Display element and display apparatus
A display element includes a sub-pixel region including a wavelength conversion layer that converts a wavelength of excitation light, and further includes a low refractive index layer provided in a region between a wavelength conversion portion and an optical member.
1 . A display element comprising:
a light source portion that emits excitation light;
a wavelength conversion portion that converts the excitation light to light with a wavelength longer than a wavelength of the excitation light;
an excitation light reflective layer that reflects the excitation light having penetrated through the wavelength conversion portion; and
an optical member that transmits light converted by the wavelength conversion portion, in this order, wherein
the wavelength conversion portion includes a first wavelength conversion layer that converts the excitation light to first wavelength converted light with a wavelength longer than the wavelength of the excitation light, and a second wavelength conversion layer that converts the excitation light to second wavelength converted light with a wavelength longer than the wavelength of the first wavelength converted light,
the display element is a component of a pixel that includes a green sub-pixel region including the first wavelength conversion layer, a red sub-pixel region including the second wavelength conversion layer, and a blue sub-pixel region not including the first wavelength conversion layer or the second wavelength conversion layer,
the display element further comprises a low refractive index layer provided in a region between the wavelength conversion portion and the optical member,
a surface of the low refractive index layer adjacent to the wavelength conversion portion is an interface at which the low refractive index layer is in contact with a region having a higher refractive index than the low refractive index layer,
the excitation light is blue light,
the blue sub-pixel region has a resin portion containing light scattering particles that scatter the blue light, and
an all-angle mean transmittance of the excitation light reflective layer for the blue light is lower than or equal to 32%.
2 . The display element according to claim 1 , wherein the excitation light reflective layer is a dielectric multilayer film.
3 . The display element according to claim 2 , wherein the dielectric multilayer film includes a laminated body in which a layer containing TiO 2 and a layer containing SiO 2 are alternately laminated.
4 . The display element according to claim 1 , wherein the all-angle mean transmittance of the excitation light reflective layer for the blue light is lower than or equal to 20%.
5 . The display element according to claim 1 , wherein
the excitation light reflective layer is provided one by one for each of the red sub-pixel region and the green sub-pixel region, and
an all-angle mean transmittance of the excitation light reflective layer for the blue light, provided for the red sub-pixel region, is lower than or equal to 15%.
6 . The display element according to claim 1 , wherein
the excitation light reflective layer is provided one by one for each of the red sub-pixel region and the green sub-pixel region, and
an all-angle mean transmittance of the excitation light reflective layer for the blue light, provided for the red sub-pixel region, is lower than or equal to 7%.
7 . The display element according to claim 1 , wherein the refractive index of the low refractive index layer is higher than or equal to 1.10 and lower than or equal to 1.30.
8 . The display element
according to claim 1 , wherein the refractive index of the low refractive index layer is higher than or equal to 1.10 and lower than or equal to 1.15.
9 . The display element according to claim 1 , wherein a thickness of the low refractive index layer is greater than or equal to 200 nm.
10 . The display element according to claim 1 , wherein a thickness of the low refractive index layer is less than or equal to one-half a thickness of the wavelength conversion portion.
11 . The display element according to claim 1 , wherein a thickness of the low refractive index layer is less than or equal to 2 μm.
12 . The display element according to claim 1 , wherein the low refractive index layer contains fumed silica particles.
13 . The display element according to claim 1 , wherein a voidage of the low refractive index layer is higher than or equal to 60.0% and lower than or equal to 95.0%.
14 . The display element according to claim 1 , wherein the low refractive index layer is formed by an inkjet method.
15 . The display element according to claim 1 , wherein the first wavelength conversion layer and the second wavelength conversion layer contain quantum dots.
16 . The display element according to claim 1 , wherein a thickness of each of the first wavelength conversion layer and the second wavelength conversion layer is greater than or equal to 6 μm and less than or equal to 10 μm.
17 . The display element according to claim 1 , further comprising
a partition wall provided between any adjacent two of the green sub-pixel region, the red sub-pixel region, and the blue sub-pixel region, wherein
a surface of the low refractive index layer adjacent to the wavelength conversion portion is located closer to the wavelength conversion portion than to a top surface of the partition wall adjacent to the optical member.
18 . The display element according to claim 1 , wherein the optical member includes a microlens.
19 . The display element according to claim 1 , wherein
the excitation light is ultraviolet light,
the wavelength conversion portion includes a third wavelength conversion layer that converts the excitation light to third wavelength converted light with a wavelength longer than the wavelength of the excitation light and shorter than the wavelength of the first wavelength converted light, and
the blue sub-pixel region includes the third wavelength conversion layer.