TW202427026A - Backlights including a patterned diffuser - Google Patents

Abstract

A backlight includes a substrate, a plurality of light sources, a reflective layer, a plurality of elements, and a patterned diffuser. The plurality of light sources are proximate the substrate. The reflective layer is on the substrate and includes a first reflectance. The plurality of elements are proximate the substrate and each element includes a second reflectance different from the first reflectance. The patterned diffuser includes a plurality of patterned reflectors and a plurality of compensation features over the plurality of light sources and the plurality of elements. Each patterned reflector is over a corresponding light source and includes a varying transmittance, and each compensation feature is over a corresponding element.

Description

Backlight including patterned diffuser

Cross-references to related applications

This patent application claims priority to U.S. Provisional Application No. 63/423604, filed on November 8, 2022, the contents of which are incorporated herein by reference in their entirety.

The present invention generally relates to backlights for displays. More particularly, the present invention relates to backlights including patterned diffusers.

Liquid crystal displays (LCDs) are commonly used in a variety of electronic devices, such as cellular phones, laptops, electronic tablets, televisions, and computer monitors. LCDs are shutter-based displays in which the display panel includes an array of individually addressable shutters. The LCD includes a backlight for generating light that is wavelength converted, filtered, and/or polarized to produce the image of the LCD. The backlight can be edge-lit or direct-lit. A side-lit backlight may include an array of light emitting diodes (LEDs) edge-coupled to a light guide that emits light from the surface of the light guide. A direct-lit backlight may include a two-dimensional (2D) LED array located directly behind the LCD panel.

Direct-lit backlights may have the advantage of improved dynamic contrast compared to edge-lit backlights. For example, a display with a direct-lit backlight may independently adjust the brightness of each LED to set the dynamic brightness range of the entire image. This is often referred to as local dimming. However, to achieve the desired light uniformity and/or avoid hot spots in a direct-lit backlight, a diffuser plate or film may be positioned at a distance from the LEDs, resulting in a greater thickness of the overall display compared to an edge-lit backlight. Lenses located above the LEDs have been used in direct-lit backlights to improve lateral diffusion of light. However, the optical distance (OD) between the LEDs and the diffuser plate or film in such configurations (e.g., from at least 10 mm to typically about 20-30 mm) still results in an undesirably large thickness for the overall display, and/or such configurations may produce undesirable optical loss as the backlight thickness decreases. While edge-lit backlights can be thinner, the light from each LED is spread over a large area of the light guide, so that turning off individual LEDs or groups of LEDs has only a very small effect on dynamic contrast.

Some embodiments of the present invention relate to backlights. The backlight includes a substrate, a plurality of light sources, a reflective layer, a plurality of elements, and a patterned diffuser. The plurality of light sources are adjacent to the substrate. The reflective layer is on the substrate and has a first reflectivity. The plurality of elements are adjacent to the substrate, and each element has a second reflectivity different from the first reflectivity. The patterned diffuser includes a plurality of patterned reflectors and a plurality of compensating feature structures located above the plurality of light sources and the plurality of elements. Each patterned reflector is located above a corresponding light source and has a varying transmittance, and each compensating feature structure is located above a corresponding element.

Other embodiments of the present invention relate to a backlight. The backlight includes a substrate, a plurality of light sources, a reflective layer, a plurality of elements, and a patterned diffuser. The plurality of light sources are adjacent to the substrate. The reflective layer is on the substrate and has a first reflectivity. The plurality of elements are adjacent to the substrate, and each element has a second reflectivity different from the first reflectivity. The patterned diffuser includes a plurality of patterned reflectors located above the plurality of light sources and the plurality of elements. The plurality of patterned reflectors include an asymmetric reflector located above a corresponding light source disposed adjacent to the corresponding element and a symmetric reflector located above a corresponding light source disposed not adjacent to the corresponding element.

Other embodiments of the present invention relate to backlights. The backlight includes a substrate, a plurality of light sources, a reflective layer, and a patterned diffuser. The plurality of light sources are adjacent to the substrate. The reflective layer is on the substrate. The patterned diffuser includes a plurality of patterned reflectors located above the plurality of light sources. Each patterned reflector is aligned with a corresponding light source. Each patterned reflector has a reflectivity that changes from a first value at a first position to a second value at a second position that is less than the first value, and changes from the second value at the second position to a third value at a third position that is greater than the second value, the first position being located at the center of each patterned reflector, the second position being a first distance from the first position, the third position being a second distance from the first position, and the second distance being greater than the first distance.

Other embodiments of the present invention relate to backlight. The backlight includes a substrate, a plurality of light sources, a reflective layer and a plurality of elements. The plurality of light sources are adjacent to the substrate. The reflective layer is on the substrate and has a first reflectivity. The plurality of elements are adjacent to the substrate, and each element is adjacent to the corresponding first, second, third and fourth nearest light sources among the plurality of light sources. The corresponding center of each of the corresponding first, second, third and fourth light sources is used as a vertex to form a corresponding quadrilateral. Each element has a second reflectivity different from the first reflectivity. The distance between the center of each element and the corresponding first nearest light source is at least about 80% of the distance between the center of the corresponding quadrilateral and the corresponding first nearest light source.

Other embodiments of the present invention relate to a backlight. The backlight includes a substrate, a plurality of dimming zones, a reflective layer, and an element adjacent to the substrate in each dimming zone. Each dimming zone includes a plurality of light sources adjacent to the substrate, and has a first spacing Px and a second spacing Py between the plurality of light sources. The reflective layer is on the substrate and has a first reflectivity. The element has a second reflectivity different from the first reflectivity, and a distance d1 between the center of the element and the nearest light source among the plurality of light sources is provided by the following formula: .

The backlight disclosed herein is a thin direct-lit backlight that can improve light efficiency and uniformity. The backlight has an improved ability to hide the light source and reduce local brightness differences caused by an absorption element and/or the intersection between two or more light source areas, thereby forming a thinner backlight. The improved ability to hide the light source and reduce local brightness differences allows the removal of so-called "hot spots" directly above the light source of the backlight and so-called "dark spots" directly above the absorption element and/or the intersection between two or more light source areas, thereby forming uniform brightness across the entire display.

Other features and advantages will be set forth in the following detailed description and will be apparent to those skilled in the art from the description to a certain extent, or may be learned by practicing the embodiments described herein, including the following detailed description, the claims, and the accompanying drawings.

It should be understood that the foregoing general description and the following detailed description are merely exemplary and are intended to provide an overview or framework for understanding the nature and characteristics of the claimed subject matter. The accompanying drawings are used to provide a further understanding and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate one or more embodiments and together with the specification explain the principles and operation of the various embodiments.

Reference will now be made in detail to embodiments of the present invention, examples of which are shown in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to represent the same or similar parts. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments described herein.

Ranges may be expressed herein as from "about" one particular value and/or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations using the antecedent "about," it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints in each range are significant both in relation to the other endpoint and independently of the other endpoint.

Directional terms used herein, such as up, down, right, left, front, back, top, bottom, vertical, horizontal, etc., refer only to the drawings and are not intended to imply an absolute orientation.

Unless expressly stated otherwise, it is not intended that any method described herein be construed as requiring that its steps be performed in a particular order, nor that any device be construed as requiring a particular orientation. Thus, in the event that a method claim does not actually describe an order in which its steps are to be performed, or an apparatus claim does not actually describe an order or orientation of individual elements, or in the event that the claim or specification does not otherwise specifically state that the steps are limited to a particular order, or does not describe a particular order or orientation of elements of an apparatus, no order or orientation of any aspect is intended to be inferred. This applies to any possible non-explicit basis of explanation, including logical matters related to arrangement of steps, operational flow, sequence of components or orientation of components, ordinary meanings derived from grammatical structure or punctuation, and the number or type of embodiments described in this specification.

As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "an" element includes embodiments having two or more such elements unless the context clearly dictates otherwise.

Reference is now made to Figures 1A-1F, which illustrate multiple views of an exemplary backlight. Figure 1A is a simplified cross-sectional view of an exemplary backlight 100a. Backlight 100a may include a substrate 102, a reflective layer 104, a plurality of light sources 106, a plurality of elements 107, and a patterned diffuser 108a. Patterned diffuser 108a includes a carrier 110 (e.g., a light guide plate), a plurality of patterned reflectors 112 and 112a, and a plurality of compensating feature structures 118a. A plurality of light sources 106 are adjacent to substrate 102 (e.g., disposed on substrate 102) and are electrically connected to substrate 102. A plurality of elements 107 are adjacent to substrate 102 (e.g., disposed on substrate 102) and are electrically connected to substrate 102. The plurality of light sources 106 and/or the plurality of elements 107 may be electrically connected to backplane electronics on the back side of the substrate 102 via vias (not shown) extending through the substrate 102 .

A reflective layer 104 is located on the substrate 102 and surrounds each light source 106 and each element 107. In some exemplary embodiments, the substrate 102 is reflective and therefore the reflective layer 104 may not be included. A patterned diffuser 108a is located above the plurality of light sources 106 and the plurality of elements 107 and is optically coupled to each light source 106. In some exemplary embodiments, the plurality of light sources 106 may be coupled to the patterned diffuser 108a using an optical adhesive (not shown). The refractive index of the optical adhesive (e.g., phenyl silicone) is greater than or equal to the refractive index of the carrier 110. A plurality of patterned reflectors 112 and 112a and a compensating feature structure 118a are disposed on the upper surface of the carrier 110. In other embodiments, the patterned reflectors 112 and 112a and the compensation feature structure 118a may be disposed on the lower surface of the carrier 110. Each patterned reflector 112 and 112a is located above a corresponding light source 106. Each compensation feature structure 118a is located above a corresponding element 107.

Each element 107 may be adjacent to a light source 106 within a dimming zone. A dimming zone is a group of light sources 106 that can be turned on and off simultaneously. A dimming zone may include any suitable number of light sources 106, such as 4 light sources arranged in two rows and two columns, 9 light sources arranged in three rows and three columns, 16 light sources arranged in four rows and four columns, etc. Each element 107 may be an electronic component, such as a control chip for each dimming zone, or other suitable component. Each element 107 may locally reduce the brightness around the area where each element is located, which may produce mura that affects brightness uniformity. Therefore, a compensating feature 118 a having a higher transmittance (lower reflectance) is formed at a position on the patterned diffuser 108 a corresponding to the element 107 , thereby reducing the influence of the element 107 .

The reflective layer 104 has a first reflectivity, and each element 107 has a second reflectivity different from the first reflectivity. Herein, the first reflectivity of the reflective layer 104 and the second reflectivity of each element 107 are values based on a bidirectional reflectivity distribution function (BRDF). In certain exemplary embodiments, the second reflectivity is less than the first reflectivity. In the embodiment of FIG. 1A , each compensation feature structure 118 a includes an opening extending through the patterned reflector 112 a so that the surface of the carrier 110 is exposed at each compensation feature structure 118 a. Each patterned reflector 112 a is similar to each patterned reflector 112 except for the compensation feature structure 118 a within each patterned reflector 112 a. The transmittance of each compensating feature structure 118a within the patterned reflector 112a is different from the transmittance at the corresponding position of each patterned reflector 112 that does not correspond to the element 107. Therefore, the compensating feature structure 118a changes the transmittance of the patterned reflector 112a arranged with the compensating feature structure compared to the patterned reflector 112 without the compensating feature structure 118a. In this embodiment, since each compensating feature structure 118a includes an opening, each compensating feature structure includes a constant transmittance. In this embodiment, as shown at 130, the center of each patterned reflector 112 and 112a is aligned with the corresponding light source 106 (e.g., the center of the corresponding light source). Additionally, as shown at 132, the center of each compensation feature 118a is aligned with the corresponding element 107 (eg, the center of the corresponding element).

Each patterned reflector 112 and 112a has a varying transmittance and may have a thickness profile along the width or diameter of the patterned reflector, the thickness profile including a substantially flat portion as shown at 113 and a curved portion extending from and surrounding the substantially flat portion 113 as shown at 114. The substantially flat portion 113 may have a rough surface profile (e.g., the thickness of the entire substantially flat portion varies slightly). In certain exemplary embodiments, the thickness of the substantially flat portion 113 varies by no more than plus or minus 20% of the average thickness of the substantially flat portion. In this embodiment, the average thickness measured in a direction perpendicular to the carrier 110 is defined as the maximum thickness of the substantially flat portion (T _max ) plus the minimum thickness of the substantially flat portion (T _min ) divided by 2 (i.e., (T _max +T _min )/2). For example, for an average thickness of the substantially flat portion 113 of about 100 microns, the maximum thickness of the substantially flat portion may be equal to or less than about 120 microns, and the minimum thickness of the substantially flat portion may be equal to or greater than about 80 microns. In other embodiments, the thickness of the substantially flat portion 113 varies by no more than plus or minus 15% of the average thickness of the substantially flat portion. For example, for an average thickness of the substantially flat portion 113 of about 80 microns, the maximum thickness of the substantially flat portion may be equal to or less than about 92 microns, and the minimum thickness of the substantially flat portion may be equal to or greater than about 68 microns.

In other embodiments, the thickness of the substantially flat portion 113 varies by no more than plus or minus 10% of the average thickness of the substantially flat portion. For example, for an average thickness of the substantially flat portion 113 of about 50 microns, the maximum thickness of the substantially flat portion may be equal to or less than about 55 microns, and the minimum thickness of the substantially flat portion may be equal to or greater than about 45 microns. In other embodiments, the thickness of the substantially flat portion 113 varies by no more than plus or minus 5% of the average thickness of the substantially flat portion. The curved portion 114 may be defined by an absolute ratio of the thickness variation to the distance variation from the center of the patterned reflector 112. The slope of the curved portion 114 may decrease with the distance from the center of the patterned reflector 112. In certain exemplary embodiments, the slope is greatest near the substantially flat portion 113, decreases rapidly as one moves away from the center of the patterned reflector 112, and then decreases slowly as one moves further away from the center of the patterned reflector.

The dimension L0 (i.e., width or diameter) of each substantially flat portion 113 as indicated at 120 (in a plane parallel to the substrate 102) may be greater than the dimension (i.e., width or diameter) of each corresponding light source 106 as indicated at 124 (in a plane parallel to the substrate 102). The dimension 120 of each substantially flat portion 113 may be less than the dimension 124 of each corresponding light source 106 multiplied by a predetermined value. In certain exemplary embodiments, when the dimension 124 of each light source 106 is greater than or equal to about 0.5 mm, the predetermined value may be about 2 or about 3, such that the dimension of each substantially flat portion 113 is less than three times the dimension of each light source 106. When the size 124 of each light source 106 is less than 0.5 mm, the predetermined value may be determined based on the alignment capability between the light source 106 and the patterned reflectors 112 and 112 a, so that the size of each substantially flat portion 113 of each patterned reflector 112 and 112 a is in the range of about 100 microns to about 300 microns larger than the size of each light source 106. Each substantially flat portion 113 is large enough to allow each patterned reflector 112 and 112 a to be aligned with the corresponding light source 106, and small enough to achieve appropriate brightness uniformity and color uniformity.

122 represents the dimension L1 (i.e., width or diameter) of each patterned reflector 112 (in a plane parallel to the substrate 102), and 126 represents the spacing P between adjacent light sources 106. Although the spacing is illustrated along one direction in FIG. 1A, the spacing may be different in directions orthogonal to the illustrated direction. For example, the spacing may be about 90, 45, 30, 10, 5, 2, 1, or 0.5 millimeters, greater than about 90 millimeters, or less than about 0.5 millimeters. In certain exemplary embodiments, the ratio L1/P of the dimension 122 of each patterned reflector 112 and 112a to the spacing 126 is in the range of about 0.45 to 1.0. The ratio can vary with the spacing 126 of the light sources 106 and the distance between the emitting surface of each light source and the corresponding patterned reflector 112 and 112a. For example, for a spacing 126 of about 5 mm and a distance between the emitting surface of each light source and the corresponding patterned reflector of about 0.2 mm, the ratio can be equal to about 0.50, 0.60, 0.70, 0.80, 0.90 or 1.0.

Each patterned reflector 112 and 112a reflects at least a portion of the light emitted by the corresponding light source 106 into the carrier 110. Each patterned reflector 112 and 112a has specular reflection and diffuse reflection. The specular reflected light is emitted from the bottom surface of the carrier 110. Although the specular reflected light mainly travels laterally due to reflection between the reflective layer 104 and the carrier 110, or due to reflection between the reflective layer 104 and the color conversion layer, diffuser or diffuser plate (shown in Figure 2 below), some light loss may occur due to incomplete reflection of the reflective layer 104. The diffusely reflected light has an angular distribution of 0 degrees to 90 degrees measured relative to the normal of the carrier 110. About 50% of the diffusely reflected light has an angle greater than the critical angle of total internal reflection ( ). Therefore, the diffusely reflected light can travel laterally without any loss due to total internal reflection until the light is subsequently guided out of the carrier 110 using the patterned reflectors 112 and 112a.

FIG. 1B is a simplified cross-sectional view of an exemplary backlight 100 b. The backlight 100 b is similar to the backlight 100 a previously described and illustrated with reference to FIG. 1A except that a patterned diffuser 108 b is used in place of the patterned diffuser 108 a in the backlight 100 b. The patterned diffuser 108 b includes a carrier 110 (e.g., a light guide plate), a plurality of patterned reflectors 112 and 112 b, and a plurality of compensating feature structures 118 b. The plurality of patterned reflectors 112 and 112 b and the compensating feature structures 118 b are disposed on the upper surface of the carrier 110. In other embodiments, the plurality of patterned reflectors 112 and 112 b and the compensating feature structures 118 b may be disposed on the lower surface of the carrier 110. Each patterned reflector 112 and 112b is located above the corresponding light source 106. Each compensation feature structure 118b is located above the corresponding element 107.

In this embodiment, each compensating feature structure 118b has a transmittance that changes from a lower value closer to the center of the patterned reflector 112b to a higher value farther from the center of the patterned reflector 112b. Each patterned reflector 112b is similar to each patterned reflector 112 except for the compensating feature structure 118b within each patterned reflector 112b. The transmittance of each compensating feature structure 118b within the patterned reflector 112b is different from the transmittance at the corresponding position of each patterned reflector 112 that does not correspond to the element 107. Therefore, the compensating feature structure 118b changes the transmittance of the patterned reflector 112b provided with the compensating feature structure, compared to the patterned reflector 112 without the compensating feature structure 118b. In this embodiment, as shown at 130, the center of each patterned reflector 112 and 112b is aligned with the corresponding light source 106 (e.g., the center of the corresponding light source). In addition, as shown at 132, the center of each compensating feature structure 118b is aligned with the corresponding element 107 (e.g., the center of the corresponding element).

FIG. 1C is a simplified cross-sectional view of an exemplary backlight 100c. Backlight 100c is similar to backlight 100a previously described and illustrated with reference to FIG. 1A, except that patterned diffuser 108c is used in backlight 100c instead of patterned diffuser 108a. Patterned diffuser 108c includes a carrier 110 (e.g., a light guide plate), a plurality of patterned reflectors 112 and 112c, and a plurality of compensating feature structures 118c. The plurality of patterned reflectors 112 and 112c and the compensating feature structures 118c are disposed on the upper surface of carrier 110. In other embodiments, the plurality of patterned reflectors 112 and 112c and the compensating feature structures 118c may be disposed on the lower surface of carrier 110. Each patterned reflector 112 and 112c is located above the corresponding light source 106. Each compensation feature structure 118c is located above the corresponding element 107.

In this embodiment, each compensating feature structure 118c includes a layer having a constant thickness. Each patterned reflector 112c is similar to each patterned reflector 112 except for the compensating feature structure 118c within each patterned reflector 112c. The transmittance of each compensating feature structure 118c within the patterned reflector 112c is different from the transmittance at the corresponding position of each patterned reflector 112 that does not correspond to the element 107. In some embodiments, the transmittance of each compensating feature structure 118c within the patterned reflector 112c is higher than the transmittance at the corresponding position of each patterned reflector 112 that does not correspond to the element 107. In other embodiments, the transmittance of each compensating feature structure 118c within the patterned reflector 112c is lower than the transmittance at the corresponding position of each patterned reflector 112 that does not correspond to the element 107. Therefore, the compensating feature structure 118c changes the transmittance of the patterned reflector 112c arranged with the compensating feature structure compared to the patterned reflector 112 without the compensating feature structure 118c. In this embodiment, since each compensating feature structure 118c has a constant thickness, each compensating feature structure has a constant transmittance. In this embodiment, as shown at 130, the center of each patterned reflector 112 and 112c is aligned with the corresponding light source 106 (e.g., the center of the corresponding light source). Additionally, as shown at 132, the center of each compensation feature 118c is aligned with the corresponding element 107 (eg, the center of the corresponding element).

1D is a simplified cross-sectional view of an exemplary backlight 100d. Backlight 100d is similar to backlight 100a previously described and illustrated with reference to FIG. 1A, except that in backlight 100d, the center of each patterned reflector 112 and 112a is offset relative to the corresponding light source 106 (e.g., the center of the corresponding light source) as shown at 134, and the center of each compensation feature structure 118a is offset relative to the corresponding element 107 (e.g., the center of the corresponding element) as shown at 136. Although the patterned diffuser 108a is illustrated in FIG. 1D as including the patterned reflectors 112 and 112a and the compensating feature 118a to illustrate the offsets 134 and 136, the offsets 134 and 136 may also be applied in the patterned diffuser 108b of FIG. 1B or the patterned diffuser 108c of FIG. 1C.

Due to the asymmetry caused by the compensating feature 118a, the misalignment tolerance of the patterned diffuser 108a in the direction of the compensating feature 118a may become worse. The visibility of the mura becomes asymmetric and increases in the direction of the element 107. With the asymmetric misalignment tolerance, the center of each patterned reflector 112 and 112a can be offset from the center of the corresponding light source 106 in the opposite direction of the corresponding element 107, thereby improving the misalignment sensitivity in the direction of the element 107. The intentional misalignment between the patterned reflectors 112 and 112a can be in the range of about 100 microns to about 200 microns. However, this intentional misalignment may reduce the misalignment sensitivity in the orthogonal direction.

FIG. 1E is a top view of a plurality of light sources 106, a reflective layer 104, and a plurality of elements 107 on a substrate 102 of a backlight 100 (e.g., backlights 100a, 100b, or 100c described and shown previously with reference to FIGS. 1A-1C, respectively). The light sources 106 are arranged in a 2D array comprising a plurality of rows and a plurality of columns. Although 36 light sources 106 are illustrated in FIG. 1E in six rows and six columns, in other embodiments, the backlight 100 may include any suitable number of light sources 106 arranged in any suitable number of rows and any suitable number of columns. The light sources 106 may also be arranged in other periodic patterns, such as a hexagonal or triangular lattice, or in a quasi-periodic or non-strict periodic pattern. For example, the spacing between light sources 106 at the edges and/or corners of the backlight 100 may be smaller.

In certain exemplary embodiments as shown in FIG. 1E , each light source 106 may be rectangular such that the length of each light source 106 is different from the width of each light source 106 . In other embodiments, each light source 106 may have other suitable shapes, such as a square or a circle. In this embodiment, each dimming zone shown at 140 includes four light sources 106 arranged in a 2×2 pattern for each element 107 . The light sources 106 in a row have a first spacing (e.g., center to center) as shown at 142 , and the light sources 106 in a column have a second spacing (e.g., center to center) as shown at 144 . 146 represents the distance between the element 107 and the adjacent light source 106 within each dimming zone 140 (e.g., center to center). In certain exemplary embodiments, the first spacing 142 is different from the second spacing 144 . In other embodiments, the first spacing 142 is equal to the second spacing 144. In the embodiment shown in FIG. 1E, the first spacing 142 is smaller than the second spacing 144.

Since there is more light near the corresponding light source 106, the smaller the distance 146, the more light is absorbed by each element 107. Due to this absorption, the brightness is lower around the location of the element 107. Therefore, in order to mitigate the effect of the lower brightness caused by the element 107, the compensating features (e.g., 118a, 118b, and/or 118c) disclosed herein are formed on the patterned diffuser (e.g., 108a, 108b, and/or 108c).

Referring back to FIGS. 1A-1D , substrate 102 may be a printed circuit board (PCB), a glass or plastic substrate, or other suitable substrate for transmitting electrical signals to each light source 106 and each element 107 to individually control each light source and each element. Substrate 102 may be a rigid substrate or a flexible substrate. For example, substrate 102 may include flat glass or curved glass. For example, the curved glass may have a radius of curvature of less than about 2000 mm, such as a radius of curvature of about 1500, 1000, 500, 200, or 100 mm. For example, the reflective layer 104 may include metal foils such as silver, platinum, gold, copper, etc.; dielectric materials (for example, polymers such as polytetrafluoroethylene (PTFE)); porous polymer materials such as polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polyethylene naphthalate (PEN), polyether sulfone (PES), etc.; multi-layer dielectric interference coatings or reflective inks, which include white inorganic particles such as titanium dioxide, barium sulfate, etc. or other materials suitable for reflecting light and adjusting the color of reflected light and transmitted light, such as color pigments.

For example, each of the plurality of light sources 106 may be an LED (e.g., having a size greater than about 0.5 mm), a mini-LED (e.g., having a size of about 0.1 mm to about 0.5 mm), a micro-LED (e.g., having a size less than about 0.1 mm), an organic LED (OLED), or other suitable light source having a wavelength in the range of about 400 nm to about 750 nm. In other embodiments, each of the plurality of light sources 106 may have a wavelength shorter than 400 nm and/or longer than 750 nm. Light from each light source 106 is optically coupled to the carrier 110. The term "optically coupled" as used herein is intended to mean that the light source is located on a surface of the carrier 110 and is in optical communication with the carrier 110, either directly or through an optically transparent adhesive, so that the light is introduced into the carrier for at least partial propagation due to total internal reflection. Light from each light source 106 is optically coupled to the carrier 110, so that a first portion of the light travels laterally in the carrier 110 due to total internal reflection and is extracted from the carrier by the patterned reflectors 112 and 112a, 112b or 112c and the compensating features 118a, 118b or 118c, and a second portion of the light travels laterally in the carrier 110 due to total internal reflection and is extracted from the carrier by the patterned reflectors 112 and 112a, 112b or 112c and the compensating features 118a, 118b or 118c. 2a, 112b or 112c and compensating features 118a, 118b or 118c and travel laterally between the reflective layer 104 and the patterned reflectors 112 and 112a, 112b or 112c and the compensating features 118a, 118b or 118c or travel laterally between the optical film stack (shown in FIG. 2 ) and the reflective layer 104 due to multiple reflections at the reflective surfaces of the patterned reflectors 112 and 112a, 112b or 112c and the compensating features 118a, 118b or 118c.

According to various embodiments, the carrier 110 may include any suitable transparent material for lighting and display applications. The term "transparent" as used herein is intended to mean that a carrier having a length of 500 mm has an optical transmittance greater than about 70% in the visible region of the optical spectrum (about 420-750 nm). In certain embodiments, an exemplary transparent material having a length of 500 mm may have an optical transmittance greater than about 50% in the ultraviolet (UV) region (about 100-400 nm). According to various embodiments, a carrier having a path length of 50 mm may have an optical transmittance of at least 95% for wavelengths ranging from about 450 nm to about 650 nm.

The optical properties of the carrier may be affected by the refractive index of the transparent material. According to various embodiments, the carrier 110 may have a refractive index in the range of about 1.3 to about 1.8. In other embodiments, the carrier 110 may have a lower optical attenuation level (e.g., due to absorption and/or scattering). For example, for a wavelength in the range of about 420-750 nanometers, the optical attenuation (α) of the carrier 110 may be less than about 5 dB/m. The carrier 110 may include a polymer material, such as a plastic (e.g., polymethyl methacrylate (PMMA), methyl methacrylate styrene (MS), polydimethylsiloxane (PDMS)), polycarbonate (PC), or other similar materials. The carrier 110 may also include a glass material, such as an aluminosilicate, an alkaline aluminosilicate, a borosilicate, an alkaline borosilicate, an aluminum borosilicate, an alkaline aluminum borosilicate, sodium calcium glass, or other suitable glass. Non-limiting examples of commercially available glasses suitable for use as the glass carrier 110 include Eagle XG®, Lotus ^™ , Willow®, Iris ^™ , and Gorilla® glass from Corning. In examples where the substrate 102 includes curved glass, the carrier 110 may also include curved glass to form a curved backlight. In other embodiments, the carrier 110 may have a higher light decay threshold. For example, for wavelengths in the range of approximately 420-750 nm, the optical attenuation (α) of the carrier 110 may be greater than approximately 5 dB/m.

FIG1F is a top view of a plurality of patterned reflectors 112 and 112a and a plurality of compensating feature structures 118a on a carrier 110 of the patterned diffuser 108a previously described and illustrated with reference to FIG1A. Although FIG1F illustrates that the patterned diffuser 108a includes the patterned reflectors 112 and 112a and the compensating feature structures 118a, the features of the patterned diffuser 108a described with reference to FIG1F may also be applied in the patterned diffuser 108b of FIG1B or the patterned diffuser 108c of FIG1C.

Each compensating feature structure 118a, 118b or 118c can be circular (as shown in FIG. 1F) or elliptical. As mentioned above, each compensating feature structure 118a, 118b or 118c has a higher transmittance than the patterned reflector 112a, 112b or 112c on which each compensating feature structure 118a, 118b or 118c is disposed. The size (e.g., width or diameter) of each compensating feature structure 118a, 118b or 118c should be large enough so that a sufficient amount of light can be transmitted to compensate the corresponding element 107. However, the size of each compensating feature structure 118a, 118b, or 118c should not be so large that the compensating feature structure is recognized as a non-uniform phenomenon (Mura) in the backlight. The optimal size of each compensating feature structure 118a, 118b, or 118c may depend on the luminous properties of the light source 106 and the optical film used to recirculate the light within the backlight. For example, for a typical light source with a Lambertian luminous curve, each compensating feature structure may have a size of less than about 1 mm. However, for a light source 106 with a wide-angle luminous curve, each compensating feature structure may have a size of up to about 2 mm.

As described above, each patterned reflector 112 and 112a, 112b or 112c may include a substantially flat portion 113 and a curved portion 114. The substantially flat portion 113 may be more reflective than the curved portion 114, and the curved portion 114 may be more transmissive than the substantially flat portion 113. Each curved portion 114 has a characteristic that changes in a continuous and smooth manner with the distance from the substantially flat portion 113. Although in the embodiment shown in FIG. 1F, the shape of each patterned reflector 112 and 112a is circular, in other embodiments, each patterned reflector 112 and 112a, 112b or 112c may have other suitable shapes (e.g., elliptical, rectangular, hexagonal, etc.). In the case where the patterned reflectors 112 and 112a, 112b or 112c are directly manufactured on the upper surface of the carrier 110, the patterned reflectors 112 and 112a, 112b or 112c increase the ability to hide the light source 106. Manufacturing the patterned reflectors 112 and 112a, 112b or 112c directly on the upper surface of the carrier 110 also saves space.

In some exemplary embodiments, each patterned reflector 112 and 112a, 112b or 112c is a diffuse reflector, so that each patterned reflector 112 and 112a, 112b or 112c scatters part of the light at a sufficiently high angle, so that the light can propagate in the carrier 110 by total internal reflection, thereby further enhancing the efficiency of the backlight. Such light will not then experience multiple reflections between the patterned reflector 112 and 112a, 112b or 112c and the reflective layer 104 or between the optical film stack and the reflective layer 104, thereby avoiding the loss of optical power, thereby improving the backlight efficiency. In some exemplary embodiments, each patterned reflector 112 and 112a, 112b or 112c is a specular reflector. In other embodiments, some areas of each patterned reflector 112 and 112a, 112b or 112c have more diffuse reflective properties and other areas have more specular reflective properties.

For example, each patterned reflector 112 and 112a, 112b or 112c can be formed by printing a pattern with white ink, black ink, metallic ink or other suitable ink (e.g., inkjet printing, screen printing, micro-printing, etc.). The printing density, ink thickness and/or spatial coverage can be varied to form the substantially flat portion 113 and the curved portion 114 of each patterned reflector 112 and 112a, 112b or 112c and the compensating feature structure 118b or 118c of each patterned reflector 112b or 112c. In certain exemplary embodiments, the ink coverage of each compensation feature 118a may be 0%, and the ink coverage of each compensation feature 118b or 118c may be less than 50% (i.e., 50% of the surface area of the carrier 110 is covered by ink at the compensation feature 118b or 118c). Each patterned reflector 112 and 112a, 112b or 112c may also be formed, for example, by first depositing a continuous layer of white or metallic material by physical vapor deposition (PVD) or any number of coating techniques (e.g., slot die or inkjet), and then patterning the layer by photolithography or other known area selective material removal methods. Each patterned reflector 112 and 112a, 112b or 112c may also be formed by other known methods of selectively removing material from the carrier itself, such as by laser ablation or chemical etching of the carrier.

In certain exemplary embodiments, where a white light source 106 is used, the presence of varying densities of different reflective and absorptive materials in the patterned reflector 112 and 112a, 112b, or 112c is advantageous in minimizing color shifts in various dimming zones of the backlight. Multiple reflections of light between the patterned reflector and the reflective layer 104 (FIGS. 1A-1D) may result in more light loss in the red portion of the spectrum than in the blue portion, or vice versa. In such cases, the color shift may be minimized by designing the reflection to be a neutral color, for example, using slightly tinted reflective/absorptive materials or materials with opposite signs of dispersion (in this case, dispersion means the spectral dependence of the reflection and/or absorption). When using a white light source 106, it is preferred that the patterned reflector 112 and 112a, 112b, or 112c reflect and transmit an amount of blue light similar to green and red light. The patterned reflector 112 and 112a, 112b, or 112c may contain micro-sized particles that are larger than a threshold size. For example, for titanium dioxide, the threshold size may be about 140 nanometers, for aluminum oxide, the threshold size may be about 560 nanometers, or for sodium fluoride, the threshold size may be about 750 nanometers. In other examples, the threshold size may be 1, 2, 5, 10, or 20 micrometers. In certain exemplary embodiments using a blue light source 106, it is preferred that the patterned reflector 112 and 112a, 112b, or 112c reflect more blue light than green and red light, and transmit less blue light than green and red light. The patterned reflector 112 and 112a, 112b or 112c may include nano-sized particles that are smaller than a threshold size. For example, for titanium dioxide, the threshold size may be about 140 nanometers, for aluminum oxide, the threshold size may be about 560 nanometers, or for sodium fluoride, the threshold size may be about 750 nanometers.

The patterned diffuser 108a, 108b, or 108c has a spatially varying transmittance or a spatially varying color shift. Since the spatial reflectance and spatial transmittance of the patterned diffuser 108a, 108b, or 108c are correlated, the patterned diffuser also has a spatially varying reflectance. For example, at the same position of the patterned diffuser 108a, 108b, or 108c, a smaller (or larger) reflectance is associated with a larger (or smaller) transmittance.

FIG. 2 is a cross-sectional view of an exemplary liquid crystal display (LCD) 150. The LCD 150 includes a backlight 100a, which includes a patterned diffuser 108a as previously described and shown with reference to FIG. 1A. Although FIG. 2 illustrates that the backlight 100a includes the patterned diffuser 108a, the features of the LCD 150 described with reference to FIG. 2 can also be applied in the backlight 100b of FIG. 1B or the backlight 100c of FIG. 1C. In addition, the backlight of the LCD 150 optionally includes a diffuser plate 152 located above the backlight 100a, a color conversion layer 154 (e.g., a quantum dot film or a phosphor film) located above the diffuser plate 152, a prismatic film 156 located above the color conversion layer 154, and a reflective polarizer 158 located above the prismatic film 156. The LCD 150 also includes a display panel 160 positioned above a reflective polarizer 158 of the backlight. In certain exemplary embodiments, the reflective polarizer 158 may be bonded to the display panel 160.

In order to maintain the alignment between the light source 106 and the patterned reflectors 112 and 112a on the carrier 110 so that the backlight 100a works properly, it is best to keep the patterned reflectors 112 and 112a on the carrier 110 and the light source 106 on the substrate 102 well aligned with each other over a wide range of operating temperatures if the carrier 110 and the substrate 102 are made of the same or similar types of materials. In some exemplary embodiments, the carrier 110 and the substrate 102 are made of the same plastic material. In other embodiments, the carrier 110 and the substrate 102 are made of the same or similar types of glass.

An alternative solution to maintain alignment of the light source 106 and the carrier 110 on the substrate 102 is to use a highly flexible substrate. The highly flexible substrate can be made of polyimide or other high temperature resistant polymer films that allow components to be soldered. The highly flexible substrate can also be made of materials such as FR4 or fiberglass, but with much less thickness than typical. In certain exemplary embodiments, a 0.4 mm thick FR4 material can be used for the substrate 102, which is flexible enough to withstand dimensional changes caused by varying operating temperatures.

3A-3E are multiple views of other exemplary backlights including patterned diffusers. FIG. 3A is a simplified cross-sectional view of an exemplary backlight 100e, and FIG. 3B is a top view of an exemplary backlight 100e. The backlight 100e is similar to the backlight 100a previously described and shown with reference to FIG. 1A, except that a patterned diffuser 108e is used to replace the patterned diffuser 108a in the backlight 100e. The patterned diffuser 108e includes a carrier 110 (e.g., a light guide plate) and a plurality of patterned reflectors 112, 112d, and 112e. The plurality of patterned reflectors 112, 112d, and 112e are disposed on the upper surface of the carrier 110. In other embodiments, the plurality of patterned reflectors 112, 112d, and 112e may be disposed on the lower surface of the carrier 110. The plurality of patterned reflectors 112, 112d and 112e include asymmetric reflectors 112d and 112e located above the corresponding light source 106 disposed adjacent to the corresponding element 107 and a symmetric reflector 112 located above the corresponding light source 106 not disposed adjacent to the corresponding element 107. The asymmetric reflectors 112d and 112e may be elliptical, while the symmetric reflector 112 may be circular or have an elliptical shape with a different area from the asymmetric reflector. In this embodiment, the asymmetric reflectors 112d and 112e are formed to reduce the absorption effect of the element 107.

In some exemplary embodiments, a first asymmetric reflector 112d located above a corresponding first light source 106 is adjacent to a first side of the corresponding element 107 and has a first area, and a second asymmetric reflector 112e located above a corresponding second light source 106 is adjacent to a second side of the corresponding element 107 and has a second area different from the first area. The first light source 106 (e.g., a center 170 of the first light source) can be arranged at a first distance from the corresponding element 107 (e.g., a center 172 of the corresponding element) as shown at 174. The second light source 106 (e.g., a center 170 of the second light source) can be arranged at a second distance from the corresponding element 107 (e.g., a center 172 of the corresponding element) as shown at 176. In some exemplary embodiments, the first light source 106 can be closer to the corresponding element 107 than the second light source 106, so that the distance 174 is less than the distance 176. In this embodiment, the first area of each first patterned reflector 112d is less than the second area of each second patterned reflector 112e. The center of each patterned reflector 112 can be aligned with the corresponding light source 106 (e.g., the center 170 of the corresponding light source), or the center of each patterned reflector 112 can be offset relative to the corresponding light source (e.g., the center 170 of the corresponding light source). The asymmetric patterned reflectors 112d and 112e adjacent to the corresponding element 107 reduce the impact caused by the absorptive element 107 to improve the brightness uniformity of the backlight 100e.

FIG. 3C is a simplified cross-sectional view of an exemplary backlight 100f, and FIG. 3D is a top view of an exemplary backlight 100f. The backlight 100f is similar to the backlight 100e described and shown previously with reference to FIG. 3A and FIG. 3B, except that element 107 is arranged at a different position in the backlight 100f and patterned diffuser 108f is used instead of patterned diffuser 108e. The patterned diffuser 108f includes a carrier 110 (e.g., a light guide plate) and a plurality of patterned reflectors 112 and 112f. The plurality of patterned reflectors 112 and 112f are arranged on the upper surface of the carrier 110. In other embodiments, the plurality of patterned reflectors 112 and 112f can be arranged on the lower surface of the carrier 110. The plurality of patterned reflectors 112 and 112f include an asymmetric reflector 112f located above the corresponding light source 106 disposed adjacent to the corresponding element 107 and a symmetric reflector 112 located above the corresponding light source 106 not disposed adjacent to the corresponding element 107. The asymmetric reflector 112f may be elliptical, while the symmetric reflector 112 may be circular. In this embodiment, the asymmetric reflector 112f is formed to reduce the absorption effect of the element 107.

In some exemplary embodiments, a first asymmetric reflector 112f located above a corresponding first light source 106 is adjacent to a first side of a corresponding element 107, and a second asymmetric reflector 112f (having an opposite orientation) located above a corresponding second light source 106 is adjacent to a second side of the corresponding element 107. The asymmetric reflectors 112f all have the same area. The first light source 106 (e.g., the center 170 of the first light source) can be arranged at a first distance (as shown by 174) from the corresponding element 107 (e.g., the center 172 of the corresponding element). The second light source 106 (e.g., the center 170 of the second light source) can be arranged at a second distance (as shown by 176) from the corresponding element 107 (e.g., the center 172 of the corresponding element). In this embodiment, the first distance 174 is equal to the second distance 176. The center of each patterned reflector 112 can be aligned with the corresponding light source 106 (e.g., the center 170 of the corresponding light source), or the center of each patterned reflector 112 can be offset relative to the corresponding light source (e.g., the center 170 of the corresponding light source). The asymmetric patterned reflector 112f adjacent to the corresponding element 107 reduces the effect caused by the absorptive element 107 to improve the brightness uniformity of the backlight 100f.

Fig. 3E is a top view of an exemplary backlight 100g. The backlight 100g is similar to the backlight 100e previously described and shown with reference to Fig. 3A and Fig. 3B, except that the elements 107 are arranged at different positions in the backlight 100g and the patterned diffuser 108g is used instead of the patterned diffuser 108e. The patterned diffuser 108g includes a plurality of patterned reflectors 112 and 112g located above the plurality of light sources 106 and the plurality of elements 107. The plurality of patterned reflectors 112 and 112g include an asymmetric reflector 112g located above the corresponding light sources 106 arranged adjacent to the corresponding elements 107, and a symmetric reflector 112 located above the corresponding light sources 106 not arranged adjacent to the corresponding elements 107.

In this embodiment, four patterned reflectors 112g are adjacent to each element 107, such that the element 107 is equidistant from each of the four patterned reflectors 112g. Each patterned reflector 112g is circular minus a missing portion facing the element 107, such that the circular portion of the carrier 110 directly above each element 107 does not include material of the patterned reflector. The asymmetric patterned reflectors 112g adjacent to the corresponding element 107 mitigate the effects caused by the absorptive element 107 to improve the brightness uniformity of the backlight 100g.

4A-4D are multiple views of yet another exemplary backlight including a patterned diffuser. FIG. 4A is a simplified cross-sectional view of an exemplary backlight 200a, and FIG. 4B is a top view of an exemplary backlight 200a. Backlight 200a may include a substrate 102, a reflective layer 104, a plurality of light sources 106, and a patterned diffuser 208a. Patterned diffuser 208a includes a carrier 110 (e.g., a light guide plate) and a plurality of patterned reflectors 212a. A plurality of light sources 106 are adjacent to substrate 102 (e.g., disposed on substrate 102) and are electrically connected to substrate 102. Reflective layer 104 is on substrate 102 and surrounds each light source 106. In some exemplary embodiments, substrate 102 may be reflective, so that reflective layer 104 may not be included. The patterned diffuser 208a is located above the plurality of light sources 106 and optically coupled to each of the light sources 106. In certain exemplary embodiments, the plurality of light sources 106 may be coupled to the patterned diffuser 208a using an optical adhesive (not shown). The refractive index of the optical adhesive (e.g., phenyl silicone) may be greater than or equal to the refractive index of the carrier 110. A plurality of patterned reflectors 212a are disposed on the upper surface of the carrier 110. In other embodiments, the plurality of patterned reflectors 212a may be disposed on the lower surface of the carrier 110. Each patterned reflector 212a is located above a corresponding light source 106. In this embodiment, as shown at 230, the center of each patterned reflector 212a is aligned with the corresponding light source 106 (e.g., the center of the corresponding light source).

Each patterned reflector 212a has a varying transmittance and may have a thickness profile along the width or diameter of the patterned reflector, the thickness profile including a substantially flat portion as shown in 213, a curved portion extending from and surrounding the substantially flat portion 213 as shown in 214, and a corner portion 215 located at each boundary of adjacent patterned reflectors 212a. The substantially flat portion 213 may have a rough surface profile (e.g., the thickness of the entire substantially flat portion varies slightly). In certain exemplary embodiments, the thickness of the substantially flat portion 213 varies by no more than plus or minus 20% of the average thickness of the substantially flat portion. In this embodiment, the average thickness measured in a direction perpendicular to the carrier 110 is defined as the maximum thickness (T _max ) of the substantially flat portion plus the minimum thickness (T _min ) of the substantially flat portion divided by 2 (i.e., (T _max +T _min )/2). For example, for an average thickness of the substantially flat portion 213 of about 100 microns, the maximum thickness of the substantially flat portion may be equal to or less than about 120 microns, and the minimum thickness of the substantially flat portion may be equal to or greater than about 80 microns. In other embodiments, the thickness of the substantially flat portion 213 varies by no more than plus or minus 15% of the average thickness of the substantially flat portion. For example, for an average thickness of the substantially flat portion 213 of about 80 microns, the maximum thickness of the substantially flat portion may be equal to or less than about 92 microns, and the minimum thickness of the substantially flat portion may be equal to or greater than about 68 microns.

In other embodiments, the thickness of the substantially flat portion 213 varies by no more than plus or minus 10% of the average thickness of the substantially flat portion. For example, for an average thickness of the substantially flat portion 213 of about 50 microns, the maximum thickness of the substantially flat portion may be equal to or less than about 55 microns, and the minimum thickness of the substantially flat portion may be equal to or greater than about 45 microns. In other embodiments, the thickness of the substantially flat portion 213 varies by no more than plus or minus 5% of the average thickness of the substantially flat portion. The curved portion 214 may be defined by an absolute ratio of the thickness variation to the distance variation from the center of the patterned reflector 212a. The slope of the curved portion 214 may decrease with the distance from the center of the patterned reflector 212a. In certain exemplary embodiments, the slope is highest near the substantially flat portion 213, decreases rapidly as it moves away from the center of the patterned reflector 212a, and then decreases slowly as it moves further away from the center of the patterned reflector. The corner portion 215 may include a curved portion having a slope that increases with distance from the center of the patterned reflector 212a and then reaches a substantially flat portion at a boundary of adjacent patterned reflectors 212a. The substantially flat portion of the corner portion 215 may have substantially the same thickness or area coverage as the substantially flat portion 213, or the thickness or area coverage of the substantially flat portion of the corner portion 215 may be less than the thickness or area coverage of the substantially flat portion 213.

The dimension L0 (i.e., width or diameter) of each substantially flat portion 213 as indicated at 220 (in a plane parallel to the substrate 102) may be greater than the dimension (i.e., width or diameter) of each corresponding light source 106 as indicated at 124 (in a plane parallel to the substrate 102). The dimension 220 of each substantially flat portion 213 may be less than the dimension 124 of each corresponding light source 106 multiplied by a predetermined value. In certain exemplary embodiments, when the dimension 124 of each light source 106 is greater than or equal to about 0.5 mm, the predetermined value may be about 2 or 3, such that the dimension of each substantially flat portion 213 is less than three times the dimension of each light source 106. When the size 124 of each light source 106 is less than 0.5 mm, the predetermined value may be determined based on the alignment capability between the light source 106 and the patterned reflector 212 a, so that the size of each substantially flat portion 213 of each patterned reflector 212 a is in the range of about 100 μm to about 300 μm larger than the size of each light source 106. Each substantially flat portion 213 is large enough to allow each patterned reflector 212 a to be aligned with the corresponding light source 106, and small enough to achieve appropriate brightness uniformity and color uniformity.

222 represents the dimension L1 (i.e., width or diameter) of the combined curved portion 214 and substantially flat portion of each patterned reflector 212a (in a plane parallel to the substrate 102). 223 represents the dimension L2 (i.e., width or diameter) of each patterned reflector 212a (in a plane parallel to the substrate 102). 126 represents the spacing P between adjacent light sources 106. Although the spacing is illustrated along one direction in FIG. 4A, the spacing may be different in a direction orthogonal to the illustrated direction. The spacing may be, for example, about 90, 45, 30, 10, 5, 2, 1, or 0.5 mm, greater than about 90 mm, or less than about 0.5 mm. In certain exemplary embodiments, the ratio L1/P of the size 222 of each patterned reflector 212a to the spacing 126 is in the range of about 0.45 to 0.9. The ratio can vary with the spacing 126 of the light sources 106 and the distance between the emitting surface of each light source and the corresponding patterned reflector 212a. For example, for a spacing 126 of about 5 mm and a distance of about 0.2 mm between the emitting surface of each light source and the corresponding patterned reflector, the ratio can be equal to about 0.50, 0.60, 0.70, 0.80 or 0.90. The ratio L2/P of the size 223 of each patterned reflector 212a to the spacing 126 is 1.0.

Therefore, as shown in 226 in FIG. 4B , the reflectivity of each patterned reflector 212 a changes from a first value at a first position to a second value at a second position (e.g., 231) less than the first value, and changes from the second value at the second position to a third value at a third position (e.g., 232) greater than the second value, the first position being located at the center (e.g., 230) of each patterned reflector 212 a, the second position being a first distance from the first position, and the third position being a second distance from the first position, the second distance being greater than the first distance. In some exemplary embodiments, the third value is equal to the first value. The third position of each patterned reflector 212 a is adjacent to the intersection of the patterned reflector 212 a and at least two (e.g., three) adjacent patterned reflectors 212 a.

Each patterned reflector 212a reflects at least a portion of the light emitted by the corresponding light source 106 into the carrier 110. Each patterned reflector 212a has specular reflection and diffuse reflection. The specular reflected light is emitted from the bottom surface of the carrier 110. Although the specular reflected light mainly travels laterally due to reflection between the reflective layer 104 and the carrier 110, or due to reflection between the reflective layer 104 and the color conversion layer, diffuser or diffuser plate (as shown in Figure 2), some light loss may occur due to incomplete reflection of the reflective layer 104. The diffusely reflected light has an angular distribution of 0 degrees to 90 degrees measured relative to the normal of the carrier 110. About 50% of the diffusely reflected light has an angle greater than the critical angle of total internal reflection ( ). Therefore, the diffusely reflected light travels laterally due to total internal reflection without any loss until the light is subsequently guided out of the carrier 110 using the patterned reflector 212a.

Compared with the backlight in which the patterned reflector does not include the corner portion 215, the corner portion 215 of each patterned reflector 212a can improve the brightness uniformity of the backlight 200a. The corner portion 215 locally enhances the extraction of light and increases the brightness of the backlight 200a. At the center of each light source area, the patterned glass diffuser 208a reflects back most of the light directly from the light source 106 and generates total internal reflection light. The total internal reflection light travels horizontally in the carrier 110 and is extracted at the corner of the light source area. However, as the distance from the light source 106 increases, the total internal reflection light intensity decreases. In order to reduce this effect, the corner feature structure 215 is used to improve the extraction efficiency of light at the corner of the light source area. The distance ( _LD ) from the center of the light source 106, beyond which the corner feature 215 is preferably located, depends on a number of factors, including the size 124 of each light source 106, the spacing 126 between the light sources 106, and the optical distance (OD) between the light sources 106 and the patterned glass diffuser 208a. For small light sources 106 (e.g., less than about 0.5 mm) and negligible OD (e.g., less than about 1 mm), the _LD can be greater than about 3 mm. If the OD is not negligible (e.g., greater than about 1 mm), the _LD can be equal to about 3+OD/2 mm. If the spacing 126 is less than twice the _LD , the corner portion 215 may not be needed. In addition, if the OD is large enough, the corner portion 215 may not be needed because a larger OD improves brightness uniformity. In certain exemplary embodiments, the corner portion 215 is beneficial when the ratio of the light source spacing to the OD is at least 2. The corner portion 215 can be printed with the same ink as the central pattern of each patterned reflector 212a, or the corner portion 215 can be printed separately with a different ink. The ink of the corner portion 215 can be a white ink or a transparent ink. The area coverage of the corner portion 215 can be about 50% or more to enhance the extraction of light. The corner portion 215 can be formed using any suitable process, such as inkjet printing, screen printing, micro-printing, etc.

FIG. 4C is a top view of an exemplary backlight 200B. Backlight 200b is similar to the backlight 200a previously described and shown with reference to FIG. 4A and FIG. 4B, except that backlight 200b includes a patterned diffuser 208b instead of patterned diffuser 208a. Patterned diffuser 208b includes a carrier 110 (e.g., a light guide plate) and a plurality of patterned reflectors 212b. A plurality of patterned reflectors 212b are arranged on the upper surface of carrier 110. In other embodiments, a plurality of patterned reflectors 212b may be arranged on the lower surface of carrier 110. Each patterned reflector 212b is located above a corresponding light source 106. In this embodiment, the center of each patterned reflector 212b is aligned with a corresponding light source 106 (e.g., the center of the corresponding light source).

In this embodiment, each patterned reflector 212b is similar to each patterned reflector 212a, except that the patterned reflector 212b includes a rectangular feature structure 240 instead of a corner feature structure 215. Each rectangular feature structure 240 is adjacent to (e.g., directly adjacent to) the intersection of the patterned reflector 212b with the adjacent patterned reflector 212b. Each patterned reflector 212b may include two rectangular feature structures 240 located on opposite sides of the circular center pattern of each patterned reflector. As shown in 242 in FIG. 4C , the reflectivity of each patterned reflector 212 b changes from a first value at a first position to a second value at a second position (e.g., 243) that is less than the first value, and changes from the second value at the second position to a third value at a third position (e.g., 244) that is greater than the second value, the first position being located at the center (e.g., 230) of each patterned reflector 212 b, the second position being a first distance from the first position, and the third position being a second distance from the first position, the second distance being greater than the first distance. In some exemplary embodiments, the third value is equal to the first value. In other embodiments, the third value is less than the first value. The third position of each patterned reflector 212 b is adjacent to the intersection of the patterned reflector 212 b and at least one adjacent patterned reflector 212 b. The rectangular features 240 locally enhance light extraction and increase the brightness of the backlight 200b.

FIG. 4D is a top view of an exemplary backlight 200c. Backlight 200c is similar to the backlight 200a previously described and shown with reference to FIG. 4A and FIG. 4B, except that backlight 200c includes a patterned diffuser 208c instead of patterned diffuser 208a. Patterned diffuser 208c includes a carrier 110 (e.g., a light guide plate) and a plurality of patterned reflectors 212c. A plurality of patterned reflectors 212c are arranged on the upper surface of carrier 110. In other embodiments, a plurality of patterned reflectors 212c may be arranged on the lower surface of carrier 110. Each patterned reflector 212c is located above a corresponding light source 106. In this embodiment, the center of each patterned reflector 212c is aligned with a corresponding light source 106 (e.g., the center of the corresponding light source).

In this embodiment, each patterned reflector 212c is similar to each patterned reflector 212a, except that patterned reflector 212c includes rectangular feature structures 240 and 250 in addition to corner feature structure 215. Each rectangular feature structure 240 and 250 is adjacent to (e.g., directly adjacent to) the intersection of patterned reflector 212c with adjacent patterned reflector 212c. Each patterned reflector 212c may include two rectangular feature structures 240 located on first opposite sides of the circular center pattern of each patterned reflector and two rectangular feature structures 250 located on second opposite sides of the circular center pattern of each patterned reflector. In some exemplary embodiments, the rectangular feature structures 240, the rectangular feature structures 250, and/or the corner feature structures 215 may have the same transmittance. In other embodiments, the rectangular feature structures 240, the rectangular feature structures 250, and/or the corner feature structures 215 may have different transmittances. As shown by 242 in FIG. 4D, the reflectivity of each patterned reflector 212c changes from a first value at a first position to a second value at a second position (e.g., 243) that is less than the first value, and changes from the second value at the second position to a third value at a third position (e.g., 244) that is greater than the second value, the first position being located at the center (e.g., 230) of each patterned reflector 212c, the second position being a first distance from the first position, and the third position being a second distance from the first position, the second distance being greater than the first distance. In some exemplary embodiments, the third value is equal to the first value. In other embodiments, the third value is less than the first value. The third position of each patterned reflector 212c is adjacent to an intersection of the patterned reflector 212c and at least one adjacent patterned reflector 212c.

As shown in 252, the reflectivity of each patterned reflector further changes from a first value at a first position (e.g., 230) to a second value at a fourth position (e.g., 253), and from the second value at the fourth position to a fourth value at a fifth position (e.g., 254), wherein the fourth position is a first distance from the first position, the fifth position is a third distance from the first position, the third distance is greater than the second distance, and the fourth value is greater than the second value and less than the third value. The third position of each patterned reflector 212c includes a first rectangular feature structure 240, which includes a first rectangular area adjacent to the intersection of the patterned reflector 212c and the adjacent patterned reflector 212c, and the fifth position of each patterned reflector 212c includes a second rectangular feature structure 250, which includes a second rectangular area perpendicular to the first rectangular area and adjacent to the intersection of the patterned reflector 212c and another adjacent patterned reflector 212c. The rectangular feature structures 240 and 250 and the corner feature structure 215 locally enhance the extraction of light and increase the brightness of the backlight 200c.

5 is a graph 300 showing an exemplary relationship of thickness/area coverage versus radial position for a patterned reflector (e.g., patterned reflector 212a, 212b, or 212c of FIGS. 4A to 4D) of a patterned diffuser. In one embodiment, as shown by curve 302, as the distance from the center of the patterned reflector increases, the thickness/area coverage substantially maintains a maximum value, then the thickness/area coverage decreases to a minimum value, substantially maintains the minimum value, then increases back to a maximum value, and substantially maintains the maximum value. In another embodiment, as shown by curve 304, as the distance from the center of the patterned reflector increases, the thickness/area coverage ratio substantially maintains a maximum value, then the thickness/area coverage ratio decreases to a minimum value, substantially maintains the minimum value, then increases back to a value between the minimum value and the maximum value, and substantially maintains a value between the minimum value and the maximum value.

For the patterned reflector 212a of Figure 4B, the radial position of the graph 300 may correspond to from the center of the patterned reflector 212a to the corner (226) of the patterned reflector 212a. For the patterned reflector 212b of Figure 4C, the radial position of the graph 300 may correspond to from the center of the patterned reflector 212b to a side (242) of the patterned reflector 212b. For the patterned reflector 212c of Figure 4D, the radial position of the graph 300 may correspond to from the center of the patterned reflector 212c to a first side (242) of the patterned reflector 212c, may correspond to from the center of the patterned reflector 212c to a second side (252) of the patterned reflector 212c that is perpendicular to the first side, and/or may correspond to from the center of the patterned reflector 212c to a corner (226) of the patterned reflector 212c.

6A and 6B are simplified cross-sectional and top views of an exemplary backlight 600, respectively. Although not shown in FIGS. 6A and 6B, the backlight 600 may also include a patterned diffuser 108a, 108b, 108c, 108e, 108f, or 108g as previously described with reference to at least FIGS. 1A-1C and 3A-3E. In addition, the backlight 600 may be used in the LCD 150 of FIG. 2 instead of the backlight 100a. The backlight 600 may include a substrate 102, a reflective layer 104, a plurality of light sources 106, a plurality of elements 607, and a backplane 602. The plurality of light sources 106 are adjacent to the substrate 102 (e.g., disposed on the substrate 102) and are electrically connected to the substrate 102. A plurality of elements 607 are adjacent to the substrate 102 (e.g., arranged on and/or through the substrate 102) and can be electrically connected to the substrate 102. In some exemplary embodiments, each element 607 is an electrical contact (e.g., copper, silver) extending through the substrate 102 to electrically couple a plurality of light sources 106 on a first side of the substrate 102 to a backplane 602 on a second side of the substrate 102 opposite to the first side. For example, each element 607 can electrically couple one dimming zone 140 to the backplane 602. The backplane 602 can include circuitry for individually controlling each dimming zone 140 (e.g., on, off, and brightness control). In other embodiments, each element 607 can be a control chip that controls the light source 106 in the corresponding dimming zone 140.

The reflective layer 104 is located on the substrate 102 and surrounds each light source 106 and each element 607. In some exemplary embodiments, the substrate 102 is reflective and thus may not include the reflective layer 104. The reflective layer 104 has a first reflectivity, and each element 607 has a second reflectivity different from the first reflectivity. In some exemplary embodiments, the second reflectivity is less than the first reflectivity.

Referring to the top view of FIG. 6B , the light sources 106 are arranged in a 2D array including a plurality of rows and a plurality of columns. Although FIG. 6B illustrates 36 light sources 106 in six rows and six columns, in other embodiments, the backlight 600 may include any suitable number of light sources 106 arranged in any suitable number of rows and any suitable number of columns. The light sources 106 may also be arranged in other periodic patterns, such as hexagonal or triangular lattices, or in quasi-periodic or non-strict periodic patterns. For example, the spacing between the light sources 106 may be smaller at the edges and/or corners of the backlight 600.

In this embodiment, each dimming zone 140 includes four light sources 106 arranged in a 2×2 arrangement for each element 607. The light sources 106 in a row have a first spacing Px (e.g., center to center) as shown at 142, and the light sources 106 in a column have a second spacing Py (e.g., center to center) as shown at 144. In some exemplary embodiments, the first spacing Px 142 may be different from the second spacing Py 144. In other embodiments, the first spacing Px 142 may be equal to the second spacing Py 144. In the embodiment shown in FIG. 6B, the first spacing Px 142 is less than the second spacing Py 144.

In each dimming zone 140, the element 607 may be adjacent to the corresponding first nearest light source 106 ₁ , the second nearest light source 106 ₂ , the third nearest light source 106 ₃ and the fourth nearest light source 106 ₄ . The distances from the first, second, third and fourth nearest light sources to the element 607 may be equal. In certain exemplary embodiments, as shown in 612, the distance d1 between the center of each element 607 and the corresponding first nearest light source 106 ₁ (e.g., the center of the first nearest light source 106 ₁ ) is greater than or equal to the first spacing Px 142 or greater than or equal to the second spacing Py 144. The corresponding center of each of the corresponding first nearest light source 106 ₁ , the second nearest light source 106 ₂ , the third nearest light source 106 ₃ and the fourth nearest light source 106 ₄ is used as a vertex to form a corresponding quadrilateral 610. In some exemplary embodiments, the distance d1 612 between the center of each element 607 and the corresponding first closest light source 106 ₁ (e.g., the center of the first closest light source 106 ₁ ) is at least about 80% of the distance between the center of the corresponding quadrilateral 610 and the corresponding first closest light source 106 _1. In other embodiments, the distance d1 612 between the center of each element 607 and the corresponding first closest light source 106 ₁ (e.g., the center of the first closest light source 106 ₁ ) is at least about 98% of the distance between the center of the corresponding quadrilateral 610 and the corresponding first closest light source 106 ₁ .

In other embodiments, the distance d1 612 between the center of the element 607 and the nearest light source ₁₀₆₁ is provided by: In other embodiments, the distance d1 612 between the center of the element 607 and the nearest light source ₁₀₆₁ is provided by: In other embodiments, the distance d1 612 between the center of the element 607 and the nearest light source ₁₀₆₁ is provided by: In other embodiments, the distance d1 612 between the center of the element 607 and the nearest light source ₁₀₆₁ is provided by:

A patterned diffuser including a plurality of patterned reflectors and a plurality of compensating features may be located above a plurality of light sources 106 and elements 607 within each dimming zone 140. Each patterned reflector may be located above a corresponding light source 106 and may have a varying transmittance. Each compensating feature may be located above a corresponding element 607. Each element 607 may locally reduce brightness around the area where each element is located, which may result in mura that affects brightness uniformity. However, the farther the element 607 is positioned from the nearest light source, the less light the element 607 absorbs. By placing each element 607 farther from the light sources 106 ₁ , 106 ₂ , 106 ₃ , and 106 ₄ within each dimming zone 140 (eg, at the maximum possible distance from the nearest light source), the backlight 600 can have higher brightness and improved alignment tolerance with the patterned diffuser.

FIG. 7A is a top view of an exemplary dimming zone 140a of a backlight (e.g., backlight 600 of FIG. 6A and FIG. 6B ). Backlight 600 may include a plurality of dimming zones 140a arranged in rows and columns. Dimming zone 140a includes element 607 and four light sources 106, including a first nearest light source 106 ₁ , a second nearest light source 106 ₂ , a third nearest light source 106 ₃ , and a fourth nearest light source 106 ₄ arranged in two rows and two columns. Light sources 106 in a row (e.g., 106 ₃ and 106 ₄ ) have a first spacing Px (e.g., center to center) as shown in 142a, and light sources 106 in a column (e.g., 106 ₁ and 106 ₃ ) have a second spacing Py (e.g., center to center) as shown in 144a. In some exemplary embodiments, the first pitch Px 142a may be different from the second pitch Py 144a. In other embodiments, the first pitch Px 142a may be equal to the second pitch Py 144a. In the embodiment shown in FIG. 7A, the first pitch Px 142a is smaller than the second pitch Py 144a.

The centers 706 ₁ , 706 ₂ , 706 ₃ and 706 ₄ of each of the first closest light source 106 ₁ , the second closest light source 106 ₂ , the third closest light source 106 ₃ and the fourth closest light source 106 ₄ are respectively used as vertices to form a quadrilateral 610 a. In this embodiment, the center 707 of the element 607 within the dimming zone 140 a is arranged at the center 710 a of the quadrilateral 610 a, so that the distance 612 a between the center 707 of the element 607 and the first closest light source 106 ₁ (e.g., the center 706 ₁ of the first closest light source 106 ₁ ) is about 100% of the distance between the center 710 a of the quadrilateral 610 a and the first closest light source 106 _1. Therefore, the element 607 is arranged at the maximum possible distance from the closest light source. In this embodiment, the plurality of light sources 106 ₁ , 106 ₂ , 106 ₃ , and 106 ₄ within each dimming zone 140 a are aligned with respect to a rectangular grid such that the quadrilateral 610 a is a rectangle.

FIG. 7B is a top view of an exemplary dimming zone 140 b of a backlight (e.g., backlight 600 of FIGS. 6A and 6B ). Backlight 600 may include a plurality of dimming zones 140 b arranged in rows and columns. Dimming zone 140 b includes element 607 and four light sources 106, including a first light source 106 ₁ , a second light source 106 ₂ , a third light source 106 3 , and a fourth light source 106 ₄ arranged in two rows and two columns. The light sources 106 in a row (e.g., _{106 3 and} 106 ₄ ) have a first spacing Px (e.g., center to center) as shown in 142 b, and the light sources 106 in a column (e.g., 106 ₁ and 106 ₃ ) have a second spacing Py (e.g., center to center) as shown in 144 b. In some exemplary embodiments, the first pitch Px 142b may be different from the second pitch Py 144b. In other embodiments, the first pitch Px 142b may be equal to the second pitch Py 144b. In the embodiment shown in FIG. 7B, the first pitch Px 142b is smaller than the second pitch Py 144b.

The centers 706 ₁ , 706 ₂ , 706 ₃ and 706 ₄ of each of the first light source 106 ₁ , the second light source 106 ₂ , the third light source 106 ₃ and the fourth light source 106 ₄ are respectively used as vertices to form a quadrilateral 610 b. In this embodiment, the center 707 of the element 607 within the dimming zone 140 b is arranged at a corner of the dimming zone 140 b, so that the distance 612 b between the center 707 of the element 607 and the first nearest light source 106 ₁ (e.g., the center 706 ₁ of the first nearest light source 106 ₁ ) is the maximum possible distance between the center 707 of the element 607 and the nearest light source (the light source 106 ₁ in this embodiment). For example, the distance 612b may be greater than the distance between the center 710b of the quadrilateral 610b and the center ₇₀₆₁ of the first light source _1061. In this embodiment, the plurality of light sources ₁₀₆₁ , ₁₀₆₂ , ₁₀₆₃ and ₁₀₆₄ within each dimming zone 140b are aligned relative to a rectangular grid such that the quadrilateral 610b is rectangular.

FIG. 7C is a top view of an exemplary dimming zone 140 c of a backlight (e.g., backlight 600 of FIGS. 6A and 6B ). Backlight 600 may include a plurality of dimming zones 140 c arranged in rows and columns. Dimming zone 140 c includes element 607 and four light sources 106, including a first nearest light source 106 ₁ , a second nearest light source 106 ₂ , a third nearest light source 106 3 , and a fourth nearest light source 106 ₄ arranged in a 2×2 array. Light sources 106 in a row (e.g., _{106 3 and} 106 ₄ ) have a first spacing Px (e.g., center to center) as shown in 142 c, and light sources 106 in a column (e.g., 106 ₁ and 106 ₃ ) have a second spacing Py (e.g., center to center) as shown in 144 c. In some exemplary embodiments, the first pitch Px 142c may be different from the second pitch Py 144c. In other embodiments, the first pitch Px 142c may be equal to the second pitch Py 144c. In the embodiment shown in FIG. 7C, the first pitch Px 142c is smaller than the second pitch Py 144c.

The centers 706 ₁ , 706 ₂ , 706 ₃ and 706 ₄ of each of the first closest light source 106 ₁ , the second closest light source 106 ₂ , the third closest light source 106 ₃ and the fourth closest light source 106 ₄ are respectively used as vertices to form a quadrilateral 610 c. In this embodiment, the center 707 of the element 607 within the dimming zone 140 c is arranged at the center 710 c of the quadrilateral 610 c, so that the distance 612 c between the center 707 of the element 607 and the first closest light source 106 ₁ (e.g., the center 706 ₁ of the first closest light source 106 ₁ ) is about 100% of the distance between the center 710 c of the quadrilateral 610 c and the first closest light source 106 _1. Therefore, the element 607 is arranged at the maximum possible distance from the closest light source. In this embodiment, the plurality of light sources 106 ₁ , 106 ₂ , 106 ₃ , and 106 ₄ within each dimming zone 140 c are offset relative to the rectangular grid such that the quadrilateral 610 c is not a rectangle.

FIG. 7D is a top view of an exemplary dimming zone 140d of a backlight (e.g., backlight 600 of FIGS. 6A and 6B ). Backlight 600 may include a plurality of dimming zones 140d arranged in rows and columns. Dimming zone 140d includes element 607 and six light sources 106, including a first nearest light source 106 ₁ , a second nearest light source 106 ₂ , a third nearest light source 106 3 , a fourth nearest light source 106 ₄ , a fifth light source 106 ₅ , and a sixth light source _{106 6 arranged} in two rows and three columns. The light sources 106 in a row (e.g., 106 ₃ and 106 ₄ ) have a first spacing Px (e.g., center to center) as shown in 142d, and the light sources 106 in a column (e.g., 106 ₁ and 106 ₃ ) have a second spacing Py (e.g., center to center) as shown in 144d. In some exemplary embodiments, the first pitch Px 142d may be different from the second pitch Py 144d. In other embodiments, the first pitch Px 142d may be equal to the second pitch Py 144d. In the embodiment shown in FIG. 7D, the first pitch Px 142d is smaller than the second pitch Py 144d.

The centers 706 ₁ , 706 2 , 706 ₃ and 706 ₄ of each of the first closest light source 106 ₁ , the second closest light source 106 ₂ , the third closest light source 106 ₃ and the _fourth closest light source 106 ₄ of the nearest element 607 are respectively used as vertices to form a quadrilateral 610 d. In this embodiment, the center 707 of the element 607 within the dimming zone 140 d is arranged at the center 710 d of the quadrilateral 610 d, so that the distance 612 d between the center 707 of the element 607 and the first closest light source 106 ₁ (e.g., the center 706 ₁ of the first closest light source 106 ₁ ) is about 100% of the distance between the center 710 d of the quadrilateral 610 d and the first closest light source 106 _1. Therefore, the element 607 is arranged at the maximum possible distance from the nearest light source. In this embodiment, the plurality of light sources 106 ₁ , 106 ₂ , 106 ₃ , 106 ₄ , 106 ₅ , and 106 ₆ within each dimming zone 140 d are aligned with respect to a rectangular grid such that the quadrilateral 610 d is a rectangle.

FIG7E is a top view of an exemplary dimming zone 140e of a backlight (e.g., backlight 600 of FIG6A and FIG6B). Backlight 600 may include a plurality of dimming zones 140e arranged in rows and columns. Dimming zone 140e includes element 607 and nine light sources 106, which include a first nearest light source ₁₀₆₁ , a second nearest light source ₁₀₆₂ , a third nearest light source ₁₀₆₃ , a fourth nearest light source 1064, a fifth light source ₁₀₆₅ , a sixth light source ₁₀₆₆ , a seventh light source ₁₀₆₇ , an eighth light source ₁₀₆₈ , and a ninth light source ₁₀₆₉ arranged in three rows _{and three columns} . The light sources 106 in a row (e.g., 106 ₃ and 106 ₄ ) have a first spacing Px (e.g., center to center) as shown in 142e, and the light sources 106 in a column (e.g., 106 ₁ and 106 ₃ ) have a second spacing Py (e.g., center to center) as shown in 144e. In some exemplary embodiments, the first spacing Px 142e may be different from the second spacing Py 144e. In other embodiments, the first spacing Px 142e may be equal to the second spacing Py 144e. In the embodiment shown in FIG. 7E , the first spacing Px 142e is less than the second spacing Py 144e.

The centers 706 ₁ , 706 2 , 706 ₃ and 706 ₄ of each of the first closest light source 106 ₁ , the second closest light source 106 ₂ , the third closest light source 106 ₃ and the fourth closest light source 106 ₄ of the nearest element ₆₀₇ are respectively used as vertices to form a quadrilateral 610e. In this embodiment, the center 707 of the element 607 within the dimming zone 140e is arranged at the center 710e of the quadrilateral 610e, so that the distance 612e between the center 707 of the element 607 and the first closest light source 106 ₁ (e.g., the center 706 ₁ of the first closest light source 106 ₁ ) is about 100% of the distance between the center 710e of the quadrilateral 610e and the first closest light source 106 _1. Therefore, the element 607 is arranged at the maximum possible distance from the nearest light source. In this embodiment, the plurality of light sources 106 ₁ , 106 ₂ , 106 ₃ , 106 ₄ , 106 ₅ , 106 ₆ , 106 ₇ , 106 ₈ , and 106 ₉ within each dimming zone 140 e are aligned with respect to a rectangular grid such that the quadrilateral 610 e is a rectangle.

It is obvious to those skilled in the art that various modifications and variations can be made to the embodiments of the present invention without departing from the spirit and scope of the present invention. Therefore, the present invention is intended to cover these modifications and variations as long as they fall within the scope of the attached claims and their equivalents.

102: substrate 104: reflective layer 106: light source 107: element 110: carrier 112: patterned reflector 113: substantially flat portion 114: curved portion 120: size 122: size 124: size 126: spacing 130: alignment 132: alignment 134: offset 136: offset 140: dimming zone 142: first spacing 144: second spacing 146: distance 150: liquid crystal display 152: diffuser 154: color conversion layer 156: prism film 158: reflective polarizer 160: display panel 170: center of the first light source Center 172: Center of corresponding element 174: Distance 176: Distance 213: Basic flat portion 214: Curved portion 215: Corner portion 220: Dimension 222: Dimension 223: Dimension 240: Rectangular feature structure 250: Rectangular feature structure 300: Graph 302: Curve 304: Curve 600: Backlight 602: Backplane 607: Element 610: Quad 612: Distance 707: Center 100a: Backlight 100b: Backlight 100c: Backlight 100d: Backlight 100e: Backlight 100f: Backlight 100g: Backlight 106 ₁ : first closest light source 106 ₂ : second closest light source 106 ₃ : third closest light source 106 ₄ : fourth closest light source 106 ₅ : fifth light source 106 ₆ : sixth light source 106 ₇ : seventh light source 106 ₈ : eighth light source 106 ₉ : : Ninth light source 108a: Patterned diffuser 108b: Patterned diffuser 108c: Patterned diffuser 108e: Patterned diffuser 108f: Patterned diffuser 108g: Patterned diffuser 112a: Patterned reflector 112b: Patterned reflector 112c: Patterned reflector 112d: Patterned reflector 112e: Patterned reflector 112f: Patterned reflector 112g: Patterned reflector 118a: Compensation feature structure 118b: Compensation feature structure 118c: Compensation feature structure 140: Dimming zone 140a: Dimming zone 140b: Dimming zone 140c: Dimming zone 140d: Dimming zone 140e: Dimming zone 142a: First spacing Px 142b: first distance Px 142c: first distance Px 142d: first distance Px 142e: first distance Px 144a: second distance Py 144b: second distance Py 144c: second distance Py 144d: second distance Py 200a: backlight 200c: backlight 208a: patterned diffuser 208b: patterned diffuser 208c: patterned diffuser 212a: patterned reflector 212b: patterned reflector 212c: patterned reflector 610a: quadrilateral 610b: quadrilateral 610c: quadrilateral 610d: quadrilateral 610e: quadrilateral 612a: distance 612b: distance 612d: distance 612e: distance 706 ₁ -706 ₄ : Center 710a : Center 710b : Center 710c : Center 710d : Center 710e : Center

1A-1F are various views of an exemplary backlight including a patterned diffuser;

FIG. 2 is a simplified cross-sectional view of an exemplary liquid crystal display (LCD) including the exemplary backlight of FIG. 1A ;

3A-3E are various views of other exemplary backlights including patterned diffusers;

4A-4D are various views of yet another exemplary backlight including a patterned diffuser;

FIG5 is a graph illustrating an exemplary relationship of thickness/area coverage of a patterned reflector versus radial position for a patterned diffuser;

6A and 6B are simplified cross-sectional and top views, respectively, of another exemplary backlight;

7A-7E are top views of exemplary dimming zones of a backlight.

Domestic storage information (please note in the order of storage institution, date, and number) None Foreign storage information (please note in the order of storage country, institution, date, and number) None

102: Substrate

104: Reflective layer

106: Light source

107: Components

110: Carrier

112: Patterned reflector

113: basically flat part

114: Surface part

120: Size

122:Size

124:Size

126: Spacing

130: Alignment

132: Alignment

100a: Backlight

108a: Patterned diffuser

112a: Patterned reflector

118a: Compensation feature structure

Claims (25)

A backlight, the backlight comprising: a substrate; a plurality of light sources, the plurality of light sources being adjacent to the substrate; a reflective layer, the reflective layer being located on the substrate, the reflective layer having a first reflectivity; a plurality of elements, the plurality of elements being adjacent to the substrate, each element having a second reflectivity different from the first reflectivity; and a patterned diffuser, the patterned diffuser comprising a plurality of patterned reflectors and a plurality of compensating feature structures located above the plurality of light sources and the plurality of elements, each patterned reflector being located above a corresponding light source and having a varying transmittance, and each compensating feature structure being located above a corresponding element. A backlight as claimed in claim 1, wherein the second reflectivity is less than the first reflectivity. The backlight of claim 1, wherein each compensating feature structure comprises an opening through a patterned reflector. A backlight as claimed in claim 1, wherein a transmittance of each compensation feature structure is different from a transmittance at a corresponding position of each patterned reflector that does not correspond to an element. A backlight as claimed in claim 1, wherein each compensation feature structure has a constant transmittance. A backlight as in claim 1, wherein a transmittance of each compensating feature structure varies from a lower value closer to a center of a patterned reflector to a higher value farther from the center of the patterned reflector. A backlight as in claim 1, wherein a center of each patterned reflector is aligned with a corresponding light source, and a center of each compensation feature structure is aligned with a corresponding element. A backlight as in claim 1, wherein a center of each patterned reflector is offset relative to a corresponding light source, and a center of each compensation feature structure is offset relative to a corresponding element. A backlight comprises: a substrate; a plurality of light sources, the plurality of light sources being adjacent to the substrate; a reflective layer, the reflective layer being located on the substrate and having a first reflectivity; a plurality of elements, the plurality of elements being adjacent to the substrate, each element having a second reflectivity different from the first reflectivity; and a patterned diffuser, the patterned diffuser comprising a plurality of patterned reflectors located above the plurality of light sources and the plurality of elements, wherein the plurality of patterned reflectors comprise an asymmetric reflector located above a corresponding light source arranged adjacent to a corresponding element and a symmetric reflector located above a corresponding light source not arranged adjacent to a corresponding element. A backlight as in claim 9, wherein the second reflectivity is less than the first reflectivity. A backlight as in claim 9, wherein a first asymmetric reflector located on a first side of a corresponding element adjacent to a corresponding first light source has a first area, and a second asymmetric reflector located on a second side of the corresponding element adjacent to a corresponding second light source has a second area. A backlight as in claim 9, wherein a center of each symmetrical reflector is aligned with a corresponding light source. A backlight as in claim 9, wherein a center of each symmetrical reflector is offset relative to a corresponding light source. A backlight comprises: a substrate; a plurality of light sources, the plurality of light sources being adjacent to the substrate; a reflective layer, the reflective layer being located on the substrate; and a patterned diffuser, the patterned diffuser comprising a plurality of patterned reflectors located above the plurality of light sources, each patterned reflector being aligned with a corresponding light source, and a reflectivity of each patterned reflector varying from a first value at a first position to a second value at a second position less than the first value, and varying from the second value at the second position to a third value at a third position greater than the second value, the first position being located at a center of each patterned reflector, the second position being a first distance from the first position, and the third position being a second distance from the first position, the second distance being greater than the first distance. The backlight of claim 14, wherein the third position of each patterned reflector is adjacent to an intersection of the patterned reflector and at least two adjacent patterned reflectors. The backlight of claim 14, wherein the third position of each patterned reflector comprises a rectangular area proximate an intersection of the patterned reflector and an adjacent patterned reflector. A backlight as in claim 14, wherein the reflectivity of each patterned reflector also changes from the first value at the first position to the second value at a fourth position, and from the second value at the fourth position to a fourth value at a fifth position, the fourth position being the first distance from the first position, the fifth position being a third distance from the first position, the third distance being greater than the second distance, and the fourth value being greater than the second value and less than the third value. A backlight comprises: a substrate; a plurality of light sources, the plurality of light sources being adjacent to the substrate; a reflective layer, the reflective layer being located on the substrate and having a first reflectivity; and a plurality of elements, the plurality of elements being adjacent to the substrate, each element being adjacent to a corresponding first nearest light source, a second nearest light source, a third nearest light source and a fourth nearest light source among the plurality of light sources, a corresponding quadrilateral being formed with a corresponding center of each of the corresponding first light source, second light source, third light source and fourth light source as a vertex, each element having a second reflectivity different from the first reflectivity, and a distance between a center of each element and the corresponding first nearest light source being at least about 80% of a distance between a center of the corresponding quadrilateral and the corresponding first nearest light source. A backlight as in claim 18, wherein the distance between the center of each element and the corresponding first nearest light source is at least about 98% of the distance between a center of the corresponding quadrilateral and the corresponding first nearest light source. A backlight as in claim 18, wherein the second reflectivity is less than the first reflectivity. The backlight of claim 18 further comprises: A patterned diffuser, the patterned diffuser comprising a plurality of patterned reflectors and a plurality of compensating feature structures located above the plurality of light sources and the plurality of elements, each patterned reflector being located above a corresponding light source and having a varying transmittance, and each compensating feature structure being located above a corresponding element. A backlight comprises: a substrate; a plurality of dimming zones, each of which comprises a plurality of light sources adjacent to the substrate and comprises a first spacing Px and a second spacing Py between the plurality of light sources; a reflective layer located on the substrate, the reflective layer having a first reflectivity; and an element located in each dimming zone adjacent to the substrate, the element having a second reflectivity different from the first reflectivity, and a distance d1 between a center of the element and a nearest light source among the plurality of light sources is provided by the following formula: . The backlight of claim 22, wherein the distance d1 between the center of the element and the nearest light source is provided by: . A backlight as in claim 22, wherein the second reflectivity is less than the first reflectivity. The backlight of claim 22 further comprises: A patterned diffuser, the patterned diffuser comprising the plurality of light sources in each dimming zone and a plurality of patterned reflectors and a plurality of compensating feature structures above the element, each patterned reflector being located above a corresponding light source and having a varying transmittance, and each compensating feature structure being located above a corresponding element.