VIRTUAL IMAGE DISPLAY APPARATUS

• US 20160124223A1
• Filed: 10/15/2015
• Published: 05/05/2016
• Est. Priority Date: 10/29/2014
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: SHINBO, Akira, YOKOYAMA, Osamu, YONEKUBO, Masatoshi
• Application Number:
  US14/884,141
• Publication Number:
  US 20160124223A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 27/0037 with diffracting elements G02B27/0056 takes precedence; holographic optical elements G02B5/32; zone systems G02B5/1876
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence

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.

Claims

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.