JP7000429B2 - Display with direct backlight unit - Google Patents

Description

This application is the international patent application PCT / US18 / 15776 filed on January 29, 2018, the US patent application Nos. 15/819,085 filed on November 21, 2017, and March 2017. It claims the priority of US Provisional Patent Application No. 62 / 466,492 filed on the 3rd, which is incorporated herein by reference in its entirety.
The present invention relates generally to displays, and more specifically to backlit displays.

Electronic devices often include displays. For example, computers and cellular phones may include a backlit liquid crystal display. The side backlight unit has a light emitting diode that radiates light into the edge surface of the light guide plate. The light guide plate then disperses the emitted light laterally across the display to serve as backlight illumination. The direct backlight unit has an array of light emitting diodes that emit light vertically through the display.

Direct backlights may have light emitting diodes with local brightness adjustments that allow for extended dynamic range. However, if care is not taken, the direct backlight can be thick and can also produce non-uniform backlight illumination.

The display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated by backlight illumination from the backlight unit. The backlight unit may include an array of light emitting diodes and a light reflector that helps reflect light from the light emitting diodes through the pixel array. Each light emitting diode may be placed in its own cell. In each cell, the light reflector may have a cross-sectional shape that includes a parabolic or elliptical portion.

A diffuser in the display may be used to homogenize the light from the array of light emitting diodes. A phosphorescent layer and other optical films may be superimposed on the diffuser.

The light emitting diode may be a blue light emitting diode. A partially reflective layer may be interposed between the diffuser and the array of light emitting diodes. The partially reflective layer may be formed from a laminate of dielectric layers on the diffuser. The laminate of the dielectric layers may form a thin film interference filter having an angle-dependent transmittance.

The light emitting diode may be attached to the printed circuit or may protrude through the opening of the light reflector. The light reflector may be formed from a reflective material such as a reflective white layer, or from a dielectric laminate forming a thin film interference mirror.

FIG. 6 is a diagram of an exemplary electronic device having a display according to an embodiment.

FIG. 6 is a side sectional view of an exemplary display according to an embodiment.

It is a top view of the exemplary light emitting diode array for a direct backlight unit according to one embodiment.

It is a side sectional view of an exemplary light emitting diode according to one embodiment.

FIG. 6 is a side sectional view of an exemplary light emitting diode in a cavity reflector showing how light can be emitted from a light emitting diode from the light emitting diode at various angles, depending on one embodiment.

FIG. 5 is a graph showing how a layer having a light transmittance that changes with an angle can be overlapped with the light emitting diode and the reflective layer of FIG. 5 according to one embodiment.

It is a perspective view of the cell of the cavity reflector for a backlight unit according to one Embodiment. It is a perspective view of the cell of the cavity reflector for a backlight unit according to one Embodiment.

It is a top view of a part of the backlight unit by one Embodiment.

FIG. 7 is a side sectional view of an exemplary cavity reflector of the type shown in FIG. 7 according to an embodiment.

FIG. 6 is a side sectional view of an exemplary cavity reflector of the type shown in FIG. 8 according to an embodiment.

FIG. 6 is a cross-sectional view of an exemplary cavity reflector comprising a portion having an elliptical contour according to one embodiment.

FIG. 6 is a cross-sectional view of an exemplary cavity reflector comprising a portion having a parabolic contour according to one embodiment.

FIG. 6 is a side sectional view of an exemplary laminate of dielectric layers such as a dielectric layer in which the refractive index changes alternately, which forms a thin film interference filter according to an embodiment.

FIG. 3 is a side sectional view of an exemplary optical interference layer such as a prism film according to an embodiment.

It is a side sectional view of an exemplary microlens array layer according to one embodiment.

It is a side sectional view of an exemplary diffuser layer according to one embodiment.

FIG. 6 is a side sectional view of an exemplary display according to an embodiment.

The electronic device may be equipped with a backlit display. The backlit display may include a liquid crystal pixel array or other display structure that is backlit by light from a direct backlight unit. FIG. 1 shows a perspective view of an exemplary electronic device of the type that may include a display with a direct backlight unit. The electronic device 10 of FIG. 1 is a computing device such as a laptop computer, a monitor for a computer including an embedded computer, a tablet computer, a cellular telephone, a media player, or another handheld or portable electronic device, a watch-type device, or a pendant type. Does not include devices, headphone or earphone devices, devices embedded in glasses or other devices worn on the user's head, or other smaller devices such as wearable or miniature devices, televisions, embedded computers. In embedded systems such as computer displays, gaming devices, navigation devices, systems that mount electronic devices with displays in kiosks or automobiles, devices that implement two or more of these devices, or other electronic devices. There may be.

As shown in FIG. 1, the device 10 may include a display such as a display 14. The display 14 may be mounted inside the housing 12. The housing 12 may also be referred to as an enclosure or case and may be plastic, glass, ceramic, fiber composites, metals (eg, stainless steel, aluminum, etc.), other suitable materials, or of these materials. It can be formed by any combination of two or more. The housing 12 may be formed by using a single structure machined or molded as a part or all of the housing 12, or a plurality of structures (for example, an internal frame structure, an external housing). It may be formed using one or more structures forming a surface, etc.).

The housing 12 may have a stand, such as an optional stand 18, a housing portion that moves relative to each other to form a laptop computer or other device with moving parts. ), In the form of a cellular telephone or tablet computer (eg, in an arrangement where the stand 18 is omitted), and / or may have other suitable configurations. The configuration of the housing 12 shown in FIG. 1 is exemplary.

The display 14 is a conductive capacitive touch sensor electrode or other touch sensor component (eg, a resistance touch sensor component, an acoustic touch sensor component, a force-based touch sensor component, an optical-based touch. It may be a touch screen display incorporating a layer (such as a sensor component), or it may be a non-touch sensitive display. Capacitive touch screen electrodes may be formed from a pad of indium tin oxide or an array of other transparent conductive structures.

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

As shown in FIG. 2, the display 14 may include a pixel array such as a pixel array 24. The pixel array 24 may include an array of pixels such as the pixel 16 in FIG. 1 (eg, an array of pixels having rows and columns of pixels 16). The pixel array 24 may be formed from a liquid crystal display module (sometimes referred to as a liquid crystal display or liquid crystal layer) or other suitable pixel array structure. The liquid crystal display forming the pixel array 24 is, for example, interposed between the upper and lower splitters, the thin film transistor layer interposed between the upper and lower splitters, and the thin film transistor layer between the color filter layer and the 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.

An image may be displayed on the pixel array 24 during the operation of 14. A backlight unit 42 (sometimes referred to as a backlight, a backlight layer, a backlight structure, a backlight module, a backlight system, etc.) is used to generate a backlight illumination 44 that passes through a pixel array 24. May be good. This illumination illuminates any image on the pixel array 24 for observation by an observer such as the observer 20 looking at the display 14 in direction 22.

The backlight unit 42 may include an optical film 26, a light diffuser 34 such as a light diffuser (light diffuser layer), and a light emitting diode array 36. The light emitting diode array 36 may include a two-dimensional array of light sources such as the light emitting diode 38 that produces the backlight illumination 44. As an example, the light emitting diodes 38 may be arranged in rows and columns, or may be in the XY plane of FIG.

The light emitting diodes 38 may be controlled all at once by a control circuit within the device 10 or (eg, to implement a local dimming mechanism that helps improve the dynamic range of the image displayed on the pixel array 24). It may be controlled individually. The light generated by each light emitting diode 38 travels upward along dimension Z through the light diffuser 34 and the optical film 26 and then through the pixel array 24. The light diffuser 34 may include a light scattering structure that helps diffuse the light from the light emitting diode array 36, thereby providing a uniform backlight illumination 44. The optical film 26 may include a film such as the dichroic filter 32 phosphor layer 30 and the film 28. The film 28 may include a luminance-enhancing film that serves to collimate the light 44, thereby improving the luminance of the display 14 relative to the user 20 and / or other optical film (eg, a compensating film).

The light emitting diode 38 can emit light of any suitable color. In one exemplary configuration, the light emitting diode 38 emits blue light. The dichroic filter layer 32 may be configured to allow blue light from the light emitting diode 38 to pass through and reflect light in other colors. The blue light from the light emitting diode 38 is converted to white light by an optical luminescence material such as a phosphor layer 30 (eg, a layer of a white phosphor material or other optical luminescence material that converts blue light to white light). May be done. If desired, other optical luminescence materials may be used to convert the blue light to light of a different color (eg, red light, green light, white light, etc.). For example, one layer 30 (sometimes referred to as an optical luminescence layer or color conversion layer) may contain quantum dots that convert blue light into red and green light (eg, red, green, and blue). To produce white backlight illumination containing ingredients etc.). A configuration in which the light emitting diode 38 emits white light can also be used (eg, layer 30 may be omitted if desired).

In a configuration in which the layer 30 emits white light such as white light generated by the phosphorescent material in the layer 30, the white light emitted downward (−Z) from the layer 30 is emitted by the bicolor filter layer 32. , It may be reflected upwards through the pixel array 24 as backlight illumination (ie, layer 32 may be useful for the backlight to be reflected outwards from the array 36). For example, in a configuration where the layer 30 contains red and green quantum dots, the bicolor filter 32 reflects red and green light from the red and green quantum dots, respectively, and directs the backlight outward from the array 36. It may be configured to help reflect. By placing the light luminescence material of the backlight 42 (eg, the material of layer 30) above the diffuser layer 34, the light emitting diode 38 is placed at the edge of the cell rather than the center of the light emitting diode cell (tile) of the array 36. It may be configured to radiate more light towards, thereby helping to improve the uniformity of the backlight illumination.

FIG. 3 is a top view of an exemplary light emitting diode array for the 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 area) 38C. The length D of the edge of the cell 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, less than 25 mm, less than 20 mm, less than 15 mm, less than 10 mm. , Or other suitable size. If desired, an array tiled in a hexagonal shape and an array having a light emitting diode 38 configured with another suitable array pattern may be used. In an array with rectangular cells, each cell may have sides of equal length (eg, each cell has a square outline with four equal length cell edges surrounding each light emitting diode. It may have), or each cell 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 cell 38C is merely exemplary.

If desired, each cell 38C is formed from an array of light emitting diode dies (eg, a plurality of individual light emitting diodes 38 arranged in an array such as a cluster of 2 × 2 light emitting diodes in the center of each cell 38C). It may have a diode light source. For example, the light source 38'in the lower left cell 38C of FIG. 3 is formed from a 2x2 array of light emitting diodes 38 (eg, four separate light emitting diode dies). The diode 38 in the light source 38'may be mounted on a common package board, may be mounted on a printed circuit board board extending across the array 36, or using other suitable arrangements. It may be mounted in the array 36. Generally, 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 four light emitting diodes 38, at least eight light emitting diodes 38, It may include less than 5 light emitting diodes 38, or a light source 38'with other suitable number of light emitting diodes. An exemplary configuration in which each cell 38C has a single light emitting diode 38 may be described herein as an example. However, this is just an example. Each cell 38C may have a light source 38 having one or more arbitrary suitable number of light emitting diodes 38.

FIG. 4 is a side sectional view of an exemplary light emitting diode. The light emitting diode such as the light emitting diode 38 in FIG. 4 may have a terminal such as a contact 58. The contacts 58 may be electrically coupled to the printed circuit or other substrate with a conductive material such as solder (eg, the light emitting diode 38 may be soldered to an array such as the array 36 of FIG. 3 or soldered. It may be installed in another way). The light emitting diode 38 may have an n-type region 54 and a p-type region 56. The regions 54 and 56 may be formed on the substrate 52 from a crystalline semiconductor material such as gallium nitride. The substrate 52 may be formed of a transparent crystalline material such as sapphire or other suitable substrate material. A reflector layer 50 (eg, a distributed Bragg reflector) may be formed on the substrate 52 to help direct the light emitted from the diode 38 laterally.

FIG. 5 is a side sectional view of an exemplary light emitting diode. 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. The reflector 68 may have a square outline (ie, a square installation area when viewed from above), or may have other suitable shapes, and may have a sheet metal (eg, stamped). Sheet metal), metallized polymer film, thin metal plate on plastic carrier, polymer film or dielectric film laminate forming a dielectric mirror (thin film interferometer) on molded plastic carrier, white reflective film (eg, gloss coating, diffuse). A glossy white polymer sheet formed from a white ink layer or other white layer on a polymer carrier covered with a glossy coating such as a reflective white reflector, or a mirror-reflecting white reflector), or other suitable. It may be made from a reflector structure. If desired, the reflector 68 is of a cholesteric liquid crystal in which the Bragg reflectance is controlled by the birefringence (difference in refractive index) and pitch of the material and can be singular or charped for band control. It may be formed from layers or a layer having a sufficiently large refractive index difference (eg, n> 0.1) between adjacent layers such as a laminate of multiple polymer layers or layers of other materials. It may be an interference filter using the laminated body of. The polymer layer laminate is, for example, a laminate in which polyethylene terephthalate (PET) and polymethylmethacrylate (PMMA) films are alternately overlapped, or a laminate in which polyethylene naphthalate (PEN) and PMMA films are alternately overlapped. May be good. The light emitting diode 38 may be soldered or otherwise attached to the metal trace in the printed circuit 60. The central opening of the reflector 68 may receive the light emitting diode 38. The cell in the reflector 68 may have a cross-sectional shape with a curved portion that serves to reflect light from the diode 38 upwards as a backlight illumination 44. In one exemplary configuration, a polymer film (eg, a film coated with a dielectric thin film interference mirror or a glossy white reflective surface) may be embossed using a roller (eg, a heated roller). The film may be thermoformed using the pattern structure above). Following the thermoforming operation to form the curved wall of the reflector 68 in each cell 38C, the opening of each light emitting diode 38 may be cut with a die-cut tool or other cutting device.

As shown in FIG. 5, a transparent structure such as a transparent dome structure 70 may be formed on the light emitting diode 38 to help distribute the light from the light emitting diode 38 in the lateral direction. The dome structure 70 may be formed (as an example) from beads of clear silicone or other transparent polymer. During operation, the light emitting diode 38 emits light refracted by the dome structure 70 away from the Z axis. A ray such as a ray 80 emitted from the light emitting diode 38 may be characterized by an angle A with respect to the normal line n of the light emitting diode 38. The light 80 traveling parallel to the Z dimension is parallel to the surface normal line n (angle A = 0 °). The light 80 traveling parallel to the XY plane travels perpendicular to the Z dimension and surface normal n (ie, A = 90 °). The light 80 traveling in the direction of another angle with respect to the surface normal n is characterized by a value in the middle of the angle A.

Some rays of light 80 are oriented at a relatively large angle A and are reflected upward from the reflector 68 in direction Z (see, eg, a ray 82 reflected from the reflector 68 as the reflected ray 84). sea bream). The other rays of light 80 are oriented at a smaller angle A. For example, the ray 90 is oriented at a smaller angle A with respect to the normal line n. A more angular ray (filtered closer to the edge of the cavity 38C) while reflecting at least a portion of the vertical (A = 0 °) or nearly vertical ray at the center of the cell 38C, such as the ray 86, downward. An angle-dependent filter or other layer that is at least partially reflective, such as layer 96, is provided with a light diffuser 34 and a light emitting diode 38 (and reflections) to help pass the light beam that hits 96) to the reflector 34. It may intervene between the bodies 68). For example, a ray such as the ray 90 is reflected outward and downward (-Z direction) by the layer 96 as shown by the ray 92 and then reflected upward (+ Z direction) as indicated by the ray 94. May be returned.

The layer 96 may be formed from a plurality of dielectric layers 96'(for example, the layer 96 is formed from a layer of silicon oxide, silicon nitride, and / or other inorganic or organic material and has a high refractive index. It may be a thin film interference filter formed from a dielectric laminate in which a material and a low material are alternately overlapped, and / or a layer formed from another dielectric material and / or a layer for forming a thin film interference filter. There may be). In one exemplary configuration, within layer 96 there are 5 layers 96', 3-6 layers 96', 96' with more than 3 layers, or 96' with fewer layers than 10. As an example). A configuration in which the layer 96 is formed from one or more layers of reflective material (eg, a single layer of thick material, or two or more layers of material) without forming a thin film interference filter, or A configuration may be used in which the layer 96 includes both one or more thick coating layers and a thin film interference filter formed from a laminate of dielectric layers. If desired, the partially reflective layer 96 is cholesteric, where the Bragg reflectance is controlled by the birefringence (difference in refractive index) and pitch of the material and can be singular or charped for band control. It may be formed from layers of liquid crystal, or it may have a sufficiently large refractive index difference (eg, n> 0.1) between adjacent layers such as a laminate of multiple polymer layers or layers of other materials. It may be a band pass interference filter using a laminated body of layers having. The polymer layer laminate is, for example, a laminate in which polyethylene terephthalate (PET) and polymethylmethacrylate (PMMA) films are alternately overlapped, or a laminate in which polyethylene naphthalate (PEN) and PMMA films are alternately overlapped. May be good.

The light diffuser 34 and / or other structures within the backlight 42 may comprise any photohomogenizing structure to help ensure uniformization of the backlight 44. For example, a pattern of a light blocking structure and a reflecting structure such as the structure 88 may be formed on the lower surface of the layer 96. Structure 88 is a pseudo-random number of dots, rings, square pads, pads that reflect and block light, patterned to block more light emitted at the center of cell 38C than at the edges of cell 38C. It may contain a pattern, or other structure. The structure 88 serves to allow light at the edges of cell 38C to pass upwards towards film 26 while reflecting and / or absorbing light emitted axially at the center of cell 38C. It may be formed from a patterned ink, a pattern of reflective projections, a patterned angle-dependent thin-film interference filter layer, and / or other light-reflecting and light-scattering structures. This helps to reduce the intermediate hotspots in cell 38C and to level out the variation in light intensity that would otherwise occur when the light from the array 36 is diffused by the light diffuser 34. The structure 88 may be formed on the lower (inner) surface of layer 96 and is also used to support a substrate different from the separate substrate (eg, layer 96 and / or substrate support layer 96). ) May be formed on top of it, or it may be formed at another suitable position in the backlight unit 42.

During operation, at least a portion of the light from the light emitting diode 38 (eg, light 86 in FIG. 5) emitted directly upwards at the center of cell 38C is by an optional structure 88 and / or by layer 96. It is reflected downward. The reflected light is laterally diffused (eg, by being reflected from the cavity reflector 68). Other light, such as light 82 emitted laterally from the light emitting diode 38, may be reflected from the cavity reflector 68 without being reflected from the structure 88 or layer 96, and may pass upward through the diffuser 34. It can function as a backlight 44. The light 90 is reflected from the layer 96 and the reflector 68 before passing upward as light 94.

By allowing the light near the edge of each cell 38C to pass directly through the diffuser 34 while recirculating the light near the center of each cell 38C, the intensity of the light near the edge of each cell 38C is increased in each cell. It can be increased with respect to the intensity of light near the center of 38C. This helps ensure that the backlight 44 is uniform across the surfaces of the light diffuser 34 and the backlight 42. If desired, light scattering particles 72 (eg, microbeads, hollow microspheres, bubbles, and bubbles) in the polymer or other material forming the diffuser layer 34 to help diffuse the emitted light. / Or other light-scattering particles) may be embedded. The light scattering particles 72 may have a refractive index different from that of the polymer constituting the diffuser 34. For example, the index of refraction of the particles 72 may be greater than or less than the index of refraction of the polymer or other material used in forming the layer 34. In addition to or instead of including the light scattering particles 72 in the diffuser 34, light scattering features (convexes, ridges, and / or other protrusions, on the top and / or bottom of the light diffuser 34, Grooves, holes, or other depressions) may be formed. In some configurations, the light may be formed from a photoluminescent layer (eg, a fluorophore and / or quantum dots) in the backlight unit 42 in addition to or instead of the diffuser 34, photoluminescence. It may be diffused using the sense layer 30).

In the exemplary configuration of FIG. 5, a single structure 88 (eg, a single pad) is provided above the light emitting diode 38 in each cell 38C. If desired, a cluster of pads (circular pad, square pad, or other shaped pad) may be formed above each light emitting diode. The density of pads within 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 a gradient structure, such as a pad cluster with a gradient in pad density (eg, pads concentrated on a diode 38), may help to smoothly reduce hot spots in cell 38C. .. If desired (eg, in a configuration in which the layer 96, lens 70, and / or other structure within the backlight unit 42 is configured to homogenize the emitted light without the structure 88. ) Structure 88 may be omitted.

In the exemplary configuration of FIG. 5, a partially reflective layer such as layer 96 (eg, a thin metal layer, a laminate of dielectric film layers, one or more other portions) between the light diffuser 34 and the light emitting diode 38. A reflective layer, etc.) is provided. The layer 96 may be formed as a coating on the lower surface of the diffuser 34, may be embedded in the diffuser 34, and / or may be separate from the diffuser 34. The light reflected downward from the layer 96 may be reflected upward by the cavity reflector 68 and returned. Thereby, the presence of the layer 96 helps to enhance the number or reflection for each ray and thus enhances the homogenization of the light emitted from the light emitting diode array 36 before it passes through the layer 34. If desired, further diffusion may be provided by a diffusion coating on the diffuser 34 and / or another layer within the backlight unit 42 (eg, of the diffuser 34 with embedded light scattering particles 72). A diffusion coating may be formed from the polymer layer on the top surface). The density of the light scattering particles 72 may have a gradient, if necessary.

In a configuration in which the partially reflective layer 96 is formed using a thin film interference filter arrangement, the layer 96 includes a dielectric layer 96'. The layer 96'of the layer 96 is a material such as, for example, an inorganic layer having various refractive indexes (eg, aluminum oxide, silicon oxide, silicon nitride, titanium oxide, other metal oxides, nitrides, and / or oxynitrides). Layers with a high index of refraction and layers with a low index of refraction, which are formed from the above, may be alternately overlapped with each other). The layer 96'may be configured to form a thin film interference filter in which the transmission spectrum of the layer 96 varies as a function of the angle of incidence. As a result, the transmittance T of light at a given wavelength λ, such as the wavelength λb of FIG. 6, which may be related to the blue light emitted from the diode 38, varies depending on the angle of incidence of the light on the layer 96.

As shown in FIG. 6, even if the layer 96 exhibits a transmission spectrum 110 when exposed to light from the diode 38 at an angle A1 (eg, close to 0 ° and parallel to the plane normal n in FIG. 5). Often, the transmission spectrum 112 may be shown for light traveling at an angle near angle A2 (eg, 45 °). Due to the variation of the transmission spectrum of layer 96 as a function of the angle of incidence, the blue light of λb is reflected at least partially when characterized by the angle of incidence A1 (eg, the transmittance T is less than a given amount). When characterized by an A2 greater than A1 or an incident angle greater than A2, the reflectance is even lower (eg, the transmittance T is greater than a given amount). As the curve of FIG. 6 shows, at least a portion of the blue light (eg, light of wavelength λb) emitted from the light emitting diode 38 in the center of cell 38C is directly upward (parallel to the normal line n). ) When emitted, it is reflected and therefore recirculated, whereas blue light emitted at a more oblique angle A can pass when it hits layer 96. This can help reduce the hotspots of light emitted in the center of cell 38C.

The shape of the reflector 68 in each cell 38C is configured to help capture the light diffused laterally outward from the light emitting diode 38 in the center of each cell 38C towards the periphery of each cell 38C. Can further reduce hot spots.

The perspective view of FIG. 7 shows an exemplary configuration of a portion of the reflector 68 covering the exemplary cell 38C. As shown in the example of FIG. 7, the reflector 68 of the cell 38C has each of the walls of the reflector 68 at the same height (eg, for example) with respect to the print circuit 60 along the peripheral edge 38E of the cell 38C. It may be configured to rise to the height H in FIG. 5). As a result, the height of the reflector 68 (distance between the point on the edge 38E and the print circuit 60) along each edge 38E between the opposite cell corners 38D is constant, and the reflector 68. Each edge follows a straight line along the respective cell edge 38E. In this configuration, the contour of the cell 38C taken along the X or Y dimension (eg, the contour 152 between the edges) is an intermediate point along the cell edge 38E (eg, the opposite corners of the edges 38E). It goes up to the apex 38E'at the point of half the distance between the end points of the part). The cross-sectional shape of the cell 38C taken along the diagonal direction (between the respective corners 38D), such as the contour 154 between the corners, rises to the apex at the cell corner 38D. Each vertex of the contour line between the cell edges (eg, the midpoint 38E'of the edge) corresponds to each vertex of the contour line between the cell corners (end of the edge 38E) above the print circuit 60. It is located at the same distance (height H in FIG. 5) as the corner point 38D).

In the example of FIG. 8, the reflector 68 of the cell 38C is configured so that the reflector 68 does not rise to the same height H at each point along the edge 38E. Rather, the edges 38E have a curvilinear shape that descends towards their midpoint. Specifically, each edge 38E is characterized by a maximum height H at the corner 38D (the end point of the curved edge 38E) and a minimum height less than H at the center of the edge 38E. Characterized by the height. 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 follows a curve that hangs down along the cell edge 38E. The cross-sectional shape of the reflector 68 of cell 38C of FIG. 8 taken along the X or Y dimension (eg, contour 152 between cell edges) is less than H at the midpoint along cell edge 38E. The cross-sectional shape of the cell 38C taken along the diagonal direction between the corners 38D, such as the contour 154 between the parts, is (with the reflector 68 of the cell 38C in FIG. 7). Similarly) it rises to the apex of height H at the cell corner 38D. Therefore, each vertex of the contour between the cell edges (point 38E') is located closer to the print circuit 60 than each vertex of the contour between the cell corners (point 38D).

FIG. 9 is a top view of a part of the array 36. The cross-sectional shape between the edges of the reflector 68, such as the contour 152 of FIGS. 7 and 8, is taken along line 204 and the direction of the line of sight is 206. The cross-sectional shape between each part of the reflector 68 such as the contour 154 of FIGS. 7 and 8 is taken along the line 200, and the direction of the line of sight is 202. The edge point 38E'is located at a distance ED in the X and Y directions from the light emitting diode 38, where the ED is half the cell dimension (cell edge length) D. The corner point 38D is located at a distance DD along dimension 208 from the light emitting diode 38, which dimension is defined by an axis oriented at an angle of 45 ° with respect to both the X and Y axes of FIG. ..

10 and 11 are side sectional views of an exemplary reflector configuration of cell 38C in the array 36.

The arrangement shown in FIG. 10 corresponds to the type of configuration shown in FIG. 7, in which the edge 38E is straight. The reflector portion 68-1 corresponds to a portion of the reflector 68 extending between the light emitting diode 38 and the corner 38D of the cell 38C and has a curved shape corresponding to the contour 154 of the reflector 68 of the cell 38C of FIG. It has a contour. The reflector portion 68-2 corresponds to a portion of the reflector 68 extending between the light emitting diode 38 and the edge midpoint 38E'of the cell 38C and has a curved contour that matches the contour 152 of the cell 38C of FIG. Have. As shown in FIG. 10, both points 38E'and 38D in this type of arrangement are located at a distance H from the plane on which the print circuit 60 resides.

The arrangement shown in FIG. 11 corresponds to the type shown in FIG. 8 in which the edge 38E is curved and hangs downward toward the print circuit 60 at a position between the corners 38D. The reflector portion 68-1 of FIG. 11 corresponds to a portion of the reflector 68 extending between the light emitting diode 38 and the corner 38D of the cell 38C and corresponds to the contour 154 of the reflector 68 of the cell 38C of FIG. It has a curved contour. The reflector portion 68-2 corresponds to a portion of the reflector 68 extending between the light emitting diode 38 and the edge midpoint 38E'of the cell 38C and has a curved contour that matches the contour 152 of the cell 38C of FIG. Have. In this type of arrangement, the point 38D at the corner of the cell 38C is located at a distance H from the plane where the print circuit 60 resides, and the midpoint of the edge such as the point 38E'is less than H from the plane where the print circuit 60 resides. It is located at the distance H'.

If desired, the reflector 68 may have a Fresnel shape, in which the reflector 68 is a series of concentric circles, each having a contour that matches the corresponding portion of the contour, such as contour 152 or 154. It has a ring 68-3 of. When a Fresnel reflector structure (reflecting Fresnel lens structure) is used for the reflector 68, the maximum separation between the reflector 68 and the printed circuit 60 in this type of arrangement is in the configuration of the type shown in FIGS. 7 and 8. The distance between the printed circuit 60 and the layer 96 can be minimized as it can be less than the maximum separation between the reflector 68 and the printed circuit 60.

12 and 13 show how the cross-sectional shape of the reflector 68 may have an elliptical or parabolic portion to enhance the homogeneity of the emitted light 44.

FIG. 12 shows a part of the reflector 68 in the cell 38C using an elliptical shape. As shown in FIG. 12, the light emitting diode 38 is associated with a virtual image at position F1 (the position of reflection of the light emitting diode 38 in layer 96). This position may form one of the two focal points of the ellipse used to define a portion of the contour of the reflector 68. In the example of FIG. 12, two exemplary ellipses are shown. The ellipse 220 has a first focal point F1 and a second focal point F2. The ellipse 222 has a first focal point F1 and a second focal point F2'. Focuses F2 and F2'may be in the plane of layer 96. The portion 220'of the ellipse 220 may form a contour between the edges of the reflector 68, such as the contour 152 of FIGS. 7 and 8. The portion 222'of the ellipse 222 may form a contour between the edges of the reflector 68, such as the contour 154 of FIGS. 7 and 8.

FIG. 13 shows a parabolic shape used for the cross-sectional shape portion of the reflector 68 in the cell 38C. As shown in FIG. 13, the reflector 68 may have a cross-sectional shape including a parabolic portion (for example, a cross-sectional shape between edges and / or a cross-sectional shape between corners). The point PF1 may be associated with a parabolic focus that defines the shape of a portion of the contour of the reflector 68. The axis of symmetry of the parabola may be oriented at a non-zero angle (as indicated by axis 242) with respect to the X-axis, or may have other suitable orientations (eg, horizontal axis 240). Please refer to). If desired, the axis of symmetry of the parabola and the focal point of the parabola may have other suitable positions (see, eg, focal point PF2).

The elliptical and parabolic contours of the reflector 68 may help distribute the light from the light emitting diode 38 uniformly on the surface of each cell 38C so that each cell 38C emits a uniform backlight illumination 44. This is demonstrated by the ray trace model. If desired, the reflector 68 may have other shapes. The use of elliptical and parabolic contours on the portion of reflector 68 is exemplary.

14, 15, 16 and 17 show exemplary layers that may be incorporated into the backlight 42.

The optical layer such as the optical film 26 in the backlight 42 may include a thin film interference filter layer. These layers may be formed from a laminate of inorganic and / or organic dielectric layers with alternating refractive indexes (see, eg, the dielectric laminate of layer 300 in FIG. 14). The thin film interference filter may form a broadband (white light) reflector (sometimes called a mirror or partial mirror) and / or a filter that reflects some colors of light more than others. It may be formed (eg, forming a filter with a non-flat visible light reflection spectrum). The thin film interference filter may be configured to transmit unreflected light (eg, to increase light transmittance at non-reflected wavelengths). The dielectric laminate, such as the laminate of layer 300 of FIG. 14, may be formed on a polymer or glass substrate and / or a layer of material that performs other functions (eg, as a thin film interference filter coating layer). May be combined with.

If desired, a luminance improving film (sometimes referred to as a prism film, an optical collimating layer, or an optical collimating prism layer) may be used when collimating the light 44. FIG. 15 is a side sectional view of an exemplary prism film. As shown in FIG. 15, the prism film 302 has a series of parallel ridges 304 extending in the direction of the paper and having a triangular cross-sectional shape. The ridge 304 may face upward (outward) towards the observer to help collimate the light 44 towards the observer.

A microlens array layer, such as the exemplary microlens array layer 306 of FIG. 16, can be used to diffuse and homogenize the light 44. The layer 306 may be relatively thin so as not to excessively increase the thickness of the display 14. For example, layer 306 may be 5-100 micrometers thick, 10 micrometers thick or more, or less than 150 micrometers thick. In the example of FIG. 16, the upper (outward) surface 309 of the layer 306 has an array of convex lenses such as the convex microlens 308, and the lower (inward) surface 311 of the layer 306 is the concave microlens 308. Has an array of concave lenses such as. In general, any of the surfaces of layer 306 may be flat, any of the surfaces of layer 306 may have a convex lens, and / or any of the surfaces of layer 306 may have a concave lens. good. The configuration of FIG. 16 is merely an example. The microlens 308 may have about 15-25 micrometers, 10 micrometers or more, less than 30 micrometers, or other suitable lateral dimensions, and has a height of about 3-20 micrometers. May be good. A non-uniform pattern may be used for the microlens 308 to reduce the moire effect.

The optical layer 26 may include one or more light diffuser layers. In the exemplary configuration of FIG. 17, the light diffuser layer 310, sometimes referred to as a diffuser or diffuser layer, has a polymer substrate such as a substrate 312 in which light scattering particles 314 (eg, titanium oxide particles) are embedded. .. If desired, a diffuser configuration may be used.

FIG. 18 shows an exemplary configuration of a display 14 in which one or more layers, such as these layers, are incorporated into the backlight 42. 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. The light from the array 36 (eg, the blue light from the blue light emitting diode in the array 36) passes upward in the + Z direction through the layer laminated on the array 36 and is backlit by the pixel array 24. As it goes out of the backlight unit 42.

The backlight 42 of the display 14 of FIG. 18 may have a diffuser such as a diffuser layer 310. The diffuser layer 310 may be located above the array 36. The lower surface of the diffuser layer 310 may be coated with a thin film interference filter 320. The filter 320 is from a laminate of dielectric layers with alternating refractive indexes (see, eg, the dielectric laminate of FIG. 14), which is configured to partially transmit and partially reflect blue light. It may be formed. For example, the reflectance of the filter 320 (sometimes referred to as a blue light reflection filter or partial reflection filter) at blue wavelengths is between 50% and 90%, 60% or more, less than 80%, or other suitable values. (For example, the filter may be a partially transmissive blue reflection filter, i.e., it may be partially transmissive to blue light). The filter may have higher or lower reflectance at red and green wavelengths than at blue wavelengths.

Using an optical luminescence layer such as the yellow phosphor layer 316, at least a portion of the light from the light emitting diode of the array 36 (eg, at least a portion of the blue light from the blue light emitting diode in the array 36) is red. It may be converted to green light, thereby allowing layer 316 to radiate white light backlight illumination 44. Some of the red and green light may be emitted downwards. A thin film interference filter such as a filter 318 may be formed on the lower surface of the layer 316 in order to prevent lateral leakage of red and green light. The filter 318 may be formed of a dielectric laminate (eg, the dielectric laminate 300 of FIG. 14) configured to pass blue light while reflecting red and green light (eg, the filter 318). , May be a blue-transmissive, red- and green-reflecting thin-film interference filter).

The microlens array layer 306 (FIG. 16) may be located above the layer 316 or may be used to diffuse the light 44 to prevent hot spots.

The light 44 may collimate towards the observer 20 using one or more prism films 302. In the example of FIG. 18, the display 14 has two prism films 302. The prisms of the film 302 may be oriented at right angles to each other. For example, if the prism of the lower prism film is parallel to the X-axis, the prism of the upper prism film may be parallel to the Y-axis. A reflective splitter 322 may be located above the prism film 302 to help recirculate the light and thereby improve backlight efficiency. The reflective classifier 322 may reflect (recirculate) orthogonally polarized light while passing linearly polarized light along a given axis.

According to one embodiment, a display comprising a plurality of pixels and a backlight configured to generate backlight illumination for the plurality of pixels is provided, and the backlight is configured to emit light. And includes a light source arranged in each of the plurality of cells and a reflector that reflects light from the light source through the plurality of pixels, the reflector is selected from the group consisting of a parabolic portion and an elliptical portion. It has a cross-sectional shape in each cell having a portion.

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

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

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

According to another embodiment, the partially reflective layer is selected from the group consisting of a thin film interference filter having angle-dependent light transmission characteristics, a cholesteric liquid crystal layer, and a laminate of polymer films having alternating refractive indexes. Includes a partially reflective layer.

According to another embodiment, the display comprises a printed circuit, a light emitting diode is attached to the printed circuit, and within each cell the reflector has four linear edges surrounding each one of the light emitting diodes. However, each point along each of the four edges is separated from the printed circuit by a common distance.

According to another embodiment, the display comprises a printed circuit, a light emitting diode is attached to the printed circuit, and within each cell, the reflector is between the four corners and each pair of four corners. It has four curved edges that extend to, and each of the four curved edges has an end point that is a first distance away from the print circuit and a first distance from the print circuit. Also has a midpoint separated by a short second distance.

According to another embodiment, the display comprises a light diffuser layer interposed between an array of pixels and an array of light emitting diodes, a partially reflective layer comprising a coating on the light diffuser layer, and a reflector. , Glossy white reflector, diffuse reflective white reflector, mirror reflective white reflector, laminate of thin film dielectric layers forming a thin film interference mirror, cholesteric liquid crystal layer, and laminate of polymer film with alternating refractive index. Includes reflectors selected from the group consisting of.

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

According to another embodiment, the reflector is selected from the group consisting of a laminate of thin film dielectric layers forming a thin film interference mirror, a cholesteric liquid crystal layer, and a laminate of polymer films having alternating refractive indexes. Including the body.

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

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

According to one embodiment, a display comprising an array of pixels and a backlight configured to produce a backlight illumination for the array of pixels is provided, the backlight being configured to radiate light. It comprises a two-dimensional array of light emitting diode cells, each containing at least one light emitting diode, and a reflector that reflects light from the light emitting diode through an array of pixels, the reflector having a parabolic portion. Each cell has a cross-sectional shape.

According to another embodiment, the display is a light diffuser layer interposed between an array of pixels and an array of light emitting diodes, the light emitting diodes being configured to emit blue light. It further comprises a body layer and a coating on the light diffuser layer that forms a thin film interference filter with angle-dependent transmittance.

According to another embodiment, the light emitting diode is configured to emit blue light.

According to another embodiment, the display comprises a printed circuit, the light emitting diode is attached to the printed circuit, and within each cell the reflector has four corners and four extending between the corners. Each point along each of the four linear edges is separated from the printed circuit by a common distance.

According to another embodiment, the display comprises a printed circuit, a light emitting diode is attached to the printed circuit, and within each cell, the reflector is between the four corners and each pair of four corners. It has four curved edges that extend to, and each of the four curved edges has an end point that is a first distance away from the print circuit and a first distance from the print circuit. Also has a midpoint separated by a short second distance.

According to another embodiment, the reflector includes a layer selected from the group consisting of a layer having a laminate of dielectric layers forming a thin film interference mirror and a glossy white layer.

According to another embodiment, the light emitting diode includes a white light emitting diode.

According to one embodiment, a display comprising an array of pixels and a backlight configured to produce a backlight illumination for the array of pixels is provided, the backlight being configured to radiate light. The reflector comprises a two-dimensional array of light emitting diodes and a reflector that reflects light from the light emitting diode through the array of pixels, and is located within the two-dimensional array of each cell. Each cell has a cross-sectional shape having a portion of.

According to another embodiment, the light emitting diode comprises a blue light emitting diode, and the display is a thin film interference having an angle-dependent transmission with a light diffuser layer interposed between the array of pixels and the array of light emitting diodes. The reflector comprises a coating on a light diffuser layer forming a filter, and the reflector includes a layer selected from the group consisting of a layer having a laminate of dielectric layers forming a thin film interference mirror and a glossy white layer.

According to one embodiment, a display is provided that includes a pixel configured to display an image and a backlight configured to produce a backlight illumination for the pixel, wherein the backlight emits light. A two-dimensional array of light-emitting diode cells, each containing at least one light-emitting diode configured to emit light, and a reflector having a curved cross-sectional shape that reflects light from the light-emitting diode through an array of pixels. It comprises a microlens array layer between the memory and a two-dimensional array of light emitting diode cells.

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

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

According to 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 one embodiment, the light emitting diode includes a blue light emitting diode configured to emit blue light, the first thin film interference filter is configured to partially transmit the blue light, and the second thin film. The interference filter is configured to transmit blue light and reflect the red and green light produced by the phosphor layer in response to the blue light, and the backlight is composed of pixels and a microlens array layer. The first and second prism films between the two prism films and the reflective polarizing element between the second prism film and the pixels are provided.

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 reflect the red and green light generated in the phosphor layer in response to the blue light.

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

According to another embodiment, the backlight comprises a reflective polarizing element between the second prism film and the pixel.

The above is merely an example, and various changes can be made to the embodiments described. The aforementioned embodiments may be implemented individually or in any combination.

Claims (26)

With multiple pixels,
A backlight configured to generate backlight illumination for the plurality of pixels.
A light source that is configured to irradiate light and is arranged in each of a plurality of cells, and is formed in a plane .
A reflector that reflects light from the light source that passes through the plurality of pixels and has a plurality of cross-sectional shapes in each cell, and each cross-sectional shape is selected from a group consisting of a parabolic portion and an elliptical portion . Each of the cross-sectional shapes is oriented substantially parallel to the plane so that more of the light from the light source is directed towards the edge of the cell than the center of the cell. Defined by the reflector and
With backlight, including
A light diffuser layer interposed between the light source and the plurality of pixels,
An angle-dependent filter interposed between the light diffuser layer and the light source,
A layer of photoluminescent material, wherein the photodiffusing layer is interposed between the layer of photoluminescent material and the light source .
display. The display of claim 1, wherein the light source comprises a two-dimensional array of light sources arranged within the two-dimensional array of the respective cells. The display of claim 2, wherein each light source has at least one light emitting diode. The display according to claim 3, wherein the angle-dependent filter is a thin film interference filter having an angle-dependent light transmission characteristic. Further comprising a printed circuit, the light emitting diode is attached to the printed circuit, the reflector having four linear edges surrounding each one of the light emitting diodes in each cell, said four. The display according to claim 4, wherein each point along each of the edges of the is separated from the printed circuit by a common distance. Further equipped with a printed circuit, the light emitting diode is attached to the printed circuit, and in each cell, the reflector extends between four corners and each pair of the four corners. Each of the four curved edges has an end point separated by a first distance from the printed circuit and a second shorter than the first distance from the printed circuit. 4. The display of claim 4, having a midpoint at a distance of. The display of claim 4, wherein the angle dependent filter comprises a coating on the light diffuser layer. The display according to claim 7, wherein the reflector includes a reflector selected from the group consisting of a glossy white reflector, a diffuse reflective white reflector, and a specular reflective white reflector. 7. The reflector includes a reflector selected from the group consisting of a laminate of thin film dielectric layers forming a thin film interference mirror, a cholesteric liquid crystal layer, and a laminate of polymer films having an alternating refractive index. The display described in. The display according to claim 3, wherein the light emitting diode includes a blue light emitting diode. The display of claim 2, wherein each light source comprises at least two light emitting diodes. With an array of pixels
A display comprising a backlight configured to generate a backlight illumination for the array of pixels.
The backlight is
A two-dimensional array of light emitting diode cells in a plane, wherein each of the light emitting diode cells comprises at least one light emitting diode configured to emit light.
A reflector that reflects light from the light emitting diode that passes through the array of pixels.
The reflector has at least three cross-sectional shapes in each cell, each cross-sectional shape has a portion that is parabolic, and each of the parabolic cross-sectional shapes is a twist of the light from the light emitting diode. The at least three cross-sectional shapes are defined by an axis of symmetry that is oriented substantially parallel to the plane so that many are directed towards the edge of the light emitting diode cell rather than the center of the light emitting diode cell, and the at least three cross-sectional shapes are edge to edge. A reflector, including a cross-sectional shape to a portion and a cross-sectional shape from a corner to a corner.
A light diffuser layer interposed between the array of pixels and the array of light emitting diodes,
A display comprising a coating on the light diffuser layer, which forms a thin film interference filter with angle-dependent transmittance. The display according to claim 12, wherein the light emitting diode is configured to emit blue light. Further equipped with a printed circuit, the light emitting diode is attached to the printed circuit, the reflector has four corners in each cell, and four linear edges extending between the corners. 13. The display of claim 13, wherein each point along each of the four linear edges is separated from the printed circuit by a common distance. Further comprising a printed circuit, the light emitting diode is attached to the printed circuit and within each cell the reflector extends between the four corners and each pair of the four corners 4. It has a curved edge of a book, and each of the four curved edges has an end point that is a first distance away from the printed circuit and a distance from the printed circuit that is greater than the first distance. 13. The display of claim 13, having a midpoint separated by a short second distance. 13. The display of claim 13, wherein the reflector comprises a layer selected from the group consisting of a layer having a laminate of dielectric layers forming a thin film interference mirror and a glossy white layer. 12. The display according to claim 12, wherein the light emitting diode includes a white light emitting diode. With an array of pixels
A backlight configured to generate a backlight illumination for the array of pixels.
A two-dimensional array of light-emitting diodes configured to emit light and arranged in a two-dimensional array of cells, wherein the two-dimensional array of light-emitting diodes is formed in a plane. A two-dimensional array of LEDs and
A reflector that reflects light from the light emitting diode that passes through the array of pixels, wherein the reflector has a cross-sectional shape in each cell having a portion having an elliptical shape, and the cross-sectional shape is an edge. A first elliptical shape and a corner portion, including a cross-sectional shape from a portion to an edge portion and a cross-sectional shape from a corner portion to a corner portion, wherein the elliptical shape corresponds to a cross-sectional shape from the edge portion to the edge portion. Each of the cross-sectional shapes includes a second elliptical shape corresponding to the cross-sectional shape from the corner to the corner, where more of the light from the light emitting diode is at the edge of the cell than at the center of the cell. With a reflector, the shape of the first ellipse is different from the shape of the second ellipse, as defined by an axis of cross-section that is substantially parallel to the plane so that it is directed .
With backlight, including
A light diffuser layer interposed between the array of pixels and the array of light emitting diodes,
The reflector comprises a coating on the light diffuser layer forming a thin film interference filter having an angle-dependent transmittance, and the reflector has a layer having a laminate of dielectric layers forming a thin film interference mirror and a glossy white color. A display containing a layer selected from a group of layers. Pixels configured to display images and
A display comprising a backlight configured to generate backlight illumination for the pixels.
The backlight is
A two-dimensional array of light-emitting diode cells, each containing at least one light-emitting diode configured to emit light, wherein the two-dimensional array of light-emitting diode cells is formed in a plane. With a dimensional array
A reflector having a curved cross-sectional shape having one selected from a parabolic shape and an elliptical shape, which reflects light from the light emitting diode passing through the array of pixels and has the cross section. The shape is defined by an axis of symmetry that is substantially parallel to the plane so that more of the light from the light emitting diode is directed towards the edge of the light emitting diode cell rather than the center of the light emitting diode cell. , Reflector,
A microlens array layer between the pixel and the two-dimensional array of light emitting diode cells,
A phosphor layer between the microlens array layer and the two-dimensional array of light emitting diode cells .
display. 19. The display of claim 19, wherein the backlight further comprises a diffuser layer between the fluorescent layer and a two-dimensional array of light emitting diode cells. 20. The display of claim 20, 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. 21. The display of claim 21, wherein the light emitting diode comprises a blue light emitting diode configured to emit blue light. 22. The display of claim 22, wherein the first thin film interference filter is configured to partially transmit the blue light. 23. The second thin film interference filter is configured to transmit the blue light and reflect the red and green light generated in the phosphor layer in response to the blue light. The display described in. 24. The display of claim 24, wherein the backlight comprises first and second prism films between the pixels and the microlens array layer. 25. The display of claim 25, wherein the backlight further comprises a reflective polarizing element between the second prism film and the pixels.

Images