WO2020186878A1

WO2020186878A1 - Electrophoretic display liquid and preparation method thereof and electrophoretic display

Info

Publication number: WO2020186878A1
Application number: PCT/CN2019/129203
Authority: WO
Inventors: 赖明华; 马宝光; 曾晞; 陈宇
Original assignee: 广州奥翼电子科技股份有限公司
Priority date: 2019-03-15
Filing date: 2019-12-27
Publication date: 2020-09-24
Also published as: CN109917599A

Abstract

An electrophoretic display liquid and a preparation method thereof and an electrophoretic display. The electrophoretic display liquid comprises a dispersion medium, electrophoretic particles and a charge control agent, wherein the charge control agent comprises a positive charge control agent and a negative charge control agent, the electrophoretic particles comprise at least one type of color-changing electrophoretic particle, and the color display of the color-changing electrophoretic particles in an external and posterior excitation state is different from that in a non-excited state. The electrophoretic display liquid and the preparation method thereof and the electrophoretic display have a better color display effect.

Description

Electrophoresis display liquid and preparation method thereof and electrophoresis display

Technical field

The invention belongs to the technical field of display devices, and specifically relates to an electrophoretic display liquid, a preparation method thereof, and an electrophoretic display.

Background technique

Electronic paper is a new type of paper-like display medium with memory function, light weight, and moderate curling or folding. Electronic paper is composed of multiple display micro-units. The micro-units contain electronic ink. Under the driving of an external voltage, color particles with different charges migrate to the two ends of the electrode to form a display screen. The stability of electrophoretic particles in the suspension directly determines the performance of the display micro-unit. The color particles in the dispersion medium exhibit their own charge or are suspended in a dielectric solvent, or they are charged with a corresponding charge using a charge control agent (CCA). In the traditional black and white two-color electrophoretic display technology, one or two charge control agents are commonly used to make the modified black and white particles have opposite charging properties.

With the development of technology and the upgrading of demand, the simple black and white two-color display can no longer meet the needs of the people, so color display is needed. However, in the multi-mode color electrophoresis display method, the electrophoretic display liquid system is more complicated, and the two-color particles are less charged, resulting in a phenomenon that the electrophoretic mobility of the two-color particles decreases, which limits the display performance of the electrophoretic display device.

Summary of the invention

Aiming at the shortcomings of the prior art, the present invention provides an electrophoretic display liquid with better color effects, a preparation method thereof, and an electrophoretic display.

The present invention provides an electrophoretic display liquid, comprising a dispersion medium, electrophoretic particles, and a charge control agent. The charge control agent includes at least one positive charge control agent and at least one negative charge control agent. The electrophoretic particles include at least one Color-changing electrophoretic particles, the color-changing electrophoretic particles present in an excited state under the excitation of an excitation source, and display colors different from those in the non-excited state.

Preferably, the charge control agent includes one or more of cationic surfactants, anionic surfactants, and nonionic surfactants.

Preferably, the cationic surfactant includes one or more of fatty amine salt, quaternary ammonium salt and alkyl pyridine salt; the anionic surfactant includes alkane carboxylate, alkane sulfonate, One or more of alkyl aromatic sulfonate, isopropylamine, alkylbenzene sulfonate, phosphate ester and phosphate; the nonionic surfactant includes sorbitan monoester, polyethoxylate Nonionic compounds, polybutene succinimide, maleic anhydride copolymer, vinyl pyridine copolymer, vinyl pyrrolidone copolymer, acrylic copolymer and acrylic acid-N,N-dimethylaminoethyl copolymer One or more of them.

Preferably, the color-changing electrophoretic particles include yttrium oxide, lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, ytterbium oxide, lutetium oxide One or more of scandium oxide and thulium oxide.

Preferably, the weight ratio of the positive charge control agent and the negative charge control agent is (0.1-6): (0.01-8).

Preferably, the weight ratio of the positive charge control agent and the negative charge control agent is (1-6):(0.5-3).

Preferably, the weight ratio of the positive charge control agent to the positively charged electrophoretic particles is (0.1-8): (50-120); the weight ratio of the negative charge control agent to the negatively charged electrophoretic particles is (0.01-10) : (20-150).

Preferably, the excitation source includes one or more of infrared light, ultraviolet light, temperature change, pH change, magnetic field intensity change, and electric field intensity change.

The present invention provides a method for preparing an electrophoretic display liquid, which is calculated in parts by weight and includes the following steps:

(1) Add 50-120 parts of positively charged electrophoretic particles, 0.1-8 parts of positive charge control agent, 0.01-10 parts of negative charge control agent, 20-150 parts of negatively charged electrophoretic particles, and 100-300 parts of dispersion medium.

(2) Raise the temperature to 60-100°C, shake for 24-36 hours, lower the temperature to 30-50°C, and shake for 12-40 hours to prepare an electrophoresis display solution.

The present invention also provides an electrophoretic display, which includes a transparent front plate, an electrophoretic display layer formed by the electrophoretic display liquid as described above, and a back plate from the outside to the inside. The transparent front plate and the back plate are used for displaying on the electrophoresis display. Electrical signals are applied to both ends of the layer.

The electrophoretic display liquid, the preparation method thereof, and the electrophoretic display provided by the invention have better color display effects.

Description of the drawings

The above-mentioned and other objects, features and advantages of the present invention will become clearer through more detailed description of the preferred embodiments of the present invention shown in the drawings. In all the drawings, the same reference numerals indicate the same parts, and the drawings are not drawn on the scale of the actual size deliberately, and the main point is to show the gist of the present invention.

Figure 1 is a schematic diagram of an electrophoretic display with only a negative charge control agent in a non-excited state;

Figure 2 is a schematic diagram of an electrophoretic display with only negative charge control agents in an excited state;

Figure 3 is a schematic diagram of an electrophoretic display with only a positive charge control agent in a non-excited state;

Figure 4 is a schematic diagram of an electrophoretic display with only positive charge control agents in an excited state;

FIG. 5 is a schematic diagram of an electrophoretic display provided by an embodiment of the present invention in a non-excited state;

6 is a schematic diagram of an electrophoretic display device provided by an embodiment of the present invention in an excited state;

detailed description

The technical solutions of the present invention will be further described in detail below with reference to specific examples, so that those skilled in the art can better understand and implement the present invention, but the examples cited are not intended to limit the present invention.

The embodiment of the present invention provides an electrophoretic display liquid, which includes a dispersion medium, electrophoretic particles, and a charge control agent. The charge control agent includes a positive charge control agent that positively charges electrophoretic particles and a negative charge control agent that negatively charges electrophoretic particles. The particles include at least one color-changing electrophoretic particle, and the color display of the color-changing electrophoretic particle in the post-excited state is different from that in the non-excited state.

The present invention uses two charge control agents. The two charge control agents act on positively charged particles and negatively charged particles. For example, the positive charge control agent acts on the color-changing electrophoretic particles that show white in the non-excited state, and the negative charge control agent acts on ordinary Black particles. The two kinds of particles are charged with different charges. Under the action of an electric field, the black electrophoretic particles and the color-changing electrophoretic particles migrate to the corresponding plate, and display multiple colors underneath. It can not only obtain the electrophoretic display liquid with color effect, but also ensure that the particles have a better migration rate.

In the traditional black and white two-color electrophoretic display technology, one or two charge control agents are commonly used to make the modified black and white particles have opposite chargeability. Two charge control agents that can respectively make the particles have positive and negative charges are mixed. The two-color electrophoresis display technology is not without obvious synergistic effect. However, acting in the electrophoretic display liquid of this embodiment has the effect of increasing the migration rate of electrophoretic particles, providing steric hindrance for the particles, and forming a more stable solution system. This is because the electrophoretic display liquid system in this embodiment is more complicated, and the two-color particles have a lower surface charge, which leads to a phenomenon that the electrophoretic mobility of the two-color particles decreases.

In a preferred embodiment, the charge control agent includes one or more of cationic surfactants, anionic surfactants, and nonionic surfactants. Generally speaking, the charge control agent makes the particles positively or negatively charged, such as sulfonate, which can make some particles negatively charged, but can also make other particles positively charged, depending on the surfactant And some properties between particles.

In a preferred embodiment, the negative charge control agent includes an anionic surfactant or a nonionic surfactant; the positive charge control agent includes a cationic surfactant or a nonionic surfactant.

In a preferred embodiment, cationic surfactants include one or more of fatty amine salts, quaternary ammonium salts and alkyl pyridine salts; anionic surfactants include alkane carboxylates, alkane sulfonates, and alkane sulfonates. One or more of alkyl aromatic sulfonate, isopropylamine, alkylbenzene sulfonate, phosphate and phosphate; non-ionic surfactants include sorbitan monoester, polyethoxylated non-ionic Type compound, polybutene succinimide, maleic anhydride copolymer, vinyl pyridine copolymer, vinyl pyrrolidone copolymer, acrylic copolymer and one of acrylic acid-N,N-dimethylaminoethyl copolymer Or several.

In a preferred embodiment, the color-changing electrophoretic particles include yttrium oxide, lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, ytterbium oxide, oxide One or more of lutetium, scandium oxide and thulium oxide.

In a preferred embodiment, the conditions include one or a combination of infrared light, ultraviolet light, temperature change, pH change, magnetic field intensity change, and electric field intensity change.

In a preferred embodiment, the weight ratio of the positive charge control agent and the negative charge control agent is (0.1-6): (0.01-8).

In a preferred embodiment, the weight ratio of the positive charge control agent and the negative charge control agent is (1-6):(0.5-3).

In a preferred embodiment, the weight ratio of the positive charge control agent and the negative charge control agent is (0.5-5): (1-5).

In a preferred embodiment, the weight ratio of the positive charge control agent and the negative charge control agent is (0.5-2): (0.05-5).

In a preferred embodiment, the weight ratio of the positive charge control agent to the positively charged electrophoretic particles is (0.1-8): (50-120); more preferably (1-5): (60-100).

In a preferred embodiment, the weight ratio of the negative charge control agent to the negatively charged electrophoretic particles is (0.01-10): (20-150); more preferably (1-5): (20-80).

The embodiment of the present invention also provides a method for preparing an electrophoretic display liquid, which is calculated in parts by weight and includes the following steps:

In a preferred embodiment, the positively charged particles and/or negatively charged particles are color-changing electrophoretic particles, and the color display of the color-changing electrophoretic particles in the post-excited state is different from that in the non-excited state.

In a preferred embodiment, the positive charge control agent and/or the negative charge control agent includes one or more of cationic surfactants, anionic surfactants and nonionic surfactants. The charge control agent makes the particles positively or negatively charged. For example, sulfonates can make some particles negatively charged, but it can also make other particles positively charged, depending on the difference between the surfactant and the particles. Some properties of the time.

In a preferred embodiment, the excitation source includes one or more of infrared light, ultraviolet light, temperature change, pH change, magnetic field intensity change, and electric field intensity change.

When the excitation source is ultraviolet light or infrared light, the color-changing electrophoretic particles have a photochromic material. After the ultraviolet light or infrared light excites the photochromic material, the color-changing electrophoretic particles show a different color from the non-excited state. Photochromic materials include yttrium oxide, lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, ytterbium oxide, lutetium oxide, scandium oxide and One or more of thulium oxide.

When the excitation source is a temperature change, the color-changing electrophoretic particles have a temperature-sensitive color-changing material, and the temperature-sensitive color-changing pigment is prepared by an electron transfer type organic compound system. Electron transfer type organic compound is a kind of organic coloring system with special chemical structure. At a certain temperature, the molecular structure of the organic substance changes due to electron transfer, thereby realizing a color transition.

When the excitation source is a change in the intensity of a magnetic field, the color-changing electrophoretic particles have a magneto-chromic material, such as the magneto-chromic material disclosed in the patent publication number CN106873190A.

When the excitation source changes in the intensity of the electric field, the color-changing electrophoretic particles have electrochromic materials, and the electrochromic materials are divided into inorganic electrochromic materials and organic electrochromic materials. The typical representative of the electrochromic material is tungsten trioxide.

When the excitation source is pH changes, the color-changing electrophoretic particles have pH-induced color-changing materials, such as methyl red, bromocresol green, thymol blue, phthalide, azo dyes, complexes formed by metal ions and chelate And other organic materials.

An embodiment of the present invention also provides an electrophoretic display, which includes a transparent front plate 111, an electrophoretic display layer formed by the electrophoretic display liquid described above, and a back plate 112 in order from the outside to the inside, the transparent front plate 111 and the back plate 112 Used to apply electrical signals at both ends of the electrophoretic display layer.

Referring to FIGS. 1-4, in a system containing only one charge control agent, no matter whether the color-changing electrophoretic particles 121 are in an excited state or a non-excited state, the overall display effect of the electrophoretic display is not good. Referring to FIGS. 5-6, in the system containing two charge control agents for compound use in this embodiment, no matter whether the color-changing electrophoretic particles 121 are in an excited state or a non-excited state, the overall display effect of the electrophoretic display is very good.

1 and 2, the electrophoretic display layer contains a dispersion medium 123, a color-changing electrophoretic particle 121 and an indispensable black particle 124. The color-changing electrophoretic particle 121 displays white when there is none, and the electrophoretic display layer also contains a negative charge control The negative charge control agent 122 is combined with the color-changing electrophoretic particle 121, so that the color-changing electrophoretic particle 121 is more negatively charged and has a better migration effect. However, since the black particles 124 are less positively charged, the migration effect is poor. Refer to FIG. 1. When the color-changing electrophoretic particles 121 are excited, the color-changing electrophoretic particles 121 show the state after excitation, showing blue (in the figure, the color changing effect of the particles is represented by different textures), refer to Figure 2.

Referring to FIGS. 3 and 4, the electrophoretic display layer contains a dispersion medium 123, a color-changing electrophoretic particle 121 and an indispensable black particle 124. The color-changing electrophoretic particle 121 displays white when there is none, and the electrophoretic display layer also contains positive charge control. The positive charge control agent 125 is combined with the black particles 124, which are more positively charged and have a better migration effect. The color-changing electrophoretic particles 121 are less negatively charged and have a poor migration effect, as shown in Figure 3. Below, the color-changing electrophoretic particle 121 shows the state after being excited, and shows blue, as shown in FIG. 4.

5 and 6, the electrophoretic display layer contains a dispersion medium 123, a color-changing electrophoretic particle 121, and an indispensable black particle 124, and the color-changing electrophoretic particle 121 displays white without it. The electrophoretic display layer also contains a positive charge control agent 125, which is combined with the black particles 124, which is more positively charged and has a better migration effect. The electrophoretic display layer also contains a negative charge control agent 122, which is combined with the color-changing electrophoretic particles 121, so that the color-changing electrophoretic particles 121 are more negatively charged, the migration effect is better, and the overall display effect is good. Refer to FIG. 5. Below, the color-changing electrophoretic particle 121 shows the state after being excited, and shows blue, as shown in FIG. 6.

In order to have a further understanding and understanding of the technical solution of the present invention, a few preferred embodiments are now listed for further detailed description.

Example 1

In a 500mL silk-top bottle, add 60g of black electrophoretic particles iron black, 3g of positive charge control agent for black electrophoresis particles, and 1g of negative charge control agent for white electrophoresis particles. White electrophoretic particles yttrium oxide doped europium phosphor 60g, dispersion medium 276g carbon tetrachloride, air is heated to 80°C, oscillated for 2 days, then lowered to 40°C, oscillated for 1 day, an electrophoresis display solution is prepared, and added to the electrophoresis device A multi-mode color electrophoretic display device is made.

Example 2

Add 30g of black electrophoretic particles iron black, 1.5g of positive charge control agent dodecyldimethyl tert-ammonium acetate for black electrophoresis particles, and dodecylbenzene, a negative charge control agent for white electrophoresis particles Sulfonic acid 4.5g, white electrophoretic particles yttrium oxide doped europium phosphor 90g, dispersion medium carbon tetrachloride 276g, air was heated to 80℃, oscillated for 2 days, then lowered to 40℃, oscillated for 1 day to prepare electrophoretic display liquid , Added to the electrophoresis device to make a multi-mode color electrophoresis display device.

Comparative example 1

Compared with Example 1, in Comparative Example 1, sodium lauryl sulfate was not added, and the remaining components and preparation methods were the same as Example 1.

Comparative example 2

Compared with Example 1, the europium oxide in Comparative Example 1 is titanium white, and the remaining components and preparation methods are the same as Example 1.

Comparative example 3

Compared with Example 1, the europium oxide in Comparative Example 1 is titanium white, and sodium lauryl sulfate is not added, and the remaining components and preparation methods are the same as in Example 1.

After testing, Example 1 and Example 2 have a higher particle migration rate than Comparative Example 1 in which only one charge control agent is added, and the prepared electrophoretic display has a faster response and better display effect.

Both Comparative Example 2 and Comparative Example 3 are aimed at traditional black and white particles. The electrophoretic displays made by the two comparative examples have no major changes in particle migration rate and display effect. It shows that the combination of two charge control agents has no better gain effect for other systems.

In summary, it shows that the scheme of the present invention is reasonable, and the electrophoretic particle migration rate of the system with color-changing electrophoretic particles of the scheme of the present invention can be improved by the combination of a positive charge control agent and a negative charge control agent.

The above are only the preferred embodiments of the present invention and do not limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the present invention, or directly or indirectly applied to other related technical fields, are the same. The theory is included in the scope of patent protection of the present invention.

Claims

An electrophoretic display liquid, characterized in that it comprises a dispersion medium, electrophoretic particles and a charge control agent. The charge control agent includes a positive charge control agent and a negative charge control agent. The electrophoretic particles include at least one color-changing electrophoretic particle. The color-changing electrophoretic particles present an excited state under the excitation of an excitation source, and display colors different from those in the non-excited state.
8. The electrophoretic display liquid of claim 1, wherein the charge control agent comprises one or more of cationic surfactants, anionic surfactants and nonionic surfactants.
The electrophoresis display liquid according to claim 1, wherein the cationic surfactant comprises one or more of fatty amine salt, quaternary ammonium salt and alkyl pyridine salt; and the anionic surfactant comprises One or more of alkane carboxylate, alkane sulfonate, alkyl aromatic sulfonate, isopropylamine, alkylbenzene sulfonate, phosphoric acid ester and phosphate; the non-ionic surface active Agents include sorbitan monoesters, polyethoxylated nonionic compounds, polybutene succinimide, maleic anhydride copolymer, vinyl pyridine copolymer, vinyl pyrrolidone copolymer, acrylic copolymer and acrylic acid- One or more of N,N-dimethylaminoethyl copolymers.
The electrophoretic display liquid of claim 1, wherein the color-changing electrophoretic particles comprise yttrium oxide, lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide One or more of holmium oxide, erbium oxide, ytterbium oxide, lutetium oxide, scandium oxide and thulium oxide.
8. The electrophoretic display liquid of claim 1, wherein the weight ratio of the positive charge control agent and the negative charge control agent is (0.1-6): (0.01-8).
8. The electrophoretic display liquid according to claim 7, wherein the weight ratio of the positive charge control agent and the negative charge control agent is (1-6): (0.5-3).
The electrophoretic display liquid of claim 1, wherein the weight ratio of the positive charge control agent to the positively charged electrophoretic particles is (0.1-8): (50-120); the negative charge control agent and the negative The weight ratio of the charged electrophoretic particles is (0.01-10): (20-150).
The electrophoretic display liquid according to claim 1, wherein the excitation source includes one or more of infrared light, ultraviolet light, temperature change, pH change, magnetic field intensity change, and electric field intensity change.
A preparation method of electrophoresis display fluid, characterized in that, in parts by weight, it comprises the following steps:

(1) Add 50-120 parts of positively charged electrophoretic particles, 0.1-8 parts of positive charge control agent, 0.01-10 parts of negative charge control agent, 20-150 parts of negatively charged electrophoretic particles, and 100-300 parts of dispersion medium.

(2) Raise the temperature to 60-100°C, shake for 24-36 hours, lower the temperature to 30-50°C, and shake for 12-40 hours to prepare an electrophoresis display solution.
An electrophoretic display, comprising a transparent front plate, an electrophoretic display layer formed by the electrophoretic display liquid according to any one of claims 1-8, and a back plate from the outside to the inside. The transparent front plate and the back plate are used for Electrical signals are applied to both ends of the electrophoretic display layer.