Display device, image display device and display method

1. A display device, comprising:

a display portion which has a cavity portion surrounded by wall surfaces, at least one part of said wall surfaces being formed of a transparent member and forming a structural color forming surface provided with fine asperities having predetermined regularity;

a liquid which is hermetically sealed so as to have a liquid surface in said cavity portion, and has a refractive index approximately equivalent to a refractive index of said transparent member;

an actuator which gives a disturbance to said liquid to bring said liquid into contact with said structural color forming surface; and

a control unit which controls driving of said actuator to switch reflection and transmission characteristics of light when the light is incident into said structural color forming surface, thereby controlling color display using reflected light formed by said structural color forming surface.

2. The display device according to claim 1 , wherein

said actuator comprises a heater element which heats said liquid; and

said heater element generates Marangoni convection by heating said liquid and allows said liquid to be ejected onto said structural color forming surface.

3. The display device according to claim 1 , wherein said structural color forming surface is provided with said fine asperities having a predetermined cycle.

4. The display device according to claim 1 , wherein said display portion includes a wall surface into which said light having transmitted through said structural color forming surface is incident, and said wall surface is formed of a transparent member such that said light having transmitted through said structural color forming surface transmits through said wall surface.

5. The display device according to claim 1 , wherein said display portion includes a black layer onto which said light having transmitted through said structural color forming surface is incident.

6. The display device according to claim 1 , wherein said liquid is transparent and colorless.

7. The display device according to claim 1 , wherein

said display device is constructed of a multilayer structure in which plural units are stacked on one another, each unit being assembled from said display portion, said liquid and said actuator in a layer,

said display portion in each unit includes a wall surface into which said light having transmitted through said structural color forming surface is incident, said wall surface is formed of a transparent member such that said light having transmitted through said structural color forming surface transmits through said wall surface, and

said fine asperities with which said structural color forming surfaces of said display portions are provided are different from one another in regularity.

8. The display device according to claim 1 , wherein

said display device is constructed of a multilayer structure in which plural units are stacked on one another, each unit being assembled from said display portion, said liquid, and said actuator in a layer,

said fine asperities with which said structural color forming surfaces of said display portions in respective units include are different from one another in regularity,

said display portions in remaining layers excluding a lowermost layer among said respective layers include wall surfaces into which said light having transmitted through said structural color forming surface is incident, said wall surfaces are formed of transparent members such that said light having transmitted through said structural color forming surface transmits through said wall surfaces, and said display portion in said lowermost layer includes a black wall surface onto which said light having transmitted through said structural color forming surface is incident.

9. An image display device, comprising:

a segment matrix in which plural segments are arrayed in matrix, each segment being constructed by arraying plural display devices; and

a driving circuit which is connected to said arrayed plural display devices and drives at least one of said arrayed plural display devices to allow an image to be formed on said segment matrix,

wherein each of said arrayed plural display devices comprises:

a display portion which has a cavity portion surrounded by wall surfaces, at least one part of said wall surfaces being formed of a transparent member and forming a structural color forming surface provided with fine asperities having predetermined regularity;

a liquid which is hermetically sealed so as to have a liquid surface in said cavity portion, and has a refractive index approximately equivalent to a refractive index of said transparent member;

an actuator which gives a disturbance to said liquid to bring said liquid into contact with said structural color forming surface; and

a control unit which controls driving of said actuator to switch reflection and transmission characteristics of light when the light is incident into said structural color forming surface, thereby controlling color display using reflected light formed by said structural color forming surface.

10. An image display device, comprising:

a segment matrix in which plural display devices are arrayed in matrix; and

a driving circuit which is connected to said plural display devices arrayed in the matrix and drives at least one of said plural display devices arrayed in the matrix to allow an image to be formed on said segment matrix,

wherein each of said plural display devices arrayed in the matrix comprises:

a display portion which has a cavity portion surrounded by wall surfaces, at least one part of said wall surfaces being formed of a transparent member and forming a structural color forming surface provided with fine asperities having predetermined regularity;

a liquid which is hermetically sealed so as to have a liquid surface in said cavity portion, and has a refractive index approximately equivalent to a refractive index of said transparent member;

an actuator which gives a disturbance to said liquid to bring said liquid into contact with said structural color forming surface; and

a control unit which controls driving of said actuator to switch reflection and transmission characteristics of light when the light is incident into said structural color forming surface, thereby controlling color display using reflected light formed by said structural color forming surface.

11. The display device according to claim 10 , wherein

said display device is constructed of a multilayer structure in which plural units are stacked on one another, each unit being assembled from said display portion, said liquid and said actuator in a layer,

said display portion in each unit includes a wall surface into which said light having transmitted through said structural color forming surface is incident, said wall surface is formed of a transparent member such that said light having transmitted through said structural color forming surface transmits through said wall surface, and

said fine asperities with which said structural color forming surfaces of said display portions are provided are different from one another in regularity.

12. The display device according to claim 10 , wherein

said display device is constructed of a multilayer structure in which plural units are stacked on one another, each unit being assembled from said display portion, said liquid, and said actuator in a layer,

said fine asperities with which said structural color forming surfaces of said display portions in respective units include are different from one another in regularity,

said display portions in remaining layers excluding a lowermost layer among said respective layers include wall surfaces into which said light having transmitted through said structural color forming surface is incident, said wall surfaces are formed of transparent members such that said light having transmitted through said structural color forming surface transmits through said wall surfaces, and said display portion in said lowermost layer includes a black wall surface onto which said light having transmitted through said structural color forming surface is incident.

13. A display method, comprising:

previously forming a structural color forming surface in which at least one part of wall surfaces of a cavity portion is formed of a transparent member and which is provided with fine asperities having predetermined regularity on said at least one part; and

controlling reflection and transmission characteristics of light on said structural color forming surface to exhibit a predetermined structural color by bringing, into contact with said structural color forming surface, a liquid having a refractive index approximately equivalent to a refractive index of said transparent member when said light is incident into said structural color forming surface, thereby controlling color display.