# US 10,120,120 B2 · Reflective display apparatus and front light module thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,120,120 B2 - Document ID: US10120120B2 - Status: Granted - Kind: B2 - Application number: 15/073,671 - Filed: 2016-03-18 - Published: 2017-04-13 - Granted: 2018-11-06 - Earliest claimed: 2015-10-13 - Assignees: E Ink Holdings Inc. - Applicants: E Ink Holdings Inc. - Inventors: Yu-Nan Pao - Web page: https://patentgrep.com/patent/US10120120B2 ## CPC - G02B 6/0063: {for extracting light out both the major surfaces of the light guide} - G02B 6/0036: {2-D arrangement of prisms, protrusions, indentations or roughened surfaces} - G02B 6/005: {provided by one optical element, or plurality thereof, placed on the light output side of the light guide} - G02B 6/0053: {Prismatic sheet or layer; Brightness enhancement element, sheet or layer} - G02B 6/0061: {to provide homogeneous light output intensity} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A front light module includes a light guide plate, a light source and a light redirection film. The light guide plate includes a light incident surface, an inner light outgoing surface and an outer light outgoing surface. The light incident surface is adjoined between the inner light outgoing surface and the outer light outgoing surface. The light source is configured to emit light into the light incident surface of the light guide plate. The light redirection film is located beside the inner light outgoing surface, and is configured to redirect a traveling direction of the light from the light guide plate. An acute included angle between the light after redirected and a normal line of the inner light outgoing surface is less than an acute included angle between the light before redirected and the normal line of the inner light outgoing surface. ## Claims ### Claim 1 A front light module, comprising: a light guide plate comprising a light incident surface, an inner light outgoing surface and an outer light outgoing surface, the light incident surface being adjoined between the inner light outgoing surface and the outer light outgoing surface; a light source configured to emit light into the light incident surface of the light guide plate; and a light redirection film located beside the inner light outgoing surface, and configured to redirect a traveling direction of the light from the light guide plate, wherein an acute included angle between the light after redirected and a normal line of the inner light outgoing surface is less than an acute included angle between the light before redirected and the normal line of the inner light outgoing surface, the light redirection film comprising a light transmissive film body and a plurality of light redirection microstructures protruding from the light transmissive film body, wherein the light redirection microstructures are between the light transmissive film body and the light guide plate, wherein at least one of the light redirection microstructures comprises a first surface, and wherein the first surface and the inner light outgoing surface define an acute included angle therebetween, the acute included angle ranges from 30 degrees to 50 degrees. ### Claim 2 (depends on 1) The front light module of claim 1, wherein the light redirection microstructures are adjacent to the light guide plate; the light transmissive film body comprises a rear surface facing away from the light redirection microstructures; at least one of the light redirection microstructures comprises a first surface; and a perpendicular distance from the first surface to the rear surface decreases along a direction away from the light source. ### Claim 3 (depends on 2) The front light module of claim 2, wherein the light redirection microstructure comprises the first surface further comprises a second surface, wherein the second surface is adjacent to the first surface, and the second surface is closer to the light source than the first surface is; and a perpendicular distance from the second surface to the rear surface increases along a direction away from the light source. ### Claim 4 (depends on 3) The front light module of claim 3, wherein the second surface and the inner light outgoing surface define an acute included angle therebetween, and the acute included angle is greater than or equal to 70 degrees. ### Claim 5 (depends on 2) The front light module of claim 2, wherein the light redirection microstructure comprises the first surface further comprises a second surface that is adjacent to the first surface, wherein the second surface is closer to the light source than the first surface is; and the second surface is substantially perpendicular to the inner light outgoing surface. ### Claim 6 (depends on 2) The front light module of claim 2, further comprising a light transmissive adhesive layer at least adhered between the first surfaces of the light redirection microstructures and the inner light outgoing surface of the light guide plate. ### Claim 7 (depends on 6) The front light module of claim 6, wherein a refractive index of a material of the light transmissive adhesive layer is less than a refractive index of a material of the light redirection microstructures. ### Claim 8 (depends on 1) The front light module of claim 1, wherein the light guide plate comprises a plurality of light outgoing microstructures disposed on the inner light outgoing surface. ### Claim 9 (depends on 8) The front light module of claim 8, wherein the farther the light outgoing microstructures are located from the light source, the closer the light outgoing microstructures are arranged. ### Claim 10 (depends on 9) The front light module of claim 9, wherein the light redirection microstructures are adjacent to the light outgoing microstructures of the light guide plate; and the light redirection microstructures are uniformly arranged. ### Claim 11 A reflective display apparatus, comprising: a light guide plate comprising a light incident surface and an inner light outgoing surface, the light incident surface being adjoined to the inner light outgoing surface; a light source configured to emit light into the light incident surface of the light guide plate; a reflective display panel comprising a display surface toward the inner light outgoing surface of the light guide plate; and a light redirection film located between the display surface of the reflective display panel and the inner light outgoing surface of the light guide plate, and the light redirection film configured to redirect a traveling direction of the light from the light guide plate toward the display surface, wherein an acute included angle between the light after redirected and a normal line of the display surface is less than an acute included angle between the light before redirected and the normal line of the display surface, wherein the light redirection film comprises a light transmissive film body and a plurality of light redirection microstructures disposed on the light transmissive film body, wherein at least one of the light redirection microstructures comprises a first surface, and a perpendicular distance from the first surface to the display surface decreases along a direction away from the light source. ### Claim 12 (depends on 11) The reflective display apparatus of claim 11, wherein the light redirection microstructures and the reflective display panel are respectively located on opposite sides of the light transmissive film body. ### Claim 13 (depends on 12) The reflective display apparatus of claim 12, wherein the first surface and the display surface define an acute included angle therebetween, and the acute included angle ranges from 30 degrees to 50 degrees. ### Claim 14 (depends on 12) The reflective display apparatus of claim 12, wherein the light redirection microstructure comprising the first surface further comprises a second surface that is adjacent to the first surface and is closer to the light source than the first surface is, wherein a perpendicular distance from the second surface to the display surface increases along a direction away from the light source. ### Claim 15 (depends on 14) The reflective display apparatus of claim 14, wherein the second surface and the display surface define an acute included angle therebetween, and the acute included angle is greater than or equal to 70 degrees. ### Claim 16 (depends on 12) The reflective display apparatus of claim 12, wherein the light redirection microstructure comprising the first surface further comprises a second surface that is adjacent to the first surface, wherein the second surface is closer to the light source than the first surface is, and is substantially perpendicular to the display surface. ### Claim 17 (depends on 12) The reflective display apparatus of claim 12, wherein the first surface of the light redirection microstructure is formed in a planar shape, a convex shape, a concave shape, a jagged shape, a wavy shape or combinations thereof. ### Claim 18 (depends on 11) The reflective display apparatus of claim 11, wherein the reflective display panel comprises a color filter therein, and the color filter comprises a plurality of light filter zones, wherein the respective light filter zones have different permissible wavelength ranges. ### Claim 19 (depends on 11) The reflective display apparatus of claim 11, further comprising a light transmissive adhesive layer adhered between the light redirection film and the display surface of the reflective display panel.