# US 11,442,218 B2 · Color liquid crystal displays and display backlights > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,442,218 B2 - Document ID: US11442218B2 - Status: Granted - Kind: B2 - Application number: 16/791,702 - Filed: 2020-02-14 - Published: 2020-08-20 - Granted: 2022-09-13 - Earliest claimed: 2019-02-15 - Assignees: Intematix Corporation - Applicants: Intematix Corporation - Inventors: Xianglong Yuan; Yi-Qun Li - Web page: https://patentgrep.com/patent/US11442218B2 ## CPC - G02B 6/005: {provided by one optical element, or plurality thereof, placed on the light output side of the light guide} - C09K 11/616: {with alkali or alkaline earth metals} - C09K 11/675: {with alkali or alkaline earth metals} - C09K 11/7731: {with alkaline earth metals} - C09K 11/886: {with rare earth metals} - G02F 1/133509: {Filters, e.g. light shielding masks} - G02F 1/133603: {with LEDs} - G02F 1/133606: {including a specially adapted diffusing, scattering or light controlling members} - G02F 1/133611: {including means for improving the brightness uniformity} - G02F 1/133521: {Interference filters} - G02F 1/133614: {using photoluminescence, e.g. phosphors illuminated by UV or blue light} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - 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 ## Abstract There is provided a display backlight (604), including an excitation source (644) for generating blue light (650); and a wavelength converter (654) being a unitary construction including a combination of a wavelength selective filter layer (658) bonded to a photoluminescence layer (660), where the photoluminescence layer (658) includes a green photoluminescence material and a red photoluminescence material; and where the wavelength selective filter layer (658) is transmissive to blue light and reflective to green and red light. ## Claims ### Claim 1 A display comprising: a display panel and a backlight, wherein the backlight comprises a blue light excitation source and a multi-layer wavelength converter film, wherein the multi-layer wavelength converter film comprises a wavelength selective filter film layer and a photoluminescence film layer, wherein the photoluminescence film layer comprises a light transmissive polymeric binder material incorporating a green photoluminescence material and a red photoluminescence material; and wherein the wavelength selective filter film layer is transmissive to blue light and is reflective to green and red light, wherein the multi-layer wavelength converter film is positioned between the blue light excitation source and the display panel, and wherein the multi-layer wavelength converter film is a unitary construction, wherein: the photoluminescence film layer is fabricated directly onto the wavelength selective filter film layer having no air gap between the layers; or the photoluminescence film layer is fabricated separately to the wavelength selective film layer and directly bonded to the wavelength selective film layer with a light transmissive material with no air gaps between the layers. ### Claim 2 (depends on 1) The display of claim 1, wherein the photoluminescence film layer is multi-layered having a first film layer incorporating the green photoluminescence material and a second film layer incorporating the red photoluminescence material. ### Claim 3 (depends on 1) The display of claim 1, wherein the photoluminescence film layer is a single layer comprising a mixture of the green photoluminescence material and the red photoluminescence material incorporated in the light transmissive polymeric binder material. ### Claim 4 (depends on 1) The display of claim 1, wherein the photoluminescence film layer further comprises particles of a light scattering material incorporated in the light transmissive polymeric binder material. ### Claim 5 (depends on 1) The display of claim 1, wherein the wavelength converter film further comprises a light diffusive film layer comprising particles of a light scattering material, wherein the light diffusive film layer is fabricated directly on the photoluminescence film layer having no air gap between the layers or wherein the light diffusive film layer is fabricated separately and directly bonded to the photoluminescence film layer with a light transmissive material with no air gaps between the layers. ### Claim 6 (depends on 1) The display of claim 1, wherein the wavelength converter film further comprises a light transmissive protective film layer, wherein the light transmissive protective film layer is directly fabricated on the photoluminescence layer having no air gap between the layers or wherein the light transmissive protective film layer is fabricated separately and directly bonded to the photoluminescence film layer with a light transmissive material with no air gaps between the layers. ### Claim 7 (depends on 1) The display of claim 1, wherein the green photoluminescence material has a peak emission wavelength in a range from 530 nm to 545 nm. ### Claim 8 (depends on 1) The display of claim 1, wherein the red photoluminescence material has a peak emission wavelength in a range from 600 nm to 650 nm. ### Claim 9 (depends on 1) The display of claim 1, wherein the blue light has a dominant wavelength in a wavelength range 445 nm to 465 nm. ### Claim 10 (depends on 1) The display of claim 1, further comprising a brightness enhancement film positioned between the wavelength converter film and the display panel. ### Claim 11 (depends on 1) The display of claim 1, wherein the green photoluminescence material comprises phosphor material with a general composition (M)(A)2S4:Eu, wherein: M is at least one of Mg, Ca, Sr and Ba; and A is at least one of Ga, Al, In, Y. ### Claim 12 (depends on 1) The display of claim 1, wherein the red photoluminescence material comprises phosphor material with composition represented by the chemical formula MSe1-xSx:Eu, wherein M is at least one of Mg, Ca, Sr, Ba and Zn and 0