# US 2021/0240038 A1 · Spatially varying polarizer for display backlight > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0240038 A1 - Document ID: US20210240038A1 - Status: Published application - Kind: A1 - Application number: 17/164,284 - Filed: 2021-02-01 - Published: 2021-08-05 - Earliest claimed: 2020-02-03 - Assignees: Valve Corporation - Applicants: Valve Corporation - Inventors: Joshua Mark Hudman - Web page: https://patentgrep.com/patent/US20210240038A1 ## CPC - G02F 1/133538: {with spatial distribution of the polarisation direction} - G02F 1/133615: {Edge-illuminating devices, i.e. illuminating from the side} - G02B 6/0041: {provided in the bulk of the light guide} - G02B 6/0056: {for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements} - G02B 6/0058: {varying in density, size, shape or depth along the light guide} - G02F 1/133536: {Reflective polarizers (G02F1/13362 takes precedence)} - G02F 1/133631: {with a spatial distribution of the retardation value} - G02F 1/133636: {with twisted orientation, e.g. comprising helically oriented LC-molecules or a plurality of twisted birefringent sublayers} - G02F 1/13362: {providing polarized light, e.g. by converting a polarisation component into another one} - G02F 1/133633: {using mesogenic materials} - G02F 1/13471: {in which all the liquid crystal cells or layers remain transparent, e.g. FLC, ECB, DAP, HAN, TN, STN, SBE-LC cells (G02F1/13475 takes precedence)} - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract Systems and methods for providing a display for an electronic device that includes a liquid crystal display panel assembly, a backlight assembly that includes a light source, and a spatially varying polarizer that provides phase retardation that varies as a function of propagation length away from the light source. The display may also include a linear polarizer and other optical components that improve the efficiency of the backlight assembly, thereby reducing power consumption, cost, space requirements, and provide other advantages. ## Claims ### Claim 1 A display, comprising: a non-emissive display panel assembly; a backlight assembly comprising a light source; and a spatially varying polarizer positioned between the non-emissive display panel assembly and the backlight assembly, the spatially varying polarizer having a polarization that spatially varies as a function of propagation length away from the light source. ### Claim 2 (depends on 1) The display of claim 1 wherein the spatially varying polarizer comprises a multi-twist retarder. ### Claim 3 (depends on 1) The display of claim 1 wherein the spatially varying polarizer provides no retardation at a proximal end near the light source and provides quarter-wavelength retardation at a distal end opposite the proximal end. ### Claim 4 (depends on 1) The display of claim 1 wherein the retardation of the spatially varying polarizer varies linearly or non-linearly between a proximal end near the light source and a distal end opposite the proximal end. ### Claim 5 (depends on 1) The display of claim 1, further comprising: a linear polarizer positioned between the spatially varying polarizer and the non-emissive display panel assembly. ### Claim 6 (depends on 5) The display of claim 5 wherein the linear polarizer comprises dual brightness enhancement film (DBEF). ### Claim 7 (depends on 1) The display of claim 1, further comprising: control circuitry operatively coupled to the spatially varying polarizer, the control circuitry operative to selectively adjust the retardation provided by the spatially varying polarizer. ### Claim 8 (depends on 1) The display of claim 1 wherein the backlight assembly comprises a light guide plate that includes light-scattering features. ### Claim 9 (depends on 1) The display of claim 1 wherein the backlight assembly comprises a light guide plate that does not include any light-scattering features. ### Claim 10 (depends on 1) The display of claim 1 wherein the backlight assembly comprises a wedge-shaped light guide plate. ### Claim 11 (depends on 1) The display of claim 1 wherein the non-emissive display panel assembly comprises a liquid crystal display panel assembly. ### Claim 12 (depends on 1) The display of claim 1 wherein the light source comprises an array of light emitting diodes. ### Claim 13 A display, comprising: a non-emissive display panel assembly; a backlight assembly comprising a light guide plate and a light source that provides light to an edge of the light guide plate; a reflective polarizer positioned between the non-emissive display panel assembly and the light guide plate; and a spatially varying polarizer positioned between the reflective polarizer and the light guide plate, the spatially varying polarizer having a polarization that spatially varies as a function of propagation length away from the light source. ### Claim 14 (depends on 13) The display of claim 13 wherein the spatially varying polarizer comprises a multi-twist retarder. ### Claim 15 (depends on 13) The display of claim 13 wherein the reflective polarizer comprises a dual brightness enhancement film (DBEF). ### Claim 16 (depends on 13) The display of claim 13 wherein the spatially varying polarizer provides no retardation at a proximal end near the light source and provides quarter-wavelength retardation at a distal end opposite the proximal end. ### Claim 17 (depends on 13) The display of claim 13 wherein the light guide plate includes light-scattering features. ### Claim 18 (depends on 13) The display of claim 13 wherein the light guide plate does not include any light-scattering features. ### Claim 19 (depends on 13) The display of claim 13 wherein the light source comprises an array of light emitting diodes. ### Claim 20 (depends on 13) The display of claim 13, wherein the display is a display of a head-mounted display device, a television, a laptop computer, a smartphone, a tablet computer, a computer monitor, or a wearable electronic device.