KR102172907B1 - Displays with direct backlight units - Google Patents

Abstract

The array of pixels in the display can be illuminated by a backlight having an array of light emitting diodes in each array of cells. A reflector is used to reflect light from light emitting diodes through an array of pixels. Within the cells, the reflector has cross-sectional profiles that help to disperse the light emitted from the light emitting diodes towards the edges of the cells. The light diffuser layer for the backlight may have a partially reflective layer, such as a thin film interference filter with angle dependent transmission. Within each cell, the reflector can have cross-sectional profiles with parts that are parabolic or elliptical.

Description

Displays with direct backlight units

This application is filed on January 29, 2018, PCT Patent Application No. PCT/US18/15776, filed on November 21, 2017, which is incorporated herein by reference in its entirety. 819,085, and U.S. Provisional Patent Application No. 62/466,492, filed March 3, 2017.

The present application relates generally to displays, and more particularly to backlight displays.

Electronic devices often include displays. For example, computers and cellular telephones are sometimes provided with backlit liquid crystal displays. Edge-lit backlight units have light emitting diodes that emit light into the edge surface of the light guide plate. Then, the light guide plate serves as a backlight illumination by dispersing the emitted light laterally across the display. Direct-lit backlight units have arrays of light emitting diodes that emit light vertically through the display.

Direct backlights may have locally dimmable light emitting diodes that allow for improved dynamic range. However, if care is not taken, direct backlights can become bulky or create non-uniform backlight illumination.

The display may have a pixel array such as a liquid crystal pixel array. The pixel array can be illuminated with backlight illumination from the backlight unit. The backlight unit may include an array of light emitting diodes and a light reflector that assists in reflecting light from the light emitting diodes through the pixel array. Each light emitting diode may be located in a respective cell. In each cell, the light reflector may have a cross-sectional profile comprising a parabolic or elliptical portion.

A diffuser in the display can be used to homogenize the light from the array of light emitting diodes. The phosphorescent layer and other optical films can be overlaid with the diffuser.

The light emitting diodes may be blue light emitting diodes. The partially reflective layer may be interposed between the diffuser and the array of light emitting diodes. The partially reflective layer can be formed as a stack of dielectric layers on the diffuser. The stack of dielectric layers can form a thin film interference filter with angle dependent transmission.

Light-emitting diodes may be mounted on a printed circuit and protrude through openings in the light reflector. The light reflector may be formed of a reflective material such as a reflective white layer or a dielectric stack forming a thin film interference mirror.

1 is a diagram of an exemplary electronic device with a display, according to one embodiment.
2 is a cross-sectional side view of an exemplary display, according to an embodiment.
3 is a plan view of an exemplary light emitting diode array for a direct type backlight unit, according to an exemplary embodiment.
4 is a cross-sectional side view of an exemplary light emitting diode, according to an embodiment.
5 is a cross-sectional side view of an exemplary light emitting diode in a cavity reflector showing how light can be emitted from the light emitting diode at various angles, according to one embodiment.
6 is a graph showing how the light emitting diodes and the reflective layer of FIG. 5 can be overlapped by a layer having a variable angle light transmittance according to an exemplary embodiment.
7 and 8 are perspective views of cavity reflector cells for a backlight unit according to embodiments.
9 is a plan view of a portion of a backlight unit according to an exemplary embodiment.
10 is a cross-sectional side view of an exemplary cavity reflector of the type shown in FIG. 7, according to one embodiment.
11 is a cross-sectional side view of an exemplary cavity reflector of the type shown in FIG. 8, according to one embodiment.
12 is a cross-sectional diagram of an exemplary cavity reflector including a portion having an elliptical profile, according to one embodiment.
13 is a cross-sectional diagram of an exemplary cavity reflector including a portion having a parabolic profile, according to one embodiment.
14 is a cross-sectional side view of an exemplary stack of dielectric layers, such as alternating refractive index dielectric layers forming a thin film interference filter, in accordance with one embodiment.
15 is a cross-sectional side view of an exemplary light-collimating layer, such as a prism film, in accordance with one embodiment.
16 is a cross-sectional side view of an exemplary microlens array layer, according to one embodiment.
17 is a cross-sectional side view of an exemplary diffuser layer, according to one embodiment.
18 is a cross-sectional side view of an exemplary display, according to one embodiment.

Backlit displays can be provided in electronic devices. Backlight displays may include liquid crystal pixel arrays or other display structures that are backlit by light from a direct backlight unit. A perspective view of an exemplary electronic device of the type in which a display with a direct backlight unit may be provided is shown in FIG. 1. The electronic device 10 of FIG. 1 is a computing device such as a laptop computer, a computer monitor including an embedded computer, a tablet computer, a cellular phone, a media player, or other handheld or portable electronic device, a smaller device, such as a wrist. -Embedded devices in watch devices, pendant devices, headphones or earpiece devices, glasses or other equipment worn on the user's head, or other wearable or small devices, televisions, computer displays that do not include embedded computers, gaming The device, navigation device, electronic equipment having a display may be an embedded system such as a kiosk or a system mounted in an automobile, equipment that implements the functions of two or more of these devices, or other electronic equipment.

As shown in FIG. 1, device 10 may have a display such as display 14. The display 14 may be mounted within the housing 12. Housing 12, sometimes referred to as an enclosure or case, is plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or any two of these materials. It can be formed in a combination of the above. The housing 12 may be formed using an integral configuration in which some or all of the housing 12 are machined or molded as a single structure, or may be formed using a plurality of structures (e.g., an inner frame structure, One or more structures, etc.).

The housing 12 may have a stand, such as the optional stand 18, and have multiple parts (e.g., parts of the housing that move relative to each other to form a laptop computer or other device with moving parts). May be in the shape of a cellular telephone or tablet computer (eg, in arrangements where the stand 18 is omitted), and/or may have other suitable configurations. The arrangement for the housing 12 shown in FIG. 1 is exemplary.

Display 14 includes a layer of conductive capacitive touch sensor electrodes or other touch sensor components (eg, resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components). Etc.), or it may be a non-touch-sensitive display. Capacitive touch screen electrodes can be formed of an array of indium tin oxide pads or other transparent conductive structures.

Display 14 may include an array of pixels 16 formed of liquid crystal display (LCD) components, or may have an array of pixels based on other display technologies. A cross-sectional side view of the display 14 is shown in FIG. 2.

As shown in FIG. 2, the display 14 may include a pixel array such as a pixel array 24. The pixel array 24 may comprise an array of pixels such as the pixels 16 of FIG. 1 (eg, an array of pixels having rows and columns of pixels 16). The pixel array 24 may be formed of a liquid crystal display module (sometimes referred to as a liquid crystal display or liquid crystal layers) or other suitable pixel array structures. The liquid crystal display forming the pixel array 24 includes, for example, upper and lower polarizers, a color filter layer and a thin film transistor layer interposed between the upper and lower polarizers, and a color filter layer and a thin film transistor layer. It may include a layer of liquid crystal material. If desired, other types of liquid crystal display structures may be used to form the pixel array 24.

During operation 14, images may be displayed on the pixel array 24. The backlight unit 42 (sometimes referred to as a backlight, backlight layers, backlight structures, backlight module, backlight system, etc.) can be used to create the backlight illumination 44 passing through the pixel array 24. This illuminates any images on the pixel array 24 viewed by an observer, such as an observer 20 viewing the display 14 in a direction 22.

The backlight unit 42 may have optical films 26, a light diffuser such as a light diffuser (light diffuser layer) 34, and a light emitting diode array 36. Light-emitting diode array 36 may include a two-dimensional array of light sources such as light-emitting diodes 38 that generate backlight illumination 44. The light emitting diodes 38 may be arranged in rows and columns, for example, and lie within the X-Y plane of FIG. 2.

The light emitting diodes 38 may be controlled in unison by the control circuitry within the device 10, or may be individually controlled (e.g., localized to help improve the dynamic range of images displayed on the pixel array 24). To implement a local dimming scheme). The light generated by each light emitting diode 38 can travel upward along dimension Z through the light diffuser 34 and optical films 26 before passing through the pixel array 24. The light diffuser 34 may include light-scattering structures that help diffuse light from the light emitting diode array 36 and thereby provide a uniform backlight illumination 44. The optical films 26 may include films, such as a dichroic filter 32, a phosphor layer 30, and films 28. Films 28 are brightness enhancing films and/or other optical films (e.g., compensation films) that collimate light 44 and thereby help improve the brightness of display 14 for user 20. And the like).

The light-emitting diodes 38 can emit light of any suitable color. In one exemplary configuration, the light emitting diodes 38 emit blue light. The dichroic filter layer 32 may be configured to reflect light of different colors while passing blue light from the light emitting diodes 38. The blue light from the light-emitting diodes 38 is converted to white light by a photoluminescent material such as a phosphor layer 30 (e.g., a layer of a white phosphor material or other photoluminescent material that converts blue light to white light). Can be converted. If desired, other photoluminescent materials may be used to convert blue light into different colors of light (eg, red light, green light, white light, etc.). For example, one layer 30 (sometimes referred to as a photoluminescent layer or color converting layer) is a blue light (e.g., to create white backlight illumination comprising red, green and blue components, etc.) It may include quantum dots that convert to red and green light. Configurations in which the light emitting diodes 38 emit white light (eg, allowing layer 30 to be omitted, if desired) may also be used.

In configurations in which layer 30 emits white light, such as white light generated by the phosphorescent material in layer 30, the white light emitted from layer 30 in the downward (-Z) direction is a dichroic filter layer. As backlight illumination by 32, it may be reflected back through the pixel array 24 (i.e., layer 32 may help reflect the backlight outwardly away from the array 36). In configurations where the layer 30 includes, for example, red and green quantum dots, the dichroic filter 32 reflects the red and green light respectively from the red and green quantum dots to direct the backlight outwardly away from the array 36. It can be configured to help reflect. By placing the photoluminescent material of the backlight 42 (e.g., the material of the layer 30) over the diffuser layer 34, the light emitting diodes 38 are less than the light emitting diode cells of the array 36 at the centers of these cells. It can be configured to emit more light towards the edges of the (tiles), thereby helping to improve backlight illumination uniformity.

3 is a plan view of an exemplary light emitting diode array for backlight 42. As shown in FIG. 3, the light emitting diode array 36 may include rows and columns of light emitting diodes 38. Each light emitting diode 38 may be associated with a respective cell (tile region) 38C. The length (D) of the edges of the cells 38C is 2 mm, 18 mm, 1 to 10 mm, 1 to 4 mm, 10 to 30 mm, more than 5 mm, more than 10 mm, more than 15 mm, more than 20 mm, 25 It may be less than mm, less than 20 mm, less than 15 mm, less than 10 mm, or other suitable size. If desired, hexagonal tiled arrays, and arrays with light emitting diodes 38 organized in other suitable array patterns, may be used. In arrays with rectangular cells, each cell may have sides of the same length (e.g., each cell may have a square contour with four equal-length cell edges surrounding each light emitting diode. Or), each of the cells may have sides of different lengths (eg, a rectangular shape rather than a square). The configuration of FIG. 3 in which the light emitting diode array 36 has rows and columns of square light emitting diode regions such as cells 38C is exemplary only.

If desired, each cell 38C is a light source formed of an array of light emitting diode dies (e.g., a plurality of individual light emitting diodes arranged in an array such as a 2 x 2 cluster of light emitting diodes at the center of each cell 38C). 38)). For example, the light source 38' in the leftmost and bottommost cell 38C of FIG. 3 was formed of a 2 x 2 array of light emitting diodes 38 (e.g., four separate light emitting diode dies). . The diodes 38 in the light source 38 ′ may be mounted on a common package substrate, or may be mounted on a printed circuit board substrate extending over the array 36, or using other suitable arrangements, the array ( 36). In general, each cell 38C has a single light emitting diode 38, a pair of light emitting diodes 38, 2 to 10 light emitting diodes 38, at least two light emitting diodes 38, at least 4 It may comprise a light source 38' having four light-emitting diodes 38, at least eight light-emitting diodes 38, less than five light-emitting diodes 38, or any other suitable number of light-emitting diodes. Example configurations in which each cell 38C has a single light emitting diode 38 may sometimes be described herein as an example. However, this is only exemplary. Each cell 38C may have a light source 38 having any suitable number of one or more light emitting diodes 38.

4 is a cross-sectional side view of an exemplary light emitting diode. Light-emitting diodes, such as the light-emitting diode 38 of FIG. 4, may have terminals such as contacts 58. The contacts 58 are electrically connected to a printed circuit or other substrate with a conductive material such as solder (e.g., so that the light emitting diodes 38 can be soldered or otherwise mounted in an array such as the array 36 of FIG. 3). Can be combined. The light emitting diode 38 may have an n-type region 54 and a p-type region 56. Regions 54 and 56 may be formed on the substrate 52 from a crystalline semiconductor material such as gallium nitride. Substrate 52 may be formed of a transparent crystalline material such as sapphire or other suitable substrate material. A reflector layer 50 (eg, a dispersive Bragg reflector) may be formed on the substrate 52 to help direct the light emitted from the diode 38 laterally.

5 is a cross-sectional side view of an exemplary light emitting diode cell. As shown in FIG. 5, each light emitting diode cell (tile) 38C in the light emitting diode array 36 may have a reflector such as a cavity reflector 68. Reflector 68 may have a square contour (i.e., a square footprint when viewed from above), or may have other suitable shapes, and may have sheet metal (e.g., stamped sheet metal), metallized polymer film, plastic carrier. A stack of dielectric thin films forming a dielectric mirror (thin film interference mirror) on a thin metal, polymer film or molded plastic carrier, a white ink layer or other white on a polymer carrier covered with a white reflective film (e.g., a glossy polymer coating) Layered glossy white polymer sheets, diffusely reflective white reflectors, or specularly reflective white reflectors), or other suitable reflector structures. If desired, reflector 68 may be formed of a layer of cholesteric liquid crystals whose Bragg reflectivity is controlled by material birefringence (refractive index difference) and pitch, and singular or chirp for bandwidth control. May be, or may be an interference filter using a stack of layers where the refractive index difference between adjacent layers is sufficiently large (eg, n>0.1), such as a stack of multiple polymer layers or layers of different materials. The stack of polymer layers may be, for example, a stack of alternating films of polyethylene terephthalate (PET) and polymethyl methacrylate (PMMA) or an alternating of polyethylene naphthalate (PEN) and PMMA. It can be a stack of films. The light emitting diode 38 may be soldered or otherwise mounted to metal traces in the printed circuit 60. The opening in the center of the reflector 68 can accommodate the light emitting diode 38. The cells in reflector 68 may have cross-sectional profiles with curved portions to help reflect light from diode 38 upwardly as backlight illumination 44. In one exemplary configuration, a polymer film (e.g., a film coated with a dielectric thin-film interference mirror surface or a glossy white reflective surface) may be embossed using a roller (e.g., the film is a patterned structure on a heated roller). Can be thermoformed using). Following the thermoforming operations to form the curved walls of the reflector 68 in each cell 38C, a die cutting tool or other cutting devices may cut the openings for each of the light emitting diodes 38.

As shown in FIG. 5, a transparent structure such as a transparent dome structure 70 may be formed over the light emitting diode 38 to help disperse light from the light emitting diode 38 in the lateral direction. The dome structure 70 may (for example) be formed from beads of clear silicone or other transparent polymer. During operation, the light emitting diode 38 emits light that is refracted away from the Z axis by the dome structure 70. Light rays emitted from light-emitting diode 38, such as light-emitting diode 38, may be characterized by an angle A with respect to the surface normal n of light-emitting diode 38. The light 80 moving parallel to the Z dimension is parallel to the surface normal n (angle A=0°). The light 80 moving parallel to the X-Y plane is moving perpendicular to the Z dimension and the surface normal (n) (i.e., A=90°). Light 80 traveling in different angular orientations with respect to the surface normal n is characterized by the median value of the angle A.

Some rays of light 80 are oriented at relatively large angles A and are reflected upwards from reflector 68 in direction Z (e.g., reflected from reflector 68 as reflected rays 84). Light rays (82)). Other rays of light 80 are oriented at smaller angles A. For example, ray 90 is oriented at a value of a smaller angle A with respect to the surface normal n. An angle dependent filter or other layer that is at least partially reflected, e.g. layer 96 is one of vertical rays (A=0°) or nearly vertical rays at the center of cell 38C, such as ray 86 To help reflect at least some downwards while allowing more angled rays (rays striking the filter 96 at locations closer to the edges of the cavity 38C) to pass into the diffuser 34. , May be interposed between the light diffuser 34 and the light emitting diodes 38 (and the reflector 68). For example, rays such as ray 90 are reflected by layer 96 as illustrated by ray 92 before being reflected back in the upward (+Z) direction as illustrated by ray 94 It can be reflected outward and downward (in the -Z direction).

Layer 96 may be formed of multiple dielectric layers 96' (e.g., layer 96 may be formed of alternating high and low layers of silicon oxide, silicon nitride and/or other inorganic materials, organic materials. It may be a thin film interference filter formed of a dielectric stack having refractive index materials, and/or may be a layer formed of other dielectric materials and/or layers forming a thin film interference filter). In one exemplary configuration, (as an example) layer 96 has 5 layers 96', 3-6 layers 96', more than 3 layers 96', or less than 10 layers. There is (96'). Layer 96 is formed of one or more layers of reflective material (e.g., a single layer of bulk material or two or more layers of material, etc.) without forming a thin-film interference filter, or layer 96 is formed of one or more bulk coating layers and Configurations including both thin film interference filters formed from a stack of dielectric layers may also be used. If desired, the partially reflective layer 96 may be formed of a layer of cholesteric liquid crystals whose Bragg reflectivity is controlled by material birefringence (refractive index difference) and pitch, and may be singular or chirped for bandwidth control, or multiple It may be a bandpass interference filter using a stack of layers where the refractive index difference between adjacent layers, such as a stack of polymer layers or layers of other materials, is sufficiently large (eg, n>0.1). The stack of polymeric layers may be, for example, a stack of alternating films of polyethylene terephthalate (PET) and polymethyl methacrylate (PMMA) or a stack of alternating films of polyethylene naphthalate (PEN) and PMMA.

To help ensure the uniformity of the backlight 44, the light diffuser 34 and/or other structures within the backlight 42 may be provided with optional light homogenizing structures. For example, a pattern of light blocking and reflective structures such as structures 88 may be formed on the lower surface of layer 96. The structures 88 include dots, rings, square pads, pseudo-random patterns of pads that reflect and block light, or more light emitted at the center of the cell 38C than at the edges of the cell 38C. Other structures that are patterned to block The structures 88 reflect patterned ink, patterns of reflective protrusions, patterned angle-dependent thin film interference filter layer, and/or light emitted on-axis from the center of cells 38C and It may be formed with other light reflecting and light scattering structures that help absorb and/or allow light to pass upwardly towards the films 26 at the edges of the cells 38C. This helps to reduce the hot spots in the middle of the cells 38C and smooths out the light intensity changes-otherwise the light from the array 36 may be caused as it is diffused by the light diffuser 34. The structures 88 may be formed on the lower (inner) surface of the layer 96 or a separate substrate (e.g., a substrate and/or a substrate support layer 96 that is also used to carry the layer 96). May be formed on a different substrate), or may be formed at other suitable locations within the backlight unit 42.

During operation, at least some of the light from the light emitting diode 38 (e.g., light 86 in FIG. 5) emitted directly upwardly from the center of the cell 38C is by means of the optional structure 88 and/or the layer ( 96) will be reflected downwards. The reflected light will spread laterally (eg, by being reflected from cavity reflector 68). Other light, such as light 82 emitted laterally from the light-emitting diode 38, can be reflected in the cavity reflector 68 without being reflected in the structure 88 or layer 96, and the diffuser 34 upward. It will pass through and serve as a backlight 44. Light 90 will be reflected from layer 96 and reflector 68 before passing upward as light 94.

Near the edges of each cell 38C, allowing light near the edges of each cell 38C to pass directly through the diffuser 34, while recycling the light near the center of each cell 38C. The intensity of light of may be increased compared to the intensity of light near the center of each cell 38C. This helps to ensure that the backlight 44 is uniform across the surfaces of the light diffuser 34 and backlight 42. If desired, the light-scattering particles 72 (e.g., microbeads, hollow microspheres, air bubbles, and/or other light-scattering particles) are used in a diffuser layer 34 to help diffuse the emitted light. ) Can be embedded within a polymer or other material to form. The light-scattering particles 72 may have a refractive index different from that of a polymer constituting the diffuser 34. For example, the refractive index of the particles 72 may be greater than the refractive index of the polymer or other material used to form the layer 34, or may be less than the refractive index of the diffuser 34. Light-scattering features (e.g., bumps, ridges, and/or other protrusions, grooves, pits, or other depressions) may cause light-scattering particles 72 in diffuser 34. In addition to or instead of including ), it may be formed on the upper and/or lower surface of the light diffuser 34. In some configurations, the light is formed by a photoluminescent layer (e.g., a photoluminescent layer 30 that may be formed of phosphors and/or quantum dots) in the backlight unit 42 in addition to or instead of the diffuser 34. Can be used to spread.

In the exemplary configuration of FIG. 5, a unitary structure 88 (eg, a single pad) has been provided over the light emitting diodes 38 in each cell 38C. If desired, a cluster of pads (circular pads, square pads, or other shapes of pads) may be formed over each light emitting diode. The density of the pads in each cluster (eg, the number of pads per unit area and/or the area consumed by the pads per unit area) may vary as a function of position. For example, each pad cluster may have more pads and/or larger pads near the center of the pad cluster than near the edges of the pad cluster. The use of graded structures, such as pad clusters with graded pad densities (eg, pads concentrated over diodes 38) can help smoothly reduce hot spots in cells 38C. If desired, structures 88 (e.g., in configurations in which the layer 96, lens 70, and/or other structures within backlight unit 42 are configured to homogenize the emitted light without structures 88). Can be omitted.

In the exemplary configuration of FIG. 5, a partially reflective layer such as layer 96 (e.g., a thin metal layer, a stack of dielectric thin film layers, one or more other partially reflective layers, etc.) is provided with a light diffuser 34 and light emitting diodes 38. ) Is provided between. Layer 96 may be formed as a coating on the lower surface of diffuser 34 and/or may be embedded within diffuser 34 and/or may be separate from diffuser 34. Light reflected downward from the layer 96 may be reflected back in the upward direction by the cavity reflector 68. Thereby, the presence of layer 96 helps to improve the number or reflections for each ray, and thus improves the homogenization of the emitted light from the LED array 36 before such light passes through layer 34. Let it. If desired, additional diffusion may be provided by a diffusing coating on the diffuser 34 and/or other layers in the backlight unit 42 (e.g., the diffusing coating is a diffuser 34 in which the light-scattering particles 72 are embedded. ) Can be formed with a polymer layer on the upper surface of). If desired, the density of the light-scattering particles 72 can be graded.

In configurations where the partially reflective layer 96 is formed using a thin film interference filter arrangement, layer 96 includes dielectric layers 96'. Layers 96' of layer 96 are, for example, inorganic layers of different refractive indices (e.g., aluminum oxide, silicon oxide, silicon nitride, titanium oxide, other metal oxides, nitrides, and/or oxynitrides). Alternating high and low refractive index layers formed of materials such as). Layers 96' may be configured to form a thin film interference filter in which the transmission spectrum of layer 96 changes as a function of the angle of incidence. This causes the transmission (T) of light at a given wavelength (λ), such as the wavelength (λb) in FIG. 6, which may be associated with the blue light emitted from the diode 38, depending on the angle of incidence of that light relative to the layer 96. Let it change.

As shown in Figure 6, the layer 96 has the transmission spectrum when exposed to light from the diode 38 at an angle A1 (e.g., close to 0° and parallel to the surface normal n in Figure 5). It can represent (110), and can represent the transmission spectrum 112 for light moving at angles around the angle A2 (eg, 45°). Due to the change in the transmission spectrum of layer 96 as a function of the angle of incidence, the blue light at λb will be at least partially reflected when characterized by the angle of incidence of A1 (e.g., the transmission (T) is more than a given amount. Will be less), and will be less reflective when characterized by an angle of incidence of A2 or an angle of incidence greater than A2 greater than A1 (e.g., transmission (T) will be more than a given amount). As the curves of FIG. 6 demonstrate, at least some of the blue light emitted from the light emitting diodes 38 at the center of the cells 38C (e.g., light at wavelength λb) is reflected, and therefore (surface normal ( It will be recycled when emitted directly upward (parallel to n), whereas blue light emitted at more inclined angles A will be allowed to pass through when impinging upon layer 96. This may help reduce hot spots for emitted light at the centers of cells 38C.

Reflector 68 in each cell 38C to help capture the light that has spread laterally outward from the light emitting diode 38 at the center of each cell 38C towards the periphery of each cell 38C. ), the hot spots can be further reduced.

An exemplary configuration for a portion of reflector 68 covering exemplary cell 38C is shown in the perspective view of FIG. 7. As shown in the example of FIG. 7, the reflector 68 of the cell 38C is at the same height along the peripheral edges 38E of the cell 38C with respect to the printed circuit 60 of each of the walls of the reflector 68. (See, for example, height (H) in Figure 5) can be configured to rise. As a result, the height of the reflector 68 along each edge 38E between the opposite cell corners 38D (the distance between the edge 38E and the points on the printed circuit 60) is constant, and the reflector Each edge of 68 follows a straight line along each straight cell edge 38E. With this configuration, the profile of the cell 38C (e.g., edge-to-edge profile 152) taken along the X or Y dimensions is at an intermediate point along the cell edge 38E (e.g., of edge 38E). It will rise to vertex 38E') at a point that is halfway between the opposite corner endpoints. The cross-sectional profile of the cell 38C taken along a diagonal direction (between each corners 38D), such as the corner-to-corner profile 154, will rise to the vertex at the cell corner 38D. Each cell-edge-to-cell-edge profile vertex (e.g., edge midpoints 38E') is, on the printed circuit 60, a respective cell-corner-to-cell-corner profile vertex (edges It is located at the same distance (height H in Fig. 5) as the corner points 38D corresponding to the end points of 38E.

In the example of FIG. 8, the reflector 68 of the cell 38C is configured such that the reflector 68 does not rise to the same height H at each point along the edges 38E. Rather, the edges 38E have curved shapes that go down towards their midpoints. In particular, each edge 38E is characterized by a maximum height H at the corners 38D (end points of the curved edge 38E) and at a minimum height that is less than H in the middle of the edge 38E. Characterized by Therefore, the height of the reflector 68 along each edge 38E between the opposing cell corners 38D is not constant, and each edge of the reflector 68 is drooping along the cell edge 38E. ) Follow a curved line. The cross-sectional profile (e.g., cell-edge-to-cell-edge profile 152) of the reflector 68 of the cell 38C of FIG. 8 taken along the X or Y dimensions is at an intermediate point along the cell edge 38E. The cross-sectional profile of the cell 38C taken along the diagonal direction between the corners 38D, such as the corner-to-corner profile 154, will rise to a vertex 38E' of height less than H, which is It will rise to the apex of height H, at cell corner 38D (as in reflector 68 of cell 38C in Fig. 7). Therefore, each cell-edge-to-cell-edge profile vertex (point 38E') is located closer to the printed circuit 60 than each cell-corner-to-cell profile vertex (point 38D). Is located in

9 is a plan view of a portion of the array 36. Edge-to-edge cross-sectional profiles for reflector 68 such as profiles 152 in FIGS. 7 and 8 are taken along line 204 and viewed in direction 206. Corner-to-corner cross-sectional profiles for reflector 68 such as profiles 154 in FIGS. 7 and 8 are taken along line 200 and viewed in direction 202. Edge points 38E' are located at a distance ED from the light emitting diode 38 in directions X and Y, where ED is equal to one half of the cell dimension (cell edge length) D. Corner points 38D are located at a distance DD from the light emitting diode 38 along a dimension 208 defined by an axis oriented at a 45° angle to both the X and Y axes of FIG. 9.

10 and 11 are side cross-sectional views of exemplary reflector configurations for cells 38C in array 36.

The arrangement shown in Fig. 10 corresponds to a configuration of the type shown in Fig. 7 in which the edges 38E are straight. The reflector portion 68-1 corresponds to a portion of the reflector 68 that runs between the light emitting diode 38 and the corner 38D of the cell 38C, and the reflector 68 of the cell 38C in FIG. It has a curved profile that matches the profile 154. The reflector portion 68-2 corresponds to a portion of the reflector 68 that runs between the light emitting diode 38 and the edge midpoint 38E' of the cell 38C, and the profile of the cell 38C in FIG. 152) and has a curved profile matching. As shown in Fig. 10, both points 38E', 38D in this type of arrangement are located at a distance H from the plane on which the printed circuit 60 lies.

The arrangement shown in FIG. 11 corresponds to a configuration of the type shown in FIG. 8 in which the edges 38E are curved and go down toward the printed circuit 60 at positions between the corners 38D. The reflector portion 68-1 of FIG. 11 corresponds to a portion of the reflector 68 that runs between the light emitting diode 38 and the corner 38D of the cell 38C, and the reflector of the cell 38C of FIG. 68) has a curved profile matching profile 154. The reflector portion 68-2 corresponds to a portion of the reflector 68 that runs between the light emitting diode 38 and the edge midpoint 38E' of the cell 38C, and the profile of the cell 38C in FIG. 152) and has a curved profile matching. The corner points 38D of the cell 38C in this arrangement type are located at a distance H from the plane on which the printed circuit 60 lies, while the edge midpoints, such as points 38E', are the printed circuit ( 60) is located at a distance (H') less than H from the plane on which it lies.

If desired, reflector 68 may have a Fresnel shape in which reflector 68 has a series of concentric rings 68-3, each of which is a corresponding profile of a profile 152 or 154. It has a profile that matches the part. The use of a Fresnel reflector structure (reflective Fresnel lens structure) for the reflector 68 allows the distance between the printed circuit 60 and the layer 96 to be minimized, which allows the reflector 68 in this type of arrangement. This is because the maximum spacing between the and printed circuit 60 may be less than the maximum spacing between the reflector 68 and the printed circuit 60 in the types of configurations shown in FIGS. 7 and 8.

12 and 13 show how the cross-sectional profiles of reflector 68 can have elliptical or parabolic portions to improve the homogeneity of the emitted light 44.

The use of elliptical shapes for portions of the cross-sectional profiles of reflector 68 in cells 38C is shown in FIG. 12. As shown in Fig. 12, light-emitting diode 38 is associated with a virtual image at position F1 (the reflective position of light-emitting diode 38 at layer 96). This position can form one of the two focal points for the ellipse that are used to define a portion of the profile for the reflector 68. Two exemplary ellipses are shown in the example of FIG. 12. The ellipse 220 has a first focus F1 and a second focus F2. The ellipse 222 has a first focal point F1 and a second focal point F2'. Focal points F2 and F2' may lie in the plane of layer 96. Portion 220 ′ of ellipse 220 may form an edge-to-edge profile for reflector 68, such as profile 152 in FIGS. 7 and 8. Portion 222 ′ of ellipse 222 may form an edge-to-edge profile for reflector 68, such as profile 154 in FIGS. 7 and 8.

The use of parabolic shapes for portions of the cross-sectional profiles of reflector 68 in cells 38C is shown in FIG. 13. As shown in FIG. 13, the reflector 68 may have cross-sectional profiles including parabolic portions (eg, edge-to-edge cross-sectional profile and/or corner-to-corner cross-sectional profile). Point PF1 may be associated with a focal point of a parabolic defining the shape of a portion of the profile for reflector 68. The axis of symmetry for the parabola may be oriented at a non-zero angle with respect to the X-axis (as illustrated by axis 242), or may have other suitable orientations (see, eg, horizontal axis 240). If desired, the axis of symmetry relative to the parabola and the focal point of the parabola can have other suitable positions (see, for example, focal point PF2).

The ray trace models can help disperse the light from the light-emitting diode 38 evenly over the surface of each cell 38C, so that the elliptical and parabolic profiles for the reflector 68 can help each cell 38C. It has been demonstrated that it emits a uniform backlight illumination 44. If desired, reflector 68 can have other shapes. The use of elliptical and parabolic profiles for portions of reflector 68 is exemplary.

Exemplary layers that may be incorporated into backlight 42 are shown in FIGS. 14, 15, 16, and 17.

Optical layers in backlight 42, such as optical films 26, may include thin film interference filter layers. These layers may be formed as a stack of inorganic and/or organic dielectric layers of alternating refractive indices (see, eg, the dielectric stack of layers 300 in FIG. 14). Thin film interference filters can form broadband (white light) reflectors (sometimes referred to as mirrors or partial mirrors), and/or other (e.g., to form a filter with a non-flat visible light reflection spectrum). Filters can be formed that reflect some colors of light more than those. Thin film interference filters may be configured to transmit unreflected light (eg, to have high light transmission at unreflected wavelengths). Dielectric stacks, such as the stack of layer 300 of FIG. 14, can be formed on polymer or glass substrates, and/or be combined with layers of material that perform other functions (e.g., as thin film interference filter coating layers). I can.

If desired, brightness enhancing films (sometimes referred to as prism films, light-collimating layers, or light-collimating prism layers) may be used to collimate light 44. 15 is a cross-sectional side view of an exemplary prism film. As shown in Fig. 15, the prism film 302 has a series of parallel ridges 304 extending into the page and having triangular cross-sectional shapes. The ridges 304 may face upwards (outwardly) towards the observer to help collimate light 44 towards the observer.

Microlens array layers, such as the exemplary microlens array layer 306 of FIG. 16 may be used to spread and homogenize the light 44. Layer 306 may be relatively thin so as not to unduly increase the thickness of display 14. For example, layer 306 can be 5 to 100 microns thick, at least 10 microns thick, or less than 150 microns thick. In the example of FIG. 16, the top (outward facing) surface 309 of the layer 306 has an array of convex lenses, such as convex microlenses 308, and the lower (inward facing) surface 311 of the layer 306. ) Has an array of concave lenses, such as concave microlenses 308. In general, any of the surfaces of layer 306 may be planar, and/or any of the surfaces of layer 306 may have convex lenses, and/or any of the surfaces of layer 306 may be concave. You can have lenses. The configuration of FIG. 16 is only exemplary. The microlenses 308 may have lateral dimensions of about 15 to 25 microns, at least 10 microns, less than 30 microns, or other suitable lateral dimensions, and may have heights of about 3 to 20 microns. A non-uniformity pattern can be used for the microlenses 308 to reduce moiré effects.

Optical layers 26 may include one or more light-diffuser layers. In the exemplary configuration of FIG. 17, the light-diffuser layer 310, which may sometimes be referred to as a diffuser or diffuser layer, is a substrate 312 on which light-scattering particles 314 (e.g., titanium oxide particles) have been embedded. Have the same polymer substrate. If desired, other diffuser configurations can be used.

An exemplary configuration for a display 14 in which one or more layers, eg they are integrated into the backlight 42, is shown in FIG. 18. As shown in the exemplary configuration of FIG. 18, the backlight unit 42 may include a light source such as a light emitting diode array 36. Light from the array 36 (e.g., blue light from the blue light emitting diodes in the array 36) passes through the layers stacked on top of the array 36 upward in the +Z direction, and the pixel array ( Exit the backlight unit 42 as a backlight illumination 44 for 24).

The backlight 42 of the display 14 of FIG. 18 may have a diffuser such as the diffuser layer 310. The diffuser layer 310 may be positioned over the array 36. The lower surface of the diffuser layer 310 may be coated with a thin film interference filter 320. The filter 320 may be formed of a stack of alternating refractive index dielectric layers (see, eg, dielectric stack in FIG. 14) that was configured to partially transmit and partially reflect blue light. For example, the reflectivity of filter 320 (sometimes referred to as a blue-light reflective filter or partial reflective filter) at blue wavelengths is 50% to 90%, at least 60%, less than 80%, or other suitable Value (eg, the filter may be a partially transmitting blue-reflective filter that partially transmits blue light). At red and green wavelengths, this filter can have a higher or lower reflectivity than at blue wavelengths.

A photoluminescent layer, such as a yellow phosphor layer 316, may convert at least some of the light from the light emitting diodes of the array 36 (e.g., at least some of the blue light from the blue light emitting diodes in the array 36) to red and green light. To allow the layer 316 to emit white light backlight illumination 44. Some of the red and green light can be emitted downwards. In order to prevent lateral leakage of red and green light, a thin film interference filter such as filter 318 may be formed on the lower surface of layer 316. The filter 318 may be formed of a dielectric stack that was configured to reflect red and green light while passing blue light (e.g., the dielectric stack 300 of FIG. 14) (e.g., the filter 318 is blue-transmitting. -And-red-and-green-reflective thin film interference filter).

A microlens array layer 306 (FIG. 16) may be placed over layer 316 and may be used to spread light 44 to prevent hot spots.

Light 44 may be collimated towards the observer 20 using one or more prism films 302. In the example of FIG. 18, display 14 has two prism films 302. The prisms of the films 302 may be oriented perpendicular to each other. For example, when the prisms of the lower prism film are parallel to the X axis, the prisms of the upper prism film may be parallel to the Y axis. A reflective polarizer 322 can be positioned over the prism films 302 to help recycle the light, thereby improving backlight efficiency. The reflective polarizer 322 may reflect (recycle) orthogonally polarized light while passing linearly polarized light along a given axis.

According to an embodiment, there is provided a display including a plurality of pixels and a backlight configured to generate backlight illumination for the plurality of pixels, the backlight being configured to emit light and a light source arranged in a plurality of individual cells And a reflector for reflecting light through the plurality of pixels from the light sources, the reflector having a cross-sectional profile in each cell having a portion selected from the group consisting of: a parabolic portion and an elliptical portion.

According to another embodiment, the pixels comprise an array of pixels, and the light sources comprise a two-dimensional array of light sources arranged in a two-dimensional array of individual cells.

According to another embodiment, each light source has at least one light emitting diode.

According to another embodiment, a display includes an array of light emitting diodes and a light diffuser layer interposed between the array of pixels and a partially reflective layer interposed between the light diffuser layer and the array of light emitting diodes.

According to another embodiment, the partially reflective layer comprises: a partially reflective layer selected from the group consisting of: a thin film interference filter with angle dependent light transmission properties, a cholesteric liquid crystal layer, and a stack of alternating refractive index polymer films.

According to another embodiment, the display comprises a printed circuit, the light emitting diodes are mounted on the printed circuit, and in each cell the reflector has four straight edges surrounding each of the light emitting diodes, and four edges Each point along each is separated by a common distance from the printed circuit.

According to another embodiment, the display comprises a printed circuit, the light emitting diodes are mounted on the printed circuit, in each cell the reflector has 4 corners and 4 curved edges, the 4 curved edges Each of them extends between the four corners of each pair, and each of the four curved edges has endpoints separated from the printed circuit by a first distance and separated from the printed circuit by a second distance less than the first distance. Have a midpoint.

According to another embodiment, the display comprises a light diffuser layer interposed between the array of pixels and the array of light emitting diodes, the partially reflective layer comprising a coating on the light-diffuser layer, the reflector comprising: a glossy white reflector, And a reflector selected from the group consisting of a diffuse reflective white reflector, a specular reflective white reflector, a stack of thin film dielectric layers forming a thin film interference mirror, a cholesteric liquid crystal layer, and a stack of polymer films of alternating refractive index.

According to another embodiment, the reflector comprises a reflector selected from the group consisting of: a glossy white reflector, a diffuse reflective white reflector, or a specular white reflector.

According to another embodiment, the reflector comprises a reflector selected from the group consisting of: a stack of thin film dielectric layers forming a thin film interference mirror, a cholesteric liquid crystal layer, and a stack of polymer films of alternating refractive index.

According to another embodiment, the light emitting diodes comprise blue light emitting diodes, and the display comprises a partially reflective layer interposed between the light emitting diodes and the array of pixels.

According to another embodiment, each light source comprises at least two light emitting diodes.

According to one embodiment, there is provided a display comprising a backlight configured to generate backlight illumination for an array of pixels and an array of pixels, the backlight being a two-dimensional array of light emitting diode cells-each of the light emitting diode cells emits light At least one light-emitting diode configured to-and a reflector for reflecting light through the array of pixels from the light-emitting diodes, the reflector having a cross-sectional profile in each cell having a portion that is parabolic.

According to another embodiment, the display has a light diffuser layer interposed between the array of pixels and the array of light-emitting diodes-the light-emitting diodes are configured to emit blue light-and a light-diffuser forming a thin film interference filter with angle dependent transmission. Includes a layered coating.

According to another embodiment, the light emitting diodes are configured to emit blue light.

According to another embodiment, the display comprises a printed circuit, the light emitting diodes are mounted on the printed circuit, and in each cell the reflector has 4 corners and has 4 straight edges extending between the corners, Each point along each of the four straight edges is separated by a common distance from the printed circuit.

According to another embodiment, the display comprises a printed circuit, the light emitting diodes are mounted on the printed circuit, in each cell the reflector has 4 corners and 4 curved edges, the 4 curved edges Each of them extends between the four corners of each pair, and each of the four curved edges has endpoints separated from the printed circuit by a first distance and separated from the printed circuit by a second distance less than the first distance. Have a midpoint.

According to another embodiment, the reflector comprises a layer selected from the group consisting of: a glossy white layer and a layer with a stack of dielectric layers forming a thin film interference mirror.

According to another embodiment, the light emitting diodes include white light emitting diodes.

According to an embodiment, there is provided a display comprising an array of pixels and a backlight configured to generate backlight illumination for the array of pixels, wherein the backlight is configured to emit light and is arranged in a two-dimensional array of individual cells. A two-dimensional array of diodes and a reflector for reflecting light through the array of pixels from the light-emitting diodes, the reflector having a cross-sectional profile in each cell having an elliptical portion.

According to another embodiment, the light-emitting diodes comprise blue light-emitting diodes, and the display comprises an optical diffuser layer interposed between the array of pixels and the array of light-emitting diodes and a light-diffuser layer forming a thin film interference filter with angle dependent transmission. And the reflector comprises: a layer selected from the group consisting of a glossy white layer and a layer with a stack of dielectric layers forming a thin film interference mirror.

According to an embodiment, there is provided a display comprising pixels configured to display images and a backlight configured to generate backlight illumination for the pixels, the backlight comprising a two-dimensional array of light emitting diode cells-each of the light emitting diode cells Comprising at least one light-emitting diode configured to emit light-a reflector having a curved cross-sectional profile that reflects light through the array of pixels from the light-emitting diodes and a micro between the two-dimensional array of pixels and the light-emitting diode cells. And a lens array layer.

According to another embodiment, the backlight comprises a phosphor layer between a microlens array layer and a two-dimensional array of light emitting diode cells, a diffuser layer between the phosphor layer and a two-dimensional array of light emitting diode cells, and a first thin film on the diffuser layer. An interference filter and a second thin film interference filter on the phosphor layer.

According to another embodiment, the backlight includes a diffuser layer between the phosphor layer and the two-dimensional array of light emitting diode cells.

According to yet another embodiment, the backlight includes a first thin film interference filter on the diffuser layer and a second thin film interference filter on the phosphor layer.

According to an embodiment, the light emitting diodes include blue light emitting diodes configured to emit blue light, the first thin film interference filter is configured to partially transmit blue light, and the second thin film interference filter transmits blue light and blue light It is configured to reflect red and green light generated from the phosphor layer in response to the light, and the backlight is reflected between the first and second prism films between the pixels and the microlens array layer and the second prism film and the reflection between the pixels. Includes a polarizer.

According to another embodiment, the first thin film interference filter is configured to partially transmit blue light.

According to another embodiment, the second thin film interference filter is configured to transmit blue light and to reflect red and green light generated in the phosphor layer in response to the blue light.

According to another embodiment, the backlight includes first and second prism films between the pixels and the microlens array layer.

According to another embodiment, the backlight includes a reflective polarizer between the pixels and the second prism film.

The foregoing is only exemplary, and various modifications may be made to the described embodiments. The above-described embodiments may be implemented individually or in any combination.

Claims (30)

As a display,
A plurality of pixels; And
A backlight configured to generate backlight illumination for the plurality of pixels, the backlight comprising:
Light sources configured to emit light and arranged in a plurality of respective cells; And
A reflector that reflects the light from the light sources through the plurality of pixels, the reflector having a plurality of cross-sectional profiles in each cell, each cross-sectional profile being a portion selected from the group consisting of a parabolic portion and an elliptical portion Has-including,
The display,
A light diffuser layer interposed between the light sources and the plurality of pixels;
An angle dependent filter interposed between the light diffuser layer and the light sources; And
Layer of photoluminescent material
In addition,
Wherein the light diffuser layer is interposed between the layer of photoluminescent material and the plurality of pixels, and the light source is configured to emit more light toward the edges of the cells than toward the center of the cells. . The display of claim 1, wherein the light sources comprise a two-dimensional array of the light sources arranged in a two-dimensional array of the respective cells. The display of claim 2, wherein each light source has at least one light emitting diode. delete The display according to claim 3, wherein the angle dependent filter is a thin film interference filter having angle dependent light transmission characteristics. The method of claim 5, further comprising a printed circuit, wherein the light emitting diodes are mounted on the printed circuit, and the reflector in each cell has four straight edges surrounding each of the light emitting diodes, and the Each point along each of the four edges is separated by a common distance from the printed circuit. The method of claim 5, further comprising a printed circuit, wherein the light emitting diodes are mounted on the printed circuit, and in each cell, the reflector has 4 corners and 4 curved edges, and the 4 curved edges Each of the shaped edges extends between the four corners of each pair, and each of the four curved edges has end points separated from the printed circuit by a first distance and a second distance less than the first distance. A display, having an intermediate point separated from the printed circuit by as much as possible. 6. The display of claim 5, wherein the angle dependent filter comprises a coating on the light diffuser layer. 9. The display of claim 8, wherein the reflector comprises a reflector selected from the group consisting of: a glossy white reflector, a diffuse reflective white reflector, or a specularly reflective white reflector. 9. The display of claim 8, wherein the reflector comprises a reflector selected from the group consisting of: a stack of thin film dielectric layers forming a thin film interference mirror, a cholesteric liquid crystal layer, and a stack of polymer films of alternating refractive index. 4. The display of claim 3, wherein the light emitting diodes comprise blue light emitting diodes. The display of claim 2, wherein each light source comprises at least two light emitting diodes. As a display,
An array of pixels; And
A backlight configured to generate backlight illumination for the array of pixels, the backlight comprising:
A two-dimensional array of light emitting diode cells, each of the light emitting diode cells comprising at least one light emitting diode configured to emit light; And
A reflector that reflects light from the light emitting diodes through the array of pixels, the reflector having at least three cross-sectional profiles each having a parabolic portion in each cell, the at least three fragment profiles being edge-to- Including edge cross-sectional profiles and corner-to-corner cross-sectional profiles,
The display,
A light diffuser layer interposed between the array of pixels and the array of light emitting diodes; And
The display further comprising a coating on the light diffuser layer forming a thin film interference filter with angle dependent transmission. delete 14. The display of claim 13, wherein the light emitting diodes are configured to emit blue light. The method of claim 15, further comprising a printed circuit, wherein the light emitting diodes are mounted on the printed circuit, and in each cell, the reflector has four corners, and four straight edges extending between the corners. A display, wherein each point along each of the four straight edges is separated by a common distance from the printed circuit. The method of claim 15, further comprising a printed circuit, wherein the light emitting diodes are mounted on the printed circuit, and in each cell, the reflector has 4 corners and 4 curved edges, and the 4 curved edges Each of the shaped edges extends between the four corners of each pair, and each of the four curved edges has end points separated from the printed circuit by a first distance and a second distance less than the first distance. A display, having an intermediate point separated from the printed circuit by as much as possible. 16. The display of claim 15, wherein the reflector comprises a layer selected from the group consisting of: a glossy white layer and a layer having a stack of dielectric layers forming a thin film interference mirror. 14. The display of claim 13, wherein the light emitting diodes comprise white light emitting diodes. As a display,
An array of pixels; And
A backlight configured to generate backlight illumination for the array of pixels, the backlight comprising:
A two-dimensional array of light emitting diodes configured to emit light and arranged in a two-dimensional array of individual cells; And
A reflector for reflecting light from the light-emitting diodes through the array of pixels-the reflector has a cross-sectional profile in each cell having a portion having an elliptical shape, the cross-sectional profiles being edge-to-edge cross-sectional profiles and Corner-to-corner cross-sectional profiles, the elliptical shape comprising a first elliptical shape corresponding to the edge-to-edge cross-sectional profiles and a second elliptical shape corresponding to the corner-to-corner cross-sectional profiles, The first oval shape includes-different from the second oval shape,
The display,
A light diffuser layer interposed between the array of pixels and the array of light emitting diodes; And
A coating on the light diffuser layer forming a thin film interference filter with angular dependent transmission, the reflector comprising: a layer selected from the group consisting of a glossy white layer and a layer with a stack of dielectric layers forming a thin film interference mirror. Further comprising, a display. delete As a display,
Pixels configured to display images; And
A backlight configured to generate backlight illumination for the pixels, the backlight comprising:
A two-dimensional array of light emitting diode cells, each of the light emitting diode cells comprising at least one light emitting diode configured to emit light;
A reflector having a curved cross-sectional profile having a selected one of a parabolic shape and an elliptical shape, the reflector reflecting light from the light emitting diodes through the array of pixels;
A microlens array layer between the pixels and the two-dimensional array of light emitting diode cells; And
Phosphor layer between the microlens array layer and the two-dimensional array of light emitting diode cells-the at least one light emitting diode emits more light toward the edges of the light emitting diode cells than toward the center of the light emitting diode cells Configured to-
Containing, a display. delete 23. The display of claim 22, wherein the backlight further comprises a diffuser layer between the phosphor layer and the two-dimensional array of light emitting diode cells. 25. The method of claim 24, wherein the backlight further comprises a first thin film interference filter on the diffuser layer and a second thin film interference filter on the phosphor layer, the light emitting diodes comprising blue light emitting diodes configured to emit blue light , The first thin film interference filter is configured to partially transmit the blue light, and the second thin film interference filter transmits the blue light and reflects red and green light generated from the phosphor layer in response to the blue light And the backlight further includes first and second prism films between the pixels and the microlens array layer, and the backlight adds a reflective polarizer between the second prism film and the pixels Included as, display. delete delete delete delete delete

Images