Display body and observing method for display body
A display body includes a first display part, which displays first information, and a second display part, which displays second information of a larger display size than the first information. The second display part includes the entire first display part as a part of the second display part. The first display part has a plasmon structure. The plasmon structure includes an interface between a metal layer and a dielectric layer, which transmits light, and is configured so that surface plasmons are excited in the interface to change irradiation light with which the interface is irradiated to transmitted light having a color different from that of the irradiation light. The first information is displayed with the transmitted light.
1. A display body comprising:
a first display part, which displays first information; and
a second display part, which displays second information having a display size greater than that of the first information, wherein
the second display part includes the entire first display part as a part of the second display part,
the first display part includes a plasmon structure, and
the plasmon structure is configured to
include an interface between a metal layer and a dielectric layer that transmits light,
excite surface plasmons in the interface to change irradiation light with which the interface is irradiated to transmitted light having a color different from that of the irradiation light, and
display the first information with the transmitted light,
the dielectric layer includes a base surface and a plurality of protrusions protruding from the base surface,
the base surface and an imaginary plane including top surfaces of a plurality of the protrusions are substantially parallel to each other,
the metal layer covers at least a part of the dielectric layer,
in the metal layer, a part located on one of the top surfaces includes a flat portion extending along the top surface and a peripheral surface having a curved shape, which is provided in a periphery of the flat portion and protrudes toward an outside of the flat portion, and
in the metal layer, a part located on the base surface has a convex shape, which protrudes to the largest degree at a substantially center of a region between the protrusions adjacent to each other.
2. The display body according to claim 1 , wherein
the first information includes a plurality of information elements,
the plurality of information elements include a first information element, which represents a first color, and a second information element, which represents a second color,
the first display part includes a plurality of display elements, and
each display element corresponds to one of the information elements.
3. The display body according to claim 2 , wherein at least one of the display elements includes a plurality of the plasmon structures, which change the irradiation light to the transmitted light having different colors.
4. The display body according to claim 1 , wherein, in the dielectric layer, a distance between the base surface and the imaginary plane is 30 nm or more and 500 nm or less.
5. The display body according to claim 1 , wherein
a thickness of the metal layer is 20 nm or more and 100 nm or less, and
in a material for forming the metal layer, a real part of a complex dielectric constant in a visible light range has a negative value.
6. The display body according to claim 1 , wherein
each of the protrusions has a side surface connecting the top surface and the base surface, and
the metal layer covers the base surface and the top surface of each of the protrusions and covers at least a part of the side surface.
7. The display body according to claim 6 , wherein, in the metal layer, a thickness of a part covering the side surface is less than a thickness of a part covering the top surface and a thickness of a part covering the base surface.
8. The display body according to claim 1 , wherein
the plurality of protrusions are arranged in the base surface in a state of one of a trigonal lattice shape, a tetragonal lattice shape, and a hexagonal lattice shape, and
as viewed from a plane facing the base surface, a distance between centers of the protrusions in the protrusions adjacent to each other is 100 nm or more and 600 nm or less.
9. The display body according to claim 1 , wherein the plurality of protrusions is arranged irregularly on the base surface.
10. The display body according to claim 1 , wherein
the first display part includes a plurality of display elements,
each of the plurality of display elements is configured with a part of the dielectric layer including at least one of the protrusions, and
in at least a part of the plurality of display elements, at least one of an inter-center distance between the protrusions as viewed from a plane facing the base surface, a distance between the base surface and the imaginary plane, an arrangement state of the protrusions, a thickness of the metal layer, and a material for forming the metal layer differs among the display elements.
11. The display body according to claim 10 , wherein
each of the display elements defines a polygonal shaped region, and
a length of one side of the polygonal shaped region is 200 nm or more and 3000 nm or less.
12. The display body according to claim 10 , wherein
the plurality of display elements are arranged in a matrix shape, and
the number of display elements arranged in each of a row direction and a column direction perpendicular to the row direction is 10 or more and 100 or less.
13. A method for observing a display body, wherein
the display body includes:
a first display part, which displays first information; and
a second display part, which displays second information having a display size greater than that of the first information,
the second display part includes the entire first display part as a part of the second display part,
the first display part includes a plasmon structure, and
the plasmon structure is configured to
include an interface between a metal layer and a dielectric layer that transmits light,
excite surface plasmons in the interface to change irradiation light with which the interface is irradiated to transmitted light having a color different from that of the irradiation light, and
display the first information with the transmitted light,
the dielectric layer includes a base surface and a plurality of protrusions protruding from the base surface,
the base surface and an imaginary plane including top surfaces of a plurality of the protrusions are substantially parallel to each other,
the metal layer covers at least a part of the dielectric layer,
in the metal layer, a part located on one of the top surfaces includes a flat portion extending along the top surface and a peripheral surface having a curved shape, which is provided in a periphery of the flat portion and protrudes toward an outside of the flat portion, and
in the metal layer, a part located on the base surface has a convex shape, which protrudes to the largest degree at a substantially center of a region between the protrusions adjacent to each other,
the method comprising:
irradiating the interface of the display body with the irradiation light; and
observing the display body irradiated with the irradiation light under a microscope.