Ghost image elimination of doe using fourier optics method

Patent metadata

Field	Value
Publication number	US-11209586-B2
Application number	US-201715843352-A
Country	US
Kind code	B2
Filing date	Dec 15, 2017
Priority date	Dec 15, 2016
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

A see-through image display system having a DOE often has undesirable light or so called ghost images due to the quantization of saw tooth shape of DOE surface. This invention provides ways to eliminate ghost images.

First claim

We claim:

1. A see-through display system comprising:
an eyeglass lens and
a single see-through diffractive optical element (DOE) attached to the eyeglass lens wherein a spectrum of a Fourier transform of a surface shape of said single DOE is converted from a phase function to a sliced phase function therefore having a single peak within a viewing angle, and other peaks outside of the viewing angle of the eyeglass lens, for looking directly through the eyeglass lens attached with the single DOE on an image through a reflected light of an image light projected and guided by optical elements surrounding a human face to project to a tilted mirror for reflecting the reflected light of the image onto the DOE on the eyeglass lens wherein the reflected light projects the single peak from the single DOE for perceiving an image of the image light without ghost images.

2. The see-through display system of claim 1 wherein:
the surface shape of the single DOE is disposed on a semiconductor wafer comprises a plurality of saw tooth with a randomized pitch between adjacent saw tooth to reduce peaks of the spectrum of the Fourier transform of the surface shape of the single DOE other than the single peak of the spectrum of the Fourier transform within the viewing angle of the eyeglass lens.

3. The see-through display system of claim 1 wherein:
the surface shape of the single DOE is designed and formed to add a negative spectrum of the Fourier transform to reduce peaks of the spectrum of the Fourier transform other than the single peak of the spectrum of the Fourier transform within the viewing angle of the eyeglass lens.

4. The see-through display system of claim 1 wherein:
the surface shape of the single DOE is designed to have a phase shift function to reduce peaks of the spectrum of the Fourier transform other than the single peak of the spectrum of the Fourier transform within the viewing angle of the eyeglass lens.

5. A display system comprising:
a viewing lens having a viewing angle; and
a single DOE attached to the viewing lens to focus light beams, wherein a surface shape of said single DOE is converted from a phase function to a sliced phase function therefore a spectrum of a Fourier transform of the surface shape of said single DOE having a single peak within the viewing angle, and other peaks outside of the viewing angle of the viewing lens, for looking directly through the viewing lens attached with the single DOE on an image through a reflected light of an image light projected and guided by optical elements surrounding a human face to project to a tilted mirror for reflecting the reflected light of the image onto the DOE on the viewing lens wherein the reflected light projects the single peak from the single DOE for perceiving an image of the image light without ghost images.

6. The display system of claim 5 wherein:
the surface shape of the single DOE is disposed on a semiconductor wafer comprises a plurality of saw tooth with a randomized pitch between adjacent saw tooth to reduce peaks of the spectrum of the Fourier transform of the surface shape of single DOE other than the single peak of the spectrum of the Fourier transform.

7. The display system of claim 5 wherein:
the surface shape of the single DOE is designed and formed to add a negative spectrum of the Fourier transform to reduce peaks of the spectrum of the Fourier transform other than the single peak of the spectrum of the Fourier transform.

8. The display system of claim 5 wherein:
the surface shape of the single DOE is designed to have a phase shift function to reduce peaks of the spectrum of the Fourier transform other than the single peak of the spectrum of the Fourier transform for looking through the eyeglass lens on the image.

Assignees

• Ishii Fusao
• Nakanishi Mikiko
• Takahashi Kazuhiko
• Aburakawa Yuji
• Murakami Keiichi
• Ntt Docomo Inc

Inventors

• Ishii Fusao
• Nakanishi Mikiko
• Takahashi Kazuhiko
• Aburakawa Yuji
• Murakami Keiichi

Classifications

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B27/18

  for optical projection, e.g. combination of mirror and condenser and objective {(photographic, cine and overhead projectors G03B21/00; photographic projection printing G03B27/32; photolithographic projectors G03F7/20; projection television H04N5/74; colour projection television H04N9/31)} · CPC title

• G02B6/0031 Primary

  Reflecting element, sheet or layer · CPC title

• G02B2027/0174

  holographic · CPC title

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · CPC title