Display device

Patent metadata

Field	Value
Publication number	US-9983439-B2
Application number	US-201615185959-A
Country	US
Kind code	B2
Filing date	Jun 17, 2016
Priority date	Jul 2, 2015
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

According to one embodiment, a wavelength converter includes a microlens which condenses excitation light, a reflective layer which is opposed to the microlens and includes an aperture, and a wavelength conversion element which is opposed to the microlens via the reflective layer, absorbs the excitation light, and emits emission light whose wavelength is different from that of the excitation light.

First claim

What is claimed is:

1. A wavelength converter comprising:
a microlens which condenses excitation light;
a reflective layer which is opposed to the microlens and includes an aperture; and
a wavelength conversion element which is opposed to the microlens via the reflective layer, absorbs the excitation light, and emits emission light whose wavelength is different from that of the excitation light,
wherein the wavelength conversion element has optical absorption anisotropy.

2. The wavelength converter of claim 1 , wherein the wavelength conversion element comprises a quantum dot which absorbs the excitation light and emits the emission light.

3. The wavelength converter of claim 1 , wherein:
the aperture extends in one direction; and
the microlens is a cylindrical lens which condenses the excitation light linearly parallel to the direction in which the aperture extends.

4. The wavelength converter of claim 3 , wherein the direction in which the aperture extends is parallel to a direction of polarization of the excitation light.

5. The wavelength converter of claim 4 , wherein an absorption axis direction of the wavelength conversion element is parallel to the direction in which the aperture extends.

6. The wavelength converter of claim 2 , wherein the quantum dot is shaped like a rod having a long axis.

7. The wavelength converter of claim 6 , wherein the quantum dot has a polar axis which agrees with the long axis.

8. The wavelength converter of claim 1 , further comprising a buffer layer which adjusts a focal distance of the microlens between the microlens and the reflective layer.

9. The wavelength converter of claim 1 , further comprising a dielectric multilayer film which is opposed to the reflective layer via the wavelength conversion element, and whose reflectivity against the excitation light is higher than that against the emission light.

10. The wavelength converter of claim 9 , wherein the reflectivity of the dielectric multilayer film against S-polarized excitation light becomes 90% or more at all angles of incidence.

11. The wavelength converter of claim 9 , wherein the reflective layer has a lower reflectivity against the excitation light and a higher reflectivity against the emission light as compared to the reflectivities exhibited by the dielectric multilayer film.

12. The wavelength converter of claim 1 , wherein the excitation light is blue light or ultraviolet light.

13. A display device comprising:
a display panel comprising a first substrate, a second substrate arranged to be opposed to the first substrate, and a liquid crystal layer held between the first substrate and the second substrate;
a light source which is disposed on a side opposed to the first substrate of the display panel, and emits excitation light toward the display panel;
a first polarizer arranged between the first substrate and the light source;
a second polarizer opposed to the first polarizer via the display panel; and
a wavelength converter comprising microlenses which condense the excitation light, a reflective layer which is opposed to the microlenses and includes apertures, and a first wavelength conversion element and a second wavelength conversion element which are opposed to the microlenses via the reflective layer, absorb the excitation light, and emit first emission light and second emission light whose wavelengths are different from the wavelength of the excitation light, respectively,
wherein directions of polarization of the first and second emission light are parallel to a direction of polarization of the excitation light when the excitation light is absorbed by the first and second wavelength conversion elements.

14. The display device of claim 13 , wherein:
the first wavelength conversion element comprises a first quantum dot which absorbs the excitation light and emits the first emission light;
the second wavelength conversion element comprises a second quantum dot which absorbs the excitation light and emits the second emission light;
the excitation light is blue light;
the first emission light is green light; and
the second emission light is red light.

15. The display device of claim 13 , wherein:
the first wavelength conversion element comprises a first quantum dot which is shaped like a rod and has a first long axis;
the second wavelength conversion element comprises a second quantum dot which is shaped like a rod and has a second long axis whose size is different from that of the first long axis;
the first quantum dot has a first absorption axis parallel to the first long axis;
the second quantum dot has a second absorption axis parallel to the second long axis; and
the first and second long axes are parallel to the first and second absorption axes, respectively, and are parallel to a transparent axis direction of the first polarizer.

16. The display device of claim 13 , wherein:
the apertures extend in a direction parallel to a transparent axis direction of the first polarizer; and
each of the microlenses is a cylindrical lens which has a generatrix parallel to the transparent axis direction, and linearly condenses the excitation light parallel to a direction in which the apertures extend.

17. The display device of claim 13 , further comprising a dielectric multilayer film which is opposed to the reflective layer via the wavelength conversion elements, and whose reflectivity against the excitation light is higher than those against the first and second emission light.

18. The display device of claim 13 , wherein the wavelength converter is arranged between the light source and the first polarizer within the display panel, or at a position opposed to the display panel via the second polarizer.

Assignees

• Japan Display Inc

Inventors

• Mizunuma Tatsuro
• Araki Shigesumi
• Miki Hirohisa

Classifications

• G02F1/133528

  Polarisers · CPC title

• G02F2001/136222

  Physics · mapped topic

• G02F1/134363

  for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS] · CPC title

• G02F1/133526 Primary

  Lenses, e.g. microlenses or Fresnel lenses · CPC title

• G02F2202/36

  Micro- or nanomaterials · CPC title