Wavelength conversion device and illumination device
A wavelength conversion device includes a flat plate-shaped phosphor portion, a first nanoantenna group, a translucent body portion, and a second nanoantenna group. The flat plate-shaped phosphor portion includes a phosphor to be excited by an excitation light to emit a fluorescence. The first nanoantenna group is provided at a lower surface side of the phosphor portion and includes a plurality of first metal nanoantennas arranged at a first pitch. The translucent body portion is filled between adjacent first nanoantennas, formed on the lower surface of the phosphor portion to cover the lower surface of the phosphor portion, and made of a translucent material. The second nanoantenna group is provided on an upper surface of the phosphor portion and includes a plurality of second metal nanoantennas arranged at a second pitch on the upper surface of the phosphor portion.
1 . An illumination device comprising:
a light source that emits excitation light;
a plurality of first nanoantennas provided above the light source, the respective plurality of first nanoantennas being provided at a first pitch and being made of metals;
a translucent body portion that is filled between the adjacent first nanoantennas, the translucent body portion being made of a translucent material without a phosphor;
a flat plate-shaped phosphor portion provided on the translucent body portion, the phosphor portion including a phosphor excitable by the excitation light to emit a fluorescence, and the translucent body portion being formed on a lower surface of the phosphor portion to cover the lower surface of the phosphor portion; and
a plurality of second nanoantennas provided on an upper surface of the phosphor portion, the respective plurality of second nanoantennas being provided on the upper surface of the phosphor portion at a second pitch and being made of metals.
2 . The illumination device according to claim 1 , wherein the translucent body portion has translucency to fluorescence having a wavelength in range of at least 480 nm to 700 nm.
3 . The illumination device according to claim 1 , wherein the translucent body portion has translucency to the excitation light.
4 . The illumination device according to claim 1 , wherein the translucent body portion is made of SiO2 film.
5 . A wavelength conversion device comprising:
a first translucent portion;
a second translucent portion provided on the first translucent portion and including a plurality of first nanoantennas and a translucent body portion, the respective plurality of first nanoantennas being provided on the first translucent portion at a first pitch and being made of metals, and the translucent body portion being formed on the first translucent portion, filled between the adjacent first nanoantennas, and made of a translucent material;
a flat plate-shaped phosphor portion provided on the second translucent portion and including a phosphor to be excited by an excitation light to emit a fluorescence; and
a plurality of second nanoantennas provided on an upper surface of the phosphor portion, the respective plurality of second nanoantennas being provided on the upper surface of the phosphor portion at a second pitch and being made of metals,
wherein the translucent body portion covers a lower surface of the phosphor portion.
6 . The wavelength conversion device according to claim 5 , wherein the first pitch is equal to or less than the second pitch.
7 . The wavelength conversion device according to claim 5 , wherein the first nanoantennas have a cone shape or a truncated cone shape narrowing upward.
8 . The wavelength conversion device according to claim 5 , wherein the second nanoantennas have a cone shape or a truncated cone shape narrowing upward.
9 . The wavelength conversion device according to claim 5 , wherein the first nanoantennas are formed only in one area of the upper surface of the translucent portion.
10 . The wavelength conversion device according to claim 5 , further comprising:
a light reflecting member formed at a part of a side surface of the wavelength conversion device and continuously formed from a lower end of a side surface of the translucent body portion to an upper end of a side surface of the phosphor portion.
11 . The wavelength conversion device according to claim 5 , wherein:
the phosphor portion has a property of being excited by the excitation light to emit the fluorescence having a peak wavelength of 520 nm to 570 nm, and
the first nanoantennas have the first pitch of 500 nm or less.
12 . The wavelength conversion device according to claim 11 , wherein the phosphor portion is made of yttrium aluminum garnet activated with cerium.
13 . The wavelength conversion device according to claim 5 , wherein the phosphor portion includes a single crystal phosphor.
14 . The wavelength conversion device according to claim 5 , wherein the first nanoantennas and the second nanoantennas are arranged in a square grid pattern or a triangular grid pattern.
15 . The wavelength conversion device according to claim 5 , wherein the first nanoantennas and the second nanoantennas are made of Al or Ag.
16 . An illumination device comprising:
the wavelength conversion device according to claim 1 ; and
a light source that emits the excitation light toward the phosphor portion.