# US 11,906,728 B2 · Pixel shifting device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,728 B2 - Document ID: US11906728B2 - Status: Granted - Kind: B2 - Application number: 17/360,193 - Filed: 2021-06-28 - Published: 2022-10-20 - Granted: 2024-02-20 - Earliest claimed: 2021-04-16 - Assignees: Microsoft Technology Licensing, LLC - Applicants: Microsoft Technology Licensing, LLC - Inventors: Utku Baran; Wyatt Owen Davis; Fei Chen - Web page: https://patentgrep.com/patent/US11906728B2 ## CPC - G02B 26/0858: {the reflecting means being moved or deformed by piezoelectric means} - G02B 26/0883: {the refracting element being a prism} - G02B 5/32: Holograms used as optical elements - G02B 7/1805: {for prisms (G02B7/181 takes precedence)} - G02B 26/0875: {by means of one or more refracting elements} - G02B 27/0172: {characterised by optical features} - G02B 2027/0147: {comprising a device modifying the resolution of the displayed image} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract Examples are disclosed that relate to pixel-shifting devices for increasing display resolution. An example pixel-shifting device comprises an outer frame, an inner frame coupled to the outer frame via a flexure, a path-shifting optical element mounted to the inner frame, and one or more piezoelectric actuators configured to drive motion of the inner frame. ## Claims ### Claim 1 A pixel-shifting device, comprising: an outer frame; an inner frame coupled to the outer frame via a flexure positioned along a side of the inner frame; a path-shifting optical element mounted to the inner frame; and one or more piezoelectric actuators each coupled to the outer frame and also coupled to the inner frame by a corresponding transmission comprising a curved shape, each piezoelectric actuator being and configured to drive motion of the inner frame by transmitting movement to the inner frame via the corresponding transmission to shift a plurality of pixels of a display image by a fraction of a pixel. ### Claim 2 (depends on 1) The pixel-shifting device of claim 1, wherein each piezoelectric actuator comprises a thin film of a piezoelectric material deposited and patterned on the structure forming the inner and outer frames. ### Claim 3 (depends on 2) The pixel-shifting device of claim 2, further comprising a plurality of flexures, wherein each flexure of the plurality of flexures is positioned along a corresponding side of the inner frame at a location spaced from a center of the corresponding side. ### Claim 4 (depends on 1) The pixel-shifting device of claim 1, further comprising a feedback sensor configured to sense position feedback from the path-shifting optical element, and a control circuit configured to control power provided to a driver of the piezoelectric actuators based upon the position feedback from the path-shifting optical element. ### Claim 5 (depends on 1) The pixel-shifting device of claim 1, wherein the path-shifting optical element comprises a prism. ### Claim 6 (depends on 1) The pixel-shifting device of claim 1, wherein the path-shifting optical element comprises a holographic optical element. ### Claim 7 A display device, comprising: an image producing element comprising a plurality of pixels, the image producing element being configured to produce a display image; and a pixel-shifting device comprising an outer frame, an inner frame coupled to the outer frame via a flexure positioned along a side of the inner frame, a refractive optic mounted to the inner frame, and a plurality of piezoelectric actuators each coupled to the outer frame and also coupled to the inner frame by a corresponding transmission comprising a curved shape; and a controller configured to control the plurality of piezoelectric actuators to control an angle of the refractive optic relative to the outer frame by transmitting movement to the inner frame via the corresponding transmission to shift the display image by a fraction of a pixel. ### Claim 8 (depends on 7) The display device of claim 7, further comprising a plurality of flexures, wherein each flexure of the plurality of flexures is positioned along a corresponding perimeter side of the inner frame spaced from a center of the corresponding perimeter side. ### Claim 9 (depends on 7) The display device of claim 7, further comprising a feedback sensor configured to sense position feedback from the refractive optic, and a control circuit configured to control power provided to a driver of the piezoelectric actuators based upon the position feedback from the refractive optic. ### Claim 10 (depends on 7) The display device of claim 7, wherein the refractive optic comprises a prism. ### Claim 11 (depends on 7) The display device of claim 7, wherein the refractive optic comprises a holographic refractor. ### Claim 12 (depends on 7) The display device of claim 7, wherein the display device is a head-mounted display device. ### Claim 13 Enacted on a display device comprising a pixel-shifting device including a refractive optic and a piezoelectric actuation system, a method of displaying an image comprising a plurality of image subframes that are displayed in a time-sequential manner, the method comprising displaying a first image subframe with a first voltage applied to a piezoelectric element coupled to an outer frame of the pixel-shifting device; and displaying a second image subframe with a second voltage applied to the piezoelectric element of the pixel-shifting device, the second voltage being different than the first voltage, to rotate the refractive optic relative to the outer frame by transmitting movement of the outer frame caused by the piezoelectric element to an inner frame via a curved transmission and thereby shift pixel positions in the second image subframe from corresponding pixel positions in the first image subframe by a fraction of a pixel. ### Claim 14 (depends on 13) The method of claim 13, wherein the display device comprises a head-mounted display device. ### Claim 15 (depends on 13) The method of claim 13, wherein rotating the refractive optic comprises rotating the refractive optic around a diagonally oriented axis. ### Claim 16 (depends on 13) The method of claim 13, further comprising utilizing a closed-loop feedback circuit to control an angle of the refractive optic. ### Claim 17 (depends on 16) The method of claim 16, wherein the closed-loop feedback circuit compares a feedback signal to a square wave control signal. ### Claim 18 (depends on 13) The method of claim 13, wherein rotating the refractive optic comprises rotating the refractive optic about two different axes.