US 12,468,081 B2
Optical element and virtual image display device
Osamu Yokoyama, Shiojiri (JP); Atsushi Saito, Chino (JP); and Toshiyuki Noguchi, Shiojiri (JP)
Assigned to SEIKO EPSON CORPORATION, Tokyo (JP)
Filed by SEIKO EPSON CORPORATION, Tokyo (JP)
Filed on Jul. 28, 2022, as Appl. No. 17/876,494.
Claims priority of application No. 2021-124981 (JP), filed on Jul. 30, 2021.
Prior Publication US 2023/0033943 A1, Feb. 2, 2023
Int. Cl. G02B 5/00 (2006.01); G02B 5/32 (2006.01); G02B 27/01 (2006.01)
CPC G02B 5/32 (2013.01) [G02B 27/0172 (2013.01); G02B 2027/0174 (2013.01); G02B 2027/0178 (2013.01)] 9 Claims
OG exemplary drawing
 
1. An optical element, comprising:
a substrate;
a first hologram element provided on one side of the substrate;
a second hologram element provided on another side of the substrate;
a third hologram element and a fourth hologram element that correspond to a second wavelength band, the second wavelength band being a shorter wavelength band than the first wavelength band; and
a fifth hologram element and a sixth hologram element that correspond to a third wavelength band, the third wavelength band being a longer wavelength band than the first wavelength band, wherein
the first hologram element includes a first hologram layer that diffracts part of incident light in a first wavelength band and that transmits another part of the incident light in the first wavelength band, and
the second hologram element includes a second hologram layer that diffracts, toward the first hologram layer, part of the light in the first wavelength band, transmitted through the first hologram layer, and that transmits another part of the light in the first wavelength band, transmitted through the first hologram layer.