it is important to arrange the twist balls uniformly in the elastomer matrix for the clarity of the screen. However, the electronic paper using the twisted ball has a poor contrast ratio due to the non-uniformity of the twisted ball generated in the process of attaching the twisted ball to the elastomer matrix. In addition, there is a problem in that the process is complicated because the liquid must be coated on each of the twist balls for rotation.

The present invention is to solve the above-mentioned problems, an object of the present invention is to form a partition structure through a roll-to-roll imprint process to uniformly arrange the twist ball to improve the screen contrast ratio, the process of injecting the twist ball and fluid liquid It is to provide an electronic paper manufacturing method that can be simplified. In addition, it is possible to further simplify the manufacturing process by using a roll-to-roll process to reduce the manufacturing cost, and to provide an electronic paper manufacturing method capable of mass production.

Electronic paper manufacturing method using a roll-to-roll process according to an aspect of the present invention for achieving the above object, the step of forming a plurality of partitions in a roll-to-roll imprint process on the first substrate; Injecting twist balls into a plurality of cells defined by the plurality of partitions; Injecting a liquid dielectric into the cell into which the twist ball is injected; And bonding the second substrate made of a transparent material to the first substrate in a roll-to-roll process so as to face the first substrate.

In this case, the electronic paper manufacturing method using the roll-to-roll process, the step of forming a first substrate by laminating a resin layer on a conductive substrate before the partition wall forming step; And forming an electrode on the second substrate.

The electronic paper manufacturing method using the roll-to-roll process may further include forming electrodes on the bonded first substrate and the second substrate, respectively.

In addition, the forming of the partition wall may be performed by pressing the first substrate with a roll stamp having embossed and intaglio patterns corresponding to the plurality of partition walls, and the forming of the partition wall may include the height of the partition wall being It is formed to be larger than the particle diameter of the twist ball, characterized in that the width of the cell is formed to be larger than the particle diameter of the twist ball.

In addition, the twist ball injection step, characterized in that the injection of the twist ball into each cell by using a squeeze, the liquid dielectric injection step, the liquid phase between the plurality of partition walls and the twist ball using a squeeze It is characterized by pushing the dielectric of.

In addition, the step of bonding the first substrate and the second substrate, characterized in that by performing the pressing while moving the first substrate and the second substrate between the upper and lower rollers, the twist ball is It has at least two surfaces that differ in optical and charging characteristics, and is rotatable by electrical action.

The electronic paper manufacturing method according to the present invention can arrange the twist ball evenly on the partition structure formed through the roll-to-roll imprint process, and thus the screen contrast ratio is improved, and the process of coating the liquid on each twist ball is performed inside the cell. As a result of the liquid injection process, the manufacturing process is simplified. In addition, the electronic paper manufacturing method according to the present invention can simplify the bulkhead forming process, twist ball and liquid injection process, and the pressing process of the upper and lower substrates in a batch process by using a roll-to-roll process to reduce the manufacturing cost and mass There is an effect that can be produced.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. In addition, it should be considered that elements of the drawings attached to the present specification may be enlarged or reduced for convenience of description.

1 is a cross-sectional view showing the electronic paper produced by the electronic paper manufacturing method using a roll-to-roll process according to an embodiment of the present invention. Referring to FIG. 1, the electronic paper 100 according to the present embodiment includes a lower substrate 110, a twist ball 120, and an upper substrate having a plurality of cells A defined by a plurality of partitions 111. 140). Here, the twist ball 120 is disposed inside the cell A. In addition, the electronic paper 100 is filled with a liquid dielectric 130 inside each cell A, that is, between the twist ball 120 and the plurality of partitions 111. The upper substrate 140 is disposed and attached to a position opposite to the lower substrate 110.

Specifically, the lower substrate 110 and the upper substrate 140 is preferably made of a flexible material of the glass or flexible plastic type, in order to use the roll-to-roll process in the present invention the flexible material is more desirable. In this case, the lower substrate 110 should adjust the thickness of the lower substrate forming the bottom surface of the cell so that the magnetic field can be applied to the twist ball of each cell, and the electrode (not shown) patterned corresponding to each cell It is further provided. Similarly, the upper substrate 140 also has to adjust its thickness so that a magnetic field may be applied to the twist ball of each cell, and further includes a transparent electrode (not shown) such as ITO on the front of the upper substrate 140.

Alternatively, the lower substrate 110 may be an insulating resin layer formed on the conductive substrate. At this time, a partition structure is formed in an insulating resin layer. At this time, the conductive substrate is used as an electrode. In addition, the upper substrate 140 may be formed of a light transmissive material, and may be formed of a transparent material, for example, ITO.

In the present invention, the lower substrate 110 and the upper substrate 140 will be described as being made of a flexible material in order to use a roll-to-roll process. As such, a voltage is applied to the twist ball 120 by external electrodes (not shown) formed on the lower substrate 110 and the upper substrate 140, and the twist ball 120 rotates by the applied voltage. An image is displayed.

The partition wall 120 is formed integrally with the lower substrate 110 through a roll-to-roll imprint process, and divides a space between the lower substrate 110 and the upper substrate 140 to provide a plurality of cells. In the present invention, the space defined by the partition wall 120 is defined as the cell A. And, the height of the partition wall 120 is larger than the particle diameter of the twist ball 130, thereby preventing the departure of the twist ball injected into the cell. The material of the partition wall is not particularly limited as long as it is a flexible material, and may be a thermosetting resin or a UV curable resin. One twist ball 120 is disposed in the cell A defined by the partition wall 120, and a liquid dielectric 130 is filled between the partition wall 111 and the twist ball 120. The width of the cell A is larger than the particle diameter of the twist ball 120, so that the twist ball injected into the cell is rotatable.

That is, the electronic paper according to the present invention may uniformly arrange the twist ball in the cell defined by the partition wall formed by the roll-to-roll imprint process. Accordingly, the spacing and shape of the twist balls injected into the cell space can be uniform for each cell, thereby improving the contrast ratio of the screen.

Hereinafter, the manufacturing process of the electronic paper using the roll-to-roll process according to an embodiment of the present invention. 2A to 2D are cross-sectional views illustrating a manufacturing process of electronic paper using a roll-to-roll process according to an embodiment of the present invention. Here, in order to use the roll-to-roll process, the lower substrate 110 and the upper substrate 140 will be limited to being made of a flexible material.

Electronic paper manufacturing process using a roll-to-roll process according to an embodiment of the present invention comprises the steps of forming a plurality of partitions in a roll-to-roll imprint process on the first substrate; Injecting twist balls into a plurality of cells defined by the plurality of partitions; Injecting a liquid dielectric into the cell into which the twist ball is injected; And bonding the second substrate made of a transparent material to the first substrate in a roll-to-roll process so as to face the first substrate.

First, a method of forming the partition 111 on the lower substrate 110 by a roll-to-roll imprint process will be described. 2A is a cross-sectional view illustrating a process of forming a partition on a lower substrate in the electronic paper manufacturing method using the roll-to-roll process according to an embodiment of the present invention.

As shown in FIG. 2A, the partition wall 111 is formed by applying pressure to the lower substrate 110 with a roll stamp B having an embossed and engraved pattern corresponding to a cell shape to be formed. In this case, a pattern corresponding to the embossed and intaglio patterns of the roll stamp B is formed on the lower substrate 110. That is, the lower substrate 110 corresponding to the embossed pattern of the roll stamp B is compressed, and the lower substrate 110 corresponding to the intaglio pattern of the roll stamp B forms a plurality of partitions 111. As a result, the cell A defined by the partition wall 111 is formed. The width of the cell space A may be slightly larger than the particle size of the twist ball, and the height of the partition wall is larger than the particle size of the twist ball 120.

In this case, the roll stamp B may be subjected to self-assembled monolayer (SAM) coating. When the SAM coating is applied to the roll stamp B, when the roll stamp B is pressed onto the lower substrate 110, the roll stamp B and the lower substrate 110 which are pressed together may be easily separated. The lower substrate 110 is not particularly limited as long as it is a flexible material as described above, and may be a thermosetting resin or a UV curable resin.

On the other hand, in the case of using the thermosetting epoxy material as the lower substrate 110, in order to be able to form the partition 111 more efficiently, the imprint process may be dualized. That is, the roll stamp B and the lower substrate 110 are thermally compressed for 30 minutes within a temperature range where the viscosity of the lower substrate 110 is lowest (for example, about 100 ° C.), and the pressing state is maintained. After curing the lower substrate 110 by raising the temperature to a temperature range (for example, about 180 ℃) that the lower substrate 110 can be cured, the method of separating the roll stamp (B) and the lower substrate 110 Can be used. Using this method, the pattern formed on the roll stamp B can be more efficiently transferred to the lower substrate 110, and the shape of the pattern transferred to the lower substrate 110 during or after separation, that is, the partition wall This can be maintained efficiently. As described above, since the partition wall is manufactured by an imprint process using the roll stamp B, various cell shapes and sizes can be adjusted. That is, the shape and size of the cell also vary as the pattern of the roll stamp B is manufactured in various ways.

Next, a method of arranging the twist balls 120 in the cell space formed on the lower substrate 110 will be described. 2B is a cross-sectional view illustrating a process of injecting a twist ball into a cell in an electronic paper manufacturing method using a roll-to-roll process according to an embodiment of the present invention.

As shown in FIG. 2B, the twist balls 120 are injected onto the lower substrate 110 having the partition walls through the nozzles, and the twist balls 120 injected using the squeeze C are injected into the cell. The filling rate of the twist ball 120 in the cell can be increased by continuously repeating the coating process using the squeeze (C). At this time, in order to further increase the filling rate of the twist ball in the cell, a plurality of randomly stacked twist balls are injected into the cell space of the lower substrate by applying swaying motion to the lower substrate 110. In addition, since the height of the partition wall 111 is larger than the particle diameter of the twist ball 120, the injected twist ball may be prevented from being separated.

Next, a method of injecting the liquid dielectric body 130 into the lower substrate 110 into which the twist ball is injected into the cell space will be described. 2C is a cross-sectional view illustrating a process of injecting a liquid dielectric into a cell into which a twist ball is injected in the electronic paper manufacturing method using the roll-to-roll process according to an embodiment of the present invention.

As shown in FIG. 2C, the liquid dielectric 130 is applied onto the lower substrate 110 into which the twist ball 120 is injected through the nozzle. The applied liquid dielectric 130 is pushed to be filled in the cell, that is, between the partition 111 and the twist ball 120 using the squeeze D.

Next, a method of attaching the upper substrate 140 on the lower substrate 110 will be described. 2D is a cross-sectional view illustrating a process of attaching an upper substrate to a lower substrate into which a twist ball and a liquid dielectric are injected in a roll-to-roll process in the electronic paper manufacturing method using the roll-to-roll process according to an embodiment of the present invention. .

As shown in FIG. 2D, the upper substrate 140 is stacked to face the lower substrate 110, and then the upper surface of the partition 111 and the upper substrate 140 of the lower substrate 110 are attached by a roll-to-roll process. do. Specifically, the upper and lower rollers E and E 'are rotated, and the upper and lower rollers are compressed by moving the lower substrate 110 and the upper substrate 140 between the upper and lower rollers E and E'. Perform the attachment of the substrate. That is, the upper surface of the barrier rib 111 and the upper substrate 140 of the lower substrate 110 are attached by pressing the upper and lower rollers E and E '. Here, the adhesive layer is formed on one surface of the upper substrate 140 attached to the upper surface of the partition wall 111. The adhesive layer is a UV-curable material, a thin adhesive layer coated on the upper substrate 140 to a thickness of about 10㎛, preferably within 5㎛. As described above, after the thin adhesive layer (not shown) is formed on the upper substrate 140, the thin adhesive layer of the upper substrate 140 is disposed to adhere to the upper surface of the partition wall, and the upper and lower rollers E and E 'are disposed. Squeeze through. Then, when UV is exposed, the upper substrate 140 is attached only to the upper surface of the partition wall 111 of the lower substrate 110.

Next, although not shown, after the upper substrate 140 is attached to the lower substrate 110, an external electrode (not shown) is further formed below the lower substrate 110 and on the upper substrate 140. In this case, the lower substrate 110 may be formed with an electrode patterned to correspond to each cell, and the upper substrate 140 may be formed with a transparent electrode such as ITO on the entire surface to form an external electrode. By such an external electrode, a twisted ball can be rotated by applying an electric field to a desired cell to display a desired image.

Therefore, the process shown in FIGS. 2A to 2D is continuously performed in a roll-to-roll process. Through this process, the electronic paper as shown in FIG. 1 is manufactured. In other words, the electronic paper manufacturing method using the roll-to-roll process according to the present invention can form a partition structure on the lower substrate to uniformly arrange the twist ball, it is possible to prevent the phenomenon that the twist ball is laminated in a multi-layer, screen The contrast ratio of can be improved. In addition, the process of coating a liquid on each twist ball is unnecessary, and the manufacturing process can be simplified by injecting a liquid dielectric into the cell defined by the partition structure.

In addition, in the electronic paper manufacturing method using the roll-to-roll process according to the present invention, since the cells are manufactured using the imprint process, the space between the cells can be partitioned in advance, and the process of forming the partition structure by using the roll-to-roll process, twisting Since the process of injecting the ball, the process of injecting the liquid dielectric, and the process of attaching the upper and lower substrates can be performed in a batch, the manufacturing cost can be reduced and mass production can be performed. That is, the electronic paper manufacturing method using the roll-to-roll process according to the present invention, when using the upper and lower substrate as a flexible plastic substrate, mass production by a continuous roll-to-roll process similar to the paper printing method This makes it possible to manufacture at low cost.

3 illustrates a top plan view of a lower substrate on which a partition wall is formed according to the process illustrated in FIG. 2A. As shown in FIG. 3, in the present embodiment, a cell having a rectangular shape is formed. Here, the shape of the cell can be changed by manufacturing the shape of the roll stamp in various ways.

4 illustrates a top plan view of a lower substrate on which twist balls are disposed according to the process shown in FIG. 2B. As shown in FIG. 4, the twist balls 120 are disposed one by one inside the cell formed on the lower substrate 110.

The present invention is not limited to the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims, and various forms of substitution, modification, and within the scope not departing from the technical spirit of the present invention described in the claims. It will be apparent to those skilled in the art that changes are possible.

1 is a cross-sectional view showing the electronic paper produced by the electronic paper manufacturing method using a roll-to-roll process according to an embodiment of the present invention.

2A is a cross-sectional view illustrating a process of forming a partition on a lower substrate in the electronic paper manufacturing method using the roll-to-roll process according to an embodiment of the present invention.

2B is a cross-sectional view illustrating a process of injecting a twist ball into a cell in an electronic paper manufacturing method using a roll-to-roll process according to an embodiment of the present invention.

2C is a cross-sectional view illustrating a process of injecting a liquid dielectric into a cell into which a twist ball is injected in the electronic paper manufacturing method using the roll-to-roll process according to an embodiment of the present invention.

2D is a cross-sectional view illustrating a process of attaching an upper substrate to a lower substrate into which a twist ball and a liquid dielectric are injected in a roll-to-roll process in the electronic paper manufacturing method using the roll-to-roll process according to an embodiment of the present invention. .

3 illustrates a top plan view of a lower substrate on which a partition wall is formed according to the process illustrated in FIG. 2A.

4 illustrates a top plan view of a lower substrate on which twist balls are disposed according to the process shown in FIG. 2B.

Claims (11)

Preparing a roll stamp on which a self-assembled monolayer (SAM) coating has been performed; Thermally compressing the roll stamp and the first substrate within a temperature range in which the viscosity of the first substrate is lowest; Hardening the first substrate by raising the temperature to a curing temperature of the first substrate while maintaining a crimped state; Separating the roll stamp from the first substrate to form a partition wall forming a plurality of cells, the height of the partition wall is larger than the particle diameter of the twist ball to be injected, the width of the plurality of cells defined by the plurality of partition walls Forming a larger than the particle diameter of the twist ball; Injecting a twist ball into the plurality of cells by shaking the first substrate from side to side; Injecting a liquid dielectric into the cell into which the twist ball is injected; And Adhering a second substrate made of a transparent material to the first substrate in a roll-to-roll process so as to face the first substrate. The method of claim 1, Forming a first substrate by laminating a resin layer on a conductive substrate before the partition forming step, the electronic paper manufacturing method using a roll-to-roll process, characterized in that it further comprises. The method of claim 2, Forming an electrode on the second substrate; Electronic paper manufacturing method using a roll-to-roll process characterized in that it further comprises. The method of claim 1, Forming an electrode on each of the bonded first substrate and the second substrate; Electronic paper manufacturing method using a roll-to-roll process characterized in that it further comprises. The method of claim 1, The forming of the partition wall, the electronic paper manufacturing method using a roll-to-roll process, characterized in that the first substrate is pressed by a roll stamp formed with embossed and intaglio patterns corresponding to the plurality of partitions. delete delete The method of claim 1, The twist ball injection step, the electronic paper manufacturing method using a roll-to-roll process, characterized in that for injecting the twist ball into each cell by using a squeeze. The method of claim 1, The liquid phase dielectric injection step, the electronic paper manufacturing method using a roll-to-roll process, characterized in that for pushing the liquid dielectric between the plurality of partition walls and the twist ball using a squeeze. The method of claim 1, The bonding of the first substrate and the second substrate may be performed by pressing the first substrate and the second substrate by pressing the first substrate and the second substrate while moving the first substrate and the second substrate therebetween. Manufacturing method. The method of claim 1, The twist ball has at least two surfaces having different optical and charging characteristics and is rotatable by electrical action.

Images