# US 10,082,674 B2 · Viewer with enhanced depth perception > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,082,674 B2 - Document ID: US10082674B2 - Status: Granted - Kind: B2 - Application number: 14/912,290 - Filed: 2014-08-15 - Published: 2016-07-14 - Granted: 2018-09-25 - Earliest claimed: 2013-08-15 - Assignees: Vision Engineering Limited - Applicants: Vision Engineering Limited - Inventors: Graham Peter Francis Mercer - Web page: https://patentgrep.com/patent/US10082674B2 ## CPC - G02B 17/08: Catadioptric systems {(used in non-imaging applications G02B19/00)} - G02B 17/0856: {comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors} - G02B 27/027: {comprising magnifying means (G02B27/023, G02B27/025, G02B27/04, G02B27/06 and G02B27/08 take precedence)} - G02B 27/144: {using partially transparent surfaces without spectral selectivity (G02B27/147 takes precedence)} - G02B 30/26: of the autostereoscopic type - G02B 30/40: giving the observer of a single two-dimensional [2D] image a perception of depth - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A viewer for viewing an object under magnification, the viewer comprising: an objective lens for producing an image of an object located at an object plane and having a radial extent defined by an aperture stop; a partially-transmissive reflector for allowing transmission of light therethrough from the objective lens to a mirror arrangement and providing for reflection of light which is returned thereto from the mirror arrangement; a mirror arrangement which receives a light component from the partially-transmissive reflector, and is located such that a focussed image of the object is produced at the mirror arrangement and light received by the mirror arrangement is reflected back to the partially-transmissive reflector and relayed to produce an image of the object; a viewing lens arrangement for producing an optical image of the object which is viewable by an observer at an exit pupil at a viewing plane; wherein the objective lens has a beam path angle (a) as defined by a distance from the object plane to the objective lens and a radial extent of the aperture stop; wherein the viewer has a viewing angle (β) as defined by a distance along an optical axis from the mirror arrangement to the viewing plane and a radial extent of the exit pupil at the viewing plane; wherein the viewer is configured such that a displacement ratio of the beam path angle (a) to the viewing angle (β) is at least 3:1, whereby the observer is provided with a greater change in depth perception of the object being observed relative to an extent of displacement of a head of the observer. ## Claims ### Claim 1 A viewer for viewing an object under magnification, the viewer comprising: an objective lens for producing an image of an object located at an object plane and having a radial extent defined by an aperture stop; a partially-transmissive reflector for allowing transmission of light therethrough from the objective lens to a mirror arrangement and providing for reflection of light which is returned thereto from the mirror arrangement; a mirror arrangement which receives a light component from the partially-transmissive reflector, and is located such that a focussed image of the object is produced at the mirror arrangement and light received by the mirror arrangement is reflected back to the partially-transmissive reflector and relayed to produce an image of the object; a viewing lens arrangement for producing an optical image of the object which is viewable by an observer at an exit pupil at a viewing plane; wherein the objective lens has a beam path angle (α) which is an angle subtended from a point where an optical axis of the objective lens meets the object plane and defined by a distance along the optical axis from the object plane to the objective lens and a radial extent of the aperture stop; wherein the viewer has a viewing angle (β) which is an angle subtended from a point on the mirror arrangement at an optical axis of the mirror arrangement and defined by a distance along the optical axis from the mirror arrangement to the viewing plane and a radial extent of the exit pupil at the viewing plane; wherein the viewer is configured such that a displacement ratio of the beam path angle (α) to the viewing angle (β) is at least 3:1. ### Claim 2 (depends on 1) The viewer of claim 1, wherein the displacement ratio of the beam path angle (α) to the viewing angle (β) is at least 4:1. ### Claim 3 (depends on 1) The viewer of claim 1, wherein the displacement ratio of the beam path angle (α) to the viewing angle (β) is at least 5:1. ### Claim 4 (depends on 1) The viewer of claim 1, wherein the displacement ratio of the beam path angle (α) to the viewing angle (β) is at least 6:1. ### Claim 5 (depends on 1) The viewer of claim 1, wherein the displacement ratio of the beam path angle (α) to the viewing angle (β) is at least 8:1. ### Claim 6 (depends on 1) The viewer of claim 1, wherein the displacement ratio of the beam path angle (α) to the viewing angle (β) is at least 10:1. ### Claim 7 (depends on 1) The viewer of claim 1, wherein the displacement ratio of the beam path angle (α) to the viewing angle (β) is at least 12:1. ### Claim 8 (depends on 1) The viewer of claim 1, wherein the displacement ratio of the beam path angle (α) to the viewing angle (β) is at least 13:1. ### Claim 9 (depends on 1) The viewer of claim 1, wherein the beam path angle (α) is at least 6 degrees. ### Claim 10 (depends on 1) The viewer of claim 1, wherein the beam path angle (α) is at least 8 degrees. ### Claim 11 (depends on 1) The viewer of claim 1, wherein the beam path angle (α) is at least 9 degrees. ### Claim 12 (depends on 1) (Previously Presented The viewer of claim 1, wherein the beam path angle (α) is at least 10 degrees. ### Claim 13 (depends on 1) The viewer of claim 1, wherein the beam path angle (α) is at least 12 degrees. ### Claim 14 (depends on 1) The viewer of claim 1, wherein the beam path angle (α) is at least 13 degrees. ### Claim 15 (depends on 1) The viewer of claim 1, wherein the viewing angle (β) is not more than 2 degrees. ### Claim 16 (depends on 1) The viewer of claim 1, wherein the viewing angle (β) is not more than 1.5 degrees. ### Claim 17 (depends on 1) The viewer of claim 1, wherein the light component received by the mirror arrangement passes through the partially-transmissive reflector. ### Claim 18 (depends on 1) The viewer of claim 1, wherein the light received from the mirror arrangement and relayed by the partially-transmissive reflector is reflected by the partially-transmissive reflector. ### Claim 19 (depends on 1) The viewer of claim 1, wherein the objective lens is located at a distance of less than 120 mm along the optical axis from the object plane. ### Claim 20 (depends on 1) The viewer of claim 1, wherein the objective lens is located at a distance of less than 100 mm along the optical axis from the object plane. ### Claim 21 (depends on 1) The viewer of claim 1, wherein the objective lens is located at a distance of less than 80 mm along the optical axis from the object plane. ### Claim 22 (depends on 1) The viewer of claim 1, wherein the objective lens is located at a distance of less than 60 mm along the optical axis from the object plane. ### Claim 23 (depends on 1) The viewer of claim 1, wherein the aperture stop has an aperture diameter of at least 30 mm. ### Claim 24 (depends on 1) The viewer of claim 1, wherein the aperture stop has an aperture diameter of at least 35 mm. ### Claim 25 (depends on 1) The viewer of claim 1, wherein the aperture stop has an aperture diameter of at least 40 mm. ### Claim 26 (depends on 1) The viewer of claim 1, wherein the partially-transmissive reflector comprises a semi-transmissive reflector. ### Claim 27 (depends on 26) The viewer of claim 26, wherein the partially-transmissive reflector comprises a partially-transmissive mirror or a half-silvered planar mirror. ### Claim 28 (depends on 1) The viewer of claim 1, wherein an optical center of the viewer as provided by the optical axis at the partially-transmissive reflector is located at a distance of at least 150 mm along the optical axis from the viewing plane. ### Claim 29 (depends on 1) The viewer of claim 1, wherein an optical center of the viewer as provided by the optical axis at the partially-transmissive reflector is located at a distance of at least 180 mm along the optical axis from the viewing plane. ### Claim 30 (depends on 1) The viewer of claim 1, wherein an optical center of the viewer as provided by the optical axis at the partially-transmissive reflector is located at a distance of at least 200 mm along the optical axis from the viewing plane. ### Claim 31 (depends on 1) The viewer of claim 1, wherein an optical center of the viewer as provided by the optical axis at the partially-transmissive reflector is located at a distance of at least 250 mm along the optical axis from the viewing plane. ### Claim 32 (depends on 1) The viewer of claim 1, wherein the exit pupil at the viewing plane has a diameter of not more than 30 mm. ### Claim 33 (depends on 1) The viewer of claim 1, wherein the exit pupil at the viewing plane has a diameter of not more than 25 mm. ### Claim 34 (depends on 1) The viewer of claim 1, further comprising: an illuminator which includes a plurality of light sources for illuminating the object which are offset from the optical axis of the viewer. ### Claim 35 (depends on 34) The viewer of claim 34, wherein the light sources comprise point light sources or LEDs, which are arranged around the optical axis. ### Claim 36 (depends on 1) The viewer of claim 1, further comprising: a zoom objective which comprises the objective lens and a plurality of additional lenses. ### Claim 37 (depends on 1) The viewer of claim 1, wherein the partially-transmissive reflector is a beam splitter for splitting light from the objective lens to have first and second light components, the first-mentioned mirror arrangement receiving the first light component from the beam splitter, and further comprising: a second mirror arrangement which receives the second light component from the beam splitter and is located such that a focussed second image of the object is produced at the second mirror arrangement and light received by the second mirror arrangement is reflected back to the beam splitter and relayed to produce an image of the object; wherein the mirror arrangements are oriented such that pupil centers of the exit pupils as relayed by the respective mirror arrangements are offset, corresponding to an interpupillary spacing of the observer, and the viewing lens arrangement relays both of the exit pupils, thereby providing that the exit pupils from the respective mirror arrangements are relayed to respective ones of the eyes of the observer and providing different stereo parallax views of the object to each eye of the observer. ### Claim 38 (depends on 37) The viewer of claim 37, wherein the light component received by the second mirror arrangement is reflected by the beam splitter. ### Claim 39 (depends on 37) The viewer of claim 37, wherein the light received from the second mirror arrangement and relayed by the beam splitter passes through the beam splitter. ### Claim 40 (depends on 1) The viewer of claim 1, wherein any or each mirror arrangement comprises a mirror and a spherical lens at the surface of the mirror. ### Claim 41 (depends on 40) The viewer of claim 40, wherein the mirror comprises a planar mirror. ### Claim 42 (depends on 40) The viewer of claim 40, wherein the mirror comprises an aspherical mirror. ### Claim 43 (depends on 1) The viewer of claim 1, wherein any or each mirror arrangement comprises a concave mirror.