WO2023204962A1 - Rétroéclairages comprenant des diffuseurs en verre à motif et procédés de fabrication des rétroéclairages - Google Patents

Rétroéclairages comprenant des diffuseurs en verre à motif et procédés de fabrication des rétroéclairages Download PDF

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Publication number
WO2023204962A1
WO2023204962A1 PCT/US2023/017247 US2023017247W WO2023204962A1 WO 2023204962 A1 WO2023204962 A1 WO 2023204962A1 US 2023017247 W US2023017247 W US 2023017247W WO 2023204962 A1 WO2023204962 A1 WO 2023204962A1
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WO
WIPO (PCT)
Prior art keywords
glass substrate
adhesive
diffuser
backlight
layer
Prior art date
Application number
PCT/US2023/017247
Other languages
English (en)
Inventor
Joon-Soo Kim
Dmitri Vladislavovich Kuksenkov
Young Suk Lee
Hyung Soo Moon
Timothy James Orsley
Seung-Yong Park
Original Assignee
Corning Incorporated
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Corning Incorporated filed Critical Corning Incorporated
Publication of WO2023204962A1 publication Critical patent/WO2023204962A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • 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
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G—PHYSICS
    • G02—OPTICS
    • 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
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133603—Direct backlight with LEDs

Definitions

  • the present disclosure relates generally to backlights for displays. More particularly, it relates to backlights including patterned glass diffusers that support the light sources.
  • LCDs are commonly used in various electronics, such as cell phones, laptops, electronic tablets, televisions, and computer monitors.
  • LCDs are light valve-based displays in which the display panel includes an array of individually addressable light valves.
  • LCDs may include a backlight for producing light that may then be wavelength converted, filtered, and/or polarized to produce an image from the LCD.
  • Backlights may be edge-lit or direct-lit.
  • Edge-lit backlights may include a light emitting diode (LED) array edge- coupled to a light guide plate that emits light from its surface.
  • Direct-lit backlights may include a two-dimensional (2D) array of LEDs directly behind the LCD panel.
  • Direct-lit backlights may have the advantage of improved dynamic contrast as compared to edge-lit backlights.
  • a display with a direct-lit backlight may independently adjust the brightness of each LED to set the dynamic range of the brightness across the image. This is commonly known as local dimming.
  • a diffuser plate or film may be positioned at a distance from the LEDs, thus making the overall display thickness greater than that of an edge-lit backlight. Lenses positioned over the LEDs have been used to improve the lateral spread of light in direct-lit backlights.
  • optical distance (OD) for light traveling between the LEDs and the diffuser plate or film in such configurations e.g., from at least 10 to typically about 20-30 millimeters
  • OD optical distance
  • edge-lit backlights may be thinner, the light from each LED may spread across a large region of the light guide plate such that turning off individual LEDs or groups of LEDs may have only a minimal impact on the dynamic contrast ratio.
  • the backlight includes a patterned glass diffuser, a redistribution layer, a plurality of light sources, and an adhesive .
  • the patterned glass diffuser includes a glass substrate and a variable diffuser pattern on a first surface of the glass substrate.
  • the plurality of light sources is electrically coupled to the redistribution layer and proximate a second surface of the glass substrate opposite the first surface.
  • the adhesive is between the redistribution layer and the patterned glass diffuser.
  • the backlight includes a patterned glass diffuser, a redistribution layer, a plurality of light sources, a solder resist layer, and an adhesive.
  • the plurality of light sources is electrically coupled to the redistribution layer and proximate the patterned glass diffuser.
  • the solder resist layer is proximate the redistribution layer.
  • the adhesive is between the solder resist layer and the patterned glass diffuser.
  • Yet other embodiments of the present disclosure relate to a method for fabricating a backlight.
  • the method includes applying a release layer to a first glass substrate, and forming a redistribution layer on the release layer.
  • the method includes electrically coupling a plurality of light sources to the redistribution layer, and applying an adhesive over the redistribution layer and the plurality of light sources.
  • the method includes attaching a second glass substrate to the adhesive, and removing the first glass substrate from the redistribution layer.
  • the backlight fabrication methods disclosed herein are compatible with conventional light emitting diode (LED) transfer and repair equipment.
  • the backlights may use conventional top emissive LED chips.
  • the glass circuit boards e.g., including a glass substrate, a redistribution layer, and LEDs
  • the glass circuit boards may be tested and repaired prior to integration with a patterned glass diffuser.
  • additional optical components for light distribution such as dome lenses, may be eliminated.
  • the disclosed backlights may have higher light emission efficiency due to optical bonding between the patterned glass diffuser and the LEDs.
  • the LEDs within the backlights may have an improved alignment with the variable diffuser pattern of the patterned glass diffuser since they are bonded to the patterned glass diffuser by the adhesive.
  • the variable diffuser pattern of the patterned glass diffuser may be fabricated (e.g., printed) after attaching the glass circuit board to the patterned glass diffuser substrate to precisely align the variable diffuser pattern relative to each individual LED.
  • the disclosed backlights Due to a single core substrate structure after removing the glass substrate of the glass circuit board, the disclosed backlights may have a thin form factor.
  • the disclosed backlights may have a narrow or zero bezel with a low CTE single core substrate structure.
  • Thermal management designs for the backlights may be improved due to a core-less circuit board structure (e.g., lift-off glass substrate). Backlights including full size LED circuit boards without tiling may be realized even for large size displays.
  • an external connection cable or an external driver integrated circuit (IC) board may be attached to the backlights after lifting off the glass substrate of the glass circuit board.
  • FIG. 1A is a simplified cross-sectional view of an exemplary backlight
  • FIG. IB is a top view of an exemplary backlight
  • FIGS. 1C-1J are simplified cross-sectional views of other exemplary backlights
  • FIGS. 2A-2G are simplified cross-sectional views of exemplary patterned glass diffuser fabrication steps
  • FIGS. 3A-3E are simplified cross-sectional views of exemplary glass circuit board fabrication steps
  • FIGS. 4A and 4B are simplified cross-sectional views of exemplary backlight fabrication steps
  • FIGS. 5A-5H are flow diagrams illustrating an exemplary method for fabricating a backlight; and [0018] FIG. 6 illustrates an exemplary multi-tile backlight fabrication process.
  • Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
  • LCDs liquid crystal displays
  • HDR high dynamic range
  • contrast ratio improved aesthetics, such as a narrow (or zero) bezel and thinner form factors.
  • 2D two-dimensional
  • mini-LEDs have drawn attention for 2D local dimmable direct-lit backlight applications, since mini-LEDs may enable a thinner form factor by reducing optical distance (OD), improve contrast by increasing the number of dimming zones, improve peak brightness for HDR, and enable narrow or zero bezel designs.
  • OD optical distance
  • Mini-LEDs adaptation in backlights may require new materials and stack designs. Due to the tiny size of mini-LEDs, surface mount technology (SMT) equipment needs high pattern accuracy and dimensional stability of the circuit board.
  • SMT surface mount technology
  • Conventional plastic based printed circuit boards (PCBs) may have already reached the limit of their pattern accuracy and dimensional stability for mini -LED backlight LCD displays. Glass or glass ceramic substrates including inherent flexural rigidity, a flat surface, and higher thermal dimensional stability may replace typical substrate materials such as FR-4.
  • Glass circuit boards (GCBs) may improve LED transfer yield and soldering reliability at larger sizes (e.g., larger than typical PCB sizes of about 400 by 500 millimeters), which may enable lower cost and more reliable backlights.
  • achieving a thinner form factor by reducing the optical distance is desirable.
  • the light generated from thousands of mini -LED chips should be distributed to produce a uniform illumination of the backlight, and the optical structure of the mini-LED backlight should occupy a limited vertical space.
  • a thinner form factor by reducing the OD may be achieved with a patterned light guide plate (LGP), which includes an engineered reflective and light extracting pattern on the surface.
  • a patterned glass diffuser (PGD) may greatly reduce the OD.
  • LEDs e.g., mini-LEDs
  • a GCB and a PGD are integrated to include a single glass substrate.
  • the backlights may be fabricated using conventional top emission LED chips using SMT and repair equipment.
  • the GCB delivers the electric current to the LEDs and the PGD is optically bonded to each LED to achieve a uniform brightness in a thin form factor.
  • both the GCB and the PGD include matching coefficients of thermal expansion (CTE)
  • the LEDs may be aligned with the pattern of the PGD so that optical performance is improved.
  • a single substrate structure may be realized after lifting off the glass substrate from the GCB, resulting in an extremely thin form factor backlight.
  • Backlight 100a includes a redistribution layer 102, a plurality of light sources 108 (one light source is illustrated in FIG. 1A), an adhesive 120, and a patterned glass or other suitable material (e.g., plastic) diffuser 122.
  • the patterned diffuser 122 may include a glass substrate 128 and a variable diffuser pattern 130 on a first surface 124 of the glass substrate.
  • the patterned diffuser 122 may include a plastic (e.g., PMMA) substrate 128 and a variable diffuser pattern 130 on a first surface 124 of the plastic substrate.
  • the plurality of light sources 108 are electrically coupled to the redistribution layer 102 and proximate a second surface 126 of the substrate 128 opposite to the first surface 124.
  • Redistribution layer 102 includes electrically conductive material (e.g., metal, such as copper) traces 104 separated by a dielectric material (e.g., resin) 106.
  • Each light source 108 includes a first contact 110a and a second contact 110b electrically coupled to the redistribution layer 102 via an electrically conductive material (e.g., solder) 112.
  • each light source 108 may include atop emission light emitting diode (e.g., miniLED).
  • the adhesive 120 is between the redistribution layer 102 and the patterned diffuser 122.
  • Adhesive 120 may include a reflective silicon adhesive or another suitable adhesive.
  • adhesive 120 may include a mixture of an organic base adhesive and reflective particles.
  • the optical properties of adhesive 120, such as reflectance, haze, and transmittance, as well as viscosity are variable depending upon the mix ratio of the reflective particles.
  • the thickness of the adhesive 120 may be sufficient to cover the plurality of light sources 108. In addition, the thickness of the adhesive 120 may set the distance between the patterned diffuser 122 and the redistribution layer 102.
  • the substrate 128 may include any suitable transparent glass material used for lighting and display applications.
  • the term “transparent” is intended to denote that the substrate has an optical transmission of greater than about 70 percent over a length of 500 millimeters in the visible region of the spectrum (about 420-750 nanometers).
  • an exemplary transparent glass material may have an optical transmittance of greater than about 50 percent in the ultraviolet (UV) region (about 100-400 nanometers) over a length of 500 millimeters.
  • the substrate may include an optical transmittance of at least 95 percent over a path length of 50 millimeters for wavelengths ranging from about 450 nanometers to about 650 nanometers.
  • the optical properties of the substrate may be affected by the refractive index of the transparent glass material.
  • the substrate 128 may have a refractive index ranging from about 1.3 to about 1.8.
  • the substrate 128 may have a relatively low level of light attenuation (e.g., due to absorption and/or scattering).
  • the light attenuation (a) of the substrate 128 may, for example, be less than about 5 decibels per meter for wavelengths ranging from about 420-750 nanometers.
  • the substrate 128 may include aluminosilicate, alkali-aluminosilicate, borosilicate, alkali-borosilicate, aluminoboro silicate, alkali-aluminoborosilicate, soda lime, or other suitable glasses.
  • suitable glasses suitable for use as a glass substrate 128 include EAGLE XG®, LotusTM, Willow®, IrisTM, and Gorilla® glasses from Coming Incorporated.
  • the substrate 128 may have a relatively high level of light attenuation.
  • the light attenuation (a) of the substrate 128 may, for example, be greater than about 5 decibels per meter for wavelengths ranging from about 420-750 nanometers.
  • Variable diffuser pattern 130 distributes the light from the plurality of light sources 108 for uniform illumination of the backlight 100a within the substrate 128.
  • the variable diffuser pattern 130 may achieve uniform light distribution by reducing light density in areas close to each light source 108 (e.g., directly above each light source 108) and extracting light in other areas (e.g., between light sources 108).
  • the variable diffuser pattern 130 may include an organic base transparent material (cured by UV or thermal) plus reflective particles. While patterned diffuser 122 may be referred to herein as patterned glass diffuser 122, the embodiments are also applicable to a patterned plastic diffuser 122.
  • FIG. IB is atop view of the backlight 100a of FIG. 1A including the plurality of light sources 108 and the adhesive 120 on the redistribution layer 102.
  • Light sources 108 are arranged in a 2D array including a plurality of rows and a plurality of columns. While nine light sources 108 are illustrated in FIG. IB in three rows and three columns, in other embodiments backlight 100a may include any suitable number of light sources 108 arranged in any suitable number of rows and any suitable number of columns.
  • Light sources 108 may also be arranged in other periodic patterns, for example, a hexagonal or triangular lattice, or as quasi-periodic or non-strictly periodic patterns. For example, the spacing between light sources 108 may be smaller at the edges and/or comers of the backlight.
  • Redistribution layer 102 passes electrical signals to each light source 108 for individually controlling each light source.
  • Each of the plurality of light sources 108 may, for example, be an LED (e.g., size larger than about 0.5 millimeters), a mini-LED (e.g., size between about 0.1 millimeters and about 0.5 millimeters), amicro-LED (e.g., size smallerthan about 0.1 millimeter), an organic LED (OLED), or another suitable light source having a wavelength ranging from about 400 nanometers to about 750 nanometers.
  • each of the plurality of light sources 108 may have a wavelength shorter than 400 nanometers and/or longer than 750 nanometers.
  • each light source 108 is optically coupled to the patterned glass diffuser 128.
  • the term “optically coupled” is intended to denote that a light source is positioned proximate a surface of the patterned glass diffuser 122 and is in optical communication with the patterned glass diffuser 122 directly or through an adhesive, so as to introduce light into the patterned glass diffuser 122 that at least partially propagates due to total internal reflection.
  • each light source 108 is optically coupled to the patterned glass diffuser 122 such that a first portion of the light travels laterally in the substrate 128 due to the total internal reflection and is extracted out of the substrate 128 by the variable diffuser pattern 130, and a second portion of the light travels laterally between the adhesive 120 and the variable diffuser pattern 130 due to multiple reflections at the reflective surfaces of the adhesive 120 and the variable diffuser pattern 130 or between an optical film stack (not shown) above the backlight (e.g., for a LCD display) and the adhesive 120.
  • FIG. 1C is a simplified cross-sectional view of an exemplary backlight 100b.
  • Backlight 100b is similar to backlight 100a previously described and illustrated with reference to FIG. 1A.
  • the redistribution layer 102 forms a connector 142 (e.g., a flexible connector).
  • a release layer 140 is attached to the bottom surface of the redistribution layer 102.
  • the connector 142 may be electrically connected to a light source driving circuit to control each light source 108.
  • the release layer 140 may be used to enable lift-off of a substrate on which the redistribution layer 102 is formed as described in more detail below.
  • the release layer 140 may include 3M® LTHC (light-to-heat conversion coating) or another suitable material.
  • FIG. ID is a simplified cross-sectional view of an exemplary backlight 100c.
  • Backlight 100c is similar to backlight 100b previously described and illustrated with reference to FIG. 1C.
  • Backlight 100c also includes a uniform diffuser pattern 132 on the second surface 126 of the glass substrate 128.
  • the second surface 126 of the glass substrate 128 and the uniform diffuser pattern 132 face the plurality of light sources 108, and the first surface 124 of the glass substrate 128 and the variable diffuser pattern 130 face away from the plurality of light sources 108.
  • the second surface 126 of the glass substrate 128 and the uniform diffuser pattern 132 may face away from the plurality of light sources 108, and the first surface 124 of the glass substrate 128 and the variable diffuser pattern 130 may face the plurality of light sources 108.
  • the uniform diffuser pattern 132 may improve the light efficiency of backlight 100c compared to backlight 100b.
  • the uniform diffuser pattern 132 may include an organic base transparent material (cured by UV or thermal) plus reflective particles.
  • FIG. IE is a simplified cross-sectional view of an exemplary backlight lOOd.
  • Backlight lOOd is similar to backlight 100a previously described and illustrated with reference to FIG. 1 A.
  • the second surface 126 of the glass substrate 128 faces away from the plurality of light sources 108, and the first surface 124 of the glass substrate 128 and the variable diffuser pattern 130 face the plurality of light sources 108.
  • FIG. IF is a simplified cross-sectional view of an exemplary backlight 100c.
  • Backlight 100c is similar to backlight 100a previously described and illustrated with reference to FIG. 1A.
  • Backlight 100c also includes a uniform diffuser pattern 132 on the first surface 124 of the glass substrate 128.
  • the variable diffuser pattern 130 is formed on the uniform diffuser pattern 132, such that the uniform diffuser pattern 132 is between the glass substrate 128 and the variable diffuser pattern 130.
  • the uniform diffuser pattern 132 in combination with the variable diffuser pattern 130 may improve the light efficiency of backlight 100c compared to backlight 100a.
  • FIG. 1G is a simplified cross-sectional view of an exemplary backlight lOOf.
  • Backlight lOOf is similar to backlight 100a previously described and illustrated with reference to FIG. 1A.
  • Backlight lOOf includes a reflective adhesive layer 120 over the redistribution layer 102 and a scattering adhesive layer 150 over the reflective adhesive layer 120.
  • the scattering adhesive layer 150 contacts the second surface 126 of the glass substrate 128.
  • the reflective adhesive layer 120 may be dispensed onto redistribution layer 102 and cured. Next, the scattering adhesive layer 150 may be applied over the reflective adhesive layer 120.
  • the scattering adhesive layer 150 may include less reflective particle content than the reflective adhesive layer 120.
  • the reflective adhesive layer 120 in combination with the scattering adhesive layer 150 may improve the optical performance of backlight lOOf compared to backlight 100a.
  • FIG. 1H is a simplified cross-sectional view of an exemplary backlight 100g.
  • Backlight 100g is similar to backlight 100a previously described and illustrated with reference to FIG. 1A.
  • Backlight 100g includes a patterned reflective film 160 between the redistribution layer 102 and the patterned glass diffuser 122.
  • the patterned reflective film 160 contacts the second surface 126 of the glass substrate 128.
  • the patterned reflective film 160 includes a plurality of through-holes (one through-hole is illustrated in FIG. 1H) corresponding to the plurality of light sources 108.
  • Adhesive 120 fills the remaining space between the patterned reflective film 160, the patterned glass diffuser 122 and the redistribution layer 102.
  • adhesive 120 may be a transparent adhesive that also provides an optical bond between each light source 108 and the patterned glass diffuser 122.
  • the patterned reflective film 160 may act as a spacer between the patterned glass diffuser 122 and the redistribution layer 102. Therefore, the patterned reflective film 160 may have a thickness greater than the distance between the top of each light source 108 and the redistribution layer 102.
  • the patterned reflective film 160 may include an organic base transparent material (cured by UV or thermal) plus reflective particles.
  • FIG. II is a simplified cross-sectional view of an exemplary backlight lOOh.
  • Backlight lOOh is similar to backlight 100a previously described and illustrated with reference to FIG. 1A.
  • Backlight lOOh includes a solder resist layer 170 proximate (e.g., contacting) the redistribution layer 102.
  • solder resist layer 170 may include a reflective solder resist layer (e.g., a white solder resist layer).
  • Solder resist layer 170 surrounds each light source 108.
  • Adhesive 120 is between the solder resist layer 170 and the patterned glass diffuser 122.
  • adhesive 120 may be a transparent or clear adhesive including scattering particles that acts as a light path for light emitted from the sides of light sources 108 to improve light efficiency.
  • each light source 108 may be coated with a reflective layer on the top surface of the light source to minimize hot spots. In this case, with a reflective layer on the top surface of each light source 108, the adhesive 120 may enhance the optical performance of the backlight lOOh.
  • FIG. 1J is a simplified cross-sectional view of an exemplary backlight lOOi.
  • Backlight lOOi is similar to backlight 100b previously described and illustrated with reference to FIG. 1C.
  • Backlight lOOi includes a function layer 180 attached to the bottom surface of the redistribution layer 102.
  • the function layer 180 may be attached to the redistribution layer 102 via the release layer 140 or another suitable material, such as an adhesive material or solder.
  • the function layer 180 may include a heat sink or heat dissipation film for thermal management of the plurality of light sources 108, a protective film for downstream processes and/or for the completed backlight, a circuit board (e.g., for driver integrated circuits to drive the plurality of light sources 108), or another suitable layer.
  • FIGS. 2A-2G are simplified cross-sectional views of exemplary patterned glass diffuser fabrication steps.
  • FIG. 2A is a cross-sectional view of a glass substrate 128.
  • Glass substrate 128 may be sized based on the backlight size to be fabricated such that glass substrate 128 is not subject to cutting during the remainder of the fabrication process.
  • Glass substrate 128 includes a first surface 124 and a second surface 126 opposite to the first surface 124.
  • FIG. 2B is a cross-sectional view of the glass substrate 128 of FIG. 2A after forming a variable diffuser pattern 130 on the first surface 124 of the glass substrate 128.
  • the variable diffuser pattern 130 may be formed by printing (e.g., inkjet printing, screen printing), photolithography and etching processes, or other suitable processes. The process materials and conditions may be based on the resolution of the variable diffuser pattern 130, the desired reflectivity, scalability, etc.
  • FIG. 2C is a cross-sectional view of the glass substrate 128 and variable diffuser pattern 130 of FIG. 2B after forming a uniform diffuser pattern 132 on the second surface 126 of the glass substrate 128.
  • the uniform diffuser pattern 132 may be printed, laminated, or formed using another suitable process on the second surface 126 of the glass substrate 128.
  • FIG. 2D is a cross-sectional view of the glass substrate 128 of FIG. 2A after forming a uniform diffuser pattern 132 on the first surface 124 of the glass substrate 128 and a variable diffuser pattern 130 on the uniform diffuser pattern 132.
  • the uniform diffuser pattern 132 may be printed, laminated, or formed using another suitable process on the first surface 124 of the glass substrate 128.
  • the variable diffuser pattern 130 may then be formed on the uniform diffuser pattern 132 by printing (e.g., inkjet printing, screen printing), photolithography and etching processes, or other suitable processes. In other embodiments, the uniform diffuser pattern 132 and the variable diffuser pattern 130 may be formed simultaneously.
  • FIG. 2E is a cross-sectional view of the glass substrate 128 of FIG. 2B after applying a reflective film 160 to the second surface 126 of the glass substrate 128.
  • Reflective film 160 may include a photo sensitive film.
  • the photo sensitive film may be patterned using a photolithography process to define a pattern 162 corresponding to an arrangement of a plurality of light sources. Photolithography processes can form fine patterns with precise positioning, so light sources may be placed in alignment with the patterned glass diffuser without further aligning processes.
  • FIG. 2F is a cross-sectional view of the glass substrate 128 with reflective film 160 of FIG. 2E after removing the portions defined by the pattern 162 to form through-holes 164 through the reflective film 160.
  • the portions defined by the pattern 162 may be removed using an etching process if photolithography is used to define the pattern 162.
  • the portions defined by pattern 162 may be removed using a punching process prior to applying the reflective film to the glass substrate 128. While a punching process is cost effective, the punching process may form the patterned reflective film with less precision than a photolithography process.
  • FIG. 2G is a cross-sectional view of the glass substrate 128 with the patterned reflective film 160 of FIG. 2F after applying an adhesive 120 to exposed portions of the second surface 126 ofthe glass substrate 128 and the patterned reflective film 160.
  • the adhesive 120 may be a transparent or clear adhesive.
  • Light sources 108 may be inserted into respective through-holes 164 prior to curing of the adhesive.
  • FIGS. 3A-3E are simplified cross-sectional views of exemplary glass circuit board fabrication steps.
  • FIG. 3A is a cross-sectional view of a glass substrate 300.
  • substrate 300 may include a material other than glass.
  • Glass substrate 300 may be similar to glass substrate 128 previously described.
  • the glass substrate 300 may be sized based on the backlight size to be fabricated such that one glass substrate 300 is used to fabricate the backlight.
  • the glass substrate 300 may be sized such that multiple (e.g., 2, 3, 4, etc.) glass substrates 300 may be used to fabricate the backlight.
  • FIG. 3B is a cross-sectional view of the glass substrate 300 of FIG. 3A after applying a release layer 140 on the glass substrate 300.
  • the release layer 140 may include an adhesive film or another suitable material to enable the lift-off of the glass substrate 300 later in the fabrication process of the backlight.
  • FIG. 3C is a cross-sectional view of the glass substrate 300 and release layer 140 of FIG. 3B after forming a redistribution layer 102 on the release layer 140.
  • the redistribution layer 102 may be formed by depositing a first metal (e.g., copper) layer on the release layer 140 and patterning the first metal layer to form a patterned first metal layer 106a.
  • a dielectric (e.g., resin) layer may then be deposited over the exposed portions of the release layer 140 and the patterned first metal layer 106a and patterned to form a patterned dielectric layer 104.
  • a second metal (e.g., copper) layer may then be deposited over the exposed portions of the patterned first metal layer 106a and the patterned dielectric layer 104 and patterned to form a patterned second metal layer 106b.
  • the first metal layer and the second metal layer may be sputtered, sputtered and plated, or a foil.
  • FIG. 3D is a cross-sectional view of the glass substrate 300, release layer 140, and redistribution layer 102 of FIG. 3C after applying a solder resist layer 170 over the redistribution layer 102.
  • a solder resist layer may be deposited over exposed portions of the patterned dielectric layer 104 the patterned second metal layer 106b and patterned to form patterned solder resist layer 170.
  • the patterned solder resist layer 170 includes openings 172 for light sources 108.
  • the solder resist layer 170 can be white for improved reflectivity which may reduce the degree to which the adhesive layer 120 need be reflective.
  • FIG. 3E is a cross-sectional view of the glass substrate 300, release layer 140, redistribution layer 102, and patterned solder resist layer 170 of FIG. 3D after electrically coupling a plurality of light sources 108 (one light source is illustrated in FIG. 3E) to the redistribution layer 102.
  • a first contact 110a and a second contact 110b of each light source 108 may be electrically coupled to the patterned second copper layer 106b via solder 112.
  • SMT Surface mount technology
  • solder resist layer 170 may remain on redistribution layer 102.
  • FIGS. 4A and 4B are simplified cross-sectional views of exemplary backlight fabrication steps.
  • FIG. 4A is a cross-sectional view of attaching a patterned glass diffuser 122 fabricated as indicated in a FIG. 2A-2G to a glass circuit board fabricated as indicated in FIGS. 3A-3E.
  • an adhesive 120 is applied to the patterned glass diffuser 122 and/or to the redistribution layer 102.
  • adhesive layers 120 and 150 may be applied to the patterned glass diffuser 122 and/or to the redistribution layer 102 as illustrated in FIG. 1G or a patterned reflective film 160 and adhesive 120 may be applied to the patterned glass diffuser 122 and/or to the redistribution layer 102 as illustrated in FIG. 1H.
  • the patterned glass diffuser 122 is attached to the redistribution layer 102, such that the variable diffuser pattern 130 is aligned with the plurality of light sources 108.
  • Pressure may be applied to the patterned glass diffuser 122 and the glass substrate 300 to squeeze excess adhesive out until the second surface 126 of the glass substrate 128 almost reaches the top surface of the plurality of light sources 108 using a rolltype (line pressure) or plate-type (area pressure) press machine.
  • the plurality of light sources 108 may function as spacers between the patterned glass diffuser 122 and the redistribution layer 102.
  • a small amount of adhesive may remain for optical bonding, which may improve scattering compared to no gap between the second surface 126 of the glass substrate 128 and the top surface of each light source 108.
  • the alignment between the plurality of light sources 108 and the variable diffuser pattern 130 may be checked and adjusted for improved optical performance prior to curing the adhesive 120. Once the adhesive 120 is cured, performing alignment might be difficult due to adhesive consolidation.
  • the glass substrate 300 may remain attached to the redistribution layer 102 in the completed backlight. In other embodiments, the glass substrate 300 may be removed from the redistribution layer 102 as illustrated in FIG. 4B.
  • FIG. 4B is a cross-sectional view of removing the glass substrate 300 from the redistribution layer 102.
  • the release layer 140 remains on the redistribution layer 102 when the glass substrate 300 is removed from the redistribution layer 102.
  • the release layer 140 may remain on the glass substrate 300 when the glass substrate 300 is removed from the redistribution layer 102.
  • One advantage of removing release layer 140 from the redistribution layer 102 is that access to both metal layers is provided with connector 142 facilitating interconnection to driver circuitry.
  • glass substrate 1J may be attached to the redistribution layer 102 via the release layer 140 or another suitable layer (e.g., adhesive, solder, etc.).
  • a thinner form factor backlight may be fabricated and the cost of the glass substrate 300 is avoided as that substrate can then be recycled and used again to fabricate a GCB.
  • Glass substrate 300 improves the dimensional stability with a high transition temperature (Tg), warpage resistance, and high rigidity to improve light source 108 transfer yield.
  • glass substrate 128 may maintain the functions of glass substrate 300 after glass substrate 300 is removed.
  • FIGS. 5A-5H are flow diagrams illustrating an exemplary method 500 for fabricating a backlight, such as a backlight lOOa-lOOi previously described and illustrated with reference to FIGS. 1A-1 J.
  • method 500 includes applying a release layer to a first glass substrate.
  • method 500 may include applying a release layer 140 to a first glass substrate 300 as illustrated in FIG. 3B.
  • method 500 includes forming a redistribution layer on the release layer.
  • method 500 may include forming a redistribution layer 102 on the release layer 140 as illustrated in FIG. 3C.
  • method 500 includes electrically coupling a plurality of light sources to the redistribution layer.
  • method 500 may include electrically coupling a plurality of light sources 108 to the redistribution layer 102 as illustrated in FIG. 3E.
  • method 500 includes applying an adhesive over the redistribution layer and the plurality of light sources.
  • method 500 may include applying an adhesive 120 over the redistribution layer 102 and the plurality of light sources 108 as illustrated in FIG. 4A.
  • method 500 includes attaching a second glass substrate to the adhesive.
  • method 500 may include attaching a second glass substrate 128 to the adhesive 120 as illustrated in FIG. 4A.
  • method 500 includes removing the first glass substrate from the redistribution layer.
  • method 500 may include removing the first glass substrate 300 from the redistribution layer 102 as illustrated in FIG. 4B.
  • method 500 may further include forming a variable diffuser pattern on a first surface of the second glass substrate.
  • method 500 may include forming a variable diffuser pattern 130 on a first surface 124 of the second glass substrate 128 as illustrated in FIG. 2B.
  • Forming the variable diffuser pattern may comprise printing the variable diffuser pattern.
  • attaching the second glass substrate to the adhesive comprises attaching the second glass substrate to the adhesive to align the variable diffuser pattern with the plurality of light sources.
  • method 500 may further include forming a uniform diffuser pattern on the first surface or a second surface of the second glass substrate opposite the first surface.
  • method 500 may include forming a uniform diffuser pattern 132 on the first surface 124 of the second glass substrate 128 as illustrated in FIG. 2D or on a second surface 126 of the second glass substrate 128 as illustrated in FIG. 2C.
  • method 500 may further include testing the plurality of light sources and repairing defective light sources prior to applying the adhesive.
  • method 500 may include testing the plurality of lights sources 108 and repairing defective light sources after electrically coupling the plurality of light sources 108 to the redistribution layer 102 as illustrated in FIG. 3E.
  • method 500 may further include attaching a function layer to the redistribution layer after removing the first glass substrate.
  • method 500 may include attaching a function layer 180 as illustrated in FIG. 1J to the redistribution layer 102 after removing the first glass substrate 300 as illustrated in FIG. 4B.
  • FIG. 1J the redistribution layer
  • method 500 may further include applying a solder resist layer over the redistribution layer prior to applying the adhesive.
  • method 500 may include applying a solder resist layer 170 over the redistribution layer 102 as illustrated in FIG. 3D prior to applying the adhesive 120 as illustrated in FIG. 4A.
  • method 500 may further include applying a reflective adhesive layer over the redistribution layer.
  • method 500 may further include applying a scattering adhesive layer over the reflective adhesive layer.
  • method 500 may include applying a reflective adhesive layer 120 over the redistribution layer 102, and applying a scattering adhesive layer 150 over the reflective adhesive layer 120 as illustrated in FIG. 1G.
  • FIG. 1G As illustrated in FIG.
  • method 500 may further include applying a patterned reflective film to the second glass substrate prior to attaching the second glass substrate to the adhesive.
  • method 500 may include applying a patterned reflective film 160 to the second glass substrate 128 as illustrated in FIGS. 2E-2F prior to attaching the second glass substrate 128 to the adhesive 120 as illustrated in FIG. 2G.
  • FIG. 6 illustrates an exemplary multi-tile backlight fabrication process 600.
  • a patterned glass diffuser 620 is fabricated (e.g., as previously described and illustrated with reference to FIGS. 2A-2G).
  • the patterned glass diffuser 620 may be fabricated to be the full size of the backlight.
  • a plurality of glass circuit boards tiles 622o to 6222 (three tiles are illustrated at 604) are fabricated on glass substrates 621 (e.g., as previously described and illustrated with reference to FIGS. 3A-3E).
  • the size (e.g., length and width) of each glass circuit board tile 622o to 6222 may be limited by the light source (e.g., LED) transfer process.
  • the light source e.g., LED
  • each glass circuit board tile 622o to 6222 may be selected to limit the number of light sources on each board to simplify testing and/or repairing of each glass circuit board and/or to reduce the likelihood of fabricating glass circuit boards that cannot be repaired.
  • the glass circuit board tiles 622o to 622s may be cut to size, light sources (e.g., LEDs) may be transferred to the glass circuit board tiles, the light sources function check may be performed, and light sources may be repaired if they fail the function check.
  • the patterned glass diffuser 620 may be integrated with a first glass circuit board 622o (e.g., as previously described and illustrated with reference to FIG. 4A).
  • the glass substrate of the glass circuit board tile 622o may be removed, exposing the flexible connector 624o of the glass circuit board (e.g., as previously described and illustrated with reference to FIG. 4B).
  • the process of 608 and 610 is repeated three more times, such that glass circuit boards 622o to 622g with flexible connectors 624o to 6243. respectively, are attached to the pattern glass diffuser 620. While four glass circuit board tiles 622o to 622g are illustrated in FIG.
  • a function layer 630 may be laminated to the glass circuit board tiles 622o to 622g (e.g., as previously described and illustrated with reference to FIG. 1 J) depending upon the application.

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Planar Illumination Modules (AREA)

Abstract

Un rétroéclairage comprend un diffuseur en verre à motif, une couche de redistribution, une pluralité de sources de lumière et un adhésif. Le diffuseur en verre à motif comprend un substrat de verre et un motif de diffuseur variable sur une première surface du substrat de verre. La pluralité de sources de lumière est électriquement couplée à la couche de redistribution et à proximité d'une seconde surface du substrat de verre opposée à la première surface. L'adhésif se trouve entre la couche de redistribution et le diffuseur de verre à motif.
PCT/US2023/017247 2022-04-19 2023-04-03 Rétroéclairages comprenant des diffuseurs en verre à motif et procédés de fabrication des rétroéclairages WO2023204962A1 (fr)

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US202263332373P 2022-04-19 2022-04-19
US63/332,373 2022-04-19

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080100772A1 (en) * 2006-11-01 2008-05-01 Au Optronics Corporation Reflective Light Source Device and Manufacture Method Thereof
US20200183234A1 (en) * 2018-12-11 2020-06-11 Lg Display Co., Ltd. Backlight Unit and Display Device Including the Same Technical Field
WO2021221905A1 (fr) * 2020-04-29 2021-11-04 Corning Incorporated Dispositifs d'affichage avec composants en carreaux
US20210397049A1 (en) * 2018-11-12 2021-12-23 Corning Incorporated Backlight including patterned reflectors, diffuser plate, and method for fabricating the backlight
KR20220027077A (ko) * 2019-07-01 2022-03-07 다이니폰 인사츠 가부시키가이샤 확산 부재, 적층체, 확산 부재의 세트, led 백라이트 및 표시 장치

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080100772A1 (en) * 2006-11-01 2008-05-01 Au Optronics Corporation Reflective Light Source Device and Manufacture Method Thereof
US20210397049A1 (en) * 2018-11-12 2021-12-23 Corning Incorporated Backlight including patterned reflectors, diffuser plate, and method for fabricating the backlight
US20200183234A1 (en) * 2018-12-11 2020-06-11 Lg Display Co., Ltd. Backlight Unit and Display Device Including the Same Technical Field
KR20220027077A (ko) * 2019-07-01 2022-03-07 다이니폰 인사츠 가부시키가이샤 확산 부재, 적층체, 확산 부재의 세트, led 백라이트 및 표시 장치
WO2021221905A1 (fr) * 2020-04-29 2021-11-04 Corning Incorporated Dispositifs d'affichage avec composants en carreaux

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