KR102044257B1 - Magnetophoretic Display - Google Patents

Abstract

Herein is a first substrate; Second substrate; And a display layer provided between the first substrate and the second substrate.
The display layer may include a plurality of microcapsules including light absorbing magnetic particles, light reflecting nonmagnetic particles, and a dispersion medium; Or a plurality of pixels separated by a partition including light absorbing magnetic particles, light reflecting nonmagnetic particles, and a dispersion medium,
At least one of the light-absorbing magnetic particles and the light-reflective nonmagnetic particles provides a magnetophoretic display device in which a surface is modified with a fluorine-based compound.

Description

Magnetophoretic Display {Magnetophoretic Display}

The present invention provides a magnetophoretic display device.

The magnetophoretic display can repeatedly perform recording and erasing, and does not require a separate power.

The magnetophoretic display device can write using a magnetic recording medium and can erase writing using a magnetic erasing medium. Specifically, black magnetic particles move closer to the display surface by the recording medium to form a series of display images, and the black medium particles move away from the display surface by the erasing medium, thereby removing the display image. .

In the case of the magnetophoretic display device, the dispersibility of the black particles and the white particles and the mobility of the black particles can be important factors in determining the performance of the magnetophoretic display device. There is a need for research that can realize a high contrast ratio.

Japanese Publication: 2002-148665 Japanese Registered Publication: 1996-007532

An object of the present invention is to provide a magnetophoretic display device having excellent contrast ratio and excellent display stability.

One embodiment of the present invention, the first substrate; Second substrate; And a display layer provided between the first substrate and the second substrate.

The display layer may include a plurality of microcapsules including light absorbing magnetic particles, light reflecting nonmagnetic particles, and a dispersion medium; Or a plurality of pixels separated by a partition including light absorbing magnetic particles, light reflecting nonmagnetic particles, and a dispersion medium,

At least one of the light absorbing magnetic particles and the light reflecting nonmagnetic particles provides a magnetophoretic display device in which a surface is modified with a fluorine compound.

The magnetophoretic display device according to an exemplary embodiment of the present invention can realize an excellent contrast ratio of black and white.

The magnetophoretic display device according to an exemplary embodiment of the present invention has excellent display stability, and the display image can be clearly maintained after writing.

The magnetophoretic display device according to an exemplary embodiment of the present invention has an advantage of enabling detailed image display.

When there is no image display, the magnetophoretic display device according to an exemplary embodiment of the present invention may exhibit a texture similar to paper due to excellent whiteness.

The magnetophoretic display device according to the exemplary embodiment of the present invention has an advantage of having excellent writing responsiveness because the moving speed of the magnetic particles is increased by the magnetic writing tool.

1 illustrates a microcapsule included in a magnetophoretic display device according to an exemplary embodiment of the present invention.
FIG. 2 illustrates that an image display of a magnetophoretic display device according to an exemplary embodiment of the present invention is implemented.
3 is a view illustrating an image display of a magnetophoretic display device according to an exemplary embodiment of the present invention.
4 is an enlarged image of the boundary between the display area and the non-display area of the magnetophoretic display device according to the first embodiment after image display.
5 is an enlarged image of the boundary between the display area and the non-display area of the magnetophoretic display device according to the second embodiment after image display.
6 is an enlarged image of the boundary between the display area and the non-display area of the magnetophoretic display device according to Comparative Example 1 after image display.
7 is an image in which the boundary between the display area and the non-display area of the magnetophoretic display device according to Comparative Example 2 after image display is enlarged.
8 is an enlarged image of the boundary between the display area and the non-display area of the magnetophoretic display device according to Comparative Example 3 after image display.
9 is an enlarged image of the boundary between the display area and the non-display area of the magnetophoretic display device according to Comparative Example 4 after image display.

In the present specification, when a part "contains" a certain component, this means that the component may further include other components, except for the case where there is no contrary description.

In addition, irrespective of the reference numerals, the same or substituted components will be given the same or similar reference numerals, and redundant description thereof will be omitted. For convenience of description, the size and shape of each component member may be exaggerated or reduced. Can be.

Hereinafter, this specification is demonstrated in detail.

One embodiment of the present invention, the first substrate; Second substrate; And a display layer provided between the first substrate and the second substrate.

The display layer may include a plurality of microcapsules including light absorbing magnetic particles, light reflecting nonmagnetic particles, and a dispersion medium; Or a plurality of pixels separated by a partition including light absorbing magnetic particles, light reflecting nonmagnetic particles, and a dispersion medium,

At least one of the light absorbing magnetic particles and the light reflecting nonmagnetic particles provides a magnetophoretic display device in which a surface is modified with a fluorine compound.

The fluorine-based compound may be modified by binding to the surface ligands of the light absorbing magnetic particles and / or the light reflecting nonmagnetic particles, thereby modifying the surface of the particles.

The fluorine-based compound may be bonded to the surfaces of the light absorbing magnetic particles and / or light reflecting nonmagnetic particles, thereby improving dispersibility and mobility of the particles. Furthermore, the fluorine-based compound may play a role in making the microcapsules with high yield.

The fluorine-based compound may prevent the light absorbing magnetic particles and / or the light reflecting nonmagnetic particles from agglomerating or sticking to the inner wall of the microcapsule, thereby preventing the whiteness of the magnetophoretic display device from being lowered. Accordingly, the magnetophoretic display device has excellent whiteness and may exhibit a texture similar to paper.

Since the light absorbing magnetic particles surface-modified with the fluorine-based compound can move at high speed without aggregation in the microcapsules, they may exhibit high responsiveness during image display or image erasing of the magnetophoretic display device.

Since the light absorbing magnetic particles and / or light reflecting nonmagnetic particles surface-modified with the fluorine-based compound do not get tangled with each other, excellent contrast ratio of black / white can be realized. In addition, the magnetophoretic display device may maintain the display image clearly after writing, and implement detailed image display.

Through this, the magnetic image display device can record and erase a clear image display, and have the advantage of enabling fast recording and erasing such as actual writing.

According to an exemplary embodiment of the present invention, the fluorine-based compound may be a perfluorinated compound. The perfluorinated compound may mean a compound containing a perfluorinated group [CF ₃ (CF ₂ ) _n (an integer greater than or equal to 1)].

According to an exemplary embodiment of the present invention, the fluorine-based compound may include one or more selected from the group consisting of a perfluorinated silane compound and a perfluorinated phosphate compound.

According to one embodiment of the present invention, the perfluorinated silane compound is selected from the group consisting of perfluorooctyl triethoxysilane, and perfluorooctyl ethyl trimethoxysilane. It may contain the above.

According to an exemplary embodiment of the present invention, the perfluorinated phosphoric acid compound is 1H, 1H, 2H, 2H-perfluoro-n-octylphosphonic acid (1H, 1H, 2H, 2H-Perfluoro-n-octylphosphonic acid), 1H , 1H, 2H, 2H-perfluoro-n-hexylphosphonic acid (1H, 1H, 2H, 2H-Perfluoro-n-hexylphosphonic acid), and 2- (perfluoroalkyl) ethyl alcohol phosphate (2- (perfluoroalkyl ) ethyl alcohol phosphate) may include one or more selected from the group consisting of.

According to one embodiment of the present invention, the particle diameter of the microcapsules may be 100 μm or more and 500 μm or less. When the particle diameter of the microcapsule is within the range, the magnetic image display device can record and erase a clear image display, and can realize a high contrast ratio of black and white when displaying an image. In addition, if the particle size of the microcapsules is less than 100 ㎛ can not obtain a sufficient whiteness, if it exceeds 350 ㎛ may cause a problem that the magnetic particles can not follow the writing speed.

According to an exemplary embodiment of the present invention, the thickness of the display layer may be 150 μm or more and 550 μm or less, specifically 200 μm or more and 400 μm or less. When the thickness of the display layer is within the range, the display layer may implement excellent contrast ratio of black and white, and may implement a thin magnetophoretic display device. In addition, when the thickness of the display layer is less than 150 ㎛ sufficient adhesive force between the first substrate and the second substrate can not be obtained, and if the thickness of the display layer exceeds 550 ㎛ magnetic particles do not follow the writing speed And it may be difficult to obtain a sufficient radius of curvature when the magnetic particle display device is rolled up.

According to an exemplary embodiment of the present invention, the display layer may be a plurality of microcapsules dispersed in a polymer matrix.

In addition, according to an exemplary embodiment of the present invention, the display layer may be provided with a plurality of pixels formed of a polymer partition wall.

According to the exemplary embodiment of the present invention, the light absorbing magnetic particles may have various colors such as red, black, and brown, and specifically, may be black.

According to an exemplary embodiment of the present invention, the light absorbing magnetic particles may include one or more selected from the group consisting of iron oxide, chromium dioxide, and ferrite. Specifically, the light absorbing magnetic particles may be selected from the group consisting of black iron oxide, porous iron oxide, manganese dioxide-containing iron oxide, chromium dioxide, ferrite, iron or nickel fine particles and iron-nickel alloy. More specifically, it may be a magnetic iron oxide represented by Fe ₃ O ₄ .

According to an exemplary embodiment of the present invention, the light absorbing magnetic particles may have a particle diameter of 0.1 μm or more and 10 μm or less. Specifically, the light absorbing magnetic particles may have a particle diameter of 0.1 μm or more and 7 μm or less. In addition, according to an exemplary embodiment of the present invention, the light absorbing magnetic particles may include 50% or more or 70% or more of particles having a particle diameter of 0.1 μm or more and 0.4 μm or less.

When the particle diameter of the light absorbing magnetic particles is within the range, excellent writing clarity and fast response speed may be realized.

According to the exemplary embodiment of the present invention, the light absorbing magnetic particles may be included in an amount of 0.5 wt% or more and 10 wt% or less with respect to the dispersion medium. In detail, the light absorbing magnetic particles may be included in an amount of 1 wt% or more and 5 wt% or less with respect to the dispersion medium.

When the content of the light absorbing magnetic particles is within the above range, the light absorbing magnetic particles may be clearly displayed when the image is implemented, and high whiteness may be achieved when the image is erased.

According to an exemplary embodiment of the present invention, the light reflective magnetic particles may be white.

According to the exemplary embodiment of the present invention, the light reflective nonmagnetic particles may include one or more selected from the group consisting of titanium oxide, lithopone, zincated, white lead, and zinc emulsion.

According to one embodiment of the present invention, the particle size of the light reflective nonmagnetic particles may be 0.1 μm or more and 1 μm or less. Specifically, the particle size of the light reflective nonmagnetic particles may be 0.1 μm or more and 0.5 μm or less.

When the particle diameter of the light reflective nonmagnetic particles is within the above range, the light absorbing magnetic particles do not interfere with the movement of the light absorptive magnetic particles, and excellent whiteness can be realized when the image display is erased.

According to the exemplary embodiment of the present invention, the light reflective nonmagnetic particles may be included in an amount of 5 wt% or more and 50 wt% or less with respect to the dispersion medium. Specifically, the light reflective nonmagnetic particles may be included in more than 10 wt% 40wt% with respect to the dispersion medium.

When the content of the light reflective nonmagnetic particles is within the above range, excellent whiteness can be realized, and excellent contrast ratio of black and white can be realized when displaying an image.

According to one embodiment of the present invention, the dispersion medium is a polar dispersion medium such as water, glycols; Nonpolar solvents such as organic solvents, oils and aliphatic hydrocarbons; And it may include one or more selected from the group consisting of polar solvents such as glycols and alcohols. Specifically, the dispersion medium may be an aliphatic hydrocarbon such as isoparaffin. However, the present invention is not limited thereto and may be used as long as it is generally used in the art.

According to an exemplary embodiment of the present invention, the microcapsules or the pixels may include a dispersant; Antisettling agents; Antistatic agents; And one or more additives selected from the group consisting of antioxidants.

According to one embodiment of the present invention, the dispersant is polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, anionic aliphatic ester mixture, polycarboxylic acid amine salt It may comprise one or more selected from the group consisting of, sorbitan trioate, sorbitan monolaurate and sorbitan monostearate, organic silicon. However, the present invention is not limited thereto and may be used as long as it is generally used in the art.

According to an exemplary embodiment of the present invention, the additive may be included in each of 0.1 wt% or more and 10 wt% or less with respect to the dispersion medium.

According to one embodiment of the invention, the anti-settling agent is silicic anhydride, hydrous silicic acid, sodium silicate, potassium silicate, aluminum silicate, calcium silicate, finely divided alumina and silica powder, alkylenebis-12-hydroxystearic acid amide and / or Phenylenebis-12-hydroxystearic acid amide. However, the present invention is not limited thereto and may be used as long as it is generally used in the art.

The antisettling agent, antistatic agent and antioxidant can be used as long as it is generally used in the art.

According to an exemplary embodiment of the present invention, the first substrate may be provided under the display layer, and may be a protective substrate that protects the display layer from damage. The first substrate may be a polyester resin, and specifically, may be a transparent resin or an opaque resin such as polyethylene terephthalate, polyethylene resin, polypropylene resin, vinyl chloride resin, polycarbonate, and ultraviolet curable resin. Specifically, the first substrate may be a flexible and elastic polyolefin foam or polydimethylsiloxane (PDMS). Further, the first substrate may be a paper, an aluminum foil, or a rubber layer. Furthermore, the first substrate may be a nonmagnetic substrate.

The first substrate may prevent damage to the display layer by relieving local pressure on the microcapsule or the pixel when displaying an image.

According to one embodiment of the present specification, the thickness of the first substrate may be 50 μm or more and 300 μm or less, specifically, 100 μm or more and 200 μm or less. In the thickness range, the first substrate may effectively prevent damage to the display layer.

According to an exemplary embodiment of the present invention, the second substrate may be provided on an upper surface of the display layer, and may be a surface substrate on which an image displayed on the display layer appears. The second substrate may be a substrate having a low glossiness due to an anti-glare coating on the surface opposite to the surface in contact with the display layer. In addition, the second substrate may be a transparent polyester resin. Specifically, the second substrate may be a polyethylene terephthalate film, polyethylene naphthalate film, triacetyl cellulose film, polyethylene resin film, polypropylene resin film, vinyl chloride resin film, polycarbonate film or ultraviolet curable resin film. Further, the second substrate may be a nonmagnetic substrate.

The second substrate may be provided at a position in direct contact with or adjacent to the magnetic writing tool when displaying an image, and may serve to prevent damage to the display unit by absorbing some of the pressure during displaying the image.

According to one embodiment of the present specification, the thickness of the second substrate may be 50 μm or more and 300 μm or less, specifically, 80 μm or more and 150 μm or less. In the thickness range, the second substrate may prevent the display layer from being damaged and make the image display implemented in the display unit appear well on the outside.

1 illustrates a microcapsule 100 included in a magnetophoretic display device according to an exemplary embodiment of the present invention. Specifically, FIG. 1 illustrates that the light absorbing magnetic particles 200, the light reflective nonmagnetic particles 300, and the dispersion medium 400 are included in the microcapsule film 500. However, the microcapsules according to the present invention are not limited to FIG. 1 and may further include additional materials.

FIG. 2 illustrates that an image display of a magnetophoretic display device according to an exemplary embodiment of the present invention is implemented. In detail, FIG. 2 illustrates a magnetic writing device 900 including a magnetic phoretic display device including a display layer 800 including a microcapsule 100 provided between a first substrate 600 and a second substrate 700. Indicates that image recording is displayed.

3 is a view illustrating an image display of a magnetophoretic display device according to an exemplary embodiment of the present invention. In detail, FIG. 3 illustrates a magnetic phoretic display device including a display layer 800 including a pixel 110 provided between a first substrate 600 and a second substrate 700. This indicates that image recording is displayed.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention is not interpreted to be limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present invention to those skilled in the art.

[ Example  One]

(a) Preparation of Black Fluid

Iron oxide (Sigama Aldrich) was added to 1 M aqueous HCl solution and sonicated for 30 minutes to surface modification, and ethanol solution containing 0.1 M perfluorooctyl triethoxysilane was added for 30 minutes to sonicate the surface of light-absorbing magnetic particles. Treatment was carried out. Then, the resultant was washed with ethanol and dried in an oven at 130 ° C. for at least 2 hours to obtain surface treated black light absorbing magnetic particles.

2 parts by weight of fatty acid bisamide HS-Thickener 4060K (San nopco) as an antisettling agent was added to 94 parts by weight of ISOPAR-M (Exxon mobile chemical company), a dispersion medium, and then melted by a 90 degree water bath and sonication. 4 parts by weight of light-absorbing magnetic particles were added, dispersed for 24 hours using a zirconia bead mill, and filtered to obtain a black fluid.

(b) Preparation of White Fluid

Titanium oxide Ti-Pure R103 (Chemours) 25 parts by weight and 1 part by weight of dispersant KF-6038 (Shin-Etsu Chemical) were added to 74 parts by weight of ISOPAR-M (Exxon mobile chemical), a dispersion medium, for 24 hours using a zirconia bead mill. Dispersed and filtered to give a white fluid.

(c) Manufacture of magnetophoretic display

The black fluid and the white fluid prepared as described above were mixed at a ratio of 1.13: 1 and stirred for about 12 hours to obtain a magnetic particle dispersion. Furthermore, after preparing a transparent gelatin microcapsules containing the magnetic particle dispersion as a core material by the composite coacervation method, the microcapsules were mixed with a binder at a ratio of 5: 2 and coated on a PET film to display magnetophoretic display. The device was fabricated.

[ Example  2]

A magnetophoretic display device was manufactured in the same manner as in Example 1, except that 2- (perfluoroalkyl) ethyl alcohol phosphate was used for surface treatment of iron oxide.

[ Comparative example  One]

A magnetophoretic display device was manufactured in the same manner as in Example 1, except that the surface of the magnetic particles was not modified.

[ Comparative example  2]

A magnetophoretic display device was manufactured in the same manner as in Example 1, except that the magnetic particles were surface treated using hydrogen chloride (HCl).

[ Comparative example  3]

A magnetophoretic display device was manufactured in the same manner as in Example 1, except that the magnetic particles were surface treated using oleic acid.

[ Comparative example  4]

A magnetophoretic display device was manufactured in the same manner as in Example 1, except that the light absorbing magnetic particles were surface treated using a silane coupling agent (Triethoxy Caprylyl Silane).

[ Comparative example  5]

A magnetophoretic display device was manufactured in the same manner as in Example 1, except that the light absorbing magnetic particles were surface treated using a titanate coupling agent (Isopropyl Titanium Triisostearate).

[ Experimental Example ]

Whiteness before image display of the magnetophoretic display devices according to Examples 1 and 2 and Comparative Examples 1 to 5 was measured. In addition, the results of experiments on the contrast ratio, writing line width, black reflectivity, and display stability of black / white after image display using the magnetic writing tool according to Examples 1 and 2 and Comparative Examples 1 to 5 were performed. Is shown in Table 1 below.

4 and 5 respectively show an enlarged image of the boundary between the display area and the non-display area of the magnetophoretic display device according to the first and second embodiments after the image display. 6 to 9 each show an enlarged image of the boundary between the display area and the non-display area of the magnetophoretic display device according to Comparative Examples 1 to 4 after image display.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Surface treatment Perfluorooctyl triethoxysilane 2- (perfluorohexyl) ethyl alcohol phosphate X HCl oleic acid Triethoxy Caprylyl Silane Isopropyl Titanium Triisostearate Whiteness
(%) 59.7 75.88 61.5 47.8 54.4 77.39 70.23 Contrast Ratio 2.6: 1 4.2: 1 1.7: 1 2.1: 1 2.4: 1 2.3: 1 2.7: 1 Writing line width
(Mm) 0.4 ~ 0.8 0.4 ~ 0.8 0.5 to 0.8 0.4 ~ 0.8 0.4 ~ 0.8 0.6 ~ 0.8 0.6 ~ 0.8 Black reflectivity
(%) 18.1 15.74 22.8 21.1 20.6 31.45 25.32 Display stability ◎ ◎ △ ○ ○ △ ○

In the display stability of Table 1, the pixel was displayed in full black using a magnet, and after 1 hour, the presence or absence of sedimentation of the magnetic particles was visually determined. In the case of the writing line width, a line was drawn using a 0.5 mm magnetic pen. The line width of was measured with an optical microscope.

According to Table 1, it can be seen that the magnetophoretic display device according to the embodiment shows excellent display stability compared to the magnetophoretic display device according to the comparative example. In addition, the magnetophoretic display device according to the embodiment has a significantly better contrast ratio than Comparative Examples 1 to 5 and surface modified with another material that is not modified by the surface of the magnetic particles by using a fluorine-based compound. It can be seen that it is implemented. The excellent contrast ratio of the magnetophoretic display according to the embodiment can be easily identified through FIGS. 4 to 9. Furthermore, it can be seen that the magnetophoretic display device according to the embodiment realizes a lower writing degree of black reflectivity than the magnetophoretic display device according to the comparative example to enable clear writing.

100: microcapsules
110: pixels
200: light absorbing magnetic particles
300: light reflective nonmagnetic particles
400: dispersion medium
500: microcapsule membrane
600: first substrate
700: second substrate
800: display layer
900: magnetic writing tool

Claims (8)

First substrate; Second substrate; And a display layer provided between the first substrate and the second substrate.
The display layer may include a plurality of microcapsules including light absorbing magnetic particles, light reflecting nonmagnetic particles, and a dispersion medium; Or a plurality of pixels separated by a partition including light absorbing magnetic particles, light reflecting nonmagnetic particles, and a dispersion medium,
The light absorbing magnetic particle is a magnetophoretic display device modified on the surface with a perfluorinated phosphate compound.
delete delete The method according to claim 1,
The particle size of the microcapsule is 100 ~ 500 ㎛ magnetophoretic display device. The method according to claim 1,
And a thickness of the display layer is 150 µm or more and 550 µm or less. The method according to claim 1,
And the light absorbing magnetic particles include at least one selected from the group consisting of iron oxide, chromium dioxide, and ferrite. The method according to claim 1,
And the light reflective nonmagnetic particles include at least one member selected from the group consisting of titanium oxide, lithopone, zincated, white lead, and zinc emulsion. The method according to claim 1,
The microcapsules or pixels comprise a dispersant; Antisettling agents; Antistatic agents; And at least one additive selected from the group consisting of antioxidants.

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