Reflective custom color display device

Abstract

The present invention relates to a panel structure for a reflective custom color display device based on an electrophoresis technology and a method for controlling the same, and more particularly, to a panel structure for a reflective display device and a method for controlling the same, according to the present invention, various colors can be easily realized by combining electrophoretic particles having unique colors without a complicated manufacturing process, an electrically complicated driving method is not required, and stable color reproducibility can be ensured when driving repeatedly.

Description

Technical Field

[0001] The present invention relates to a reflective custom color display device using electrophoresis technology and a method for controlling the same, and more specifically, to a reflective custom color display device and a method for controlling the same, which can be easily implemented by combining electrophoretic particles with unique colors without a complicated manufacturing process, and does not require a complicated electric driving method, and ensures stable color reproducibility when repeatedly driven. Background Art

[0002] A display device based on the electrophoresis technology is a reflective display device that displays colors or information using a phenomenon in which particles move toward electrodes to which a voltage having a polarity opposite to that of the charge of the particles is applied when an electric field is generated by a voltage applied from the outside. Electrophoretic display devices can be classified into a type in which a medium through which positively charged particles or negatively charged particles move is air or a fluid.

[0003] In particular, in an electrophoretic display device in which the medium is a fluid, methods for achieving specific colors may include: i) a method for displaying various colors by setting a color filter on the upper part of the display device, ii) a method for displaying colors using colored fluids, and iii) a method for displaying colors using the colors of electrophoretic particles.

[0004] i) In the case of the color filter method, the driving method is simple, but due to the separate process and configuration of the display device, optical characteristics such as reflectivity and contrast are deteriorated, and there are problems such as a relatively complicated manufacturing process and high manufacturing cost, and therefore, it is currently applied only to relatively expensive e-books.

[0005] ii) In the case of a method using a colored fluid, the dye used to give the fluid a specific color is susceptible to ultraviolet rays, the dye easily changes color and has a short lifespan, a narrow operating temperature range, unstable electrical characteristics and relatively high power consumption, and is relatively weak in optical characteristics such as reflectivity and contrast, and therefore, it is a technology that is not currently used in the main market.

[0006] iii) In the case of the method using the color of the electrophoretic particles, according to the related art, two types of electrophoretic particles with different polarities and colors are used to realize two colors by changing the direction of the applied electric field, and in the case of using two or more types of particles, at least one type of electrophoretic particles is set to have a difference in threshold voltage or response time compared with other electrophoretic particles, thereby adjusting the intensity of the driving voltage and the applied time to express the color. In the case of the method using two or more types of particles having a difference in threshold voltage or response time, when compared with the color filter method, it has the advantages of a simple manufacturing method, easy processability and excellent color reproducibility. However, the driving method for independently controlling each particle is relatively very complicated, the update time for updating the color or information is relatively long, and the electric energy required for each particle movement is different, and therefore, there are many limitations in ensuring uniform color characteristics during repeated driving. In addition, the complex driving pulses applied to achieve a specific color may cause excessive flickering (screen flickering) during the color conversion process, thereby causing visual discomfort to consumers. In addition, there is a problem that the operating temperature range is relatively narrow because the deviation of the threshold voltage or response time of the particles narrows or widens according to the change of the external temperature. For this reason, in the related art, in the case of the color realization technology using color particles, there is no major restriction on the update time for information update, and it is mainly applied to electronic tags and advertising devices that can display complex information and require excellent visibility.

[0007] In the related art, electrophoretic displays are mainly used in display devices that focus on resolution, readability, and full-color realization, but recently, electrophoretic displays have begun to be applied to home appliances, furniture, and interior designs that focus on design. In the case where the electrophoretic display is applied to products that focus on design, the electrophoretic display must be able to stably and reproducibly realize unique and diverse custom colors that match the environment in which the product is used without causing visual discomfort to consumers, and performance is critical due to its characteristics of requiring a long life in relatively harsh environments compared to display devices. Therefore, in the case of products that focus on custom colors, an electrophoretic display device that has excellent color reproducibility and easy processability and can realize a color with a unique color of electrophoretic particles is relatively suitable, compared to an electrophoretic display device using a color filter and a color fluid that has poor color reproducibility and is susceptible to processability and lifespan.

[0008] The method for producing electrophoretic particles having a specific unique color includes a method for applying a functional group imparting a charge to the surface of the particles having the unique color ( Figure 3a); a method for first applying a material such as particles having a color to be realized on the surface of a mother particle having a unique color and having a size smaller than that of the mother particle and then subsequently applying a functional group ( Figure 3 b) A method for applying a functional group after dyeing the surface of the particle with a substance such as a dye ( Figure 3 c) and a method for mixing particles having different unique colors ( Figure 3 d) to achieve a specific color. Figure 3 b and Figure 3 As shown in FIG. 3 , in a method for applying a substance having a specific color on the surface of a particle, during a surface modification reaction for introducing a functional group into a mother particle to impart an electric charge to the particle, since a second material having different properties is provided on the surface of the particle, there are many restrictions on the surface modification reaction and a complicated manufacturing process may be required, and further, since there is a deviation in driving voltage and lifespan between the finally manufactured electrophoretic particles due to an unstable and unbalanced surface charge coating, there is a problem of poor color reproducibility when repeatedly operated. Figure 3 a and Figure 3 As shown in FIG. 4 , in the method for manufacturing electrophoretic particles using the unique color of the mother particle, the charged functional group can be stably applied to the mother particle in terms of manufacturing, and the particles can be reproducibly controlled. Figure 3 In the method shown in a, the number of master particles with unique colors to which functional groups are stably applied is limited, and it takes a lot of time and cost to develop and manufacture color particles for achieving various customized colors required by consumers, and therefore, as shown in FIG. Figure 3 As shown in FIG. 4 , the method for realizing various colors requested by consumers by adjusting the combination and mixing ratio of particles having different unique colors in the existing master particles has many advantages in terms of development cycle, manufacturing cost, manufacturing time, etc.

[0009] Figure 4 a to Figure 4 c is a cross-sectional view showing the structure of a conventional display device that realizes a specific color by using electrophoretic particles having different unique colors and threshold voltages. Figure 3 In the method of realizing a specific color by combining electrophoretic particles with different unique colors as shown in d, according to the related art, a deviation of the threshold voltage or response time of each electrophoretic particle is provided to control the intensity and time of the applied voltage, etc., so that the particles with different unique colors are electrically mixed to realize a specific custom color. However, in the method according to the related art, when Figure 4When electrophoretic particles having different colors are added as shown in , there is a problem that the driving waveform for independently controlling each particle is very complicated, thereby further increasing the update time during repeated driving and deteriorating the color reproducibility. Figure 4 As shown in b, in the process of converting colors, a color not requested by the consumer is initially realized on the display portion, and then, as shown in Figure 4 As shown in FIG. 3 , in the process of electrically moving and mixing particles, a flickering phenomenon that consumers feel visually uncomfortable may occur repeatedly for several seconds to tens of seconds, and as the direction of the applied electric field (i.e., the polarity of the applied voltage) is repeatedly changed, some of the electrophoretic particles with opposite charges may be mixed, thereby deteriorating color reproducibility. In particular, in order to electrically mix electrophoretic particles having different colors, there is a problem of increased power consumption for achieving a specific color due to the application of a short-cycle driving waveform to the display device for a relatively long time, and the lifespan may be relatively short due to repeated collisions between particles. Summary of the invention

[0010] Technical issues

[0011] An object of the present invention is to provide a reflective custom color display device and a method for controlling the same, in which a specific color is achieved by mixing a plurality of particles having different colors, wherein since the electrophoretic particles mixed to achieve the specific color have charges of the same polarity, and the charge deviation between the particles is not large, and therefore, the threshold voltage and the response time are similar, so that they move simultaneously under the same driving voltage (uniform electric field), there is no need for a process of electrically arranging and mixing the particles (such electrical arrangement and mixing directly affects unnecessary color display and flickering of the display part during the color conversion process), thereby reliably and reproducibly achieving the specific color with a relatively simple driving method.

[0012] In addition, an object of the present invention is to provide a structure of a display device and a method for controlling the same, which display device is capable of minimizing the movement of electrophoretic particles to achieve specific colors and improve the life of electrophoretic particles, reducing the update time required to change colors compared to conventional technologies, and effectively shortening the development time for achieving various specific colors and reducing manufacturing costs.

[0013] Technical Solution

[0014] The present invention provides a reflective custom color display device, comprising: an upper electrode (101) and a lower electrode (104), respectively arranged on the side surface of a substrate; and a display layer (106), comprising a fluid, wherein the fluid contains three or more types of particles and displays two or more colors through the particles, wherein any one of the colors is displayed as a first color in which two or more types of particles having the same charge polarity and threshold voltage are mixed.

[0015] Particles can have a negative, positive or neutral polarity.

[0016] The mixed color can present a colored color and an adjusted saturation according to the composition ratio of a plurality of particles having each color.

[0017] Furthermore, the second color may be displayed by including one or more types of particles having a color different from the first color and having the same threshold voltage but opposite charge polarity compared to two or more types of particles having the first color in which the color is mixed.

[0018] In addition, a third color may be displayed by further including one or more types of particles having different threshold voltages than particles displaying the first color and the second color.

[0019] In addition, a fourth color may be displayed by further including one or more types of particles having the same threshold voltage but opposite charge polarity as compared to particles displaying the third color.

[0020] In addition, two or more types of particles having the same charge polarity and threshold voltage may have a polarity of positive charge or negative charge, and the remaining particles may further include one or more types of particles having a polarity of neutral charge to display a second color.

[0021] In addition, a third color may be displayed by further including one or more types of particles having the same threshold voltage but opposite charge polarity as compared to particles displaying the first color.

[0022] In addition, a fourth color may be displayed by further including one or more types of particles having different threshold voltages compared to particles displaying the first color, the second color, and the third color.

[0023] In addition, a fifth color may be displayed by further including one or more types of particles having the same threshold voltage but opposite charge polarity as compared to particles displaying the fourth color.

[0024] In addition, a sixth color may be displayed by further including one or more types of particles having different threshold voltages compared to particles displaying the first color, the second color, the third color, the fourth color, and the fifth color.

[0025] Furthermore, a color different from the first color may be displayed by including particles having the same color as any one of the mixed particles having the first color but having a different threshold voltage or charge polarity.

[0026] In the present invention, mixed colors can be expressed by mixing two or more types of particles having different colors and the same charge polarity and the same threshold voltage, and two to eight types, two to six types, two to five types, two to four types or two to three types of particles can be mixed and used according to color and saturation.

[0027] Beneficial Effects

[0028] According to the related art, when compared to conventional technology, specific custom colors can be stably and reproducibly achieved through a relatively simple driving method without the process of electrically arranging and mixing various particles (such electrical arrangement and mixing will directly affect unnecessary color display and flickering of the display unit during the color conversion process).

[0029] Furthermore, the movement of electrophoretic particles can be minimized to achieve a specific color, the life of the electrophoretic particles can be improved, the update time required to change the color can be significantly reduced compared to the related art, and power consumption can be reduced.

[0030] Furthermore, since colors are realized without electrically mixing a plurality of particles having different colors, driving stability can be ensured even in the case of repeated driving, compared with the related art.

[0031] In addition, since complex process development is not required to achieve various customized colors, the development time can be effectively shortened and the manufacturing cost can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a cross-sectional view showing a panel structure of an electrophoretic display device, in which the medium is a transparent fluid.

[0033] Figure 2 is a cross-sectional view showing a panel structure of a conventional electrophoretic display device for color realization.

[0034] Figure 3 is a schematic diagram showing color combinations and color realizations of electrophoretic particles.

[0035] Figure 4is a cross-sectional view illustrating a structure and configuration of electrophoretic particles of a conventional electrophoretic display device that realizes a specific color by using electrophoretic particles having different unique colors and threshold voltages, and a method of realizing a specific color.

[0036] Figure 5 is a cross-sectional view showing a panel structure of a display device having a structure and arrangement of electrophoretic particles and realizing a specific color according to an embodiment of the present invention.

[0037] Figure 6 a is an image of electrophoretic particles with different colors, and Figure 6 b is through Figure 6 a. A combination of different colored particles is used to show images of electrophoretic particles of various custom colors.

[0038] Figure 7 are images demonstrating custom colors for display devices made in accordance with embodiments of the present invention.

[0039] Figure 8 a is an image demonstrating custom colors of a display device manufactured according to an embodiment of the present invention, Figure 8 b is the target custom color image, and Figure 8 c is an image demonstrating customized colors of a display device to which conventional technology having different threshold voltages is applied.

[0040] Fig. 9 is a cross-sectional view illustrating a panel structure and a control method of a display device including a configuration of electrophoretic particles according to an embodiment of the present invention.

[0041] Fig.10 is an image of a display device according to an embodiment of the present invention, in which a first color and a second color are realized by controlling various colors and saturation by combining electrophoretic particles having different colors.

[0042] Fig.11 is a cross-sectional view illustrating a structure and a control method of a display device including neutral particles according to an embodiment of the present invention.

[0043] FIG. 12 is a cross-sectional view showing a structure of a display device capable of realizing three or more colors according to an embodiment of the present invention.

[0044] Fig.13 a is a demonstration of the manufacturing and driving of the embodiment according to Fig.12a The display device experimentally produces images in three colors, and Fig.13 b is a demonstration of the manufacturing and driving of the embodiment according to Figure 12b The display device produces the results of the three-color image.

[0045] Fig.14 The demonstration is driven by a combination of Fig.12c and Fig.12d Embodiments of the display device fabricated experimentally produce images of five or more colors.

[0046] 101: first electrode (upper electrode) 102: partition wall (barrier rib)

[0047] 103: Sealing layer and conductive adhesive layer 104: Second electrode (lower electrode)

[0048] 105: Color filter 106: Display layer

[0049] 200: Color particle 201: First particle

[0050] 202: Second particle 203: Third particle

[0051] 204: The fourth particle 205: The fifth particle

[0052] 206: Sixth particle 207: Neutral particle

[0053] 301: Transparent fluid 302: Colored fluid

[0054] 303: Microcapsule 304: Binder DETAILED DESCRIPTION

[0055] Since the present invention can have various modified embodiments, preferred embodiments are shown in the drawings and described in the detailed description of the present invention. The effects and features of the present invention and their implementation methods will be explained by the embodiments described below with reference to the drawings. However, the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments set forth herein.

[0056] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. When describing with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals, and redundant descriptions thereof are omitted.

[0057] In the following embodiments, the terms first, second, etc. are not used in a limiting sense, but are used to distinguish one component from other embodiments. In addition, in the following embodiments, unless the context clearly indicates otherwise, a singular expression includes a plural expression.

[0058] In the following embodiments, terms such as “include” or “have” mean that the features or components described in the specification are present, and do not preclude the possibility that one or more other features or components may be added.

[0059] The invention relates to a reflective custom color display device using electrophoresis technology.

[0060] The present invention provides a reflective custom color display device, comprising: an upper electrode 101 and a lower electrode 104, respectively disposed on the side surface of a substrate; and a display layer 106, comprising a fluid. Here, the fluid contains three or more types of particles and displays two or more colors through the particles, and any one of the colors is displayed as a first color, and when displayed as the first color, two or more types of particles having the same charge polarity and threshold voltage are mixed.

[0061] Particles can have a negative, positive or neutral polarity.

[0062] The mixed color may present a toned color and an adjusted saturation according to the composition ratio of the plurality of particles having each color.

[0063] In addition, when compared to two or more types of particles having a first color in which the color is mixed, a second color can be displayed by including one or more types of particles having a color different from the first color and having the same threshold voltage but opposite charge polarity.

[0064] In addition, a third color may be displayed by further including one or more types of particles having different threshold voltages when compared to particles displaying the first color and the second color.

[0065] In addition, a fourth color may be displayed by further including one or more types of particles having the same threshold voltage but opposite charge polarity when compared to particles displaying the third color.

[0066] Furthermore, the charge polarity of the two or more types of particles having the same charge polarity and threshold voltage may be positive charge or negative charge, and the remaining particles may include at least one type of particles having neutral charge polarity to display a second color.

[0067] In addition, a third color may be displayed by further including one or more particles having the same threshold voltage but opposite charge polarity when compared to the particles displaying the first color.

[0068] In addition, when compared with particles displaying the first color, the second color, and the third color, a fourth color may be displayed by further including one or more types of particles having different threshold voltages.

[0069] In addition, a fifth color may be displayed by further including one or more particles having the same threshold voltage but opposite charge polarity when compared to particles displaying the fourth color.

[0070] In addition, when compared with particles displaying the first color, the second color, the third color, the fourth color, and the fifth color, a sixth color may be displayed by further including one or more types of particles having different threshold voltages.

[0071] Furthermore, a color different from the first color may be displayed by including particles having the same color as any one of the mixed particles having the first color but having a different threshold voltage or charge polarity.

[0072] Figure 5 is a cross-sectional view showing a panel structure of a reflective custom color display device according to an embodiment of the present invention.

[0073] refer to Figure 5 , an upper electrode 101 and a lower electrode 104 disposed at a position opposite to the upper electrode 101 are provided to generate an electric field. Here, one or more of the upper electrode 101 and the lower electrode 104 may be patterned, and a voltage may be applied independently to each patterned electrode. A display layer 106 provided with a transparent electrophoretic fluid 301 containing at least one type of colored electrophoretic particles may be provided between the upper electrode 101 and the lower electrode 104.

[0074] refer to Figure 5 a. When the display layer 106 is configured in the form of a plurality of cells separated by partition walls (barrier ribs) 102, a sealing layer is provided after the plurality of cells are defined by the partition walls 102 on the upper electrode to prevent leakage or escape of the fluid after the fluid containing the electrophoretic particles is injected or filled into the cells. In addition, a conductive adhesive layer 103 is provided between the sealing layer and the lower electrode 104 so that an electric field is generated in the display layer 106 by a voltage applied from the outside, and the display layer 106 and the lower electrode 104 are attached or laminated to each other. Here, when an adhesive layer performing the function of a sealing layer is applied to the conductive adhesive layer 103, a sealing layer may not be provided.

[0075] refer to Figure 5 b. When the fluid containing the electrophoretic particles is sealed in the form of microcapsules 303, the microcapsules 303 are mixed with a binder 304 to prepare a slurry, and then, the slurry containing the microcapsules 303 is applied to the upper electrode 101, and then cured or dried to form a display layer 106 having a layer of multiple microcapsules 303, and a conductive adhesive layer 103 is provided between the layer of the microcapsules 303 and the lower electrode 104.

[0076] refer to Figure 5c, the electrophoretic particles contained in the fluid have different colors. Here, the electrophoretic particle 201 realizing the first color and the plurality of electrophoretic particles 202 and 203 realizing the second color (which is a custom color) are combined with each other, and the electrophoretic particle 201 realizing the first color must be set to have a charge of a polarity opposite to the polarity of the charge of the electrophoretic particles 202 and 203 realizing the second color. In addition, the plurality of electrophoretic particles 202 and 203 having different colors realizing the second color have charges of the same polarity, and the electrophoretic particles contained in the fluid must be set so that the deviation of the charge amount is not large, so that the electrophoretic particles move toward the upper electrode or the lower electrode 104 at the same time in the same direction in a uniform electric field. That is, the threshold voltage and response time of each electrophoretic particle are set to be the same. The first electrophoretic particle 201 presenting the first color and having a charge of the opposite polarity to the electrophoretic particles 202 and 203 presenting the second color must have the same threshold voltage as the electrophoretic particles 202 and 203 presenting the second color, but may have different response times.

[0077] refer to Figure 5 c. Since the electrophoretic particle 201 presenting the first color and the electrophoretic particles 202 and 203 presenting the second color have the same driving voltage, the color conversion process will not be the same. Figure 4 Unnecessary colors appear on the display portion as in the conventional technology of b, and the electrophoretic particles 202 and 203 having different colors for realizing the second color have the same driving voltage and response time, and therefore do not need to be as Figure 4 c. Therefore, when compared with the conventional technology, since the driving method is relatively simple and the driving voltage is the same, a high-performance control system for electrically controlling the particles is not required, thereby reducing the manufacturing cost of the product to be applied, and the mixing of the first particles 201 with different charge polarities can be prevented in advance, thereby achieving excellent repeated color reproducibility. In addition, when compared with the conventional technology, color conversion without visually uncomfortable flickering is possible, the update time for realizing a custom color can be very short, and therefore, power consumption can be low, and the life of the electrophoretic particles can be greatly improved.

[0078] In addition, according to an example of a method for manufacturing particles presenting a second color (which is a custom color) by mixing electrophoretic particles, a functional group that imparts an electric charge to each particle can be stably applied to particles coated with a colored material on the surface thereof or particles having different colors so as to be set so that a specific electric charge appears on the surface of the particle, the electrophoretic particles can be mainly manufactured by dispersing in a transparent fluid 301 through another process, the mixing ratio of the particles with different colors contained in the fluid can be set by adjusting the mixing ratio of the fluid to achieve the custom color, and the particles can finally be mixed with a fluid containing electrophoretic particles that contain electric charges with opposite polarities and present a first color to manufacture electrophoretic ink capable of achieving the first color and the second color.

[0079] Optionally, the mixing ratio of particles having different colors for presenting a second color can be adjusted to shorten manufacturing time and reduce manufacturing costs so as to match the color to be achieved, the surface charge coating process can be performed in a state where the particles are mixed and then dispersed with the fluid, and the electrophoretic particles 201 presenting the first color can be additionally mixed to manufacture electrophoretic ink.

[0080] According to the technology of the present invention, electric charges can be uniformly and stably applied to the surface of particles so that particles with different unique colors have the same threshold voltage, and various custom colors can be easily achieved by combining and adjusting the mixing ratio of particles with unique colors such as CMY as the three primary colors or RGB as the complementary colors.

[0081] Figure 6 a is an image showing electrophoretic particles of different colors manufactured by applying and drying particles having unique colors to have specific charges according to an embodiment of the present invention, and Figure 6 b is an image showing electrophoretic particles of different colors manufactured by adjusting a mixing ratio of particles having different colors to have various customized colors, and then applying and drying the particles to have the same threshold voltage according to an embodiment of the present invention.

[0082] Figure 7 It is a demonstration based on Figure 5b. An image of a custom color of a display device manufactured by an embodiment of the present invention. The mixing ratio of the yellow particles and the blue particles can be adjusted to present a second color (which is a custom color), thereby setting the custom color, and the process of applying a functional group imparting a charge can be performed together so that the two particles that realize the second color have a positive charge and move at the same driving voltage. Thereafter, the electrophoretic particles presenting the second color and the white electrophoretic particles presenting the first color with a negative charge are dispersed in a transparent fluid 301 to manufacture an electrophoretic ink. Thereafter, the electrophoretic ink manufactured on a base material or substrate coated with a transparent electrode (upper electrode 101) is formed in the form of microcapsules 303, and a slurry mixed with a binder 304 is applied and dried to form a display layer 106 in the form of microcapsules 303. The display layer 106 is laminated and attached to the lower electrode 104 using a conductive adhesive layer 103 to manufacture a display device for testing, the voltage applied to the upper electrode 101 acting as a common electrode is set to 0V or a ground voltage (GND), and a voltage of -12V is applied to the lower electrode 104. As a result, as Figure 5 As shown in FIG. 1 , it is confirmed that all of the yellow electrophoretic particles and the blue electrophoretic particles having positive charges move toward the lower electrode 104, and all of the white particles having negative charges move toward the upper electrode 101 as the display portion, and the display portion has the first color, that is, white. In addition, when +12 V is applied to the lower electrode 104, as shown in FIG. Figure 5 As shown in b, it is confirmed that in a uniform electric field, white particles with negative polarity move toward the lower electrode 104, and yellow particles and blue particles with positive polarity move toward the upper electrode 101 at the same time, thereby stably realizing a second color in which two particles with different colors are mixed.

[0083] Figure 8It is an image showing the color of a display device manufactured in the form of microcapsules 303 using white electrophoretic particles with negative charge polarity to realize a first color and yellow electrophoretic particles and green electrophoretic particles with positive charge polarity to realize a second color (which is a custom color) according to an embodiment of the present invention. The target color is printed using a color printer to verify the color reproducibility, and then the electrophoretic particles are mixed to approach the target color, thereby manufacturing electrophoretic ink. Here, the particles presenting the second color applied to the display device (left) to which the technology of the present invention is applied are set to have the same threshold voltage, and the display device (right) to which conventional technology is applied is set to make the threshold voltages of the two particles different from each other. As a result, the display device to which the technology of the present invention is applied can also be operated reproducibly even when the color of the electrophoretic particles is electrically driven. However, compared with the color of the initial electrophoretic particles mixed when electrically driven, the display device using conventional technology has a large difference from the target color. Therefore, it is confirmed that the second color realized varies according to the driving method, and the color reproducibility is unstable, such as some white particles with opposite charge polarities are mixed between the yellow particles and the green particles set in the display part to realize the custom color when repeatedly driven.

[0084] refer to Fig. 9 a. To realize the second color (which is a custom color), the present invention can realize the color by combining three or more types of electrophoretic particles. Here, the polarity of the charge and the threshold voltage of the particles 202, 203 and 204 presenting the second color must be the same.

[0085] refer to Fig. 9 b. To realize the first color, the present invention can realize another customized color by combining one or more types of electrophoretic particles with different colors. Here, the polarity and threshold voltage of the charge of the particles presenting the first color must be the same, and the charge must have a polarity opposite to that of the particles presenting the second color.

[0086] refer to Fig. 9 c. The color of at least one type of particles among the particles suitable for realizing the second color may have the same color as the particles 201 for realizing the first color. Here, the charges of the particles 201 realizing the first color and the particles 202, 203, and 204 realizing the second color must have opposite polarities or different electrical driving characteristics.

[0087] refer to Fig. 9 d. The present invention can control the saturation of a color when realizing a specific custom color by combining electrophoretic particles having different colors, and the saturation of the color is realized by simultaneously using white electrophoretic particles or black electrophoretic particles that reflect or absorb light incident from the outside.

[0088] Fig.10 is based on Fig. 9 An embodiment of the present invention realizes an image of a display panel of a first color and a second color, and the color is expressed by combining the colors of particles for realizing each color.

[0089] like Fig.11 As shown in FIG. 1 , the present invention can be applied to a method for realizing a second color (which is a custom color) by mixing neutral particles 207, which are electrically neutral, have no charge or have an extremely low charge, and have a different color. Here, due to the electrical mobility of the electrophoretic particles 201 for presenting the first color, the color conversion of the display portion is realized by vertical movement and position within the display layer 106.

[0090] like Fig.11 As shown in FIG. 2 b , the present invention can apply particles 201 exhibiting a first color as neutral particles 207 , and can exhibit a second color (which is a custom color) by mixing a combination of particles 202 , 203 , and 204 .

[0091] refer to Fig.12a ,according to Fig.11 a and Fig.11 b display panel can realize three or more colors by combining multiple electrophoretic particles 201 and 202 with different colors, multiple electrophoretic particles 203 and 204 with different colors, and neutral particles 207, wherein the multiple electrophoretic particles 201 and 202 have positive or negative charges and present a first color, the multiple electrophoretic particles 203 and 204 have polarities opposite to the polarities of the electrophoretic particles presenting the first color and present a second color, and the neutral particles 207 are electrically neutral and present a third color. The electrophoretic particles 201 and 202 exhibiting the first color and the electrophoretic particles 203 and 204 exhibiting the second color must have the same driving voltage, and when the driving voltage is applied, if the driving voltage is applied for a sufficient time toward the upper electrode or the lower electrode 104 through which a voltage having a polarity opposite to the polarity of the charge of the electrophoretic particles flows, the display portion can realize the first color and the second color according to the direction of the electric field, and the electrically neutral particles 207 can be provided between the electrophoretic particles 201 and 202 realizing the first color and the electrophoretic particles 203 and 204 realizing the second color in the display layer 106. Here, if the time for applying the driving voltage is shorter than the response time required for all the electrophoretic particles realizing the first color and the second color to move toward the upper electrode and the lower electrode, or a driving voltage having a voltage less than a threshold voltage is applied, the electrophoretic particles can be provided between the neutral particles 207 and the display portion displaying the third color.

[0092] Fig.13 a is the use according to the implementation Fig.12aThe display device realizes an image of three colors. The first color and the second color are realized by combining a plurality of electrophoretic particles having different colors, and the third color is realized by using green neutral particles 207 which are electrically neutral.

[0093] like Figure 12b As shown in , the present invention can realize three or more colors by using electrophoretic particles 205 having different threshold voltages compared with electrophoretic particles 201, 202 realizing the first custom color and electrophoretic particles 203 and 204 realizing the second custom color instead of neutral particles 207. Here, all threshold voltages of the plurality of electrophoretic particles realizing the first color and realizing the second color must be the same. If the electrophoretic particles realizing the third color have a threshold voltage smaller than the threshold voltages of the electrophoretic particles realizing the first color and the second color, the third color can be presented by applying a voltage smaller than the threshold voltages of the electrophoretic particles realizing the first color and the second color.

[0094] Fig.13 b is used according to one embodiment Figure 12b The display device realizes an image of three colors. The first custom color and the second custom color are realized by combining a plurality of electrophoretic particles having different colors, and the third color is realized by using red electrophoretic particles having relatively different threshold voltages.

[0095] refer to Fig.12c , electrophoretic particles having different threshold voltages from the neutral particles 207 can be applied to the technology of the present invention to achieve four or more colors ( Fig.12a and Figure 12b of ).

[0096] refer to Fig.12d When electrophoretic particles with different threshold voltages are used compared to electrophoretic particles that realize the first color and the second color, four or more colors can be realized by adding electrophoretic particles with positive and negative charges and different colors and threshold voltages. In addition, when particles with different threshold voltages are added, the number of colors that can be realized can be increased.

[0097] Fig.14 It means that according to the implementation mode Fig.12c and Fig.12d Display devices of the present invention are combined to realize five or more colors and express images of different colors.

[0098] According to the present invention, the application Figures 5 to 14 The manufacturing process of a specific embodiment and the materials used in the process are as follows.

[0099] The display panel according to the present invention is made of a composite material phase in which solid and liquid substances are mixed.

[0100] The upper substrate may be a base film made of an optically transparent material with high transmittance such as glass or a material with high transmittance. The upper substrate may be a transparent polymer film with excellent light transmittance, and may be made of polyethersulfone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyallyl ester, polyimide, polycarbonate (PC), triacetyl cellulose (TAC), etc., but is not limited thereto.

[0101] The upper electrode 101 may be disposed on one surface of the upper substrate facing the lower substrate. The upper electrode 101 may apply the same voltage to the plurality of display layers 106. The upper electrode 101 may be a common electrode disposed in a plate shape so as to be common to the plurality of display layers 106. The upper electrode 101 may be disposed at the viewing side and may be made of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), aluminum zinc oxide (AZO), ZnO, or a transparent conductive oxide (TCO).

[0102] The fluid may include materials such as water, methanol, ethanol, propanol, butanol, propylene carbonate, toluene, benzene, hexane, chloroform, isoparaffin oil, silicone oil, ester oil, hydrocarbon oil, triethylhexyl glucoside, polydimethylsiloxane, cetyl valerate, dioctanoic acid, isopropyl myristate, and tocopheryl acetate. The fluid may include fluorescent materials, phosphorescent materials, luminescent materials, or color-changeable materials whose color properties change when energy is applied (e.g., chromophore materials, chromophore dye materials, etc.).

[0103] Microcapsules 303 can be manufactured by forming an emulsion and configuring the emulsion into a reaction process of core-shell form. A polymer precursor that can present low elasticity and rigidity properties can be used as a polymer for forming the shell of the microcapsule, and copolymers such as urea-formaldehyde, melamine-formaldehyde and methyl vinyl ether co-maleic anhydride or polymers such as gelatin, polyvinyl alcohol, polyvinyl acetate, cellulose derivatives, gum arabic, carrageenan, carboxymethyl cellulose, hydrolyzed styrene anhydride copolymers, agar, alginate, casein, albumin and cellulose phthalate can also be used, and the polymer can be controlled to be hydrophilic and hydrophobic to surround the core material, thereby forming a shell. Additives can be added to improve the stability of the emulsion. The additive can be an organic polymer with high viscosity and excellent wettability after dissolving in water, and specifically, at least one of gelatin, polyvinyl alcohol, sodium carboxymethyl cellulose, starch, hydroxyethyl cellulose, polyvinyl pyrrolidone or alginate can be used as an additive. The microcapsules can be fixed in the layer of the binder 304 at predetermined intervals so that space is defined between the microcapsules 303. Each microcapsule 303 is not in direct contact with adjacent microcapsules 303 due to the spacing.

[0104] The layer of binder 304 may include a material that is at least partially transparent in the visible light range of 380 nm to 750 nm. The layer of binder 304 may include at least one transparent polymer material selected from the group consisting of acrylic polymers, siloxane polymers, ester polymers, polyurethane polymers, amide polymers, ether polymers, fluoropolymers, and rubbers. In addition, the layer of binder 304 may include fluorescent materials, phosphorescent materials, luminescent materials, etc., or materials whose color characteristics change with the application of energy (e.g., thermochromic pigment materials, thermochromic dye materials, etc.).

[0105] Adhesive layer (or adhesive layer) can include semiconductor or anisotropic conductive material. Adhesive layer can include carbon particles, gold particles, aluminum particles, platinum particles, silver particles, plated polymer balls, plated glass balls or ITO particles, or can include conductive polymers such as polyacetylene, polyaniline, polypyrrole, P-DOT or polythiophene. Adhesive layer (or adhesive layer) can be formed using pressure-sensitive adhesive (PSA). Pressure-sensitive adhesive can be used to prevent the change of the optical properties of the assembly member, and can use materials that do not need to be used for high-temperature processes for curing or drying during bonding. For example, adhesive layer (or adhesive layer) can use suitable polymers such as acrylic polymers, siloxane polymers, polyesters, polyurethanes, polyethers or synthetic rubbers. Adhesive layer (or pressure-sensitive adhesive layer) can use high elasticity silicone rubber, etc., which not only has a simple adhesive layer (or pressure-sensitive adhesive layer) function, but also plays the role of a cushion to mitigate impact. Adhesive layer (or adhesive layer) can be curable by energy (for example, heat or UV, etc.) or can be non-curable.

[0106] For example, the bonding layer (or adhesion layer) may be an insulating organic material and may be made of polyethersulfone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyallyl ester, polyimide, polycarbonate (PC), triacetate cellulose (TAC), etc., but is not limited thereto.

[0107] The lower substrate may be made of a variety of materials such as plastic or metal instead of an optically transparent material. As an example, the lower substrate may include a metal foil containing a metal such as silver or aluminum or a plastic film having a rear surface coated with a metal layer.

[0108] The lower substrate may be a flexible substrate that can be bent, folded or curled. In this case, the lower substrate may be a flexible printed circuit board. However, the present invention is not limited thereto, and the lower substrate may be made of a phenol-based synthetic resin or an epoxy-based synthetic resin. In this case, the lower substrate may be a rigid printed circuit board. The lower electrode 104 may be disposed on one surface of the lower substrate. The lower electrode 104 may apply the same or different voltages to a plurality of microcapsules 303.

[0109] The lower electrode 104 may be provided as a single layer structure of copper, aluminum, indium tin oxide (ITO), or indium zinc oxide (IZO) or a multilayer structure in which nickel or gold is further laminated on the material of copper, aluminum, ITO, or IZO.

[0110] The above disclosed descriptions should be considered as exemplary and not restrictive, and the appended claims are intended to cover all such modifications, enhancements and other embodiments that fall within the true spirit and scope of the present invention. Therefore, the embodiments disclosed in this specification should be considered as exemplary and not restrictive, and the spirit and scope of the present invention are not limited to the aforementioned embodiments. Therefore, the scope of the present invention is not limited by the detailed description of the present invention but by the appended claims, and all differences within the scope will be interpreted as included in the present invention.

[0111] Industrial Applicability

[0112] According to the present invention, a color display device capable of stably and reproducibly realizing a specific color by mixing particles having different colors using a simple driving method can be manufactured, and thus has industrial applicability.

Claims

1. A reflective custom color display device, comprising: An upper electrode (101) and a lower electrode (104) are respectively arranged on the side surfaces of the substrate; as well as A display layer (106) comprising a fluid, wherein the fluid contains three or more types of particles and two or more colors are displayed by the particles, Among them, any one of the colors is displayed as a first color, and when displayed as the first color, two or more types of particles having the same charge polarity and threshold voltage are mixed.

2. The reflective custom color display device according to claim 1, wherein: The particles have a negative, positive or neutral polarity.

3. The reflective custom color display device according to claim 1, wherein: The mixed color exhibits a colored color and an adjusted saturation according to a composition ratio of the plurality of particles having each color.

4. The reflective custom color display device according to claim 1, wherein: The second color is displayed by including one or more types of particles having a color different from the first color and having the same threshold voltage but opposite charge polarity compared to the two or more types of particles having the first color in which the colors are mixed.

5. The reflective custom color display device according to claim 4, wherein: A third color is displayed by further including one or more types of particles having a different threshold voltage than the particles displaying the first color and the second color.

6. The reflective custom color display device according to claim 5, wherein: A fourth color is displayed by further including one or more types of particles having the same threshold voltage but opposite charge polarity as compared to the particles displaying the third color.

7. The reflective custom color display device according to claim 1, wherein: The two or more types of particles having the same charge polarity and threshold voltage have a polarity of positive charge or negative charge, and the remaining particles further include one or more types of particles having a polarity of neutral charge to display a second color.

8. The reflective custom color display device according to claim 7, wherein: A third color is displayed by further including one or more types of particles having the same threshold voltage but opposite charge polarity as compared to the particles displaying the first color.

9. The reflective custom color display device according to claim 8, wherein: A fourth color is displayed by further including one or more types of particles having a different threshold voltage than the particles displaying the first color, the second color, and the third color.

10. The reflective custom color display device according to claim 9, wherein: A fifth color is displayed by further including one or more types of particles having the same threshold voltage but opposite charge polarity as compared to the particles displaying the fourth color.

11. The reflective custom color display device according to claim 10, wherein: A sixth color is displayed by further including one or more types of particles having different threshold voltages compared to the particles displaying the first color, the second color, the third color, the fourth color, and the fifth color.

12. The reflective custom color display device according to claim 1, wherein: A color different from the first color is displayed by including the particles having the same color as any one of the mixed particles having the first color but having a different threshold voltage or charge polarity.

13. A method for driving a reflective custom color display device, the reflective custom color display device comprising an upper electrode (101) and a lower electrode (104) respectively arranged on a side surface of a substrate and a display layer (106) comprising a fluid, in, The fluid contains three or more types of particles and two or more colors are displayed by the particles, and Any one of the colors is displayed as a first color, and when displayed as the first color, two or more types of particles having the same charge polarity and threshold voltage are mixed.

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