# US 11,112,559 B2 · Method of fabricating light guide plate, light guide plate fabricated thereby, and illumination device having the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,112,559 B2 - Document ID: US11112559B2 - Status: Granted - Kind: B2 - Application number: 16/374,381 - Filed: 2019-04-03 - Published: 2020-04-02 - Granted: 2021-09-07 - Earliest claimed: 2018-10-01 - Assignees: Corning Incorporated - Applicants: Corning Incorporated - Inventors: Euisoo Kim; Seong-ryong Ryoo; Gun-sang Yoon - Web page: https://patentgrep.com/patent/US11112559B2 ## CPC - G02B 6/0088: {of the light guide or other optical sheets in the package} - G02B 6/0031: {Reflecting element, sheet or layer} - G02B 6/0043: {provided on the surface of the light guide} - G02B 6/0046: {Tapered light guide, e.g. wedge-shaped light guide} - G02B 6/0051: {Diffusing sheet or layer} - G02B 6/0055: {Reflecting element, sheet or layer} - G02B 6/0061: {to provide homogeneous light output intensity} - G02B 6/0065: {Manufacturing aspects; Material aspects} - G02B 6/0073: {Light emitting diode [LED]} - G02B 6/009: {of the light source in the package (G02B6/0021 takes precedence)} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A method of fabricating a light guide plate (LGP), an LGP fabricated thereby, and an illumination device having the same. The method includes preparing an LGP and fabricating a light-scattering layer by printing a printing solution including light-scattering particles on an overall bottom surface of the LGP. The light-scattering layer may be fabricated by at least one of a first method of controlling the printing such that the density of the light-scattering particles gradually increases with increases in a distance from the light-emitting diode facing a side surface of the LGP and a second method of controlling the printing such that the thickness of the light-scattering layer gradually increases with increases in the distance from the light-emitting diode. A luminous point through can be prevented from being viewed by a front observer, a process can be simplified, and light distribution similar to Lambertian distribution can be obtained. ## Claims ### Claim 1 A transparent light guide plate comprising: a light guide plate body comprising a first surface facing a front observer and through which light is irradiated, a second surface opposite to the first surface, and a third surface connected to a peripheral portion of the first surface and a peripheral portion of the second surface to connect the first surface and the second surface, the third surface facing a light-emitting diode; and a light-scattering layer fabricated on an overall area of the second surface, the light-scattering layer comprising a matrix layer and a number of light-scattering particles dispersed in the matrix layer wherein the light-scattering particles have a different refractive index than the matrix layer, wherein number of the light-scattering particles per unit area vary by at least 1.2 times from a position located adjacent to the light-emitting diode and a position farthest from the light-emitting diode, wherein a dispersion density of the number of light scattering particles and a thickness of the light-scattering layer gradually increase with increases in a distance from the light-emitting diode facing at least one surface of the third surface, wherein the light guide plate has a hazing value of 30% or less and a transmittance of 50% or more, wherein a surface roughness of the light-scattering layer is 100 nm or less. ### Claim 2 (depends on 1) The light guide plate of claim 1, wherein thicknesses of the light-scattering layer range from 1 μm to 5 μm. ### Claim 3 (depends on 1) The light guide plate of claim 1, wherein the light-scattering particles are formed from a material having a higher refractive index than that of the matrix layer. ### Claim 4 (depends on 3) The light guide plate of claim 3, wherein the light-scattering particles comprise at least one selected from among TiO2, ZrO2, BaTiO3, and SnO2. ### Claim 5 (depends on 1) An illumination device comprising: the light guide plate as claimed in claim 1; at least one light-emitting diode disposed to face at least one surface of the third surface defined as a side surface of the light guide plate; and a frame providing a space in which the light guide plate and the light-emitting diode are disposed. ### Claim 6 (depends on 5) The illumination device of claim 5, wherein, when the light-emitting diode is on, light is irradiated through the first surface defined as a front surface of the light guide plate and the second surface defined as a rear surface of the light guide plate, and when the light-emitting diode is off, the front observer facing the first surface is able to observe the second surface through the light guide plate. ### Claim 7 (depends on 5) The illumination device of claim 5, further comprising a reflector disposed adjacent to the second surface defined as a rear surface of the light guide plate. ### Claim 8 (depends on 1) The light guide plate of claim 1, wherein the light-scattering particles are applied in a printing solution at a range of from 0.1% to 5% by weight. ### Claim 9 (depends on 1) The light guide plate of claim 1, wherein numbers of the light-scattering particles dispersed within a portion of the light-scattering layer located adjacent to the light-emitting diode is about 30% to about 50% of a printing density while the light-scattering particles dispersed within a portion of the light-scattering layer farthest from the light-emitting diode is about 60% to about 80% of the printing density. ### Claim 10 (depends on 1) The light guide plate of claim 1, wherein numbers of the light-scattering particles dispersed within a portion of the light-scattering layer located adjacent to the light-emitting diode is greater than or equal to about 50% of a printing density while the light-scattering particles dispersed within a portion of the light-scattering layer farthest from the light-emitting diode is greater than or equal to about 80% of the printing density. ### Claim 11 (depends on 1) The light guide plate of claim 1, wherein light distribution out of the light guide plate is a Lambertian distribution. ### Claim 12 A transparent light guide plate comprising: a light guide plate body comprising a first surface facing a front observer and through which light is irradiated, a second surface opposite to the first surface, and a third surface connected to a peripheral portion of the first surface and a peripheral portion of the second surface to connect the first surface and the second surface, the third surface facing a light-emitting diode; and a light-scattering layer fabricated on an overall area of the second surface, the light-scattering layer comprising a matrix layer and a number of light-scattering particles dispersed in the matrix layer wherein the light-scattering particles have a different refractive index than the matrix layer, wherein a dispersion density of the number of light-scattering particles and a thickness of the light-scattering layer gradually increase with increases in a distance from the light-emitting diode facing at least one surface of the third surface, wherein the thickness of the light-scattering layer increases in a Gaussian distribution, wherein the light guide plate has a hazing value of 30% or less and a transmittance of 50% or more, wherein a surface roughness of the light-scattering layer is 100 nm or less. ### Claim 13 (depends on 12) The light guide plate of claim 12, wherein thicknesses of the light-scattering layer range from 1 μm to 5 μm. ### Claim 14 (depends on 12) The light guide plate of claim 12, wherein the light-scattering particles are formed from a material having a higher refractive index than that of the matrix layer. ### Claim 15 (depends on 14) The light guide plate of claim 14, wherein the light-scattering particles comprise at least one selected from among TiO2, ZrO2, BaTiO3, and SnO2. ### Claim 16 (depends on 12) An illumination device comprising: the light guide plate as claimed in claim 12; at least one light-emitting diode disposed to face at least one surface of the third surface defined as a side surface of the light guide plate; and a frame providing a space in which the light guide plate and the light-emitting diode are disposed. ### Claim 17 (depends on 16) The illumination device of claim 16, wherein, when the light-emitting diode is on, light is irradiated through the first surface defined as a front surface of the light guide plate and the second surface defined as a rear surface of the light guide plate, and when the light-emitting diode is off, the front observer facing the first surface is able to observe the second surface through the light guide plate. ### Claim 18 (depends on 16) The illumination device of claim 16, further comprising a reflector disposed adjacent to the second surface defined as a rear surface of the light guide plate. ### Claim 19 (depends on 12) The light guide plate of claim 12, wherein the light-scattering particles are applied in a printing solution at a range of from 0.1% to 5% by weight. ### Claim 20 (depends on 12) The light guide plate of claim 12, wherein light distribution out of the light guide plate is a Lambertian distribution.