Unlock instant, AI-driven research and patent intelligence for your innovation.

Liquid for electrophoretic display and display medium and display employing it

An electrophoretic display and medium technology, applied in the field of display liquid, can solve problems such as decreased refractive index, decreased contrast, and display color mixing, and achieves high reliability, high contrast, and excellent responsiveness

Inactive Publication Date: 2008-12-17
MITSUBISHI PENCIL CO LTD
View PDF14 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, since the display liquid of the electrophoretic display device described in this patent document 1 etc. is generally dispersed in a hydrophobic and low-permittivity dispersion medium that dissolves a dye or the like, a high-refractive-index inorganic pigment such as titanium dioxide is dispersed. , so it has the following disadvantages: difficult control of dispersion stability, decrease in contrast and repeat display characteristics due to aggregation, etc., and decrease in display quality
[0021] However, in the technology described in the above-mentioned Patent Document 5, since the charged charges of different electrophoretic particles are a combination of positive and negative, an electric attraction force is generated between the particles, causing the aggregation of the particles, which has the effect of reducing the dispersion stability. Problems such as color mixing and contrast drop
[0022] In the technology described in the above-mentioned Patent Document 6, it is difficult to completely prevent the aggregation of the two types of electrophoretic particles, and there is a problem that a good contrast cannot be achieved.
[0023] And, even the slow-moving particles described in the above-mentioned Patent Document 7, when they exist near the electrodes on the display surface, may appear on the display surface due to the short moving distance. There is a problem in that it is difficult to obtain sufficient contrast without controlling the distribution of the charged charges to have different moving speeds between particles with different hues so that they do not overlap.
[0024] In the particles having voids inside described in Patent Document 8, since the dispersion medium enters the voids, etc., the refractive index of the white particles in particular decreases, making it difficult to obtain sufficient contrast.
[0025] In the case described in the above-mentioned Patent Document 9, the stability of the dispersion cannot be maintained, and the color mixing occurs in the microcapsules due to the aggregation caused by the electric attraction between the electrophoretic particles, thereby causing the problem of color mixing in the display.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Liquid for electrophoretic display and display medium and display employing it
  • Liquid for electrophoretic display and display medium and display employing it
  • Liquid for electrophoretic display and display medium and display employing it

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～19 and comparative example 1～6

[0234] (Examples 1 to 19 and Comparative Examples 1 to 6, preparation of liquid for electrophoretic display, first invention of the present invention)

[0235] The mixed compositions of the respective Examples and Comparative Examples shown in Table 1 below were dispersed for 60 minutes with a paint shaker using glass beads to prepare a liquid for electrophoretic display.

[0236] Microparticles used (A-1~A-8, B-1~B-2), dyes, dispersion medium (C-1~C-3), dispersant (D-1~D-4), alkyl poly As etheramines and the like (E-1 to E-6), the following were used.

[0237] Particle A:

[0238] A-1: ITT-2 TiO 2 CR-50 (manufactured by Nikko Chemicals Co.), titanium oxide whose surface has been treated with a titanium coupling agent, with an average particle size of about 0.4 μm

[0239] A-2: ITT-7 TiO 2 TTO-S-3 (manufactured by Sunshine Chemicals Co., Ltd.), titanium oxide particles treated with titanium coupling agent on the surface, with an average particle size of about 0.05-0.1 μm...

Embodiment 1

[0306] (1) Preparation of liquid for electrophoresis display

[0307] 100 g of the dispersion was prepared according to the mixing ratio described in Example 2 above.

[0308] (2) Microencapsulation

[0309] 200 g of a 5 wt % gelatin aqueous solution and 200 g of a 5 wt % gum arabic solution were mixed with stirring, the temperature was raised to 50° C., and the pH of the solution was adjusted to 9.0 using an aqueous sodium hydroxide solution. The dispersion liquid for electrophoretic display of (1) above was added to this aqueous solution with stirring slowly to prepare an emulsified system.

[0310] Next, the pH was lowered to 4.0 using an aqueous acetic acid solution under predetermined stirring conditions to form a gelatin / gum arabic coagulated layer, and then cooled to about 5° C. in about 30 minutes.

[0311] Then 10 g of formaldehyde 35% aqueous solution was added, the temperature was raised to 50° C., and a curing reaction was carried out for about 2 hours to prepare...

Embodiment 2

[0317] (1) Preparation of liquid for electrophoresis display

[0318] 100 g of the dispersion was prepared according to the mixing ratio described in Example 9 above.

[0319] (2) Microencapsulation

[0320] After dissolving 10 g of hexamethylene diisocyanate (HDI) in the above dispersion (1), immediately add 300 g of 5% by weight gelatin aqueous solution under specified stirring conditions to prepare an emulsified system, maintain the temperature at 35 ° C, and continue After stirring for 2 hours, the temperature of the system was cooled to 5°C.

[0321] Next, after adjusting the pH to 9.0 with sodium hydroxide, 10 g of a 25% aqueous solution of glutaraldehyde was added, the temperature of the system was raised to 50° C., and the encapsulation reaction was completed in about 2 hours.

[0322] The average particle diameter of the obtained microcapsules was 90 μm.

[0323] (3) Device evaluation

[0324] 1 part of the microcapsule slurry obtained in (2) above was mixed with ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
particle sizeaaaaaaaaaa
particle sizeaaaaaaaaaa
particle sizeaaaaaaaaaa
Login to View More

Abstract

Examples of the medium for electrophoretic display using a liquid for electrophoretic display that can reversibly change the visible state by the action of an electric field, etc., include substances obtained by encapsulating the liquid for electrophoretic display in microcapsules or small cells, each of which is an independent structure. , wherein the liquid for electrophoretic display contains at least an alkyl polyether amine having a structural unit represented by a specific structural formula, one or more particles, a dispersant and a dispersion medium, and the particles contain particles treated with lipophilic surface . In addition, examples of the electrophoretic display device include a pair of substrates and the electrophoretic display medium interposed between the substrates, and at least one of the pair of substrates is formed with a light-transmitting electrode. The electrophoretic display medium using the liquid for electrophoretic display and the display surface of the electrophoretic display device have a high contrast ratio, can perform contrast display with high reliability even in repeated display, and are also excellent in responsiveness.

Description

technical field [0001] The present invention relates to a display liquid for electrophoretic display capable of reversibly changing a visible state by the action of an electric field or the like, a display medium and a display device using the liquid for electrophoretic display. Background technique [0002] In recent years, along with the development of information equipment, there has been an increasing demand for low power consumption, thinning, and flexibility of display devices, and research and development of display devices that meet these needs have been flourishing. [0003] As one of such display devices, there is known an electrophoretic display device invented by Harold D. Lees et al. This electrophoretic display device has a structure in which two electrode substrates, at least one of which is transparent, are arranged facing each other through a suitable spacer, and a display liquid is filled between the electrode substrates to form a display panel. The display...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): G02F1/167
Inventor 荻原康明佐藤厚志长田隆博小山隆雄
Owner MITSUBISHI PENCIL CO LTD