JP2019532481A - Color conversion light guide plate and apparatus including color conversion light guide plate - Google Patents

Abstract

This specification discloses a light guide plate having a diffractive feature and a color conversion feature. An optical assembly comprising at least one light source optically coupled to such a light guide plate is also disclosed. In addition, display devices, lighting devices, and electronic devices that include such assemblies are also disclosed herein.

Description

Cross-reference of related applications

  This application claims the benefit of priority over US Provisional Patent Application No. 62 / 384,417 filed on September 7, 2016 under Section 119 of the US Patent Act. Depends on the contents of the provisional application, which is hereby incorporated by reference in its entirety.

  The present disclosure relates generally to light guide plates and display or lighting devices including such light guide plates, and more particularly to light guide plates having color conversion features and light diffraction features.

  Liquid crystal displays (LCDs) are commonly used in various electronics, such as cell phones, laptops, electronic tablets, televisions, and computer monitors. Conventional LCDs typically include light emitting diodes (LEDs) and color converting elements, such as phosphors or quantum dots (QDs). LEDs may also be used in combination with color conversion elements in lighting applications such as luminaires. The light guide assembly includes one or more “white” LEDs optically coupled to a light guide plate (LGP) having one or more light extraction features for scattering light in a desired direction. There is.

  White LEDs can be made, for example, by coating a blue light emitting LED with a silicone / phosphor slurry that can convert the light to green and / or red light as it passes through. The combination of blue light, green light, and red light is perceived as white light by the human eye. However, silicone can darken over time after prolonged exposure to LED flux and heat. Moreover, phosphors tend to have poor color gamut compared to other color conversion elements (eg, QD) due to their relatively broad emission spectrum.

Accordingly, it would be useful to provide lighting and display components, such as light guide assemblies, that can use QDs instead of or in addition to conventional phosphors. However, color conversion elements, such as phosphors and QDs, are not 100% quantum efficient in converting light, and some of the light energy may be absorbed as heat by the color conversion element. The color conversion process itself may also generate heat due to Stokes shift, for example when shorter wavelengths are converted to longer wavelengths. In some cases, up to 20 to 40% of the absorbed light may be converted to heat. Since excess heat can degrade the color conversion element, it is important to establish a proper cooling or heat sink path to dissipate the generated heat and maintain the color conversion element within the desired operating temperature. There may be.

  Although phosphorescent materials may be able to operate at moderate temperatures (eg, up to about 300 ° C.), QDs are very temperature sensitive and can degrade at temperatures above about 100 ° C. Because QD is sensitive to temperature, conventional display and lighting assemblies are generally configured to avoid proximity and / or direct contact between the QD and the LED. Therefore, the design of LGP assemblies that include QD as a color conversion element has been difficult to date, if not impossible.

  Accordingly, it would be advantageous to provide an LGP that includes a color conversion feature having a suitable heat dissipation path. It would also be advantageous to provide a color conversion LGP having an improved color gamut. Furthermore, it would be advantageous to provide an LGP with features that are capable of both converting blue light into white light and scattering that light in a desired direction.

  In various embodiments, the present disclosure is a light guide plate that includes a transparent substrate having a light emitting surface and a light emitting surface opposite the light incident surface, the light incident surface including at least one light diffraction feature. The light guide plate, wherein at least one of the surface and the light emitting surface includes at least one color conversion feature.

  According to various embodiments, the at least one color conversion feature may include a cavity that includes a color conversion medium. For example, the cavity may include a light emitting surface and / or a recess in the light incident surface, or the cavity may be between the sealing layer and the light emitting surface and / or between the sealing layer and the light incident surface. May be placed. The sealing layer may be transparent, reflective, or partially reflective in some embodiments, and / or may be continuous or discontinuous. In certain embodiments, the transparent substrate may be patterned with a plurality of light extraction features, and the plurality of light extraction features may have a gradient pattern, such as a periodic pattern, for example. The light extraction feature may be selected from a surface feature or a subsurface feature. According to a non-limiting embodiment, the at least one light diffraction feature can include an array of periodic diffraction gratings or chirped diffraction gratings. The diffraction grating may be, for example, a polymer layer or a metal layer patterned on the light incident surface of the transparent substrate, or one or more laser damage regions, ion exchange regions on the light incident surface of the transparent substrate, Alternatively, a crystallization region may be included.

  An optical assembly that includes LGP optically coupled to at least one light source is also disclosed herein. In certain embodiments, the light source may be optically coupled to the light entrance surface of the LGP. Exemplary light sources may include, for example, light emitting diodes (LEDs) that emit ultraviolet, near ultraviolet, or blue light. According to various embodiments, the light diffraction feature and the light source may be positioned in overlapping alignment with each other and / or the light diffraction feature may propagate light from the at least one light source. May be directed to a predetermined color conversion feature. In addition, display devices, lighting devices, and electronic devices that include such optical assemblies are disclosed herein.

  The present disclosure is further a method of manufacturing an optical assembly, comprising: forming at least one light diffraction feature on a light incident surface of a transparent substrate; and It also relates to a method comprising forming at least one color conversion feature on at least one and optically coupling at least one light source to the at least one light diffraction feature.

  Additional features and advantages of the disclosure will be set forth in the following detailed description, and in part will be readily apparent to those skilled in the art from the description, or the following detailed description, claims, and accompanying drawings will be described. And will be recognized by practicing the method as described herein.

  Both the foregoing general description and the following detailed description are intended to present various embodiments of the disclosure and to provide an overview or framework for understanding the nature and characteristics of the claims. That should be understood. The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the description serve to explain the principles and operations of the disclosure.

The following detailed description can be further understood when read in conjunction with the following drawings, in which like numbers are used to indicate like elements, where possible.
2 illustrates an optical assembly including LGPs according to various embodiments of the present disclosure. 2 illustrates an optical assembly including LGPs according to various embodiments of the present disclosure. 2 illustrates an optical assembly including LGPs according to various embodiments of the present disclosure. 2 illustrates an optical assembly including LGPs according to various embodiments of the present disclosure. FIG. 6 illustrates an optical assembly including an LGP with light extraction features according to additional embodiments of the present disclosure. FIG. 6 illustrates an optical assembly including an LGP with light extraction features according to additional embodiments of the present disclosure.

  In the following, various embodiments of the present disclosure will be described with reference to FIGS. 1-2, which illustrate exemplary embodiments of optical assemblies and light guide plates (LGP). In addition, display devices, lighting devices, and electronic devices including such LGPs and optical assemblies are also disclosed herein. The following overview is intended to provide an overview of the claimed device, and various aspects are described in more detail throughout this disclosure with reference to non-limiting embodiments, and the implementation thereof. The forms are interchangeable with each other in the context of the present disclosure.

  In the present specification, an LGP includes a transparent substrate having a light emitting surface opposite to a light incident surface, the light incident surface including at least one light diffraction feature, and the light incident surface or the light emitting surface. LGP is disclosed, at least one of which includes at least one color conversion feature. Also disclosed herein are optical assemblies that include at least one light source optically coupled to the LGP, as well as display devices, lighting devices, and electronic devices that include such assemblies.

  FIG. 1A illustrates an optical assembly 200 that includes a light guide plate (LGP) 100 according to an embodiment of the present disclosure. The LGP 100 can include a transparent substrate 101 having a light incident surface 110 and a light emitting surface 120 facing the light incident surface 110. The light incident surface and the light emitting surface may be referred to herein as interchangeable “first” and “second” major surfaces, respectively, interchangeably. The light incident surface 110 can include at least one light diffraction feature 105, and the light emitting surface 120 and / or the light incident surface 110 can include at least one color conversion feature. As shown in FIG. 1A, the color conversion feature can include at least one cavity 115 of the light emitting surface 120 that houses the color conversion medium 125. The cavity 115 may be sealed by at least one sealing layer 130, which may be discontinuous (as shown in FIG. 1A) or continuous (as shown in FIG. 1B). Sometimes. Optionally, a reflector 135, such as a metal film or substrate coated with a reflective paint, is in close proximity to the light incident surface 110 to reflect any backscattered light forward (in the direction of light emission). May be provided. In addition, additional reflectors (not shown) may be provided along the end face of the LGP.

  The optical assembly 200 as disclosed herein can include at least one light source 150 optically coupled to the light entrance surface 110 of the LGP 100. As used herein, the term “optically coupled” is intended to indicate that the light source is positioned relative to the LGP so as to introduce or inject light into the LGP. The light source may be optically coupled to the LGP even if it is not in direct physical contact with the LGP. For example, the light source may be positioned in close proximity to the LGP, but does not make physical contact.

  1A shows equally spaced light diffractive features 105 and cavities 115, each having the same size and shape, but any configuration can be used, and any configuration can be It should be understood that it is intended to be within the scope of the disclosure. For example, the light diffractive features 105 and / or cavities 115 may be spaced apart by changing the distance and / or size and / or shape of the light diffractive features 105 and / or cavities 115, and may be as desired. May be varied as necessary to produce a light output of.

  In addition, FIG. 1A shows a cavity 115 as a recess or well in the transparent substrate, but the cavity 115 is also sealed with the light emitting surface 120, for example, as shown in FIG. 1B. It should be understood that it may be formed between layers 130. For example, the sealing layer 130 may include a substrate having one or more recesses, and the cavity 115 may be formed when the sealing layer 130 is bonded to the light emitting surface 120. Alternatively, the color conversion medium 125 can be deposited or patterned on the light emission surface 120, and the color conversion medium 125 can be encapsulated to form the cavity 115 in the light emission surface 120. A sealing layer can be coated over 125. For example, the sealing layer can be deposited on the color conversion medium by sputtering, vapor deposition, and other similar processes.

  Further, in FIGS. 1A-1B, the cavity 115 is shown to be only on the light emitting surface 120, but the cavity 115 may also be on the light incident surface 110, as shown in FIG. 1C, or It should be understood that it may be present on both the light incident surface 110 and the light emitting surface 120, as shown in FIG. 1D. Placing one or more color conversion features on the light entrance surface 110 may provide an additional advantage of scattering light forward without using light extraction features. Thus, the color conversion feature has the dual purpose of converting blue light to longer wavelengths and scattering the converted light forward so that the converted light is transmitted from the light emitting surface. May be helpful. In embodiments including a cavity 115 on the light entrance surface 110, the cavities are spaced between one or more of the light diffractive features 105 as necessary to produce the desired light output. There is. Furthermore, it should be understood that any cavity 115 present on the light incident surface 110 may be sealed using any of the methods disclosed above with reference to the light emitting surface 120. is there.

  According to various embodiments, the LGP 100 may be patterned by one or more light extraction features 160, 160 '. For example, as shown in FIG. 2A, the LGP 100 is a plurality of patterned light emitting surfaces 120 at a suitable density to produce a substantially uniform light output intensity throughout the light emitting surface 120 of the LGP 100. The surface light extraction feature 160 may be included. In other embodiments, the LGP may be patterned by a subsurface light extraction feature 160 ', as shown in FIG. 2B.

  The light extraction feature may cause surface scattering and / or volume scattering of light depending on the depth of the feature on the LGP surface. The size of the light extraction feature can also affect the light scattering characteristics of the LGP. While not wishing to be bound by theory, small features may scatter light back as well as forward, while larger features tend to scatter light primarily forward. Conceivable. Thus, for example, according to various embodiments, the light extraction features may have a correlation length of less than about 100 nm, such as 70 nm, or less than about 50 nm. Moreover, larger extraction features may provide forward light scatter but angular divergence in some embodiments. Thus, in various embodiments, the light extraction features are from about 20 nm to about 500 nm, such as from about 50 nm to about 100 nm, from about 150 nm to about 200 nm, or from about 250 nm, including all ranges and subranges therebetween. May be in the range of correlation length of about 350 nm. The optical characteristics of the light extraction feature can be controlled, for example, by the processing parameters used when producing the extraction feature.

The LGP is disclosed in any known method in the art, such as co-pending co-owned international patent applications Nos. PCT / US2013 / 063622 and PCT / US2014 / 070771. The international patent application, each of which is hereby incorporated by reference in its entirety. Exemplary light extraction features can include scattering particles, such as polymethylmethacrylate (PMMA) particles, SiO ₂ particles, or TiO ₂ particles, which can be printed, coated, or other The light emitting surface 120 of the LGP 100 may be coated by a method. Alternatively, the light scattering feature may be provided by etching or laser damaging the light emitting surface 120 of the LGP 100. The subsurface light extraction features may also be created by laser damage, for example, focusing the laser directly under the light emitting surface 120. Moreover, in certain embodiments, light scattering particles can also be incorporated into the LGP matrix. The surface and subsurface light extraction features 160, 160 ′ may be patterned on or below the light emitting surface 120, as shown, for example, in FIGS. 2A-2B. It is also possible to pattern the LGP matrix anywhere on the matrix.

  As used herein, the term “patterning” means that the light extraction features are present in any given pattern or design, and the light extraction features are, for example, random or aligned, It is intended to indicate that it may be repetitive or non-repetitive, uniform or non-uniform. The light extraction feature on or near the surface of the LGP has, for example, an extraction efficiency per unit length,

[Where:

Where L is the length of the light guide and x is the position along the LGP]. The extraction efficiency per unit length may be used to design the density of light extraction features across the LGP, and the function form of extraction per unit length is a multiple path of light through the LGP. Can be changed to correspond to Accordingly, the density of the light extraction features at any given location along the LGP is controlled to produce a substantially spatially and / or spectroscopically and / or angularly uniform light emission. In that case, the brightness of the emitted light may be substantially constant over the entire light emitting surface. In some embodiments, in order to produce a more uniform light distribution throughout the LGP, the density of the light extraction features is, for example, more denser away from the light source and the distance from the injection point. May change in inverse proportion to.

  According to a non-limiting embodiment, as shown in FIGS. 2A-2B, the light extraction features 160, 160 'may be patterned to form a gradient. For example, the density of the light extraction features 160, 160 ′ proximate to the light source 150 may be adjusted to a point far away from the light source 150, such as two It may be lower than the density of the middle point. In FIGS. 2A-2B, the gradient G is indicated by an arrow pointing from a lower density region to a higher density region. In the case of an arrayed light source, the gradient pattern may include a periodic pattern with lower density regions of extraction features corresponding to the light sources and higher density regions of extraction features between the light sources. . However, it should be understood that various gradient patterns are possible and are intended to be within the scope of this disclosure, depending on the desired light output. Further, FIG. 2A shows an LGP that includes only the surface light extraction feature 160, and FIG. 2B illustrates an LGP that includes only the subsurface light extraction feature 160 ′. It should be understood that combinations of these may be used and are intended to be within the scope of this disclosure.

Referring to FIGS. 1A-1D again, the light L _E which is emitted from at least one light source 150, may be directed through the optical diffraction features 105, diffractive features 105, the light in the desired direction Can be redirected. Then, the light L _D which is diffracted, may strike the region including the color conversion medium 125 after traveling through the LGP100, that is converted at that time to various wavelengths, resulting in converted light L _C is there. Then, the converted light _{L C} is transmitted through the light emitting surface 120 as transmitted light _{T L} after propagating through the LGP100. For example, the light may strike a light extraction feature (not shown), but the light extraction feature may scatter the light at a desired angle, as described in more detail below. .

Diffractive features 105, in certain embodiments, can include a periodic grating or a chirped grating, the periodic grating or a chirped grating, the emitted light L _E along a desired path It can be configured to change direction. Light “diffraction”, as used herein, is intended to indicate the redirection or guidance of a light beam in a desired direction, which is achieved by spreading the light wave, eg, by interference. Sometimes. In contrast, light “scattering” disperses light rays in several different directions, for example by interaction with interfaces between materials having different refractive indices. The diffractive feature 105 can include a structure that utilizes interference effects to change the direction of light incident on the feature. Light diffraction can be used to redirect all or substantially all light incident on the diffraction feature in a predetermined direction or along a predetermined path. In various embodiments, the light diffractive feature may be optically coupled to a light source, for example, the light diffractive feature may be positioned at least partially or completely overlapping and aligned with the light source. Sometimes.

  The light diffraction feature 105 may include, for example, a diffraction grating having a plurality of slits provided on or in the light incident surface 110. The grating can be formed, for example, by patterning a polymer material or a metal material on the light incident surface 110. The light diffraction feature 105 can be formed on the light incident surface 110 of the transparent substrate 101 by any suitable deposition technique known in the art. The polymer material or metal material can be deposited on the surface by a printing method such as, for example, microreplication, 3D printing, or holographic printing. The polymeric or metallic material can be deposited in a pattern, such as an array of slits, or in other embodiments, multiple portions of the polymeric or metallic material are removed after deposition. Thus, the pattern can be produced. Removal techniques can include lithography, masking, etching, UV curing, or other similar processes. Suitable polymeric materials may include, for example, UV curable acrylates, thermosetting epoxy resins, and other similar materials. Exemplary metallic materials may include, but are not limited to, Al, Au, Ag, Pt, Pd, Cu, other similar metals, and alloys thereof.

  The grating can also be made by changing the transparent substrate itself, for example, by laser damaging the light entrance surface 110 to make one or more slits. Laser machining can be used to form diffractive features, such as, for example, arranged periodic diffraction gratings, on the light incident surface. In the case of a glass substrate, the grating can also be provided by ion exchange of one or more regions of the light incident surface 110. For example, the glass substrate may be processed by a local ion exchange process to form a region where light incident on the glass substrate can be diffracted. Exemplary ion exchange processes include thermal and electrical poling techniques, and optionally a molten salt bath immersion with the use of a masking agent. The diffractive feature is formed by local devitrification and subsequent recrystallization of the glass substrate to form a region on the light incident surface that can diffract light incident on the light incident surface. May also be provided on the surface.

  According to various embodiments, the diffraction grating may include a slit having a slit width and / or grating period within the order of the wavelength of the diffracted light. For example, the slit width and / or grating period includes all ranges and subranges therebetween, for example, in the range of about 100 nm to about 1000 nm, less than about 1000 nm, less than about 700 nm, less than about 500 nm, less than about 400 nm, Or it may be less than about 300 nm. In further embodiments, the overall width of the diffraction grating may be selected to correspond to the area where light is projected onto a given region on the light entrance surface, eg, all ranges and between Including partial ranges, for example, from about 2 mm to about 9 mm, from about 3 mm to about 8 mm, from about 4 mm to about 7 mm, or from about 1 mm to about 10 mm in the range of 5 mm to about 6 mm.

As used herein, the term “slit width” is intended to refer to the width of an individual slit in a diffraction grating. The term “grating period” is intended to refer to the distance between individual slits of a diffraction grating. The grating period may determine the angle at which a given wavelength of light is diffracted using, for example, the equation mλ = d ^* sin Θ, where Θ is the angle of diffraction and λ is the It is a wavelength, d is a grating period, and m is an integer representing an interference order. The term “entire width” is intended to refer to the entire dimension of the slits that make up the individual diffraction gratings. The overall width of the grating period may correspond to, for example, the width of a light source such as an LED optically coupled to the grating.

In some embodiments, the emitted light can be redirected to a desired color conversion feature by a light diffraction feature. For example, as shown in FIG. 1A, emitted light L _E is the optical diffraction features 105, can be diverted to the desired cavity 115 including a color conversion medium 125. The route, for example, it is possible to emitted light L _E is selected to move the desired distance before passing through the color conversion medium 125. Referring to Figure 1C, in a non-limiting embodiment, the emitted light L _E is also diverting the light to impinge on the light emitting surface 120 at a desired angle in a region not corresponding to the color conversion feature Is possible. The desired angle is diffracted light L _D is reflected from the light emitting surface 120 by total internal reflection (TIR), so strikes the cavity 115 including a color conversion medium 125 on the light incident surface 110, less than the critical angle May be selected. In a further embodiment, as shown in FIG. 1B, the light diffractive feature 105 is redirected so that the light strikes a predetermined cavity 115 after propagating along the LGP a distance specified by the TIR. There is.

Total internal reflection refers to light propagating in a first material (eg, glass, plastic, etc.) having a first refractive index with a second material (eg, air, etc.) having a second refractive index lower than the first refractive index. This phenomenon allows total reflection at the interface. TIR describes Snell's law describing the refraction of light at the interface between two materials with different refractive indices:
n ₁ sin (θ _i ) = n ₂ sin (θ _r )
Can be used to explain. According to Snell's law, n ₁ is the refractive index of the first material, n ₂ is the refractive index of the second material, and θ _i is the angle of light incident on the interface relative to the normal to the interface ( (Incident angle), and θ _r is a refraction angle of the reflected light with respect to the perpendicular. When the refraction angle (θ _r ) is 90 °, for example, sin (θ ₂ ) = 1, Snell's law is

It can be expressed as. The incident angle θ _i under such conditions may be referred to as a critical angle θ _c . Light having an incident angle larger than the critical angle (θ _i > θ _c ) will be totally internally reflected in the first material, while light having an incident angle less than the critical angle (θ _i ≦ θ _c ). Will be transmitted by the first material.

For the exemplary interface between air (n ₁ = 1) and glass (n ₂ = 1.5), the critical angle (θ _c ) can be calculated as 41 °. Therefore, when light propagating in the glass hits the air-glass interface at an incident angle greater than 41 °, all incident light is reflected from the interface at an angle equal to the incident angle. When the reflected light hits the second interface having the same refractive index relationship as the first interface, the light incident on the second interface is reflected again at a reflection angle equal to the incident angle. Thus, for example, if the glass is a glass plate having two opposing parallel surfaces that define an interface between two opposing air and glass, the light injected into the glass plate It can propagate through the plate and reflects alternately between the parallel first and second interfaces unless or until the interface conditions change.

  Using optical diffraction and / or TIR, the optical assembly may be designed such that the light emitted from the at least one light source travels a predetermined distance before contacting the color conversion medium. Thus, the predetermined path and / or distance of travel may be varied as desired so that the color conversion medium is exposed to the reduced light flux density. Although not wishing to be bound by theory, it is believed that the light flux density of a light beam may decrease as the light beam travels a long distance and spreads spatially. In some embodiments, the flux in the LGP may be reduced by an order of magnitude or even two orders of magnitude. In other words, the diffracted light striking the color conversion medium may have a density as low as 1% of the density of the light originally emitted from the light source. The entire assembly may be operated at a higher light intensity compared to prior art configurations because the light flux density to which the color conversion medium may be exposed could be reduced. Moreover, the lifetime of the optical assembly may be extended compared to prior art devices due to one or more of the above advantages.

  In certain embodiments, a “white” LED coated with a conventional phosphor can be replaced by a blue LED coupled to a QD patterned LGP. Since QD has a narrower emission spectrum than phosphors, the resulting assembly may have an improved color gamut. Of course, in other embodiments, the LGP may be patterned with a color conversion element other than QD, such as a phosphor, a fluorophor, and the like. In a further non-limiting embodiment, the patterned color conversion medium is a light extraction feature conventionally provided on the LGP surface by, for example, coating, coating, laser damage, or other similar processes. Can be completely or partially replaced. Of course, the color conversion LGP disclosed herein may be used in conjunction with additional light extraction features, for example, as shown in FIGS. 2A-2B.

  1 to 2, the color conversion medium 125 may include at least one color conversion element. The color conversion element may in some embodiments be suspended in an organic or inorganic matrix, such as silicone or other suitable material. In certain embodiments, the color conversion element may be suspended in a thermally conductive matrix. According to various embodiments, the color conversion medium includes about all ranges and subranges therebetween, for example, about 10 μm to about 300 μm, about 20 μm to about 200 μm, or about 50 μm to about 100 μm, and so on. May be deposited as a layer having a thickness in the range of 5 μm to about 400 μm.

  The color conversion feature can be formed using any method known in the art. For example, the color conversion medium may be any suitable deposition method, such as a printing method, such as ink jet printing, screen printing, microprinting, etc., a coating method, such as spin coating, slot coating, dip coating, etc. , Pipetting, or any combination thereof can be used to deposit on a surface or in a recess. In certain embodiments, droplets of the color conversion medium suspended in one or more solvents can be deposited in any desired pattern. The solvent may optionally be removed by drying at ambient or elevated temperature.

The at least one color conversion element can be selected, for example, from phosphors, quantum dots (QDs), and lumiphors, such as fluorescent materials, or luminescent polymers. Exemplary phosphors include red and green emitting phosphors such as yttrium and zinc sulfide based phosphors such as yttrium aluminum garnet (YAG), red nitride doped with _Eu2 ⁺ , and combinations thereof Although not limited to these, it is not limited to these.

  The QD can have various shapes and / or sizes depending on the desired wavelength of the emitted light. For example, the frequency of emitted light may increase as the size of the quantum dots decreases, for example, the color of the emitted light shifts from red to blue as the size of the quantum dots decreases. can do. When illuminated with blue light, UV light, or near UV light, the quantum dots may convert the light to longer red, yellow, green, or blue wavelengths. According to various embodiments, the color conversion element can be selected from QDs that emit at red and green wavelengths when illuminated with blue light, UV light, or near UV light.

  In various embodiments, it is possible that at least one cavity 115 includes the same or different types of color conversion elements, eg, elements that emit light of the same wavelength or different wavelengths. For example, in some embodiments, the cavity can include a color conversion element that emits both green and red wavelengths to produce a red-green-blue (RGB) spectrum in the cavity. However, according to other embodiments, it is possible for individual cavities to contain only color conversion elements that emit the same wavelength, for example cavities containing only green quantum dots or cavities containing only red phosphors. In a further embodiment, a single cavity may be subdivided by alternating subcavities filled with green color conversion elements and complementary subcavities filled with red color conversion elements.

  It is within the ability of one skilled in the art to select the configuration of the cavity or multiple cavities and the type and amount of color conversion medium to arrange each cavity to achieve the desired display or lighting effect. Moreover, although described above for red and green emitting elements, any including, but not limited to, red, orange, yellow, green, blue, or any other color in the visible spectrum (eg, about 420-750 nm) It should be understood that any type of color conversion element that can emit light of any wavelength can be used. For example, in solid state lighting applications, quantum dots of various sizes may be combined to emulate the output of a black object, which may provide a great color rendering.

  With continued reference to FIGS. 1-2, the substrate 101 and / or the sealing layer 130 can comprise, for example, a transparent or substantially transparent material, such as glass or plastic. As used herein, the term “transparent” is intended to indicate that a lens, substrate, or material has a light transmission greater than about 80% in the visible spectrum (about 420-750 nm). Is done. For example, the exemplary transparent substrate or lens has a light transmittance of about 85 in the visible light region, such as a light transmission greater than about 90% or greater than about 95%, including all ranges and subranges therebetween. % Light transmittance may be exceeded.

In some embodiments, the LGP 100, the transparent substrate 101, and / or the sealing layer 130 can be in the range of, for example, about 0.005 to about 0.015 (eg, about 0.005, 0.006, 0.007). , 0.008, 0.009, 0.010, 0.011, 0.012, 0.013, 0.014, or 0.015), etc., can include a color shift Δy of less than 0.015. In other embodiments, the transparent substrate can have a color shift of less than 0.008. According to certain embodiments, the LGP 100, the transparent substrate 101, and / or the sealing layer 130 may have a wavelength in the range of about 420-750 nm, for example, in the range of about 0.2 dB / m to about 4 dB / m. For example, 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, even less, less than about 4 dB / m α ₁ (eg, due to absorption and / or scattering losses).

Color shift may be characterized by measuring variations in x and y chromaticity coordinates along the length L using the CIE 1931 standard for color measurement. For glass light guide plates, the color shift Δy can be reported as Δy = y (L ₂ ) −y (L ₁ ), where L ₂ and L ₁ are along the panel or substrate direction away from the light source. Z position, L ₂ −L ₁ = 0.5 meter. Exemplary light guide plates may have Δy <0.01, Δy <0.005, Δy <0.003, or Δy <0.001.

  Suitable transparent materials may include, for example, any glass known in the art for use in display devices and other electronic devices. Exemplary glasses may include aluminosilicate glass, alkali-aluminosilicate glass, borosilicate glass, alkali-borosilicate glass, aluminoborosilicate glass, alkali-aluminoborosilicate glass, and other suitable glasses. However, it is not limited to these. These substrates may be chemically strengthened and / or thermally strengthened in various embodiments. Non-limiting examples of suitable commercially available substrates include Corning Incorporated's EAGLE XG® glass, Lotus® glass, Iris® glass, Willow®, to name a few. ) Glass, and Gorilla (R) glass. In other embodiments, polymeric materials such as plastics, such as polymethyl methacrylate (PMMA), methyl methacrylate styrene (MS), or polydimethylsiloxane (PDMS) may be used as a suitable transparent material.

  Glass chemically strengthened by ion exchange may be suitable as the transparent material 101 according to some non-limiting embodiments. During the ion exchange process, ions in or near or at the surface of the glass plate may be exchanged to obtain larger metal ions, for example from a salt bath. Incorporation of larger ions into the glass can strengthen the sheet by creating a compressive stress in the area near the surface. In order to maintain a balance with the compressive stress, a corresponding tensile stress can be induced in the central region of the glass.

The ion exchange can be performed, for example, by immersing the glass in a molten salt bath for a predetermined time. Exemplary salt baths include, but are not limited to, KNO ₃ , LiNO ₃ , NaNO ₃ , RbNO ₃ , and combinations thereof. The temperature and processing time of the molten salt bath can vary. It is within the ability of one skilled in the art to determine the time and temperature according to the desired application. As a non-limiting example, the temperature of the molten salt bath can range from about 400 ° C. to about 800 ° C., such as, for example, about 400 ° C. to about 500 ° C., and the predetermined processing time can be, for example, about 4 Although it may range from about 4 hours to about 24 hours, such as from time to about 10 hours, other temperature and time combinations are also contemplated. As a non-limiting example, the glass can be immersed, for example, in a KNO ₃ bath at about 450 ° C. for about 6 hours to obtain a K-rich layer that imparts compressive stress to the surface.

In a specific embodiment, the transparent substrate 101 has the following composition:
55 to 75% by weight of SiO ₂ ,
5 to 25% by weight of Al ₂ O ₃ ,
1 to 15% by weight of MgO,
0 to 1% by weight of SnO ₂ ,
0 to 5 wt% Na ₂ O,
0 to 5 wt% SrO, and 0 to 10 wt% B ₂ O ₃
May include glass having According to a further embodiment, the glass may contain less than 200 ppm Fe ₂ O ₃ . In a further embodiment, the glass may contain less than 2 ppm Cr ₂ O ₃ . In further embodiments, the glass may contain less than 2 ppm NiO. According to further embodiments, the glass is less than 1 ppm NiO and Cr ₂ O ₃ and / or less than 100 ppm Fe, such as less than about 50 ppm, less than about 20 ppm, or less than about 10 ppm Fe ₂ O ₃ , respectively. ₂ O ₃ may be included. Additional non-limiting exemplary glass compositions are listed in Table I below, with amounts expressed in weight percent.

  The transparent substrate 101 can have any desired size and / or shape as needed to produce the desired light distribution. Opposing major surfaces of the substrate 101, such as light emitting and light incident surfaces 110, 120, in certain embodiments, may be planar or substantially planar and / or parallel or substantially parallel. There may be. The transparent substrate 101 may have a sheet of four sides, for example, a square or a rectangle, or may have four sides, for example, a polygon polygon, or more than four sides, for example, a triangle. You may have less than sides. As a non-limiting example, the light guide may include a rectangular, square, or rhomboid sheet having four sides, including one having one or more curved portions or sides, Other shapes and configurations are intended to be within the scope of this disclosure. In certain embodiments, the transparent substrate 101 includes, for example, about 0.1 mm to about 2.5 mm, about 0.3 mm to about 2 mm, about 0.5 mm to about 1 including all ranges and subranges therebetween. May have a thickness of 0.5 mm, or about 3 mm or less in the range of about 0.7 mm to about 1 mm.

  In a non-limiting embodiment, the sealing layer 130 can include a reflective layer, such as, for example, a metal, metal oxide, metal alloy, or a mixture thereof. Alternatively, the sealing layer 130 may be a transparent material (eg, glass, plastic, etc.) or non-transparent material (eg, glass or plastic) completely or partially coated with a reflective material (eg, metal or oxide, alloy, salt thereof, etc.). For example, ceramic, glass-ceramic, etc.) can be included. Exemplary reflective metals include, but are not limited to, Al, Au, Ag, Pt, Pd, Cu, other similar metals, and alloys thereof. The reflective or partially reflective sealing layer 130 may be advantageous with respect to providing an opportunity for any blue (unconverted) light that passes through the color conversion medium 125 to be reflected from the sealing layer 130, and The sealing layer 130 may have another chance that the light is converted to the desired wavelength when it passes through the color conversion medium 125 again. The sealing layer 130 including a thermally conductive material may also provide an additional path for dissipating heat generated by the color conversion medium 125. The sealing layer 130 may be continuous as shown in FIG. 1B or discontinuous as shown in FIG. 1A.

  Some non-limiting examples of additional materials that can be used as the sealing layer 130 include tin, zinc, titanium, or copper oxides, indium tin oxide (ITO), low melting point glass (LMG), Or a low liquid phase temperature (LLT) composition. The LMG composition has a glass transition temperature of about 400 ° C. or less, eg, less than about 350 ° C., less than 300 ° C., less than 250 ° C., or less than 200 ° C., such as in the range of about 150 ° C. to about 400 ° C. Can do. Suitable LLT materials may have a liquidus temperature in the range of, for example, about 400 ° C. to about 1000 ° C., for example, less than about 800 ° C., less than 600 ° C., or less than 400 ° C., less than about 1000 ° C. Exemplary LLT or LMG materials may include, for example, tin fluorophosphate glass, tin fluorofluorophosphate glass doped with tungsten, chalcogenide glass, tellurite glass, borate glass, and phosphate glass.

An exemplary tin fluorophosphate glass composition can be represented for each composition of SnO, SnF ₂ , and P ₂ O _{5 in} the corresponding ternary phase diagram. A suitable tin fluorophosphate glass contains 20 to 100 mol% SnO, 0 to 50 mol% SnF ₂ , and 0 to 30 mol% P ₂ O ₅ . These tin fluorophosphate glass compositions can optionally comprise 0 to 10 mol% WO ₃ , 0 to 10 mol% CeO ₂ , and / or 0 to 5 mol% Nb ₂ O ₅ . For example, the composition of a doped tin fluorophosphate starting material suitable for forming a glass sealing layer is 35 mol% to 50 mol% SnO, 30 mol% to 40 mol% SnF2, 15 mol% to 25 mol% P ₂ O ₅ and 1.5 to 3 mol% dopant oxide, such as, for example, WO ₃ , CeO ₂ , and / or Nb ₂ O ₅ . A tin fluorophosphate glass composition according to one particular embodiment comprises about 38.7 mol% SnO, 39.6 mol% SnF ₂ , 19.9 mol% P ₂ O ₅ , and 1.8 mol%. Of niobium-doped tin oxide / tin fluorophosphate / phosphorus pentoxide glass containing Nb ₂ O ₅ . A tin phosphate glass composition according to another embodiment comprises about 27 mole% Sn, 13 mole% P, and 60 mole% O. A suitable tin fluoroborate glass composition comprises 20 to 100 mol% SnO, 0 to 50 mol% SnF ₂ , and 0 to 30 mol% B ₂ O ₃ . These tin fluorophosphate glass compositions may optionally comprise 0 to 10 mol% WO ₃ , 0 to 10 mol% CeO ₂ , and / or 0 to 5 mol% Nb ₂ O ₅ .

In some embodiments, the sealing layer can include B ₂ O ₃ —ZnO—Bi ₂ O ₃ ternary glass. Suitable glasses can include, in some embodiments, about 10 to 80 mol% B ₂ O ₃ , about 5 to 60 mol% Bi ₂ O ₃ , and about 0 to 70 mol% ZnO. In a non-limiting embodiment, the glass composition may comprise about 40 to 75 mole% _B 2 _{O 3,} from about 20 to 45 mole% _Bi 2 _{O 3,} and about 0 to 40 mol% of ZnO Can do. Such glasses may have a relatively low Tg, for example in the range of about 300 ° C. to about 500 ° C., for example, less than about 600 ° C., less than about 500 ° C., or less than about 400 ° C.

  As will be appreciated, the various glass compositions disclosed herein may refer to the composition of the deposited layer or the composition of the source sputtering target. Further embodiments of suitable low Tg glass compositions and methods used to form glass sealing layers from these materials are described in US Pat. No. 5,089,446, assigned to the assignee of the present invention, and Patent Application Nos. 11 / 207,691, 11 / 544,262, 11 / 820,855, 12 / 072,784, 12 / 362,063, 12 / 763,541, 12 / 879,578, and 13 / 841,391, the entire contents of which are incorporated herein by reference.

  The sealing method may include, for example, disposing a sealing layer on the arranged cavities in the light incident surface and / or the light emitting surface, and bonding the sealing layer to the light incident surface or the light emitting surface. it can. The bonding method may include, for example, laser sealing, frit sealing, glass-to-glass welding, or other suitable techniques. An exemplary sealing technique is disclosed in US patent application Ser. No. 14 / 271,797, assigned to the assignee of the present invention, which is hereby incorporated by reference in its entirety. It is done.

  In further embodiments, the transparent substrate and / or sealing layer may include one or more cavities to which a color conversion medium may be deposited. The cavity may be provided to the substrate by, for example, pressing, molding, cutting, or any other suitable method, and a color conversion medium may be applied to the cavity. The color conversion medium may be deposited on the surface of the transparent substrate or in its recess, after which a sealing layer or film is deposited to at least partially enclose the color conversion medium. Sometimes. Examples of the method for depositing the sealing layer include sputtering or vapor deposition.

In various embodiments, the transparent substrate and sealing layer may form a sealed capsule that includes a color conversion medium. With reference to FIGS. 1-2, the cavity 115 may be formed by, for example, laser sealing or otherwise bonding the sealing layer to the transparent substrate 101, or by sputtering the sealing layer onto the transparent substrate, or It may be hermetically sealed by vapor deposition. For example, the cavities may be hermetically sealed so that the cavities do not pass or substantially pass water, moisture, air, and / or other contaminants. As a non-limiting example, a hermetic seal limits oxygen transpiration (diffusion) to less than about 10 ⁻² cm ³ / m ² / day (eg, less than about 10 ⁻³ / cm ³ / m ² / day). And less than about 10 ⁻² cm ³ / m ² / day (eg, less than about 10 ⁻³ cm ³ / m ² / day, less than about 10 ⁻⁴ cm ³ / m ² / day). , Less than about 10 ⁻⁵ cm ³ / m ² / day, or less than about 10 ⁻⁶ cm ³ / m ² / day). In various embodiments, the hermetic seal can substantially prevent water, moisture, and / or air from contacting the color conversion medium protected by the hermetic seal.

  The LGP and optical assembly shown in FIGS. 1 and 2 can be used in a variety of applications, including but not limited to display applications and lighting applications. For example, a lighting device, such as a luminaire or a solid state lighting device, can comprise the optical assembly disclosed herein. In certain embodiments, the optical assembly can be used alone or in an array to mimic the broadband output of the sun. Such assemblies can include various types and / or sizes of color conversion elements that emit various wavelengths, such as, for example, visible wavelengths in the range of 420 to 750 nm. According to various embodiments, the optical assembly disclosed herein can also be incorporated into a backlight unit (BLU) in a display device, such as an LCD, for example.

  It will be appreciated that the various disclosed embodiments may be accompanied by specific features, elements, or steps that are described with reference to that particular embodiment. Although particular features, elements or steps are described in connection with one particular embodiment, it is also recognized that various embodiments may be interchanged or combined with alternative embodiments in various unillustrated combinations or orders. It will be.

  As used herein, “the”, “a”, or “an” means “at least one” and may not be limited to “only one” unless explicitly stated otherwise. Should be understood. Thus, for example, reference to “a cavity” includes examples having one such “cavity” or two or more such “cavities” unless the context clearly indicates otherwise. Similarly, “plurality” or “array” is intended to indicate two or more, so that “array of cavities” or “plurality of” cavities) "means two or more such cavities.

  Ranges can be expressed herein as from “about” one particular value and / or to “about” another particular value. When expressing such a range, examples include from one particular value and / or to the other particular value.

  Similarly, it will be appreciated that when a value is expressed approximately by using the antecedent “about”, the particular value is another aspect. It will be further understood that the end point of each of the ranges is important while associated with the other end point and independent of the other end point.

  All numerical values expressed herein are to be interpreted as including “about”, whether or not stated, unless stated otherwise. It is further understood, however, that each numerical value recited can be accurately conceived, regardless of whether it is expressed as “about” that value. Thus, “less than 10 mm” and “less than about 10 mm” both include “less than about 10 mm” and “less than 10 mm” embodiments.

  Unless otherwise stated, any method described herein is not intended to be construed as requiring that the steps be performed in any particular order. Thus, if a method claim does not actually describe the order in which the steps are to follow, or unless specifically stated in a claim or explanation that the steps are to be limited to a particular order, It is not intended that any particular order be inferred.

  Where various features, elements or steps of a particular embodiment may be disclosed using the transitional phrase “comprising”, at the same time, the transitional phrase “consisting” or “from It should be understood that alternative embodiments are implied, including embodiments that may be described using “consisting essentially of”. Thus, for example, alternative alternative embodiments for methods involving A + B + C include method embodiments consisting of A + B + C and method embodiments consisting essentially of A + B + C.

  It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the spirit and scope of the disclosure. Since changes, combinations, subcombinations, and variations of the disclosed embodiments that incorporate the spirit and essence of this disclosure may occur to those skilled in the art, this disclosure is intended to be within the scope of the appended claims. It should be construed to include equivalents thereof.

  Hereinafter, preferable embodiments of the present invention will be described in terms of items.

Embodiment 1
A transparent substrate having a light emitting surface opposite to the light incident surface,
A light guide plate including a transparent substrate, the light incident surface including at least one light diffraction feature, and at least one of the light incident surface and the light emission surface including at least one color conversion feature; .

Embodiment 2
The light guide plate of embodiment 1, wherein the at least one color conversion feature includes a cavity including a color conversion medium.

Embodiment 3
The light guide plate according to embodiment 2, wherein the color conversion medium includes at least one color conversion element selected from a phosphor, a quantum dot, and Lumiphor.

Embodiment 4
The light guide plate according to the second embodiment, wherein the cavity is hermetically sealed.

Embodiment 5
The light guide plate according to the second embodiment, wherein the cavity includes a concave portion of at least one of the light emitting surface and the light incident surface.

Embodiment 6
And further including a sealing layer bonded to at least one of the light emitting surface and the light incident surface of the transparent substrate, wherein the cavity is a region between the light emitting surface and the sealing layer or the light incident surface. 3. The light guide plate according to the second embodiment, including a region between the sealing layer and the sealing layer.

Embodiment 7
The light guide plate according to embodiment 6, wherein the sealing layer is transparent.

Embodiment 8
The light guide plate according to embodiment 6, wherein the sealing layer is reflective or partially reflective.

Embodiment 9
The light guide plate according to embodiment 6, wherein the sealing layer is discontinuous.

Embodiment 10
The light guide plate of embodiment 1, wherein the transparent substrate is patterned with a plurality of light extraction features.

Embodiment 11
The light guide plate of embodiment 10, wherein the plurality of light extraction features include surface light extraction features or subsurface light extraction features.

Embodiment 12
The light guide plate of embodiment 10, wherein the plurality of light extraction features include a gradient pattern.

Embodiment 13
The light guide plate according to embodiment 12, wherein the gradient pattern is periodic.

Embodiment 14
The light guide plate according to embodiment 1, wherein the transparent substrate is selected from a glass substrate and a plastic substrate.

Embodiment 15
The transparent substrate has the following composition:
55 to 75% by weight of SiO ₂ ,
5 to 25% by weight of Al ₂ O ₃ ,
1 to 15% by weight of MgO,
0 to 1% by weight of SnO ₂ ,
5 to 15% by weight Na ₂ O,
0 to 5 wt% SrO, and 0 to 10 wt% B ₂ O ₃
The light guide plate according to embodiment 1, comprising glass having

Embodiment 16
The glass is
Fe ₂ O ₃ less than 200 ppm,
<2 ppm Cr ₂ O ₃ , or <2 ppm NiO
16. The light guide plate according to embodiment 15, comprising at least one of the above.

Embodiment 17
The light guide plate of embodiment 1, wherein the at least one light diffraction feature comprises an array of periodic diffraction gratings or chirped diffraction gratings.

Embodiment 18
The light guide plate according to embodiment 17, wherein the diffraction grating includes a polymer layer or a metal layer patterned on the light incident surface of the transparent substrate.

Embodiment 19
Embodiment 18. The light guide plate of embodiment 17, wherein the diffraction grating includes one or more laser damage regions, ion exchange regions, or crystallization regions of the transparent substrate.

Embodiment 20.
2. An optical assembly comprising the light guide plate of embodiment 1 optically coupled to at least one light source.

Embodiment 21.
Embodiment 21. The optical assembly of embodiment 20, wherein the at least one light source is optically coupled to the light incident surface of the transparent substrate.

Embodiment 22
Embodiment 21. The optical assembly of embodiment 20, wherein the at least one light source is a diode that emits ultraviolet, near ultraviolet, or blue light.

Embodiment 23
21. The optical assembly of embodiment 20, wherein the transparent substrate includes a plurality of light extraction features arranged in a pattern to produce a substantially spatially uniform transmission of light from the at least one light source.

Embodiment 24.
21. The optical assembly of embodiment 20, wherein the at least one light diffractive feature is positioned in overlapping alignment with the at least one light source.

Embodiment 25
21. The optical assembly of embodiment 20, wherein the at least one light diffraction feature is configured to direct light propagation from the at least one light source to a predetermined color conversion feature.

Embodiment 26.
21. A display device, lighting device, or electronic device comprising the optical assembly according to embodiment 20.

Embodiment 27.
A method of manufacturing an optical assembly comprising:
Forming at least one light diffraction feature on a light incident surface of the transparent substrate;
Forming at least one color conversion feature on at least one of the light incident surface and the opposing light emitting surface of the transparent substrate;
Optically coupling at least one light source to the at least one light diffractive feature.

Embodiment 28.
28. The method of embodiment 27, further comprising patterning the transparent substrate with a plurality of light extraction features.

Embodiment 29.
29. The method of embodiment 28, wherein patterning the plurality of light extraction features includes a printing step or a laser damage step.

Embodiment 30.
Embodiment 27, wherein forming the at least one light diffractive feature comprises patterning a polymer layer or a metal layer on the light incident surface by lithography, microreplication, 3D printing, or holographic printing process. The method described in 1.

Embodiment 31.
28. The embodiment of embodiment 27, wherein forming the at least one light diffractive feature comprises changing the light incident surface by ion exchange, laser exposure, or local devitrification and subsequent recrystallization. Method.

Embodiment 32.
28. The embodiment 27, wherein forming the at least one color conversion feature includes disposing a color conversion medium in at least one cavity of at least one of the light emitting surface or the light incident surface. the method of.

Embodiment 33.
33. The method of embodiment 32, further comprising hermetically sealing the at least one cavity.

Embodiment 34.
Forming the at least one color conversion feature comprises:
Patterning a color conversion medium on at least one of the light emitting surface and the light incident surface;
Applying the sealing layer to encapsulate the color conversion medium.

Embodiment 35.
35. The method of embodiment 34, wherein the sealing layer is deposited by vapor deposition or sputtering.

DESCRIPTION OF SYMBOLS 100 Light-guide plate 101 Transparent substrate 105 Light diffraction characteristic part 110 Light incident surface 115 Cavity 120 Light emission surface 125 Color conversion medium 130 Sealing layer 135 Reflector 140 End surface 150 Light source 160, 160 'Light extraction characteristic part 200 Optical assembly

Claims (15)

A transparent substrate having a light incident surface and a light emitting surface opposed thereto;
The light incident surface includes at least one light diffraction feature;
At least one of the light incident surface and the light emitting surface includes at least one color conversion feature;
A light guide plate comprising a transparent substrate.   The light guide plate of claim 1, wherein the at least one color conversion feature includes a cavity including a color conversion medium.   The light guide plate according to claim 2, wherein the cavity is hermetically sealed.   The light guide plate according to claim 2, wherein the cavity includes a concave portion of at least one of the light emitting surface and the light incident surface.   A sealing layer bonded to at least one of the light emitting surface and the light incident surface of the transparent substrate, wherein the cavity is a region between the light emitting surface and the sealing layer or the light incident surface; The light guide plate according to claim 2, comprising a region between the sealing layer and the sealing layer.   The light guide plate according to claim 5, wherein the sealing layer is transparent.   The light guide plate according to claim 5, wherein the sealing layer is reflective or partially reflective.   The light guide plate according to claim 5, wherein the sealing layer is discontinuous.   The light guide plate according to claim 1, wherein the transparent substrate is patterned with a plurality of light extraction features.   10. An optical assembly comprising a light guide plate according to any one of claims 1 to 9, optically coupled to at least one light source.   A display device, lighting device, or electronic device comprising the optical assembly according to claim 10. A method of manufacturing an optical assembly comprising:
Forming at least one light diffraction feature on a light incident surface of the transparent substrate;
Forming at least one color conversion feature on at least one of the light incident surface and the opposing light emitting surface of the transparent substrate;
Optically coupling at least one light source to the at least one light diffractive feature.   The method of claim 12, further comprising patterning the transparent substrate with a plurality of light extraction features.   The step of forming the at least one color conversion feature comprises disposing a color conversion medium in at least one cavity of at least one of the light emitting surface or the light incident surface. The method described. Forming the at least one color conversion feature comprises:
The method includes: patterning a color conversion medium on at least one of the light emitting surface and the light incident surface; and depositing a sealing layer so as to enclose the color conversion medium. 13. The method according to 13.

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