Beam expanding film and holographic display apparatus including the same

Patent metadata

Field	Value
Publication number	US-12124216-B2
Application number	US-202117371415-A
Country	US
Kind code	B2
Filing date	Jul 9, 2021
Priority date	Feb 8, 2021
Publication date	Oct 22, 2024
Grant date	Oct 22, 2024

Abstract

A beam expanding film includes a first material layer and a photonic crystal layer that expands a width of incident light and emits light having an expanded width. The photonic crystal layer includes a first material layer and a plurality of second material layers buried in the first material layer. A holographic display apparatus includes a backlight unit configured to provide coherent collimated light; a beam expanding film described above and facing the backlight unit; a flat panel arranged between the backlight unit and the beam expanding film to provide a hologram; and a lens configured to focus a holographic image on a space.

First claim

What is claimed is:

1. A beam expanding film comprising:
a photonic crystal layer that expands a width of incident light and emits light having an expanded width, the photonic crystal layer comprising:
a first material layer; and
a plurality of second material layers buried in the first material layer,

wherein each of the plurality of second material layers comprises a plurality of stacked first layers and second layers.

2. The beam expanding film of claim 1 , further comprising a transparent substrate having a refractive index less than a refractive index of the photonic crystal layer,
wherein the photonic crystal layer is provided on the transparent substrate.

3. The beam expanding film of claim 1 ,
wherein each of the plurality of second material layers is separated from and parallel to each other, and
wherein each of the plurality of second material layers has a rod shape having a round cross-section.

4. The beam expanding film of claim 1 , wherein a space between adjacent second material layers of the plurality of second material layers is filled with the first material layer.

5. The beam expanding film of claim 1 , wherein each of the plurality of second material layers comprises amorphous silicon.

6. The beam expanding film of claim 1 , wherein each of the plurality of second material layers is separated from and parallel to each other of the plurality of second material layers, and
wherein each of the plurality of second material layers comprises a plane facing a plane of each other of the plurality of second material layers.

7. The beam expanding film of claim 1 , wherein each of the plurality of second material layers is arranged perpendicular to the incident light.

8. The beam expanding film of claim 1 , wherein the plurality of stacked first layers and second layers are sequentially and alternately stacked.

9. The beam expanding film of claim 1 , wherein a refractive index of the first material layer, a refractive index of the plurality of first layers, and a refractive index of the plurality of second layers are different from each other.

10. The beam expanding film of claim 9 , wherein the refractive index of the first material layer is less than the refractive index of the plurality of second layers, and the refractive index of the plurality of first layers is greater than the refractive index of the plurality of second layers.

11. The beam expanding film of claim 1 , wherein, when a wavelength of the incident light is λ, a thickness of each of the plurality of stacked first layers and second layers is about λ/4.

12. The beam expanding film of claim 1 , wherein each of the plurality of first layers comprises a material that is transparent to the incident light and has a refractive index greater than a refractive index of the plurality of second layers.

13. The beam expanding film of claim 1 , wherein each of the plurality of second layers comprises a material that is transparent to the incident light and has a refractive index less than a refractive index of the plurality of first layers.

14. A beam expanding film comprising:
a photonic crystal layer that expands a width of incident light and emits light having an expanded width, the photonic crystal layer comprising:
a first material layer; and
a plurality of second material layers buried in the first material layer,

wherein the photonic crystal layer comprises a double-zero index (DZI) material.

15. A holographic display apparatus comprising:
a backlight unit configured to provide coherent collimated light;
a beam expanding film facing the backlight unit, the beam expanding film comprising a photonic crystal layer that expands a width of incident light and emits light having an expanded width, the photonic crystal layer comprising a first material layer and a plurality of second material layers buried in the first material layer;
a flat panel arranged between the backlight unit and the beam expanding film, the flat panel being configured to provide a hologram; and
a lens configured to focus a holographic image on a space.

16. The holographic display apparatus of claim 15 , wherein the lens is arranged between the backlight unit and the flat panel.

17. The holographic display apparatus of claim 15 , wherein the lens is arranged between the flat panel and the beam expanding film.

18. The holographic display apparatus of claim 15 , wherein the lens is arranged at a position where light emitted from the beam expanding film is directly incident on the lens.

19. The holographic display apparatus of claim 15 , wherein the flat panel comprises a spatial light modulator.

20. The holographic display apparatus of claim 15 , wherein the flat panel comprises a liquid crystal device (LCD), a semiconductor modulator, a digital micromirror device (DMD), or a liquid crystal on silicon (LCOS).

Assignees

• Samsung Electronics Co Ltd
• Univ Korea Res & Business Foundation Sejong Campus

Inventors

• Kim Yunhee
• Kim Hwi
• Kim Youngjae
• Song Hoon
• Lee Hongseok

Classifications

• G02B27/0944

  Diffractive optical elements, e.g. gratings, holograms (gratings per se G02B5/18; holograms used as optical elements per se G02B5/32) · CPC title

• G02B1/005 Primary

  made of photonic crystals or photonic band gap materials (photonic band-gap structures or photonic lattices in integrated optics G02B6/1225; photonic band-gap structures or photonic lattices in optical fibres G02B6/02295) · CPC title

• G03H1/2205

  using downstream optical component · CPC title

• G03H2001/221

  Element having optical power, e.g. field lens · CPC title

• G02B27/09

  Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for {(adapting the beam shape of a laser diode G02B19/0052; adapting the beam shape of an LED G02B19/0061; coupling into light guides using intermediate optical elements G02B6/4204; beam shaping specially adapted for lasers H01S3/005)} · CPC title