WO2019046328A1 - Réflecteur multicouche pour rétroéclairages à éclairage direct - Google Patents

Réflecteur multicouche pour rétroéclairages à éclairage direct Download PDF

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Publication number
WO2019046328A1
WO2019046328A1 PCT/US2018/048386 US2018048386W WO2019046328A1 WO 2019046328 A1 WO2019046328 A1 WO 2019046328A1 US 2018048386 W US2018048386 W US 2018048386W WO 2019046328 A1 WO2019046328 A1 WO 2019046328A1
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WO
WIPO (PCT)
Prior art keywords
light
backlight unit
mol
area
reflector
Prior art date
Application number
PCT/US2018/048386
Other languages
English (en)
Inventor
Dmitri Vladislavovich Kuksenkov
Xiang-Dong Mi
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
Priority to CN201880062874.6A priority Critical patent/CN111133249B/zh
Priority to KR1020207008898A priority patent/KR102637705B1/ko
Priority to JP2020512690A priority patent/JP7391013B2/ja
Publication of WO2019046328A1 publication Critical patent/WO2019046328A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • 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
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0055—Reflecting element, sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
    • G02B6/0061—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide to provide homogeneous light output intensity
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0066—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form characterised by the light source being coupled to the light guide
    • G02B6/0068—Arrangements of plural sources, e.g. multi-colour light sources
    • 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

Definitions

  • the disclosure relates generally to backlight units and display or lighting devices comprising such backlight units, and more particularly to backlight units comprising a patterned glass light guide plate and a patterned reflective layer.
  • LCDs are commonly used in various electronics, such as cell phones, laptops, electronic tablets, televisions, and computer monitors.
  • LCDs can comprise a backlight unit (BLU) for producing light that can then be converted, filtered, and/or polarized to produce the desired image.
  • BLUs may be edge-lit, e.g., comprising a light source coupled to an edge of a light guide plate (LGP), or back-lit, e.g., comprising a two-dimensional array of light sources disposed behind the LCD panel.
  • LGP light guide plate
  • LCDs can also be considered light valve-based displays in which a display panel comprises an array of individually addressable light valves using a pair of polarizers and an electrically controlled liquid crystal layer.
  • a BLU is required to produce an emissive image from the LCD. Due to high efficiency and small size of state-of-the-art light emitting diodes (LED), most modern BLUs utilize LEDs.
  • BLUs come in two varieties. Edge-lit BLUs comprise a linear LED array edge-coupled to a light guide plate (LGP) that emits light from its surface. Direct-lit BLUs comprise a 2D array of LEDs directly behind the LCD panel. Direct-lit BLUs may have the advantage of improved dynamic contrast as compared to edge-lit BLUs.
  • a display with a direct-lit BLU can independently adjust the brightness of each LED to optimize the dynamic range of the brightness across the image. This is commonly known as local dimming.
  • the light source(s) may be positioned at a distance from the LGP and/or the diffuser film, thus making the overall display thickness greater than that of an edge-lit BLU.
  • Lenses positioned over the LEDs have also been proposed to improve the lateral spread of light in direct-lit BLUs, but the optical distance between the LED and the diffuser film in such configurations, e.g., from about 15-20 mm, still results in an undesirably high overall display thickness and/or these assemblies may produce undesirable optical losses as the BLU thickness is decreased. While edge-lit BLUs may be thinner, the light from each LED can spread across a large region of the LGP such that turning off individual LEDs or groups of LEDs may have only a minimal impact on the dynamic contrast ratio. Direct-lit BLUs also have an advantage as they can enable improved dynamic contrast by employing 2D local dimming, where LEDs in dark regions of the screen can be turned off.
  • the disclosure relates, in various embodiments, to a design for and a method of making a multi-layer patterned reflector comprising two or more layers, where each of the layers is designed such that it has a first area and a second area, the first area being more reflective than the second area, and the second area being more transmissive than the first area.
  • the multi-layer patterned reflector can be optimized for use in thin directly-lit LCD backlights where it serves to spread the light of discrete LED sources in the plane of the backlight by multiple reflections between the patterned reflector and uniform back plane reflector and thereby provide brightness uniform illumination to the LCD panel.
  • a method of making the multi-layer patterned reflector can comprise using a reflective white paint or ink and applying that paint or ink to a suitable glass or plastic substrate by printing multiple layers in succession using a digital printing technology.
  • the patterned reflector can have several layers, each patterned with a relatively low resolution, which can be simply and inexpensively fabricated by printing using highly reflective ink. When such reflectors are used in a directly lit backlight, it allows for smaller thickness, better light utilization efficiency and better brightness uniformity than prior art directly lit backlights using variable reflectors.
  • the same printing process can also be used to make light extraction features
  • FIG. 1 illustrates a light guide plate and an array of light sources optically coupled to the light guide plate
  • FIG. 2 illustrates an exemplary patterned reflective layer according to certain embodiments of the disclosure
  • FIG. 3-4 illustrates a cross sectional view of exemplary BLUs according to various embodiments of the disclosure
  • FIGS. 5A-B illustrate the lateral spreading of light within light guide plates
  • FIGS. 6A-D are plots of light extraction efficiency for exemplary BLUs with various patterned reflective layers
  • FIG. 7 illustrates a LGP patterned with microstructures according to additional embodiments of the disclosure.
  • FIGS. 8A-8B illustrate some embodiments of a multilayer variable reflector according to some embodiments of the disclosure.
  • backlight units comprising a light guide plate having a light emitting first major surface, an opposing second major surface, and a plurality of light extraction features; at least one light source optically coupled to the second major surface of the light guide plate; a rear reflector positioned proximate the second major surface of the light guide plate; and a patterned reflective layer positioned proximate the first major surface of the light guide plate, the patterned reflective layer comprising at least one optically reflective component and at least one optically transmissive component. Display and lighting devices comprising such backlight units are also disclosed herein.
  • Devices comprising such backlights are also disclosed herein, such as display, lighting, and electronic devices, e.g., televisions, computers, phones, tablets, and other display panels, luminaires, solid-state lighting, billboards, and other architectural elements, to name a few.
  • display e.g., televisions, computers, phones, tablets, and other display panels, luminaires, solid-state lighting, billboards, and other architectural elements, to name a few.
  • FIG. 1 illustrates a top view of an exemplary light guide plate (LGP) 100 and an array of light sources 110 optically coupled to the LGP 100.
  • LGP light guide plate
  • the light sources 110 are visible through the LGP 100 in FIG. 1 , although this may not be the case in some embodiments.
  • the LGP 100 may have any dimensions, such as length L and width W, which can vary depending on the display or lighting application.
  • the length L can range from about 0.01 m to about 10 m, such as from about 0.1 m to about 5 m, from about 0.5 m to about 2.5 m, or from about 1 m to about 2 m, including all ranges and subranges therebetween.
  • the width W can range from about 0.01 m to about 10 m, such as from about 0.1 m to about 5 m, from about 0.5 m to about 2.5 m, or from about 1 m to about 2 m, including all ranges and subranges therebetween.
  • Each light source 110 in the array of light sources may also define a unit block (represented by dashed lines) having an associated unit length Lo and unit width Wo, which can vary depending on the dimensions of the LGP 100 and the number and/or spacing of the light sources 110 along the LGP 100.
  • the unit width W 0 and/or unit length L 0 may be less than or equal to about 150 mm, such as ranging from about 1 mm to about 120 mm, from about 5 mm to about 100 mm, from about 10 mm to about 80 mm, from about 20 mm to about 70 mm, from about 30 mm to about 60 mm, or from about 40 mm to about 50 mm, including all ranges and subranges therebetween.
  • the length L and the width W of the LGP may, in some embodiments be substantially equal or they may be different.
  • the unit length L 0 and the unit width W 0 may be substantially equal or they may be different.
  • the LGP 100 may have any regular or irregular shape as appropriate to produce a desired light distribution for a chosen application.
  • the LGP 100 may comprise four edges as illustrated in FIG. 1 , or may comprise more than four edges, e.g. a multi-sided polygon. In other embodiments, the LGP 100 may comprise less than four edges, e.g., a triangle.
  • the LGP may comprise a rectangular, square, or rhomboid sheet having four edges, although other shapes and configurations are intended to fall within the scope of the disclosure including those having one or more curvilinear portions or edges.
  • the LGP may comprise any transparent material used in the art for lighting and display applications.
  • transparent is intended to denote that the LGP has an optical transmission of greater than about 80% over a length of 500 mm in the visible region of the spectrum (-420-750nm).
  • an exemplary transparent material may have greater than about 85% transmittance in the visible light range over a length of 500 mm, such as greater than about 90%, greater than about 95%, or greater than about 99% transmittance, including all ranges and subranges therebetween.
  • an exemplary transparent material may have an optical transmittance of greater than about 50% in the ultraviolet (UV) region ( ⁇ 100-400nm) over a length of 500 mm, such as greater than about 55%, greater than about 60%, greater than about 65%, greater than about 70%, greater than about 75%, greater than about 80%, greater than about 85%, greater than about 90%, greater than about 95%, or greater than about 99% transmittance, including all ranges and subranges therebetween.
  • the LGP can comprises an optical transmittance of at least 98% over a path length of 75 mm for wavelengths ranging from about 450 nm to about 650 nm.
  • the optical properties of the LGP may be affected by the refractive index of the transparent material.
  • the LGP may have a refractive index ranging from about 1.3 to about 1 .8, such as from about 1.35 to about 1.7, from about 1 .4 to about 1 .65, from about 1 .45 to about 1 .6, or from about 1 .5 to about 1.55, including all ranges and subranges therebetween.
  • the LGP may have a relatively low level of light attenuation (e.g., due to absorption and/or scattering).
  • the light attenuation (a) of the LGP may, for example, be less than about 5 dB/m for wavelengths ranging from about 420-750 nm.
  • a may be less than about 4 dB/m, less than about 3 dB/m, less than about 2 dB/m, less than about 1 dB/m, less than about 0.5 dB/m, less than about 0.2 dB/m, or even less, including all ranges and subranges therebetween, e.g., from about 0.2 dB/m to about 5 dB/m.
  • the LGP 100 may comprise polymeric materials, such as plastics, e.g., polymethyl methacrylate (PMMA), methyl methacrylate styrene (MS), polydimethylsiloxane (PDMS), or other similar materials.
  • the LGP 100 can also comprise a glass material, such as aluminosilicate, alkali-aluminosilicate,
  • borosilicate alkali-borosilicate, aluminoborosilicate, alkali-aluminoborosilicate, soda lime, or other suitable glasses.
  • suitable glasses suitable for use as a glass light guide include, for instance, EAGLE XG ® , LotusTM, Willow ® , IrisTM, and Gorilla ® glasses from Corning Incorporated.
  • Some non-limiting glass compositions can include between about 50 mol % to about 90 mol% Si0 2 , between 0 mol% to about 20 mol% AI2O3, between
  • R is any one or more of Li, Na, K, Rb, Cs and x is 2, or Zn, Mg, Ca, Sr or Ba and x is 1.
  • the glass comprises less than 1 ppm each of Co, Ni, and Cr.
  • the concentration of Fe is ⁇ about 50 ppm, ⁇ about 20 ppm, or ⁇ about 10 ppm.
  • the glass comprises between about 60 mol % to about 80 mol% S1O2, between about 0.1 mol% to about 15 mol% AI2O3, 0 mol% to about 12 mol% B2O3, and about 0.1 mol% to about 15 mol% R x O, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2, or Zn, Mg, Ca, Sr or Ba and x is 1.
  • the glass composition can comprise between about 65.79 mol % to about 78.17 mol% S1O2, between about 2.94 mol% to about 12.12 mol% AI2O3, between about 0 mol% to about 1 1.16 mol% B2O3, between about 0 mol% to about 2.06 mol% L12O, between about 3.52 mol% to about 13.25 mol% Na20, between about 0 mol% to about 4.83 mol% K2O, between about 0 mol% to about 3.01 mol% ZnO, between about 0 mol% to about 8.72 mol% MgO, between about 0 mol% to about 4.24 mol% CaO, between about 0 mol% to about 6.17 mol% SrO, between about 0 mol% to about 4.3 mol% BaO, and between about 0.07 mol% to about 0.1 1 mol% Sn0 2 .
  • the glass can comprise an RxO/A Os ratio between 0.95 and 3.23, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2.
  • the glass may comprise an RxO/A Os ratio between 0.95 and 3.23, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2.
  • the glass may comprise an RxO/A Os ratio between 0.95 and 3.23, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2.
  • the glass may comprise an RxO/A Os ratio between 0.95 and 3.23, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2.
  • the glass may comprise an RxO/A Os ratio between 0.95 and 3.23, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2.
  • the glass may comprise an RxO/A Os ratio between 0.95 and 3.23
  • the glass can comprise an RxO - AI2O3 - MgO between -4.25 and 4.0, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2.
  • the glass may comprise between about 66 mol % to about 78 mol% S1O2, between about 4 mol% to about 1 1 mol% AI2O3, between about 4 mol% to about 1 1 mol% B2O3, between about 0 mol% to about 2 mol% L12O, between about 4 mol% to about 12 mol% Na20, between about 0 mol% to about 2 mol% K2O, between about 0 mol% to about 2 mol% ZnO, between about 0 mol% to about 5 mol% MgO, between about 0 mol% to about 2 mol% CaO, between about 0 mol% to about 5 mol% SrO, between about 0 mol% to about 2 mol% BaO, and between about 0 mol% to about 2 mol% Sn02.
  • the glass can comprise between about 72 mol % to about 80 mol% S1O2, between about 3 mol% to about 7 mol% AI2O3, between about 0 mol% to about 2 mol% B2O3, between about 0 mol% to about 2 mol% L12O, between about 6 mol% to about 15 mol% Na20, between about 0 mol% to about 2 mol% K2O, between about 0 mol% to about 2 mol% ZnO, between about 2 mol% to about 10 mol% MgO, between about 0 mol% to about 2 mol% CaO, between about 0 mol% to about 2 mol% SrO, between about 0 mol% to about 2 mol% BaO, and between about 0 mol% to about 2 mol% Sn02.
  • the glass can comprise between about 60 mol % to about 80 mol% S1O2, between about 0 mol% to about 15 mol% AI2O3, between about 0 mol% to about 15 mol% B2O3, and about 2 mol% to about 50 mol% R x O, wherein R is any one or more of Li, Na, K, Rb, Cs and x is 2, or Zn, Mg, Ca, Sr or Ba and x is 1 , and wherein Fe + 30Cr + 35Ni ⁇ about 60 ppm.
  • the LGP 100 can comprise a color shift Ay less than 0.015, such as ranging from about 0.005 to about 0.015 (e.g., about 0.005, 0.006, 0.007, 0.008, 0.009, 0.010, 0.01 1 , 0.012, 0.013, 0.014, or 0.015).
  • the LGP can comprise a color shift less than 0.008.
  • Color shift may be characterized by measuring variation in the x and y chromaticity coordinates along the length L using the CIE 1931 standard for color measurements. For LGPs the color shift Ay can be reported as where l_2 and Li are Z positions along the panel or substrate direction away from the source launch and where l_2- meters.
  • Exemplary LGPs have Ay ⁇ 0.01 , Ay ⁇ 0.005, Ay ⁇ 0.003, or Ay ⁇ 0.001 .
  • the LGP can have a light attenuation ai (e.g., due to absorption and/or scattering losses) of less than about 4 dB/m, such as less than about 3 dB/m, less than about 2 dB/m, less than about 1 dB/m, less than about 0.5 dB/m, less than about 0.2 dB/m, or even less, e.g., ranging from about 0.2 dB/m to about 4 dB/m, for wavelengths ranging from about 420-750 nm.
  • ai e.g., due to absorption and/or scattering losses
  • the LGP 100 may, in some embodiments, comprise glass that has been chemically strengthened, e.g., ion exchanged.
  • ions within a glass sheet at or near the surface of the glass sheet may be exchanged for larger metal ions, for example, from a salt bath.
  • the incorporation of the larger ions into the glass can strengthen the sheet by creating a compressive stress in a near surface region.
  • a corresponding tensile stress can be induced within a central region of the glass sheet to balance the compressive stress.
  • Ion exchange may be carried out, for example, by immersing the glass in a molten salt bath for a predetermined period of time.
  • exemplary salt baths include, but are not limited to, KNO3, L1NO3, NaNC , RbN03, and combinations thereof.
  • the temperature of the molten salt bath and treatment time period can vary. It is within the ability of one skilled in the art to determine the time and temperature according to the desired application.
  • the temperature of the molten salt bath may range from about 400°C to about 800°C, such as from about 400°C to about 500°C
  • the predetermined time period may range from about 4 to about 24 hours, such as from about 4 hours to about 10 hours, although other temperature and time combinations are envisioned.
  • the glass can be submerged in a KNO3 bath, for example, at about 450°C for about 6 hours to obtain a K-enriched layer which imparts a surface compressive stress.
  • the reflective layer may have at least two regions with different optical properties.
  • the patterned reflective layer can comprise optically reflective components 120A (represented by white dots), which may have an optical reflectance that is higher than that of optically transmissive components 120B (represented by black dots) and/or the transmissive components 120B may have an optical transmittance that is greater than that of the reflective components 120A.
  • optically reflective components 120A represented by white dots
  • optically transmissive components 120B represented by black dots
  • the transmissive components 120B may have an optical transmittance that is greater than that of the reflective components 120A.
  • two exemplary light sources 110 are visible through the patterned reflective layer 120 in FIG. 2, although this may not be the case in some embodiments.
  • a first region 125A may be more densely populated with reflective components 120A in areas corresponding to at least one light source 110, as illustrated in FIG. 2.
  • a second region 125B may similarly be more densely populated with transmissive components 120B in areas between the light sources 110, as illustrated in FIG. 2.
  • first regions 125A of high reflectance and/or low transmittance can be distributed in a higher density above each discrete light source 110 in the array of light sources and second regions 125B of low reflectance and/or high transmittance may be distributed in a higher density in areas adjacent or between the light sources.
  • the patterned reflective layer 120 may comprise any material capable of at least partially modifying the light output from the LGP 100.
  • the patterned reflective layer 120 may comprise a patterned metallic film, a multi-layer dielectric film, or any combination thereof.
  • the reflective and transmissive components 120A, 120B and/or the first and second regions 125A, 125B of the patterned reflective layer 120 may have different diffuse or specular reflectance.
  • the patterned reflective layer 120 may adjust the amount of light transmitted by the LGP 100.
  • the reflective and transmissive components 120A, 120B and/or the first and second regions 125A, 125B of the patterned reflective layer 120 may have different transmittance.
  • a first reflectance of the first region 125A may be about 50% or greater and a second reflectance of the second region 125B may be about 20% or less.
  • the first reflectance may be at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or at least about 92%, such as ranging from about 50% to 100%, including all ranges and subranges therebetween.
  • the second reflectance may be about 20% or less, about 15% or less, about 10% or less, or about 5% or less, such as ranging from 0% to about 20%, including all ranges and subranges therebetween.
  • the first reflectance may be at least about 2.5 times greater than the second reflectance, e.g., about 3 times greater, about 4 times greater, about 5 times greater, about 10 times greater, about 15 times greater, or about 20 times greater, such as from about 2.5 to about 20 times greater, including all ranges and subranges therebetween.
  • Reflectance of the patterned reflective layer 120 may be measured, for example, by a UV/Vis spectrometer available from Perkin Elmer.
  • a first transmittance of the first region 125A may be about 50% or less and the second transmittance of second region 125B may be about 80% or greater.
  • the first transmittance may be about 50% or less, about 40% or less, about 30% or less, about 20% or less, or about 10% or less, such as ranging from 0% to about 50%, including all ranges and subranges therebetween.
  • the second transmittance may be 80% or greater, about 85% or greater, about 90% or greater, or about 95% or greater, such as from about 80% to 100%, including all ranges and subranges therebetween.
  • the second transmittance may be at least about 1.5 times greater than the first transmittance, e.g., about 2 times greater, about 3 times greater, about 4 times greater, about 5 times greater, about 10 times greater, about 15 times greater, or about 20 times greater, such as from about 1 .5 to about 20 times greater, including all ranges and subranges therebetween.
  • Transmittance of the patterned reflective layer 120 may be measured, for example, by the UV/Vis spectrometer available from Perkin Elmer.
  • the reflective and/or transmissive components 120A, 120B may be positioned in the reflective layer 120 to produce any given pattern or design, which may, for example, be random or arranged, repetitive or non-repetitive, uniform or non-uniform.
  • FIG. 2 illustrates an exemplary repeating pattern of reflecitve and transmissive components 120A, 120B, it is to be understood that other patterns, both regular and irregular, may be used and are intended to fall within the scope of the disclosure.
  • these components may form a gradient, e.g., a gradient of decreasing reflectance from the first region 125A to the second region 125B, from the light sources to the areas between the light sources, or from the center of each unit block to the edges and/or corners of each unit block.
  • the reflective and transmissive components can form a gradient of increasing transmittance from the first region 125A to the second region 125B, from the light sources to the areas between the light sources, or from the center of each unit block to the edges and/or corners of each unit block, and so forth.
  • the LGP 100 may comprise a light emitting first major surface 100A and an opposing second major surface 100B.
  • the major surfaces may, in certain embodiments, be planar or substantially planar and/or parallel or substantially parallel.
  • the LGP 100 may have a thickness t extending between the first and second major surfaces of less than or equal to about 3 mm, for example, ranging from about 0.1 mm to about 2.5 mm, from about 0.3 mm to about 2 mm, from about 0.5 mm to about 1.5 mm, or from about 0.7 mm to about 1 mm, including all ranges and subranges therebetween.
  • the patterned reflective layer 120 may be positioned proximate the first major surface 100A of the LGP 100.
  • the term "positioned proximate" and variations thereof is intended to denote that a component or layer is located near a particular surface or listed component, but is not necessarily in direct physical contact with that surface or component.
  • the patterned reflective layer 120 is not in direct physical contact with first major surface 100A, e.g., an air gap exists between these two components.
  • the patterned reflective layer 120 may be monolithically integrated with the LGP 100, such as disposed on the first major surface 100A of the LGP 100.
  • a component or layer is in direct physical contact with a particular surface or listed component.
  • one or more layers or films may be present between these two components, such as an adhesive layer.
  • a component A positioned proximate a surface of component B may or may not be in direct physical contact with component B.
  • FIG. 3 illustrates a single patterned reflective layer 120
  • the reflective layer 120 may comprise multiple pieces, films, or layers.
  • the patterned reflective layer 120 can be a multi-layer composite film or coating, such as a dielectric coating.
  • portions of the reflective layer corresponding to the first regions 125A may first be applied the LGP 100, and portions of the reflective layer corresponding to the second regions 125B may subsequently be applied to the LGP, or vice versa.
  • a first film or layer having first optical properties may be positioned over one or more portions of the LGP 100 and a second film or layer having second optical properties may be overlaid to cover substantially all of the LGP 100, including the portions covered by the first film.
  • the first region 125A of the multilayer reflective layer can have the aggregate optical properties of the first and second films while the second region 125B can have the optical properties of the second film alone, or vice versa.
  • the patterned reflective layer 120 may thus comprise a single film or a composite film, a single layer or multiple layers, as appropriate to produce the desired optical effect.
  • embodiments disclosed herein can comprise a patterned reflective layer having at least one optical property that is different in first regions 125A (e.g., higher reflectance and/or lower transmittance) as compared to second regions 125B (e.g., lower reflectance and/or higher transmittance).
  • the areal density of the reflective and transmissive components 120A, 120B can vary across the reflective layer 120 such that a higher density of reflective components 120A is present in the first region 125A positioned over the light sources 110 and a higher density of transmissive components 120B is present in the second region 125B positioned between the light sources 110.
  • embodiments of BLUs disclosed herein may produce substantially uniform light, e.g., light emanating from regions corresponding to the light sources may have a luminance that is substantially equal to that of light emanating from regions between the light sources.
  • the at least one light source 110 can be optically coupled to the second major surface 100B of the LGP 100.
  • Non-limiting exemplary light sources can include light-emitting diodes (LEDs), e.g., LEDs emitting blue, UV, or near-UV light, e.g., light having wavelengths ranging from about 100 nm to about 500 nm.
  • LEDs light-emitting diodes
  • the term "optically coupled" is intended to denote that a light source is positioned at a surface of the LGP so as to introduce light into the LGP that at least partially propagates due to total internal reflection.
  • the light sources 110 may be in direct physical contact with the LGP 100 as illustrated in FIG.
  • a light source may also be optically coupled to the LGP even though it is not in direct physical contact with the LGP.
  • an optical adhesive layer 150 may be used to adhere the light sources 110 to the second major surface 100B of the LGP 100 as depicted in FIG. 4.
  • the optical adhesive layer may be index-matched to the LGP 100, e.g., having a refractive index within 10% of the refractive index of the LGP, such as within 5%, within 3%, within 2%, within 1 %, or having the same refractive index as the LGP.
  • the BLU can further comprise a rear reflector 130 positioned proximate the second major surface 100B of the LGP 100.
  • An optical distance OD for light traveling between the two reflectors may thus be defined as the distance between the patterned reflective layer 120 and the rear reflector 130.
  • Exemplary rear reflectors 130 can comprise, for instance, metallic foils, such as silver, platinum, gold, copper, and the like. As further illustrated in FIG.
  • a backlight unit may comprise one or more additional films or components, such as one or more supplemental optical films and/or structural components.
  • supplemental optical films 170 can include, but are not limited to, diffusing films, prismatic films, e.g., a brightness enhancing film (BEF), or reflective polarizing films, e.g., a dual brightness enhancing film (DBEF), to name a few.
  • BEF brightness enhancing film
  • DBEF dual brightness enhancing film
  • the light sources 110 and/or rear reflector 130 may be disposed on a printed circuit board 140.
  • Supplemental optical component(s) such as a diffusing film 160, a color-converting layer 170 (e.g., comprising quantum dots and/or phosphors), a prismatic film 180, and/or a reflective polarizing film 190, may be positioned between the patterned reflective layer 120 and a display panel 200.
  • the BLUs disclosed herein may comprise or may be combined with other components typically present in display and lighting devices, such as a thin film transistor (TFT) array, a liquid crystal (LC) layer, and a color filter, to name a few exemplary components.
  • TFT thin film transistor
  • LC liquid crystal
  • color filter to name a few exemplary components.
  • transmissive components 120B are depicted as dots with varying dimensions representative of their density along the light guide plate, e.g., with low density above the light source 110 and increasing density moving away from the light source 110.
  • the density of the reflective and/or transmissive components 120A, 120B may be increased or decreased by increasing the number and/or size of components.
  • the reflective and/or transmissive components 120A, 120B may have any shape or combination of shapes, including circles, ovals, squares, rectangles, triangles, or any other regular or irregular polygonal shape, including shapes with straight and/or curvilinear edges.
  • a first light ray (dashed arrow) injected into the LGP 100 can travel directly through the LGP without laterally propagating within the LGP 100 and may also pass through second region 120B of the patterned reflective layer 120 without being reflected back through the LGP, resulting in first transmitted light ray T-i .
  • a second light ray (dotted arrow) injected into the LGP 100 can travel directly through the LGP without laterally propagating within the LGP 100, but may strike a reflective component 120A in the patterned reflective layer 120 and travel back through the LGP 100 to the rear reflector 130. The second light ray may thus traverse the optical distance OD one or more times while reflecting between the patterned reflective layer 120 and the rear reflector 130. Eventually, the second light ray will pass through a transmissive component 120B of the patterned reflective layer 120, resulting in second transmitted light ray T2.
  • a third light ray (solid arrow) can be injected into the LGP 100 and may propagate within the LGP due to total internal reflection (TIR), until it strikes a light extraction feature or otherwise strikes a surface of the LGP at an angle of incidence that is less than the critical angle and is transmitted through the LGP.
  • TIR total internal reflection
  • the optical distance traveled by the third light ray can thus be reduced to the thickness t of the LGP 100. While the third light ray may undergo some optical losses during TIR due to absorption by the LGP 100, such optical losses may be relatively small compared to those of the second light ray traveling optical distance OD because they travel shorter vertical and/or horizontal distances.
  • the light rays tend to travel only about one half of the distance between light sources (pitch) before being extracted out of the LGP 100.
  • the light source pitch can correspond to the unit width W 0 (illustrated) or unit length (not illustrated), which can be less than or equal to about 150 mm, or even less than about 80 mm, as discussed with reference to FIG. 1.
  • the third light ray will also pass through a transmissive component 120B of the patterned reflective layer, resulting in third transmitted light ray T 3 .
  • Total internal reflection is the phenomenon by which light propagating in a first material (e.g., glass, plastic, etc.) comprising a first refractive index can be totally reflected at the interface with a second material (e.g., air, etc.) comprising a second refractive index lower than the first refractive index.
  • a first material e.g., glass, plastic, etc.
  • a second material e.g., air, etc.
  • n x sin(0 ; ) n 2 sin(0 r )
  • ni is the refractive index of a first material
  • n ⁇ is the refractive index of a second material
  • ⁇ is the angle of the light incident at the interface relative to a normal to the interface (incident angle)
  • ⁇ ⁇ is the angle of refraction of the refracted light relative to the normal.
  • the incident angle ⁇ i under these conditions may also be referred to as the critical angle 0 C .
  • Light having an incident angle greater than the critical angle ( ⁇ > 0 C ) will be totally internally reflected within the first material, whereas light with an incident angle equal to or less than the critical angle (0i ⁇ 0 C ) will be transmitted by the first material.
  • the critical angle (0 C ) can be calculated as 41 °.
  • the critical angle can be calculated as 41 °.
  • the first and/or second major surface 100A, 100B of the LGP 100 may be patterned with a plurality of light extraction features.
  • the term "patterned" is intended to denote that the plurality of light extraction features is present on or under the surface of the LGP in any given pattern or design, which may, for example, be random or arranged, repetitive or non-repetitive, uniform or non-uniform.
  • the light extraction features may be located within the matrix of the LGP adjacent the surface, e.g., below the surface. For instance, the light extraction features may be distributed across the surface, e.g.
  • Suitable methods for creating such light extraction features can include printing, such as inkjet printing, screen printing, microprinting, and the like, texturing, mechanical roughening, etching, injection molding, coating, laser damaging, or any combination thereof.
  • Non-limiting examples of such methods include, for instance, acid etching a surface, coating a surface with ⁇ 2, and laser damaging the substrate by focusing a laser on a surface or within the substrate matrix.
  • the LGP may be treated to create light extraction features according to any method known in the art, e.g., the methods disclosed in co-pending and co-owned International Patent Application Nos. PCT/US2013/063622 and PCT/US2014/070771 , each incorporated herein by reference in their entirety.
  • a surface of the LGP may be ground and/or polished to achieve the desired thickness and/or surface quality.
  • the surface may then be optionally cleaned and/or the surface to be etched may be subjected to a process for removing contamination, such as exposing the surface to ozone.
  • the surface to be etched may, by way of a non-limiting embodiment, be exposed to an acid bath, e.g., a mixture of glacial acetic acid (GAA) and ammonium fluoride (NH 4 F) in a ratio, e.g., ranging from about 1 :1 to about 9:1.
  • the etching time may range, for example, from about 30 seconds to about 15 minutes, and the etching may take place at room temperature or at elevated temperature.
  • Process parameters such as acid concentration/ratio, temperature, and/or time may affect the size, shape, and distribution of the resulting extraction features. It is within the ability of one skilled in the art to vary these parameters to achieve the desired surface extraction features.
  • the light extraction feature pattern may be chosen to improve uniformity of light extraction along the length and width of the LGP 100, it is possible that the regions of the LGP corresponding to the individual light sources may emit light having a higher intensity, e.g., the overall light output of the LGP may not be uniform.
  • the patterned reflective layer 120 may thus be engineered with regions of varying optical properties to further homogenize the light output. For instance, the patterned reflective layer 120 may provide increased reflectance and/or decreased transmittance in first regions 125A corresponding to the light sources and increased transmittance and/or decreased reflectance in second regions 125B between the light sources. Such a configuration may allow for closer placement of the diffuser film or other optical films with respect to the light sources and, thus, a thinner overall BLU and resulting lighting or display device without negatively impacting the uniformity of light produced by the BLU or device.
  • a light ray is emitted from light source 110 at an emission angle 0 L ED and passes into the LGP 100.
  • the light ray is incident upon the light emitting surface of the LGP at an incident angle 0 L GP, which does not exceed the critical angle 0c and therefore does not result in TIR within the LGP 100.
  • transmission T2 for different emission angles ⁇ LED 20°, 41 °, and 60°, assuming the refractive index (n) of the LGP is 1 .5.
  • the higher order of the reflection R 3 and transmission T 3 is negligible as the total flux is less than 1 %.
  • a light ray is emitted from a light source 110 optically coupled to LGP 100 such that the emission angle ⁇ LED is substantially equal to the incident angle OLGP-
  • the optical coupling e.g., using an index-matched optical adhesive, allows at least a portion of the light to travel laterally along a length of the LGP due to TIR.
  • a portion of the light travels a second lateral distance X 2 ,
  • X2 3Xi , due to reflection between the and is transmitted as second transmission T2.
  • the incident angle exceeds the critical angle, e.g., is greater than about 42° in the depicted configuration, the light ray can undergo TIR, which allows the light to travel significantly greater lateral distances within the LGP before being extracted out. As such, a portion of light can travel a lateral distance X 3 due to TIR and be transmitted as third transmission T 3 .
  • the effect of TIR on lateral light spread can further be demonstrated by comparing backlight assemblies comprising a rear reflector, a patterned reflector, at least one LED, and a LGP positioned between the reflectors.
  • backlight assemblies comprising a rear reflector, a patterned reflector, at least one LED, and a LGP positioned between the reflectors.
  • the bottom reflector has a Lambertian reflectance of 98% and absorbance of 2%;
  • the LED has a Lambertian reflectance of 60% and an absorbance of 40%;
  • the LGP comprises glass having a refractive index of 1.5 and a thickness varying from 0.1 mm to 5 mm, optically coupled to the LED;
  • the patterned reflector has one of four different properties:
  • FIGS. 6A-D which plot light extraction efficiency as a function of LGP/air gap thickness
  • the light extraction efficiency of the assemblies comprising an air gap decreases as the thickness t decreases.
  • the light extraction efficiency of the assemblies comprising a LGP increases as the thickness t decreases from 5 mm to about 0.7 mm.
  • the light extraction efficiency of the assemblies comprising a LGP is significantly higher than that of the assemblies with an air gap for thicknesses of about 2 mm and below.
  • modifications to decrease the overall thickness of the BLU are likewise desirable. By positioning an optically coupled LGP between the patterned reflective layer and the rear reflector, optical losses that may otherwise occur as the distance between the reflectors is decreased can be mitigated and the overall thickness of the BLU can be effectively reduced.
  • microstructures 105 on the first major surface 100A of the LGP 100.
  • These microstructures 105 can serve, in some embodiments, to redirect normal incidence light toward an off-axis angle to further encourage lateral spread of light from the light source and/or to reduce optical losses due to absorption by the light sources, e.g., LEDs.
  • the light extraction efficiency may be improved in such embodiments as much as 5% compared to configurations without microstructures on the LGP, such as ranging from about 1 % to about 4%, or from about 2% to about 3%, including all ranges and subranges therebetween.
  • the microstructures 105 may have a pyramidal shape, which can be individual raised features (as illustrated) or linear grooves. Raised microstructures can be constructed, for instance, from the same or different material as the LGP, such as glasses and plastics. The raised
  • microstructures can be made, for instance, by molding or microprinting the microstructures on the first major surface 100A. In further embodiments, the microstructures can be imprinted or etched into the first major surface 100A.
  • the base angle ⁇ ⁇ the microstructures make with the first major surface 100A can range from about 20° to about 40°, such as from about 25° to about 35°, or about 30°, including all ranges and subranges
  • FIGS. 8A-8B illustrate some embodiments of a multilayer variable reflector according to some embodiments of the disclosure.
  • one non-limiting embodiment is illustrated having an LED size of approximately 1 mm x 1 mm and an LGP thickness of about 1 mm.
  • the pitch (center to center distance) of the LEDs in this non-limiting embodiment is 100 mm with a size of the individual 2D dimming zone or the area one LED illuminates being 100 mm x 100 mm.
  • an exemplary reflective paint may transmit about 95% of incoming light and, if a first layer of the reflector only lets 5% of the light out, then the second layer should transmit between 2% and 4% of the incoming light. In embodiments where the second layer is completely opaque, this would correspond to a pattern feature size in the second layer of between about 0.42 mm by 0.42 mm and 0.6 mm by 0.6 mm. Such a feature size is easier to manufacture than the embodiment described in FIG. 8A and it can be easier to achieve a more uniform brightness.
  • FIGS. 8A and 8B thus illustrate that two features may be varied in exemplary embodiments, one being the size of the pattern features (e.g., "holes” or “islands") and the other transmissivity / reflectivity for each of the reflective layers, to keep the ratio of feature size to layer thickness within the range easily accessible for printing.
  • Any suitable digital printing technology can be used, depending on the type of reflective ink or paint available, such as inkjet printing, screen printing, flexographic printing, or the like.
  • an advantage of using white paint or ink as a reflector material in the thin backlight design is that paints typically have diffuse rather than specular reflectivity, which will aid avoiding too many reflected light rays returning back to the LED source and further increase the backlight efficiency.
  • an exemplary variable reflector can be printed on the top surface of the LGP as well as on any other suitable surface above the LGP, for example a bottom surface of an optical diffuser plate, diffuser sheet, or brightness enhancement film (BEF). If an exemplary variable reflector is printed on the LGP, an additional advantage provided to a corresponding display is that light extraction features can be printed in the same pass as the first layer of the variable reflector since white paint is widely known in the art as an efficient light extractor.
  • BEF brightness enhancement film
  • an exemplary variable reflector is printed on the bottom surface of a BEF, diffuser, or other component of the backlight other than the LGP, then the presence of the LGP may not be necessary but can still provide the advantages of ease of manufacture and higher brightness uniformity.
  • multiple samples were prepared by printing commercially available white ink LH-100 with a Mimaki UJF7151 plus printer on a glass with different thickness d.
  • a cosine corrected bidirectional transmission distribution function (ccBTDF) was measured over each sample with an Imaging Sphere for Scatter and Appearance (IS-SA) detector (available from Radiant Imaging, Inc.) and a light source with a normal incidence and at a wavelength of 550 nm (ccBTDF(O) at zero degree was determined to be a good metric for the transmitted intensity).
  • a cosine corrected bi-directional reflection distribution function (ccBRDF) was also measured with the same instrument.
  • ccBRDF(O) could not be obtained; however, total integrated scattering (TIS_R) from ccBRDF was determined to be a good metric to quantify the reflected light.
  • Table 5 below provides TIS_R and ccBTDF(O) at zero degree vs. relative ink thickness d/dO for a wavelength of 550 nm.
  • transmitted light intensity of the normal incidence quantified by ccBTDF(O)
  • ccBTDF(O) can be varied more than 3 orders of magnitude by controlling the thickness of the white ink. It should be noted that when the ink thickness is 2xd0 or thicker, the transmitted light intensity may be too low to be accurately measured.
  • the total integrated scattering of the reflected light can vary from about 21 % to about 93%.
  • the BLUs disclosed herein may be used in various display devices including, but not limited to televisions, computers, phones, handheld devices, billboards, or other display screens.
  • the BLUs disclosed herein may also be used in various illuminating devices, such as luminaires or solid state lighting devices.
  • a backlight unit comprising a substrate comprising a light emitting first major surface and an opposing second major surface, at least one light source optically coupled to the substrate, and a reflector positioned proximate first or second major surface of the substrate, the reflector comprising two or more layers of a reflective material with each of the layers having a first area and a second area, the first area being more reflective than the second area, and the second area being more transmissive than the first area.
  • the substrate comprises glass.
  • the glass may comprise a composition, on a mol% oxide basis with 50-90 mol% Si0 2 , 0-20 mol% AI2O3, 0-20 mol% B2O3, and 0-25 mol% RxO, wherein x is 2 and R is chosen from Li, Na, K, Rb, Cs, and combinations thereof, or wherein x is 1 and R is chosen from Zn, Mg, Ca, Sr, Ba, and
  • the substrate comprises a color shift Ay of less than about 0.015. In other embodiments, the substrate comprises a thickness ranging from about 0.1 mm to about 2 mm.
  • the reflective material is a white ink and wherein a total integrated scattering of reflection from the white ink varies between 4% and 93%.
  • the substrate is a volume diffuser plate, surface diffusive sheet, light guide plate, brightness enhancement film, or a reflective polarizer.
  • the at least one light source is optically coupled to the second major surface of the light guide plate through an optical adhesive layer.
  • a backlight unit comprising a substrate comprising a light emitting first major surface and an opposing second major surface, a plurality of discrete light sources, a reflector positioned proximate the second major surface, and a multi-layer patterned reflector positioned proximate the first major surface, each layer having a first area and a second area, the first area being more reflective than the second area, and the second area being more transmissive than the first area.
  • the discrete light sources are located below the multi-layer patterned reflector and above the bottom reflector, and the light emitted by the light sources travels laterally between the bottom reflector and the patterned reflector due to multiple reflections at the reflective surfaces of the bottom reflector and the patterned reflector.
  • the substrate comprises glass.
  • the glass may comprise a composition, on a mol% oxide basis with 50-90 mol% Si0 2 , 0-20 mol% AI2O3, 0-20 mol% B2O3, and 0-25 mol% RxO, wherein x is 2 and R is chosen from Li, Na, K, Rb, Cs, and combinations thereof, or wherein x is 1 and R is chosen from Zn, Mg, Ca, Sr, Ba, and
  • the substrate comprises a color shift Ay of less than about 0.015. In other embodiments, the substrate comprises a thickness ranging from about 0.1 mm to about 2 mm. In some embodiments, the substrate is a volume diffuser plate, surface diffusive sheet, light guide plate, brightness enhancement film, or a reflective polarizer. In some embodiments, the at least one light source is optically coupled to the second major surface of the light guide plate through an optical adhesive layer.
  • Additional embodiments provide a backlight unit comprising a substrate comprising a light emitting first major surface, an opposing second major surface, and a plurality of patterned features on the first or second major surfaces, a plurality of discrete light sources, a reflector positioned proximate the second major surface, and a multi-layer patterned reflector positioned proximate the first major surface, each of the layers having a first area and a second area, the first area being more reflective than the second area, and the second area being more transmissive than the first area.
  • the discrete light sources are located directly behind the patterned substrate, and wherein the light from the discrete light sources is optically coupled to the patterned glass light guide such that a first portion of the light travels laterally in the patterned glass light guide due to the total internal reflection and extracted out by the pattern of light extractors and a second portion of the light travels laterally between the bottom reflector and the patterned reflector due to multiple reflections at the reflective surfaces of the bottom reflector and the patterned reflector.
  • the substrate comprises glass.
  • the glass may comprise a composition, on a mol% oxide basis with 50-90 mol% S1O2, 0-20 mol% AI2O3, 0-20 mol% B2O3, and 0-25 mol% R x O, wherein x is 2 and R is chosen from Li, Na, K, Rb, Cs, and combinations thereof, or wherein x is 1 and R is chosen from Zn, Mg, Ca, Sr, Ba, and combinations thereof.
  • the substrate comprises a color shift Ay of less than about 0.015.
  • the substrate comprises a thickness ranging from about 0.1 mm to about 2 mm.
  • the substrate is a volume diffuser plate, surface diffusive sheet, light guide plate, brightness enhancement film, or a reflective polarizer.
  • the at least one light source is optically coupled to the second major surface of the light guide plate through an optical adhesive layer.
  • the substrate is a patterned glass light guide plate having a pattern of light extractors on both the first and second major surfaces.
  • the terms “the,” “a,” or “an,” mean “at least one,” and should not be limited to “only one” unless explicitly indicated to the contrary.
  • reference to “a light source” includes examples having two or more such light sources unless the context clearly indicates otherwise.
  • a “plurality” or an “array” is intended to denote “more than one.”
  • a “plurality of light scattering features” includes two or more such features, such as three or more such features, etc.
  • an “array of holes” includes two or more such holes, such as three or more such holes, and so on.
  • Ranges can be expressed herein as from “about” one particular value, and/or to "about” another particular value. When such a range is expressed, examples include 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 aspect. 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.
  • substantially similar may denote values within about 10% of each other, such as within about 5% of each other, or within about 2% of each other.

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Abstract

La présente invention concerne des ensembles guides de lumière comprenant une unité de rétroéclairage ayant un substrat comprenant une première surface principale émettant de la lumière et une seconde surface principale opposée, au moins une source de lumière optiquement couplée au substrat, et un réflecteur positionné à proximité d'une première ou d'une seconde surface principale du substrat, le réflecteur comprenant deux couches ou plus d'un matériau réfléchissant, chacune des couches ayant une première zone et une seconde zone, la première zone étant plus réfléchissante que la seconde zone, et la seconde zone étant plus transmissive que la première zone.
PCT/US2018/048386 2017-08-29 2018-08-28 Réflecteur multicouche pour rétroéclairages à éclairage direct WO2019046328A1 (fr)

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CN201880062874.6A CN111133249B (zh) 2017-08-29 2018-08-28 用于直接发光的背光的多层反射器
KR1020207008898A KR102637705B1 (ko) 2017-08-29 2018-08-28 직접 조명 백라이트들을 위한 다중층 반사부
JP2020512690A JP7391013B2 (ja) 2017-08-29 2018-08-28 直下型バックライト用の多層反射器

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KR102637705B1 (ko) 2024-02-19
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TW201921057A (zh) 2019-06-01
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CN111133249A (zh) 2020-05-08
JP7391013B2 (ja) 2023-12-04

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