US 12,405,474 B2
Optical system and image display apparatus
Yoshihisa Tashiro, Tochigi (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on May 16, 2024, as Appl. No. 18/665,677.
Claims priority of application No. 2023-084164 (JP), filed on May 22, 2023.
Prior Publication US 2024/0393594 A1, Nov. 28, 2024
Int. Cl. G02B 27/01 (2006.01); G02B 9/10 (2006.01); G02B 13/00 (2006.01); G02B 27/12 (2006.01)
CPC G02B 27/0172 (2013.01) [G02B 9/10 (2013.01); G02B 13/006 (2013.01); G02B 27/123 (2013.01)] 33 Claims
OG exemplary drawing
 
1. An optical system configured to guide light from a display element to an observation side, the optical system comprising:
a first lens having a first half-transmissive reflective surface provided to a surface on a display element side of the first lens; and
a second lens having a second half-transmissive reflective surface,
wherein the light from the display element transmits through the second half-transmissive reflective surface, is reflected on the first half-transmissive reflective surface, is reflected on the second half-transmissive reflective surface, transmits through the first half-transmissive reflective surface, and is guided to the observation side,
wherein one of the first lens, the second lens, and another lens has negative refractive power,
wherein the first lens has a concave surface facing the observation side, and
wherein the following inequality is satisfied:

OG Complex Work Unit Math
where fn is a focal length of the one having the negative refractive power, f is a focal length of the optical system, νdn is an Abbe number of the one having the negative refractive power based on d-line.