KR102597057B1 - Optical characteristics color-tunable device, and manufacturing method and control method - Google Patents

Abstract

A color variable element and its manufacturing method and control method are disclosed. The color variable element includes a first electrode, a second electrode, and an electrophoresis layer located between the first electrode and the second electrode, and the electrophoresis layer includes first plate-shaped particles coated with an electric charge and a dispersion medium. The color variable element can control the position of the first particle using voltage intensity and control the rotation angle of the first particle using a pulse signal.

Description

Optical characteristics color-tunable device, and manufacturing method and control method}

Embodiments of the present invention relate to color-variable devices, and more specifically, to devices whose colors change by electric fields and methods of manufacturing and controlling the same.

When a magnetic field is applied, the particles move along the magnetic field, and as a result, the wavelength of the light reflected by the particles changes, so there are materials whose color changes. Registered Patent Publication No. 10-2187266, 'Method for manufacturing a counterfeit and tamper prevention device', includes first particles and second particles, and when an external magnetic field is applied, the second particles move, and the movement of the second particles causes 1 A structure is disclosed in which particles are moved and the color, etc., changes reversibly. However, since the color of the conventional color changing device is changed by a magnetic field, the moving particles are limited to magnetic materials, so there are limitations in realizing various colors.

The technical problem to be achieved by the embodiments of the present invention is to provide color changeability in which there is no limitation on the type of particles used to implement color and the color or reflection characteristics can be varied in various ways by variously controlling the position and angle of the particles through an electric field. The purpose is to provide devices and their manufacturing methods and control methods.

In order to achieve the above technical problem, an example of a color variable device according to an embodiment of the present invention includes a first electrode; second electrode; and an electrophoresis layer located between the first electrode and the second electrode, wherein the electrophoresis layer includes: first plate-shaped particles coated with electric charges; and a dispersion medium.

An example of a method for controlling a color variable device according to an embodiment of the present invention to achieve the above technical problem is a method for controlling a color variable device including plate-shaped first particles coated with electric charges, wherein the voltage intensity Controlling the position of the first particle using; and controlling the rotation angle of the first particle using a pulse signal.

An example of a method for manufacturing a color variable element according to an embodiment of the present invention to achieve the above technical problem includes generating first particles by coating flake particles with a charged material; generating an electrophoretic material in which the first particles are dispersed; and forming an electrophoretic layer composed of the electrophoretic material between the first electrode and the second electrode.

According to an embodiment of the present invention, since charge-coated particles are used, there is no limitation on the material of the particles themselves, so particles with various colors or reflective characteristics can be used. In addition, plate-shaped particles can be used to achieve not only various colors but also various reflective characteristics. The color variable element of this embodiment can be applied to various fields that utilize the color variable effect, such as display devices and forgery devices.

1 is a diagram showing the structure of an example of a color variable element according to an embodiment of the present invention;
Figure 2 is a diagram showing an example structure of a particle moving by an electric field according to an embodiment of the present invention;
Figure 3 is a diagram showing an example of a method for controlling a color variable element according to an embodiment of the present invention;
Figure 4 is a diagram showing an example of color change according to the rotation angle of the color variable element according to an embodiment of the present invention;
Figure 5 is a diagram showing an example of a change in reflection characteristics according to a change in the position of a color variable element according to an embodiment of the present invention;
Figures 6 and 7 are diagrams showing an example of a structure for maintaining a gap in the electrophoresis layer of a color variable device according to an embodiment of the present invention.
Figure 8 is a diagram showing the structure of another example of a color variable element according to an embodiment of the present invention, and
Figure 9 is a diagram showing an example of a method of manufacturing a color variable element according to an embodiment of the present invention.

Hereinafter, the color variable element, its manufacturing method, and its control method according to an embodiment of the present invention will be examined in detail with reference to the attached drawings.

1 is a diagram showing the structure of an example of a color variable element according to an embodiment of the present invention.

Referring to FIG. 1, the color variable element 100 includes a first electrode 110, a second electrode 120, and an electrophoretic layer 130. The electrophoresis layer 130 includes first particles 140 and a dispersion medium 150.

The first electrode 110 and the second electrode 120 are planar front electrodes and are formed to face each other. The first electrode 110 and/or the second electrode 120 may be implemented with metal or ITO (Indium Tin Oxide). Additionally, the first electrode 110 and/or the second electrode 120 may be implemented with a glass or film material. In one embodiment, the first electrode 110 and the second electrode 120 may be implemented as transparent electrodes made of transparent material. In another example, the first electrode 110 may be implemented as a transparent electrode, and the second electrode 120 may be implemented as an opaque electrode. Or, conversely, the first electrode 110 may be implemented as an opaque electrode and the second electrode 120 may be implemented as a transparent electrode. Alternatively, it can be implemented as at least one translucent electrode among the first electrode 110 and the second electrode 120. In addition, the transparency of each electrode 110 and 120 can be varied depending on the embodiment.

The electrophoretic layer 130 is located between the first electrode 110 and the second electrode 120. The first particles 140 of the electrophoresis layer 130 are particles with electric charges that enable movement and/or rotation when an electric field is applied.

In one embodiment, the first particle 140 itself may be composed of a material with an electric charge. However, e-ink (electronic ink), which can move by an electric field, has a circular shape, so it can implement color changes through movement, but has limitations in displaying optical characteristics (e.g., reflection effect, sparkle effect, etc.). there is.

In this embodiment, the first particles 140 are implemented in a plate shape to have optical properties. The plate-shaped first particle 140 may exhibit optical properties such as a reflection effect or a sparkle effect due to light reflected from the surface. In addition, the plate-shaped first particles must be charged with a (+) or (-) charge so that they move and/or rotate by an electric field to change color and/or exhibit optical properties. However, although existing charged liquid materials (e.g., e-ink, etc.) can create circular particles, it is difficult to implement them into a plate-shaped structure. Accordingly, in this embodiment, the plate-shaped first particles 140 are realized by coating flake particles with electric charges. The structure of the first particle 140 is reviewed again in FIG. 2.

The dispersion medium 150 may be implemented with various materials such as a transparent solvent, a colored solvent, or a colored pigment dispersion. In one embodiment, the specific gravity of the first particles 140 and the dispersion medium 150 may be the same within a predefined error range so that the first particles 140 are dispersed in the electrophoresis layer.

When an electric field is applied, the first particles 140 move and/or rotate in the dispersion medium 150. An electric field can be formed in the electrophoresis layer by applying voltage to the first electrode 110 and the second electrode 120. Depending on the intensity of the applied voltage, the moving speed and/or moving position of the first particle 140 can be controlled. The rotation angle of the first particle 140 can be controlled through a pulse signal. Since the first particle 140 is of a thin plate shape, various reflection effects and sparkling effects on the surface may appear depending on the movement position and/or rotation angle of the first particle 140. The method of controlling the voltage driving of the first particle 140 is reviewed again in FIG. 3. In addition, the color change and optical characteristic change due to movement and/or rotation of the first particle are examined again in FIGS. 4 and 5.

Figure 2 is a diagram showing the structure of an example of a particle moving by an electric field according to an embodiment of the present invention.

Referring to Figures 1 and 2, the first particles 140 present in the electrophoresis layer 130 are manufactured by coating flake particles 200 with charges. The flake particles 200 may be in the form of a thin plate that can exhibit a reflection or sparkle effect by the surface. For example, the flake particles 200 are particles whose color or reflected light changes depending on the angle of incident light on at least one side, particles on which at least one side exhibits mirror characteristics, or particles on which at least one side exhibits metallic luster characteristics. , or it may be a particle that displays one color or has two sides of different colors.

The flake particles 200 can be made of various materials with desired colors and desired optical properties. In this embodiment, the movement of the first particles is controlled through an electric field rather than a magnetic field, so the flake particles do not need to be a material such as a magnetic material that can move by a magnetic field. Additionally, since the first particles 140 are created by coating the flake particles 200 with electric charges, the flake particles themselves do not need to be limited to materials with electric charges. Therefore, since the flake particles 200 of this embodiment are not limited to a specific material, they can implement colors (e.g., gold, silver, etc.) that could not be achieved using existing pigments or achieve desired reflective characteristics (glitter effect or mirror effect). etc.) may be a material that can be implemented. In one embodiment, the first particle 140 may have a horizontal length of 5 to 50 μm.

The surface of the flake particle 200 is coated with a charged material so that the flake particle 200 can move and/or rotate when an electric field is applied. This embodiment shows an example of coating the surface of the flake particles 200 with a material having negative ions, but the surface of the flake particles 200 may be coated with a material having positive ions. Since the method of coating the flake particles 200 with a charged material is already widely known, a description of the coating method itself will be omitted. This embodiment can use various conventional materials with electric charges and various coating methods, and is not limited to a specific material or a specific coating method.

In another example, depending on the type of flake particle 200, coating of a charged material may be difficult. In this case, the flake particles 200 may be coated with an inorganic material 210 or an organic material 220 and then a charged material may be coated on the flake particles 200.

Figure 3 is a diagram illustrating an example of a method for controlling a color variable element according to an embodiment of the present invention.

Referring to Figures 1 and 3, the first particles 140 of the electrophoretic layer 130 of the color variable element 100 move and/or rotate by application of an electric field. For example, the control device (not shown) of the color variable element 100 controls the direction, voltage intensity, pulse voltage, etc. of the voltage applied to the first electrode 110 and the second electrode 120 to control the electrophoresis layer ( The movement and/or rotation of the first particle 140 is controlled by changing the characteristics of the electric field applied to 130).

In one embodiment, the movement direction of the first particle 140 can be controlled (302) by controlling the voltage direction (300). For example, if the first particle 140 is a particle with a (-) charge and a (+) voltage is applied to the first electrode 110 and a (-) voltage is applied to the second electrode 120, the first particle (140) moves in the downward direction of the electrophoresis layer 130, and when the direction of the voltage applied to the first electrode 110 and the second electrode 120 is reversed, the second particle 140 is moved to the electrophoresis layer. You can move in the upward direction of (130).

In another embodiment, the movement position of the first particle can be controlled (312) by controlling the voltage intensity (310). When voltage is applied between the first electrode 110 and the second electrode 120 for a certain period of time (e.g., several ms, etc.), the larger the magnitude of the applied voltage, the longer the movement distance of the first particle 140 may be. there is.

As another example, the rotation angle of the first particle may be controlled (eg, PWM (Pulse Width Modulation) control) 322 through the pulse signal 320. In this embodiment, the property of the first particle to rotate when a pulse voltage is applied was identified, and the rotation angle of the first particle 140 is controlled through this. The pulse width and size of the pulse voltage for control may be experimentally defined in advance depending on the size or type of the first particle 140. After rotating the first particle 140 by applying a pulse voltage, when DC voltage is applied again for a certain period of time, the first particle 140 moves according to the DC voltage and its flat surface moves in the vertical direction of the electric field (i.e., Figure 1 are rearranged horizontally. That is, the first particle 140 returns to its original state without being rotated. Therefore, the position and rotation angle of the first particle 140 can be controlled through pulse voltage and DC voltage.

Figure 4 is a diagram showing an example of color change according to the rotation angle of a color variable element according to an embodiment of the present invention.

Referring to FIG. 4, when a pulse voltage is applied to the first electrode 110 and the second electrode 120, a change in the electric field according to the pulse voltage occurs in the electrophoresis layer 130, and accordingly, the first particles ( 140) rotates. The rotation angle of the first particle 140 may vary depending on the magnitude of the pulse voltage or the time for which the pulse voltage is applied (410, 420). Additionally, when a pulse voltage is applied, the first particle 140 may move upward or downward. For example, when a (+) pulse voltage is applied, the first particle 140 moves upward and rotates in the first direction, and when a (-) pulse voltage is applied, the first particle 140 moves downward and rotates in the first direction. It can rotate in a second direction (opposite direction to the first direction).

Depending on the rotation angle of the first particle 140, optical characteristics appearing on the surface of the first particle 140 may vary. For example, if the dispersion medium 150 is black and the first particles 140 are randomly dispersed in the electrophoresis layer 400, the color variable element 100 may appear black. When a pulse voltage is applied and the first particle 140 moves toward the second electrode 120 and rotates clockwise (410) or counterclockwise (420), light incident from the second electrode 120 is reflected by the surface of the first particle 140 and may exhibit a sparkling effect along with the color of the first particle 140. If the first particle 140 is diamond-shaped, the shape of light reflection from the first particle 140 is different depending on the clockwise rotation 410 or counterclockwise rotation 420 of the first particle 140, so that the optical Characteristics (reflection effect or sparkle effect, etc.) may appear differently.

Figure 5 is a diagram showing an example of a change in reflection characteristics according to a change in the position of a color variable element according to an embodiment of the present invention.

Referring to FIG. 5, when DC voltage is applied through the first electrode 110 and the second electrode 120, the first particles 140 are moved to the top or bottom of the electrophoresis layer 130 depending on the voltage direction and voltage magnitude. Move downward. The color of the color variable element 100 may vary depending on the movement position of the first particle. For example, if the dispersion medium 150 is black and the first particles 140 are located on the first electrode side (500), the color variable element 100 displays black color. When DC voltage is applied to move the first particle 140 to 2/3 of the electrophoresis layer (510), the color variable element 100 moves the first particle 140 by the light reflected by the first particle 140. Some colors of (140) appear. When the first particle 140 is completely moved toward the second electrode 120 (520), the color of the first particle 140 appears clearly on the color variable element 100. In other words, the color displayed by the color variable element 100 may vary depending on where the first particle 140 is located in the electrophoresis layer 130. For example, if the dispersion medium 150 has a certain color, the ratio of the light reflected by the dispersion medium 150 and the light reflected by the first particles 140 varies depending on the position of the first particles 140. The color varies depending on the

Figures 6 and 7 are diagrams showing an example of a structure for maintaining a gap in the electrophoresis layer of a color variable device according to an embodiment of the present invention.

Referring to FIG. 6, when the color variable element 600 is manufactured in the form of a film, it may include a capsule 610 to maintain the gap of the electrophoresis layer 130. The first particles 140 and the dispersion medium 150 of the electrophoresis layer 130 exist within a plurality of capsules 610.

Referring to FIG. 7, the color variable element 700 includes a partition 710 to maintain a gap in the electrophoresis layer. The first particles 140 and the dispersion medium 150 of the electrophoresis layer 130 exist in the space between each partition 710.

Figure 8 is a diagram showing the structure of another example of a color variable element according to an embodiment of the present invention.

Referring to FIG. 8 , the color variable element 800 includes a first electrode 110, a second electrode 120, first particles 140, a dispersion medium 150, and second particles 810. The color variable element 800 of this embodiment further includes second particles 810 compared to the color variable element 100 shown in FIG. 1, and the remaining configuration is the same as that of FIG. 1.

The second particle 810 is a circular particle that is not affected by the electric field. For example, the dispersion medium 150 may be a transparent material, and the second particles 810 may be colored particles. For example, the second particles 810 may be implemented as a colored solvent or a colored pigment dispersion.

Figure 9 is a diagram showing an example of a method of manufacturing a color variable element according to an embodiment of the present invention.

Referring to FIGS. 1, 2, and 9 together, first particles 140 are generated by coating flake particles 200 with a charged material (S900). A material with a charge can be coated directly on the flake particles 200, or an inorganic material 210 or an organic material 220 can be coated on the flake particles 200, and then the material with a charge can be coated thereon. An example of generating the first particles 140 using charge coating is shown in FIG. 2.

An electrophoretic material is generated by mixing the first particles 140 and the dispersion medium 150 (S910). The dispersion medium 150 may be a transparent material or a colored material. In another example, as shown in FIG. 8, an electrophoretic material further including second particles 810 may be generated in the dispersion medium 150.

An electrophoretic layer 130 composed of an electrophoretic material is formed between the first electrode 110 and the second electrode 120 (S920). In one embodiment, in order to form a gap between the first electrode 110 and the second electrode 120, a capsule 610 containing an electrophoretic material is created as shown in FIG. 6, and electrophoresis is performed using the capsule 610. Layer 130 may be implemented. In another embodiment, as shown in FIG. 7, a partition wall 710 is formed between the first electrode 110 and the second electrode 120, and then the space between the partition walls 710 is filled with an electrophoretic material to form an electrophoresis layer ( 130) can be formed.

So far, the present invention has been examined focusing on its preferred embodiments. A person skilled in the art to which the present invention pertains will understand that the present invention may be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative rather than a restrictive perspective. The scope of the present invention is indicated in the claims rather than the foregoing description, and all differences within the equivalent scope should be construed as being included in the present invention.

110: first electrode 120: second electrode
130: electrophoresis layer 140: first particle
150: dispersion medium

Claims (12)

first electrode;
second electrode; and
An electrophoresis layer located between the first electrode and the second electrode,
The electrophoresis layer is,
Plate-shaped first particles coated with electric charges to enable movement and/or rotation when an electric field is applied;
a second colored, circular particle that is unaffected by electric fields; and
Contains a dispersion medium;
The first particle is a color variable element characterized in that the flake particle is coated with an inorganic or organic material and then coated with a charged material. delete According to clause 1,
A color variable element wherein the first particles and the dispersion medium have different colors. According to clause 1,
A color variable element, characterized in that the horizontal length of the first particle is 5 to 50㎛. According to clause 1,
A color variable device, characterized in that the dispersion medium is a colored solvent or a colored pigment dispersion. delete The method of claim 1, wherein the first particle is:
The direction of movement is controlled by the voltage direction,
The position is controlled by the voltage intensity,
A color variable element whose rotation angle is controlled by a pulse signal. The method of claim 1, wherein the electrophoresis layer is:
A color variable element further comprising a partition for maintaining a gap between the first electrode and the second electrode. The method of claim 1, wherein the electrophoresis layer is:
It further includes a capsule to maintain the gap between the first electrode and the second electrode,
The color variable element, characterized in that the first particles and the dispersion medium are present in the capsule. In the control method of the color variable element of claim 1,
Controlling the position of the first particle using voltage intensity; and
A control method comprising: controlling the rotation angle of the first particle using a pulse signal. Generating first particles by coating flake particles with a charged material so that they can move and/or rotate when an electric field is applied;
generating an electrophoretic material in which circular second particles that are colored and unaffected by an electric field and the first particles are dispersed; and
Comprising: forming an electrophoretic layer composed of the electrophoretic material between the first electrode and the second electrode,
The step of generating the first particle is,
First coating the flake particles with an inorganic or organic material; and
A method of manufacturing a color variable element comprising a second coating of a charged material on the inorganic or organic material.
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