# US 12,222,503 B2 · Optical arrangement for a display > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,222,503 B2 - Document ID: US12222503B2 - Status: Granted - Kind: B2 - Application number: 17/594,426 - Filed: 2020-03-17 - Published: 2022-06-16 - Granted: 2025-02-11 - Earliest claimed: 2019-04-18 - Assignees: Snap Inc. - Applicants: Snap Inc. - Inventors: Rory Thomas Alexander Mills; Ian Thomas Macken - Web page: https://patentgrep.com/patent/US12222503B2 ## CPC - G02B 17/0856: {comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors} - G02B 27/0172: {characterised by optical features} - G02B 17/086: {wherein the system is made of a single block of optical material, e.g. solid catadioptric systems} - G02B 27/0081: {with means for altering, e.g. enlarging, the entrance or exit pupil} - G02B 27/0944: {Diffractive optical elements, e.g. gratings, holograms (gratings per se G02B5/18; holograms used as optical elements per se G02B5/32)} - G02B 5/04: Prisms - G02B 2027/013: {comprising a combiner of particular shape, e.g. curvature} - G02B 2027/0178: {Eyeglass type (eyeglass details G02C)} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A folded optical arrangement to transmit an image from an image plane to a user's eye through a folded optical transmission path including a collimating element having a first optical element with optically powered surfaces and a second optical element with at least one optically powered surface to receive light from an image source and to collimate and output the light. The first optically powered surfaces and the second optically powered surface to define multiple interfaces along the folded optical path. A refractive index change at each interface controls a direction of light passing through each interface. One surface of the first optical element and the second optical element are adjacent to one another. The adjacent surfaces have dissimilar shapes and each defines an angle with a respective other surface of the relevant optical element at opposing ends of the adjacent surfaces. The opposing angles are not equal. ## Claims ### Claim 1 A folded optical arrangement for use in a display, the display to transmit an image from an image plane to a user's eye, the arrangement providing a folded optical transmission path and comprising: a collimating element having a first optical element and a second optical element, the first optical element comprising a first plurality of optically powered surfaces, and the second optical element comprising at least one optically powered surface, the collimating element configured to receive light forming the image from an image source, and to collimate and output the light, wherein the first optical element comprising the first optically powered surface is arranged to receive the light forming the image, and the second optically powered surface is reflective and arranged to receive light from the first optically powered surface, wherein the first plurality of optically powered surfaces and the at least one optically powered surface are arranged to define a plurality of interfaces along the folded optical path and wherein a refractive index change at each interface is predetermined to control a direction of light passing through each interface, and wherein one surface of the first optical element and one surface of the second optical element are adjacent to one another and the adjacent surfaces have a different shape and each define an angle with another surface of the respective optical element at an opposing end of the adjacent surfaces so as to provide opposing angles, and wherein the opposing angles are not equal. ### Claim 2 (depends on 1) The folded optical arrangement of claim 1, further comprising a pupil expanding element having a waveguide, a coupling element configured to couple light output from the collimating element into the waveguide, and a decoupling element configured to decouple light from the waveguide for output to the user's eye. ### Claim 3 (depends on 2) The folded optical arrangement of claim 2, wherein the decoupled light has a larger exit pupil than the coupled light. ### Claim 4 (depends on 1) The folded optical arrangement of claim 1, wherein the angle defined on the second optical element is less than the angle defined on the first optical element. ### Claim 5 (depends on 1) The folded optical arrangement of claim 1, further comprising a third optical element comprising at least one optically powered surface which is located between the image plane and the first optical element. ### Claim 6 (depends on 1) The folded optical arrangement of claim 1, wherein the first optical element comprises at least three optically powered surfaces. ### Claim 7 (depends on 1) The folded optical arrangement of claim 1, wherein the first optical element is a single-piece three-sided element having an elongate, substantially triangular cross-section. ### Claim 8 (depends on 1) The folded optical arrangement of claim 1, wherein the second optical element comprises at least two optically powered surfaces. ### Claim 9 (depends on 1) The folded optical arrangement of claim 1, wherein the second optical element is an optical wedge. ### Claim 10 (depends on 1) The folded optical arrangement of claim 1, wherein a surface of the first optical element is adjacent a surface of the second optical element, and the adjacent surfaces are separated by a gap. ### Claim 11 (depends on 2) The folded optical arrangement of claim 2, wherein the area over which the light is decoupled is larger than the area over which it is coupled. ### Claim 12 (depends on 2) The folded optical arrangement of claim 2, wherein an incoupling region comprises a diffraction grating and an outcoupling region comprises a diffraction grating. ### Claim 13 (depends on 1) The folded optical arrangement of claim 1, wherein at least one of the optically powered surfaces on the first optical element is described by a multiple order polynomial. ### Claim 14 (depends on 1) A display comprising a folded optical arrangement according to claim 1. ### Claim 15 (depends on 14) The display of claim 14 in the form of at least one type of display selected from display types including a head mounted display, a head worn display, and a head up display. ### Claim 16 A folded optical arrangement for use in a display, the display to transmit an image from an image plane to a user's eye, the arrangement providing a folded optical transmission path and comprising: a collimating element having a first optical element and a second optical element, the first optical element comprising a first plurality of surfaces including two or more optically powered surfaces, and the second optical element comprising a second plurality of surfaces including at least one optically powered surface, the collimating element configured to receive light forming the image from an image source, and to collimate and output the light, wherein the first optical element comprising the first optically powered surface is arranged to receive the light forming the image, and the second optically powered surface is reflective and arranged to receive light from the first optically powered surface, and a pupil expanding element having a waveguide, a coupling element configured to couple light output from the collimating element into the waveguide, and a decoupling element configured to decouple light from the waveguide for output to the user's eye, the decoupled light having a larger exit pupil than the coupled light; wherein the optically powered surfaces of the first and second optical elements are arranged to define a plurality of interfaces along the folded optical path and wherein a refractive index change at each interface is predetermined to control the direction of light passing through the or each interface, and wherein one surface of the first optical element and one surface of the second optical element are adjacent to one another and the adjacent surfaces have a different shape and each define an angle with another surface of the respective optical element at an opposing end of the adjacent surfaces so as to provide first and second angles, and wherein the first and second angles are not equal. ### Claim 17 (depends on 16) The folded optical arrangement of claim 16, wherein the second angle defined on the second optical element is less than the first angle defined on the first optical element. ### Claim 18 (depends on 16) A display comprising the folded optical arrangement of claim 16, the display being in the form of at least one type of display selected from displays including a head mounted display, a head worn display, a head up display, googles, glasses, a helmet, a helmet visor, and a gaming headset. ### Claim 19 A folded optical arrangement for use in a display, the display to transmit an image from an image plane to a user's eye, the folded optical arrangement providing a folded optical transmission path and comprising: a collimating element having a first optical element and a second optical element, the first optical element comprising a first plurality of surfaces including three or more optically powered surfaces, and the second optical element comprising a second plurality of surfaces including at least two optically powered surfaces, the collimating element configured to receive light forming the image from an image source, and to collimate and output the light; and a third optical element comprising at least one optically powered surface which is located between the image plane and the first optical element; wherein the first optical element comprising a first optically powered surface is arranged to receive the light forming the image, a second optically powered surface which is reflective, and arranged to receive light from the first optically powered surface, and a third optically powered surface which is configured to receive light reflected by the second optically powered surface and reflect it back towards the second optically powered surface, wherein the optically powered surfaces of at least the first and second optical elements are arranged to define a plurality of interfaces along the folded optical path and wherein a refractive index change at each interface is predetermined to control the direction of light passing through the or each interface, and wherein one surface of the first optical element and one surface of the second optical element are adjacent to one another and the adjacent surfaces have a different shape and each define an angle with another surface of the respective optical element at an opposing end of the adjacent surfaces so as to provide first and second angles, and wherein the second angle defined on the second optical element is less than the first angle defined on the first optical element. ### Claim 20 (depends on 19) A display comprising the folded optical arrangement of claim 19, the display being in the form of at least one type of display selected from display types including a head mounted display, a head worn display, a head up display, googles, glasses, a helmet, a helmet visor, and a gaming headset.