Dispersion liquid for electrophoretic display, display medium, and display device

• US 9,348,193 B2
• Filed: 12/18/2012
• Issued: 05/24/2016
• Est. Priority Date: 02/27/2012
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink Holdings Incorporated
• Inventors: Jun, Cao, Hiji, Naoki, Mizutani, Ryota, Manabe, Chikara, Aoshima, Toshihide, Nakayama, Daisuke, Yamamoto, Yasuo
• Primary Examiner(s): Choi, Ling
• Assistant Examiner(s): Nguyen, Thuy-Ai
• Application Number:
  US13/718,741
• Publication Number:
  US 20130222885A1
• Time in Patent Office: 1,253 Days
• Field of Search: 252/581
• US Class Current: 1/1
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 2001/1678 characterised by the composition or particle type

Abstract

There is provided a dispersion liquid for electrophoretic display, containing a dispersion medium 50, a colored electrophoretic particle group 34 that is dispersed in the dispersion medium and migrates in the dispersion medium according to an electric field, a non-electrophoretic particle group 36 that is dispersed without migrating in the dispersion medium and has a color different from that of the electrophoretic particle group, and a compound having a neutral polar group and a hydrophobic group, which is contained in the dispersion medium in a ratio of about 0.01 to about 1 mass % based on the entire dispersion liquid.

Claims

1. A dispersion liquid for electrophoretic display, comprising:

a dispersion medium,

a colored electrophoretic particle group that is dispersed in the dispersion medium and migrates in the dispersion medium according to an electric field,

a non-electrophoretic particle group that is dispersed without migrating in the dispersion medium and has a color different from that of the electrophoretic particle group, and

a compound having a neutral polar group and a hydrophobic group, which is contained in the dispersion medium in a ratio of about 0.01 to about 1 mass % based on the entire dispersion liquid.

2. The dispersion liquid for electrophoretic display according to claim 1,

wherein the neutral polar group is a hydroxyl group, an alkyl ether group, a weak acid group neutralized with a weak base, or a weakly basic group neutralized with a weak acid group.

3. The dispersion liquid for electrophoretic display according to claim 1,

wherein a silicone-based oil is contained as the dispersion medium and the compound having a neutral polar group and a hydrophobic group has a siloxane bond-containing group as the hydrophobic group.

4. The dispersion liquid for electrophoretic display according to claim 1,

wherein a hydrocarbon-based oil is contained as the dispersion medium and the compound having a neutral polar group and a hydrophobic group has an alkyl group as the hydrophobic group.

5. A display medium comprising:

a pair of substrates disposed with spacing, at least either one of which has light transparency, and

the dispersion liquid for electrophoretic display according to claim 1, which is enclosed between the pair of substrates.

6. A display medium comprising:

a pair of electrodes disposed with spacing, at least either one of which has light transparency, and

a region having the dispersion liquid for electrophoretic display according to claim 1 between the pair of electrodes.

7. A display device comprising:

the display medium according to claim 5, and

an electric field applying unit that applies a voltage between the pair of substrates of electrodes of the display medium.

8. A display device comprising:

the display medium according to claim 6, and

an electric field applying unit that applies a voltage between the pair of electrodes of the display medium.