# US 10,871,643 B2 · Display panel and display device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,871,643 B2 - Document ID: US10871643B2 - Status: Granted - Kind: B2 - Application number: 16/025,157 - Filed: 2018-07-02 - Published: 2019-07-04 - Granted: 2020-12-22 - Earliest claimed: 2018-01-03 - Assignees: Boe Technology Group Co., Ltd. - Applicants: Boe Technology Group Co., Ltd. - Inventors: Jifeng Tan - Web page: https://patentgrep.com/patent/US10871643B2 ## CPC - G02B 26/005: {based on electrowetting} - G02B 6/005: {provided by one optical element, or plurality thereof, placed on the light output side of the light guide} - G02B 6/0066: {characterised by the light source being coupled to the light guide} - G02B 2207/115: Electrowetting - G09G 3/2003: {Display of colours (specific for liquid crystal displays G09G3/3607)} - G09G 3/348: {based on the deformation of a fluid drop, e.g. electrowetting} - G09G 2300/0443: with several sub-pixels for the same colour in a pixel, not specifically used to display gradations (G09G3/364 takes precedence) - G09G 2320/0242: Compensation of deficiencies in the appearance of colours - G09G 2320/0666: for control of colour parameters, e.g. colour temperature - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A display panel includes: a first substrate; a second substrate disposed opposite to the first substrate; a waveguide layer disposed on a surface of the first substrate facing the second substrate for coupling incident light into the waveguide layer; a first electrode layer disposed on the waveguide layer, the first electrode layer including a plurality of independently controllable first electrodes; a second electrode layer disposed on a surface of the first substrate facing the second substrate; and a light emission control layer disposed between the first and the second electrode layers, the light emission control layer defining a plurality of sub-pixels arranged in an array. The light emission control layer controls respective amounts of light to be coupled out of the waveguide layer to respective ones of the plurality of sub-pixels based on respective voltages applied between the plurality of first electrodes and the second electrode layer. ## Claims ### Claim 1 A display panel comprising: a first substrate; a second substrate disposed opposite to the first substrate; a waveguide layer disposed on a surface of the first substrate facing the second substrate such that incident light is coupled into the waveguide layer; a first electrode layer disposed on the waveguide layer, wherein the first electrode layer comprises a plurality of first electrodes that are independently controllable; a second electrode layer disposed on a surface of the second substrate facing the first substrate; and a light emission control layer disposed between the first electrode layer and the second electrode layer, wherein the light emission control layer defines a plurality of sub-pixels arranged in an array, wherein the light emission control layer is configured to control respective amounts of light to be coupled out of the waveguide layer to respective ones of the plurality of sub-pixels based on respective voltages applied between the plurality of first electrodes and the second electrode layer, wherein the light emission control layer comprises: an insulating layer on a surface of the first electrode layer facing the second substrate; an oily medium between the insulating layer and the second electrode layer, the oily medium being distributed in the plurality of sub-pixels; and an aqueous medium between the insulating layer and the second electrode layer, the aqueous medium being distributed in the plurality of sub-pixels, wherein the light emission control layer further comprises a grating layer disposed on a surface of the insulating layer facing the second substrate, and wherein the grating layer comprises gaps formed periodically to allow the oily medium and the aqueous medium to be in contact with the insulating layer. ### Claim 2 (depends on 1) The display panel of claim 1, wherein the insulating layer comprises a hydrophobic insulating material, wherein the oily medium comprises a conductive medium, wherein the aqueous medium comprises an insulating medium, and wherein the oily medium is configured to change contact angles of the oily medium on the insulating layer in the different sub-pixels based on the respective voltages applied between the plurality of first electrodes and the second electrode layer, thereby changing the respective amounts of light coupled out of the waveguide layer to the respective sub-pixels. ### Claim 3 (depends on 1) The display panel of claim 1, wherein the insulating layer comprises at least one of a hydrophobic insulating material or a lipophilic insulating material, wherein in an initial state where the respective voltages are not applied the gaps of the grating layer are filled with the oily medium and the oily medium has a thickness greater than a height of the grating layer. ### Claim 4 (depends on 3) The display panel of claim 3, wherein the grating layer has a refractive index greater than or equal to a refractive index of the aqueous medium and less than a refractive index of the oil medium. ### Claim 5 (depends on 1) The display panel of claim 1, wherein the oily medium comprises red ink, green ink, and blue ink that are each respectively distributed in different ones of the plurality of sub-pixels. ### Claim 6 (depends on 1) The display panel of claim 1, wherein the grating layer has a same grating period in each of the plurality of sub-pixels. ### Claim 7 (depends on 1) The display panel of claim 1, wherein the insulating layer comprises an aqueous insulating material, wherein the oily medium comprises an insulating medium, wherein the aqueous medium comprises a conductive medium, and wherein the aqueous medium is configured to change respective contact angles of the aqueous medium on the insulating layer in the respective sub-pixels based on the respective voltages applied between the plurality of first electrodes and the second electrode layer, thereby changing the respective amounts of light coupled out of the waveguide layer to the respective sub-pixels. ### Claim 8 (depends on 1) The display panel of claim 1, wherein the insulating layer comprises an oleophobic insulating material, wherein the oily medium comprises an insulating medium, wherein the aqueous medium comprises a conductive medium, and wherein the aqueous medium is configured to change respective contact angles of the aqueous medium on the insulating layer in the respective sub-pixels based on the respective voltages applied between the plurality of first electrodes and the second electrode layer, thereby changing the respective amounts of light coupled out of the waveguide layer to the respective sub-pixels. ### Claim 9 (depends on 1) The display panel of claim 1, wherein the insulating layer comprises a lipophilic insulating material, wherein the oily medium comprises a conductive medium, wherein the aqueous medium comprises an insulating medium, and wherein the oily medium is configured to change respective contact angles of the oily medium on the insulating layer in the respective sub-pixels based on the respective voltages applied between the plurality of first electrodes and the second electrode layer, thereby changing the respective amounts of light coupled out of the waveguide layer to the respective sub-pixels. ### Claim 10 (depends on 1) The display panel of claim 1, wherein the oily medium comprises red ink, green ink, and blue ink that are respectively distributed in different ones of the plurality of sub-pixels. ### Claim 11 (depends on 1) The display panel of claim 1, wherein the oily medium comprises black ink distributed in each of the plurality of sub-pixels. ### Claim 12 (depends on 1) The display panel of claim 1, wherein the light emission control layer comprises a plurality of barrier walls intersecting each other to define the plurality of sub-pixels. ### Claim 13 A display device comprising: a display panel comprising: a first substrate; a second substrate disposed opposite to the first substrate; a waveguide layer disposed on a surface of the first substrate facing the second substrate for coupling incident light into the waveguide layer; a first electrode layer disposed on the waveguide layer, the first electrode layer comprising a plurality of first electrodes that are independently controllable; a second electrode layer disposed on a surface of the second substrate facing the first substrate; and a light emission control layer disposed between the first electrode layer and the second electrode layer, the light emission control layer defining a plurality of sub-pixels arranged in an array, wherein the light emission control layer is configured to control respective amounts of light to be coupled out of the waveguide layer to respective ones of the plurality of sub-pixels based on respective voltages applied between the plurality of first electrodes and the second electrode layer, wherein the light emission control layer comprises: an insulating layer on a surface of the first electrode layer facing the second substrate; an oily medium between the insulating layer and the second electrode layer, the oily medium being distributed in the plurality of sub-pixels; and an aqueous medium between the insulating layer and the second electrode layer, the aqueous medium being distributed in the plurality of sub-pixels, wherein the light emission control layer further comprises a grating layer disposed on a surface of the insulating layer facing the second substrate, and wherein the grating layer comprises gaps formed periodically to allow the oily medium and the aqueous medium to be in contact with the insulating layer. ### Claim 14 (depends on 13) The display device of claim 13, wherein the insulating layer comprises at least one of a hydrophobic insulating material or a lipophilic insulating material, wherein in an initial state where the respective voltages are not applied the gaps of the grating layer are filled with the oily medium and the oily medium has a thickness greater than a height of the grating layer. ### Claim 15 (depends on 14) The display device of claim 14, wherein the grating layer has a refractive index greater than or equal to a refractive index of the aqueous medium and less than a refractive index of the oil medium. ### Claim 16 (depends on 13) The display device of claim 13, further comprising an edge-lit collimated backlight for providing the incident light to be coupled into the waveguide layer.