# US 11,994,709 B2 · Optical member, and backlight unit and image display device using said optical member > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,994,709 B2 - Document ID: US11994709B2 - Status: Granted - Kind: B2 - Application number: 17/914,043 - Filed: 2021-03-25 - Published: 2023-05-18 - Granted: 2024-05-28 - Earliest claimed: 2020-03-26 - Assignees: Nitto Denko Corporation - Applicants: Nitto Denko Corporation - Inventors: Takahiro Yoshikawa; Daisuke Hattori; Ryota Morishima; Atsushi Kishi - Web page: https://patentgrep.com/patent/US11994709B2 ## CPC - G02B 6/0055: {Reflecting element, sheet or layer} - G02B 6/0065: {Manufacturing aspects; Material aspects} - G02B 1/14: Protective coatings, e.g. hard coatings - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract Provided is an optical member, which is suppressed from causing a reduction in display quality due to wear or a flaw resulting from its vibration while maintaining the excellent characteristics of its low-refractive index layer. The optical member includes: a light guide plate having an end surface that light from a light source enters and an emitting surface from which the entered light is emitted; and a reflective plate bonded to a side of the light guide plate opposite to the emitting surface via a double-sided pressure-sensitive adhesive film. The double-sided pressure-sensitive adhesive film includes a first pressure-sensitive adhesive layer, a low-refractive index layer, and a second pressure-sensitive adhesive layer from the light guide plate side. The optical member further includes a surface-treated layer formed on a side of the reflective plate opposite to the double-sided pressure-sensitive adhesive film. ## Claims ### Claim 1 An optical member, comprising: a light guide plate having an end surface that light from a light source enters and an emitting surface from which the entered light is emitted; and a reflective plate bonded to a side of the light guide plate opposite to the emitting surface via a double-sided pressure-sensitive adhesive film, wherein the double-sided pressure-sensitive adhesive film includes a first pressure-sensitive adhesive layer, a low-refractive index layer, and a second pressure-sensitive adhesive layer from a light guide plate side, wherein the optical member further comprises a surface-treated layer formed on a side of the reflective plate opposite to the double-sided pressure-sensitive adhesive film, and the first pressure-sensitive adhesive layer has a storage modulus of elasticity of 1.2×105 (Pa) or more and the second pressure-sensitive adhesive layer has a storage modulus of elasticity of 9.0×104 (Pa) or less. ### Claim 2 (depends on 1) The optical member according to claim 1, wherein the surface-treated layer has a dynamic friction coefficient of 1.0 or less. ### Claim 3 (depends on 1) The optical member according to claim 1, wherein the surface-treated layer is a hard coat layer having a pencil hardness of H or more. ### Claim 4 (depends on 3) The optical member according to claim 3, wherein the surface-treated layer further includes an outermost layer containing fluorine on a surface of the hard coat layer opposite to the reflective plate. ### Claim 5 (depends on 1) A backlight unit, comprising: the optical member of claim 1; and a light source, wherein the light source is arranged so as to face the end surface of the light guide plate. ### Claim 6 (depends on 5) An image display apparatus, comprising: the backlight unit of claim 5; and an image display panel arranged on an emitting surface side of the light guide plate. ### Claim 7 (depends on 1) The backlight unit according to claim 1, wherein the low-refractive index layer has pores therein and the porosity of the low-refractive index layer is 40% or more and 85% or less. ### Claim 8 (depends on 1) The backlight unit according to claim 1, wherein a size of each of the pores in the low-refractive index layer is from 2 nm to 500 nm. ### Claim 9 (depends on 1) The backlight unit according to claim 1, wherein the low-refractive index layer has a refractive index of 1.30 or less. ### Claim 10 (depends on 1) The backlight unit according to claim 1, wherein the low-refractive index layer has a haze of less than 5%. ### Claim 11 (depends on 1) The backlight unit according to claim 1, wherein the low-refractive index layer has a thickness of from 0.2 μm to 5μm. ### Claim 12 (depends on 1) The backlight unit according to claim 1, wherein the low-refractive index layer is formed of one or a plurality of kinds of constituent units each forming a fine pore structure, and the constituent units are chemically bonded to each other through a catalytic action. ### Claim 13 (depends on 1) The backlight unit according to claim 1, wherein the first pressure-sensitive adhesive layer is adjacent to the low-refractive index layer and has a storage modulus of elasticity of from 1.3×105 (Pa) to 1.0×106 (Pa). ### Claim 14 (depends on 1) The backlight unit according to claim 1, wherein the second pressure-sensitive adhesive layer has a storage modulus of elasticity of from 5.0×103 (Pa) to 9.0×104 (Pa). ### Claim 15 An optical member, comprising: a light guide plate having an end surface that light from a light source enters and an emitting surface from which the entered light is emitted; and a reflective plate bonded to a side of the light guide plate opposite to the emitting surface via a double-sided pressure-sensitive adhesive film, wherein the double-sided pressure-sensitive adhesive film includes a first pressure-sensitive adhesive layer, a low-refractive index layer, and a second pressure-sensitive adhesive layer from a light guide plate side, wherein the optical member further comprises a surface-treated layer formed on a side of the reflective plate opposite to the double-sided pressure-sensitive adhesive film, wherein the surface-treated layer has a dynamic friction coefficient of 1.0 or less, wherein the low-refractive index layer is formed of one or a plurality of kinds of constituent units each forming a fine pore structure, and the constituent units are chemically bonded to each other through a catalytic action, wherein the low-refractive index layer has pores therein and the porosity of the low-refractive index layer is 40% or more and 85% or less, wherein a size of each of the pores in the low-refractive index layer is from 2 nm to 500 nm, wherein the low-refractive index layer has a refractive index of 1.30 or less, has a haze of less than 5%, and has a thickness of from 0.2 μm to 5 μm, wherein the first pressure-sensitive adhesive layer is adjacent to the low-refractive index layer and has a storage modulus of elasticity of from 1.3×105 (Pa) to 1.0×106 (Pa), and wherein the second pressure-sensitive adhesive layer has a storage modulus of elasticity of from 5.0×103 (Pa) to 9.0×104 (Pa).