Virtual image display apparatus

Patent metadata

Field	Value
Publication number	US-2016124223-A1
Application number	US-201514884141-A
Country	US
Kind code	A1
Filing date	Oct 15, 2015
Priority date	Oct 29, 2014
Publication date	May 5, 2016
Grant date	—

Abstract

A virtual image display apparatus includes a first light guide that not only causes a display light flux incident through a first light incident surface to repeatedly undergo internal reflection to travel in a first direction away from the first light incident surface but also causes part of the display light flux to exit to the outside through areas of a first light exiting surface that is at least one of interfaces with the outside and extends in the first direction, a first light-incident-side diffraction grating that diffracts light incident thereon to cause the diffracted light to enter the first light guide, and a first light-exiting-side diffraction grating that diffracts light incident from the first light guide.

First claim

What is claimed is:

1 . A virtual image display apparatus comprising:
a first light guide that not only causes a display light flux incident through a first light incident surface to repeatedly undergo internal reflection to travel in a first direction away from the first light incident surface but also causes part of the display light flux to exit to the outside through areas of a first light exiting surface that is at least one of interfaces with the outside and extends in the first direction; a first light-incident-side diffraction grating that diffracts light incident thereon to cause the diffracted light to enter the first light guide; and a first light-exiting-side diffraction grating that diffracts light incident from the first light guide.

2 . The virtual image display apparatus according to claim 1 ,
wherein the first light-incident-side diffraction grating and the first light-exiting-side diffraction grating diffract incident light fluxes having the same wavelength at the same angle of diffraction.

3 . The virtual image display apparatus according to claim 1 , further comprising
a second light guide that not only causes the display light flux incident through a second light incident surface to repeatedly undergo internal reflection to travel in a second direction roughly perpendicular to the first direction but also causes part of the display light flux to exit toward the first light incident surface through areas of a second light exiting surface that is at least one of the interfaces with the outside and extends in the second direction.

4 . The virtual image display apparatus according to claim 3 , further comprising:
a second light-incident-side diffraction grating that diffracts light incident thereon to cause the diffracted light to enter the second light guide; and a second light-exiting-side diffraction grating that diffracts light incident from the second light guide.

5 . The virtual image display apparatus according to claim 4 ,
wherein the second light exiting surface and the first light incident surface are disposed in positions where the two surfaces face each other, and the second light-incident-side diffraction grating and the second light-exiting-side diffraction grating diffract incident light fluxes having the same wavelength at the same angle of diffraction.

6 . The virtual image display apparatus according to claim 1 , further comprising
a direction adjustment layer that is disposed in correspondence with the first light exiting surface and adjusts the traveling direction of the light that exits out of the first light guide.

7 . The virtual image display apparatus according to claim 1 ,
wherein the first light-exiting-side diffraction grating has a characteristic in which diffraction efficiency thereof increases in the first direction.

8 . The virtual image display apparatus according to claim 1 , further comprising
a transmitted light level adjustment layer that is disposed on at least one of the light incident side and the light exiting side of the first light-exiting-side diffraction grating and has one of a characteristic in which transmittance at which the transmitted light level adjustment layer transmits light incident thereon increases in the first direction and a characteristic in which reflectance at which the transmitted light level adjustment layer reflects the light decreases in the first direction.

9 . The virtual image display apparatus according to claim 1 ,
wherein the display light flux contains at least one type of color light having a wavelength width of 10 nm or wider.

Assignees

• Seiko Epson Corp

Inventors

• Shinbo Akira
• Yokoyama Osamu
• Yonekubo Masatoshi

Classifications

• G02B6/005

  provided by one optical element, or plurality thereof, placed on the light output side of the light guide · CPC title

• G02B27/0037

  with diffracting elements (G02B27/0056 takes precedence; holographic optical elements G02B5/32; zone systems G02B5/1876) · CPC title

• G02B2027/011

  comprising device for correcting geometrical aberrations, distortion · CPC title

• G02B6/0023

  provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source · CPC title

• G02B27/0101 Primary

  characterised by optical features (G02B27/0172 takes precedence) · CPC title