US 11,874,470 B2
Display apparatus having wide viewing window
Sunil Kim, Seoul (KR); Druzhin Vladislav, Moscow (RU); Malinina Polina, Moscow (RU); Bongsu Shin, Seoul (KR); and Dubynin Sergey, Moscow (RU)
Assigned to SAMSUNG ELECTRONICS CO., LTD., Suwon-si (KR)
Filed by SAMSUNG ELECTRONICS CO., LTD., Suwon-si (KR)
Filed on Sep. 29, 2022, as Appl. No. 17/956,376.
Application 17/956,376 is a continuation of application No. 16/833,831, filed on Mar. 30, 2020, granted, now 11,487,117.
Claims priority of application No. 10-2019-0133262 (KR), filed on Oct. 24, 2019.
Prior Publication US 2023/0032297 A1, Feb. 2, 2023
Int. Cl. G02B 27/01 (2006.01); G02B 5/32 (2006.01)
CPC G02B 27/0172 (2013.01) [G02B 5/32 (2013.01); G02B 27/0149 (2013.01); G02B 2027/015 (2013.01); G02B 2027/0123 (2013.01); G02B 2027/0174 (2013.01); G02B 2027/0178 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A display apparatus comprising:
an image forming apparatus configured to form an image;
a projection optical system configured to project the image formed by the image forming apparatus; and
a combining optical system configured to provide the image projected from the projection optical system combined with light from an external landscape,
wherein the combining optical system is configured to divide the image projected from the projection optical system into same images and focus the same images on different positions,
wherein the combining optical system comprises a first holographic optical element and a second holographic optical element sequentially provided along an optical path of the image projected from the projection optical system,
wherein the first holographic optical element is configured to focus the image projected from the projection optical system to a first position and to form a first image on the first position,
wherein the second holographic optical element is configured to focus the image projected from the projection optical system and transmitted by the first holographic optical element to a second position different from the first position and to form a second image on the second position,
wherein the first holographic optical element and the second holographic optical element have a form of plate and are disposed in parallel to each other,
wherein the first holographic optical element comprises a first surface configured to diffract a portion of incident light and transmit remaining portion of the incident light, and a second surface opposite the first surface and configured to transmit incident light,
wherein the first holographic optical element comprises a reflective holographic optical element configured to diffract incident light that is incident on the first surface and to focus the incident light that is diffracted in a space facing the first surface, and
wherein the first image and the second image are identical to each other.