公开(公告)号：US20170336539A1

公开(公告)日：2017-11-23

申请号：US15157628

申请日：2016-05-18

Applicant: Google Inc.

Inventor： John D. Perreault ,  Xinda Hu ,  Yi Qin ,  Serge Bierhuizen

IPC: G02B3/08 ,  G02B27/00 ,  G02B27/01

CPC classification number: G02B3/08 ,  G02B3/04 ,  G02B5/045 ,  G02B13/18 ,  G02B27/0025 ,  G02B27/0172 ,  G02B2027/0132

Abstract: A lens assembly has two opposing surfaces, each surface introducing field curvature in a direction opposite of the field curvature introduced by the opposing surface, and thus the field curvatures introduced by the two surfaces at least partially cancel each other out, resulting in a net field curvature that provides for a substantially flat image plane or for an image plane with a specified curvature. The lens assembly may be implemented as a lens with two opposing Fresnel surfaces so that the field curvature in one direction introduced by one of the Fresnel surfaces is at least partially canceled out by the field curvature in the opposite direction as introduced by an opposing Fresnel surface. Alternatively, the lens assembly may be implemented as a lens with a positive continuous aspheric surface facing the user's eye and an opposing Fresnel surface facing the display panel.

公开(公告)号：US10215890B2

公开(公告)日：2019-02-26

申请号：US15157628

申请日：2016-05-18

Applicant: Google Inc.

Inventor： John D. Perreault ,  Xinda Hu ,  Yi Qin ,  Serge Bierhuizen

IPC: G02B3/08 ,  G02B27/00 ,  G02B27/01 ,  G02B13/18 ,  G02B3/04 ,  G02B5/04

Abstract: A lens assembly has two opposing surfaces, each surface introducing field curvature in a direction opposite of the field curvature introduced by the opposing surface, and thus the field curvatures introduced by the two surfaces at least partially cancel each other out, resulting in a net field curvature that provides for a substantially flat image plane or for an image plane with a specified curvature. The lens assembly may be implemented as a lens with two opposing Fresnel surfaces so that the field curvature in one direction introduced by one of the Fresnel surfaces is at least partially canceled out by the field curvature in the opposite direction as introduced by an opposing Fresnel surface. Alternatively, the lens assembly may be implemented as a lens with a positive continuous aspheric surface facing the user's eye and an opposing Fresnel surface facing the display panel.