Display device

• US 10,295,882 B2
• Filed: 07/12/2017
• Issued: 05/21/2019
• Est. Priority Date: 03/11/2010
• Status: Active Grant

• Current Assignee: National University Corporation Chiba University
• Original Assignee: National University Corporation Chiba University
• Inventors: Kobayashi, Norihisa, Nakamura, Kazuki, Watanabe, Yuichi
• Primary Examiner(s): Gyllstrom, Bryon T
• Application Number:
  US15/647,732
• Publication Number:
  US 20170371219A1
• Time in Patent Office: 678 Days
• Field of Search: 362326, 362260, 362330
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/182 of the rare earth metals, i.e. Sc, Y or lanthanide
• CPC Class Codes: F21V 9/00 Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters coloured shades F21V1/00; elements characterised by cooling arrangements F21V29/502
• CPC Class Codes: G02F 1/1503 caused by oxidation-reduction reactions in organic liquid solutions, e.g. viologen solutions
• CPC Class Codes: G02F 1/157 Structural association of cells with optical devices, e.g. reflectors or illuminating devices
• CPC Class Codes: G02F 2202/046 fluorescent
• CPC Class Codes: G09F 9/30 in which the desired character or characters are formed by combining individual elements panels comprising a number of electrodes in a single cell controlling light arriving from an independent light source, e.g. electro-optical or magneto-optical cell, G02F1/00
• CPC Class Codes: G09F 9/3023 Segmented electronic displays
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field

Abstract

Disclosed is a high quality display device which avoids complicated element structure, and does not unnecessarily reduce portability. The display device comprises: a pair of substrates which are disposed facing each other, and on each of which electrodes are formed; and a material layer which is sandwiched between the pair of substrates. The material layer contains: a coloring material which changes color upon the application of a voltage; and a light-emitting material which emits light upon photoexcitation.

Claims

1. A display device, comprising:

a pair of substrates which are disposed facing each other, and on each of which electrodes are formed; and

a material layer which is sandwiched between the pair of substrates;

wherein the material layer contains a coloring material which changes color upon the application of a DC voltage, and a light-emitting material which emits light upon excitation based on an AC voltage,

wherein when applying the DC voltage, the coloring material changes color through an oxidation-reduction reaction, whereas the light-emitting material does not emit light,

wherein the light-emitting material contains at least one of Ru(bpy)₃(PF₆)₂, RuPF₆, RuCl₆, PVB (polyvinyl butyral), and TBAP (tetrabutylammonium perchlorate),

wherein when applying the AC voltage, the light-emitting material emits light, whereas the coloring material is not actually colored.

2. The display device according to claim 1, wherein the strength of the DC voltage is in a range of 1.0×

10⁴ V/m to 1.0×

10⁶ V/m.

3. The display device according to claim 1, wherein a strength of the AC voltage is in a range of 1.0×

10⁴ V/m to 1.0×

10⁶ V/m, and a frequency of the AC voltage is in a range of 10 Hz to 1000 Hz.

4. The display device according to claim 1, wherein the coloring material includes at least any of 1,4-diacetyl benzene, N,N′

-dimethyl viologen, poly(3,4-ethylenedioxythiophene), polyaniline, 1,4-diheptyl viologen, 4,4′

-biphenyl dicarboxylic acid diethyl ester, and dimethyl terephthalate.

5. The display device according to claim 1, wherein one of the electrodes is modified by the coloring material.

6. The display device according to claim 1, wherein one of the electrodes is modified by the light-emitting material.

7. The display device according to the claim 1, wherein at least one of the coloring material and the light-emitting material is dispersed to the concentration of 5 mM or more and 300 mM or less in the material layer.

8. The display device according to claim 1, wherein an energy difference between a ground state and an excited state of the coloring material is less than 1800 cm⁻

1 from that of the light-emitting material.

9. The display device according to claim 1, wherein the coloring material is adjacent to the light-emitting material.

10. The display device according to claim 1, wherein when applying the AC voltage, the light-emitting material emits light in areas where the voltage between the pair of electrodes is removed, and the light-emitting material does not emit light in areas where the voltage between the pair of electrodes is applied.

11. The display device according to claim 1, further comprising a light source for photoexcitation.

12. A display device, comprising:

a pair of substrates which are disposed facing each other, and on each of which electrodes are formed;

a material layer which is sandwiched between the pair of substrates;

wherein the material layer contains a coloring material which changes color upon the application of a DC voltage, and a light-emitting material which emits light upon excitation based on an AC voltage,

wherein when applying the DC voltage, the coloring material is colored by an oxidation-reduction reaction,

wherein the light-emitting material contains Ru complex,

the coloring materials contains at least one of DMT 1,4-diacetyl benzene, 4,4-biphenyl dicarboxylic acid diethyl ester,

wherein when applying the AC voltage, the light-emitting material emits light, whereas the coloring material is not actually colored.

13. A display device, comprising:

a pair of substrates which are disposed facing each other, and on each of which electrodes are formed; and

a material layer which is sandwiched between the pair of substrates;

wherein the material layer contains a coloring material which changes color upon the application of a DC voltage but not an AC voltage, and a light-emitting material which emits light upon excitation based on an AC voltage but does not emit light upon application of a DC voltage,

wherein when applying the DC voltage, the coloring material changes color through an oxidation-reduction reaction, whereas the light-emitting material does not emit light,

wherein the light-emitting material contains at least one of Ru(bpy)₃(PF₆)₂, RuPF₆, RuCl₆, PVB (polyvinyl butyral), and TBAP (tetrabutylammonium perchlorate).