KR101115986B1 - Electronic paper display device using collision electrification and driving method thereof - Google Patents

Abstract

The present invention discloses a collision charging type electronic paper display device and a driving method thereof. According to an aspect of the present invention, there is provided a collision charging type electronic paper display device comprising: an upper substrate; A lower substrate facing the upper substrate; A plurality of upper electrodes formed at predetermined intervals below the upper substrate; A lower electrode formed on the lower substrate; A voltage driver configured to apply voltages having opposite polarities between adjacent electrodes in the plurality of upper electrodes; Interposed between the upper electrode and the lower electrode, and comprises a plurality of cells containing a plurality of particles.

According to the present invention, it is possible to improve the charging characteristics of the particles to lower the operating voltage and to provide more clear picture quality.

Collision charging, electronic paper, upper electrode, charging characteristics

Description

Collision charging electronic paper display device and driving method thereof {ELECTRONIC PAPER DISPLAY DEVICE USING COLLISION ELECTRIFICATION AND DRIVING METHOD THEREOF}

The present invention relates to an electronic paper display device and a driving method thereof, and more particularly, to an apparatus and a method for improving charging characteristics of particles included in a collision charging type electronic paper display device.

In recent years, due to the necessity of transforming into an information communication and sharing method corresponding to the information society, technology development of electronic paper having excellent flexibility, portability, light weight, etc. has been accelerated, It is entering. Electronic paper is cheaper than conventional flat panel display panels and does not require backlighting or continuous recharging like liquid crystal displays, so it can be driven with very little energy, leading to energy efficiency. In addition, electronic paper is very sharp like conventional papers and inks, has a wide viewing angle, and has its own memory effect, so that an image can be displayed for a long time without large power consumption.

These advantages allow electronic paper to display moving illustrations while retaining some of the traditional features of paper, making it a huge choice for electronic books, self-renewing newspapers, reusable paper displays for mobile phones, disposable TV screens and electronic wallpaper. Applicable to the field and has a huge potential market.

There are many technical approaches to electronic paper implementation, including liquid crystal method, organic EL, reflective film reflective display, electrophoresis, twist ball, electrochromic method, and mechanical reflective display method. The most notable method is the electrophoretic phenomenon.

  Particularly, among the electrophoretic methods, the dry collision type electrified electronic paper display device has a high viscosity in the pixel space, and thus the response speed is considerably fast, which is suitable for realizing a video. In addition, since the image remains for a long time due to the electrostatic characteristic even after the electric field is removed, there is an advantage that the memory characteristics are superior to other electronic paper display device implementation method.

1 is a cross-sectional view schematically showing the configuration of some cells of a conventional collision charging type electronic paper display device.

As shown in the drawing, a general collision charging type electronic paper display device is formed on the inner surfaces of the upper and lower substrates 111 and 112 and the upper and lower substrates 111 and 112, respectively, which are disposed to face each other and are made of a transparent material. An insulating film 130 formed on the upper and lower electrodes 121 and 122, inner surfaces of the upper and lower electrodes 121 and 122, and a partition wall 170 that isolates each cell and supports the upper and lower substrates 111 and 112. And particles 150 and 160 charged with different charges.

2 is a cross-sectional view illustrating an arrangement state of particles when a display voltage is applied to a conventional electronic paper display device.

As shown in FIG. 2, when a positive voltage is applied to the upper electrode 221 and a negative voltage is applied to the lower electrode 222, the negatively charged particles 260 move toward the upper electrode 221 and the lower electrode 222. The positively charged particles 250 move to the side. Therefore, when viewed from the upper electrode 221 side, the color of the negatively charged particles 260 is displayed. On the other hand, when the polarities of the voltages applied to the upper electrode 221 and the lower electrode 222 are reversed, the negatively charged particles 260 move toward the lower electrode 222 and the positively charged particles 250 move toward the upper electrode 221. Therefore, when viewed from the upper electrode 221 side, the color of the positively charged particles 250 is displayed.

However, for various reasons, such as when the electronic paper display device has not been used for a long time or when a certain screen is continuously displayed for a long time, the particles of the electronic paper display device may not be sufficiently charged or may be stuck to the insulating film side. In addition, the particles may stick together. In this case, even when the display voltage is applied, the particles may not move properly, and thus display of clear image quality is difficult. In order to solve such a problem, the conventional collision charging type electronic paper display device applies a collision voltage to the upper electrode and the lower electrode so that the particles collide with each other before applying the display voltage, thereby enhancing the charging characteristics of the particles. It is adopted.

However, the conventional method alone has a limitation in uniformly enhancing the charging characteristics of the particles. Particles vary in their charging capacity as the use time elapses, but even if the particle agglomeration is eliminated through particle collision does not eliminate the variation in the charging capacity of the particles. Therefore, even in the case of the conventional collision charging type electronic paper display device, there is still a problem that the sharpness of the image quality is lowered due to the nonuniformity of the particle charging characteristics. In order to compensate for this problem, a method of increasing the operating voltage may be used, but increasing the operating voltage may cause the particles to be destroyed by rapidly increasing the number of collisions between the particles due to the excessively high speed of movement of the sufficiently charged particles. Another problem arises.

Accordingly, the present invention has been made to solve the problems of the prior art as described above, and the collision charging type electronic paper display device and its driving that can improve the charging characteristics of the particles to lower the operating voltage and provide more clear image quality It is an object to provide a method.

In order to achieve the above object, the collision charging type electronic paper display device according to the present invention, the upper substrate; A lower substrate facing the upper substrate; A plurality of upper electrodes formed at predetermined intervals below the upper substrate; A lower electrode formed on the lower substrate; A voltage driver configured to apply voltages having opposite polarities between adjacent electrodes in the plurality of upper electrodes; It is characterized by including a plurality of cells interposed between the upper electrode and the lower electrode, the plurality of cells including a plurality of particles.

In addition, the collision charging type electronic paper display device according to the present invention, the upper substrate; A lower substrate facing the upper substrate; An upper electrode formed under the upper substrate; A plurality of lower electrodes formed at predetermined intervals on the lower substrate; A voltage driver configured to apply voltages having opposite polarities between adjacent electrodes in the plurality of lower electrodes; And a plurality of cells interposed between the upper electrode and the lower electrode and including a plurality of particles.

In addition, a plurality of cells including a plurality of particles according to the present invention for achieving the above object, a plurality of upper electrodes formed at predetermined intervals, a lower electrode facing the upper electrode, and a plurality of upper electrodes The method for driving an electronic paper display device having a voltage driver to be applied may include applying a voltage having opposite polarities between adjacent electrodes to the plurality of upper electrodes.

The electronic paper display further includes a plurality of cells including a plurality of particles, a plurality of lower electrodes formed at predetermined intervals, an upper electrode facing the lower electrode, and a voltage driver for applying a voltage to the lower electrodes. The method for driving the device is characterized in that the voltage driver comprises applying a voltage of opposite polarity between adjacent electrodes to the plurality of lower electrodes.

According to the present invention, the particles of the collision charging type electronic paper display device are sufficiently charged even at a low voltage, and the charging state between the particles can be made uniform. Therefore, not only the voltage for charging the particles can be lowered, but also the display voltage for moving the particles for display can be reduced, thereby reducing the display device driving cost. In addition, it is possible to obtain a clear image quality by uniform movement of the particles when the operating voltage is applied by equalizing the state of charging between the particles, and to prevent some particles from moving at an excessively high speed to prevent the destruction of the particles due to collision between the particles. Can be.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

3 is a cross-sectional view illustrating some cells in an electronic paper display device according to a preferred embodiment of the present invention.

An electronic paper display device according to an exemplary embodiment of the present invention includes an upper substrate, a lower substrate, an upper electrode 321, a lower electrode 322, a voltage driver 380, and a plurality of particles 350 and 360. It includes a plurality of cells. In addition, although not essential, an insulating film 330 may be included between the upper electrode 321 and the plurality of cells, between the lower electrode 322, and the plurality of cells, and a partition wall may be disposed between the upper electrode 321 and the lower electrode 322. 370 may be provided.

Referring to FIG. 3, the upper electrode 321 formed under the upper substrate (not shown) includes a plurality of electrodes, and the plurality of electrodes are formed at predetermined intervals. In general, the distance between the upper electrode 321 and the lower electrode 322 should be larger than the diameter of the particles 350 and 360 to accommodate the particles 350 and 360 in the cell, so that the size of several micrometers to several tens of micrometers. Has However, the distance between the plurality of upper electrodes 321 can be reduced to a range that can be manufactured in the process regardless of the size of the particles 350 and 360, and can be designed to several micrometers or less at present.

Preferably, the predetermined interval between the plurality of upper electrodes 321 is shorter than the interval between the upper electrode 321 and the lower electrode 322. As shown in FIG. 3, when voltages of opposite polarities are applied between the adjacent upper electrodes 321 by the voltage driver 380 described later, adjacent upper electrodes 321 are charged with opposite polarities to each other and are generated. The particles 350 and 360 move by the electrostatic force and are attached to the lower portion of the upper electrode 321. In this process, the particles 350 and 360 collide with each other to remove agglomeration of particles, and charges are transferred from the upper electrode 321 to the surfaces of the particles 350 and 360, thereby improving charging characteristics of the particles. Electrostatic force, also called coulomb force, has a constant relationship with the amount of charge and distance according to Coulomb's law. That is, since the electrostatic force is inversely proportional to the square of the distance corresponding to the distance between the adjacent upper electrodes 321, the smaller the interval between the upper electrodes 321 may cause a larger electrostatic power even at a lower voltage. When the greater electrostatic force is induced, the driving force of the particles 350 and 360 increases, so that the particles move easily, thereby applying a voltage opposite to the upper electrode 321 and the lower electrode 322 to improve the charging characteristics of the particles. The voltage level can be lowered than in the conventional case. As described above, the predetermined interval between the plurality of upper electrodes 321 may be designed to be equal to or less than the interval between the upper electrode 321 and the lower electrode 322. Therefore, the present invention can increase the charging characteristics of the particles even at a lower applied voltage than the conventional collision charging electronic paper display device.

The lower electrode 322 is formed on the lower substrate (not shown), and a display voltage for displaying an image, a character, or the like is applied. On the other hand, the lower electrode 322 can also be composed of a plurality of electrodes formed at a predetermined interval, like the upper electrode 321, in this case, as described later by applying a collision voltage to the plurality of lower electrodes to improve the charging characteristics of the particles Can be used to enhance.

The voltage driver 380 applies a voltage to the plurality of upper electrodes 321, but allows voltages of opposite polarities to be applied between adjacent upper electrodes 321. When voltage is applied by the voltage driver 380 as shown in FIG. 3, the negatively charged particles 360 in the center cell of the figure move to the upper electrode 321, while negatively charged particles ( 360 moves toward the lower electrode 322 due to the electrostatic repulsive force with the particles moved upward.

4 is a cross-sectional view illustrating some cells in an electronic paper display device according to another exemplary embodiment of the present invention.

Referring to FIG. 4, the plurality of upper electrodes 421 are formed at predetermined intervals above the cell centers instead of the partition walls 470. Therefore, when voltage is applied by the voltage driver 480 as shown in the figure, the negatively charged particles 460 on the left side move toward the upper electrode 421 based on the center of the figure, and the negatively charged particles 460 on the right side. They move toward the lower electrode 422 due to the electrostatic repulsion of the particles on top. In addition, the interval between the upper electrode 421 may be located at any point regardless of the position of the partition wall 470, the present invention can be preferably applied to a structure without the partition wall 470.

The partition wall 470 not only separates the plurality of cells into unit cells but also supports the upper and lower substrates, and prevents the charged particles 450 and 460 included in the cells from flowing out of the cells. In addition, the insulating layer 430 prevents the charged particles 450 and 460 from sticking to the upper and lower electrodes 421 and 422.

Meanwhile, the substrate and the electrode of the electronic paper display device according to the present invention may be flexible. Unlike most displays currently in use, electronic paper can greatly improve portability and visibility due to its flexibility along with weight, because the use of flexible substrates and electrodes makes it easier to achieve this goal. On the other hand, the present invention is not limited to the physical structure of the electronic paper display device, it is a matter of course that the electronic paper having a structure other than the above-described structure can be applied substantially the same.

5 is a flowchart schematically illustrating a method of driving an electronic paper display device according to an embodiment of the present invention.

Referring to FIG. 5, in order to reinforce the charged state of the particles of the electronic paper display device, first, the voltage driver applies a voltage having opposite polarities between adjacent electrodes to the plurality of upper electrodes (S1). Preferably, after the step S1, a voltage in a direction opposite to the step S1 is applied to the upper electrode (S2). More preferably, the step S1 and step S2 are repeatedly performed alternately. As such, by repeatedly performing the steps S1 and S2, the particles can be sufficiently evenly charged. When the particles are sufficiently charged through the above process, a display voltage is applied to the upper electrode and the lower electrode to display a character or an image to be displayed through movement of the colored charged particles (S3).

6 and 7 are diagrams illustrating an application state of voltages to a plurality of upper electrodes according to an embodiment of the present invention.

6 and 7, the upper electrodes 621 and 721 and the lower electrodes 622 and 722 are formed of a plurality of electrodes and are arranged in parallel at regular intervals. In FIG. 6, a voltage having opposite polarity is applied between adjacent upper electrodes 621, and in FIG. 7, a voltage is applied to the upper electrode 721 in a direction opposite to that of FIG. 6. As described above with reference to FIG. 5, the voltage application state of FIGS. 6 and 7 is preferably repeated. In addition, unlike the above embodiment, with respect to an electrode group consisting of two or more adjacent electrodes, a voltage having the same polarity is applied to electrodes in the same group, and a voltage having opposite polarities is applied between adjacent groups, thereby charging characteristics of the particles. It is also possible to improve the form.

Meanwhile, in the above embodiments, voltages having opposite polarities are applied to adjacent upper electrodes with respect to the plurality of upper electrodes. On the contrary, voltages having opposite polarities are applied between adjacent lower electrodes with respect to the plurality of lower electrodes. It will be apparent to those skilled in the art that it is also possible to do so. It is also possible for voltages of opposite polarity to be applied between adjacent electrodes for both the upper and lower electrodes.

Although the invention has been described above by means of limited embodiments and drawings, the invention is not limited thereto and will be described below by the person skilled in the art and the technical spirit of the invention. Of course, various modifications and variations are possible within the scope of the claims.

1 is a cross-sectional view schematically showing the configuration of some cells of a conventional collision charging type electronic paper display device.

2 is a cross-sectional view illustrating an arrangement state of particles when a display voltage is applied to a conventional electronic paper display device.

3 is a cross-sectional view illustrating some cells in an electronic paper display device according to a preferred embodiment of the present invention.

4 is a cross-sectional view illustrating some cells in an electronic paper display device according to another exemplary embodiment of the present invention.

5 is a flowchart schematically illustrating a method of driving an electronic paper display device according to an embodiment of the present invention.

6 and 7 are diagrams illustrating an application state of voltages to a plurality of upper electrodes according to an embodiment of the present invention.

Claims (18)

In an electronic paper display device, An upper substrate; A lower substrate facing the upper substrate; A plurality of upper electrodes formed at predetermined intervals below the upper substrate; A lower electrode formed on the lower substrate; A voltage driver configured to apply voltages having opposite polarities between adjacent electrodes with respect to the plurality of upper electrodes before a display voltage is applied; And A plurality of cells interposed between the upper electrode and the lower electrode and including a plurality of particles Electronic paper display device comprising a. The method of claim 1, And the predetermined interval between the adjacent upper electrodes is shorter than the interval between the upper electrode and the lower electrode. The method of claim 1, Separating the cells at regular intervals, and further comprising a partition wall for supporting the upper substrate and the lower substrate. The method of claim 3, And the predetermined interval between the adjacent upper electrodes is located above the partition wall. The method of claim 3, And the predetermined interval between the adjacent upper electrodes is located at a portion other than an upper portion of the partition wall. In an electronic paper display device, An upper substrate; A lower substrate facing the upper substrate; An upper electrode formed under the upper substrate; A plurality of lower electrodes formed at predetermined intervals on the lower substrate; A voltage driver configured to apply voltages having opposite polarities between adjacent electrodes with respect to the plurality of lower electrodes before a display voltage is applied; And A plurality of cells interposed between the upper electrode and the lower electrode and including a plurality of particles Electronic paper display device comprising a. The method of claim 6, And the predetermined interval between the adjacent lower electrodes is shorter than the interval between the upper electrode and the lower electrode. The method of claim 6, Separating the cells at regular intervals, and further comprising a partition wall for supporting the upper substrate and the lower substrate. The method of claim 8, And the predetermined interval between the adjacent lower electrodes is located below the partition wall. The method of claim 8, The predetermined distance between the adjacent lower electrodes is located at a portion other than the lower portion of the partition wall. An electronic paper display device comprising a plurality of cells including a plurality of particles, a plurality of upper electrodes formed at predetermined intervals, a lower electrode facing the upper electrode, and a voltage driver for applying a voltage to the plurality of upper electrodes. In the driving method, (S1) before the display voltage is applied, the voltage driver applying a voltage having opposite polarities between adjacent electrodes to the plurality of upper electrodes; E-paper display device driving method comprising a. The method of claim 11, (S2) The method of driving the electronic paper display device, further comprising the step of applying a voltage having a polarity opposite to that of the step S1 to the plurality of upper electrodes. The method of claim 12, And the step S1 and the step S2 are alternately repeated. 14. The method according to any one of claims 11 to 13, And applying a display voltage to the upper electrode and the lower electrode. An electronic paper display device comprising a plurality of cells including a plurality of particles, a plurality of lower electrodes formed at predetermined intervals, an upper electrode facing the lower electrode, and a voltage driver for applying a voltage to the lower electrodes. In the driving method, (S1) before the display voltage is applied, the voltage driver applying a voltage having opposite polarities between adjacent electrodes to the plurality of lower electrodes; E-paper display device driving method comprising a. The method of claim 15, (S2) The method of driving the electronic paper display device, further comprising the step of applying a voltage having a polarity opposite to the step S1 to the plurality of lower electrodes. The method of claim 16, And the step S1 and the step S2 are alternately repeated. The method according to any one of claims 15 to 17, And applying a display voltage to the upper electrode and the lower electrode.

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