Waveguide, waveguide manufacturing apparatus, waveguide manufacturing method, and video display device using the same

Patent metadata

Field	Value
Publication number	US-11513473-B2
Application number	US-202015931653-A
Country	US
Kind code	B2
Filing date	May 14, 2020
Priority date	Aug 23, 2019
Publication date	Nov 29, 2022
Grant date	Nov 29, 2022

Abstract

Provided is a waveguide having a light diffraction unit that diffracts incident light by a multiplex-recorded hologram, in which, in the light diffraction unit, a plurality of holograms having different angles with respect to an incident surface of the waveguide are formed, and when certain parallel light beams are incident, different wavelengths are diffracted by the plurality of holograms.

First claim

What is claimed is:

1. A waveguide comprising a light diffraction unit that diffracts incident light by a multiplex-recorded hologram,
wherein, in the light diffraction unit, a plurality of holograms having different angles with respect to an incident surface of the waveguide are formed, and when certain parallel light beams are incident, different wavelengths are diffracted by the plurality of holograms, and
wherein the waveguide further comprises a transmission-type incident prism and an internal plane reflection prism.

2. The waveguide according to claim 1 , further comprising a transmission-type incident prism.

3. The waveguide according to claim 1 , further comprising an internal plane reflection prism.

4. The waveguide according to claim 1 , wherein the light diffraction unit has a two-layer structure of at least a cover layer and a medium layer, and a ratio of wavelength dependency of refractive indexes of the cover layer and the medium layer is not constant.

5. A manufacturing apparatus for a waveguide having a light diffraction unit that diffracts incident light by a multiplex-recorded hologram, comprising:
a light source unit;
a light splitting unit;
a light reflection unit;
a recording prism; and
a recording medium interposed between the recording prism,
wherein lights split by the light splitting unit intersect again by rotation of the light reflection unit to form an interference fringe plane that is multiplex-recorded in the recording medium, and
wherein the recording prism has a rotation mechanism, and a central axis of the rotation mechanism is in the interference fringe plane.

6. The waveguide manufacturing apparatus according to claim 5 , wherein the rotation mechanism is a gonio stage.

7. The waveguide manufacturing apparatus according to claim 5 , further comprising a uniaxial stage that moves positions of the recording prism to a position where the lights split by the light splitting unit that moves by the rotation of the light reflection unit intersect.

8. The waveguide manufacturing apparatus according to claim 5 , further comprising a uniaxial stage that moves the light reflection unit so as to move positions of the recording medium to a position where the lights split by the light splitting unit that moves by the rotation of the light reflection unit intersect.

9. A method of manufacturing a waveguide having a light diffraction unit that diffracts incident light by a multiplex-recorded hologram, comprising:
forming interference fringes which are multiplex-recorded in a recording medium interposed by recording prism by allowing two recording lights to intersect by rotation of a light reflection unit; and
recording the interference fringes at a desired angle by tilting the recording medium in a rotation direction around an axis in a plane of the interference fringes.

10. The method of manufacturing a waveguide according to claim 9 , wherein a position of the recording medium is moved to a position where the recording lights that move by the rotation of the light reflection unit intersect.

11. The method of manufacturing a waveguide according to claim 9 , wherein the light reflection unit is moved so that a position of the recording medium is moved to a position where the recording lights that move by the rotation of the light reflection unit intersect.

12. A video display device comprising:
a video input unit;
an image quality correction unit that corrects color and brightness of a video to be displayed on the basis of a video data transmitted from the video input unit; and
a video projection unit that emits video light corrected by the image quality correction unit,
wherein the waveguide according to claim 1 is used as an optical system for propagating the video light emitted from the video projection unit to eyes of a user.

13. A waveguide comprising a light diffraction unit that diffracts incident light by a multiplex-recorded hologram,
wherein, in the light diffraction unit, a plurality of holograms having different angles with respect to an incident surface of the waveguide are formed, and when certain parallel light beams are incident, different wavelengths are diffracted by the plurality of holograms, and
wherein the light diffraction unit has a two-layer structure of at least a cover layer and a medium layer, and a ratio of wavelength dependency of refractive indexes of the cover layer and the medium layer is not constant.

Assignees

• Hitachi Lg Data Storage Inc

Inventors

• Utsugi Takeru
• Yamakawa Hiromichi

Classifications

• G03H2270/55

  being an optical element, e.g. spectacles · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B6/0053

  Prismatic sheet or layer; Brightness enhancement element, sheet or layer · CPC title

• G02B2027/0174

  holographic · CPC title

• G02B2027/0123

  comprising devices increasing the field of view · CPC title